The Relationship between the Beveridge-Nelson Decomposition andUnobserved Component Models with Correlated Shocks

Many researchers believe that the Beveridge-Nelson decomposition leads to permanent and transitory components whose shocks are perfectly negatively correlated. Indeed, some even consider it to be a property of the decomposition. We demonstrate that the Beveridge-Nelson decomposition does not provide definitive information about the correlation between permanent and transitory shocks in an unobserved components model. Given an ARIMA model describing the evolution of U.S. real GDP, we show that there are many state space representations that generate the Beveridge-Nelson decomposition. These include unobserved components models with perfectly correlated shocks and partially correlated shocks. In our applications, the only knowledge we have about the correlation is that it lies in a restricted interval that does not include zero. Although the filtered estimates of the trend and cycle are identical for models with different correlations, the observationally equivalent unobserved components models produce different smoothed estimates.

Coisotropic Branes, Noncommutativity, and the Mirror Correspondence

We study coisotropic A-branes in the sigma model on a four-torus by explicitly constructing examples. We find that morphisms between coisotropic branes can be equated with a fundamental representation of the noncommutatively deformed algebra of functions on the intersection. The noncommutativity parameter is expressed in terms of the bundles on the branes. We conjecture these findings hold in general. To check mirror symmetry, we verify that the dimensions of morphism spaces are equal to the corresponding dimensions of morphisms between mirror objects.Comment: 13 page

An Overview and Examination of the Indian Services Sector

India’s service sector has grown rapidly since the 1990s. Domestic demand for services has increased as incomes have risen, triggering the expansion of industries such as banking, education, and telecommunications. Exports have also increased rapidly, led by information technology and business process outsourcing (IT-BPO). India’s ability to offer low-cost, high-quality IT-BPO services has made it a world leader in this industry. However, employment in services has not grown as quickly as output. The majority of India’s jobseekers are low-skilled, but demand for workers is growing fastest in higher-skill industries. The supply of highly-skilled workers has not kept pace with demand, causing wages to increase faster for these workers than for lower-skilled ones. India’s government has supported the growth of service industries through a mix of deregulation, liberalization, and incentive programs, such as the Software Technology Parks of India. Nevertheless, burdensome regulations, poor infrastructure, and foreign investment restrictions continue to affect service firms’ ability to do business. USITC analysis suggests that additional liberalization would lead to an increase in India’s imports of services

One-Sided Competition in Two-Sided Social Platform Markets? An Organizational Ecology Perspective

Similar to love, competition can often be unrequited. This study explores the asymmetric pattern of competition driven by membership overlap in two-sided mobile social apps (MSAs) markets. Building on the niche-width dynamics framework, we theorize and validate the relative prevalence and survival capabilities of messaging apps and SNS apps, especially when membership overlap fosters current or potential competition between the two app categories. The analyses—based on panel dataset consisting of information on 8,483 panel members’ exact amount of time used for 21 mobile social apps—show that competition between SNS and messaging apps can be asymmetric in favor of messaging apps. This asymmetric pattern is more pronounced for membership-based competition compared to usage-based competition. In addition, different MSAs developed by same platform providers exhibit synergistic effects, rather than destructive consequences, on each other’s growth. The findings identify the complex nature of competition within-category and between-category competition in MSAs markets

A Profiling Model for Readmission of Patients with Congestive Heart Failure: A multi-hospital study

Mitigating preventable readmissions, where patients are readmitted for the same primary diagnosis within thirty days, is a significant challenge in delivery of high quality healthcare. Towards this end, it is imperative to understand the cause, risk propensity and timing associated with patient readmissions. This study develops a patient profiling model that can predict the propensity of readmission for a patient as well as the timing of future readmissions. We develop a new model termed as BG/EG Hurdle model that can simultaneously estimate both the propensity and timing of patient readmissions. We test this model using a unique dataset that tracks both patient demographic and clinical data for individual patients across 72 hospitals in North Texas. The results indicate that patient profiles derived from our model can serve as the building block for clinical decision support system to identify patients with high CHF readmission risk

Nature or Nurture? An Analysis of Rational Addiction to Mobile Social Applications

Through the lens of rational addiction theory (Becker and Murphy, 1988), this study investigates whether addiction to mobile social apps should be viewed as a rational behavior rather than an uncontrollable, irrational disorder. To derive the analytical model, this study extends the rational addiction framework to include a utility-level network effect as the key factor that regulates the inter-temporal consumption of mobile social apps. Further, to validate empirically the rational addiction model in this context, we gathered and analyzed longitudinal panel data on the weekly app usage of thousands of smartphone users. The findings suggest that consistent with the rational addiction theory, users of mobile social apps are rational and forward-looking. They determine their current consumption based on both past and future consumption and the utility derived from network effects. However, the extent of rational addiction to mobile social apps varies considerably across diverse demographic groups and app categories