The Arab Spring

In this presentation, Dr. Ben Rich will discuss the arc of the Arab Spring of 2011 and the trends that emerged in the wake of this tumultuous event. Particular focus is given to the role of state responses during the protests and uprisings across the Middle East during this periods and the tendency of these regimes to both intensify their authoritarianism and promote a wide-ranging sectarianism that continues to have ramifications to this day

Managing Recreational Rivers

This paper will discuss various approaches that have \u27been or could be taken by government agencies in order to provide and protect rivers with recreational potential for use as public recreational facilities, in particular boating and canoeing, and consider them in the context of the state of Illinois, which has been faced with a tremendous increase in pressure for water based recreational facilities and anachronistic case and statute law of water and related land resources. The fundamental issue in any situation involving use by the public of natural watercourses concerns the concept of navigability. Crucial and divergent sets of conclusions follow -from a determination that a particular body of water is or is not navigable. There are, however, different definitions of navigability which must be applied depending upon the facts and issue at hand. Therefore, it is appropriate,. indeed. essential, .that this analysis begin with a thorough discussion of navigability

The Saudi State as an Identity Racketeer

Where substantial research has examined the Saudi state’s symbiosis with the Islamic revivalist movement commonly known as ‘Wahhabism’, little has considered how the dynamics of state formation underpin this relationship. This article argues that a continuous and circular political logic sits behind the Saudi state’s patronage of the revivalist movement since 1744. It proposes a four-stage model that explains how and why the Saudi state has maintained its support of the revivalist movement over this prolonged period. This article will first outline this model, before moving to a detailed analysis of the development of Saudi state authority to highlight the recurrent manner in which the spiritual concerns of revivalists have often been constructed by the state to counter challenges to its authority, a pattern showcased most recently during the Arab Spring and the war in Yemen. The relevance of this model persists today, and will continue to shape the decisions, policies and perceptions of the Saudi political elite for the foreseeable future

A Backend Framework for the Efficient Management of Power System Measurements

Increased adoption and deployment of phasor measurement units (PMU) has provided valuable fine-grained data over the grid. Analysis over these data can provide insight into the health of the grid, thereby improving control over operations. Realizing this data-driven control, however, requires validating, processing and storing massive amounts of PMU data. This paper describes a PMU data management system that supports input from multiple PMU data streams, features an event-detection algorithm, and provides an efficient method for retrieving archival data. The event-detection algorithm rapidly correlates multiple PMU data streams, providing details on events occurring within the power system. The event-detection algorithm feeds into a visualization component, allowing operators to recognize events as they occur. The indexing and data retrieval mechanism facilitates fast access to archived PMU data. Using this method, we achieved over 30x speedup for queries with high selectivity. With the development of these two components, we have developed a system that allows efficient analysis of multiple time-aligned PMU data streams.Comment: Published in Electric Power Systems Research (2016), not available ye

The chemical abundances in the Galactic Centre from the atmospheres of Red Supergiants

The Galactic Centre (GC) has experienced a high degree of recent star-forming activity, as evidenced by the large number of massive stars currently residing there. The relative abundances of chemical elements in the GC may provide insights into the origins of this activity. Here, we present high-resolution $H$-band spectra of two Red Supergiants in the GC (IRS~7 and VR~5-7), and in combination with spectral synthesis we derive abundances for Fe and C, as well as other $\alpha$-elements Ca, Si, Mg Ti and O. We find that the C-depletion in VR~5-7 is consistent with the predictions of evolutionary models of RSGs, while the heavy depletion of C and O in IRS~7's atmosphere is indicative of deep mixing, possibly due to fast initial rotation and/or enhanced mass-loss. Our results indicate that the {\it current} surface Fe/H content of each star is slightly above Solar. However, comparisons to evolutionary models indicate that the {\it initial} Fe/H ratio was likely closer to Solar, and has been driven higher by H-depletion at the stars' surface. Overall, we find $\alpha$/Fe ratios for both stars which are consistent with the thin Galactic disk. These results are consistent with other chemical studies of the GC, given the precision to which abundances can currently be determined. We argue that the GC abundances are consistent with a scenario in which the recent star-forming activity in the GC was fuelled by either material travelling down the Bar from the inner disk, or from the winds of stars in the inner Bulge -- with no need to invoke top-heavy stellar Initial Mass Functions to explain anomalous abundance ratios.Comment: 23 pages, 5 figs. Accepted for publication in Ap

Peculiar Multimodality on the Horizontal Branch of the Globular Cluster NGC 2808

We present distributions of colors of stars along the horizontal branch of the globular cluster NGC 2808, from Hubble Space Telescope WFPC2 imaging in B, V, and an ultraviolet filter (F218W). This cluster's HB is already known to be strongly bimodal, with approximately equal-sized HB populations widely separated in the color-magnitude diagram. Our images reveal a long blue tail with two gaps, for a total of four nearly distinct HB groups. These gaps are very narrow, corresponding to envelope-mass differences of only \sim 0.01 Msun. This remarkable multimodality may be a signature of mass-loss processes, subtle composition variations, or dynamical effects; we briefly summarize the possibilities. The existence of narrow gaps between distinct clumps on the HB presents a challenge for models that attempt to explain HB bimodality or other peculiar HB structures.Comment: LaTeX, including compressed figures. To appear in ApJL. Larger (851k) PostScript version, including high-quality figures, available from http://astro.berkeley.edu/~csosin/pub