602 research outputs found

    The Syntax of the Double Modal Construction

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    This paper looks at a problem in syntactic -variation, the syntax of the so-called double modal constructions in Southern United States English. Its purpose is to clarify the analysis of DMs and to consider its implications for some current proposals concerning adverbials and negation. The framework of the analysis presupposes that grammars have a core and a periphery, and the analysis attempts to account for both relevant syntactic properties of DMs and their idiosyncratic nature by treating the extra ('spurious') modal as licensed by an extension of the mechanism that licenses adverbs. In addition, the analysis supports C. L. Baker's view that the ordering of negatives is part of the periphery by extending Baker's analysis to DM constructions

    Curve counting in genus one: Elliptic singularities and relative geometry

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    We construct and study the reduced, relative, genus one Gromov-Witten theory of very ample pairs. These invariants form the principal component contribution to relativeGromov-Witten theory in genus one and are relative versions of Zinger's reduced Gromov-Witten invariants. We relate the relative and absolute theories by degeneration of the tangency conditions, and the resulting formulas generalise a well-known recursive calculation scheme put forward by Gathmann in genus zero. The geometric input is a desingularisation of the principal component of the moduli space of genus one logarithmic stable maps to a very ample pair, using the geometry of elliptic singularities. Our study passes through general techniques for calculating integrals on logarithmic blowups of moduli spaces of stable maps, which may be of independent interest

    ICT for Social Inclusion and Equal Opportunities: CETI-D, an e-Governance Good Practice in Brazil

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    In this chapter we discuss a Knowledge Economy based approach to the inclusion of persons with disabilities (PwD) that, different from the traditional \u201cassistance\u201d model, considers PwD as active and valuable members of the present Knowledge Society, to be included in the active workforce. This approach will be discussed with reference to a specific operational case study concerning the establishment of the Center of Excellence for Technology and Innovation in Favor of Persons with Disabilities (CETI-D) conceived by Fondazione Rosselli Americas and being implemented by the State of Sao Paulo in Brazil. In the first section of the chapter we discuss the problem of the inclusion of PwD as a further aspect of the digital divide phenomenon. In the second section the principles of the United Nation Convention on the Rights of Persons with Disabilities are presented and some international best practices concerning the social inclusion of PwD are introduced. In the third section we discuss the CETI-D initiative, with the aim of showing how ICT can represent a powerful tool for social and economic inclusion. Finally, in the fourth section we discuss the conditions under which the experience of the CETI-D can be replicated in other countries, with a specific focus on less developed countries

    Sustainable Business Models of SMEs: Challenges in Yacht Tourism Sector

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    Despite the high number of active small and medium enterprises (SMEs) in all sectors, current studies have barely developed investigations on the sustainability of their business models so far. The aim of this study was thus to bridge the gap between sustainable business models of SMEs in the service industry, to uncover the challenges that SMEs face when seeking business model reconfiguration toward sustainability. More specifically, the empirical investigation adopted a case study research design in the context of yacht tourism, as one business form among many within the tourism industry and thus within the broader category of the service industry. Interviews were conducted with seven European SMEs, whose business models were analyzed through the lens of the triple bottom line and sustainability challenges in their business models. The results display a varied typology of case studies, where business model components reveal diverse expressions of facing sustainability challenges. The work discusses reported findings with a cross-case comparison among detected business models and outlines a list of propositions for sustainable business models of SMEs. The paper contributes in continuing the discourse on sustainable business models, adopting the perspective of the challenges for SMEs and offers food for thought for managers of SMEs in comparing their own business with the identified business model types

    Non-linear Isolator for Vibration and Force Transmission Control of Unbalanced Rotating Machines

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    Purpose: The objective of this paper is to investigate with simulations how non-linear spring and non-linear damper components of isolators can be employed to effectively reduce both the oscillations and the force transmitted to ground in the whole spinning range of unbalanced rotating machines. Methods: The principal goal of this paper is twofold. First, to present a concise and consistent formulation based on the harmonic balance approach for the vibration response of spinning machines mounted on linear/non-linear, softening/hardening, un-tensioned/pre-tensioned springs and linear/non-linear dampers. Second, to provide a comprehensive overview of the vibration and force transmission control with non-linear isolators specifically tailored to unbalanced machines. Results: The study has shown that, the best vibration isolation is provided by a pre-tensioned linear and cubic softening spring combined with a linear and negative quadratic damper. The pre-tensioned spring should be designed in such a way as it holds the weight of the machine and thus produces on the vibrating machine a symmetric elastic restoring force proportional to the linear and cubic powers of the displacement. The cubic softening stiffness should then be tuned to minimise the frequency, and thus the amplitude, of the resonant response of the fundamental mode of the machine and elastic suspension system, while preserving stability and a desired static deflection. In parallel, to reduce the force transmission to ground above the fundamental resonance frequency, the negative quadratic damping effect should be tailored to maximize the energy absorption at higher frequencies. Conclusion: The study has shown that non-linear spring and non-linear damper components can be effectively employed to control the vibration and force transmission in the whole spinning range of the machine. In particular, a pre-tensioned softening cubic non-linear spring can be used to mitigate the vibration and force transmission at low frequencies, close to the fundamental natural frequencies of the elastically suspended machine. Also, a negative quadratic non-linear damper can be used to tailor the energy dissipation of the isolator in such a way as to have high damping at low frequencies and low damping at higher frequencies, which enhances the vibration and force transmission control at low frequencies and, rather importantly, mitigates the force transmission at higher frequencies

    Field reliability of GaAs emitters for fiber optic telecommunication systems

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    GaAs based emitters are widely used in telecommunication systems, and will be probably the core of short haul communications, even if a lot of doubts still exist on their reliability and the few available field results are not too optimistic. For these reasons we decided to follow with a particular attention all the problems related to these devices, investigating reliability by means of accelerated tests and of an accurate survey of field troubles. In this paper, we first of all report our field data, coming from more than five years experience, which show that "reasonable" results (in the range of 2000 FITs for LDs), can be obtained with commercially available devices; as a second step, failure analysis allows to localize failures,thus understanding the appropriate corrective actions to be taken. highlighting the specific process report also same For chip related failures, detailed examples are reported, different failure mechanisms, that, when not related to defects, are the same found during accelerated tests; we examples of failures due to interconnections and packaging

    Virtual classes for the working mathematician

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    This note is intended to be a friendly introduction to virtual classes. We review virtual classes and we give a number of properties and applications. We also include a new virtual push-forward theorem and many computations of virtual classes in simple examples

    Reduced invariants from cuspidal maps

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    We consider genus one enumerative invariants arising from the Smyth-Viscardi moduli space of stable maps from curves with nodes and cusps. We prove that these invariants are equal to the reduced genus one invariants of the quintic threefold, providing a modular interpretation of the latter

    In Vitro Selection of Single-Stranded DNA Molecular Recognition Elements against S. aureus Alpha Toxin and Sensitive Detection in Human Serum

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    Alpha toxin is one of the major virulence factors secreted by Staphylococcus aureus, a bacterium that is responsible for a wide variety of infections in both community and hospital settings. Due to the prevalence of S. aureus related infections and the emergence of methicillin-resistant S. aureus, rapid and accurate diagnosis of S. aureus infections is crucial in benefiting patient health outcomes. In this study, a rigorous Systematic Evolution of Ligands by Exponential Enrichment (SELEX) variant previously developed by our laboratory was utilized to select a single-stranded DNA molecular recognition element (MRE) targeting alpha toxin with high affinity and specificity. At the end of the 12-round selection, the selected MRE had an equilibrium dissociation constant (Kd) of 93.7 ± 7.0 nM. Additionally, a modified sandwich enzyme-linked immunosorbent assay (ELISA) was developed by using the selected ssDNA MRE as the toxin-capturing element and a sensitive detection of 200 nM alpha toxin in undiluted human serum samples was achieved
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