Assortative Matching and the Education Gap

This paper attempts to explain the decrease and reversal of the education gap between males and females. Given a continuum of agents, the education decisions are modelled as an assignment game with endogenous types. In the first stage agents choose their education level and in the second they participate in the labor and marriage markets. Competition among potential matches ensures that the efficient education levels can always be sustained in equilibrium, but there may be inefficient equilibria. Combining asymmetries intrinsic to the modelled markets the model reproduces the observed education gap.Assortative matching, pre-marital investments, efficiency

The impossibility of strategy-proof clustering

Clustering methods group individuals or objects based on information about their similarity or proximity. When the raw information to generate clusters cannot be easily observed or verified, the cluster designer must rely on information reported by individuals behind the observations. When these individuals receive utility from a public decision taken with aggregated data within each own's cluster and have single-peaked preferences, we prove that there do not exist clustering methods such that truth-revealing behavior is always a dominant strategyclustering methods

The impact of export-oriented entrepreneurship on regional economic growth

Although export-oriented new ventures and the field of international entrepreneurship have received considerable attention by scholars during the last decade (Oviatt and McDougla, 2005), their potential economic impact has not been sufficiently analyzed yet. To the best of our knowledge, no studies on this issue have been carried out at regional level. Despite the increasing impact of globalization, regions have emerged as the essential and active unit of economic development process (Scott and Stopper, 2003). Regions are influential environments fostering entrepreneurship (Feldman, 2000). This is especially true for knowledge-based entrepreneurship since proximity to knowledge sources matters in order to discover opportunities and exploit them (Audretsch, 1998). Moreover, regions differ culturally and economically, and such differences encourage or discourage people to venture in entrepreneurial activity. We analyze the impact of export-oriented entrepreneurship on regional growth using data provided by the Global Entrepreneurship Monitor project and the Spanish Institute of Statistics, for 17 NUTS-2 Spanish regions over a period of six years. After controlling for catching-up effects (van Stel et al., 2005), as well as, other drivers of economic growth (e.g. change in technology capability and human capital), we found evidence that those regions with a higher percentage of adult population involved in export-oriented entrepreneurship experience a higher GDP growth. This relationship is greater as the level of foreign customers served by the entrepreneurial initiatives is substantially higher (i.e., at least 1%, 25% or 75% of customers located abroad). These results support those found at national level by Hessels and van Stel (2009). However, our paper adds to the extant literature on entrepreneurship by analyzing the role of entrepreneurial activity with different levels of export intensity on regional growth under a longitudinal context. Policy implications derived from these results suggest that trade policies for export promotion among new ventures should be carried out at regional level. Otherwise, exporting new ventures may concentrate only on certain regions, which would help to increase differences on growth within a nation.

Downward Adjustments in a Cyclical Environment: The Case of Chilean Pelagic Fisheries

This paper offers an empirical analysis of harvest functions for the two main Chilean pelagic fisheries, which are characterized by cyclical fish abundance. Two main results are obtained. First, we identify production-side effects that weaken the incentives to adjust towards lower fishing efforts: (i) increasing returns in the use of variable inputs are observed, which are strengthened by external economies associated to aggregate search effort for fish; and (ii) catch yields sensitive to changes in abundance, but where the strength of this effect decreases as abundance declines. Second, we confirm the empirical relevance of Translog harvest technologies. This contradicts a frequent practice in bio-economic models, i.e. considering harvest-input elasticities as being constant and independent from the scale of production.Chilean pelagic fisheries; harvest functions; panel estimation; fishing cycles.

Major League Baseball Draft Pick Compensation: How To Evaluate The Marginal Revenue Product Of Labor Of Drafted Players

The Major League Baseball draft is virtually the only means by which US and US territory born players have access to becoming major league baseball players. As a condition of their initial contracts, players are subjected to initial contract terms, that limit their traditional free market ability to earn a salary commensurate with their actual worth. This research attempts to quantify the difference between what players would earn on the open market, as free agents, and what they earn by being controlled by baseball’s reserve clause, by analyzing the current compensation system established by Major League Baseball, how drafted players have limited leverage in negotiations, and whether their compensation approximates actual provided value. The result of this analysis is clear that players on their initial contracts over perform relative to their compensation, relative to players who signed open-market contracts

Ascending midbrain dopaminergic axons require descending GAD65 axon fascicles for normal pathfinding

The Nigrostriatal pathway (NSP) is formed by dopaminergic axons that project from the ventral midbrain to the dorsolateral striatum as part of the medial forebrain bundle. Previous studies have implicated chemotropic proteins in the formation of the NSP during development but little is known of the role of substrate-anchored signals in this process. We observed in mouse and rat embryos that midbrain dopaminergic axons ascend in close apposition to descending GAD65-positive axon bundles throughout their trajectory to the striatum. To test whether such interaction is important for dopaminergic axon pathfinding, we analyzed transgenic mouse embryos in which the GAD65 axon bundle was reduced by the conditional expression of the diphtheria toxin. In these embryos we observed dopaminergic misprojection into the hypothalamic region and abnormal projection in the striatum. In addition, analysis of Robo1/2 and Slit1/2 knockout embryos revealed that the previously described dopaminergic misprojection in these embryos is accompanied by severe alterations in the GAD65 axon scaffold. Additional studies with cultured dopaminergic neurons and whole embryos suggest that NCAM and Robo proteins are involved in the interaction of GAD65 and dopaminergic axons. These results indicate that the fasciculation between descending GAD65 axon bundles and ascending dopaminergic axons is required for the stereotypical NSP formation during brain development and that known guidance cues may determine this projection indirectly by instructing the pathfinding of the axons that are part of the GAD65 axon scaffold

The orientation and kinematics of inner tidal tails around dwarf galaxies orbiting the Milky Way

Using high-resolution collisionless N-body simulations we study the properties of tidal tails formed in the immediate vicinity of a two-component dwarf galaxy evolving in a static potential of the Milky Way (MW). The stellar component of the dwarf is initially in the form of a disk and the galaxy is placed on an eccentric orbit motivated by CDM-based cosmological simulations. We measure the orientation, density and velocity distribution of the stars in the tails. Due to the geometry of the orbit, in the vicinity of the dwarf, where the tails are densest and therefore most likely to be detectable, they are typically oriented towards the MW and not along the orbit. We report on an interesting phenomenon of `tidal tail flipping': on the way from the pericentre to the apocentre the old tails following the orbit are dissolved and new ones pointing towards the MW are formed over a short timescale. We also find a tight linear relation between the velocity of stars in the tidal tails and their distance from the dwarf. Using mock data sets we demonstrate that if dwarf spheroidal (dSph) galaxies in the vicinity of the MW are tidally affected their kinematic samples are very likely contaminated by tidally stripped stars which tend to artificially inflate the measured velocity dispersion. The effect is stronger for dwarfs on their way from the peri- to the apocentre due to the formation of new tidal tails after pericentre. Realistic mass estimates of dSph galaxies thus require removal of these stars from kinematic samples.Comment: 8 pages, 7 figures, accepted for publication in MNRA

EL ESQUEMA DE LA PIRíMIDE

Los esquemas piramidales son ilegales en muchos paí­ses; sin embargo, las gentes que los imponen logran conseguir incautos para sus fines. El artí­culo hace un análisis de este fenómeno y de su incidencia en las economí­as personales de quienes caen en este tipo de estafas. Hace unr ecuento de hechos que han sucedido en otros paí­ses y,en especial, en Colombia.El artí­culo fue escrito por la Consejera General de la Comisión Federal de Comercio de los Estados Unidos

The role of sense of effort on self-selected cycling power output

PURPOSE: We explored the effects of the sense of effort and accompanying perceptions of peripheral discomfort on self-selected cycle power output under two different inspired O2 fractions. METHODS: On separate days, eight trained males cycled for 5 min at a constant subjective effort (sense of effort of '3' on a modified Borg CR10 scale), immediately followed by five 4-s progressive submaximal (sense of effort of "4, 5, 6, 7, and 8"; 40 s between bouts) and two 4-s maximal (sense of effort of "10"; 3 min between bouts) bouts under normoxia (NM: fraction of inspired O2 [FiO2] 0.21) and hypoxia (HY: [FiO2] 0.13). Physiological (Heart Rate, arterial oxygen saturation (SpO2) and quadriceps Root Mean Square (RMS) electromyographical activity) and perceptual responses (overall peripheral discomfort, difficulty breathing and limb discomfort) were recorded. RESULTS: Power output and normalized quadriceps RMS activity were not different between conditions during any exercise bout (p > 0.05) and remained unchanged across time during the constant-effort cycling. SpO2 was lower, while heart rate and ratings of perceived difficulty breathing were higher under HY, compared to NM, at all time points (p < 0.05). During the constant-effort cycling, heart rate, overall perceived discomfort, difficulty breathing and limb discomfort increased with time (all p < 0.05). All variables (except SpO2) increased along with sense of effort during the brief progressive cycling bouts (all p < 0.05). During the two maximal cycling bouts, ratings of overall peripheral discomfort displayed an interaction between time and condition with ratings higher in the second bout under HY vs. NM conditions. CONCLUSION: During self-selected, constant-effort and brief progressive, sub-maximal, and maximal cycling bouts, mechanical work is regulated in parallel to the sense of effort, independently from peripheral sensations of discomfort

A Rockefeller Foundation Health Primer for US-Occupied Nicaragua, 1914–1928

The article presents views from above and below of the Rockefeller Foundation's International Health Commission's (IHC's) hookworm control program in Nicaragua from 1914 to 1928. It looks at the meaning, impact, and unique configuration of the Nicaraguan mission, while taking into account the larger global institutional project of this important international health actor. Although the IHC program in Nicaragua complemented some of the social policy goals of the US intervention in Nicaragua, which was a de facto protectorate during this period, the institution cannot be considered a direct expression or agent of US foreign policy. Ultimately the shape and limits of the iHC mission to Nicaragua were determined by the institutional project of the international public health agency itself, and by local considerations ranging from the characteristics of the staff to the response of rural communities to the anti-hook-worm campaigns