Preventing Atomicity Violations with Contracts

Software developers are expected to protect concurrent accesses to shared regions of memory with some mutual exclusion primitive that ensures atomicity properties to a sequence of program statements. This approach prevents data races but may fail to provide all necessary correctness properties.The composition of correlated atomic operations without further synchronization may cause atomicity violations. Atomic violations may be avoided by grouping the correlated atomic regions in a single larger atomic scope. Concurrent programs are particularly prone to atomicity violations when they use services provided by third party packages or modules, since the programmer may fail to identify which services are correlated. In this paper we propose to use contracts for concurrency, where the developer of a module writes a set of contract terms that specify which methods are correlated and must be executed in the same atomic scope. These contracts are then used to verify the correctness of the main program with respect to the usage of the module(s). If a contract is well defined and complete, and the main program respects it, then the program is safe from atomicity violations with respect to that module. We also propose a static analysis based methodology to verify contracts for concurrency that we applied to some real-world software packages. The bug we found in Tomcat 6.0 was immediately acknowledged and corrected by its development team

Influence of Prior Exercise on VO2 Kinetics Subsequent Exhaustive Rowing Performance

Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercisetime during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderateexercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longerexercise time at VO2max. Six subjects (mean 6 SD; age: 22.964.5 yr; height: 181.267.1 cm and body mass: 75.563.4 kg)completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with priormoderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b2, Cosmed, Rome, Italy) andthe data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in afaster VO2 pulmonary kinetics response (t1 = 13.4163.96 s), an improved performance in the time to xhaustion(238.8650.2 s) and similar blood lactate concentrations ([La2]) values (11.861.7 mmol.L21) compared to the onditionwithout prior exercise (16.065.56 s, 215.3660.1 s and 10.761.2 mmol.L21, for t1, time sustained at VO2max and [La2], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics responseduring a subsequent time to exhaustion exercise (t1 = 9.1861.60 s), resulted in a shorter time sustained at VO2max(155.5646.0 s), while [La2] was similar (13.561.7 mmol.L21) compared to the other two conditions. Although both priormoderate and heavy exercise ulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance.info:eu-repo/semantics/publishedVersio

Traction system for electric vehicles based on synchronous reluctance permanent magnet machine

Electric vehicles (EVs) integrate two main power electronics systems, namely, the battery charging system and the traction system. In this study, we aimed to complement and deepen the study of the latter, more specifically, focusing on a traction system based on a synchronous reluctance permanent magnet (SRPM) machine, since this is an emerging electric machine in the EV paradigm. The developed prototype integrates bidirectional ac-dc and dc-dc converters, allowing for regenerative braking, and the SRPM machine is controlled using a maximum torque per ampere (MTPA) algorithm. Computer simulations and the experimental results for the traction system are presented in this paper. The dynamic characteristics of the SRPM machine proved to be relevant for EV applications, with effective results obtained during load and speed changes. The effective behavior of the SRPM machine was partially rooted in the use of the MTPA algorithm, which has proven itself to be an effective algorithm for the electric machines of EVs.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Water distribution network reliability: are surrogate measures reliable?

Water distribution networks are known to be costly infrastructures. A few decades ago the research efforts concerning water distribution network design were focused on economic aspects and the goal was to obtain least cost solutions. Beyond economic, these infrastructures must be reliable since they provide an essential service to society. Reliability assessment is a complex task and involves various aspects: mechanical, hydraulic, water quality, water safety, among others. This paper focus is on the hydraulic reliability. As hydraulic reliability is computationally hard to measure directly, researchers came up with surrogate measures, like the resilience index or the flow entropy. But these surrogate measures had some flaws and researchers quickly started suggesting new ones trying to avoid those known flaws, like the modified resilience index or the diameter-sensitive flow entropy. But are these surrogate measures reliable to be used in the design of water distribution networks? This paper presents a thorough analysis of these reliability surrogate measures, supported by illustrative examples, highlighting their pros and cons to help in deciding which one to use for design purposes. A new reliability index is proposed and used to design an example network, its advantages are highlighted, and the above question answered.info:eu-repo/semantics/publishedVersio

Application of shearband boudins analysis to understand ductile shear zones

The methodology used for the kinematic analysis of H-T ductile shear zones based on geometric analysis of boudins, proved to be a easy application tool. The boudin analysis begans with the measurement of the Lb (boudin axis) orientation, as a fundamental element of the kinematic analysis in simple shear – Lb proved always to be perpendicular to a local displacement plane (Sx) that is defined as the plane that contains different lineations (e.g., stretching lineation in the host rock) and so, validates the orientation of the outcrop plane. The methodology also includes the measurement of several angular and dimensional parameters. The main objective of this study deals with the validation of the broad utility of this methodology in shear zones with different P-T conditions. It was studied a shearband boudin field on a Grt-St shear zone, which was compared with previous studies on Sil shear zone.Fundação para a Ciência e a Tecnologia (FCT

Characterization of ductile shear zones with different P-T conditions based on the geometric analyzes of shearband boudins

No presente trabalho analisou-se a relação entre a morfologia de corpos boudinados e as condições tectono-metamórficas em que estes se formaram e evoluíram. Com base neste pressuposto formula-se a hipótese de ser possível associar boudins, com características geométricas bem definidas, a ambientes metamórficos específicos. Foram estudados 345 boudins, distribuidos por quatro regiões com distintos graus de metamorfismo: Serra da Salgosa, Praia da Granja, Aracena e Acebuches. Relativamente a cada boudin foi analisada a relação entre os rácios de parâmetros geométricos e o ângulo θ (ângulo entre a superficie interna do boudin – Sib – e a superfície externa do boudin – Sb). Os dados obtidos permitiram concluir que a morfologia do boudin parece depender de fatores, tais como, a espessura e natureza do corpo boudinado, o contraste de viscosidade e a taxa de deformaçao, não sendo clara uma relação entre a morfologia do boudin e o ambiente metamórfico em que este se formou.In this study we pretend to analyze the relation between the boudins morphology and the tectono-metamorphic environment where they were formed and evolved. Therefore, it would be possible to associate boudins, with well-defined geometric parameters, to a specific metamorphic environment. During this study 345 boudins have been analyzed, distributed along four different areas with distinct metamorphism degrees: Serra da Salgosa, Praia da Granja, Aracena and Acebuches. For each boudin, the relation between ratios of different geometric parameters and the θ angle (angle between the boudin internal surface – Sib – and the boudin external surface – Sb) were analyzed. The obtain data allow us to conclude that the boudin morphology appears to depend on factors such as the layer thickness and nature, matrix/layer viscosity contrast and strain rate. The relation between the boudin morphology and the metamorphic environment where it was formed doesn´t seems clear.Fundação para a Ciência e a Tecnologia (FCT

Must deacidification with an induced flocculant yeast strain of Schizosaccharomyces pombe

The use of flocculant cells of the yeast strain SchizosaFcharomyces pombe for the deacidification of grape musts in continuous culture was developed. An external loop reactor was used to induce flocculation. The flocs obtained were stable in the pH range 3.0-6.0 and in the presence of several sugars. Some inhibition was observed for high (above 6.0) and low (below 3.0) pH values. Once induced, flocculation could no longer be completely inhibited. Vinho Verde, a typical Portuguese wine, has a relatively low ethanol content and a high acid concentration. The external loop reactor loaded with the flocculant cells was used to deacidify a synthetic medium with sugar and malic acid concentrations similar to the ones found in Vinho Verde grape must. A desirable malic acid decrease with moderate glucose consumption was obtained at a dilution rate of 0.7 h-1. Improved results were obtained when the synthetic medium was replaced by Vinho Verde grape must

The LSTS open-source communication and autonomy software: enabling networked vehicle systems to find track, and sample dynamic features of the ocean

Peer Reviewe

A new strategy for RNA isolation from eukaryotic cells using arginine affinity chromatography

The relevance of RNA in many biological functions has been recognized, broadening the scope of RNA research activities, from basic to applied sciences, also aiming the translation to clinical fields. The preparation and purification of RNA is a critical step for further application, since the quality of the template is crucial to ensure reproducibility and biological relevance. Therefore, the establishment of new tools that allows the isolation of pure RNA with high quality is of particular importance. New chromatographic strategies for RNA purification were considered, exploiting affinity interactions between amino acids and nucleic acids. In the present study, a single arginine-affinity chromatography step was employed for the purification of RNA from a total eukaryotic nucleic acid extract, thus eliminating several steps compared with current RNA isolation procedures. The application of this process resulted in a high RNA recovery yield of 96 ± 17% and the quality control analysis revealed a high integrity (28S:18S ratio = 1.96) in RNA preparations as well as a good purity, demonstrated by the scarce detection of proteins and the reduction on genomic DNA contamination to residual concentrations. Furthermore, the performance of the new RNA isolation method was tested regarding the applicability of the isolated RNA in modern molecular biology techniques. Hence, this new affinity approach will simplify the isolation and purification of RNA, which can bring great improvements in biomedical investigation.info:eu-repo/semantics/publishedVersio