Synthesizing Certified Code

Code certification is a lightweight approach for formally demonstrating software quality. Its basic idea is to require code producers to provide formal proofs that their code satisfies certain quality properties. These proofs serve as certificates that can be checked independently. Since code certification uses the same underlying technology as program verification, it requires detailed annotations (e.g., loop invariants) to make the proofs possible. However, manually adding annotations to the code is time-consuming and error-prone. We address this problem by combining code certification with automatic program synthesis. Given a high-level specification, our approach simultaneously generates code and all annotations required to certify the generated code. We describe a certification extension of AutoBayes, a synthesis tool for automatically generating data analysis programs. Based on built-in domain knowledge, proof annotations are added and used to generate proof obligations that are discharged by the automated theorem prover E-SETHEO. We demonstrate our approach by certifying operator- and memory-safety on a data-classification program. For this program, our approach was faster and more precise than PolySpace, a commercial static analysis tool

Seismicity from february 2006 to september 2007 at the Rwenzori Mountains, East African Rift: earthquake distribution, magnitudes and source mechanisms

We have analysed the microseismic activity within the Rwenzori Mountains area in the western branch of the East African Rift. Seismogram recordings from a temporary array of up to 27 stations reveal approximately 800 events per month with local magnitudes ranging from –0.5 to 5.1. The earthquake distribution is highly heterogeneous. The majority of located events lie within faults zones to the east and west of the Rwenzoris with the highest seismic activity observed in the northeastern area, where the mountains are in contact with the rift shoulders. The hypocentral depth distribution exhibits a pronounced peak of seismic energy release at 15 km depth. The maximum extent of seismicity ranges from 20 to 32 km and correlates well with Moho depths that were derived from teleseismic receiver functions. We observe two general features: (i) beneath the rift shoulders, seismicity extends from the surface down to ca. 30 km depth; (ii) beneath the rift valley, seismicity is confined to depths greater than 10 km. From the observations there is no indication for a crustal root beneath the Rwenzori Mountains. The magnitude frequency distribution reveals a b-value of 1.1, which is consistent with the hypothesis that part of the seismicity is caused by magmatic processes within the crust. Fault plane solutions of 304 events were derived from P-polarities and SV/P amplitude ratios. More than 70 % of the source mechanisms exhibit pure or predominantly normal faulting. T-axis trends are highly uniform and oriented WNW–ESE, which is perpendicular to the rift axis and in good agreement with kinematic rift models. At the northernmost part of the region we observe a rotation of the T-axis trends to NEN–SWS, which may be indicative of a local perturbation of the regional stress field

Seismicity at the Rwenzori Mountains, East African Rift: earthquake distribution, magnitudes and source mechanisms

We have analysed the microseismic activity within the Rwenzori Mountains area in the western branch of the East African Rift. Seismogram recordings from a temporary array of up to 27 stations reveal approximately 800 events per month with local magnitudes ranging from –0.5 to 5.1. The earthquake distribution is highly heterogeneous. The majority of located events lie within faults zones to the East and West of the Rwenzoris with the highest seismic activity observed in the northeastern area, where the mountains are in contact with the rift shoulders. The hypocentral depth distribution exhibits a pronounced peak of seismic energy release at 15 km depth. The maximum extent of seismicity ranges from 20 to 32 km and correlates well with Moho depths that were derived from teleseismic receiver functions. We observe two general features: (i) beneath the rift shoulders seismicity extends from the surface down to ca. 30 km depth; (ii) beneath the rift valley seismicity is confined to depths greater than 10 km. From the observations there is no indication for a crustal root beneath the Rwenzori Mountains. The magnitude frequency distribution reveals a b-value of 1.1, which is consistent with the hypothesis that part of the seismicity is caused by magmatic processes within the crust. Fault plane solutions of 304 events were derived from P-polarities and SV/P amplitude ratios. More than 70 % of the source mechanisms exhibit pure or predominantly normal faulting. T-axis trends are highly uniform and oriented WNW-ESE, which is perpendicular to the rift axis and in good agreement with kinematic rift models. At the northernmost part of the region we observe a rotation of the T-axis trends to NEN-SWS, which may be indicative of a local perturbation of the regional stress field

Unlucky to Be Young? The Long-Term Effects of School Starting Age on Smoking Behaviour and Health

In this study, we analyse the long-term effects of school starting age on smoking behaviour and health in adulthood. School entry rules combined with birth month are used as an instrument for school starting age. The analysis adopts the German Socio- Economic Panel data and employs a fuzzy regression discontinuity design. The results reveal that school starting age reduces the long-term risk to smoke, improves long-term health, and affects physical rather than mental health. In addition, we find that the relative age composition of peers and the school environment are important mechanisms

Design of a Reference Architecture for Production Scheduling Applications based on a Problem Representation including Practical Constraints

Changing customer demands increase the complexity and importance of production scheduling, requiring better scheduling algorithms, e.g., machine learning algorithms. At the same time, current research often neglects practical constraints, e.g., changeovers or transportation. To address this issue, we derive a representation of the scheduling problem and develop a reference architecture for future scheduling applications to increase the impact of future research. To achieve this goal, we apply a design science research approach and, first, rigorously identify the problem and derive requirements for a scheduling application based on a structured literature review. Then, we develop the problem representation and reference architecture as design science artifacts. Finally, we demonstrate the artifacts in an application scenario and publish the resulting prototypical scheduling application, enabling machine learning-based scheduling algorithms, for usage in future development projects. Our results guide future research into including practical constraints and provide practitioners with a framework for developing scheduling applications

Can We Compare Attitudes Towards Crime Around the World? Assessing Measurement Invariance of the Morally Debatable Behavior Scale Across 44 Countries

Objectives: We aim to encourage scholars who conduct cross-national criminological studies to routinely assess measurement invariance (MI), that is, verify if multi-item instruments that capture latent constructs are conceptualized and understood similarily across different populations. To promote the adoption of MI tests, we present an analytical protocol, including an annotated R script and output file. We implement the protocol and, doing so, document the first test of configural, metric, and scalar invariance of the three-factor Morally Debatable Behavior Scale (MDBS). // Methods: We worked with data from wave seven of the World Values Survey (WVS). Applying multi-group confirmatory factor analyses, we, first, explored invariance of the MDBS in 44 countries (N = 59,482). Next, we conducted analyses separately for seven South-american, six South-east Asian, six East-asian, two North American and Australasian, and all four Anglophone countries. // Results: The MDBS displays an overall lack of invariance. However, we confirmed configural invariance of the MDBS for the South-east Asian sample, metric invariance in the sample of Anglophone countries, and scalar invariance for the Australasian and North American countries. // Conclusions: Wave seven of the WVS can be used for latent mean score comparisons of the MDBS between the Australasian and North American countries. Associative relationships can be compared in the larger Anglophone sub-sample. Taken together, MI must be tested, and cannot be assumed, even when analyzing data from countries for which previous research has established cultural similarities. Our protocol and practical recommendations guide researchers in this process

Metallorganische Verbindungen der Lanthanoiden, XTTT [1] Tris(di-f-butylarsin)-Derivate von Yttrium, Lanthan, Praseodym, Holmium, Erbium, Thulium und Lutetium

Lithium (di-t-butyl) arsenide reacts with the trichlorides of yttrium, lanthanum, praseodymium, holmium, erbium, thulium, and lutetium under elimination of lithium chloride and formation of the corresponding tris(di-t-butylarsine) derivatives

Synthese und Eigenschaften einiger neuer Organoindium-Methylenstannyl-Verbindungen

Im Zusammenhang mit unseren Arbeiten zur Herstellung leitfähiger Schichten für Flüssigkristall-Displays konnten wir kürzlich über die erstmalige Synthese metallorganischer Verbindungen berichten, die sowohl Zinn als auch Indium in einem Molekül enthalten, wie z.B. Me3SnCH2InMe2 [1]

Intestinal Barrier Function in Gluten-Related Disorders

Gluten-related disorders include distinct disease entities, namely celiac disease, wheat-associated allergy and non-celiac gluten/wheat sensitivity. Despite having in common the contact of the gastrointestinal mucosa with components of wheat and other cereals as a causative factor, these clinical entities have distinct pathophysiological pathways. In celiac disease, a T-cell mediate immune reaction triggered by gluten ingestion is central in the pathogenesis of the enteropathy, while wheat allergy develops as a rapid immunoglobulin E- or non-immunoglobulin E-mediated immune response. In non-celiac wheat sensitivity, classical adaptive immune responses are not involved. Instead, recent research has revealed that an innate immune response to a yet-to-be-defined antigen, as well as the gut microbiota, are pivotal in the development in this disorder. Although impairment of the epithelial barrier has been described in all three clinical conditions, its role as a potential pathogenetic co-factor, specifically in celiac disease and non-celiac wheat sensitivity, is still a matter of investigation. This article gives a short overview of the mucosal barrier of the small intestine, summarizes the aspects of barrier dysfunction observed in all three gluten-related disorders and reviews literature data in favor of a primary involvement of the epithelial barrier in the development of celiac disease and non-celiac wheat sensitivity