652 research outputs found
The monoid of queue actions
We investigate the monoid of transformations that are induced by sequences of
writing to and reading from a queue storage. We describe this monoid by means
of a confluent and terminating semi-Thue system and study some of its basic
algebraic properties, e.g., conjugacy. Moreover, we show that while several
properties concerning its rational subsets are undecidable, their uniform
membership problem is NL-complete. Furthermore, we present an algebraic
characterization of this monoid's recognizable subsets. Finally, we prove that
it is not Thurston-automatic
Blueprint and Evaluation Instruments for a Course on Software Engineering for Sustainability
We report on a summer school course on Software Engineering for Sustainability (SE4S). We provide a detailed blueprint of the contents taught and its evaluation with the instruments that were used
Clonal Dissemination Of Vana-type Glycopeptide-resistant Enterococcus Faecalis Between Hospitals Of Two Cities Located 100 Km Apart.
Nosocomial dissemination of glycopeptide-resistant enterococci represents a major problem in hospitals worldwide. In Brazil, the dissemination among hospitals in the city of São Paulo of polyclonal DNA profiles was previously described for vancomycin-resistant Enterococcus faecium. We describe here the dissemination of VanA phenotype E. faecalis between two hospitals located in different cities in the State of São Paulo. The index outbreak occurred in a tertiary care university hospital (HCUSP) in the city of São Paulo and three years later a cluster caused by the same strain was recognized in two patients hospitalized in a private tertiary care hospital (CMC) located 100 km away in the interior of the state. From May to July 1999, 10 strains of vancomycin-resistant E. faecalis were isolated from 10 patients hospitalized in the HCUSP. The DNA genotyping using pulsed-field gel electrophoresis (PFGE) showed that all isolates were originated from the same clone, suggesting nosocomial dissemination. From May to July 2002, three strains of vancomycin-resistant E. faecalis were isolated from two patients hospitalized in CMC and both patients were colonized by the vancomycin-resistant Enterococcus in skin lesions. All isolates from CMC and HCUSP were highly resistant to vancomycin and teicoplanin. The three strains from CMC had minimum inhibitory concentration >256 micro g/ml for vancomycin, and 64 (CMC 1 and CMC 2) and 96 micro g/ml (CMC 3) for teicoplanin, characterizing a profile of VanA resistance to glycopeptides. All strains had the presence of the transposon Tn1546 detected by PCR and were closely related when typed by PFGE. The dissemination of the E. faecalis VanA phenotype among hospitals located in different cities is of great concern because E. faecalis commonly colonizes the gastrointestinal tract of patients and healthy persons for periods varying from weeks to years, which, together with the persistence of vancomycin-resistant Enterococcus in hospital rooms after standard cleaning procedures, increases the risk of the dissemination and reservoir of the bacteria.371339-4
Sustainability Competencies and Skills in Software Engineering: An Industry Perspective
Achieving the UN Sustainable Development Goals (SDGs) demands adequate levels
of awareness and actions to address sustainability challenges. Software systems
will play an important role in moving towards these targets. Sustainability
skills are necessary to support the development of software systems and to
provide sustainable IT-supported services for citizens. While there is a
growing number of academic bodies, including sustainability education in
engineering and computer science curricula, there is not yet comprehensive
research on the competencies and skills required by IT professionals to develop
such systems. This study aims to identify the industrial sustainability needs
for education and training from software engineers' perspective. We conducted
interviews and focus groups with experts from twenty-eight organisations with
an IT division from nine countries to understand their interests, goals and
achievements related to sustainability, and the skills and competencies needed
to achieve their goals. Our findings show that organisations are interested in
sustainability, both idealistically and increasingly for core business reasons.
They seek to improve the sustainability of processes and products but encounter
difficulties, like the trade-off between short-term financial profitability and
long-term sustainability goals. To fill the gaps, they have promoted in-house
training courses, collaborated with universities, and sent employees to
external training. The acquired competencies make sustainability an integral
part of software development. We conclude that educational programs should
include knowledge and skills on core sustainability concepts, system thinking,
soft skills, technical sustainability, sustainability impact and measurements,
values and ethics, standards and legal aspects, and advocacy and lobbying
The unstructured linker arms of MutL enable GATC site incision beyond roadblocks during initiation of DNA mismatch repair
DNA mismatch repair (MMR) maintains genome stability through repair of DNA replication errors. In Escherichia coli, initiation of MMR involves recognition of the mismatch by MutS, recruitment of MutL, activation of endonuclease MutH and DNA strand incision at a hemimethylated GATC site. Here, we studied the mechanism of communication that couples mismatch recognition to daughter strand incision. We investigated the effect of catalytically-deficient Cas9 as well as stalled RNA polymerase as roadblocks placed on DNA in between the mismatch and GATC site in ensemble and single molecule nanomanipulation incision assays. The MMR proteins were observed to incise GATC sites beyond a roadblock, albeit with reduced efficiency. This residual incision is completely abolished upon shortening the disordered linker regions of MutL. These results indicate that roadblock bypass can be fully attributed to the long, disordered linker regions in MutL and establish that communication during MMR initiation occurs along the DNA backbone
Echinoderms have bilateral tendencies
Echinoderms take many forms of symmetry. Pentameral symmetry is the major
form and the other forms are derived from it. However, the ancestors of
echinoderms, which originated from Cambrian period, were believed to be
bilaterians. Echinoderm larvae are bilateral during their early development.
During embryonic development of starfish and sea urchins, the position and the
developmental sequence of each arm are fixed, implying an auxological
anterior/posterior axis. Starfish also possess the Hox gene cluster, which
controls symmetrical development. Overall, echinoderms are thought to have a
bilateral developmental mechanism and process. In this article, we focused on
adult starfish behaviors to corroborate its bilateral tendency. We weighed
their central disk and each arm to measure the position of the center of
gravity. We then studied their turning-over behavior, crawling behavior and
fleeing behavior statistically to obtain the center of frequency of each
behavior. By joining the center of gravity and each center of frequency, we
obtained three behavioral symmetric planes. These behavioral bilateral
tendencies might be related to the A/P axis during the embryonic development of
the starfish. It is very likely that the adult starfish is, to some extent,
bilaterian because it displays some bilateral propensity and has a definite
behavioral symmetric plane. The remainder of bilateral symmetry may have
benefited echinoderms during their evolution from the Cambrian period to the
present
Gene Regulatory Network Interactions in Sea Urchin Endomesoderm Induction
A major goal of contemporary studies of embryonic development is to understand large sets of regulatory changes that accompany the phenomenon of embryonic induction. The highly resolved sea urchin pregastrular endomesoderm–gene regulatory network (EM-GRN) provides a unique framework to study the global regulatory interactions underlying endomesoderm induction. Vegetal micromeres of the sea urchin embryo constitute a classic endomesoderm signaling center, whose potential to induce archenteron formation from presumptive ectoderm was demonstrated almost a century ago. In this work, we ectopically activate the primary mesenchyme cell–GRN (PMC-GRN) that operates in micromere progeny by misexpressing the micromere determinant Pmar1 and identify the responding EM-GRN that is induced in animal blastomeres. Using localized loss-of -function analyses in conjunction with expression of endo16, the molecular definition of micromere-dependent endomesoderm specification, we show that the TGFβ cytokine, ActivinB, is an essential component of this induction in blastomeres that emit this signal, as well as in cells that respond to it. We report that normal pregastrular endomesoderm specification requires activation of the Pmar1-inducible subset of the EM-GRN by the same cytokine, strongly suggesting that early micromere-mediated endomesoderm specification, which regulates timely gastrulation in the sea urchin embryo, is also ActivinB dependent. This study unexpectedly uncovers the existence of an additional uncharacterized micromere signal to endomesoderm progenitors, significantly revising existing models. In one of the first network-level characterizations of an intercellular inductive phenomenon, we describe an important in vivo model of the requirement of ActivinB signaling in the earliest steps of embryonic endomesoderm progenitor specification
Aplicação de patterns no desenvolvimento de um sistema CAD para microeletrônica
Apresenta a aplicação de técnica de orientação a objetos para resolver problemas de integração em ferramentas de CAD para microeletrônica. A abordagem enfatiza o uso de patterns e componentização para obter homogeneidade e o reuso de software. Os componentes são responsáveis por realizar tarefas básicas como a interpretação de linguagens e edição gráfica. A divisão de arquitetura em camadas garante a modularidade e provê o acoplamento de ferramentas funcionais. A arquitetura também suporta a distribuição de objetos, aumentando o potencial de processamento em redes de computadores
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