Metric of a Slow Rotating Body with Quadrupole Moment from the Erez-Rosen Metric

A metric representing a slowly rotating object with quadrupole moment is obtained using a perturbation method to include rotation into the weak limit of the Erez-Rosen metric. This metric is intended to tackle relativistic astrometry and gravitational lensing problems in which a quadrupole moment has to be taken into account

A Visualization of Null Geodesics for the Bonnor Massive Dipole

In this work we simulate null geodesics for the Bonnor massive dipole metric by implementing a symbolic-numerical algorithm in Sage and Python. This program is also capable of visualizing in 3D, in principle, the geodesics for any given metric. Geodesics are launched from a common point, collectively forming a cone of light beams, simulating a solid-angle section of a point source in front of a massive object with a magnetic field. Parallel light beams also were considered, and their bending due to the curvature of the space-time was simulated.Comment: 9 pages, 5 figures, Presented at XIX Simposio Internacional de M\'etodos Matem\'aticos Aplicados a las Ciencias (19th International Symposium of Mathematical Methods Applied to Sciences, XIX-SIMMAC

Solar activity and climate in Central America

Artículo científico -- Universidad de Costa Rica. Centro de Investigaciones Geofísicas, 2000Se analizaron los posibles efectos de la actividad solar en la temperatura superficial del aire y precipitación en Centro América. La correlación entre las series de manchas solares y las variables climáticas mencionadas es pobre. No obstante, se observó una tendencia creciente en los datos durante el periodo considerado. Usando el análisis de Fourier se encontraron picos de frecuencia aproximadamente a los 11 años y 5 años. Esto sugiere que la actividad solar puede ser un factor que afecta las variables climáticas.Possible effects of solar activity on the records of air surface temperature and rainfall in Central America are analysed. The correlation between the series of sunspot numbers, surface air temperature and precipitation, is poor. However an increasing tendency in the series is observed for the time period considered. Using Fourier analysis, frequency peaks were found close to 11 years and 5 years for both solar and climate data. This suggest that solar activity might be a factor which affects the climate’s variables.Universidad de Costa Rica, Centro de Investigaciones GeofísicasUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI

Analysis of the common genetic component of large-vessel vasculitides through a meta- Immunochip strategy

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P?=?7.54E-07; ORGCA?=?1.19, ORTAK?=?1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA?=?5.52E-04, ORGCA?=?1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus

A genome-wide association study identifies risk alleles in plasminogen and P4HA2 associated with giant cell arteritis

Giant cell arteritis (GCA) is the most common form of vasculitis in individuals older than 50 years in Western countries. To shed light onto the genetic background influencing susceptibility for GCA, we performed a genome-wide association screening in a well-powered study cohort. After imputation, 1,844,133 genetic variants were analysed in 2,134 cases and 9,125 unaffected controls from ten independent populations of European ancestry. Our data confirmed HLA class II as the strongest associated region (independent signals: rs9268905, P = 1.94E-54, per-allele OR = 1.79; and rs9275592, P = 1.14E-40, OR = 2.08). Additionally, PLG and P4HA2 were identified as GCA risk genes at the genome-wide level of significance (rs4252134, P = 1.23E-10, OR = 1.28; and rs128738, P = 4.60E-09, OR = 1.32, respectively). Interestingly, we observed that the association peaks overlapped with different regulatory elements related to cell types and tissues involved in the pathophysiology of GCA. PLG and P4HA2 are involved in vascular remodelling and angiogenesis, suggesting a high relevance of these processes for the pathogenic mechanisms underlying this type of vasculitis

Monitoreo forestal con sensoramiento remoto en el marco del cambio climático

The research of the effects of the climate change is one of the biggest challenges for the humanity. Nowadays, there is a debate about the amount and the flow of the carbon reservation in the forests. As soon as, these flows reduces the concentrations of the CO2 in the atmosphere. In this context, the UN Framework Convention on Climate Change’s deals with concerted actions in an international level to reduce the emissions of CO2 and increase carbon (C) sequestration through the human intervention, including any activity related with the forest management. However, the forestry and the forest management have been recognized as activities which are extremely difficult to established a quantative control of the contributions induced by activities of the human been relative to the emissions or the carbon sequestration to the atmosphere. In the different conventions and agreements, for example, the agreements Marrakech (2001), only the reforestation was included as an eligible action in the context of the Clean Development Mechanism (CDM). After tough negotiations, and with the passage of time, a range of forest activities were incorporated, culminating with the processes of REDD and REDD+, for example, the financial compensation for the successful national arrangements reducing the deforestation and the forest degradation. It was thought then, about the necessity of counting with effective and reliable systems of tracing. Through the reports of Measuring, Reporting and Verification (MRV) has been established and accepted as an standard framework for monitoiring processes, consisting in a resourse inventory (the tradional forest inventories) as a key component. This work approaches and analyzes the challenges of the remote sensing in the context of the projects related with forest and MRV. In addition, it becomes an approach of the necessity of studying the seasonal changes of the vegetation in Costa Rica and how this variations can affect the results of the projects of mapping the forest ecosystems.Recibido: 11/09/2014 Aceptado: 30/06/2016La investigación de los efectos del cambio climático es uno de los mayores desafíos para la humanidad. En la actualidad, se debate la cantidad y los flujos de las reservas de carbono en los bosques. En cuanto a estos flujos reducen las concentraciones de CO2 en la atmósfera. En este contexto, la Convención Marco de las Naciones Unidas sobre el Cambio Climático (CMNUCC) se ocupa de las medidas concertadas a nivel internacional para reducir las emisiones de CO2 y aumentar el secuestro de carbono (C) a través de la intervención humana, incluyendo todas aquellas actividades relacionadas con el manejo y gestión forestal. Sin embargo, la silvicultura y el manejo de bosques han sido reconocidas como actividades donde es extremadamente difícil establecer un control cuantitativo de los aportes inducidos por las actividades del ser humano relativas a la emisión o secuestro de C a la atmósfera. En las diferentes convenciones y acuerdos, por ejemplo, los acuerdos de Marrakech (2001), solo la re-forestación se incluyó como acciones subvencionables en el contexto del mecanismo de desarrollo limpio (MDL). Luego de arduas negociaciones y con el transcurrir del tiempo, se fueron incorporando una amplia gama de actividades forestales, que culminaron con los procesos de REDD y REDD+. Dentro de REDD+, por ejemplo, se logró la compensación financiera para las medidas nacionales exitosas que reducen la deforestación y la degradación forestal. Se pensó, entonces, en la necesidad de contar con sistemas eficaces y fiables de seguimiento. Mediante los informes de medición-reporte y verificación (MRV) se ha establecido y aceptado como un marco estándar para procesos de monitoreo, que consiste en un inventarios de recursos (tradicionalmente inventarios forestales) como un componente clave. En este trabajo se aborda y analizan los retos del sensoramiento remoto en el contexto de los proyectos relacionados con los bosques y el MRV. Se hace, además, un abordaje de la necesidad de estudiar los cambios estacionales de la vegetación en Costa Rica y de cómo estas variaciones pueden afectar los resultados de los proyectos de mapeo de ecosistemas boscosos

Erratum: Corrigendum: Analysis of the common genetic component of large-vessel vasculitides through a meta-Immunochip strategy

Giant cell arteritis (GCA) and Takayasu’s arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/ MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P = 7.54E-07; ORGCA = 1.19, ORTAK = 1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA = 5.52E-04, ORGCA = 1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus

Corrigendum: Analysis of the common genetic component of large-vessel vasculitides through a meta-Immunochip strategy (Scientific Reports (2017) 7 (43953) DOI: 10.1038/srep43953)

Giant cell arteritis (GCA) and Takayasu\u2019s arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/ MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P = 7.54E-07; ORGCA = 1.19, ORTAK = 1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA = 5.52E-04, ORGCA = 1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus