Pricing tranched credit products with generalized multifactor models

The market for tranched credit products (CDOs, Itraxx tranches) is one of the fastest growing segments in the credit derivatives industry. However, some assumptions underlying the standard Gaussian onefactor pricing model (homogeneity, single factor, Normality), which is the pricing standard widely used in the industry, are probably too restrictive. In this paper we generalize the standard model by means of a two by two model (two factors and two asset classes). We assume two driving factors (business cycle and industry) with independent tStudent distributions, respectively, and we allow the model to distinguish among portfolio assets classes. In order to illustrate the estimation of the parameters of the model, an empirical application with Moody's data is also included

Research about the pozzolanic activity of waste materials from calcined clay

[EN]To recycle and reutilise waste materials and find definite applications for their use, it is necessary to have a deep knowledge of them. The aim of this study is to study the possibility of using waste materials from calcined clay, actually ceramic tile, once crushed and grounded, as pozzolanic material. For this purpose, different tests are carried out in order to establish the pozzolanic activity of this material. At the same time, these results are compared to those of other industrial by-products, fly ash and silica fume, which are pozzolanic materials usually employed to elaborate mortars and concretes.[ES] Para llevar a cabo labores encaminadas al reciclado y revalorización de residuos es necesario un conocimiento profundo de los mismos, de forma que se busquen aplicaciones concretas de uso. El objetivo de este estudio es investigar la posibilidad de utilizar materiales de desecho procedentes de arcilla cocida, concretamente teja cerámica, una vez triturada y molida, como puzolana. Para ello, se efectúan diferentes ensayos dirigidos a establecer la actividad puzolanica del material. A su vez, estos resultados son comparados con otros residuos industriales, ceniza volante y humo de sílice, habituales en la elaboración de morteros y hormigones.Peer reviewe

Preliminary results on climate change evidence from coprolites of Myotragus balearicus Bate 1909 (Artiodactyla, Caprinae)

Plants may vary their stomata density as a function of environmental factors, such as [CO2], drought and temperature. Under the present atmospheric conditions, it is expected that leaves have different stomata density than they had hundreds or thousands of years ago, due to the rise of CO2 in the atmosphere. Microhistological analyses of coprolites of the extinct Myotragus balearicus from Cova Estreta (Pollença, Mallorca), with a radiocarbon age of 4950 ± 38 BP (3775-3640 2σ cal BC; Wk-33010), have shown a diet including an important amount of Buxus balearica epidermal fragments. Three of these coprolites were used to estimate the stomata density on Buxus balearica epidermal fragments from this period. Additionally, three samples of the endangered Buxus balearica, the sole species of Buxus currently present on Mallorca, were collected in three different localities and leaves were examined under microscopy to determine the stomata density. A significant difference between epidermal fragments from coprolites and epidermal fragments of living plants (c² = 34.46, P<0.0001, L-R c² test), with a density average of 27.21 and 19.05 stomata/mm2 res pectively, has been recorded. The current lower density of stomata could be a plant response to climatic change in the Mediterranean islands

Neutron radiobiology studies with a pure cold neutron beam

Data on the radiobiological effects of thermal neutrons are usually obtained from irradiations in a mixed field of neutrons of different energies and gamma rays or from conversion of proton data with similar energies to those created in the neutron capture on nitrogen. Experimental data from irradiations in a pure thermal or cold neutron beam can help to find new values for neutron relative biological effectiveness (RBE) factors, which are useful for BNCT (Boron Neutron Capture Therapy) and radiation protection applications. We present a new experimental setup for radiobiological studies at a cold neutron beam at Institut Laue-Langevin, a beam without fast neutron component and almost no gamma ray contribution. After the irradiation, survival assays are performed to obtain the survival curves. Finally, comparing with a reference photon irradiation, the thermal neutron RBE factors can be calculated. The methodology is outlined at the example of A375 melanoma cells for which new radiobiological data were obtained.We acknowledge financial support for this work from the Fundación Científica de la Asociación Española Contra el Cáncer (AECC) under grant PS16163811PORR, Junta de Andalucía (Andalusian Regional Government), under contract P11-FQM-8229, Spanish MINECO and FEDER funds under contract FIS2015-69941-C2-1-P, the grant agreement ILL-UGR and the founders of the University of Granada Chair Neutrons for Medicine: Spanish Fundación ACS and Capitán Antonio. M.P. acknowledges a grant under the program Becas de Iniciación a la Investigación from the Universidad de Granada (Plan Propio de Investigación). The open access fee was covered by FILL2030, a European Union project within the European Commission’s Horizon 2020 Research and Innovation programme under grant agreement N°731096

INCIDENCIA DE INFECCIÓN POR Leptospira sp. EN RONSOCOS (Hydrochoerus hydrochaeris) EN CAUTIVERIO EN UN ZOOCRIADERO DE IQUITOS

The objective of this study was to determine the incidence of Leptospira sp., in capybaras (Hydrochoerus hydrochaeris) from a zoo farm in Iquitos, Loreto, Peru. Blood samples from 36 young and adults capyrabas, both female and male, were collected in three samplings periods with a 2-month interval for detecting antibodies against 13 serovars of Leptospira sp. by microaglutination test. The 97.2, 100 y 100% of the samples collected during the first, second and third sampling period had antibodies against Leptospira sp. respectively. The serovar georgia, canicola and ballum were detected in the first, second and third sample, pomona and australis in the second and third, and tarassovi only in the third sampling period. The most frequent serovars were georgia, canicola, and ballum. The accumulated incidence of Leptospira sp. infection was 86.0 ± 18.2% (31/36) animals/0.25year. The accumulated incidence of each serovar also indicated that georgia (100%), ballum (36.3%), canicola (25.8%) and tarassovi (16.6%) were the more frequent. The samples resulted negative to antibodies against the serovars icterohemorrhagiae, wolffi, hardjo, bratislava, grippotyphosa and javanica. The results indicate that Leptospira sp. infection is endemic on the capyraba population in the zoo farm in Iquitos city.El objetivo del presente estudio fue determinar la incidencia de la infección de Leptospira sp. en ronsocos (Hydrochoerus hydrochaeris) de un zoocriadero en Iquitos. Se colectó muestras de sangre de 36 ronsocos adultos y juveniles de ambos sexos en tres muestreos con intervalo entre muestreos de dos meses, para la detección de anticuerpos contra 13 serovariedades de Leptospira sp. mediante la técnica de microaglutinación. Anticuerpos leptospirales fueron detectados en 97.2, 100 y 100% en el primer, segundo y tercer muestreo, respectivamente. Las serovariedades georgia, canicola y ballum fueron detectadas en los tres muestreos, pomona y australis en el segundo y tercer muestreo, mientras que tarassovi solo en el tercer muestreo. La serovariedad de mayor frecuencia fue georgia seguida por canicola y ballum. La incidencia acumulada con anticuerpos leptospirales fue 86.0 ± 18.2% (31/36) de animales/0.25 año, que es la proporción de animales que se infectaron con Leptospira sp. en los cuatro meses de observación. La incidencia acumulada de georgia (100%), ballum (36.3%), canicola (25.8%) y tarassovi (16.6%) fueron las más importantes. Las muestras resultaron negativas a anticuerpos contra las serovariedades: icterohemorrhagiae, wolffi, hardjo, bratislava, grippotyphosa y javanica. Los resultados del presente estudio indican que la infección por Leptospira sp. es endémica en la población de ronsocos del zoocriadero en estudio

Pulmonary embolism response teams: Changing the paradigm in the care for acute pulmonary embolism

Pulmonary embolism response teams (PERTs) have emerged as a multidisciplinary, multispecialty team of experts in the care of highly complex symptomatic acute pulmonary embolism (PE), with a centralized unique activation process, providing rapid multimodality assessment and risk stratification, formulating the best individualized diagnostic and therapeutic approach, streamlining the care in challenging clinical case scenarios (e.g., intermediate-high risk and high-risk PE), and facilitating the implementation of the recommended therapeutic strategies on time. PERTs are currently changing how complex acute PE cases are approached. The structure, organization, and function of a given PERT may vary from hospital to hospital, depending on local expertise, specific resources, and infrastructure for a given academic hospital center. Current emerging data demonstrate the value of PERTs in improving time to PE diagnosis; shorter time to initiation of anticoagulation reducing hospital length of stay; increasing use of advanced therapies without an increase in bleeding; and in some reports, decreasing mortality. Importantly, PERTs are positively impacting outcomes by changing the paradigm of care for acute PE through global adoption by the health-care community

Craneocervical posture in children after treatment with chincap. A pilot study

ABSTRACT: The aim of this study was to describe the changes in the craniocervical posture in children with skeletal class III malocclusion (prognathic mandible) after wearing chincap with lower occlusal bite plane. Methods: the sample consisted of eleven children (7 girls and 4 boys). Three lateral cephalic radiographs were taken for each child with the head in natural position (“mirror position”), with light occlusal contact. The first radiograph (T1) was taken before wearing the chincap, the second (T2) was taken four months after wearing the appliance and the third (T3) was taken four months after removing the chincap. Specific angular and linear dimensions were used; the comparison within the group was performed using Descriptive Analysis and the Normality (Shapiro-Wilk) y Friedman Signed Rank Test. Results: statistical analysis didn’t show significant changes in any of the angular and linear measurements analyzed nor at any of the times studied. Conclusion: even though there is a great individual variability in the cranial, cervical and craniocervical posture of the tested children, in general, there were no statistical significant changes in cervical posture after treatment with chincap and lower occlusal bite plane.RESUMEN: El propósito del presente estudio fue describir los cambios en la postura craneocervical en una población infantil con clase III esquelética por prognatismo mandibular, luego de la utilización de mentonera con placa de acetato inferior para levantar la mordida. Métodos: la muestra consistió de once niños (siete niñas y cuatro niños). A cada niño le fueron tomadas tres radiografías cefálicas laterales en posición natural de cabeza (mirando de frente a un espejo), con ligero contacto oclusal. La primera radiografía (T1) fue tomada antes de iniciar la utilización de la mentonera, la segunda (T2), cuatro meses después de su uso y la tercera (T3), cuatro meses después de retirada. Para el análisis se emplearon medidas lineales y angulares, se realizó análisis descriptivo de las variables y se utilizaron las pruebas de normalidad (Shapiro-Wilk) y Friedman. Resultados: el análisis estadístico no mostró diferencias significativas en ninguna de las variables analizadas, y en ninguno de los momentos evaluados. Conclusión: a pesar de la gran variabilidad individual en la postura craneal, cervical y craneocervical de los niños evaluados, en general no se observaron en esta muestra cambios significativos en la columna cervical, luego del tratamiento con mentonera y placa de acetato inferior que levantaba la mordida

Toxoplasma gondii seropositivity associated to peri-urban living places in pregnant women in a rural area of Buenos Aires province, Argentina

Infection with Toxoplasma gondii is very common in humans throughout the world, the intake of raw or undercooked meat with tissue cysts and fruits, vegetables and water contaminated with parasite oocysts being the main routes of infection. Here, we analyzed the seroprevalence of anti-T. gondii antibodies in pregnant females (age 13–44 years; n = 920) between April 2014 and December 2017 from Chascomús (Argentina), a city immersed in a rural area. Altogether 320 tested positive for immunoglobulin G antibodies, yielding an overall seroprevalence of 34.8% (CI 95%: 31.7–37.9). No association was observed between seropositivity and age. In addition, by using the QGIS 3.2.1 software we analyzed the geographical distribution of 769 (83.6%) pregnant females in two main areas of the city: Urban (n = 157) and Peri-urban (n = 612) with a seroprevalence of 26.8% (CI 95%: 19.8–33.7) and 36.4% (CI 95%: 32.6–40.3) respectively, and this difference was statistically significant (p = 0.023). Furthermore, we assessed through a questionnaire survey, between April 2016 to December 2017, possible risk factors such as activity (urban and rural), home water supply, animal husbandry, presence of cats as pets, gardening and consumption of meat and its derivatives (pork, sheep meat and sausages) and their frequencies (consumption per week), not finding significant association with seropositivity. Significant differences was found when the seroprevalence was analyzed between the urban and peri-urban neighborhoods of the city of Chascomús. The higher seroprevalence in peri-urban neighborhoods could be due to an unfavorable socioeconomic situation and/or to undeveloped peri-urban environments, which is a risk factor that should be taken into account when planning the health care of pregnant females.Fil: Rivera, Elias Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Lavayén, Silvina N.. Dirección Nacional del Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr.C.G.Malbran". Instituto Nacional de Epidemiologia; ArgentinaFil: Sánchez, Paola. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Martins, Carlos M. A.. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Gómez, Etelvina. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Rodríguez, Jorge P.. Hospital Municipal de Chascomus San Vicente de Paul; ArgentinaFil: Arias, Marcela E.. Secretaría de Salud. Municipalidad de Chascomús; ArgentinaFil: Silva, Andrea Paula. Dirección Nacional del Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr.C.G.Malbran". Instituto Nacional de Epidemiologia; ArgentinaFil: Ángel, Sergio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Simplified model of battery energy-stored quasi-Z-source inverter-based photovoltaic power plant with Twofold energy management system

The use of a battery energy-stored quasi-Z-source inverter (BES-qZSI) for large-scale PV power plants exhibits promising features due to the combination of qZSI and battery as energy storage system, such as single-stage power conversion (without additional DC/DC boost converter), improvements in the output waveform quality (due to the elimination of switching dead time), and continuous and smooth delivery of energy to the grid (through the battery energy storage system). This paper presents a new simplified model of a BES-qZSI to represent the converter dynamics with sufficient accuracy while using a less complex model than the detailed model (including the modelling of all switches and switching pulses). It is based on averaged values of the variables, voltage/current sources, and the same control circuit than the detailed model, except for the switching pulses generation. The simplified model enables faster time-domain simulation and is useful for control design and dynamic analysis purposes. Additionally, an energy management system has been developed to govern the power supply to grid under two possible scenarios: 1) System operator command following; or 2) economic dispatch of the stored energy. The results obtained from simulations and experimental hardware-in-the-loop (HIL) setup for different operating conditions of the grid-connected large-scale PV power plant with battery energy storage under study demonstrate the validity of the proposed simplified model to represent the dynamics of the converter and PV power plant for steady-state stability studies, long-term simulations, or large electric power systems. © 2021 The AuthorsThis work was partially supported by the Spain's Ministerio de Ciencia, Innovaci?n y Universidades (MCIU), Agencia Estatal de Investigaci?n (AEI), and Fondo Europeo de Desarrollo Regional (FEDER) Uni?n Europea (UE) (grant number RTI2018-095720-B-C32), by the Federal Center for Technological Education of Minas Gerais, Brazil (process number 23062?010087/2017-51) and by the National Council of Technological and Scientific Development (CNPq-Brazil

Modelo predictor de precios atípicos en importaciones de México

El propósito general del PAP “Programa de Modelación Matemática para el Desarrollo de Planes y Proyectos de Negocio” es que a partir de una base de datos de importaciones del estado de Jalisco se busca generar un modelo de predicción mediante caracteres y precios, para lograr identificar precios atípicos dentro de las importaciones. Con la base de datos que cuenta con más de un millón de registros, se pueden observar datos importantes, como la descripción que cada uno de los importadores deben llenar acerca de su producto. Este apartado de la base de datos llamado descripción no está obligada a seguir ningún formato ni palabras específicas, por lo que el grado de complejidad del modelo buscado es mayor al tener que realizar una limpieza exhaustiva de la base de datos.ITESO, A.C