Thermal and kinematic corrections to the microwave background polarization induced by galaxy clusters along the line of sight

We derive analytic expressions for the leading-order corrections to the polarization induced in the cosmic microwave background (CMB) due to scattering off hot electrons in galaxy clusters along the line of sight. For a thermal distribution of electrons with a kinetic temperature of 10 keV and a bulk peculiar velocity of 1000 km/s, the dominant corrections to the polarization induced by the primordial CMB quadrupole and the cluster peculiar velocity arise from electron thermal motion and are at the level of 10 per cent in each case, near the peak of the polarization signal. When more sensitive measurements become feasible, these effects will be significant for the determination of transverse peculiar velocities, and the value of the CMB quadrupole at the cluster redshift, via the cluster polarization route.Comment: 7 pages, 2 figures. Version accepted for MNRAS. Minor expansion of text in some section

An Analysis of Jitter and Transit Timing Variations in the HAT-P-13 System

If the two planets in the HAT-P-13 system are coplanar, the orbital states provide a probe of the internal planetary structure. Previous analyses of radial velocity and transit timing data of the system suggested that the observational constraints on the orbital states were rather small. We reanalyze the available data, treating the jitter as an unknown MCMC parameter, and find that a wide range of jitter values are plausible, hence the system parameters are less well constrained than previously suggested. For slightly increased levels of jitter ($\sim 4.5\,m\,s^{-1}$) the eccentricity of the inner planet can be in the range $0<e_{inner}<0.07$, the period and eccentricity of the outer planet can be $440<P_{outer}<470$ days and $0.55<e_{outer}<0.85$ respectively, while the relative pericenter alignment, $\eta$, of the planets can take essentially any value $-180^{\circ}<\eta<+180^{\circ}$. It is therefore difficult to determine whether $e_{inner}$ and $\eta$ have evolved to a fixed-point state or a limit cycle, or to use $e_{inner}$ to probe the internal planetary structure. We perform various transit timing variation (TTV) analyses, demonstrating that current constraints merely restrict $e_{outer}<0.85$, and rule out relative planetary inclinations within $\sim 2^{\circ}$ of $i_{rel}=90^{\circ}$, but that future observations could significantly tighten the restriction on both these parameters. We demonstrate that TTV profiles can readily distinguish the theoretically favored inclinations of i_{rel}=0^{\circ}\,&\,45^{\circ}, provided that sufficiently precise and frequent transit timing observations of HAT-P-13b can be made close to the pericenter passage of HAT-P-13c. We note the relatively high probability that HAT-P-13c transits and suggest observational dates and strategies.Comment: Published in Ap

COIN is dead - long live transformation

Donald Rumsfeld was right. Force transformation works. The techniques that led to the initial victories in Afghanistan in 2001 were precisely those that produced success in Libya in 2011.1 Small-scale deployments of special forces backed by precision strike and deep attack capabilities used to support an allied indigenous armed group proved an effective military tool for achieving specific strategic outcomes. In contrast, the results of large-scale troop deploy- ments as part of counterinsurgency (COIN), stabilization and nation-building activities over the past ten years in Iraq and Afghanistan have been less defini- tive. Despite intensive investment in blood, treasure, and military effort, the precise long-term outcomes of these two campaigns remain unclear and will be open to debate for years to come. This challenging operational experience has, however, highlighted some necessary and enduring truths about the use of military force. This paper explores those in light of the last ten years of counterinsurgenc

The epistemology of lethality: bullets, knowledge trajectories, kinetic effects

The science of ammunition lethality is a field that seeks to define the point at which military ordnance takes life and produces death. By historicising lethality's epistemology, I reveal the intellectual fissures and scientific uncertainties that have been reified and embedded into contemporary conceptions of military power. This not only tells us something about the processes by which science is subordinated to war, but also offers a new lens from which to consider the way knowledge claims about battle are co-constructed and legitimated through military practices. As a result, this article places science back into a narrative that otherwise frames the ontology of war in terms of fighting

Marksmanship, officer-man relations and the Short Magazine Lee-Enfield

This article examines the British Army’s decision to adopt the Short Magazine Lee-Enfield (SMLE) in 1903. Historians invariably assume that this weapon was developed in response to demands to modernise and improve the Army following the failures and poor marksmanship of British soldiers fighting in the Boer War. Understood this way the SMLE’s selection appears inevitable and as a result is rarely examined in close detail. This stands in contrast to the wealth of attention dedicated to exploring how the cavalry fought to hold onto the arme blanche despite the apparent revolution in machinegun and artillery firepower. Upon closer examination, however, neither way of thinking about the changes occurring to the British Army after the Boer War does justice to the complexities surrounding the development and selection of the SMLE. Rather, by considering the manner in which different communities within the Army thought about battle, and in particular how engagements on the North West Frontier shaped perspectives on marksmanship, this article demonstrates how the Cavalry and the Indian Army played an important part in the adoption of the SMLE

Matthew Ford\u27s diet: An Application of the Diet Problem

Linear Programming has its origins in the 1940\u27s, when complex planning problems needed to be solved to contribute to the wartime operations. The Diet Problem was one of those problems. My project deals with the formulation of my own diet problem tailored to my personal tastes where I minimize the cost of eating for one week while maintaining a healthy diet. I gathered data for different meals as well as nutritional information such as calorie count and number of servings. The formulation was eventually modified to introduce variety into the diet

Outside The Lines: Exploring Student Use of Web-Based Vicarious Learning About Financial Markets

This study considers web-based expert commentary as a mechanism for college student learning about financial markets. Social cognitive theory suggests that students may team vicariously by observing the thought processes expressed in the writings of well chosen web-based role models and adopting similar patterns of thought over time. An exploratory study using undergraduate business school students investigated the change in measures of financial market awareness after exposure to web-based commentary. Significant learning effects were evident, particularly when exposure was augmented by structure that guided the learning experience. Although more research is required, these findings suggest the utility of web-based expert commentary for learning vicariously at the collegiate level

Studies of event shape observables with the OPAL detector at LEP

In quark-antiquark pair production at LEP, many features of the hadronic final state can be predicted by QCD. Using data collected by the OPAL experiment, we present the statistical distributions of fourteen "event shape observables," which describe the inclusive kinematic properties of events producing three or more jets. For six of these observables, we compare the measured distributions with those calculated in perturbative QCD. By optimising the agreement between theory and data, we measure the strong coupling $\alpha_s$ at a range of energy scales. We also test the predictions of three Monte Carlo event generators, for all fourteen observables. Over the years since the LEP experiments began operating, many similar analyses have been published, and have contributed to the world average measurements of $\alpha_s$. However, several improvements have now been made, both in the theoretical calculations and in the experimental analysis techniques. We therefore present a complete reanalysis of the OPAL data, over the full range of LEP collision energies. Particular attention is given to the estimation of uncertainties, including the large contribution due to uncalculated higher-order terms of the theory predictions. In collaboration with the LEP QCD Working Group, we have combined the $\alpha_s$ measurements obtained from event shape observables by all four experiments. Detailed investigations were undertaken to ensure consistent implementation of the theoretical predictions and uncertainty estimates, and to take account of correlations between measurements.Comment: 344 pages, 116 figures, latex2e, Ph.D. thesis, University of Cambridge, U.K. (also available in other formats at http://cern.ch/mtford/thesis

Using Transit Timing Observations to Search for Trojans of Transiting Extrasolar Planets

Theoretical studies predict that Trojans are likely a frequent byproduct of planet formation and evolution. We examine the sensitivity of transit timing observations for detecting Trojan companions to transiting extrasolar planets. We demonstrate that this method offers the potential to detect terrestrial-mass Trojans using existing ground-based observatories. We compare the transit timing variation (TTV) method with other techniques for detecting extrasolar Trojans and outline the future prospects for this method.Comment: submitted to ApJL, 12 pages, 2 figure