Inner southern magnetosphere observation of Mercury via SERENA ion sensors in BepiColombo mission.

Mercury's southern inner magnetosphere is an unexplored region as it was not observed by earlier space missions. In October 2021, BepiColombo mission has passed through this region during its first Mercury flyby. Here, we describe the observations of SERENA ion sensors nearby and inside Mercury's magnetosphere. An intermittent high-energy signal, possibly due to an interplanetary magnetic flux rope, has been observed downstream Mercury, together with low energy solar wind. Low energy ions, possibly due to satellite outgassing, were detected outside the magnetosphere. The dayside magnetopause and bow-shock crossing were much closer to the planet than expected, signature of a highly eroded magnetosphere. Different ion populations have been observed inside the magnetosphere, like low latitude boundary layer at magnetopause inbound and partial ring current at dawn close to the planet. These observations are important for understanding the weak magnetosphere behavior so close to the Sun, revealing details never reached before.

SERENA: Particle Instrument Suite for Determining the Sun-Mercury Interaction from BepiColombo.

The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase.

Electron-scale measurements of magnetic reconnection in space.

Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth's magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy; (ii) measured the electric field and current, which together cause the dissipation of magnetic energy; and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region.

Antimicrobial susceptibility, beta-lactamase and enterotoxin production in Bacillus cereus isolates from clinical and food samples.

The antimicrobial susceptibility of 30 clinical and 30 food Bacillus cereus isolates was determined. All isolates were susceptible to streptomycin, ciprofloxacin and gentamicin, 90 % of them to clindamycin and vancomycin, and 67 % to erythromycin. All isolates were resistant to amoxicillin with clavulanic acid, ampicillin, cefotaxime, ciprofloxacin, cloxacillin, cefotaxime with clavulanic acid and penicillin. The MIC values (determined by E-tests) were 48-256 mg/L for ampicillin, 0.19-1.5 mg/L for gentamicin, 0.125-1.0 mg/L for clindamycin, 0.047-4.0 mg/L for erythromycin and 1.5-16 mg/L for vancomycin. The MICs 4.6-18.75 g/L were observed for penicillin using the microdilution method. The presence of metallo-beta-lactamases was detected by E-test for 100 % of strains. Nonhemolytic diarrheal enterotoxin (NHE) was produced by 98.3 % of strains, while 31.7 % of them produced hemolytic diarrheal enterotoxin (HBL). Clinical isolates produced 10 % more HBL than food isolates. The psychrotrophic strains isolated from food samples produced NHE at 6.5 degrees C in 73 % of cases.