Carry Trade and Systemic Risk: Why are FX Options so Cheap?

In this paper we document first that, in contrast with their widely perceived excess returns, popular carry trade strategies yield low systemic-risk-adjusted returns. In particular, we show that carry trade returns are highly correlated with the return of a VIX rolldown strategy —i.e., the strategy of shorting VIX futures and rolling down its term structure— and that the latter strategy performs at least as well as betaadjusted carry trades, for individual currencies and diversified portfolios. In contrast, hedging the carry with exchange rate options produces large returns that are not a compensation for systemic risk. We show that this result stems from the fact that the corresponding portfolio of exchange rate options provides a cheap form of systemic insurance

Generalising Deep Learning MRI Reconstruction across Different Domains

We look into robustness of deep learning based MRI reconstruction when tested on unseen contrasts and organs. We then propose to generalise the network by training with large publicly-available natural image datasets with synthesised phase information to achieve high cross-domain reconstruction performance which is competitive with domain-specific training. To explain its generalisation mechanism, we have also analysed patch sets for different training datasets.Comment: Accepted for ISBI2019 as a 1-page abstrac

La motivación y cultura organizacional del personal administrativo de ESSALUD Tarapoto - 2014

La tesis denominada LA MOTIVACIÓN Y CULTURA ORGANIZACIONAL DEL PERSONAL ADMINISTRATIVO DE ESSALUD TARAPOTO - 2014, tuvo como problema fundamental ¿Cómo influye la motivación en la cultura organizacional del personal administrativo de Es salud Tarapoto - 2014?, el objetivo más importante fue evaluar la motivación y su influencia en la cultura organizacional del personal administrativo de Es salud Tarapoto 2014, desarrollando la hipótesis: La Motivación influye-significativamente en la cultura organizacional del personal administrativo de Es Salud Tarapoto 2014. La tesis realizando los cálculos estadísticos y contrastes necesarios, llegó a la conclusión más importante: La motivación no influye en la cultura organizacional del personal administrativo de Es salud Tarapoto 2014, pues los resultados indican que ambas variables son independientes una de la otra, ya que se puede apreciar en el contraste estadístico. Es necesario recordar que cuando buscamos necesidades de estudiar trabajos dedicados al clima institucional, siempre los resultados son tan vanados, de tal manera que se ven reflejados las principales necesidades de desarrollo institucional

Estimating the mean manifold of a deformable object from noisy observations

Assume we have a set of noisy observations (for example, images) of different objects, each undergoing a different geometric deformation, yet all the deformations belong to the same family. As a result of the action of these deformations, the set of different observations on each object is generally a manifold in the ambient space of observations. It has been shown, [1], that in the absence of noise, in those cases where the set of deformations admits a finite-dimensional representation, the universal manifold embedding (UME) provides a mapping from the space of observations to a low dimensional linear space. The manifold corresponding to each object is mapped to a distinct linear subspace of Euclidean space, and the dimension of the subspace is the same as that of the manifold. In the presence of noise, different observations are mapped to different subspaces. In this paper we derive a method for “averaging” the different subspaces, obtained from different observations made on the same object, in order to estimate the mean representation of the object manifold. The mean manifold representation is then employed to minimize the effects of noise in matched manifold detectors and to improve the separability of data sets in the context of object detection and classification

An order fitting rule for optimal subspace averaging

The problem of estimating a low-dimensional subspace from a collection of experimentally measured subspaces arises in many applications of statistical signal processing. In this paper we address this problem, and give a solution for the average subspace that minimizes an extrinsic mean-squared error, defined by the squared Frobenius norm between projection matrices. The solution automatically returns the dimension of the optimal average subspace, which is the novel result of the paper. The proposed order fitting rule is based on thresholding the eigenvalues of the average projection matrix, and thus it is free of penalty terms or other tuning parameters commonly used by other rank estimation techniques. Several numerical examples demonstrate the usefulness and applicability of the proposed criterion, showing how the dimension of the average subspace captures the variability of the measured subspaces.The work of I. Santamaría was supported by the Spanish Government through grants PRX14/0028 (Estancias de Movilidad de Profesores, Ministerio de Educación) and by project RACHEL (TEC2013-47141-C4-3-R) funded by the Ministerio de Economía y Competitividad (MINECO). The work of L. L. Scharf was supported by the National Science Foundation (NSF) under grant CCF-1018472

Data consistency networks for (calibration-less) accelerated parallel MR image reconstruction

We present simple reconstruction networks for multi-coil data by extending deep cascade of CNN's and exploiting the data consistency layer. In particular, we propose two variants, where one is inspired by POCSENSE and the other is calibration-less. We show that the proposed approaches are competitive relative to the state of the art both quantitatively and qualitatively.Comment: Presented at ISMRM 27th Annual Meeting & Exhibition (Abstract #4663

Polivictimización y bienestar social en universitarios de Colombia

Multiple violent events in the same individual is a frequent phenomenon and negatively affects the way in which people perceive their functioning in society. The present study aims to evaluate the relationship between Polyvictimization (PV) and Social Welfare (BS). An analytical observational study was designed. First semester students from a public university in the city of Santa Marta, Colombia, participated, who filled out the Trauma Symptoms Verification List (LVST) and the Keyes Social Well-being Scales. 590 students participated, aged between 18 to 57 years (M = 19.83 years; SD = 3.48), 55.3% male and 95.6% residing in socioeconomic stratum 1, 2 and 3. The multivariate analysis was estimated using opportunity ratios (OR) with a 95% confidence interval (95% CI). The PV was related to the dimensions of BS integration (OR = 1,832 95% CI 1,221-2,747), acceptance (OR = 1,663 95% CI 1,125-2,460) and social contribution OR = 1,715 95% CI 1,055-2,789). It is concluded that multiple violence is linked to the components of integration, acceptance and social contribution. Studies are needed to identify the impact of PV on other indicators of social welfare and on social capital in university students.Los múltiples sucesos violentos en un mismo individuo son un fenómeno frecuente que afecta de manera negativa la forma en la que las personas perciben su funcionamiento en la sociedad. La presente investigación tiene como objetivo evaluar la relación entre polivictimización (PV) y bienestar social a través de un estudio observacional analítico. Participaron estudiantes de primer semestre de una universidad pública de la ciudad de Santa Marta, Colombia, quienes diligenciaron la Lista de Verificación de Síntomas de Trauma (LVST) y la Escala de Bienestar Social de Keyes. Se contó con una muestra de 590 estudiantes, con edades comprendidas entre 18 y 57 años (M=19,83 años; DT=3,48). El 55,3% son de género masculino, y el 95,6% residen en estratos socioeconómicos 1, 2 y 3. El análisis multivariado se estimó mediante razones de oportunidad (OR) con intervalo de confianza del 95% (IC95%). La PV guardó relación con las dimensiones de BS integración (OR=1,832 IC95% 1,221-2,747), aceptación (OR=1,663 IC95% 1,125-2,460) y contribución social (OR=1,715 IC95% 1,055-2,789). Se concluye que la violencia múltiple se vincula con los componentes de integración, aceptación y contribución social. Es necesario realizar estudios para identificar el impacto de la PV en otros indicadores de bienestar social