Organized social complexity as an analytical problem - An introduction and explication

Systems analysis of organized social complexity in terms of independent variable

Efficient Trading Strategies

In this paper, we point out the role of anticomonotonicity in the characterization of efficient contingent claims, and in the measure of inefficiency size of financial strategies. Two random variables are said to be anticomonotonic if they move in opposite directions. We first provide necessary and sufficient conditions for a contingent claim to be efficient in markets, which might be with frictions in a quite general framework. We then compute a measure of inefficiency size for any contingent claim. We finally give several applications of these results, studying in particular the efficiency of superreplication strategies.anticomonotonicity, utility maximization, markets with frictions

Analysis by the Two-Fluids Model of the Dynamical Behavior of a Viscoelastic Fluid Probed by Dynamic Light Scattering

The dynamic properties of a model transient network have been studied by dynamic light scattering. The network is formed by microemulsion droplets linked by telechelic polymers (modified hydrophilic polymers with two grafted hydrophobic stickers). We compare the properties of two networks that are similar but for the residence time of the hydrophobic stickers in the droplets. The results are interpreted according to the so-called two-fluids model, which was initially developed for semidilute polymer solutions and which we extend here to any Maxwellian viscoelastic medium characterized by its elastic modulus and terminal time as measured by rheology. This model is found to describe consistently and quantitatively the experimental observations.Comment: novembre 200

The effect of interstitial clusters and vacancies on the STM image of graphite

Making use of the tight-binding Green's function technique, we have calculated the STM images of graphite with surface and sub-surface defects, while taking into account the relaxation of the lattice due to defects. We have demonstrated that two different physical mechanisms may result in the formation of hillocks in the STM images: buckling of the graphite surface due to interstitials between the uppermost graphite layers and the enhancement of the electron density of states close to the Fermi energy on the carbon atoms in the vicinity of vacancies. Our results indicate that small hillocks may originate both from the interstitial clusters and from the vacancies. By contrast, however, large hillocks in excess of 10 \AA~ in diameter can be caused only by interstitial clusters.Comment: Submitted to Surface Scienc

Self-Diffusion and Collective Diffusion of Charged colloids Studied by Dynamic Light Scattering

A microemulsion of decane droplets stabilized by a non-ionic surfactant film is progressively charged by substitution of a non-ionic surfactant molecule by a cationic surfactant. We check that the microemulsion droplets remain identical within the explored range of volume fraction (0.02 to 0.18) and of the number of charge per droplets (0 to 40) . We probe the dynamics of these microemulsions by dynamic light scattering. Despite the similar structure of the uncharged and charged microemulsions the dynamics are very different . In the neutral microemulsion the fluctuations of polarization relax, as is well known, via the collective diffusion of the droplets. In the charged microemulsions, two modes of relaxation are observed. The fast one is ascribed classically to the collective diffusion of the charged droplets coupled to the diffusion of the counterions. The slow one has, to our knowledge, not been observed previously neither in similar microemulsions nor in charged spherical colloids. We show that the slow mode is also diffusive and suggest that its possible origine is the relaxation of local charge fluctuations via local exchange of droplets bearing different number of charges . The diffusion coefficient associated with this mode is then the self diffusion coefficient of the droplets

Functional contributions of bootlegging and entrepreneurship in research organizations

Bootlegging and entrepreneurship by scientists in research organization

Micropillars with a controlled number of site-controlled quantum dots

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 112, 071101 (2018) and may be found at https://doi.org/10.1063/1.5017692.We report on the realization of micropillars with site-controlled quantum dots (SCQDs) in the active layer. The SCQDs are grown via the buried stressor approach which allows for the positioned growth and device integration of a controllable number of QDs with high optical quality. This concept is very powerful as the number and the position of SCQDs in the cavity can be simultaneously controlled by the design of the buried-stressor. The fabricated micropillars exhibit a high degree of position control for the QDs above the buried stressor and Q-factors of up to 12 000 at an emission wavelength of around 930 nm. We experimentally analyze and numerically model the cavity Q-factor, the mode volume, the Purcell factor, and the photon-extraction efficiency as a function of the aperture diameter of the buried stressor. Exploiting these SCQD micropillars, we experimentally observe a Purcell enhancement in the single-QD regime with FP = 4.3 ± 0.3.EC/FP7/615613/EU/External Quantum Control of Photonic Semiconductor Nanostructures/EXQUISITEDFG, SFB 787, Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

La diplomacia cultural americana: una apuesta por el recurso al poder blando

La mala imagen internacional de EEUU perjudica la política exterior y pone en riesgo su seguridad nacional. El Departamento de Estado, entre otras estrategias, ha recurrido a la diplomacia cultural para favorecer el entendimiento y difundir los valores democráticos. El integrismo islámico ha confirmado la influencia creciente de los valores culturales en la escena internacional. Aunque no es la única causa de su animosidad contra Occidente, es el argumento principal para justificar su particular guerra. Este nuevo contexto coincide con undeterioro de la imagen pública internacional de EEUU, provocada precisamente por los valores y la cultura que parecen inspirar su acción exterior. La situación pone en riesgo la seguridad de EEUU: alimenta la amenaza constante del terrorismo islamista y dificulta el respaldo de Europa, su tradicional aliado. El Departamento de Estado está revisando las estrategias de la diplomacia pública para comunicar con mayor eficacia sus principios políticos e idiosincrasia cultural. Este ARI recoge las reformas que están siendo introducidas y los términos en que se desarrolla el debate interno actual. El cambio puede ser significativo para la diplomacia internacional porque recupera como contenido prioritario los valores culturales