Optimal Tc_c of cuprates: role of screening and reservoir layers

We explore the role of charge reservoir layers (CRLs) on the superconducting transition temperature of cuprate superconductors. Specifically, we study the effect of CRLs with efficient short distance dielectric screening coupled capacitively to copper oxide metallic layers. We argue that dielectric screening at short distances and at frequencies of the order of the superconducting gap, but small compared to the Fermi energy can significantly enhance T$_c$, the transition temperature of an unconventional superconductor. We discuss the relevance of our qualitative arguments to a broader class of unconventional superconductors.Comment: 8 Pages, 4 figure

It’s Not All About the Music: User Preference for Musicians on Facebook

To better understand hedonic utility of social media users, we conducted a study among university students using musicians’ Facebook pages for digital content consumption. Our study measures the effects of peer influence and media richness as subjects evaluated different musician’s pages with different levels of both effects. The results show support for our key hypothesis that social media users are influenced by peer influence in making choices to “like” something. More importantly, the key aspects of the product (in our case, music) were less of a predictor of consumer choice

Product Portfolio and Mobile Apps Success: Evidence from App Store Market

This research empirically analyzes seller’s product portfolio strategy in the mobile application (apps) market. We use crosssectionaldata on the most downloaded application rankings in the Apple App Store to examine the impact of app portfoliostrategy on sales performance. We find that app portfolio diversification is positively correlated with sales performance. Wealso find that sellers who offer a combination of free and paid apps have higher sales performance than those who deliverpaid apps only. Furthermore, the results show that sellers with scale advantages compete differently from sellers in the longtail. These findings have implications for theorizing about product portfolio management in the emerging mobile app storemarkets

Market Reactions to Intellectual Property Infringement Litigations in the Information Technology Industry

The information technology industry is characterized by constant innovation and substantial expenditures on research and development. Firms attempt to protect their investment in research and development and retain a competitive edge in the industry by obtaining patents and copyrights. These intellectual properties are important intangible assets that are evaluated by the financial markets and can be observed in the market price at which the common stock is traded. If a firm announces a lawsuit claiming that its intellectual property has been violated, the markets have to form an opinion about several matters, viz. the merit of the lawsuit, the probability of a verdict favoring either party, the damages which will be awarded, if any, and managerial time and effort expended in the process. We are unable to observe these inputs, but can measure the impact of these factors on the stock price

Market Reactions To Patent Infringement Lawsuits In Information Technology Industry

Over the years the number of patent infringement lawsuits in the Information Technology industry has increased tremendously. The increase in patent disputes can be partly attributed to the increase in the number of patents issued. The number of patents issued for software developments alone has risen from 25 in 1970 to 600 in 1991. The total number of patents issued till 1992 was about 9000. The damages awarded to patentees in such litigations is substantial. It is argued that some of these high technology companies are using the intellectual property rights laws as a weapon to thwart competition in their markets. In the US, while the inventor is waiting for the patent on the invention, manufacturers may develop and begin using similar technology, but once the patent has been issued, the inventor can demand the damages from the manufacturer using the technology. Many of the top executives believe that it is beneficial to settle infringement cases than dispute it in a court of law. This view is again raised in the patent infringement dispute between Intel Corp. and AMD Corp., who spent almost $200 million on the patent dispute over several years. To our knowledge no empirical study has been undertaken to study the impact of patent infringement lawsuits on the information technology companies involved. Though markets analysts have suggested that the market value of the firms fluctuates in accordance with the direction of the lawsuit proceedings, no concrete evidence of these effects have been shown in the literature. This study aims to study the impact of the patent infringement lawsuits and the lawsuit decisions on the IT companies involved. The impact on the stock holder returns is used as the empirical evidence of the impact of the litigation on the IT company. Findings of thestudy are expected to provide valuable insights into market perception of the ethical issues in a high technology industry. More specifically, how does the market view the ethical conduct of an IT company? Does it impose a high risk on a company suspectedof unethical conduct in its business strategies?. In addition to the ethical issues involved, the economic viability of fighting a law suit is also examined, i.e., does the market perceive a net benefit or loss to the company as a result of fighting a lawsuit? Does the market perceive a net benefit or loss to the company as a result of the decision made on the law suit?. The findings of the study would be useful to both the policy formulators and managers alik

Heads or Tails? Network Effects on Game Purchase Behavior in The Long Tail Market

This study aims to uncover the effects of network effects, namely the social influence and network externalities, on purchasing of digital goods. We are particularly interested in the differences in network effects in long tail versus the head of the market. We used a novel dataset from an online game distribution platform covering 1975 games and 8000 users in this study. The results reveal that network effects are more pronounced for the tail of the market in comparison to the head of the market. For the games that are in the head of the market the popularity may be more significantly influenced by factors unobserved in this study (such as advertising budget) yet the games in the tail benefited greatly from any change to the network effects. The exception was social games. The games that relied on user to user engagement did not fare well in the tail of the market. This study contributes to the literature on network effects and long tail market literature by highlighting the differential effects in different segments of the market

Modeling IS Activities for Business Process Reengineering : A Colored Petri Net Approach

The day to day functioning of any organization involves many business processes. Each business process is comprised of different activities. The identification of activities and their cost drivers is a critical factor for successful Business Process Reengineering. Since the resources used by the activities form an integral part of the model, the identification of the cost drivers is also simplified. This paper details the following : 1. It proposesthe use of colored Petri nets for process modeling. Brimson(1991) identifies the process modeling approach to activity analysis as useful since it graphically links the inputs and outputs among activities and identifies the information flow in the processes. However, use of process flow charts, which is most commonly used in activity analysis cannot capture some of the aspects of office processes, like supervision, general management, etc. In addition, representing the complex business logic associated with activities would be difficult in such flow models. The use of colored Petri nets overcomes this limitation, as business logic and various office processes can be easily represented. In addition, the complexity of the system is handled by resorting to hierarchical representation of the processes. 2. The paper applies the concept of activity based costing to the management of the IS processes in firms. The cost structure of these processes, to our knowledge, has not been studied from the activity based costing perspective. The article proposes the use of activity based costing for IS processes. Such analysis could help the organization in making operational as well as strategic decisions as related to its IS processe

Majorana zero modes in a quantum Ising chain with longer-ranged interactions

A one-dimensional Ising model in a transverse field can be mapped onto a system of spinless fermions with p-wave superconductivity. In the weak-coupling BCS regime, it exhibits a zero energy Majorana mode at each end of the chain. Here, we consider a variation of the model, which represents a superconductor with longer ranged kinetic energy and pairing amplitudes, as is likely to occur in more realistic systems. It possesses a richer zero temperature phase diagram and has several quantum phase transitions. From an exact solution of the model these phases can be classified according to the number of Majorana zero modes of an open chain: 0, 1, or 2 at each end. The model posseses a multicritical point where phases with 0, 1, and 2 Majorana end modes meet. The number of Majorana modes at each end of the chain is identical to the topological winding number of the Anderson's pseudospin vector that describes the BCS Hamiltonian. The topological classification of the phases requires a unitary time-reversal symmetry to be present. When this symmetry is broken, only the number of Majorana end modes modulo 2 can be used to distinguish two phases. In one of the regimes, the wave functions of the two phase shifted Majorana zero modes decays exponentially in space but but in an oscillatory manner. The wavelength of oscillation is identical to the asymptotic connected spin-spin correlation of the XY-model in a transverse field to which our model is dual.Comment: 11 pages, 8 figures; brief clarifying comments added; few new references; this version is accepted in Phys. Rev.

Software Piracy in the Presence of Open Source Alternatives

We develop a model to investigate the manner in which the pricing, profitability, and protection strategies of a seller of a proprietary digital good respond to changing market conditions. Specifically, we investigate how product piracy and the presence of open source software alternatives (such as Open Office) impact the optimal strategy of a seller of proprietary software (such as Microsoft Office). In contrast to previous literature, we show that firms may make more (rather than less) effort to control piracy when network externalities are strong. In addition, we show that the level of network externalities amplifies losses incurred by an incumbent due to high-quality pirated goods. Therefore, for products characterized by high network externalities (such as software), sellers need to try to maintain a large perceived quality gap between their product and illegal copies. Further, we demonstrate that the appearance of an OSS alternative leads the incumbent to reduce both price and the level of piracy control. Although high-quality pirated goods are detrimental to profits in the absence of OSS, they may actually limit the incumbent’s losses and the need to adjust price and protection strategies due to the introduction of an OSS alternative. Thus, an incumbent may find it easier to compete with OSS in the presence of product piracy. Finally, highly correlated intrinsic valuation between an incumbent and OSS products require smaller adjustments to price and piracy controls and leads to muted impact on incumbent profit