64 research outputs found
Matrix Models and A Proof of the Open Analog of Witten’s Conjecture
No full textIn a recent work, R. Pandharipande, J. P. Solomon and the second author have initiated a study of the intersection theory on the moduli space of Riemann surfaces with boundary. They conjectured that the generating series of the intersection numbers satisfies the open KdV equations. In this paper we prove this conjecture. Our proof goes through a matrix model and is based on a Kontsevich type combinatorial formula for the intersection numbers that was found by the second author
The liquid-lithium target at the soreq applied research accelerator facility
No full textFranz Käppeler and collaborators showed in the 1980’s that the Li(p, n)Be reaction can be used to produce a flux of neutrons having a stellar-like energy distribution, closely similar to that contributing to the slow (s) neutron capture process in massive stars. The Liquid-Lithium Target (LiLiT) at Phase I of the Soreq Applied Research Accelerator Facility (SARAF) was designed following the same physical principle. Owing to the high proton beam intensity of SARAF and the power dissipation of LiLiT, the facility provided a neutron intensity more than one order of magnitude higher than available with conventional solid Li targets. We review here our first collaboration with Franz Käppeler and his group, the LiLiT design and nuclear astrophysics research accomplished in recent years at the SARAF-LiLiT facility. An outlook to the research program with SARAF Phase II, currently in construction, is presented
Large membranes structures for scientific remote sensing and space exploration
No full textAs part of the NASA Floyd L.Thompson Fellowship, the author spent four months in the beginning of 2005 at the International Center for Numerical Methods in Engineering (CIMNE) in Barcelona, Spain. During this visit, he had many opportunities to discuss the new NASA Space Exploration Program with graduate students and faculty at CIMNE, and worked closely with several researchers focusing on the modeling and analysis of thin-film membranes. Here, a brief overview of the space exploration technologies that use very large structural membranes is presented, together with some comments related to computational mechanics issues for simulating the response of large membrane structures
Refined open intersection numbers and the Kontsevich-Penner matrix model
No full textA study of the intersection theory on the moduli space of Riemann surfaces with boundary was recently initiated in a work of R. Pandharipande, J.P. Solomon and the third author, where they introduced open intersection numbers in genus 0. Their construction was later generalized to all genera by J.P. Solomon and the third author. In this paper we consider a refinement of the open intersection numbers by distinguishing contributions from surfaces with different numbers of boundary components, and we calculate all these numbers. We then construct a matrix model for the generating series of the refined open intersection numbers and conjecture that it is equivalent to the Kontsevich-Penner matrix model. An evidence for the conjecture is presented. Another refinement of the open intersection numbers, which describes the distribution of the boundary marked points on the boundary components, is also discussed
Adapting authoritarianism: institutions and co-optation in Egypt and Syria
No full textThis PhD thesis compares Egypt and Syria’s authoritarian political systems. While the tendency in social science political research treats Egypt and Syria as similarly authoritarian, this research emphasizes differences between the two systems with special reference to institutions and co-optation. Rather than reducibly understanding Egypt and Syria as sharing similar histories, institutional arrangements, or ascribing to the oft-repeated convention that “Syria is Egypt but 10 years behind,” this thesis focuses on how events and individual histories shaped each states current institutional strengthens and weaknesses. Specifically, it explains the how varying institutional politicization or de-politicization affects each state’s capabilities for co-opting elite and non-elite individuals.
Beginning with a theoretical framework that considers the limited utility of democratization and transition theoretical approaches, the work underscores the persistence and durability of authoritarianism. Chapter two details the politicized institutional divergence between Egypt and Syria that began in the 1970s. Chapter three and four examines how institutional politicization or de-politicization affects elite and non-elite individual co-optation in Egypt and Syria. Chapter five discusses the study’s general conclusions and theoretical implications.
This thesis’s argument is that Egypt and Syria co-opt elites and non-elites differently because of the varying degrees of institutional politicization in each governance system. Rather than view one country as more politically developed than the other, this work argues that Syria’s political institutions are more politicized than their Egyptian counterparts. Syria’s political arena is, thus, described as politicized-patrimonialism. Syria’s politicized-patrimonial arena produces uneven co-optation of elites and non-elites as they are diffused through competing institutions. Conversely, the Egyptian political arena remains highly personalized as weak institutions and individuals are manipulated and molded according to the president’s ruling clique. This is referred to as personalized-patrimonialism. As a consequence, Egypt’s political establishment demonstrates more flexibility in ad hoc altering and adapting its arena depending on the emergence of crises.
This study’s theoretical implications suggest that, contrary to modernization and democratization theory’s adage that institutions lead to a political development, politicized institutions within a patrimonial order actually hinder regime adaptation because consensus is harder to achieve and maintain. It is within this context that Egypt’s de-politicized institutional framework advantages its top political elite. In this reading of Egyptian and Syrian politics, Egypt’s personalized political arena is more adaptable than Syria’s. These conclusions do not indicate that political reform is a process underway in either state
Open Saito Theory for A and D Singularities
No full textA well-known construction of B. Dubrovin and K. Saito endows the parameter space of a universal unfolding of a simple singularity with a Frobenius manifold structure. In our paper, we present a generalization of this construction for the singularities of types A and D that gives a solution of the open WDVV equations. For the A-singularity, the resulting solution describes the intersection numbers on the moduli space of r-spin disks, introduced recently in a work of the 2nd author, E. Clader and R. Tessler. In the 2nd part of the paper, we describe the space of homogeneous polynomial solutions of the open WDVV equations associated to the Frobenius manifolds of finite irreducible Coxeter groups
Extended r-spin theory and the mirror symmetry for the Ar–1-singularity
No full textBy a famous result of K. Saito, the parameter space of the miniversal deformation of the Ar−1Ar−1 singularity carries a Frobenius manifold structure. The Landau–Ginzburg mirror symmetry says that, in the flat coordinates, the potential of this Frobenius manifold is equal to the generating series of certain integrals over the moduli space of rr spin curves. In this paper we show that the parameters of the miniversal deformation, considered as functions of the flat coordinates, also have a simple geometric interpretation using the extended rr spin theory, first considered by T. J. Jarvis, T. Kimura and A. Vaintrob, and studied in a recent paper of E. Clader, R. J. Tessler and the author. We prove a similar result for the singularity D4D4 and present conjectures for the singularities E6E6 and E8E8
Evandro Affonso Ferreira: vidas desengraçadas e o arquivo debilitado
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-graduação em LiteraturaEsta dissertação investiga procedimentos da escritura de Evandro Affonso Ferreira, autor brasileiro contemporâneo com cinco livros publicados até o momento. Estes procedimentos são estudados a partir de como suas personagens se movem. O trabalho se divide em duas partes: a primeira é um jogo entre uma galeria (possível e falhada) de estúpidos e suas "vidas infames", acerca da experiência e da existência precárias dessas personagens. O jogo se dá num contágio com as artes visuais (Marcelo Coutinho, Elida Tessler e León Ferrari) e com alguns outros textos ficcionais de autores como Gusmán, Kafka, Melville, Walser etc. A segunda é como o autor trabalha com seus textos, seus livros e o léxico que usa - as palavras sonoras -, como se tudo isso formasse um só livro, livre numa biblioteca de babel da língua, da imaginação, da memória, da literatura. O livro como objeto que compõe a trajetória de um autor-leitor, a sua coleção babélica. Para isso faço uso de teóricos como Agamben, Benjamin, Blanchot, Derrida, Deleuze, Foucault entre outros. This dissertation investigates writing procedures by Evandro Affonso Ferreira, a contemporary Brazilian author with five books published so far. These procedures are studied according to the movement of the characters. The work is divided in two parts: the first one is a game for a galery (possible and failed) of stupids and its "infamous lives" regarding the precarious experience and existence of these characters. The game happens in an involvement with the visual arts (Marcelo Coutinho, Elida Tessler and León Ferrari) and with some other fictional texts from authors like Gusmán, Kafka, Melville, Walser etc. The second one is how the author works with his texts, books and the lexicon he uses - the sonorous words -, as all this would form a single (an unique) book, free in a Babel library of the language, of the imagination, of the memory, of the literature. The book as an object that compounds the trajectory of an author-reader, his Babelic collection. For this I use the theories of Agamben, Benjamin, Blanchot, Derrida, Deleuze, Foucault and others
Radiofrequency Schottky diodes based on p-doped copper(I) thiocyanate (CuSCN)
No full textSchottky diodes based on inexpensive materials that can be processed using simple manufacturing methods are of particular importance for the next generation of flexible electronics. Although a number of high-frequency n-type diodes and rectifiers have been demonstrated, the progress with p-type diodes is lagging behind, mainly due to the intrinsically low conductivities of existing p-type semiconducting materials that are compatible with low-temperature, flexible, substrate-friendly processes. Herein, we report on CuSCN Schottky diodes, where the semiconductor is processed from solution, featuring coplanar Al–Au nanogap electrodes (<15 nm), patterned via adhesion lithography. The abundant CuSCN material is doped with the molecular p-type dopant fluorofullerene C60F48 to improve the diode’s operating characteristics. Rectifier circuits fabricated with the doped CuSCN/C60F48 diodes exhibit a 30-fold increase in the cutoff frequency as compared to pristine CuSCN diodes (from 140 kHz to 4 MHz), while they are able to deliver output voltages of >100 mV for a VIN = ±5 V at the commercially relevant frequency of 13.56 MHz. The enhanced diode and circuit performance is attributed to the improved charge transport across CuSCN induced by C60F48. The ensuing diode technology can be used in flexible complementary circuits targeting low-energy-budget applications for the emerging internet of things device ecosystem
Multi-spectral investigation of bulk and facet failures in high-power single emitters at 980 nm
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