The effect of binge-watching on the subscription of video on demand: results from randomized experiments

We analyze the outcomes of two randomized field experiments to study the effect of binge-watching on subscription to video on demand. In both cases, we offered access to subscription VoD (SVoD) to a random set of households for several weeks and used another random set of households as a control group. In both cases, we find that the households that binge-watch TV shows are less likely to pay for SVoD after these free trials. Our results suggest that binge-watchers deplete the content of interest to them very quickly, which reduces their short-term willingness to pay for SVoD. We also show that recommendation reminders aimed at widening the content preferences of households offset the negative effect of binge-watching and lessen the concerns of binge-watchers with lack of content refresh. We discuss that these recommendation reminders may help content providers manage supply costs, which may otherwise become prohibitive with frequent updates to SVoD catalogs.info:eu-repo/semantics/publishedVersio

Cell cycle and checkpoint regulation of the budding yeast S-phase promoting factor Dbf4p

The Dbf4/Cdc7 protein kinase is essential for origin firing during S phase in the budding yeast Saccharomyces cerevisiae. The catalytic subunit, Cdc7p, is present at constant levels throughout the cell cycle despite its kinase activity being periodic. Cdc7p kinase requires association with Dbf4p, the regulatory subunit, for its activation. This study shows that Dbf4 protein levels are periodic during the cell cycle. Dbf4p is absent from early G1 cells, appears in late G1 and accumulates during S and G2 phases. This pattern of expression resembles the periodicity of the Cdc7p kinase activity. Dbf4p is rapidly degraded at the onset of anaphase in mitosis and remains highly unstable in pre-START G1 phase. The rapid degradation of Dbf4p requires the function of the Anaphase Promoting Complex (APC). Dbf4p contains a destruction box sequence in its N-terminus, that when mutated, eliminates this APC dependent degradation. Conditions that block the elongation step of DNA replication prevent the activation of late origins of replication in a MEC1/RAD53 dependent manner. During such a block, CDC7 cannot execute its function at late replicating origins. In this study, it was observed that Dbf4p is phosphorylated in response to blocks to S phase progression. Phosphorylation of Dbf4p is dependent upon Rad53p and Cdc7 protein kinases both in vivo and in vitro. Although phosphorylated Dbf4/Cdc7p retains its kinase activity during the S phase block, its ability to associate with chromatin is inhibited. A model is suggested whereby in response to blocks to S phase progression, activation of the Mec1p/Rad53p checkpoint pathway results in the phosphorylation of Dbf4p. This phosphorylated form would no longer be able to associate with origins of replication, thereby preventing Cdc7p from activating late origins of replication

Peer influence in the diffusion of iPhone 3G over a large social network

In this paper, we study the effect of peer influence in the diffusion of the iPhone 3G across a number of communities sampled from a large dataset provided by a major European Mobile carrier in one country. We identify tight communities of users in which peer influence may play a role and use instrumental variables to control for potential correlation between unobserved subscriber heterogeneity and friends' adoption. We provide evidence that the propensity of a subscriber to adopt increases with the percentage of friends who have already adopted. During a period of 11 months, we estimate that 14 percent of iPhone 3Gs sold by this carrier were due to peer influence. This result is obtained after controlling for social clustering, gender, previous adoption of mobile Internet data plans, ownership of technologically advanced handsets, and heterogeneity in the regions where subscribers move during the day and spend most of their evenings. This result remains qualitatively unchanged when we control for changes over time in the structure of the social network. We provide results from several policy experiments showing that, with this level of effect of peer influence, the carrier would have hardly benefitted from using traditional marketing strategies to seed the iPhone 3G to benefit from viral marketing.info:eu-repo/semantics/publishedVersio

Controlling digital piracy via domain name system blocks: a natural experiment

We study the impact of batch DNS filtering of copyright-infringing websites, a novel administrative-based process that does not require judicial involvement. In partnership with a large telecommunication provider, we measure the impact of this intervention on piracy activity and the legal alternatives integrated into households' media subscription bundles, an aspect largely unexplored in prior literature. We find a significant reduction in Internet traffic, which proxies piracy activity. However, we do not observe statistically significant changes in the consumption of the legal alternatives under consideration, only a slight increase in TV viewership. To further understand these outcomes, we examine the heterogeneity of these results based on households' pre-block usage intensity of digital piracy and demographic characteristics. Our work contributes to the literature on the effectiveness of piracy control strategies and informs policy makers and industry practitioners about the benefits and limitations of DNS-based website blocking.info:eu-repo/semantics/publishedVersio

The effect of friends’ churn on consumer behavior in mobile networks

We study how consumers decide which tariff plan to choose and whether to churn when their friends churn in the mobile industry. We develop a theoretical model showing conditions under which users remain with their carrier and conditions under which they churn when their friends do. We then use a large and rich anonymized longitudinal panel of call detailed records to characterize the consumers’ path to death with unprecedented level of detail. We explore the structure of the network inferred from these data to derive instruments for friends’ churn, which is typically endogenous in network settings. This allows us to econometrically identify the effect of peer influence in our setting. On average, we find that each additional friend that churns increases the monthly churn rate by 0.06 percent. The observed monthly churn rate across our dataset is 2.15 percent. We also find that firms introducing the pre-paid tariff plans that charge the same price to call users inside and outside the carrier help retain consumers that would otherwise churn. In our setting, without this tariff plan the monthly churn rate could have been as high as 8.09 percent. We perform a number of robustness checks, in particular to how we define friends in the social graph, and show that our results remain unchanged. Our paper shows that the traditional definition of customer lifetime value underestimates the value of consumers and, in particular, that of consumers with more friends due to the effect of contagious churn and, therefore, managers should actively take into account the structure of the social network when prioritizing whom to target during retention campaigns.info:eu-repo/semantics/acceptedVersio

Target the ego or target the group: evidence from a randomized experiment in proactive churn management

We propose a new strategy for proactive churn management that actively uses social network information to help retain consumers. We collaborate with a major telecommunications provider to design, deploy, and analyze the outcomes of a randomized control trial at the household level to evaluate the effectiveness of this strategy. A random subset of likely churners were selected to be called by the firm. We also randomly selected whether their friends would be called. We find that listing likely churners to be called reduced their propensity to churn by 1.9 percentage points from a baseline of 17.2%. When their friends were also listed to be called, their likelihood of churn reduced an additional 1.3 percentage points. The client lifetime value of likely churners increased 2.1% with traditional proactive churn management, and this statistic becomes 6.4% when their friends were also listed to be called by the firm. We show that, in our setting, likely churners receive a signal from their friends that reduces churn among the former. We also discuss how this signal may trigger mechanisms akin to both financial comparisons and conformity that may explain our findings.info:eu-repo/semantics/acceptedVersio

The effect of subscription video-on-demand on piracy: evidence from a household-level randomized experiment

We partner with a major multinational telecommunications provider to analyze the effect of subscription video-on-demand (SVoD) services on digital piracy. For a period of 45 consecutive days, a group of randomly selected households who used BitTorrent in the past were gifted with a bundle of TV channels with movies and TV shows that could be streamed as in SVoD. We find that, on average, households that received the gift increased overall TV consumption by 4.6% and reduced Internet downloads and uploads by 4.2% and 4.5%, respectively. However, and also on average, treated households did not change their likelihood of using BitTorrent during the experiment. Our findings are heterogeneous across households and are mediated by the fit between the preferences of households in our sample for movies and the content available as part of the gifted channels. Households with preferences aligned with the gifted content reduced their probability of using BitTorrent during the experiment by 18% and decreased their amount of upload traffic by 45%. We also show using simulation that the size of the SVoD catalog and licensing window restrictions limit significantly the ability of content providers to match SVoD offerings to the preferences of BitTorrent users. Finally, we estimate that households in our sample are willing to pay at most $3.25 USD per month to access a SVoD catalog as large as Netflix's in the United States. Together, our results show that, as a stand-alone strategy, using legal SVoD to curtail piracy will require, at the minimum, offering content much earlier and at much lower prices than those currently offered in the marketplace, changes that are likely to reduce industry revenue and that may damage overall incentives to produce new content while, at the same time, curbing only a small share of piracy.info:eu-repo/semantics/acceptedVersio

The effect of shortening lock-in periods in telecommunication services

In this research note, we study the welfare implications of shortening the length of the lock-in period associated with triple play contracts using household level data, from a large telecommunications provider, for a period of 6 months. Using a multinomial logit model to explain consumer behavior we show that, in our setting, shortening the length of the lock-in period decreases the aggregated profit of the firms in the market more than it increases consumer surplus. This result arises because shortening the length of the lock-in period increases churn, and the costs to set up service for the consumers that churn and join a new carrier supersede the increase in the consumers' willingness to pay for service when the length of the lock-in period shortens.info:eu-repo/semantics/publishedVersio

Genome architecture is a selectable trait that can be maintained by antagonistic pleiotropy

Chromosomal rearrangements are mutations contributing to both within and between species variation; however their contribution to fitness is yet to be measured. Here we show that chromosomal rearrangements are pervasive in natural isolates of Schizosaccharomyces pombe and contribute to reproductive isolation. To determine the fitness effects of chromosome structure, we constructed two inversions and eight translocations without changing the coding sequence. We show that chromosomal rearrangements contribute to both reproductive success in meiosis and growth rate in mitosis with a strong genotype by environment interaction. These changes are accompanied by alterations in gene expression. Strikingly, we find several examples leading to antagonistic pleiotropy. Even though chromosomal rearrangements may have a deleterious effect during sexual reproduction, some compensate with a strong growth advantage in mitosis. Our results constitute the first quantification of fitness effects caused by de novo mutations that result in chromosomal rearrangement variation and suggest a mechanism for their maintenance in natural populations.FCT PhD and Postdoctoral fellowships

Telomeres in aging and disease: lessons from zebrafish

Age is the highest risk factor for some of the most prevalent human diseases, including cancer. Telomere shortening is thought to play a central role in the aging process in humans. The link between telomeres and aging is highlighted by the fact that genetic diseases causing telomerase deficiency are associated with premature aging and increased risk of cancer. For the last two decades, this link has been mostly investigated using mice that have long telomeres. However, zebrafish has recently emerged as a powerful and complementary model system to study telomere biology. Zebrafish possess human-like short telomeres that progressively decline with age, reaching lengths in old age that are observed when telomerase is mutated. The extensive characterization of its well-conserved molecular and cellular physiology makes this vertebrate an excellent model to unravel the underlying relationship between telomere shortening, tissue regeneration, aging and disease. In this Review, we explore the advantages of using zebrafish in telomere research and discuss the primary discoveries made in this model that have contributed to expanding our knowledge of how telomere attrition contributes to cellular senescence, organ dysfunction and disease.Fundação para a Ciência e Tecnologia grant: (PTDC/BIM-ONC/3402/2014); Howard Hughes Medical Institute