Commercial participation continues to grow in open source software (OSS) projects and novel arrangements appear to emerge in company-dominated projects and ecosystems. What is the nature of these ...novel arrangements? Does volunteers' participation remain critical for these ecosystems? Despite extensive research on commercial participation in OSS, the exact nature and extent of company contributions to OSS development, and the impact of this engagement may have on the volunteer community have not been clarified. To bridge the gap, we perform an exploratory study of OpenStack: a large OSS ecosystem with intense commercial participation. We quantify companies' contributions via the developers that they provide and the commits made by those developers. We find that companies made far more contributions than volunteers and the distribution of the contributions made by different companies is also highly unbalanced. We observe eight unique contribution models based on companies' commercial objectives and characterize each model according to three dimensions: contribution intensity, extent, and focus. Companies providing full cloud solutions tend to make both intensive (more than other companies) and extensive (involving a wider variety of projects) contributions. Usage-oriented companies make extensive but less intense contributions. Companies driven by particular business needs focus their contributions on the specific projects addressing these needs. Minor contributors include community players (e.g., the Linux Foundation) and research groups. A model relating the number of volunteers to the diversity of contribution shows a strong positive association between them.
Motivation: To survive and succeed, FLOSS projects need contributors able to accomplish critical project tasks. However, such tasks require extensive project experience of long term contributors ...(LTCs). Aim: We measure, understand, and predict how the newcomers' involvement and environment in the issue tracking system (ITS) affect their odds of becoming an LTC. Method: ITS data of Mozilla and Gnome, literature, interviews, and online documents were used to design measures of involvement and environment. A logistic regression model was used to explain and predict contributor's odds of becoming an LTC. We also reproduced the results on new data provided by Mozilla. Results: We constructed nine measures of involvement and environment based on events recorded in an ITS. Macro-climate is the overall project environment while micro-climate is person-specific and varies among the participants. Newcomers who are able to get at least one issue reported in the first month to be fixed, doubled their odds of becoming an LTC. The macro-climate with high project popularity and the micro-climate with low attention from peers reduced the odds. The precision of LTC prediction was 38 times higher than for a random predictor. We were able to reproduce the results with new Mozilla data without losing the significance or predictive power of the previously published model. We encountered unexpected changes in some attributes and suggest ways to make analysis of ITS data more reproducible. Conclusions: The findings suggest the importance of initial behaviors and experiences of new participants and outline empirically-based approaches to help the communities with the recruitment of contributors for long-term participation and to help the participants contribute more effectively. To facilitate the reproduction of the study and of the proposed measures in other contexts, we provide the data we retrieved and the scripts we wrote at https://www.passion-lab.org/projects/developerfluency.html.
The metalloradical activation of o‐aryl aldehydes with tosylhydrazide and a cobalt(II) porphyrin catalyst produces cobalt(III)‐carbene radical intermediates, providing a new and powerful strategy for ...the synthesis of medium‐sized ring structures. Herein we make use of the intrinsic radical‐type reactivity of cobalt(III)‐carbene radical intermediates in the CoII(TPP)‐catalyzed (TPP=tetraphenylporphyrin) synthesis of two types of 8‐membered ring compounds; novel dibenzocyclooctenes and unprecedented monobenzocyclooctadienes. The method was successfully applied to afford a variety of 8‐membered ring compounds in good yields and with excellent substituent tolerance. Density functional theory (DFT) calculations and experimental results suggest that the reactions proceed via hydrogen atom transfer from the bis‐allylic/benzallylic C−H bond to the carbene radical, followed by two divergent processes for ring‐closure to the two different types of 8‐membered ring products. While the dibenzocyclooctenes are most likely formed by dissociation of o‐quinodimethanes (o‐QDMs) which undergo a non‐catalyzed 8π‐cyclization, DFT calculations suggest that ring‐closure to the monobenzocyclooctadienes involves a radical‐rebound step in the coordination sphere of cobalt. The latter mechanism implies that unprecedented enantioselective ring‐closure reactions to chiral monobenzocyclooctadienes should be possible, as was confirmed for reactions mediated by a chiral cobalt‐porphyrin catalyst.
Back in the ring! An efficient strategy based on metalloradical catalysis leads to 8‐membered ring compounds. Both dibenzocyclooctenes and monobenzocyclooctadienes can be obtained in high yields under mild reaction conditions. DFT calculations indicate different ring‐closure pathways for the formation of these two structures.
Hamartoma of the breast: A rare case report Chi, Yongxing; Chen, Jia; Zhou, Minghui ...
Asian journal of surgery,
April 2024, 2024-Apr, 2024-04-00, 2024-04-01, Letnik:
47, Številka:
4
Journal Article
Paeonia ostii
, a widely cultivated tree peony species in China, is a resourceful plant with medicinal, ornamental and oil value. However, fleshy roots lead to a low tolerance to waterlogging in
P. ...ostii
. In this study,
P. ostii
roots were sequenced using a hybrid approach combining single-molecule real-time and next-generation sequencing platforms to understand the molecular mechanism underlying the response to this sequentially waterlogging stress, the normal growth, waterlogging treatment (WT), and waterlogging recovery treatment (WRT). Our results indicated that the strategy of
P. ostii
, in response to WT, was a hypoxic resting syndrome, wherein the glycolysis and fermentation processes were accelerated to maintain energy levels and the tricarboxylic acid cycle was inhibited.
P. ostii
enhanced waterlogging tolerance by reducing the uptake of nitrate and water from the soil. Moreover, transcription factors, such as AP2/EREBP, WRKY, MYB, and NAC, played essential roles in response to WT and WRT. They were all induced in response to the WT condition, while the decreasing expression levels were observed under the WRT condition. Our results contribute to understanding the defense mechanisms against waterlogging stress in
P. ostii
.
To survive and succeed, software projects need to attract and retain contributors. We model the individual's chances to become a valuable contributor through her capacity, willingness, and the ...opportunity to contribute at the time of joining. Using issue tracking data of Mozilla and Gnome, we find that the probability for a new joiner to become a Long Term Contributor (LTC) is associated with her willingness and environment. Specifically, during their first month, future LTCs tend to be more active and show more community-oriented attitude than other joiners. Joiners who start by commenting on instead of reporting an issue or ones who succeed to get at least one reported issue to be fixed, more than double their odds of becoming an LTC. The micro-climate with a productive and clustered peer group increases the odds. On the contrary, the macro-climate with high project popularity and the micro-climate with low attention from peers reduce the odds. This implies that the interaction between individual's attitude and project's climate are associated with the odds that an individual would become a valuable contributor or disengage from the project. Our findings may provide a basis for empirical approaches to design a better community architecture and to improve the experience of contributors.
A simple, rapid, sensitive, accurate, and automatic graphite furnace atomic absorption spectrometry (GFAAS) method for detecting Cd and Pb in cereals is presented. This method enables the ...simultaneous determination of Cd and Pb in cereals with a pre-treatment method of diluted acid extraction and a high-performance lead-cadmium composite hollow-cathode lamp (LCC-HCL), and it realizes automatic determination from sample weighing to result output through an automatic diluted acid extraction system. Under the optimization, Pb and Cd in cereals were simultaneously and automatically detected in up to 240 measurements in 8 h. The LOD and LOQ of this method were 0.012 and 0.040 mg·kg
for Pb, and 0.0014 and 0.0047 mg·kg
for Cd, respectively. The results of the four certified reference materials were satisfied; there was no significant difference compared with the ICP-MS method according to a
-test, and the RSDs were less than 5% for Cd and Pb. The recoveries of naturally contaminated samples compared with the ICP-MS method were favorable, with 80-110% in eight laboratories. The developed method is rapid, low-cost, and highly automated and may be a good choice for grain quality discrimination and rapid analysis of Cd and Pb in different institutions.
The traditional pretreatment methods for the determination of cadmium in grain are time-consuming, cost-consuming, and unfriendly to human health and the environment. To eliminate these ...disadvantages, we developed an accurate, time-, energy- and cost-efficient method for determination of Cd in grain coupled with graphite furnace atomic absorption spectrometry (GFAAS). The optimization conditions of the extraction were achieved, the accuracy was verified and a collaborative study was organized to evaluate the methods. The detection limit and quantification limit were 0.016 and 0.048 μg L−1, respectively. The whole pretreatment time was reduced to 15 min, and there was no significant difference (P >0.05) between the extraction method and the classic pretreatment method. The method proved to be highly consistent with the results of laboratories in different countries, as determined from two international proficiency tests (| Z | ≤0.3). The repeatability, reproducibility, and HorRat values of the collaborative results were 2.7 – 4.9%, 9.4 – 11.7%, and 0.42 – 0.58, respectively. The method of diluted acid mild extraction coupled with GFAAS is efficient, cost-saving, convenient and friendly.
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•Adding the Cu led to the formation of Cr-enriched precipitates in the matrix.•The Cr7C3 precipitate in the CoCrMo-4Cu was partially coherent with Cu nanoparticle.•The Cr-enriched ...precipitates were the critical contributor to enhancing the tribology property.•The corrosion resistance of CoCrMo alloy was enhanced as the 2 and 3 wt% Cu added into CoCrMo alloy.
In this study, the cobalt-chromium-molybdenum (CoCrMo) alloys containing varying Cu contents (CCM-xCu, x = 0, 2, 3, 4 wt%) were fabricated via the selected laser melting (SLM) method. The influences of Cu content on tribological performance and corrosion resistance were investigated. The 2 and 3 wt% Cu contributed to inhibiting the generation of the HCP phase, whereas the inhibitory effect was quite limited at 4 wt% Cu. Notably, 4 wt% Cu led to the formation of Cr-enrich precipitates in the matrix, which was partially coherent with the Cu nanoparticle. The corrosion resistance of the CCM alloy was enhanced as the 2 and 3 wt% Cu added into the CCM alloy, contrarily, which deteriorated when Cu content reached 4 wt%. For the CCM-2Cu and CCM-3Cu, Cr-precipitates played a major role in enhancing the wear resistance, while the Cu lubrication effect working in coordination with Cr-precipitates determined that for the CCM-4Cu. This study was expected to achieve better tribology and corrosion properties of SLM-produced CCM alloys by tailoring microstructure through the Cu element.
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