45 research outputs found
Combined pre-supernova alert system with KamLAND and Super-Kamiokande
Preceding a core-collapse supernova (CCSN), various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande (SK) via inverse beta decay interactions. Once these pre-supernova (pre-SN) neutrinos are observed, an early warning of the upcoming CCSN can be provided. In light of this, KamLAND and SK, both located in the Kamioka mine in Japan, have been monitoring pre-SN neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and SK on pre-SN neutrino detection. A pre-SN alert system combining the KamLAND detector and the SK detector was developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-SN neutrino signal from a 15 M⊙ star within 510 pc of the Earth at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hr in advance
Rising rural body-mass index is the main driver of the global obesity epidemic in adults
Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)
Rotational Relaxation Analysis and Simulation of REMPI Spectra for Molecule Nitrogen
The new DLR-High Vacuum Test Facility STG enables an experimental investigation of typical thruster plumes as prerequisite to determine disturbance effects of thruster firing like e.g. perturbing forces and moments, excessive heat loads, and contamination. Its main feature, a large liquid helium-driven cryopump allows the undisturbed plume gas expansion into the highly rarefied regime including the backflow. Because of the very low number densities in these regions, as an appropriate measurement technique the highly sensitive spectroscopie method REMPI (Resonance Enhanced Multi-Photon Ionization) is applied to obtain multiphoton spectra. This method delivers a precise determination of the most important plume flow characteristics, namely the temperature, the density, and gas velocity. In the first part of this study, the analytical technique of Gallagher and Fenn [?] is used to determine the characteristic rotational relaxation rate for nitrogen. The rates will then be discussed with those obtained by other methods. Further, a comparison between the experimental rotational temperature data measured in the STG and the analytical results will be carried out. In the second part, the simulation of the REMPI spectra is extended to consider the broadening of each absorption line including Doppler and collision broadening