| 11. |
- Tavani, M., et al.
(författare)
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Detection of Gamma-Ray Emission from the Eta-Carinae Region
- 2009
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Ingår i: ASTROPHYSICAL JOURNAL LETTERS. - 2041-8205. ; 698:2, s. L142-L146
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of extensive observations by the gamma-ray AGILE satellite of the Galactic region hosting the Carina nebula and the remarkable colliding wind binary Eta Carinae (eta Car) during the period 2007 July-2009 January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the position of eta Car. If 1AGL J1043-5931 is associated with the Car system, our data provide the long sought first detection above 100 MeV of a colliding wind binary. The average gamma-ray flux above 100 MeV and integrated over the preperiastron period 2007 July-2008 October is F(gamma) = (37 +/- 5) x 10(-8) ph cm(-2) s(-1) corresponding to an average gamma-ray luminosity of L(gamma) = 3.4 x 10(34) erg s(-1) for a distance of 2.3 kpc. We also report a two-day gamma-ray flaring episode of 1AGL J1043-5931 on 2008 October 11-13 possibly related to a transient acceleration and radiation episode of the strongly variable shock in the system.
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| 12. |
- Szatmari, Peter, et al.
(författare)
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Mapping autism risk loci using genetic linkage and chromosomal rearrangements.
- 2007
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 39:3, s. 319-328
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,168 families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
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| 13. |
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| 14. |
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| 15. |
- Filippov, Sergey K, et al.
(författare)
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Aggregation of dextran hydrophobically modified by sterically-hindered phenols in aqueous solutions : Aggregates vs. single molecules
- 2008
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Ingår i: European Polymer Journal. - : Elsevier BV. - 0014-3057 .- 1873-1945. ; 44:10, s. 3361-3369
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Tidskriftsartikel (refereegranskat)abstract
- The hydrodynamic properties of dextrans hydrophobically modified by sterically-hindered phenols in aq. soln. were characterized by a combination of Cryogenic Transmission Electron Microscopy (Cryo-TEM), fluorescent spectroscopy, and Dynamic Light Scattering (DLS). All solns. investigated contained aggregates the structure, shape, and crit. aggregation concn. of which are influenced by the amt. of the inserted phenol groups in the polymer matrix. We found that increasing of temp. enhances aggregation. It was established that the crit. aggregation concn. could be well approximated by a logarithmic function of the substitution degree of the glycoside units. The results suggest that the proportion of aggregates is nevertheless negligible in comparison with the proportion of single mols.
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| 16. |
- Friedman, James S., et al.
(författare)
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Premature truncation of a novel protein, RD3, exhibiting subnuclear localization is associated with retinal degeneration
- 2006
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Ingår i: American Journal of Human Genetics. - 0002-9297. ; 79:6, s. 1059-1070
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Tidskriftsartikel (refereegranskat)abstract
- The rd3 mouse is one of the oldest identified models of early-onset retinal degeneration. Using the positional candidate approach, we have identified a C -> T substitution in a novel gene, Rd3, that encodes an evolutionarily conserved protein of 195 amino acids. The rd3 mutation results in a predicted stop codon after residue 106. This change is observed in four rd3 lines derived from the original collected mice but not in the nine wild-type mouse strains that were examined. Rd3 is preferentially expressed in the retina and exhibits increasing expression through early postnatal development. In transiently transfected COS-1 cells, the RD3-fusion protein shows subnuclear localization adjacent to promyelocytic leukemia-gene-product bodies. The truncated mutant RD3 protein is detectable in COS-1 cells but appears to get degraded rapidly. To explore potential association of the human RD3 gene at chromosome 1q32 with retinopathies, we performed a mutation screen of 881 probands from North America, India, and Europe. In addition to several alterations of uncertain significance, we identified a homozygous alteration in the invariant G nucleotide of the RD3 exon 2 donor splice site in two siblings with Leber congenital amaurosis. This mutation is predicted to result in premature truncation of the RD3 protein, segregates with the disease, and is not detected in 121 ethnically matched control individuals. We suggest that the retinopathy-associated RD3 protein is part of subnuclear protein complexes involved in diverse processes, such as transcription and splicing.
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| 17. |
- Atwood, W. B., et al.
(författare)
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THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION
- 2009
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 697:2, s. 1071-1102
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Tidskriftsartikel (refereegranskat)abstract
- The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy gamma-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (4) localize point sources to 0.3-2 arcmin, (5) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (6) measure the diffuse isotropic gamma-ray background up to TeV energies, and (7) explore the discovery space for dark matter.
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| 18. |
- Balint-Kurti, Gabriel, et al.
(författare)
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Grid-Technology for Chemical Reactions Calculation (Computational Science – ICCS 2005)
- 2005
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Ingår i: Lecture Notes in Computer Science, Vol 3516: Computational Science – ICCS 2005, 5th International Conference, Atlanta, GA, USA, May 22-25, 2005, Proceedings, Part III (V.S. Sunderam, G.D. van Albada, J. Dongarra, editors). - Berlin/Heidelberg : SpringerLink. - 9783540260448 ; , s. 97-133
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- We discuss a possible strategy for implementing a grid-based approach to realizing the immense computational resources required to compute reactive molecular scattering cross sections and rate constants.
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| 19. |
- Bi, L. -H, et al.
(författare)
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Organo-ruthenium supported heteropolytungstates : synthesis, structure, electrochemistry, and oxidation catalysis
- 2009
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 48:21, s. 10068-10077
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Tidskriftsartikel (refereegranskat)abstract
- The reaction of [Ru(arene)Cl2]2 (arene = benzene, p-cymene) with [X2W22O74(OH)2] 12- (X = SbIII, BiIII) In buffer medium resulted In four organo-ruthenium supported heteropolytungstates, [Sb 2W20O70(RuC6H6) 2]10 (1), [Bi2W20O 70(RuC6H6)2]10- (2), [Sb2W20O7o(RuC10H14) 2]10- (3), and [Bi2W20O 70(RuC10H14)2]10- (4), which have been characterized in solution by multinuclear (183W, 13C, 1H) NMR, UV-vis spectroscopy, electrochemistry, and in the solid state by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis. Polyanions 1, 2, and 4 crystallize in the triclinic system, space group P1 with the following unit cell parameters: K5Na5[Sb2W20O 7o(RuC6H6)2]·22H 2O (KNa-1), a= 12.1625(2)Å, b = 13.1677(2) Å, C= 16.0141(3)Å α = 78.9201 (7)°, β = 74.4442(8)°, γ = 78.9019(8)°, and Z= 1 ; Cs2Na8[Bi2W 20O7o(RuC6H6)2] · 30H2O (CsNa-2), a = 11.6353(7) Å b = 13.3638(7) Å, C= 16.7067(8) Å, a = 79.568(2)°, β = 71.103(2)°, γ = 80.331(2)°, and Z= 1; Na10[Bi2W20O 70(RuC10H14)2]-35H20 (Na-4), a = 15.7376(12) Å b = 15.9806(13) Å, c = 24.2909(19) Å, α = 92.109(4)°, β = 101.354(4)°, γ = 97.365(3)°, and Z= 2. Polyanions 1-4 consist of two (L)Ru2+ (L = benzene or p-cymene) units linked to a [X2W20O70]14 (X=Sb III BiIII fragment via Ru-O(W) bonds resulting in an assembly with idealized C2h symmetry. Polyanions 1-4 are stable in solution as indicated by the expected 183W, 13C, and 1H NMR spectra. The electrochemistry of 1-4 is described by considering the reduction and the oxidation processes. The nature of the arene In Ru(arene) has practically no influence on the formal potentials of the W-centers, which are more sensitive to the Sb or Bi hetera atoms. The results suggest that the respective Sb- and Bi derivatives have very different pK a values, with the reduced form of 1 being the most basic, thus permitting the observation of two well-developed voltammetric waves at pH 6. In contrast, the identity of the arene influences the oxidation processes, thus permitting to distinguish them. A strong electrocatalytic water oxidation peak is observed that is more positive than the one corresponding to the Ru(arene) oxidation process. Also a stepwise oxidation of the Ru(benzene) group could be observed at pH 3. The catalytic efficiency, on the other hand, of 1-4 toward the oxidation of n-hexadecane and p-xylene illustrated the effect of ruthenium substitution on the polyanion catalytic performance.
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| 20. |
- Cornwell, William K., et al.
(författare)
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Plant species traits are the predominant control on litter decomposition rates within biomes worldwide
- 2008
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 11:10, s. 1065-1071
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Tidskriftsartikel (refereegranskat)abstract
- Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species-driven differences is much larger than previously thought and greater than climate-driven variation; (ii) the decomposability of a species' litter is consistently correlated with that species' ecological strategy within different ecosystems globally, representing a new connection between whole plant carbon strategy and biogeochemical cycling. This connection between plant strategies and decomposability is crucial for both understanding vegetation-soil feedbacks, and for improving forecasts of the global carbon cycle.
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