Software engineering is an intensely people-oriented activity, yet too little is known about how designers, maintainers, requirements analysts and all other types of software engineers perform their work. In order to improve software engineering tools and practice, it is therefore essential to conduct field studies, i.e., to study real practitioners as they solve real problems. To do so effectively, however, requires an understanding of the techniques most suited to each type of field study task. In this paper, we provide a taxonomy of techniques, focusing on those for data collection. The taxonomy is organized according to the degree of human intervention each requires. For each technique, we provide examples from the literature, an analysis of some of its advantages and disadvantages, and a discussion of how to use it effectively. We also briefly talk about field study design in general, and data analysis.

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Highlights d scRNA sequencing reveals two distinct aortic endothelial populations d Sequencing analysis confirms transitionary cells rather than discrete populations d Endovascular progenitors are slow cycling and have distinct mitochondrial content

Software developers search the Web for various kinds of source code for diverse reasons. In a previous study, we found that searches varied along two dimensions: the size of the search target (e.g., block, subsystem, or system) and the motivation for the search (e.g., reference example or as-is reuse). Would each of these kinds of searches require different search technologies? To answer this question, we conducted an experiment with 36 participants to evaluate three diverse approaches (general purpose information retrieval, source code search, and component reuse), as represented by five Web sites (Google, Koders, Krugle, Google Code Search, and SourceForge). The independent variables were search engine, size of search target, and motivation for search. The dependent variable was the participants judgement of the relevance of the first ten hits. We found that it was easier to find reference examples than components for as-is reuse and that participants obtained the best results using a general-purpose information retrieval site. However, we also found an interaction effect: code-specific search engines worked better in searches for subsystems, but Google worked better on searches for blocks. These results can be used to guide the creation of new tools for retrieving source code from the Web.

The ability of bone for regeneration has long been recognized. However, once beyond a critical size, spontaneous regeneration of bone is limited. Several studies have focused on enhancing bone regeneration by applying mesenchymal stromal/stem cells (MSCs) in the treatment strategies. Despite the therapeutic efficacy of MSCs in bone regeneration, cell-based therapies are impeded by several challenges in maintaining the optimal cell potency and viability during expansion, storage, and final delivery to patients. Recently, there has been a paradigm shift in therapeutic mechanism of MSCs in tissue repair from one based on cellular differentiation and replacement to one based on secretion and paracrine signaling. Among the broad spectrum of trophic factors, extracellular vesicles ​particularly the exosomes have been reported to be therapeutically efficacious in several injury/disease indications, including bone defects and diseases. The current systematic review aims to summarize the results of the existing animal studies which were conducted to evaluate the therapeutic efficacy of MSC exosomes for bone regeneration. Following the Preferred Reporting Items for Systematic Reviews and Meta-analysis ​guidelines, the PubMed and The Cochrane Library database were searched for relevant controlled preclinical animal studies. A total of 23 studies were identified, with the total sample size being 690 rats or mice and 38 rabbits. Generally, MSC exosomes were found to be efficacious for bone regeneration in animal models of bone defects and diseases such as osteonecrosis and osteoporosis. In these studies, MSC exosomes promoted new bone formation with supporting vasculature ​and displayed improved morphological, biomechanical, and histological outcomes, coupled with positive effects on cell survival, proliferation, and migration, osteogenesis, and angiogenesis. Unclear-to-low risk in bias and incomplete reporting in the primary studies highlighted the need for standardization in outcome measurements and reporting. Further studies in large animal models to establish the safety and efficacy would provide useful information on guiding the design of clinical trials.

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Joining a software development team is like moving to a new country to start employment; the immigrant has a lot to learn about the job, the local customs, and sometimes a new language.In an exploratory case study, we interviewed four software immigrants, in order to characterize their naturalization process. Seven patterns in four major categories were found. In this paper, these patterns are substantiated, and their implications discussed. The lessons learned from this study can be applied equally to improving the naturalization process, and to the formulation of further research questions.

Tumor vascularization is a hallmark of cancer central to disease progression and metastasis. Current anti-angiogenic therapies have limited success prompting the need to better understand the cellular origin of tumor vessels. Using fate-mapping analysis of endothelial cell populations in melanoma, we report the very early infiltration of endovascular progenitors (EVP) in growing tumors. These cells harbored self-renewal and reactivated the expression of SOX18 transcription factor, initiating a vasculogenic process as single cells, progressing towards a transit amplifying stage and ultimately differentiating into more mature endothelial phenotypes that comprised arterial, venous and lymphatic subtypes within the core of the tumor. Molecular profiling by RNA sequencing of purified endothelial fractions characterized EVPs as quiescent progenitors remodeling the extracellular matrix with significant paracrine activity promoting growth. Functionally, EVPs did not rely on VEGF-A signaling whereas endothelial-specific loss of Rbpj depleted the population and strongly inhibited metastasis. The understanding of endothelial heterogeneity opens new avenues for more effective anti-vascular therapies in cancer.