3,807 research outputs found

    Zk\mathbb{Z}_k-stratifolds

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    Generalizing the ideas of Zk\mathbb{Z}_k-manifolds from Sullivan and the theory of stratifolds from Kreck, we define Zk\mathbb{Z}_k-stratifolds. We introduce the bordism theory of Zk\mathbb{Z}_k-stratifolds in order to represent every homology class with Zk\mathbb{Z}_k-coefficients. We present a geometric interpretation of the Bockstein long exact sequence and the Atiyah-Hirzebruch spectral sequence for Zk\mathbb{Z}_k-bordism (kk odd)

    String Theory Realizations of the Nilpotent Goldstino

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    We describe in detail how the spectrum of a single anti-D3-brane in four-dimensional orientifolded IIB string models reproduces precisely the field content of a nilpotent chiral superfield with the only physical component corresponding to the fermionic goldstino. In particular we explicitly consider a single anti-D3-brane on top of an O3-plane in warped throats, induced by (2,1)(2,1) fluxes. More general systems including several anti-branes and other orientifold planes are also discussed. This provides further evidence to the claim that non-linearly realized supersymmetry due to the presence of antibranes in string theory can be described by supersymmetric theories including nilpotent superfields. Implications to the KKLT and related scenarios of de Sitter moduli stabilization, to cosmology and to the structure of soft SUSY-breaking terms are briefly discussed.Comment: 33 pages, 8 figures. v2: reference added, minor change

    Employment promotion measures and the quality of the job match for persons with disabilities

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    We evaluate the influence that employment promotion measures and labour market intermediation services addressed to disabled individuals have on the latter’s quality of the job match through the use of matching analysis techniques. Our focus is placed on two aspects of quality: the type of contract held (either permanent or temporary) and whether or not the individual is searching for another job. We find that those measures do not improve the quality of the job match. Implications for labour market policy are discussed.Disability, job matching, employment promotion, evaluation, matching analysis, permanent contract, job-to-job search.

    A Framework for Strategic Sustainability in Organizations: A Three Pronged Approach

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    Sustainability has become an increasingly important strategic concept for organizations. The idea of sustainability is also starting to become ingrained in various managerial and organizational decisions. Sustainability in an organization is defined by its commitment to economic factors, environmental factors, and factors of social commitment in a firm. A framework is used to develop a strategic or long-term justification for the concept of sustainability. Also, this study attempts to extend the concept of sustainability and decision making to a global business environment. This study proposes a mission-driven management methodological framework that acts as a base for decision-making using the concept of international strategic sustainability. This contribution includes investigating the design and development of strategic sustainability and combining the relationships of organizational decision-making to economic, environmental, and social sustainability outcomes

    Neuro-fuzzy chip to handle complex tasks with analog performance

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    This paper presents a mixed-signal neuro-fuzzy controller chip which, in terms of power consumption, input–output delay, and precision, performs as a fully analog implementation. However, it has much larger complexity than its purely analog counterparts. This combination of performance and complexity is achieved through the use of a mixed-signal architecture consisting of a programmable analog core of reduced complexity, and a strategy, and the associated mixed-signal circuitry, to cover the whole input space through the dynamic programming of this core. Since errors and delays are proportional to the reduced number of fuzzy rules included in the analog core, they are much smaller than in the case where the whole rule set is implemented by analog circuitry. Also, the area and the power consumption of the new architecture are smaller than those of its purely analog counterparts simply because most rules are implemented through programming. The Paper presents a set of building blocks associated to this architecture, and gives results for an exemplary prototype. This prototype, called multiplexing fuzzy controller (MFCON), has been realized in a CMOS 0.7 um standard technology. It has two inputs, implements 64 rules, and features 500 ns of input to output delay with 16-mW of power consumption. Results from the chip in a control application with a dc motor are also provided

    The role of structural pleiotropy in the retention of protein complexes after gene duplication

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    La duplication de gènes est l’un des plus importants mécanismes évolutifs pour la génération de diversité fonctionelle. Lorsqu’un gène est dupliqué, la nouvelle copie partage toutes ses fonctions avec la copie ancestrale car elles encodent pour des protéines identiques. Donc, les deux protéines, appelées paralogues, auront le même réseau d’interactions physiques protéine-protéine. Cependant, dans le cas de la duplication des gènes qui codent des protéines qui interagissent avec elles-mêmes (homomères), la nouvelle protéine interagira aussi avec la copie ancestrale, ce qui introduit une nouvelle interaction (heteromère) (Kaltenegger and Ober, 2015; Pereira-Leal et al., 2007). Puisque ces interactions peuvent avoir des différents motifs de rétention et de fonction (Ashenberg et al., 2011; Baker et al., 2013; Boncoeur et al., 2012; Bridgham et al., 2008), il est important de mieux comprendre comment ces états sont atteints et quelles forces évolutives les favorisent. Dans ce memoire, je cible ces questions avec des simulations in silico de l’évolution des protéines suite à la duplication de gènes en travaillant avec des structures crystallographiques de haute qualité, provenant de la Protein Data Bank (Berman et al., 2000; Dey et al., 2018). Les simulations montrent que les sous-unités et interfaces partagées entraînent une forte corrélation entre les trajectoires évolutives de ces complexes. Ainsi, les simulations prédisent que la préservation de seulement les deux homomères ou seulement l’hétéromère ne devrait pas être fréquente. Toutefois, la simulation qui applique la sélection seulement sur un homomère montre que l’homomère neutre est destabilisé plus rapidement que l’hétéromère neutre. Nous avons comparé ces prédictions avec des résultats expérimentaux du réseau d’interactions protéine-protéine de la levure. Comme suggéré par les simulations, les patrons d’interactions les plus fréquents ont été la formation des trois complexes (deux homomères et un hétéromère) ou la formation de seulement un homomère. Les patrons correspondants à deux homomères sans hétéromères ou un hétéromère sans homomères sont rares. Nos résultats démontrent l’extension de l’hétéromérisation entre paralogues dans le réseau d’interactions physiques protéine-protéine de la levure, les mécanismes sous-jacents et ses implications.Gene duplication is one of the most important evolutionary mechanisms for the generation of functional diversity. When a gene is duplicated, the new copy shares all of the ancestral copy’s functions because they encode identical proteins. Therefore, the two proteins, called paralogs, will have the same protein-protein interaction network. However, in the case of the duplication of genes encoding proteins that self-interact (homomers), the new protein will also interact with the ancestral copy, introducing a novel interaction (heteromer) (Kaltenegger and Ober, 2015; Pereira-Leal et al., 2007). As these interactions can have different retention and functional patterns (Ashenberg et al., 2011; Baker et al., 2013; Boncoeur et al., 2012; Bridgham et al., 2008), it is important to understand better how these states are reached and what evolutionary forces favor each of them. In this thesis, I approach these questions by means of in silico simulations of protein evolution after gene duplication by working with high-quality crystal structures from the Protein Data Bank (Berman et al., 2000; Dey et al., 2018). The simulations show that the shared subunits and interfaces lead to these complexes having highly correlated evolutionary trajectories. Thus, the simulations predict that the preservation of only the two homomers or only the heteromer is not likely to happen often. Nevertheless, simulating evolution with selection on only one homomer shows that the neutral homomer is destabilized faster than the neutral heteromer. We compared these predictions against experimental results from the yeast protein-protein interaction network. As suggested by the simulations, the most abundant interaction patterns were either the formation of all three complexes (two homomers and one heteromer) or the formation of only one homomer, with motifs corresponding to two homomers without a heteromer or a heteromer without homomers being rare. Our results highlight the extent of heteromerization between paralogs in the yeast protein-protein interaction network, the underlying mechanisms, and its implication

    From perception to action and vice versa: a new architecture showing how perception and action can modulate each other simultaneously

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    Presentado en: 6th European Conference on Mobile Robots (ECMR) Sep 25-27, 2013 Barcelona, SpainArtificial vision systems can not process all the information that they receive from the world in real time because it is highly expensive and inefficient in terms of computational cost. However, inspired by biological perception systems, it is possible to develop an artificial attention model able to select only the relevant part of the scene, as human vision does. From the Automated Planning point of view, a relevant area can be seen as an area where the objects involved in the execution of a plan are located. Thus, the planning system should guide the attention model to track relevant objects. But, at the same time, the perceived objects may constrain or provide new information that could suggest the modification of a current plan. Therefore, a plan that is being executed should be adapted or recomputed taking into account actual information perceived from the world. In this work, we introduce an architecture that creates a symbiosis between the planning and the attention modules of a robotic system, linking visual features with high level behaviours. The architecture is based on the interaction of an oversubscription planner, that produces plans constrained by the information perceived from the vision system, and an object-based attention system, able to focus on the relevant objects of the plan being executed.Spanish MINECO projects TIN2008-06196, TIN2012-38079-C03-03 and TIN2012-38079-C03-02. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    A Modular Programmable CMOS Analog Fuzzy Controller Chip

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    We present a highly modular fuzzy inference analog CMOS chip architecture with on-chip digital programmability. This chip consists of the interconnection of parameterized instances of two different kind of blocks, namely label blocks and rule blocks. The architecture realizes a lattice partition of the universe of discourse, which at the hardware level means that the fuzzy labels associated to every input (realized by the label blocks) are shared among the rule blocks. This reduces the area and power consumption and is the key point for chip modularity. The proposed architecture is demonstrated through a 16-rule two input CMOS 1-ÎĽm prototype which features an operation speed of 2.5 Mflips (2.5Ă—10^6 fuzzy inferences per second) with 8.6 mW power consumption. Core area occupation of this prototype is of only 1.6 mm 2 including the digital control and memory circuitry used for programmability. Because of the architecture modularity the number of inputs and rules can be increased with any hardly design effort.This work was supported in part by the Spanish C.I.C.Y.T under Contract TIC96-1392-C02- 02 (SIVA)

    Assigning New Responsibilities for Undergraduate Students in the Design Process of UAV Platforms

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    Design and building of UAVs (for civil and military missions) is a field of actuation where the most important Universities, research Centers and Aeronautical designers have dedicated a lot of human effort. This paper describes a long research work carried out by a group of UPM professors who are currently coordinating the design and building of an Unmanned Aerial Vehicle (UAV) at the EUIT. Aeronáutica to synthesize the work done in the twelve years. We first focus with the validity of this experience as a means to develop some skills and to achieve some teaching competencies which will be essential for engineers in the 21st Century, according to the Bologna Process project Tuning. The second part presents the highlights of the project: all the features and stages of this engineering project, and the current moment of evolution in the process will be presented, together with a description of the main difficulties the project has undergone, as a global experience in engineering design and development
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