World\u27s Fairs in Chicago and Barcelona: Spectacle, Memory, and Nationalism

Nineteenth-century international exhibitions served as platforms for national competition and self-expression. Though over 4,000 miles apart, both Chicago, Illinois and Barcelona, Spain were animated by second city politics and featured a thriving industrial economy in the last decades of the nineteenth century. Yet while Chicagoans swelled with pride about the city they had helped resurrect from the ashes of the Great Chicago Fire of 1871, they also displayed patriotism toward an American nation that had overcome the Civil War and was rapidly amassing power. A burgeoning Catalan nationalist movement, on the other hand, contributed to a widening disconnect between the capital of Catalonia and a sputtering Spanish nation. These pivotal differences - along with historical circumstance - have informed the historical interpretation of Chicago\u27s 1893 World\u27s Columbian Exposition and Barcelona\u27s 1888 Universal Exposition. The ways in which the collective memory of these two world\u27s fairs have diverged shed light on why, today, remembering Chicago\u27s World\u27s Fair has largely become an intellectual exercise while conjuring up memories of Barcelona\u27s Universal Exposition persists as a critical tool for Catalan nationalists wishing to advance their interests and broadcast their nationalism to the global community

It´s Not My Money: An Experiment on Risk Aversion and the House-money Effect

The house-money effect -people´s tendency to be more daring with easily-gotten money- is abehavioral pattern that poses questions about the external validity of experiments in economics: to what extent do people behave in experiments like they would have in a real-life situation, given that they play with easily-gotten house money? We ran an economic experiment with 66 students to measure the house-money effect on their risk preferences. They received an amount of money with which they made risky decisions involving losses and gains; a treatment group got the money 21 days in advance and a control group got it the day of the experiment. We find that, when facing possible losses, people in the treatment group showed a lower tolerance to risk than people in the control group. If the players are assumed to have a CRRA utility function and to behave according to expected-utility theory, the risk-attitude adjustment corresponds to an average increase of 1 in their risk aversion coefficient. While the exact pattern of this house-money adjustment differs by gender, it is not possible to determine the sign of this gender effect unambiguously. In any case, it is advisable to include credible controls for the house-money effect in experimental work in economics.House-money effect, risk aversion, prospect theory, economic experiment, external validity.

Essays on Development Economics

This dissertation contains three essays in Development Economics. The first two chapters relate to the provision of credit for agricultural production in a developing country. The third chapter explores methodological issues in the measurement of risk aversion using laboratory experiments. Risk aversion has been suggested as a theoretical explanation for credit constraints in agricultural settings in developing countries. Better measures of risk aversion can be used to empirically validate these theories. In Chapter 1 of this dissertation, I study the consequences of the use of credit scoring systems for agricultural lending in developing countries. Credit scoring has become a widespread tool to assess the creditworthiness of prospective borrowers, and has been found to increase efficiency and welfare in many settings. This chapter identifies a shortcoming in existing credit scoring systems that may lead to a market failure in agricultural lending in developing countries: Farmers' scores -- and their access to credit -- decline because of exogenous short-term weather shocks that do not reduce their likelihood of future repayment. I use data on the near universe of formal agricultural loans for coffee production in Colombia to show that excess rainfall shocks cause lower concurrent loan repayment, lower credit scores, and more frequent denial of subsequent loan applications. Then, I draw on the agronomic literature on coffee production and use survey data to show that productivity, income and repayment behavior recover faster from these shocks than farmers' credit histories. In the chapter I argue that these additional loan denials create costs for both farmers and the lender that could be avoided. The results presented in this chapter suggest that incorporating verifiable information on individual level shocks into credit scores would increase the efficiency of credit markets. In Chapter 2, together with Jairo Esquivel, Margarita Gáfaro, Guillermo Otero and Moisés Mahecha, I study the determinants of repayment of loans to a public development bank. In particular, we investigate whether the public nature of a lender affects the repayment behavior of its borrowers. We conducted a field experiment where customers who receive reminder phone calls before a payment installment of loans were randomly assigned to different phone call scripts. The loans are from a public agricultural bank in Colombia. In our main treatment, we include a sentence to remind the customer of the public nature of the lender. We find strong and positive effects on repayment performance: farmers in this treatment have probabilities of ever being overdue and of entering into a period of 30 days past due that are respectively 10\% and 22\% lower than those of farmers treated with the traditional script. We interpret this finding as evidence that farmers are more like to repay their loans because of the public nature of the bank. Results from heterogeneity exercises show that some measures of state presence increase the magnitude of the effect of the public treatment, which suggests that state deterrence is a potential mechanism behind our findings. Furthermore, results from treatments where sentiments of altruism and peer pressure are induced by the script suggest that these motives explain part of the effect that the public nature of the lender has on repayment. In Chapter 3, together with Juan Camilo Cárdenas, Christian Jaramillo and Luis Roberto Martínez, I address a methodological concern common in laboratory experiments. The house-money effect, understood as a person's tendency to be more daring with easily-gotten money, is a behavioral pattern that poses questions about the external validity of experiments in economics. We ran an economic experiment with 122 students, who received an amount of money with which they made risky decisions involving losses and gains; a randomly selected treatment group received the money 21 days in advance and a control group got it the day of the experiment. With our preferred specification, we find a mean CRRA risk aversion coefficient of 0.34, with a standard deviation of 0.09. Furthermore, if subjects in the treatment group spent 35\% of the endowment (as they did, on average) their CRRA risk aversion coefficient is higher than that of the control group by approximately 0.3 standard deviations. We interpret this result as evidence of a small and indirect house money effect operating though the amount of the cash in advance that was actually spent. We conclude in this chapter that the house money effect may play a small role in decisions under uncertainty, especially when involving losses

Genetics of Isolated Hypogonadotropic Hypogonadism: Role of GnRH Receptor and Other Genes

Hypothalamic gonadotropin releasing hormone (GnRH) is a key player in normal puberty and sexual development and function. Genetic causes of isolated hypogonadotropic hypogonadism (IHH) have been identified during the recent years affecting the synthesis, secretion, or action of GnRH. Developmental defects of GnRH neurons and the olfactory bulb are associated with hyposmia, rarely associated with the clinical phenotypes of synkinesia, cleft palate, ear anomalies, or choanal atresia, and may be due to mutations of KAL1, FGFR1/FGF8, PROKR2/PROK2, or CHD7. Impaired GnRH secretion in normosmic patients with IHH may be caused by deficient hypothalamic GPR54/KISS1, TACR3/TAC3, and leptinR/leptin signalling or mutations within the GNRH1 gene itself. Normosmic IHH is predominantly caused by inactivating mutations in the pituitary GnRH receptor inducing GnRH resistance, while mutations of the β-subunits of LH or FSH are very rare. Inheritance of GnRH deficiency may be oligogenic, explaining variable phenotypes. Future research should identify additional genes involved in the complex network of normal and disturbed puberty and reproduction

Interhypothalamic adhesion and multiple cerebral abnormalities in a 2-year-old boy.

International audienceInterhypothalamic adhesion (IHA) is a band of tissue spanning the anterior recess of the third ventricle, linear in the transverse and frontal planes. Recently described, in 2008 [1] in a patient with a Chiari type II malformation, IHA is commonly associated with multiple congenital anomalies [2] particularly midline disorders but can also be isolated. IHA is related with hypothalamo-pituitary dysfunctions and seizures in most of patient, but asymptomatic patients have been reported [3]. Here, we present a case of IHA associated with corpus callosum agenesis (CCA)

Haploinsufficiency of Dmxl2, Encoding a Synaptic Protein, Causes Infertility Associated with a Loss of GnRH Neurons in Mouse

International audienceCharacterization of the genetic defects causing gonadotropic deficiency has made a major contribution to elucidation of the fundamental role of Kisspeptins and Neurokinin B in puberty onset and reproduction. The absence of puberty may also reveal neurodevelopmental disorders caused by molecular defects in various cellular pathways. Investigations of these neurodevelopmental disorders may provide information about the neuronal processes controlling puberty onset and reproductive capacity. We describe here a new syndrome observed in three brothers, which involves gonadotropic axis deficiency, central hypothyroidism, peripheral demyelinating sensorimotor polyneuropathy, mental retardation, and profound hypoglycemia, progressing to nonautoimmune insulin-dependent diabetes mellitus. High-throughput sequencing revealed a homozygous in-frame deletion of 15 nucleotides in DMXL2 in all three affected patients. This homozygous deletion was associated with lower DMXL2 mRNA levels in the blood lymphocytes of the patients. DMXL2 encodes the synaptic protein rabconnectin-3a, which has been identified as a putative scaffold protein for Rab3-GAP and Rab3-GEP, two regulators of the GTPase Rab3a. We found that rabconnectin-3a was expressed in exocytosis vesicles in gonadotropin-releasing hormone (GnRH) axonal extremities in the median eminence of the hypothalamus. It was also specifically expressed in cells expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) within the pituitary. The conditional heterozygous deletion of Dmxl2 from mouse neurons delayed puberty and resulted in very low fertility. This reproductive phenotype was associated with a lower number of GnRH neurons in the hypothalamus of adult mice. Finally, Dmxl2 knockdown in an insulin-secreting cell line showed that rabconnectin-3a controlled the constitutive and glucose-induced secretion of insulin. In conclusion, this study shows that low levels of DMXL2 expression cause a complex neurological phenotype, with abnormal glucose metabolism and gonadotropic axis deficiency due to a loss of GnRH neurons. Our findings identify rabconectin-3a as a key controller of neuronal and endocrine homeostatic processes

Rabconnectin-3α is required for the morphological maturation of GnRH neurons and kisspeptin responsiveness

A few hundred hypothalamic neurons form a complex network that controls reproduction in mammals by secreting gonadotropin-releasing hormone (GnRH). Timely postnatal changes in GnRH secretion are essential for pubertal onset. During the juvenile period, GnRH neurons undergo morphological remodeling, concomitantly achieving an increased responsiveness to kisspeptin, the main secretagogue of GnRH. However, the link between GnRH neuron activity and their morphology remains unknown. Here, we show that brain expression levels of Dmxl2, which encodes the vesicular protein rabconnectin-3α, determine the capacity of GnRH neurons to be activated by kisspeptin and estradiol. We also demonstrate that Dmxl2 expression levels control the pruning of GnRH dendrites, highlighting an unexpected role for a vesicular protein in the maturation of GnRH neuronal network. This effect is mediated by rabconnectin-3α in neurons or glial cells afferent to GnRH neurons. The widespread expression of Dmxl2 in several brain areas raises the intriguing hypothesis that rabconnectin-3α could be involved in the maturation of other neuronal populations

Why Effective Medium Theory Fails in Granular Materials

Experimentally it is known that the bulk modulus, K, and shear modulus, \mu, of a granular assembly of elastic spheres increase with pressure, p, faster than the p^1/3 law predicted by effective medium theory (EMT) based on Hertz-Mindlin contact forces. To understand the origin of these discrepancies, we perform numerical simulations of granular aggregates under compression. We show that EMT can describe the moduli pressure dependence if one includes the increasing number of grain-grain contacts with p. Most important, the affine assumption (which underlies EMT), is found to be valid for K(p) but breakdown seriously for \mu(p). This explains why the experimental and numerical values of \mu(p) are much smaller than the EMT predictions.Comment: 4 pages, 5 figures, http://polymer.bu.edu/~hmaks