149 research outputs found
Citizen science and crowdsourcing for Earth observations: An analysis of stakeholder opinions on the present and future
The impact of Crowdsourcing and citizen science activities on academia, businesses, governance and society has been enormous. This is more prevalent today with citizens and communities collaborating with organizations, businesses and authorities to contribute in a variety of manners, starting from mere data providers to being key stakeholders in various decision-making processes. The âCrowdsourcing for observations from Satellitesâ project is a recently concluded study supported by demonstration projects funded by European Space Agency (ESA). The objective of the project was to investigate the different facets of how crowdsourcing and citizen science impact upon the validation, use and enhancement of Observations from Satellites (OS) products and services. This paper presents our findings in a stakeholder analysis activity involving participants who are experts in crowdsourcing, citizen science for Earth Observations. The activity identified three critical areas that needs attention by the community as well as provides suggestions to potentially help in addressing some of the challenges identified
Extremal Optimization of Graph Partitioning at the Percolation Threshold
The benefits of a recently proposed method to approximate hard optimization
problems are demonstrated on the graph partitioning problem. The performance of
this new method, called Extremal Optimization, is compared to Simulated
Annealing in extensive numerical simulations. While generally a complex
(NP-hard) problem, the optimization of the graph partitions is particularly
difficult for sparse graphs with average connectivities near the percolation
threshold. At this threshold, the relative error of Simulated Annealing for
large graphs is found to diverge relative to Extremal Optimization at equalized
runtime. On the other hand, Extremal Optimization, based on the extremal
dynamics of self-organized critical systems, reproduces known results about
optimal partitions at this critical point quite well.Comment: 7 pages, RevTex, 9 ps-figures included, as to appear in Journal of
Physics
Canonical Wnt/Î-catenin signaling is required for maintenance but not activation of Pitx2 expression in neural crest during eye development
Pitx2 is a paired-like homeodomain gene that acts as a key regulator of eye development. Despite its significance, upstream regulation of Pitx2 expression during eye development remains incompletely understood. We use neural crest-specific ablation of Ctnnb1 to demonstrate that canonical Wnt signaling is not required for initial activation of Pitx2 in neural crest. However, canonical Wnt signaling is subsequently required to maintain Pitx2 expression in the neural crest. Eye development in Ctnnb1 -null mice appears grossly normal early but significant phenotypes emerge following loss of Pitx2 expression. LEF-1 and Î-catenin bind Pitx2 promoter sequences in ocular neural crest, indicating a likely direct effect of canonical Wnt signaling on Pitx2 expression. Combining our data with previous reports, we propose a model wherein a sequential code of retinoic acid followed by canonical Wnt signaling are required for activation and maintenance of Pitx2 expression, respectively. Other key transcription factors in the neural crest, including Foxc1 , do not require intact canonical Wnt signaling. Developmental Dynamics 239:3215â3225, 2010. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78327/1/22459_ftp.pd
Wolves in the Wolds: Late Capitalism, the English Eerie, and the Wyrd Case of âOld Stinkerâ the Hull Werewolf
In this article, I depart from the earlier opinions of Emily Gerard, Sabine Baring-Gould, and others, who explained the disappearance of the werewolf in folklore as following the extinction of the wolf. I argue instead that British literature is distinctive in representing a history of werewolf sightings in places in Britain where there were once wolves. I draw on the idea of absence, manifestations of the English eerie, and the turbulence of England in the era of late capitalism to illuminate my analysis of the representation of contemporary werewolf sightingsPeer reviewe
Molecular and supramolecular chemistry of mono- and di-selenium analogues of metal dithiocarbamates
This bibliographic review summarises the coordination chemistry of mono- and diselenium analogues of metal dithiocarbamate ligands, [RRêNCS2]-, as revealed by X-ray
crystallography and spectroscopy (77Se NMR and infrared). The Se-ligands are usually chelating but, bridging modes, up to 4, are known. Reflecting the larger size, greater
polarisability and presence of a polar-cap (-hole), selenium atoms are more likely to be involved in secondary-bonding (chalcogen-bonding) than sulphur when a competition exists. Isostructural relationships are established across the series in about one-third of the structures
Crowdsourcing Controls: A Review and Research Agenda for Crowdsourcing Controls Used for Macro-tasks
Crowdsourcingâthe employment of ad hoc online labor to perform various tasksâhas become a popular outsourcing vehicle. Our current approach to crowdsourcingâfocusing on micro-tasksâfails to leverage the potential of crowds to tackle more complex problems. To leverage crowds to tackle more complex macro tasks requires a better comprehension of crowdsourcing controls. Crowdsourcing controls are mechanisms used to align crowd workersâ actions with predefined standards to achieve a set of goals and objectives. Unfortunately, we know very little about the topic of crowdsourcing controls directed at accomplishing complex macro tasks. To address issues associated with crowdsourcing controls formacro-tasks, this chapter has several objectives. First, it presents and discusses the literature on control theory. Second, this chapter presents a scoping literature review of crowdsourcing controls. Finally, the chapter identifies gaps and puts forth a research agenda to address these shortcomings. The research agenda focuses on understanding how to employ the controls needed to perform macro-tasking in crowds and the implications for crowdsourcing system designers.National Science Foundation grant CHS-1617820Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150493/1/Robert 2019 Preprint Chapter 3.pdfDescription of Robert 2019 Preprint Chapter 3.pdf : PrePrint Versio
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