An extreme magneto-ionic environment associated with the fast radio burst source FRB 121102.

Fast radio bursts are millisecond-duration, extragalactic radio flashes of unknown physical origin. The only known repeating fast radio burst source-FRB 121102-has been localized to a star-forming region in a dwarf galaxy at redshift 0.193 and is spatially coincident with a compact, persistent radio source. The origin of the bursts, the nature of the persistent source and the properties of the local environment are still unclear. Here we report observations of FRB 121102 that show almost 100 per cent linearly polarized emission at a very high and variable Faraday rotation measure in the source frame (varying from +1.46 × 105 radians per square metre to +1.33 × 105 radians per square metre at epochs separated by seven months) and narrow (below 30 microseconds) temporal structure. The large and variable rotation measure demonstrates that FRB 121102 is in an extreme and dynamic magneto-ionic environment, and the short durations of the bursts suggest a neutron star origin. Such large rotation measures have hitherto been observed only in the vicinities of massive black holes (larger than about 10,000 solar masses). Indeed, the properties of the persistent radio source are compatible with those of a low-luminosity, accreting massive black hole. The bursts may therefore come from a neutron star in such an environment or could be explained by other models, such as a highly magnetized wind nebula or supernova remnant surrounding a young neutron star.

Reversible, titrated deep sedation for major office surgery.

We have operated upon 446 consecutive patients in the office, using the controlled titrated method of sedation which we have described. We believe the results are superior to the methods in more common use. A major factor in choosing a narcotic as our one basic drug was the availability of a safe, swift, and effective antidote to it.

Cineholomicroscopy of small animal microcirculation.

A holomicrographic system capable of recording the dynamic microscopic events occurring in a living tissue has been developed. This paper discusses the system parameters, the basic configuration, and initial test results. The reconstructed real image from the hologram can be studied with a conventional microscope. The holographic system uses a collecting lens both in recording and in reconstructing. Test results reported include the dissolving of a gas bubble under increased pressure and the movement of polystyrene balls when ejected from a needle. Present resolution is greater than 3 micro, and object velocities greater than 25 mm sec(-1) can be recorded.