Análisis de mercados inmobiliarios (un enfoque desde cointegración y econometría espacial)

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Económicas y Empresariales, Departamento de Fundamentos del Análisis Económico II (Economía Cuantitativa), leída el 28/06/2016. Tesis formato europeo (compendio de artículos)The first chapter of this thesis examines the formation process of residential prices in Spain (1995Q1 – 2012Q4). We propose two models to compare their performance in the context of comparative dynamics and predictive capacity. A structural model is derived from an eclectic theoretical framework in which we review published literature on the housing market and select a set of variables representative of this literature. We used GDP pre-capita, interest rates, the supply of new residential buildings and the gross residential-capital formation as explanatory variables for the average house price per square meter in Spain. The other model is generated by an algorithm known as GASIC2. Using our review of the literature we select a set of 46 variables, we form the respective database and let the algorithm to select the best model out the 2 (70 trillion) nested models. The condition imposed on the algorithm is to be parsimonious, i.e. having only 4 regressors. Annual theoretical effort of families to pay for their residence, the apparent concrete consumption, the mortgage interest rate and the real GDP are selected by GASIC to explain the average residential price in Spain; a similar model to the structural one. Our analytical framework is cointegration. Therefore, we assessed the integration order of both models’ variables. We identified all variables have order of integration of first degree (some with a structural break in the recent economic crisis). This leads us to test the hypothesis of cointegration. Proving such an existence, two error correction models (ECM) were estimated (one for the structural approach and one for the algorithmic) to calculate price and income elasticities, and produce dynamic forecasts. The long-term equations in both models behave similarly and give a good idea of the long-term equilibrium relationship between housing prices and their fundamentals. It is in the short term specification where the structural model and the algorithmic model differ. The model generated with GASIC has got a non-significant error correction mechanism, implying that the gap between the change in housing prices and longterm path is not traced. The consequence of such failure generates less accurate house price forecasts. However, the analysis of elasticities remains valid in both long and short term price equations...El primer capítulo de esta tesis analiza el proceso de formación del precio medio residencial por metro cuadrado en España (T1 1995 – T4 2012). Proponemos dos modelos para comparar su rendimiento en los contextos de estática comparativa y capacidad predictiva. Un modelo es estructural, derivado de un marco teórico ecléctico en el cual revisamos la literatura publicada en el sector inmobiliario residencial y seleccionamos un conjunto de variables representativo de esta literatura. Utilizamos el PIB per cápita, las tasa de interés, las entregas de los nuevos edificios residenciales y la formación bruta de capital inmobiliario como variables explicativas del precio residencial medio por metro cuadrado en España. El otro modelo es generado por un algoritmo conocido como GASIC4 . De nuestra revisión de la literatura seleccionamos un conjunto de 46 variables, formamos la respectiva base de datos y dejamos que algoritmo conforme el mejor modelo posible de los 2 (70 billones) modelos anidados. La condición impuesta al algoritmo es que sea parsimonioso, o sea, que tenga solo 4 regresores. El esfuerzo teórico anual de las familias para pagar su residencia, la producción aparente de concreto, el tipo de interés hipotecario y el PIB real son seleccionados por GASIC para explicar el precio medio residencial en España; un modelo similar al estructural. Nuestro marco analítico es de cointegración. Por lo tanto, evaluamos el orden de integración de las variables de ambos modelos. Se ha identificado que todas tienen orden de integración de primer grado (algunas de ellas con un shock estructural en la reciente crisis económica). Esto nos da pie para probar la hipótesis de cointegración. Demostrando tal existencia, se han estimado dos modelos de corrección del error (ECM) para calcular elasticidades precio e ingreso y producir previsiones dinámicas. Las ecuaciones de largo plazo en ambos modelos se comportan de forma similar dan buena idea de la relación de equilibrio de largo plazo entre el precios de la vivienda y sus variables fundamentales. Es en la especificación de corto plazo cuando el modelo estructural y el modelo algorítmico difieren. En el modelo generado por GASIC, el mecanismo de corrección del error es no significativo, lo que implica que la brecha entre la variación de precios de viviendas y su senda de largo plazo no es capturada por el modelo. La consecuencia de tal falta genera previsiones menos precisas de los precios del inmobiliario residencial. Sin embargo, el análisis de las elasticidades sigue siendo válido para ambas especificaciones de largo y corto plazo...Depto. de Análisis Económico y Economía CuantitativaFac. de Ciencias Económicas y EmpresarialesTRUEunpu

Office Market Dynamics in Madrid : Modelling with a Single-Equation Error Correction Mechanism

This paper seeks to explain the office market dynamics in Madrid by using cointegration models. Specifically, we focus on the equilibrium path of stock, vacancy rate and letting rents, and feedback with two exogenous economic determinants, namely, service sector employment and gross domestic product. We apply for the first time a single-equation error correction mechanism (ECM) to a system of equations for the commercial property market of Madrid and examine its accuracy when compared to the more frequently used classical two-step ECM. The main findings to emerge from our empirical analysis are that rents and vacancy rates react rapidly when they do not correspond to their equilibrium level. Stock, as expected, responds more slowly when it does not correspond to its long-term path. We draw on quarterly observations for the Madrid market between 2001:Q1 and 2015:Q2

Evaluation of night-time aerosols measurements and lunar irradiance models in the frame of the first multi-instrument nocturnal intercomparison campaign

The first multi-instrument nocturnal aerosol optical depth (AOD) intercomparison campaign was held at the high-mountain Izaña Observatory (Tenerife, Spain) in June 2017, involving 2-min synchronous measurements from two different types of lunar photometers (Cimel CE318-T and Moon Precision Filter Radiometer, LunarPFR) and one stellar photometer. The Robotic Lunar Observatory (ROLO) model developed by the U.S. Geological Survey (USGS) was compared with the open-access ROLO Implementation for Moon photometry Observation (RIMO) model. Results showed rather small differences at Izaña over a 2-month time period covering June and July, 2017 (±0.01 in terms of AOD calculated by means of a day/night/day coherence test analysis and ± 2% in terms of lunar irradiance). The RIMO model has been used in this field campaign to retrieve AOD from lunar photometric measurements. No evidence of significant differences with the Moon's phase angle was found when comparing raw signals of the six Cimel photometers involved in this field campaign. The raw signal comparison of the participating lunar photometers (Cimel and LunarPFR) performed at coincident wavelengths showed consistent measurements and AOD differences within their combined uncertainties at 870 nm and 675 nm. Slightly larger AOD deviations were observed at 500 nm, pointing to some unexpected instrumental variations during the measurement period. Lunar irradiances retrieved using RIMO for phase angles varying between 0° and 75° (full Moon to near quarter Moon) were compared to the irradiance variations retrieved by Cimel and LunarPFR photometers. Our results showed a relative agreement within ± 3.5% between the RIMO model and the photometer-based lunar irradiances. The AOD retrieved by performing a Langley-plot calibration each night showed a remarkable agreement (better than 0.01) between the lunar photometers. However, when applying the Lunar-Langley calibration using RIMO, AOD differences of up to 0.015 (0.040 for 500 nm) were found, with differences increasing with the Moon's phase angle. These differences are thought to be partly due to the uncertainties in the irradiance models, as well as instrumental deficiencies yet to be fully understood. High AOD variability in stellar measurements was detected during the campaign. Nevertheless, the observed AOD differences in the Cimel/stellar comparison were within the expected combined uncertainties of these two photometric techniques. Our results indicate that lunar photometry is a more reliable technique, especially for low aerosol loading conditions. The uncertainty analysis performed in this paper shows that the combined standard AOD uncertainty in lunar photometry is dependent on the calibration technique (up to 0.014 for Langley-plot with illumination-based correction, 0.012–0.022 for Lunar-Langley calibration, and up to 0.1 for the Sun-Moon Gain Factor method). This analysis also corroborates that the uncertainty of the lunar irradiance model used for AOD calculation is within the 5–10% expected range. This campaign has allowed us to quantify the important technical difficulties that still exist when routinely monitoring aerosol optical properties at night-time. The small AOD differences observed between the three types of photometers involved in the campaign are only detectable under pristine sky conditions such as those found in this field campaign. Longer campaigns are necessary to understand the observed discrepancies between instruments as well as to provide more conclusive results about the uncertainty involved in the lunar irradiance models.This work has been developed within the framework of the activities of the World Meteorological Organization (WMO) Commission for Instruments and Methods of Observations (CIMO) Izaña Testbed for Aerosols and Water Vapour Remote Sensing Instruments. AERONET sun photometers at Izaña have been calibrated within the AERONET Europe TNA, supported by the European Union’s Horizon 2020 research and innovation program under grant agreement no. 654109 (ACTRIS‒2). CE318-T linearity check has been performed as part of the ESA-funded project “Lunar spectral irradiance measurement and modelling for absolute calibration of EO optical sensors” under ESA contract number: 4000121576/17/NL/AF/hh. LunarPFR has been performing measurements since 2014 in Norway thanks to Svalbard Science Forum funded project, 2014–2016. The authors would like to thank AERONET team for their support and also to NASA’s Navigation and Ancillary Information Facility (NAIF) at the Jet Propulsion Laboratory to help the implementation of the “SPICE” ancillary information system used in this study. We also thank Izaña's ITs for their work to implement the RIMO model in the free-access server. Special thanks should be given to Tom Stone, who has kindly provided us with the USGS/ROLO irradiance values used in the model comparison analysis. This work has also received funding from the European Union’s Horizon 2020 research and innovation programme and from Marie Skłodowska-Curie Individual Fellowships (IF) ACE-GFAT (grant agreement no. 659398). The authors are grateful to Spanish MINECO (CTM2015-66742-R) and Junta de Castilla y León (VA100P17)

Association between Use of Enhanced Recovery after Surgery Protocol and Postoperative Complications in Total Hip and Knee Arthroplasty in the Postoperative Outcomes Within Enhanced Recovery after Surgery Protocol in Elective Total Hip and Knee Arthroplasty Study (POWER2)

Importance: The Enhanced Recovery After Surgery (ERAS) care protocol has been shown to improve outcomes compared with traditional care in certain types of surgery. Objective: To assess the association of use of the ERAS protocols with complications in patients undergoing elective total hip arthroplasty (THA) and total knee arthroplasty (TKA). Design, Setting, and Participants: This multicenter, prospective cohort study included patients recruited from 131 centers in Spain from October 22 through December 22, 2018. All consecutive adults scheduled for elective THA or TKA were eligible for inclusion. Patients were stratified between those treated in a self-designated ERAS center (ERAS group) and those treated in a non-ERAS center (non-ERAS group). Data were analyzed from June 15 through September 15, 2019. Exposures: Total hip or knee arthroplasty and perioperative management. Sixteen individual ERAS items were assessed in all included patients, whether they were treated at a center that was part of an established ERAS protocol or not. Main Outcomes and Measures: The primary outcome was postoperative complications within 30 days after surgery. Secondary outcomes included length of stay and mortality. Results: During the 2-month recruitment period, 6146 patients were included (3580 women [58.2%]; median age, 71 [interquartile range (IQR), 63-76] years). Of these, 680 patients (11.1%) presented with postoperative complications. No differences were found in the number of patients with overall postoperative complications between ERAS and non-ERAS groups (163 [10.2%] vs 517 [11.4%]; odds ratio [OR], 0.89; 95% CI, 0.74-1.07; P =.22). Fewer patients in the ERAS group had moderate to severe complications (73 [4.6%] vs 279 [6.1%]; OR, 0.74; 95% CI, 0.56-0.96; P =.02). The median overall adherence rate with the ERAS protocol was 50.0% (IQR, 43.8%-62.5%), with the rate for ERAS facilities being 68.8% (IQR, 56.2%-81.2%) vs 50.0% (IQR, 37.5%-56.2%) at non-ERAS centers (P <.001). Among the patients with the highest and lowest quartiles of adherence to ERAS components, the patients with the highest adherence had fewer overall postoperative complications (144 [10.6%] vs 270 [13.0%]; OR, 0.80; 95% CI, 0.64-0.99; P <.001) and moderate to severe postoperative complications (59 [4.4%] vs 143 [6.9%]; OR, 0.62; 95% CI, 0.45-0.84; P <.001) and shorter median length of hospital stay (4 [IQR, 3-5] vs 5 [IQR, 4-6] days; OR, 0.97; 95% CI, 0.96-0.99; P <.001). Conclusions and Relevance: An increase in adherence to the ERAS program was associated with a decrease in postoperative complications, although only a few ERAS items were individually associated with improved outcomes

Experimental study of differentially rotating supersonic plasma flows produced by aluminium wire array Z-pinches

A novel approach to cylindrical wire array z-pinches has been developed in order to create a rotating plasma flow analogous to astrophysical accretion discs. The method involves subjecting the wire array to a cusp magnetic field (B_r) to create converging off axis ablation streams to form a rotating flow. The rotation is sustained by the ram pressure of the ablation streams in a quasi-equilibrium state for approximately 150 ns. This corresponds to one full rotation of the plasma about the axis. The rotating plasma is supersonic with Mach number ~2 and a radially constant rotation velocity between 60 and 75 km/s; the angular velocity therefore has an r^-1 dependence and the flow is differential. A Thomson scattering diagnostic is used to measure the electron and ion temperatures as Te ~30 eV and Ti >55 eV and the ionisation of the plasma (Z) between 6 and 8. These parameters are used to calculate the Reynolds number (10^5 to 10^6) and magnetic Reynolds numbers (20 to 100) which are large enough for viscous and resistive effects to be negligible on the large scale of the flow. These are of sufficient magnitude for the experiment to be scalable to astrophysical accretion discs. Further more the Reynolds number for the experiment is large enough for shear instabilities to manifest in the plasma. Some evidence for this can be seen in XUV images and Thomson spectra which indicate the development of perturbations and vorticity within the flow. Predictions for the growth rate of the Kelvin Helmholtz instability, 12 to 40 ns, agree reasonably well with the observed perturbation growth of ~30 ns. It is also possible that shear instabilities are driving hydrodynamic turbulence. Turbulent heating of the plasma could explain the approximately 500 eV increase in the ion temperature observed from some Thomson spectra. Further work is required however to prove the existence of shear flows and turbulence within the experiments.Open Acces

Evidence of spatial clustering of childhood acute lymphoblastic leukemia cases in Greater Mexico City: report from the Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia

BackgroundA heterogeneous geographic distribution of childhood acute lymphoblastic leukemia (ALL) cases has been described, possibly, related to the presence of different environmental factors. The aim of the present study was to explore the geographical distribution of childhood ALL cases in Greater Mexico City (GMC).MethodsA population-based case-control study was conducted. Children &lt;18 years old, newly diagnosed with ALL and residents of GMC were included. Controls were patients without leukemia recruited from second-level public hospitals, frequency-matched by sex, age, and health institution with the cases. The residence address where the patients lived during the last year before diagnosis (cases) or the interview (controls) was used for geolocation. Kulldorff’s spatial scan statistic was used to detect spatial clusters (SCs). Relative risks (RR), associated p-value and number of cases included for each cluster were obtained.ResultsA total of 1054 cases with ALL were analyzed. Of these, 408 (38.7%) were distributed across eight SCs detected. A relative risk of 1.61 (p&lt;0.0001) was observed for the main cluster. Similar results were noted for the remaining seven ones. Additionally, a proximity between SCs, electrical installations and petrochemical facilities was observed.ConclusionsThe identification of SCs in certain regions of GMC suggest the possible role of environmental factors in the etiology of childhood ALL

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Características eletrocardiográficas e eletrofisiológicas basais em pacientes com taquicardia ventricular idiopática

As taquicardias ventriculares (TV) idiopáticas representam aproximadamente 10% dos tipos desta arritmia, portanto, sao pouco frequentes. Propusemo-nos a analisar o eletrocardiograma (ECG) e o hisiograma basal em nossa série de pacientes com diagnóstico de TV idiopática. Material e Métodos: Dos 15 pacientes apresentados consecutivamente entre janeiro de 2004 e dezembro de 2007, para os quais foi confirmado o diagnóstico de TV idiopática, foi registrado o ECG e o hisiograma em ritmo sinusal antes da estimulaçao, para a mediçao de variáveis. Resultados: A frequência cardíaca foi maior (86,0 ± 17,3 vs. 81,3 ± 9,9; pConclusoes: Nenhuma das mediçoes eletrocardiográficas rebaixou os limites normais. Houve grande coincidência entre o eixo frontal, a duraçao e a morfologia do QRS dos complexos ventriculares prematuros com a variante do TSVD e foi muito menor para as TV fasciculares. Os parâmetros do hisiograma nao se manifestaram de forma patológica embora a média do intervalo HV tenha sido discretamente superior à normalidade em ambos os tipos de TV sem que isso tivesse conotaçao clínica

Características eletrocardiográficas e eletrofisiológicas basais em pacientes com taquicardia ventricular idiopática

As taquicardias ventriculares (TV) idiopáticas representam aproximadamente 10% dos tipos desta arritmia, portanto, sao pouco frequentes. Propusemo-nos a analisar o eletrocardiograma (ECG) e o hisiograma basal em nossa série de pacientes com diagnóstico de TV idiopática. Material e Métodos: Dos 15 pacientes apresentados consecutivamente entre janeiro de 2004 e dezembro de 2007, para os quais foi confirmado o diagnóstico de TV idiopática, foi registrado o ECG e o hisiograma em ritmo sinusal antes da estimulaçao, para a mediçao de variáveis. Resultados: A frequência cardíaca foi maior (86,0 ± 17,3 vs. 81,3 ± 9,9; pConclusoes: Nenhuma das mediçoes eletrocardiográficas rebaixou os limites normais. Houve grande coincidência entre o eixo frontal, a duraçao e a morfologia do QRS dos complexos ventriculares prematuros com a variante do TSVD e foi muito menor para as TV fasciculares. Os parâmetros do hisiograma nao se manifestaram de forma patológica embora a média do intervalo HV tenha sido discretamente superior à normalidade em ambos os tipos de TV sem que isso tivesse conotaçao clínica