Nanotechnology and cancer

The biological picture of cancer is rapidly advancing from models built from phenomenological descriptions to network models derived from systems biology, which can capture the evolving pathophysiology of the disease at the molecular level. The translation of this (still academic) picture into a clinically relevant framework can be enabling for the war on cancer, but it is a scientific and technological challenge. In this review, we discuss emerging in vitro diagnostic technologies and therapeutic approaches that are being developed to handle this challenge. Our discussion of in vitro diagnostics is guided by the theme of making large numbers of measurements accurately, sensitively, and at very low cost. We discuss diagnostic approaches based on microfluidics and nanotechnology. We then review the current state of the art of nanoparticle-based therapeutics that have reached the clinic. The goal of the presentation is to identify nanotherapeutic strategies that are designed to increase efficacy while simultaneously minimizing the toxic side effects commonly associated with cancer chemotherapies

Propagation-invariant beams with quantum pendulum spectra: from Bessel beams to Gaussian beam-beams

We describe a new class of propagation-invariant light beams with Fourier transform given by an eigenfunction of the quantum mechanical pendulum. These beams, whose spectra (restricted to a circle) are doubly-periodic Mathieu functions in azimuth, depend on a field strength parameter. When the parameter is zero, pendulum beams are Bessel beams, and as the parameter approaches infinity, they resemble transversely propagating one-dimensional Gaussian wavepackets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an operator which interpolates between the squared angular momentum operator and the linear momentum operator. The analysis reveals connections with Mathieu beams, and insight into the paraxial approximation.Comment: 4 pages, 3 figures, Optics Letters styl

Perfect Competition, Spatial Competition, and Tax Incidence in the Retail Gasoline Market - Brief

This report uses monthly gas price data for all 50 U.S. states over the period 1984-1999 to examine the incidence of state gasoline excise taxes. FRC Brief 11

Perfect Competition, Spatial Competition, and Tax Incidence in the Retail Gasoline Market

This report uses monthly gas price data for all 50 U.S. states over the period 1984-1999 to examine the incidence of state gasoline excise taxes. FRC Report 11

The Relationship Between Task Cohesion and Competitive State Anxiety

The general purpose of the present study was to determine if perceptions of team cohesion are related to the interpretation athletes attach to their precompetition anxiety. Specifically examined was the association between athlete perceptions of task cohesiveness (Individual Attractions to the Group–Task, ATG-T, and Group Integration–Task, GI-T) and the degree to which perceptions of the intensity of precompetition anxiety symptoms (cognitive and somatic) were viewed as facilitative versus debilitative. Participants were athletes (N = 392) from the sports of soccer, rugby, and field hockey. Each athlete completed the Group Environment Questionnaire (Carron, Widmeyer, & Brawley, 1985) after a practice session. A directionally modified version of the Competitive State Anxiety Inventory-2 (Martens, Burton, Vealey, Bump, & Smith, 1990) was completed just prior to a competition. Results showed that athletes who perceived their cognitive anxiety as facilitative had higher perceptions of both ATG-T and GI-T, χ2 (2, N = 260) = 8.96, p \u3c .05, than athletes who perceived their cognitive anxiety as debilitative. Also, athletes who perceived their somatic anxiety as facilitative had higher perceptions of GI-T, χ2 (2, N = 249) = 5.85, p \u3c .05

Size rationalization and trade exposure in developing countries

Given the lack of direct evidence regarding industrial adjustment in response to trade liberalization, this paper tackles some very basic questions. Specifically, in LDCs, how is trade orientation correlated with the size distribution of plants and with plant-level labor productivity? It begins with a simple model that summarizes some effects of trade exposure on producer size and productive efficiency that have been stressed in the recent analytical and simulation literature. It then examines annual plant-level data from Chile and Colombia to determine whether these effects can be confirmed. The empirical results indicate that, over the long run, higher trade exposure is correlated with smaller plant sizes, controlling for industry and country effects. However, the mix of high versus low productivity plants is not strongly associated with trade exposure. Both of these findings cast doubt on the mechanisms linking trade, plant size, and productivity in a number of recent analytical and simulation studies.Economic Theory&Research,Environmental Economics&Policies,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade Policy,Science Education

An empirical model of sunk costs and the decision to export

Exports respond unpredictably to a change in real exchange rates, suggests evidence from the 1980s. Recent theoretical work explains this as a consequence of the sunk costs associated with breaking into foreign markets. Sunk costs include the cost of packaging, upgrading product quality, establishing marketing channels, and accumulating information on demand sources. The authors use micro panel data to estimate a dynamic discrete-choice model of participation in export markets, a model derived from the Krugman-Baldwin sunk-cost hysteresis framework. Applying the model to data on manufacturing plants in Colombia (1981-89), they test for the presence of sunk entry costs and quantify the importance of those costs in explaining export patterns. The econometric results reject the hypothesis that sunk costs are zero. The results, which control for both observed and unobserved sources of plant heterogeneity, indicate that prior export market experience has a substantial effect on the probability of exporting, but its effect depreciates fairly quickly. The reentry costs of plants that have been out of the export market for a year are substantially lower than the costs of a first-time exporter. After a year out of the export market, however, the reentry costs are not significantly different from the entry costs. Plant characteristics are also associated with export behavior: large old plants owned by corporations are more likely to export than other plants. Variations in plant-level cost and demand conditions have much less effect on the profitability of exporting than variations in macroeconomic conditions and sunk costs do. It appears especially difficult to break into foreign markets during periods of world recession.Economic Theory&Research,Markets and Market Access,Environmental Economics&Policies,Decentralization,Water Conservation,Environmental Economics&Policies,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Markets and Market Access,Access to Markets

Real Exchange Rates Over the Past Two Centuries : How Important is the Harrod-Balassa-Samuelson Effect?

Using data since 1820 for the US, the UK and France, we test for the presence of real effects on the equilibrium real exchange rate (the Harrod-Balassa-Samuelson, HBS effect) in an explicitly nonlinear framework and allowing for shifts in real exchange rate volatility across nominal regimes. A statistically signifcant HBS effect for sterling-dollar captures its longrun trend and explains a proportion of variation in changes in the real rate that is proportional to the time horizon of the change. There is signifcant evidence of nonlinear reversion towards long-run equilibrium and downwards shifts in volatility during &xed nominal exchange rate regimes.purchasing power parity ; real exchange rate ; nonlinear dynamics ; Harrod-Balassa-Samuelson effect ; productivity differentials

Market entry costs, producer heterogeneity and export dynamics

As the exchange rate, foreign demand, production costs and export promotion policies evolve, manufacturing firms are continually faced with two issues: whether to be an exporter, and if so, how much to export. we develop a dynamic structural model of export supply that characterizes these two decisions and estimate the model using plant-level panel data on Colombian chemical producers. The model embodies uncertainty, plant-level heterogeneity in export profits, and sunk entry costs for plants breaking into foreign markets. Our estimates, and the simulation exercises that they support, yield several implications. First, entry costs are typically large, but vary greatly across proucers. second, there is substantial cross-plant heterogeneity in gross expected export profit streams. Third, these large entry costs make expectations about future exporting conditions important for many producers, so changes in the exchange rate regime that are credible induce much more entry than those that are not. Fourth, however, most of the entry and exit takes place among marginal exporters who contribute little to aggregate export revenues. Finally, subsidies on export earnings have much large impact on export revenues(per dollar spent)than subsidies that reduce the entry costs faced by new exporters.