Solar Energetic Particles and Solar Events - Lessons Learned from Multi-Spacecraft Observations

Never before has the heliosphere and the Sun been so carefully monitored by so many spacecraft; in particular, the STEREO spacecraft have allowed simultaneous observations to be made routinely from multiple solar longitudes. The instrumentation on these spacecraft are continually observing solar activity and measuring the characteristics of solar energetic particle (SEP) events, providing a wealth of information on the acceleration and transport of SEPs. In February, 2011 the STEREO spacecraft reached a separation of 180° and since then the entire solar surface has been visible. This unprecedented view has allowed observations of active regions and solar activity to continue after a region has rotated over the limb (as view from Earth) and more importantly, of regions emerging on the solar hemisphere not visible to Earth. The multiple viewpoints afforded by spectrometers and coronagraphs on the STEREO and near-Earth spacecraft has yielded more accurate information regarding the speed, direction, and evolution of coronal mass ejections (CMEs) which drive the interplanetary shocks that generate large SEP events. As is often the case when new capabilities are achieved or new regimes are explored, even while some questions are answered, more emerge. Among the surprises from multi-spacecraft SEP observations is the exceptionally fast longitudinal transport of particles. This paper reviews these multi-spacecraft capabilities, highlights some of the recent observations and surprises, and discusses the impact on the current understanding of energetic particle acceleration and transport

Feminists really do count : the complexity of feminist methodologies

We are delighted to be presenting this special issue on the topic of feminism and quantitative methods. We believe that such an issue is exceptionally timely. This is not simply because of ongoing debates around quantification within the field of feminism and women‟s studies. It is also because of debates within the wider research community about the development of appropriate methodologies that take account of new technological and philosophical concerns and are fit-for-purpose for researching contemporary social, philosophical, cultural and global issues. Two areas serve as exemplars in this respect and both speak to these combined wider social science and specifically feminist methodological concerns. The first is the increasing concern amongst social scientists with how the complexity of social life can be captured and analysed. Within feminism, this can be seen in debates about intersectionality that recognise the concerns arising from multiple social positions/divisions and associated power issues. As Denis (2008: 688) comments in respect of intersectional analysis „The challenge of integrating multiple, concurrent, yet often contradictory social locations into analyses of power relations has been issued. Theorising to accomplish this end is evolving, and we are struggling to develop effective methodological tools in order to marry theorising with necessary complex analyses of empirical data.‟ Secondly, new techniques and new data sources are now coming on line. This includes work in the UK of the ESRC National Data Strategy which has been setting out the priorities for the development of research data resources both within and across the boundaries of the social sciences. This will facilitate historical, longitudinal, interdisciplinary and mixed methodological research. And it may be the case that these developments facilitate the achievement of a longstanding feminist aim not simply for interdisciplinarity but for transdisciplinarity in epistemological and methodological terms

A comparison of short-term and long-term air pollution exposure associations with mortality in two cohorts in Scotland

Air pollution–mortality risk estimates are generally larger at longer-term, compared with short-term, exposure time scales. We compared associations between short-term exposure to black smoke (BS) and mortality with long-term exposure–mortality associations in cohort participants and with short-term exposure–mortality associations in the general population from which the cohorts were selected. We assessed short-to-medium–term exposure–mortality associations in the Renfrew–Paisley and Collaborative cohorts (using nested case–control data sets), and compared them with long-term exposure–mortality associations (using a multilevel spatiotemporal exposure model and survival analyses) and short-to-medium–term exposure–mortality associations in the general population (using time-series analyses). For the Renfrew–Paisley cohort (15,331 participants), BS exposure–mortality associations were observed in nested case–control analyses that accounted for spatial variations in pollution exposure and individual-level risk factors. These cohort-based associations were consistently greater than associations estimated in time-series analyses using a single monitoring site to represent general population exposure {e.g., 1.8% [95% confidence interval (CI): 0.1, 3.4%] vs. 0.2% (95% CI: 0.0, 0.4%) increases in mortality associated with 10-μg/m3 increases in 3-day lag BS, respectively}. Exposure–mortality associations were of larger magnitude for longer exposure periods [e.g., 3.4% (95% CI: –0.7, 7.7%) and 0.9% (95% CI: 0.3, 1.5%) increases in all-cause mortality associated with 10-μg/m3 increases in 31-day BS in case–control and time-series analyses, respectively; and 10% (95% CI: 4, 17%) increase in all-cause mortality associated with a 10-μg/m3 increase in geometic mean BS for 1970–1979, in survival analysis]. After adjusting for individual-level exposure and potential confounders, short-term exposure–mortality associations in cohort participants were of greater magnitude than in comparable general population time-series study analyses. However, short-term exposure–mortality associations were substantially lower than equivalent long-term associations, which is consistent with the possibility of larger, more persistent cumulative effects from long-term exposures

Shoulder arthroscopy positioning: lateral decubitus versus beach chair.

Since the introduction of the beach chair position for shoulder arthroscopy, orthopaedic surgeons have debated whether the beach chair or lateral decubitus is superior. Most surgeons use the same patient position to perform all of their arthroscopic shoulder procedures, regardless of the pathology. Each position has its advantages and disadvantages. The evidence regarding the efficiency, efficacy, and risks of the lateral decubitus and the beach chair positions for shoulder arthroscopy does not show one position to be superior. This review presents a comparison of these positions with regard to setup, surgical visualization, access, and patient risk

Solar Energetic Particles and Solar Events - Lessons Learned from Multi-Spacecraft Observations

Never before has the heliosphere and the Sun been so carefully monitored by so many spacecraft; in particular, the STEREO spacecraft have allowed simultaneous observations to be made routinely from multiple solar longitudes. The instrumentation on these spacecraft are continually observing solar activity and measuring the characteristics of solar energetic particle (SEP) events, providing a wealth of information on the acceleration and transport of SEPs. In February, 2011 the STEREO spacecraft reached a separation of 180° and since then the entire solar surface has been visible. This unprecedented view has allowed observations of active regions and solar activity to continue after a region has rotated over the limb (as view from Earth) and more importantly, of regions emerging on the solar hemisphere not visible to Earth. The multiple viewpoints afforded by spectrometers and coronagraphs on the STEREO and near-Earth spacecraft has yielded more accurate information regarding the speed, direction, and evolution of coronal mass ejections (CMEs) which drive the interplanetary shocks that generate large SEP events. As is often the case when new capabilities are achieved or new regimes are explored, even while some questions are answered, more emerge. Among the surprises from multi-spacecraft SEP observations is the exceptionally fast longitudinal transport of particles. This paper reviews these multi-spacecraft capabilities, highlights some of the recent observations and surprises, and discusses the impact on the current understanding of energetic particle acceleration and transport

The solar wind ionic charge states during the Ulysses pole-to-pole pass

We analyze and compare the ionic charge composition data for different types of the solar wind which the Solar Wind Ion Composition Spectrometer on Ulysses observed during the pole-to-pole pass of its primary mission. The implications on the electron temperature, electron density and ion outflow velocity from the corresponding solar wind source regions are also discussed. We find that the electron temperature in the source region of the slow solar wind is higher than that in the coronal hole. We also find a possible north-south asymmetry in the electron temperature that may be correlated to the north-south asymmetry in the solar wind speed found in the SWOOPS/Ulysses data. Based on our data without clear constraints from other coronal observations, it is found that the electron density may be higher, or the heavy ion outflow velocities may be lower toward lower heliographic latitude. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87726/2/491_1.pd

Nanoscale Magnetic Imaging using Circularly Polarized High-Harmonic Radiation

This work demonstrates nanoscale magnetic imaging using bright circularly polarized high-harmonic radiation. We utilize the magneto-optical contrast of worm-like magnetic domains in a Co/Pd multilayer structure, obtaining quantitative amplitude and phase maps by lensless imaging. A diffraction-limited spatial resolution of 49 nm is achieved with iterative phase reconstruction enhanced by a holographic mask. Harnessing the unique coherence of high harmonics, this approach will facilitate quantitative, element-specific and spatially-resolved studies of ultrafast magnetization dynamics, advancing both fundamental and applied aspects of nanoscale magnetism.Comment: Ofer Kfir and Sergey Zayko contributed equally to this work. Presented in CLEO 2017 (Oral) doi.org/10.1364/CLEO_QELS.2017.FW1H.

STEREO Observations of Solar Energetic Particles

We report on observations of Solar Energetic Particle (SEP) events as observed by instruments on the STEREO Ahead and Behind spacecraft and on the ACE spacecraft. We will show observations of an electron event observed by the STEREO Ahead spacecraft on June 12, 2010 located at W74 essentially simultaneously with electrons seen at STEREO Behind at E70. Some similar events observed by Helios were ascribed to fast electron propagation in longitude close to the sun. We will look for independent verification of this possibility. We will also show observations of what appears to be a single proton event with very similar time-history profiles at both of the STEREO spacecraft at a similar wide separation. This is unexpected. We will attempt to understand all of these events in terms of corresponding CME and radio burst observations