Microfluidic detection and analysis by integration of evanescent wave sensing with thermocapillary actuation

An integrated system capable of microfluidic actuation, detection and sensing is described which combines evanescent wave sensing with thermocapillary manipulation. Liquid droplets or streams transported across the beam path of a planar thin film waveguide, which encapsulates the microheater array, induce attenuation of the propagating waveguide modes. The attenuated signal is used to monitor droplet location, dye concentration in aqueous solutions and reaction kinetics for enzymatic hydrolysis of the sugar X-galactose by beta-galactosidase

Microfluidic detection and analysis by integration of thermocapillary actuation with a thin-film optical waveguide

We demonstrate a nonintrusive optical method for microfluidic detection and analysis based on evanescent wave sensing. The device consists of a planar thin-film waveguide integrated with a microfluidic chip for directed surface flow. Microliter droplets are electronically transported and positioned over the waveguide surface by thermocapillary actuation. The attenuated intensity of propagating modes is used to detect droplet location, to monitor dye concentration in aqueous solutions, and to measure reaction rates with increasing surface temperature for a chromogenic biochemical assay. This study illustrates a few of the capabilities possible by direct integration of optical sensing with surface-directed fluidic devices

Polarization Enhancement in Short Period Superlattices via Interfacial Intermixing

The effect of intermixing at the interface of short period PbTiO$_3$/SrTiO$_3$ superlattices is studied using first-principles density functional theory. The results indicate that interfacial intermixing significantly enhances the polarization within the superlattice. This enhancement is directly related to the off-centering of Pb and Sr cations and can be explained through a discussion of interacting dipoles. This picture should be general for a wide range of multicomponent superlattices and may have important consequences for the design of ferroelectric devices.Comment: 4 pages, 6 figure

Testing Models of Distributive Politics using Exit Polls to Measure Voters Preferences and Partisanship

This paper tests various hypotheses about distributive politics by studying the distribution of federal spending across U.S. states over the period 1978-2002. We improve on previous work by using survey data to measure the share of voters in each state that are Democrats, Republicans, and independents, or liberals, conservatives and moderates. We find no evidence that the allocation of federal spending to the states is distorted by strategic manipulation to win electoral support. States with many swing voters are not advantaged compared to states with more loyal voters, nor do “battleground states” attract more federal funds. Moreover, we find that spending has little or no effect on voters’ choices, whereas partisanship and ideology have massive effects.Ideological attitudes, partisanship, distributive politics, federal budget

Two-photon imaging of cell-specific fluorophores in transgenic mice – an exploratory tool to study mechanisms of white matter injury

Relatively little is known about specific pathways leading to structural and functional disruption of axons and glial cells in white matter. Because focal cerebral ischemia in humans damages both gray and white matter, an understanding of white matter injury is important in devising potential therapeutic approaches. We have developed a novel brain slice model from transgenic mice under control of cell-specific promoters to understand interactions between oligodendrocytes and axons under high resolution twophoton microscopy. Our data extends over previous findings the vulnerability of oligodendrocytes and axons both in culture and in slice preparations to glutamate toxicity during stroke and hypoglycemia. Conditions as different as stroke, trauma, perinatal brain injury, and multiple sclerosis may share common mechanisms of white matter injury.N/

TESTING MODELS OF DISTRIBUTIVE POLITICSUSING EXIT POLLS TO MEASURE VOTERPREFERENCES AND PARTISANSHIP

This paper tests various hypotheses about distributive politics by studying the distributionof federal spending across U.S. states over the period 1978-2002. We improve onprevious work by using survey data to measure the share of voters in each state that areDemocrats, Republicans, and independents, or liberals, conservatives and moderates. Wefind no evidence for the "swing voter" hypothesis { that is, no significant associationbetween the amount of federal funds a state receives and the fraction of independents ormoderates in the state. We also find no evidence for the "battleground state" hypothesis -no significant association between the amount of federal funds and the degree of partisanbalance in a state. Modest support is found for the \partisan supporters" hypothesis, whichconjectures that politicians will favour areas that contain a large percentage of their coresupporters.Electoral competition, swing voter, partisanship, election closeness, USFederal Spending.

Partisan Bias in Economic News: Evidence on the Agenda-Setting Behavior of U.S. Newspapers

We study the agenda-setting political behavior of a large sample of U.S. newspapers during the last decade, and the behavior of smaller samples for longer time periods. Our purpose is to examine the intensity of coverage of economic issues as a function of the underlying economic conditions and the political affiliation of the incumbent president, focusing on unemployment, inflation, the federal budget and the trade deficit. We investigate whether there is any significant correlation between the endorsement policy of newspapers, and the differential coverage of bad/good economic news as a function of the president's political affiliation. We find evidence that newspapers with pro-Democratic endorsement pattern systematically give more coverage to high unemployment when the incumbent president is a Republican than when the president is Democratic, compared to newspapers with pro-Republican endorsement pattern. This result is not driven by the partisanship of readers. There is on the contrary no evidence of a partisan bias -- or at least of a bias that is correlated with the endorsement policy -- for stories on inflation, budget deficit or trade deficit.

Partisan Bias in Economic News: Evidence on the Agenda-Setting Behavior of U.S. Newspapers

We study the agenda-setting political behavior of a large sample of U.S. newspapers during the last decade, and the behavior of smaller samples for longer time periods. Our purpose is to examine the intensity of coverage of economic issues as a function of the underlying economic conditions and the political affiliation of the incumbent president, focusing on unemployment, inflation, the federal budget and the trade deficit. We investigate whether there is any significant correlation between the endorsement policy of newspapers, and the differential coverage of bad/good economic news as a function of the president's political affiliation. We find evidence that newspapers with pro- Democratic endorsement pattern systematically give more coverage to high unemployment when the incumbent president is a Republican than when the president is Democratic, compared to newspapers with pro-Republican endorsement pattern. This result is not driven by the partisanship of readers. There is on the contrary no evidence of a partisan bias - or at least of a bias that is correlated with the endorsement policy - for stories on inflation, budget deficit or trade deficit.