What Inspires Leisure Time Invention?

This paper seeks to understand the intriguing but only sparsely explored phenomenon of “leisure time invention,” where the main underlying idea for the new product or process occurs when the inventor is away from the workplace. We add to previous research by focussing on the inventive creativity of the individual researcher, and reassessing the image of researchers inventing during unpaid time – who have often been dispatched as “hobbyists”. Based on the responses from a survey of over 3,000 German inventors, we tested hypotheses on the conditions under which leisure time invention is likely to arise. Results suggest that the incidence of leisure time invention is positively related to exposure to a variety of knowledge inputs – but, surprisingly, not to the quality of prior inventive output. Leisure time inventions are more frequently observed in conceptual-based technologies than in science-based technologies, in smaller R&D projects, and in externally financed R&D projects

What Inspires Leisure Time Invention?

This paper seeks to understand the intriguing but only sparsely explored phenomenon of “leisure time invention,” where the main underlying idea for the new product or process occurs when the inventor is away from the workplace. We add to previous research by focussing on the inventive creativity of the individual researcher, and reassessing the image of researchers inventing during unpaid time – who have often been dispatched as “hobbyists”. Based on the responses from a survey of over 3,000 German inventors, we tested hypotheses on the conditions under which leisure time invention is likely to arise. Results suggest that the incidence of leisure time invention is positively related to exposure to a variety of knowledge inputs – but, surprisingly, not to the quality of prior inventive output. Leisure time inventions are more frequently observed in conceptual-based technologies than in science-based technologies, in smaller R&D projects, and in externally financed R&D projects.Leisure Time; Inventiveness; Organizational Creativity

Black Businesses and Their Lawyers

The purpose of this article is to report the results of a study which we conducted to determine the ethnicity of lawyers representing the largest black businesses in the country, and secondly, to make some observations about the future of the black attorney and his relationship with both black and white businesses

Do Patents "Crowd Out” Prizes?

Debate over the merits of patents versus inducement prizes has tended to ignore the signaling roles of patents, and totally ignores the impact of patent signaling on prize contests. This paper asks: How does patent signaling affect the strategic choices of firms considering entering prize contests? First, we consider contests that do not allow patenting, then contests that do. If patenting is not allowed, we argue, patent-holders, both internal and external to the contest, can adversely impact prize contests by claiming prize winner violation of their patents, and suing for damages. The likelihood of such challenges being made can deter entry, particularly in contests requiring large sunk costs. Furthermore, the firm's decisionmaking process will discriminate against entering prize contests and favor R&D projects with patentable outcomes. Together, these problems may circumscribe any future wider role for prize contests, and limit their major putative welfare advantage: the ability to place prize winning solutions into the public domain. In contests where entrants may patent their inventions, entry is subject to basically the same problems as above (although such contests may carry some advantages as regards contest design). Our overall conclusion is that prize contests are liable to fail due to the lack of potential entrants, particularly as regards entry on the part of larger commercial firms

Precise Measurement of the Spin Parameter of the Stellar-Mass Black Hole M33 X-7

In prior work, {\it Chandra} and Gemini-North observations of the eclipsing X-ray binary M33 X-7 have yielded measurements of the mass of its black hole primary and the system's orbital inclination angle of unprecedented accuracy. Likewise, the distance to the binary is known to a few percent. In an analysis based on these precise results, fifteen {\it Chandra} and {\it XMM-Newton} X-ray spectra, and our fully relativistic accretion disk model, we find that the dimensionless spin parameter of the black hole primary is $a_* = 0.77 \pm 0.05$. The quoted 1-$\sigma$ error includes all sources of observational uncertainty. Four {\it Chandra} spectra of the highest quality, which were obtained over a span of several years, all lead to the same estimate of spin to within statistical errors (2%), and this estimate is confirmed by 11 spectra of lower quality. There are two remaining uncertainties: (1) the validity of the relativistic model used to analyze the observations, which is being addressed in ongoing theoretical work; and (2) our assumption that the black hole spin is approximately aligned with the angular momentum vector of the binary, which can be addressed by a future X-ray polarimetry mission.Comment: 14 pages, 3 figures, 1 table, published in ApJ Letters; as explained in the erratum at the end of the text, the spin parameter has been corrected upward from a*=0.77 to a*=0.84. Apart from the addition of the erratum, the paper is unchanged

Investigations into the larval rearing of two South African sparid species

The most significant bottleneck to the development of marine finfish culture is a reliable production of juveniles for growout. This is due to the small size at hatch and delicate nature of the pelagic larvae produced by most commercially desirable species. However, over the last 30 years, improved larviculture techniques have been developed to the extent that many species are being successfully cultured worldwide. These techniques were applied to two endemic species as a preliminary step towards establishing marine finfish aquaculture in South Africa. Adult roman Chtysoblephus laticeps and carpenter Argyrozona argyrozona (Pisces: Sparidae) were caught in the Tsitsikamma National Park. Both species responded to injection with pituitary extract, HCG and LHRHa, and were succesfully stripped up to 48 hours after injection. Fish were stripped twice, the second stripping producing better quality eggs. Chyrysoblephus laticeps also spawned naturally after injection with LHRHa. The fertilised eggs were incubated and the larvae reared in a fully recirculating seawater system. One batch of A. argyrozona and three batches of C. laticeps were reared through metamorphosis on a diet of enriched rotifers and Anemia, and inert foods, following commonly used rearing procedures. Both species followed developmental patterns of other cultured larvae, displaying typical critical stages; high mortalities at first-feeding and cannibalism from 26-30 days after hatch resulted in survival rates ranging from 0.1-0.5%. Growth, survival, size of gape at first-feeding, and ease of weaning onto an inert diet of C. laticeps was comparable to other species being reared for the first time, indicating some potential as a candidate species. The numbers of A. argyrozona larvae reared were insufficient to make comparisons with other studies. The adults also proved to be susceptible to physical damage while in captivity and were, therefore, considered unsuitable for aquaculture. The thesis describes the spawning procedure, the systems developed and the larval rearing process. The critical stages of first-feeding, swim bladder inflation, settlement and cannibalism are discussed and the development of the larvae described. The ontogeny of both species is described in detail. Both species displayed typical sparid developmental patterns, but differed with respect to pigmentation, head spination and morphometrics

The New International Economic Order and the Problem of Access: A Market Structure Point of View

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