Dissipation-Scale Turbulence in the Solar Wind

We present a cascade model for turbulence in weakly collisional plasmas that follows the nonlinear cascade of energy from the large scales of driving in the MHD regime to the small scales of the kinetic Alfven wave regime where the turbulence is dissipated by kinetic processes. Steady-state solutions of the model for the slow solar wind yield three conclusions: (1) beyond the observed break in the magnetic energy spectrum, one expects an exponential cut-off; (2) the widely held interpretation that this dissipation range obeys power-law behavior is an artifact of instrumental sensitivity limitations; and, (3) over the range of parameters relevant to the solar wind, the observed variation of dissipation range spectral indices from -2 to -4 is naturally explained by the varying effectiveness of Landau damping, from an undamped prediction of -7/3 to a strongly damped index around -4.Comment: 6 pages, 2 figures, accepted for publication in AIP Conference Proceedings on "Turbulence and Nonlinear Processes in Astrophysical Plasmas

Re-thinking the Legacy 2012: The Olympics as commodity and gift

This paper opens discussion about the nature of Olympic ‘legacy’ and articulates a contradiction in the way ‘legacy’ is conceived - between ’gift’ and ’commodity’ (Mauss 1954).The The paper argues that establishing working definitions and parameters for ‘legacy’ is a difficult task. Defining ‘legacy’ is problematic especially if conceived as an entirely predictable or measurable set of objectives. Indeed, the definition of ‘legacy’ is partly constitutive of the legacy itself, a component of achievements that the city might make. Such a ‘legacy definition’ will become a functional term in the complex planning and evolving conceptions underpinning urban change for some time—if successfully negotiated and if governable. As such, ‘legacy’, and the activities and values entailed to it, can come to provide a catalytic ‘vocabulary of motives’ and a legitimating discourse enabling politicians, communities and their individual representatives to justify investments, evolving strategies and activities connected to and connecting developmental gains in a more or less healthy fashion. It is because of this that legacy and its various meanings come to matter

Sun-Like Magnetic Cycles in the Rapidly-Rotating Young Solar Analog HD 30495

A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial ($\sim$2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, an $\sim$1 Gyr-old G1.5V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at $\sim$1.7 years and a long cycle of $\sim$12 years. We measure three individual long-period cycles and find durations ranging from 9.6-15.5 years. We find the short-term variability to be intermittent, but present throughout the majority of the time series, though its occurrence and amplitude are uncorrelated with the longer cycle. These essentially solar-like variations occur in a Sun-like star with more rapid rotation, though surface differential rotation measurements leave open the possibility of a solar equivalence.Comment: 12 pages, 6 figures. Submitted to Ap

Apollo Saturn 511 effluent measurements from the Apollo 16 launch operations: An experiment

An experiment was performed in conjunction with the Apollo 16 launch to define operational and instrumentational problems associated with launch-vehicle exhaust effluent monitoring. Ground and airborne sampling were performed for CO, CO2, hydrocarbons, and particulates. Sampling systems included filter pads and photometers for particulates and whole-air grab samples for gases. Launch debris was identified in the particulate samples at ground level(taken immediately after launch) and in the airborne measurements (taken 40 to 50 minutes after launch approximately 40 km downwind of the pad). Operational problems were identified and included the need for higher instrumentation mobility and the need for real-time sampling instrumentation as opposed to collection-type samples such as the whole-air grab sample

Shear wave structure of a transect of the Los Angeles basin from multimode surface waves and H/V spectral ratio analysis

We use broad-band stations of the ‘Los Angeles Syncline Seismic Interferometry Experiment’ (LASSIE) to perform a joint inversion of the Horizontal to Vertical spectral ratios (H/V) and multimode dispersion curves (phase and group velocity) for both Rayleigh and Love waves at each station of a dense line of sensors. The H/V of the autocorrelated signal at a seismic station is proportional to the ratio of the imaginary parts of the Green’s function. The presence of low-frequency peaks (∼0.2 Hz) in H/V allows us to constrain the structure of the basin with high confidence to a depth of 6 km. The velocity models we obtain are broadly consistent with the SCEC CVM-H community model and agree well with known geological features. Because our approach differs substantially from previous modelling of crustal velocities in southern California, this research validates both the utility of the diffuse field H/V measurements for deep structural characterization and the predictive value of the CVM-H community velocity model in the Los Angeles region. We also analyse a lower frequency peak (∼0.03 Hz) in H/V and suggest it could be the signature of the Moho. Finally, we show that the independent comparison of the H and V components with their corresponding theoretical counterparts gives information about the degree of diffusivity of the ambient seismic field

Measuring the Long-Term Regional Benefits of Salinity Reduction

Approaches for evaluating salinity management benefits are generalized and extended to incorporate consideration of desalination and long-term changes in salinity concentration and water use patterns. Previous research indicates urban users incur the vast majority of salinity-related damages in affected regions, suggesting municipalities may benefit by considering mitigating actions independent of agriculture. However, previous studies have included no consideration of desalination. Earlier studies have also considered stepped increases in salinity, assuming a single future concentration when estimating the long-term benefits of salinity reduction, an approach inconsistent with the incremental nature of these increases. Long-term changes in water use patterns (urban vs. agricultural), when considered at all, have often been treated in the same stepwise fashion. For this analysis, a suitable region is selected and the benefits of a hypothetical salinity management program are estimated using the approach described. These results are then compared with those obtained through the use of several previous methods. Findings suggest that consideration of desalination and incremental variations in salinity and water use patterns can substantially lower the estimated benefits of regional salinity management programs.benefits, regional water resource modeling, salinity, water quality management, Resource /Energy Economics and Policy,

On the engineering of crucial software

The various aspects of the conventional software development cycle are examined. This cycle was the basis of the augmented approach contained in the original grant proposal. This cycle was found inadequate for crucial software development, and the justification for this opinion is presented. Several possible enhancements to the conventional software cycle are discussed. Software fault tolerance, a possible enhancement of major importance, is discussed separately. Formal verification using mathematical proof is considered. Automatic programming is a radical alternative to the conventional cycle and is discussed. Recommendations for a comprehensive approach are presented, and various experiments which could be conducted in AIRLAB are described

Attribution of intentional causation influences the perception of observed movements: behavioral evidence and neural correlates

Recent research on human agency suggests that intentional causation is associated with a subjective compression in the temporal interval between actions and their effects. That is, intentional movements and their causal effects are perceived as closer together in time than equivalent unintentional movements and their causal effects. This so-called intentional binding effect is consistently found for one's own self-generated actions. It has also been suggested that intentional binding occurs when observing intentional movements of others. However, this evidence is undermined by limitations of the paradigm used. In the current study we aimed to overcome these limitations using a more rigorous design in combination with functional Magnetic Resonance Imaging (fMRI) to explore the neural underpinnings of intentional binding of observed movements. In particular, we aimed to identify brain areas sensitive to the interaction between intentionality and causality attributed to the observed action. Our behavioral results confirmed the occurrence of intentional binding for observed movements using this more rigorous paradigm. Our fMRI results highlighted a collection of brain regions whose activity was sensitive to the interaction between intentionality and causation. Intriguingly, these brain regions have previously been implicated in the sense of agency over one's own movements. We discuss the implications of these results for intentional binding specifically, and the sense of agency more generally