PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy

The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which extends previously published measurements down to 60 MeV and up to 180 GeV in kinetic energy. During 850 days of data acquisition approximately 1500 antiprotons were observed. The measurements are consistent with purely secondary production of antiprotons in the galaxy. More precise secondary production models are required for a complete interpretation of the results.Comment: 11 pages, 3 figures, 1 table. Accepted for publication in Physical Review Letter

Disturbance of the gut microbiota in early-life selectively affects visceral pain in adulthood without impacting cognitive or anxiety-related behaviors in male rats.

Disruption of bacterial colonization during the early postnatal period is increasingly being linked to adverse health outcomes. Indeed, there is a growing appreciation that the gut microbiota plays a role in neurodevelopment. However, there is a paucity of information on the consequences of early-life manipulations of the gut microbiota on behavior. To this end we administered an antibiotic (vancomycin) from postnatal days 4-13 to male rat pups and assessed behavioral and physiological measures across all aspects of the brain-gut axis. In addition, we sought to confirm and expand the effects of early-life antibiotic treatment using a different antibiotic strategy (a cocktail of pimaricin, bacitracin, neomycin; orally) during the same time period in both female and male rat pups. Vancomycin significantly altered the microbiota, which was restored to control levels by 8 weeks of age. Notably, vancomycin-treated animals displayed visceral hypersensitivity in adulthood without any significant effect on anxiety responses as assessed in the elevated plus maze or open field tests. Moreover, cognitive performance in the Morris water maze was not affected by early-life dysbiosis. Immune and stress-related physiological responses were equally unaffected. The early-life antibiotic-induced visceral hypersensitivity was also observed in male rats given the antibiotic cocktail. Both treatments did not alter visceral pain perception in female rats. Changes in visceral pain perception in males were paralleled by distinct decreases in the transient receptor potential cation channel subfamily V member 1, the α-2A adrenergic receptor and cholecystokinin B receptor. In conclusion, a temporary disruption of the gut microbiota in early-life results in very specific and long-lasting changes in visceral sensitivity in male rats, a hallmark of stress-related functional disorders of the brain-gut axis such as irritable bowel disorder

Disturbance of the gut microbiota in early-life selectively affects visceral pain in adulthood without impacting cognitive or anxiety-related behaviors in male rats.

Disruption of bacterial colonization during the early postnatal period is increasingly being linked to adverse health outcomes. Indeed, there is a growing appreciation that the gut microbiota plays a role in neurodevelopment. However, there is a paucity of information on the consequences of early-life manipulations of the gut microbiota on behavior. To this end we administered an antibiotic (vancomycin) from postnatal days 4-13 to male rat pups and assessed behavioral and physiological measures across all aspects of the brain-gut axis. In addition, we sought to confirm and expand the effects of early-life antibiotic treatment using a different antibiotic strategy (a cocktail of pimaricin, bacitracin, neomycin; orally) during the same time period in both female and male rat pups. Vancomycin significantly altered the microbiota, which was restored to control levels by 8 weeks of age. Notably, vancomycin-treated animals displayed visceral hypersensitivity in adulthood without any significant effect on anxiety responses as assessed in the elevated plus maze or open field tests. Moreover, cognitive performance in the Morris water maze was not affected by early-life dysbiosis. Immune and stress-related physiological responses were equally unaffected. The early-life antibiotic-induced visceral hypersensitivity was also observed in male rats given the antibiotic cocktail. Both treatments did not alter visceral pain perception in female rats. Changes in visceral pain perception in males were paralleled by distinct decreases in the transient receptor potential cation channel subfamily V member 1, the α-2A adrenergic receptor and cholecystokinin B receptor. In conclusion, a temporary disruption of the gut microbiota in early-life results in very specific and long-lasting changes in visceral sensitivity in male rats, a hallmark of stress-related functional disorders of the brain-gut axis such as irritable bowel disorder

CALET UPPER LIMITS on X-RAY and GAMMA-RAY COUNTERPARTS of GW151226

We present upper limits in the hard X-ray and gamma-ray bands at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) gravitational-wave event GW151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ~1 GeV up to 10 TeV with a field of view of ~2 sr. The CALET gamma-ray burst monitor (CGBM) views ~3 sr and ~2π sr of the sky in the 7 keV–1 MeV and the 40 keV–20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW151226 sky localization probability in the 7 keV–1 MeV and 40 keV–20 MeV bands respectively. We place a 90% upper limit of 2 × 10−7 erg cm−2 s−1 in the 1–100 GeV band where CAL reaches 15% of the integrated LIGO probability (~1.1 sr). The CGBM 7σ upper limits are 1.0 × 10−6 erg cm−2 s−1 (7–500 keV) and 1.8 × 10−6 erg cm−2 s−1 (50–1000 keV) for a 1 s exposure. Those upper limits correspond to the luminosity of 3–5 × 1049 erg s−1, which is significantly lower than typical short GRBs

Evidence of Energy and Charge Sign Dependence of the Recovery Time for the 2006 December Forbush Event Measured by the PAMELA Experiment

New results on the short-term galactic cosmic ray (GCR) intensity variation (Forbush decrease) in December 2006 measured by the PAMELA instrument are presented. Forbush decreases are sudden suppressions of the GCR intensities which are associated with the passage of interplanetary transients such as shocks and interplanetary coronal mass ejections (ICMEs). Most of the past measurements of this phenomenon were carried out with ground-based detectors such as neutron monitors or muon telescopes. These techniques allow only the indirect detection of the overall GCR intensity over an integrated energy range. For the first time, thanks to the unique features of the PAMELA magnetic spectrometer, the Forbush decrease commencing on 2006 December 14, following a CME at the Sun on 2006 December 13 was studied in a wide rigidity range (0.4 - 20 GV) and for different species of GCRs detected directly in space. The daily averaged GCR proton intensity was used to investigate the rigidity dependence of the amplitude and the recovery time of the Forbush decrease. Additionally, for the first time, the temporal variations in the helium and electron intensities during a Forbush decrease were studied. Interestingly, the temporal evolutions of the helium and proton intensities during the Forbush decrease were found in good agreement, while the low rigidity electrons (< 2 GV) displayed a faster recovery. This difference in the electron recovery is interpreted as a charge-sign dependence introduced by drift motions experienced by the GCRs during their propagation through the heliosphere