The Impact of Code Review on Architectural Changes

Although considered one of the most important decisions in the software development lifecycle, empirical evidence on how developers perform and perceive architectural changes remains scarce. Architectural decisions have far-reaching consequences yet, we know relatively little about the level of developers' awareness of their changes' impact on the software's architecture. We also know little about whether architecture-related discussions between developers lead to better architectural changes. To provide a better understanding of these questions, we use the code review data from 7 open source systems to investigate developers' intent and awareness when performing changes alongside the evolution of the changes during the reviewing process. We extracted the code base of 18,400 reviews and 51,889 revisions. 4,171 of the reviews have changes in their computed architectural metrics, and 731 present significant changes to the architecture. We manually inspected all reviews that caused significant changes and found that developers are discussing the impact of their changes on the architectural structure in only 31% of the cases, suggesting a lack of awareness. Moreover, we noticed that in 73% of the cases in which developers provided architectural feedback during code review, the comments were addressed, where the final merged revision tended to exhibit higher architectural improvement than reviews in which the system's structure is not discussed

CROP: linking code reviews to source code changes

Code review has been widely adopted by both industrial and open source software development communities. Research in code review is highly dependant on real-world data, and although existing researchers have attempted to provide code review datasets, there is still no dataset that links code reviews with complete versions of the system's code base mainly because reviewed versions are not kept in the system's version control repository. Thus, we present CROP, the Code Review Open Platform, the first curated code review repository that links review data with isolated complete versions (snapshots) of the source code at the time of review. CROP currently provides data for 8 software systems, 48,975 reviews and 112,617 patches, including versions of the systems that are inaccessible in the systems' original repositories. Moreover, CROP is extensible, and it will be continuously curated and extended

Análise espacial do período chuvoso em Minas Gerais.

Este trabalho analisa os dados provenientes de séries pluviométricas de 430 estações no Estado de Minas Gerais, Brasil. Das estações analisadas, 192 tiveram períodos compreendidos entre 30 e 65 anos de medições e o restante com mais de 50 anos. Após proceder à análise de consistência dos dados, foram elaborados mapas de precipitação média anual, mapas do início do período chuvoso, término e duração. Os resultados mostram que as áreas de menores índices pluviométricos são as de maior risco de déficit hídrico, isto é, possuem má distribuição das precipitações ao longo do ano. As regiões de maiores incidências de chuvas de alta intensidade são o Triângulo Mineiro, Região Metropolitana de Belo Horizonte, Vale do Rio Doce e Zona da Mata. Dentre essas, apenas a região do Triângulo Mineiro não apresenta relevo acidentado. O período chuvoso em Minas Gerais começa nas regiões oeste, sul e Triângulo (primeira e segunda semana de outubro). O período chuvoso na região nordeste começa somente na segunda semana de novembro e o término acontece nas duas primeiras semanas de março. O trabalho é de grande importância para a agricultura de Minas Gerais, oferecendo subsídios para os agricultores, agentes financeiros e investidores

Are developers aware of the architectural impact of their changes?

Although considered one of the most important decisions in a software development lifecycle, empirical evidence on how developers perform and perceive architectural changes is still scarce. Given the large implications of architectural decisions, we do not know whether developers are aware of their changes' impact on the software's architecture, whether awareness leads to better changes, and whether automatically making developers aware would prevent degradation. Therefore, we use code review data of 4 open source systems to investigate the intent and awareness of developers when performing changes. We extracted 8,900 reviews for which the commits are available. 2,152 of the commits have changes in their computed architectural metrics, and 338 present significant changes to the architecture. We manually inspected all reviews for commits with significant changes and found that only in 38% of the time developers are discussing the impact of their changes on the architectural structure, suggesting a lack of awareness. Finally, we observed that developers tend to be more aware of the architectural impact of their changes when the architectural structure is improved, suggesting that developers should be automatically made aware when their changes degrade the architectural structure

Determinação das áreas de potencial de riscos de precipitações intensas em Belo Horizonte.

A áreas urbanas têm sido objeto de estudos climatológicos por causa da formação de "ilhas de calor", entretanto, as chuvas intensas são as responsáveis por causar os principais desastres. Eventos extremos de precipitações têm aumentado significativamente nas últimas duas décadas no município de Belo Horizonte, ocasionando enchentes urbanas, desabamentos de casas e desmoronamentos. A instalação de uma rede de pluviômetros para a coleta de dados durante a estação chuvosa 2003/04 na região metropolitana, permitiu a análise espacial das precipitações, regionalização dos dados, elaboração de um mapa de regiões com alto potencial de chuvas intensas e a elaboração de alertas diários de tempestades severas

Mn substitution-modified polar phase in the Bi1-xNdxFeO3 multiferroics

Room-temperature crystal structure and multiferroic properties of the Bi0.92Nd0.08Fe1-xMnxO3 (x <= 0.3) ferromanganites have been studied to reveal the effect of Mn doping on the magnetic and ferroelectric behaviors of the lanthanide-modified compound representing a polar (space group R3c) predominantly antiferromagnetic phase of the Bi(1-x)Ln(x)FeO(3) perovskites. B-site substitution tends to suppress existing polar displacements and induces a ferroelectric-to-antiferroelectric transition near x = 0.2. The threshold concentration inducing the structural transformation does not coincide with that required to change the dominant magnetic interaction, so a weak ferromagnetic/ferroelectric state unusual for the Bi(1-x)Ln(x)FeO(3) and BiFe1-xMnxO3 series appears in the intermediate concentration range near the polar/nonpolar phase boundary. (C) 2013 AIP Publishing LLC

Staphylococcus saprophyticus from clinical and environmental origins have distinct biofilm composition

Biofilm formation has been shown to be critical to the success of uropathogens. Although Staphylococcus saprophyticus is a common cause of urinary tract infections, its biofilm production capacity, composition, genetic basis, and origin are poorly understood. We investigated biofilm formation in a large and diverse collection of S. saprophyticus (n = 422). Biofilm matrix composition was assessed in representative strains (n = 63) belonging to two main S. saprophyticus lineages (G and S) recovered from human infection, colonization, and food-related environment using biofilm detachment approach. To identify factors that could be associated with biofilm formation and structure variation, we used a pangenome-wide association study approach. Almost all the isolates (91%; n = 384/422) produced biofilm. Among the 63 representative strains, we identified eight biofilm matrix phenotypes, but the most common were composed of protein or protein-extracellular DNA (eDNA)-polysaccharides (38%, 24/63 each). Biofilms containing protein-eDNA-polysaccharides were linked to lineage G and environmental isolates, whereas protein-based biofilms were produced by lineage S and infection isolates (p < 0.05). Putative biofilm-associated genes, namely, aas, atl, ebpS, uafA, sasF, sasD, sdrH, splE, sdrE, sdrC, sraP, and ica genes, were found with different frequencies (3-100%), but there was no correlation between their presence and biofilm production or matrix types. Notably, icaC_1 was ubiquitous in the collection, while icaR was lineage G-associated, and only four strains carried a complete ica gene cluster (icaADBCR) except one that was without icaR. We provided evidence, using a comparative genomic approach, that the complete icaADBCR cluster was acquired multiple times by S. saprophyticus and originated from other coagulase-negative staphylococci. Overall, the composition of S. saprophyticus biofilms was distinct in environmental and clinical isolates, suggesting that modulation of biofilm structure could be a key step in the pathogenicity of these bacteria. Moreover, biofilm production in S. saprophyticus is ica-independent, and the complete icaADBCR was acquired from other staphylococci