Approaches to clerodane natural products

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Black Hole Motion as Catalyst of Orbital Resonances

The motion of a black hole about the centre of gravity of its host galaxy induces a strong response from the surrounding stellar population. We treat the case of a harmonic potential analytically and show that half of the stars on circular orbits in that potential shift to an orbit of lower energy, while the other half receive a positive boost and recede to a larger radius. The black hole itself remains on an orbit of fixed amplitude and merely acts as a catalyst for the evolution of the stellar energy distribution function f(E). We show that this effect is operative out to a radius of approx 3 to 4 times the hole's influence radius, R_bh. We use numerical integration to explore more fully the response of a stellar distribution to black hole motion. We consider orbits in a logarithmic potential and compare the response of stars on circular orbits, to the situation of a `warm' and `hot' (isotropic) stellar velocity field. While features seen in density maps are now wiped out, the kinematic signature of black hole motion still imprints the stellar line-of-sight mean velocity to a magnitude ~18% the local root mean-square velocity dispersion sigma.Comment: revised version, typos fixed, added references, 20 pages MN styl

The Orbital Structure of Triaxial Galaxies with Figure Rotation

We survey the properties of all orbit families in the rotating frame of a family of realistic triaxial potentials with central supermassive black holes (SMBHs). In such galaxies, most regular box orbits (vital for maintaining triaxiality) are associated with resonances which occupy two-dimensional surfaces in configuration space. For slow figure rotation all orbit families are largely stable. At intermediate pattern speeds a significant fraction of the resonant box orbits as well as inner long-axis tubes are destabilized by the "envelope doubling" that arises from the Coriolis forces and are driven into the destabilizing center. Thus, for pattern rotation periods .2 Gyr < Tp < 5 Gyr, the two orbit families that are most important for maintaining triaxiality are highly chaotic. As pattern speed increases there is also a sharp decrease in the overall fraction of prograde short-axis tubes and a corresponding increase in the retrograde variety. At the highest pattern speeds (close to that of triaxial bars), box-like orbits undergo a sudden transition to a new family of stable retrograde loop-like orbits, which resemble orbits in three-dimensional bars, and circulate about the short axis. Our analysis implies that triaxial systems (with central cusps and SMBHs) can either have high pattern speeds like fast bars or low patten speeds like triaxial elliptical galaxies or dark matter halos found in N-body simulations. Intermediate pattern speeds produce a high level of stochasticity in both the box and inner long-axis tube orbit families implying that stable triaxial systems are unlikely to have such pattern speeds.Comment: Version accepted for publication in ApJ, Vol 727, Feb. 1 issue, 201

A Thirst for Empire: How Tea Shaped the Modern World

(First paragraph) In A Thirst for Empire: How Tea Shaped the Modern World, Erika Rappaport, specialist in British consumer culture, explores the influ- ence of the quintessential English beverage on the rise of mass markets and British identity. Drawing from a variety of research tradi- tions, including recent commodity studies, the author argues that tea was both a product of and a producer of empire. The commercial success of tea created powerful corporate entities with imperial ties, such as the English East India Company and Lipton’s. But, it was the practice of drinking tea that defined and transformed “Britishness.” Tea came to represent a civilizing force that brought together the mul- tiethnic and multinational aspects of Great Britain, connecting the homeland to its colonial peripheries of Africa, South Asia, and North America and illuminating “the intimate and social experience of impe- rialism,” even while maintaining inherent racial, gendered, and class hierarchies (p. 17)

Tea Trade, Consumption, and the Republican Paradox in Prerevolutionary Philadelphia

Discusses the politics of the tea trade and tea consumption in late colonial Philadelphia, Pennsylvania, through the views of tea merchants and political radicals in America. The emergence of global trade had stripped tea of its luxury status, as its price continually dropped over the early 18th century. Smuggled tea from Dutch sources lowered prices further, enabling many to boycott British tea without hardship. Tea merchants decried the boycott for economic reasons while boycott leaders sought to gain the moral high ground by re-infusing tea with luxury status. Such was the status when the 1773 Tea Act placed a small tax on English East India Company tea that was discounted below the price of smuggled tea, precipitating a confrontation between American republicanism and economic self-interest

Spear Phishing Attack Detection

This thesis addresses the problem of identifying email spear phishing attacks, which are indicative of cyber espionage. Spear phishing consists of targeted emails sent to entice a victim to open a malicious file attachment or click on a malicious link that leads to a compromise of their computer. Current detection methods fail to detect emails of this kind consistently. The SPEar phishing Attack Detection system (SPEAD) is developed to analyze all incoming emails on a network for the presence of spear phishing attacks. SPEAD analyzes the following file types: Windows Portable Executable and Common Object File Format (PE/COFF), Adobe Reader, and Microsoft Excel, Word, and PowerPoint. SPEAD\u27s malware detection accuracy is compared against five commercially-available email anti-virus solutions. Finally, this research quantifies the time required to perform this detection with email traffic loads emulating an Air Force base network. Results show that SPEAD outperforms the anti-virus products in PE/COFF malware detection with an overall accuracy of 99.68% and an accuracy of 98.2% where new malware is involved. Additionally, SPEAD is comparable to the anti-virus products when it comes to the detection of new Adobe Reader malware with a rate of 88.79%. Ultimately, SPEAD demonstrates a strong tendency to focus its detection on new malware, which is a rare and desirable trait. Finally, after less than 4 minutes of sustained maximum email throughput, SPEAD\u27s non-optimized configuration exhibits one-hour delays in processing files and links