Proposal for demonstrating the Hong-Ou-Mandel effect with matter waves

The Hong-Ou-Mandel (HOM) effect is a striking demonstration of destructive quantum interference between pairs of indistinguishable bosons, realised so far only with massless photons. Here we propose an experiment which can realise this effect in the matter-wave regime using pair-correlated atoms produced via a collision of two Bose-Einstein condensates and subjected to two laser induced Bragg pulses. We formulate a novel measurement protocol appropriate for the multimode matter-wave field, which---unlike the typical two-mode optical case---bypasses the need for repeated measurements under different displacement settings of the beam-splitter, thus dramatically reducing the number of experimental runs required to map out the interference visibility. The protocol can be utilised in related matter-wave schemes; here we focus on condensate collisions and by simulating the entire experiment we predict a HOM-dip visibility of ~69%. By being larger than 50%, such a visibility highlights strong quantum correlations between the atoms and paves the way for a possible demonstration of a Bell inequality violation with massive particles in a related Rarity-Tapster setup.Comment: Essentially the same version as v2, except in Nature Communications style; for Supplementary Information see the source fil

Swift, Certain, and Fair: A Pilot Program of the Probation Department in Monroe County, New York

For my capstone, I will be breaking down some components of the evaluation of the Swift, Certain, and Fair probation program in Monroe County, New York. Monroe County Probation’s Swift, Certain & Fair Model Pilot Program focuses on offenders between 16–24 years old who have been arrested on certain gun charges (more specifically, Criminal Possession of a Weapon in the second degree). It is designed to help change the behaviors of those who may otherwise be unlikely to succeed under traditional probation supervision. This model extends the program development and analysis of a program known as HOPE (Hawaii Opportunity Probation with Enforcement). Swift, certain and fair responses to probationers’ non-compliant behavior and violations are the essential components of this model, and Rochester program developers modified this basic model suit the purpose of managing high-risk gun-related offenders. The outcome evaluation of Swift, Certain & Fair focuses on how well the program is running and whether the program has been successful in its goal to reduce recidivism and gun violence in Rochester, New York. This capstone will focus more specifically on the theory behind the program, the methodology used for this evaluation along with how the data is collected, and the preliminary results of this evaluation

Fish powder as a low-cost component in media for producing bacterial cellulose

Some bacteria can produce extracellular bacterial cellulose (BC). This polysaccharide is chemically identical to cellulose produced by plants but has no associated lignin and hemicelluloses. The unique mechanical properties, chemical stability and purity allow BC to be exploited for a range of biomedical applications. However, medium costs limit commercial BC production. The suitability of using fish powder as a low-cost media component for producing BC by submerged culture of Gluconacetobacter xylinus in shake flasks was investigated. Fish powder was made by drying and grinding Koi carp (Cyprinus carpio), a pest fish in New Zealand waterways. Fermentations were done at 30oC in a growth medium containing 50 g/L glucose, the required minerals, and either 5 g/L yeast extract or 15 g/L fish powder, The BC yield on both yeast extract and fish powder was 0.04 g/g glucose, demonstrating fish powder was a suitable low cost ingredient for supplying nitrogen and amino acids in the media

‘Eating at us’: Representations of knowledge in the activist documentary film Food, Inc.

© 2011, © 2011 Taylor and Francis Group, LLC. Writing on social movement learning and environmental adult education invokes particular views on knowledge that need further examination and development in relation to food social movements. Although food social movements take different forms, the paper argues that the politics of food knowledge is at the centre of many of these movements. Contributing to the discourse of social movement learning, this article focuses on the film Food, Inc., an important activist resource and documentary film about a particular food movement. We analyse how it legitimates certain forms of knowledge about food production and consumption and de-legitimates others. Whilst a useful case study on knowledge and film activism in itself, the article seeks to challenge what it sees as some key tenets about knowledge in social movement learning literature. One key tenet is that it is self-evident whose interests are served by ‘ordinary people's knowledge’ and ‘scientific knowledge.’ Instead, it is argued that when it comes to collective action for food there is ambiguity, messiness and contestation about what constitutes knowledge and, in particular, anti-capitalist knowledge. But realisation of such ambiguity, messiness and contestation should not lead to paralysed inaction, but to informed and nuanced action. A question then for social movement learning practitioners is how they can mobilise social change through a broader sense of knowledge and its effects

New approaches for estimating risk from exposure to diethylstilbestrol.

A subgroup from a National Institute of Environmental Health Sciences, workshop concerned with characterizing the effects of endocrine disruptors on human health at environmental exposure levels considered the question, If diethylstilbestrol (DES) were introduced into the market for human use today and likely to result in low-dose exposure of the human fetus, what would be required to assess risk? On the basis of an analysis of the quality of data on human DES exposure, the critical times and doses for inducing genital tract malformations and cancer must be determined. This would be facilitated through analysis of the ontogeny of estrogen receptor expression in the developing human genital tract. Models of low-dose estrogenic effects will have to be developed for human and rodent genital tract development. Mouse models offer many advantages over other potential animal models because of the wealth of the earlier literature, the availability of sensitive end points, the availability of mutant lines, and the possibility of generating genetically engineered model systems. Through multidisciplinary approaches, it should be possible to elucidate the cellular and molecular mechanisms of endocrine disruption elicited by estrogens during development and facilitate an assessment of risk to humans

Food Pedagogies: Histories, Definitions and Moralities

Chapter on

Stably free modules over virtually free groups

Let $F_m$ be the free group on $m$ generators and let $G$ be a finite nilpotent group of non square-free order; we show that for each $m\ge 2$ the integral group ring ${\bf Z}[G\times F_m]$ has infinitely many stably free modules of rank 1.Comment: 9 pages. The final publication is available at http://www.springerlink.com doi:10.1007/s00013-012-0432-

SIMS chemical analysis of extended impacts on the leading and trailing edges of LDEF experiment AO187-2

Numerous 'extended impacts' found in both leading and trailing edge capture cells were successfully analyzed for the chemical composition of projectile residues by secondary ion mass spectrometry (SIMS). Most data were obtained from the trailing edge cells where 45 of 58 impacts were classified as 'probably natural' and the remainder as 'possibly man-made debris.' This is in striking contrast to leading edge cells where 9 of 11 impacts so far measured are definitely classified as orbital debris. Although all the leading edge cells had lost their plastic entrance foils during flight, the rate of foil failure was similar to that of the trailing edge cells, 10 percent of which were recovered intact. Ultraviolet embrittlement is suspected as the major cause of failure on both leading and trailing edges. The major impediment to the accurate determination of projectile chemistry is the fractionation of volatile and refractory elements in the hypervelocity impact and redeposition processes. This effect had been noted in a simulation experiment but is more pronounced in the LDEF capture cells, probably due to the higher average velocities of the space impacts. Surface contamination of the pure Ge surfaces with a substance rich in Si, but also containing Mg and Al, provides an additional problem for the accurate determination of impactor chemistry. The effect is variable, being much larger on surfaces that were exposed to space than in those cells that remained intact. Future work will concentrate on the analyses of more leading edge impacts and the development of new SIMS techniques for the measurement of elemental abundances in extended impacts