526 research outputs found

    Energetic charged particle fluxes relevant to Ganymede's polar region

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    The JEDI instrument made measurements of energetic charged particles near Ganymede during a close encounter with that moon. Here we find ion flux levels are similar close to Ganymede itself but outside its magnetosphere and on near wake and open field lines. But energetic electron flux levels are more than a factor of 2 lower on polar and near-wake field lines than on nearby Jovian field lines at all energies reported here. Flux levels are relevant to the weathering of the surface, particularly processes that affect the distribution of ice, since surface brightness has been linked to the open-closed field line boundary. For this reason, we estimate the sputtering rates expected in the polar regions due to energetic heavy ions. Other rates, such as those related to radiolysis by plasma and particles that can reach the surface, need to be added to complete the picture of charged particle weathering

    The comitology game: European policymaking with parliamentary involvement

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    This paper discusses institutional reforms that might strengthen the role of the European Parliament in the policymaking process of the European Union. Using simple game theory, the paper analyzes the working properties of the different implementation procedures that are known as ‘comitology’. The Council of the European Union employs these procedures when it delegates some of its policymaking power to the Commission as part of Union legislation. We show how the balance of power is determined by the current comitology procedures, and how this balance would change if the role of the European Parliament were strengthened in the comitology game

    The Energetic Particle Detector (EPD) Investigation and the Energetic Ion Spectrometer (EIS) for the Magnetospheric Multiscale (MMS) Mission

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    Abstract The Energetic Particle Detector (EPD) Investigation is one of 5 fields-and-particles investigations on the Magnetospheric Multiscale (MMS) mission. MMS comprises 4 spacecraft flying in close formation in highly elliptical, near-Earth-equatorial orbits targeting understanding of the fundamental physics of the important physical process called magnetic reconnection using Earth’s magnetosphere as a plasma laboratory. EPD comprises two sensor types, the Energetic Ion Spectrometer (EIS) with one instrument on each of the 4 spacecraft, and the Fly’s Eye Energetic Particle Spectrometer (FEEPS) with 2 instruments on each of the 4 spacecraft. EIS measures energetic ion energy, angle and elemental compositional distributions from a required low energy limit of 20 keV for protons and 45 keV for oxygen ions, up to \u3e0.5 MeV (with capabilities to measure up to \u3e1 MeV). FEEPS measures instantaneous all sky images of energetic electrons from 25 keV to \u3e0.5 MeV, and also measures total ion energy distributions from 45 keV to \u3e0.5 MeV to be used in conjunction with EIS to measure all sky ion distributions. In this report we describe the EPD investigation and the details of the EIS sensor. Specifically we describe EPD-level science objectives, the science and measurement requirements, and the challenges that the EPD team had in meeting these requirements. Here we also describe the design and operation of the EIS instruments, their calibrated performances, and the EIS in-flight and ground operations. Blake et al. (The Flys Eye Energetic Particle Spectrometer (FEEPS) contribution to the Energetic Particle Detector (EPD) investigation of the Magnetospheric Magnetoscale (MMS) Mission, this issue) describe the design and operation of the FEEPS instruments, their calibrated performances, and the FEEPS in-flight and ground operations. The MMS spacecraft will launch in early 2015, and over its 2-year mission will provide comprehensive measurements of magnetic reconnection at Earth’s magnetopause during the 18 months that comprise orbital phase 1, and magnetic reconnection within Earth’s magnetotail during the about 6 months that comprise orbital phase 2

    An empirical approach to modeling ion production rates in Titan’s ionosphere I: Ion production rates on the dayside and globally

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    Titan's ionosphere is created when solar photons, energetic magnetospheric electrons or ions, and cosmic rays ionize the neutral atmosphere. Electron densities generated by current theoretical models are much larger than densities measured by instruments on board the Cassini orbiter. This model density overabundance must result either from overproduction or from insufficient loss of ions. This is the first of two papers that examines ion production rates in Titan's ionosphere, for the dayside and nightside ionosphere, respectively. The first (current) paper focuses on dayside ion production rates which are computed using solar ionization sources (photoionization and electron impact ionization by photoelectrons) between 1000 and 1400 km. In addition to theoretical ion production rates, empirical ion production rates are derived from CH4, CH3+, and CH4+ densities measured by the INMS (Ion Neutral Mass Spectrometer) for many Titan passes. The modeled and empirical production rate profiles from measured densities of N2+ and CH4+ are found to be in good agreement (to within 20%) for solar zenith angles between 15 and 90°. This suggests that the overabundance of electrons in theoretical models of Titan's dayside ionosphere is not due to overproduction but to insufficient ion losses

    Risk of Subsequent Coronary Heart Disease in Patients Hospitalized for Immune-Mediated Diseases: A Nationwide Follow-Up Study from Sweden

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    Background: Certain immune-mediated diseases (IMDs), such as rheumatoid arthritis and systemic lupus erythematosus, have been linked to cardiovascular disorders. We examined whether there is an association between 32 different IMDs and risk of subsequent hospitalization for coronary heart disease (CHD) related to coronary atherosclerosis in a nationwide follow up study in Sweden. Methods and Findings: All individuals in Sweden hospitalized with a main diagnosis of an IMD (n = 336,479) without previous or coexisting CHD, between January 1, 1964 and December 31 2008, were followed for first hospitalization for CHD. The reference population was the total population of Sweden. Standardized incidence ratios (SIRs) for CHD were calculated. Overall risk of CHD during the first year after hospitalization for an IMD was 2.92 (95 % CI 2.84–2.99). Twentyseven of the 32 IMDs studied were associated with an increased risk of CHD during the first year after hospitalization. The overall risk of CHD decreased over time, from 1.75 after 1–5 years (95 % CI 1.73–1.78), to 1.43 after 5–10 years (95 % CI 1.41– 1.46) and 1.28 after 10+ years (95 % CI 1.26–1.30). Females generally had higher SIRs than males. The IMDs for which the SIRs of CDH were highest during the first year after hospitalization included chorea minor 6.98 (95 % CI 1.32–20.65), systemic lupus erythematosus 4.94 (95 % CI 4.15–5.83), rheumatic fever 4.65 (95 % CI 3.53–6.01), Hashimoto’s thyroiditis 4.30 (95 % CI 3.87–4.75), polymyositis/dermatomyositis 3.81 (95 % CI 2.62–5.35), polyarteritis nodosa 3.81 (95 % CI 2.72–5.19), rheumatoi

    Consumer vulnerability and the transformative potential of Internet shopping: An exploratory case study

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    Ten million individuals in the UK who suffer from long-term illness, impairments or disability can be considered as vulnerable consumers (Office for Disability Issues, 2010). Despite this, there are few studies on the use of the Internet for grocery shopping by the disabled and none which offers an understanding of the multiple facets of consumer vulnerability. The purpose of this study is to contextualise the use of the Internet for grocery shopping using an exploratory case to provide fresh insights into the 'actual' vulnerability of "Danni" – a disabled housewife and mother. The consumer focussed methods used here were combined multiple complementary approaches. The findings illustrate that whilst the use of the Internet reduces the impracticalities of shopping in-store, the normalcy afforded to Danni through shopping in-store (including her sense of self) was not met by the technological offerings. The paradoxes associated with using online provision and the strategies adopted to manage these by Danni demonstrate engagement/disengagement and assimilation/isolation. Policy implications and insights for retailers are provided

    Risk of subsequent ischemic and hemorrhagic stroke in patients hospitalized for immune-mediated diseases: a nationwide follow-up study from Sweden

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    Background: Certain immune-mediated diseases (IMDs) have been associated with increased risk for cardiovascular disorders. The aim of the present study was to examine whether there is an association between 32 different IMDs and first hospitalization for ischemic or hemorrhagic stroke. Methods: All individuals in Sweden hospitalized with a main diagnosis of IMD (without previous or coexisting stroke), between January 1, 1987 and December 31, 2008 (n = 216,291), were followed for first hospitalization for ischemic or hemorrhagic stroke. The reference population was the total population of Sweden. Adjusted standardized incidence ratios (SIRs) for ischemic and hemorrhagic stroke were calculated. Results: Totally 20 and 15 of the 32 IMDs studied, respectively, were associated with an increased risk of ischemic and hemorrhagic stroke during the follow-up. The overall risks of ischemic and hemorrhagic stroke during the first year after hospitalization for IMD were 2.02 (95 % CI 1.90-2.14) and 2.65 (95 % CI 2.27-3.08), respectively. The overall risk of ischemic or hemorrhagic stroke decreased over time, to 1.50 (95 % CI 1.46-1.55) and 1.83 (95 % CI 1.69-1.98), respectively, after 1-5 years, and 1.29 (95 % CI 1.23-1.35) and 1.47 (95 % CI 1.31-1.65), respectively, after 10+ years. The risk of hemorrhagic stroke was >= 2 during the first year after hospitalization for seven IMDs: ankylosing spondylitis (SIR = 8.11), immune thrombocytopenic purpura (SIR = 8.60), polymyalgia rheumatica (SIR = 2.06), psoriasis (SIR = 2.88), rheumatoid arthritis (SIR = 3.27), systemic lupus erythematosus (SIR = 8.65), and Wegener ' s granulomatosis (SIR = 5.83). The risk of ischemic stroke was >= 2 during the first year after hospitalization for twelve IMDs: Addison's disease (SIR = 2.71), Crohn's disease (SIR = 2.15), Grave's disease (SIR = 2.15), Hashimoto's thyroiditis (SIR = 2.99), immune thrombocytopenic purpura (SIR = 2.35), multiple sclerosis (SIR = 3.05), polymyositis/dermatomyositis (SIR = 3.46), rheumatic fever (SIR = 3.91), rheumatoid arthritis (SIR = 2.08), Sjgren's syndrome (SIR = 2.57), systemic lupus erythematosus (SIR = 2.21), and ulcerative colitis (SIR = 2.15). Conclusions: Hospitalization for many IMDs is associated with increased risk of ischemic or hemorrhagic stroke. The findings suggest that several IMDs are linked to cerebrovascular disease

    Interstellar Mapping and Acceleration Probe (IMAP): A New NASA Mission

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    The Interstellar Mapping and Acceleration Probe (IMAP) is a revolutionary mission that simultaneously investigates two of the most important overarching issues in Heliophysics today: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. While seemingly disparate, these are intimately coupled because particles accelerated in the inner heliosphere play critical roles in the outer heliospheric interaction. Selected by NASA in 2018, IMAP is planned to launch in 2024. The IMAP spacecraft is a simple sun-pointed spinner in orbit about the Sun-Earth L1 point. IMAP’s ten instruments provide a complete and synergistic set of observations to simultaneously dissect the particle injection and acceleration processes at 1 AU while remotely probing the global heliospheric interaction and its response to particle populations generated by these processes. In situ at 1 AU, IMAP provides detailed observations of solar wind electrons and ions; suprathermal, pickup, and energetic ions; and the interplanetary magnetic field. For the outer heliosphere interaction, IMAP provides advanced global observations of the remote plasma and energetic ions over a broad energy range via energetic neutral atom imaging, and precise observations of interstellar neutral atoms penetrating the heliosphere. Complementary observations of interstellar dust and the ultraviolet glow of interstellar neutrals further deepen the physical understanding from IMAP. IMAP also continuously broadcasts vital real-time space weather observations. Finally, IMAP engages the broader Heliophysics community through a variety of innovative opportunities. This paper summarizes the IMAP mission at the start of Phase A development

    Science Overview of the Europa Clipper Mission

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    The goal of NASA’s Europa Clipper mission is to assess the habitability of Jupiter’s moon Europa. After entering Jupiter orbit in 2030, the flight system will collect science data while flying past Europa 49 times at typical closest approach distances of 25–100 km. The mission’s objectives are to investigate Europa’s interior (ice shell and ocean), composition, and geology; the mission will also search for and characterize any current activity including possible plumes. The science objectives will be accomplished with a payload consisting of remote sensing and in-situ instruments. Remote sensing investigations cover the ultraviolet, visible, near infrared, and thermal infrared wavelength ranges of the electromagnetic spectrum, as well as an ice-penetrating radar. In-situ investigations measure the magnetic field, dust grains, neutral gas, and plasma surrounding Europa. Gravity science will be achieved using the telecommunication system, and a radiation monitoring engineering subsystem will provide complementary science data. The flight system is designed to enable all science instruments to operate and gather data simultaneously. Mission planning and operations are guided by scientific requirements and observation strategies, while appropriate updates to the plan will be made tactically as the instruments and Europa are characterized and discoveries emerge. Following collection and validation, all science data will be archived in NASA’s Planetary Data System. Communication, data sharing, and publication policies promote visibility, collaboration, and mutual interdependence across the full Europa Clipper science team, to best achieve the interdisciplinary science necessary to understand Europa
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