135 research outputs found
Cochlear implantation of a Hungarian deaf and blind patient with discharging ears suffering from Behçet's disease
A case is reported in which a Nucleus 22 channel intracochlear device was implanted a deaf/blind Hungarian adult with discharging ears suffering from Behçet's disease. Preconditioning surgery was employed three months prior to the implantation procedure to ensure a sterile, dry protected environment for the electrodes. One month after implantation, the patient exhibited excellent auditory discrimination capability at the time of the first switch on. We suggest that some deaf/blind individuals may serve as very good candidates for intracochlear implantatio
Parametrically excited surface waves: Two-frequency forcing, normal form symmetries, and pattern selection
Motivated by experimental observations of exotic standing wave patterns in the two-frequency Faraday experiment, we investigate the role of normal form symmetries in the pattern selection problem. With forcing frequency components in ratio m/n, where m and n are co-prime integers, there is the possibility that both harmonic and subharmonic waves may lose stability simultaneously, each with a different wavenumber. We focus on this situation and compare the case where the harmonic waves have a longer wavelength than the subharmonic waves with the case where the harmonic waves have a shorter wavelength. We show that in the former case a normal form transformation can be used to remove all quadratic terms from the amplitude equations governing the relevant resonant triad interactions. Thus the role of resonant triads in the pattern selection problem is greatly diminished in this situation. We verify our general results within the example of one-dimensional surface wave solutions of the Zhang-Vinals model of the two-frequency Faraday problem. In one-dimension, a 1:2 spatial resonance takes the place of a resonant triad in our investigation. We find that when the bifurcating modes are in this spatial resonance, it dramatically effects the bifurcation to subharmonic waves in the case of forcing frequencies are in ratio 1/2; this is consistent with the results of Zhang and Vinals. In sharp contrast, we find that when the forcing frequencies are in ratio 2/3, the bifurcation to (sub)harmonic waves is insensitive to the presence of another spatially-resonant bifurcating mode
Quasi-Specific Factors: Worker Comparative Advantage in the Two-Sector Production Model
This paper integrates the Heckscher-Ohlin, specific-factors, and Ricardian models of production with applications to international trade and labor economics. In international trade, factors of production need not be divided over trade policy and factor price equalization need not prevail. In labor economics, we show that the earning of economic rents is not inconsistent with competitive markets in general equilibrium and that process and skill-based innovations have contrasting effects on wage inequality. While the ratio of skilled to unskilled wages was rising sharply in the United States during the 1980
Assessing External Effects of City Airports: Land Values in Berlin
This paper employs a hedonic price model to explain standard land values in Berlin. Impact on land values is assessed for the two city airports situated in Berlin, Germany, Tempelhof and Tegel. Empirical results confirm expectations about the impact of various attributes on land values. Areas exposed to noise pollution of downtown airport Tempelhof sell at a discount of approximately 5-9% within a distance of 5000 m along the air corridor. No significantly negative impact was found for land values around Tegel Airport, which is located in a central, but less densely populated, area. Market access indicators created for all three Berlin airports in operation, including Berlin Schoenefeld International Airport, reveal clear location advantages in terms of accessibility of Tempelhof and Tegel compared to Schoenefeld Airport, where the new Berlin Brandenburg International Airport is about to be developed
Reinvigorating Springfield’s Economy: Lessons from Resurgent Cities
As part of the Federal Reserve Bank of Boston's commitment to supporting efforts to revitalize the economy of Springfield, Massachusetts, this paper analyzes the economic development approaches of other mid-sized manufacturing-oriented cities during the past half century. From among a comparison group of 25 municipalities that were similar to Springfield in 1960, the study identifies 10 'resurgent cities' that have made substantial progress in improving living standards for their residents, and that are recognized as vital communities in a broader sense by experts on urban economic development and policy. These case studies suggest that industry mix, demographic composition, and geographic position are not the key factors distinguishing the resurgent cities from Springfield. Instead, the most important lessons from the resurgent cities concern leadership and collaboration. Initial leadership in these cities came from a variety of key institutions and individuals. In some cases, the turnaround started with efforts on the part of the public sector, while in other cases nongovernmental institutions or private developers were at the forefront. Regardless of who initiated the turnaround, economic redevelopment efforts spanned decades and involved collaborations among numerous organizations and sectors
Does urban sprawl increase the costs of providing local public services? Evidence from Spanish municipalities
This paper examines the impact of urban sprawl, a phenomenon of particular interest in Spain, which is currently experiencing this process of rapid, low-density urban expansion. Many adverse consequences are attributed to urban sprawl (e.g., traffic congestion, air pollution and social segregation), though here we are concerned primarily with the rising costs of providing local public services. Our initial aim is to develop an accurate measure of urban sprawl so that we might empirically test its impact on municipal budgets. Then, we undertake an empirical analysis using a cross-sectional data set of 2,500 Spanish municipalities for the year 2003 and a piecewise linear function to account for the potentially nonlinear relationship between sprawl and local costs. The estimations derived from the expenditure equations for both aggregate and six disaggregated spending categories indicate that low-density development patterns lead to greater provision costs of local public services
Effectiveness of regional innovation actions: cases from small, low-innovative regions
This paper attempts to identify the suitability of centrally designed innovation-related regional actions, examining the case of regions that started innovative activities from a low development level. Using the case of two Greek regions, the paper analyses the legacy left to the regional systems by a series of regional innovation programmes implemented during the 1990s and 2000s, whose main priorities were designed centrally without any regional consultation. The findings suggest that these programmes often provide the means for generating the first steps towards the creation of a Regional Innovation System; however often they create a dependency on publicly funded programmes
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