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First principles calculation of material properties of group IV elements and III-V compounds  

E-print Network

of narrow-band-gap semiconductors: InP, InAs, and InSb.f (Ry) bands in ? Si Ge AlP AlAs AlSb InP InAs InSb GaP GaAsband structures for the group IV and group III-V materials Si, Ge, AlP, AlAs, AlSb, InP, InAs, InSb, GaP,

Malone, Brad Dean



Strain driven topological phase transitions in atomically thin films of group IV and V elements in the honeycomb structures  

NASA Astrophysics Data System (ADS)

We have investigated topological electronic properties of freestanding bilayers of group IV (C, Si, Ge, Sn, and, Pb) and V (As, Sb, and, Bi) elements of the periodic table in the buckled and planar honeycomb structures under isotropic strain using first-principles calculations. Our focus is on mapping strain driven phase diagrams and identifying topological phase transitions therein as a pathway for guiding search for suitable substrates to grow two-dimensional (2D) topological insulators (TIs) films. Bilayers of group IV elements, excepting Pb, generally transform from trivial metal \\to topological metal \\to TI \\to topological metal \\to trivial metal phase with increasing strain from negative (compressive) to positive (tensile) values. Similarly, among the group V elements, As and Sb bilayers transform from trivial metal \\to trivial insulator \\to TI phase, while Bi transforms from a topological metal to TI phase. The band gap of 0.5 eV in the TI phase of Bi is the largest we found among all bilayers studied, with the band gap increasing further under tensile strain. Differences in the topological characteristics of bilayers of group V elements reflect associated differences in the strength of the spin–orbit coupling (SOC). We show, in particular, that the topological band structure of Sb bilayer becomes similar to that of a Bi bilayer when the strength of the SOC in Sb is artificially enhanced by a factor of 4. This study provides the first report that As can be a 2D TI under tensile strain. Notably, we found the existence of TI phases in all elemental bilayers we studied, except Pb.

Huang, Zhi-Quan; Hsu, Chia-Hsiu; Chuang, Feng-Chuan; Liu, Yu-Tzu; Lin, Hsin; Su, Wan-Sheng; Ozolins, Vidvuds; Bansil, Arun



Photoelectron spectroscopy and electronic structure of clusters of the group V elements. I. Dimers  

Microsoft Academic Search

The HeI (584 A?) high resolution photoelectron spectra of As+2, Sb+2, and Bi+2 have been obtained with a high temperature molecular beam source. A pure As2 beam was produced by evaporating Cu3As. Sb2 was generated as a mixture with the atoms and tetramers by evaporating the pure element, while Bi2 was generated as a mixture with only the atoms from

Lai-Sheng Wang; Y. T. Lee; D. A. Shirley; K. Balasubramanian; P. Feng



Real elements in covering groups of  

E-print Network

and one gives Q8. In both cases the group is generated by two elements that have the same square. #12;Real8 and one gives Q8. In both cases the group is generated by two elements that have the same squareReal elements in covering groups of elementary abelian 2-groups Rachel Quinlan Covering Groups

Argerami, Martin



E-print Network

, . . . , s}. We call its elements colours. Also consider a finite set of integers {n1, . . . , ns}, ni > 1COHOMOLOGICAL FINITENESS PROPERTIES OF THE BRIN-THOMPSON-HIGMAN GROUPS 2V AND 3V D. H. KOCHLOUKOVA of the Thompson-Higman group V are of type FP. Our methods also give a new proof that both groups are finitely

Sheldon, Nathan D.


Substantial enhancement in intrinsic coercivity on M-type strontium hexaferrite through the increase in magneto-crystalline anisotropy by co-doping of group-V and alkali elements  

SciTech Connect

The effect of d{sup 1} impurity doping in Sr-hexaferrite (SrM) on the magnetic anisotropy is investigated. First-principles calculations revealed that group-V elements (V, Nb) are stabilized with co-doping of alkali elements. Na{sup 1+}/K{sup 1+} doping at Sr{sup 2+}-site is found to be critical to form the d{sup 1} impurities at Fe-site. Experimentally, Na–V doped SrM shows the intrinsic coercivity of ?5.4 kOe, which is ?300% enhancement compared to undoped SrM and comparable value to La–Co co-doped SrM. Finally, the spin-orbit coupling from non-vanishing angular momentum of d{sup 1} impurity in SrM should be a main factor for such a substantial improvement of intrinsic coercivity.

Ahn, Kyunghan, E-mail:; Ryu, Byungki; Korolev, Dmitry; Jae Kang, Young [Materials R and D Center, Samsung Advanced Institute of Technology, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of)] [Materials R and D Center, Samsung Advanced Institute of Technology, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of)



Properties of Group Five and Group Seven transactinium elements  

SciTech Connect

The detection and positive identification of the short-lived, low cross section isotopes used in the chemical studies of the heaviest elements are usually accomplished by measuring their alpha-decay, thus the nuclear properties of the heaviest elements must be examined simultaneously with their chemical properties. The isotopes 224 Pa and 266,267 Bh have been studied extensively as an integral part of the investigation of the heaviest members of the groups five and seven of the periodic table. The half-life of 224 Pa was determined to be 855 plus/minus19 ms by measuring its alpha-decay using our rotating wheel, solid state detector system at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. Protactinium was produced by bombardment of a bismuth target. New neutron rich isotopes, 267 Bh and 266 Bh, were produced in bombardments of a 249 Bk target and their decay was observed using the rotating wheel system. The 266 Bh that was produced decays with a half-life of approximately 1 s by emission of alpha particles with an average energy of 9.25 plus/minus 0.03 MeV. 267 Bh was observed to decay with a 17 s half-life by emission of alpha-particles with an average energy of 8.83 plus/minus 0.03 MeV. The chemical behavior of hafnium, Ha (element 105) was investigated using the fast on-line continuous liquid extraction and detection system SISAK-LISSY. Hafnium was not observed in this experiment following transport and extraction. Protactinium was used as on-line test of the apparatus to determine the experimental efficiency of the entire system. Unfortunately, the amount of protactinium observed after the extraction, compared to the amount produced, was extremely small, only 2.5%. The extraction of the protactinium isotope indicated the efficiency of the apparatus was too low to observe the extraction of hafnium. The chemical behavior of oxychloride compounds of bohrium was investigated by isothermal gas adsorption chromatography in a quartz column at 180, 150, and 75 C. It was found to be less volatile than the corresponding compounds of the lighter group seven homologues, rhenium and technetium, which had been measured previously with the same apparatus. Assuming the bohrium compound to be BhO3Cl, the evaluated standard adsorption enthalpy, and delta-Hads, of BhO3Cl on the quartz surface was calculated from Monte Carlo fits to the volatility data to be -75 kJ/mol. The adsorption enthalpies for TcO3Cl and ReO3Cl are -51 and -61 kJ/mol respectively.

Wilk, Philip A.



Sign elements in symmetric groups Jrn B. Olsson  

E-print Network

Sign elements in symmetric groups Jørn B. Olsson Dept. of Mathematical Sciences University of Copenhagen, Denmark Nagoya, September 4, 2008 Jørn B. Olsson Sign elements in symmetric groups #12 definition of sign elements and sign classes in finite groups. Content of talk: · Generalities about group

Takahashi, Ryo


Calculation of elements of spin groups using generalized Pauli's theorem  

E-print Network

We formulate generalizations of Pauli's theorem on the cases of real and complex Clifford algebras of even and odd dimensions. We give analogues of these theorems in matrix formalism. Using these theorems we present an algorithm for computing elements of spin groups that correspond to elements of orthogonal groups as double cover.

D. S. Shirokov



How to efficiently select an arbitrary Clifford group element  

E-print Network

We give an algorithm which produces a unique element of the Clifford group C_n on n qubits from an integer 0\\le i elements in the group). The algorithm involves O(n^3) operations. It is a variant of the subgroup algorithm by Diaconis and Shahshahani which is commonly applied to compact Lie groups. We provide an adaption for the symplectic group Sp(2n,F_2) which provides, in addition to a canonical mapping from the integers to group elements g, a factorization of g into a sequence of at most 4n symplectic transvections. The algorithm can be used to efficiently select randomelements of C_n which is often useful in quantum information theory and quantum computation. We also give an algorithm for the inverse map, indexing a group element in time O(n^3).

Robert Koenig; John A. Smolin



The Heavy Element Abundance in Groups of Galaxies  

NASA Technical Reports Server (NTRS)

Over the past few years we have analyzed a sample of clusters observed by the Advanced Spacecraft for Cosmology Astrophysics (ASCA) X-ray satellite. We performed spatially resolved X-ray spectroscopy of a sample of 18 relaxed clusters of galaxies with gas temperatures below 4 keV. The spectral analysis was done using ASCA/SIS (Solid state Imaging Spectrometer) data combined with imaging data from ROSAT/PSPC (German acronym for X-ray satellite/Position Sensitive Proportional Counter) and Einstein/IPC (Imaging Proportional Counter) observations. We derived temperature profiles using single-temperature fits for all of the clusters in the sample, and also corrected for the presence of cold gas in the center of so-called 'cooling flow' clusters. For all of the clusters in the sample we derived Si and Fe abundance profiles. For a few of the clusters we also were able to derive Ne and S abundance profiles. We compared the elemental abundances derived at similar overdensities in all of the clusters in the sample. We also compared element mass-to-light ratios for the entire sample. We concluded that the preferential accretion of low entropy, low abundance gas into the potentials of groups and cold clusters can explain most of the observed trends in metallicity. In addition, we discussed the importance of preheating of the intracluster medium by Type II supernovae on the cluster scaling relations.

David, Laurence



Parallel and Serial Grouping of Image Elements in Visual Perception  

ERIC Educational Resources Information Center

The visual system groups image elements that belong to an object and segregates them from other objects and the background. Important cues for this grouping process are the Gestalt criteria, and most theories propose that these are applied in parallel across the visual scene. Here, we find that Gestalt grouping can indeed occur in parallel in some…

Houtkamp, Roos; Roelfsema, Pieter R.



Regularities of Vaporization of Periodic Table Group IVA Element Phosphates  

Microsoft Academic Search

The vaporization of glass-forming phosphates of the periodic table Group IVA elements is studied by high-temperature mass spectrometry. Analyses of qualitative and quantitative vapor compositions have revealed a number of regularities that allow the prediction of the character of the vaporization of polyvalent element phosphates.

S. I. Lopatin; G. A. Semenov



Alternative group V precursors for CVD applications  

NASA Astrophysics Data System (ADS)

The chemical vapor deposition (CVD) techniques used to grow III/V semiconductors films, such as metalorganic vapor phase epitaxy (MOVPE), hydride VPE, chemical beam epitaxy (CBE) and gas source molecular beam epitaxy (GS-MBE), all use hydrides (AsH 3 and PH 3) as the Group V source. However, the hydrides are extremely toxic gases which are stored under high pressure (200-2000 psi). To reduce the safety hazards associated with these gases, alternative Group V precursors have been investigated. Organoarsenic and phosphorous compounds have received the most attention as replacements for AsH 3 and PH 3 because they are typically low vapor pressure liquids, and thus present significantly lower exposure risks than the hydrides. For AsH 3 these have included the methyl, ethyl and butyl-based derivatives RnAsH 3- n, with varying degrees ( n = 1-3) of hydrogen atom substitution. In this paper the growth properties, thermochemistry and toxicity of the various alkylarsine precursors are compared with arsine. Data are presented on the impact of the thermochemistry of these compounds on film electrical properties, and on the effects of precursor composition and purity on overall film quality. The suitability of alternative As-precursors for device applications is demonstrated, and selection criteria are presented for the most effective alkylarsine compound for a particular CVD growth process.

Lum, R. M.; Klingert, J. K.



Elliptic elements in a Weyl group: a homogeneity property  

E-print Network

Let G be a reductive group over an algebraically closed field whose characteristic is not a bad prime for G. Let w be an elliptic element of the Weyl group which has minimum length in its conjugacy class. We show that there ...

Lusztig, George


A renormalisation group method. V. A single renormalisation group step  

E-print Network

This paper is the fifth in a series devoted to the development of a rigorous renormalisation group method applicable to lattice field theories containing boson and/or fermion fields, and comprises the core of the method. In the renormalisation group method, increasingly large scales are studied in a progressive manner, with an interaction parametrised by a field polynomial which evolves with the scale under the renormalisation group map. In our context, the progressive analysis is performed via a finite-range covariance decomposition. Perturbative calculations are used to track the flow of the coupling constants of the evolving polynomial, but on their own perturbative calculations are insufficient to control error terms and to obtain mathematically rigorous results. In this paper, we define an additional non-perturbative coordinate, which together with the flow of coupling constants defines the complete evolution of the renormalisation group map. We specify conditions under which the non-perturbative coordinate is contractive under a single renormalisation group step. Our framework is essentially combinatorial, but its implementation relies on analytic results developed earlier in the series of papers. The results of this paper are applied elsewhere to analyse the critical behaviour of the 4-dimensional continuous-time weakly self-avoiding walk and of the 4-dimensional n-component $|\\varphi|^4$ model. In particular, the existence of a logarithmic correction to mean-field scaling for the susceptibility can be proved for both models, together with other facts about critical exponents and critical behaviour.

David C. Brydges; Gordon Slade



I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V Literary and Artistic Studies Dept/Program English elements in our literary tradition. Lecture and discussion will focus on the historical, social, and political contexts of the poets and poems we study, as well as on poetic form and diction. In addition, ENLT

Vonessen, Nikolaus


Photoelectron Spectra and Valence Shell Orbital Structures of Groups V and VI Hydrides  

Microsoft Academic Search

Photoelectron spectra are reported for the hydrides of group V and VI elements. Vibrational structure has been observed in bands associated with all but the inner-most valence orbitals. It has been used to obtain changes in bond angles or bond distances which result from the ionization of successive molecular orbitals. Ionization from the inner (1a1) orbitals of the hydrides has

A. W. Potts; W. C. Price



Doping of indium phosphide with group IV elements  

SciTech Connect

This paper studies the doping of single crystals of indium phosphide (InP) with group IV elements using data obtained by measuring the total charge concentration of additives and carriers. Single crystals of indium phosphide were grown by the Czochralski method from liquid melts with a liquid hermetic seal in quartz cubicles. The total impurity concentration was determined by atomic-absorption analysis with + or - 10% error. In order to explain the behavior of germanium and tin in indium phosphide, the authors consider the bond energies of additives in indium phosphide and their tetrahedral radii. The authors conclude that the established higher amphoteric character of germanium with respect to tin is probably explained by the moduli of elasticity of the doped crystal.

Zakharenkov, L.F.; Samorukov, B.E.; Zykov, A.M.



Bactericidal properties of group IIA and group V phospholipases A2  

Microsoft Academic Search

Group V phospholipase A2 (PLA2) is a recently characterized 14-kDa secretory PLA2 of mammalian heart and macrophage-derived cells. Group IIA PLA2, which is structurally close to group V PLA2, has been shown to kill Gram-positive bacteria in vitro and to prevent symptoms of Gram-positive infection in vivo. We studied the antibacterial properties of fully active recombinant rat group IIA and

J. O. Grönroos; Veli J. O. Laine; Marcel J. W. Janssen; Maarten R. Egmond; Timo J. Nevalainen



Determination of the CKM Element V(Ub)  

SciTech Connect

The precise determination of the CKM matrix element |V{sub ub}| is crucial in testing the Standard Model mechanism for CP violation. From a sample of 88 million B{bar B} pairs collected with the BABAR detector, charmless semileptonic B decays are selected using simultaneous requirements on the electron energy, E{sub e}, and the invariant mass squared of the electron-neutrino pair, q{sup 2}. The partial branching fraction, unfolded for detector effects, is determined in a region of the q{sup 2}-E{sub e} plane where the dominating semileptonic decays to charm mesons are highly suppressed. Theoretical calculations based on the Heavy Quark Expanion allows for a determination of |V{sub ub}| = (3.95 {+-} 0.27{sub -0.42}{sup +0.58} {+-} 0.25) x 10{sup -3}, where the errors represent experimental, heavy quark parameters and theoretical uncertainties, respectively.

Fortin, Dominique; /Victoria U.




E-print Network

FREELY BRAIDED ELEMENTS IN COXETER GROUPS, II R.M. Green and Abstract. We continue the study of freely braided elements of simply lace* *d Coxeter groups, which classes of reduced expressions for an element of a * *simply laced Coxeter group is shown

Green, Richard M.


Not every p-group can be generated by elements of the same order  

E-print Network

Not every p-group can be generated by elements of the same order E.A. O'Brien, Carlo M. Scoppola of equal orders? Since the semidihedral group of order 16 cannot be generated by elements of the same order p-group P to fail to be generated by a set of elements, all having the same order

O'Brien, Eamonn



E-print Network

for the same element w of a Coxeter group are equivalent under the equivalence relation generated by braid FREELY BRAIDED ELEMENTS IN COXETER GROUPS R.M. Green and Abstract. We introduce a notion of "freely braided element" for simply la* *ced Cox- eter groups. We

Green, Richard M.


I. ASCRC General Education Form Group V: Literary & Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary & Artistic Studies Dept/Program Drama from historical, cultural, aesthetic, psychological, literary and socio-political perspectives with respect to structure and significance within literary and artistic traditions, including emergent

Vonessen, Nikolaus


Summary of the TeV33 working group  

SciTech Connect

This summary of the TeV33 working group at Snowmass reports on work in the areas of Tevatron store parameters, the beam-beam interaction, Main Injector intensity (slip stacking), antiproton production, and electron cooling.

Bagley, P.P.; Bieniosek, F.M.; Colestock, P. [and others



Investigation of group IVA elements combined with HAXPES and first-principles calculations  

NASA Astrophysics Data System (ADS)

The core level and valence band spectra of group IVA elements were investigated with hard x-ray photoemission spectroscopy (HAXPES) photon energy of 7.939 keV by bulk sensitive manner. The survey and valance band spectra were presented, relative peaks intensity are discussed by thinking about inelastic mean free path (IMFP) and photoionization cross section of photoelectrons (PICS). In order to understand bulk band structures, valence bands are compared with the calculated ones by considering PICS, IMFP and total energy resolution. The calculated results by GGA, HSE06 and GW0 methods are simply discussed by comparing with experiment spectra.

Cui, Y.-T.; Li, G.-L.; Oji, H.; Son, J.-Y.



Platinum-group elements: so many excellent properties  

USGS Publications Warehouse

The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

Zientek, Michael L.; Loferski, Patricia J.




E-print Network



The elemental composition of the Sun II. The iron group elements Sc to Ni  

E-print Network

We redetermine the abundances of all iron group nuclei in the Sun, based on neutral and singly-ionised lines of Sc, Ti, V, Mn, Fe, Co and Ni in the solar spectrum. We employ a realistic 3D hydrodynamic model solar atmosphere, corrections for departures from local thermodynamic equilibrium (NLTE), stringent line selection procedures and high quality observational data. We have scoured the literature for the best quality oscillator strengths, hyperfine constants and isotopic separations available for our chosen lines. We find $\\log \\epsilon_\\mathrm{Sc}=3.16\\pm0.04$, $\\log \\epsilon_\\mathrm{Ti}=4.90\\pm0.04$, $\\log \\epsilon_\\mathrm{V}=3.89\\pm0.08$, $\\log \\epsilon_\\mathrm{Cr}=5.62\\pm0.04$, $\\log \\epsilon_\\mathrm{Mn}=5.42\\pm0.04$, $\\log \\epsilon_\\mathrm{Fe}=7.47\\pm0.04$, $\\log \\epsilon_\\mathrm{Co}=4.93\\pm0.05$ and $\\log \\epsilon_\\mathrm{Ni}=6.20\\pm0.04$. Our uncertainties factor in both statistical and systematic errors (the latter estimated for possible errors in the model atmospheres and NLTE line formation). The ...

Scott, Pat; Grevesse, Nicolas; Bergemann, Maria; Sauval, A Jacques



Structure, function, and regulation of Group V phospholipase A 2  

Microsoft Academic Search

The hydrolysis of membrane phospholipid by phospholipase A2 (PLA2) is a key step in the production of inflammatory eicosanoids. Recent cell studies have shown that secretory group V PLA2 (gVPLA2) is involved in agonist-induced eicosanoid biosynthesis in mouse P388D1 cell line, mast cells, and transfected HEK 293 cells. gVPLA2 is homologous to other group II PLA2 family members but has

Wonhwa Cho



I. ASCRC General Education Form Group Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group Group V Literary and Artistic Studies Dept/Program Applied to poetry's rich cultural tradition through the study of sound and sense, structure and meaning, and form. Poems are studied within their cultural, historical, and philosophical contexts. Writing assignments

Vonessen, Nikolaus


I. ASCRC General Education Form Group Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group Group V Literary and Artistic Studies Dept/Program Applied:// WTS 120L introduces students to the study of how readers make meaning of texts and how texts influence readers. This course focuses specifically on developing strategies essential to interpreting literary

Vonessen, Nikolaus


I. ASCRC General Education Form Group V. Literary & Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V. Literary & Artistic Studies Dept/Program English Course:// Critical study of the relationship between literature and its cinematic adaptations. Discussion for analysis of the structure and significance of these forms. Focus will be on literary/filmic analysis

Vonessen, Nikolaus


I. ASCRC General Education Form Group V: Literary & Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary & Artistic Studies Dept/Program Drama. Through an introduction to dramatic literature, literary criticism, as well as analysis and response with respect to structure and significance within literary and artistic traditions, including emergent

Vonessen, Nikolaus



E-print Network

5 5 4 4 3 3 2 2 1 1 D D C C B B A A CRICKET V2.0 NETWORKS AND MOBILE SYSTEMS GROUP CSAIL@MIT LEAD DESIGNER: NISSANKA B. PRIYANTHA 6310-0335-01 A MTS450CA CRICKET RS232 Crossbow Technology 41 Daggett Drive



E-print Network



Group sequential tests for delayed responses Lisa V. Hampson  

E-print Network

Group sequential tests for delayed responses Lisa V. Hampson Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK. Christopher through a series of examples. We define error spending versions of these new designs which handle

Budd, Chris


Benchmarking of the 99-group ANSL-V library  

SciTech Connect

The purpose of this paper is to present thermal benchmark data testing results for the BAPL-1, TRX-1, and SEEP-1 lattices, using selected processed cross-sections from the ANSL-V 99-group library. 7 refs., 1 tab.

Wright, R.Q.; Ford, W.E. III; Greene, N.M.; Petrie, L.M.; Primm, R.T. III; Westfall, R.M.



Finite groups in which elements of the same order outside the center are conjugate  

Microsoft Academic Search

In this paper, we prove that if $G$ is a finite group in which elements of the same order outside the center are conjugate, then $G$ is abelian or is isomorphic to $S_3$, the symmetry group of degree 3.

Guohua Qian; Wujie Shi; Xingzhong You



Parametrisations of elements of spinor and orthogonal groups using exterior exponents  

E-print Network

We present new parametrizations of elements of spinor and orthogonal groups of dimension 4 using Grassmann exterior algebra. Theory of spinor groups is an important tool in theoretical and mathematical physics namely in the Dirac equation for an electron.

Nikolay Marchuk



Vapor phase growth of group 3, 4, and 5 compounds by HCl transport of elements  

NASA Technical Reports Server (NTRS)

Technique has been devised for vapor-phase epitaxial growth of group 3, 4, and 5 binary, ternary, or quaternary compounds by HCl transport of the constituent elements or dopants. Technique uses all the constituents of the alloy system in their elemental form. Transport of these elements by an HCl + H2 carrier gas facilitates their transport as subchlorides.

Tyagi, R. C.; Debnam, W. J., Jr.; Mcnear, M. F.; Crouch, R. K.; Breckenridge, R. A.



Rhenium-osmium isotope systematics and platinum group element concentrations: Loess and the upper continental crust  

Microsoft Academic Search

[1] Abstract: We investigate the use of loess as a proxy for the concentration and isotopic composition of highly siderophile elements, specifically Os, in the upper continental crust. The 187 Os\\/ 188 Os, platinum group element, and Re concentrations of 16 loess samples from China, Europe, and South America, previously analyzed for major, trace element, and Sr and Nd isotope

Bernhard Peucker-Ehrenbrink; Bor-ming Jahn



Z .Chemical Geology 157 1999 219234 z /Quantifying the platinum group elements PGEs and gold in  

E-print Network

Z .Chemical Geology 157 1999 219­234 z /Quantifying the platinum group elements PGEs and gold for analyzing low abundances of the platinum group elements PGEs and gold has been developed using Z .cation--Ru, Rh, Pd, Os, Ir and Pt and gold Au ) Corresponding author are typically present in common terrestrial


High-pressure phases in B group element alloys: a new sort of electronic phase  

Microsoft Academic Search

General relationships are discussed for phase formation in B group element alloys with increasing pressure. The main tendency is determined by the homology rule: the effect of pressure is to change the phase equilibria in the same way as when one component is replaced by a heavier element in the same group. The sequence of relative configurations of stability regions

V. F. Degtyareva; E. G. Ponyatovskii



Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006  

USGS Publications Warehouse

Every three years the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements revises tables giving the directions of the poles of rotation and the prime meridians of the planets, satellites, minor planets, and comets. This report introduces improved values for the pole and rotation rate of Pluto, Charon, and Phoebe, the pole of Jupiter, the sizes and shapes of Saturn satellites and Charon, and the poles, rotation rates, and sizes of some minor planets and comets. A high precision realization for the pole and rotation rate of the Moon is provided. The expression for the Sun's rotation has been changed to be consistent with the planets and to account for light travel time ?? 2007 Springer Science+Business Media B.V.

Seidelmann, P. K.; Archinal, B. A.; A'Hearn, M. F.; Conrad, A.; Consolmagno, G. J.; Hestroffer, D.; Hilton, J. L.; Krasinsky, G. A.; Neumann, G.; Oberst, J.; Stooke, P.; Tedesco, E. F.; Tholen, D. J.; Thomas, P. C.; Williams, I. P.



Expression and characterization of human group V phospholipase A 2  

Microsoft Academic Search

Group V phospholipase A2 (GV-PLA2) has been shown to be involved in signal transduction and inflammatory processes in cellular studies, but the physical and biochemical properties of this important enzyme have been unclear. We report the over-expression and characterization of GV-PLA2. The GV-PLA2 cDNA was synthesized from human heart polyA+ mRNA by RT-PCR, and an expression construct containing the GV-PLA2

Yijun Chen; Edward A. Dennis



Calculations of stopping powers of 100 eV-30 keV electrons in 31 elemental solids  

SciTech Connect

We present calculated electron stopping powers (SPs) for 31 elemental solids (Li, Be, glassy C, graphite, diamond, Na, Mg, K, Sc, Ti, V, Fe, Y, Zr, Nb, Mo, Ru, Rh, In, Sn, Cs, Gd, Tb, Dy, Hf, Ta, W, Re, Os, Ir, and Bi). These SPs were determined with an algorithm previously used for the calculation of electron inelastic mean free paths and from energy-loss functions (ELFs) derived from experimental optical data. The SP calculations were made for electron energies between 100 eV and 30 keV and supplement our earlier SP calculations for ten additional solids (Al, Si, Cr, Ni, Cu, Ge, Pd, Ag, Pt, and Au). Plots of SP versus atomic number for the group of 41 solids show clear trends. Multiple peaks and shoulders are seen that result from the contributions of valence-electron and various inner-shell excitations. Satisfactory agreement was found between the calculated SPs and values from the relativistic Bethe SP equation with recommended values of the mean excitation energy (MEE) for energies above 10 keV. We determined effective MEEs versus maximum excitation energy from the ELFs for each solid. Plots of effective MEE versus atomic number showed the relative contributions of valence-electron and different core-electron excitations to the MEE. For a maximum excitation energy of 30 keV, our effective MEEs agreed well for Be, graphite, Na, Al, and Si with recommended MEEs; a difference for Li was attributed to sample oxidation in the SP measurements for the recommended MEE. Substantially different effective MEEs were found for the three carbon allotropes (graphite, diamond, and glassy C)

Tanuma, S. [Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Powell, C. J.; Penn, D. R. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States)



Slope stability analysis by nite elements D. V. GRIFFITHS and P. A. LANE{  

E-print Network

Slope stability analysis by ®nite elements D. V. GRIFFITHS� and P. A. LANE{ The majority of slope to all engineers. The ®nite element method represents a powerful alternative ap- proach for slope, regarding the failure mechanism. Slope failure in the ®nite element model occurs `naturally' through


The Relationship Between Innovativeness and Selected Elements of Group Structure.  

ERIC Educational Resources Information Center

This study was an attempt to build upon the prior work in the area of the diffusion of innovations and innovativeness. Broadly stated, the study attempted to answer the question: What is the relationship between selected characteristics of intact groups and their innovativeness? The sample consisted of six elementary schools in Massachusetts which…

Crandall, David P.


Integrated learning in practical machine element design course: a case study of V-pulley design  

NASA Astrophysics Data System (ADS)

To achieve an effective integrated learning in Machine Element Design course, it is of importance to bridge the basic knowledge and skills of element designs. The multiple core learning leads the pathway which consists of two main parts. The first part involves teaching documents of which the contents are number of V-groove formulae, standard of V-grooved pulleys, and parallel key dimension's formulae. The second part relates to the subjects that the students have studied prior to participating in this integrated learning course, namely Material Selection, Manufacturing Process, Applied Engineering Drawing, CAD (Computer Aided Design) animation software. Moreover, an intensive cooperation between a lecturer and students is another key factor to fulfill the success of integrated learning. Last but not least, the students need to share their knowledge within the group and among the other groups aiming to gain knowledge of and skills in 1) the application of CAD-software to build up manufacture part drawings, 2) assembly drawing, 3) simulation to verify the strength of loaded pulley by method of Finite Element Analysis (FEA), 4) the software to create animation of mounting and dismounting of a pulley to a shaft, and 5) an instruction manual. The end product of this integrated learning, as a result of the above 1 to 5 knowledge and skills obtained, the participating students can create an assembly derived from manufacture part drawings and a video presentation with bilingual (English-Thai) audio description of Vpulley with datum diameter of 250 mm, 4 grooves, and type of groove: SPA.

Tantrabandit, Manop



Determinations of quark mixing matrix elements $|V_{cd}|$ and $|V_{cs}|$ from leptonic and semileptonic $D$ Decays  

E-print Network

With the recent measurements of purely leptonic $D^+_{(s)}$ decays and semileptonic $D$ decays in conjunction with decay constants $f_{D^+_{(s)}}$ and form factors $f^{\\pi(K)}_+(0)$ calculated in LQCD, we extract the magnitudes of $V_{cd}$ and $V_{cs}$ to be $|V_{cd}|=0.218\\pm0.005$ and $|V_{cs}|=0.987\\pm0.016$. Compared to those given in PDG2013, the precisions of these newly extracted $|V_{cd}|$ and $|V_{cs}|$ are improved by more than 2.0 and 1.5 factors, respectively. With the newly extracted $|V_{cd}|$ and $|V_{cs}|$ together with other CKM matrix elements given in PDG2013, we check the unitarity of the CKM matrix, which are $|V_{ud}|^2+|V_{cd}|^2+|V_{td}|^2=0.997\\pm0.002$, $|V_{us}|^2+|V_{cs}|^2+|V_{ts}|^2=1.027\\pm0.032$ and $|V_{cd}|^2+|V_{cs}|^2+|V_{cb}|^2=1.023\\pm0.032$.

Rong, G; Ma, H L



Determinations of quark mixing matrix elements $|V_{cd}|$ and $|V_{cs}|$ from leptonic and semileptonic $D$ Decays  

E-print Network

With the recent measurements of purely leptonic $D^+_{(s)}$ decays and semileptonic $D$ decays in conjunction with decay constants $f_{D^+_{(s)}}$ and form factors $f^{\\pi(K)}_+(0)$ calculated in LQCD, we extract the magnitudes of $V_{cd}$ and $V_{cs}$ to be $|V_{cd}|=0.218\\pm0.005$ and $|V_{cs}|=0.987\\pm0.016$. Compared to those given in PDG2013, the precisions of these newly extracted $|V_{cd}|$ and $|V_{cs}|$ are improved by more than 2.0 and 1.5 factors, respectively. With the newly extracted $|V_{cd}|$ and $|V_{cs}|$ together with other CKM matrix elements given in PDG2013, we check the unitarity of the CKM matrix, which are $|V_{ud}|^2+|V_{cd}|^2+|V_{td}|^2=0.997\\pm0.002$, $|V_{us}|^2+|V_{cs}|^2+|V_{ts}|^2=1.027\\pm0.032$ and $|V_{cd}|^2+|V_{cs}|^2+|V_{cb}|^2=1.023\\pm0.032$.

G. Rong; Y. Fang; H. L. Ma



Re-187 Os-187 Isotopic and Highly Siderophile Element Systematics of Group IVB Irons  

NASA Technical Reports Server (NTRS)

Study of the magmatic iron meteorite groups permits constraints to be placed on the chemical and isotopic composition of parent bodies, and the timing of, and crystal-liquid fractionation processes involved in the crystallization of asteroidal cores. Here we examine Re-Os isotopic and trace elemental systematics of group IVB irons. Compared to most irons, the irons comprising this group are enriched in some of the most refractory siderophile elements, yet highly-depleted in most volatile siderophile elements. These characteristics have been attributed to processes such as high temperature condensation of precursor materials and oxidation in the parent body. Most recently it has been suggested that both processes may be involved in the chemical complexity of the group. Here, high precision isotopic and highly siderophile element (HSE) concentrations are used to further examine these possible origins, and the crystallization history of the group. In addition, we have begun to assess the possibility of relating certain ungrouped irons with major groups via multi-element, trace element modeling. In a companion abstract, the isotopic and trace element systematics of the ungrouped iron Tishomingo are compared with the IVB irons.

Honesto, J.; McDonough, W. F.; Walker, R. J.; McCoy, T. J.; Ash, R. D.




E-print Network

INTRODUCTION There are six platinum group elements (PGE): ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium , whereas the others, with densities of ~22 , are the heavy PGE. Osmium, Ir and Ru are refractory


Platinum group elements in the environment: emissions and exposure.  


PGEs (Pt, Pd, Ru, Ir, and Os) are a relatively new group of anthropogenic pollutants. Specific useful properties of these metals (high resistance to chemical corrosion over a wide range of temperatures, high melting point, high mechanical resistance, and high plasticity) have fomented rapid growth of new and existing applications in various economic and industrial sectors. These metals are not only used in the chemical, petrochemical, electrical, and electronics industries but also PGE use, in various industries, has dramatically increased emissions of these metals to the environment; emissions from vehicle catalytic converters and hospital wastewater discharges are particularly significant. The environmental benefits of using PGEs in vehicle catalytic converters are clear. These metals catalyze the conversion of toxic constituents of exhaust fumes (CO, HCs, NOxs) to water, CO2, and molecular nitrogen. As a result of adverse physico-chemical and mechanical influences on the catalyst surface, PGEs are released from this layer and are emitted into the environment in exhaust fumes. Research results indicate that the levels of such emissions are rather low (ng km(-1)). However, recent data show that certain chemical forms of PGEs emitted from vehicles are, or may be, bioavailable. Hence, the potential for PGEs to bioaccumulate in different environmental compartments should be studied, and, if necessary, addressed. The use of Pt in anticancerous drug preparations also contributes to environmental burdens. Pt, when administered as a drug, is excreted in a patient's urine and, as a consequence, has been observed in hospital and communal wastewater discharges. Few studies have been published that address bioavailability, mode of penetration into live organisms, or environmental fate of PGEs. The toxic effect of these metals on living organisms, including humans, is still in dispute and incompletely elucidated. Contrary to some chlorine complexes of Pt, which most frequently cause allergic reactions, the metallic forms of PGEs are probably inert; however, they may undergo transformation to biologically available forms after release to the environment. Because exposure to PGEs may result in health hazards, it is necessary to evaluate the risks of human exposure to these metals. Available data show that the highest exposed groups (Leceniewska et al. 2001) are individuals who work in refineries, chemical plants, electronics plants, jewelry production, oncological wards (medical personnel), and road maintenance; also highly exposed are women who have silicone breast implants. The effects of PGE exposure in live organisms include the following: asthma, miscarriage, nausea, hair loss, skin diseases, and, in humans, other serious health problems. As production and use of PGEs grow, there is a commensurate need to generate additional experimental and modeling data on them; such data would be designed to provide a better understanding of the environmental disposition and influence on human health of the PGEs. PMID:19110940

Dubiella-Jackowska, Aleksandra; Polkowska, Zaneta; Namie?nik, Jacek



A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments  

E-print Network

This paper is a companion article to the review paper by the present author devoted to the classification of matter constituents (chemical elements and particles) and published in the first part of the proceedings of The Second Harry Wiener International Memorial Conference (see quant-ph/0310155). It is mainly concerned with a group-theoretical approach to the Periodic Table of the neutral elements based on the noncompact group SO(4,2)xSU(2).

M. R. Kibler



RNAi Components Are Required for Nuclear Clustering of Polycomb Group Response Elements  

Microsoft Academic Search

SUMMARY Drosophila Polycomb group (PcG) proteins silence homeotic genes through binding to Polycomb group response elements (PREs). Fab-7 is a PRE-containing regulatory element from the homeotic gene Abdominal-B. When present in multiple copies in the genome, Fab-7 can induce long-distance gene contacts that enhance PcG-dependent silencing. We show here that components of the RNA interfer- ence (RNAi) machinery are involved

Charlotte Grimaud; Frédéric Bantignies; Manika Pal-Bhadra; Utpal Bhadra; Giacomo Cavalli



Concentrations of platinum group elements in 122 U.S. coal samples  

USGS Publications Warehouse

Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.



The Structural Basis for Promoter -35 Element Recognition by the Group IV ? Factors  

PubMed Central

The control of bacterial transcription initiation depends on a primary ? factor for housekeeping functions, as well as alternative ? factors that control regulons in response to environmental stresses. The largest and most diverse subgroup of alternative ? factors, the group IV extracytoplasmic function ? factors, directs the transcription of genes that regulate a wide variety of responses, including envelope stress and pathogenesis. We determined the 2.3-Å resolution crystal structure of the ?35 element recognition domain of a group IV ? factor, Escherichia coli ?E4, bound to its consensus ?35 element, GGAACTT. Despite similar function and secondary structure, the primary and group IV ? factors recognize their ?35 elements using distinct mechanisms. Conserved sequence elements of the ?E ?35 element induce a DNA geometry characteristic of AA/TT-tract DNA, including a rigid, straight double-helical axis and a narrow minor groove. For this reason, the highly conserved AA in the middle of the GGAACTT motif is essential for ?35 element recognition by ?E4, despite the absence of direct protein–DNA interactions with these DNA bases. These principles of ?E4/?35 element recognition can be applied to a wide range of other group IV ? factors. PMID:16903784

Lane, William J; Darst, Seth A



On the Solubility of Group IV Elements (Ti, Zr, Hf) in Liquid Aluminum Below 800C  

E-print Network

On the Solubility of Group IV Elements (Ti, Zr, Hf) in Liquid Aluminum Below 800°C O. Dezellus, B January 9, 2014) The solubility of group IV transition metals Ti, Zr, and Hf in liquid Al was measured that solubility values obtained after a cooling or a heating step were fully consistent. The present results

Paris-Sud XI, Université de


On a group-theoretical approach to the periodic table of chemical elements  

E-print Network

This paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from the table and the general lines of a programme for a quantitative approach to the properties of chemical elements are developed on the basis of the group SO(4,2)xSU(2).

Maurice Robert Kibler



Conserved Structural Elements in the V3 Crown of HIV-1 gp120  

SciTech Connect

Binding of the third variable region (V3) of the HIV-1 envelope glycoprotein gp120 to the cell-surface coreceptors CCR5 or CXCR4 during viral entry suggests that there are conserved structural elements in this sequence-variable region. These conserved elements could serve as epitopes to be targeted by a vaccine against HIV-1. Here we perform a systematic structural analysis of representative human anti-V3 monoclonal antibodies in complex with V3 peptides, revealing that the crown of V3 has four conserved structural elements: an arch, a band, a hydrophobic core and the peptide backbone. These are either unaffected by or are subject to minimal sequence variation. As these regions are targeted by cross-clade neutralizing human antibodies, they provide a blueprint for the design of vaccine immunogens that could elicit broadly cross-reactive protective antibodies.

Jiang, X.; Burke, V; Totrov, M; Williams, C; Cardozo, T; Gorny, M; Zolla-Pazner, S; Kong, X



A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments  

Microsoft Academic Search

This paper is a companion article to the review paper by the present author\\u000adevoted to the classification of matter constituents (chemical elements and\\u000aparticles) and published in the first part of the proceedings of The Second\\u000aHarry Wiener International Memorial Conference (see quant-ph\\/0310155). It is\\u000amainly concerned with a group-theoretical approach to the Periodic Table of the\\u000aneutral elements

M. R. Kibler



A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments  

Microsoft Academic Search

This paper is a companion article to the review paper by the present author devoted to the classification of matter constituents (chemical elements and particles) and published in the first part of the proceedings of The Second Harry Wiener International Memorial Conference (see quant-ph\\/0310155). It is mainly concerned with a group-theoretical approach to the Periodic Table of the neutral elements

M. R. Kibler



Analysis of the trace element content of coals from the Wabaunsee Group southeastern Nebraska  

SciTech Connect

Eight coal samples obtained from the Honey Creek, Lorton, Wamego, Elmo, and Nodaway coals of the Wabaunsee Group (Upper Pennsylvanian) were analyzed for their concentration of certain trace elements. Analysis of the data suggests (a) a general decrease of trace element concentrations away from the Precambrian Nemaha Arch in a basinward direction, and (b) the post-diagenetic emplacement of lead, zinc and cadmium typical of mid-continent coals.

Kaplan, S.S.; Carr, J.D.; Kelter, P.B.



Counting Conjugacy Classes of Elements of Finite Order in Lie Groups  

E-print Network

Using combinatorial techniques, we answer two questions about simple classical Lie groups. Define $N(G,m)$ to be the number of conjugacy classes of elements of finite order $m$ in a Lie group $G$, and $N(G,m,s)$ to be the number of such classes whose elements have $s$ distinct eigenvalues or conjugate pairs of eigenvalues. What is $N(G,m)$ for $G$ a unitary, orthogonal, or symplectic group? What is $N(G,m,s)$ for these groups? For some cases, the first question was answered a few decades ago via group-theoretic techniques. It appears that the second question has not been asked before; here it is inspired by questions related to enumeration of vacua in string theory. Our combinatorial methods allow us to answer both questions.

Tamar Friedmann; Richard P. Stanley



Differentiation of Muller's Chromosomal Elements D and E in the Obscura Group of Drosophila  

PubMed Central

Twenty-two markers located on Muller's elements D or E have been mapped by in situ hybridization in six species of the obscura group of Drosophila and in D. melanogaster. The obscura species can be grouped into a Palearctic cluster (D. subobscura, D. madeirensis and D. guanche) and a Nearctic one (D. pseudoobscura, D. persimilis and D. miranda). Eleven of the probes contain known genes: E74, Acp70A, Est5, hsp28/23, hsp83, emc, hsp70, Xdh, Acph-1, Cec and rp49. The remaining probes are recombinant phages isolated from a D. subobscura genomic library. All these markers hybridize to the putative homologous chromosome or chromosomal arm of elements D and E. Thus, these elements have conserved their genic content during species divergence. Chromosomal homologies proposed previously for each element among the species of the same cluster have been compared with the present results. The distribution of markers within each element has changed considerably as inferred from pairwise comparisons of obscura species included in the two different clusters. Only chromosomal segments defined by closely linked markers have been conserved: one such segment has been detected in element D and three in element E between D. subobscura and D. pseudoobscura. PMID:8878680

Segarra, C.; Ribo, G.; Aguade, M.



Elemental abundance analyses with DAO spectrograms: XXXII. HR 6455 (A3 III), ? Aqr (A3 V), ? Lep (F2 V), and 1 Boo (A1 V)  

NASA Astrophysics Data System (ADS)

We examine the sharp-lined stars HR 6455 (A3 III, v sin i = 8.7 km s-1) and ? Lep (F2 V, v sin i = 13.5 km s-1) as well as ? Aqr (A3 V, v sin i = 81 km s-1) and 1 Boo (A1 V, v sin i = 59 km s-1) to increase the number consistently analyzed A and F stars using high dispersion and high S/N (?200) spectrograms obtained with CCD detectors at the long Coudé camera of the 1.22-m telescope of the Dominion Astrophysical Observatory. Such studies contribute to understanding systematic abundance differences between normal and non-magnetic main-sequence band chemically peculiar A and early F stars. LTE fine analyses of HR 6455, ? Aqr, and 1 Boo using Kurucz's ATLAS suite programs show the same general elemental abundance trends with differences in the metal richness. Light and iron-peak element abundances are generally solar or overabundant while heavy element and rare earth element abundances are overabundant. HR 6455 is an evolved Am star while ? Aqr and 1 Boo show the phenomenon to different extents. Most derived abundances of ? Lep are solar. Table 3 is available at the CDS via

Yüce, K.; Adelman, S. J.; Gulliver, A. F.; Hill, G.



The Probability that a Pair of Elements of a Finite Group are Conjugate  

E-print Network

Let $G$ be a finite group, and let $\\kappa(G)$ be the probability that elements $g$, $h\\in G$ are conjugate, when $g$ and $h$ are chosen independently and uniformly at random. The paper classifies those groups $G$ such that $\\kappa(G) \\geq 1/4$, and shows that $G$ is abelian whenever $\\kappa(G)|G| group $S_n$, the paper shows that $\\kappa(S_n) \\leq C/n^2$ for an explicitly determined constant $C$. This bound leads to an elementary proof of a result of Flajolet \\emph{et al}, that $\\kappa(S_n) \\sim A/n^2$ as $n\\rightarrow \\infty$ for some constant $A$. The same techniques provide analogous results for $\\rho(S_n)$, the probability that two elements of the symmetric group have conjugates that commute.

Blackburn, Simon R; Wildon, Mark



Platinum-group elements in porphyry copper deposits: a reconnaissance study  

Microsoft Academic Search

Summary Sulphide and flotation concentrates from 33 porphyry copper deposits have been investigated for platinum-group elements (PGE), Au, Cu and platinum-group minerals (PGM). The major sulphides in the samples studied are chalcopyrite and pyrite. Bornite is less frequent and molybdenite occurs in traces only. PGM (merenskyite, sperrylite and an unidentified Pd-Sb telluride) have been found as inclusions in chalcopyrite.

M. Tarkian; B. Stribrny



Pentacarbonyl(? 2-vinylferrocene)metal(0) complexes of Group 6 elements: synthesis and characterization  

Microsoft Academic Search

Photolysis of hexacarbonylmetal(0) complexes of the Group 6 elements in the presence of vinylferrocene in an n-hexane solution at ?15°C yields pentacarbonyl (?2-vinylferrocene)metal(0) complexes as the sole photo-substitution product, different from the general reaction pattern observed for the same Group 6 metal carbonyls with other olefins. M(CO)5(?2-vinylferrocene) complexes (M=Cr, Mo, W) could be isolated from the solution and characterized by

Saim Özkar; Ceyhan Kayran; Nazlan Demir



Radiochemical Separation of Group 5 Elements. Model Experiments for Investigation of Dubnium Chemical Behaviour  

SciTech Connect

Chemical behaviour of group 5 elements in the aqueous hydrofluoric acid solutions was studied. The radiochemical method for the cation exchange separation of Nb (Pa) and Ta from Zr, Hf and lanthanides is presented. The developed scheme allows excluding of the presence of SF heavy actinides in fractions of separated elements. On the basis of the data of the present work, it is possible to suggest the following order of the stability of the fluoride complexes of group 4 and 5 elements: Nb {approx_equal} Pa > Zr > Hf > Ta. The order of the complex formation is in agreement with theoretical predictions. This analytical procedure can be used in future heavy nuclei synthesis experiments for the separation of dubnium (Db) from other reactions products and for its chemical identification.

Tereshatov, E. E.; Bozhikov, G. A.; Aksenov, N. V.; Starodub, G. Ya.; Vostokin, G. K.; Shishkin, S. V.; Dmitriev, S. N. [Flerov Laboratory of Nuclear Reactions (FLNR), JINR, Dubna RU-141980 (Russian Federation); Bruchertseifer, H.; Gaeggeler, H. W. [Paul Scherrer Institute (PSI), Villigen CH-5232 (Switzerland)



A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments  

E-print Network

A Group-Theoretical Approach to the Periodic Table of Chemical Elements: Old and New Developments as an invited talk to The Second Harry Wiener International Memorial Conference: "The Periodic Table in The Mathematics of the Periodic Table, D.H. Rouvray and R.B. King, Eds., Nova Science Publishers, New York, 2005

Paris-Sud XI, Université de


Structural Properties of of Group IV B Element Rutherfordium by First Principles Theory  

Microsoft Academic Search

The structural and electronic properties of Rutherfordium, the newest group IV B element, have been evaluated by first principles density functional theory in scalar relativistic formalism with and without spin-orbit coupling and compared with the known experimental and theoretical properties of its homologue Hf. It is found that it will crystallize in the hexagonal close packed structure with metallic character.

Jyoti Gyanchandani; S. K. Sikka



Platinum Group Elements Enhance the Allergic Immune Response by Acting on Dendritic Cells  

Microsoft Academic Search

Background: Atmospheric pollution may play a role in the immune response to allergens either directly or by entering the food chain. While particulate platinum group elements (PLGE) emitted by catalytic converters can be considered biologically inert, approximately 10% of these species accumulate in the environment as bioavailable soluble forms. Methods: We challenged in vitro human immature and mature monocyte-derived dendritic

Clara Paolucci; Jessica Ponti; Monica V. Fabbri; Daniela Breda; Enrico Sabbioni; Samuele E. Burastero



High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements  

Microsoft Academic Search

The main atmospheric parameters and abundances of the iron-group elements (vanadium, chromium, iron, cobalt and nickel) are determined for 62 red giant `clump' stars revealed in the Galactic field by the Hipparcos orbiting observatory. The stars form a homogeneous sample with the mean value of temperature Teff = 4750 +\\/- 160K, of surface gravity log g = 2.41 +\\/- 0.26

E. Puzeras; G. Tautvaisiene; J. G. Cohen; D. F. Gray; S. J. Adelman; I. Ilyin; Y. Chorniy



Mobility of rhenium, platinum group elements and organic carbon during black shale weathering  

Microsoft Academic Search

This study investigates the effects of black shale weathering on the Re–Os isotope system, platinum group element concentrations and the degradation of organic matter. Samples from a weathering profile in Late Devonian (?365 Myr) Ohio Shale show a pronounced decrease (?77%) in organic carbon (Corg) near the present soil surface, relative to the interior portion of the outcrop. A similar

Lillie A Jaffe; Bernhard Peucker-Ehrenbrink; Steven T Petsch



Ab initio energy-adjusted pseudopotentials for elements of groups 13-17  

Microsoft Academic Search

Quasi-relativistic energy-adjusted ab initio pseudopotentials for the elements of groups 13-17 up to atomic number 53 (I) are presented together with corresponding energy-optimized valence basis sets. Test calculations for atomic excitation and ionization energies show the reliability of the derived pseudopotentials and basis sets.

Andreas Bergner; Michael Dolg; Wolfgang Küchle; Hermann Stoll; Heinzwerner Preuß



Platinum group elements in raptor eggs, faeces, blood, liver and kidney  

Microsoft Academic Search

The increased use of platinum group elements (PGEs) in automobile catalysts and their emission into the environment has led to a concern over environmental and particularly biological accumulation. Specimens of samples from raptors are useful for the investigation of the impact of PGEs because these birds are found in both urban and rural environments and are invariably at the top

Kristine H. Ek; Sebastien Rauch; Gregory M. Morrison; Peter Lindberg




EPA Science Inventory

The effect of varying physical and chemical properties of activated carbons on adsorption of elemental mercury [Hg(0)] was studied by treating two activated carbons to modify their surface functional groups and pore structures. Heat treatment (1200 K) in nitrogen (N2), air oxidat...


33 CFR 155.5052 - Response plan development and evaluation criteria for nontank vessels carrying group V petroleum...  

...for nontank vessels carrying group V petroleum oil. 155.5052 Section 155...for nontank vessels carrying group V petroleum oil. Owners or operators of nontank vessels that carry group V petroleum oil as fuel or cargo must meet...



Is the evolutionary history of the O-type P element in the saltans and willistoni groups of Drosophila similar to that of the canonical P element?  


We studied the occurrence of O-type P elements in at least one species of each subgroup of the saltans group, in order to better understand the phylogenetic relationships among the elements within the saltans group and with those of species belonging to the willistoni group. We found that the O-type subfamily has a patchy distribution within the saltans group (it does not occur in D. neocordata and D. emarginata), low sequence divergence among species of the saltans group as well as in relation to species of the willistoni group, a lower rate of synonymous substitution for coding sequences compared to Adh, and phylogenetic incongruities. These findings suggest that the evolutionary history of the O-type subfamily within the saltans and willistoni groups follows the same model proposed for the canonical subfamily of P elements, i.e., events of horizontal transfer between species of the saltans and willistoni groups. PMID:18034216

de Setta, Nathalia; Loreto, Elgion L S; Carareto, Claudia M A



Trace-element composition and zoning in clinopyroxene- and amphibole-group minerals: Implications for element partitioning and evolution of carbonatites  

NASA Astrophysics Data System (ADS)

The present work is a first comprehensive study of the trace-element composition and zoning in clinopyroxene- and amphibole-group minerals from carbonatites, incorporating samples from 14 localities worldwide (Afrikanda, Aley, Alnö, Blue River, Eden Lake, Huayangchuan, Murun, Oka, Ozernaya Varaka, Ozernyi, Paint Lake, Pinghe, Prairie Lake, Turiy Mys). The new electron-microprobe data presented here significantly extend the known compositional range of clinopyroxenes and amphiboles from carbonatites. These data confirm that calcic and sodic clinopyroxenes from carbonatites are not separated by a compositional gap, instead forming an arcuate trend from nearly pure diopside through intermediate aegirine-augite compositions confined to a limited range of CaFeSi 2O 6 contents (15-45 mol%) to aegirine with < 25 mol% of CaMgSi 2O 6 and a negligible proportion of CaFeSi 2O 6. A large set of LA-ICPMS data shows that the clinopyroxenes of different composition are characterized by relatively low levels of Cr, Co and Ni (? 40 ppm) and manifold variations in the concentration of trivalent lithophile and some incompatible elements (1-150 ppm Sc, 26-6870 ppm V, 5-550 ppm Sr, 90-2360 ppm Zr, and nil to 150 ppm REE), recorded in some cases within a single crystal. The relative contribution of clinopyroxenes to the whole-rock Rb, Nb, Ta, Th and U budget is negligible. The major-element compositional range of amphiboles spans from alkali- and Al-poor members (tremolite) to Na-Al-rich Mg- or, less commonly, Fe-dominant members (magnesiohastingsite, hastingsite and pargasite), to calcic-sodic, sodic and potassic-sodic compositions intermediate between magnesio-ferrikatophorite, richterite, magnesioriebeckite, ferri-nyböite and (potassic-)magnesio-arfvedsonite. In comparison with the clinopyroxenes, the amphiboles contain similar levels of tetravalent high-field-strength elements (Ti, Zr and Hf) and compatible transition elements (Cr, Co and Ni), but are capable of incorporating much higher concentrations of Sc and incompatible elements (up to 500 ppm Sc, 43 ppm Rb, 1470 ppm Sr, 1230 ppm Ba, 80 ppm Pb, 1070 ppm REE, 140 ppm Y, and 180 ppm Nb). In some carbonatites, amphiboles contribute as much as 25% of the Zr + Hf, 15% of the Sr and 35% of the Rb + Ba whole-rock budget. Both clinopyroxenes and amphiboles may also host a significant share (~ 10%) of the bulk heavy-REE content. Our trace-element data show that the partitioning of REE between clinopyroxene (and, in some samples, amphibole) and the melt is clearly bimodal and requires a revision of the existing models assuming single-site REE partitioning. Clinopyroxenes and amphiboles from carbonatites exhibit a diversity of zoning patterns that cannot be explained exclusively on the basis of crystal chemistry and relative compatibility of different trace-element in these minerals. Paragenetic analysis indicates that in most cases, the observed zoning patterns develop in response to removal of selected trace elements by phases co-precipitating with clinopyroxene and amphibole (especially magnetite, fluorapatite, phlogopite and pyrochlore). With the exception of magnesiohastingsite-richterite sample from Afrikanda, the invariability of trace-element ratios in the majority of zoned clinopyroxene and amphibole crystals implies that fluids are not involved in the development of zoning in these minerals. The implications of the new trace-element data for mineral exploration targeting REE, Nb and other types of carbonatite-hosted rare-metal mineralization are discussed.

Reguir, Ekaterina P.; Chakhmouradian, Anton R.; Pisiak, Laura; Halden, Norman M.; Yang, Panseok; Xu, Cheng; Kynický, Jind?ich; Couëslan, Chris G.



Finite groups in which every pair of elements of the same order is either conjugate or inverse-conjugate  

Microsoft Academic Search

For a group G, elements a and b are said to be inverse-conjugate if ? is conjugate to b. We classify all finite groups in which every pair of elements of the same order is either conjugate or inverse-conjugate. The groups with this property are either small soluble groups, which are explicitly listed, or the groups L 2;(7), M11, M23

Caiheng Li



The Element Effect Revisited: Factors Determining Leaving Group Ability in Activated Nucleophilic Aromatic Substitution Reactions  

PubMed Central

The “element effect” in nucleophilic aromatic substitution reactions (SNAr) is characterized by the leaving group order, F > NO2 > Cl ? Br > I, in activated aryl halides. Multiple causes for this result have been proposed. Experimental evidence shows that the element effect order in the reaction of piperidine with 2,4-dinitrophenyl halides in methanol is governed by the differences in enthalpies of activation. Computational studies of the reaction of piperidine and dimethylamine with the same aryl halides using the polarizable continuum model (PCM) for solvation indicate that polar, polarizability, solvation, and negative hyperconjugative effects are all of some importance in producing the element effect in methanol. In addition, a reversal of polarity of the C–X bond from reactant to transition state in the case of ArCl and ArBr compared to ArF also contributes to their difference in reactivity. The polarity reversal, and hyperconjugative influences have received little or no attention in the past. Nor has differential solvation of the different transition states been strongly emphasized. An anionic nucleophile, thiolate, gives very early transition states and negative activation enthalpies with activated aryl halides. The element effect is not established for these reactions. We suggest that the leaving group order in the gas phase will be dependent on the exact combination of nucleophile, leaving group, and substrate framework. The geometry of the SNAr transition state permits useful, qualitative conceptual distinctions to be made between this reaction and other modes of nucleophilic attack. PMID:23057717

Senger, Nicholas A.; Bo, Bo; Cheng, Qian; Keeffe, James R.; Gronert, Scott; Wu, Weiming



Fully relativistic study of intermetallic dimers of group-1 elements K through element 119 and prediction of their adsorption on noble metal surfaces  

NASA Astrophysics Data System (ADS)

Spectroscopic properties of group-1 M2 and MAu (M = K, Rb, Cs, Fr, and element 119) were calculated using the 4c-DFT method. The results show that the relativistic contraction and stabilization of the ns(M) AO result in the inversion of trends both in atomic and molecular properties in group 1 beyond Cs. Electronegativity ? of the elements proves to decrease from Cs, the most electropositive element of all elements, to element 119, with its ? value approaching that of Na. Due to the largest relativistic effects on the 8s(119) AO in group 1, bonding in (119)2 appears to be stronger than that of K2, while bonding in 119Au should be the weakest out of all group-1 MAu. Using calculated dissociation energies of M2, sublimation enthalpies, ?Hsub, of Fr of 77 kJ/mol and element 119 of 94 kJ/mol were estimated using a linear correlation between these quantities in the chemical group. Using the M-Au binding energies, the adsorption enthalpies, -?Hads, of 106 kJ/mol on gold, 76 kJ/mol on platinum, and 63 kJ/mol on silver were estimated for element 119 via a correlation with known ?Hads in the chemical group. These moderate ?Hads values are indicative of a possibility of chromatography adsorption studies of element 119 on the noble metal surfaces.

Pershina, V.; Borschevsky, A.; Anton, J.



Beating the Miscibility Barrier between Iron Group Elements and Magnesium by High-Pressure Alloying  

SciTech Connect

Iron and magnesium are almost immiscible at ambient pressure. The low solubility of Mg in Fe is due to a very large size mismatch between the alloy components. However, the compressibility of Mg is much higher than that of Fe, and therefore the difference in atomic sizes between elements decreases dramatically with pressure. Based on the predictions of ab initio calculations, we demonstrate in a series of experiments in a multianvil apparatus and in electrically and laser-heated diamond anvil cells that high pressure promotes solubility of magnesium in iron. At the megabar pressure range, more than 10 at. % of Mg can dissolve in Fe and then the alloy can be quenched to ambient conditions. A generality of the concept of high-pressure alloying between immiscible elements is demonstrated by its application to two other Fe group elements, Co and Ni.

Dubrovinskaia, N. [Bayerisches Geoinstitut, Universitaet Bayreuth, D-95440 Bayreuth (Germany); Lehrstuhl fuer Kristallographie, Physikalisches Institut, Universitaet Bayreuth, 95440 Bayreuth (Germany); Dubrovinsky, L.; Kantor, I. [Bayerisches Geoinstitut, Universitaet Bayreuth, D-95440 Bayreuth (Germany); Crichton, W. A. [European Synchrotron Radiation Facility, Grenoble 38043 (France); Dmitriev, V. [Swiss-Norwegian Beam Lines at ESRF, F-38043 Grenoble (France); Prakapenka, V.; Shen, G. [Consortium for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States); Vitos, L.; Johansson, B. [Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvaegen 23, SE-100 44 Stockholm (Sweden); Condensed Matter Theory Group, Department of Physics, Uppsala University, S-751 21 Uppsala (Sweden); Ahuja, R. [Condensed Matter Theory Group, Department of Physics, Uppsala University, S-751 21 Uppsala (Sweden); Abrikosov, I. A. [Department of Physics and Measurement Technology, Linkoepings University (Sweden)



Canonical P elements are transcriptionally active in the saltans group of Drosophila.  


Up to now, investigations of expression and regulation of P transposable element have been almost exclusively carried out with the Drosophila melanogaster canonical P element. Analyzing eight species of the saltans group, we detected transposase mRNA in germline tissues of D. saltans and D. prosaltans and repressor mRNA in somatic tissues of D. saltans and D. sturtevanti. Sequencing analysis suggested that these transcripts might belong to the canonical subfamily and that they can be transpositionally active only in D. saltans. d(N) and d(S) values of Adh and the P element suggested that the sequences found in D. saltans and D. prosaltans might have been present in the ancestor of the saltans subgroup and that the sequence found in D. sturtevanti might have been horizontally transferred from D. saltans. PMID:15383905

de Castro, Juliana Polachini; Carareto, Cláudia Márcia A



Adhesion and friction behavior of group 4 elements germanium, silicon, tin, and lead  

NASA Technical Reports Server (NTRS)

Adhesion and friction studies were conducted with thin films of the group IV elements silicon, germanium, tin, and lead ion plated on the nickel (011) substrate. The mating surface was gold (111). Contacts were made for the elements in the clean state and with oxygen present. Adhesion and friction experiments were conducted at very light loads of 1 to 10 g. Sliding was at a speed of 0.7 mm/min. Friction results indicate that the more covalently bonded elements silicon and germanium exhibit lower adhesion and friction than the more metallic bonded tin and lead. The adhesion of gold to germanium was observed, and recrystallization of the transferred gold occurred. Plastic flow of germanium was seen with sliding. Oxygen reduced, but did not eliminate, the adhesion observed with germanium and silicon.

Buckley, D. H.



Chapter v: Reports of Divisions, Commissions and Working Groups  

NASA Astrophysics Data System (ADS)

This chapter presents the reports of Business Meeting of IAU Divisions, Commissions, Working Groups and Program Groups, held during the IAU XXVI General Assembly in Prague, 14-25 August 2006. The reports have been written by the out-going presidents and chairpersons.



Formation of Ni–Cu–Platinum Group Element sulfide mineralization in the Sudbury Impact Melt Sheet  

Microsoft Academic Search

Summary The Ni–Cu–Platinum Group Element (PGE) sulfide deposits of the Sudbury Structure have provided a major portion of the world’s total nickel production and their host rocks have been the subject of numerous research studies, yet a number of perplexing problems remain to be solved. On the one hand, studies seeking to explain the formation of the Sudbury Structure have

R. R. Keays; P. C. Lightfoot



Platinum-group elements: quantification in collected exhaust fumes and studies of catalyst surfaces  

Microsoft Academic Search

Automotive catalytic converters, in which Pt, Pd and Rh (platinum-group elements; PGEs) are the active components for eliminating several noxious components from exhaust fumes, have become the main source of environmental urban pollution by PGEs. This work reports on the catalyst morphology through changes in catalyst surface by scanning electron microscopy\\/energy dispersive X-ray spectroscopy (SEM\\/EDX) and laser-induced breakdown spectrometry (LIBS)

M. A Palacios; M. M Gómez; M Moldovan; G Morrison; S Rauch; C McLeod; R Ma; J Laserna; P Lucena; S Caroli; A Alimonti; F Petrucci; B Bocca; P Schramel; S Lustig; M Zischka; U Wass; B Stenbom; M Luna; J. C Saenz; J Santamar??a; J. M Torrens



Group velocity of light in V and ?-types cylindrical quantum dots with electromagnetically induced transparency  

NASA Astrophysics Data System (ADS)

This paper aims to investigate group velocity of light and slow light in cylindrical quantum dot. By considering a V-Type three level system under EIT, group velocity equation of cylindrical quantum dot is found and the effects of different parameters such as control laser amplitude, radius and height of cylindrical QD and polarization of light are investigated. Group velocity of light in V-Type is compared with group velocity of light in ?-Type.

Mirzaei, M.; Askari, H. R.; Raki, Z.



Stable splittings, spaces of representations and almost commuting elements in Lie groups  

NASA Astrophysics Data System (ADS)

In this paper the space of almost commuting elements in a Lie group is studied through a homotopical point of view. In particular a stable splitting after one suspension is derived for these spaces and their quotients under conjugation. A complete description for the stable factors appearing in this splitting is provided for compact connected Lie groups of rank one.By using symmetric products, the colimits $\\Rep(\\Z^n, SU)$, $\\Rep(\\Z^n,U)$ and $\\Rep(\\Z^n, Sp)$ are explicitly described as finite products of Eilenberg-MacLane spaces.

Adem, Alejandro; Cohen, Frederick R.; Gómez, José Manuel



The Gestalt Principles of Similarity and Proximity Apply to Both the Haptic and Visual Grouping of Elements  

E-print Network

Abstract. When designing multi-sensory displays it is necessary to consider human perceptual capabilities and understand how people find patterns and how they organise individual elements into structures and groups. Gestalt theory, originally described in 1910, attempts to explain the way people perceive and recognise patterns. The early studies of Gestalt principles of grouping were predominantly concerned with visual perception, although more recently they have been investigated for auditory perception. This paper focuses on how individuals use the sense of touch (haptics) to group display elements using the Gestalt principles of similarity and proximity. A direct comparison is made with the visual grouping of elements using the same two principles of similarity and proximity. The hypothesis of the experiment described in this paper is that people will use touch to group display elements in the same way they group elements visually. Overall we found that a significant number of subjects used texture or colour to group the elements when there was an equal spacing between the elements. This supports our hypothesis that the principle of similarity is equally applicable for both visual (colour) and haptic (texture) grouping. Similarly, when subjects perceived an unequal spacing between the elements they used spatial position to determine groupings. These results support our hypothesis that the principle of

Dempsey Chang; Keith V. Nesbitt; Kevin Wilkins


Finite groups in which any two elements of the same order are either fused or inverse-fused  

Microsoft Academic Search

Elements a, b of a group G are said to be fused or inverse-fused if there exists ??Aut(G) such that a = b or a = (b) respectively. This paper gives a classification of all finite groups in which any two elements of the same order are fused orinverse-fused.

Cai Heng Li; Cheryl E. Praeger



Project EARTH-11-GMH2: Variations in Osmium isotopes and platinum group elements in the Atlantic Ocean  

E-print Network

Project EARTH-11-GMH2: Variations in Osmium isotopes and platinum group elements in the Atlantic by formation of carbonates. Osmium isotopes 187 Os/188 Os and platinum group element (PGE) concentrations (Os measurement of femtomoles of osmium and the 187 Os/188 Os ratio in seawater" Science 282: 272-274. Oxburgh, R

Henderson, Gideon


Cytogenetic mapping of the Muller F element genes in Drosophila willistoni group.  


Comparative genomics in Drosophila began in 1940, when Muller stated that the ancestral haploid karyotype of this genus is constituted by five acrocentric chromosomes and one dot chromosome, named A to F elements. In some species of the willistoni group such as Drosophila willistoni and D. insularis, the F element, instead of a dot chromosome, has been incorporated into the E element, forming chromosome III (E + F fusion). The aim of this study was to investigate the scope of the E + F fusion in the willistoni group, evaluating six other species. Fluorescent in situ hybridization was used to locate two genes of the F element previously studied-cubitus interruptus (ci) and eyeless (ey)-in species of the willistoni and bocainensis subgroups. Moreover, polytene chromosome photomaps corresponding to the F element (basal portion of chromosome III) were constructed for each species studied. In D. willistoni, D. paulistorum and D. equinoxialis, the ci gene was located in subSectction 78B and the ey gene in 78C. In D. tropicalis, ci was located in subSection 76B and ey in 76C. In species of the bocainensis subgroup, ci and ey were localized, respectively, at subsections 76B and 76C in D. nebulosa and D. capricorni, and 76A and 76C in D. fumipennis. Despite the differences in the subsection numbers, all species showed the same position for ci and ey. The results confirm the synteny of E + F fusion in willistoni and bocainensis subgroups, and allow estimating the occurrence of this event at 15 Mya, at least. PMID:25134938

Pita, Sebastián; Panzera, Yanina; Lúcia da Silva Valente, Vera; de Melo, Zilpa das Graças Silva; Garcia, Carolina; Garcia, Ana Cristina Lauer; Montes, Martín Alejandro; Rohde, Claudia



The influence of the group V/III molar precursor ratio on the structural properties  

E-print Network

, the precursors were temporally embedded in a nitrogen carrier gas stream, such that the total flow and pressureThe influence of the group V/III molar precursor ratio on the structural properties of InGaN layers, University of California, Irvine, CA 92697-2375, USA The influence of the group V/III molar precursor ratio

Dietz, Nikolaus


I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V Literary and Artistic Studies Dept/Program MCLL/Russian; cross-listed with Liberal Studies Course # MCLG 306V; LS 306V Course Title Introduction to 19th Century critical perspectives. This course examines a wide range of literary genres (novels, poems, short stories

Vonessen, Nikolaus


Molecular Characterization of Timothy Grass Pollen Group V Allergens  

Microsoft Academic Search

Phl p V is the dominant allergen of timothy grass (Phleum pratense) with two isoforms having the apparent molecular weights of 38 (Phl p Va) and 32 kD (Phlp Vb) under Western blot conditions. Two-dimensional electrophoresis\\/immunoblotting reveals that each isoform is split into at least four isoallergens. Structural differences in the isoforms are shown by N-terminal sequencing (only 60% identity),

Wolf-Meinhard Becker; Albrecht Bufe; Arnd Petersen; Max Schlaak



Reconstructing a V W plane from its collineation group  

E-print Network

a particular Planar Ternary Ring (R, T) of order p2 , p an odd prime, which gives rise to the non P Ã? L, is constructed as follows: (i) P = {(x, y) : x, y R} {(x) : x R} {()}, (ii) L = {[a, b) I [], (x) I [a], () I [a, b]. 3 A V W plane Let F be a finite field of order p2 , p an odd prime

Magliveras, Spyros


Partitioning of Si and platinum group elements between liquid and solid Fe-Si alloys  

NASA Astrophysics Data System (ADS)

Crystallization of the Earth's inner core fractionates major and minor elements between the solid and liquid metal, leaving physical and geochemical imprints on the Earth's core. For example, the density jump observed at the Inner Core Boundary (ICB) is related to the preferential partitioning of lighter elements in the liquid outer core. The fractionation of Os, Re and Pt between liquid and solid during inner core crystallization has been invoked as a process that explains the observed Os isotopic signature of mantle plume-derived lavas (Brandon et al., 1998; Brandon and Walker, 2005) in terms of core-mantle interaction. In this article we measured partitioning of Si, Os, Re and Pt between liquid and solid metal. Isobaric (2 GPa) experiments were conducted in a piston-cylinder press at temperatures between 1250 °C and 1600 °C in which an imposed thermal gradient through the sample provided solid-liquid coexistence in the Fe-Si system. We determined the narrow melting loop in the Fe-Si system using Si partitioning values and showed that order-disorder transition in the Fe-Si solid phases can have a large effect on Si partitioning. We also found constant partition coefficients (DOs, DPt, DRe) between liquid and solid metal, for Si concentrations ranging from 2 to 12 wt%. The compact structure of Fe-Si liquid alloys is compatible with incorporation of Si and platinum group elements (PGEs) elements precluding solid-liquid fractionation. Such phase diagram properties are relevant for other light elements such as S and C at high pressure and is not consistent with inter-elemental fractionation of PGEs during metal crystallization at Earth's inner core conditions. We therefore propose that the peculiar Os isotopic signature observed in plume-derived lavas is more likely explained by mantle source heterogeneity (Meibom et al., 2002; Baker and Krogh Jensen, 2004; Luguet et al., 2008).

Morard, G.; Siebert, J.; Badro, J.



Composition, apparatus, and process, for sorption of gaseous compounds of group II-VII elements  


Scavenger compositions are disclosed, which have utility for effecting the sorptive removal of hazardous gases containing Group II-VII elements of the Periodic Table, such as are widely encountered in the manufacture of semiconducting materials and semiconductor devices. Gas sorption processes including the contacting of Group II-VII gaseous compounds with such scavenger compositions are likewise disclosed, together with critical space velocity contacting conditions pertaining thereto. Further described are gas contacting apparatus, including mesh structures which may be deployed in gas contacting vessels containing such scavenger compositions, to prevent solids from being introduced to or discharged from the contacting vessel in the gas stream undergoing treatment. A reticulate heat transfer structure also is disclosed, for dampening localized exothermic reaction fronts when gas mixtures comprising Group II-VII constituents are contacted with the scavenger compositions in bulk sorption contacting vessels according to the invention.

Tom, Glenn M. (New Milford, CT); McManus, James V. (Danbury, CT); Luxon, Bruce A. (Stamford, CT)



Universality in Similarity Renormalization Group Evolved Potential Matrix Elements and T-Matrix Equivalence  

E-print Network

We examine how the universality of two-nucleon interactions evolved using similarity renormalization group (SRG) transformations correlates with T-matrix equivalence, with the ultimate goal of gaining insight into universality for three-nucleon forces. With sufficient running of the SRG flow equations, the low-energy matrix elements of different realistic potentials evolve to a universal form. Because these potentials are fit to low-energy data, they are (approximately) phase equivalent only up to a certain energy, and we find universality in evolved potentials up to the corresponding momentum. More generally we find universality in local energy regions, reflecting a local decoupling by the SRG. The further requirements for universality in evolved potential matrix elements are explored using two simple alternative potentials. We see evidence that in addition to predicting the same observables, common long-range potentials (i.e., explicit pion physics) is required for universality in the potential matrix elements after SRG flow. In agreement with observations made previously for Vlowk evolution, regions of universal potential matrix elements are restricted to where half-on-shell T-matrix equivalence holds.

B. Dainton; R. J. Furnstahl; R. J. Perry



Helium production in pure elements, isotopes, and alloy steels by 14. 8MeV neutrons  

Microsoft Academic Search

The results of an extensive series of total helium production cross-section measurements for incident neutrons in the 14- to 15-MeV energy region are presented, and an experimental data base for the prediction of helium generation in candidate fusion reactor materials is provided. The measurements were made by isotope-dilution gas mass spectrometry. They include the pure elements Be, B, C, O,

D. W. Kneff; B. M. Oliver; H. Farrar; L. R. Greenwood



Determination of copper, scandium, molybdenum, tin, lead, and iron group elements in lunar surface materials  

NASA Technical Reports Server (NTRS)

Distribution regularities of copper, scandium, molybdenum, tin, lead, and iron group elements were investigated in basaltoid rocks of lunar and terrestrial origin. Samples of various regolith zones taken in the area of the Sea of Fertility were analyzed, along with samples of basic and ultrabasic rocks of the East African Rift for their content of the trace admixtures listed. Data obtained on the abundance of copper, scandium, molybdenum, tin, lead, cobalt, nickel, chromium, and vanadium in Luna 16 lunar surface material were compared with the abundance of these elements in samples of lunar rocks returned by Apollo 11, Apollo 12, and Apollo 14, with the exception of scandium; its content in the latter samples was considerably higher.

Pavlenko, L. I.; Simonova, L. V.; Karyakin, A. V.



Variation of electron-phonon coupling in group IV elemental semiconductors  

NASA Astrophysics Data System (ADS)

Electron-phonon (e-ph) coupling determines the transfer of energy from hot electrons to the lattice, resulting in the heating of devices. In the current treatments, the e-ph coupling is determined within the long-wavelength phonon approximation. In this work, we consider the e-ph coupling and its variation over the entire Brillouin zone (BZ). The electronic structure and the full phonon dispersion are evaluated with the phonon dispersion calculated using the density functional perturbation theory (DFPT). The e-ph coupling is evaluated using maximally localized Wannier functions and generalized Fourier interpolation to generate e-ph matrix elements on arbitrary grids. Examples of specific initial electron momentum both in the valence and in the conduction bands are presented, together with the variation of the e-ph coupling over the entire BZ associated with the specific initial carrier momenta. We observe variations of up to about 400meV in Diamond and 50-100meV in Silicon and Germanium for the evaluated e-ph matrix element. We comment on the consequence of this variation on the carrier lifetimes in these materials.

Tandon, Nandan; Pugsley, Lisa; Ram-Mohan, L. R.



The Origin and Distribution of Heavy Elements in the CD Groups MKW 4 and AWM 4  

NASA Technical Reports Server (NTRS)

At this point, data for MKW4 have been received and those for AWM4 are still awaited. The MKW4 data have been fully analyzed and a complete manuscript is available and in final review by co-authors before submission for refereed publication. The following is a summary of our principal findings: We examined the distribution and properties of the hot gas which makes up the group halo. The inner halo shows some signs of structure, with circular or elliptical beta-models providing a poor fit to the surface brightness profile. This may be evidence of large-scale motion in the inner halo, but we do not find evidence of sharp fronts or edges in the emission. The temperature of the halo declines in the core, with deprojected spectral fits showing a central temperature of approximately 1.3keV compared to approximately 3keV at 250 arcsec. However, cooling flow models provide poor fits to the inner regions of the group and the estimated cooling time of the gas is long except within the central dominant galaxy, NGC4073. Abundance profiles show a sharp increase in the core of the group. We conclude that MKW4 is a fairly relaxed group, which has developed a strong central temperature gradient but not a large-scale cooling flow.

Vrtilek, Jan; Mushotzky, Richard (Technical Monitor)



Mobile elements and chromosomal evolution in the virilis group of Drosophila  

PubMed Central

Species of the virilis group of Drosophila differ by multiple inversions and chromosome fusions that probably accompanied, or led to, speciation. Drosophila virilis has the primitive karyotype for the group, and natural populations are exceptional in having no chromosomal polymorphisms. We report that the genomic locations of Penelope and Ulysses transposons are nonrandomly distributed in 12 strains of D. virilis. Furthermore, Penelope and Ulysses insertion sites in D. virilis show a statistically significant association with the breakpoints of inversions found in other species of the virilis group. Sixteen newly induced chromosomal rearrangements were isolated from the progeny of D. virilis hybrid dysgenic crosses, including 12 inversions, 2 translocations, and 2 deletions. Penelope and Ulysses were associated with the breakpoints of over half of these new rearrangements. Many rearrangement breakpoints also coincide with the chromosomal locations of Penelope and Ulysses insertions in the parental strains and with breakpoints of inversions previously established for other species of the group. Analysis of homologous sequences from D. virilis and Drosophila lummei indicated that Penelope insertion sites were closely, but not identically, located at the nucleotide sequence level. Overall, these results indicate that Penelope and Ulysses insert in a limited number of genomic locations and are consistent with the possibility that these elements play an important role in the evolution of the virilis species group. PMID:11016976

Evgen'ev, Michael B.; Zelentsova, Helena; Poluectova, Helena; Lyozin, George T.; Veleikodvorskaja, Vera; Pyatkov, K. I.; Zhivotovsky, Lev A.; Kidwell, Margaret G.



QuickGuide:TableofContents Page1 (v.2.AY_08032012) Completing Elements of the Proposal Development Document  

E-print Network

QuickGuide:TableofContents Page1 (v.2.AY_08032012) Completing Elements of the Proposal Development 8. View, Edit, and Submit a Proposal that has been Returned to You Table of Contents #12;QuickGuide:TableofContents Page1 (v.2.AY_08032012) #12;Quick Guide: Start and Save New Proposal Page 1 (v.3.AY 06282012) Initiate

Loudon, Catherine


The multivariate Charlier polynomials as matrix elements of the Euclidean group representation on oscillator states  

NASA Astrophysics Data System (ADS)

A family of multivariate orthogonal polynomials generalizing the standard (univariate) Charlier polynomials is shown to arise in the matrix elements of the unitary representation of the Euclidean group E(d) on oscillator states. These polynomials in d discrete variables are orthogonal on the product of d Poisson distributions. The accent is put on the d = 2 case and the group theoretical setting is used to obtain the main properties of the polynomials: orthogonality and recurrence relations, difference equation, raising/lowering relations, generating function, hypergeometric and integral representations and explicit expression in terms of standard Charlier and Krawtchouk polynomials. The approach is seen to extend straightforwardly to an arbitrary number of variables. The contraction of SO(3) to E(2) is used to show that the bivariate Charlier polynomials correspond to a limit of the bivariate Krawtchouk polynomials.

Genest, Vincent X.; Miki, Hiroshi; Vinet, Luc; Zhedanov, Alexei



Prospects of measuring the CKM matrix element |V| at the LHC  

NASA Astrophysics Data System (ADS)

We study the prospects of measuring the CKM matrix element |V| at the LHC with the top quarks produced in the processes pp?ttbarX and pp?t/tbarX, and the subsequent decays t?Ws and tbar?Wsbar. To reduce the jet activity in top quark decays, we insist on tagging the W leptonically, W??? ( ?=e,?,?), and analyse the anticipated jet profiles in the signal process t?Ws and the dominant background from the decay t?Wb. To that end, we analyse the V0 ( K and ?) distributions in the s- and b-quark jets concentrating on the energy and transverse momentum distributions of these particles. The V0s emanating from the t?Wb branch have displaced decay vertexes from the interaction point due to the weak decays b?c?s and the b-quark jets are rich in charged leptons. Hence, the absence of secondary vertexes and of the energetic charged leptons in the jet provide additional ( b-jet vs. s-jet) discrimination in top quark decays. These distributions are used to train a boosted decision tree (BDT), a technique used successfully in measuring the CKM matrix element |V| in single top production at the Tevatron. Using the BDT classifier, and a variant of it called BDTD, which makes use of decorrelated variables, we calculate the BDT(D)-response functions corresponding to the signal ( t?Ws) and background ( t?Wb). Detailed simulations undertaken by us with the Monte Carlo generator PYTHIA are used to estimate the background rejection versus signal efficiency for three representative LHC energies ?{s}=7 TeV, 10 TeV and 14 TeV, of which only the analysis for the ?{s}=14 TeV case is shown in detail. We argue that a benchmark with 10% accuracy for the signal ( t?Ws) at a background ( t?Wb) rejection by a factor 10 3 (required due to the anticipated value of the ratio |/|?1.6×10) can be achieved at the LHC@14 TeV with an integrated luminosity of 10 fb -1.

Ali, Ahmed; Barreiro, Fernando; Lagouri, Theodota



Analyses of platinum group elements in mosses as indicators of road traffic emissions in Austria  

NASA Astrophysics Data System (ADS)

The concentrations of platinum group elements (PGE; platinum, palladium, rhodium) and 17 other elements in mosses growing at 32 sampling sites along 12 roads in Austria were analysed. The study included passive monitoring of naturally growing mosses with an experimental design using mosses samples exposed in a tunnel experiment. PGEs (Pt, Pd, Rh) were analysed by ICP-MS (ELAN DRC II, Perkin Elmer SCIEX) according to EN ISO 17294-2 Tl.29. Mean concentrations of PGEs in five moss species were: Pt 7.07±9.97, Pd 2.8±5.2 und Rh 0.6±0.8 ng g -1 dry weight. This is comparable to data derived from measurements of gasoline autocatalyst emissions or airborne particles (<10 ?m). Compared to soils and road dust along highways, concentrations in mosses were lower by a factor of ten, compared to grasses they were comparable or somewhat higher. The ratios between the various PGEs were calculated as follows (mean values): Pt/Pd 7.9±10.2, Pt/Rh 12.6±8.3 and Pd/Rh 3.7±2.2. The number of light duty vehicles (<3.5 t) and the distance from the road were the main influential factors for PGE concentrations. Especially strong correlations could be found between Pt and Sb, Cu, Zn, and Cd (in decreasing order), which are all elements derived mainly from road traffic emissions. Cluster analysis (Partioning Around Medoids Method) separated elements derived mainly from soil dust (Ca, Al). An analysis of spatial deposition patterns of PGEs showed a reciprocal decrease of concentrations with increasing distance from the road, reaching background values at distances between 10 and 200 m, sometimes even more, but outside the spatial range of our investigation.

Zechmeister, Harald G.; Hagendorfer, Harald; Hohenwallner, Daniela; Hanus-Illnar, Andrea; Riss, Alarich


Trans-iron group elements in hot helium-rich white dwarfs  

NASA Astrophysics Data System (ADS)

Our recent detection of twelve trans-iron group elements (Z=30-56) in the hot helium-rich white dwarf (i.e. spectral type DO) RE0503-289 is a unique discovery. This phenomenon was never observed before in any white dwarf. Abundance analyses hitherto performed for five species (Zn, Ge, Kr, Xe, Ba) reveal values between 155 and 23000 times solar. There are reasons to believe that these extreme overabundances are connected to the evolutionary history of the DO white dwarfs. They are the outcome of a late helium-shell flash that consumes all hydrogen in the stellar envelope and at the same time dredges up helium-rich intershell matter that is enriched with s-process elements. These elements were synthesised in the preceding AGB phase of the evolution. We argue that if RE0503-289 is a typical representative of the DO white dwarfs, then all DOs with similar effective temperature should also show these extraordinary chemical diversity and overabundances. In order to prove this hypothesis, we want to obtain FUV spectra of two other hot DO white dwarfs plus a representative of the PG1159 stars, which are thought to be immediate progenitors of DO white dwarfs. If all three targets show the same heavy-metal abundance pattern, then these objects hold the promise that their metal abundances can be used to constrain AGB star nucleosynthesis. If otherwise RE0503-289 remains a unique object, then an alternative evolutionary scenario (binary WD merger) is probably responsible for its extreme element abundances.

Werner, Klaus



Coronal Element Abundances in the G8 V Star XI Boo A  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of a deep EUVE exposure (270 ks) of the G8 V star xi Boo A. We evaluate electron densities from line ratios in Fe X, Fe XII, Fe XIII, and Fe XIV, and use the intensities of lines from ions Fe IX - XXII to establish the emission measure distribution. We also observe and measure emission in lines from Ne VII, Mg VII - IX, Si VII, VIII, X, XII, S XII - XIV, Ar XV, XVI, Ca XIV - XVII, and Ni XVII, XVIII, from which we derive relative abundances in the corona of xi Boo A. We find very strong evidence for the FIP (First Ionization Potential) effect, in that the abundances of low FIP elements Mg, Si, Ca, Fe, and Ni appear to be enhanced by a factor of about 4 over those of the high FIP elements S and Ar, relative to their photospheric values. Thus xi Boo A joins alpha Cen B (K2 V) and possibly epsilon Eri (K2 V) in showing similar coronal abundance anomalies to those observed in the Sun, in contrast to Procyon (F5 IV) whose corona appears to have similar composition to its photosphere.

Laming, J. Martin; Drake, Jeremy J.



An experimental study of mass transfer of platinum-group elements, gold, nickel and copper in sulfur-dominated vapor  

E-print Network

An experimental study of mass transfer of platinum-group elements, gold, nickel and copper-solution (Mss) in the donor, Cu is transferred more than Ni. Gold is transferred 10 times more efficiently than complexes. In contrast, Cu and Au show no correlation with f S2 suggesting that these elements

Long, Bernard


Rhenium and platinum group element abundances correlated with mantle source components in Hawaiian picrites: sulphides in the plume  

Microsoft Academic Search

Core addition and crustal recycling models that seek to explain the radiogenic Os isotopic compositions of primitive Hawaii tholeiites predict distinctive geochemical consequences for chalcophile and siderophile element abundances in the mantle plume. To test these models and to improve our understanding of compositional variability in the Hawaiian plume, the platinum group element (PGE) and Re contents of primitive shield

V. C. Bennett; M. D. Norman; M. O. Garcia



Enzymatic properties of rat group IIA and V phospholipases A 2 compared  

Microsoft Academic Search

Group IIA and V phospholipases A2 (PLA2s) are known to play a role in inflammatory responses. We have constructed a bacterial expression vector for rat group IIA and V PLA2s, over-expressed, folded and purified the proteins with the aim to study and compare the properties of the enzymes in detail. For zwitterionic phospholipid micelles, both enzymes display optimum activity at

Marcel J. W. Janssen; Leendert Vermeulen; Hester A. Van der Helm; Anton J. Aarsman; Arend J. Slotboom; Maarten R. Egmond



Implementation of Hybrid V-Cycle Multilevel Methods for Mixed Finite Element Systems with Penalty  

NASA Technical Reports Server (NTRS)

The goal of this paper is the implementation of hybrid V-cycle hierarchical multilevel methods for the indefinite discrete systems which arise when a mixed finite element approximation is used to solve elliptic boundary value problems. By introducing a penalty parameter, the perturbed indefinite system can be reduced to a symmetric positive definite system containing the small penalty parameter for the velocity unknown alone. We stabilize the hierarchical spatial decomposition approach proposed by Cai, Goldstein, and Pasciak for the reduced system. We demonstrate that the relative condition number of the preconditioner is bounded uniformly with respect to the penalty parameter, the number of levels and possible jumps of the coefficients as long as they occur only across the edges of the coarsest elements.

Lai, Chen-Yao G.



Accumulation of platinum group elements by the marine gastropod Littorina littorea.  


The accumulation and trophic transfer of the platinum group elements (PGE): Rh, Pd and Pt; have been studied in short-term (5 day) exposures conducted in aquaria containing the marine macroalga, Ulva lactuca, and/or the grazing mollusc, Littorina littorea. Metals added to sea water (to concentrations of 20 ?g L?¹) were taken up by U. lactuca in the order Rh, Pt > Pd and by L. littorea in the order Pd ? Pt ? Rh, with greatest metal accumulation in the latter generally occurring in the visceral complex and kidney. When fed contaminated alga, accumulation of Rh and Pd by L. littorea, relative to total available metal, increased by an order of magnitude, while accumulation of Pt was not readily detected. We conclude that the diet is the most important vector for accumulation of Rh and Pd, while accumulation of Pt appears to proceed mainly from the aqueous phase. PMID:21237543

Mulholland, Rachel; Turner, Andrew



Ab initio effective core potentials for molecular calculations. Potentials for main group elements Na to Bi  

SciTech Connect

A consistent set of ab initio effective core potentials (ECP) has been generated for the main group elements from Na to Bi using the procedure originally developed by Kahn. The ECP's are derived from all-electron numerical Hartree--Fock atomic wave functions and fit to analytical representations for use in molecular calculations. For Rb to Bi the ECP's are generated from the relativistic Hartree--Fock atomic wave functions of Cowan which incorporate the Darwin and mass--velocity terms. Energy-optimized valence basis sets of (3s3p) primitive Gaussians are presented for use with the ECP's. Comparisons between all-electron and valence-electron ECP calculations are presented for NaF, NaCl, Cl/sub 2/, Cl/sub 2//sup -/, Br/sub 2/, Br/sub 2//sup -/, and Xe/sub 2//sup +/. The results show that the average errors introduced by the ECP's are generally only a few percent.

Wadt, W.R.; Hay, P.J.



Divisions i and III / Working Group: Cartographic Coordinates and Rotational Elements  

NASA Astrophysics Data System (ADS)

As in the past, the primary activity of the IAU Working Group on Cartographic Coordinates and Rotational Elements has been to prepare and publish a triennial (``2009'') report containing current recommendations for models for Solar System bodies (Archinal et al. (2011a)). The authors are B. A. Archinal, M. F. A'Hearn, E. Bowell, A. Conrad, G. J. Consolmagno, R. Courtin, T. Fukushima, D. Hestroffer, J. L. Hilton, G. A. Krasinsky, G. Neumann, J. Oberst, P. K. Seidelmann, P. Stooke, D. J. Tholen, P. C. Thomas, and I. P. Williams. An erratum to the ``2006'' and ``2009'' reports has also been published (Archinal et al. (2011b)). Below we briefly summarize the contents of the 2009 report, a plan to consider requests for new recommendations more often than every three years, three general recommendations by the WG to the planetary community, other WG activities, and plans for our next report.

Archinal, Brent A.; Seidelmann, P. Kenneth; A'Hearn, Michael F.; Conrad, Albert R.; Consolmagno, Guy J.; Courtin, Régis; Fukushima, Toshio; Hestroffer, Daniel; Hilton, James L.; Neumann, Gregory A.; Oberst, Jürgen; Stooke, Philip J.; Tholen, David J.; Thomas, Peter C.; Williams, Iwan P.



Effects of Cu2+ on morphological structure, functional groups, and elemental composition of aerobic granular sludge.  


Aerobic granular sludge (AGS) is shaped by the self-immobilization of microorganisms. In this study, AGS was cultivated successively in a column sequencing batch reactor (SBR) with glucose and sodium acetate as the carbon sources. The shock-loading effects of varying the Cu2+ concentration (0.0, 1.0, 3.0, 5.0, or 10.0 mg/L) on the characteristics of aerobic granules were studied. The results show that Cu2+ has a toxic effect on the aerobic granules. Although the aerobic granules became increasingly loose as the Cu2+ concentration increased from 1.0 to 5.0 mg/L, their structural integrity was largely maintained. However, the aerobic granules disintegrated and their skeletons consisting of internal filamentous bacteria were exposed at the Cu2+ concentration of 10.0mg/L. The functional groups -NH2, -OH, -COOH, and C-N reacted with Cu2+. Ca, Fe, and P were the major trace elements observed in the AGS. With an increase in the Cu2+ concentration from 0.0 to 10.0 mg/L, the weight percentages of the essential elements Fe, Ca, Na, and K in the granules decreased from 23.98%, 24.64%, 3.86%, and 3.87% to 14.90%, 13.93%, 0%, and 0%, respectively, whereas the weight percentage of copper increased correspondingly from 0% to 35.43%. Cu2+ was exchanged with the essential metals and chelated by the nitrogen-containing functional groups (-NH2 or C-N) of the protein. These effects influenced the structural stability of the sludge. PMID:23530333

Zheng, Xiao-Ying; Wang, Xing-Nan; Huang, Xi; Chen, Qing; Chen, Wei; He, Yu-Jie



arXiv:0803.3824v1[math.NA]27Mar2008 Convergence rates for adaptive finite elements  

E-print Network

arXiv:0803.3824v1[math.NA]27Mar2008 Convergence rates for adaptive finite elements Fernando D, 2008 Abstract In this article we prove that it is possible to construct, using newest- vertex bisection). As a consequence, the meshes turn out to be quasi-optimal, and convergence rates for adaptive finite element meth

Morin, Pedro


33 CFR 155.1052 - Response plan development and evaluation criteria for vessels carrying group V petroleum oil as a...  

...criteria for vessels carrying group V petroleum oil as a primary cargo. 155.1052...criteria for vessels carrying group V petroleum oil as a primary cargo. (a) Owners...operators of vessels that carry group V petroleum oil as a primary cargo must provide...



The Gestalt Principles of Similarity and Proximity Apply to Both the Haptic and Visual Grouping of Elements  

Microsoft Academic Search

When designing multi-sensory displays it is necessary to consider human perceptual capabilities and understand how people find patterns and how they organise individual elements into structures and groups. Gestalt theory, originally described in 1910, attempts to explain the way people perceive and recognise patterns. The early studies of Gestalt principles of grouping were predominantly concerned with visual perception, although more

Dempsey Chang; Keith V. Nesbitt; Kevin Wilkins


Chemical evolution of neutron capture elements in our Galaxy and in the dwarf spheroidal galaxies of the Local Group  

E-print Network

By adopting a chemical evolution model for the Milky Way already reproducing the evolution of several chemical elements, we compare our theoretical results with accurate and new stellar data of neutron capture elements and we are able to impose strong constraints on the nucleosynthesis of the studied elements. We can suggest the stellar sites of production for each element. In particular, the r-process component of each element (if any) is produced in the mass range from 10 to 30 Msun, whereas the s-process component arises from stars in the range from 1 to 3 Msun. Using the same chemical evolution model, extended to different galactocentric distances, we obtain results on the radial gradients of the Milky Way. We compare the results of the model not only for the neutron capture elements but also for alpha-elements and iron peak elements with new data of Cepheids stars. We give a possible explanation to the considerable scatter of neutron capture elements observed in low metallicity stars in the solar vicinity, compared to the small star to star scatter observed for the alpha-elements. In fact, we have developed a stochastic chemical evolution model, in which the main assumption is a random formation of new stars, subject to the condition that the cumulative mass distribution follows a given initial mass function. With our model we are able to reproduce the different features of neutron capture elements and alpha-elements. Finally, we test the prescriptions for neutron capture elements also for the dwarf spheroidal galaxies of the Local Group. We predict that the chemical evolution of these elements in dwarf spheroidal galaxies is different from the evolution in the solar vicinity and indicates that dwarf spheroidal galaxies (we see nowadays) cannot be the building blocks of our Galaxy.

Gabriele Cescutti



Development of metallographic preparation techniques for group IVA and VA elements  

SciTech Connect

Existing metallographic preparation techniques for Group IVA/VA (e.g. V, Ti, Ta, Hf, Nb, Zr) materials do not reveal all microstructural features inherent to the process history. As a result, new techniques have been developed and compared to existing procedures. For example, in pure tantalum, the new procedure exposes a substructure that is not evident using previously published techniques. In niobium, better grain boundary delineation is possible with the new process. Similar results are evident for titanium, zirconium, vanadium, and hafnium. The new preparation stage includes a chemical polish and etchant. The chemical polish was found to eliminate problems associated with the mechanical polish. Specifically, the chemical polish removes the worked surface and eliminates smearing. The etching stage serves to delineate the grain boundaries, and in some cases allows bright field as well as polarized or differential interference contrast (DIC) for optical examination. Finally, optical lighting conditions to enhance the observations available with the optimized procedure will be discussed.

Bingert, S. A. (Sherri A.); Abeln, T. G. (Terri G.); Thoma, D. J. (Dan J.); Cooley, J. C. (Jason C.); Hults, W. L. (William L.); Kelly, A. M. (Anna Marie)



Re-187-Os-187, Pt-190-Os-186 Isotopic and Highly Siderophile Element Systematics of Group IVA Irons  

NASA Technical Reports Server (NTRS)

We have recently completed Re-187-Os-187 and Pt-190-Os-186 isotopic and elemental studies of the two largest magmatic iron meteorite groups, IIAB and IIIAB [1]. These studies revealed closed-system behavior of both isotopic systems, but complex trace element behavior for Re, Pt and Os in group IIIAB. Here we examine isotopic and trace elemental systematics of group IVA irons. The IVA irons are not as extensively fractionated as IIAB and IIIAB and their apparently less complex crystallization history may make for more robust interpretation of the relative partitioning behavior of Re, Pt and Os, as well as the other highly siderophile elements (HSE) measured here; Pd, Ru and Ir [e.g. 2]. An additional goal of our continuing research plan for iron meteorites is to assess the possibility of relating certain ungrouped irons with major groups via trace element modeling. Here, the isotopic and trace element systematics of the ungrouped irons Nedagolla and EET 83230 are compared with the IVA irons.

Walker, R. J.; McCoy, T. J.; Schulte, R. F.; McDonough, W. F.; Ash, R. D.



Measurements of total atomic attenuation cross sections of Tm, Yb, Lu, Hf, Ta, W, Re and Os Elements at 122keV and 136keV  

SciTech Connect

The aim of this study was to measure the total atomic attenuation cross sections ({sigma}t) in eighth elements (69{<=}Z{<=}76) at 122 keV and 136 keV. The experimental values of the cross sections were determined using the transmission geometry. Measurements have been performed using an annular source (Co-57) and Ultra-LEGe solid state detector with a resolution of 150 eV at 5.9 keV. Experimental results have been compared with theoretically calculated values and other available experimental results. Good agreement was observed among the experimental, theoretical and other experimental values.

Kaya, N.; Tirasoglu, E.; Apaydin, G.; Kobya, A. I. [Karadeniz Technical University, Faculty of Arts and Sciences, Department of Physics, Trabzon, 61080 (Turkey)



Coronal Element Abundances of the Post-Common Envelope Binary V471 Tauri with ASCA  

NASA Technical Reports Server (NTRS)

We report on ASCA observations of the coronally active companion star in the post-common envelope binary V471 Tau. While it would be prudent to check the following results with grating spectroscopy, we find that a single-temperature plasma model does not fit the data. Two temperature models with variable abundances indicate that Fe is underabundant compared to the Hyades photospheric mean, whereas, the high first ionization potential element Ne is overabundant. This is indicative of the inverse first ionization effect, believed to result from the fractionation of ionized material by the magnetic field in the upper atmosphere of the star. Evolutionary calculations indicate that there should be no peculiar abundances on the companion star resulting from the common envelope epoch. Indeed, we find no evidence for peculiar abundances, although uncertainties are high.

Still, Martin; Hussain, Gaitee; White, Nicholas E. (Technical Monitor)



Study on 12kV outdoor vacuum switch with replaceable HRC element drop out fuse  

SciTech Connect

A new type of vacuum interrupter for 12kV outdoor vacuum switch was experimentally studied, the envelope of which was made of porcelain with petticoat flange for outdoor insulation. In order to produce an axial magnetic field and improve the capacity of transfer current in the vacuum interrupter, an iron plate of horse-shoe construction ingeniously designed was chosen as an electrode. The drop-out fuse with replaceable sand-filled HRC element in series with the vacuum switch is a new conception of design to increase breaking capacity. However, it is a vacuum switch of newly designed to form {open_quotes}a vacuum switch and drop-out type fuse combination{close_quotes}.

Wang Jiimei [Xi` an Jiaotong Univ. (China)



Platinum group elements in raptor eggs, faeces, blood, liver and kidney.  


The increased use of platinum group elements (PGEs) in automobile catalysts and their emission into the environment has led to a concern over environmental and particularly biological accumulation. Specimens of samples from raptors are useful for the investigation of the impact of PGEs because these birds are found in both urban and rural environments and are invariably at the top of the food chain. Platinum (Pt), palladium (Pd) and rhodium (Rh) concentrations were determined by quadrupole Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in eggs of the sparrowhawk (Accipiter nisus) and the peregrine falcon (Falco peregrinus), and in blood, liver and kidney of the peregrine falcon, while only Pt was determined in faeces of the peregrine falcon and the gyrfalcon (Falco rusticolus). PGE concentrations were higher in blood compared to both faeces and eggs, while liver and kidney concentrations were not elevated indicating no bioaccumulation through metallothionein pathways. A significant spatial trend could only be established for Pt in faeces. The general lack of a spatial trend is probably due to the widespread distribution of automobiles and the long-range transport of nanoparticles containing PGEs, and because birds migrate and forage over large areas. No significant temporal trend could be established. Higher relative concentrations of Pd, followed by Rh and Pt, indicate a mobility gradient of Pd>Rh>Pt. PMID:15504501

Ek, Kristine H; Rauch, Sebastien; Morrison, Gregory M; Lindberg, Peter



Platinum group element incorporation into human bones resulting from increased anthropogenic utilization  

NASA Astrophysics Data System (ADS)

Platinum group elements (including Pt, Pd, Ru, Rh, Os, Ir) are rare precious metals that occur at exceedingly low concentrations in the Earth’s crust (~0.02-0.5 ng/g). Utilization of PGEs in the catalytic converter of automobiles, medical treatments, electronics, and as a catalyst, has rapidly increased since the early 20th century, leading to increased anthropogenic PGE emissions and consequently increasing concentrations in the environment. Recent reports indicate that environmental PGE concentrations are increasing in urban air, roadside soils, and aquatic environments (Rauch and Morrison, 2008). As a result, there is an increased potential for PGE uptake into the biosphere. To evaluate bio-incorporation of PGEs into the human body we use ICP-MS to analyze for PGE concentration in human bones. Human bone minerals serve as a reservoir for the majority of the body’s trace metals and provide a measure of PGE incorporation into the human body from various environmental sources. We compare PGE concentrations in femoral heads of 30 present-day modern humans to those in femurs of 10 humans exhumed from 18th and 19th century burial sites, whose metal exposures predate extensive anthropogenic use of PGEs.

Darrah, T. H.; Hannigan, R. E.; Campbell, E.; Prutsman-Pfeiffer, J.



[Pollution characteristics of platinum group elements in road dust in central urban area of Beijing].  


In order to survey platinum group elements (PGEs) contamination in central urban area of Beijing, dust samples were collected from the second ring road in December 2009. The road samples were digested with aqua regia and separated and purified with cation exchange resin, and the resulting solutions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the concentrations of Pd, Pt and Rh in road dust ranged from 17.40-458.75 ng x g(-1) (126.66 ng x g(-1)), 10.04-182.89 ng x g(-1) (65.25 ng x g(-1)), 4.00-68.04 ng x g(-1) (22.67 ng x g(-1)) respectively. In comparison with international cities, Pd and Rh concentrations in Beijing road dust were middle level and Pt concentration was lower. Pd concentration was rapidly increased in recent years. The concentrations of PGEs in four locations of the second ring road were arranged in the following order: West approximately East > North > South, which were controlled with the traffic intensity. Size partitioning indicated that the 0.125-0.25 mm fraction had the higher PGEs concentrations than other fractions and the < 0.063 mm fraction had the lower PGEs concentration. These data suggest that autocatalyst PGEs flux estimates into the environment will be significantly underestimated if only a fine grain size fraction (< 0.063 mm) is analyzed. PMID:21634172

Xu, Ling-Ling; Gao, Bo; Lu, Jin; Zhou, Huai-Dong; Hao, Hong; Wang, Xiao-Jun



Group velocity of the light pulse in an open V-type system  

NASA Astrophysics Data System (ADS)

We investigate the group velocity of the probe light pulse in an open V-type system with spontaneously generated coherence. We find that, not only varying the relative phase between the probe and driving pulses can but varying the atomic exit rate or incoherent pumping rate also can manipulate dramatically the group velocity, even make the pulse propagation switching from subluminal to superluminal; the subliminal propagation can be companied with gain or absorption, but the superluminal propagation is always companied with absorption.

Li, Jingjuan; Fan, Xijun; Tian, Shufen; Liu, Chengpu; Gong, Shangqing; Xu, Zhizhan



Platinum-group elements: quantification in collected exhaust fumes and studies of catalyst surfaces.  


Automotive catalytic converters, in which Pt, Pd and Rh (platinum-group elements; PGEs) are the active components for eliminating several noxious components from exhaust fumes, have become the main source of environmental urban pollution by PGEs. This work reports on the catalyst morphology through changes in catalyst surface by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and laser-induced breakdown spectrometry (LIBS) from fresh to aged catalytic converters. The distribution of these elements in the fresh catalysts analysed (Pt-Pd-Rh gasoline catalyst) is not uniform and occurs mainly in a longitudinal direction. This heterogeneity seems to be greater for Pt and Pd. PGEs released by the catalysts, fresh and aged 30,000 km, were studied in parallel. Whole raw exhaust fumes from four catalysts of three different types were also examined. Two of these were gasoline catalysts (Pt-Pd Rh and Pd-Rh) and the other two were diesel catalysts (Pt). Samples were collected following the 91,441 EUDC driving cycle for light-duty vehicle testing. The results show that at 0 km the samples collected first have the highest content of particulate PGEs and although the general tendency is for the release to decrease with increasing number of samples taken, exceptions are frequent. At 30,000 km the released PGEs in gasoline and diesel catalysts decreased significantly. For fresh gasoline catalysts the mean of the total amount released was approximately 100, 250 and 50 ng km(-1) for Pt, Pd and Rh, respectively. In diesel catalysts the Pt release varied in the range 400-800 ng km-1. After ageing the catalysts up to 30,000 km, the gasoline catalysts released amounts of Pt between 6 and 8 ng km(-1), Pd between 12 and 16 ng km(-1) and Rh between 3 and 12 ng km(-1). In diesel catalysts the Pt release varied in the range 108-150 ng km(-1). The soluble portion of PGEs in the HNO3 collector solution represented less than 5% of the total amount for fresh catalysts. For 30,000 km the total amount of soluble PGEs released was similar or slightly higher than for 0 km. PMID:10943898

Palacios, M A; Gómez, M M; Moldovan, M; Morrison, G; Rauch, S; Mcleod, C; Ma, R; Laserna, J; Lucena, P; Caroli, S; Alimonti, A; Petrucci, F; Bocca, B; Schramel, P; Lustig, S; Zischka, M; Wass, U; Stenbom, B; Luna, M; Saenz, J C; Santamaría, J; Torrens, J M



Should an Obsessive-Compulsive Spectrum Grouping of Disorders Be Included in DSM-V?  

PubMed Central

The obsessive-compulsive (OC) spectrum has been discussed in the literature for two decades. Proponents of this concept propose that certain disorders characterized by repetitive thoughts and/or behaviors are related to obsessive-compulsive disorder (OCD), and suggest that such disorders be grouped together in the same category (i.e., grouping, or “chapter”) in DSM. This paper addresses this topic and presents options and preliminary recommendations to be considered for DSM-V. The paper builds upon and extends prior reviews of this topic that were prepared for and discussed at a DSM-V Research Planning Conference on Obsessive-Compulsive Spectrum Disorders held in 2006. Our preliminary recommendation is that an OC-spectrum grouping of disorders be included in DSM-V. Furthermore, we preliminarily recommend that consideration be given to including this group of disorders within a larger supraordinate category of “Anxiety and Obsessive-Compulsive Spectrum Disorders.” These preliminary recommendations must be evaluated in light of recommendations for, and constraints upon, the overall structure of DSM-V. PMID:20533367

Phillips, Katharine A.; Stein, Dan J.; Rauch, Scott; Hollander, Eric; Fallon, Brian A.; Barsky, Arthur; Fineberg, Naomi; Mataix-Cols, David; Ferrao, Ygor Arzeno; Saxena, Sanjaya; Wilhelm, Sabine; Kelly, Megan M.; Clark, Lee Anna; Pinto, Anthony; Bienvenu, O. Joseph; Farrow, Joanne; Leckman, James



I. ASCRC General Education Form Group V. Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V. Literary and Artistic Studies Dept/Program English American Literature. It studies the development of a unique American aesthetic in a literary renaissance. Through the study of a variety of literary terms, students gain tools literary analysis. Students

Vonessen, Nikolaus


I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V Literary and Artistic Studies Dept/Program Environmental Studies Course # 305L Course Title The Environmental Vision Prerequisite None Credits 3 II. Endorsement works and authors in American literary writing about nature, environment, natural history, and place

Vonessen, Nikolaus


I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V Literary and Artistic Studies Dept/Program English, and political contents of the authors and works we study, as well as on literary form. IV. Criteria: Briefly of the literary works we study. In addition, these courses provide mechanisms for students 1) to receive

Vonessen, Nikolaus


I. ASCRC General Education Form Group V: Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary and Artistic Studies Dept/Program English in the English literary tradition, Geoffrey Chaucer. Students read biographical material on Chaucer, as well is inherently interdisciplinary, with major units on history, manuscript studies, and art history. It also

Vonessen, Nikolaus


I. ASCRC General Education Form Group V: Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary and Artistic Studies Dept/Program English/Literature Course # ENLT 349 Course Title Studies in Medieval Literature Prerequisite None Credits 3 II. Endorsement in that many of the literary and cultural institutions that evolved to support the growth of literary culture

Vonessen, Nikolaus


I. ASCRC General Education Form Group V: Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary and Artistic Studies Dept/Program English/Literature Course # ENLT 349L Course Title Studies in Medieval Literature Prerequisite None Credits 3 II in that many of the literary and cultural institutions that evolved to support the growth of literary culture

Vonessen, Nikolaus


I. ASCRC General Education Form Group V. Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V. Literary and Artistic Studies Dept/Program English Course, and postmodernism. American Literature Since 1865 also involves the advanced study of literary terms and concepts literary studies by giving them a detailed background in important writers and texts, in literary history

Vonessen, Nikolaus


I. ASCRC General Education Form Group V: Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V: Literary and Artistic Studies Dept/Program English will be introduced to major conceptual and theoretical problems relevant to the study of literary history that you first major literary texts, and the 17th century, when citizens of a modern British state published

Vonessen, Nikolaus


I. ASCRC General Education Form Group V. Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V. Literary and Artistic Studies Dept/Program English Outcome Criterion listed on the syllabus: 2) Recognition of key historical and literary issues of Montana. Relevant Outcome Criterion listed on syllabus: 3) Recognition of different methods -- literary

Vonessen, Nikolaus


I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

I. ASCRC General Education Form Group V Literary and Artistic Studies Dept/Program English, and literary transformations taking place in the texts we study from each period. Thus, for example, in our purpose is to improve students' ability to write clearly, critically, and imaginatively about literary

Vonessen, Nikolaus


Group V Secretory Phospholipase A2 Modulates Phagosome Maturation and Regulates the Innate Immune Response  

E-print Network

Response against Candida albicans1 Barbara Balestrieri,*2 Akiko Maekawa,* Wei Xing,* Michael H. Gelb lacking group V sPLA2 had delays in phagocy- tosis, phagosome maturation, and killing of Candida albicans and TLR2 (10). Candida albicans is an opportunistic pathogen that shares many signaling events

Gelb, Michael


2003 NaturePublishing Group R E V I E W S  

E-print Network

© 2003 NaturePublishing Group R E V I E W S NATURE REVIEWS | GENETICS VOLUME 4 | JUNE 2003 | 457 in observ- ing the dynamics of evolutionary change more directly. Indeed,Charles Darwin remarked in 1859 Científicas, 46022 Valencia,Spain. Department of Microbiology and Molecular Genetics,Michigan State

Elena, Santiago F.


I. ASCRC General Education Form Group V: Literary and Artistic Studies  

E-print Network

structure, capitalism, science, technology, religion, imperialism, gender) as they relate to literature; (2I. ASCRC General Education Form Group V: Literary and Artistic Studies Dept/Program English/Literature Course # ENLT 219L Course Title British Literature: Victorian to Contemporary Prerequisite None Credits O

Vonessen, Nikolaus


Layered V-B-O polyoxometalate nets linked by diethylenetriamine complexes with dangling amine groups.  


Two layered V-B-O contained polyoxometalate (POM) net structures, denoted as SUT-12 and SUT-13, are reported here. SUT-12 was synthesized by the boric acid flux method, and it represents the first 2D structure constructed from the V6B20 vanadoborate cluster. SUT-13 was synthesized by the hydrothermal method and constructed from V12B6P12 vanadium borophosphate clusters. In both structures, the vanadoborate or vanadium borophosphate clusters were linked through in situ formed Zn(DETA)2 or Cu(DETA)2 complexes. Surprisingly, for all DETA molecules in the two metal complexes, there is one dangling amine group when it is coordinated to the metal. The phenomenon of the dangling amine group feature is abnormal and the Cu(DETA)2 complexes in SUT-13 were taken as an example and studied by the density functional theory (DFT) calculations in order to understand this unusual feature. PMID:25182271

Chen, Hong; Zhang, Yunfeng; Yu, Zheng-Bao; Sun, Junliang



Sulfide saturation history of the Stillwater Complex, Montana: chemostratigraphic variation in platinum group elements  

NASA Astrophysics Data System (ADS)

A platinum group element (PGE) investigation of a 5.3 km-thick stratigraphic section of the Stillwater Complex, Montana was undertaken to refine and test a geochemical technique to explore for platiniferous horizons in layered mafic/ultramafic complexes. PGE, Au, major, and trace elements were determined in 92 samples from outcrops along traverses in the Chrome Mountain and Contact Mountain areas in the western part of the Stillwater Complex where the J-M reef occurs ˜1,460 m above the floor of the intrusion. A further 29 samples from a drill hole cored in the immediate vicinity of the J-M reef were analyzed to detail compositional variations directly above and below the J-M reef. Below the J-M reef, background concentrations of Pt (10 ppb) and Pd (7 ppb) are features of peridotites with intermediate S concentrations (mostly 100-200 ppm) and rocks from the Bronzitite, Norite I, and Gabbronorite I zones (mostly <100 ppm S). A sustained increase in S abundance commences at the J-M reef and continues to increase and peaks in the center of the 600 m-thick middle banded series. Over this same interval, Pt, Pd, and Au are initially elevated and then decrease in the order Pd > Pt > Au. Within the middle and upper banded series, S abundances fluctuate considerably, but exhibit an overall upward increase. The behavior of these elements records periodic sulfide saturation during deposition of the Peridotite zone, followed by crystallization under sulfide-undersaturated conditions until saturation is achieved at the base of the J-M reef. Following formation of the reef, sulfide-saturated conditions persisted throughout the deposition of most of the remaining Lower Layered Series. This resulted in a pronounced impoverishment in PGE abundance in the remaining magma, a condition that continued throughout deposition of the remainder of a succession, which is characterized by very low Pt (1.5 ppb) and Pd (0.7 ppb) abundances. Because only unmineralized rock was selected for study in the 5.3 km-thick section, the results provide an unbiased picture of the variation in background PGE levels during crystallization of the Stillwater Complex. In contrast, the variations in the drill core samples through the reef provide a detailed record of ore formation. Plots of Pt, Pd, Pd/S, and Pt + Pd as a function of stratigraphic height in the intrusion show that the location of the J-M reef is defined by an abrupt change in these concentrations and ratios. Although this is the most abrupt change, three other anomalies in PGE abundance and ratios are apparent in the profiles and coincide with known laterally extensive sub-economic sulfide concentrations above the J-M reef. The uppermost of these is the PGE-bearing Picket Pin sulfide horizon. The relative ease with which mineralized horizons can be pinpointed in these diagrams indicates that a similar approach could be used in exploration programs in other ultramafic/mafic intrusions. Our observations exclude the possibilities of either magma mixing within the Stillwater chamber or the fluxing of a volatile-rich fluid as the mechanisms responsible for the genesis of the J-M reef. Rather, our data indicate that the J-M reef formed from a parental magma that was strongly enriched in PGE; this magma likely formed at depth below the Stillwater magma chamber by the interaction of the parental magma with S-rich meta-sedimentary rocks, followed by the re-dissolution of these sulfides in the Stillwater magma.

Keays, Reid R.; Lightfoot, Peter C.; Hamlyn, Paul R.



Creep deformation and fracture of a Cr\\/Mo\\/V bolting steel containing selected trace-element additions  

Microsoft Academic Search

The article reports the creep behavior, at 565 °C, of 1Cr1Mo0.75V (Ti, B) (Durehete D1055) steel, in each of two grain sizes\\u000a and doped with individual trace elements such as P, As, and Sn, in comparison to a reference cast of the base material containing\\u000a 0.08 wt pct Ti. The addition of the trace elements P, As, or Sn (each

Z. Larouk; R. Pilkington



Platinum group elements in the feathers of raptors and their prey.  


Platinum (Pt), palladium (Pd), and rhodium (Rh) concentrations were determined in the feathers of three raptor species in Sweden, the sparrowhawk ( Accipiter nisus), the peregrine falcon ( Falco peregrinus), and the gyrfalcon ( Falco rusticolus), as well as the main prey of the sparrowhawk (the house sparrow, Passer domesticus) and the gyrfalcon (the willow grouse, Lagopus lagopus). The analysis of feathers from 1917-1999 revealed a clear temporal trend, with significantly higher Rh concentrations in sparrowhawk and peregrine falcon after 1986. There is evidence for increasing platinum group element (PGE) concentrations from 1917 to 1999 in peregrine falcon and sparrowhawk. This suggests that feathers reflect increased PGE concentrations in the environment over this time period. Mean concentrations of PGE in feathers of raptors after 1986 ranged from 0.3 to 1.8 ng x g(-1) for Pt, 0.6 to 2.1 ng x g(-1) for Pd (indicative values), and 0.1 to 0.6 ng x g(-1) for Rh. House sparrows in urban areas had significantly higher Pt and Pd concentrations than urban sparrowhawks. The higher Pd concentrations in relation to Pt and Rh may indicate the greater mobility of Pd in the environment. Although PGE concentrations are generally higher in birds living in urban areas, no significant spatial trend could be established. This is partly due to the widespread distribution of automobiles and partly because birds forage and integrate PGE exposure over large areas. Laser ablation analysis demonstrates that PGE contamination of feathers is predominantly external, consisting of small particles in the nanometer size range. Other indications of external contamination are that Pt and Pd levels are significantly higher in the vane than in the shaft and that PGE relative ratios (except Pd) reflect urban particles. PMID:11910463

Jensen, K H; Rauch, S; Morrison, G M; Lindberg, P



CLINICAL TRIALS OFFICE The principal charge of this focus group was to identify the key elements of a Clinical Trials  

E-print Network

CLINICAL TRIALS OFFICE The principal charge of this focus group was to identify the key elements of a Clinical Trials Office at the LSUHSC-NO Campus. We propose that the mission of the Clinical Trials Office. The Clinical Trials Office will function as a single point-of-contact for all aspects of clinical trials


Report of the IAU\\/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 2000  

Microsoft Academic Search

Every three years the IAU\\/IAG Working Group on cartographic coordinates and rotational elements of the planets and satellites revises tables giving the directions of the north poles of rotation and the prime meridians of the planets, satellites, and asteroids. Also presented are revised tables giving their sizes and shapes. Changes since the previous report are summarized in the Appendix.

V. K. Abalakin; M. Bursa; M. E. Davies; C. de Bergh; J. H. Lieske; J. Oberst; J. L. Simon; E. M. Standish; P. Stooke; P. C. Thomas



Determination of 13 elements with atomic numbers between 12 and 47 by 14MeV helium-3 activation analysis  

Microsoft Academic Search

Nuclear reactions for the trace determination of the elements Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Zn, Zr, Nb, Mo, and Ag by activation analysis with 14-MeV ³He ions were investigated. For these reactions, thick target yields were measured and interference-free detection limits were calculated. For an irradiation of 1 h or 1 half-life, whichever is shorter depending on

C. S. Sastri; H. Petri; G. Erdtmann



Temperature dependent flow softening of titanium alloy Ti6Al4V: An investigation using finite element simulation of machining  

Microsoft Academic Search

Titanium alloy Ti6Al4V is the most commonly used titanium alloy in the aerospace and medical device industries due to its superior properties. There has been a considerable amount of research to better understand the serrated chip formation mechanism of titanium alloy Ti6Al4V by using finite element simulation of machining. An accurate representation of the behavior of the material is important

Yi?it Karpat



The Boundary Element Formulation of the 1-Group, 1-D Nodal Equations  

SciTech Connect

A boundary element method is developed for the 1-D nodal diffusion equation in cylindrical geometry. This method retains the matrix qualities of the nodal formulation while providing an accurate computational benchmark for evaluating reactor analysis codes.

B. D. Ganapol; Abderrafi M. Ougouag



Finite Element Simulation of Machining of Ti6Al4V Alloy  

SciTech Connect

Titanium and its alloys are an important class of materials, especially for aerospace applications, due to their excellent combination of strength and fracture toughness as well as low density. However, these materials are generally regarded as difficult to machine because of their low thermal conductivity and high chemical reactivity with cutting tool materials. Moreover, the low thermal conductivity of Titanium inhibits dissipation of heat within the workpiece causing an higher temperature at the cutting edge and generating for higher cutting speed a rapid chipping at the cutting edge which leads to catastrophic failure. In addition, chip morphology significantly influences the thermo-mechanical behaviour at the workpiece/tool interface, which also affects the tool life.In this paper a finite element analysis of machining of TiAl6V4 is presented. In particular, cutting force, chip morphology and segmentation are taken into account due to their predominant roles to determine machinability and tool wear during the machining of these alloys. Results in terms of residual stresses are also presented. Moreover, the numerical results are compared with experimental ones.

Rizzuti, S. [Politecnico di Torino, Dept. of Production Systems and Business Economics, Corso Duca degli Abruzzi 24-10129 Torino (Italy); Umbrello, D. [University of Calabria, Dept. of Mechanical Engineering, Ponte Pietro Bucci 45/C-87036 Rende (Italy)



Recurrent utilization of genetic elements in V regions of antinucleic acid antibodies from autoimmune mice.  


Two IgG anti-DNA and two IgG anti-RNA autoantibodies derived from lupus prone NZB/NZW F1 mice have been analyzed for their Ag fine specificities and for their H and L chain V-region sequences. A remarkable similarity of VH gene sequences with previously sequenced antinucleic acid autoantibodies (Eilat, D., D. M. Webster and A. R. Rees. J. Immunol. 141:1745, 1988) was noted. This finding indicates that a small number of unique VH genes is involved in this autoimmune response and that the sequences of these genes are correlated with the different specificities for the autoantigen. The VK sequences appeared, by computer search, to be selected nonrandomly, but their use was not restricted to autoantibodies. An additional striking feature was evident in the construction of the D region elements, giving rise to CDR3 peptides that can interact with DNA and RNA. These constructs probably include D-D fusion products, which are relatively rare in Ig rearrangements. PMID:1711083

Eilat, D; Fischel, R



Survey of chimeric IStron elements in bacterial genomes: multiple molecular symbioses between group I intron ribozymes and DNA transposons.  


IStrons are chimeric genetic elements composed of a group I intron associated with an insertion sequence (IS). The group I intron is a catalytic RNA providing the IStron with self-splicing ability, which renders IStron insertions harmless to the host genome. The IS element is a DNA transposon conferring mobility, and thus allowing the IStron to spread in genomes. IStrons are therefore a striking example of a molecular symbiosis between unrelated genetic elements endowed with different functions. In this study, we have conducted the first comprehensive survey of IStrons in sequenced genomes that provides insights into the distribution, diversity, origin and evolution of IStrons. We show that IStrons have a restricted phylogenetic distribution limited to two bacterial phyla, the Firmicutes and the Fusobacteria. Nevertheless, diverse IStrons representing two major groups targeting different insertion site motifs were identified. This taken with the finding that while the intron components of all IStrons belong to the same structural class, they are fused to different IS families, indicates that multiple intron-IS symbioses have occurred during evolution. In addition, introns and IS elements related to those that were at the origin of IStrons were also identified. PMID:25324310

Tourasse, Nicolas J; Stabell, Fredrik B; Kolstø, Anne-Brit



Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites  

USGS Publications Warehouse

This paper is the entire report of the IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites, including three annexes. Tables give the recemmended values for the directions of the north poles of rotation and the prime meridians of the planets and satellites. Reference surfaces for mapping these bodies are described. The annexes discuss the guiding principles, given in the body of the report, present explanatory notes, and provide a bibliography of the rotational elements and reference surfaces of the planets and satellites, definitions, and algebraic expressions of relevant parameters. ?? 1980 D. Reidel Publishing Co.

Davies, M. E.; Abalakin, V. K.; Cross, C. A.; Duncombe, R. L.; Masursky, H.; Morando, B.; Owen, T. C.; Seidelmann, P. K.; Sinclair, A. T.; Wilkins, G. A.; Tjuflin, Y. S.



Platinum group elements in a 3.5 Ga nickel-iron occurrence - Possible evidence of a deep mantle origin  

NASA Technical Reports Server (NTRS)

This paper reports the results of new field observations and the geochemical analyses for the area of the Bon Accord (BA) (the Kaapvaal craton, South Africa) Ni-Fe deposit, with particular consideration given to the trace element, platinum-group element, and isotopic (Pb, Nd, and Os) compositions. On the basis of these data, an interpretation of BA is suggested, according to which the BA deposit is a siderophile-rich heterogeneity remaining in the deep mantle after a process of incomplete core formation. The implications of such a model for the study of core-mantle segregation and the geochemistry of the lowermost mantle are discussed.

Tredoux, Marian; Hart, Rodger J.; Lindsay, Nicholas M.; De Wit, Maarten J.; Armstrong, Richard A.



Effects of a Low-Element Challenge Course on Abstinence Self-Efficacy and Group Cohesion  

ERIC Educational Resources Information Center

Substance abuse researchers identify self-efficacy and group cohesion as important components in alcohol and other drug-dependency treatment. Objectives: The purpose of this single-group, pretest-posttest study is to explore the therapeutic value of a challenge course intervention on the self-efficacy and group cohesion of nine chemically…

Clem, Jamie M.; Smith, Thomas E.; Richards, Kristin V.



Threshold effects and renormalization group evolution of neutrino parameters in TeV scale seesaw models  

NASA Astrophysics Data System (ADS)

We consider the threshold effect on the renormalization group (RG) evolution of the neutrino masses and mixing angles in TeV scale seesaw models. We obtain the analytic expressions using the factorization method in the presence of threshold effects. We also perform numerical study of RG effects in two specific low scale seesaw models following the bottom-up approach and ascertain the role of seesaw thresholds in altering the values of masses and mixing angles during RG evolution.

Goswami, Srubabati; Khan, Subrata; Mishra, Sasmita



The eclipsing binary star V380 Gem: First V and Rc light curve analysis and estimation of its absolute elements  

NASA Astrophysics Data System (ADS)

We obtained complete V and Rc light curves of the eclipsing binary V380 Gem in 2012. With our data we were able to determine six new times of minimum light and refine the orbital period of the system to 0.3366088 days. The 2003 version of the Wilson-Devinney code was used to analyze the light curves in the V and Rc bands simultaneously. It is shown that V380 Gem may be classified as an W-type W Ursae Majoris system with a high mass ratio q = 1.45, a degree of contact f = 10.6% the same temperature for both the components (?T = 10 K) and an orbital inclination of i = 81.5°. Our observations show symmetric light curves in all passbands with brightness in both maxima at the same level. The absolute dimensions of V380 Gem are estimated and its dynamical evolution is inferred.

Barani, C.; Martignoni, M.; Acerbi, F.



The enhancing effects of group V ?-hole interactions on the F···O halogen bond.  


The ?-hole interaction, which occurs between the covalent IV-VII atoms and nucleophilic substances, has become a hot issue of weak interaction. In this work, NCF···O=PX3···(NCF)n (X = F, Cl, Br, H, CH3·; n = 0, 1, 2) complexes were constructed and studied based on the second-order Møller-Plesset perturbation theory (MP2) calculations to investigate the enhancing effects of group V ?-hole interactions on the F···O halogen bond. With increasing n, the FO halogen bond becomes stronger, indicating that the group V ?-hole interactions could enhance the F···O halogen bond. As the capacity of donating electrons of X increases, the most negative electrostatic potentials outside the oxygen atom of O=PX3···(NCF)n (n = 0, 1, 2) become more negative, resulting in a stronger F···O halogen bond. In the formation of a F···O halogen bond, along the sequence of X = F, Cl, Br, H, CH3 of the negative sites O=PX3, the electric field of the lone pair of oxygen becomes greater and causes a larger decrease in electron density outside the fluorine atom. On the other hand, with increasing n from 0 to 2, the group V ?-hole interactions also increase the electric field of lone pair of oxygen and results in a larger decrease in electron density outside the fluorine atom. PMID:25099757

Li, Wei; Zeng, Yanli; Zhang, Xueying; Zheng, Shijun; Meng, Lingpeng



Minor/major element variation within and among diogenite and howardite orthopyroxenite groups  

NASA Technical Reports Server (NTRS)

Diogenites are orthopyroxenites that may contain chromite and olivine as accessory minerals. Howardite breccias contain orthopyroxenite clasts with similar properties compared to monomict diogenites. We used statistical methods and variation plots of major and minor elements in orthopyroxene and chromite to show whether or not howardite orthopyroxenites are related to monomict diogenites, and to assess their petrogenesis. Our results fail to establish any evidence that monomict diogenites are significantly different from howardite orthopyroxenites in terms of major and minor elements. We also found no differences between Antarctic diogenites and non-Antarctic diogenites. Although element variation plots show compelling evidence that most diogenites originated by igneous fractionation, linear trends among the various diogenites and howardite orthopyroxenite clasts are either non-existent or ill-defined. This militates against an origin from a single magma body, but suggests an origin from multiple magma bodies in the parent planetoid.

Berkley, John L.; Boynton, Nancy J.



Czochralski growth of heavily indium-doped Si crystals and co-doping effects of group-IV elements  

NASA Astrophysics Data System (ADS)

Heavily indium (In)-doped Si crystals were grown by the Czochralski method under a consideration of the effects of co-doping of electrically neutral group-IV elements (C, Ge or Sn). The In concentration in In-doped Si increased with the amount of In charged into the crucible and reached 3.5×1017 cm-3. The carrier concentration was at most 6×1016 cm-3, limited by the low ionization ratio of ~20% of In. Co-doping of C and Ge effectively enhanced the In concentration while Sn did not, which was examined in terms of the atomistic size, lattice parameter change, mutual bonding energy and solubility of group-IV elements in Si. However, no sufficient increase in carrier concentrations was detected in Si by the co-doping, and formation of some clusters or complexes was suggested.

Inoue, K.; Taishi, T.; Tokumoto, Y.; Kutsukake, K.; Ohno, Y.; Ohsawa, T.; Gotoh, R.; Yonenaga, I.



Review of ductilizing of group via elements by rhenium and other solutes  

Microsoft Academic Search

The properties of Group VIA-base alloys with rhenium (Re) and with other solutes from Groups VIIA and VIIIA were reviewed to determine correlations pertinent to the lowered ductile-brittle transition temperatures observed in both near-saturated and dilute Group VIA-Re alloys. The rhenium ductilizing effect, originally observed in chromium (Cr), molybdenum (Mo), and tungsten (W) alloys containing 25 to 35 atomic percent




Utilizing Prestructured Art Elements in Brief Group Art Therapy with Adolescents  

Microsoft Academic Search

Over the past two decades there has been a steady decrease in the average length of stay in mental health programs, and this phenomenon has necessitated changes in how art therapy services are delivered. This paper presents strategies for utilizing six different prestructured art elements (magazine pictures, magazine words, photocopied images, cut and torn paper, traced shapes, and partial drawings)

Randy M. Vick



The chromosomal distributions of Ty1-copia group retrotransposable elements in higher plants and their implications for genome evolution  

Microsoft Academic Search

Retrotransposons make up a major fraction – sometimes more than 40% – of all plant genomes investigated so far. We have isolated\\u000a the reverse transcriptase domains of the Ty1-copia group elements from several species, ranging in genome size from some 100\\u000a Mbp to 23 000 Mbp, and determined the distribution patterns of these retrotransposons on metaphase chromosomes and within\\u000a interphase

Andrea Brandes; Shin Taketa; Thomas Schmidt; Alexander V. Vershinin; Elena G. Alkhimova; Anette Kamm; Robert L. Doudrick; Trude Schwarzacher; Andreas Katsiotis; Sybille Kubis; Amar Kumar; Steven R. Pearce; Andrew J. Flavell; Gill E. Harrison



Osmium isotopic compositions of Os-rich platinum group element alloys from the Klamath and Siskiyou Mountains  

Microsoft Academic Search

We present new measurements of 186Os\\/188Os and 187Os\\/188Os in 10 Os-rich platinum group element (PGE) alloys from placer deposits formed by the mechanical erosion of peridotite-bearing ophiolites in the Klamath and Siskiyou Mountains in northern California and southwestern Oregon. These data nearly double our database of high-precision 186Os\\/188Os measurements on such samples. Together with previously published data, our new results

Anders Meibom; Robert Frei; Norman H. Sleep



Synthesis and properties of layered synthetic microstructure (LSM) dispersion elements for 62 eV (200A) to 1. 24 keV (10A) radiation. Final report  

SciTech Connect

The opportunities offered by engineered synthetic multilayer dispersion elements for x-rays have been recognized since the earliest days of x-ray diffraction analysis. In this paper, application of sputter deposition technology to the synthesis of Layered Synthetic Microstructure (LSMs) of sufficient quality for use as x-ray dispersion elements is discussed. It will be shown that high efficiency, controllable bandwidth dispersion elements, with d spacings varying from 15 A to 180 A, may be synthesized onto both mechanically stiff and flexible substrates. Multilayer component materials include tungsten, niobium, molybdenum, titanium, vanadium, and silicon layers separated by carbon layers. Experimental observations of peak reflectivity in first order, integrated reflectivity in first order, and diffraction performance at selected photon energies in the range, 100 to 15,000 eV, will be reported and compared to theory.

Barbee, T.W. Jr.



Threat to Valued Elements of Life: The Experience of Dementia across Three Ethnic Groups  

ERIC Educational Resources Information Center

Purpose: There is a fundamental knowledge gap regarding the experience of dementia within minority ethnic groups in the United Kingdom and elsewhere. The present study examined the subjective reality of living with dementia from the perspective of people with dementia within the 3 largest ethnic groups in the United Kingdom. Design and Methods:…

Lawrence, Vanessa; Samsi, Kritika; Banerjee, Sube; Morgan, Craig; Murray, Joanna



Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element  

SciTech Connect

A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40 kW{sub e} space nuclear power system that is similar to the 6 kW{sub e} TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V's do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution.

Wernsman, Bernard [New Mexico Engineering Research Institute Thermionics Evaluation Facility 901 University SE Albuquerque, New Mexico 87106 (United States)



Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element  

SciTech Connect

A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40kW{sub e} space nuclear power system that is similar to the 6kW{sub e} TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V{close_quote}s do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution. {copyright} {ital 1997 American Institute of Physics.}

Wernsman, B. [New Mexico Engineering Research Institute Thermionics Evaluation Facility 901 University SE Albuquerque, New Mexico87106 (United States)



The behaviour of platinum-group elements in basalts from the East Greenland rifted margin  

Microsoft Academic Search

. The continental flood basalts of the East Greenland volcanic rifted margin were extruded during continental breakup above the ancestral Iceland mantle plume at 55 Ma. Three distinct magma types, the low-Ti, high-Ti and very high-Ti series (LTS, HTS and VHTS respectively), are found intercalated in the ~6-km-thick Plateau Lava sequence. Incompatible trace elements indicate that the LTS are derived

Peter Momme; Christian Tegner; Kent C. Brooks; Reid R. Keays



Combined distillation and normal freezing to purify elements of groups II and VI  

NASA Technical Reports Server (NTRS)

A practical system and its application to the purification of Te and Cd is described. Single crystals are grown directly in vitreous silica ampoules subsequently used for sealed Bridgman growth of (Hg-Cd)Te. The system also prepares the ampoules by heating in high vacuum. Purification of the elements is by the combined effect of distillation and normal freezing. Transport and segregation are discussed.

Holland, L. R.



Cis and trans structures of MO 2 groups in dioxo compounds of metals in groups V, VI, VII, and VIII of the periodic table  

Microsoft Academic Search

UDC 548.736 The structures of dioxo compounds of metals in groups V, VI, VII, and VIII have been examined. It is shown that the tendency for the M-O bonds to be linearly or angularly disposed is determined by the formal valence of the metal. Linear MO 2 groups in transition metal compounds should be realized only when an unshared pair

L. O. Atovmyan; M. A. Porai-Koshits



Physicochemical Interaction of Rhenium with Elements of the Platinum Group and Properties of Certain Alloys.  

National Technical Information Service (NTIS)

A review is given of the physicochemical interaction of rhenium with the platinum-group metals (ruthenium, osmium, tungsten, palladium, rhodium, iridium, platinum). The solubility of rhenium in these metals and vice versa is illustrated with graphs. Rheni...

I. A. Tsyganova, M. A. Tylkina, V. P. Polyakova



Abelian groups  

E-print Network

of G . Therefore x is the sum of elements in the G 's, pi p To finish our proof we wish to show this expression is unique. Suppose x ~ yl + y 2 + ~ ~ ~ + yg and m zl + s2 + ~ ~ ~ + s~o Then yl + y 2 + ~ ~ ~ + yy sl + $2 + ~ ~ ~ + zygo so that s... groups. In order to d. o this, we will need the aid. of some vector space theorys D~ef ~tp 4s10 A vector ~sac 7 over the field. P is an abelian group which admits mult1plicatlon by elements of t' he field. such that, for a, b e P and. x, y s V& (l) a...

Bolen, James Cordell



Measurement of the isotopic composition of the iron-group elements in the galactic cosmic radiation  

NASA Technical Reports Server (NTRS)

With an average mass resolution of approximately 0.65 amu the isotopic composition of Cr, Mn, Fe, and Ni in the galactic cosmic radiation has been measured for energies of about 300 to 600 MeV/amu at the detector. Large deviations from solar-system source composition reported by other workers are not observed.

Tarle, G.; Ahlen, S. P.; Cartwright, B. G.



DC dissipation current from elements used for lightning protection on 115 kV transmission lines  

Microsoft Academic Search

The Mississippi Power & Light Company is using different elements in transmission lines and towers to protect the electrical system from direct lightning strokes. According to some theories, the objects to be protected against lightning strokes are better protected by using an element from which the charge dissipation current is enhanced. The authors present the results of an experimental study

S. Grzybowski; A. L. Libby; E. B. Jenkins; C. R. Davis



The group separation of the rare-earth elements and yttrium from geologic materials by cation-exchange chromatography  

USGS Publications Warehouse

Demand is increasing for the determination of the rare-earth elements (REE) and yttrium in geologic materials. Due to their low natural abundance in many materials and the interferences that occur in many methods of determination, a separation procedure utilizing gradient strong-acid cation-exchange chromatography is often used to preconcentrate and isolate these elements from the host-rock matrix. Two separate gradient strong-acid cation-exchange procedures were characterized and the major elements as well as those elements thought to provide the greatest interference for the determination of the REE in geologic materials were tested for separation from the REE. Simultaneous inductively coupled argon plasma-atomic emission spectroscopy (ICAP-AES) measurements were used to construct the chromatograms for the elution studies, allowing the elution patterns of all the elements of interest to be determined in a single fraction of eluent. As a rock matrix, U.S. Geological Survey standard reference BCR-1 basalt was digested using both an acid decomposition procedure and a lithium metaborate fusion. Hydrochloric and nitric acids were tested as eluents and chromatograms were plotted using the ICAP-AES data; and we observed substantial differences in the elution patterns of the REE and as well as in the solution patterns of Ba, Ca, Fe and Sr. The nitric acid elution required substantially less eluent to elute the REE and Y as a group when compared to the hydrochloric acid elution, and provided a clearer separation of the REE from interfering and matrix elements. ?? 1984.

Crock, J.G.; Lichte, F.E.; Wildeman, T.R.



Uniform convergence of multigrid V-cycle on adaptively refined finite element meshes for second order elliptic problems  

Microsoft Academic Search

In this paper we prove the uniform convergence of the standard multigrid V-cycle algorithm with the Gauss-Seidel relaxation\\u000a performed only on the new nodes and their “immediate” neighbors for discrete elliptic problems on the adaptively refined finite\\u000a element meshes using the newest vertex bisection algorithm. The proof depends on sharp estimates on the relationship of local\\u000a mesh sizes and a

Haijun Wu; Zhiming Chen



Labile trace elements in basaltic achondrites: Can they distinguish between meteorites from the Moon, Mars, and V-type asteroids?  

NASA Astrophysics Data System (ADS)

We report data for 14 mainly labile trace elements (Ag, Au, Bi, Cd, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn) in eight whole-rock lunar meteorites (Asuka [A-] 881757, Dar al Gani [DaG] 262, Elephant Moraine [EET] 87521, Queen Alexandra Range [QUE] 93069, QUE 94269, QUE 94281, Yamato [Y-] 793169, and Y-981031), and Martian meteorite (DaG 476) and incorporate these into a comparative study of basaltic meteorites from the Moon, Mars, and V-type asteroids. Multivariate cluster analysis of data for these elements in 14 lunar, 13 Martian, and 34 howardite, eucrite, and diogenite (HED) meteorites demonstrate that materials from these three parents are distinguishable using these markers of late, low-temperature episodes. This distinguishability is essentially as complete as that based on markers of high-temperature igneous processes. Concentrations of these elements in 14 lunar meteorites are essentially lognormally distributed and generally more homogeneous than in Martian and HED meteorites. Mean siderophile and labile element concentrations in the 14 lunar meteorites indicate the presence of a CI-equivalent micrometeorite admixture of 2.6% When only feldspathic samples are considered, our data show a slightly higher value of 3.4% consistent with an increasing micrometeorite content in regolith samples of higher maturity. Concentrations of labile elements in the 8 feldspathic samples hint at the presence of a fractionated highly labile element component, possibly volcanic in origin, at a level comparable to the micrometeorite component. Apparently, the process(es) that contributed to establishing lunar meteorite siderophile and labile trace element contents occurred in a system open to highly labile element transport.

Wolf, Stephen F.; Wang, Ming-Sheng; Lipschutz, Michael E.



arXiv:1010.6007v1[math.OC]28Oct2010 A Separation Principle on Lie Groups  

E-print Network

arXiv:1010.6007v1[math.OC]28Oct2010 A Separation Principle on Lie Groups S. Bonnabel P. Martin P is time-invariant. This paper addresses the issue of a non- linear separation principle on Lie groups. For invariant systems on Lie groups, we prove there exists a large set of (time-varying) trajectories around

Boyer, Edmond


Consensus recommendations for common data elements for operational stress research and surveillance: report of a federal interagency working group.  


Empirical studies and surveillance projects increasingly assess and address potentially adverse psychological health outcomes from the stress of military operations, but no standards yet exist for common concept definitions, variable categories, and measures. This article reports the consensus recommendations of the federal interagency Operational Stress Working Group for common data elements to be used in future operational stress research and surveillance with the goal of improving comparability across studies. Operational stress encompasses more than just combat; it occurs everywhere service members and their families live and work. Posttraumatic stress is not the only adverse mental or behavioral health outcome of importance. The Operational Stress Working Group contends that a primary goal of operational stress research and surveillance is to promote prevention of adverse mental and behavioral outcomes, especially by recognizing the preclinical and subclinical states of distress and dysfunction that portend a risk for failure of role performance or future mental disorders. Recommendations for data elements are divided into 3 tiers: core, supplemental, and emerging, including variable domains and specific measures for assessing operational stressor exposures, stress outcomes, moderating factors, and mediating processes. Attention is drawn to the emerging construct of stress injury as a generic term for subclinical operational stress, and to emerging data elements addressing biological, psychological, and spiritual mediators of risk. Methodologies are needed for identifying preclinical and subclinical states of distress or dysfunction that are markers of risk for failure of role performance and future clinical mental disorders, so that targeted prevention interventions can be developed and evaluated. PMID:21044711

Nash, William P; Vasterling, Jennifer; Ewing-Cobbs, Linda; Horn, Sarah; Gaskin, Thomas; Golden, John; Riley, William T; Bowles, Stephen V; Favret, James; Lester, Patricia; Koffman, Robert; Farnsworth, Laura C; Baker, Dewleen G



Chromosomal Homology and Molecular Organization of Muller's Elements D and E in the Drosophila Repleta Species Group  

PubMed Central

Thirty-three DNA clones containing protein-coding genes have been used for in situ hybridization to the polytene chromosomes of two Drosophila repleta group species, D. repleta and D. buzzatii. Twenty-six clones gave positive results allowing the precise localization of 26 genes and the tentative identification of another nine. The results were fully consistent with the currently accepted chromosomal homologies and in no case was evidence for reciprocal translocations or pericentric inversions found. Most of the genes mapped to chromosomes 2 and 4 that are homologous, respectively, to chromosome arms 3R and 3L of D. melanogaster (Muller's elements E and D). The comparison of the molecular organization of these two elements between D. melanogaster and D. repleta (two species that belong to different subgenera and diverged some 62 million years ago) showed an extensive reorganization via paracentric inversions. Using a maximum likelihood procedure, we estimated that 130 paracentric inversions have become fixed in element E after the divergence of the two lineages. Therefore, the evolution rate for element E is approximately one inversion per million years. This value is comparable to previous estimates of the rate of evolution of chromosome X and yields an estimate of 4.5 inversions per million years for the whole Drosophila genome. PMID:9071584

Ranz, J. M.; Segarra, C.; Ruiz, A.



Common data elements for pediatric traumatic brain injury: recommendations from the working group on demographics and clinical assessment.  


The Common Data Elements (CDEs) initiative is a National Institutes of Health (NIH) interagency effort to standardize naming, definitions, and data structure for clinical research variables. Comparisons of the results of clinical studies of neurological disorders have been hampered by variability in data coding, definitions, and procedures for sample collection. The CDE project objective is to enable comparison of future clinical trials results in major neurological disorders, including traumatic brain injury (TBI), stroke, multiple sclerosis, and epilepsy. As part of this effort, recommendations for CDEs for research on TBI were developed through a 2009 multi-agency initiative. Following the initial recommendations of the Working Group on Demographics and Clinical Assessment, a separate workgroup developed recommendations on the coding of clinical and demographic variables specific to pediatric TBI studies for subjects younger than 18 years. This article summarizes the selection of measures by the Pediatric TBI Demographics and Clinical Assessment Working Group. The variables are grouped into modules which are grouped into categories. For consistency with other CDE working groups, each variable was classified by priority (core, supplemental, and emerging). Templates were produced to summarize coding formats, guide selection of data points, and provide procedural recommendations. This proposed standardization, together with the products of the other pediatric TBI working groups in imaging, biomarkers, and outcome assessment, will facilitate multi-center studies, comparison of results across studies, and high-quality meta-analyses of individual patient data. PMID:21939389

Adelson, P David; Pineda, Jose; Bell, Michael J; Abend, Nicholas S; Berger, Rachel P; Giza, Christopher C; Hotz, Gillian; Wainwright, Mark S



Teoria dei gruppi. — Some remarks on groups in which elements with the same p  

Microsoft Academic Search

I nthis paper we characterize certain classes of groupsG in which, fromxp = yp (x;y ? G;p a fixed prime), it follows that xy = yx. Our results extend results previously obtained by other authors, in the finite case.

Socio G. Zappa


Which Social Elements Are Visible in Virtual Groups? Addressing the Categorization of Social Expressions  

ERIC Educational Resources Information Center

Learning is a social process. That is why it is extremely important to understand how students interact socially in online courses and how it affects the learning process. However, social aspects, understood as those expressions or comments that go beyond strictly academic interaction, i.e. the need to carry out group work, are not clearly…

Perez-Mateo, M.; Guitert, M.



Contribution of Exogenous Genetic Elements to the Group A Streptococcus Metagenome  

Microsoft Academic Search

Variation in gene content among strains of a bacterial species contributes to biomedically relevant differences in phenotypes such as virulence and antimicrobial resistance. Group A Streptococcus (GAS) causes a diverse array of human infections and sequelae, and exhibits a complex pathogenic behavior. To enhance our understanding of genotype-phenotype relationships in this important pathogen, we determined the complete genome sequences of

Stephen B. Beres; James M. Musser; Niyaz Ahmed



Crystal Field Theory and the Angular Overlap Model Applied to Hydrides of Main Group Elements.  

ERIC Educational Resources Information Center

Described is how crystal field theory and the angular overlap model can be applied to very simple molecules which can then be used to introduce such concepts as bonding orbitals, MO diagrams, and Walsh diagrams. The main-group compounds are used as examples and a switch to the transition metal complexes. (KR)

Moore, E. A.



Structure and optical properties of evaporated films of the Cr- and V-group metals  

NASA Technical Reports Server (NTRS)

Thin films of Cr, Mo, and W rapidly evaporated in high vacuum (5 x 10 to the -7th torr) onto room-temperature substrates show anomalously low reflectance (compared to bulk samples). From electron and X-ray diffraction and electron microscopy, the normal bcc crystal structure is found, but with very fine grains. Columnar grains about 100 A in diameter were separated by a less dense grain-boundary network about 10-A wide. The measured optical conductivity agrees with an inhomogeneous-medium model that assumes the normal crystalline conductivity for the grain interiors, with model parameters that correlate to the observed columnar grain size. In contrast, V and Nb films rapidly evaporated onto room-temperature substrates have the reflectance of bulk crystalline material. On liquid-nitrogen temperature substrates, however, V and Nb have normal bcc crystal structure but with small flat-plate grains, and the same model, with appropriate parameters, accounts for the optical conductivity. The difference between these two groups apparently depends on residual gases segregated at the grain boundaries in the Cr-group films.

Nestell, J. E., Jr.; Christy, R. W.; Cohen, M. H.; Ruben, G. C.



Exploring cryogenic focused ion beam milling as a Group III-V device fabrication tool  

NASA Astrophysics Data System (ADS)

In this paper, we compare the features observed on a Group III-V strained layer superlattice (SLS) materials system as a result of room temperature Ga+ focused ion beam (FIB) milling to the features observed as a result of cryogenic FIB (cryo-FIB) milling at -135 °C under the same beam conditions (30 kV:1 nA). The features on the cryo-FIB milled material were observed both when the material was still cold and after it returned to room temperature. Although cryo-FIB milling yielded patterned features that were initially cleaner than comparable features defined by FIB milling at room temperature, we found that both room temperature FIB milling and cryo-FIB milling with subsequent sample warm-up resulted in the formation of Group III enriched features. These findings suggest that the structural and chemical properties of features fabricated by cryo-FIB milling are temperature-dependent, which is an important consideration when it comes to device fabrication. These dependencies will need to be better understood and controlled if cryo-FIB milling is to have future applications in this area.

Dolph, Melissa Commisso; Santeufemio, Christopher



Cipollone v. Liggett Group, Inc. strengthens federal preemption defense in pesticide tort litigation  

SciTech Connect

When the United States Supreme Court held that the Federal Cigarette Labeling and Advertising Act (Cigarette Act) of 1969 preempted plaintiff`s failure to warn claims in Cipollone v. Liggett Group, Inc., the decision directly affected a far wider range of product liability cases than those involving only cigarettes. This article analyzes how Cipollone affects the defense raised in pesticide injury cases that the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) preempts state common law failure to warn claims. The Eleventh Circuit in Papas v. Upjohn Co. (Papas I), declining to follow contrary authority, held that FIFRA impliedly preempted state law claims that pesticides were inadequately labeled. On a petition for certiorari, the Supreme Court remanded the case back to the Eleventh Circuit for reconsideration in light of Cipollone. Recently, the Eleventh Circuit in Papas v. Upjohn Co. (Papas II) applied Cipollone to hold that FIFRA expressly preempts the state law claims. This article argues that Papas II correctly held, after Cipollone, that FIFRA preempts the state inadequate labeling and failure to warn claims in pesticide cases. 86 refs.

Stevens, R.W. [George Washington Univ. National Law Center, Washington, DC (United States)



More than 1000 ultraconserved elements provide evidence that turtles are the sister group of archosaurs  

PubMed Central

We present the first genomic-scale analysis addressing the phylogenetic position of turtles, using over 1000 loci from representatives of all major reptile lineages including tuatara. Previously, studies of morphological traits positioned turtles either at the base of the reptile tree or with lizards, snakes and tuatara (lepidosaurs), whereas molecular analyses typically allied turtles with crocodiles and birds (archosaurs). A recent analysis of shared microRNA families found that turtles are more closely related to lepidosaurs. To test this hypothesis with data from many single-copy nuclear loci dispersed throughout the genome, we used sequence capture, high-throughput sequencing and published genomes to obtain sequences from 1145 ultraconserved elements (UCEs) and their variable flanking DNA. The resulting phylogeny provides overwhelming support for the hypothesis that turtles evolved from a common ancestor of birds and crocodilians, rejecting the hypothesized relationship between turtles and lepidosaurs. PMID:22593086

Crawford, Nicholas G.; Faircloth, Brant C.; McCormack, John E.; Brumfield, Robb T.; Winker, Kevin; Glenn, Travis C.



Division IX / Commission 30 / Working Group Catalog of Orbital Elements of Spectroscopic Binaries  

NASA Astrophysics Data System (ADS)

The SB9 Working Group of Commission 30 aims at compiling the 9th Catalogue of Orbits of Spectroscopic Binaries. By definition, this is a never ending task as orbits of newly discovered systems keep appearing in the literature. Despite this, the working group tries to catch up with the delay as nothing was done in between 1989 when the 8th catalogue by Batten et al. and 2000 when the WG was settled. In 2006, at its business meeting, the WG decided to focus on the completeness of systems rather than on completeness of orbits. If the latter is a valuable objective, only the former is useful to any statistical investigation of spectroscopic binaries.

Pourbaix, Dimitri; Young, Andrew T.; Batten, Alan H.; Fekel, Francis C.; Hartkopf, William I.; Levato, Hugo; Morrell, Nidia I.; Tokovinin, Andrei A.; Torres, Guillermo; Udry, Stepane


Osmium-Isotope and Platinum-Group-Element Systematics of Impact-Melt Rocks, Chesapeake Bay Impact Structure, Virginia, USA  

NASA Technical Reports Server (NTRS)

Osmium (Os) isotopes and platinum-group elements (PGEs) are useful for geochemically identifying a meteoritic component within impact structures, because meteorites are typically characterized by low (187)Os/(188)Os ratios and high PGE concentrations. In contrast, most types of crustal target rocks have high radiogenic Os and very low PGE concentrations. We have examined Os isotope and PGE systematics of impact-melt rocks and pre-impact target rocks from a 2004 test hole in the late Eocene Chesapeake Bay impact structure and from nearby coreholes. Our goal is to determine the proportion of the projectile component in the melt rock Additional information is included in the original extended abstract.

Lee, Seung Ryeol; Wright Horton, J., Jr.; Walker, Richard J.



Mobilization of the platinum group elements by low-temperature fluids: Implications for mineralization and the iridium controversy  

NASA Technical Reports Server (NTRS)

Geochemical investigations on the widely dispersed Late Proterozoic Acraman impact ejecta horizon and its host marine shales in the Adelaide Geosyncline provide strong evidence for low-temperature mobilization of the platinum group elements (PGE), including Ir. The ejecta horizon was formed when the middle Proterozoic dacitic volcanics in the Gawler Ranges, central South Australia, were impacted by a very large (ca. 4 km) meteorite. The resulting structure, now represented by Lake Acraman, is Australia's largest meteorite impact structure. Debris from the impact was blasted for many hundreds of kilometers, some falling into the shallow sea of the Adelaide Geosyncline, some 300 km to the east of the impact site.

Dowling, Kim; Keays, Reid R.; Wallace, Malcolm W.; Gostin, Victor A.



Average bond energies between boron and elements of the fourth, fifth, sixth, and seventh groups of the periodic table  

NASA Technical Reports Server (NTRS)

The average bond energies D(gm)(B-Z) for boron-containing molecules have been calculated by the Pauling geometric-mean equation. These calculated bond energies are compared with the average bond energies D(exp)(B-Z) obtained from experimental data. The higher values of D(exp)(B-Z) in comparison with D(gm)(B-Z) when Z is an element in the fifth, sixth, or seventh periodic group may be attributed to resonance stabilization or double-bond character.

Altshuller, Aubrey P



"Reference values" of trace elements in the hair of a sample group of Spanish children (aged 6-9 years) - are urban topsoils a source of contamination?  


Human hair is used as a biomonitor to evaluate the environmental exposure to contaminants in the individual. However, the use of human hair is controversial, mainly because reference levels for pollutants in hair have not yet been set. In the case of Spain, few biomonitoring studies have involved infants and children. A biomonitoring study was conducted to investigate the possible normal values of trace elements of toxicological concern in children aged 6-9 years from the city of Alcalá de Henares, Community of Madrid (Spain), following the methodology and strict inclusion criteria previously developed by our group. Levels of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Ti, Tl, V and Zn were monitored in scalp-hair from 117 healthy children (47 boys and 70 girls) between April and May of 2001. The levels of trace elements here described could be considered as possible "reference values" for children aged 6-9 years resident in the Community of Madrid. These values might also be selected as a preliminary screening tool to evaluate if a Spanish child has been exposed to any of the contaminants studied here. This study also investigated whether local urban topsoils were a source of metals for this population. PMID:24930126

Peña-Fernández, A; González-Muñoz, M J; Lobo-Bedmar, M C



Efficiency of group implicit concurrent algorithms for transient finite element analysis  

NASA Technical Reports Server (NTRS)

The performance of group implicit algorithms is assessed on actual concurrent computers. It is shown that, as the number of subdomains is increased, performance enhancements are derived from two sources: the increased parallelism in the computations; and a reduction in equation solving effort. Moreover, these two performance enhancements are synergistic, in the sense that the corresponding speed-ups are multiplied, rather than merely added. Simulations on a 32-node hypercube are presented for which the interprocessor communications efficiencies obtained are consistently in excess of 90 percent.

Ortiz, M.; Sotelino, E. D.; Nour-Omid, B.



Distribution of platinum-group elements in the Bati Kef chromite deposit, Guleman-Elazig area, eastern Turkey.  

USGS Publications Warehouse

The distribution of platinum-group elements (PGE) within chromite deposits from an ophiolite is determined and their geochemistry compared with chromitites from ophiolites and from stratiform layered complexes elsewhere in the world. The Guleman area chromitites are lenses of layered massive to disseminated chromite in dunite or sheared harzburgite along and near the dunite-harzburgite contact. PGE were analysed by a fire assay/spectrographic method. The analyses, in ppb, varied narrowly near the detection limits; only Ir was mostly detected (24-27 ppb) . The data plot as independent, slight variations of individual PGE with crude and irregular spatial distributions, oriented with respect to the land surface. Based on studies elsewhere, the PGE reside mostly in laurite, erlichmanite and Os/Ir alloys included within or interstitial to chromite. Average values for each PGE were normalized with respect to average chondrite concentrations for these elements. All patterns for ophiolite-chromitites (5) show depletion of these elements relative to chondrite average concentrations, with greater depletion in Pt and Pd than in Ir and Ru, to produce patterns with negative slopes. Chromitites from differentiated stratiform complexes (2) yield patterns with positive slopes. -G.J.N.

Page, N. J.; Engin, T.; Singer, D. A.; Haffty, J.



Creep deformation and fracture of a Cr/Mo/V bolting steel containing selected trace-element additions  

NASA Astrophysics Data System (ADS)

The article reports the creep behavior, at 565 °C, of 1Cr1Mo0.75V (Ti, B) (Durehete D1055) steel, in each of two grain sizes and doped with individual trace elements such as P, As, and Sn, in comparison to a reference cast of the base material containing 0.08 wt pct Ti. The addition of the trace elements P, As, or Sn (each <0.045 wt pct) appears to produce no significant effect on creep strength or creep crack-growth resistance at 565 °C. The fine-grained material shows low creep strength but notch strengthening, while the coarse-grained material shows higher creep strength and exhibits notch weakening for test times up to 2750 hours. From creep crack-growth tests, it appears that the C* parameter is not appropriate for correlating the creep crack-growth rate under the present test conditions. The parameters K I or ? net are found to correlate better, but, from the present data, it is not possible to judge which of these parameters is more appropriate for general use. It is suggested that the presence of Ti in CrMoV steels has an inhibiting effect on trace-element embrittlement.

Larouk, Z.; Pilkington, R.



Creep deformation and fracture of a Cr/Mo/V bolting steel containing selected trace-element additions  

SciTech Connect

The article reports the creep behavior, at 565 C, of 1Cr1Mo0.75V (Ti, B) (Durehete D1055) steel, in each of two grain sizes and doped with individual trace elements such as P, As, and Sn, in comparison to a reference cast of the base material containing 0.08 wt pct Ti. The addition of the trace elements P, As, or Sn (each <0.045 wt pct) appears to produce no significant effect on creep strength or creep crack-growth resistance at 565 C. The fine-grained material shows low creep strength but notch strengthening, while the coarse-grained material shows higher creep strength and exhibits notch weakening for test times up to 2750 hours. From creep crack-growth tests, it appears that the C{sup *} parameter is not appropriate for correlating the creep crack-growth rate under the present test conditions. The parameters K{sub I} or {sigma}{sub net} are found to correlate better, but, from the present data, it is not possible to judge which of these parameters is more appropriate for general use. It is suggested that the presence of Ti in CrMoV steels has an inhibiting effect on trace-element embrittlement.

Larouk, Z. [Univ. of Constantine (Algeria). Inst. of Physics; Pilkington, R. [Univ. of Manchester (United Kingdom). Materials Science Centre



Effects of liquid immiscibility on trace element fractionation in magmatic iron meteorites: A case study of group IIIAB  

NASA Astrophysics Data System (ADS)

Magmatic iron meteorites are generally agreed to represent metal that crystallized in asteroidal cores from a large pool of liquid. Estimates suggest that the metallic liquid contained significant amounts of S and P, both of which are incompatible and exert a strong effect on trace-element partitioning. In tandem, S and P are also prone to cause immiscibility between sulfide liquid and P-rich metal liquid. The liquid immiscibility field occupies about 70% of the portion of the Fe-Ni-S-P system in which iron is the first phase to crystallize. In spite of this, previous fractional crystallization models have taken into account only one liquid phase and have encountered significant discrepancies between the meteorite data and model values for the key elements Ni, Ir, Ga, Ge and Au at even moderate degrees of fractionation. For the first time, a model for trace-element partitioning between immiscible liquids in the Fe-Ni-S-P system is presented in order to assess the effects on fractionation in magmatic iron meteorite groups. The onset of liquid immiscibility causes a significant change in the enrichment patterns of S and P in both liquids, so elements with contrasting partitioning behavior will show trends deviating clearly from one-liquid trends. A trend recorded in the solid metal will either be a smooth curve as long as equilibrium is maintained between the two liquids or the trend may diverge into a field limited by two extreme curves depending on the degree of disequilibrium. Bulk initial liquids for most magmatic groups have S/P (wt%) ratios well below 25. In these cases, and due to the constitution of the Fe-Ni-S-P system, most of the metal will crystallize from the rapidly decreasing volume of metal liquid and only a subordinate amount from the sulfide liquid. Because of the strong extraction of P into the metal liquid, P will have a much larger influence on trace-element partitioning than a low initial P content might suggest. My model calculations suggest that liquid immiscibility played a significant role during the solidification of the IIIAB parent body's core. The two-liquid model reproduces the IIIAB trends more closely than previous one-liquid models and can account for: a) the general widening of the IIIAB trend with increasing Ni and decreasing Ir contents, b) the occurrence of high-Ni members which are not strongly depleted in Ir, Ga and Ge and c) an upper limit at about 11 wt% Ni where the metal liquid was almost consumed.

Ulff-Moeller, Finn



Conversion of paraffins to aromatics over zeolites modified with oxides of group IIIA, IVA and VA elements  

SciTech Connect

A process is described for producing aromatic hydrocarbons, the process comprising contacting one or more C/sub 2/-C/sub 12/ alkanes with a catalyst comprising a crystalline zeolite material having the structure of ZSM-5 or ZSM-11, the contacting taking place under aromatization conditions including a temperature of from about 200/sup 0/C to about 700/sup 0/C, a pressure of from about 0.1 atmosphere to about 60 atmospheres, a weight hourly spaced velocity (WHSV) of from about 0.1 to about 400 and a hydrogen/hydrocarbon mole ratio of from about 0 to about 20, the catalyst further comprising an oxide of a Group IIIA, IVA or VA element, the oxide being incorporated into the catalyst by a modification process comprising the steps of: (i) contacting the ZSM-5 or ZSM-11 with a solution or neat liquid of a compound of the Group IIIA, IVA or VA element, thereby impregnating the ZSM-5 or ZSM-11 with the compound; and (ii) heating the impregnated ZSM-5 or ZSM-11 or step (i) for at least one hour at a temperature of at least 150/sup 0/C.

Chu, C.-C.



Anti-Bactericidal Properties of Stingray Dasyatis pastinaca Groups V, IIA, and IB Phospholipases A2: A Comparative Study.  


Group IIA secreted phospholipase A2 (group IIA sPLA2) is known to display potent Gram-positive bactericidal activity in vitro and in vivo. We have analyzed the bactericidal activity of the full set of native stingray and dromedary groups V, IIA, and IB sPLA2s on several Gram-positive and Gram-negative strains. The rank order potency among both marine and mammal sPLA2s against Gram-positive bacteria is group IIA?>?V?>?IB, whereas Gram-negative bacteria exhibited a much higher resistance. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2.The bactericidal efficiency of groups V and IIA sPLA2s was shown to be dependent upon the presence of calcium ions and to a less extent Mg(2+) ions and then a correlation could be made to its hydrolytic activity of membrane phospholipids. Importantly, we showed that stingray and dromedary groups V, IIA, and IB sPLA2s present no cytotoxicity after their incubation with MDA-MB-231cells. stingray groups V and IIA sPLA2s, like mammal ones, may be considered as future therapeutic agents against bacterial infections. PMID:25119545

Bacha, Abir Ben



Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation  

USGS Publications Warehouse

The major element relationships in ferromanganese (Fe-Mn) crusts from Afanasiy-Nikitin seamount (ANS), eastern equatorial Indian Ocean, appear to be atypical. High positive correlations (r = 0.99) between Mn/Co and Fe/Co ratios, and lack of correlation of those ratios with Co, Ce, and Ce/Co, indicate that the ANS Fe-Mn crusts are distinct from Pacific seamount Fe-Mn crusts, and reflect region-specific chemical characteristics. The platinum group elements (PGE: Ir, Ru, Rh, Pt, and Pd) and Au in ANS Fe-Mn crusts are derived from seawater and are mainly of terrestrial origin, with a minor cosmogenic component. The Ru/Rh (0.5-2) and Pt/Ru ratios (7-28) are closely comparable to ratios in continental basalts, whereas Pd/Ir ratios exhibit values ( 0.75) correlations between water depth and Mn/Co, Fe/Co, Ce/Co, Co, and the PGEs. Fractionation of the PGE-Au from seawater during colloidal precipitation of the major-oxide phases is indicated by well-defined linear positive correlations (r > 0.8) of Co and Ce with Ir, Ru, Rh, and Pt; Au/Co with Mn/Co; and by weak or no correlations of Pd with water depth, Co-normalized major-element ratios, and with the other PGE (r < 0.5). The strong enrichment of Pt (up to 1 ppm) relative to the other PGE and its positive correlations with Ce and Co demonstrate a common link for the high concentrations of all three elements, which likely involves an oxidation reaction on the Mn-oxide and Fe-oxyhydroxide surfaces. The documented fractionation of PGE-Au and their positive association with redox sensitive Co and Ce may have applications in reconstructing past-ocean redox conditions and water masses.

Banakar, V.K.; Hein, J.R.; Rajani, R.P.; Chodankar, A.R.



Host isotope mass effects on the hyperfine interaction of group-V donors in silicon  

NASA Astrophysics Data System (ADS)

The effects of host isotope mass on the hyperfine interaction of group-V donors in silicon are revealed by pulsed electron nuclear double resonance (ENDOR) spectroscopy of isotopically engineered Si single crystals. Each of the hyperfine-split 31P, As75, Sb121, Sb123, and Bi209 ENDOR lines splits further into multiple components, whose relative intensities accurately match the statistical likelihood of the nine possible average Si masses in the four nearest-neighbor sites due to random occupation by the three stable isotopes Si28, Si29, and Si30. Further investigation with 31P donors shows that the resolved ENDOR components shift linearly with the bulk-averaged Si mass.

Sekiguchi, T.; Tyryshkin, A. M.; Tojo, S.; Abe, E.; Mori, R.; Riemann, H.; Abrosimov, N. V.; Becker, P.; Pohl, H.-J.; Ager, J. W.; Haller, E. E.; Thewalt, M. L. W.; Morton, J. J. L.; Lyon, S. A.; Itoh, K. M.



Exciton annihilation and dissociation dynamics in group II-V Cd3P2 quantum dots.  


Semiconductor quantum dots (QDs) have emerged as a new class of light harvesting materials for solar energy conversion due to their unique size-dependent properties. Most recent studies have focused on II-VI group (such as CdX, X = S, Se, and Te) QDs and lead salt (such as PbS, PbSe, and PbTe) QDs. In this paper, we investigate exciton dissociation and annihilation dynamics of Cd3P2 QDs, a low bulk band gap (0.55 eV) II-V group material, to explore their potential application as a light harvesting component for photoreduction systems. For Cd3P2 QDs with 1S exciton band at 650 nm, a long-lived single exciton state with lifetime of 259 ns and a high emission quantum yield of 65% were observed. In Cd3P2 QD-rhodamine B (RhB, an electron acceptor) complexes, excitons in QDs could be dissociated by ultrafast electron transfer to RhB (6.2 ps), and the charge separated state had a long lifetime (31 ns). Although the photoinduced electron transfer rate in QD-RhB complexes decreased with increasing QD size, electron transfer was observed in QDs with 1S exciton bands at wavelength as long as 1050 nm. Compared with CdSe and PbS, Cd3P2 QDs with both more strongly reducing excited states and broader absorption in the visible and near IR region can be readily achieved, making them potential photosensitizers for photodriven water or CO2 reduction reactions. PMID:23611312

Wu, Kaifeng; Liu, Zheng; Zhu, Haiming; Lian, Tianquan



Low keV electron probe analysis of silicate minerals for Mg, Al, and Si using pure-element standards  

NASA Technical Reports Server (NTRS)

Accurate electron probe values for Mg, Al, and Si in silicate minerals may be obtained with pure-element standards. Analysis must be done at low (6 kV) accelerating potential and for best results, the average atomic number of the sample should be within about plus or minus 1 of the atomic number of the pure-element standard. This last requirement is automatically fulfilled for most common silicate minerals, as their average atomic numbers usually fall within the 11 to 15 range. Examples studied include a wet-chemically analyzed cordierite containing 17.71 weight percent Al, for which a value of 17.6 plus or minus 0.3 percent was obtained with the electron probe, and a hornblende containing 19.15 percent Si, which gave 19.0 plus or minus 0.3 percent using the probe method.

Cunningham, G. G.



Fast-neutron gamma-ray production from elemental iron: E\\/sub n\\/ < or approx. = 2 MeV. [Differential cross sections, excitation functions  

Microsoft Academic Search

A Ge(Li) detector and a fission detector were used to measure elemental differential cross section excitation functions for fast-neutron gamma-ray production from iron relative to fast-neutron fission of ²³U. Data were acquired at approximately 50 keV intervals with approximately 50 keV neutron-energy resolution from near threshold to approximately 2 MeV. Angular distributions for the 0.847-MeV gamma ray were measured at



Group method solutions of the generalized forms of Burgers, Burgers–KdV and KdV equations with time-dependent variable coefficients  

Microsoft Academic Search

Solutions for the generalized forms of Burgers, Burgers–KdV, and KdV equations with time-dependent variable coefficients and\\u000a with initial and boundary conditions are constructed. The analysis rests mainly on the standard group method. Similarity solutions\\u000a are found which reduce the nonlinear system of partial differential equations to systems of ordinary differential equations\\u000a to obtain some exact solutions and others as numerical

Mina B. Abd-el-Malek; Medhat M. Helal


Modeling Group IV elements with new transferable tight-binding models  

SciTech Connect

An outstanding problem in the computer-based microscopic description of Group IV materials, is the need for an accurate transferable model of the energetic and electronic properties of semiconductor structures. The three complementary approaches have been the ab-initio method including Car-Parinello simulations, the classical molecular dynamics method, and tight-binding molecular dynamics. While being very accurate, the ab-initio molecular dynamics has been performed on small systems ({approximately}100 atoms) for short time scales ({approximately}10 ps). On the other hand, classical potential models have had much success in describing melting of silicon, amorphous silicon structures, thin film growth and a variety of computationally intensive molecular dynamics simulations. However, the classical based models do not contain important electronic information which is essential in a variety of problems in electronic materials such as determining the gap states for structural defects. The accuracy of the classical models in configurations, far from the fitting database, may be uncertain. Our approach is to find transferable tight-binding models for silicon that are in between the ab-initio simulations and the classical models for molecular dynamics in level of sophistication.

Kwon, I. [Los Alamos National Lab., NM (United States); Biswas, R. [Iowa State Univ. of Science and Technology, Ames, IA (United States)



Does common spatial origin promote the auditory grouping of temporally separated signal elements in grey treefrogs?  

PubMed Central

‘Sequential integration’ represents a form of auditory grouping in which temporally separated sounds produced by the same source are perceptually bound together over time into a coherent ‘auditory stream’. In humans, sequential integration plays important roles in music and speech perception. In this study of the grey treefrog (Hyla chrysoscelis), we took advantage of female selectivity for advertisement calls with conspecific pulse rates to investigate common spatial location as a cue for sequential integration. We presented females with two temporally interleaved pulse sequences with pulse rates of 25 pulses/s, which is half the conspecific pulse rate and more similar to that of H. versicolor, a syntopically breeding heterospecific. We tested the hypothesis that common spatial origin between the two pulse sequences would promote their integration into a coherent auditory stream with an attractive conspecific pulse rate. As the spatial separation between the speakers broadcasting the interleaved pulse sequences decreased from 180° to 0°, more females responded and females exhibited shorter response latencies and travelled shorter distances en route to a speaker. However, even in the 180° condition, most females (74%) still responded. Detailed video analyses revealed no evidence to suggest that patterns of female phonotaxis resulted from impaired abilities to localize sound sources in the spatially separated conditions. Together, our results suggest that females were fairly permissive of spatial incoherence between the interleaved pulses sequences and that common spatial origin may be only a relatively weak cue for sequential integration in grey treefrogs. PMID:19727419

Bee, Mark A.; Riemersma, Kasen K.



I. ASCRC General Education Form Group V Literary and Artistic Studies  

E-print Network

/Russian; cross-listed with Liberal Studies Course # MCLG 307V/ RUSS 307V; LS 307V Course Title Introduction to 20, postmodernism/post-Soviet) using a wide range of critical approaches, from formalism and structuralism

Vonessen, Nikolaus


An Instrument to Measure Elemental Energy Spectra of Cosmic Ray Nuclei Up to 10(exp 16) eV  

NASA Technical Reports Server (NTRS)

A longstanding goal of cosmic ray research is to measure the elemental energy spectra of cosmic rays up to and through the "knee" (approx. equal to 3 x 10 (exp 15) eV. It is not currently feasible to achieve this goal with an ionization calorimeter because the mass required to be deployed in Earth orbit is very large (at least 50 tonnes). An alternative method will be presented. This is based on measuring the primary particle energy by determining the angular distribution of secondaries produced in a target layer using silicon microstrip detector technology. The proposed technique can be used over a wide range of energies (10 (exp 11)- 10 (exp 16) eV) and gives an energy resolution of 60% or better. Based on this technique, a design for a new lightweight instrument with a large aperture (KLEM) will be described.

Adams, J.; Bashindzhagyan, G.; Chilingarian, A.; Drury, L.; Egorov, N.; Golubkov,S.; Korotkova, N.; Panasyuk, M.; Podorozhnyi, D.; Procqureur, J.



An Sp1\\/KLF binding site is important for the activity of a Polycomb group response element from the Drosophila engrailed gene  

Microsoft Academic Search

Polycomb-group response elements (PREs) are DNA elements through which the Polycomb-group (PcG) of transcriptional repressors act. Many of the PcG proteins are associated with two protein complexes that repress gene expression by modifying chro- matin. Both of these protein complexes specifically associate with PREs in vivo, however, it is not known how they are recruited or held at the PRE.

J. Lesley Brown; Daniel J. Grau; Sarah K. DeVido; Judith A. Kassis



Novel Rearrangements in the Staphylococcal Cassette Chromosome Mec Type V Elements of Indian ST772 and ST672 Methicillin Resistant Staphylococcus aureus Strains  

PubMed Central

Staphylococcus aureus is a commensal gram positive bacteria which causes severe and non severe infections in humans and livestock. In India, ST772 is a dominant and ST672 is an emerging clone of Staphylococcus aureus. Both cause serious human diseases, and carry type V SCCmec elements. The objective of this study was to characterize SCCmec type V elements of ST772 and ST672 because the usual PCR methods did not amplify all primers specific to the type. Whole genome sequencing analysis of seven ST772 and one ST672 S. aureus isolates revealed that the SCCmec elements of six of the ST772 isolates were the smallest of the extant type V elements and in addition have several other novel features. Only one ST772 isolate and the ST672 isolate carried bigger SCCmec cassettes which were composites carrying multiple ccrC genes. These cassettes had some similarities to type V SCCmec element from M013 isolate (ST59) from Taiwan in certain aspects. SCCmec elements of all Indian isolates had an inversion of the mec complex, similar to the bovine SCCmec type X. This study reveals that six out of seven ST772 S. aureus isolates have a novel type V (5C2) SCCmec element while one each of ST772 and ST672 isolates have a composite SCCmec type V element (5C2&5) formed by the integration of type V SCCmec into a MSSA carrying a SCC element, in addition to the mec gene complex inversions and extensive recombinations. PMID:24722327

Arakere, Gayathri



Element distribution patterns in the ordovician Galena group, Southeastern Minnesota: Indicators of fluid flow and provenance of terrigenous material  

USGS Publications Warehouse

As part of a regional geochemical investigation of lower Paleozoic strata in the Hollandale embayment of southeastern Minnesota, elemental concentrations in acid-insoluble residues were determined for carbonate rock in the Middle Ordovician Galena Group. Elemental distribution patterns within the insoluble residues, particularly those of Ti, Al, and Zr, show that the Wisconsin dome and the Wisconsin arch, which contributed sediment to the embayment prior to Galena time, continued as weak sources of sediment during this period. In contrast, trace metals commonly associated with Mississippi Valley-type lead-zinc mineralization, including Pb, Zn, Cu, Ag, Ni, Co, As, and Mo, show dispersal patterns that are independent of those associated with primary depositional phenomena. These trace metals are concentrated in southern Minnesota in carbonate rocks near the interface between limestone- and dolostone-dominated strata. Dispersal patterns imply that the metals were carried by a north-flowing regional ground-water system. The results show that the geochemical attributes of insoluble residues can be used to distinguish provenance and transport directions of primary sediments within a depositional basin from effects of subsequent regional ground-water flow systems.

Lively, R.S.; Morey, G.B.; Mossler, J.H.



Partitioning of platinum-group elements and Au between sulfide liquid and basalt and the origins of mantle-crust fractionation of the chalcophile elements  

NASA Astrophysics Data System (ADS)

The partitioning of platinum-group elements (PGE; Os, Ir, Ru, Rh, Pt, and Pd) and Au between sulfide melt and silicate melt (i.e., DPGEsul) exerts a critical control on the PGE composition of the Earth’s crust and mantle, but previous estimates have been plagued by experimental uncertainties and vary through several orders of magnitude. Here we present direct experimental measurements of DPGEsul, based on in situ microanalysis of the sulfide and silicate melt, with values ranging from ?4 × 105 (Ru) to ?2-3 × 106 (Ir, Pt). Our measurements of DPGEsul are >100 times larger than previous results but smaller than anticipated based on comparison of alloy solubilities in sulfide melts and S-free silicate melts. The presence of S in the silicate melt greatly increases alloy solubility. We use our new set of partition coefficients to develop a fully constrained model of PGE behavior during melting which accurately predicts the abundances of PGE in mantle-derived magmas and their restites, including mid-ocean ridge basalts, continental picrites, and the parental magmas of the Bushveld Complex of South Africa. Our model constrains mid-ocean ridge basalt (MORB) to be the products of pooled low and high degree fractional melts. Within-plate picrites are pooled products of larger degrees of fractional melting in columnar melting regimes. A significant control on PGE fractionation in mantle-derived magmas is exerted by residual alloy or platinum group minerals in their source. At low pressures (e.g., MORB genesis) the mantle residual to partial melting retains primitive mantle inter-element ratios and abundances of PGE until sulfide has been completely dissolved but then evolves to extremely high Pt/Pd and low Pd/Ir because Pt and Ir alloys form in the restite. During melting at high pressure to form picrites or komatiites Ir alloy appears as a restite phase but Pt alloy is not stable due to the large effect of pressure on fS2, and of temperature on fO2 along an internal oxygen buffer, which causes large increases in alloy solubility. The magmas parental to the Bushveld Complex of South Africa appear, at least in part, to be partial melts of mantle that has previously been melted to the point of total sulfide exhaustion at low pressure, closely resembling mantle xenoliths of the Kaapvaal craton. Using the new extremely large DPGEsul the world-class Merensky Reef and UG2 Pt deposits of the Bushveld Complex can readily be modeled as the result of sulfide saturation due to mixing of magmas with unremarkable PGE contents, obviating the need to postulate anomalously PGE-rich parent magmas or hydrothermal inputs to the deposits.

Mungall, James E.; Brenan, James M.



Elemental content from 0 to 500 keV neutrons: Lunar Prospector results  

Microsoft Academic Search

Neutron spectroscopy is a new way to study planetary bodies that have sufficiently thin atmospheres. This technique was demonstrated for the first time with Lunar Prospector around the Moon. Here, we report results for moderated neutrons having energies from 0 to 500keV that were measured using the anti-coincidence shield (ACS) of the gamma-ray spectrometer. We describe the detection method, followed

I. Genetay; S. Maurice; W. C. Feldman; O. Gasnault; D. J. Lawrence; R. C. Elphic; C. d'Uston; A. B. Binder



Structural and Energetic Analysis of Group V Impurities in p-Type HgCdTe: The Case of As and Sb  

NASA Astrophysics Data System (ADS)

Although molecular beam epitaxy technology-based arsenic-doped Hg1- x Cd x Te has been extensively studied, according to the newly proposed framework of the defect-complex-based p-type doping mechanism, heavier group V elements such as antimony (Sb) should have a different doping behavior because of their larger radius which can cause larger lattice distortion. In this work, we performed first-principles calculations and took As and Sb as examples to study this issue. The substitutional doping, interstitial doping (including split, tetrahedral, and hexagonal interstitial sites), and defect complex doping forms for arsenic and antimony are all investigated. A significant lattice distortion is found in hexagonal and split-site interstitial-Sb-doped Hg0.75Cd0.25Te due to the larger covalent radius of Sb. Compared with As, Sb can lead to a more complicated configuration change in the case of SbHg- V Hg-SbHg tridoping, and the interstitial Sb is found to be stable even with the coupling of Hg vacancies through detailed energetic calculations, indicating that the interstitial Sb has greater ability to form stable defect complexes, and thus great potential to be a more appropriate p-type dopant. This study provides more complementary understanding of the behaviors of group V impurities in HgCdTe.

Wang, Ziyan; Huang, Yan; Lei, Wen; Chen, Xiaoshuang; Zhao, Huxian; Zhou, Xiaohao; Lu, Wei



Subgroup Lattice If G is a group, then its subgroup lattice, L(G) = (V, E), is defined as follows  

E-print Network

Subgroup Lattice If G is a group, then its subgroup lattice, L(G) = (V, E), is defined as follows: The vertex set V is composed of all distinct subgroups H in G. If |H| is a product of exactly i primes, then H is in level i of L(G), denoted H L(i)(G). Suppose H L(i)(G) and K L(j)(G) where j > i. Then {H


Fragmentation Cross Sections of 290 and 400 MeV/nucleon 12C Beamson Elemental Targets  

SciTech Connect

Charge-changing and fragment production cross sections at 0circ have been obtained for interactions of 290 MeV/nucleon and 400MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. Thesebeams are relevant to cancer therapy, space radiation, and the productionof radioactive beams. We compare to previously published results using Cand CH2 targets at similar beam energies. Due to ambiguities arising fromthe presence of multiple fragments on many events, previous publicationshave reported only cross sections for B and Be fragments. In this work wehave extracted cross sections for all fragment species, using dataobtained at three distinct values of angular acceptance, supplemented bydata taken with the detector stack placed off the beam axis. A simulationof the experiment with the PHITS Monte Carlo code shows fair agreementwith the data obtained with the large acceptance detectors, but agreementis poor at small acceptance. The measured cross sections are alsocompared to the predictions of the one-dimensional cross section modelsEPAX2 and NUCFRG2; the latter is presently used in NASA's space radiationtransport calculations. Though PHITS and NUCFRG2 reproduce thecharge-changing cross sections with reasonable accuracy, none of themodels is able to accurately predict the fragment cross sections for allfragment species and target materials.

Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura,A.; Iwata, Y.; Murakami, T.



If G is a group and x, y G then it is not necessarily true that xy = yx. If x and y do satisfy this condition we say that they commute. For example, the elements (1, 2)  

E-print Network

, in any group G, all possible bracketings of a product of several factors yield the same element satisfy this condition we say that they commute. For example, the elements (1, 2) and (1, 3) in the group Sym(3) do not commute, whereas the elements (1, 2)(3, 4) and (1, 3)(2, 4) in the group Sym(4) do

Howlett, Robert Brian


Hyperinfectivity: A Critical Element in the Ability of V. cholerae to Cause Epidemics?  

PubMed Central

Background Cholera is an ancient disease that continues to cause epidemic and pandemic disease despite ongoing efforts to limit its spread. Mathematical models provide one means of assessing the utility of various proposed interventions. However, cholera models that have been developed to date have had limitations, suggesting that there are basic elements of cholera transmission that we still do not understand. Methods and Findings Recent laboratory findings suggest that passage of Vibrio cholerae O1 Inaba El Tor through the gastrointestinal tract results in a short-lived, hyperinfectious state of the organism that decays in a matter of hours into a state of lower infectiousness. Incorporation of this hyperinfectious state into our disease model provides a much better fit with the observed epidemic pattern of cholera. These findings help to substantiate the clinical relevance of laboratory observations regarding the hyperinfectious state, and underscore the critical importance of human-to-human versus environment-to-human transmission in the generation of epidemic and pandemic disease. Conclusions To have maximal impact on limiting epidemic spread of cholera, interventions should be targeted toward minimizing risk of transmission of the short-lived, hyperinfectious form of toxigenic Vibrio cholerae. The possibility of comparable hyperinfectious states in other major epidemic diseases also needs to be evaluated and, as appropriate, incorporated into models of disease prevention. PMID:16318414

Hartley, David M; Morris, J. Glenn; Smith, David L



Platinum-group elements in the Eastern Deccan volcanic province and a comparison with platinum metals of the western Deccan  

NASA Astrophysics Data System (ADS)

This study is the first detailed investigation of the platinum-group elements (PGE) at the eastern margin of the Deccan volcanic province of India. One of the PGE, osmium, is not included largely because of analytical problems. The study is focused on mafic volcanics and dykes from four areas including Amarkantak, Umaria, Shahdol and Chirimiri. The first two localities represent two lava piles of about 170 and 400 m thickness respectively. In Umaria, 16 flows have been demarcated based on petrography and field studies. The Shahdol samples are basal lava formations overlying Gondwana sediments (Carboniferous) and the Chirimiri samples are dykes. In this study, the western Deccan province is defined as the Western Ghats plus Kutch. On average, the PGE are ~20% higher in Amarkantak than Umaria and the flows are ~13% higher in PGE than the dykes. A Zr vs. Pd scattergram found a strong positive correlation for these two elements except for one Umaria sample which indicated severe Pd loss. A comparison of west and east parts of the Deccan volcanic province using primitive mantle normalization showed that higher values prevailed in the western province suite in the Ni-Ir-Ru-Pt region. In contrast, eastern province values dominated in the Pd-Au-Cu region at the `Cu' end of the profiles. A strong dominance of Pd in the eastern Deccan was also of interest. A number of factors, for example, percentage partial melting of the source rock and the temperature and pressure of partial melting strongly influence the character of these profiles. The observed PGE profile characteristics probably result in part from a long distance of subsurface transport of Deccan magma from the western to eastern regions.

Crocket, James; Paul, Dalim; Lala, Trisha



A three-dimensional finite element algorithm for prediction of V/STOL jet-induced flowfields  

NASA Astrophysics Data System (ADS)

A three dimensional mathematical model of the basic V/STOL jet, and the flow in the associated near field using a formal order of magnitude analysis was constructed. This produces a parabolized approximation to the steady, time averaged, three dimensional Navier-Stokes equations for a turbulent subsonic flow. A continuity constraint finite element numerical solution algorithm is identified, which independently enforces ordered phenomena for solution of the equation system including transport equations for turbulence kinetic energy and dissipation parameters. The numerical solution of the established equation system yields prediction of core vortex roll up, far field deflection of the cross flow, near field entrainment of the cross flow into the jet, and wake flow reversal with additional entrainment into the jet core. The primary causal mechanism is computationally assessed to be the turbulence interaction on the upstream face of the jet, as verified by results from a range of computational experiments.

Baker, A. J.; Manhardt, P. D.; Orzxechowski, J. A.; Yen, K. T.



"Aegean Seals of the Late Bronze Age: Stylistic Groups, V. Minoan Groups Contemporary with LM IIIA1"  

E-print Network

of Texr I. The Spectacle-Eye Group (p. 121) A. Thin Faces, no dottcd lowcr jarv B. One or two small dots on thc jowl C. One large dot on the jowl D. Mumps, several large dots on the jowl E. Swollen jowl, no dots F. Frontal faces with spectacle eyes G..., Ta Sphragisrrata t()n Khrniorr ([Sibliotirctic tcs cn Athcnris Arclrliolosihcs Hetaircirs no. 7, Athcns lgZZ). l'irri l9fi0 l. l'ini, "l(ypro Agiisclrc I|rllsicgcl,".ll)l 95, I9l.t0, /7 l0ll. t20 Text Nr. I.A1 2 J 4 5 6 7 8 9 10 71 t2 813 14 15 16 18...

Younger, John G.




NSDL National Science Digital Library

This interactive Flash applet models the measurement interpretation of division. A child or teacher chooses a total number of objects and a divisor representing the size of equal groups. The applet allows the user to move the objects into equal groups and links the process to jumps on a number line. The applet can be used to introduce children to remainders and to reinforce the language and notation of division. It works well on an interactive white board or projector. A teacher's guide to this collection of applets is cataloged separately.



Volatile Elements Production Rates in a 1.4-GeV Proton-Irradiated Molten Lead-Bismuth Target  

SciTech Connect

Production rates of volatile elements following the spallation reaction of 1.4-GeV protons on a liquid Pb/Bi target have been measured. The experiment was performed at the ISOLDE facility at CERN. These data are of interest for the development of targets for accelerator-driven systems such as MEGAPIE. Additional data have been taken on a liquid Pb target. Calculations were performed using the FLUKA and MCNPX Monte Carlo codes coupled with the evolution codes ORIHET3 and FISPACT using different options for the intra-nuclear cascades and evaporation models. Preliminary results from the data analysis show good comparison with calculations for Hg and for noble gases. For other elements such as I, it is apparent that only a fraction of the produced isotopes is released. The agreement with the experimental data varies depending on the model combination used. The best results are obtained using MCNPX with the INCL4/ABLA models and with FLUKA. Discrepancies are found for some isotopes produced by fission using the MCNPX with the Bertini intranuclear cascade model coupled with the Dresner evaporation model.

Zanini, L.; Andersson, M.; Groeschel, F.; Lebenhaft, J.; Manfrin, E.; Wagner, W.; Wohlmuther, M. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Everaerts, P.; Koester, U.; Ravn, H. [CERN, CH-1211 Geneva (Switzerland); Fallot, M.; Kirchner, T.; Tall, Y. [SUBATECH, 44307 Nantes-cedex 3 (France); Fraanberg, H. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); CERN, CH-1211 Geneva (Switzerland); Jost, C. [Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Kojima, Y. [Hiroshima University, 1-4-1-Higashi-Hiroshima 7398527 (Japan); Pitcher, E. [Los Alamos National Laboratory, Los Alamos NM 87545 (United States)



Volatile Elements Production Rates in a 1.4-GeV Proton-Irradiated Molten Lead-Bismuth Target  

NASA Astrophysics Data System (ADS)

Production rates of volatile elements following the spallation reaction of 1.4-GeV protons on a liquid Pb/Bi target have been measured. The experiment was performed at the ISOLDE facility at CERN. These data are of interest for the development of targets for accelerator-driven systems such as MEGAPIE. Additional data have been taken on a liquid Pb target. Calculations were performed using the FLUKA and MCNPX Monte Carlo codes coupled with the evolution codes ORIHET3 and FISPACT using different options for the intra-nuclear cascades and evaporation models. Preliminary results from the data analysis show good comparison with calculations for Hg and for noble gases. For other elements such as I, it is apparent that only a fraction of the produced isotopes is released. The agreement with the experimental data varies depending on the model combination used. The best results are obtained using MCNPX with the INCL4/ABLA models and with FLUKA. Discrepancies are found for some isotopes produced by fission using the MCNPX with the Bertini intranuclear cascade model coupled with the Dresner evaporation model.

Zanini, L.; Andersson, M.; Everaerts, P.; Fallot, M.; Frânberg, H.; Gröschel, F.; Jost, C.; Kirchner, T.; Kojima, Y.; Köster, U.; Lebenhaft, J.; Manfrin, E.; Pitcher, E.; Ravn, H.; Tall, Y.; Wagner, W.; Wohlmuther, M.



A correlation between solid solubility and tetrahedral radius of III, IV and V group impurities in silicon  

Microsoft Academic Search

The strain entropy of substitutional Group III, IV and V impurities in silicon has been calculated from the experimental solid solubility taking into account the electronic, vibrational and polarization contributions. A correlation between differences of tetrahedral radii and strain entropy is found.Silicon is perhaps the most studied substance after water. In spite of this, there is, at present, no unified

P. Cappelletti; G. F. Cerofolini; G. U. Pignatel



Localization of Group V Phospholipase A2 in Caveolin-enriched Granules in Activated P388D1 Macrophage-like Cells*  

E-print Network

stimulation by lipopolysaccharide involves the action of Group V secreted phospholipase A2 (PLA2), Group IV cytosolic PLA2 (cPLA2), and cyclooxygenase-2 (COX-2). There is an initial activation of cPLA2 that induces expression of Group V PLA2, which in turn induces both the expres- sion of COX-2 and most of the arachidonic

Dennis, Edward A.


BRAF-V600E expression in precursor versus differentiated dendritic cells defines clinically distinct LCH risk groups  

PubMed Central

Langerhans cell histiocytosis (LCH) is a clonal disorder with elusive etiology, characterized by the accumulation of CD207+ dendritic cells (DCs) in inflammatory lesions. Recurrent BRAF-V600E mutations have been reported in LCH. In this study, lesions from 100 patients were genotyped, and 64% carried the BRAF-V600E mutation within infiltrating CD207+ DCs. BRAF-V600E expression in tissue DCs did not define specific clinical risk groups but was associated with increased risk of recurrence. Strikingly, we found that patients with active, high-risk LCH also carried BRAF-V600E in circulating CD11c+ and CD14+ fractions and in bone marrow (BM) CD34+ hematopoietic cell progenitors, whereas the mutation was restricted to lesional CD207+ DC in low-risk LCH patients. Importantly, BRAF-V600E expression in DCs was sufficient to drive LCH-like disease in mice. Consistent with our findings in humans, expression of BRAF-V600E in BM DC progenitors recapitulated many features of the human high-risk LCH, whereas BRAF-V600E expression in differentiated DCs more closely resembled low-risk LCH. We therefore propose classification of LCH as a myeloid neoplasia and hypothesize that high-risk LCH arises from somatic mutation of a hematopoietic progenitor, whereas low-risk disease arises from somatic mutation of tissue-restricted precursor DCs. PMID:24638167

Berres, Marie-Luise; Lim, Karen Phaik Har; Peters, Tricia; Price, Jeremy; Takizawa, Hitoshi; Salmon, Helene; Idoyaga, Juliana; Ruzo, Albert; Lupo, Philip J.; Hicks, M. John; Shih, Albert; Simko, Stephen J.; Abhyankar, Harshal; Chakraborty, Rikhia; Leboeuf, Marylene; Beltrao, Monique; Lira, Sergio A.; Heym, Kenneth M.; Bigley, Venetia; Collin, Matthew; Manz, Markus G.; McClain, Kenneth



Ancient mantle trapped in the Mariana arc-basin system: Insights from the platinum group elements and Os isotopes  

NASA Astrophysics Data System (ADS)

Serpentinized harzburgites recently drilled during ODP Leg 195 at South Chamorro Seamount in the Mariana forearc region have been studied for their platinum group element (PGE) concentrations and Os isotopic compositions. The samples allow a look at the slab fluid-modified subarc mantle immediately overlaying the actively subducting Pacific slab at depths of ~ 30 km. The average PGE (Os 2.3 ppb, Ir 1.5 ppb, Ru 5.4 ppb, Pd 1.6 ppb and Pt 16.3 ppb) and Re (60 ppt) abundances are comparable to those measured in other subarc mantle xenolith suites. The PGE and Re abundances are depleted up to 3 orders of magnitude relative to chondrites, with relative order of depletions Ru > Os > Ir> Pt> Re> Pd. The variable Pd contents (0.01-4.5 ppb) and the low Pd/Os (<2) in the Mariana forearc samples differ significantly from that of altered oceanic crust (Pd/Os~ 22), suggesting Os remained relatively unchanged during low temperature subduction-fluid additions. Serpentinitization of the harzburgites occurred in equilibrium with fluids that were both reducing and highly alkaline. Os in its original phases may be stabilized in such an environment, therefore can preserve evidence for ancient melting despite later slab interactions. Finally, the high Pt/Pd (ave. ~ 25) and low Re contents (ave.~ 60 ppt) in the Leg 195 forearc samples are complementary to those measured in boninites from the Izu-Bonin-Mariana arc-basin system, showing a genetic relationship. Our samples reveal an average 187Os/188Os of 0.123 [range = 0.119- 0.127], making them similar to abyssal peridotites from elsewhere. Radiogenic 187Os/188Os ratios would have been imparted to the serpentinites by slab fluids, so the subchondritic Os isotopic compositions implies that peridotite-slab fluid interactions did not alter the Os isotope systematics of the mantle protoliths. Low alumina abundances (<1 %) and trace element signatures (low HFSE; REE with U-shaped chondrite-normalized patterns and 2-3 times lower than chondrite meteorite abundances) imply that the serpentinites are highly melt-depleted. Depleted mantle model ages calculated from the Os isotopic compositions span the range from several million to more than billion years as was shown for other Mariana subarc mantle samples recovered ~ 1000 km to the north at Conical Seamount [Parkinson et al., Science, 1998]. The dramatic age variations and the trace element and isotope systematics in the subarc mantle of the Marianas reveal that 55 M.y. of active plate convergence in the Western Pacific did not entirely recycle the pre-subduction mantle. We suggest that remnants of old mantle remain trapped as small "plum"- like domains in the region between the Mariana Trench and the Mariana volcanic front.

Savov, I. P.; Shirey, S. B.; Horan, M. F.; Mock, T. D.



Transcription from a murine T-cell receptor V beta promoter depends on a conserved decamer motif similar to the cyclic AMP response element.  

PubMed Central

We identified a regulatory region of the murine V beta promoter by both in vivo and in vitro analyses. The results of transient transfection assays indicated that the dominant transcription-activating element within the V beta 8.3 promoter is the palindromic motif identified previously as the conserved V beta decamer. Elimination of this element, by linear deletion or specific mutation, reduced transcriptional activity from this promoter by 10-fold. DNase I footprinting, gel mobility shift, and methylation interference assays confirmed that the palindrome acts as the binding site of a specific nuclear factor. In particular, the V beta promoter motif functioned in vitro as a high-affinity site for a previously characterized transcription activator, ATF. A consensus cyclic AMP response element (CRE) but not a consensus AP-1 site, can substitute for the decamer in vivo. These data suggest that cyclic AMP response element-binding protein (ATF/CREB) or related proteins activate V beta transcription. Images PMID:2557542

Anderson, S J; Miyake, S; Loh, D Y



The coupling of thermochemistry and phase diagrams for group III-V semiconductor systems. Final report  

SciTech Connect

The project was directed at linking the thermochemical properties of III-V compound semiconductors systems with the reported phase diagrams. The solid-liquid phase equilibrium problem was formulated and three approaches to calculating the reduced standard state chemical potential were identified and values were calculated. In addition, thermochemical values for critical properties were measured using solid state electrochemical techniques. These values, along with the standard state chemical potentials and other available thermochemical and phase diagram data, were combined with a critical assessment of selected III-V systems. This work was culminated with a comprehensive assessment of all the III-V binary systems. A novel aspect of the experimental part of this project was the demonstration of the use of a liquid encapsulate to measure component activities by a solid state emf technique in liquid III-V systems that exhibit high vapor pressures at the measurement temperature.

Anderson, T.J.



Structure of the type IX group B Streptococcus capsular polysaccharide and its evolutionary relationship with types V and VII.  


The Group B Streptococcus capsular polysaccharide type IX was isolated and purified, and the structure of its repeating unit was determined. Type IX capsule ? 4)[NeupNAc-?-(2 ? 3)-Galp-?-(1 ? 4)-GlcpNAc-?-(1 ? 6)]-?-GlcpNAc-(1 ? 4)-?-Galp-(1 ? 4)-?-Glcp-(1 ? appears most similar to types VII and V, although it contains two GlcpNAc residues. Genetic analysis identified differences in cpsM, cpsO, and cpsI gene sequences as responsible for the differentiation between the three capsular polysaccharide types, leading us to hypothesize that type V emerged from a recombination event in a type IX background. PMID:24990951

Berti, Francesco; Campisi, Edmondo; Toniolo, Chiara; Morelli, Laura; Crotti, Stefano; Rosini, Roberto; Romano, Maria Rosaria; Pinto, Vittoria; Brogioni, Barbara; Torricelli, Giulia; Janulczyk, Robert; Grandi, Guido; Margarit, Immaculada



Thermodynamic calculations of the volatility of the platinum group elements (PGE): The PGE content of fluids at magmatic temperatures  

SciTech Connect

The volatilities of the platinum-group elements as metals, oxides and chlorides were calculated at temperatures of 800-1600 K. Only Pd is significantly volatile as the metal. At log f{sub H{sub 2}O} = 1 Kbar and 1200 K, the concentration (weight) of Pd in the vapor reaches 1 ppt and at 1600 K attains several ppb. The PGE oxides are extremely volatile at atmospheric oxygen fugacities. However, only Os and Ru have significant volatilities ({>=} 1 ppt) as oxides (OsO{sub 4}, RuO{sub 3}) at oxygen fugacities typical of magmatic PGE deposits (near QFM), and only at temperatures greater than 1400 K. Data on the volatility of PGE chlorides exist only for Pd and Ru, both of which are somewhat more volatile as chlorides than as oxides. At 1400 K, f{sub H{sub 2}O} = 1000 bars, f{sub HCl} = 100 bars and at QFM, the calculated vapor concentrations of PdCl{sub 2} and RuCl{sub 3} are 500 ppt and 20 ppt, respectively. However, higher concentrations of PGE may be attained at higher temperatures, higher f{sub O{sub 2}}, higher f{sub HCl} or lower f{sub H{sub 2}O}. Also, any interactions between water vapor and PGE vapor species would tend to increase the vapor concentration of PGE. Vapor transport of the more volatile PGE as chlorides may play some role in the transport of these metals in mafic igneous complexes such as the Stillwater or the Bushveld. However, under the conditions where the PGE are most volatile, the metals Fe, Ni and Cu are several factors of ten more volatile, so that enrichment of the PGe and Cu over Ni and Fe cannot be explained by chloride transport alone.

Wood, S.A. (McGill Univ., Montreal, Quebec (Canada))



Platinum-group elements (Rh, Pt, Pd) and Au distribution in snow samples from the Kola Peninsula, NW Russia  

NASA Astrophysics Data System (ADS)

In April 1996 snowpack samples were collected from the surroundings of the ore roasting and dressing plant at Zapoljarnij and the nickel smelters at Nikel and Monchegorsk, Kola Peninsula, NW Russia. In the laboratory, filter residues of snowpack samples (fraction>0.45 ?m) from 15 localities (close to the nickel processing centres) were chemically for precious metals (Rh, Pt, Pd, Au) and Te by graphite furnace atomic absorption spectrometry (GFAAS) analysis, and for Cu and Ni by ICP-MS. Values up to 2770 ng/l Pd, 650 ng/l Pt and 186 ng/l Au were found in the filter residues. Additionally, platinum-group elements (PGE) and Au contents in ore samples from Noril'sk , as well as in technogenic products ("Cu-Ni-feinstein" and copper concentrate) processed at the Monchegorsk smelter complex, were analysed using flameless atomic absorption spectroscopy (FAAS) for comparison with results obtained from snow. Rh, Pt, Pd and Au distribution data show the presence of two ore components (Noril'sk and Pechenga). Concentrations of these metals decrease with distance from the industrial sources and with the prevailing wind direction (generally north-south). Microscopic investigations and electron microprobe analysis of polished sections of snow filter residues (>0.45 ?m) also reveal differences between particles from the two sources. To avoid confusion the term "Noril'sk" is used throughout the paper to denote material and/or data from the Noril'sk area and its sub-district, Noril'sk while Pechenga relates to the local ore.

Gregurek, Dean; Melcher, Frank; Niskavaara, Heikki; Pavlov, Vladimir A.; Reimann, Clemens; Stumpfl, Eugen F.


Report of the IAU\\/IAG\\/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 1994  

Microsoft Academic Search

Every three years the IAU\\/IAG\\/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Stallites revises tables giving the directions of the north poles of rotation and the prime meridians of the planets, satellites, and asteroids. Also presented are revised tables giving their sizes and shapes.

M. E. Davies; V. K. Abalakin; M. Bursa; J. H. Lieske; B. Morando; D. Morrison; P. K. Seidelmann; A. T. Sinclair; B. Yallop; Y. S. Tjuflin



(sup 187)Re-(sup 187)Os(sup 190)Pt-(sup 186)Os Isotopic and Highly Sideophile Element Systematics of Group IVA Irons.  

National Technical Information Service (NTIS)

We have recently completed (sup 187)Re-(sup 187)Os and (sup 190)Pt-(sup 186)Os isotopic and elemental studies of the two largest magmatic iron meteorite groups, IIAB and IIIAB. These studies revealed closed-system behavior of both isotopic systems, but co...

R. J. Walker, T. J. McCoy



A Divergent P Element and Its Associated MITE, BuT5, Generate Chromosomal Inversions and Are Widespread within the Drosophila repleta Species Group  

PubMed Central

The transposon BuT5 caused two chromosomal inversions fixed in two Drosophila species of the repleta group, D. mojavensis and D. uniseta. BuT5 copies are approximately 1-kb long, lack any coding capacity, and do not resemble any other transposable element (TE). Because of its elusive features, BuT5 has remained unclassified to date. To fully characterize BuT5, we carried out bioinformatic similarity searches in available sequenced genomes, including 21 Drosophila species. Significant hits were only recovered for D. mojavensis genome, where 48 copies were retrieved, 22 of them approximately 1-kb long. Polymerase chain reaction (PCR) and dot blot analyses on 54 Drosophila species showed that BuT5 is homogeneous in size and has a widespread distribution within the repleta group. Thus, BuT5 can be considered as a miniature inverted-repeat TE. A detailed analysis of the BuT5 hits in D. mojavensis revealed three partial copies of a transposon with ends very similar to BuT5 and a P-element-like transposase-encoding region in between. A putatively autonomous copy of this P element was isolated by PCR from D. buzzatii. This copy is 3,386-bp long and possesses a seven-exon gene coding for an 822-aa transposase. Exon–intron boundaries were confirmed by reverse transcriptase-PCR experiments. A phylogenetic tree built with insect P superfamily transposases showed that the D. buzzatii P element belongs to an early diverging lineage within the P-element family. This divergent P element is likely the master transposon mobilizing BuT5. The BuT5/P element partnership probably dates back approximately 16 Ma and is the ultimate responsible for the generation of the two chromosomal inversions in the Drosophila repleta species group. PMID:23682154

Rius, Nuria; Delprat, Alejandra; Ruiz, Alfredo



Trace element (Al, As, B, Ba, Cr, Mo, Ni, Se, Sr, Tl, U and V) distribution and seasonality in compartments of the seagrass Cymodocea nodosa.  


Novel information on the biological fate of trace elements in seagrass ecosystems is provided. Al, As, B, Ba, Cr, Mo, Ni, Se, Sr, Tl, U and V concentrations in five compartments (blades, sheaths, vertical rhizomes, main axis plus additional branches, roots) of the seagrass Cymodocea nodosa, as well as in seawater and sediments from the Thessaloniki Gulf, Greece were determined monthly. Uni- and multivariate data analyses were applied. Leaf compartments and roots displayed higher Al, Mo, Ni and Se annual mean concentrations than rhizomes, B was highly accumulated in blades and Cr in sheaths; As, Ba, Sr and Tl contents did not significantly vary among plant compartments. A review summarizing reported element concentrations in seagrasses has revealed that C. nodosa sheaths display a high Cr accumulation capacity. Most element concentrations in blades increased in early mid-summer and early autumn with blade size and age, while those in sheaths peaked in late spring-early summer and autumn when sheath size was the lowest; elevated element concentrations in seawater in late spring and early-mid autumn, possibly as a result of elevated rainfall and associated run-off from the land, may have also contributed to the observed variability. Element concentrations in rhizomes and roots generally displayed a temporary increase in late autumn, which was concurrent with high rainfall, low wind speed associated with reduced hydrodynamism, and elevated sediment element levels. The bioaccumulation factor based on element concentrations in seagrass compartments and sediments was lower than 1 except for B, Ba, Mo, Se and Sr in all compartments, Cr in sheaths and U in roots. Blade V concentration positively correlated with sediment V concentration, suggesting that C. nodosa could be regarded as a bioindicator for V. Our findings can contribute to the design of biomonitoring programs and the development of predictive models for rational management of seagrass meadows. PMID:23838054

Malea, Paraskevi; Kevrekidis, Theodoros



Perdomo v. Holder: The Continuing Struggle to Define the Concept of a Particular Social Group  

Microsoft Academic Search

Qualifying for asylum requires that an applicant be considered a refugee. In order to qualify, an applicant bears the burden of demonstrating persecution or a well-founded fear of persecution on the basis of race, religion, nationality, political opinion, or membership in a particular social group. Often, gender-based asylum claims can only proceed under the particular social group category. The Ninth

Corey Sullivan Martin



New clues on outburst mechanisms and improved spectroscopic elements of the black-hole binary V4641 Sagittarii  

E-print Network

We present spectroscopic observations of the black-hole binary V4641 Sagittarii, obtained between 4th July 2004 and 28th March 2005, which cover the minor outburst of the star in early July 2004 and quiescence variations on 19 nights scattered over six months. During the outburst, the star peaked approximately 3 magnitudes brighter than usual, and our spectra were dominated by broad hydrogen, helium and iron emission lines. The very first spectra showed P Cygni profiles, which disappeared within a few hours, indicating rapid changes in matter ejection. The H-alpha line had multiple components, one being a broad blue-shifted wing exceeding 5000 km/s. During a simultaneously observed 10-min photometric flare-up, the equivalent width of the H-alpha line temporarily decreased, implying that it was a flare of the continuum. The overall spectral appearance was similar to that observed in the 1999 September active phase, which suggests that similar mass-ejection processes were associated with both eruptions. In quiescence, the spectra were those of the early-type secondary star showing its orbital motion around the primary. By measuring cross-correlation radial velocities, we give an improved set of spectroscopic elements. Whereas we measure the same velocity amplitude (K_2=211.3+/-1.0 km/s), within errors, as Orosz et al. (2001), our centre-of-mass velocity (v_gamma=72.7+/-3.3 km/s) differs significantly from the previously published value (107.4+/-m2.9 km/s). However, we find evidence that the difference is caused by a systematic error in data reduction in the previous study, rather than by gravitational effects of an invisible third component.

C. Lindstrom; J. Griffin; L. L. Kiss; M. Uemura; A. Derekas; Sz. Meszaros; P. Szekely



Expression of ABO blood-group genes is dependent upon an erythroid cell-specific regulatory element that is deleted in persons with the B(m) phenotype.  


The ABO blood group is of great importance in blood transfusion and organ transplantation. However, the mechanisms regulating human ABO gene expression remain obscure. On the basis of DNase I-hypersensitive sites in and upstream of ABO in K562 cells, in the present study, we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays indicated a novel positive regulatory element in intron 1. This element was shown to enhance ABO promoter activity in an erythroid cell-specific manner. Electrophoretic mobility-shift assays demonstrated that it bound to the tissue-restricted transcription factor GATA-1. Mutation of the GATA motifs to abrogate binding of this factor reduced the regulatory activity of the element. Therefore, GATA-1 appears to be involved in the cell-specific activity of the element. Furthermore, we found that a partial deletion in intron 1 involving the element was associated with B(m) phenotypes. Therefore, it is plausible that deletion of the erythroid cell-specific regulatory element could down-regulate transcription in the B(m) allele, leading to reduction of B-antigen expression in cells of erythroid lineage, but not in mucus-secreting cells. These results support the contention that the enhancer-like element in intron 1 of ABO has a significant function in erythroid cells. PMID:22408256

Sano, Rie; Nakajima, Tamiko; Takahashi, Keiko; Kubo, Rieko; Kominato, Yoshihiko; Tsukada, Junichi; Takeshita, Haruo; Yasuda, Toshihiro; Ito, Kazuto; Maruhashi, Takayuki; Yokohama, Akihiko; Isa, Kazumi; Ogasawara, Kenichi; Uchikawa, Makoto



VEGF stimulation of endothelial cell PAF synthesis is mediated by group V 14 kDa secretory phospholipase A2  

E-print Network

A-IT; phospholipase A2, PLA2; and lyso-PAF acetyltransferase, lyso-PAF-AT) may participate in PAF synthesis, we®rming the crucial role of the PLA2 and lyso-PAF-AT. 4 Treatment with secreted PLA2 (sPLA2) inhibitors which have been shown to inhibit both groups IIA and V sPLA2 (SB203347; 10 mM and LY311727; 100 mM) blocked EC PAF

Dennis, Edward A.


Comparison of MOVPE grown GaAs solar cells using different substrates and group-V precursors  

Microsoft Academic Search

We have investigated the influence of substrate type (GaAs vs. germanium) and of group-V precursor (AsH3 vs. TBAs) on the epitaxial quality of (In)(Al)GaAs layers. We evaluated these layers in terms of morphology, background contamination and doping characteristics. For final benchmarking of the individually optimised processes, we produced p-on-n single junction GaAs solar cells and compared their relative performance. This

J. Derluyn; K. Dessein; G. Flamand; Y. Mols; J. Poortmans; G. Borghs; I. Moerman



Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report  

SciTech Connect

The work contained herein constitutes a report of the ''Beyond the Standard Model'' working group for the Workshop ''Physics at TeV Colliders'', Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

Allanach, B.C.; /Cambridge U., DAMTP; Grojean, C.; /Saclay, SPhT /CERN; Skands, P.; /Fermilab; Accomando, E.; Azuelos, G.; Baer, H.; Balazs, C.; Belanger, G.; Benakli, K.; Boudjema, F.; Brelier, B.; Bunichev, V.; Cacciapaglia, G.; Carena, M.; Choudhury, D.; Delsart, P.-A.; De Sanctis, U.; Desch, K.; Dobrescu, B.A.; Dudko, L.; El Kacimi, M.; /Saclay,



Tables of X-ray mass attenuation coefficients and mass energy-absorption coefficients 1 keV to 20 MeV for elements Z=1 to 92 and 48 additional substances of dosimetric interest  

Microsoft Academic Search

Tables and graphs of the photon mass attenuation coefficient mu\\/rho and the mass energy-absorption coefficient mu(en)\\/rho are presented for all of the elements Z=1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV. The mu\\/rho values are taken from the

J. H. Hubbell; Stephen M Seltzer



Magnetic model refinement via a coupling of finite element subproblems Patrick Dular1,2, Ruth V. Sabariego1, Laurent Krhenbhl3, Christophe Geuzaine1  

E-print Network

Magnetic model refinement via a coupling of finite element subproblems Patrick Dular1,2, Ruth V will be il- lustrated and validated on various problems. 2. Series of Coupled Subproblems Instead of solving and current densities in stranded inductors. Similar VSs can also express changes of permeabil- ity µ

Boyer, Edmond


Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. I. Electronic structures and properties of MCl4 and MOCl2 (M = Ti, Zr, Hf, and Rf)  

NASA Astrophysics Data System (ADS)

Relativistic, infinite order exact two-component, density functional theory electronic structure calculations were performed for MCl4 and MOCl2 of group-4 elements Ti, Zr, Hf, and element 104, Rf, with the aim to predict their behaviour in gas-phase chromatography experiments. RfCl4 and RfOCl2 were shown to be less stable than their lighter homologs in the group, tetrachlorides and oxychlorides of Zr and Hf, respectively. The oxychlorides turned out to be stable as a bent structure, though the stabilization energy with respect to the flat one (C2v) is very small. The trend in the formation of the tetrachlorides from the oxychlorides in group 4 is shown to be Zr < Hf < Rf, while the one in the formation of the oxychlorides from the chlorides is opposite. All the calculated properties are used to estimate adsorption energy of these species on various surfaces in order to interpret results of gas-phase chromatography experiments, as is shown in Paper II.

Pershina, V.; Borschevsky, A.; Iliaš, M.



Baseline Glutamate Levels Affect Group I and II mGluRs in Layer V Pyramidal Neurons of Rat Sensorimotor Cortex  

E-print Network

Baseline Glutamate Levels Affect Group I and II mGluRs in Layer V Pyramidal Neurons of Rat glutamate levels affect group I and II mGluRs in layer V Pyramidal neurons of rat sensorimotor cortex. J explored. To determine whether this endogenous glutamate acts on metabotropic glutamate receptors (m

Huguenard, John R.


Four-momentum transfer between groups of secondary particles in proton-nucleus interactions at 200 GeV  

SciTech Connect

Data on interactions of 200-GeV protons in nuclear emulsion has been used to determine the lower limit of the four-momentum transfer between groups of secondary particles in jets. It is found that parallel/ in a jet increases linearly with the multiplicity of the jet. All the jets with large multiplicity show clear pronounced maxima in parallel/ plotted against log tan theta/sub L/. The four-momentum transferred between groups of secondary particles produced in the above interactions has been studied to determine the nature of the particle exchanged between these groups. The results are in agreement with the prediction of the Pomeranchuk-pole-exchange model.

Daftari, I.K.; Gupta, V.K.; Kaul, G.L.; Mangotra, L.K.; Prakash, Y.; Rao, N.K.; Sharma, S.K.; Singh, G.; Aggrawal, M.M.



Structural environments of incompatible elements in silicate glass/melt systems: II. U IV, U V, and U VI  

NASA Astrophysics Data System (ADS)

The structural environments of trace to minor levels (?2000 ppm to ?3.0 wt%) of U in several silicate glasses were examined as a function of oxygen fugacity, melt composition, and melt polymerization using X-ray (XANES and EXAFS) and optical absorption spectroscopies. Glass compositions were diopside (CaMgSi 2O 6: DI), anorthite (CaAlSi 2O 8: AN), albite (NaAlSi 3O 8: AB), sodium trisilicate (Na 2Si 3O 7: TS), a peralkaline composition (Na 3.3AlSi 7O 17: PR, approximately halfway between AB and TS), and a calc-alkaline rhyolite composition (RH). A second set of silicate glasses of the same base compositions containing ?2000 ppm to ?3.0 wt% U and ?0.6 to 2.5 wt% F or Cl was also synthesized. In the glasses synthesized under oxidizing conditions (in air), U VI occurs as uranyl groups with two axial oxygens at ? 1.77-1.85 ± 0.02 Å and four to five equatorial oxygens at ?2.21-2.25 ± 0.03 Å. In glasses synthesized under more reducing conditions ( fO2 ? 10 -3-10 -7 atm), U V occurs in moderately distorted 6-coordinated polyhedra [ d(U V-O) ? 2.19-2.24 ± 0.03 Å], which may co-exist with smaller numbers of U VI species and/or U VI species. Under the most reducing conditions used ( fO2 ? 10 -8-10 -12 atm), U IV occurs in less distorted octahedra [ d(U IV-O) ? 2.26-2.29 ± 0.02 Å]. No clear evidence for U-F or U-Cl bonds was found for any of the halogen-containing glasses, suggesting that U-halogen "complexes" are not present. In addition, no U-U (second-neighbor) interactions were detected, indicating that no significant clustering of U atoms is present in any of the glasses studied. Bond strength-bond length calculations and constraints placed on local bonding by Pauling's second rule suggest that U IV and U V in 6-coordinated sites in silicate melts will preferentially bond to nonbridging oxygens (NBO's) rather than bridging oxygens (BO's). The unusually low 6-fold coordination of U IV and U V in relatively depolymerized silicate melts (e.g., peralkaline and halogen-rich melts) results in a high U-O bond strength in the melt that is not observed in crystalline U-bearing minerals. This difference in bond strength is partially responsible for the small crystal-melt partition coefficients of U IV. In addition, the common silicate minerals comprising igneous rocks lack appropriate crystallographic sites which can stably accommodate this large and highly charged cation. These factors help explain the normally incompatible character of U IV during magmatic differentiation. In contrast, the low solubility of U IV and U V in more polymerized silicate melts, such as those produced during the late stages of magmatic differentiation, can be explained by a shortage of NBO's. Increasing amounts of 8-fold coordinated U should favor the incorporation of both U IV and U V in accessory minerals like zircon, thorite, titanite, apatite, uranium oxides, etc., thus its more compatible behavior in the latest stages of magmatic differentiation.

Farges, Franã§Ois; Ponader, Carl W.; Calas, Georges; Brown, Gordon E., Jr.



Upper level and phase controlling group velocity in V-type system  

NASA Astrophysics Data System (ADS)

With the external field coupling the two upper levels, we investigate the light pulse propagation properties with weak probe field in a V-type system. Due to the external upper level (UL) coupling field, the dispersion of the system has been influenced by the relative phase. It is shown that the UL field and the relative phase can be regarded as switches to manipulate light propagation between subluminal and superluminal.

Han, Dingan; Zeng, Yaguang; Bai, Yanfeng



Three groups of transposable elements with contrasting copy number dynamics and host responses in the maize (Zea mays ssp. mays) genome.  


Most angiosperm nuclear DNA is repetitive and derived from silenced transposable elements (TEs). TE silencing requires substantial resources from the plant host, including the production of small interfering RNAs (siRNAs). Thus, the interaction between TEs and siRNAs is a critical aspect of both the function and the evolution of plant genomes. Yet the co-evolutionary dynamics between these two entities remain poorly characterized. Here we studied the organization of TEs within the maize (Zea mays ssp mays) genome, documenting that TEs fall within three groups based on the class and copy numbers. These groups included DNA elements, low copy RNA elements and higher copy RNA elements. The three groups varied statistically in characteristics that included length, location, age, siRNA expression and 24:22 nucleotide (nt) siRNA targeting ratios. In addition, the low copy retroelements encompassed a set of TEs that had previously been shown to decrease expression within a 24 nt siRNA biogenesis mutant (mop1). To investigate the evolutionary dynamics of the three groups, we estimated their abundance in two landraces, one with a genome similar in size to that of the maize reference and the other with a 30% larger genome. For all three accessions, we assessed TE abundance as well as 22 nt and 24 nt siRNA content within leaves. The high copy number retroelements are under targeted similarly by siRNAs among accessions, appear to be born of a rapid bust of activity, and may be currently transpositionally dead or limited. In contrast, the lower copy number group of retrolements are targeted more dynamically and have had a long and ongoing history of transposition in the maize genome. PMID:24743518

Diez, Concepcion M; Meca, Esteban; Tenaillon, Maud I; Gaut, Brandon S



Three Groups of Transposable Elements with Contrasting Copy Number Dynamics and Host Responses in the Maize (Zea mays ssp. mays) Genome  

PubMed Central

Most angiosperm nuclear DNA is repetitive and derived from silenced transposable elements (TEs). TE silencing requires substantial resources from the plant host, including the production of small interfering RNAs (siRNAs). Thus, the interaction between TEs and siRNAs is a critical aspect of both the function and the evolution of plant genomes. Yet the co-evolutionary dynamics between these two entities remain poorly characterized. Here we studied the organization of TEs within the maize (Zea mays ssp mays) genome, documenting that TEs fall within three groups based on the class and copy numbers. These groups included DNA elements, low copy RNA elements and higher copy RNA elements. The three groups varied statistically in characteristics that included length, location, age, siRNA expression and 24?22 nucleotide (nt) siRNA targeting ratios. In addition, the low copy retroelements encompassed a set of TEs that had previously been shown to decrease expression within a 24 nt siRNA biogenesis mutant (mop1). To investigate the evolutionary dynamics of the three groups, we estimated their abundance in two landraces, one with a genome similar in size to that of the maize reference and the other with a 30% larger genome. For all three accessions, we assessed TE abundance as well as 22 nt and 24 nt siRNA content within leaves. The high copy number retroelements are under targeted similarly by siRNAs among accessions, appear to be born of a rapid bust of activity, and may be currently transpositionally dead or limited. In contrast, the lower copy number group of retrolements are targeted more dynamically and have had a long and ongoing history of transposition in the maize genome. PMID:24743518

Diez, Concepcion M.; Meca, Esteban; Tenaillon, Maud I.; Gaut, Brandon S.



Characterizing the Heavy Elements in Globular Cluster M22 and an Empirical s-process Abundance Distribution Derived from the Two Stellar Groups  

E-print Network

We present an empirical s-process abundance distribution derived with explicit knowledge of the r-process component in the low-metallicity globular cluster M22. We have obtained high-resolution, high signal-to-noise spectra for 6 red giants in M22 using the MIKE spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory. In each star we derive abundances for 44 species of 40 elements, including 24 elements heavier than zinc (Z=30) produced by neutron-capture reactions. Previous studies determined that 3 of these stars (the "r+s group") have an enhancement of s-process material relative to the other 3 stars (the "r-only group"). We confirm that the r+s group is moderately enriched in Pb relative to the r-only group. Both groups of stars were born with the same amount of r-process material, but s-process material was also present in the gas from which the r+s group formed. The s-process abundances are inconsistent with predictions for AGB stars with M =< 3 Msun and suggest an origin in more mass...

Roederer, I U; Sneden, C



Discovery of probable Tunguska cosmic body material: anomalies of platinum group elements and rare-earth elements in peat near the Explosion Site /(1908)  

NASA Astrophysics Data System (ADS)

Ten Sphagnum fuscum peat samples collected from different depths of a core including the layer affected by the 1908 Tunguska explosion in the Tunguska area of Central Siberia, Russia, were analyzed by ICP-MS to determine the concentrations of Pd, Rh, Ru, Co, REE, Y, Sr, and Sc. The analytical results indicate that the Pd and Rh concentrations in the event- and lower layers were 14.0-19.9, and 1.23-1.56 ppb, respectively, about 3-9 times and 3 times higher than the background values in the normal layers. In addition, the patterns of CI-chondrite-normalized REE in the event layers were much flatter than in the normal layers, and differed from those in the nearby traps. Hence, it can be inferred from the characteristics of the elemental geochemistry that the explosion was probably associated with extraterrestrial material, and which, most probably, was a small comet core the dust fraction of which was chemically similar to carbonaceous chondrites (CI). In terms of the Pd and REE excess fluxes in the explosion area, it can be estimated that the celestial body that exploded over Tunguska in 1908 weighed more than 10 6 t, corresponding to a radius of >60 m. If the celestial body was a comet, then its total mass was more than 2×10 7 t, and it had >160 m radius, and released an energy of >10 7 t TNT.

Hou, Q. L.; Kolesnikov, E. M.; Xie, L. W.; Zhou, M. F.; Sun, M.; Kolesnikova, N. V.



Rhenium-osmium isotope and platinum-group elements in the Xinjie layered intrusion, SW China: Implications for source mantle composition, mantle evolution, PGE fractionation and mineralization  

NASA Astrophysics Data System (ADS)

The Xinjie mafic-ultramafic layered intrusion in the Emeishan large igneous province (ELIP) hosts Cu-Ni-platinum group element (PGE) sulfide ore layers within the lower part and Fe-Ti-V oxide-bearing horizons within the middle part. The major magmatic Cu-Ni-PGE sulfide ores and spatially associated cumulate rocks are examined for their PGE contents and Re-Os isotopic systematics. The samples yielded a Re-Os isochron with an age of 262 ± 27 Ma and an initial 187Os/ 188Os of 0.12460 ± 0.00011 ( ?Os( t) = -0.5 ± 0.1). The age is in good agreement with the previously reported U-Pb zircon age, indicating that the Re-Os system remained closed for most samples since the intrusion emplacement. They have near-chondritic ?Os( t) values ranging from -0.7 to -0.2, similar to those of the Lijiang picrites and Song Da komatiites. Exceptionally, two samples from the roof zone and one from upper sequence exhibit radiogenic ?Os( t) values (+0.6 to +8.6), showing minor contamination by the overlying Emeishan basalts. The PGE-rich ores contain relatively high PGE and small amounts of sulfides (generally less than 2%) and the abundance of Cu and PGE correlate well with S, implying that the distribution of these elements is controlled by the segregation and accumulation of a sulfide liquid. Some ore samples are poor in S (mostly <800 ppm), which may due to late-stage S loss caused by the dissolution of FeS from pre-existing sulfides through their interaction with sulfide-unsaturated flowing magma. The combined study shows that the Xinjie intrusion may be derived from ferropicritic magmas. The sharp reversals in Mg#, Cr/FeO T and Cr/TiO 2 ratios immediately below Units 2-4, together with high Cu/Zr ratios decreasing from each PGE ore layer within these cyclic units, are consistent with multiple magma replenishment episodes. The sulfides in the cumulate rocks show little evidence of PGE depletion with height and thus appear to have segregated from successive inputs of fertile magma. This suggests that the Xinjie intrusion crystallized from in an open magma system, e.g., a magma conduit. The compositions of the disseminated sulfides in most samples can be modeled by applying an R factor (silicate-sulfide mass ratio) of between 1000 and 8000, indicating the segregation of only small amounts of sulfide liquid in the parental ferropicritic magmas. Thus, continuous mixing between primitive ferropicritic magma and differentiated resident magma could lead to crystallization of chromite, Cr-bearing magnetite and subsequently abundant Fe-Ti oxides, thereby the segregation of PGE-rich Cu-sulfide. When considered in the light of previous studies on plume-derived komatiites and picrites worldwide, the close-to-chondritic Os isotopic composition for most Xinjie samples, Lijiang picrites and Song Da komatiites suggest that the ferropicritic magma in the ELIP were generated from a plume. This comprised recycled Neoproterozic oceanic lithosphere, including depleted peridotite mantle embedded with geochemically enriched domains. The ascending magmas thereafter interacted with minor (possibly <10%) subducted/altered oceanic crust. This comparison suggests that the komatiitic melts in the ELIP originated from a greater-than normal degree of melting of incompatible trace element depleted, refractory mantle components in the plume source.

Zhong, Hong; Qi, Liang; Hu, Rui-Zhong; Zhou, Mei-Fu; Gou, Ti-Zhong; Zhu, Wei-Guang; Liu, Bing-Guang; Chu, Zhu-Yin



Genetic diversity of European phytoplasmas of the 16SrV taxonomic group and proposal of 'Candidatus Phytoplasma rubi'.  


In addition to the grapevine flavescence dorée phytoplasmas, other members of taxonomic group 16SrV phytoplasmas infect grapevines, alders and species of the genera Clematis and Rubus in Europe. In order to investigate which phytoplasmas constitute discrete, species-level taxa, several strains were analysed by comparing their 16S rRNA gene sequences and a set of five housekeeping genes. Whereas 16S rRNA gene sequence similarity values were >97.5?%, the proposed threshold to distinguish two 'Candidatus Phytoplasma' taxa, phylogenetic analysis of the combined sequences of the tuf, rplV-rpsC, rplF-rplR, map and uvrB-degV genetic loci showed that two discrete phylogenetic clusters could be clearly distinguished. The first cluster grouped flavescence dorée (FD) phytoplasmas, alder yellows (AldY) phytoplasmas, Clematis (CL) phytoplasmas and the Palatinate grapevine yellows (PGY) phytoplasmas. The second cluster comprised Rubus stunt (RS) phytoplasmas. In addition to the specificity of the insect vector, the Rubus stunt phytoplasma contained specific sequences in the 16S rRNA gene. Hence, the Rubus stunt phytoplasma 16S rRNA gene was sufficiently differentiated to represent a novel putative taxon: 'Candidatus Phytoplasma rubi'. PMID:20889771

Malembic-Maher, Sylvie; Salar, Pascal; Filippin, Luisa; Carle, Patricia; Angelini, Elisa; Foissac, Xavier



Behavior of iron-group elements, oxybarometry, and genesis of unique chromite deposits in the Kempirsai massif  

NASA Astrophysics Data System (ADS)

Ultramafic rocks and high-Cr chromite ore from the Almaz-Zhemchuzhina deposit, the largest in the Main ore field of the Kempirsai massif, have been studied. The detailed mineralogical and geochemical examination of deep structure test and exploratory boreholes allowed us to establish the rough stratification of ultramafic rocks and to demonstrate the position of unique chromite deposits in the generalized vertical section of the southeastern Kempirsai massif. From top to bottom, a barren harzburgite-lherzolite series gives way to an ore-bearing dunite-harzburgite complex with the largest chromite deposits, including the unique Almaz-Zhemchuzhina deposit, in its upper portion and then to pyroxene-free dunite densely impregnated with chromite in the upper part and containing sparsely disseminated chromite at its base. The lower unit is composed of a barren lherzolite-harzburgite series transformed into blastomylonites near the contact with dunite, suggesting a tectonically doubled section in the southeastern part of the massif. The synore asymmetric geochemical zoning developed in the course of formation of chromite deposits as a result of removal of oreforming iron-group elements from the underlying and wall ultramafic rocks into the overlying rocks. Host rocks with disturbed initial proportions of Cr, Fe, Ni, and Mn, together with orebodies, made up ore-bearing zones no less than 1 km in thickness and subdivided into supra-, inter-, and subore subzones. The subore and wall rocks are characterized by partial loss (wt %) of Cr2O3(0.1), NiO (0.04), FeOtot(0.5), and MnO (0.02) and their removal into the interore and supraore (0.03 NiO) subzones. Thus, the subore ultramafic rocks served as a source of ore-forming components, while the interore zone with orebodies occurring therein served as a zone of discharge of these components. Using Mössbauer spectroscopy, the crystal chemistry of iron ions was studied in a representative selection of Cr-spinel samples from rocks and ores of the southeastern and western blocks (the Almaz-Zhemchuzhina and Geophysical XII deposits). The degree of iron oxidation in the samples varies from 8 to 33%. In most cases, a difference in degree of iron oxidation is established in stoichiometric approximation and from Mössbauer data. In other words, the integral stoichiometry of ferrous and ferric ions is disturbed. Such a disturbance may be related not only to partial inversion of the Cr-spinel structure but also to local heterogeneity of the mineral at the micro- and nanolevels with clustering of cations and formation of their associates. An empirical correction of the olivine-Cr-spinel geothermometer and oxybarometer has been performed. The inverse correlation between oxygen fugacity and degree of depletion of ultramafic rocks indicates that these rocks were formed in a closed system with participation of a water-methane fluid. Along with stratification of ultramafics, this correlation testifies to a powerful asthenospheric source of reduced fluids. The retention of low oxygen fugacity in central portions of orebodies does not rule out that after a break this source participated in the formation of unique chromite deposits in the Kempirsai massif.

Chashchukhin, I. S.; Votyakov, S. L.



Dia, Jsa and V Blood Groups in South and South-East Asia  

Microsoft Academic Search

THE red-cell antigens, Dia and Jsa, are among those of special interest as genetic markers in human populations because they attain reasonable frequency in at least one of the major divisions of the human race, but are rare or entirely absent in all others. The Dia blood-group factor is restricted to American Indians and Mongoloid populations1 or those of mixed

G. H. Vos




Microsoft Academic Search

Let R be a commutative ring, V a nitely generated free R-module and G GLR(V ) a nite group acting naturally on the graded symmetric algebra A = S(V ). Let (V;G) denote the minimal number m, such that the ring AG of invariants can be generated by nitely many elements of degree at most m. For G = n



Platinum-group elements in southern Africa: mineral inventory and an assessment of undiscovered mineral resources: Chapter Q in Global Mineral Resource Assessment  

USGS Publications Warehouse

The platinum-group elements, platinum, palladium, rhodium, ruthenium, iridium, and osmium, possess unique physical and chemical characteristics that make them indispensable to modern technology and industry. However, mineral deposits that are the main sources of these elements occur only in three countries in the world, raising concerns about potential disruption in mineral supply. Using information in the public domain, mineral resource and reserve information has been compiled for mafic and ultramafic rocks in South Africa and Zimbabwe that host most of the world’s platinum-group element resources. As of 2012, exploration and mining companies have delineated more than 20 billion metric tons of mineralized rock containing 42,000 metric tons of platinum, 29,000 metric tons of palladium, and 5,200 metric tons of rhodium, primarily in mafic and ultramafic intrusions of the Bushveld Complex and the Great Dyke, in southern Africa. Additional mineralized rock is likely to occur in extensions to the well-explored and characterized volumes of mineralized rock. Underexplored extensions of stratabound platinum-group element (PGE) deposits in the Bushveld Complex in South Africa may contain 65,000 metric tons of platinum, palladium, and rhodium to a depth of 3 km. Rocks enriched in PGE, which occur near the contact of the Bushveld Complex with older Transvaal Supergroup sedimentary rocks, may contain 1,100 metric tons of platinum and 1,370 metric tons of palladium (mean estimate to a depth of 1 km). A stratabound platinum-group element deposit in the Great Dyke in Zimbabwe may contain 6,900 metric tons of undiscovered platinum, palladium, and rhodium. By comparison, the global net demand for PGE in 2012 was approximately 460 metric tons. Since the 1920s, mining has recovered 7,200 and 107 metric tons of platinum-group elements from the Bushveld Complex and the Great Dyke, respectively. The large layered intrusions in southern Africa—the Bushveld Complex and the Great Dyke—are now and will continue to be a major source of the world’s supply of PGE. Mining will not deplete the identified mineral resources and reserves or potential undiscovered mineral resources for many decades; however, in the near-term, PGE supply could be affected by social, environmental, political, and economic factors.

Zientek, Michael L.; Causey, J. Douglas; Parks, Heather L.; Miller, Robert J.



Finite element simulation of high-speed machining of titanium alloy (Ti–6Al–4V) based on ductile failure model  

Microsoft Academic Search

A Johnson–Cook material model with an energy-based ductile failure criterion is developed in titanium alloy (Ti–6Al–4V) high-speed\\u000a machining finite element analysis (FEA). Furthermore, a simulation procedure is proposed to simulate different high-speed\\u000a cutting processes with the same failure parameter (i.e., density of failure energy). With this finite element (FE) model,\\u000a a series of FEAs for titanium alloy in extremely high-speed

Guang Chen; Chengzu Ren; Xiaoyong Yang; Xinmin Jin; Tao Guo


The use of mantle normalization and metal ratios in the identification of the sources of platinum-group elements in various metal-rich black shales  

Microsoft Academic Search

It has been shown that Ni\\/Cu versus Pd\\/Ir and Cu\\/Ir versus Ni\\/Pd ratios, as well as mantle-normalized metal patterns can be successfully used to evaluate the effects of partial melting, crystal fractionation and sulfide saturation in mafic and ultramafic rocks. Platinum-group element (PGE) enrichments occur in Zn-, Cu- and Ni-rich black shales in a number of geological settings. These facies

Jan Pasava; Sarah-Jane Barnes; Anna Vymazalová



Report of the IAU/IAG/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites - 1991  

NASA Technical Reports Server (NTRS)

Revised values are presented for the directions of the north poles of rotation, the prime meridians, and for the sizes and shapes of the planets and satellites. Also presented are definitions of rotational elements and the cartographic coordinate systems. These revised values and definitions are the results of a report provided every three years by an international working group with members from IAU, IAG, and COSPAR.

Davies, M. E.; Abalakin, V. K.; Brahic, A.; Bursa, M.; Chovitz, B. H.; Lieske, J. H.; Seidelmann, P. K.; Sinclair, A. T.; Tiuflin, I. S.



Quantifying the platinum group elements (PGEs) and gold in geological samples using cation exchange pretreatment and ultrasonic nebulization inductively coupled plasma-mass spectrometry (USN-ICP-MS)  

Microsoft Academic Search

A method for analyzing low abundances of the platinum group elements (PGEs) and gold has been developed using cation exchange chromatography and ultrasonic nebulization inductively coupled plasma mass spectrometry (USN-ICP-MS). Ultrasonic nebulization increases sensitivity over regular pneumatic nebulization so that resolvable signals above background are possible in the fg\\/g range. Small sample sizes (?250 mg) and low volumes of reagents

James C. Ely; Clive R. Neal; James A. O'Neill; Jinesh C. Jain



Spin-orbit effects, VSEPR theory, and the electronic structures of heavy and superheavy group IVA hydrides and group VIIIA tetrafluorides. A partial role reversal for elements 114 and 118  

SciTech Connect

Relativistic effective core potentials and spin-orbit operators are used in relativistic configuration interaction calculations to explore the effects of spin-orbit coupling on the electronic structures of atoms and molecules of elements 114 and 118. The monohydrides of group IVA and the tetrafluorides of group VIIIA are examined in order to provide examples of trends within families among the various periods. The spin-orbit effect is found to play a dominant role in the determination of atomic and molecular properties. Several nonintuitive consequences of spin-orbit coupling are presented, including the depiction of element 114 as a closed-shell noble atom and the suggestion that the VSEPR theory in inadequate to describe the geometry of the rare gas tetrafluoride, (118)F{sub 4}.

Nash, C.S. [Lawrence Livermore National Lab., CA (United States). Glenn T. Seaborg Inst. for Transactinium Science] [Lawrence Livermore National Lab., CA (United States). Glenn T. Seaborg Inst. for Transactinium Science; Bursten, B.E. [Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry] [Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry



Direct observation of N-(group V) bonding defects in dilute nitride semiconductors using hard x-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Using bulk sensitive hard x-ray photoelectron spectroscopy, we directly observe a spectrum related to N-As bonding defects in (Ga,In)(N,As)/Ga(N,As) heterostructure. The defects are most likely attributed to split interstitials. Their concentration is in the order of 1019 cm-3, close to the detection limit of the measurement. Rapid thermal annealing eliminates the defects, leading to those undetectable. Similar phenomenon is observed for N-P bonding defects in In(N,P). The results indicate common features in dilute nitride semiconductor system: existence of N-(group V) bonding defects and their behavior on postgrowth annealing.

Ishikawa, F.; Fuyuno, S.; Higashi, K.; Kondow, M.; Machida, M.; Oji, H.; Son, J.-Y.; Trampert, A.; Umeno, K.; Furukawa, Y.; Wakahara, A.



A preliminary report on x-ray photoabsorption coefficients and atomic scattering factors for 92 elements in the 10--10,000 eV region  

Microsoft Academic Search

Based on currently available photoabsorption measurements and recent theoretical calculations by Doolen and Liberman, a revised best-fit determination of the photoabsorption cross sections is presented here for the elements Z = 1 to Z = 92 in the 10--10,000 eV range. The photoabsorption data used include those described in the Lockheed and DOE listings of research abstracts for the past

B. L. Henke; J. C. Davis; E. M. Gullikson; R. C. C. Perera



Top quark mass measurement in the t tmacr all hadronic channel using a matrix element technique in p pmacr collisions at s=1.96TeV  

Microsoft Academic Search

We present a measurement of the top quark mass in the all hadronic channel (t tmacr -->b bmacr q1 qmacr 2q3 qmacr 4) using 943pb-1 of p pmacr collisions at s=1.96TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix element (ME) to t tmacr candidate events. We calculate per-event probability

T. Aaltonen; J. Adelman; T. Akimoto; B. Álvarez González; S. Amerio; D. Amidei; A. Anastassov; A. Annovi; J. Antos; G. Apollinari; A. Apresyan; T. Arisawa; A. Artikov; W. Ashmanskas; A. Attal; A. Aurisano; F. Azfar; P. Azzurri; W. Badgett; A. Barbaro-Galtieri; V. E. Barnes; B. A. Barnett; V. Bartsch; G. Bauer; P.-H. Beauchemin; F. Bedeschi; D. Beecher; S. Behari; G. Bellettini; J. Bellinger; D. Benjamin; A. Beretvas; J. Beringer; A. Bhatti; M. Binkley; D. Bisello; I. Bizjak; R. E. Blair; C. Blocker; B. Blumenfeld; A. Bocci; A. Bodek; V. Boisvert; G. Bolla; D. Bortoletto; J. Boudreau; A. Boveia; B. Brau; A. Bridgeman; L. Brigliadori; C. Bromberg; E. Brubaker; J. Budagov; H. S. Budd; S. Budd; S. Burke; K. Burkett; G. Busetto; P. Bussey; A. Buzatu; K. L. Byrum; S. Cabrera; C. Calancha; M. Campanelli; M. Campbell; F. Canelli; A. Canepa; B. Carls; D. Carlsmith; R. Carosi; S. Carrillo; S. Carron; B. Casal; M. Casarsa; A. Castro; P. Catastini; D. Cauz; V. Cavaliere; M. Cavalli-Sforza; A. Cerri; L. Cerrito; S. H. Chang; Y. C. Chen; M. Chertok; G. Chiarelli; G. Chlachidze; F. Chlebana; K. Cho; D. Chokheli; J. P. Chou; G. Choudalakis; S. H. Chuang; K. Chung; W. H. Chung; Y. S. Chung; T. Chwalek; C. I. Ciobanu; M. A. Ciocci; A. Clark; D. Clark; G. Compostella; M. E. Convery; J. Conway; M. Cordelli; G. Cortiana; C. A. Cox; D. J. Cox; F. Crescioli; C. Cuenca Almenar; J. Cuevas; R. Culbertson; J. C. Cully; D. Dagenhart; M. Datta; T. Davies; P. de Barbaro; S. de Cecco; A. Deisher; G. de Lorenzo; M. Dell'Orso; C. Deluca; L. Demortier; J. Deng; M. Deninno; P. F. Derwent; G. P. di Giovanni; C. Dionisi; B. di Ruzza; J. R. Dittmann; M. D'Onofrio; S. Donati; P. Dong; J. Donini; T. Dorigo; S. Dube; J. Efron; A. Elagin; R. Erbacher; D. Errede; S. Errede; R. Eusebi; H. C. Fang; S. Farrington; W. T. Fedorko; R. G. Feild; M. Feindt; J. P. Fernandez; C. Ferrazza; R. Field; G. Flanagan; R. Forrest; M. J. Frank; M. Franklin; J. C. Freeman; I. Furic; M. Gallinaro; J. Galyardt; F. Garberson; J. E. Garcia; A. F. Garfinkel; K. Genser; H. Gerberich; D. Gerdes; A. Gessler; S. Giagu; V. Giakoumopoulou; P. Giannetti; K. Gibson; J. L. Gimmell; C. M. Ginsburg; N. Giokaris; M. Giordani; P. Giromini; M. Giunta; G. Giurgiu; V. Glagolev; D. Glenzinski; M. Gold; N. Goldschmidt; A. Golossanov; G. Gomez; G. Gomez-Ceballos; M. Goncharov; O. González; I. Gorelov; A. T. Goshaw; K. Goulianos; A. Gresele; S. Grinstein; C. Grosso-Pilcher; U. Grundler; J. Guimaraes da Costa; Z. Gunay-Unalan; C. Haber; K. Hahn; S. R. Hahn; E. Halkiadakis; B.-Y. Han; J. Y. Han; F. Happacher; K. Hara; D. Hare; M. Hare; S. Harper; R. F. Harr; R. M. Harris; M. Hartz; K. Hatakeyama; C. Hays; M. Heck; A. Heijboer; J. Heinrich; C. Henderson; M. Herndon; J. Heuser; S. Hewamanage; D. Hidas; C. S. Hill; D. Hirschbuehl; A. Hocker; S. Hou; M. Houlden; S.-C. Hsu; B. T. Huffman; R. E. Hughes; U. Husemann; M. Hussein; J. Huston; J. Incandela; G. Introzzi; M. Iori; A. Ivanov; E. James; B. Jayatilaka; E. J. Jeon; M. K. Jha; S. Jindariani; W. Johnson; M. Jones; K. K. Joo; S. Y. Jun; J. E. Jung; T. R. Junk; T. Kamon; D. Kar; P. E. Karchin; Y. Kato; R. Kephart; J. Keung; V. Khotilovich; B. Kilminster; D. H. Kim; H. S. Kim; H. W. Kim; J. E. Kim; M. J. Kim; S. B. Kim; S. H. Kim; Y. K. Kim; N. Kimura; L. Kirsch; S. Klimenko; B. Knuteson; B. R. Ko; K. Kondo; D. J. Kong; J. Konigsberg; A. Korytov; A. V. Kotwal; M. Kreps; J. Kroll; D. Krop; N. Krumnack; M. Kruse; V. Krutelyov; T. Kubo; T. Kuhr; N. P. Kulkarni; M. Kurata; S. Kwang; A. T. Laasanen; S. Lami; S. Lammel; M. Lancaster; R. L. Lander; K. Lannon; A. Lath; G. Latino; I. Lazzizzera; T. Lecompte; E. Lee; H. S. Lee; S. W. Lee; S. Leone; J. D. Lewis; C.-S. Lin; J. Linacre; M. Lindgren; E. Lipeles; A. Lister; D. O. Litvintsev; C. Liu; T. Liu; N. S. Lockyer; A. Loginov; M. Loreti; L. Lovas; D. Lucchesi; C. Luci; J. Lueck; P. Lujan; P. Lukens; G. Lungu; L. Lyons; J. Lys; R. Lysak; D. MacQueen; R. Madrak; K. Maeshima; K. Makhoul; T. Maki; P. Maksimovic; S. Malde; S. Malik; G. Manca; A. Manousakis-Katsikakis; F. Margaroli; C. Marino; A. Martin; V. Martin; M. Martínez; R. Martínez-Ballarín; T. Maruyama; P. Mastrandrea; T. Masubuchi; M. Mathis; M. E. Mattson; P. Mazzanti; K. S. McFarland; P. McIntyre; R. McNulty; A. Mehta; P. Mehtala; A. Menzione; P. Merkel; C. Mesropian; T. Miao; N. Miladinovic; R. Miller; C. Mills; M. Milnik; A. Mitra; G. Mitselmakher; H. Miyake; N. Moggi; C. S. Moon; R. Moore; M. J. Morello; J. Morlok; P. Movilla Fernandez; J. Mülmenstädt; A. Mukherjee; Th. Muller; R. Mumford; P. Murat; M. Mussini; J. Nachtman; Y. Nagai; A. Nagano; J. Naganoma; K. Nakamura; I. Nakano; A. Napier; V. Necula; J. Nett; C. Neu; M. S. Neubauer; S. Neubauer; J. Nielsen; L. Nodulman; M. Norman; O. Norniella; E. Nurse; L. Oakes; S. H. Oh; Y. D. Oh; I. Oksuzian; T. Okusawa; R. Orava; S. Pagan Griso; E. Palencia; V. Papadimitriou



A measurement of the top quark mass in 1.96 TeV proton-antiproton collisions using a novel matrix element method  

SciTech Connect

A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix elements techniques, the method involves an integration using the Standard Model matrix element for tt production and decay. however, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb{sup -1} data sample, using events with a high-p{sub T} lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find M{sub meas} = 169.8 {+-} 2.3(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.

Freeman, John C.; /LBL, Berkeley



A Measurement of the Top Quark Mass in 1.96 TeV Proton-Antiproton Collisions Using a Novel Matrix Element Method  

SciTech Connect

A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix element techniques, the method involves an integration using the Standard Model matrix element for t{bar t} production and decay. However, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb{sup -1} data sample, using events with a high-p{sub T} lepton and exactly four high-energy jets, at least one of which is tagged as coming from a b quark; 149 events pass all the selection requirements. They find M{sub meas} = 169.8 {+-} 2.3(stat.) {+-} 1.4(syst.) GeV/c{sup 2}.

CDF Collaboration; Freeman, John; Freeman, John



A double stellar generation in the globular cluster NGC 6656 (M 22). Two stellar groups with different iron and s-process element abundances  

NASA Astrophysics Data System (ADS)

We present a chemical abundance analysis based on high resolution UVES spectra of seventeen bright giant stars in the Globular Cluster (GC) M 22. We obtained an average iron abundance of [Fe/H] = -1.76±0.02 (internal errors only) and an ? enhancement of 0.36±0.04 (internal errors only). Na and O, and Al and O follow the well known anticorrelations found in many other GCs. We identified two groups of stars with significantly different abundances of the s-process elements Y, Zr, and Ba. The relative numbers of the two group members are very similar to the ratio of the number of stars in the two sub giant branches (SGB) of M 22. Y and Ba abundances do not correlate with Na, O, and Al. The s-element rich stars are also richer in iron and have higher Ca abundances. The results from high resolution spectra were confirmed by analyses of lower resolution GIRAFFE spectra of fourteen additional M 22 stars. The analyses of the GIRAFFE spectra also show that the Eu - a pure r-process element - abundance is not related to the iron content. We discuss the chemical abundance pattern of M 22 stars in the context of GC multiple stellar populations phenomenon. Based on data collected at the European Southern Observatory with the VLT-UT2, Paranal, Chile.

Marino, A. F.; Milone, A. P.; Piotto, G.; Villanova, S.; Bedin, L. R.; Bellini, A.; Renzini, A.



Barclays Bank PLC v. Franchise Tax Board of California: Does the Application of Worldwide Unitary Taxation to Non-U.S. Parent Corporate Groups Violate the Commerce Clause?  

Microsoft Academic Search

This Comment examines whether the Supreme Court in Barclays v. Franchise Tax Board, correctly decided that the application of worldwide unitary taxation to non-U.S. parent groups does not violate the Commerce Clause.

Zain E. Husain



75 FR 45623 - Morris Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil LLC; and PSEG Power LLC...  

Federal Register 2010, 2011, 2012, 2013

...Energy Group, LLC v.PSEG Energy Resources & Trade LLC; PSEG Fossil LLC; and PSEG Power LLC; Notice of Complaint July 27, 2010...complaint against PSEG Energy Resources & Trade, LLC, PSEG Fossil LLC and PSEG Power LLC (PSEG Power Companies)...



Synthesis, structures and bonding of superconducting barium vanadium sulfide and intermetallic solid state compounds of group 2, 3, 13, 14 and transition elements  

Microsoft Academic Search

Superconducting transition is well known for the Chevrel phases M xMo6S8 and MxMo6Se 8 where M is dopant metal such as Pb, In, Tl and La. Not many ternary group 5 transition metal chalcogenides of similar composition, however, are known to be superconductors. The synthesis and observation of superconducting transition of the Ba doped compound BaxV6S8 (x = 0.45--0.48) is

Kim Carl Lobring



Spin Density Matrix Elements in Exclusive rho^0 Electroproduction on 1H and 2H Targets at 27.5 GeV Beam Energy  

E-print Network

Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive rho^0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1 GeV^2 < Q^2 < 7 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t < 0.4 GeV^2. Within the given experimental uncertainties, a hierarchy of relative sizes of helicity amplitudes is observed. Kinematic dependences of all SDMEs on Q^2 and t are presented, as well as the longitudinal-to-transverse rho^0 electroproduction cross section ratio as a function of Q^2. A small but statistically significant deviation from the hypothesis of s-channel helicity conservation is observed. An indication is seen of a contribution of unnatural-parity-exchange amplitudes; these amplitudes are naturally generated with a quark-exchange mechanism.

HERMES Collaboration; A. Airapetian



Modulation of the Activity of a Polycomb-Group Response Element in Drosophila by a Mutation in the Transcriptional Activator Woc  

PubMed Central

Polycomb group response elements (PRE) are cis-regulatory elements that bind Polycomb group proteins. We are studying a 181-bp PRE from the Drosophila engrailed gene. This PRE causes pairing-sensitive silencing of mini-white in transgenes. Here we show that the 181-bp PRE also represses mini-white expression in flies with only one copy of the transgene. To isolate mutations that alter the activity of the 181-bp PRE, we screened for dominant suppressors of PRE-mediated mini-white repression. Dominant suppressors of mini-white repression were rare; we recovered only nine mutations out of 68,274 progeny screened. Two of the nine mutations isolated are due to the same single amino acid change in the transcriptional activator Woc (without children). Reversion experiments show that these are dominant gain-of-function mutations in woc. We suggest that Woc can interfere with the activity of the PRE. Our data have implications for how Polycomb group proteins act to either partially repress or completely silence their target genes. PMID:22384357

Noyes, Amanda; Stefaniuk, Catherine; Cheng, Yuzhong; Kennison, James A.; Kassis, Judith A.



Exploring the potential energy surface of E?P? clusters (E=Group 13 element): the quest for inverse carbon-free sandwiches.  


Inverse carbon-free sandwich structures with formula E2P4 (E=Al, Ga, In, Tl) have been proposed as a promising new target in main-group chemistry. Our computational exploration of their corresponding potential-energy surfaces at the S12h/TZ2P level shows that indeed stable carbon-free inverse-sandwiches can be obtained if one chooses an appropriate Group?13 element for E. The boron analogue B2P4 does not form the D(4h)-symmetric inverse-sandwich structure, but instead prefers a D(2d) structure of two perpendicular BP2 units with the formation of a double B-B bond. For the other elements of Group?13, Al-Tl, the most favorable isomer is the D(4h) inverse-sandwich structure. The preference for the D(2d) isomer for B2P4 and D(4h) for their heavier analogues has been rationalized in terms of an isomerization-energy decomposition analysis, and further corroborated by determination of aromaticity of these species. PMID:24700524

Castro, Abril C; Osorio, Edison; Cabellos, José Luis; Cerpa, Erick; Matito, Eduard; Solà, Miquel; Swart, Marcel; Merino, Gabriel



Modeling of the bremsstrahlung radiation produced in pure-element targets by 10-40 keV electrons  

Microsoft Academic Search

A new global relationship has been developed for predicting electron-excited bremsstrahlung intensities over a wide range of accelerating voltages 10--40 keV, atomic numbers 4--92, and x-ray energies 1.5--20 keV. The new relationship was determined empirically from the mathematical modeling of extensive data and is designed for calculating bremsstrahlung intensities in analytical procedures, such as those requiring peak-to-background measurements, where the

John A. Small; Stefan D. Leigh; Dale E. Newbury; Robert L. Myklebust



Modeling of the bremsstrahlung radiation produced in pure-element targets by 10–40 keV electrons  

Microsoft Academic Search

A new global relationship has been developed for predicting electron-excited bremsstrahlung intensities over a wide range of accelerating voltages 10–40 keV, atomic numbers 4–92, and x-ray energies 1.5–20 keV. The new relationship was determined empirically from the mathematical modeling of extensive data and is designed for calculating bremsstrahlung intensities in analytical procedures, such as those requiring peak-to-background measurements, where the

John A. Small; Stefan D. Leigh; Dale E. Newbury; Robert L. Myklebust




Microsoft Academic Search

Because of their desirable properties, such as high strength to weight ratio and corrosion resistance, titanium alloys are commonly employed in the aerospace and medical device industries. Titanium alloys are known to be difficult to machine, so the selection of cutting conditions with minimal experimental effort is important for manufacturers. Finite element modeling, which is an indispensable tool to understand

Y. Karpat




NSDL National Science Digital Library

This is an online interactive periodic table of the elements which includes all elements up to 118. There are several different options for viewing, such as date of discovery, electron configuration, number of neutrons, etc. Elements can also be viewed by element groups. Additional links to further information on a particluar element are given in some cases. Citation information is also provided.

Bentor, Yinon



A novel structure of Tn4001-truncated element, type V, in clinical enterococcal isolates and multiplex PCR for detecting aminoglycoside resistance genes.  


A multiplex polymerase chain reaction (PCR) was established for detecting aacA-aphD, aph(2'')-Ib, aph(2'')-Ic and aph(2'')-Id, encoding high-level gentamicin resistance (HLGR), and aadA and aadE, encoding high-level streptomycin resistance (HLSR), in enterococci. The assay was implemented for 419 enterococcal blood and urine isolates recovered from patients at a university hospital in Thailand. Among the isolates tested, 56.1% (235 isolates) and 58.9% (247 isolates) contained aacA-aphD and aadE, respectively. The aph(2'')-Ib, aph(2'')-Ic, aph(2'')-Id and aadA genes were not found in any isolate. Among the isolates carrying the aacA-aphD gene, 99.1% exhibited a HLGR phenotype. All 235 enterococcal isolates containing aacA-aphD were further studied by PCR to characterise the structure of the resistance determinants carrying the aacA-aphD gene. The result revealed that only 22.6% carried Tn4001-related element, whereas the remaining isolates contained Tn4001-truncated element. No Tn4001-IS257 hybrid structure was detected. The majority of isolates carrying Tn4001-related element were Enterococcus faecalis (77.4%). Among Tn4001-truncated elements detected, all previously reported types (types I-IV) were found. Furthermore, a novel Tn4001-truncated type, designated type V, was also identified. PMID:18155882

Leelaporn, A; Yodkamol, K; Waywa, D; Pattanachaiwit, S



The origin and distribution of HAPs elements in relation to maceral composition of the A1 lignite bed (Paleocene, Calvert Bluff Formation, Wilcox Group), Calvert mine area, east-central Texas  

USGS Publications Warehouse

The origin and distribution of twelve potentially Hazardous Air Pollutants (HAPs; As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb Sb, Se, and U) identified in the 1990 Clean Air Act Amendments were examined in relation to the maceral composition of the A1 bed (Paleocene, Calvert Bluff Formation, Wilcox Group) of the Calvert mine in east-central Texas. The 3.2 m-thick A1 bed was divided into nine incremental channel samples (7 lignite samples and 2 shaley coal samples) on the basis of megascopic characteristics. Results indicate that As, Cd, Cr, Ni, Pb, Sb, and U are strongly correlated with ash yield and are enriched in the shaley coal samples. We infer that these elements are associated with inorganic constituents in the coal bed and may be derived from a penecontemporaneous stream channel located several kilometers southeast of the mining block. Of the HAPs elements studied, Mn and Hg are the most poorly correlated to ash yield. We infer an organic association for Mn; Hg may be associated with pyrite. The rest of the trace elements (Be, Co, and Se) are weakly correlated with ash yield. Further analytical work is necessary to determine the mode of occurrence for these elements. Overall, concentrations of the HAPs elements are generally similar to or less than those reported in previous studies of lignites of the Wilcox Group, east-central region, Texas. Petrographic analysis indicates the following ranges in composition for the seven lignite samples: liptinites (5-8%), huminites (88-95%), and inertinites (trace amounts to 7%). Samples from the middle portion of the A1 bed contain abundant crypto-eugelinite compared to the rest of the samples; this relationship suggests that the degradation of plant material was an important process during the development of the peat mire. With the exception of Hg and Mn, relatively low levels of the HAPs elements studied are found in the samples containing abundant crypto-eugelinite. We infer that the peat-forming environment for this portion of the coal bed was very wet with minimal detrital input. Relatively high concentrations of crypto-humotelinite were found in samples from the top and base of the coal bed. The presence of abundant crypto-humotelinite in this part of the coal bed suggests the accumulation of wood-rich peat under conditions conducive to a high degree of tissue preservation in the peat mire. Although several of the trace elements (Be, Co, Ni, and Sb) exhibit enrichment in these samples, they are not necessarily chemically associated with humotelinite. We infer that these elements, with the exception of Be, are possibly associated with deposition of the roof and floor rock of the coal bed; however, further analytical work would be necessary to confirm this hypothesis. Beryllium may have an organic origin. ?? 1997 Elsevier Science B.V.

Crowley, S.S.; Warwick, P.D.; Ruppert, L.F.; Pontolillo, J.



Formation and geochemical significance of micrometallic aggregates including fissiogenic platinum group elements in the Oklo natural reactor, Gabon  

NASA Astrophysics Data System (ADS)

Metallic aggregates with a size of a few tens ?m and consisting mainly of Ru, Rh, Pd, Te, Pb, As, Sb, S and Bi were found in the acid residue of SD37-S2/CD uraninite taken from Oklo natural reactor zone (RZ) 13. Quantitative analyses of major elements using an electron probe microanalyzer and in situ isotopic analyses of Zr, Mo, Ru, Pb and U using a sensitive high-resolution ion microprobe were performed on the metallic aggregates to determine the geochemical behaviors of fission products and actinides and to ascertain the processes of formation of the aggregates in the RZs. The chemical compositions of the aggregates investigated in this study are significantly different from those reported previously, showing lower Pb content and no correlation between the contents of Pb and S in the individual grains. The 235U/ 238U ratios in metallic aggregates vary significantly from 0.00478 to 0.01466, indicating chemical fractionation between U and Pu during the formation of the aggregates. The Pb isotopic data indicate that most of the Pb in the aggregates decayed from 2.05 Ga-old uraninite that existed in the RZ originally and that there was chemical fractionation between U and Pb in some aggregates. The Zr and Mo isotopic ratios, 90Zr/ 91Zr and 95Mo/ 97Mo, for most of the aggregates had small variations, which can be simply explained by constant separate mixing of fissiogenic and nonfissiogenic components. On the other hand, a large variation in the 99Ru/ 101Ru ratio (0.324-1.73) cannot be explained only by a two component mixing theory; thus, chemical fractionation between Tc and Ru during the reactor criticality is suggested. The large variations in the 235U/ 238U and 99Ru/ 101Ru isotopic ratios suggest that the aggregates formed under various redox conditions owing to the radiolysis of water.

Kikuchi, Makiko; Hidaka, Hiroshi; Gauthier-Lafaye, François



G2(+)M study on N-alkylamino cation affinities of neutral main-group element hydrides: trends across the periodic table.  


We have made an extensive theoretical exploration of gas-phase N-alkylamino cation affinities (NAAMCA), including amino cation affinities (AMCA) and N-dimethylamino cation affinities (NDMAMCA), of neutral main-group element hydrides of groups 15-17 and periods 2-4 in the periodic table by using the G2(+)M method. Some similarities and differences are found between NAAMCA and the corresponding alkyl cation affinities (ACA) of H(n)X. Our calculations show that the AMCA and NDMAMCA are systematically lower than the corresponding proton affinities (PA) for H(n)X. In general, there is no linear correlation between NAAMCA and PA of H(n)X. Instead, the correlations exist only within the central elements X in period 2, or periods 3-4, which is significantly different from the reasonable correlations between ACA and PA for all H(n)X. NAAMCA (H(n)X) are weaker than NAAMCA (H(n-1)X(-)) by more than 700 kJ/mol and generally stronger than ACA (H(n)X), with three exceptions: H2ONR2(+)(R = H, Me) and HFNH2(+). These new findings can be rationalized by the negative hyperconjugation and Pauli repulsion. PMID:24738576

Geng, Song; Wu, Ding-Lu; Yang, Jing; Wei, Xi-Guang; Zhu, Jun; Zhang, Hai-Bo; Ren, Yi; Lau, Kai-Chung



Development and application of new iondashexchange techniques for the separation of the platinum group and other siderophile elements from geological samples.  


Two new aniondashexchange techniques have been developed for the separation of the platinum group elements Ru, Pd, Ir, Pt and the siderophile metals Re, Ag, Zn and Cd from geological samples following a NiS fire assay digestion procedure. Both methods are simple and permit the isolation of these elements in sufficient purity for quantitative analysis by isotope dilutiondashinductively coupled plasma mass spectrometry (ID-ICPMS) at yields of 75-95%. The high affinity of the considered elements to anion exchange resins allows the use of small (1.25 ml) columns even for the processing of 5-10 g sized silicate rock samples. Following fire assay digestion and dissolution of the NiS buttons in aqua regia, the samples are loaded onto the resin bed as solutions in 1 M HCl. After elution of the bulk sample matrix with dilute HCl and HNO(3), Zn and Cd are stripped from the column using 0.8 M HNO(3). Small amounts of bromine water are added to the dilute mineral acids for the stabilization of strongly retained Ir(IV). Following this, the iondashexchange techniques permit the sequential elution of Ag, Re and the PGE using 11 M HCl, 8 M HNO(3) and 13.5 M HNO(3). The iondashexchange methods have been applied to separation of Ru, Pd, Re, Ir and Pt from the geological reference material SU-la prior to concentration measurements by ID-ICPMS. Our analytical results are in good agreement with previously published data for this sample and display an external reproducibility (based upon repeat dissolutions) of approximately 2-10% for the elements considered in this study. PMID:18966788

Rehkämper, M; Halliday, A N



X-ray fluorescence in some rare earth and high Z elements excited by 661.6 keV g-rays  

NASA Astrophysics Data System (ADS)

The K-shell X-ray fluorescence cross sections are determined experimentally for 10 elements such as Pb, Hg, Ir, W, Lu, Tm, Dy, Tb, Gd and Nd at excitation energy of 661.6 keV associated with g-rays of 137Cs radioisotope. The technique employed involves the measurement of total intensity of fluorescent K X-rays that follow the photoeffect absorption of a known flux of g-rays using a well type NaI(Tl) detector. The obtained results are compared with the available theoretical values and other measured values.

Yashoda, T.; Krishnaveni, S.; Gowda, Shivalinge; Umesh, T. K.; Gowda, Ramakrishna



A preliminary report on x-ray photoabsorption coefficients and atomic scattering factors for 92 elements in the 10--10,000 eV region  

SciTech Connect

Based on currently available photoabsorption measurements and recent theoretical calculations by Doolen and Liberman, a revised best-fit determination of the photoabsorption cross sections is presented here for the elements Z = 1 to Z = 92 in the 10--10,000 eV range. The photoabsorption data used include those described in the Lockheed and DOE listings of research abstracts for the past ten years and those which have been recently added to the comprehensive NBS Measured data Base. The best-fit curves are compared with both the compilation of measurements and the calculations by Doolen and Liberman. Using the photoabsorption curves, the atomic scattering factors have been calculated for the energy range 50--10,000 eV and are also presented in this report.

Henke, B.L.; Davis, J.C.; Gullikson, E.M.; Perera, R.C.C.



First measurement of the ratio B(t --> Wb)/B(t --> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element /V(tb)/.  


We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrt[s] = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity. PMID:11327939

Affolder, T; Akimoto, H; Akopian, A; Albrow, M G; Amaral, P; Amendolia, S R; Amidei, D; Anikeev, K; Antos, J; Apollinari, G; Arisawa, T; Asakawa, T; Ashmanskas, W; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bailey, M W; Bailey, S; de Barbaro, P; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Barone, M; Bauer, G; Bedeschi, F; Belforte, S; Bell, W H; Bellettini, G; Bellinger, J; Benjamin, D; Bensinger, J; Beretvas, A; Berge, J P; Berryhill, J; Bevensee, B; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Blusk, S R; Bocci, A; Bodek, A; Bokhari, W; Bolla, G; Bonushkin, Y; Bortoletto, D; Boudreau, J; Brandl, A; van den Brink, S; Bromberg, C; Brozovic, M; Bruner, N; Buckley-Geer, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Byon-Wagner, A; Byrum, K L; Calafiura, P; Campbell, M; Carithers, W; Carlson, J; Carlsmith, D; Caskey, W; Cassada, J; Castro, A; Cauz, D; Cerri, A; Chan, A W; Chang, P S; Chang, P T; Chapman, J; Chen, C; Chen, Y C; Cheng, M T; Chertok, M; Chiarelli, G; Chirikov-Zorin, I; Chlachidze, G; Chlebana, F; Christofek, L; Chu, M L; Chung, Y S; Ciobanu, C I; Clark, A G; Connolly, A; Conway, J; Cordelli, M; Cranshaw, J; Cronin-Hennessy, D; Cropp, R; Culbertson, R; Dagenhart, D; D'Auria, S; DeJongh, F; Dell'Agnello, S; Dell'Orso, M; Demortier, L; Deninno, M; Derwent, P F; Devlin, T; Dittmann, J R; Donati, S; Done, J; Dorigo, T; Eddy, N; Einsweiler, K; Elias, J E; Engels, E; Erbacher, R; Errede, D; Errede, S; Fan, Q; Feild, R G; Fernandez, J P; Ferretti, C; Field, R D; Fiori, I; Flaugher, B; Foster, G W; Franklin, M; Freeman, J; Friedman, J; Fukui, Y; Furic, I; Galeotti, S; Gallinaro, M; Gao, T; Garcia-Sciveres, M; Garfinkel, A F; Gatti, P; Gay, C; Gerdes, D W; Giannetti, P; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldstein, J; Gordon, A; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Green, C; Grim, G; Gris, P; Groer, L; Grosso-Pilcher, C; Guenther, M; Guillian, G; Da Costa, J G; Haas, R M; Haber, C; Hafen, E; Hahn, S R; Hall, C; Handa, T; Handler, R; Hao, W; Happacher, F; Hara, K; Hardman, A D; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Heinrich, J; Heiss, A; Herndon, M; Hill, C; Hoffman, K D; Holck, C; Hollebeek, R; Holloway, L; Hughes, R; Huston, J; Huth, J; Ikeda, H; Incandela, J; Introzzi, G; Iwai, J; Iwata, Y; James, E; Jensen, H; Jones, M; Joshi, U; Kambara, H; Kamon, T; Kaneko, T; Karr, K; Kasha, H; Kato, Y; Keaffaber, T A; Kelley, K; Kelly, M; Kennedy, R D; Kephart, R; Khazins, D; Kikuchi, T; Kilminster, B; Kim, B J; Kim, D H; Kim, H S; Kim, M J; Kim, S H; Kim, Y K; Kirby, M; Kirk, M; Kirsch, L; Klimenko, S; Koehn, P; Köngeter, A; Kondo, K; Konigsberg, J; Kordas, K; Korn, A; Korytov, A; Kovacs, E; Kroll, J; Kruse, M; Kuhlmann, S E; Kurino, K; Kuwabara, T; Laasanen, A T; Lai, N; Lami, S; Lammel, S; Lamoureux, J I; Lancaster, J; Lancaster, M; Lander, R; Latino, G; LeCompte, T; Lee, A M; Lee, K; Leone, S; Lewis, J D; Lindgren, M; Liss, T M; Liu, J B; Liu, Y C; Litvintsev, D O; Lobban, O; Lockyer, N; Loken, J; Loreti, M; Lucchesi, D; Lukens, P; Lusin, S; Lyons, L; Lys, J; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Mangano, M; Mariotti, M; Martignon, G; Martin, A; Matthews, J A; Mayer, J; Mazzanti, P; McFarland, K S; McIntyre, P; McKigney, E; Menguzzato, M; Menzione, A; Mesropian, C; Meyer, A; Miao, T; Miller, R; Miller, J S; Minato, H; Miscetti, S; Mishina, M; Mitselmakher, G; Moggi, N; Moore, E; Moore, R; Morita, Y; Moulik, T; Mulhearn, M; Mukherjee, A; Muller, T; Munar, A; Murat, P; Murgia, S; Nachtman, J; Nagaslaev, V; Nahn, S; Nakada, H; Nakaya, T; Nakano, I; Nelson, C; Nelson, T; Neu, C; Neuberger, D; Newman-Holmes, C; Ngan, C Y; Niu, H; Nodulman, L; Nomerotski, A; Oh, S H; Ohmoto, T; Ohsugi, T; Oishi, R; Okusawa, T; Olsen, J; Orejudos, W; Pagliarone, C; Palmonari, F; Paoletti, R; Papadimitriou, V; Pappas, S P; Partos, D; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pescara, L; Phillips, T J; Piacentino, G; Pitts, K T; Pompos, A; Pondrom, L; Pope, G; Popovic, M; Prokoshin, F; Proudfoot, J; Ptohos, F; Pukhov, O; Punzi, G; Ragan, K; Rakitine, A; Reher, D; Reichold, A; Ribon, A; Riegler, W; Rimondi, F; Ristori, L; Riveline, M; Robertson, W J; Robinson, A; Rodrigo, T; Rolli, S; Rosenson, L; Roser, R; Rossin, R; Roy, A; Safonov, A; St Denis, R; Sakumoto, W K; Saltzberg, D; Sanchez, C; Sansoni, A; Santi, L; Sato, H; Savard, P; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Scodellaro, L; Scott, A; Scribano, A; Segler, S; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Shah, T; Shapiro, M D; Shepard, P F; Shibayama, T; Shimojima, M; Shochet, M; Siegrist, J; Sill, A; Sinervo, P; Singh, P; Slaughter, A J; Sliwa, K; Smith, C; Snider, F D; Solodsky, A; Spalding, J; Speer, T; Sphicas, P; Spinella, F; Spiropulu, M; Spiegel, L; Steele, J; Stefanini, A; Strologas, J; Strumia, F; Stuart, D; Sumorok, K; Suzuki, T



The UV/optical spectra of the Type Ia supernova SN 2010jn: a bright supernova with outer layers rich in iron-group elements  

NASA Astrophysics Data System (ADS)

Radiative transfer studies of Type Ia supernovae (SNe Ia) hold the promise of constraining both the density profile of the SN ejecta and its stratification by element abundance which, in turn, may discriminate between different explosion mechanisms and progenitor classes. Here we analyse the Type Ia SN 2010jn (PTF10ygu) in detail, presenting and evaluating near-ultraviolet (near-UV) spectra from the Hubble Space Telescope and ground-based optical spectra and light curves. SN 2010jn was discovered by the Palomar Transient Factory (PTF) 15 d before maximum light, allowing us to secure a time series of four near-UV spectra at epochs from -10.5 to +4.8 d relative to B-band maximum. The photospheric near-UV spectra are excellent diagnostics of the iron-group abundances in the outer layers of the ejecta, particularly those at very early times. Using the method of `Abundance Tomography' we derive iron-group abundances in SN 2010jn with a precision better than in any previously studied SN Ia. Optimum fits to the data can be obtained if burned material is present even at high velocities, including significant mass fractions of iron-group elements. This is consistent with the slow decline rate (or high `stretch') of the light curve of SN 2010jn, and consistent with the results of delayed-detonation models. Early-phase UV spectra and detailed time-dependent series of further SNe Ia offer a promising probe of the nature of the SN Ia mechanism.

Hachinger, S.; Mazzali, P. A.; Sullivan, M.; Ellis, R. S.; Maguire, K.; Gal-Yam, A.; Howell, D. A.; Nugent, P. E.; Baron, E.; Cooke, J.; Arcavi, I.; Bersier, D.; Dilday, B.; James, P. A.; Kasliwal, M. M.; Kulkarni, S. R.; Ofek, E. O.; Laher, R. R.; Parrent, J.; Surace, J.; Yaron, O.; Walker, E. S.



On Same-Invariant Linear Groups  

Microsoft Academic Search

A linear group G=GL(V) is called same-invariant if the subspaces of linear invariants Vg are the same for all g?G,g?. Properties of such a group G under the assumption that G contains unipotent elements are considered. Bibliography: 7 titles.

N. L. Gordeev; N. F. Kushpel



[1] V. A. Voevodskii. Galois group Gal( Q/Q) and Teihmuller modular groups. In Proc. Conf. Constr. Methods and Alg. Number Theory, Minsk, 1989.  

E-print Network

of oriented manifolds and ramified coverings of sphere (in Russian). In Proc. Conf. of Young Scientists. Multidimensional categories (in Russian). In Proc. Conf. of Young Scientists. Moscow Univ. Press, 1990. [9] V. A


Platinum-group element, Gold, Silver and Base Metal distribution in compositionally zoned sulfide droplets from the Medvezky Creek Mine, Noril'sk, Russia  

USGS Publications Warehouse

Concentrations of Ag, Au, Cd, Co, Re, Zn and Platinum-group elements (PGE) have been determined in sulfide minerals from zoned sulfide droplets of the Noril'sk 1 Medvezky Creek Mine. The aims of the study were; to establish whether these elements are located in the major sulfide minerals (pentlandite, pyrrhotite, chalcopyrite and cubanite), to establish whether the elements show a preference for a particular sulfide mineral and to investigate the model, which suggests that the zonation in the droplets is caused by the crystal fractionation of monosulfide solid solution (mss). Nickel, Cu, Ag, Re, Os, Ir, Ru, Rh and Pd, were found to be largely located in the major sulfide minerals. In contrast, less than 25% of the Au, Cd, Pt and Zn in the rock was found to be present in these sulfides. Osmium, Ir, Ru, Rh and Re were found to be concentrated in pyrrhotite and pentlandite. Palladium and Co was found to be concentrated in pentlandite. Silver, Cd and Zn concentrations are highest in chalcopyrite and cubanite. Gold and platinum showed no preference for any of the major sulfide minerals. The enrichment of Os, Ir, Ru, Rh and Re in pyrrhotite and pentlandite (exsolution products of mss) and the low levels of these elements in the cubanite and chalcopyrite (exsolution products of intermediate solid solution, iss) support the mss crystal fractionation model, because Os, Ir, Ru, Rh and Re are compatible with mss. The enrichment of Ag, Cd and Zn in chalcopyrite and cubanite also supports the mss fractionation model these minerals are derived from the fractionated liquid and these elements are incompatible with mss and thus should be enriched in the fractionated liquid. Gold and Pt do not partition into either iss or mss and become sufficiently enriched in the final fractionated liquid to crystallize among the iss and mss grains as tellurides, bismithides and alloys. During pentlandite exsolution Pd appears to have diffused from the Cu-rich portion of the droplet into pentlandite. ?? Springer-Verlag 2006.

Barnes, S.-J.; Cox, R.A.; Zientek, M.L.



POWER SUPPLY SYSTEM FOR CORRECTING MAGNETS OF VEPP-2000 O. Belikov, D. Berkaev, V. Kozak, A. Medvedko, BINP, Novosibirsk, Russia  

E-print Network

is regulated with pulse-width modulation of the output voltage of a bridge inverter with a conversion frequency these correcting elements differ in active resistance, they were grouped in accordance with voltage drop, which gave five groups with the following output voltage: up to 32V, up to 40V, up to 48V, up to 64V and up

Kozak, Victor R.


Neutron and proton transition matrix elements for 90Zr from a microscopic analysis of 0.8 GeV proton inelastic scattering  

NASA Astrophysics Data System (ADS)

We have analyzed recent 0.8 GeV proton inelastic scattering cross sections for eight low-lying states in 90Zr using the distorted wave impulse approximation and transition densities from a large basis shell model calculation. The shell model basis consists of the configurations of 12 valence protons in the 2p12, 2p32, 1f52, and 1g92 orbits. In general the shapes of the cross sections are well reproduced, but the calculated transition amplitudes must be multiplied by factors of 2.2 to 4.6 to fit the magnitudes. These enhancement factors are larger than those required for the B(E?) values derived from electron scattering, indicating large neutron components in these states. We argue that transitions to the 3-1 and 2+3 states cannot be described adequately in the chosen shell model basis. From the proton and electromagnetic enhancement factors we are able to obtain estimates of the missing "core" neutron and proton matrix elements. NUCLEAR REACTIONS 90Zr(p,p') at 0.8 GeV, analyzed with DWIA and shell model theory. B(E?) values calculated. Neutron and proton core matrix elements deduced.

Gazzaly, M. M.; Hintz, N. M.; Franey, M. A.; Dubach, J.; Haxton, W. C.



Fragmentation cross sections of 290 and 400 MeV\\/nucleon C12 beams on elemental targets  

Microsoft Academic Search

Charge-changing and fragment production cross sections at 0° have been obtained for interactions of 290 and 400 MeV\\/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. These beams are relevant to cancer therapy, space radiation, and the production of radioactive beams. We compare these results against previously published results using C and CH2 targets at similar beam

C. Zeitlin; S. Guetersloh; L. Heilbronn; J. Miller; A. Fukumura; Y. Iwata; T. Murakami



Investigation of (n,alpha) Reaction for Rare-earth Elements in the MeV Neutron Energy Region  

SciTech Connect

Cross sections and forward/backward ratios in the laboratory reference system were measured for {sup 143}Nd(n, {alpha}){sup 140}Ce at 4.0, 5.0, and 6.0 MeV, {sup 147}Sm(n, {alpha}){sup 144}Nd at 5.0 and 6.0 MeV, and {sup 149}Sm(n, {alpha}){sup 146}Nd at 6.0 MeV. A twin gridded ionization chamber and large-area back-to-back {sup 143}Nd{sub 2}O{sub 3} and {sup 147,149}Sm{sub 2}O{sub 3} samples were employed. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was employed for absolute neutron flux determination and a BF{sub 3} long counter was used as neutron flux monitor. Present experimental data are compared with previous measurements, evaluations, and model calculations.

Gledenov, R. Y. [Joint Institute for Nuclear Research, Dubna, Russia; Koehler, Paul Edward [ORNL; N_TOF collaboration, [CNR-INFM, Trieste, Italy



Comparative mitochondrial genomics in zygomycetes: bacteria-like RNase P RNAs, mobile elements and a close source of the group I intron invasion in angiosperms  

PubMed Central

To generate data for comparative analyses of zygomycete mitochondrial gene expression, we sequenced mtDNAs of three distantly related zygomycetes, Rhizopus oryzae, Mortierella verticillata and Smittium culisetae. They all contain the standard fungal mitochondrial gene set, plus rnpB, the gene encoding the RNA subunit of the mitochondrial RNase P (mtP-RNA) and rps3, encoding ribosomal protein S3 (the latter lacking in R.oryzae). The mtP-RNAs of R.oryzae and of additional zygomycete relatives have the most eubacteria-like RNA structures among fungi. Precise mapping of the 5? and 3? termini of the R.oryzae and M.verticillata mtP-RNAs confirms their expression and processing at the exact sites predicted by secondary structure modeling. The 3? RNA processing of zygomycete mitochondrial mRNAs, SSU-rRNA and mtP-RNA occurs at the C-rich sequence motifs similar to those identified in fission yeast and basidiomycete mtDNAs. The C-rich motifs are included in the mature transcripts, and are likely generated by exonucleolytic trimming of RNA 3? termini. Zygomycete mtDNAs feature a variety of insertion elements: (i) mtDNAs of R.oryzae and M.verticillata were subject to invasions by double hairpin elements; (ii) genes of all three species contain numerous mobile group I introns, including one that is closest to an intron that invaded angiosperm mtDNAs; and (iii) at least one additional case of a mobile element, characterized by a homing endonuclease insertion between partially duplicated genes [Paquin,B., Laforest,M.J., Forget,L., Roewer,I., Wang,Z., Longcore,J. and Lang,B.F. (1997) Curr. Genet., 31, 380–395]. The combined mtDNA-encoded proteins contain insufficient phylogenetic signal to demonstrate monophyly of zygomycetes. PMID:15689432

Seif, Elias; Leigh, Jessica; Liu, Yu; Roewer, Ingeborg; Forget, Lise; Lang, B. Franz



Measurement of the t-channel single-top-quark production cross section and of the | V tb| CKM matrix element in pp collisions at = 8 TeV  

NASA Astrophysics Data System (ADS)

Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb-1 recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop , in final states with a muon or an electron. The measured inclusive t-channel cross section is ? t-ch. = 83 .6 ± 2 .3 (stat.) ± 7 .4 (syst.) pb. The single t and cross sections are measured to be ? t-ch.( t) = 53 .8 ± 1 .5 (stat.) ± 4 .4 (syst.) pb and ? t-ch. = 27 .6 ± 1 .3 (stat.) ± 3 .7 (syst.) pb, respectively. The measured ratio of cross sections is R t-ch. = ? t-ch.(t) /? t-ch. = 1 .95 ± 0 .10 (stat.) ± 0 .19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element V tb is extracted and, in combination with a previous CMS result at = 7 TeV, a value | V tb| = 0 .998 ± 0 .038 (exp.) ± 0 .016 (theo.) is obtained. [Figure not available: see fulltext.

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Luyckx, S.; Ochesanu, S.; Roland, B.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Kalogeropoulos, A.; Keaveney, J.; Kim, T. J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Marage, P. E.; Mohammadi, A.; Perniè, L.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Klein, B.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jez, P.; Komm, M.; Lemaitre, V.; Liao, J.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins, M.; Dos Reis Martins, T.; Pol, M. E.; Aldá, W. L.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Malek, M.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Du, R.; Jiang, C. H.; Liang, D.; Liang, S.; Plestina, R.; Tao, J.; Wang, X.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, Y.; Li, Q.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Morovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Nayak, A.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Salerno, R.; Sauvan, J. b.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.



Multireference - M?ller-Plesset Perturbation Theory Results on Levels and Transition Rates in Al-like Ions of Iron Group Elements  

SciTech Connect

Ground configuration and low-lying levels of Al-like ions contribute to a variety of laboratory and solar spectra, but the available information in databases are neither complete not necessarily correct. We have performed multireference Moeller-Plesset perturbation theory calculations that approach spectroscopic accuracy in order to check the information that databases hold on the 40 lowest levels of Al-Like ions of iron group elements (K through Ge), and to provide input for the interpretation of concurrent experiments. Our results indicate problems of the database holdings on the levels of the lowest quartet levels in the lighter elements of the range studied. The results of our calculations of the decay rates of five long-lived levels (3s{sup 2}3p {sup 2}p{sup o}{sub 3/2}, 3s3p{sup 2} {sup 4}P{sup o} J and 3s3p3d {sup 4}F{sup o}{sub 9/2}) are compared with lifetime data from beam-foil, electron beam ion trap and heavy-ion storage ring experiments.

Santana, J A; Ishikawa, Y; Tr?abert, E



Small carbides of third-row main group elements: structure and bonding in C3X compounds (X = K-Br).  


The molecular structures of third-row main group tricarbides C(3)X (X = K-Br) have been studied by quantum chemical methods. It is found that less electronegative elements (K, Ca, Ga, Ge) favor either fan or rhombic structures (resulting from side interactions with either linear or triangular C(3) units), whereas the more electronegative elements (As, Se, Br) favor linear or three-membered ring structures (resulting from ?-type interactions with either linear or triangular C(3) units). The predicted global minima are of fan type for C(3)K, rhombic for C(3)Ca, C(3)Ga, and C(3)Ge, linear for C(3)As and C(3)Se, and a three-membered ring for C(3)Br. In order to aid in their possible experimental identification the molecular geometries, vibrational frequencies, IR intensities, and dipole moments have been provided. The nature of the interactions has been characterized through an analysis of the electronic charge density. In addition, the relative stability of the different isomers has been also rationalized in terms of an energy decomposition analysis. PMID:23034393

Villanueva, Estefanía F; Redondo, Pilar; Rayón, Víctor M; Barrientos, Carmen; Largo, Antonio



Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the post-d main group elements Ga-Rn  

NASA Astrophysics Data System (ADS)

New correlation consistent basis sets, cc-pVnZ-PP-F12 (n = D, T, Q), for all the post-d main group elements Ga-Rn have been optimized for use in explicitly correlated F12 calculations. The new sets, which include not only orbital basis sets but also the matching auxiliary sets required for density fitting both conventional and F12 integrals, are designed for correlation of valence sp, as well as the outer-core d electrons. The basis sets are constructed for use with the previously published small-core relativistic pseudopotentials of the Stuttgart-Cologne variety. Benchmark explicitly correlated coupled-cluster singles and doubles with perturbative triples [CCSD(T)-F12b] calculations of the spectroscopic properties of numerous diatomic molecules involving 4p, 5p, and 6p elements have been carried out and compared to the analogous conventional CCSD(T) results. In general the F12 results obtained with a n-zeta F12 basis set were comparable to conventional aug-cc-pVxZ-PP or aug-cc-pwCVxZ-PP basis set calculations obtained with x = n + 1 or even x = n + 2. The new sets used in CCSD(T)-F12b calculations are particularly efficient at accurately recovering the large correlation effects of the outer-core d electrons.

Hill, J. Grant; Peterson, Kirk A.



Noncoding transcription within the Igh distal V(H) region at PAIR elements affects the 3D structure of the Igh locus in pro-B cells.  


Noncoding sense and antisense germ-line transcription within the Ig heavy chain locus precedes V(D)J recombination and has been proposed to be associated with Igh locus accessibility, although its precise role remains elusive. However, no global analysis of germ-line transcription throughout the Igh locus has been done. Therefore, we performed directional RNA-seq, demonstrating the locations and extent of both sense and antisense transcription throughout the Igh locus. Surprisingly, the majority of antisense transcripts are localized around two Pax5-activated intergenic repeat (PAIR) elements in the distal IghV region. Importantly, long-distance loops measured by chromosome conformation capture (3C) are observed between these two active PAIR promoters and E?, the start site of I? germ-line transcription, in a lineage- and stage-specific manner, even though this antisense transcription is E?-independent. YY1(-/-) pro-B cells are greatly impaired in distal V(H) gene rearrangement and Igh locus compaction, and we demonstrate that YY1 deficiency greatly reduces antisense transcription and PAIR-E? interactions. ChIP-seq shows high level YY1 binding only at E?, but low levels near some antisense promoters. PAIR-E? interactions are not disrupted by DRB, which blocks transcription elongation without disrupting transcription factories once they are established, but the looping is reduced after heat-shock treatment, which disrupts transcription factories. We propose that transcription-mediated interactions, most likely at transcription factories, initially compact the Igh locus, bringing distal V(H) genes close to the DJ(H) rearrangement which is adjacent to E?. Therefore, we hypothesize that one key role of noncoding germ-line transcription is to facilitate locus compaction, allowing distal V(H) genes to undergo efficient rearrangement. PMID:23027941

Verma-Gaur, Jiyoti; Torkamani, Ali; Schaffer, Lana; Head, Steven R; Schork, Nicholas J; Feeney, Ann J



Revised Energy Spectra for Primary Elements, H - Si, above 50 GeV from the ATIC-2 Science Flight  

NASA Technical Reports Server (NTRS)

The Advanced Thin Ionization Calorimeter (ATIC) long duration balloon experiment had a successful science flight accumulating 18 days of data (12/02 - 1/03) during a single circumnavigation in Antarctica. ATIC measures the energy spectra of elements from H to Fe in primary cosmic rays using a fully active Bismuth Germanate calorimeter preceded by a carbon target, with embedded scintillator hodoscopes, and a silicon matrix charge detector at the top. Preliminary results from ATIC have been reported in previous conferences. The revised results reported here are derived from a new analysis of the data with improved charge resolution, lower background and revised energy calibration. The raw energy deposit spectra are de-convolved into primary energy spectra and extrapolated to the top of the atmosphere. We compare these revised results to previous data and comment upon the astrophysical interpretation of the results.

Wefel, J. P.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Chang, J.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunashingha, R. M.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kouznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya, N. V.; Watts, J. W.; Wu, J.; Zatsepin, V. I.



First principles DFT study of ferromagnetism in SnO2 induced by doped group 1A and 2A non-magnetic elements X (X=Li, Na, K, Be, Mg, Ca)  

NASA Astrophysics Data System (ADS)

Transition metal - free - ferromagnetism in diluted magnetic semiconductors (DMS) is of much current interest in the search for more efficient DMS materials for spintronic applications. Here, we report the results of our first principles density functional theory (DFT) study on impurity - induced ferromagnetism in non-magnetic SnO2 by a non-magnetic impurity. The impurities considered are sp-type of group 1A and 2A elements X (X = Li, Na, K, Be, Mg, Ca). Even a single atom of the group 1A elements makes the system magnetic, whereas for the group 2A elements Ca and Mg, a higher doping is required to induce ferromagnetism. For all the elements studied, the magnetic moment appears to increase with the doping concentration, at least at certain impurity separations, which is a positive indicator for practical applications.

Chakraborty, Brahmananda; Ramaniah, Lavanya M.



Ir, Ru, Pt, and Pd in basalts and komatiites: New constraints for the geochemical behavior of the platinum-group elements in the mantle  

SciTech Connect

The concentrations of the platinum-group elements (PGE) Ir, Ru, Pt, and Pd were determined in 18 mantle-derived basalts from a variety of tectonic settings and six komatiites from three locations. All analyses were performed using isotope dilution, Carius tube digestion, and the precise technique of multiple collector inductively coupled plasma mass spectrometry. Multiple analyses of two samples indicate external reproducibilities, based upon separate dissolutions, or approximately 2--9% in the ppt to ppb concentration range. Mid-ocean ridge basalts from the Kolbeinsey Ridge, tholeiites from Iceland and alkali basalts from the Cameroon Line define three individual samples suites that are characterized by distinct major, trace, and platinum-group element systematics. All three-sample suites display correlations of the PGE with MgO, Ni, and Cr. The new analytical results are employed to constrain the geochemical behavior of the PGE during the formation and differentiation of mantle-derived melts. The PGE are inferred to be compatible in sulfides during partial melting with sulfide-silicate melt partition coefficients of {approximately}1 x 10{sup 4}. The fractionated PGE patterns of mantle melts re a consequence of the incompatibility of Pd in nonsulfide phases, whereas Ir and Ru must be compatible in at least one other mantle phase. Model calculations indicate that PGE alloys or spinel may be responsible for the higher compatibility of the latter elements during partial melting. It is further demonstrated that the shape of the melting regime has a profound effect on the PGE systematics of mantle magmas. The systematic trends of the three samples suites in plots of PGE against Ni and Cr are the results of magma differentiation processes that involve fractional crystallization of silicate minerals and the concurrent segregation of an immiscible sulfide liquid. The behavior of the PGE during magma fractionation indicates that the segregated sulfides probably equilibrate with {gt}90% of the silicate magma and that PGE scavenging by sulfides is best described by a combination of batch and fractional equilibrium partitioning.

Rehkaemper, M.; Halliday, A.N.; Fitton, J.G.; Lee, D.C.; Wieneke, M.; Arndt, N.T.



Ectomycorrhizal Influence on Particle Size, Surface Structure, Mineral Crystallinity, Functional Groups, and Elemental Composition of Soil Colloids from Different Soil Origins  

PubMed Central

Limited data are available on the ectomycorrhizae-induced changes in surface structure and composition of soil colloids, the most active portion in soil matrix, although such data may benefit the understanding of mycorrhizal-aided soil improvements. By using ectomycorrhizae (Gomphidius viscidus) and soil colloids from dark brown forest soil (a good loam) and saline-alkali soil (heavily degraded soil), we tried to approach the changes here. For the good loam either from the surface or deep soils, the fungus treatment induced physical absorption of covering materials on colloid surface with nonsignificant increases in soil particle size (P > 0.05). These increased the amount of variable functional groups (O–H stretching and bending, C–H stretching, C=O stretching, etc.) by 3–26% and the crystallinity of variable soil minerals (kaolinite, hydromica, and quartz) by 40–300%. However, the fungus treatment of saline-alkali soil obviously differed from the dark brown forest soil. There were 12–35% decreases in most functional groups, 15–55% decreases in crystallinity of most soil minerals but general increases in their grain size, and significant increases in soil particle size (P < 0.05). These different responses sharply decreased element ratios (C?:?O, C?:?N, and C?:?Si) in soil colloids from saline-alkali soil, moving them close to those of the good loam of dark brown forest soil. PMID:23766704

Li, Yanhong; Wang, Huimei; Wang, Wenjie; Yang, Lei; Zu, Yuangang



Interaction of transuranium elements with biologically important molecules: structural and spectroscopic study of NP(V) complexes with imidazole.  


New Np(V) complexes with imidazole, [NpO(2)(CH(3)COO)(Im)(2)(H(2)O)], [(NpO(2))(2)(C(2)O(4))(Im)(6)] x 5 Im x H(2)O, and [NpO(2)(NO(2))(Im)(4)], were synthesized. Their crystal structures were determined using X-ray single-crystal diffractometry. The crystal structures are confirmed by IR and UV-vis spectroscopic data. In all three complexes, neptunium coordinates the imidazole molecule through the nitrogen atom. These complexes are the first example of direct bonding of the imidazole molecule to the actinide atom. These results suggest that coordination of histidine residue in proteins or other imidazole-containing biologically important molecules could occur under usual biological conditions. PMID:19166371

Andreev, Grigory B; Budantseva, Nina A; Tananaev, Ivan G; Myasoedov, Boris F



Reuter, C., Heger, O., Pipek, V. (2012): Social Media for Supporting Emergent Groups in Crisis Management. In: Proceedings of the CSCW Workshop on  

E-print Network

84 Reuter, C., Heger, O., Pipek, V. (2012): Social Media for Supporting Emergent Groups in Crisis Reports on Socio Informatics, Vol. 9, No. 2, pp. 84-92 (ISSN: 1861-4280) Social Media for, 3 Abstract. The great importance of Social Media for our today's life


Uncertainty Principles for Compact Groups  

E-print Network

We establish an operator-theoretic uncertainty principle over arbitrary compact groups, generalizing several previous results. As a consequence, we show that if f is in L^2(G), then the product of the measures of the supports of f and its Fourier transform ^f is at least 1; here, the dual measure is given by the sum, over all irreducible representations V, of d_V rank(^f(V)). For finite groups, our principle implies the following: if P and R are projection operators on the group algebra C[G] such that P commutes with projection onto each group element, and R commutes with left multiplication, then the squared operator norm of PR is at most rank(P)rank(R)/|G|.

Gorjan Alagic; Alexander Russell



K and L-shell X-ray production cross sections for 50-250 keV proton impact on elements with Z = 26-30  

NASA Astrophysics Data System (ADS)

The K and L-shell X-ray production cross sections of Fe, Co, Ni, Cu and Zn elements are measured by 50-250 keV proton impact. The results are compared with Binary Encounter Approximation (BEA), Plane Wave Born Approximation (PWBA) and Energy loss Coulomb repulsion Perturbed Stationary State Relativistic (ECPSSR) theoretical predictions, as well as with experimental data of other authors. The ECPSSR theory agrees well with the K-shell cross section, but it overestimates the L-shell cross section by a maximum factor of about 7. The ECPSSR theory predicts a good trend to the production cross section ratio of the L to K-shell X-ray.

Zhou, Xianming; Zhao, Yongtao; Cheng, Rui; Wang, Yuyu; Lei, Yu; Wang, Xing; Sun, Yuanbo



Spatial distribution of major and trace elements in the water of Swarzedzkie Lake (Poland).  


In order to characterize the contamination of the Swarzedzkie Lake and generate elemental distribution patterns 18 elements have been determined in samples of water, taken just above the bottom sediments. Analyses were carried out using two instrumental techniques - ICP-OES and ICP-MS. Two main sources of contamination were identified - diffuse pollution from agriculture and stormwater from the town. Three separate groups of elements were distinguished using cluster analysis and two groups using principal component analysis. These three groups are characterized as geogenic elements (Ag, As, Mg and Sb), elements supplied by the agricultural catchment (Ca, Mn, Sr, Na, K and Al) and elements originated from the urban contamination (Ni, Cr, Cu, Fe, V, Ba, Zn and Pb). PCA differentiated the above group of urban elements from the rest, originated from diffuse sources, with exception of alluminium, which was situated between two distinguished groups. PMID:17912598

Bara?kiewicz, Danuta; Gramowska, Hanka; Kanecka, Anetta; Krzyzaniak, Izabela; Go?dyn, Ryszard



Fragmentation cross sections of 290 and 400 MeV/nucleon C12 beams on elemental targets  

NASA Astrophysics Data System (ADS)

Charge-changing and fragment production cross sections at 0° have been obtained for interactions of 290 and 400 MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. These beams are relevant to cancer therapy, space radiation, and the production of radioactive beams. We compare these results against previously published results using C and CH2 targets at similar beam energies. Because of ambiguities arising from the presence of multiple fragments on many events, the previous publications reported only cross sections for B and Be fragments. In this work, we have extracted cross sections for all fragment species, using data obtained at three distinct values of angular acceptance, supplemented by data taken with the detector stack placed off the beam axis. A simulation of the experiment with the particle and heavy ion transport system (PHITS) Monte Carlo model shows fair agreement with the data obtained with the large-acceptance detectors, but agreement is poor at small acceptance. The measured cross sections are also compared with the predictions of the one-dimensional cross section models EPAX2 and NUCFRG2; the latter is presently used in NASA's space radiation transport calculations. Though PHITS and NUCFRG2 reproduce the charge-changing cross sections with reasonable accuracy, none of the models is able to accurately predict the fragment cross sections for all fragment species and target materials.

Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura, A.; Iwata, Y.; Murakami, T.



Synthesis, surface group modification of 3D MnV{sub 2}O{sub 6} nanostructures and adsorption effect on Rhodamine B  

SciTech Connect

Highlights: ? Fabrication of urchin-like MnV{sub 2}O{sub 6} with oxygen-containing surface groups. ? Mn{sub 0.5}V{sub 2}O{sub 5}·nH{sub 2}O as an intermediate product holds the key to the final products. ? 3D architectures of MnV{sub 2}O{sub 6} with oxygen-containing surface groups as sorbent. ? The sorbent shows a good adsorption ability. -- Abstract: Highly uniform 3D MnV{sub 2}O{sub 6} nanostructures modified by oxygen functional groups (-COO-) were successfully prepared in large quantities by an approach involving preparation of vanadyl ethylene glycolate as the precursor. The growth and self-assembly of MnV{sub 2}O{sub 6} nanobelts and nanorods could be readily tuned by additive species and quantities, which brought different morphologies and sizes to the final products. With a focus on the regulation of structure, the formation process of 3D architectures of MnV{sub 2}O{sub 6} by self-assembly of nanobelts was followed by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The consecutive processes of vanadyl ethylene glycolate and benzoyl peroxide assisted formation of layered structure Mn{sub 0.5}V{sub 2}O{sub 5}·nH{sub 2}O, growth of aligned MnV{sub 2}O{sub 6} nanobelts, and oriented assembly were proposed for the growth mechanism. The band gap vs. different morphology was also studied. Optical characterization of these MnV{sub 2}O{sub 6} with different morphologies showed direct bandgap energies at 1.8–1.95 eV. The adsorption properties of 3D MnV{sub 2}O{sub 6} nanostructures synthesized under different conditions were investigated through the removal test of Rhodamine B in aqueous water, and the 3D nanostructures synthesized with 30 g L{sup ?1} benzoyl peroxide showed good adsorption capability of Rhodamine B.

Zhang, Wanqun, E-mail: [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China) [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chemical Experimental Teaching Center, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, Lei, E-mail: [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang, Kaibin; Liu, Zhongping [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China)



Structural Distortions in M[E(SiMe3)2]3 Complexes (M = Group 15, f-Element; E = N, CH): Is Three a Crowd?  


The tris(bistrimethylsilylamido) species P[N(SiMe3)2]3 (1) and As[N(SiMe3)2]3 (2) have been prepared through halide metathesis in high yield. Their single crystal X-ray structures, along with that of Sb[N(SiMe3)2]3 (3), complete the series of structurally authenticated group 15 M[N(SiMe3)2]3 complexes (the bismuth analogue (4) has been previously reported). All four complexes possess the expected pyramidal geometries, with progressively longer M-N bond distances from P to Bi but closely similar N-M-N angles (107-104°). The structures of 1-4 also display distortions that are similar to those in f-element M[N(SiMe3)2]3 and M[CH(SiMe3)2]3 complexes, in which M···(?-Si-C) interactions have been identified. Such structural features include distorted M-(N,CH)-Si and (N,CH)-Si-C angles and close M···C and M···Si contacts. DFT calculations confirm that there are no M···(?-Si-C) interactions in 1-4; the bond distortions appear to result from the particular steric crowding that arises in pyramidal M[(N,CH)(SiMe3)2]3 complexes. This is likely the source of the most of the distortions in the structures of the f-element analogues as well, even though the latter possess attractive M···Si-C interactions. PMID:25171144

Boyde, Nicholas C; Chmely, Stephen C; Hanusa, Timothy P; Rheingold, Arnold L; Brennessel, William W



Effects of mother lode-type gold mineralization on 187Os/188Os and platinum group element concentrations in peridotite: Alleghany District, California  

USGS Publications Warehouse

Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and barzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au abundances typical of the upper mantle at their presumed formation age during the late Proterozoic or early Paleozoic. The hydrothermally altered rocks have highly variable initial Os isotope compositions with ??os, values (% deviation of 187OS/188OS from the chondritic average calculated for the approx. 120 Ma time of mineralization) ranging from -1.4 to -8.3. The lowest Os isotope compositions are consistent with Re depletion of a chondritic source (e.g., the upper mantle) at ca. 1.6 Ga. Most of the altered samples are enriched in Au and have depleted and fractionated abundances of Re and PGE relative to their precursor peridotites. Geoehemical characteristics of the altered samples suggest that Re and some PGE were variably removed from the ultramafic rocks during the mineralization event. In addition to Re, the Pt and Pd abundances of the most intensely altered rocks appear to have been most affected by mineralization. The 187Os-depleted isotopic compositions of some altered rocks are interpreted to be a result of preferential 187Os loss via destruction of Re-rich phases during the event. For these rocks, Os evidently is not a useful tracer of the mineralizing fluids. The results do, however, provide evidence for differential mobility of these elements, and mobility of 187Os relative to the initial bulk Os isotope composition during hydrothermal metasomatic alteration of ultramafic rocks. ?? 2007 Society of Economic Geologists, Inc.

Walker, R. J.; Bohlke, J. K.; McDonough, W. F.; Li, J.



Platinum-group element (PGE) geochemistry of Mesoarchean ultramafic-mafic cumulate rocks and chromitites from the Nuasahi Massif, Singhbhum Craton (India)  

NASA Astrophysics Data System (ADS)

The Mesoarchean Nuasahi Massif in eastern India comprises a lower ultramafic and an upper gabbro unit. The lower unit consists of orthopyroxenite, harzburgite, dunite and three chromitite bands. All of these rocks are characterized by adcumulate textures. The upper unit consists of gabbro with magnetite layers. At the contact between the eastern orthopyroxenite and the lower part of the upper gabbro, a sulfide-rich breccia zone with platinum-group-element (PGE) mineralization is present. Detailed studies of major-, trace- and PGE abundances suggest that the ultramafic-mafic cumulate rocks, chromitites and breccias are genetically linked. The chondrite-normalized U-shaped rare earth element (REE) patterns of the harzburgite resemble those of Phanerozoic boninite. The overall U-shaped REE patterns of the ultramafic rocks indicate derivation of the parental magma from a metasomatized depleted mantle source. The upper gabbros have higher relative abundances of trace elements than the lower ultramafic rocks, due to crystallization from a fractionated magma. Whole-rock geochemistry suggests that the lower ultramafic cumulate rocks with chromitites crystallized from a boninitic parental magma, whereas the upper gabbros with magnetite bands may be formed from residual boninitic magma that was contaminated by more tholeiitic-like magmas. The boninitic parental magma that crystallized to form the lower ultramafic unit was most likely generated by second-stage melting of a depleted metasomatized mantle source in a supra-subduction zone (SSZ) setting and emplaced into crustal sequences. The PGE abundances in the Nuasahi rocks provide additional constraints on their geochemical evolution during the Mesoarchean. Primitive-mantle-normalized PGE diagrams show (1) Ru enrichment in chromitites (Pd/Ru = 0.17-0.64), (2) Pd/Pt fractionation in both chromitites (Pd/Pt = 3.1) and ultramafic rocks (Pd/Pt = 0.62), (3) marked Ir depletion in ultramafic rocks (Pd/Ir = 6.3) and (4) overall PGE enrichment in chromitites (PGEtotal = 142-502 ppb). The large Ir depletion in the ultramafic rocks, and the overall Ir-depleted character of other rocks from the Nuasahi Massif, may be related to multiple episodes of melt extraction from the mantle source, giving it a subchondritic character.

Khatun, Sarifa; Mondal, Sisir K.; Zhou, Mei-Fu; Balaram, Vysetti; Prichard, Hazel M.



Relatively Long-Lived Dubnium Isotopes and Chemical Identification of Superheavy Elements  

SciTech Connect

The present study has been performed within the framework of experiments aimed at the investigation of chemical properties of long-lived Db isotopes in aqueous solutions. The isocratic anion exchange separations of group V elements in the solutions containing HF have been considered. Parameters of separation of dubnium homologues (Pa, Nb and Ta) in HF/HNO{sub 3} mixed solutions have been optimized. The procedure of separation of group V elements from multicomponent system has been suggested.

Tereshatov, E. E.; Voronyuk, M. G.; Starodub, G. Ya.; Petrushkin, O. V.; Dmitriev, S. N. [Flerov Laboratory of Nuclear Reactions (FLNR), JINR, Dubna RU-141980 (Russian Federation); Bruchertseifer, H. [Paul Scherrer Institute (PSI), Villigen CH-5232 (Switzerland)



Group V phospholipase A2 mediates barrier disruption of human pulmonary endothelial cells caused by LPS in vitro.  


We examined the functional role of 14-kD secretory group V phospholipase A(2) (gVPLA(2)) on the barrier function of pulmonary endothelial cells (ECs) after LPS activation in vitro. Expression of gVPLA(2) was elicited by 20 ng/ml LPS as demonstrated by increased (1) mRNA, (2) protein content, and (3) cell surface expression of gVPLA(2) within 4 hours. The effect of LPS on EC barrier function was measured by transendothelial monolayer electrical resistance (TER). LPS increased permeability across EC monolayers at 2-3 hours, and was sustained for 10 hours or more. Blockade of gVPLA(2) with mouse monoclonal 3G1 (MCL-3G1) monoclonal antibody directed against gVPLA(2) inhibited EC barrier dysfunction elicited by LPS in a time- and concentration-dependent manner; control IgG had no effect on TER. Like LPS, exogenous gVPLA(2) caused increased EC permeability in a time- and concentration-dependent manner; neither gIIaPLA(2), a close homolog of gVPLA(2), nor W31A, an inactive mutant of gVPLA(2), caused a decrease in EC TER. Immunofluorescence analysis revealed comparable F-actin stress fiber and intercellular gap formation for ECs treated with either gVPLA(2) or LPS. Treatment with gVPLA(2) disrupted vascular endothelial-cadherin junctional complexes on ECs. Coincubation of ECs with MCL-3G1 substantially attenuated the structural changes caused by gVPLA(2) or LPS. We demonstrate that (1) gVPLA(2) is constitutively expressed in ECs and is up-regulated after LPS activation, (2) endogenously secreted gVPLA(2) from ECs after LPS increases EC permeability through F-actin and junctional complex rearrangement, and (3) inhibition of endogenous gVPLA(2) from ECs is sufficient to block disruption of the EC barrier function after LPS in vitro. PMID:20448053

Dudek, Steven M; Muñoz, Nilda M; Desai, Anjali; Osan, Christopher M; Meliton, Angelo Y; Leff, Alan R



ICEG2D (v2.0) - An Integrated Software Package for Automated Prediction of Flow Fields for Single-Element Airfoils With Ice Accretion  

NASA Technical Reports Server (NTRS)

An integrated geometry/grid/simulation software package, ICEG2D, is being developed to automate computational fluid dynamics (CFD) simulations for single- and multi-element airfoils with ice accretions. The current version, ICEG213 (v2.0), was designed to automatically perform four primary functions: (1) generate a grid-ready surface definition based on the geometrical characteristics of the iced airfoil surface, (2) generate high-quality structured and generalized grids starting from a defined surface definition, (3) generate the input and restart files needed to run the structured grid CFD solver NPARC or the generalized grid CFD solver HYBFL2D, and (4) using the flow solutions, generate solution-adaptive grids. ICEG2D (v2.0) can be operated in either a batch mode using a script file or in an interactive mode by entering directives from a command line within a Unix shell. This report summarizes activities completed in the first two years of a three-year research and development program to address automation issues related to CFD simulations for airfoils with ice accretions. As well as describing the technology employed in the software, this document serves as a users manual providing installation and operating instructions. An evaluation of the software is also presented.

Thompson David S.; Soni, Bharat K.



Cloning, expression and characterization of mugwort pollen allergen Art v 2, a pathogenesis-related protein from family group 1.  


Mugwort (Artemisia vulgaris) belongs to the Compositae family, and is one of the main causes of allergy in late summer and autumn. The aim of the study was to characterize the allergen Art v 2 from mugwort pollen. Skin prick tests, performed in 19 patients allergic to mugwort and 10 control patients, showed an Art v 2 sensitization prevalence of 58%, whereas none false-positives were detected among control patients. Art v 2 was purified by standard chromatography and binding to Concanavalin A column and had an apparent molecular mass of 33 and 20 kDa, calculated by gel permeation and SDS-PAGE under denaturing conditions, respectively, showing that the allergen is composed of two identical subunits. Art v 2-encoding cDNA was amplified by PCR using degenerate primers based on reported partial amino acid sequences. Cloned cDNA encoding Art v 2 contains 140 bp that codify for a polypeptide of 15.8 kDa, with a predicted pI value of 5.2, and one potential N-glycosylation site. Protein homology search demonstrated that Art v 2 share 55-42% identical residues with pathogenesis-related protein PR-1 of tomato, potato, rape, wheat and rice. Homology was also found to Ves v 5 (41% identical residues). Bacterial-expressed recombinant Art v 2 was recognized only by 21% of mugwort-allergic patients. In conclusion, Art v 2 from mugwort is the first weed pollen allergen that belongs to the pathogenesis-related protein PR-1 and its recombinant form could help molecular diagnosis of mugwort associated allergy. PMID:17521730

Arilla, M C; Ibarrola, I; Puente, Y; Daza, J C; Martínez, A; Asturias, J A



Platinum-group element distribution in base-metal sulfides of the UG2 chromitite, Bushveld Complex, South Africa—a reconnaissance study  

NASA Astrophysics Data System (ADS)

Two drill cores of the UG2 chromitite from the eastern and western Bushveld Complex were studied by whole-rock analysis, ore microscopy, SEM/Mineral Liberation Analysis (MLA), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. The top and base of the UG2 main seam have the highest bulk-rock Pd and Pt concentrations. Sulfides mostly occur as aggregates of pentlandite, chalcopyrite, and rare pyrrhotite and pyrite or as individual grains associated mostly with chromite grains. In situ LA-ICP-MS analyses reveal that pentlandite carries distinctly elevated platinum-group element (PGE) contents. In contrast, pyrrhotite and chalcopyrite contain very low PGE concentrations. Pentlandite shows average maximum values of 350-1,000 ppm Pd, 200 ppm Rh, 130-175 ppm Ru, 20 ppm Os, and 150 ppm Ir, and is the principal host of Pd and Rh in the studied ores of the UG2. Mass balance calculations were conducted for samples representing the UG2 main seam of the drill core DT46, eastern Bushveld. Pentlandite consistently hosts elevated contents of the whole-rock Pd (up to 55 %) and Rh (up to 46 %), and erratic contents of Os (up to 50 %), Ir (2 to 17 %), and Ru (1-39 %). Platinum-group mineral (PGM) investigations support these mass balance results; most of the PGM are Pt-dominant such as braggite/cooperite and Pt-Fe alloys or laurite (carrying elevated concentrations of Os and Ir). Palladium and Rh-bearing PGM are rare. Both PGE concentrations and their distribution in base-metal sulfides (BMS) in the UG2 largely resemble that of the Merensky Reef, as most of the Pd and Rh are incorporated in pentlandite, whereas pyrrhotite, chalcopyrite, and pyrite are almost devoid of PGE.

Osbahr, Inga; Oberthür, Thomas; Klemd, Reiner; Josties, Anja



The mineralogy and mineral associations of platinum group elements and gold in the Platreef at Zwartfontein, Akanani Project, Northern Bushveld Complex, South Africa  

NASA Astrophysics Data System (ADS)

The mineralogy of the platinum-group elements (PGE), and gold, in the Platreef of the Bushveld Complex, was investigated using an FEI Mineral Liberation Analyser. Polished sections were prepared from 171 samples collected from two boreholes, for the in-situ examination of platinum group minerals (PGM). PGM and gold minerals encountered include maslovite (PtBiTe, 32 area% of total PGM), kotulskite (Pd(BiTe), 17 %), isoferroplatinum (Pt3Fe, 15 %), sperrylite (PtAs2, 11 %), cooperite (PtS, 5 %), moncheite (PtTe2; 5 %), electrum (AuAg; 5 %), michenerite (PdBiTe; 3 %), Pd alloys (Pd, Sb, Sn; 3 %), hollingworthite ((Rh,Pt)AsS; 2 %), as well as minor (all <1 area% of total PGM) merenskyite (PdBiTe2), laurite (RuS2), rustenburgite (Pt0.4Pd0.4Sn0.2), froodite (PdBi2), atokite (Pd0.5Pt0.3Sn0.2), stumpflite (PtSb), plumbopalladinite (Pd3Pb2), and zvyagintsevite (Pd3Pb). An observed association of all PGM with base metal sulfides (BMS), and a pronounced association of PGE tellurides, arsenides and Pd&Pt alloys with secondary silicates, is consistent with the remobilisation and recrystallisation of some of the PGM's during hydrothermal alteration and serpentinisation subsequent to their initial (primary) crystallisation from BMS (e.g. Godel et al. J Petrol 48:1569-1604, 2007; Hutchinson and McDonald Appl Earth Sci (Trans Inst Min Metall B) 114:B208-224, 2008).

van der Merwe, Frits; Viljoen, Fanus; Knoper, Mike



GEANT4 Simulation of Hadronic Interactions at 8-GeV/C to 10-GeV/C: Response to the HARP-CDP Group  

SciTech Connect

The results of the HARP-CDP group on the comparison of GEANT4 Monte Carlo predictions versus experimental data are discussed. It is shown that the problems observed by the group are caused by an incorrect implementation of old features at the programming level, and by a lack of the nucleon Fermi motion in the simulation of quasielastic scattering. These drawbacks are not due to the physical models used. They do not manifest themselves in the most important applications of the GEANT4 toolkit.

Uzhinsky, V.; /Dubna, JINR /CERN; Apostolakis, J.; Folger, G.; /CERN; Ivanchenko, V.N.; /CERN /Moscow State U.; Kossov, M.V.; /CERN /Moscow, ITEP; Wright, D.H.; /SLAC



Sulfide-associated mineral assemblages in the Bushveld Complex, South Africa: platinum-group element enrichment by vapor refining by chloride-carbonate fluids  

NASA Astrophysics Data System (ADS)

The petrology of base metal sulfides and associated accessory minerals in rocks away from economically significant ore zones such as the Merensky Reef of the Bushveld Complex has previously received only scant attention, yet this information is critical in the evaluation of models for the formation of Bushveld-type platinum-group element (PGE) deposits. Trace sulfide minerals, primarily pyrite, pyrrhotite, pentlandite, and chalcopyrite are generally less than 100 microns in size, and occur as disseminated interstitial individual grains, as polyphase assemblages, and less commonly as inclusions in pyroxene, plagioclase, and olivine. Pyrite after pyrrhotite is commonly associated with low temperature greenschist alteration haloes around sulfide grains. Pyrrhotite hosted by Cr- and Ti-poor magnetite (Fe3O4) occurs in several samples from the Marginal to Lower Critical Zones below the platiniferous Merensky Reef. These grains occur with calcite that is in textural equilibrium with the igneous silicate minerals, occur with Cl-rich apatite, and are interpreted as resulting from high temperature sulfur loss during degassing of interstitial liquid. A quantitative model demonstrates how many of the first-order features of the Bushveld ore metal distribution could have developed by vapor refining of the crystal pile by chloride-carbonate-rich fluids during which sulfur and sulfide are continuously recycled, with sulfur moving from the interior of the crystal pile to the top during vapor degassing.

Kanitpanyacharoen, W.; Boudreau, A. E.



Determination of the platinum - Group elements (PGE) and gold (Au) in manganese nodule reference samples by nickel sulfide fire-assay and Te coprecipitation with ICP-MS  

USGS Publications Warehouse

Platinum group elements (PGE) and Au data in polymetallic oceanic ferromanganese nodule reference samples and crust samples obtained by inductively coupled plasma mass spectrometry (ICP-MS), after separation and pre-concentration by nickel sulfide fire-assay and Te coprecipitation, are presented. By optimizing several critical parameters such as flux composition, matrix matching calibration, etc., best experimental conditions were established to develop a method suitable for routine analysis of manganese nodule samples for PGE and Au. Calibrations were performed using international PGE reference materials, WMG-1 and WMS-1. This improved procedure offers extremely low detection limits in the range of 0.004 to 0.016 ng/g. The results obtained in this study for the reference materials compare well with previously published data wherever available. New PGE data arc also provided on some international manganese nodule reference materials. The analytical methodology described here can be used for the routine analysis of manganese nodule and crust samples in marine geochemical studies.

Balaram, V.; Mathur, R.; Banakar, V.K.; Hein, J.R.; Rao, C.R.M.; Gnaneswara, Rao T.; Dasaram, B.



Presentations and Structural Properties of Self-similar Groups and Groups without Free Sub-semigroups  

E-print Network

(X ) let supp(g) denote the set of vertices on which g acts non-trivially, i.e., its support. Given a subgroup G of Aut(X ) and a vertex v 2 X , let RistG(v) = fg 2 G j supp(g) vX g be the subgroup consisting of elements of G which act trivially outside... index in G (resp. are non-trivial). We remark that such groups are sometimes called geometric branch groups. There is a more general notion of an algebraic branch group (see [Gri00]). De nition 2.10 has two immediate algebraic consequences, rstly...

Benli, Mustafa G




E-print Network

of enzyme(s) with phospholipase A2 (PLA2) activity from human neutrophils. We show that circulating human neutrophils express groups V and X sPLA2 (GV and GX sPLA2) mRNA and contain GV and GX sPLA2 proteins, whereas GIB, GIIA, GIID, GIIE, GIIF, GIII, and GXII sPLA2s are undetectable. GV sPLA2 is a component of both

Gelb, Michael


Calculations on various total cross-sections of electron impact on group VA - atoms-threshold to 2000 eV  

NASA Astrophysics Data System (ADS)

In this paper we have calculated various total cross-sections of Nitrogen, Phosphorus, Arsenic, Antimony and Bismuth (Group VA-atoms) in the energy range of 15 to 2000 eV. Spherical Complex potential formalism is used to derive total as well as inelastic cross-sections. We have developed CSP-ic method by which we can extract ionization cress-section from the inelastic cross-section. Our results are compared with available theoretical and experimental data.

Joshipura, K. N.; Gangopadhyay, Sumona; Kothari, Harshit N.; Shelat, Foram A.



[Results of treatment of children with acute lymphatic leukemia (ALL) according to the ALL V protocol of the Netherlands Working Group on Leukemia in Children].  


The Dutch Childhood Leukemia Study Group performed a phase III study (Study ALL V) to evaluate the effectiveness of addition of rubidomycin to induction treatment with vincristine, prednisone and L-asparaginase in children (0-15 years) with standard risk acute lymphoblastic leukemia: WBC less than 50.10(9)/l, absence of mediastinal mass and/or cerebromeningeal leukemia. Furthermore, the influence of some initial patient- en disease-characteristics on the outcome was analysed. Between May 1979 and December 1982 240 patients entered into the study and were randomized into 2 groups: group A (n = 122) received induction treatment with vincristine, prednisone and L-asparaginase; group B (n = 118) received induction treatment with vincristine, prednisone, L-asparaginase and rubidomycin. All patients received cranial irradiation (doses adjusted to age) and intrathecal methotrexate, followed by maintenance treatment with 6-mercaptopurine and methotrexate for 5 weeks, alternated with vincristine and prednisone for 2 weeks, up to 24 months. Complete remission rate was 94% in both groups. Event-free survival at 5 years after diagnosis was higher in group B (62% +/- 4.6%) than in group A (54.2% +/- 4.6%) but the difference was not significant. A higher initial WBC, age greater than or equal to 10 years and a positive acid phosphatase reaction of the leukemic cells were unfavorable prognostic factors (p less than 0.01). Sex, FAB-morphology, immunophenotype and place of treatment (center or general hospital) were not significant factors. PMID:3287685

van der Does-van den Berg, A; van Wering, E R; Suciu, S; Solbu, G; Rammeloo, J A; de Koning, J; van Zanen, G E



78 FR 12873 - United States v. Apple, Inc., Hachette Book Group, Inc., Harpercollins Publishers L.L.C...  

Federal Register 2010, 2011, 2012, 2013

...principal place of business at G[auml]nsheidestra...Stuttgart 70184, Germany. 16. Penguin Group...way that they were doing business,'' i.e., with...principal place of business in Stuttgart, Germany...



77 FR 24518 - United States v. Apple, Inc., Hachette Book Group, Inc., HarperCollins Publishers L.L.C...  

Federal Register 2010, 2011, 2012, 2013

...principal place of business at G[auml]nsheidestra...Stuttgart 70184, Germany. 16. Penguin Group...way that they were doing business,'' i.e., with...principal place of business in Stuttgart, Germany, their...



77 FR 77094 - United States v. Apple, Inc., Hachette Book Group, Inc., HarperCollins Publishers L.L.C...  

Federal Register 2010, 2011, 2012, 2013

...principal place of business at G[auml]nsheidestra...Stuttgart 70184, Germany. 16. Penguin Group...way that they were doing business,'' i.e., with...principal place of business in Stuttgart, Germany, their...



Blockade of glutamate transporters leads to potentiation of NMDA receptor current in layer V pyramidal neurons of the rat prefrontal cortex via group II metabotropic glutamate receptor activation.  


Membrane currents of layer V pyramidal cells in slices of the rat prefrontal cortex (PFC) were recorded with the patch-clamp technique. In an Mg2+-free superfusion medium l-trans-pyrrolidine-2,4-dicarboxylic acid (PDC), a preferential blocker of astrocytic glutamate transporters, caused inward current due to the activation of NMDA receptors. The blockade of conducted action potentials by tetrodotoxin did not interfere with this effect. ATP was inactive when given alone and potentiated the NMDA-induced current in an Mg2+-containing but not Mg2+-free superfusion medium. Agonists of group I ((S)-3,5-dihydroxyphenylglycine; DHPG) and II ((1R,4R,5S,6R)-4-amino-2-oxabicyclo[3.1.0]hexane-4,6-dicarboxylic acid; LY 379268) metabotropic glutamate receptors (mGluRs) also potentiated responses to NMDA, whereas the group III mGluR agonist L-(+)-2-amino-4-phosphonobutyric acid (L-AP4) did not affect them. In contrast to ATP, PDC evoked inward current in the absence but not in the presence of external Mg2+, when given alone, and facilitated the NMDA effect Mg2+-independently. The PDC-induced facilitation of NMDA responses was blocked by group II ((2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid; LY 341495), but not group I ((RS)-1-aminoindan-1,5-dicarboxylic acid; AIDA) or III (alpha-methyl-3-methyl-4-phosphonophenylglycine; UBP 1112) mGluR antagonists. In conclusion, the blockade of astrocytic glutamate uptake by PDC may lead to a stimulation of group II mGluRs, while the triggering of exocytotic glutamate release from astrocytes by ATP may cause activation of group I mGluRs, both situated postsynaptically at layer V PFC pyramidal cells. Either group of mGluRs may interact with NMDA receptors in a positive manner. PMID:18680754

Oliveira, Joao F; Krügel, Ute; Köles, Laszlo; Illes, Peter; Wirkner, Kerstin



Differences in the activities of eight enzymes from ten soil fungi and their possible influences on the surface structure, functional groups, and element composition of soil colloids.  


How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, ?-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3-4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C?=?O, COO- decreased by 11-60%, while P?=?O, C-O stretching, O-H bending and Si-O-Si stretching increased 9-22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11-49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance. PMID:25398013

Wang, Wenjie; Li, Yanhong; Wang, Huimei; Zu, Yuangang



Differences in the Activities of Eight Enzymes from Ten Soil Fungi and Their Possible Influences on the Surface Structure, Functional Groups, and Element Composition of Soil Colloids  

PubMed Central

How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, ?-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3–4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C?=?O, COO- decreased by 11–60%, while P?=?O, C-O stretching, O-H bending and Si-O-Si stretching increased 9–22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11–49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance. PMID:25398013

Wang, Wenjie; Li, Yanhong; Wang, Huimei; Zu, Yuangang



Selenium and sulfur concentrations in the Bushveld Complex of South Africa and implications for formation of the platinum-group element deposits  

Microsoft Academic Search

We have determined the S, Se, Cu and La contents through a complete stratigraphic section of the Bushveld Complex. The principle aim was to determine which phases controlled these elements. S, Se and Cu show positive correlations, but these elements do not correlate with La. In most cases, the concentration of S, Se and Cu in rocks containing greater than

Sarah-Jane Barnes; Dany Savard; L. Paul Bédard; Wolfgang D. Maier



Multipole Matrix Elements v for H-Like Atoms and Their Applications (as ? = 1, n ? 4, Enl < 0 ? E ? 1)  

NASA Astrophysics Data System (ADS)

This article deals with the connection between multipole matrix elements ? and ? for H-like atoms, where ? is the so-called "auxiliary" parameter of Heun's differential equation and ˜ {Z}=Z/? is the "effective" nuclear charge, and new properties of Appell's function F2(x,y) to the vicinity of the singular point (1, 1) and in addition, here, first V. A. Fock's idea for the continuous spectrum is taken into consideration. Such an approach allows us to get the explicit expressions for squares of the dipole moments and the certain physical characteristics in atomic physics and also their exact numerical values, e.g., the average oscillator strengths bar {f}(nl,El') and the line intensities J(nl, El'), etc., as n ? 4, l'= l ± 1 and 0 ? E ? 1 (see Tables 1-3). Besides, diagrams of certain radial functions for the discrete-continuous transitions are given here.

Tarasov, V. F.


Bactericidal Properties of Human and Murine Groups I, II, V, X, and XII Secreted Phospholipases A2*  

E-print Network

IIA secreted phospholipase A2 (sPLA2) is known to display potent Gram-positive bactericidal ac- tivity, and Escherichia coli. The rank order potency among human sPLA2s against Gram-positive bacteria is group IIA > X is the dominant factor in dictating bactericidal potency; 2) basic residues on the putative membrane binding

Gelb, Michael


Single-experiment simultaneous-measurement of elemental mass-attenuation coefficients of hydrogen, carbon and oxygen for 0.123–1.33 MeV gamma rays  

Microsoft Academic Search

As it is inconvenient to use elements like hydrogen, carbon and oxygen in pure forms for measurement of their gamma mass-attenuation coefficients, the measurements are to be done indirectly, by using compounds of the elements or a mixture of them. We give here a simple method of measuring the total mass-attenuation coefficients ?\\/? of the elements in a compound simultaneously

M. T. Teli; R. Nathuram; C. S. Mahajan



Radiative Lifetimes of V I and V II  

NASA Astrophysics Data System (ADS)

New radiative lifetimes are reported for 168 levels of V I ranging in energy from 18086 cm–1 to 47702 cm–1, and for 31 levels of V II ranging in energy from 34593 cm–1 to 47420 cm–1. These lifetimes are measured using time-resolved laser-induced fluorescence on a slow atomic/ionic beam as part of an ongoing study of the radiative properties of the iron group elements. All but two of the V II lifetimes have been measured before using modern laser-based methods, but a large fraction of the V I lifetimes are reported here for the first time. Comparison to earlier measurements is discussed. These new lifetimes are, for the most part, accurate to ±5%. They will be combined with branching fraction measurements to produce a large set of transition probabilities for V I and V II which are needed by the astrophysics community for stellar abundance determinations.

Den Hartog, E. A.; Lawler, J. E.; Wood, M. P.



Automata groups  

E-print Network

of Mihailova normal form concerns only free groups, it can be useful for any group G, and we will use the following natural 11 definition: Definition II.12. Let G be a group with non-trivial generators{a1,...,an}, and H be a subgroup of the direct product G... to show that the defining relators in the group ?? are mapped to the trivial element of the group ???. In all three cases we have ??(a)2 = ((1,1)?)2 = (1,1), ??(x)2 = (1,?x2) = (1,1), ??(y)2 = (?a2,?y2) = (1,1), ??(z)2 = (?a2,?z2) = (1,1), ??(x...

Muntyan, Yevgen



Group V secretory phospholipase A2 is involved in macrophage activation and is sufficient for macrophage effector functions in allergic pulmonary inflammation  

PubMed Central

We reported that Pla2g5-null mice lacking group V secretory phospholipase A2 (gV-sPLA2) showed reduced eosinophilic pulmonary inflammation and Th2 cytokine generation when challenged with an extract (Df) from house dust mite Dermatophagoides farinae, compared to wild-type (WT) controls. Adoptive transfer studies suggested that gV-sPLA2 in dendritic cells (DCs) was necessary for sensitization of Pla2g5-null mice, but was not sufficient to induce the effector phase of pulmonary inflammation. Here, we demonstrate that gV-sPLA2 is inducibly expressed in mouse and human macrophages (M? activated by IL-4, and is required for the acquisition of M? effector functions that facilitate the effector phase of pulmonary inflammation. We demonstrate that gV-sPLA2 expression in M? is sufficient for the development of pulmonary inflammation, even when inflammation is induced by intrapulmonary administration of IL-4. The concentrations of CCL22/CCL17 and effector T-cell recruitment are severely impaired in Pla2g5-null mice. Intratracheal transfers of enriched CD68+ cells isolated from the lungs of Df-challenged WT donor mice induce eosinophilia, chemokine production, and recruitment of T-cells into the lungs of Pla2g5-null recipients previously sensitized by WT Df-loaded DCs. Our studies identified a unique function of gV-sPLA2 in activation of M? and in their capacity to recruit T-cells to amplify the effector phase of pulmonary inflammation. PMID:23650617

Ohta, Shin; Imamura, Mitsuru; Xing, Wei; Boyce, Joshua A.; Balestrieri, Barbara



A protective surface protein from type V group B streptococci shares N-terminal sequence homology with the alpha C protein.  

PubMed Central

Infection by group B streptococci (GBS) is an important cause of bacterial disease in neonates, pregnant women, and nonpregnant adults. Historically, serotypes Ia, Ib, II, and III have been most prevalent among disease cases; recently, type V strains have emerged as important strains in the United States and elsewhere. In addition to type-specific capsular polysaccharides, many GBS strains possess surface proteins which demonstrate a laddering pattern on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and resistance to trypsin digestion. These include the alpha C protein, the R proteins, and protein Rib. Some of these proteins elicit protective antibodies in animals. We demonstrate a trypsin-resistant laddering protein purified from a type V GBS strain by mutanolysin extraction and column chromatography. This protein contains a major 90-kDa band and a series of smaller bands spaced approximately 10 kDa apart on SDS-PAGE. Cross-reactivity of the type V protein with the alpha C protein and with R1 was demonstrated on Western blot (immunoblot). N-terminal sequence analysis of the protein revealed residue identity with 17 of 18 residues at corresponding positions on the alpha protein. Western blot of SDS extracts of 41 clinical type V isolates with rabbit antiserum to the protein demonstrated a homologous protein in 25 isolates (61%); two additional strains exhibited a heterologous pattern which was also demonstrated with 4G8, a monoclonal antibody directed to the alpha C protein repeat region. Rabbit antiserum raised to the type V protein conferred protection in neonatal mice against a type V strain bearing a homologous protein. These data support the hypothesis that there exists a family of trypsin-resistant, laddering GBS surface proteins which may play a role in immunity to GBS infection. PMID:8926097

Lachenauer, C S; Madoff, L C



Selenium and sulfur concentrations in the Bushveld Complex of South Africa and implications for formation of the platinum-group element deposits  

Microsoft Academic Search

We have determined the S, Se, Cu and La contents through a complete stratigraphic section of the Bushveld Complex. The principle\\u000a aim was to determine which phases controlled these elements. S, Se and Cu show positive correlations, but these elements do\\u000a not correlate with La. In most cases, the concentration of S, Se and Cu in rocks containing greater than

Sarah-Jane Barnes; Dany Savard; L. Paul Bédard; Wolfgang D. Maier



A new mixed group 5 metal selenide, Nb1.41V0.59Se9  

PubMed Central

The new mixed-metallic phase, niobium vanadium nona­selenide, (Nb2-xVx)Se9 (0.18? x ? 0.59) is isostructural with monoclinic V2Se9. The structure is composed of chains of bicapped trigonal–prismatic [MSe8] units. The metal (M) site is occupied by statistically disordered Nb [0.706?(5)] and V [0.294?(5)] atoms. Two trigonal prisms are linked by sharing a recta­ngular face composed of two Se2 2? pairs. Through three edging and capping Se atoms, the chains are extended along [101]. The chain shows alternating short [2.8847?(7)?Å] and long [3.7159?(7)?Å] M—M distances. The structure shows a wide range of Se—Se inter­actions. In addition to the Se2 2? pairs of the recta­ngular face, an inter­mediate Se?Se separation [2.6584?(5)?Å] is found. The amount of each metal can vary, [(Nb2-xVx)Se9, 0.18 ? x ?m 0.59] and they seem to form a random substitutional solid solution. The M—M distances increase gradually by increasing the amount of Nb atoms. The classical charge-balance of the compound can be described as [M 4+]2[Se2 2?]2[Se5 4?]. PMID:22064790

Lee, Eunsil; Yun, Hoseop



An ab initio study of the energetics for interfaces between group V transition metal Nitrides and bcc iron  

NASA Astrophysics Data System (ADS)

An ab initio study was carried out on interface energies, misfit strain energies and electron structures at coherent interfaces between bcc Fe and Nitrides (XNs) (NaCl structure, X = V, Nb, Ta). The interface energies at relaxed interfaces Fe/VN, Fe/NbN and Fe/TaN were -0.051 J m-2, -0.226 J m-2 and -0.643 J m-2, respectively. The influence of bond energy was estimated using the discrete lattice plane/nearest neighbour broken bond model. It was found that the dependence of interface energy on the type of nitride was closely related to changes of the bond energies between Fe, X and N atoms before and after formation of the interfaces Fe/XN. The misfit strain energies in Fe/VN, Fe/NbN and Fe/TaN systems were -0.052, 0.178 and 0.005 eV per 16 atoms (Fe 8 atoms and XN 8 atoms). The misfit strain energy became larger when the difference in lattice parameters between the bulk Fe and the bulk XNs increased.

Jung, Woo-Sang; Chung, Soon-Hyo; Ha, Heon-Phil; Byun, Ji-Young



Platinum Group Elements, 187OS/188OS and 87SR/86SR Isotope Systematics in Depleted Fluid-Modified Mariana Fore-Arc Peridotites  

NASA Astrophysics Data System (ADS)

The serpentine mud volcanoes of the Izu-Bonin-Mariana (IBM) fore-arc, collected during Ocean Drilling Program Leg 195 [1], contain hard-rock clasts of serpentine sampled from close to the décollement, which separates the down-going Pacific slab from the overlying mantle wedge. These clasts preserve evidence for melt depletion (>25 % melt extraction in many instances) in a sub-arc environment, and extensive (40 - 100%) serpentinization due to subsequent fluid / peridotite interaction, e.g. [2]. Platinum-group element (PGE) abundances are not consistent with melt-depletion alone [3]. Fractionation between I-PGE (Os, Ir, Ru) has resulted in groups of IBM serpentinites with either a high chondrite-normalized Os/Ir ratio (OsN/IrN) or a low OsN/IrN ratio. Similarly, fractionation of P-PGE (Pt, Pd) is marked, and distinguishes the IBM serpentinites from worldwide abyssal peridotites. Interaction with high-pH fluids [4] may have partially oxidized mantle sulphide, the major primary host for PGE in these rocks, leading to partial breakdown to sulphate and the selective redistribution of certain PGE (Os, Ru, Pt), a feature normally associated with sub-aerial weathering [5], but which likely prevails in other oxidizing environments. In particular, the Re-Os systematics of the high (OsN/IrN) IBM serpentinites have been disturbed by the addition of Os. Unlike peridotite xenoliths associated with magmatic regions of subduction zones where subduction-related Os-addition is unequivocally radiogenic and derived from crustal material [6][7], where Os has been added to the IBM serpentinites it is unradiogenic and was most likely derived from within the oceanic mantle. IBM serpentinites therefore preserve osmium isotope ratios that are exclusively sub-chondritic (187Os/188Os ? 0.127), as previously reported [8]. These serpentinized peridotites were produced by at least a three-step process: melt depletion, serpentinization, and the mobilization of Os, Ru and Pt to produce low OsN/IrN "donor" and high OsN/IrN "recipient" serpentinites. The distinct chondrite normalized PGE patterns of the low OsN/IrN serpentinites are remarkably similar to those of back-arc basin basalts (BABB) from sites 291, 292, 444A, 450 drilled in the Philippine Sea Plate (PSP) during DSDP Legs 31, 58 and 59 [9]. [1] Fryer, et al. (1992) Proc. ODP Sci. Results 125, Fryer, P., Pearce, J. A., Stokking, L. B., et al., 373-385, Ocean Drilling Program, College Station TX, USA. [2] Savov et al. (2005) Geochem. Geophys. Geosyst. 6, Q04J15, doi:10.1029/2004GC000777 [3] Handler, & Bennett (1999) Geochim. Cosmochim. Acta 63, 3597-3618 [4] Mottl, M.J. (1992) Proc. ODP Sci. Results, 125, Fryer, P., Pearce, J. A., Stokking, L. B., et al., 373-385, Ocean Drilling Program, College Station TX, USA. [5] Lorand, et al. (2003) Geochim. Cosmochim. Acta 67, 4137-4151. [6] Brandon et al. (1999) Chem. Geol. 160, 387-407. [7] Widom et al. (2003) Chem. Geol. 196, 283- 306. [8] Parkinson et al. (1999) Science 281, 211-312 [9] Dale et al. (2008) Chem. Geol. 248, 213-238.

Harvey, J.; Savov, I. P.; Shirey, S. B.; Horan, M. F.; Mock, T. D.



Multi-elemental characterization of tunnel and road dusts in Houston, Texas using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry: evidence for the release of platinum group and anthropogenic metals from motor vehicles.  


Platinum group elements (PGEs) including Rh, Pd, and Pt are important tracers for vehicular emissions, though their measurement is often challenging and difficult to replicate in environmental campaigns. These challenges arise from sample preparation steps required for PGE quantitation, which often cause severe isobaric interferences and spectral overlaps from polyatomic species of other anthropogenically emitted metals. Consequently, most previous road dust studies have either only quantified PGEs or included a small number of anthropogenic elements. Therefore a novel analytical method was developed to simultaneously measure PGEs, lanthanoids, transition and main group elements to comprehensively characterize the elemental composition of urban road and tunnel dusts. Dust samples collected from the vicinity of high-traffic roadways and a busy underwater tunnel restricted to single-axle (predominantly gasoline-driven) vehicles in Houston, TX were analyzed for 45 metals with the newly developed method using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry (DRC-q-ICP-MS). Average Rh, Pd and Pt concentrations were 152±52, 770±208 and 529±130 ng g(-1) respectively in tunnel dusts while they varied between 6 and 8 ng g(-1), 10 and 88 ng g(-1) and 35 and 131 ng g(-1) in surface road dusts. Elemental ratios and enrichment factors demonstrated that PGEs in dusts originated from autocatalyst attrition/abrasion. Strong evidence is also presented for mobile source emissions of Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, W and Pb. However, all other elements including rare earths most likely arose from weathering, erosion and resuspension of crustal material. These are the first such detailed measurements in Houston, the largest city in TX and fourth largest in the United States. We posit that such investigations will assist in better understanding PGE concentrations in urban environments while providing elemental data necessary to better understand anthropogenic influences on their biogeochemical cycling. PMID:22713911

Spada, Nicholas; Bozlaker, Ayse; Chellam, Shankararaman



Proton inelastic mean free path in a group of bioorganic compounds and water in 0.05-10 MeV range - Including higher-order corrections  

NASA Astrophysics Data System (ADS)

The systematic calculations of the inelastic mean free paths (MFP) of 0.05-10 MeV protons in a group of eleven important bioorganic compounds, i.e. DNA, five bases, three fatty acids, cellulose and ?-carotene, have been performed. The expressions for the calculations are derived from the Ashley's optical-data model and from the higher-order correction terms in stopping power calculations. Especially, the Bloch correction for the inelastic MFP is proposed empirically in this work. The inelastic MFPs for energetic protons in water are also evaluated and compared with other theoretical calculations. The proton inelastic MFPs for these 11 bioorganic compounds in the energy range from 0.05 to 10 MeV are presented here for the first time, and might be useful for studies of various radiation effects in these materials.

Tan, Zhenyu; Xia, Yueyuan; Zhao, Mingwen; Liu, Xiangdong



Endothelial protein C receptor-associated invasiveness of rheumatoid synovial fibroblasts is likely driven by group V secretory phospholipase A2  

PubMed Central

Introduction Rheumatoid synovial fibroblasts (RASFs) mediate joint inflammation and destruction in rheumatoid arthritis (RA). Endothelial protein C receptor (EPCR) is a specific receptor for the natural anticoagulant activated protein C (APC). It mediates the cytoprotective properties of APC and is expressed in rheumatoid synovial tissue. A recent report shows that group V secretory phospholipase A2 (sPLA2V) prevents APC from binding to EPCR in endothelium and inhibits EPCR/APC function. The aim of this study was to investigate the expression and function of EPCR on RASFs. Methods Human synovial fibroblasts (SFs) were isolated from RA or osteoarthritis (OA) synovial tissues and treated with control, EPCR, or sPLA2V small interfering RNA (siRNA); recombinant human APC, tumor necrosis factor-alpha (TNF-?), or sPLA2V. RASF viability and migration/invasion were measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and collagen gel migration/invasion assays, respectively, and cartilage degradation by 1,9-dimethylmethylene blue (DMMB) assay in the presence of human OA articular cartilage explants. The expression or activation of cytokines, EPCR, cadherin-11, mitogen-activated protein (MAP) kinases, and nuclear factor-kappa-B (NF-?B) or both were detected by enzyme-linked immunosorbent assay, Western blotting, or immunostaining. Results EPCR was expressed by both OASFs and RASFs but was markedly increased in RASFs. When EPCR was suppressed by siRNA or blocking antibody cell viability, cell invasion and cartilage degradation were reduced by more than 30%. Inflammatory mediators interleukin-1-beta (IL-1?), cadherin-11, and NF-?B were significantly reduced by EPCR suppression under control or TNF-?-stimulated conditions. The expression or activation (or both) of MAP kinases ERK, p38, and JNK were also markedly decreased in cells transfected with EPCR siRNA. Further analysis revealed that sPLA2V co-localized with EPCR on RASFs. Suppression of sPLA2V reduced cell viability and cartilage degradation and increased APC binding to RASFs. Conversely, recombinant sPLA2V increased cartilage degradation, blocked APC binding to RASFs, and could not rescue the effects induced by EPCR suppression. Conclusions Our results demonstrate that EPCR is overexpressed by RASFs and mediates the aggressive behavior of RASFs. This function of EPCR is contrary to its cytoprotective role in other settings and is likely driven by sPLA2V. PMID:24495480



Theoretical investigation into optical and electronic properties of oligothiophene derivatives with phenyl ring as core or end-capped group in linear and V-shape  

Microsoft Academic Search

A series of thiophene-based oligomers has been designed to explore their optical, electronic, and charge transport properties\\u000a for charge transport materials. These oligomers consist of oligothiophene, oligo(thienylenevinylene), and m- or p-phenyl as the core in two shapes (linear shape and V-shape). Phenyl ring as the end-capped group is also investigated in\\u000a the linear shape. The DFT-PBE0\\/6-31G(d,p) and the TD-PBE0\\/6-31+G(d,p) calculated

Shanshan Tang; Jingping Zhang



Electronic Structures of Several Intermetallic Semiconductors for Expected Thermoelectric Applications: Alkaline-earth metal Pnictides, Iron group element Gallides and Indiumides, and Ir3Si5  

Microsoft Academic Search

We present the results of electronic structure calculations of Mg 3Pn2 (Pn: As, Sb, Bi), TA3 (T: Fe, Ru, Os, A: Ga, In) and Ir3Si5 obtained by a first-principle pseudopotential method. The calculated band gaps are 0.41 eV for Mg3Sb2, 0.5 eV for FeGa3, and 1.14 eV for Ir3Si5. These are narrower than the observed values in the case of

Y. Imai; A. Watanabe; T. Tsuchiya; T. Kumagai



A trace element study of siderite–jasper banded iron formation in the 3.45 Ga Warrawoona Group, Pilbara Craton—Formation from hydrothermal fluids and shallow seawater  

Microsoft Academic Search

Shale-normalised rare earth element and yttrium (REE+Y) patterns for siderite–jasper couples in a banded iron formation of the 3.45Ga Panorama Formation, Warrawoona Group, eastern Pilbara Craton, display distinct positive Y and Eu anomalies and weak positive La and Gd anomalies, combined with depleted light REE relative to middle and heavy REE. Ambient seawater and hydrothermal fluids are identified as major

Robert Bolhar; Martin J. Van Kranendonk; Balz S. Kamber



A distinct group of hepacivirus/pestivirus-like internal ribosomal entry sites in members of diverse picornavirus genera: evidence for modular exchange of functional noncoding RNA elements by recombination.  


The 5' untranslated regions (UTRs) of the RNA genomes of Flaviviridae of the Hepacivirus and Pestivirus genera contain internal ribosomal entry sites (IRESs) that are unrelated to the two principal classes of IRESs of Picornaviridae. The mechanism of translation initiation on hepacivirus/pestivirus (HP) IRESs, which involves factor-independent binding to ribosomal 40S subunits, also differs fundamentally from initiation on these picornavirus IRESs. Ribosomal binding to HP IRESs requires conserved sequences that form a pseudoknot and the adjacent IIId and IIIe domains; analogous elements do not occur in the two principal groups of picornavirus IRESs. Here, comparative sequence analysis was used to identify a subset of picornaviruses from multiple genera that contain 5' UTR sequences with significant similarities to HP IRESs. They are avian encephalomyelitis virus, duck hepatitis virus 1, duck picornavirus, porcine teschovirus, porcine enterovirus 8, Seneca Valley virus, and simian picornavirus. Their 5' UTRs are predicted to form several structures, in some of which the peripheral elements differ from the corresponding HP IRES elements but in which the core pseudoknot, domain IIId, and domain IIIe elements are all closely related. These findings suggest that HP-like IRESs have been exchanged between unrelated virus families by recombination and support the hypothesis that RNA viruses consist of modular coding and noncoding elements that can exchange and evolve independently. PMID:17392358

Hellen, Christopher U T; de Breyne, Sylvain



A Distinct Group of Hepacivirus/Pestivirus-Like Internal Ribosomal Entry Sites in Members of Diverse Picornavirus Genera: Evidence for Modular Exchange of Functional Noncoding RNA Elements by Recombination? †  

PubMed Central

The 5? untranslated regions (UTRs) of the RNA genomes of Flaviviridae of the Hepacivirus and Pestivirus genera contain internal ribosomal entry sites (IRESs) that are unrelated to the two principal classes of IRESs of Picornaviridae. The mechanism of translation initiation on hepacivirus/pestivirus (HP) IRESs, which involves factor-independent binding to ribosomal 40S subunits, also differs fundamentally from initiation on these picornavirus IRESs. Ribosomal binding to HP IRESs requires conserved sequences that form a pseudoknot and the adjacent IIId and IIIe domains; analogous elements do not occur in the two principal groups of picornavirus IRESs. Here, comparative sequence analysis was used to identify a subset of picornaviruses from multiple genera that contain 5? UTR sequences with significant similarities to HP IRESs. They are avian encephalomyelitis virus, duck hepatitis virus 1, duck picornavirus, porcine teschovirus, porcine enterovirus 8, Seneca Valley virus, and simian picornavirus. Their 5? UTRs are predicted to form several structures, in some of which the peripheral elements differ from the corresponding HP IRES elements but in which the core pseudoknot, domain IIId, and domain IIIe elements are all closely related. These findings suggest that HP-like IRESs have been exchanged between unrelated virus families by recombination and support the hypothesis that RNA viruses consist of modular coding and noncoding elements that can exchange and evolve independently. PMID:17392358

Hellen, Christopher U. T.; de Breyne, Sylvain



Specific roles for Group V secretory PLA? in retinal iron-induced oxidative stress. Implications for age-related macular degeneration.  


Iron accumulation and oxidative stress are hallmarks of retinas from patients with age-related macular degeneration (AMD). We have previously demonstrated that iron-overloaded retinas are a good in vitro model for the study of retinal degeneration during iron-induced oxidative stress. In this model we have previously characterized the role of cytosolic phospholipase A2 (cPLA2) and calcium-independent isoform (iPLA2). The aim of the present study was to analyze the implications of Group V secretory PLA2 (sPLA2), another member of PLA2 family, in cyclooxygenase (COX)-2 and nuclear factor kappa B (NF-?B) regulation. We found that sPLA2 is localized in cytosolic fraction in an iron concentration-dependent manner. By immunoprecipitation (IP) assays we also demonstrated an increased association between Group V sPLA2 and COX-2 in retinas exposed to iron overload. However, COX-2 activity in IP assays was observed to decrease in spite of the increased protein levels observed. p65 (RelA) NF-?B levels were increased in nuclear fractions from retinas exposed to iron. In the presence of ATK (cPLA2 inhibitor) and YM 26734 (sPLA2 inhibitor), the nuclear localization of both p65 and p50 NF-?B subunits was restored to control levels in retinas exposed to iron-induced oxidative stress. Membrane repair mechanisms were also analyzed by studying the participation of acyltransferases in phospholipid remodeling during retinal oxidation stress. Acidic phospholipids, such as phosphatidylinositol (PI) and phosphatidylserine (PS), were observed to show an inhibited acylation profile in retinas exposed to iron while phosphatidylethanolamine (PE) showed the opposite. The use of PLA2 inhibitors demonstrated that PS is actively deacylated during iron-induced oxidative stress. Results from the present study suggest that Group V sPLA2 has multiple intracellular targets during iron-induced retinal degeneration and that the specific role of sPLA2 could be related to inflammatory responses by its participation in NF-?B and COX-2 regulation. PMID:23791636

Rodríguez Diez, G; Sánchez Campos, S; Giusto, N M; Salvador, G A



SCALE radiation shielding V and V package  

SciTech Connect

Verification and validation (V and V) are essential elements of software quality assurance (QA) for computer codes that are used for scientific calculations. The sponsors of the SCALE code system have required a QA plan and a V and V plan. For purposes of validating and verifying the SCALE shielding codes, a set of problems has been assembled and tested.

Emmett, M.B.; Bowman, S.M.; Broadhead, B.L.



Chemical Elements  

NSDL National Science Digital Library

To find quick facts on elements The Photographic Periodic Table of Elements-shows a photograhpic representation of most of the elements (remember some are invisible gases) The Element Song Click on the following links to find quick facts about the elements and peridoic table: Periodic Table of Elements: LANL - Originally this resource, the Periodic Table, was created by Robert Husted at Los Alamos National Laboratory during his time ...

Schultz, Ms.



Assessment of Degree of Applicability of Benchmarks for Gadolinium Using KENO V.a and the 238-Group SCALE Cross-Section Library  

SciTech Connect

A review of the degree of applicability of benchmarks containing gadolinium using the computer code KENO V.a and the gadolinium cross sections from the 238-group SCALE cross-section library has been performed for a system that contains {sup 239}Pu, H{sub 2}O, and Gd{sub 2}O{sub 3}. The system (practical problem) is a water-reflected spherical mixture that represents a dry-out condition on the bottom of a sludge receipt and adjustment tank around steam coils. Due to variability of the mixture volume and the H/{sup 239}Pu ratio, approximations to the practical problem, referred to as applications, have been made to envelop possible ranges of mixture volumes and H/{sup 239}Pu ratios. A newly developed methodology has been applied to determine the degree of applicability of benchmarks as well as the penalty that should be added to the safety margin due to insufficient benchmarks.

Goluoglu, S.



Highly labile elements  

Microsoft Academic Search

Certain elements of high lability are very responsive to thermal processes, being either highly volatile during primary nebular condensation or highly mobile by postaccretionary metamorphic or shock heating. Data for highly labile elements indicate that different thermal processes were important in the genesis of each of the chondritic groups and a discussion of each is given. Contents of highly labile

Michael E. Lipschutz; Dorothy S. Woolum



CNO abundances in H II regions of the Magellanic clouds and the galaxy with implications regarding the nucleosynthesis of the CNO element group  

NASA Technical Reports Server (NTRS)

Final abundance results of IUE observations of the UV spectra of three H II regions in the Small Magellanic Cloud and four H II regions in the Large Magellanic Cloud are presented. Calculated yields of carbon and oxygen derived are y(C)=.00063 and y(O)=.0016. The nucleosynthetic origin of nitrogen was evaluated as being predominantly a secondary element produced from carbon as its seed. Plotting log N/C versus log C/H yielded the rather unexpected result that log N/C decreases with lo C/H over the SMC-LMC-Orion range. The cause of this relationship is discussed.

Dufour, R. J.; Shields, G. A.



A D V A N C E S I N C R E A T I V I T Y A N D G I F T E D N E S S The Elements of Creativity and  

E-print Network

creativity in their classrooms, in addition to professional development specialists, mathematics educators.) Seoul National University, Korea The Elements of Creativity and Giftedness in Mathematics edited by Bharath Sriraman and KyeongHwa Lee covers recent advances in mathematics education pertaining

Bardsley, John


(Accepted for publication in the Journal of Algebra as of 7/13/98.) Minuscule Elements of Weyl Groups, the Numbers Game,  

E-print Network

motivations for this material which are independent of Lie theory. In fact, the "numbers game" viewpoint Page Proofs Version, 1/14/99 #12; 2 1. Introduction Except for some motivating comments, the only of this paper may be explained to lay people. Readers who are unfamiliar with Weyl groups should skip the next

Proctor, Robert A.


Synthesis and characterization of some new Schiff base complexes of group 13 elements, ab initio studies, cytotoxicity and reaction with hydrogen peroxide  

NASA Astrophysics Data System (ADS)

A novel tetradentate Schiff base, naphthabza-H2 = N,N'-bis(naphthylidene)-2-aminobenzylamine, and a series of aluminum(III), gallium(III), and indium(III) complexes with general formula, MLNO3, were synthesized and characterized by elemental analysis, 1H NMR, FT-IR, UV-Vis spectroscopy and thermogravimetric method. The product of the reaction of complexes with hydrogen peroxide was characterized by similar techniques. According to the ab initio calculations aluminum and gallium complexes have five-coordinated structures and indium complex is a six-coordinated one. Also, the growth inhibitory effects of the complexes toward K562 cancer cell line were measured and the results for these complexes are as follows: Al > Ga > In.

Asadi, Mozaffar; Savaripoor, Nooshin; Asadi, Zahra; Ghatee, Mohammad Hadi; Moosavi, Fatemeh; Yousefi, Reza; Jamshidi, Mehrnaz



Evaluation of essential trace and toxic elements in biological samples of normal and night blindness children of age groups 3-7 and 8-12 years.  


The most common cause of blindness in developing countries is vitamin A deficiency. The World Health Organization estimates 13.8 million children to have some degree of visual loss related to vitamin A deficiency. The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological samples composition. Vitamin and mineral deficiency prevents more than two billion people from achieving their full intellectual and physical potential. This study was designed to compare the levels of Zn, Mg, Ca, K, Na, As, Cd, and Pb in scalp hair, blood, and urine of night blindness children age ranged 3-7 and 8-12 years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of As, Ca, Cd, K, Pb, Mg, Na, and Zn in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The concentrations of trace and toxic elements were measured by atomic absorption spectrophotometer prior to microwave-assisted acid digestion. The results of this study showed that the mean values of As, Cd, Na, and Pb were significantly higher in scalp hair, blood, and urine samples of male and female night blindness children than in referents (p?elements in biological samples (scalp hair and blood) of night blindness children. PMID:20820941

Afridi, Hassan Imran; Kazi, Tasneem Gul; Kazi, Naveed; Kandhro, Ghulam Abbas; Baig, Jameel Ahmed; Shah, Abdul Qadir; Wadhwa, Sham Kumar; Khan, Sumaira; Kolachi, Nida Fatima; Shah, Faheem; Jamali, Mohammad Khan; Arain, Mohammad Balal; Sirajuddin



Selenium and sulfur concentrations in the Bushveld Complex of South Africa and implications for formation of the platinum-group element deposits  

NASA Astrophysics Data System (ADS)

We have determined the S, Se, Cu and La contents through a complete stratigraphic section of the Bushveld Complex. The principle aim was to determine which phases controlled these elements. S, Se and Cu show positive correlations, but these elements do not correlate with La. In most cases, the concentration of S, Se and Cu in rocks containing greater than 800 ppm S can be modeled by segregation of a Fe-Ni-Cu sulfide liquid from a fractionating magma. As the magma evolved, Se and Cu were depleted by the continual segregation of sulfide liquid and the S/Se and S/Cu of the rocks increased. The Se/Cu ratio is higher in the more evolved rocks, which suggests that Se has a slightly lower partition coefficient than Cu into sulfide liquid (1,200 versus 1,700). The Lower and lower Critical Zone of the complex contains on average only 99 ppm S. The low S content of these rocks has led some authors to suggest that these rocks do not contain cumulate sulfides, despite the fact that they are moderately enriched in PGE. These samples fall along the same trend as the S-rich samples on the S-versus-Se plot and the S/La and Se/La ratios are greater than the initial magmas suggesting that despite the low S contents cumulate sulfides are present. Three models may be suggested in order to explain the low S content in the Lower and Critical Zone rocks: (a) the sulfides that were present have migrated away from the cumulate pile into the footwall or center of the intrusion; (b) the magma was saturated in sulfides at depth and during transport some sulfides lagged in embayments; (c) the rocks have lost both S and Se at high temperature. The first two models have important implications for exploration.

Barnes, Sarah-Jane; Savard, Dany; Bédard, L. Paul; Maier, Wolfgang D.



Effects of electromagnetic pulse on serum element levels in rat.  


Electromagnetic pulse (EMP) was a potentially harmful factor to the human body, and a biological dosimetry to evaluate effects of EMP is necessary. Little is known about effects of EMP on concentration of macro and trace elements in serum so far. In this study, Sprague-Dawley rats were randomly divided into 50-kV/m EMP-exposed group (n = 10), 100-kV/m EMP-exposed group (n = 10), 200-kV/m EMP-exposed group (n = 40), and the sham-exposed group (n = 20). The macro and trace element concentrations in serum were examined at 6, 12, 24, and 48 h after EMP exposure at different electric field intensities. Compared with the sham-exposed groups, the concentration of sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), selenium (Se), and manganese (Mn) in rat serum was not changed significantly within 48 h after 200 pulses of EMP exposure at electric field intensity of 50, 100, and 200 kV/m although the K level was decreased and the Ca level was increased with the electric field intensity of EMP increasing. In addition, there was a tendency that the Zn level was decreased with the time going on within 48 h after EMP exposure. Under our experimental conditions, EMP exposure cannot affect the concentration of macro and trace elements in rat serum. There was no time-effect or dose-effect relationship between EMP exposure and serum element levels. The macro and trace elements in serum are not suitable endpoints of biological dosimetry of EMP. PMID:24497087

Li, Kangchu; Ma, Shirong; Ren, Dongqing; Li, Yurong; Ding, Guirong; Liu, Junye; Guo, Yao; Guo, Guozhen



Control of absorption properties of tetraazaporphyrin group 15 complexes by modification of their axial ligands.  


Tetraazaporphyrin (TAP) complexes with group 15 elements (phosphorus(v) or arsenic(v)) containing two axial OH ligands showed reversible spectroscopic changes with acid or base doping. Spectroscopic and theoretical analysis revealed that the modification of axial ligands can tune the interaction between peripheral substituents and the TAP macrocycle. PMID:25331907

Furuyama, Taniyuki; Asai, Mitsuo; Kobayashi, Nagao



Accelerator measurement of the energy spectra of neutrons emitted in the interaction of 3-GeV protons with several elements  

NASA Technical Reports Server (NTRS)

The application of time of flight techniques for determining the shapes of the energy spectra of neutrons between 20 and 400 MeV is discussed. The neutrons are emitted at 20, 34, and 90 degrees in the bombardment of targets by 3 GeV protons. The targets used are carbon, aluminum, cobalt, and platinum with cylindrical cross section. Targets being bombarded are located in the internal circulating beam of a particle accelerator.

Nalesnik, W. J.; Devlin, T. J.; Merker, M.; Shen, B. S. P.



How Deep and Hot was Earth's Magma Ocean? Combined Experimental Datasets for the Metal-silicate Partitioning of 11 Siderophile Elements - Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd  

NASA Technical Reports Server (NTRS)

Since approximately 1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients (D) for siderophile (iron-loving) elements are much different than those measured at low PT conditions. The high PT data have been used to argue for a magma ocean during growth of the early Earth. Initial conclusions were based on experiments and calculations for a small number of elements such as Ni and Co. However, for many elements only a limited number of experimental data were available then, and they only hinted at values of metal-silicate D's at high PT conditions. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements. At the same time several different models have been advanced to explain the siderophile elements in the earth's mantle: a) intermediate depth magma ocean; 25-30 GPa, b) deep magma ocean; up to 50 GPa, and c) early reduced and later oxidized magma ocean. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to update the predictive expressions outlined by Righter et al. (1997) with new experimental data from the last decade, test the predictive ability of these expressions against independent datasets (there are more data now to do this properly), and to apply the resulting expressions to the siderophile element patterns in Earth's upper mantle. The predictive expressions have the form: lnD = alnfO2 + b/T + cP/T + d(1Xs) + e(1Xc) + SigmafiXi + g These expressions are guided by the thermodynamics of simple metal-oxide equilibria that control each element, include terms that mimic the activity coefficients of each element in the metal and silicate, and quantify the effect of variable oxygen fugacity. Preliminary results confirm that D(Ni) and D(Co) converge at pressures near 25-30 GPa and approximately 2200 K, and show that D(Pd) and D(Cu) become too low at the PT conditions of the deepest models. Furthermore, models which force fit V and Cr mantle concentrations by metal-silicate equilibrium overlook the fact that at early Earth mantle fO2, these elements will be more compatible in Mg-perovskite and (Fe,Mg)O than in metal. Thus an intermediate depth magma ocean, at 25-30 GPa, 2200 K, and at IW-2, can explain more mantle siderophile element concentrations than other models.

Righter, Kevin



Microwave-assisted carbohydrohalogenation of first-row transition-metal oxides (M = V, Cr, Mn, Fe, Co, Ni, Cu) with the formation of element halides.  


The anhydrous forms of first-row transition-metal chlorides and bromides ranging from vanadium to copper were synthesized in a one-step reaction using the relatively inexpensive element oxides, carbon sources, and halogen halides as starting materials. The reactions were carried out in a microwave oven to give quantitative yields within short reaction times. PMID:24099620

Berger, Matthias; Neumeyer, Felix; Auner, Norbert



Plane Groups  

NSDL National Science Digital Library

This is a lengthy PDF document (60 pages+) about plane groups and symmetry. It includes colorful images of each of the 17 plane groups, in several different forms. Additionally, there are some summarizing graphics that show unit cells, lattices, symmetry elements, etc. There is lots here to choose from -- I doubt that anyone will want to use all of the images. Studying plane groups is a good way to introduce crystal systems, point groups, lattices, symmetry operators, etc. All is in 2-D, but it is easy to tell students that the principles are the same in 3-D. For those who like to make changes, the PDF document was created from individual EPS files. This means that the files can be opened in Adobe Illustrator, Corel Draw, etc., and modified to fit your own needs.

Perkins, Dexter


A Measurement of the Top Quark Mass with the D0 Detector at s**(1/2) = 1.96-TeV using the Matrix Element Method  

SciTech Connect

Using a data set of 158 and 169 pb{sup -1} of D0 Run-II data in the electron and muon plus jets channel, respectively, the top quark mass has been measured using the Matrix Element Method. The method and its implementation are described. Its performance is studied in Monte Carlo using ensemble tests and the method is applied to the Moriond 2004 data set.

Kroeninger, Kevin Alexander; /Bonn U.



A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. V. Determination of Minor Constitutents and Trace Elements in Steel  

Microsoft Academic Search

The applicability of the modified hollow cathode emission source to the determination of some elements usually contained in steel was tested in the case of chromium (0.144 – 3.07%), copper (0.090 – 0.49%), manganese (0.016 – 1.42%), molybdenum (0.007 – 1.41%), nickel (0.048 – 5.15%, silicon (0.013 – 0.81%), and vanadium (0.034 – 0.64%). The linearity of the calibration curves

S. Caroli; O. Senofonte; A. Alimonti; K. Zimmer



Element Research  

NSDL National Science Digital Library

You have been assigned an element during class. Your mission is to research information about your element. Create a Word document with the title of your element. Save your work regularly! Next, use the resources on this page to find and record the following information in your word document. (Hint: copy and paste the questions into your word document, then answer them.) See It s Elemental for electron configuration - ...

Wall, Mr.



Interdependence and Group Effectiveness.  

ERIC Educational Resources Information Center

Investigated the differential effects of task design and reward system design on group functioning in a large U.S. corporation; the effectiveness of "hybrid" groups (having tasks and rewards with both individual and group elements); and how individuals' autonomy preferences moderate their responses to interdependence. Groups performed best when…

Wageman, Ruth



Single element magnetic suspension actuator  

NASA Technical Reports Server (NTRS)

The invention, a single element magnetic suspension actuator with bidirectional force capability along a single axis, includes an electromagnet and a nonmagnetic suspended element. A permanent magnet mounted on the suspended element interacts with a magnetic field established by the electromagnet to produce bidirectional forces in response to a variable force command voltage V (sub FC) applied to the electromagnet. A sensor measures the position of the suspended element on the single axis which is a function of force command voltage V (sub FC).

Groom, Nelson J. (inventor)



Ring-laser gyroscope system using dispersive element(s)  

NASA Technical Reports Server (NTRS)

A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

Smith, David D. (Inventor)



Observation of a martensitic structural distortion in V, Nb, and Ta.  


Thermal-expansion measurements of the Group 5 elements V, Nb, and Ta reveal a structural distortion below 300 K. Data for single-crystalline Nb and Ta display anisotropic thermal expansion, martensitic in character, that is inconsistent with cubic crystal structures at low temperature. Published results on V show similar behavior. Interstitial impurities suppress the transition. PMID:21902404

Bollinger, R K; White, B D; Neumeier, J J; Sandim, H R Z; Suzuki, Y; dos Santos, C A M; Avci, R; Migliori, A; Betts, J B



Data Elements Search - Data Elements

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Interfacial energies of some elemental and alloy aerospace materials. Final report 30 June 1975--31 December 1977. [Ti6Al4V  

Microsoft Academic Search

Previously unreported values of the grain-boundary free energies for pure titanium and the titanium alloy Ti-6Al-4V and of the surface free energy for the titanium alloy, as well as a new value of the surface free energy for pure titanium, have been determined using the zero-creep technique for small-diameter wires and measurements of the dihedral angle at the base of




The 190Pt-186Os Decay System Applied to Dating Platinum-Group Element Mineralization in Layered Intrusions, Ophiolites and Detrital Deposits  

NASA Astrophysics Data System (ADS)

Discrete platinum-group minerals (PGM) occur as accessory phases in mafic-ultamafic intrusions and ophiolitic chromitites, as well as numerous detrital deposits globally. The 190Pt-186Os decay system, measured by laser ablation MC-ICPMS (LA-MC-ICPMS) provides a useful geochronometric tool for direct dating of PGM. Here we present two examples that verify the accuracy of the technique in geologically well constrained situations and demonstrate the potential for using the 190Pt-186Os PGM method to accurately date layered mafic intrusions, ophiolitic chromitites and detrital PGM deposits. Fifty PGM grains from three different horizons within the Bushveld complex yield a Pt-Os isochron age of 2012 ± 47 Ma (2?, MSWD = 1.19, 186Os/188Osi = 0.119818 ± 0.000006). This is consistent with the published U-Pb zircon age of 2054 Ma (Scoates and Friedman, 2008). The younger PGM isochron age is not likely to be a function of difference in blocking temperatures in the different systems. Pt-Os model ages are possible in high pt grains because initial 186Os/188Os can be well constrained. Using this approach we obtained Pt-Os model ages of 2113 ± 106 Ma and 2042 ± 102 Ma for a Bushveld Pt-Fe alloy and sperrylite respectively. Detrital PGM derived from the Meratus ophiolite, southeast Borneo yield a 190Pt-186Os isochron age of 202.5 Ma ± 8.3 Ma (2?, n = 260, MSWD = 0.90, 186Os/188Osi = 0.119830 ± 0.000003), consistent with radiometric and biostratigraphic age constraints (Wakita et al., 1998). We interpret this as the age of formation of the PGM grains in during chromitite genesis in the lower oceanic lithosphere. Our combined data demonstrate the utility of the LA-MC-ICPMS method as a tool for accurate Pt-Os dating of detrital PGM as well as their igneous parent bodies. We can constrain Pt/Os fractionation at the ablation site as being < 2.5%, while within-grain heterogeneity is ultimately one of the strongest controls on isochron and single-grain ages given the partial sampling represented by laser ablation. Scoates, J.S. and Friedman, R.M. 2008. Precise age of the platiniferous Merensky reef, Bushveld Complex, South Africa, by the U-Pb zircon chemical abrasion ID-TIMS technique; Economic Geology 103, p. 465-471. Wakita, K., Miyazaki, K., Zulkarnain, I., Sopaheluwakan, J. and Sanyoto, P. 1998. Tectonic implications of new age data for the Meratus complex of south Kalimantan, Indonesia; Island Arc 7, p. 202-222.

Coggon, J. A.; Nowell, G.; Pearson, G.; Oberthür, T.; Lorand, J.; Melcher, F.; Parman, S. W.



Group Variables and Gaming Success.  

ERIC Educational Resources Information Center

Describes a study designed to determine the effects of group cohesiveness on group performance in a management game and, to examine the effects voluntary v assigned group membership has on the cohesiveness of the group. (Author/LLS)

Norris, Dwight R.; Niebuhr, Robert E.



Selective oxidation of H 2 S to ammonium thiosulfate and elemental sulfur using mixtures of V-Bi-O and Sb 2 O 4  

Microsoft Academic Search

The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was investigated by using vanadium-bismuth\\u000a based mixed oxide catalysts. Synergistic effect on catalytic activity was observed for the mechanical mixtures of V-Bi-O and\\u000a Sb2O4. Temperature programmed oxidation (TPO), X-ray photoelectron spectroscopy (XPS), and two separated bed reactivity test results\\u000a supported the role of Sb2O4 for reoxidizing

Bong-Kuk Kim; Byung-Ha Hwang; Hwa-Soo Lee; Hee-Chul Woo; Dae-Won Park



Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinations of platinum group elements (Pt, Pd, Ru, Ir) in environmental samples.  


An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt, Pd, Ru, and Ir, respectively, using sample weights of only 0.2 g. The reliability of the ID-ICP-QMS method was demonstrated by analyzing a Canadian geological reference material and by participating in an interlaboratory study for the determination of platinum and palladium in a homogenized road dust sample. Surface soil, sampled at different distances from a highway, showed concentrations in the range of 0.1-87 ng x g(-1). An exponential decrease of the platinum and palladium concentration with increasing distance and a small anthropogenic contribution to the natural background concentration of ruthenium and iridium was found in these samples. PMID:11220823

Müller, M; Heumann, K G



Mon. Not. R. Astron. Soc. 000, 000--000 (0000) Printed 28 February 1999 (MN L A T E X style file v1.4) PreHeated Isentropic Gas in Groups of Galaxies  

E-print Network

.4) Pre­Heated Isentropic Gas in Groups of Galaxies Mike L. Balogh, Arif Babul, and David R. Patton 1 1 Department of Physics & Astronomy, University of Victoria, Victoria, BC, V8X 4M6, Canada Email: balogh,babul,patton in such objects. Key words: galaxies: clusters: general -- intergalactic medium 1 INTRODUCTION The abundance

Balogh, Michael L.


Randomized, Single-Blinded Comparative Study of the Efficacy of Amoxicillin (40 mg\\/kg\\/day) Versus Standard-Dose Penicillin V in the Treatment of Group a Streptococcal Pharyngitis in Children  

Microsoft Academic Search

A 10-day course of amoxicillin at a dosage of 40 mg per kilogram per day was compared with conventional (lower dosage) penicillin V therapy in the treatment of culture-proven Group A streptococcal pharyngitis in children 3 to 18 years of age in a prospective, randomized, and singleblinded study. Children had to have signs and symptoms compatible with the diagnosis of

Ishwar Gopichand; Gary D. Williams; Carla Saracusa; Sharon V. Medendorp; Camille Sabella; John B. Lampe; Richard E. Garcia; Lisette Lebrun; Johanna Goldfarb



Revised physical elements of the astrophysically important O9.5+O9.5V eclipsing binary system Y Cygni  

NASA Astrophysics Data System (ADS)

Context. Rapid advancements in light-curve and radial-velocity curve modelling, as well as improvements in the accuracy of observations, allow more stringent tests of the theory of stellar evolution. Binaries with rapid apsidal advance are particularly useful in this respect since the internal structure of the stars can also be tested. Aims: Thanks to its long and rich observational history and rapid apsidal motion, the massive eclipsing binary Y Cygrepresents one of the cornerstones of critical tests of stellar evolutionary theory for massive stars. Nevertheless, the determination of the basic physical properties is less accurate than it could be given the existing number of spectral and photometric observations. Our goal is to analyse all these data simultaneously with the new dedicated series of our own spectral and photometric observations from observatories widely separated in longitude. Methods: We obtained new series of UBV observations at three observatories separated in local time to obtain complete light curves of Y Cygfor its orbital period close to 3 days. This new photometry was reduced and carefully transformed to the standard UBV system using the HEC22 program. We also obtained new series of red spectra secured at two observatories and re-analysed earlier obtained blue electronic spectra. Reduction of the new spectra was carried out in the IRAF and SPEFO programs. Orbital elements were derived independently with the FOTEL and PHOEBE programs and via disentangling with the program KOREL . The final combined solution was obtained with the program PHOEBE . Results: Our analyses provide the most accurate value of the apsidal period of (47.805 ± 0.030) yr published so far and the following physical elements: M1 = 17.72 ± 0.35 M?, M2 = 17.73 ± 0.30 M?, R1 = 5.785 ± 0.091 R?, and R2 = 5.816 ± 0.063 R?. The disentangling thus resulted in the masses, which are somewhat higher than all previous determinations and virtually the same for both stars, while the light curve implies a slighly higher radius and luminosity for star 2. The above empirical values imply the logarithm of the internal structure constant log k2 = -1.937. A comparison with Claret's stellar interior models implies an age close to 2 × 106 yr for both stars. Conclusions: The claimed accuracy of modern element determination of 1-2 per cent still seems a bit too optimistic and obtaining new high-dispersion and high-resolution spectra is desirable. Based on new spectral and photometric observations from the following observatories: Dominion Astrophysical Observatory, Hvar, Ond?ejov, Fairborn, and Sejong.Appendix A is available in electronic form at http://www.aanda.orgTables 4 and 5 are available at the CDS via anonymous ftp to ( or via

Harmanec, P.; Holmgren, D. E.; Wolf, M.; Boži?, H.; Guinan, E. F.; Kang, Y. W.; Mayer, P.; McCook, G. P.; Nemravová, J.; Yang, S.; Šlechta, M.; Ruždjak, D.; Sudar, D.; Svoboda, P.



Group typicality, group loyalty and cognitive development.  


Over the course of childhood, children's thinking about social groups changes in a variety of ways. Developmental Subjective Group Dynamics (DSGD) theory emphasizes children's understanding of the importance of conforming to group norms. Abrams et al.'s study, which uses DSGD theory as a framework, demonstrates the social cognitive skills underlying young elementary school children's thinking about group norms. Future research on children's thinking about groups and group norms should explore additional elements of this topic, including aspects of typicality beyond loyalty. PMID:24935627

Patterson, Meagan M



Evolution structurale et nature des liaisons de quelques composés polyanioniques des systèmes IIB-V-VII  

NASA Astrophysics Data System (ADS)

The structural data for known cadmium and mercury polyanionic compounds are reported and classified with respect to the coordination of these atoms with elements of group V. These data are discussed according to the particular characteristics of elements IIB as well as the size of associated halogens. The character of IIB-V, V-V, and IIB-VII bonds in these compounds is also analyzed. Les données structurales des composés polyanioniques connus du cadmium et du mercure sont rassemblées d'aprés les motifs de coordination présentés par ces atomes vis à vis des éléments V. Ces données sont discutées en fonction des caractéristiques propres des éléments IIB ainsi qu'en fonction de la dimension de l'halogène associé. Le caractère des liaisons IIB-V, V-V, et IIB-VII présentes dans ces composés est également analysé.

Rebbah, H.; Rebbah, A.



[Removal of gaseous elemental mercury over cerium doped low vanadium loading V2O5-WO3/TiO2 in simulated coal-fired flue gas].  


This paper discussed a recent study of mercury removal by gaseous hydrogen chloride over novel Ce doped low vanadium V2O5-WO3/TiO2 catalysts under a bench scale condition. The performances on Hg(0) removal over the catalyst were tested in simulated flue gas with 80-100 microg x m(-3) Hg(0), 8% O2, 10 x10(-6) HCl, 8% H2O, 800 x10(-6) SO2 and balanced with N2. Results showed that about 95% of Hg(0) could be removed. According to the characterization results, BET surface areas had not significant influence on catalytic performance. XPS results indicated that Ce4+ oxide was a mainly form in the catalysts surface, which was beneficial for Hg(0) removal reactions. Water vapor slightly inhibited Hg(0) removal efficiency, due to the competitive adsorption, however, SO2 promoted the oxidation reactions, resulting in higher removal efficiencies. PMID:22165254

Wan, Qi; Duan, Lei; He, Ke-Bin; Chen, Liang; Li, Jun-Hua



Elemental health  

SciTech Connect

Trace elements used in nutritional supplements and vitamins are discussed in the article. Relevant studies are briefly cited regarding the health effects of selenium, chromium, germanium, silicon, zinc, magnesium, silver, manganese, ruthenium, lithium, and vanadium. The toxicity and food sources are listed for some of the elements. A brief summary is also provided of the nutritional supplements market.

Tonneson, L.C.



Effects of long-lived 10 MeV-scale sterile neutrinos on primordial elemental abundances and the effective neutrino number  

NASA Astrophysics Data System (ADS)

The primordial lithium abundance inferred from spectroscopic observations of metal-poor stars is ˜3 times smaller than the theoretical prediction in the standard big bang nucleosynthesis (BBN) model. We assume a simple model composed of standard model particles and a sterile neutrino ?H with mass of O(10) MeV which decays long after BBN. We then investigate cosmological effects of a sterile neutrino decay, and check if a sterile neutrino can reduce the primordial lithium abundance. We formulate the injection spectrum of nonthermal photon induced by the ?H decay. We take into account the generation of electrons and positrons, e±'s, and active neutrinos at the ?H decay, the primary photon production via the inverse Compton scattering of cosmic background radiation (CBR) by energetic e±, and electromagnetic cascade showers induced by the primary photons. The steady state injection spectrum is then derived as a function of the ?H mass and the photon temperature. The ?H decay produces energetic active neutrinos which are not thermalized, and e±'s which are thermalized. We then derive formulas relevant to the ?H decay rates and formulas for the baryon-to-photon ratio ? and effective neutrino number Neff. The initial abundance, mass, and lifetime of ?H are taken as free parameters. We then consistently solve (1) the cosmic thermal history, (2) nonthermal nucleosynthesis induced by the nonthermal photons, (3) the ? value, and (4) the Neff value. We find that an effective Be7 destruction can occur only if the sterile neutrino decays at photon temperature T =O(1) keV. Amounts of energy injection at the ?H decay are constrained from limits on primordial D and Li7 abundances, the Neff value, and the CBR energy spectrum. We find that Be7 is photodisintegrated and the Li problem is partially solved for the lifetime 104-105 s and the mass ?14 MeV. Be7 destruction by more than a factor of 3 is not possible because of an associated D overdestruction. In the parameter region, the ? value is decreased slightly, while the Neff value is increased by a factor of ?Neff?1. In this study, errors in photodisintegration cross sections of Be7(? ,?)He3 and Li7(? ,?)H3 that have propagated through the literature are corrected, and new functions are derived based on recent nuclear experiments. It is found that the new photodisintegration rates are 2.3 to 2.5 times smaller than the old rates. The correct cross sections thus indicate significantly smaller efficiencies of Be7 and Li7 photodisintegration. Abundances of sterile neutrino necessary for the Li7 reduction are much smaller than thermal freeze-out abundances. The relic sterile neutrino, therefore, must be diluted between the freeze-out and BBN epochs by some mechanism.

Ishida, Hiroyuki; Kusakabe, Motohiko; Okada, Hiroshi



L?, L?, L? and L? X-ray production cross-sections and yields of some selected elements between caesium and erbium following ionization by 59.54 keV ? rays  

NASA Astrophysics Data System (ADS)

Ll, L?, L? and L? X-ray production cross-sections were measured in elements from Cs to Er following ionization for 59.54 keV ?-rays from an 241Am point source. The measured values are compared with theoretical predictions estimated using subshell photoionization cross-sections, fluorescence yields, Coster-Kronig transition probabilities, K to Li subshell vacancy transfer probabilities and radiative decay rates. Average L-shell fluorescence yields were deduced from present measured total L X-ray production cross-sections, theoretical K and L photoionization cross-sections and K to L vacancy transfer probabilities. The obtained results for L X-ray production cross-sections and average L-shell fluorescence yields are compared with recent experimental values, theoretical predictions, and semiempirical fits.

Durak, Ridvan; Özdemir, Yüksel



Determination of Specific Forces and Tool Deflections in Micro-milling of Ti-6Al-4V alloy using Finite Element Simulations and Analysis  

NASA Astrophysics Data System (ADS)

Titanium alloys offer superb properties in strength, corrosion resistance and biocompatibility and are commonly utilized in medical devices and implants. Micro-end milling process is a direct and rapid fabrication method for manufacturing medical devices and implants in titanium alloys. Process performance and quality depend upon an understanding of the relationship between cutting parameters and forces and resultant tool deflections to avoid tool breakage. For this purpose, FE simulations of chip formation during micro-end milling of Ti-6Al-4V alloy with an ultra-fine grain solid carbide two-flute micro-end mill are investigated using DEFORM software. At first, specific forces in tangential and radial directions of cutting during micro-end milling for varying feed advance and rotational speeds have been determined using designed FE simulations for chip formation process. Later, these forces are applied to the micro-end mill geometry along the axial depth of cut in 3D analysis of ABAQUS. Consequently, 3D distributions for tool deflections & von Misses stress are determined. These analyses will yield in establishing integrated multi-physics process models for high performance micro-end milling and a leap-forward to process improvements.

Farina, Simone; Thepsonti, Thanongsak; Ceretti, Elisabetta; Özel, Tugrul



Platinum-group element (PGE) geochemistry of Deccan orangeites, Bastar craton, central India: Implication for a non-terrestrial origin for iridium enrichment at the K-Pg boundary  

NASA Astrophysics Data System (ADS)

We report platinum group element (PGE) concentrations of twelve bulk-rock samples from the Behradih and Kodomali orangeite intrusions in the Mainpur field, Bastar craton, central India, which are emplaced synchronously with the Deccan flood basalts. Their palladium-group PGE (PPGE) (1.8-5.2 ppb Pt, 1.2-6.4 ppb Pd) contents are distinctly higher compared to their iridium-group PGE (IPGE) concentrations (0.8-2 ppb Os, 0.8-1.2 ppb Ir, 3.2-4.2 ppb Ru, and 0.2-0.8 ppb Rh). Their PGE contents as well as Pd/Ir ratios are either similar or even lower than those from the Mesoproterozoic and Cretaceous kimberlites and orangeites from the Kaapvaal craton (southern Africa), Cretaceous kimberlites from the Sao Fransisco craton (Brazil), Ordovician kimberlites from the North China craton and the Mesoproterozoic southern Indian kimberlites from the Eastern Dharwar craton. Anomalously elevated iridium (and other PGE) contents in sediments at the Cretaceous-Paleogene (K-Pg) boundary are commonly attributed either to a large bolide impact triggering the K-Pg mass extinction or to terrestrial causes such as volcanic eruptions (Deccan flood basalts) or even to mantle-plume derived lithospheric gaseous explosions (Verneshots). Lack of unusually high abundances of PGE in the Mainpur orangeties as well as in the co-eval Deccan flood basalts and associated alkaline rocks implies that the anomalous iridium enrichment reported at the K-Pg boundary sections was not sourced from the mantle and likely originated from an extraterrestrial source.

Chalapathi Rao, N. V.; Lehmann, B.; Balaram, V.



Local Group(s)  

E-print Network

The properties of the galaxies of the Local Group are reviewed, followed by a brief discussion of nearby groups. The galaxy groups in our vicinity - the M81 group, the Cen A group, and the IC 342/Maffei group - are in many respects Local Group analogs: Their luminosity functions, galaxy content, fractional galaxy type distribution, crossing times, masses, and zero-velocity surface radii are similar to those of the Local Group. Also, the nearby groups usually consist of two subgroups, some of which approach each other and may ultimately merge to form a fossil group. These poor groups contrast with the less evolved, loose and extended galaxy ``clouds'' such as the Scl group and the CVn I cloud. These are characterized by long crossing times, are dominated by gas-rich, late-type galaxies, and lack gas-deficient, low luminosity early-type dwarfs. These clouds may be groups still in formation. The local Hubble flow derived from the clouds and groups is very cold.

Eva K. Grebel



Representations of groups of order 16  

E-print Network

to the scheme C = B A of the previous section, We choose the first procedure, using Table II according to the correspondence: Element Coset 1 ~ 1, 3 2 ~ 14, 16 3 ~ 9, 11 6, 8 5 ~ 2, 4 6 ~ 13, 15 7 ~ 10, 12 8 ~ 5, 7 Again. , we still have two two... 3 4 5 6 7 8 9 10 11 12 13 14 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Generating Relations: 2 = 1 Conjugacy Classes: All elements are self-conjugate. TABLE V-B SUBGROUP ANALYSIS OF GROUP ONE Index Elements 1 3 5 7 9 11 13 15 1 5 9 13 1 9...

McCarthy, Edmond Robert



Nineteen trace elements in marine copepods collected from the coastal waters off northeastern Taiwan  

NASA Astrophysics Data System (ADS)

This study analyzed nineteen trace elements in marine copepods collected from the coastal waters off Northeastern Taiwan. The bioconcentration factors (BCF) of the analyzed elements in copepods are discussed. Owing to the upwelling intrusion of Kuroshio Water, the study area presented an enriched copepod community and the copepod abundance ranged within 106-4890 ind. m-3. The trace elements content in the analyzed copepods varied substantially, ranging from 0.01 to 780 mg kg-1. and the average concentration followed the sequence: Sr>Fe>Zn>Cr>Li>Ni>Mn>Ba>Cu>Se>As>V>Pb>Rb>Cd>Co>Ga>Ag>Cs. The trace elements can be divided into five groups according to the concentration quantity in copepods: (1) Sr; (2) Fe, Zn, Cr, Li and Ni; (3) Mn, Cu, Ba, Se, As, V, Pb and Rb; (4) Cd, Co and Ga; (5) Ag and Cs. The concentration difference in each group is nearly one order of magnitude. The trace element concentrations in copepods seem to be in proportion to the dissolved concentrations in seawater. The trace element log BCF values ranged within 1.32-5.66. Transition metals generally have a higher BCF value than the associated minor elements, such as Ba, Sr, Li and Rb. The trace element BCF value in copepods is in inverse proportion to the dissolved concentrations in seawater.

Fang, Tien-Hsi; Hsiao, Shih-Hui; Nan, Fan-Hua



Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\\bar{p}$ Collisions at $\\sqrt{s} = 1.96$ TeV  

SciTech Connect

This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a dataset corresponding to an integrated luminosity of 5.6 fb{sup -1}. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on {sigma}(p{bar p} {yields} WH) x {Beta}(H {yields} b{bar b}). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between m{sub H} = 100 GeV/c{sup 2} and m{sub H} = 150 GeV/c{sup 2}. The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.

Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U.; Artikov, A.; /Dubna, JINR /Texas A-M



Element Hangman  

NSDL National Science Digital Library

The Thomas Jefferson National Accelerator Facility, known as the Jefferson Lab, is funded by the Office of Science for the US Department of Energy. Its corresponding Web site and educational offerings include the interactive Element Hangman game. This simple exercise requires kids to enter the correct letters of an element before all ten pieces of the animated figure are gone. However, the highlight of the site is that, once the correct element is spelled, students get to click the "tell me more about" button for additional information. A separate window opens, which gives a wealth of facts about that element such as its physical properties, who discovered it, and what it's used in. This and other related games provided by the site offer a great way for kids to have fun while learning.


Mass determination of hypervelocity microparticles using a piezoelectric PZT element  

NASA Astrophysics Data System (ADS)

A mass observed with a piezoelectric element is discussed using hypervelocity particles accel-erated by the Van de Graaff accelerator. Since the response of the PZT element is velocity-dependent, the particle mass can be derived using calibration formulas that depend on the velocity. When the velocity during collision exceeds 20 km/s, the piezoelectric element produces a pulsed signal. Then, the rise time and the amplitude of the pulsed signal are well correlated. If the rise time and the amplitude are measured pair off, the response to the collision is classified into three groups [1]. If the calibration formulas can be established in each group, the mass is determined. Let define the deviation by (1) (mm-m0)/m0 (1) where mm is the mass value obtained using the calibration formulas of each group and m0 is that by the time of flight method, respectively. The deviation distributes like a Gaussian form. The mass can be reproduced within 40 When the velocity is less than 10 km/s, the output is of a characteristic form, with which the collision time is exactly determined. The amplitude is subject not only to the particle momentum p but also to the charge q of particle. Then, the PZT element is sensitive to q before the particle arrives at the element during flight time t, if q ? 50 fC. Since the sensitive distance d is calibrated with respect to q, the velocity v and the mass m are obtained; v = d /t, and m = p/v. The deviation defined by (1) distributes like a Gaussian form. The mass can be reproduced described above. Reference [1] T.Miyachi et al., submitted for publication in Adv. Space Res.

Miyachi, Takashi; Takechi, Seiji; Kawachi, Yuya; Shibata, Hiromi; Okudaira, Osamu; Kobayashi, Masanori; Nakamura, Maki; Iwai, Takeo; Gruen, Eberhard; Srama, Ralf


elemental discoveries  

NSDL National Science Digital Library

Experienced science journalist David Bradley serves up this resource on current chemical happenings. Tracking some of the discoveries and controversies at the forefront of chemistry, each issue of elemental discoveries summarizes a range of newsworthy topics, from gene control and tubular sensors to singing fish. In addition to the current issue, readers may browse past issues beginning December 1997. Two additional sections, Elemental Reviews and Book Sale, provide brief commentary on or descriptions (with UK prices) of related resources.


August, 2009 1. "Boundary element analysis of inclusions with corners" Engineering Analysis with Boundary Elements  

E-print Network

August, 2009 1 1. "Boundary element analysis of inclusions with corners" Engineering Analysis with Boundary Elements v31, pp 762­770,(2007) (With J. Maddi). 2. "Boundary element analysis of bonded joints. "An hr-method of Mesh Refinement for Boundary Element Method" Int. J. for Numerical Methods

Endres. William J.


KAOS/LIB-V: A library of nuclear response functions generated by KAOS-V code from ENDF/B-V and other data files  

SciTech Connect

KAOS/LIB-V: A library of processed nuclear responses for neutronics analyses of nuclear systems has been generated. The library was prepared using the KAOS-V code and nuclear data from ENDF/B-V. The library includes kerma (kinetic energy released in materials) factors and other nuclear response functions for all materials presently of interest in fusion and fission applications for 43 nonfissionable and 15 fissionable isotopes and elements. The nuclear response functions include gas production and tritium-breeding functions, and all important reaction cross sections. KAOS/LIB-V employs the VITAMIN-E weighting function and energy group structure of 174 neutron groups. Auxiliary nuclear data bases, e.g., the Japanese evaluated nuclear data library JENDL-2 were used as a source of isotopic cross sections when these data are not provided in ENDF/B-V files for a natural element. These are needed mainly to estimate average quantities such as effective Q-values for the natural element. This analysis of local energy deposition was instrumental in detecting and understanding energy balance deficiencies and other problems in the ENDF/B-V data. Pertinent information about the library and a graphical display of the main nuclear response functions for all materials in the library are given. 35 refs.

Farawila, Y.; Gohar, Y.; Maynard, C.



Finite element meshing of three-dimensional faulted domains Peter van Thienen and Thomas Geenen. Faculty of Geosciences, Mantle dynamics group, Utrecht University, The Netherlands.,  

E-print Network

Finite element meshing of three-dimensional faulted domains Peter van Thienen and Thomas, Abstract Meshing of 3-D spaces for finite element applications is often a complicated to facilitate the step from geodynamical maps to finite element meshes (box 1). The second is a mesh generator

van Thienen, Peter


Travel-related MERS-CoV cases: an assessment of exposures and risk factors in a group of Dutch travellers returning from the Kingdom of Saudi Arabia, May 2014  

PubMed Central

Background In May 2014, Middle East respiratory syndrome coronavirus (MERS-CoV) infection, with closely related viral genomes, was diagnosed in two Dutch residents, returning from a pilgrimage to Medina and Mecca, Kingdom of Saudi Arabia (KSA). These patients travelled with a group of 29 other Dutch travellers. We conducted an epidemiological assessment of the travel group to identify likely source(s) of infection and presence of potential risk factors. Methods All travellers, including the two cases, completed a questionnaire focussing on potential human, animal and food exposures to MERS-CoV. The questionnaire was modified from the WHO MERS-CoV questionnaire, taking into account the specific route and activities of the travel group. Results Twelve non-cases drank unpasteurized camel milk and had contact with camels. Most travellers, including one of the two patients (Case 1), visited local markets, where six of them consumed fruits. Two travellers, including Case 1, were exposed to coughing patients when visiting a hospital in Medina. Four travellers, including Case 1, visited two hospitals in Mecca. All travellers had been in contact with Case 1 while he was sick, with initially non-respiratory complaints. The cases were found to be older than the other travellers and both had co-morbidities. Conclusions This epidemiological study revealed the complexity of MERS-CoV outbreak investigations with multiple potential exposures to MERS-CoV reported such as healthcare visits, camel exposure, and exposure to untreated food products. Exposure to MERS-CoV during a hospital visit is considered a likely source of infection for Case 1 but not for Case 2. For Case 2, the most likely source could not be determined. Exposure to MERS-CoV via direct contact with animals or dairy products seems unlikely for the two Dutch cases. Furthermore, exposure to a common but still unidentified source cannot be ruled out. More comprehensive research into sources of infection in the Arabian Peninsula is needed to strengthen and specify the prevention of MERS-CoV infections. PMID:25328533



Transactinide Elements and Future Elements  

NASA Astrophysics Data System (ADS)

This chapter gives a brief summary of the reported discoveries, confirmation, and nuclear properties of the claimed and confirmed transactinide elements through the year 2004. However, the primary emphasis is on the chemical properties - experimental, theoretical, and predicted - of the transactinides and a comparison of measured properties with theoretical predictions. The experimental studies of chemical properties are especially challenging because of the low production rates and the short half-lives and the need for very special facilities and the use of atom-at-a-time chemistry. The discovery of a new element must furnish evidence that its atomic number is different from those of all the currently known elements and first claims to discovery often lacked such positive identification. As a result, there were uncertainties and controversies over priority of discovery, nuclear and chemical properties, and assignment of names. The first positive identification of the atomic number of all these elements was accomplished using ‘physical' rather than chemical techniques.

Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria


Fast-neutron scattering cross sections of elemental silver  

SciTech Connect

Differential neutron elastic- and inelastic-scattering cross sections of elemental silver are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV and at 10 to 20 scattering angles distributed between 20 and 160/sup 0/. Inelastically-scattered neutron groups are observed corresponding to the excitation of levels at; 328 +- 13, 419 +- 50, 748 +- 25, 908 +- 26, 1150 +- 38, 1286 +- 25, 1507 +- 20, 1623 +- 30, 1835 +- 20 and 1944 +- 26 keV. The experimental results are used to derive an optical-statistical model that provides a good description of the observed cross sections. The measured values are compared with corresponding quantities given in ENDF/B-V.

Smith, A.B.; Guenther, P.T.



Quantum Complexity of Testing Group Commutativity  

E-print Network

, and the en- coding of group elements is not necessarily unique: different strings may encode the same group-box groups was introduced by Babai and Szemer´edi [4]. In this model, the elements of a group are encodedQuantum Complexity of Testing Group Commutativity Fr´ed´eric Magniez1 and Ashwin Nayak2 1 CNRS

Magniez, Frédéric



E-print Network

group G. Since Q is a perfect field, every element a of Q[G] has a unique additive Jordan decomposition], and using variants of many of the same ar- guments, [LP1] came close to determining all nonabelian 3-groups group algebra Q[G0], we let T denote the sum of the group elements of T. As is well known, (1 - t)T = 0

Passman, Donald S.


Three-year results comparing platinum-chromium PROMUS element and cobalt-chromium XIENCE V everolimus-eluting stents in de novo coronary artery narrowing (from the PLATINUM Trial).  


In the randomized PLATINUM trial, the PROMUS Element platinum-chromium everolimus-eluting stent (PtCr-EES; Boston Scientific, Natick, Massachusetts) was noninferior to the XIENCE V cobalt-chromium everolimus-eluting stent (CoCr-EES; Boston Scientific and Abbott Vascular, Santa Clara, California) for the primary end point of 1-year target lesion failure. This study reports the 3-year outcomes. Patients (n=1,530) with 1 or 2 de novo native coronary artery lesions (baseline vessel diameter?2.50 mm to ?4.25 mm and length?24 mm) were randomized 1:1 to PtCr-EES versus CoCr-EES. Three-year follow-up was available in 93.9% (703 of 749) of patients with CoCr-EES and 96.7% (733 of 758) of patients with PtCr-EES. Comparing CoCr-EES with PtCr-EES, 3-year rates of death (4.3% vs 3.7%, hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.52 to 1.48, p=0.62), cardiac death (1.9% vs 1.2%, HR 0.63, 95% CI 0.27 to 1.45, p=0.27), myocardial infarction (2.5% vs 2.3%, HR 0.92, 95% CI 0.48 to 1.79, p=0.81), ischemia-driven target lesion revascularization (4.9% vs 3.5%, HR 0.72, 95% CI 0.43 to 1.20, p=0.21), and Academic Research Consortium definite or probable stent thrombosis (0.5% vs 0.7%, HR 1.23, 95% CI 0.33 to 4.57, p=0.76) were not significantly different. In conclusion, 3-year results of the PLATINUM randomized, controlled, clinical trial demonstrate comparable safety and efficacy outcomes of the PROMUS Element PtCr-EES and the XIENCE V CoCr-EES. PMID:24530167

Meredith, Ian T; Teirstein, Paul S; Bouchard, Alain; Carrié, Didier; Möllmann, Helge; Oldroyd, Keith G; Hall, Jack; Allocco, Dominic J; Dawkins, Keith D; Stone, Gregg W



Six Essential Elements- National Geographic Photograph Activity  

NSDL National Science Digital Library

This lesson is the fourth in a unit of five lessons on the Six Essential Elements of Geography. In this lesson students will apply recently acquired knowledge regarding the Six Essential Elements of Geography. They will utilize National Geographic magazines to find examples of the six Elements and write to explain how the photograph fits the element. First, they will do this activity in groups; groups will each be assigned one Element. Second, students will individually find an example of all six Elements. At the end of the lesson, students will present their work to the class.

Steed, Patricia



Element Research.  

ERIC Educational Resources Information Center

Describes a research assignment for 8th grade students on the elements of the periodic table. Students use web-based resources and a chemistry handbook to gather information, construct concept maps, and present the findings to the full class using the mode of their choice: a humorous story, a slideshow or gameboard, a brochure, a song, or skit.…

Herald, Christine



Element Report  

NSDL National Science Digital Library

Use these resources to fill out your Element Report outline Today's project is slightly different than those you've done in the past. You are not required to follow these sites in order. You can use any or all of them to find out the information needed for your outline. You should access at least three of the sites. The first four sites ...

Petersen, Mrs.



Orbital Elements  

NSDL National Science Digital Library

Coordinates for tracking the International Space Station and the Mir Space Station are available here from NASA's Johnson Space Center Flight Design and Dynamics Division. The Orbital Elements page offers real-time data for use in ground track plotting programs. The site cautions the data are for ground track plotting programs only and "should not be used for precise applications or analysis!"


Blockade of glutamate transporters leads to potentiation of NMDA receptor current in layer V pyramidal neurons of the rat prefrontal cortex via group II metabotropic glutamate receptor activation  

Microsoft Academic Search

Membrane currents of layer V pyramidal cells in slices of the rat prefrontal cortex (PFC) were recorded with the patch-clamp technique. In an Mg2+-free superfusion medium l-trans-pyrrolidine-2,4-dicarboxylic acid (PDC), a preferential blocker of astrocytic glutamate transporters, caused inward current due to the activation of NMDA receptors. The blockade of conducted action potentials by tetrodotoxin did not interfere with this effect.

Joao F. Oliveira; Ute Krügel; Laszlo Köles; Peter Illes; Kerstin Wirkner



Correlation of trace elements in hair with colon cancer  

SciTech Connect

The trace element content of 116 hair samples from patients with colon cancer and from referent series of patients who had a variety of other diseases were measured using proton-induced x-ray emission (PIXE). The patients had been on largely uncontrolled diets, and the interest was whether there were differences in trace element concentrations attributable to the effects of colon cancer. The concentrations of K, Ca, Mn, Fe, Cu, Zn, Se, Br, and Rb were determined using a beam of 2.5-MeV protons. Minimum detectable limits (MDL) of 0.3 ppM were obtained for Zn and Se. Cluster analysis of the data set did not reveal any significant differences between the cancer and control groups. Mean values and ranges obtained for the elemental concentrations show good agreement with other published determinations. 20 refs., 3 figs., 3 tabs.

Kwiatek, W.M.; Cholewa, M.; Kajfosz, J.; Jones, K.W.; Shore, R.E.; Redrick, A.L.



Glueball matrix elements: a lattice calculation and applications  

E-print Network

We compute the matrix elements of the energy-momentum tensor between glueball states and the vacuum in SU(3) lattice gauge theory and extrapolate them to the continuum. These matrix elements may play an important phenomenological role in identifying glue-rich mesons. Based on a relation derived long ago by the ITEP group for J/psi radiative decays, the scalar matrix element leads to a branching ratio for the glueball that is at least three times larger than the experimentally observed branching ratio for the f_0 mesons above 1GeV. This suggests that the glueball component must be diluted quite strongly among the known scalar mesons. Finally we review the current best continuum determination of the scalar and tensor glueball masses, the deconfining temperature, the string tension and the Lambda parameter, all in units of the Sommer reference scale, using calculations based on the Wilson action.

Harvey B. Meyer



Semi-empirical and empirical L X-ray production cross sections for elements with 50 ? Z ? 92 for protons of 0.5 3.0 MeV  

NASA Astrophysics Data System (ADS)

We present in this contribution, semi-empirical production cross sections of the main X-ray lines L?, L? and L? for elements from Sn to U and for protons with energies varying from 0.5 to 3.0 MeV. The theoretical X-ray production cross sections are firstly calculated from the theoretical ionization cross sections of the L i ( i = 1, 2, 3) subshell within the ECPSSR theory. The semi-empirical L?, L? and L? cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values and give the better representation of the experimental data in some cases. On the other hand, the experimental data are directly fitted to deduce the empirical L X-ray production cross sections. A comparison is made between the semi-empirical cross sections, the empirical cross sections reported in this work and the empirical ones reported by Reis and Jesus [M.A. Reis, A.P. Jesus, Atom. Data Nucl. Data Tables 63 (1996) 1] and those of Strivay and Weber [Strivay, G. Weber, Nucl. Instr. and Meth. B 190 (2002) 112].

Nekab, M.; Kahoul, A.



Group Assignment-1 Group A Group B Group C  

E-print Network

Group Assignment-1 Group A Group B Group C Shirkhodai, Arta ( artashir ) Kurozumi, Dean ( kurozumi ) Trang, Derrick ( trangd ) Yim, Gilbert ( gyim ) Marchant, Richard ( rmarchan) Young, Garrett ( garrettz

Zhang, Rui


Group Assignment-2 Group A Group B Group C  

E-print Network

Group Assignment-2 Group A Group B Group C Shirkhodai, Arta ( artashir ) Kurozumi, Dean ( kurozumi ( cobatake ) Shultz, Allen ( shultzam ) Yamakawa, Kelsie ( kayama ) Young, Garrett ( garrettz ) Walser, Ryan

Zhang, Rui


[Determination of 16 elements in the different pine pollen by TXRF].  


After microwave digestion, 16 elements in pine pollen were simultaneously determined by TXRF. The results show that all the 16 elements were found in all pine pollens. There was a significant difference in the average content of the element such as Ca, Ti, Mn, Zn and Rb between different groups of pine pollen (P < or = 0.01). There was a difference in the average content of the element such as K, V, Fe, Co, Cu and Sr between them (P < or = 0.05). And there was no difference in the average content of the element such as Cr, Ni, As, Pb and Se between them. The results also show that pine pollen has the spectral characteristics of warm property or cold property drug. They were closely related to the tree species and the growth environment or the growth area. PMID:23156792

Chen, Wei; Han, Xiao-feng; Lü, Jian-gang; Liu, Wei-wei; Tian, Yu-hong; Wu, Xu-ran



Object grouping contingent upon background  

Microsoft Academic Search

This study analyzes grouping between singletons (line elements popping out by orientation gradient) when they segregate from textures of uniformly oriented line elements. In the first experiment three adjacent singletons formed a texture bar; in the second experiment the distance between two singletons to be grouped was manipulated. The observer's task was to discriminate the orientation of the global pattern

Giovanni Caputo



Elements and You  

NSDL National Science Digital Library

Students are introduced to the periodic table and the concept of atomic elements. The group discusses how all material in the Universe is composed of elements and that the atom is the smallest particle that still has the physical and chemical properties of any given element. As an exercise in statistics, the students participate in a counting experiment in which they sample a 'Universe bead mix' (where each bead color represents a different element present in the Universe) to estimate the overall composition of the Universe. They compare their findings of the Universe's overall composition with the composition of various different objects in the Universe that are represented by mixtures of rice, beans and other dried goods in jars. Finally, students are introduced to the idea that hydrogen fusion creates heavier elements inside a star. This activity is part of a series that has been designed specifically for use with Girl Scouts, but the activities can be used in other settings. Most of the materials are inexpensive; however, some portions of the preparation can be time intensive. It is recommended that a leader with astronomy knowledge lead the activities, or at least be available to answer questions, whenever possible.


The symmetric group Representation Theory  

E-print Network

)(46)(134)(256) = (16)(2734). Recall that if g is an element of a group G, then the conjugacy class cl(g) of g)(256), then = (1527)(46)(134)(256) = (16)(2734). Recall that if g is an element of a group G, then the conjugacy class to us, so we point out that in Sn, two elements and are conjugate if and only if they have the same

Cossey, James P.


The Zurich Environmental Study (ZENS) of Galaxies in Groups along the Cosmic Web. V. Properties and Frequency of Merging Satellites and Centrals in Different Environments  

E-print Network

We use the Zurich ENvironmental Study (ZENS) database to investigate the dependence of the merger fraction and merging galaxy properties on environment in a sample of ~1300 group galaxies with $M>10^{9.2}$ $M_{\\odot}$ and 0.05$10^{13.5}$ $M_{\\odot}$, indicating a suppression of merger activity in massive groups. The observed dependence on halo mass is almost independent of galaxy mass and merger stage. At galaxy masses >$10^{10.2}$ $M_{\\odot}$, most mergers are `dry' accretions of quenched satellites onto quenched centrals, leading to a strong increase of the merger fraction with decreasing group-centric distance at these mass scales. Both satellite and central galaxies in these high mass mergers do not differ in color and structural properties from a control sample of non-merging galaxies of equal mass and rank. At galaxy masses < $10^{10.2}$ $M_{\\odot}$ -- where we mostly probe satellite-satellite pairs and mergers between star forming systems -- close pairs (projected distance <10-20 kpc) show instea...

Pipino, A; Tacchella, S; Carollo, C M; Lilly, S J; Miniati, F; Silverman, J D; van Gorkom, J H; Finoguenov, A



Trading group theory for randomness  

Microsoft Academic Search

In a previous paper [BS] we proved, using the elements of the theory of nilpotent groups, that some of the fundamental computational problems in matriz groups belong to NP. These problems were also shown to belong to coNP, assuming an unproven hypothesis concerning finite simple g