The proportion of women living with a diagnosis of breast cancer in developed countries is increasing. Because breast cancer-specific deaths decrease with time since diagnosis, it is important to ...assess the burden of other causes of death in women diagnosed with breast cancer.
Different causes of death within 10 years from diagnosis were assessed in 12,850 women younger than 75 years of age with stage 1 to 3 breast cancer diagnosed in Stockholm and Gotland regions 1990 to 2006. Flexible parametric survival models were used to estimate hazard ratios over time since diagnosis by tumor characteristics and age at diagnosis.
The proportion of deaths attributed to breast cancer ranged from 95.0% among women younger than age 45 years at diagnosis to 44.5% among women age 65 to 74 years. The proportions of circulatory system-specific deaths and deaths resulting from other causes increased with older age at diagnosis. Patients with one to three positive lymph nodes were more likely to die as a result of breast cancer during the first 10 years of follow-up compared with women without positive lymph nodes. Women with estrogen receptor (ER) -positive tumors had the same risk of dying as a result of breast cancer 5 years after diagnosis compared with women with ER-negative tumors.
Lymph node negativity is an important long-term predictor of more favorable prognosis. The nature of the relationship between ER status and risk of dying as a result of breast cancer after 5 years of follow-up requires further investigation. Circulatory system diseases are an important cause of death, especially in women diagnosed with breast cancer at an older age.
A major point of interest in cometary plasma physics has been the diamagnetic cavity, an unmagnetized region in the innermost part of the coma. Here we combine Langmuir and Mutual Impedance Probe ...measurements to investigate ion velocities and electron temperatures in the diamagnetic cavity of comet 67P, probed by the Rosetta spacecraft. We find ion velocities generally in the range 2–4 km/s, significantly above the expected neutral velocity
≲1 km/s, showing that the ions are (partially) decoupled from the neutrals, indicating that ion‐neutral drag was not responsible for balancing the outside magnetic pressure. Observations of clear wake effects on one of the Langmuir probes showed that the ion flow was close to radial and supersonic, at least with respect to the perpendicular temperature, inside the cavity and possibly in the surrounding region as well. We observed spacecraft potentials
≲−5 V throughout the cavity, showing that a population of warm (∼5 eV) electrons was present throughout the parts of the cavity reached by Rosetta. Also, a population of cold (
≲0.1eV) electrons was consistently observed throughout the cavity, but less consistently in the surrounding region, suggesting that while Rosetta never entered a region of collisionally coupled electrons, such a region was possibly not far away during the cavity crossings.
Key Points
The ion velocity exceeded the neutral velocity, showing that the ions were not strongly collisionally coupled to the neutral gas
A population of warm electrons was present throughout the parts of the cavity reached by Rosetta, driving the spacecraft potential negative
A population of cold electrons was consistently observed inside the cavity and intermittently also in the surrounding region
Although several studies have investigated the association of the Mediterranean diet with overall mortality or risk of specific cancers, data on overall cancer risk are sparse.
We examined the ...association between adherence to Mediterranean dietary pattern and overall cancer risk using data from the European Prospective Investigation Into Cancer and nutrition, a multi-centre prospective cohort study including 142,605 men and 335,873. Adherence to Mediterranean diet was examined using a score (range: 0-9) considering the combined intake of fruits and nuts, vegetables, legumes, cereals, lipids, fish, dairy products, meat products, and alcohol. Association with cancer incidence was assessed through Cox regression modelling, controlling for potential confounders.
In all, 9669 incident cancers in men and 21,062 in women were identified. A lower overall cancer risk was found among individuals with greater adherence to Mediterranean diet (hazard ratio=0.96, 95% CI 0.95-0.98) for a two-point increment of the Mediterranean diet score. The apparent inverse association was stronger for smoking-related cancers than for cancers not known to be related to tobacco (P (heterogeneity)=0.008). In all, 4.7% of cancers among men and 2.4% in women would be avoided in this population if study subjects had a greater adherence to Mediterranean dietary pattern.
Greater adherence to a Mediterranean dietary pattern could reduce overall cancer risk.
Context. Strong electron cooling on the neutral gas in cometary comae has been predicted for a long time, but actual measurements of low electron temperature are scarce. Aims. Our aim is to ...demonstrate the existence of cold electrons in the inner coma of comet 67P/Churyumov-Gerasimenko and show filamentation of this plasma. Methods. In situ measurements of plasma density, electron temperature and spacecraft potential were carried out by the Rosetta Langmuir probe instrument, LAP. We also performed analytical modelling of the expanding two-temperature electron gas. Results. LAP data acquired within a few hundred km from the nucleus are dominated by a warm component with electron temperature typically 5–10 eV at all heliocentric distances covered (1.25 to 3.83 AU). A cold component, with temperature no higher than about 0.1 eV, appears in the data as short (few to few tens of seconds) pulses of high probe current, indicating local enhancement of plasma density as well as a decrease in electron temperature. These pulses first appeared around 3 AU and were seen for longer periods close to perihelion. The general pattern of pulse appearance follows that of neutral gas and plasma density. We have not identified any periods with only cold electrons present. The electron flux to Rosetta was always dominated by higher energies, driving the spacecraft potential to order − 10 V. Conclusions. The warm (5–10 eV) electron population observed throughout the mission is interpreted as electrons retaining the energy they obtained when released in the ionisation process. The sometimes observed cold populations with electron temperatures below 0.1 eV verify collisional cooling in the coma. The cold electrons were only observed together with the warm population. The general appearance of the cold population appears to be consistent with a Haser-like model, implicitly supporting also the coupling of ions to the neutral gas. The expanding cold plasma is unstable, forming filaments that we observe as pulses.
Abstract
Comet Interceptor will be the first mission to make a flyby of a long-period or interstellar comet. After launch, the spacecraft will wait at the Sun–Earth Lagrange point L2 for a ...yet-to-be-discovered comet to appear. The mission comprises three spacecraft: One main spacecraft, A, developed by ESA, and two subprobes, B1 and B2, developed by JAXA and ESA, respectively. All spacecraft will carry plasma instruments for a three-dimensional sampling of the cometary plasma environment. The plasma measurements will likely be affected by the spacecraft potential and by particles emitted from the spacecraft surface. In this work, we use the Spacecraft Plasma Interaction Software and the ElectroMagnetic Spacecraft Environment Simulator to make particle-in-cell simulations of the spacecraft–plasma interactions of probe B1 in different environments during the cometary flyby. This is done for two production rates of the target comet and two relative flyby velocities of the probe. At low flyby velocities, the spacecraft potential varies from 9 V in the solar wind to −5 V in the inner coma for a comet similar to comet 67P/Churyumov–Gerasimenko. For a comet similar to 1P/Halley, the potential is slightly less negative in the inner coma due to the more effective collisional cooling of the electrons in the environment. At high flyby velocities, secondary electron emissions from neutral gas impacts dominate the currents, charging the probe to positive potentials in most of the studied environments.
Context. The Rosetta spacecraft provided us with a unique opportunity to study comet 67P/Churyumov–Gerasimenko (67P) from a close perspective and over a 2-yr time period. Comet 67P is a weakly active ...comet. It was therefore unexpected to find an active and dynamic ionosphere where the cometary ions were largely dominant over the solar wind ions, even at large heliocentric distances. Aims. Our goal is to understand the different drivers of the cometary ionosphere and assess their variability over time and over the different conditions encountered by the comet during the Rosetta mission. Methods. We used a multi-instrument data-based ionospheric model to compute the total ion number density at the position of Rosetta. In-situ measurements from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the Rosetta Plasma Consortium (RPC)–Ion and Electron Sensor (IES), together with the RPC–LAngmuir Probe instrument (LAP) were used to compute the local ion total number density. The results are compared to the electron densities measured by RPC–Mutual Impedance Probe (MIP) and RPC–LAP. Results. We were able to disentangle the physical processes responsible for the formation of the cometary ions throughout the 2-yr escort phase and we evaluated their respective magnitudes. The main processes are photo-ionization and electron-impact ionization. The latter is a significant source of ionization at large heliocentric distance (>2 au) and was predominant during the last 4 months of the mission. The ionosphere was occasionally subject to singular solar events, temporarily increasing the ambient energetic electron population. Solar photons were the main ionizer near perihelion at 1.3 au from the Sun, during summer 2015.
Aims.
We aim to determine whether dissociative excitation of cometary neutrals by electron impact is the major source of far-ultraviolet (FUV) emissions at comet 67P/Churyumov-Gerasimenko in the ...southern hemisphere at large heliocentric distances, both during quiet conditions and impacts of corotating interaction regions observed in the summer of 2016.
Methods.
We combined multiple datasets from the Rosetta mission through a multi-instrument analysis to complete the first forward modelling of FUV emissions in the southern hemisphere of comet 67P and compared modelled brightnesses to observations with the Alice FUV imaging spectrograph. We modelled the brightness of OI1356, OI1304, Lyman-
β
, CI1657, and CII1335 emissions, which are associated with the dissociation products of the four major neutral species in the coma: CO
2
, H
2
O, CO, and O
2
. The suprathermal electron population was probed by the Ion and Electron Sensor of the Rosetta Plasma Consortium and the neutral column density was constrained by several instruments: the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), the Microwave Instrument for the Rosetta Orbiter and the Visual InfraRed Thermal Imaging Spectrometer.
Results.
The modelled and observed brightnesses of the FUV emission lines agree closely when viewing nadir and dissociative excitation by electron impact is shown to be the dominant source of emissions away from perihelion. The CII1335 emissions are shown to be consistent with the volume mixing ratio of CO derived from ROSINA. When viewing the limb during the impacts of corotating interaction regions, the model reproduces brightnesses of OI1356 and CI1657 well, but resonance scattering in the extended coma may contribute significantly to the observed Lyman-
β
and OI1304 emissions. The correlation between variations in the suprathermal electron flux and the observed FUV line brightnesses when viewing the comet’s limb suggests electrons are accelerated on large scales and that they originate in the solar wind. This means that the FUV emissions are auroral in nature.
A comet ionospheric model assuming the plasma moves radially outward with the same bulk speed as the neutral gas and not being subject to severe reduction through dissociative recombination has ...previously been tested in a series of case studies associated with the Rosetta mission at comet 67P/Churyumov-Gerasimenko. It has been found that at low activity and within several tens of kilometers from the nucleus such models (which originally were developed for such conditions) generally work well in reproducing observed electron number densities, in particular when plasma production through both photoionization and electron-impact ionization is taken into account. Near perihelion, case studies have, on the contrary, shown that applying similar assumptions overestimates the observed electron number densities at the location of Rosetta. Here we compare Rosetta Orbiter Spectrometer for Ion and Neutral Analysis/Comet Pressure sensor-driven model results with Rosetta Plasma Consortium/Mutual Impedance Probe-derived electron number densities for an extended time period (2015 November through 2016 March) during the postperihelion phase with southern summer/spring. We observe a gradual transition from a state when the model grossly overestimates (by more than a factor of 10) the observations to being in reasonable agreement during 2016 March.
Abstract
We present and compare measurements of the spacecraft potential (Vs/c) of the Rosetta spacecraft throughout its stay in the inner coma of comet 67P/Churyumov–Gerasimenko, by the Rosetta ...Plasma Consortium-LAngmuir Probe (RPC-LAP) and Ion Composition Analyzer (RPC-ICA) instruments. Vs/c has mainly been negative, driven by the high temperature (∼5–10 eV) of the coma photoelectrons. The magnitude of the negative Vs/c traces heliocentric, cometocentric, seasonal and diurnal variations in cometary outgassing, consistent with production at or inside the cometocentric distance of the spacecraft being the dominant source of the observed plasma. LAP only picks up a portion of the full Vs/c since the two probes, mounted on booms of 2.2 and 1.6 m length, respectively, are generally inside the potential field of the spacecraft. Comparing with the minimum energy of positive ions collected by ICA, we find numerous cases with strong correlation between the two instruments, from which the fraction of Vs/c picked up by LAP is found to vary between about 0.7 and 1. We also find an ICA energy offset of 13.7 eV (95 per cent CI: 12.5, 15.0). Many cases of poor correlation between the instruments are also observed, predominantly when local ion production is weak and accelerated ions dominate the flux, or during quiet periods with low dynamic range in Vs/c and consequently low signal-to-noise ratios.
Context.
The electrostatic potential of a spacecraft,
V
S
, is important for the capabilities of in situ plasma measurements. Rosetta has been found to be negatively charged during most of the comet ...mission and even more so in denser plasmas.
Aims.
Our goal is to investigate how the negative
V
S
correlates with electron density and temperature and to understand the physics of the observed correlation.
Methods.
We applied full mission comparative statistics of
V
S
, electron temperature, and electron density to establish
V
S
dependence on cold and warm plasma density and electron temperature. We also used Spacecraft-Plasma Interaction System (SPIS) simulations and an analytical vacuum model to investigate if positively biased elements covering a fraction of the solar array surface can explain the observed correlations.
Results.
Here, the
V
S
was found to depend more on electron density, particularly with regard to the cold part of the electrons, and less on electron temperature than was expected for the high flux of thermal (cometary) ionospheric electrons. This behaviour was reproduced by an analytical model which is consistent with numerical simulations.
Conclusions.
Rosetta is negatively driven mainly by positively biased elements on the borders of the front side of the solar panels as these can efficiently collect cold plasma electrons. Biased elements distributed elsewhere on the front side of the panels are less efficient at collecting electrons apart from locally produced electrons (photoelectrons). To avoid significant charging, future spacecraft may minimise the area of exposed bias conductors or use a positive ground power system.
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