Ultra-compact optical auto-correlator based on slow-light enhanced third harmonic generation in a silicon photonic crystal waveguide

The ability to use coherent light for material science and applications is directly linked to our ability to measure short optical pulses. While free-space optical methods are well-established, achieving this on a chip would offer the greatest benefit in footprint, performance, flexibility and cost, and allow the integration with complementary signal processing devices. A key goal is to achieve operation at sub-Watt peak power levels and on sub-picosecond timescales. Previous integrated demonstrations require either a temporally synchronized reference pulse, an off-chip spectrometer, or long tunable delay lines. We report the first device capable of achieving single-shot time-domain measurements of near-infrared picosecond pulses based on an ultra-compact integrated CMOS compatible device, with the potential to be fully integrated without any external instrumentation. It relies on optical third-harmonic generation in a slow-light silicon waveguide. Our method can also serve as a powerful in-situ diagnostic tool to directly map, at visible wavelengths, the propagation dynamics of near-infrared pulses in photonic crystals.Comment: 20 pages, 6 figures, 38 reference

3D Magnetic Analysis of the CMS Magnet

The CMS magnetic system consists of a super-conducting solenoid coil, 12.5 m long and 6 m free bore diameter, and of an iron flux-return yoke, which includes the central barrel, two end-caps and the ferromagnetic parts of the hadronic forward calorimeter. The magnetic flux density in the center of the solenoid is 4 T. To carry out the magnetic analysis of the CMS magnetic system, several 3D models were developed to perform magnetic field and force calculations using the Vector Fields code TOSCA. The analysis includes a study of the general field behavior, the calculation of the forces on the coil generated by small axial, radial displacements and angular tilts, the calculation of the forces on the ferromagnetic parts, the calculation of the fringe field outside the magnetic system, and a study of the field level in the chimneys for the current leads and the cryogenic lines. A procedure to reconstruct the field inside a cylindrical volume starting from the values of the magnetic flux density on the cylinder surface is considered. Special TOSCA-GEANT interface tools have being developed to input the calculated magnetic field into the detector simulation package.Comment: 4 pages, 6 figures, 1 equation, 14 reference

"Outside, it is snowing": Experience and finitude in the nonrepresentational landscapes of Alain Robbe-Grillet

Copyright © 2008 PionRomanillos J L, 2008. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning D: Society and Space 26(5) 795 – 822 DOI: 10.1068/d6207This paper presents and explicates the anonymous and impersonal spatialities tentatively mapped in the novels of Alain Robbe-Grillet. Emerging from the kinds of landscapes and visualities articulated, these spatialities are at odds with the kind of anthropocentrism characteristic of phenomenological narratives of spatial experience that would start from an apparently stable human-subject position. It is argued that his body of literature dismantles the anthropocentric narratives and biographies that would produce in both the space of the world and the ‘phenomenological subject’ an unwarranted depth and naturalism. Importantly, and reflecting the theoretical turn towards the being of language, Robbe-Grillet questions the legitimacy of linguistic subjects to capture the spaces of the visible. As such, it is argued that his literature reflects an experience of the critiques of phenomenology. Importantly, this ‘critique’ goes hand in hand with the kinds of spatialities and landscapes that are rendered in the novels—the indefinite perspectives they open up, the paradoxical visualities they sustain or deny, and the disorientation they inject into the heart of spatial experience. These literary effects produce a nonanthropocentric and nonpersonal spatiality which, although contributing to an erasure of the ‘subject’, at the same time expose and open up a sociospatiality based on singularities, intensities, and finitude

Evidence of suppression of onchocerciasis transmission in the Venezuelan Amazonian focus.

BACKGROUND: The World Health Organization (WHO) has set goals for onchocerciasis elimination in Latin America by 2015. Most of the six previously endemic countries are attaining this goal by implementing twice a year (and in some foci, quarterly) mass ivermectin (Mectizan®) distribution. Elimination of transmission has been verified in Colombia, Ecuador and Mexico. Challenges remain in the Amazonian focus straddling Venezuela and Brazil, where the disease affects the hard-to-reach Yanomami indigenous population. We provide evidence of suppression of Onchocerca volvulus transmission by Simulium guianense s.l. in 16 previously hyperendemic Yanomami communities in southern Venezuela after 15 years of 6-monthly and 5 years of 3-monthly mass ivermectin treatment. METHODS: Baseline and monitoring and evaluation parasitological, ophthalmological, entomological and serological surveys were conducted in selected sentinel and extra-sentinel communities of the focus throughout the implementation of the programme. RESULTS: From 2010 to 2012–2015, clinico-parasitological surveys indicate a substantial decrease in skin microfilarial prevalence and intensity of infection; accompanied by no evidence (or very low prevalence and intensity) of ocular microfilariae in the examined population. Of a total of 51,341 S. guianense flies tested by PCR none had L3 infection (heads only). Prevalence of infective flies and seasonal transmission potentials in 2012–2013 were, respectively, under 1 % and 20 L3/person/transmission season. Serology in children aged 1–10 years demonstrated that although 26 out of 396 (7 %) individuals still had Ov-16 antibodies, only 4/218 (2 %) seropositives were aged 1–5 years. CONCLUSIONS: We report evidence of recent transmission and morbidity suppression in some communities of the focus representing 75 % of the Yanomami population and 70 % of all known communities. We conclude that onchocerciasis transmission could be feasibly interrupted in the Venezuelan Amazonian focus. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1313-z) contains supplementary material, which is available to authorized users

Four problems regarding representable functors

Let $R$, $S$ be two rings, $C$ an $R$-coring and ${}_{R}^C{\mathcal M}$ the category of left $C$-comodules. The category ${\bf Rep}\, ( {}_{R}^C{\mathcal M}, {}_{S}{\mathcal M} )$ of all representable functors ${}_{R}^C{\mathcal M} \to {}_{S}{\mathcal M}$ is shown to be equivalent to the opposite of the category ${}_{R}^C{\mathcal M}_S$. For $U$ an $(S,R)$-bimodule we give necessary and sufficient conditions for the induction functor $U\otimes_R - : {}_{R}^C\mathcal{M} \to {}_{S}\mathcal{M}$ to be: a representable functor, an equivalence of categories, a separable or a Frobenius functor. The latter results generalize and unify the classical theorems of Morita for categories of modules over rings and the more recent theorems obtained by Brezinski, Caenepeel et al. for categories of comodules over corings.Comment: 16 pages, the second versio

Lifting defects for nonstable K_0-theory of exchange rings and C*-algebras

The assignment (nonstable K_0-theory), that to a ring R associates the monoid V(R) of Murray-von Neumann equivalence classes of idempotent infinite matrices with only finitely nonzero entries over R, extends naturally to a functor. We prove the following lifting properties of that functor: (1) There is no functor F, from simplicial monoids with order-unit with normalized positive homomorphisms to exchange rings, such that VF is equivalent to the identity. (2) There is no functor F, from simplicial monoids with order-unit with normalized positive embeddings to C*-algebras of real rank 0 (resp., von Neumann regular rings), such that VF is equivalent to the identity. (3) There is a {0,1}^3-indexed commutative diagram D of simplicial monoids that can be lifted, with respect to the functor V, by exchange rings and by C*-algebras of real rank 1, but not by semiprimitive exchange rings, thus neither by regular rings nor by C*-algebras of real rank 0. By using categorical tools from an earlier paper (larders, lifters, CLL), we deduce that there exists a unital exchange ring of cardinality aleph three (resp., an aleph three-separable unital C*-algebra of real rank 1) R, with stable rank 1 and index of nilpotence 2, such that V(R) is the positive cone of a dimension group and V(R) is not isomorphic to V(B) for any ring B which is either a C*-algebra of real rank 0 or a regular ring.Comment: 34 pages. Algebras and Representation Theory, to appea

PRECISE SEMI-AUTOMATIC FIELD MAPPING IN THE SPLIT FIELD MAGNET OF THE ISR

Abstract The computer-controlled equipment for the magnetic measurements of the Split Field Magnet System of the CERN Intersecting Storage Rings is described. Three different measurement machines are necessary for the measurements of this large and complex magnet system. The strongly inhomogeneous field is measured to a precision of 1 0/00 of maximum field using Hall-plate assemblies. The final data treatment includes the smoothing out of the established scalar potential by solving the Laplace's equation from the conditions at the boundaries by means of relaxation. The threedimensional field map will be used for particle analysis. Effects of the SFM-field on the circulating ISR beams are evaluated and optimized

SOME ABSTRACT PROPERTIES OF SEMIGROUPS APPEARING IN SUPERCONFORMAL THEORIES

A new type of semigroups which appears while dealing with $N=1$ superconformal symmetry in superstring theories is considered. The ideal series having unusual abstract properties is constructed. Various idealisers are introduced and studied. The ideal quasicharacter is defined. Green's relations are found and their connection with the ideal quasicharacter is established.Comment: 11 page