Solving the parity problem in one-dimensional cellular automata

The parity problem is a well-known benchmark task in various areas of computer science. Here we consider its version for one-dimensional, binary cellular automata, with periodic boundary conditions: if the initial configuration contains an odd number of 1s, the lattice should converge to all 1s; otherwise, it should converge to all 0s. Since the problem is ill-defined for even-sized lattices (which, by definition, would never be able to converge to 1), it suffices to account for odd-sized lattices only. We are interested in determining the minimal neighbourhood size that allows the problem to be solvable for any arbitrary initial configuration. On the one hand, we show that radius 2 is not sufficient, proving that there exists no radius 2 rule that can solve the parity problem, even in the simpler case of prime-sized lattices. On the other hand, we design a radius 4 rule that converges correctly for any initial configuration and formally prove its correctness. Whether or not there exists a radius 3 rule that solves the parity problem remains an open problem; however, we review recent data against a solution in radius 3, thus providing strong empirical evidence that there may not exist a radius 3 solution even for prime-sized lattices only, contrary to a recent conjecture in the literature.     

Family functioning processes and diabetic ketoacidosis in youths with type I diabetes.

Purpose/Objective: To examine relations between episodes of diabetic ketoacidosis (DKA) and parental warmth, parental negativity, and lack of responsibility for diabetes-related tasks in a sample of youths with Type 1 diabetes (T1D). Research Method/Design: 100 youths with T1D and their caregivers, recruited from an inpatient diabetes unit and an outpatient diabetes clinic, participated. Participants completed disease-specific measures of family functioning (e.g., parental warmth, parent and child perceptions of negativity, family responsibility for diabetes regimen), and medical information (e.g., glycosylated hemoglobin and incidences of DKA) was obtained from medical records. Results: Results showed that higher child perceptions of parental warmth and caring related to the regimen were associated with decreased odds of experiencing a DKA episode. Child reports of higher parental negativity about the regimen were associated with increased odds of experiencing a DKA episode. Reports of who in the family was responsible for the diabetes regimen were not related to episodes of DKA. Conclusions/Implications: Findings suggested that family factors play a significant role in the occurrence or absence of DKA in children's long-term management of diabetes. Future intervention efforts should focus on warmth, caring, and negativity when children and their parents are problem solving and communicating about the diabetes regimen. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In-situ transmission electron microscopy studies of polymer–carbon nanotube composite deformation

This paper demonstrates the viability of in-situ transmission electron microscopy for studying the deformation mechanisms of polymer nano-composites. In-situ straining studies are performed on carbon multiwalled nanotube (MWNT)–polystyrene composite films. The experiments show that load transfer across the nanotube–polystyrene interface is operative well into the plastic deformation regime of the composite film. The MWNTs are observed to bridge cracks propagating through the polystyrene, providing closure stresses across the crack wake. Although some MWNTs fracture by either a sword-in-sheath mechanism or transverse shear fracture, most of the MWNTs eventually debond at the MWNT–polymer interface and subsequently pull out of the matrix.     

Effect of Cr additions on the electrical properties of Ni–BaTiO3 ultra-thin multilayer capacitors

Multilayer ceramic capacitors based on BaTiO₃ dielectric compositions and Ni inner electrodes have complex interfacial reactions that impact the continuity of the inner electrode microstructure. Previously we demonstrated that through the addition of Cr to Ni, a significant improvement in the continuity of ultra-thin Ni electrodes in Ni–BaTiO₃ multilayer capacitors could be achieved. Here, the effect of the Cr addition to the nickel electrode pastes is studied with regard to the electrical properties. Low-field electrical measurements demonstrate no major differences between Cr doped Ni and undoped Ni. However, high-field measurements show a significant decrease to the total capacitor resistance. Under a critical electrical bias the conductivity significantly increases due to a Fowler–Nordheim tunneling conduction though the interfacial Schottky barrier at the dielectric–electrode interface; the onset voltage of this conduction is much lower than with the undoped nickel. Based on these results, we evaluate criteria for the selection of an appropriate refractory metal in order to improve the Ni electrode continuity.     

Discovery of Adamantyl Ethanone Derivatives as Potent 11β‐Hydroxysteroid Dehydrogenase Type 1 (11β‐HSD1) Inhibitors

11β‐Hydroxysteroid dehydrogenases (11β‐HSDs) are key enzymes regulating the pre‐receptor metabolism of glucocorticoid hormones. The modulation of 11β‐HSD type 1 activity with selective inhibitors has beneficial effects on various conditions including insulin resistance, dyslipidemia and obesity. Inhibition of tissue‐specific glucocorticoid action by regulating 11β‐HSD1 constitutes a promising treatment for metabolic and cardiovascular diseases. A series of novel adamantyl ethanone compounds was identified as potent inhibitors of human 11β‐HSD1. The most active compounds identified ( 52 , 62 , 72 , 92 , 103 and 104 ) display potent inhibition of 11β‐HSD1 with IC₅₀ values in the 50–70 nM range. Compound 72 also proved to be metabolically stable when incubated with human liver microsomes. Furthermore, compound 72 showed very weak inhibitory activity for human cytochrome P450 enzymes and is therefore a candidate for in vivo studies. Comparison of the publicly available X‐ray crystal structures of human 11β‐HSD1 led to docking studies of the potent compounds, revealing how these molecules may interact with the enzyme and cofactor.     

Incremental Validity of New Clinical Assessment Measures.

The authors address conceptual and methodological foundations of incremental validity in the evaluation of newly developed clinical assessment measures. Incremental validity is defined as the degree to which a measure explains or predicts a phenomenon of interest, relative to other measures. Incremental validity can be evaluated on several dimensions, such as sensitivity to change, diagnostic efficacy, content validity, treatment design and outcome, and convergent validity. Indices of incremental validity can vary depending on the criterion measures, comparison measures, and individual differences in samples. The authors review the rationale for, principles, and methods of incremental validation, including the selection of comparison and criterion measures, and address data analytic strategies and the conditional nature of incremental validity evaluations in the selection of measures. Incremental validity contributes to, but is different from, cost-benefits, which reflect the cost of acquiring the data and the benefits from the data. The impact of an incremental validity index on whether a measure is selected will be moderated by the cost of acquiring the new data, the importance of the measured phenomenon, and the clinical utility of the new data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Water industry asset management: a proposed service-performance model for investment

The water industry in England and Wales has developed over the last century, from small organisations serving local communities to large integrated companies in private ownership, overseen by a government regulator. Asset management practice has developed greatly in the 17 years since privatisation, with companies able to plan their operations and investment as they believe appropriate for the provision of customer services, subject to justifying their plans to the economic, quality and environmental regulators. Investment has flowed into the industry to replace deteriorated assets and to improve the quality of drinking water and rivers. The asset base is complex and, with a replacement value of approximately £231 billion at the 2002–2003 price base index suitable approaches are required to ensure that both the water service and the sewerage service are delivered at the most appropriate long‐term cost. The 2004 UK water industry price review was supported by the introduction of a Capital Maintenance Planning Common Framework to help companies understand and explain their maintenance investment requirement. In this paper, a service‐performance model is proposed to improve managers' understanding of the way in which businesses and the environment change over time, taking account of maintenance and other strategic requirements. Although developed with the water industry in mind, the model is equally applicable to other asset‐intensive industries.     

Editorial

In this month's issue of Filtration+Separation we focus on two of the biggest areas of growth for filtration and separation, namely membranes technology and their application in the treatment of water and wastewater. Anthony Bennett reviews recent developments in reverse osmosis (RO) technology and discusses their contribution to bringing down total costs of water treatment project s. Ross Severn from Aquator Group presenting long term operating data from MBR plants in the UK and Ireland that incorporate submerged plate membrane technology, providing an interesting insight into operation and maintenance issues faced by plant operators. Continuing the membrane and wastewater treatment theme we present a synopsis of the 'Membranes for Industrial Wastewater Recovery and Re-use' by Drs Simon Judd and Bruce Jefferson (Cranfield University, UK), that looks at the pros and cons of using membrane systems for the recovery and re-use of process wastewater.     

Interactive training versus reading to teach respiratory protection.

A tenet of behavioral education is that interactive training produces superior retention compared with reading. However, this has not often been directly tested and never with practical occupational information in working adults. Adults from diverse occupational backgrounds learned the principles of proper respiratory protection presented (a) in a book, (b) on a computer monitor, (c) through interactive computerized training consisting of textual information and illustrative pictures followed by quizzes and feedback, or (d) passively viewing the information and quizzes in Condition c on a computer monitor. Interactive training produced significantly more correct test answers at immediate posttraining, 1 week, and 2 months. This study demonstrated the superiority of interactive training for teaching occupational safety and health information in working adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)