title: Utilizing popularity characteristics for product recommendation

authors: Ahn, Hyung Jun

subjects: automated product recommendation

abstract: This paper presents a novel approach to automated product recommendation based on the popularity characteristics of products. Popularity plays a significant role in the consumer purchasing process but has not been given much attention in recommendation research. A three-dimensional model of popularity is used to develop popularity classes of products. These are joined with the MovieLens dataset to create a hybrid movie recommendation system that combines genre and popularity information. As compared with collaborative filtering, the hybrid system shows positive results under the conditions of data sparsity and cold-starting. Many interesting issues for further research are suggested.

text: Utilizing popularity characteristics for product recommendation This paper presents a novel approach to automated product recommendation based on the popularity characteristics of products. Popularity plays a significant role in the consumer purchasing process but has not been given much attention in recommendation research. A three-dimensional model of popularity is used to develop popularity classes of products. These are joined with the MovieLens dataset to create a hybrid movie recommendation system that combines genre and popularity information. As compared with collaborative filtering, the hybrid system shows positive results under the conditions of data sparsity and cold-starting. Many interesting issues for further research are suggested.

year: 2006

title: Purification and characterization of Ak.1 protease, a thermostable subtilisin with a disulphide bond in the substrate-binding cleft

authors: Toogood, Helen S.

subjects: calcium binding

abstract: Ak.1 protease, a thermostable subtilisin isolated originally from Bacillus st. Ak.1, was purified to homogeneity from the Escherichia coli clone PB5517. It is active against substrates containing neutral or hydrophobic branched-chain amino acids at the P₁ site, such as valine, alanine or phenylalanine. The Km and kcat of the enzyme decrease with decreasing temperature, though not to the same degree with all substrates, suggesting that specificity changes with temperature. The protease is markedly stabilized by Ca²⁺ ions. At 70 °C, a 10-fold increase in Ca²⁺ concentration increases the half-life by three orders of magnitude. Ak.1 protease is stabilized by Ca²⁺ to a greater extent than is thermitase. This may be due, in part, to the presence of an extra Ca²⁺-binding site in Ak.1 protease. Other metal ions, such as Sr²⁺, increase the thermostability of the enzyme, but to a significantly lower degree than does Ca²⁺. The structure of the protease showed the presence of a disulphide bond located within the active-site cleft. This bond influences both enzyme activity and thermostability. The disulphide bond appears to have a dual role: maintaining the integrity of the substrate-binding cleft and increasing the thermostability of the protease. The protease was originally investigated to determine its usefulness in the clean-up of DNA at high temperatures. However, it was found that this protease has a limited substrate specificity, so this application was not explored further.

text: Purification and characterization of Ak.1 protease, a thermostable subtilisin with a disulphide bond in the substrate-binding cleft Ak.1 protease, a thermostable subtilisin isolated originally from Bacillus st. Ak.1, was purified to homogeneity from the Escherichia coli clone PB5517. It is active against substrates containing neutral or hydrophobic branched-chain amino acids at the P₁ site, such as valine, alanine or phenylalanine. The Km and kcat of the enzyme decrease with decreasing temperature, though not to the same degree with all substrates, suggesting that specificity changes with temperature. The protease is markedly stabilized by Ca²⁺ ions. At 70 °C, a 10-fold increase in Ca²⁺ concentration increases the half-life by three orders of magnitude. Ak.1 protease is stabilized by Ca²⁺ to a greater extent than is thermitase. This may be due, in part, to the presence of an extra Ca²⁺-binding site in Ak.1 protease. Other metal ions, such as Sr²⁺, increase the thermostability of the enzyme, but to a significantly lower degree than does Ca²⁺. The structure of the protease showed the presence of a disulphide bond located within the active-site cleft. This bond influences both enzyme activity and thermostability. The disulphide bond appears to have a dual role: maintaining the integrity of the substrate-binding cleft and increasing the thermostability of the protease. The protease was originally investigated to determine its usefulness in the clean-up of DNA at high temperatures. However, it was found that this protease has a limited substrate specificity, so this application was not explored further.

year: 2000

title: Improving prediction of potential for treatment completion at Tai Aroha

authors: Astridge Clarke,  Abigail Darcy

subjects: Treatment

abstract: Participant non-completion can be a major problem for treatment programmes. Staff may try to minimise non-completion by deciding who to select for treatment using professional intuition and referral information. It can be difficult for treatment staff to make these decisions regarding the potential for programme completion due to a lack of clear guidelines about what information to consider. This lack of clear guidelines can increase susceptibility to biases, and lead to unreliable and potentially inaccurate decisions. Research has identified ‘simple rules’ that are tools to aid decision-making quickly, effectively, and consistently. Therefore, using past treatment data, we1 aimed to identify predictors of programme completion vs. non-completion at Tai Aroha—a residential treatment programme based in Hamilton—to explore whether a “simple rule” can be developed from information readily available at the time of referral, to support staff decision-making when selecting offenders to attend treatment, with the potential to increase programme completion. We were successful in the development of a simple rule to aid Tai Aroha staff selection decisions. The implications, and limitations of our rule and our study are discussed, and future research relating to simple rules are identified.

text: Improving prediction of potential for treatment completion at Tai Aroha Participant non-completion can be a major problem for treatment programmes. Staff may try to minimise non-completion by deciding who to select for treatment using professional intuition and referral information. It can be difficult for treatment staff to make these decisions regarding the potential for programme completion due to a lack of clear guidelines about what information to consider. This lack of clear guidelines can increase susceptibility to biases, and lead to unreliable and potentially inaccurate decisions. Research has identified ‘simple rules’ that are tools to aid decision-making quickly, effectively, and consistently. Therefore, using past treatment data, we1 aimed to identify predictors of programme completion vs. non-completion at Tai Aroha—a residential treatment programme based in Hamilton—to explore whether a “simple rule” can be developed from information readily available at the time of referral, to support staff decision-making when selecting offenders to attend treatment, with the potential to increase programme completion. We were successful in the development of a simple rule to aid Tai Aroha staff selection decisions. The implications, and limitations of our rule and our study are discussed, and future research relating to simple rules are identified.

year: 2023