FIXOR: A New Approach to Neutralizing Landmines and UXO

Canada’s MREL Specialty Explosive Products Limited introduces a new approach to neutralizing landmines and UXO

Benthic biomass size spectra in shelf and deep-sea sediments

The biomass distributions of marine benthic metazoans (meio- to macro-fauna, 1 ?g–32 mg wet weight) across three contrasting sites were investigated to test the hypothesis that allometry can consistently explain observed trends in biomass spectra. Biomass (and abundance) size spectra were determined from observations made at the Faroe–Shetland Channel (FSC) in the Northeast Atlantic (water depth 1600 m), the Fladen Ground (FG) in the North Sea (150 m), and the hypoxic Oman Margin (OM) in the Arabian Sea (500 m). Observed biomass increased with body size as a power law at FG (scaling exponent, b = 0.16) and FSC (b = 0.32), but less convincingly at OM (b = 0.12 but not significantly different from 0). A simple model was constructed to represent the same 16 metazoan size classes used for the observed spectra, all reliant on a common detrital food pool, and allowing the three key processes of ingestion, respiration and mortality to scale with body size. A micro-genetic algorithm was used to fit the model to observations at the sites. The model accurately reproduces the observed scaling without needing to include the effects of local influences such as hypoxia. Our results suggest that the size-scaling of mortality and ingestion are dominant factors determining the distribution of biomass across the meio- to macrofaunal size range in contrasting marine sediment communities. Both the observations and the model results are broadly in agreement with the "metabolic theory of ecology" in predicting a quarter power scaling of biomass across geometric body size classes

Loading a vapor cell magneto-optic trap using light-induced atom desorption

Low intensity white light was used to increase the loading rate of $^{87}$Rb atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb partial pressure reached a new equilibrium value in less than 10 seconds after switching on the broadband light source. After the source was turned off, the partial pressure returned to its previous value in $1/e$ times as short as 10 seconds.Comment: 7 pages, 6 figure

Generalized dynamic reduction in finite element dynamic optimization

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76662/1/AIAA-8826-211.pd

How ethnic and linguistic heterogeneity influence the prospects for civil society: A comparative study of citizenship behavior

While the positive consequences of social capital and civil society are widely accepted and appreciated, the question of how they originate and can be sustained has received relatively little attention from scholars. In this study, we approach this question from a cross-national and individual-level perspective by examining how population heterogeneity in the form of ethnic and linguistic diversity affects citizenship behavior, measured by cognitive and interpersonal engagement about politics, membership in voluntary associations, and interpersonal trust. Based on data collected in 44 countries, our analyses show that heterogeneity does affect the quality of civil society in a country. However, indicators of population heterogeneity do not have uniformly positive or negative effects on individual-level measures of civil society - while they reduce some, they shore up others. © 2006 Southern Political Science Association

Legitimacy from above: The partisan foundations of support for the political system in democracies

We investigate the partisan foundations of political legitimacy. We argue that the goals parties pursue shape their supporters' views about the political system via the messages they communicate about the desirability of the political system. Combining public opinion survey data collected in 15 democracies with data on the goal orientations and policy positions of 116 political parties, we find that office-seeking parties take more positive positions toward the status quo of the political regime than policy-seeking parties. Moreover, we find that these positions have consequences. Specifically, supporters of parties with more positive positions toward the system report systematically higher levels of support than supporters of parties that communicate more negative views. Taken together, these findings suggest that political parties play an active role in shaping citizens' views of the political system and that office-seeking parties in particular mobilize consent among citizens in contemporary democracies. © European Consortium for Political Research

Frequency down conversion through Bose condensation of light

We propose an experimental set up allowing to convert an input light of wavelengths about $1-2 \mu m$ into an output light of a lower frequency. The basic principle of operating relies on the nonlinear optical properties exhibited by a microcavity filled with glass. The light inside this material behaves like a 2D interacting Bose gas susceptible to thermalise and create a quasi-condensate. Extension of this setup to a photonic bandgap material (fiber grating) allows the light to behave like a 3D Bose gas leading, after thermalisation, to the formation of a Bose condensate. Theoretical estimations show that a conversion of $1 \mu m$ into $1.5 \mu m$ is achieved with an input pulse of about $1 ns$ with a peak power of $10^3 W$, using a fiber grating containing an integrated cavity of size about $500 \mu m \times 100 \mu m^2$.Comment: 4 pages, 1 figure