25,189 research outputs found
Economics and the new economy: the invisible hand meets creative destruction
In the 18th century, Adam Smith offered his theory of the invisible hand and the view that perfect competition is the main spur to economic efficiency. The theory of the invisible hand, as it has evolved in modern economic thought, treats creative activity as being outside the scope of economic theory. In the 20th century, Joseph Schumpeter offered an alternative perspective: creativity is an economic activity. He argued that a capitalist market system rewards change by allowing those who create new products and processes to capture some of the benefits of their creations in the form of short-term monopoly profits, a situation that promotes what Schumpeter called "creative destruction." What should the fundamental paradigm of economics be: creative destruction or the invisible hand? In this article, Leonard Nakamura offers some possible answers to this question.[Adobe Acrobat (.pdf)Economic development ; Productivity ; Wages
Semantic Heterogeneity Issues on the Web
The Semantic Web is an extension of the traditional Web in which meaning of information is well defined, thus allowing a better interaction between people and computers. To accomplish its goals, mechanisms are required to make explicit the semantics of Web resources, to be automatically processed by software agents (this semantics being described by means of online ontologies). Nevertheless, issues arise caused by the semantic heterogeneity that naturally happens on the Web, namely redundancy and ambiguity. For tackling these issues, we present an approach to discover and represent, in a non-redundant way, the intended meaning of words in Web applications, while taking into account the (often unstructured) context in which they appear. To that end, we have developed novel ontology matching, clustering, and disambiguation techniques. Our work is intended to help bridge the gap between syntax and semantics for the Semantic Web construction
Shikimate hydroxycinnamoyl transferase (HCT) activity assays in Populus nigra
Lignin is a complex phenolic polymer deposited in secondarily-thickened plant cell walls. The polymer is mainly derived from the three primary monolignols: p-coumaryl, coniferyl and sinapyl alcohol which give rise to p-hydroxyphenyl, guaiacyl and syringyl units (H, G and S units, respectively) when coupled into the polymer. The building blocks differ in their degree of methoxylation and their biosynthetic pathway is catalyzed by more than 10 enzymes. HCT plays a crucial role by channeling the phenylpropanoids towards the production of coniferyl and sinapyl alcohols. Interestingly, HCT has been reported to be implicated in the pathway both upstream and downstream of the 3-hydroxylation of the aromatic ring of p-coumaroyl shikimate (Figure 1) (Hoffmann et al., 2003; Hoffmann et al., 2004; Vanholme et al., 2013b). These features highlight the importance of developing an assay to reliably measure HCT activity in planta. Here, we describe a UPLC-MS-based method for the analysis of HCT activity in xylem total protein extracts of Populus nigra, which can be adapted to other woody and herbaceous plant species. The protocol was initially described in Vanholme et al. (2013a)
The "Artificial Mathematician" Objection: Exploring the (Im)possibility of Automating Mathematical Understanding
Reuben Hersh confided to us that, about forty years ago, the late Paul Cohen predicted to him that at some unspecified point in the future, mathematicians would be replaced by computers. Rather than focus on computers replacing mathematicians, however, our aim is to consider the (im)possibility of human mathematicians being joined by “artificial mathematicians” in the proving practice—not just as a method of inquiry but as a fellow inquirer
Automated reduction of submillimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using ORAC-DR
With the advent of modern multi-detector heterodyne instruments that can
result in observations generating thousands of spectra per minute it is no
longer feasible to reduce these data as individual spectra. We describe the
automated data reduction procedure used to generate baselined data cubes from
heterodyne data obtained at the James Clerk Maxwell Telescope. The system can
automatically detect baseline regions in spectra and automatically determine
regridding parameters, all without input from a user. Additionally it can
detect and remove spectra suffering from transient interference effects or
anomalous baselines. The pipeline is written as a set of recipes using the
ORAC-DR pipeline environment with the algorithmic code using Starlink software
packages and infrastructure. The algorithms presented here can be applied to
other heterodyne array instruments and have been applied to data from
historical JCMT heterodyne instrumentation.Comment: 18 pages, 13 figures, submitted to Monthly Notices of the Royal
Astronomical Societ
Edaq530: a transparent, open-end and open-source measurement solution in natural science education
We present Edaq530, a low-cost, compact and easy-to-use digital measurement
solution consisting of a thumb-sized USB-to-sensor interface and a measurement
software. The solution is fully open-source, our aim being to provide a viable
alternative to professional solutions. Our main focus in designing Edaq530 has
been versatility and transparency. In this paper, we shall introduce the
capabilities of Edaq530, complement it by showing a few sample experiments, and
discuss the feedback we have received in the course of a teacher training
workshop in which the participants received personal copies of Edaq530 and
later made reports on how they could utilise Edaq530 in their teaching
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