459 research outputs found

    Financing Invention During the Second Industrial Revolution: Cleveland, Ohio, 1870-1920

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    For those who think of Cleveland as a decaying rustbelt city, it may seem difficult to believe that this northern Ohio port was once a hotbed of high-tech startups, much like Silicon Valley today. During the late nineteenth and early twentieth centuries, Cleveland played a leading role in the development of a number of second-industrial-revolution industries, including electric light and power, steel, petroleum, chemicals, and automobiles. In an era when production and inventive activity were both increasingly capital-intensive, technologically creative individuals and firms required greater and greater amounts of funds to succeed. This paper explores how the city's leading inventors and technologically innovative firms obtained financing, and finds that formal institutions, such as banks and securities markets, played only a very limited role. Instead, most funding came from local investors who took long-term stakes in start-ups formed to exploit promising technological discoveries, often assuming managerial positions in these enterprises as well. Business people who were interested in investing in cutting-edge ventures needed help in deciding which inventors and ideas were most likely to yield economic returns, and we show how enterprises such as the Brush Electric Company served multiple functions for the inventors who flocked to work there. Not only did they provide forums for the exchange of ideas, but by assessing each other's discoveries, the members of these technological communities conveyed information to local businessmen about which inventions were most worthy of support.

    Improved Algorithms for Approximate String Matching (Extended Abstract)

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    The problem of approximate string matching is important in many different areas such as computational biology, text processing and pattern recognition. A great effort has been made to design efficient algorithms addressing several variants of the problem, including comparison of two strings, approximate pattern identification in a string or calculation of the longest common subsequence that two strings share. We designed an output sensitive algorithm solving the edit distance problem between two strings of lengths n and m respectively in time O((s-|n-m|)min(m,n,s)+m+n) and linear space, where s is the edit distance between the two strings. This worst-case time bound sets the quadratic factor of the algorithm independent of the longest string length and improves existing theoretical bounds for this problem. The implementation of our algorithm excels also in practice, especially in cases where the two strings compared differ significantly in length. Source code of our algorithm is available at http://www.cs.miami.edu/\~dimitris/edit_distanceComment: 10 page

    On Approximately Symmetric Informationally Complete Positive Operator-Valued Measures and Related Systems of Quantum States

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    We address the problem of constructing positive operator-valued measures (POVMs) in finite dimension nn consisting of n2n^2 operators of rank one which have an inner product close to uniform. This is motivated by the related question of constructing symmetric informationally complete POVMs (SIC-POVMs) for which the inner products are perfectly uniform. However, SIC-POVMs are notoriously hard to construct and despite some success of constructing them numerically, there is no analytic construction known. We present two constructions of approximate versions of SIC-POVMs, where a small deviation from uniformity of the inner products is allowed. The first construction is based on selecting vectors from a maximal collection of mutually unbiased bases and works whenever the dimension of the system is a prime power. The second construction is based on perturbing the matrix elements of a subset of mutually unbiased bases. Moreover, we construct vector systems in \C^n which are almost orthogonal and which might turn out to be useful for quantum computation. Our constructions are based on results of analytic number theory.Comment: 29 pages, LaTe

    Delays in Leniency Application: Is There Really a Race to the Enforcer's Door?

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    This paper studies cartels’ strategic behavior in delaying leniency applications, a take-up decision that has been ignored in the previous literature. Using European Commission decisions issued over a 16-year span, we show, contrary to common beliefs and the existing literature, that conspirators often apply for leniency long after a cartel collapses. We estimate hazard and probit models to study the determinants of leniency-application delays. Statistical tests find that delays are symmetrically affected by antitrust policies and macroeconomic fluctuations. Our results shed light on the design of enforcement programs against cartels and other forms of conspiracy

    Collusion through Joint R&D: An Empirical Assessment

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    This paper tests whether upstream R&D cooperation leads to downstream collusion. We consider an oligopolistic setting where firms enter in research joint ventures (RJVs) to lower production costs or coordinate on collusion in the product market. We show that a sufficient condition for identifying collusive behavior is a decline in the market share of RJV-participating firms, which is also necessary and sufficient for a decrease in consumer welfare. Using information from the US National Cooperation Research Act, we estimate a market share equation correcting for the endogeneity of RJV participation and R&D expenditures. We find robust evidence that large networks between direct competitors – created through firms being members in several RJVs at the same time – are conducive to collusive outcomes in the product market which reduce consumer welfare. By contrast, RJVs among non-competitors are efficiency enhancing

    Virtual money, practices and moral orders in Second Life

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    Virtual monies present a limit case in debates about money's moral and political entanglements between sociologists, anthropologists, and economists. Digitized virtual monies seem ephemeral, almost ideal typical examples of money as a pure medium of exchange. This paper begins with the premise that virtual monies are as value-laden and morally entangled as any other form of money. This assertion is demonstrated by exploring how one type of virtual money, the Linden dollar (L$), and some of its associated practices are bound up with research participants' moral categories and judgments in the virtual world of Second Life (SL). Participants' accounts of virtual money practices are linked to moral attributes, sometimes in stark ‘good’ or ‘bad’ dichotomies, but also in more nuanced terms. These framings reproduce classifications of people and practices along a continuum with virtuousness at one end and maliciousness or harm at the other, passing through various states of possible moral dubiousness. For respondents, these two judgments go together; people are what they do with money. As a result, respondents decide what ‘people like that’ deserve. Evaluating someone's money practices means assessing the person. Participants' accounts of Linden dollar practices overlap with explanations of what SL is and how residents should live there. In SL, money is a form of material culture through which appropriate ways of being in the world are debated and reproduced

    Environmental Factors in the Relapse and Recurrence of Inflammatory Bowel Disease:A Review of the Literature

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    The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability

    Dynamic Crystallization Pathways of Polymorphic Pharmaceuticals Revealed in Segmented Flow with Inline Powder X-ray Diffraction

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    Understanding the transitions between polymorphs is essential in the development of strategies for manufacturing and maximizing the efficiency of pharmaceuticals. However, this can be extremely challenging: crystallization can be influenced by subtle changes in environment, such as temperature and mixing intensity or even imperfections in the crystallizer walls. Here, we highlight the importance of in situ measurements in understanding crystallization mechanisms, where a segmented flow crystallizer was used to study the crystallization of the pharmaceuticals urea: barbituric acid (UBA) and carbamazepine (CBZ). The reactor provides highly reproducible reaction conditions, while in situ synchrotron powder X-ray diffraction (PXRD) enables us to monitor the evolution of this system. UBA has two polymorphs of almost equivalent free-energy and so is typically obtained as a polymorphic mixture. In situ PXRD analysis uncovered a progression of polymorphs from UBA III to the thermodynamic polymorph UBA I, where different positions along the length of the tubular flow crystallizer correspond to different reaction times. Addition of UBA I seed crystals modified this pathway such that only UBA I was observed throughout, while transformation from UBA III into UBA I still occurred in the presence of UBA III seeds. Information regarding the mixing-dependent kinetics of the CBZ form II to III transformation was also uncovered in a series of seeded and unseeded flow crystallization runs, despite atypical habit expression. These results illustrate the importance of coupling controlled reaction environments with in situ XRD to study the phase relationships in polymorphic materials

    Determinants of self-reporting under the European corporate leniency program

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    We empirically investigate the determinants of self-reporting under the European corporate leniency program. Applying a data set consisting of 442 firm groups that participated in 76 cartels decided by the European Commission between 2000 and 2011, we find that the probability of a firm becoming the chief witness increases with its character as repeat offender, the size of the expected basic fine, the number of countries active in one group as well as the size of the firm’s share in the cartelized market. Our results have important implications for an effective prosecution of anti-cartel law infringers

    White Matter Changes in Cervical Dystonia Relate to Clinical Effectiveness of Botulinum Toxin Treatment

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    In a previous report showing white matter microstructural hemispheric asymmetries medial to the pallidum in focal dystonias, we showed preliminary evidence that this abnormality was reduced 4 weeks after botulinum toxin (BTX) injections. In the current study we report the completed treatment study in a full-size cohort of CD patients (n = 14). In addition to showing a shift toward normalization of the hemispheric asymmetry, we evaluated clinical relevance of these findings by relating white matter changes to degree of symptom improvement. We also evaluated whether the magnitude of the white matter asymmetry before treatment was related to severity, laterality, duration of dystonia, and/or number of previous BTX injections. Our results confirm the findings of our preliminary report: we observed significant fractional anisotropy (FA) changes medial to the pallidum 4 weeks after BTX in CD participants that were not observed in controls scanned at the same interval. There was a significant relationship between magnitude of hemispheric asymmetry and dystonia symptom improvement, as measured by percent reduction in dystonia scale scores. There was also a trend toward a relationship between magnitude of pre-injection white matter asymmetry and symptom severity, but not symptom laterality, disorder duration, or number of previous BTX injections. Post-hoc analyses suggested the FA changes at least partially reflected changes in pathophysiology, but a dissociation between patient perception of benefit from injections and FA changes suggested the changes did not reflect changes to the primary “driver” of the dystonia. In contrast, there were no changes or group differences in DTI diffusivity measures, suggesting the hemispheric asymmetry in CD does not reflect irreversible white matter tissue loss. These findings support the hypothesis that central nervous system white matter changes are involved in the mechanism by which BTX exerts clinical benefit
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