Software Ticks Need No Specifications

Software bugs cost time, money, and lives. They drive software research and development efforts, and are central to modern software engineering. Yet we lack a clear and general definition of what bugs are. Some bugs are defects, clearly defined as failures to meet some requirement or specification. However,there are many forms of undesirable program behaviour that are completely compatible with a typical program’s specification. In this paper, we argue that the lack of a criterion for identifying non-defect bugs is hampering the development of tools that find and fix bugs. We propose such a criterion, based on the idea of wasted effort, discuss how bugs that meet our definition of software ticks can complement defects, and sketch how our definition can help future work on software tools

System Identification of a Solar Tower Power Plant for Model Based Control

In this study, thermal models of solar tower power plant components for the purpose of model-based control are set up and fit to operational data of the solar tower in Jülich, Germany. Solar tower power plants provide renewable energy by concentrating solar radiance and converting the heat into electrical power in a power block. The technology inherently enables the use of thermal storages allowing the decoupling of power production and solar radiance. The volatile nature of the primary energy source, the sun, and the use of a thermal storage set challenges for the control of these systems compared to conventional power plants. Model-based control methods like model predictive control are promising for these power plants. For that a comprehensive model of the plant is needed. In future studies the performance of model based control is to be compared for physics based models and for data driven models based on neural networks. This study aims to provide physics-based models of the power plant’s components for a modular design of a solar tower power plant. Model reduction efforts are conducted in order to keep computational expenses down for optimization processes and to mitigate numerical issues when solving the system of equations. The models are fit to operational data by adjusting a chosen set of parameters. Moving horizon estimation and sequential quadratic least square programming are used to identify these sets of parameters. The systems of equations describing the dynamic behavior of the components is simulated using the do-mpc framework based on Casadi. For the automatic differentiation performed in Casadi, differentiable functions describing the thermodynamic properties of the fluids are needed. The thermodynamic properties have been approximated using polynomial functions. Their accuracy is evaluated for different degrees and domains. The results show that the methods for parameter identification are suitable and the simulations are able to reproduce the measured operational data. Sets of parameters for each simulated component are found and their accuracy is evaluated. The results show that the use of polynomials for steam property approximation as implemented in this study is very restricted for the simulation and optimization of large scale systems of differential algebraic equations. A comprehensive knowledge of the process and the accuracy of the polynomials in various domains is needed for their application. Simplifications made for model reduction efforts lower the model’s accuracy but enhance their computational performance. The effects of simplifications are analyzed and evaluated. This study aims to provide physics-based models of the power plant’s components for a modular design of a solar tower power plant. Model reduction efforts are conducted in order to keep computational expenses down for optimization processes and to mitigate numerical issues when solving the system of equations. The models are fit to operational data by adjusting a chosen set of parameters. Moving horizon estimation and sequential quadratic least square programming are used to identify these sets of parameters. The systems of equations describing the dynamic behavior of the components is simulated using the do-mpc framework based on Casadi. For the automatic differentiation performed in Casadi, differentiable functions describing the thermodynamic properties of the fluids are needed. The thermodynamic properties have been approximated using polynomial functions. Their accuracy is evaluated for different degrees and domains. The results show that the methods for parameter identification are suitable and the simulations are able to reproduce the measured operational data. Sets of parameters for each simulated component are found and their accuracy is evaluated. The results show that the use of polynomials for steam property approximation as implemented in this study is very restricted for the simulation and optimization of large scale systems of differential algebraic equations. A comprehensive knowledge of the process and the accuracy of the polynomials in various domains is needed for their application. Simplifications made for model reduction efforts lower the model’s accuracy but enhance their computational performance. The effects of simplifications are analyzed and evaluated

Klotho is a substrate for α-, β- and γ-secretase

AbstractKlotho is an anti-aging protein with different functions of the full-length membrane protein and the secreted hormone-like form. Using overexpression and knock-down approaches as well as embryonic fibroblasts of knock-out mice we present evidence that Klotho is shedded by the α-secretases ADAM10 and 17 as well as by the β-secretase β-APP cleaving enzyme 1. The remaining membrane-bound fragment is a substrate for regulated intramembrane proteolysis by γ-secretase. Our data suggest that therapeutic approaches targeting these proteases should be carefully analyzed for potential side effects on Klotho-mediated physiological processes

Combined Untargeted and Targeted Fingerprinting by Comprehensive Two-Dimensional Gas Chromatography to Track Compositional Changes on Hazelnut Primary Metabolome during Roasting

This study focuses on the detectable metabolome of high-quality raw hazelnuts (Cory- lus avellana L.) and on its changes after dry-roasting. Informative fingerprinting was obtained by comprehensive two-dimensional gas chromatography with fast-scanning quadrupole mass spectrom- etry (GC×GC-qMS) combined with dedicated data processing. In particular, combined untargeted and targeted (UT) fingerprinting, based on pattern recognition by template matching, is applied to chromatograms from raw and roasted samples of Tonda Gentile Trilobata and Anakliuri hazelnuts harvested in Italy and Georgia. Lab-scale roasting was designed to develop a desirable organoleptic profile matching industrial standards. Results, based on 430 peak features, reveal that phenotype expression is markedly correlated to cultivar and pedoclimatic conditions. Discriminant components between cultivars are amino acids (valine, alanine, glycine, and proline); organic acids (citric, aspartic, malic, gluconic, threonic, and 4-aminobutanoic acids); and sugars and polyols (maltose, xylulose, xylitol, turanose, mannitol, scyllo-inositol, and pinitol). Of these, alanine, glycine, and proline have a high informational role as precursors of 2-acetyl- and 2-propionylpyrroline, two key-aroma com- pounds of roasted hazelnuts. Roasting has a decisive impact on metabolite patterns—it caused a marked decrease (−90%) of alanine, proline, leucine and valine, and aspartic and pyroglutamic acid and a −50% reduction of saccharose and galactose

Management of giant-cell arteritis in Switzerland: an online national survey.

AIMS OF THE STUDY To assess current practices in diagnosing, treating, and following-up giant-cell arteritis by specialists in Switzerland and to identify the main barriers to using diagnostic tools. METHODS We performed a national survey of specialists potentially caring for patients with giant-cell arteritis. The survey was sent by email to all members of the Swiss Societies of Rheumatology and for Allergy and Immunology. A reminder was sent to nonresponders after 4 and 12 weeks. Its questions covered the following dimensions: respondents' main characteristics, diagnosis, treatment, and imaging's role during follow-up. The main study results were summarized using descriptive statistics. RESULTS Ninety-one specialists, primarily aged 46-65 years (n = 53/89; 59%), working in academic or nonacademic hospitals or private practice, and treating a median of 7.5 (interquartile range [IQR]: 3-12) patients with giant-cell arteritis per year participated in this survey. Ultrasound of temporal arteries/large vessels (n = 75/90; 83%) and positron-emission-tomography-computed tomography (n = 52/91; 57%) or magnetic resonance imaging (n = 46/90; 51%) of the aorta/extracranial arteries were the most common techniques used to diagnose giant-cell arteritis with cranial or large vessel involvement, respectively. Most participants reported a short time to obtain imaging tests or arterial biopsy. The glucocorticoid tapering scheme, glucocorticoid-sparing agent, and glucocorticoid-sparing treatment duration varied among the participants. Most physicians did not follow a predefined repeat imaging scheme for follow-up and mainly relied on structural changes (vascular thickening, stenosis, or dilatation) to drive treatment choice. CONCLUSIONS This survey indicates that imaging and temporal biopsy are rapidly accessible for diagnosing giant-cell arteritis in Switzerland but highlights heterogeneous practice in many disease management areas

Cleaning up Copy-Paste Clones with Interactive Merging

International audienceCopy-paste-modify is a form of software reuse in which developers explicitly duplicate source code. This duplicated source code, amounting to a code clone, is adapted for a new purpose. Copy-paste-modify is popular among software developers, however, empirical evidence shows that it complicates software maintenance and increases the frequency of bugs. To allow developers to use copy-paste-modify without having to worry about these concerns , we propose an approach that automatically merges similar pieces of code by creating suitable abstractions. Because different kinds of abstractions may be beneficial in different contexts, our approach offers multiple abstraction mechanisms, which were selected based on a study of popular open-source repositories. To demonstrate the feasibility of our approach, we have designed and implemented a prototype merging tool for C++ and evaluated it on a number of code clones exhibiting some variation, i.e near-miss clones, in popular Open Source packages. We observed that maintainers find our algorithmically created abstractions to be largely preferable to the existing duplicated code

Increased parahippocampal and lingual gyrification in first-episode schizophrenia

Objective: Cerebral gyrification is attributed to a large extent to genetic and intrauterine/ perinatal factors. Hence, investigating gyrification might offer important evidence for disturbed neurodevelopmental mechanisms in schizophrenia. As an extension of recent ROI analyses of gyrification in schizophrenia the present study is the first to compare on a node-by-node basis mean curvature as a sensitive parameter for the identification of local gyrification changes of the whole cortex in first-episode schizophrenia. Methods: A group of 54 patients with first-episode schizophrenia according to DSM-IV and 54 age and gender matched healthy control subjects were included. All participants underwent high-resolution T1-weighted MRI scans on a 1.5 T scanner. Mean curvature was calculated dividing the sum of the principal curvatures by two at each point of the curved surface as implemented in the Freesurfer Software package. Statistical cortical maps were created to estimate gyrification differences between groups based on a clustering approach. Results: A significantly increased gyrification was observed in first-episode schizophrenia patients relative to controls in a right parahippocampal-lingual cortex area. The cluster encompassed a surface area of 750 mm². A further analysis of cortical thickness of this cluster demonstrated concurrent significant reduced cortical thickness of this area. Conclusions: This is the first study to reveal an aberrant gyrification of the medial surface in first-episode schizophrenia. This finding is in line with substantial evidence showing medial temporal lobe abnormalities in schizophrenia. The present morphometric data provide further support for an early disruption of cortical maturation in schizophrenia