A multifactor model of stock returns with endogenous regime switching

We estimate a state-dependent multifactor model with two endogenous states. Its pricing accuracy is slightly superior to that of the Fama and French (1993, 1996) model. We have evidence for dramatically increased factor loadings for distress factors in one state. These results have implications for cost-of-capital calculations, portfolio management, risk analysis and other applications.Empirical asset pricing, endogenous regime switching, state-dependent models, nonstandard maximum-likelihood estimation

Quantitative effects of the shale oil revolution

El objetivo de este trabajo es analizar el impacto de la llamada «revolución del petróleo no convencional» sobre los precios del petróleo y el crecimiento económico. Para ello se utiliza un modelo de equilibrio general del mercado internacional de crudo en el que Arabia Saudita es el productor dominante, actuando los restantes productores como precio-aceptantes. Nuestros resultados sugieren que los precios del crudo ya han incorporado la mayor parte del incremento esperado en la producción de crudo no convencional norteamericana, y que esto producirá un aumento del 0,2 % del PIB de las economías importadoras de petróleo durante el período 2010-2018. También empleamos el modelo para analizar el colapso en los precios del crudo ocurrido en la segunda mitad de 2014 y concluimos que fue debido principalmente a perturbaciones no anticipadas de la oferta de crudoThe aim of this paper is to analyse the impact of the so-called «shale oil revolution» on oil prices and economic growth. We employ a general equilibrium model of the world oil market in which Saudi Arabia is the dominant fi rm, with the rest of the producers as a competitive fringe. Our results suggest that most of the expected increase in US oil supply due to the shale oil revolution has already been incorporated into prices and that it will produce an additional increase of 0.2 percent in the GDP of oil importers in the period 2010-2018. We also employ the model to analyse the collapse in oil prices in the second half of 2014 and conclude that it was mainly due to positive unanticipated supply shock

El diaconado femenino en la época bizantina

La aparición del cristianismo cambió radicalmente el status de la mujer: de ser una persona sumisa y sin derechos pasó a ser un ser humano más respetado. Este artículo se centra en el papel de las mujeres en los primeros tiempos de la historia de la Iglesia, y estudia su implicación en diferentes aspectos: como acompañantes de Jesús y de los apóstoles, su apoyo a la evangelización, la aparición del orden de las viudas, las diaconisas y las vírgenes consagradas. Enfoca con especial interés la institución de las diaconisas, sus funciones y su papel a lo largo de los siglos hasta que se produjo su desaparición por causas diversas, entre las que se encuentra la romanización de la liturgia con una fuerte jerarquía masculina.With Christianity the status of women changed radically: from being submissive and without rights they became more respected human beings. This article discusses the role of women at the beginning of the history of Church, and studies their implication in different ways: from the company of the Jesus and the apostles, their support to the evangelization, the apparition of the order of the widows, deaconesses and consecrated virgins. It focuses on the institution of women deacon, their functions and roles along centuries, until it disappears due to different causes, one of which was the Romanization of liturgy with a strong masculine hierarchy

Structure-dependent amplification for denoising and background correction in Fourier ptychographic microscopy

Fourier Ptychographic Microscopy (FPM) allows high resolution imaging using iterative phase retrieval to recover an estimate of the complex object from a series of images captured under oblique illumination. FPM is particularly sensitive to noise and uncorrected background signals as it relies on combining information from brightfield and noisy darkfield (DF) images. In this article we consider the impact of different noise sources in FPM and show that inadequate removal of the DF background signal and associated noise are the predominant cause of artefacts in reconstructed images. We propose a simple solution to FPM background correction and denoising that outperforms existing methods in terms of image quality, speed and simplicity, whilst maintaining high spatial resolution and sharpness of the reconstructed image. Our method takes advantage of the data redundancy in real space within the acquired dataset to boost the signal-to-background ratio in the captured DF images, before optimally suppressing background signal. By incorporating differentially denoised images within the classic FPM iterative phase retrieval algorithm, we show that it is possible to achieve efficient removal of background artefacts without suppression of high frequency information. The method is tested using simulated data and experimental images of thin blood films, bone marrow and liver tissue sections. Our approach is non-parametric, requires no prior knowledge of the noise distribution and can be directly applied to other hardware platforms and reconstruction algorithms making it widely applicable in FPM