Self-selection patterns in Mexico-U.S. migration: the role of migration networks

This paper examines the role of migration networks in determining self-selection patterns of Mexico-U.S. migration. We first present a simple theoretical framework showing how such networks impact on migration incentives at different education levels and, consequently, how they are likely to affect the expected skill composition of migration. Using survey data from Mexico, we then show that the probability of migration is increasing with education in communities with low migrant networks, but decreasing with education in communities with high migrant networks. This is consistent with positive self-selection of migrants being driven by high migration costs, as advocated by Chiquiar and Hanson (2005), and with negative self-selection of migrants being driven by lower returns to education in the U.S. than in Mexico, as advocated by Borjas (1987)

Can migration reduce educational attainments? depressing evidence from Mexico

This paper examines the impact of migration on educational attainments in rural Mexico. Using historical migration rates by state to instrument for current migration, we find evidence of a significant negative effect of migration on schooling attendance and attainments of 12 to 18 year-old boys and of 16 to 18 year-old girls. IV-Censored Ordered Probit results show that living in a migrant household lowers the chances of boys completing junior high-school and of boys and girls completing high-school. The negative effect of migration on schooling is somewhat mitigated for younger girls with low educated mothers, which is consistent with remittances relaxing credit constraints on education investment for the very poor. However, for the majority of rural Mexican children, family migration depresses educational attainment. Comparison of the marginal effects of migration on school attendance and on participation to other activities shows that the observed decrease in schooling of 16 to 18 year olds is accounted for by current migration of boys and increases in housework for girls

New players in the preventive treatment of migraine.

Migraine is a common, chronic disorder of the brain causing much disability, as well as personal, familial and societal impact. Several oral preventive agents are available in different countries for the prevention of migraine, but none have performed better than 50% improvement in 50% of patients in a clinical trial. Additionally, each has various possible adverse events making their tolerability less than optimal. Recently, three monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) ligand (LY2951742, ALD403 and TEV-48125) and one targeting the CGRP receptor (AMG 334) have completed phase 2 trials, and the results have been reported. These early results show them all to be somewhat more effective than placebo, with no serious adverse events. Three have been studied for episodic migraine, and only TEV-48125 has been studied for both high frequency episodic and chronic migraine. Moreover, preliminary data suggests that neurostimulation is effective in migraine treatment, including stimulation of the sphenopalatine ganglion, transcutaneous supraorbital and supratrochlear nerve, and transcutaneous vagus nerve. In this article, these innovative therapies will be reviewed

Alzheimers: The Disease of the Century

Alzheimer's disease is the major cause of dementia in the United States, with spending in the range of $100 billion annually. It affects 5 to 7 percent of people over 65 years of age and 20 to 40 percent over 80, and is estimated to be the fourth to fifth most common cause of death in the United States. Concerted research efforts in the clinical and basic neurosciences in the last 30 years have resulted in marked advances in our understanding of the clinical course and mechanisms of Alzheimer's disease as well as new therapeutic directions. This review provides a short history of the progress that has been made in Alzheimer's disease research during this time, and identifies some of the seminal discoveries and insights that contributed to this progress

Virtuous Billing

Aristotle tells us, in his Nicomachean Ethics, that we become ethical by building good habits and we become unethical by building bad habits: “excellence of character results from habit, whence it has acquired its name (êthikê) by a slight modification of the word ethos (habit).” Excellence of character comes from following the right habits. Thinking of ethics as habit-forming may sound unusual to the modern mind, but not to Aristotle or the medieval thinkers who grew up in his long shadow. “Habit” in Greek is “ethos,” from which we get our modern word, “ethical.” In Latin, habits are moralis, which gives us the word, “moral.” Aristotle explains that we cannot alter nature by practice: we cannot teach or train a rock to roll up a hill no matter how often we throw it up. But we can alter ourselves by practice. We can train ourselves to be ethical by practice, just as we learn to play the harp by practice.It is a timeless adage that when analyzing the unacceptable behavior of others, one should never attribute to malice that which can be adequately explained by stupidity.This essay applies classics ethics analysis and social science principles to ask whether we can find ways to improve billing behavior in law firms

Voting rules in sequential search by committees: theory and experiments

We propose a committee extension of the individual sequential search model called the “secretary problem,” where collective decisions on when to stop the search are reached via a pre-specified voting rule. We offer a game-theoretic analysis of our model, and then report two experiments on three-person committees with either uncorrelated or perfectly correlated preferences under three different voting rules, followed by a third experiment on single decision makers. Relative to equilibrium predictions, committees with uncorrelated preferences over-searched under minority and majority voting rules, but otherwise under-searched or approximated equilibrium play. Individually, committee members were often less strategic when their preferences were uncorrelated than when they were perfectly correlated. Collectively, committees’ decisions were more strategic than single decision makers’ only under the unanimity rule, though still not significantly better in terms of the decision makers’ welfare. Finally, across our experiments that involved committee search, the unanimity rule always optimized committee welfare

Networking Effects on Cooperation in Evolutionary Snowdrift Game

The effects of networking on the extent of cooperation emerging in a competitive setting are studied. The evolutionary snowdrift game, which represents a realistic alternative to the well-known Prisoner's Dilemma, is studied in the Watts-Strogatz network that spans the regular, small-world, and random networks through random re-wiring. Over a wide range of payoffs, a re-wired network is found to suppress cooperation when compared with a well-mixed or fully connected system. Two extinction payoffs, that characterize the emergence of a homogeneous steady state, are identified. It is found that, unlike in the Prisoner's Dilemma, the standard deviation of the degree distribution is the dominant network property that governs the extinction payoffs.Comment: Changed conten