Efficiency implications of open source commonality and reuse

This paper analyzes the reuse choices made by open source developers and relates them to cost efficiency. We make a distinction between the commonality among applications and the actual reuse of code. The former represents the similarity between the requirements of different applications and, consequently, the functionalities that they provide. The latter represents the actual reuse of code. No application can be maintained for ever. A fundamental reason for the need for periodical replacement of code is the exponential growth of costs with the number of maintenance interventions. Intuitively, this is due to the increasing complexity of software that grows in both size and coupling among different modules. The paper measures commonality, reuse and development costs of 26 open-source projects for a total of 171 application versions. Results show that reuse choices in open-source contexts are not cost efficient. Developers tend to reuse code from the most recent version of applications, even if their requirements are closer to previous versions. Furthermore, the latest version of an application is always the one that has incurred the highest number of maintenance interventions. Accordingly, the development cost per new line of code is found to grow with reuse

The onset of an eruption: selective assimilation of hydrothermal minerals during pre-eruptive magma ascent of the 2010 summit eruption of Eyjafjallajokull volcano, Iceland

The complex processes occurring in the initial phases of an eruption are often recorded in the products of its opening stage, which are usually characterized by small volume and limited dispersal, and thus generally poorly studied. The 2010 eruption of Eyjafjallajökull (Iceland) represents a unique opportunity for these investigations thanks to the good preservation of tephra deposits within the ice/snow pack. A detailed geochemical investiga- tion on the glassy groundmass of single ash clasts disclosed a population of fragments with unusual high 87Sr/86Sr (up to 0.70668) for Icelandic magmatism, and anomalous elemental composition with respect to most of the ju- venile material of the eruption. This suggests that during its rise, before intruding into the ice cover, magma at a dyke tip selectively assimilated hydrothermal minerals with seawater-related, high-Sr isotopic ratios (zeolites, silica phases, anhydrite) hosted in altered volcanic/epiclastic rocks. According to the observed precursory seismic- ity, only restricted to few hours before the onset of the eruption, this process could have accompanied subcritical aseismic fracture opening during the days before the eruption, possibly related to stress corrosion-cracking pro- cesses, which enhanced the partial dissolution/melting and subsequent selective assimilation of the host rocks

Data on unveiling the occurrence of transient, multi-contaminated mafic magmas inside a rhyolitic reservoir feeding an explosive eruption (Nisyros, Greece)

This data article includes the description and the geochemical and mineralogical dataset of 67 pyroclastic rock samples from the Upper Pumice (UP) explosive activity of Nisyros volcano (eastern South Aegean Active Volcanic Arc). A detailed field and petrographic description of the studied outcrops and samples are reported, including representative photomicrographs and SEM images, whole-rock major and trace elements compositions of 31 representative samples and Sr-Nd isotope ratios on 22 selected samples. Analytical methods and conditions used for data acquisition are also reported. The UP eruption produced a stratigraphic sequence constituted by a basal fallout deposit, gradually substituted by pyroclastic density current (PDC) deposits; these are overlaid by a lag-breccia unit, and the sequence is closed by a grey ash flow level. The juvenile is mainly constituted by white-yellow, moderately crystalline pumice with rhyolitic composition and homogenous Sr-Nd isotope values. Variable amounts of dense, grey, crystalline juvenile lapilli clasts (CRC, Crystal-Rich Clast), with rounded shape and less evolved composition (andesite to dacite) are also present in the deposit. These mafic CRCs are peculiar due to their large variability in textures (from distinctive diktytaxitic to strongly fragmented structure without a defined fabric) and in the geochemical and isotopic composition. The data acquired were fundamental to reconstruct the complex and peculiar history of ascent, storage and differentiation/assimilation processes of these mafic melts before their intrusion into the shallow, rhyolitic magma chamber, with important implication on the possible eruption trigger during the more recent explosive phase of activity at Nisyros volcano. Moreover, the geochemical and isotopic analyses provide new original data to the general knowledge of the Aegean volcanics. All the data reported in this paper are related to the research article Braschi et al. (2022

High-precision in situ 87Sr/86Sr analyses through micro-sampling on solid samples: applications to Earth and Life Sciences

An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. In addition, we present three significant case studies for geological and life sciences, as examples of the various applications of microscale 87Sr/86Sr isotope ratios, concerning (i) the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece), (ii) the dynamics involved with the initial magma ascent during Eyjafjallajökull volcano’s (Iceland) 2010 eruption, which are usually related to the precursory signals of the eruption, and (iii) the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences

Novel large-range mitochondrial dna deletions and fatal multisystemic disorder with prominent hepatopathy

Hepatic involvement in mitochondrial cytopathies rarely manifests in adulthood, but is a common feature in children. Multiple OXPHOS enzyme defects in children with liver involvement are often associated with dramatically reduced amounts of mtDNA. We investigated two novel large scale deletions in two infants with a multisystem disorder and prominent hepatopathy. Amount of mtDNA deletions and protein content were measured in different post-mortem tissues. The highest levels of deleted mtDNA were in liver, kidney, pancreas of both patients. Moreover, mtDNA deletions were detected in cultured skin fibroblasts in both patients and in blood of one during life. Biochemical analysis showed impairment of mainly complex I enzyme activity. Patients manifesting multisystem disorders in childhood may harbour rare mtDNA deletions in multiple tissues. For these patients, less invasive blood specimens or cultured fibroblasts can be used for molecular diagnosis. Our data further expand the array of deletions in the mitochondrial genomes in association with liver failure. Thus analysis of mtDNA should be considered in the diagnosis of childhood-onset hepatopathies

ERNICA guidelines for the management of rectosigmoid Hirschsprung's disease

Background Hirschsprung's disease (HSCR) is a serious congenital bowel disorder with a prevalence of 1/5000. Currently, there is a lack of systematically developed guidelines to assist clinical decision-making regarding diagnostics and management. Aims This guideline aims to cover the diagnostics and management of rectosigmoid HSCR up to adulthood. It aims to describe the preferred approach of ERNICA, the European Reference Network for rare inherited and congenital digestive disorders. Methods Recommendations within key topics covering the care pathway for rectosigmoid HSCR were developed by an international workgroup of experts from 8 European countries within ERNICA European Reference Network from the disciplines of surgery, medicine, histopathology, microbiology, genetics, and patient organization representatives. Recommendation statements were based on a comprehensive review of the available literature and expert consensus. AGREE II and GRADE approaches were used during development. Evidence levels and levels of agreement are noted. Results Thirty-three statements within 9 key areas were generated. Most recommendations were based on expert opinion. Conclusion In rare or low-prevalence diseases such as HSCR, there remains limited availability of high-quality clinical evidence. Consensus-based guidelines for care are presented.Peer reviewe

ERNICA guidelines for the management of rectosigmoid Hirschsprung's disease

Background Hirschsprung's disease (HSCR) is a serious congenital bowel disorder with a prevalence of 1/5000. Currently, there is a lack of systematically developed guidelines to assist clinical decision-making regarding diagnostics and management. Aims This guideline aims to cover the diagnostics and management of rectosigmoid HSCR up to adulthood. It aims to describe the preferred approach of ERNICA, the European Reference Network for rare inherited and congenital digestive disorders. Methods Recommendations within key topics covering the care pathway for rectosigmoid HSCR were developed by an international workgroup of experts from 8 European countries within ERNICA European Reference Network from the disciplines of surgery, medicine, histopathology, microbiology, genetics, and patient organization representatives. Recommendation statements were based on a comprehensive review of the available literature and expert consensus. AGREE II and GRADE approaches were used during development. Evidence levels and levels of agreement are noted. Results Thirty-three statements within 9 key areas were generated. Most recommendations were based on expert opinion. Conclusion In rare or low-prevalence diseases such as HSCR, there remains limited availability of high-quality clinical evidence. Consensus-based guidelines for care are presented.Peer reviewe