Bilayered ceramic anterior restorations with reinforcement of the incisal edge by using lithium disilicate:A multicenter retrospective survival analysis with a maximum of 6-year follow-up

STATEMENT OF PROBLEM: The esthetics of anterior lithium disilicate restorations can be enhanced if the buccal aspect is layered with a feldspathic ceramic. However, whether fractures and chipping of this layer are a prevalent complication is unclear.PURPOSE: The purpose of this retrospective study was to evaluate the incidence of incisal fracture of a specially designed lithium disilicate reinforcement of the incisal edge for indirect anterior bilayered restorations on both teeth and implants.MATERIAL AND METHODS: A total of 924 anterior bilayered pressed lithium disilicate restorations in 324 patients and made in one dental laboratory were delivered by 4 restorative dentists. The restorations had the palatal side of the incisal edge in monolithic lithium disilicate and the facial side in feldspathic porcelain. The restorations were evaluated for survival and the occurrence of fracture or chipping. Survival analyses were performed by using the Kaplan-Meier and log rank (Mantel-Cox) tests (α=.05).RESULTS: Of the 924 restorations, 798 (236 complete crowns, 562 partial restorations) were placed on teeth and 126 on implants. The mean observation time was 38 months (3 to 72 months). The survival rate was 96.5%, with 14 failures occurring. The failures were fracture after dental trauma (n=5), ceramic fracture (n=1), debonding (n=6), poor shade match (n=1), and tooth loss (n=2). Restorations in patients with parafunctional habits and endodontically treated teeth showed a significant decrease in survival rate (P=.018). No significant differences were found between the survival of restorations on teeth and implants and between complete crowns and partial restorations (P=.021). No chipping was observed on any restorations in the study.CONCLUSIONS: Modified anterior bilayered ceramic restorations showed good survival rates, and no chipping was observed up to 6 years of follow-up. Parafunctional habits and endodontic treatment had a negative effect on the survival rate of restorations. The support of tooth or implant and the restoration type had no effect on the survival.</p

Normative Autonomy and Normative Co-ordination: Declarative Power, Representation, and Mandate

In this paper we provide a formal analysis of the idea of normative co-ordination. We argue that this idea is based on the assumption that agents can achieve flexible co-ordination by conferring normative positions to other agents. These positions include duties, permissions, and powers. In particular, we explain the idea of declarative power, which consists in the capacity of the power-holder of creating normative positions, involving other agents, simply by "proclaiming" such positions. In addition, we account also for the concepts of representation, namely the representative's capacity of acting in the name of his principal, and of mandate, which is the mandatee's duty to act as the mandator has requested. Finally, we show how the framework can be applied to represent the contract-net protocol. Some brief remarks on future research and applications conclude this contribution

Estudio de la influencia de la automatización en el proyecto arquitectónico

Estudio de la influencia de la automatización en el proyecto arquitectónic

To Recycle or Not to Recycle? An Intergenerational Approach to Nuclear Fuel Cycles

This paper approaches the choice between the open and closed nuclear fuel cycles as a matter of intergenerational justice, by revealing the value conflicts in the production of nuclear energy. The closed fuel cycle improve sustainability in terms of the supply certainty of uranium and involves less long-term radiological risks and proliferation concerns. However, it compromises short-term public health and safety and security, due to the separation of plutonium. The trade-offs in nuclear energy are reducible to a chief trade-off between the present and the future. To what extent should we take care of our produced nuclear waste and to what extent should we accept additional risks to the present generation, in order to diminish the exposure of future generation to those risks? The advocates of the open fuel cycle should explain why they are willing to transfer all the risks for a very long period of time (200,000 years) to future generations. In addition, supporters of the closed fuel cycle should underpin their acceptance of additional risks to the present generation and make the actual reduction of risk to the future plausible

Laboratory prediction of the requirement for renal replacement in acute falciparum malaria

BACKGROUND: Acute renal failure is a common complication of severe malaria in adults, and without renal replacement therapy (RRT), it carries a poor prognosis. Even when RRT is available, delaying its initiation may increase mortality. Earlier identification of patients who will need RRT may improve outcomes. METHOD: Prospectively collected data from two intervention studies in adults with severe malaria were analysed focusing on laboratory features on presentation and their association with a later requirement for RRT. In particular, laboratory indices of acute tubular necrosis (ATN) and acute kidney injury (AKI) that are used in other settings were examined. RESULTS: Data from 163 patients were available for analysis. Whether or not the patients should have received RRT (a retrospective assessment determined by three independent reviewers) was used as the reference. Forty-three (26.4%) patients met criteria for dialysis, but only 19 (44.2%) were able to receive this intervention due to the limited availability of RRT. Patients with impaired renal function on admission (creatinine clearance < 60 ml/min) (n = 84) had their laboratory indices of ATN/AKI analysed. The plasma creatinine level had the greatest area under the ROC curve (AUC): 0.83 (95% confidence interval 0.74-0.92), significantly better than the AUCs for, urinary sodium level, the urea to creatinine ratio (UCR), the fractional excretion of urea (FeUN) and the urinary neutrophil gelatinase-associated lipocalcin (NGAL) level. The AUC for plasma creatinine was also greater than the AUC for blood urea nitrogen level, the fractional excretion of sodium (FeNa), the renal failure index (RFI), the urinary osmolality, the urine to plasma creatinine ratio (UPCR) and the creatinine clearance, although the difference for these variables did not reach statistical significance. CONCLUSIONS: In adult patients with severe malaria and impaired renal function on admission, none of the evaluated laboratory indices was superior to the plasma creatinine level when used to predict a later requirement for renal replacement therapy

How (not) to measure bias in face recognition networks

Within the last years Face Recognition (FR) systems have achieved human-like (or better) performance, leading to extensive deployment in large-scale practical settings. Yet, especially for sensible domains such as FR we expect algorithms to work equally well for everyone, regardless of somebody's age, gender, skin colour and/or origin. In this paper, we investigate a methodology to quantify the amount of bias in a trained Convolutional Neural Network (CNN) model for FR that is not only intuitively appealing, but also has already been used in the literature to argue for certain debiasing methods. It works by measuring the "blindness" of the model towards certain face characteristics in the embeddings of faces based on internal cluster validation measures. We conduct experiments on three openly available FR models to determine their bias regarding race, gender and age, and validate the computed scores by comparing their predictions against the actual drop in face recognition performance for minority cases. Interestingly, we could not link a crisp clustering in the embedding space to a strong bias in recognition rates|it is rather the opposite. We therefore offer arguments for the reasons behind this observation and argue for the need of a less naive clustering approach to develop a working measure for bias in FR models

The design analogy: a model for moral problem solving

In this paper we explore an analogy between design and ethics, first drawn by Whitbeck. We investigate her claim that such an analogy can help to understand moral problems and aid us in dealing with them by suggesting strategies for addressing moral problems. We explore the nature of analogies, and extract criteria for what constitutes a 'good' analogy. We use some of the established knowledge about design and design reasoning to consider critically and to extend Whitbeck's design analogy. We establish the practical merits of the design analogy in a thought experiment, solving a moral problem in a manner that is closely modelled on a design method. Our conclusions include suggestions for further research and a fledgling vision of the future role of design methodology. We propose that the design analogy could be fruitful in shedding light on problem solving in various areas of human endeavour not traditionally associated with design. © 2006 Elsevier Ltd. All rights reserved