Modelling environmental niche for the endangered freshwater crayfish species Austopotamobius pallipes complex in Northern and Central Italy

The potential distribution of endangered species is a necessary step to assess species conservation status and manage reintroduction plans. In the context of the Life project CRAINat (LIFE+ 08 NAT/IT/000352) on the endangered Austropotamobius pallipes complex, we modelled the environmental niche of the species in two large areas of Northern (Lombardy, 43 records) and Central Italy (Abruzzo, Province of Isernia, Gran Sasso e Monti della Laga National Park; 69 records). Suitability models were built by using the maximum entropy approach as implemented in the MaxEnt software (vers. 3.3), which predict the occurrence of a species using presence-only data. The occurrence of A. pallipes was modelled using six variables: altitude, slope, aspect, anthropic disturbance (3 classes derived from Corine Land Cover), mean temperature of warmest quarter (from www.worldclim.org) and distance from stream system (as control variable accounting for small streams not solved in the digital map of rivers within studied areas). Each study area was modelled independently. Both potential distribution obtained high performance scores as measured by the AUC index (N-Italy: 0.92; C-Italy: 0.88). In both areas, altitude, slope and distance achieved the greatest predictive power. Moreover, in C-Italy the mean temperature of warmest quarter was also signifi cant in predicting species occurrence. The white-clawed crayfi sh prefer habitat next to stream system and with low slope; in N-Italy the species select the altitude interval of 400-600 m, while in the C-Italy it occur preferentially within 800-1200 m, due to the increase of temperature

High-resolution hypernuclear spectroscopy at Jefferson Lab, Hall A

International audienceThe experiment E94-107 in Hall A at Jefferson Lab started a systematic study of high-resolution hypernuclear spectroscopy in the 0p-shell region of nuclei such as the hypernuclei produced in electroproduction on Be9,C12, and O16 targets. In order to increase counting rates and provide unambiguous kaon identification, two superconducting septum magnets and a ring-imaging Cherenkov detector were added to the Hall A standard equipment. The high-quality beam, the good spectrometers, and the new experimental devices allowed us to obtain very good results. For the first time, measurable strength with sub-MeV energy resolution was observed for the core-excited states of BΛ12. A high-quality NΛ16 hypernuclear spectrum was likewise obtained. A first measurement of the Λ binding energy for NΛ16, calibrated against the elementary reaction on hydrogen, was obtained with high precision, 13.76±0.16 MeV. Similarly, the first LiΛ9 hypernuclear spectrum shows general agreement with theory (distorted-wave impulse approximation with the SLA and BS3 electroproduction models and shell-model wave functions). Some disagreement exists with respect to the relative strength of the states making up the first multiplet. A Λ separation energy of 8.36 MeV was obtained, in agreement with previous results. It has been shown that the electroproduction of hypernuclei can provide information complementary to that obtained with hadronic probes and the γ-ray spectroscopy technique

Detection of Galactic and Extragalactic Millimeter-wavelength Transient Sources with SPT-3G

International audienceHigh angular resolution cosmic microwave background experiments provide a unique opportunity to conduct a survey of time-variable sources at millimeter wavelengths, a population that has primarily been understood through follow-up measurements of detections in other bands. Here we report the first results of an astronomical transient survey with the South Pole Telescope (SPT) using the SPT-3G camera to observe 1500 deg2 of the southern sky. The observations took place from 2020 March to November in three bands centered at 95, 150, and 220 GHz. This survey yielded the detection of 15 transient events from sources not previously detected by the SPT. The majority are associated with variable stars of different types, expanding the number of such detected flares by more than a factor of two. The stellar flares are unpolarized and bright, in some cases exceeding 1 Jy, and have durations from a few minutes to several hours. Another population of detected events last for 2–3 weeks and appear to be extragalactic in origin. Though data availability at other wavelengths is limited, we find evidence for concurrent optical activity for two of the stellar flares. Future data from SPT-3G and forthcoming instruments will provide real-time detection of millimeter-wave transients on timescales of minutes to months