A language for behavioural modelling of architectural patterns

The complexity of interactions governing the coordination of loosely-coupled services, which forms the core of current software, brought behavioural issues up to the front of architectural concerns. This paper takes such a challenge seriously by lifting typical behaviour modelling techniques to the specification of both types and instances of architectural patterns in which the later ones are connected by ports that behave according to a water flow metaphor. A specific language is introduced for this purpose as well as a translator to mCRL2 so that the simulation and analysis techniques available in the corresponding toolset can be used to reason about (the behavioural layer of) software architectures. The approach is illustrated in a few examples(undefined

Verifying bigraphical models of architectural reconfigurations

ARCHERY is an architectural description language for modelling and reasoning about distributed, heterogeneous and dynamically reconfigurable systems. This paper proposes a structural semantics for ARCHERY, and a method for deriving labelled transition systems (LTS) in which states and transitions represent configurations and reconfiguration operations, respectively. Architectures are modelled by bigraphs and their dynamics by parametric reaction rules. The resulting LTSs can be regarded as Kripke frames, appropriate for verifying reconfiguration constraints over architectural patterns expressed in a modal logic. The derivation method proposed here applies Leifer's approach twice, and combines the results of each application to obtain a label representing a reconfiguration operation and its actual parameters. Labels obtained in this way are minimal and yield LTSs in which bisimulation is a congruence.FC

Towards rigorous analysis of open source software

Workshop proceedings with local publication by the University of OsloThis paper discusses the (often hidden) potential of Open Source Software development to resort to, benefit from and cross-fertilize formal engineering methods, whose role is indisputable in the production of trustworthy software components. A strategy addressing the incorporation of formal verification methods in the Open Source Software lifecycle, in a somewhat less conventional way — that of assisting the re-engineering process of running code — is proposed.Fundação para a Ciência e a Tecnologia (FCT

Analysing tactics in architectural patterns

We present an approach to analyse the application of tactics in architectural patterns. We define and illustrate the approach by resorting to Archery, a language for specifying, analysing and verifying architectural patterns. The approach consists of characterising the design principles of an architectural pattern as constraints, expressed in the language, and then, establishing a refinement relation based on their satisfaction. The application of tactics preserving refinement preserves the original design principles expressed themselves as constraints for the architectural pattern. The paper’s focus on fault-tolerance tactics, and identifies a set of requirements for a semantic framework characterising them. Model transformations to represent their application are discussed and illustrated through two case studies.FC

A perspective on architectural re-engineering

Continuous evolution towards very large, heterogeneous, highly dynamic computing systems entails the need for sound and flexible approaches to deal with system modification and re-engineering. The approach proposed in this paper combines an analysis stage, to identify concrete patterns of interaction in legacy code, with an iterative re-engineering process at a higher level of abstraction. Both stages are supported by the tools CoordPat and Archery, respectively. Bi-directional model transformations connecting code level and design level architectural models are defined. The approach is demonstrated in a (fragment of a) case study.This work is funded by the ERDF through the Programme COMPETE and by FCT, the Portuguese Foundation for Science and Technology, under contract FCOMP-01-0124-FEDER-028923

Is the Toxicity of Salvage Prostatectomy Related to the Primary Prostate Cancer Therapy Received?

PURPOSE: To compare the toxicity profile and oncological outcome of salvage radical prostatectomy (SRP) following focal therapy (FT) versus SRP after radiation therapies (RT) - external beam radiation therapy (EBRT) or brachytherapy (BT). MATERIALS AND METHODS: Data concerning all men undergoing SRP for recurrent prostate cancer after either FT, EBRT or BT were retrospectively collected from 4 high volume surgical centres. The primary outcome measure of the study was toxicity of SRP characterized by any 30-day post-operative Clavien-Dindo complication rate, 12-month continence rate and 12-month potency rate. The secondary outcome was oncological outcome after SRP including positive margin rate and 12-month biochemical recurrence (BCR) rate. BCR was estimated using Kaplan-Meier methods and significant differences were calculated using a log rank test. Median follow-up time was 29.5 months. RESULTS: Between April 2007 and September 2018, 185 patients underwent SRP of which 95 had SRP after FT and 90 had SRP after RT, either EBRT or BT. SRP after RT was associated with a significantly higher 30-day Clavien-Dindo I-IV complication rate (34% vs 5%, p<0.001). At 12 months following surgery, patients undergoing SRP after FT had significantly better continence (SRP after FT:83% pad-free vs RT:49%) while potency outcomes were similar (FT:14% vs RT:11%). Men undergoing SRP after RT had a significantly higher stage and grade of disease together with a higher positive surgical margin rate (37% vs 13%, p=0.001). 3-year BCR after FT was 35% compared to 32% after RT, p=0.76. In multivariable analysis, men undergoing SRP after FT experienced a higher risk of BCR (HR 0.36 [0.18-0.82], p<0.005). CONCLUSIONS: This multicentre study demonstrates the toxicity of SRP in terms of perioperative complications and long-term urinary continence recovery is dependent on initial primary prostate cancer therapy received with men undergoing SRP after FT experiencing lower postoperative complication rates and better urinary continence outcomes

Nanostructured Europium Oxide thin films deposited by pulsed laser ablation of a metallic target in a He buffer atmosphere

Nanostrucured Europium oxide and hydroxide films were obtained by pulsed Nd:Yag (532 nm) laser ablation of an Europium metallic target, in the presence of a 1 mbar Helium buffer atmosphere. Both the produced film and the ambient plasma were characterized. The plasma was monitored by an electrostatic probe, for plume expansion in vacuum or in the presence of the buffer atmosphere. The time evolution of the ion saturation current was obtained for several probe to substrate distances. The results show the splitting of the plume into two velocity groups, being the lower velocity profile associated with metal cluster formation within the plume. The films were obtained in the presence of helium atmosphere, for several target to substrate distances. They were analyzed by Rutherford backscattering spectrometry (RBS), X-Ray Diffraction (XRD) and Atomic Force Microscopy, for samples as-deposited and treated at 600 degrees C in air. The results show that the as-deposited samples are amorphous and have chemical composition compatible with Europium hydroxide. The thermally treated samples show X-Ray diffraction peaks of Eu_2O_3, with chemical composition showing excess oxygen. Film nanostructuring was shown to be strongly correlated to cluster formation, as shown by velocity splitting in probe current versus time plots.Comment: 7 pages, 11 figures, 31 reference

The divergent eukaryote Trichomonas vaginalis has an m7G cap methyltransferase capable of a single N2 methylation

Eukaryotic RNAs typically contain 5′ cap structures that have been primarily studied in yeast and metazoa. The only known RNA cap structure in unicellular protists is the unusual Cap4 on Trypanosoma brucei mRNAs. We have found that T. vaginalis mRNAs are protected by a 5′ cap structure, however, contrary to that typical for eukaryotes, T. vaginalis spliceosomal snRNAs lack a cap and may contain 5′ monophophates. The distinctive 2,2,7-trimethylguanosine (TMG) cap structure usually found on snRNAs and snoRNAs is produced by hypermethylation of an m7G cap catalyzed by the enzyme trimethylguanosine synthase (Tgs). Here, we biochemically characterize the single T. vaginalis Tgs (TvTgs) encoded in its genome and demonstrate that TvTgs exhibits substrate specificity and amino acid requirements typical of an RNA cap-specific, m7G-dependent N2 methyltransferase. However, recombinant TvTgs is capable of catalysing only a single round of N2 methylation forming a 2,7-dimethylguanosine cap (DMG) as observed previously for Giardia lamblia. In contrast, recombinant Entamoeba histolytica and Trypanosoma brucei Tgs are capable of catalysing the formation of a TMG cap. These data suggest the presence of RNAs with a distinctive 5′ DMG cap in Trichomonas and Giardia lineages that are absent in other protist lineages