The DVD vs. DIVX Standard War: Empirical Evidence of Vaporware

In this paper, we empirically measure the effect of the DIVX preannouncement in the DVD market. We do this by measuring the effect of potential (incompatible) competition on a network undergoing growth. We find that there are network effects in the DVD market and that the preannouncement of DIVX slowed down the adoption of DVD technology. This suggests that strategic preannouncements can indeed affect the outcome of a standards competition.

Indirect Network Effects and Adoption Externalities

The conventional wisdom is that indirect network effects, unlike direct network effects, do not give rise to externalities. In this paper we show that under very general conditions, indirect network effects lead to adoption externalities. In particular we show that in markets where consumption benefits arise from hardware/software systems, adoption externalities will occur when there are (i) increasing returns to scale in the production of software, (ii) free-entry in software, and (iii) consumers have a preference for software variety. The private benefit of the marginal hardware purchaser is less than the social benefit since the marginal hardware purchaser does not internalize the welfare improving response of the software industry, particularly the increase in software variety, on inframarginal purchasers when the market for hardware expands.Network Externalities, Network Effects

Feminist Methods and Sources in Criminology and Criminal Justice

In this article Dr Adrian Howe discusses the usefulness of feminist approaches to research in the fields of criminology and criminal justice. She describes how standard positivist methodologies as well as newly emergent poststructuralist approaches, such as Foucauldian methods, are bringing much needed new perspectives to criminological issues

The rise and fall of cryptocurrency coins and tokens

Since Bitcoin’s introduction in 2009, interest in cryptocurrencies has soared. One manifestation of this interest has been the explosion of newly created coins and tokens. In this paper, we analyze the dynamics of this burgeoning industry. We consider both cryptocurrency coins and tokens. The paper examines the dynamics of coin and token creation, competition and destruction in the cryptocurrency industry. In order to conduct the analysis, we develop a methodology to identify peaks in prices and trade volume, as well as when coins and tokens are abandoned and subsequently “resurrected”. We also study trading activity. Our data spans more than 4 years: there are 1082 coins and 725 tokens in the data. While there are some similarities between coins and tokens regarding dynamics, there are some striking differences as well. Overall, we find that 44% of publicly-traded coins are abandoned, at least temporarily. 71% of abandoned coins are later resurrected, leaving 18% of coins to fail permanently. Tokens experience abandonment less frequently, with only 7% abandonment and 5% permanent token abandonment at the end of the data. Using linear regressions, we find that market variables such as the bitcoin price are not associated with the rate of introducing new coins, though they are positively associated with issuing new tokens. We find that for both coins and tokens, market variables are positively associated with resurrection. We then examine the effect that the bursting of the Bitcoin bubble in December 2017 had on the dynamics in the industry. Unlike the end of the 2013 bubble, some alternative cryptocurrencies continue to flourish after the bursting of this bubble

mGluR5-Antagonist Mediated Reversal of Elevated Stereotyped, Repetitive Behaviors in the VPA Model of Autism

Autism spectrum disorders (ASD) are highly disabling developmental disorders with a population prevalence of 1–3%. Despite a strong genetic etiology, there are no current therapeutic options that target the core symptoms of ASD. Emerging evidence suggests that dysfunction of glutamatergic signaling, in particular through metabotropic glutamate receptor 5 (mGluR5) receptors, may contribute to phenotypic deficits and may be appropriate targets for pharmacologic intervention. This study assessed the therapeutic potential of 2-methyl-6-phenylethyl-pyrididine (MPEP), an mGluR5-receptor antagonist, on repetitive and anxiety-like behaviors in the valproic acid (VPA) mouse model of autism. Mice were exposed prenatally on day E13 to VPA and assessed for repetitive self-grooming and marble burying behaviors as adults. Anxiety-like behavior and locomotor activity were measured in an open-field. VPA-exposed mice displayed increased repetitive and anxiety-like behaviors, consistent with previously published results. Across both marble burying and self-grooming assays, MPEP significantly reduced repetitive behaviors in VPA-treated mice, but had no effect on locomotor activity. These results are consistent with emerging preclinical literature that mGluR5-antagonists may have therapeutic efficacy for core symptoms of autism

Microstructure of Collaboration: The Network of Open Source Software

The open source model is a form of software development with source code that is typically made available to all interested parties. At the core of this process is a decentralized production process: open source software development is done by a network of unpaid software developers. Using data from Sourceforge.net, the largest repository of Open Source Software (OSS) projects and contributors on the Internet, we construct two related networks: A Project network and a Contributor network. Knowledge spillovers may be closely related to the structure of such networks, since contributors who work on several projects likely exchange information and knowledge. Defining the number of downloads as output we finds that (i) additional contributors are associated with an increase in output, but that additional contributors to projects in the giant component are associated with greater output gains than additional contributors to projects outside of the giant component; (ii) Betweenness centrality of the project is positively associated with the number of downloads. (iii) Closeness centrality of the project appears also to be positively associated with downloads, but the effect is not statistically significant over all specifications. (iv) Controlling for the correlation between these two measures of centrality (betweenness and closeness), the degree is not positively associated with the number of downloads. (v) The average closeness centrality of the contributors that participated in a project is positively correlated with the success of the project. These results suggest that there are positive spillovers of knowledge for projects occupying critical junctures in the information flow. When we define projects as connected if and only if they had at least two contributors in common, we again find that additional contributors are associated with an increase in output, and again find that this increase is much higher for projects with strong ties than other projects in the giant component