Introduction The 2009 Family Smoking Prevention and Tobacco Control Act banned characterizing flavors other than menthol in cigarettes but did not restrict their use in other forms of tobacco (e.g., ...smokeless, cigars, hookah, e-cigarettes). Methods A cross-sectional analysis of Wave 1 data from 45,971 U.S. adults and youth, aged ≥12 years in the Population Assessment of Tobacco and Health (PATH) Study collected in 2013–2014, was conducted in 2016. This study examined (1) the prevalence and reasons for use of flavored tobacco products; (2) the proportion of ever tobacco users reporting that their first product was flavored; and (3) correlates of current flavored tobacco product use. Results Current flavored (including menthol) tobacco product use was highest in youth (80%, aged 12–17 years); and young adult tobacco users (73%, aged 18–24 years); and lowest in older adult tobacco users aged ≥65 years (29%). Flavor was a primary reason for using a given tobacco product, particularly among youth. Eighty-one percent of youth and 86% of young adult ever tobacco users reported that their first product was flavored versus 54% of adults aged ≥25 years. In multivariable models, reporting that one’s first tobacco product was flavored was associated with a 13% higher prevalence of current tobacco use among youth ever tobacco users and a 32% higher prevalence of current tobacco use among adult ever users. Conclusions These results add to the evidence base that flavored tobacco products may attract young users and serve as starter products to regular tobacco use.
Voyager 1 crossed the termination shock of the supersonic flow of the solar wind on 16 December 2004 at a distance of 94.01 astronomical units from the Sun, becoming the first spacecraft to begin ...exploring the heliosheath, the outermost layer of the heliosphere. The shock is a steady source of low-energy protons with an energy spectrum$\sim E^{-1.41 \pm 0.15}$from$0.5 to \sim 3.5 megaelectron volts$, consistent with a weak termination shock having a solar wind velocity jump ratio$r = 2.6_{-0.2}^{+0.4}$. However, in contradiction to many predictions, the intensity of anomalous cosmic ray (ACR) helium did not peak at the shock, indicating that the ACR source is not in the shock region local to Voyager 1. The intensities of ~10-megaelectron volt electrons, ACRs, and galactic cosmic rays have steadily increased since late 2004 as the effects of solar modulation have decreased.
The Integrated Science Investigation of the Sun (ISIS) is a complete science investigation on the Solar Probe Plus (SPP) mission, which flies to within nine solar radii of the Sun’s surface. ISIS ...comprises a two-instrument suite to measure energetic particles over a very broad energy range, as well as coordinated management, science operations, data processing, and scientific analysis. Together, ISIS observations allow us to explore the mechanisms of energetic particles dynamics, including their: (1) Origins—defining the seed populations and physical conditions necessary for energetic particle acceleration; (2) Acceleration—determining the roles of shocks, reconnection, waves, and turbulence in accelerating energetic particles; and (3) Transport—revealing how energetic particles propagate from the corona out into the heliosphere. The two ISIS Energetic Particle Instruments measure lower (EPI-Lo) and higher (EPI-Hi) energy particles. EPI-Lo measures ions and ion composition from ∼20 keV/nucleon–15 MeV total energy and electrons from ∼25–1000 keV. EPI-Hi measures ions from ∼1–200 MeV/nucleon and electrons from ∼0.5–6 MeV. EPI-Lo comprises 80 tiny apertures with fields-of-view (FOVs) that sample over nearly a complete hemisphere, while EPI-Hi combines three telescopes that together provide five large-FOV apertures. ISIS observes continuously inside of 0.25 AU with a high data collection rate and burst data (EPI-Lo) coordinated with the rest of the SPP payload; outside of 0.25 AU, ISIS runs in low-rate science mode whenever feasible to capture as complete a record as possible of the solar energetic particle environment and provide calibration and continuity for measurements closer in to the Sun. The ISIS Science Operations Center plans and executes commanding, receives and analyzes all ISIS data, and coordinates science observations and analyses with the rest of the SPP science investigations. Together, ISIS’ unique observations on SPP will enable the discovery, untangling, and understanding of the important physical processes that govern energetic particles in the innermost regions of our heliosphere, for the first time. This paper summarizes the ISIS investigation at the time of the SPP mission Preliminary Design Review in January 2014.
Although the average composition of solar energetic particles (SEPs) and the bulk solar wind are similar in a number of ways, there are key differences which imply that solar wind is not the ...principal seed population for SEPs accelerated by coronal mass ejection (CME) driven shocks. This paper reviews these composition differences and considers the composition of other possible seed populations, including coronal material, impulsive flare material, and interplanetary CME material.
We report improved measurements of elemental abundances and spectra for galactic cosmic-ray (GCR) nuclei obtained by the Cosmic Ray Isotope Spectrometer on board NASA's Advanced Composition Explorer ...(ACE) spacecraft during the minimum and maximum phases of solar cycle 23. We discuss results for particles with nuclear charge 5 <= Z <= 28 and typical energies between 50 and 500 MeV nucleon-1. We demonstrate that a detailed 'leaky box' Galactic propagation model combined with a spherically symmetric solar modulation model gives a good (but not perfect) fit to the observed spectra by using a solar modulation parameter of = 325 MV at solar minimum and = 900 MV at solar maximum. Although our results are generally consistent with previous measurements from space-based and balloon-based missions, there are significant differences. The large geometrical acceptance and excellent charge resolution of the instrument result in the most detailed and statistically significant record of GCR composition to date in this energy range. The measurements reported here serve as a high-precision baseline for continued studies of GCR composition, solar modulation over the solar cycle, space radiation hazards, and other applications.
The Low-Energy Telescope (LET) is one of four sensors that make up the Solar Energetic Particle (SEP) instrument of the IMPACT investigation for NASA’s STEREO mission. The LET is designed to measure ...the elemental composition, energy spectra, angular distributions, and arrival times of H to Ni ions over the energy range from ∼3 to ∼30 MeV/nucleon. It will also identify the rare isotope
3
He and trans-iron nuclei with 30≤
Z
≤83. The SEP measurements from the two STEREO spacecraft will be combined with data from ACE and other 1-AU spacecraft to provide multipoint investigations of the energetic particles that result from interplanetary shocks driven by coronal mass ejections (CMEs) and from solar flare events. The multipoint in situ observations of SEPs and solar-wind plasma will complement STEREO images of CMEs in order to investigate their role in space weather. Each LET instrument includes a sensor system made up of an array of 14 solid-state detectors composed of 54 segments that are individually analyzed by custom Pulse Height Analysis System Integrated Circuits (PHASICs). The signals from four PHASIC chips in each LET are used by a Minimal Instruction Set Computer (MISC) to provide onboard particle identification of a dozen species in ∼12 energy intervals at event rates of ∼1,000 events/sec. An additional control unit, called SEP Central, gathers data from the four SEP sensors, controls the SEP bias supply, and manages the interfaces to the sensors and the SEP interface to the Instrument Data Processing Unit (IDPU). This article outlines the scientific objectives that LET will address, describes the design and operation of LET and the SEP Central electronics, and discusses the data products that will result.
The Parker Solar Probe was launched on 2018 August 12 and completed its second orbit on 2019 June 19 with perihelion of 35.7 solar radii. During this time, the Energetic Particle Instrument-Hi ...(EPI-Hi, one of the two energetic particle instruments comprising the Integrated Science Investigation of the Sun, IS IS) measured seven proton intensity increases associated with stream interaction regions (SIRs), two of which appear to be occurring in the same region corotating with the Sun. The events are relatively weak, with observed proton spectra extending to only a few MeV and lasting for a few days. The proton spectra are best characterized by power laws with indices ranging from −4.3 to −6.5, generally softer than events associated with SIRs observed at 1 au and beyond. Helium spectra were also obtained with similar indices, allowing He/H abundance ratios to be calculated for each event. We find values of 0.016-0.031, which are consistent with ratios obtained previously for corotating interaction region events with fast solar wind ≤600 km s−1. Using the observed solar wind data combined with solar wind simulations, we study the solar wind structures associated with these events and identify additional spacecraft near 1 au appropriately positioned to observe the same structures after some corotation. Examination of the energetic particle observations from these spacecraft yields two events that may correspond to the energetic particle increases seen by EPI-Hi earlier.
Abstract
The Cosmic Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer spacecraft has been operating successfully in a halo orbit about the L1 Lagrange point since late 1997. We ...report here the isotopic composition of the Galactic cosmic ray (GCR) elements with 29 ≤
Z
≤ 38 derived from more than 20 years of CRIS data. Using a model of cosmic-ray transport in the Galaxy and the solar system (SS), we have derived from these observations the isotopic composition of the accelerated material at the GCR source (GCRS). Comparison of the isotopic fractions of these elements in the GCRS with corresponding fractions in the solar system gives no indication of GCRS enrichment in
r
-process isotopes. Since a large fraction of core-collapse supernovae (CCSNe) occur in OB associations, the fact that GCRs do not contain enhanced abundances of
r
-process nuclides indicates that CCSNe are not the principal source of lighter (
Z
≤ 38)
r
-process nuclides in the solar system. This conclusion supports recent work that points to binary neutron-star mergers, rather than supernovae, as the principal source of galactic
r
-process isotopes.
A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (IS IS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of ...0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly close to the source. The event was very small, with peak 1 MeV proton intensities of ∼0.3 particles (cm2 sr s MeV)−1, and was undetectable above background levels at energies above 10 MeV or in particle detectors at 1 au. It was strongly anisotropic, with intensities flowing outward from the Sun up to 30 times greater than those flowing inward persisting throughout the event. Temporal association between particle increases and small brightness surges in the extreme-ultraviolet observed by the Solar TErrestrial RElations Observatory, which were also accompanied by type III radio emission seen by the Electromagnetic Fields Investigation on PSP, indicates that the source of this event was an active region nearly 80° east of the nominal PSP magnetic footpoint. This suggests that the field lines expanded over a wide longitudinal range between the active region in the photosphere and the corona.
Summary
Background
Thiopurines (azathioprine and mercaptopurine) remain integral to most medical strategies for maintaining remission in Crohn's disease (CD) and ulcerative colitis (UC). Indefinite ...use of these drugs is tempered by long‐term risks. While clinical relapse is noted frequently following drug withdrawal, there are few published data on predictive factors.
Aim
To investigate the success of planned thiopurine withdrawal in patients in sustained clinical remission to identify rates and predictors of relapse.
Methods
This was a multicentre retrospective cohort study from 11 centres across the UK. Patients included had a definitive diagnosis of IBD, continuous thiopurine use ≥3 years and withdrawal when in sustained clinical remission. All patients had a minimum of 12 months follow‐up post drug withdrawal. Primary and secondary end points were relapse at 12 and 24 months respectively.
Results
237 patients were included in the study (129 CD; 108 UC). Median duration of thiopurine use prior to withdrawal was 6.0 years (interquartile range 4.4–8.4). At follow‐up, moderate/severe relapse was observed in 23% CD and 12% UC patients at 12 months, 39% CD and 26% UC at 24 months. Relapse rate at 12 months was significantly higher in CD than UC (P = 0.035).
Elevated CRP at withdrawal was associated with higher relapse rates at 12 months for CD (P = 0.005), while an elevated white cell count was predictive at 12 months for UC (P = 0.007).
Conclusion
Thiopurine withdrawal in the context of sustained remission is associated with a 1‐year moderate‐to‐severe relapse rate of 23% in Crohn's disease and 12% in ulcerative colitis.
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