Tribes, state, and technology adoption in arid land management, Syria:

Arid shrub-lands in Syria and elsewhere in West Asia and North Africa are widely thought degraded. Characteristic of these areas is a preponderance of unpalatable shrubs or a lack of overall ground cover with a rise in the associated risks of soil erosion. Migrating pastoralists have been the scapegoats for this condition of the range. State steppe interventions of the last forty years have reflected this with programs to supplant customary systems with structures and institutions promoting western grazing systems and technologies. Principal amongst the latter has been shrub technology, particularly Atriplex species, for use in land rehabilitation and as a fodder reserve. This paper deconstructs state steppe policy in Syria by examining the overlap and interface of government and customary legal systems as a factor in the history of shrub technology transfer in the Syrian steppe. It is argued that the link made between signs of degradation and perceived moribund customary systems is not at all causal. Indeed, customary systems are found to be adaptive and resilient, and a strong influence on steppe management and the fate of technology transfer initiatives. Furthermore, developments in rangeland ecology raise questions about claims for grazing-induced degradation and call for a reinterpretation of recent shifts in vegetation on the Syrian steppe. Given the ineffectiveness of past state interventions, and in view of renewed understanding of customary systems and rangeland ecology, decentralization and some devolution of formal management responsibility is likely to be a viable and an attractive option for policymakers.

Variations of Field Line Eigenfrequencies With Ring Current Intensity

We present results from the closed magnetosphere (5.9≤L < 9.5 over all magnetic local times) to demonstrate and assess the variations in field line eigenfrequency with geomagnetic activity. Using the time-of-flight technique with realistic magnetic field and mass density models, the spatial distributions of field line eigenfrequencies are determined for a range of different geomagnetic activity levels, as defined by the Dst index. The results indicate that during geomagnetically active conditions, the eigenfrequency of a given field line is generally decreased compared to quiet times, in addition to variations in local asymmetries. By comparing the dependence to changes in the magnetic field and mass density distribution, it is established that the inflation and weakening of the geomagnetic field outweighs decreased plasma mass density and is the sole contributor to decreased eigenfrequencies with increased geomagnetic activity. We highlight the importance of considering the magnetic field, mass density, and average ion mass contributions when using observed eigenfrequencies to probe magnetospheric conditions. Furthermore, the estimates significantly improve upon existing time-of-flight results, through a consideration of mass density changes with geomagnetic activity. We also provide estimates of eigenfrequencies for a comparatively extended spatial region than available from prior direct observations of field line resonances. The results have clear implications for furthering our understanding of how wave energy propagates throughout the magnetosphere during geomagnetic storms

Statistics of Solar Wind Electron Breakpoint Energies Using Machine Learning Techniques

Solar wind electron velocity distributions at 1 au consist of a thermal "core" population and two suprathermal populations: "halo" and "strahl". The core and halo are quasi-isotropic, whereas the strahl typically travels radially outwards along the parallel and/or anti-parallel direction with respect to the interplanetary magnetic field. With Cluster-PEACE data, we analyse energy and pitch angle distributions and use machine learning techniques to provide robust classifications of these solar wind populations. Initially, we use unsupervised algorithms to classify halo and strahl differential energy flux distributions to allow us to calculate relative number densities, which are of the same order as previous results. Subsequently, we apply unsupervised algorithms to phase space density distributions over ten years to study the variation of halo and strahl breakpoint energies with solar wind parameters. In our statistical study, we find both halo and strahl suprathermal breakpoint energies display a significant increase with core temperature, with the halo exhibiting a more positive correlation than the strahl. We conclude low energy strahl electrons are scattering into the core at perpendicular pitch angles. This increases the number of Coulomb collisions and extends the perpendicular core population to higher energies, resulting in a larger difference between halo and strahl breakpoint energies at higher core temperatures. Statistically, the locations of both suprathermal breakpoint energies decrease with increasing solar wind speed. In the case of halo breakpoint energy, we observe two distinct profiles above and below 500 km/s. We relate this to the difference in origin of fast and slow solar wind.Comment: Published in Astronomy & Astrophysics, 11 pages, 10 figure

Energy Budget of High-speed Plasma Flows in the Terrestrial Magnetotail

Significant advances have been presented for the theoretical model and quantitative investigation of the energy input from the solar wind and its subsequent release into the ring current, the Joule heating, and particle precipitation energy flux that are closely related to high-speed flows in the plasma sheet of the terrestrial magnetotail during both isolated and storm-time substorms. Here we further determine the plasma flow vorticity/shear and heating observed in the terrestrial magnetotail by the Magnetospheric Multiscale (MMS) mission by deducing that other energy may be dissipated along with the above-mentioned three energy releases. The energy transported by the flow is also estimated here. Three-dimensional observations have shown new detailed information that can be compared with quasi-2D simulations. In this investigation, we calculate vorticity/shear directly from simultaneous observation of four MMS satellites. Our results generally indicate that plasma heating or temperature enhancements are related to both the flow vorticity/shear and current density, but more strongly with flow vorticity/shear. This research suggests that the ubiquitous energy input from the solar wind can be used to estimate plasma heating or temperature enhancements in the absence of any process or phenomenon relating to explosive energy release in planetary magnetospheres

Oceanographic observations of eddies impacting the Prince Edward Islands, South Africa

The ecosystem of the isolated Prince Edward Islands, south of the African continent, is strongly impacted by ocean eddies that are associated with the eastward flowing Antarctic Circumpolar Current. Satellite altimetry has revealed that the archipelago lies in a region of enhanced eddy kinetic energy. In the late 1990s it became apparent that in order to understand the influence of these eddies on the islands' ecosystem, the source, trajectory and nature of these eddies needed to be studied and understood. To this end a special research project with a strong ocean-going component was designed, the DEIMEC (Dynamics of Eddy Impact on Marion's ECosystem) programme. In this review we focus on the physical oceanography and summarize the aims, the results and the successes of this South African research initiative. In the vicinity of the Prince Edward Islands, an average of three intense well-defined eddies is observed per year. Their advection speeds are of the order of a few kilometres per day and longevities of 7-11 months. These features, of c. 100 km in diameter and reaching depths of at least 1000 m, transport anomalous water masses across the Polar Frontal Zone

Identifying the magnetotail lobes with Cluster magnetometer data

We describe a novel method for identifying times when a spacecraft is in Earth’s magnetotail lobes solely using magnetometer data. We propose that lobe intervals can be well identified as times when the magnetic field is strong and relatively invariant, defined using thresholds in the magnitude of BX and the standard deviation σ of the magnetic field magnitude. Using data from the Cluster spacecraft at downtail distances greater than 8 RE during 2001–2009, we find that thresholds of 30 nT and 3.5 nT, respectively, optimize agreement with a previous, independently derived lobe identification method that used both magnetic and plasma data over the same interval. Specifically, our method has a moderately high accuracy (66%) and a low probability of false detection (11%) in comparison to the other method. Furthermore, our method identifies the lobe on many other occasions when the previous method was unable to make any identification and yields longer continuous intervals in the lobe than the previous method, with intervals at the 90th percentile being triple the length. Our method also allows for analyses of the lobes outside the time span of the previous method

On the Relative Strength of Electric and Magnetic ULF Wave Radial Diffusion During the March 2015 Geomagnetic Storm

In this paper, we study electron radial diffusion coefficients derived from Pc4‐Pc5 ultralow frequency (ULF) wave power during the intense geomagnetic storm on 17–18 March 2015. During this storm the population of highly relativistic electrons was depleted within 2 hr of the storm commencement. This radial diffusion, depending upon the availability of source populations, can cause outward radial diffusion of particles and their loss to the magnetosheath, or inward transport and acceleration. Analysis of electromagnetic field measurements from Geostationary Operational Environment Satellite (GOES), Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite, and ground‐based magnetometers shows that the main phase storm‐specific radial diffusion coefficients do not correspond to statistical estimates. Specifically, during the main phase, the electric diffusion ( urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0001) is reduced, and the magnetic diffusion ( urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0002) is increased, compared to empirical models based on Kp. Contrary to prior results, the main phase magnetic radial diffusion cannot be neglected. The largest discrepancies, and periods of dominance of urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0003 over urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0004, occur during intervals of strongly southward IMF. However, during storm recovery, both magnetic and electric diffusion rates are consistent with empirical estimates. We further verify observationally, for the first time, an energy coherence for both urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0005 and urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0006 where diffusion coefficients do not depend on energy. We show that, at least for this storm, properly characterizing main phase radial diffusion, potentially associated with enhanced ULF wave magnetopause shadowing losses, cannot be done with standard empirical models. Modifications, associated especially with southward IMF, which enhance the effects of urn:x-wiley:jgra:media:jgra54863:jgra54863-math-0007 and introduce larger main phase outward transport losses, are needed

An empirical investigation into the propensity of reckless decision making within the high pressure environment of Deal or No Deal.

This paper discusses human attitudes towards risk and the development of expected utility models, laying the foundations for the creation of prospect theory in 1979. It proceeds to analyse the decisions of contestants on the popular TV game show Deal or No Deal to attempt to observe any evidence of differing levels of risk aversion under losses and gains as predicted by prospect theory. The results reveal some evidence of decreased risk aversion in the domains of losses and gains, with contestants displaying behaviour consistent with the break-even and house-money effects. We conclude there may be enough evidence of variable reference points to warrant further investigation, and propose suggestions for further researc

An empirical investigation into the propensity of reckless decision making within the high pressure environment of Deal or No Deal.

This paper discusses human attitudes towards risk and the development of expected utility models, laying the foundations for the creation of prospect theory in 1979. It proceeds to analyse the decisions of contestants on the popular TV game show Deal or No Deal to attempt to observe any evidence of differing levels of risk aversion under losses and gains as predicted by prospect theory. The results reveal some evidence of decreased risk aversion in the domains of losses and gains, with contestants displaying behaviour consistent with the break-even and house-money effects. We conclude there may be enough evidence of variable reference points to warrant further investigation, and propose suggestions for further researc