Four-Weight Spin Models and Jones Pairs

We introduce and discuss Jones pairs. These provide a generalization and a new approach to the four-weight spin models of Bannai and Bannai. We show that each four-weight spin model determines a ``dual'' pair of association schemes

The Role of Auctions in Allocating Public Resources

This paper provides an economic framework within which to consider the effectiveness and limitations of auction markets. The paper looks at the use of auctions as a policy instrument and the effects of auction design on consumer interests, the efficient allocation of resources, and industry competitiveness.Australia; Research; Ascending-bid auction; Auctions; Bidders; Conservation funds; Descending-bid auction; Dutch auction; English auction; Environmental Management; First-price sealed-bid auction; Infrastructure; Markets; Oral auction; Outcry auction; Pollutant emission permits; Power supply contracts; Public resources; Radio- spectrum; Second-price sealed-bid auction Spectrum licences; Vickrey auction; Water rights;

The making of a new working class? A study of collective actions of migrant workers in South China

In this study, we argue that the specific process of the proletarianization of Chinese migrant workers contributes to the recent rise of labour protests. Most of the collective actions involve workers' conflict with management at the point of production, while simultaneously entailing labour organizing in dormitories and communities. The type of living space, including workers' dormitories and migrant communities, facilitates collective actions organized not only on bases of locality, ethnicity, gender and peer alliance in a single workplace, but also on attempts to nurture workers' solidarity in a broader sense of a labour oppositional force moving beyond exclusive networks and ties, sometimes even involving cross-factory strike tactics. These collective actions are mostly interest-based, accompanied by a strong anti-foreign capital sentiment and a discourse of workers' rights. By providing detailed cases of workers' strikes in 2004 and 2007, we suggest that the making of a new working class is increasingly conscious of and participating in interest-based or class-oriented labour protests

Culture of Papaya Explant in Solid - Liquid Media Sequence as a Rapid Method for Producing Multiple Shoots

Culturing papaya axillary buds obtained from mature field-grown trees on solid MS + 0.1 mg/l BA + 500 mg/ l casein hydrolysate + 0.38 mg/l riboflavin produced less than 2 shoots per explant over a period of2 to 18 weeks. However, 82 times more shoots were produced when the explants were cultured on solid medium for 10 weeks followed by another 10 weeks in liquid medium

Directional optical switching and transistor functionality using optical parametric oscillation in a spinor polariton fluid

Over the past decade, spontaneously emerging patterns in the density of polaritons in semiconductor microcavities were found to be a promising candidate for all-optical switching. But recent approaches were mostly restricted to scalar fields, did not benefit from the polariton's unique spin-dependent properties, and utilized switching based on hexagon far-field patterns with 60{\deg} beam switching (i.e. in the far field the beam propagation direction is switched by 60{\deg}). Since hexagon far-field patterns are challenging, we present here an approach for a linearly polarized spinor field, that allows for a transistor-like (e.g., crucial for cascadability) orthogonal beam switching, i.e. in the far field the beam is switched by 90{\deg}. We show that switching specifications such as amplification and speed can be adjusted using only optical means

Analysis of the Tuning Sensitivity of Silicon-on-Insulator Optical Ring Resonators

High-quality-factor optical ring resonators have recently been fabricated in thin silicon-on-insulator (SOI). Practical applications of such devices will require careful tuning of the precise location of the resonance peaks. In particular, one often wants to maximize the resonance shift due to the presence of an active component and minimize the resonance shift due to temperature changes. This paper presents a semianalytic formalism that allows the prediction of such resonance shifts from the waveguide geometry. This paper also presents the results of experiments that show the tuning behavior of several ring resonators and find that the proposed semianalytic formalism agrees with the observed behavior

Overcoming data sparsity

Unilever is currently designing and testing recommendation algorithms that would make recommendations about products to online customers given the customer ID and the current content of their basket. Unilever collected a large amount of purchasing data that demonstrates that most of the items (around 80%) are purchased infrequently and account for 20% of the data while frequently purchased items account for 80% of the data. Therefore, the data is sparse, skewed and demonstrates a long tail. Attempts to incorporate the data from the long tail, so far have proved difficult and current Unilever recommendation systems do not incorporate the information about infrequently purchased items. At the same time, these items are more indicative of customers' preferences and Unilever would like to make recommendations from/about these items, i.e. give a rank ordering of available products in real time. Study Group suggested to use the approach of bipartite networks to construct a similarity matrix that would allow the recommendation scores for different products to be computed. Given a current basket and a customer ID, this approach gives recommendation scores for each available item and recommends the item with the highest score that is not already in the basket. The similarity matrix can be computed offline, while recommendation score calculations can be performed live. This report contains the summary of Study Group findings together with the insights into properties of the similarity matrix and other related issues, such as recommendation for the data collection