Ministerial influence on the machinery of government: insights on the Inside

The structure and organisation of the machinery of government is key to theambitions of political coalitions. When portfolio allocation and agencificationare a function of political choice, political volatility should also affect internalstructure of government administrations. This study tests the effects of politicalturnover of individual ministers and of the political ideology of coalitionson a dataset of intra-ministerial changes in Dutch ministries between 1980and 2014. Findings indicate that the turnover of political heads of departmentsand the shifts in policy preferences between successive coalitionsindeed affects the internal structure of ministerial departments. Political variableshave a strong impact, particularly changes in the left–right position ofthe government. A clear pattern for how precisely politics affect the structuraldesign of public organisations remains absent, in spite of the robustness ofthe findings. Most ministries experience significant effect of executive turnover,sometimes increasing the hazards of intra-organisational transitions andsometimes increasing stability. It turns out that ministers can substantially rearrangetheir organisations in line with their policy preferences but do notnecessarily do so. Sometimes the effect of liberal ideology dominates, sometimesthe effect of the policy preferences with respect to a specificdomain prevails.NWOORASecurity and Global AffairsThe politics and administration of institutional chang

Organizational Demography

The politics and administration of institutional chang

Exponential Metric Fields

The Laser Interferometer Space Antenna (LISA) mission will use advanced technologies to achieve its science goals: the direct detection of gravitational waves, the observation of signals from compact (small and dense) stars as they spiral into black holes, the study of the role of massive black holes in galaxy evolution, the search for gravitational wave emission from the early Universe. The gravitational red-shift, the advance of the perihelion of Mercury, deflection of light and the time delay of radar signals are the classical tests in the first order of General Relativity (GR). However, LISA can possibly test Einstein's theories in the second order and perhaps, it will show some particular feature of non-linearity of gravitational interaction. In the present work we are seeking a method to construct theoretical templates that limit in the first order the tensorial structure of some metric fields, thus the non-linear terms are given by exponential functions of gravitational strength. The Newtonian limit obtained here, in the first order, is equivalent to GR.Comment: Accepted for publication in Astrophysics and Space Science, 17 page

The 6D SuperSwirl

We present a novel supersymmetric solution to a nonlinear sigma model coupled to supergravity. The solution represents a static, supersymmetric, codimension-two object, which is different to the familiar cosmic strings. In particular, we consider 6D chiral gauged supergravity, whose spectrum contains a number of hypermultiplets. The scalar components of the hypermultiplet are charged under a gauge field, and supersymmetry implies that they experience a simple paraboloid-like (or 2D infinite well) potential, which is minimised when they vanish. Unlike conventional vortices, the energy density of our configuration is not localized to a string-like core. The solutions have two timelike singularities in the internal manifold, which provide the necessary boundary conditions to ensure that the scalars do not lie at the minimum of their potential. The 4D spacetime is flat, and the solution is a continuous deformation of the so-called ``rugby ball'' solution, which has been studied in the context of the cosmological constant problem. It represents an unexpected class of supersymmetric solutions to the 6D theory, which have gravity, gauge fluxes and hyperscalars all active in the background.Comment: 26 pages, 2 figures, JHEP3 class. Typos corrected, analysis expanded, references adde

Modified Gravity via Spontaneous Symmetry Breaking

We construct effective field theories in which gravity is modified via spontaneous breaking of local Lorentz invariance. This is a gravitational analogue of the Higgs mechanism. These theories possess additional graviton modes and modified dispersion relations. They are manifestly well-behaved in the UV and free of discontinuities of the van Dam-Veltman-Zakharov type, ensuring compatibility with standard tests of gravity. They may have important phenomenological effects on large distance scales, offering an alternative to dark energy. For the case in which the symmetry is broken by a vector field with the wrong sign mass term, we identify four massless graviton modes (all with positive-definite norm for a suitable choice of a parameter) and show the absence of the discontinuity.Comment: 5 pages; revised versio

Gauge Fields, Fermions and Mass Gaps in 6D Brane Worlds

We study fluctuations about axisymmetric warped brane solutions in 6D minimal gauged supergravity. Much of our analysis is general and could be applied to other scenarios. We focus on bulk sectors that could give rise to Standard Model gauge fields and charged matter. We reduce the dynamics to Schroedinger type equations plus physical boundary conditions, and obtain exact solutions for the Kaluza-Klein wave functions and discrete mass spectra. The power-law warping, as opposed to exponential in 5D, means that zero mode wave functions can be peaked on negative tension branes, but only at the price of localizing the whole Kaluza-Klein tower there. However, remarkably, the codimension two defects allow the Kaluza-Klein mass gap to remain finite even in the infinite volume limit. In principle, not only gravity, but Standard Model fields could `feel' the extent of large extra dimensions, and still be described by an effective 4D theory.Comment: 33 pages, 2 figures; typesetting problem fixed ({\o}replaced by \omega

Entre la vie et la mort: le changement organisationnel dans les bureaucraties de l’État central dans une perspective comparative transnationale

Identifier et expliquer les changements dans la structure des bureaucraties de l’État central et les déterminants de la survie des organisations publiques individuelles sont deux domaines de recherche étroitement liés dans l’administration publique. Nous cherchons à combler le fossé entre ces deux principaux courants d’études du changement organisationnel en présentant une nouvelle approche de la collecte de données sur l’historique des événements pour les organisations publiques. Nous avons développé ce cadre dans le cadre du projet « Structure et organisation des gouvernements », qui vise à cartographier l’ensemble des bureaucraties de l’État central dans trois pays d’Europe occidentale. Notre approche est suffisamment flexible pour décrire les macro-tendances des populations d’organisations du secteur public et pour expliquer ces tendances en analysant l’histoire des événements des organisations qu’elles comprennent. En plus de présenter notre cadre et la manière dont nous l’avons appliqué pour créer cet ensemble de données, nous présentons également quelques premières comparaisons transnationales de la répartition des types d’événements enregistrés, et soulignons les premiers résultats et les pistes prometteuses pour des recherches ultérieures.NWOORA 464-13-113The politics and administration of institutional changeSecurity and Global Affair

Supersymmetric codimension-two branes in six-dimensional gauged supergravity

We consider the six-dimensional Salam-Sezgin supergravity in the presence of codimension-2 branes. In the case that the branes carry only tension, we provide a way to supersymmetrise them by adding appropriate localised Fayet-Iliopoulos terms and localised corrections to the Chern-Simons term and modifying accordingly the fermionic supersymmetry transformations. The resulting brane action has N=1 supersymmetry (SUSY). We find the axisymmetric vacua of the system and show that one has unwarped background solutions with "football"-shaped extra dimensions which always respect N=1 SUSY for any value of the equal brane tensions, in contrast with the non-supersymmetric brane action background. Finally, we generically find multiple zero modes of the gravitino in this background and discuss how one could obtain a single chiral zero mode present in the low energy spectrum.Comment: 21 pages, no figures, A sign error in the gauge potential at the lower brane corrected and its consequent effect discusse

Disappearing Dark Matter in Brane World Cosmology: New Limits on Noncompact Extra Dimensions

We explore cosmological implications of dark matter as massive particles trapped on a brane embedded in a Randall-Sundrum noncompact higher dimension $AdS_5$ space. It is an unavoidable consequence of this cosmology that massive particles are metastable and can disappear into the bulk dimension. Here, we show that a massive dark matter particle (e.g. the lightest supersymmetric particle) is likely to have the shortest lifetime for disappearing into the bulk. We examine cosmological constraints on this new paradigm and show that disappearing dark matter is consistent (at the 95% confidence level) with all cosmological constraints, i.e. present observations of Type Ia supernovae at the highest redshift, trends in the mass-to-light ratios of galaxy clusters with redshift, the fraction of X-ray emitting gas in rich clusters, and the spectrum of power fluctuations in the cosmic microwave background. A best $2 \sigma$ concordance region is identified corresponding to a mean lifetime for dark matter disappearance of $15 \le \Gamma^{-1} \le 80$ Gyr. The implication of these results for brane-world physics is discussed.Comment: 7 pages, 7 figures, new cosmological constraints added, accepted for publication in PR