A Computer Proof of a Series Evaluation in Terms of Harmonic Numbers

 A fruitful interaction between a new randomized WZ procedure and other computer algebra programs is illustrated by the computer proof of a series evaluation that originates from a definite integration problem. Received: April 9, 2002 Keywords: Computer algebra, Hypergeometric summation, Definite integration, WZ method. The first author was supported in part by NSF grant DMS-0103897. The third author was supported by SFB grant F1305 of the Austrian FWF.     

Safety-relevant mode confusions—modelling and reducing them

Mode confusions are a significant safety concern in safety-critical systems, for example in aircraft. A mode confusion occurs when the observed behaviour of a technical system is out of sync with the user's mental model of its behaviour. But the notion is described only informally in the literature. We present a rigorous way of modelling the user and the machine in a shared-control system. This enables us to propose precise definitions of ‘mode’ and ‘mode confusion’ for safety-critical systems. We then validate these definitions against the informal notions in the literature. A new classification of mode confusions by cause leads to a number of design recommendations for shared-control systems. These help in avoiding mode confusion problems. Our approach supports the automated detection of remaining mode confusion problems. We apply our approach practically to a wheelchair robot.     

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Ohne Zusammenfassung Eingegangen am 04.08.1996, in überarbeiteter Form am 06.05.1997     

Solubility of Zn and Pb in liquid iron and their partition between liquid iron and selected steelmaking slag systems

The use of Zn- and Pb-contaminated scrap in steelmaking has led to a significant increase of the zinc and lead contents in dusts and sludges, especially produced in the electric arc furnace melting shops. To understand the behaviour of Zn and Pb, fundamental research on the thermodynamics and kinetics of zinc and lead reactions under steelmaking conditions is helpful. In the first part of the present work, the solubilities of lead and zinc in iron are discussed. Furthermore, the influence of several alloying elements, such as carbon, oxygen, sulfur and chromium on the dissolution behaviour of Zn and Pb was examined and compared with former studies. Measurements of the solubility of lead in liquid iron were made at elevated temperatures in the systems Fe-Pb-O, Fe-Pb-C and Fe-Pb-Cr under argon in a gas-tight Tammann furnace. An increase of lead solubility was found with increasing temperature and increasing oxygen content. On the other hand, higher contents of carbon and chromium led to lower solubilities of lead in liquid iron. In the second part, the partition ratios of zinc and lead between liquid iron and various selected slag compositions were investigated. It is shown that zinc partition is determined by oxygen activity and slag basicity. In SiO₂-saturated slags, the partition ratio of zinc is considerably higher than in CaO-saturated slags. In comparison, the partition ratio of lead is significantly lower under the same experimental conditions.     

The Role of TKS5 in Chromosome Stability and Bladder Cancer Progression

TKS5 promotes invasion and migration through the formation of invadopodia in some tumour cells, and it also has an important physiological function in cell migration through podosome formation in various nontumour cells. To date, the role of TKS5 in urothelial cells, and its potential role in BC initiation and progression, has not yet been addressed. Moreover, the contribution of TKS5 to ploidy control and chromosome stability has not been reported in previous studies. Therefore, in the present study, we wished to address the following questions: (i) Is TKS5 involved in the ploidy control of urothelial cells? (ii) What is the mechanism that leads to aneuploidy in response to TKS5 knockdown? (iii) Is TKS5 an oncogene or tumour-suppressor gene in the context of BC? (iv) Does TKS5 affect the proliferation, migration and invasion of BC cells? We assessed the gene and protein expressions via qPCR and Western blot analyses in a set of nontumour cell strains (Y235T, HBLAK and UROtsa) and a set of BC cell lines (RT4, T24, UMUC3 and J82). Following the shRNA knockdown in the TKS5-proficient cells and the ectopic TKS5 expression in the cell lines with low/absent TKS5 expression, we performed functional experiments, such as metaphase, invadopodia and gelatine degradation assays. Moreover, we determined the invasion and migration abilities of these genetically modified cells by using the Boyden chamber and wound-healing assays. The TKS5 expression was lower in the bladder cancer cell lines with higher invasive capacities (T24, UMUC3 and J82) compared to the nontumour cell lines from human ureter (Y235T, HBLAK and UROtsa) and the noninvasive BC cell line RT4. The reduced TKS5 expression in the Y235T cells resulted in augmented aneuploidy and impaired cell division. According to the Boyden chamber and wound-healing assays, TKS5 promotes the invasion and migration of bladder cancer cells. According to the present study, TKS5 regulates the migration and invasion processes of bladder cancer (BC) cell lines and plays an important role in genome stability.     

Failure to find homology in rat, cat, and monkey for functions of a subcortical structure in avoidance conditioning.

Notes that electrolytic lesions of the centrum-medianum and parafascicularis complex of the thalamus produce, in the rat, large deficits of both acquisition and retention of active-avoidance responses, especially in the 2-way shuttle-box test. The effect of such lesions on 26 male cats and 6 male and 2 female macaques was examined. It was found that lesions in the cat did not produce significant effects, either with acoustical or visual CS, during postoperative relearning. Moreover, rate of extinction was not affected. Negative results were also found in monkeys. These lesions did not modify the threshold of flinch or jump responses to electric shock in either species. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comment: Process-dissociation measurement models: Threshold theory or detection theory?

Several methods to account for response biases in the process-dissociation procedure have been proposed. A. P. Yonelinas and L. L. Jacoby (1996) have favored a dual-process, signal-detection model (DPSDM) and have claimed that threshold-based models such as the extended measurement model (EMM) suggested by A. Buchner, E. Erdfelder, and B. Vaterrodt-Plünnecke (1995) should be rejected because threshold models are inconsistent with nonlinear receiver operating characteristics (ROCs) as obtained from confidence ratings. Their claim is shown to be incorrect. An EMM variant for confidence ratings is developed that accounts perfectly for nonlinear ROCs. It is demonstrated that, in contrast, the DPSDM favored by Yonelinas and Jacoby (1996) cannot fit the ROC data of 2 of the 3 experiments reported by A. P. Yonelinas (1994). Further, it is argued that experimental manipulations of response biases result in more thorough tests of process-dissociation models than confidence ratings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)