Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Ambient Fine Particulate Matter Induces Apoptosis of Endothelial Progenitor Cells Through Reactive Oxygen Species Formation

Background/Aims: Bone marrow (BM)-derived endothelial progenitor cells (EPCs) play a critical role in angiogenesis and vascular repair. Some environmental insults, like fine particulate matter (PM) exposure, significantly impair cardiovascular functions. However, the mechanisms for PM-induced adverse effects on cardiovascular system remain largely unknown. The present research was to study the detrimental effects of PM on EPCs and explore the potential mechanisms. Methods: PM was intranasal-distilled into male C57BL/6 mice for one month. Flow cytometry was used to measure the number of EPCs, apoptosis level of circulating EPCs and intracellular reactive oxygen species (ROS) formation. Serum TNF- α and IL-1β were measured using ELISA. To determine the role of PM-induced ROS in EPC apoptosis, PM was co-administrated with the antioxidant N-acetylcysteine (NAC) in wild type mice or used in a triple transgenic mouse line (TG) with overexpression of antioxidant enzyme network (AON) composed of superoxide dismutase (SOD)1, SOD3, and glutathione peroxidase (Gpx-1) with decreased in vivo ROS production. Results: PM treatment significantly decreased circulating EPC population, promoted apoptosis of EPCs in association with increased ROS production and serum TNF-α and IL-1β levels, which could be effectively reversed by either NAC treatment or overexpression of AON. Conclusion: PM exposure significantly decreased circulating EPCs population due to increased apoptosis via ROS formation in mice

Soil water storage compensation potential of herbaceous energy crops in semi-arid region

Large-scale vegetation construction has generally led to soil desiccation in arid and semi-arid regions. Energy crops with high biomass and water use efficiency are generally beneficial to agriculture and the environment. It is necessary to understand how to maintain the dynamic balance of soil moisture and biomass production on herbaceous energy croplands. In this study, soil moisture data at different depths of soil were obtained from long-term field observations for two energy crops, i.e., Panicum virgatum and Miscanthus sinensis, and a forage crop-Medicago saliva. Relative aridity of the soil and plant biomass were compared among different vegetation types, transects, and cultivation years. Medicago sativa soil was severely, even extremely, desiccative with increasing cultivation years, whereas there was nearly no desiccation in the soil of energy crops. The values of compared soil water storage compensation indexes in deep soil layers were higher than those in shallow soil layers, with the evaluated soil water storage compensation index being the smallest in the 40-80 cm layer. Energy crops had significantly higher aboveground biomass, mostly exhibiting more than 2.6 kg m(-2), while the aboveground biomass of M. saliva was only above 0.5 kg m(-2). Furthermore, the water use efficiencies of energy crops were obviously higher than that of M. saliva (P < 0.05). Our results indicated that deep soil moisture conditions were mainly determined by field crop types. Energy crops may be suitable candidates for compensating soil water storage and maintaining high biomass production in semi-arid regions

Nurse effects of patch-canopy microhabitats promote herbs community establishment in sandy land

Seedling establishment mostly occurs beneath the canopies of shrubs which act as nurse plants. Nurse effects of patch-canopy soil microhabitats on seedling establishment of herbs were investigated by studying shrub patches in which the nurse species Artemisia ordosica was removed or kept in a comparative way. The results showed that keeping shrubs greatly increased soil moisture and soil organic carbon content, but greatly decreased soil temperature and soil bulk density. The herbs richness and individual numbers in patches with the canopy kept were significantly higher than those with the canopy removed (p < 0.05). Small shrub patches increased soil moisture and decreased the surface soil temperature more significantly than large shrub patches. Herbs richness and individual numbers in small shrub patches were significantly higher than those in large shrub patches (p < 0.05). The results suggested that small shrub patches, which acted as nurse plants, decreased soil temperature and soil bulk density, increased soil moisture, species richness and individual numbers under the canopies. Nurse plants can provide a favourable surface habitats for herbs in semi-arid sandy lands

PM exposure significantly increased ROS production in BM cells.

<p>Intracellular ROS production was quantitatively determined using the ROS Detection Reagents-FITC in the bone marrow cells. Intracellular ROS formation was significantly increased in the bone marrow in the wild type mice with PM exposure. * PM vs PBS, P<0.001, n = 8.</p

PM treatment decreased murine BMSCs level without induction of apoptosis.

<p>After C57BL/6 mice were exposed to PM or PBS through intranasal distillation for 1 month, the BM cells were collected after treating with red blood cell lysis and stained with Lineage cocktail Pacific Blue, Sca-1 PE-Cy5 and CD133 PE antibody for flow-cytometry analysis for BMSCs as defined as lineage negative Sca-1 positive (LS) and Lineage negative CD133 positive (Lin^-/CD133⁺) cells. The BMSCs number was significantly decreased in C57BL/6 mice with PM exposure compared to the PBS control (A). Annexin V and PI were used to incubate the cells for apoptosis analysis. Both early and late apoptotic rates of cells in the mice with PM exposure were similar to the control PBS group (B). PBS: C57BL/6 mice with PBS treatment; PM: C57BL/6 mice with PM exposure. * PM vs PBS, P<0.01, n = 8.</p