International Aid and Urban Change

The presence of expatriate humanitarian workers in African cities is not neutral. Country capitals receive large and sudden influx of expatriates during humanitarian crises responses. This book examines the influence of this presence on the local urban ecosystem, from the building of a security discourse to the self-segregation of aid agencies in expatriate enclaves. The examples of Abidjan, Bamako, Juba and Nairobi illustrate different variants of urban change induced by the normative power of aid organisations

International Aid and Urban Change

The presence of expatriate humanitarian workers in African cities is not neutral. Country capitals receive large and sudden influx of expatriates during humanitarian crises responses. This book examines the influence of this presence on the local urban ecosystem, from the building of a security discourse to the self-segregation of aid agencies in expatriate enclaves. The examples of Abidjan, Bamako, Juba and Nairobi illustrate different variants of urban change induced by the normative power of aid organisations

Estimates of multipolar coefficients to search for cosmic ray anisotropies with non-uniform or partial sky coverage

We study the possibility to extract the multipolar moments of an underlying distribution from a set of cosmic rays observed with non-uniform or even partial sky coverage. We show that if the degree is assumed to be upper bounded by $L$, each multipolar moment can be recovered whatever the coverage, but with a variance increasing exponentially with the bound $L$ if the coverage is zero somewhere. Despite this limitation, we show the possibility to test predictions of a model without any assumption on $L$ by building an estimate of the covariance matrix seen through the exposure function.Comment: 20 pages, 8 figure

NAMA: A GIS-based Network-analysis Approach for Mine Action

To demonstrate the potential of geographic information system (GIS) network-analysis tools in mine action, a hypothetical case study uses these tools to examine the distance survivors of mine incidents must travel for medical and rehabilitative care in one region in Colombia and suggests a location for a new facility

Whither do the microlensing Brown Dwarfs rove?

The EROS and MACHO collaborations have reported observations of light curves of stars in the Large Magellanic Cloud that are compatible with gravitational microlensing by intervening massive objects, presumably Brown-Dwarf stars. The OGLE and MACHO teams have also seen similar events in the direction of the galactic Bulge. Current data are insufficient to decide whether the Brown-Dwarfs are dark-matter constituents of the non-luminous galactic Halo, or belong to a more conventional population, such as that of faint stars in the galactic Spheroid, in its Thin or Thick Disks, or in their possible LMC counterparts. We discuss in detail how further observations of microlensing rates and of the moments of the distribution of event durations, can help resolve the issue of the Brown-Dwarf location, and eventually provide information on the mass function of the dark objects

The Sino-Korean influence on Middle Korean vowel harmony: A usage-based perspective

While Early Middle Korean (EMK) exhibited highly productive vowel harmony, including harmony within word stems and harmonic alternations for many of its case particles, these rules have become less productive and applicable to fewer phonological contexts from Late Middle Korean (LMK) onward. Language-internal changes have been correctly identified as one motivator for these rule reductions, yet the role of the extensive Sino-Korean lexicon in sound changes in LMK has not been thoroughly explored. Recent work in usage-based functionalism indicates that speakers infer and ultimately construct the rules of their language by inferring patterns from their accumulated linguistic data and experiences. It is argued here that as the local schema of non-harmonic Sino-Korean loans grew in prominence, these loans began to interfere with native speakers' inference of earlier harmonic rules, and said rules were relaxed; Sino-Korean loans were not merely exceptions to existing harmonic rules but catalysts of broader harmonic change

On the Onset of Coherent Phonon Motion in Peierls-Distorted Antimony by Attosecond Transient Absorption

Attosecond extreme-ultraviolet (XUV) transient absorption spectroscopy measurements on the Peierls-distorted phase of the semimetal antimony (Sb) are presented. After excitation by an ultrashort, broad band near-infrared (NIR) pulse, the distortion is (partly) lifted causing the well-known coherent phonon motion of the lattice. While the overall observed dynamics generally follow a displacive excitation model, a delayed onset of the pump-induced carrier dynamics due to hot-carrier thermalization is observed, as well as a large spectral phase dependence in the coherent phonon oscillation. The observed spectral phase dependence in the coherent motion is attributed to significantly different carrier relaxation timescales for carrier energies above and near the Fermi level of the semimetal. A simple theoretical model is presented that considers the carrier relaxation timescales in the displacive phonon model to explain the observed dynamics. The results conclusively show that the overall displacive motion is not solely due to an abrupt displacement of carriers from their equilibrium configuration by the pump pulse and that carrier-relaxation effects need to be considered in the description of the phonon motion. The results furthermore show an effect of NIR field-driven shifts of band-energies, which is observed as a transient reshaping of the core-level absorption features.Comment: 12 pages, 7 figures, 1 tabl

Force-induced denaturation of RNA

We describe quantitatively a RNA molecule under the influence of an external force exerted at its two ends as in a typical single-molecule experiment. Our calculation incorporates the interactions between nucleotides by using the experimentally-determined free energy rules for RNA secondary structure and models the polymeric properties of the exterior single-stranded regions explicitly as elastic freely-jointed chains. We find that in spite of complicated secondary structures, force-extension curves are typically smooth in quasi-equilibrium. We identify and characterize two sequence/structure-dependent mechanisms that, in addition to the sequence-independent entropic elasticity of the exterior single-stranded regions, are responsible for the smoothness. These involve compensation between different structural elements on which the external force acts simultaneously, and contribution of suboptimal structures, respectively. We estimate how many features a force-extension curve recorded in non-equilibrium, where the pulling proceeds faster than rearrangements in the secondary structure of the molecule, could show in principle. Our software is available to the public through a `RNA-pulling server'.Comment: final version (with a few minor changes) as will be published in Biophysical Journa

Vacuum decay along supersymmetric flat directions

It has been recently realized that within the Minimal Supersymmetric Standard Model, for certain patterns of superpartner masses, consistent with all the present experimental constraints, the scalar potential may develop at some scale $Q_0$ unbounded color/charge breaking directions involving the sfermion fields, and that these patterns are then excluded unless some new physics is invoked at or below the scale $Q_0$. We reanalyze this observation and point out that such patterns of superpartner masses at the weak scale are {\it not} ruled out when taking into account the probability of decay for the metastable color conserving minimum along these color breaking unbounded directions. It turns out that the color conserving minimum, although metastable, has a lifetime longer than the present age of the Universe and can survive both quantum tunneling and the effects of high temperatures in the early Universe, causing the color/charge breaking effects to be in practice not dangerous.Comment: 12 pages, uuencoded latex file + 4 ps figure