Acceleration of electrons by whistler-mode hiss waves at Saturn

Plasmaspheric hiss waves at the Earth are well known for causing losses of electrons from the radiation belts through wave particle interactions. At Saturn, however, we show that the different plasma density environment leads to acceleration of the electrons rather than loss. The ratio of plasma frequency to electron gyrofrequency frequently falls below one creating conditions for hiss to accelerate electrons. The location of hiss at high latitudes ( > 25°) coincides very well with this region of very low density. The interaction between electrons and hiss only occurs at these higher latitudes, therefore the acceleration is limited to mid to low pitch angles leading to butterfly pitch angle distributions. The hiss is typically an order of magnitude stronger than chorus at Saturn and the resulting acceleration is rapid, approaching steady state in one day at 0.4 MeV at L=7 and the effect is stronger with increasing L-shell

Ultra-Low Power on Skin ECG using RFID Communication

Electrocardiograms provide rhythm, rate and electrical activity of the heart which can be used to diagnose health issues. Current methodologies for wireless based heart monitoring favour the use of Bluetooth Low Energy, which can require bulky batteries for device longevity. This paper investigates the use of a novel ultra-low power communications technique utilising Ultra High Frequency Radio Frequency Identification to stream ECG data in real time to a host computer to enable sub 2mW power consumption

Solar proton events and stratospheric ozone depletion over northern Finland

We examine the variation of stratospheric ozone over northern Finland using ozonesonde observations from 1845 stratospheric balloon flights launched between 1989 and 2015 from near Sodankylä. The annual variation of the ozone partial pressure is examined and seasonal variations are explored and quantified. Direct links between the measured ozone partial pressure and common solar-wind parameters are also examined. A superposed-epoch analysis of the observations based on 191 solar proton events (SPEs) reveals a clear drop in the ozone partial pressure that commences following SPE-arrival at Earth. This analysis shows a reduction in stratospheric ozone in the winter/early-spring months (when the polar vortex is active over northern Finland), in contrast to summer/early-autumn months where no decrease is detected. By subtracting the natural seasonal variations in ozone partial pressure the SPE-driven reduction in ozone between 16 km and 24 km altitude is quantified. Analysis indicates that the ozone partial pressure during winter/early-spring is reduced, with a minimum reached ∼8 days following the SPE arrival. On average, the ozone partial pressure is reduced by ∼10% between 16 and 24 km altitude and takes ∼40 days to return to its previous level. To the best of our knowledge, this is the first comprehensive statistical study, on a regional basis, that provides direct, and long-term in-situ evidence for ozone depletion by SPEs in the northern hemisphere

Cassini UVIS Observations of the Io Plasma Torus. IV. Modeling Temporal and Azimuthal Variability

In this fourth paper in a series, we present a model of the remarkable temporal and azimuthal variability of the Io plasma torus observed during the Cassini encounter with Jupiter. Over a period of three months, the Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a dramatic variation in the average torus composition. Superimposed on this long-term variation, is a 10.07-hour periodicity caused by an azimuthal variation in plasma composition subcorotating relative to System III longitude. Quite surprisingly, the amplitude of the azimuthal variation appears to be modulated at the beat frequency between the System III period and the observed 10.07-hour period. Previously, we have successfully modeled the months-long compositional change by supposing a factor of three increase in the amount of material supplied to Io's extended neutral clouds. Here, we extend our torus chemistry model to include an azimuthal dimension. We postulate the existence of two azimuthal variations in the number of super-thermal electrons in the torus: a primary variation that subcorotates with a period of 10.07 hours and a secondary variation that remains fixed in System III longitude. Using these two hot electron variations, our model can reproduce the observed temporal and azimuthal variations observed by Cassini UVIS.Comment: Revised 24 August 2007 Accepted by Icarus, 50 pages, 2 Tables, 8 figure

The first spectroscopic IR reverberation programme on Mrk 509

Near IR spectroscopic reverberation of Active Galactic Nuclei (AGN) potentially allows the IR broad line region (BLR) to be reverberated alongside the disc and dust continua, while the spectra can also reveal details of dust astro-chemistry. Here we describe results of a short pilot study (17 near-IR spectra over a 183 day period) for Mrk 509. The spectra give a luminosity-weighted dust radius of 〈Rd, lum〉 = 186 ± 4 light-days for blackbody (large grain dust), consistent with previous (photometric) reverberation campaigns, whereas carbon and silicate dust give much larger radii. We develop a method of calibrating spectral data in objects where the narrow lines are extended beyond the slit width. We demonstrate this by showing our resultant photometric band lightcurves are consistent with previous results, with a hot dust lag at >40 days in the K-band, clearly different from the accretion disc response at <20 days in the z-band. We place this limit of 40 days by demonstrating clearly that the modest variability that we do detect in the H and K-band does not reverberate on timescales of less than 40 days. We also extract the Paβ line lightcurve, and find a lag which is consistent with the optical BLR Hβ line of ∼70 − 90 days. This is important as direct imaging of the near-IR BLR is now possible in a few objects, so we need to understand its relation to the better studied optical BLR

Active Galaxies in the UV

In this article we present different aspects of AGN studies demonstrating the importance of the UV spectral range. Most important diagnostic lines for studying the general physical conditions as well as the metalicities in the central broad line region in AGN are emitted in the UV. The UV/FUV continuum in AGN excites not only the emission lines in the immediate surrounding but it is responsible for the ionization of the intergalactic medium in the early stages of the universe. Variability studies of the emission line profiles of AGN in the UV give us information on the structure and kinematics of the immediate surrounding of the central supermassive black hole as well as on its mass itself.Comment: 29 pages, 13 figures, Ap&SS in pres

Revisiting software protection

We provide a selective survey on software protection, including approaches to software tamper resistance, obfuscation, software diversity, and white-box cryptography. We review the early literature in the area plus recent activities related to trusted platforms, and discuss challenges and future directions

Anthropogenic Space Weather

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

Relations between lipoprotein(a) concentrations, LPA genetic variants, and the risk of mortality in patients with established coronary heart disease: a molecular and genetic association study

Background: Lipoprotein(a) concentrations in plasma are associated with cardiovascular risk in the general population. Whether lipoprotein(a) concentrations or LPA genetic variants predict long-term mortality in patients with established coronary heart disease remains less clear. Methods: We obtained data from 3313 patients with established coronary heart disease in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. We tested associations of tertiles of lipoprotein(a) concentration in plasma and two LPA single-nucleotide polymorphisms ([SNPs] rs10455872 and rs3798220) with all-cause mortality and cardiovascular mortality by Cox regression analysis and with severity of disease by generalised linear modelling, with and without adjustment for age, sex, diabetes diagnosis, systolic blood pressure, BMI, smoking status, estimated glomerular filtration rate, LDL-cholesterol concentration, and use of lipid-lowering therapy. Results for plasma lipoprotein(a) concentrations were validated in five independent studies involving 10 195 patients with established coronary heart disease. Results for genetic associations were replicated through large-scale collaborative analysis in the GENIUS-CHD consortium, comprising 106 353 patients with established coronary heart disease and 19 332 deaths in 22 studies or cohorts. Findings: The median follow-up was 9·9 years. Increased severity of coronary heart disease was associated with lipoprotein(a) concentrations in plasma in the highest tertile (adjusted hazard radio [HR] 1·44, 95% CI 1·14–1·83) and the presence of either LPA SNP (1·88, 1·40–2·53). No associations were found in LURIC with all-cause mortality (highest tertile of lipoprotein(a) concentration in plasma 0·95, 0·81–1·11 and either LPA SNP 1·10, 0·92–1·31) or cardiovascular mortality (0·99, 0·81–1·2 and 1·13, 0·90–1·40, respectively) or in the validation studies. Interpretation: In patients with prevalent coronary heart disease, lipoprotein(a) concentrations and genetic variants showed no associations with mortality. We conclude that these variables are not useful risk factors to measure to predict progression to death after coronary heart disease is established. Funding: Seventh Framework Programme for Research and Technical Development (AtheroRemo and RiskyCAD), INTERREG IV Oberrhein Programme, Deutsche Nierenstiftung, Else-Kroener Fresenius Foundation, Deutsche Stiftung für Herzforschung, Deutsche Forschungsgemeinschaft, Saarland University, German Federal Ministry of Education and Research, Willy Robert Pitzer Foundation, and Waldburg-Zeil Clinics Isny