Unbalanced quadriphase demodulator

A new and improved apparatus and method are described for demodulation of quaternary phase shift keyed (QPSK) data, particularly unbalanced QPSK. Phase adjustment of the output of a phase locked loop local oscillator is performed to reduce sensitivity to amplitude variations internal to the demodulator

Enforcing QVT-R with mu-calculus and games

Abstract. QVT-R is the standard Object Management Group bidi-rectional transformation language. In previous work, we gave a precise game-theoretic semantics for the checkonly semantics of QVT-R trans-formations, including the recursive invocation of relations which is al-lowed and used, but not defined, by the QVT standard. In this paper, we take up the problem of enforce semantics, where the standard at-tempts formality, but at crucial points lapses into English. We show that our previous semantics can be extended to enforce mode, giving a precise semantics taking the standard into account.

Technicians and Dentists: A catch 22 situation?

Dental technicians who regularly receive poor quality impressions and records are often faced with professional and ethical concerns as to how to handle the situation. They may choose to complete the task to the best of their abilities. Other options are to alter the casts to try to improve the situation and then complete the prescription, contact the dentist and discuss the issue, contactthe patient, contact the medical aid, report the practitioner to the HPCSA, or refuse to do the work. Their latter actions have potentially negative implications for them, and will certainly sour working relationships. At worst, they may lose the dentist’s support. This paper explores ways in which dentists and techniciains can foster collegial and mutually beneficial relationships from early on in their careers. This will not only promote better communication, and improve the quality of work produced by them, but it will also serve the best interests of their patients and the profession as a whole

Punishment insensitivity emerges from impaired contingency detection, not aversion insensitivity or reward dominance

© 2019, eLife Sciences Publications Ltd. All rights reserved. Our behaviour is shaped by its consequences – we seek rewards and avoid harm. It has been reported that individuals vary markedly in their avoidance of detrimental consequences, i.e. in their sensitivity to punishment. The underpinnings of this variability are poorly understood; they may be driven by differences in aversion sensitivity, motivation for reward, and/or instrumental control. We examined these hypotheses by applying several analysis strategies to the behaviour of rats (n = 48; 18 female) trained in a conditioned punishment task that permitted concurrent assessment of punishment, reward-seeking, and Pavlovian fear. We show that punishment insensitivity is a unique phenotype, unrelated to differences in reward-seeking and Pavlovian fear, and due to a failure of instrumental control. Subjects insensitive to punishment are afraid of aversive events, they are simply unable to change their behaviour to avoid them

Large scale related effects on the determination of plant communities and relationships with environmental variables

The influence of scale on the discernment of plant community patterns was examined using vegetation-environment data collected from a subalpine wet meadow in south-coastal British Columbia. Species cover data were recorded in 225, 0.25 m2quadrats systematically located at 5m intervals in a 40 m x 120 m sampling grid. Environmental data consisted of quadrat elevations as well as measured and kriged estimates of five soil variables (carbon content, pH, electrical conductivity, percent sand, and percent clay). Sampling scale was adjusted by aggregating neighbouring quadrats into composite sampling units; analytical scale was altered by varying the intercept level in dendrograms from minimum increase of sum of squares cluster analysis of the vegetation data corresponding to the different sampling scales. The resulting classifications were evaluated for their ability to explain variation in the vegetation data and in the environmental data. The vegetation variation explained by the classifications was highest at the smallest sampling scale indicating that vegetation heterogeneity is fine grained. In contrast, the environmental variation explained was higher for the classifications based on the larger composite sampling units implying a coarser scaling of abiotic conditions within the study area. These results were consistent with the recognition of three main zones along a drainage gradient within the sampling grid. upper mixed-forb, middle heath, and lower sedge. There was also evidence that the orientation of rectangular sampling units parallel to the drainage gradient leads to higher levels of explained variation. This study reaffirms the need for careful consideration of alternatives both in field sampling and analytical phases of vegetation research to ensure that description and interpretation of patterns adequately address study objectives and that vegetation-environment relationships are more completely investigated from a hierarchical perspective

Tight junction dynamics: the role of junctional adhesion molecules (JAMs)

Junctional adhesion molecules (JAMs) are a family of adhesion molecules localized at the tight junction of polarized cells and on the cell surface of leukocytes. The last 20years of research in this field has shown that several members of the family play an important role in the regulation of cell polarity, endothelium permeability and leukocytes migration. They mediate these pleiotropic functions through a multitude of homophilic and heterophilic interactions with intrafamily and extrafamily partners. In this article, we review the current status of the JAM family and highlight their functional role in tight junction dynamics and leukocyte transmigration

From coinductive proofs to exact real arithmetic: theory and applications

Based on a new coinductive characterization of continuous functions we extract certified programs for exact real number computation from constructive proofs. The extracted programs construct and combine exact real number algorithms with respect to the binary signed digit representation of real numbers. The data type corresponding to the coinductive definition of continuous functions consists of finitely branching non-wellfounded trees describing when the algorithm writes and reads digits. We discuss several examples including the extraction of programs for polynomials up to degree two and the definite integral of continuous maps

Implementing QVT-R bidirectional model transformations using alloy

QVT Relations (QVT-R) is the standard language proposed by the OMG to specify bidirectional model transformations. Unfortunately, in part due to ambiguities and omissions in the original semantics, acceptance and development of effective tool support has been slow. Recently, the checking semantics of QVT-R has been clarified and formalized. In this paper we propose a QVT-R tool that complies to such semantics. Unlike any other existing tool, it also supports meta-models enriched with OCL constraints (thus avoiding returning ill-formed models), and proposes an alternative enforcement semantics that works according to the simple and predictable “principle of least change”. The implementation is based on an embedding of both QVT-R transformations and UML class diagrams (annotated with OCL) in Alloy, a lightweight formal specification language with support for automatic model finding via SAT solving.Fundação para a Ciência e a Tecnologi