Implications of Fermi-LAT observations on the origin of IceCube neutrinos

The IceCube (IC) collaboration recently reported the detection of TeV-PeV extraterrestrial neutrinos whose origin is yet unknown. By the photon-neutrino connection in $pp$ and $p\gamma$ interactions, we use the \fermi-LAT observations to constrain the origin of the IC detected neutrinos. We find that Galactic origins, i.e., the diffuse Galactic neutrinos due to cosmic ray (CR) propagation in the Milky Way, and the neutrinos from the Galactic point sources, may not produce the IC neutrino flux, thus these neutrinos should be of extragalactic origin. Moreover, the extragalactic gamma-ray bursts (GRBs) may not account for the IC neutrino flux, the jets of active galactic nuclei may not produce the IC neutrino spectrum, but the starburst galaxies (SBGs) may be promising sources. As suggested by the consistency between the IC detected neutrino flux and the Waxman-Bahcall bound, GRBs in SBGs may be the sources of both the ultrahigh energy, $>10^{19}$eV, CRs and the $1-100$~PeV CRs that produce the IC detected TeV-PeV neutrinos.Comment: JCAP accepted version; 8 pages, 2 figs; discussion on blazar origin added; conclusion unchange

3-Phenyl-2-(1H-tetra­zol-1-yl)propanoic acid monohydrate

In the title compound, C10H10N4O2·H2O, the dihedral angle between the tetra­zole and benzene rings is 63.24 (11)°. The crystal structure is stabilized by intra­molecular O—H⋯N and O—H⋯O hydrogen bonds

Current rectification by asymmetric molecules: An ab initio study

We study current rectification effect in an asymmetric molecule HOOC-C$_6$H$_4$-(CH$_2$)$_n$ sandwiched between two Aluminum electrodes using an {\sl ab initio} nonequilibrium Green function method. The conductance of the system decreases exponentially with the increasing number $n$ of CH$_2$. The phenomenon of current rectification is observed such that a very small current appears at negative bias and a sharp negative differential resistance at a critical positive bias when $n\ge 2$. The rectification effect arises from the asymmetric structure of the molecule and the molecule-electrode couplings. A significant rectification ratio of $\sim$38 can be achieved when $n=5$.Comment: to appear in J. Chem. Phy

1-[Phen­yl(pyridin-2-yl­amino)­meth­yl]-2-naphthol

The title compound, C22H18N2O, was synthesized from naphthalen-2-ol, benzaldehyde and pyridin-2-amine. In the crystal, mol­ecules are linked into centrosymmetric R 2 2(16) dimers by pairs of O—H⋯N hydrogen bonds. The mol­ecular conformation is stabilized by an N—H⋯O hydrogen bond. The dihedral angle between the naphthylene ring system and the phenyl ring is 72.86 (12)°

catena-Poly[(triaqua­cadmium)-μ-5-hy­droxy­isophthalato-κ3 O 1,O 1′:O 3]

The title compound, [Cd(C8H4O5)(H2O)3]n, a one-dimensional chain complex of 5-hy­droxy­isophthalate with CdII, was prepared by a hydro­thermal reaction. The CdII ion is coordinated by three water O atoms and three carboxyl­ate O atoms of two different 5-hy­droxy­isophthalate ligands, which act as bidentate and monodentate ligands. The crystal structure is stabilized by O—H⋯O hydrogen bonds