Vortex dipolar structures in a rigid model of the larynx at flow onset

Starting jet airflow is investigated in a channel with a pair of consecutive slitted constrictions approximating the true and false vocal folds in the human larynx. The flow is visualized using the Schlieren optical technique and simulated by solving the Navier-Stokes equations for an incompressible two-dimensional viscous flow. Laboratory and numerical experiments show the spontaneous formation of three different classes of vortex dipolar structures in several regions of the laryngeal profile under conditions that may be assimilated to those of voice onset.Fil: Chisari, Nora Elisa. University of Princeton; Estados Unidos. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Artana, Guillermo Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Sciamarella, D.. Centre National de la Recherche Scientifique; Franci

Modeling voice production with time-delay systems: the larynx tube

International audienceTime-delay systems (shortly, TDS) are also called systems with aftereffect or dead-time, hereditary systems, equations with deviating argument or differential-difference equations. In voice production, TDS play a role in voice-production modeling when source and tract are coupled allowing for delayed feedback on the vocal fold dynamics [2,3]. This work undertakes the incorporation of the larynx tube to this modeling scheme, following an approach inspired in the assimilation of the larynx tube to a Helmholtz resonator, introduced four decades ago to study the singing formant

International Coercion, Emulation and Policy Diffusion: Market-Oriented Infrastructure Reforms, 1977-1999

Why do some countries adopt market-oriented reforms such as deregulation, privatization and liberalization of competition in their infrastructure industries while others do not? Why did the pace of adoption accelerate in the 1990s? Building on neo-institutional theory in sociology, we argue that the domestic adoption of market-oriented reforms is strongly influenced by international pressures of coercion and emulation. We find robust support for these arguments with an event-history analysis of the determinants of reform in the telecommunications and electricity sectors of as many as 205 countries and territories between 1977 and 1999. Our results also suggest that the coercive effect of multilateral lending from the IMF, the World Bank or Regional Development Banks is increasing over time, a finding that is consistent with anecdotal evidence that multilateral organizations have broadened the scope of the “conditionality” terms specifying market-oriented reforms imposed on borrowing countries. We discuss the possibility that, by pressuring countries into policy reform, cross-national coercion and emulation may not produce ideal outcomes.http://deepblue.lib.umich.edu/bitstream/2027.42/40099/3/wp713.pd

Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Productive Development Policies in Jamaica

Jamaica seems to be a puzzling case for economic growth: despite the structural reforms implemented in the last three decades and adequate investment levels, real GDP per capita is roughly the same as in 1970. The disappointing performance of this economy suggests that productive development policies (PDPs), including first-generation reforms, have not been enough to create a better environment for productivity growth. This paper examines the PDPs in Jamaica and concludes that behind the paradox of high investment and low growth of this economy are the public debt trap and a highly distortive tax incentive structure to attract foreign direct investment (FDI) and promote exports. Although industrial policy is moving towards a more modern conceptual design, the old schemes seem politically difficult to dismantle

The Semantics of Governance: The Common Thread Running Through Corporate, Public, and Global Governance

This paper argues that the semantics of governance illustrates connections and provides a unifying view from which to understand much better its natural branches: corporate, public and global governance. In this regard, governance is presented from the point of view of a distinctive field of learning and practice. Further, three levels of analysis are carried out to drive the subject home. Firstly, it highlights the extent of corporate governance within an institutional framework, and also gives heed to some performance measurement devices: the governance index, the comparativeeconomics approach, and the governance slack model. Secondly, it frames the notion of public governance while due regard is given to the World Bank's methodology and the public governance wave of reforms in the 80s and 90s. Afterwards, the development goes further to handle the linkage among constituents, charters and representation, so as to later cope with the problems raised by accountability and reputational intermediaries. Thirdly, it addresses the semantics of global governance, country assessments and corporate governance in global settings