36,163 research outputs found
Comparison of xenon triple point realizations
No full textIt is widely recognized that the Mercury triple point (MTP) being situated very close to the
Water triple point (WTP) constitutes a weakness in the International Temperature Scale
of 1990 (ITS-90), in addition to safety concerns related to the use and transportation of
Mercury. As such, a substitution for a safer, high-quality fixed point about half way between
the Argon and Water triple points would be highly desirable. Now, a direct comparison is
described of a Xenon cell filled in 2005 by the National Research Council Canada (NRC)
and a more recently produced cell of the Istituto Nazionale di Ricerca Metrologica (INRIM).
The present paper discusses the INRiM 2017 measurements on both the INRiM and NRC
cells, with a follow-up measurement at NRC, and presents the difference between the two
cells, (0.17 ± 0.08) mK with the uncertainties of each cell’s realization of the Xenon triple
point (XeTP), 0.11 mK for the INRiM cell and 0.07 mK for the NRC cell (k = 1). In addition,
the effect of substituting Mercury with Xenon on Type 1 non-uniqueness (‘SRI’, subrange
inconsistency), Type 3 non-uniqueness (‘NU3’, cSPRT variability) and propagation of fixed
point realization uncertainty is shown and discussed
The equation x^py^q=z^r and groups that act freely on \Lambda-trees
No full textLet be a finitely generated group that acts freely on a -tree, where is an ordered abelian group, and let be elements in . We show that if with integers , , , then , and commute
Solution, solid-state, and computational analysis of agostic interactions in a coherent set of low-coordinate rhodium(III) and iridium(III) complexes
No full textA homologous family of low-coordinate complexes of the formulation trans-[M(2,2′-biphenyl)(PR3)2][BArF4] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT 1H and 31P NMR spectroscopy) and solid-state (single crystal X-ray diffraction) data, and analysis in silico (DFT-based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the IrIII compared to RhIII complexes and, with respect to the phosphine ligands, in the order PiBu3>PCy3>PiPr3>PPh3. In addition to these structure–property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2-difluorobenzene vs. CH2Cl2) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M−H−C distances
Synthesis and properties of (+/-)-trans-([small eta]2-alkene)(4-alkyloxy-4[prime or minute]-stilbazole)dichloroplatinum: a remarkable family of low-melting metallomesogens
No full textA novel series of low-melting metallomesogens (metal-containing liquid crystals) has been prepared and characterised. Reaction of Zeise{'}s salt K[PtCl([small eta]-CH[double bond{,} length half m-dash]CH)] with the 4--alkyloxy-4[prime or minute]-stilbazole ligands (L = CHOCHCH[double bond{,} length half m-dash]CHCHN; = 3-12) yielded -[PtCl([small eta]-CH[double bond{,} length half m-dash]CH)L]{,} which react with alk-1-enes (CH[double bond{,} length half m-dash]CHCH; = 1-8{,} 10 or 12) to give -[PtCl(CH[double bond{,} length half m-dash]CHCH)L]. The complexes where ()[gt-or-equal] 8 are generally liquid crystalline (smectic A mesophases); those with shorter tails [()= 8 to 13] show monotropic mesophases{,} while those with longer tails [() > 13] show enantiotropic behaviour. The melting temperatures are lower than would be anticipated for metallomesogens of this size{,} reflecting the non-centrosymmetric molecular structures which make the crystal packing less easy. A 70 : 30 mixture of the complexes (= 12{,} = 3; K [rightward arrow] S at 61 [degree]C) and (= 12{,} = 6; K [rightward arrow] S at 70 [degree]C) shows the transition into the mesophase{,} K [rightward arrow] S{,} at 45 [degree]C{,} an unusually low temperature. The mesophase to isotropic (S[rightward arrow] I) transition temperatures remain rather constant at 92 +/- 4 [degree]C for all compositions
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C.
No full textDE MAIESTATE / PRAESIDE M. JACOBO THOMASIO, MORALIS PHILOSOPH. P. P., PUBLICE DISPUTABIT JOHANNES DUNTE, R. L. AUTHOR & RESPON: AD DIEM 9. SEPTEMBR. H L. Q. C.
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C. (1)
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Illuminaçao Apologetica do retrato de Morteçor en que aparecem com mais vivas côres os erros do author do novo Methodo, e seu Apologista ...
No full textFecha sacada de la pág.2 y 159Sign.: A-V\p4\sError tipográfico de signatura : a B\b2\s llama B\b3\
trans-(į2-Alkene)(4'-alkyloxy-4-stilbazole)dichloro-platinum; Low Melting Organometallic Mesogens
No full text-[PtCl(CHOCHCH[double bond{,} length half m-dash]CHCHN)([small eta]-CH[double bond{,} length half m-dash]CHCH)]() form stable smectic A mesophases on heating (for [gt-or-equal]7{,} [gt-or-equal]7; [gt-or-equal]8{,} [gt-or-equal]5; [gt-or-equal]9{,} [gt-or-equal]2; and [gt-or-equal]11{,} [gt-or-equal]0); melting temperatures below 50 [degree]C can easily be achieved
Convective–reactive nucleosynthesis of K, Sc, Cl and p-process isotopes in O–C shell mergers
No full text© 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. We address the deficiency of odd-Z elements P, Cl, K and Sc in Galactic chemical evolution models through an investigation of the nucleosynthesis of interacting convective O and C shells in massive stars. 3D hydrodynamic simulations of O-shell convection with moderate C-ingestion rates show no dramatic deviation from spherical symmetry. We derive a spherically averaged diffusion coefficient for 1D nucleosynthesis simulations, which show that such convective-reactive ingestion events can be a production site for P, Cl, K and Sc. An entrainment rate of 10-3M⊙s-1features overproduction factors OPs≈ 7. Full O-C shell mergers in our 1D stellar evolution massive star models have overproduction factors OPm> 1 dex but for such cases 3D hydrodynamic simulations suggest deviations from spherical symmetry. γ - process species can be produced with overproduction factors of OPm> 1 dex, for example, for130, 132Ba. Using the uncertain prediction of the 15M⊙, Z = 0.02 massive star model (OPm≈ 15) as representative for merger or entrainment convective-reactive events involving O- and C-burning shells, and assume that such events occur in more than 50 per cent of all stars, our chemical evolution models reproduce the observed Galactic trends of the odd-Z elements
Hundreds of variants clustered in genomic loci and biological pathways affect human height
No full textMost common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits(1), but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait(2,3). The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways
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