A delay logistic equation with variable growth rate

A logistic equation with distributed delay is considered in the case where the growth rate oscillates sinusoidally about a positive mean value. A delay kernel is chosen which admits bifurcation of the equilibrium state into a periodic solution when the growth rate is constant. It is shown that the fluctuations in growth rate modulate the bifurcation into a quasiperiodic solution. In certain circumstances, however, it is shown that frequency locking can occur but that this is a local phenomenon which does not persist outside the immediate vicinity of the bifurcation point

The Basics of International Trade: A Classroom Experiment

We introduce a simple web-based classroom experiment in which students learn the Ricardian model of international trade. Students are assigned to countries and then make individual production, trade and consumption decisions. The analysis of experimental data introduces students to the concepts of absolute and comparative advantage, relative prices, production possibility frontier, specialization, gains from trade, utility maximization and general equilibrium. Students learn about the relationship between individual decision-making and aggregate economic activity. The associated software, Ricardian Explorer, is easy to setup and requires minimal preparation time for instructors. The game is developed as a tool to complement courses in international trade, but it can be used in introductory and intermediate microeconomics courses as well. The analysis of teaching effectiveness has demonstrated that integration of this experiment in the curriculum enhances student learning.Absolute advantage, comparative advantage, specialization, production possibility frontier, gains from trade, utility maximization, general equilibrium, classroom experiments

Uber’s ‘partner-bosses’

Uber has long claimed it’s a technology company, not a transportation company, and an intermediary that connects supply (drivers) with demand (passengers). The language Uber uses communicates a strong message of distance between itself and its relationship to drivers: Uber classifies drivers as independent contractors, labels them “driver-partners”, and promotes them as entrepreneurs, although the company faces legal challenges over issues of worker misclassification. Uber relies on the politics of platforms to elude responsibility as a traditional employer, as well as regulatory regimes designed to govern traditional taxi businesses. The terminology Uber uses fosters a certain promise about the freedom of automated systems for organizing work that credits workers with a lot of autonomy and independence

Resonant interactions in B\'{e}nard-Marangoni convection in cylindrical containers

Convection in a cylindrical container of small aspect ratio is studied. It is known that when, in addition to buoyancy forces, thermocapillarity effects are taken into account, resonant interactions of two modes may appear. In the case of 1:2 resonance amplitude equations are derived, showing the existence of a stable heteroclinic orbit and rotating waves, until now not observed experimentally.Comment: 33 pages, latex, 14 figures, epsfig macro included. To appear in Physica

Surface-tension induced instabilities: Effects of lateral boundaries

Convection in circular and rectangular cylinders is analyzed. The governing equations and boundary conditions are formulated, linear and nonlinear stability theory are considered, and the physical implications of the theory are discussed

Lessons from Venezuela on Countering Oppression

Venezuela today is a dark microcosm of the promise of social change gone tragically awry. As a Venezuelan-American, witnessing the devastation of my country over the past two decades has shaped my views on movements that promise sweeping social transformation. It is primarily through the lens of this experience that I offer some reflections. Venezuela in the 1990s had a broken political system that excluded the vast majority of Venezuelan citizens from meaningful participation in political life and the benefits of national wealth creation. When Hugo Chávez re-entered the political scene in the late 1990s, after being released from prison for attempting a coup d’état in 1992, he tapped into a reservoir of resentment that had simmered over decades of exclusion and inequality

What Do We Expect from Our Friends?

We conduct a field experiment in a large real-world social network to examine how subjects expect to be treated by their friends and by strangers who make allocation decisions in modified dictator games. While recipients’ beliefs accurately account for the extent to which friends will choose more generous allocations than strangers (i.e. directed altruism), recipients are not able to anticipate individual differences in the baseline altruism of allocators (measured by giving to an unnamed recipient, which is predictive of generosity towards named recipients). Recipients who are direct friends with the allocator, or even recipients with many common friends, are no more accurate in recognizing intrinsically altruistic allocators. Recipient beliefs are significantly less accurate than the predictions of an econometrician who knows the allocator’s demographic characteristics and social distance, suggesting recipients do not have information on unobservable characteristics of the allocator.dictator games, beliefs, baseline altruism, directed altruism, social networks

Getting Closer or Drifting Apart

Advances in communication and transportation technologies have the potential to bring people closer together and create a "global village." However, they also allow heterogeneous agents to segregate along special interests, which gives rise to communities fragmented by type rather than by geography. We show that lower communication costs should always decrease separation between individual agents even as group-based separation increases. Each measure of separation is pertinent for distinct types of social interaction. A group-based measure captures the diversity of group preferences that can have an impact on the provision of public goods. While an individual measure correlates with the speed of information transmission through the social network that affects, for example, learning about job opportunities and new technologies. We test the model by looking at coauthoring between academic economists before and during the rise of the Internet in the 1990s.Economic

Why Beauty Matters

We decompose the beauty premium in an experimental labor market where “employers” determine wages of “workers” who perform a maze-solving task. This task requires a true skill which we show to be unaffected by physical attractiveness. We find a sizable beauty premium and can identify three transmission channels: (a) physically attractive workers are more confident and higher confidence increases wages; (b) for a given level of confidence, physically attractive workers are (wrongly) considered more able by employers; (c) controlling for worker confidence, physically attractive workers have oral skills (such as communication and social skills) that raise their wages when they interact with employers. Our methodology can be adopted to study the sources of discriminatory pay differentials in other settings.Economic