Making War: The President and Congress

The main aim of this dissertation was to investigate the difference in neural language patternsrelated to language ability in healthy adults. The focus lies on unraveling the contributions of theright‐hemispheric homologues to Broca’s area in the inferior frontal gyrus (IFG) and Wernicke’s areain the posterior temporal and inferior parietal lobes. The functions of these regions are far from fullyunderstood at present. Two study populations consisting of healthy adults and a small group ofpeople with generalized epilepsy were investigated. Individual performance scores in tests oflanguage ability were correlated with brain activation obtained with functional magnetic resonanceimaging during semantic and word fluency tasks. Performance‐dependent differences were expectedin the left‐hemispheric Broca’s and Wernicke’s area and in their right‐hemispheric counterparts. PAPER I revealed a shift in laterality towards right‐hemispheric IFG and posterior temporal lobeactivation, related to high semantic performance. The whole‐brain analysis results of PAPER IIrevealed numerous candidate regions for language ability modulation. PAPER II also confirmed thefinding of PAPER I, by showing several performance‐dependent regions in the right‐hemispheric IFGand the posterior temporal lobe. In PAPER III, a new study population of healthy adults was tested.Again, the right posterior temporal lobe was related to high semantic performance. A decrease in lefthemisphericIFG activation could be linked to high word fluency ability. In addition, task difficultywas modulated. Increased task complexity showed to correlate positively with bilateral IFGactivation. Lastly, PAPER IV investigated anti‐correlated regions. These regions are commonly knownas the default mode network (DMN) and are normally suppressed during cognitive tasks. It wasfound that people with generalized epilepsy had an inadequate suppression of regions in the DMN,and showed poorer performance in a complex language test. The results point to neural adaptabilityin the IFG and temporal lobe. Decreased left‐lateralization of the IFG and increased rightlateralizationof the posterior temporal lobe are proposed as characteristics of individuals with highlanguage ability

What Happened to the Soviet Superpower’s Nuclear Arsenal? Clues for the Nuclear Security Summit

Twenty years ago Russia and fourteen other newly-independent states emerged from the ruins of the Soviet empire, many as nations for the first time in history. As is typical in the aftermath of the collapse of an empire, this was followed by a period of chaos, confusion, and corruption. As the saying went at the time, “everything is for sale.” At that same moment, as the Soviet state imploded, 35,000 nuclear weapons remained at thousands of sites across a vast Eurasian landmass that stretched across eleven time zones. Today, fourteen of the fifteen successor states to the Soviet Union are nuclear weapons-free. When the U.S.S.R. disappeared, 3,200 strategic nuclear warheads remained in Ukraine, Kazakhstan, and Belarus, most of them atop intercontinental ballistic missiles (ICBMs) that stood on alert, ready to be fired at targets in the U.S. Today, every one of the nuclear weapons in Ukraine, Kazakhstan, and Belarus has been deactivated and returned to Russia, where they were dismantled and the nuclear material in the warheads blended down to produce fuel for civilian reactors. Strategic nuclear weapons are nuclear warheads aimed at an adversary’s nuclear weapons, cities and military infrastructure. Typically, they are large in yield and heavy. Of greater interest to terrorists, however, were the former U.S.S.R’s 22,000 tactical nuclear weapons with smaller yields and shorter ranges. These were designed primarily for battlefield use, with some small enough to fit into a duffel bag. Today, all of these have also been returned to Russia, leaving zero nuclear weapons in any other state of the former Soviet Union. Former Czech president Vaclav Havel observed about the rush of events in the 1990s: “things have changed so fast we have not yet taken time to be astonished.” Perhaps the most astonishing fact about the past twenty years is something that did not happen. Despite the risk realistically estimated by former Secretary of Defense Dick Cheney in 3 What Happened to the Soviet Superpower's Nuclear Arsenal? Clues for the Nuclear Security Summit December 1991, two decades have passed without the discovery of a single nuclear weapon outside Russia. This paper will address the question: how did this happen? Looking ahead, it will consider what clues we can extract from the success in denuclearizing fourteen post-Soviet states that can inform our non-proliferation and nuclear security efforts in the future. These clues may inform leaders of the U.S., Russia, and other responsible nations attending the Seoul Nuclear Security Summit on March 26-27, 2012. The paper will conclude with specific recommendations, some exceedingly ambitious that world leaders could follow to build on the Seoul summit’s achievements against nuclear terrorism in the period before the next summit in 2014. One of these would be to establish a Global Alliance Against Nuclear Terrorism

An ultra-weak sector, the strong CP problem and the pseudo-Goldstone dilaton

In the context of a Coleman-Weinberg mechanism for the Higgs boson mass, we address the strong CP problem. We show that a DFSZ-like invisible axion model with a gauge-singlet complex scalar field S, whose couplings to the Standard Model are naturally ultra-weak, can solve the strong CP problem and simultaneously generate acceptable electroweak symmetry breaking. The ultra-weak couplings of the singlet S are associated with underlying approximate shift symmetries that act as custodial symmetries and maintain technical naturalness. The model also contains a very light pseudo-Goldstone dilaton that is consistent with cosmological Polonyi bounds, and the axion can be the dark matter of the universe. We further outline how a SUSY version of this model, which may be required in the context of Grand Unification, can avoid introducing a hierarchy problem.Comment: 9 page

Ultra-weak sector, Higgs boson mass, and the dilaton

The Higgs boson mass may arise from a portal coupling to a singlet field $\sigma$ which has a very large VEV $f \gg m_\text{Higgs}$. This requires a sector of "ultra-weak" couplings $\zeta_i$, where $\zeta_i \lesssim m_\text{Higgs}^2 / f^2$. Ultra-weak couplings are technically naturally small due to a custodial shift symmetry of $\sigma$ in the $\zeta_i \rightarrow 0$ limit. The singlet field $\sigma$ has properties similar to a pseudo-dilaton. We engineer explicit breaking of scale invariance in the ultra-weak sector via a Coleman-Weinberg potential, which requires hierarchies amongst the ultra-weak couplings.Comment: 6 page

L’essence de la décision. Le modèle de l’acteur rationnel

Introduction A quelle méthode pouvons-nous recourir lorsque nous sommes confrontés à un événement sur la scène internationale dont la logique nous échappe ? Penchons-nous par exemple sur cette question : « Comment expliquer l’installation par les Soviétiques de missiles à Cuba ? ». La plupart des chercheurs en science politique, ainsi d’ailleurs que la plupart des citoyens, commenceront par envisager les différents buts que les Soviétiques pouvaient avoir à l’esprit, tels que, sonder les int..

Low-threshold room temperature polariton lasing from fluorene-based oligomers

The authors are grateful to the Australian Research Council (ARC DP160100700 and DP200103036), Australian Department of Industry, Innovation and Science (AISRF53765), the UK Engineering and Physical Sciences Research Council (Grants EP/M025330/1 and EP/L017008/1), China Scholarship Council and the Rank Prize Funds for financial support.Organic semiconductors possessing tightly bound Frenkel excitons are known to be attractive candidates for demonstrating polariton lasing at room temperature. As polariton lasing can occur without inversion, it is a potential route to very low threshold coherent light sources. However, so far, the thresholds of organic polariton lasers have generally been much higher than those of organic photon lasers. Here this problem has been addressed by investigating two new organic molecules with a structure combining fluorene and carbazole groups. The materials are readily deposited from solution and exhibit high photoluminescence quantum yields, high absorption coefficients, and large radiative decay rates in neat films. Room temperature polariton lasing is realized in both materials with incident thresholds of 13.5 and 9.7 µJ cm−2, corresponding to absorbed thresholds of 3.3 and 2.2 µJ cm−2, respectively. These are the lowest values reported to date for polariton lasing in organic semiconductor materials, and approach typical values for organic photon lasers. The step-like power dependent blue-shift of polariton modes indicates an interplay between different depletion channels of the exciton reservoir. This work brings practical room temperature polaritonic devices and future realization of electrically driven polariton lasers a step closer.Publisher PDFPeer reviewe

Habitat continuity and geographic distance predict population genetic differentiation in giant kelp

Isolation by distance (IBD) models are widely used to predict levels of genetic connectivity as a function of Euclidean distance, and although recent studies have used GIS-landscape ecological approaches to improve the predictability of spatial genetic structure, few if any have addressed the effect of habitat continuity on gene flow. Landscape effects on genetic connectivity are even less understood in marine populations, where habitat mapping is particularly challenging. In this study, we model spatial genetic structure of a habitat-structuring species, the giant kelp Macrocystis pyrifera, using highly variable microsatellite markers. GIS mapping was used to characterize habitat continuity and distance between sampling sites along the mainland coast of the Santa Barbara Channel, and their roles as predictors of genetic differentiation were evaluated. Mean dispersal distance (σ) and effective population size (Ne) were estimated by comparing our IBD slope with those from simulations incorporating habitat continuity and spore dispersal characteristics of the study area. We found an allelic richness of 7–50 alleles/locus, which to our knowledge is the highest reported for macroalgae. The best regression model relating genetic distance to habitat variables included both geographic distance and habitat continuity, which were respectively, positively and negatively related to genetic distance. Our results provide strong support for a dependence of gene flow on both distance and habitat continuity and elucidate the combination of Ne and σ that explained genetic differentiation