Saturation and alternate pathways in four-wave mixing in rubidium

We have examined the frequency spectrum of the blue light generated via four-wave mixing in a rubidium vapor cell inside a ring cavity. At high atomic density and input laser power, two distinct frequency components separated by $116 \pm 4$ MHz are observed, indicating alternate four-wave mixing channels through the $6p_{3/2}$ hyperfine states. The dependence of the generated light on excitation intensity and atomic density are explored, and indicate the primary process has saturated. This saturation results when the excitation rate through the 6p state becomes equal to the rate through the 5p state, giving no further gain with atomic density while a quadratic intensity dependence remains

An algebra of Stein operators

We build upon recent advances on the distributional aspect of Stein's method to propose a novel and flexible technique for computing Stein operators for random variables that can be written as products of independent random variables. We show that our results are valid for a wide class of distributions including normal, beta, variance-gamma, generalized gamma and many more. Our operators are $k$th degree differential operators with polynomial coefficients; they are straightforward to obtain even when the target density bears no explicit handle. As an application, we derive a new formula for the density of the product of $k$ independent symmetric variance-gamma distributed random variables.Comment: 20 page

The Law and Policy of Civil Rights: A Tactical Perspective for Educators

This article is presented to share with fellow professional teacher-scholars the preparation of a freshly-formulated teaching project. The aim of this project is to provide a classroom public policy study program wherein students debate policy issues in a carefully structured and professional fashion. This structure encompasses hands-on study of actually-litigated minority set-aside/affirmative action controversies before the U.S. Supreme Court, with every student always utilizing the primary documents (the litigants\u27 briefs) used by the Supreme Court Justices themselves. These briefs provide readymade resources fueling policy debate on either side of each case

Cooked turkey roasts have different processing characteristics then cooked beef roasts

Roasts were manufactured from lean beef and turkey by injecting with brine to 25% above green weight so the raw product contained 1.8% salt and 0.3% sodium phosphate. Meat muscle characteristics (pH and protein solubility) and processing characteristics were measured as cook yields and expressible moisture. The species significantly affects some basic properties of the meat. Turkey meat had significantly higher pH and extractible myofibrillar proteins than beef. The increased cook yield was correlated with higher pH and higher expressible moisture. The differences observed suggest that processors need to treat the starting materials differently

Two phase aqueous extraction of whey proteins in a polyethylene glycol - arabinogalactan system

The whey protein separation potential of aqueous two-phase systems of arabinogalactan [AG] (Lonza FiberAidTM) and polyethylene glycol [PEG], buffered with 10 mmol/g phosphate or citrate buffer, was studied. 100 mmol/g potassium chloride [KCl] was added as required. Previously-published phase equilibrium results were verified and the absorbance of whey protein isolate [WPI] in an AG-PEG solution was measured. The effect of pH, KCl concentration, initial WPI concentrations and upper to lower phase mass ratios on whey partitioning was studied. The best separation system contained 17.20% (w/w) AG, 7.20% (w/w) PEG, 10 mmol citrate buffer (pH 5.4) and 100 mmol KCl per gram of total system. The upper to lower phase mass and volume ratios were 1:1 and 16:11 respectively. Approximately 12 mg (mainly α-lactalbumin) of the 20 mg WPI added partitioned into the AG-rich upper phase. This system has potential to reduce chromatographic requirements in large scale separation of protein mixtures

Work placement reports: Student perceptions

Engineering students complete work placement reports after being on placement in industry, the aim is to increase work place learning and to increase students understanding about the placement, themselves, career direction and skills obtained. Third and fourth year engineering students perceptions on their report writing experience, academic feedback quality, and the effect of completing work placement reports on their learning and report writing ability, were surveyed. Third year students enjoyed the experience more than fourth year students and perceived greater benefits. Fourth year student opinion was mixed, reflecting greater experience and cynicism. Fourth year students rated feedback from academics higher than the third years, perhaps because their reports were more interesting for the academics. The fourth year students were more cynical on the benefits of reflecting and reviewing what they had learned, and many considered this was not important for being an engineer

The Industry and Recent Graduates: A Relationship in Transition

The industry is attempting to become more involved with graduates and currently-enrolled students in hospitality education programs. This article re- views the current situation, describes problems which exist, and proposes potential strategies to help resolve the problems

Analysis of rheological behaviour of titanium feedstocks formulated with a water-soluble binder system for powder injection moulding

Binder selection and formulation are critical in powder injection moulding. Binders play a key role in controlling the rheological properties of a feedstock and influence whether the resulting feedstock can be successfully injection moulded, debound and sintered without defects. A four-step process was used to mix hydride-dehydride titanium alloy (processed) powder (Ti-6Al-4 V) with a polyethylene glycol (PEG) based water soluble binder system. The rheological properties, including flow behaviour index, flow activation energy, fluidity and melt flow index of the homogeneous feedstock, were determined with a capillary rheometer. All feedstock formulations exhibited shear thinning flow behaviour. The optimum feedstock consisting of 60 vol.% powder content, 32 vol.% PEG, 6 vol.% polyvinyl butyryl and 2 vol.% stearic acid was suitable for titanium injection moulding

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