The cosmic ray shadow of the Moon observed with the ANTARES neutrino telescope

One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with 3.5 σ statistical significance. The detector angular resolution for downward-going muons is 0 . 73 ∘ ± 0 . 14 ∘ . The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location.

Acute motor axonal neuropathy with high titer IgG and IgA anti-GD1a antibodies following Campylobacter enteritis

We describe the first two European cases of acute axonal motor neuropathy with both IgG and IgA anti-GD1a antibodies following Campylobacter enteritis. Both patients acutely developed severe weakness without sensory involvement, had antibodies to Campylobacter jejuni and polyclonal IgG and IgA titers > or = 12,800 to GD1a at onset, which decreased during follow-up. Serial electrophysiologic studies showed: 1, normal or only slightly slowed motor conductions; 2, evidence of a progressive loss of excitability and conduction failure in nerve fibers undergoing axonal degeneration in intermediate nerve segments and evidence of distal axonal involvement in one nerve; 3, normal sensory conductions, sensory potential amplitudes and somatosensory evoked potentials. Although we cannot exclude that axonal degeneration followed demyelination, we think that anti-GD1a antibodies account for the axonal involvement because GD1a is present in the axolemma and exposed at the node of Ranvier and in nerve terminals. The exclusive motor involvement could be explained by the fact that GD1a has a different internal structure in motor and sensory fibers.