Pompeu Fabra University

About: Pompeu Fabra University is a education organization based out in Barcelona, Spain. It is known for research contribution in the topics: Population & Context (language use). The organization has 8093 authors who have published 23570 publications receiving 858431 citations. The organization is also known as: Universitat Pompeu Fabra & UPF.

Trading genes along the silk road: mtDNA sequences and the origin of central Asian populations.

Abstract: Central Asia is a vast region at the crossroads of different habitats, cultures, and trade routes. Little is known about the genetics and the history of the population of this region. We present the analysis of mtDNA control-region sequences in samples of the Kazakh, the Uighurs, the lowland Kirghiz, and the highland Kirghiz, which we have used to address both the population history of the region and the possible selective pressures that high altitude has on mtDNA genes. Central Asian mtDNA sequences present features intermediate between European and eastern Asian sequences, in several parameters-such as the frequencies of certain nucleotides, the levels of nucleotide diversity, mean pairwise differences, and genetic distances. Several hypotheses could explain the intermediate position of central Asia between Europe and eastern Asia, but the most plausible would involve extensive levels of admixture between Europeans and eastern Asians in central Asia, possibly enhanced during the Silk Road trade and clearly after the eastern and western Eurasian human groups had diverged. Lowland and highland Kirghiz mtDNA sequences are very similar, and the analysis of molecular variance has revealed that the fraction of mitochondrial genetic variance due to altitude is not significantly different from zero. Thus, it seems unlikely that altitude has exerted a major selective pressure on mitochondrial genes in central Asian populations.

Hox Genes Regulate Digit Patterning by Controlling the Wavelength of a Turing-Type Mechanism

Abstract: The formation of repetitive structures (such as stripes) in nature is often consistent with a reaction-diffusion mechanism, or Turing model, of self-organizing systems. We used mouse genetics to analyze how digit patterning (an iterative digit/nondigit pattern) is generated. We showed that the progressive reduction in Hoxa13 and Hoxd11-Hoxd13 genes (hereafter referred to as distal Hox genes) from the Gli3-null background results in progressively more severe polydactyly, displaying thinner and densely packed digits. Combined with computer modeling, our results argue for a Turing-type mechanism underlying digit patterning, in which the dose of distal Hox genes modulates the digit period or wavelength. The phenotypic similarity with fish-fin endoskeleton patterns suggests that the pentadactyl state has been achieved through modification of an ancestral Turing-type mechanism.

Economic Growth with Bubbles

Abstract: This paper presents a stylized model of economic growth with bubbles. This model views asset price bubbles as a market-generated device to moderate the effects of frictions in financial markets, improving the allocation of investments and raising the capital stock and welfare. The model illustrates various channels through which asset price bubbles affect the incentives for innovation and economic reforms, and therefore, the rate of economic growth. The model also offers a new perspective on the effects of financial development on asset price bubbles and economic growth.

Prospective Study of FGFR3 Mutations As a Prognostic Factor in Nonmuscle Invasive Urothelial Bladder Carcinomas

Abstract: Purpose To determine the frequency and the prognostic value of fibroblast growth factor receptor 3 (FGFR3) mutations in patients with nonmuscle invasive bladder tumors according to tumor stage and grade. Patients and Methods Seven hundred seventy-two patients with newly diagnosed bladder tumors were recruited. Tumors were reviewed by expert pathologists. Patients were prospectively followed-up (median, 62.6 months for disease-free patients) through review of hospital records and telephone interviews. The sequence of exons 7 and 10 of FGFR3 was analyzed by polymerase chain reaction and direct sequencing. We assessed the association of mutations with stage and grade. The predictive value of mutations for recurrence, progression, and mortality were assessed using Kaplan-Meier and Cox multivariable models. Results Mutations were more common among low malignant potential neoplasms (LMPN; 77%) and TaG1/TaG2 tumors (61%/58%) than among TaG3 tumors (34%) and T1G3 tumors (17%). The S249C, Y375C, S248C, and G372C m...

Out-of-Sample Forecast Tests Robust to the Choice of Window Size

Abstract: This article proposes new methodologies for evaluating economic models’ out-of-sample forecasting performance that are robust to the choice of the estimation window size. The methodologies involve evaluating the predictive ability of forecasting models over a wide range of window sizes. The study shows that the tests proposed in the literature may lack the power to detect predictive ability and might be subject to data snooping across different window sizes if used repeatedly. An empirical application shows the usefulness of the methodologies for evaluating exchange rate models’ forecasting ability.