Shuffle–based verification of component compatibility

An extension of earlier work on component compatibility is described in this paper. Similarly as before, the behavior of components is specified by component interface languages, and the shuffle operation is introduced to represent possible interleavings of service requests that originate at several concurrent components. The paper shows that the verification of component compatibility is possible without the exhaustive analysis of the state space of interacting components. Exhaustive analysis of state spaces was the basis of earlier approaches to compatibility verification

Model Fusion for the Compatibility Verification of Software Components

Similarly as in earlier work on component compatibility, the behavior of components is specified by component interface languages, defined by labeled Petri nets. In the case of composition of concurrent components, the requests from different components can be interleaved, and - as shown earlier - such interleaving can result in deadlocks in the composed system even if each pair of interacting components is deadlock–free. Therefore the elements of a component–based system are considered compatible only if the composition is deadlock–free. This paper formally defines model fusion, which is a composition of net models of individual components that represents the interleaving of interface languages of interacting components. It also shows that the verification of component compatibility can avoid the exhaustive analysis of the composed state space

Service Renaming in Component Composition

In component-based systems, the behavior of components is usually described at component interfaces and the components are characterized as requester (active) and provider (reactive) components. Two interacting components are considered compatible if all possible sequences of services requested by one component can be provided by the other component. This concept of component compatibility can be extended to sets of interacting components, however, in the case of several requester components interacting with one or more provider components, as is typically the case of cleint-server applications, the requests from different components can be interleaved and then verifying component compatibility must take into account all possible interleavings of requests. Such interleaving of requests can lead to unexpected behavior of the composed system, e.g. a deadlock can occur. Service renaming is proposed as a method of systematic eliminating of such unexpected effects and streamlining component compositions

Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years

Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately1 and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial–interglacial cycles2,3 with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance

Colonoscopic-Assisted Laparoscopic Wedge Resection for Colonic Lesions A Prospective Multicenter Cohort Study (LIMERIC-Study)

Objective: The aim of this study was to evaluate the safety and efficacy of a modified CAL-WR. Summary Background Data: The use of segmental colectomy in patients with endoscopically unresectable colonic lesions results in significant morbidity and mortality. CAL-WR is an alternative procedure that may reduce morbidity. Methods: This prospective multicenter study was performed in 13 Dutch hospitals between January 2017 and December 2019. Inclusion criteria were (1) colonic lesions inaccessible using current endoscopic resection techniques (judged by an expert panel), (2) non-lifting residual/recurrent adenomatous tissue after previous polypectomy or (3) an undetermined resection margin after endoscopic removal of a low-risk pathological T1 (pT1) colon carcinoma. Thirty-day morbidity, technical success rate and radicality were evaluated. Results: Of the 118 patients included (56% male, mean age 66 years, standard deviation +/- 8 years), 66 (56%) had complex lesions unsuitable for endoscopic removal, 34 (29%) had non-lifting residual/recurrent adenoma after previous polypectomy and 18 (15%) had uncertain resection margins after polypectomy of a pT1 colon carcinoma. CAL-WR was technically successful in 93% and R-0 resection was achieved in 91% of patients. Minor complications (Clavien-Dindo i-ii) were noted in 7 patients (6%) and an additional oncologic segmental resection was performed in 12 cases (11%). Residual tissue at the scar was observed in 5% of patients during endoscopic follow-up. Conclusions: CAL-WR is an effective, organ-preserving approach that results in minor complications and circumvents the need for major surgery. CAL-WR, therefore, deserves consideration when endoscopic excision of circumscribed lesions is impossible or incomplete.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Mediterranean tephrostratigraphy and peri-Tyrrhenian explosive activity revaluated in light of the 430-365 ka record from Fucino Basin (central Italy)

Accurately reconstructing the scale and timing of dynamic processes, such as Middle-Late Pleistocene explosive volcanism and rapid climatic changes, requires rigorous and independent chronological constraints. In this framework, the study of distal volcanic ash layers, or tephra, transported and deposited over wide regions during explosive volcanic eruptions, is increasingly being recognised as a fundamental chronostratigraphic tool for addressing these challenging issues. Here we present a high-resolution distal tephra record preserved in the lacustrine sedimentary succession of the Fucino Basin, central Italy. The investigated record spans the 430-365 ka time interval, covering the entirety of Marine Isotope Stage 11 (MIS 11), and provides important insights into peri-Tyrrhenian potassic explosive volcanism from sources located in central Italy against a backdrop of Mediterranean palaeooclimate records. The succession of ash fall events of this time interval is reconstructed through a detailed lithostratigraphic, geochemical and 40Ar/39Ar geochronological characterization of the deposits preserved as discrete layers in the Fucino F4-F5 sediment core. This work is complemented by similarly detailed characterization of selected proximal pyroclastic units from the peri-Tyrrhenian potassic volcanoes. Geochemical fingerprinting of the tephra deposits by means of their major, minor and trace elements and Sr isotope composition indicates that all the thirty-two investigated ash layers derived from the peri-Tyrrhenian potassic volcanoes. The stratigraphically continuous succession of the Fucino tephra layers allowed the development of a fully independent, 40Ar/39Ar age-constrained, Bayesian age-depth model for the investigated time interval. The age-model allows us to establish modelled ages for the tephra layers within the succession that are not directly dated. The resulting dated tephra record clearly reveals a highly time resolved and previously unparalelled chronicle of explosive activity from the Vulsini, Vico, Sabatini, Colli Albani and Roccamonfina volcanic complexes. Our study provides a benchmark and valuable geochemical and geochronological dataset to be used as a reference for any future development and application of the tephrostratigraphic methods across the central Mediterranean area both during the investigated 430-365 ka time interval, and deeper in time. This contribution underlines the importance of integrating proximal and distal sedimentary records to more accurately establish long-term and comprehensive volcanic eruption records

The Fucino 250-170 ka tephra record. New insights on peri-Tyrrhenian explosive volcanism, central mediterranean tephrochronology, and timing of the MIS 8-6 climate variability.

The Fucino Basin, central Italy, with its long and continuous history of Quaternary sediment accumulation, is one of the richest Mediterranean Middle Pleistocene tephra records. Here, we present a new detailed investigation of tephra layers (tephras) of the 250–170 thousand years before present (ka) interval, corresponding to the entire Marine Isotope Stage (MIS) 7 and parts of the MIS 8 and MIS 6. The investigated tephras have been characterised in terms of major, minor and trace elements, Sr–Nd isotopic compositions and 40Ar/39Ar ages. For correlation purposes, glass compositions and several new 40Ar/39Ar ages of selected proximal pyroclastic units spanning the same temporal interval from Vulsini (Latera Volcanic Complex), Sabatini, and Vico volcanic systems, central Italy, were measured. The late MIS 8-early MIS 6 Fucino tephras were backtracked to their corresponding volcanic sources, which include the Vulsini, Vico, Sabatini, Roccamonfina, Ischia and Campi Flegrei volcanic systems. While some of these tephras have been correlated to specific eruption units, other layers are currently not documented or described in near-vent sections, thus highlighting previously unrecognised events generated by these volcanic systems. Furthermore, the new high precision 40Ar/39Ar ages provide improved temporal constraints for Fucino making it one of the most detailed and chronologically best constrained tephra records for central Mediterranean MIS 7 tephrochronology. The Fucino record thus provides new integrative information for reconstructing the explosive history of Italian volcanoes during the investigated time interval. Furthermore, the geochronological constraints provide the basis for future paleoclimatic investigations at local and regional scale