724 research outputs found

    Explicit bounds for the Riemann zeta-function on the 1-line

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    Explicit estimates for the Riemann zeta-function on the 11-line are derived using various methods, in particular van der Corput lemmas of high order and a theorem of Borel and Carath\'{e}odory.Comment: 32 page

    CAPIR: Collaborative Action Planning with Intention Recognition

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    We apply decision theoretic techniques to construct non-player characters that are able to assist a human player in collaborative games. The method is based on solving Markov decision processes, which can be difficult when the game state is described by many variables. To scale to more complex games, the method allows decomposition of a game task into subtasks, each of which can be modelled by a Markov decision process. Intention recognition is used to infer the subtask that the human is currently performing, allowing the helper to assist the human in performing the correct task. Experiments show that the method can be effective, giving near-human level performance in helping a human in a collaborative game.Comment: 6 pages, accepted for presentation at AIIDE'1

    Evaluation of the Effectiveness of a Positive Youth Development Program for Secondary Students in Macau

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    A well-tested comprehensive Chinese positive youth development program (Project P.A.T.H.S.) developed in Hong Kong has been modified and adapted for use in Macau. This program aims to help adolescent school children develop positively and to be better prepared for their future. The present study investigated the effectiveness of the Tier 1 Program of “P.A.T.H.S.” for Secondary 2 students of two pilot schools. Since there were “repeating” and “transferring” students joining the program, the effectiveness of the program on these particular groups of participants was also examined. The subjective outcome evaluations including participants' perceptions of the program, program instructors, benefits from the program, and overall satisfaction were positive. Although the longitudinal data from the objective outcome evaluation did not show any notable improvement, the overall effect of the program was found to be positive to the new comers in the junior secondary years. The existing evaluation findings suggest that the Secondary 2 program is especially effective to those newly joining the program. In view of the paucity of youth studies in Macau, the present study can contribute to evidence-based youth work and provide baseline data for the program to be evaluated in the Secondary 3 periods in the future

    Calpain mediates epithelial cell microvillar effacement by enterohemorrhagic Escherichia coli

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    A member of the attaching and effacing (AE) family of pathogens, enterohemorrhagic Escherichia coli (EHEC) induces dramatic changes to the intestinal cell cytoskeleton, including effacement of microvilli. Effacement by the related pathogen enteropathogenic E. coli (EPEC) requires the activity of the Ca(+2)-dependent host protease, calpain, which participates in a variety of cellular processes, including cell adhesion and motility. We found that EHEC infection results in an increase in epithelial (CaCo-2a) cell calpain activity and that EHEC-induced microvillar effacement was blocked by ectopic expression of calpastatin, an endogenous calpain inhibitor, or by pretreatment of intestinal cells with a cell-penetrating version of calpastatin. In addition, ezrin, a known calpain substrate that links the plasma membrane to axial actin filaments in microvilli, was cleaved in a calpain-dependent manner during EHEC infection and lost from its normal locale within microvilli. Calpain may be a central conduit through which EHEC and other AE pathogens induce enterocyte cytoskeletal remodeling and exert their pathogenic effects

    Dispersion pattern and sampling plan for Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in a citrus orchard

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    The ecology of the psyllid and its spatial distribution as the basis for the development of a reliable sampling plan are very important. The abundance and spatial distribution of Diaphorina citri (Hemiptera: Psyllidae) were studied in a commercial citrus orchard in southwestern Sarawak, Malaysia from April 2013 to December 2014. The spatial distribution of D. citri eggs, nymphs and adults were analysed using Taylor’s power law and Iwao’s patchiness regression. Taylor’s power law fitted the data better and produced higher values of R2 than Iwao’s regression model but did not work well with the egg populations. Based on both regression models, the field dispersion patterns of D. citri eggs, nymphs and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly >1. By homogeneity tests on both regression methods, the slopes of Taylor’s power law and Iwao’s regression model did not differ significantly for the D. citri population on honey tangerine for both years. The minimum number of flush shoots per tree required for estimates of D. citri densities varied from 2, 4 and 6 flush shoots for adults, nymphs and eggs, respectively, for the average density of each developmental stage obtained during our studies. Prediction suggested that a sampling plan consisting of 10 trees with the optimum number of six flush shoots per tree was required for reasonably accurate density estimation of the three life stages of D. citri acceptable enough for population studies and pest management program in citrus orchards

    Impacts of Horticultural Mineral Oils and Two Insecticide Practices on Population Fluctuation of Diaphorina citri and Spread of Huanglongbing in a Citrus Orchard in Sarawak

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    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33′N, 110° 41′E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC24HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined
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