catena-Poly[[[aqua­(5-nitro­benzene-1,2,3-tricarboxyl­ato-κO 1)copper(II)]-di-μ-aqua-[diaqua­sodium]-di-μ-aqua] tetra­hydrate]

In the heteronuclear coordination polymer, {[CuNa(C9H2NO8)(H2O)7]·4H2O}n, the CuII atom is coordinated by six O atoms from five water mol­ecules and one 5-nitro­benzene-1,2,3-tricarboxyl­ate ligand in a slightly distorted octa­hedral geometry. The Na+ cation is surrounded by six water mol­ecules in an irregular trigonal-prismatic geometry. The Cu and Na atoms are connected by water bridges, forming an infinite chain. O—H⋯O hydrogen bonds involving the coordinated and uncoordinated water mol­ecules connect the chains into a three-dimensional network

Parton Distributions from Boosted Fields in the Coulomb Gauge

We propose a new method to calculate parton distribution functions (PDFs) from correlations of boosted quarks and gluons in the Coulomb gauge. Compared to the widely used quasi-PDFs defined from gauge-invariant Wilson-line operators, such correlations offer advantages including absence of linear power divergence, enhanced long-range precision, and accessibility to larger off-axis momenta. We verify the validity of this method at next-to-leading order in perturbation theory and use it to calculate the pion valence quark PDF on a lattice with spacing $a=0.06$ fm and valence pion mass $m_\pi=300$ MeV. Our result agrees with that from the gauge-invariant quasi-PDF at similar precision, achieved with only half the computational cost through a large off-axis momentum $|\vec{p}|\sim2.2$ GeV. This opens the door to a more efficient way to calculate parton physics on the lattice.Comment: 5 pages, 4 figures, and the appendi

White dwarf-main sequence binaries from LAMOST: the DR1 catalogue

Context. White dwarf-main sequence (WDMS) binaries are used to study several different important open problems in modern astrophysics. Aims. The Sloan Digital Sky Survey (SDSS) identified the largest catalogue of WDMS binaries currently known. However, this sample is seriously affected by selection effects and the population of systems containing cool white dwarfs and early-type companions is under-represented.Here we search for WDMS binaries within the spectroscopic data release 1 of the LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope) survey. LAMOST and SDSS follow different target selection algorithms. Hence, LAMOST WDMS binaries may be drawn from a different parent population and thus help in overcoming the selection effects incorporated by SDSS on the current observed population. Methods. We develop a fast and efficient routine based on the wavelet transform to identify LAMOST WDMS binaries containing a DA white dwarf and a M dwarf companion, and apply a decomposition/fitting routine to their LAMOST spectra to estimate their distances and measure their stellar parameters, namely the white dwarf effective temperatures, surface gravities and masses, and the secondary star spectral types. Results. We identify 121 LAMOST WDMS binaries, 80 of which are new discoveries, and estimate the sample to be \sim90 per cent complete. The LAMOST and SDSS WDMS binaries are found to be statistically different. However, this result is not due to the different target selection criteria of both surveys, but likely a simple consequence of the different observing conditions. Thus, the LAMOST population is found at considerably shorter distances (\sim50-450 pc) and is dominated by systems containing early-type companions and hot white dwarfs. (abridged)Comment: 14 pages, 8 figures, accepted for publication in A&

2-[5-(1,3-Benzodioxol-5-yl)-3-ferrocenyl-4,5-dihydro-1H-pyrazol-1-yl]-4-phenyl-1,3-thia­zole

In the title compound, [Fe(C5H5)(C24H18N3O2S)], the pyrazoline ring adopts a twist conformation. The thia­zole ring forms dihedral angles of 83.7 (2) and 34.4 (2)° with the benzene ring of the benzodioxole ring and the fused phenyl ring, respectively. The mol­ecular conformation is stabilized by an intra­molecular C—H⋯π inter­action. The crystal packing features inter­molecular C—H⋯N, C—H⋯O hydrogen bonds and weak C—H⋯π inter­actions

1-(4-tert-Butyl­benz­yl)-3-phenyl-1H-pyrazole-5-carboxylic acid

In the title compound, C21H22N2O2, the mean plane of the pyrazole ring makes dihedral angles of 18.80 (12) and 77.13 (5)°, respectively, with the mean planes of the phenyl and tert-butyl­benzyl rings. The carboxylate group is inclined at 8.51 (14)° with respect to the pyrazole ring. The crystal structure displays inter­molecular O—H⋯O hydrogen bonding, generating centrosymmetric dimers