Computational Mechanism Design: A Call to Arms

Game theory has developed powerful tools for analyzing decision making in systems with multiple autonomous actors. These tools, when tailored to computational settings, provide a foundation for building multiagent software systems. This tailoring gives rise to the field of computational mechanism design, which applies economic principles to computer systems design

C-erbB2 mRNA expression in human breast tumours: comparison with c-erbB2 DNA amplification and correlation with prognosis.

In this study, we have investigated the expression of the proto-oncogene c-erbB2 in a total of 70 human primary breast tumours. In agreement with other workers, we observed c-erbB2 gene amplification in 17.5% of the tumours studied. In addition, we carried out a comprehensive analysis of c-erbB2 mRNA expression in the tumours using RNase mapping and in situ hybridisation techniques. Our results indicated a more frequent (30%) overexpression of c-erbB2 mRNA, which was associated only with breast carcinomas of a ductal origin. Furthermore, analysis of the c-erbB2 mRNA gene locus in the same tumours demonstrated that enhanced c-erbB2 expression could occur in the presence or absence of gene amplification, suggesting that additional molecular mechanisms may result in overexpression of c-erbB2 mRNA in human mammary tumours. In situ hybridisation showed that elevated levels of c-erbB2 mRNA were specific to malignant cells within the breast tumour. Analysis of the association between c-erbB2 mRNA overexpression and clinicopathological factors revealed a significant correlation with poor tumour grade, but not with steroid receptor status or patient menopausal status. No significant correlation was observed between overexpression of c-erbB2 mRNA and early disease recurrence in our group of patients, although there was a definite trend towards poorer prognosis

Computational-Mechanism Design: A Call to Arms

Game theory has developed several powerful tools for analyzing decision making in systems composed of multiple autonomous actors. Given this fact, AI practitioners would like to exploit these tools when building software systems containing multiple agents. However, to do this, the tools must be tailored to computational settings. To this end, the authors provide an overview of computational-mechanism design, which deals with the application of economic principles in computer systems design. Moreover, because many complex systems are inherently distributed, they also present initial results from the relatively new field of distributed-computational-mechanism design and outline the key challenges involved in making the ideas practicable.Engineering and Applied Science

A selected ion flow tube study of the ion-molecule reactions of monochloroethene, trichloroethene and tetrachloroethene

Data for the rate coefficients and product cations of the reactions of a large number of atomic and small molecular cations with monochloroethene, trichloroethene and tetrachloroethene in a selected ion flow tube at 298 K are reported. The recombination energy of the ions range from 6.27 eV (H$_3$O$^+$) through to 21.56 eV (Ne$^+$). Collisional rate coefficients are calculated by modified average dipole orientation theory and compared with experimental values. Thermochemistry and mass balance predict the most feasible neutral products. Together with previously reported results for the three isomers of dichloroethene (J. Phys. Chem. A., 2006, 110, 5760), the fragment ion branching ratios have been compared with those from threshold photoelectron photoion coincidence spectroscopy over the photon energy range 9-22 eV to determine the importance or otherwise of long-range charge transfer. For ions with recombination energy in excess of the ionisation energy of the chloroethene, charge transfer is energetically allowed. The similarity of the branching ratios from the two experiments suggest that long-range charge transfer is dominant. For ions with recombination energy less than the ionisation energy, charge transfer is not allowed; chemical reaction can only occur following formation of an ion-molecule complex, where steric effects are more significant. The products that are now formed and their percentage yield is a complex interplay between the number and position of the chlorine atoms with respect to the C=C bond, where inductive and conjugation effects can be important

Payment Rules through Discriminant-Based Classifiers

In mechanism design it is typical to impose incentive compatibility and then derive an optimal mechanism subject to this constraint. By replacing the incentive compatibility requirement with the goal of minimizing expected ex post regret, we are able to adapt statistical machine learning techniques to the design of payment rules. This computational approach to mechanism design is applicable to domains with multi-dimensional types and situations where computational efficiency is a concern. Specifically, given an outcome rule and access to a type distribution, we train a support vector machine with a special discriminant function structure such that it implicitly establishes a payment rule with desirable incentive properties. We discuss applications to a multi-minded combinatorial auction with a greedy winner-determination algorithm and to an assignment problem with egalitarian outcome rule. Experimental results demonstrate both that the construction produces payment rules with low ex post regret, and that penalizing classification errors is effective in preventing failures of ex post individual rationality

DNA ploidy and proliferative activity (S-phase) in childhood soft-tissue sarcomas: their value as prognostic indicators.

The value of DNA ploidy as a prognostic indicator is well established in many cancers, but recent studies in childhood rhabdomyosarcoma (RMS) have been contradictory. In a retrospective study of 128 cases of soft-tissue sarcoma (STS) diagnosed since 1980, the prognostic value of clinical, histological and flow cytometric parameters was compared, using univariate and multivariate methods. Eighty-one RMSs, 18 extraosseous Ewing's (EOE)/peripheral neuroectodermal tumours (PNETs) and 29 other non-RMS STSs were histologically and clinically reviewed. Five year actuarial survival was 63.4% for all STSs and 69.4% for RMSs. Paraffin-embedded tissue blocks were available for flow cytometry in 90 cases. Of the RMSs, 65.5% were aneuploid [DNA index (DI) > 1.1] compared with 23% of the EOE/PNETs and 31% of non-RMS STSs. Median S-phase was also significantly higher in RMSs (17.0%) than in other STSs (10.8%) (P = 0.0023). Univariate analysis in RMSs showed that stage, ploidy status, S-phase, site and tumour size all had a significant impact on survival. In multivariate analysis of 59 cases of RMS, one clinical and two flow cytometric parameters were independently associated with poor prognosis. These were stage (IV), nonhyperdiploidy (DI < 1.10 and > 1.8) and a high rate of proliferative activity (S-phase > 14.0%). These results confirm that ploidy and S-phase are important new prognostic indicators in rhabdomyosarcoma

Investigation of shock waves in explosive blasts using fibre optic pressure sensors

The published version of this article may be accessed at the link below. Copyright @ IOP Publishing, 2006.We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1 mm(2) in overall cross-section with rise times in the mu s regime and pressure ranges typically 900 kPa (9 bar). Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Results from blast tests are presented in which up to six sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front.Support from the UK Engineering&Physical Sciences Research Council and Dstl Fort Halstead through the MoD Joint Grants Scheme are acknowledged. WN MacPherson is supported by an EPSRC Advanced Research Fellowship

Cognitive behaviour therapy (CBT) for anxiety and depression in adults with mild intellectual disabilities (ID): a pilot randomised controlled trial

Background: Several studies have showed that people with intellectual disabilities (ID) have suitable skills to undergo cognitive behavioural therapy (CBT). Case studies have reported successful use of cognitive behavioural therapy techniques (with adaptations) in people with ID. Modified cognitive behavioural therapy may be a feasible and effective approach for the treatment of depression, anxiety, and other mood disorders in ID. To date, two studies have reported group-based manaulised cognitive behavioural treatment programs for depression in people with mild ID. However, there is no individual manualised programme for anxiety or depression in people with intellectual disabilities. The aims of the study are to determine the feasibility of conducting a randomised controlled trial for CBT in people with ID. The data will inform the power calculation and other aspects of carrying out a definitive randomised controlled trial.Methods: Thirty participants with mild ID will be allocated randomly to either CBT or treatment as usual (TAU). The CBT group will receive up to 20 hourly individual CBT over a period of 4 months. TAU is the standard treatment which is available to any adult with an intellectual disability who is referred to the intellectual disability service (including care management, community support, medical, nursing or social support). Beck Youth Inventories (Beck Anxiety Inventory & Beck Depression Inventory) will be administered at baseline; end of treatment (4 months) and at six months to evaluate the changes in depression and anxiety. Client satisfaction, quality of life and the health economics will be secondary outcomes.Discussion: The broad outcome of the study will be to produce clear guidance for therapists to apply an established psychological intervention and identify how and whether it works with people with intellectual disabilities

Minimizing energy below the glass thresholds

Focusing on the optimization version of the random K-satisfiability problem, the MAX-K-SAT problem, we study the performance of the finite energy version of the Survey Propagation (SP) algorithm. We show that a simple (linear time) backtrack decimation strategy is sufficient to reach configurations well below the lower bound for the dynamic threshold energy and very close to the analytic prediction for the optimal ground states. A comparative numerical study on one of the most efficient local search procedures is also given.Comment: 12 pages, submitted to Phys. Rev. E, accepted for publicatio

Young people, inequality and violence during the COVID-19 lockdown in Uganda

This working paper reports findings from a qualitative study on how response measures during the early stages of the COVID-19 pandemic in Uganda have affected the lives of adolescent young people. The study was conducted as part of a broader research project: Contexts of Violence in Adolescence Cohort Study (CoVAC), with data collected through mobile phone interviews in May-June 2020 with 18 girls and 16 boys (mainly aged 16-19 years) who have been participants in our longitudinal study. The data are contextualized within longitudinal biographical narratives of these young people that have been developed since 2018 and which helped us to illuminate the significance of the crisis in their everyday lives. The analysis shows how effects on young people of the lockdown varied according to gender, location, mobility and socio-economic background, amplifying inequalities and creating the conditions for multiple forms of violence