Simulated Performance of 3-DTI Gamma-Ray Telescope Concepts

We present Monte Carlo simulations of two astronomical gamma-ray telescope concepts based on the ThreeDimensional Track Imager (3- DTI) detector. The 3-DTI consists of a time projection chamber with two-dimensional, crossedstrip micro-well detector readout. The full three- dimensional reconstruction of charged-particle tracks in the gas volume is obtained from transient digitizers, which record the time signature of the charge collected in the wells of each strip. Such detectors hold great promise for advanced Compton telescope (ACT) and advanced pair telescope (APT) concepts due to the very precise measurement of charged particle momenta that is possible (Compton recoil electrons and electron-positron pairs, respectively). We have investigated the performance of baseline ACT and APT designs based on the 3-DTI detector using simulation tools based on GEANT3 and GEANT4, respectively. We present the expected imaging, spectroscopy, polarimetry, and background performance of each design

Medium-Energy Gamma-Ray Astrophysics with the 3-DTI Gamma-Ray Telescope

Gamma-ray observations in the medium energy range (0.50-50.0 MeV) are central to unfolding many outstanding questions in astrophysics. The challenges of medium-energy gamma-ray observations, however, are the low photon statistics and large backgrounds. We review these questions, address the telescope technology requirements, and describe our development of the 3-Dimensional Track Imaging (3-DTI) Compton telescope and its performance for a new mediumenergy gamma-ray mission. The 3-DTI is a large-volume time projection chamber (TPC) with a 2-dimensional gas micro-well detector (MWD) readout

Factors Associated with Adherence to the Mediterranean Diet among Adolescents Living in Sicily, Southern Italy

The present study aimed to examine the factors associated with increased Mediterranean diet (MD) adherence among a sample of Italian adolescents. A cross-sectional survey was conducted on 1135 students (13–16 years) attending 13 secondary schools of Sicily, southern Italy. Validated instruments were used for dietary assessment and the KIDMED score to assess adolescents’ adherence to the MD. A higher adherence to the MD was associated with high socioeconomic status (Odds Ratio [OR] 1.53, 95% Confidence Interval [CI]: 1.03–2.26) and high physical activity (OR 1.19, 95% CI: 1.02–1.70), whereas lower adherence was associated with living in an urban environment (OR 0.65, 95% CI: 0.44–0.97) and being obese (OR 0.59, 95% CI: 0.37–0.94). The adolescents’ KIDMED scores were inversely associated with adolescents’ intake of sweets, fast foods, fried foods, and sugary drinks, and directly with fruit, vegetables, pasta, fish, and cheese intakes. Urban-living adolescents were less likely to eat fruit and more prone to consume meat, sugary drinks, and fast food than rural-living adolescents. The latter were more likely to eat sweets and snacks. A general poor quality of food consumption in Italian adolescents away from the MD was reported, especially among those living in urban areas

A measurement of cosmic ray deuterium from 0.5–2.9 GeV/nucleon

The rare isotopes ^(2)H and ^(3)He in cosmic rays are believed to originate mainly from the interaction of high energy protons and helium with the galactic interstellar medium. The unique propagation history of these rare isotopes provides important constraints on galactic cosmic ray source spectra and on models for their propagation within the Galaxy. Hydrogen and helium isotopes were measured with the balloon-borne experiment, IMAX, which flew from Lynn Lake, Manitoba in 1992. The energy spectrum of deuterium between 0.5 and 3.2 GeV/nucleon measured by the IMAX experiment as well as previously published results of ^(3)He from the same instrument will be compared with predictions of cosmic ray galactic propagation models. The observed composition of the light isotopes is found to be generally consistent with the predictions of the standard Leaky Box Model derived to fit observations of heavier nucle

Social disparities, health risk behaviors, and cancer

Background: Overall cancer incidence rates decreased in the most recent time period in both men and women, largely due to improvements in surgical therapeutic approaches (tertiary prevention) and screening programs (secondary prevention), but differences in cancer incidence and survival according to socioeconomic status are documented worldwide. Health risk behaviors, defined as habits or practices that increase an individual’s likelihood of harmful health outcomes, are thought to mediate such inequalities. Discussion: Obesity has been related with increased cancer incidence and mortality due to imbalance of leptin and adiponectin which are connected to activation of PI3K, MAPK, and STAT3 pathways and decreasing insulin/insulin-like growth factor (IGF)-1 and mTOR signaling via activation of 5 AMP-activated protein kinase (AMPK), respectively. Physical activity has been associated to prevent cancer by the aforementioned obesity-related mechanisms, but also increasing level of circulating vitamin D, which has been related to lower risk of several cancers, and increasing prostaglandin F2a and reducing prostaglandin E2, which are both related with cancer prevention and promotion, respectively. A large number of different substances may induce themselves a direct cytotoxicity and mutagenic action on cells by smoking, whereas alcohol promote immune suppression, the delay of DNA repair, inhibition of the detoxification of carcinogens, the production of acetaldehyde, and the contribution to abnormal DNA methylation. The combined smoking and alcohol drinking habits have been shown to increase cancer risk by smoke action of increasing the acetaldehyde burden following alcohol consumption and alcohol action of enhancing the activation of various procarcinogens contained in tobacco smoke. Conclusions: Interventions at the social level may be done to increase awareness about cancer risks and promote changing in unhealthy behaviors

Ultra-heavy cosmic-ray science--Are r-process nuclei in the cosmic rays produced in supernovae or binary neutron star mergers?

The recent detection of 60Fe in the cosmic rays provides conclusive evidence that there is a recently synthesized component (few MY) in the GCRs (Binns et al. 2016). In addition, these nuclei must have been synthesized and accelerated in supernovae near the solar system, probably in the Sco-Cen OB association subgroups, which are about 100 pc distant from the Sun. Recent theoretical work on the production of r-process nuclei appears to indicate that it is difficult for SNe to produce the solar system abundances relative to iron of r-process elements with high atomic number (Z), including the actinides (Th, U, Np, Pu, and Cm). Instead, it is believed by many that the heaviest r-process nuclei, or perhaps even all r-process nuclei, are produced in binary neutron star mergers. Since we now know that there is at least a component of the GCRs that has been recently synthesized and accelerated, models of r-process production by SNe and BNSM can be tested by measuring the relative abundances of these ultra-heavy r-process nuclei, and especially the actinides, since they are radioactive and provide clocks that give the time interval from nucleosynthesis to detection at Earth. Since BNSM are believed to be much less frequent in our galaxy than SNe (roughly 1000 times less frequent, the ratios of the actinides, each with their own half-life, will enable a clear determination of whether the heaviest r-process nuclei are synthesized in SNe or in BNSM. In addition, the r-process nuclei for the charge range from 34 to 82 can be used to constrain models of r-process production in BNSM and SNe. Thus, GCRs become a multi-messenger component in the study of BNSM and SNe.Comment: Astro2020 Science White Pape

ISOMAX: Flight Performance of the Isotope Magnet Experiment

ISOMAX, a new balloon-borne cosmic ray instrument developed to measure the isotopic composition of the light elements in the cosmic radiation, was flown for the first time on August 4-5, 1998, from Lynn Lake, Manitoba, Canada. The main purpose of the ISOMAX program is to obtain the ratio of radioactive 10Be to stable 9Be over a wide range of energies, and consequently a wide range of time-dilation factors. Configured for its first flight, ISOMAX has a geometry factor of 450 cm^2sr and uses a large, high-field, superconducting magnet in conjunction with state-of-the-art tracking, time-of-flight, and Cherenkov detectors to measure light isotopes with a mass resolution better than 0.25 amu over the ~0.2-1.7 Ge V /nucleon energy range. In the 1998 flight, the maximum detectable rigidity of the ISO MAX magnetic spectrometer was 970 GV/c for He at 60% of the full magnetic field. ISOMAX returned over 16 hours of data from altitudes of more than 36 km as well as considerable data from lower altitudes. In this paper, a description of the instrument and initial isotopic results will be presented. The performance and results from the individual detector systems are discussed in other papers presented at this meeting

On-orbit Operations and Offline Data Processing of CALET onboard the ISS

The CALorimetric Electron Telescope (CALET), launched for installation on the International Space Station (ISS) in August, 2015, has been accumulating scientific data since October, 2015. CALET is intended to perform long-duration observations of high-energy cosmic rays onboard the ISS. CALET directly measures the cosmic-ray electron spectrum in the energy range of 1 GeV to 20 TeV with a 2% energy resolution above 30 GeV. In addition, the instrument can measure the spectrum of gamma rays well into the TeV range, and the spectra of protons and nuclei up to a PeV. In order to operate the CALET onboard ISS, JAXA Ground Support Equipment (JAXA-GSE) and the Waseda CALET Operations Center (WCOC) have been established. Scientific operations using CALET are planned at WCOC, taking into account orbital variations of geomagnetic rigidity cutoff. Scheduled command sequences are used to control the CALET observation modes on orbit. Calibration data acquisition by, for example, recording pedestal and penetrating particle events, a low-energy electron trigger mode operating at high geomagnetic latitude, a low-energy gamma-ray trigger mode operating at low geomagnetic latitude, and an ultra heavy trigger mode, are scheduled around the ISS orbit while maintaining maximum exposure to high-energy electrons and other high-energy shower events by always having the high-energy trigger mode active. The WCOC also prepares and distributes CALET flight data to collaborators in Italy and the United States. As of August 31, 2017, the total observation time is 689 days with a live time fraction of the total time of approximately 84%. Nearly 450 million events are collected with a high-energy (E>10 GeV) trigger. By combining all operation modes with the excellent-quality on-orbit data collected thus far, it is expected that a five-year observation period will provide a wealth of new and interesting results.Comment: 11 pages, 7 figures, published online 27 February 201