272 research outputs found

    Gases reactivos y calidad del aire a escala global

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    Presentación de la clase impartida en el Observatorio Atmosférico de Izaña, el 18 de junio de 2016, con motivo del curso "Conceptos Básicos de Composición Atmosférica

    La periodontitis como factor de riesgo en los pacientes con cardiopatía isquémica

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    La patología cardiovascular y en especial la cardiopatía isquémica (CI) se encuentran entre las principales causas de muerte en el mundo occidental. Recientemente se ha incrementado el interés en investigar la relación entre la cardiopatía isquémica y diversas patologías infecciosas como desencadenantes de la misma, como se ha observado con la Clamydia pneumoniae y el Helicobacter pylori. La periodontitis también se ha relacionado con el incremento de riesgo de aparición de enfermedad coronaria, debido a que ambas patologías presentan algunas características comunes como la edad, el sexo y el hábito tabáquico entre otras. Existen muchas similitudes entre la patología vascular inducida por bacterias y la historia natural de la aterogénesis. El principal mecanismo de acción entre la periodontitis y la cardiopatía isquémica radica en el efecto que las bacterias y sus endotoxinas producen sobre las reacciones inflamatorias, los procesos hemostáticos y las alteraciones en el metabolismo de los lípidos. Sin embargo existen autores que defienden que la periodontitis es un epifenómeno y que son necesarios mas estudios para determinar la relación causa-efecto entre estas dos patologías multifactoriales.Cardiovascular disease, and particularly ischemic heart disease (IHD), constitutes one of the principal causes of mortality in the western world. Interest has recently increased in the relationship between IHD and different infectious processes as triggering factors of the former, such as Chlamydia pneumoniae and Helicobacter pylori infection. Periodontitis has also been related to an increased risk of coronary disease, since both disorders share common characteristics such as patient age and sex, and a smoking habit, among other aspects. There are many similarities between vascular pathology induced by bacteria and the natural history of atherogenesis. The principal mechanism of action underlying periodontitis and IHD centers on the effect of bacteria and their endotoxins upon inflammatory reaction, hemostasia and lipid metabolic alterations. However, some authors are of the opinion that periodontitis constitutes an epiphenomenon, and that further studies are needed to clarify the cause-effect relation between these two multifactor pathologies

    The inner view of NGC 1052 using multiple X-ray observations

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    In this paper, we make a multi-epoch analysis of NGC 1052, one of the prototypical LLAGN, using XMM-Newton, Suzaku and NuSTAR observations, taken from 2001 to 2017. This is the first time that results from NuSTAR observations are reported for NGC 1052. On the technical aspects, we found a wavelength-dependent calibration issue between simultaneous XMM-Newton and NuSTAR spectra. It is described by a change on the photon index of ΓNuSTARΓXMMNewton=0.17±0.04\rm{ \Gamma_{NuSTAR}- \Gamma_{XMM-Newton}=0.17\pm0.04}. We use ancillary Chandra data to decontaminate the nuclear spectrum from circumnuclear contributors. We find that two baseline models can fit the broad (0.5-50 keV) X-ray spectrum of the source. One consists of a power-law like continuum which is absorbed by a uniform absorber, reflection from neutral material, and a separate power-law component in the soft band. The second model presents a clumpy absorber. The reflection component is still present, but not the soft band power-law. Instead, absorption by a warm absorber is necessary to fit the spectra. This is the first time that a reflection component is established in this object, thanks to high energy data from NuSTAR. This component is constant in flux and shape, supporting the idea that is produced away from the central source (probably the torus). We find flux, spectral slope and absorption variations on timescales of months to years. We also find that a patchy-absober can explain the behaviour of this source better as it is \sim 200 times more likely than the uniform absober while it yields to smaller intrinsic variations.Comment: 11 pages, 6 figures, 2 tables. Accepted for publication in MNRA

    Parte todo de una fracción para desarrollar la competencia argumentativa en estudiantes de cuarto grado

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    La investigación “Parte todo de una fracción para desarrollar la competencia argumentativa en estudiantes de cuarto grado” tuvo como objetivo general determinar el desarrollo de la competencia argumentativa en estudiantes de cuarto grado, a través del fortalecimiento de sus habilidades cognitivo lingüísticas, mientras resuelven una serie de tareas, desde la relación “parte todo”. El enfoque metodológico fue cualitativo, con corte descriptivo; se utilizaron tres instrumentos para la recolección de la información: Instrumento 1 Indagación, instrumento 2 Unidad Didáctica e instrumento 3 Prueba Final. En el análisis final, se evidenció en las respuestas de los estudiantes un uso más frecuente de habilidades cognitivo lingüísticas como explicación, justificación y argumentación, así mismo se notó un aumento en los argumentos ubicados en los niveles 2 y 3. Según los resultados, se puede pensar que al fortalecer las habilidades cognitivo lingüísticas de los estudiantes, es posible perfeccionar su competencia argumentativa.The research "part of a fraction to develop argumentative competition in fourth grade students" had as a general objective to determine the development of argumentative competition in fourth grade students, through the Strengthening their cognitive linguistic skills, while solving a series of tasks, from the "part everything" relationship. The methodological approach was qualitative, with descriptive, three instruments were used for the collection of information: Instrument 1 Inquiry, Instrument 2 didactic Unit and instrument 3 Final Test. In the final analysis, it was evident in the responses of the students a more frequent use of linguistic cognitive skills as explanation, justification and argumentation, also noticed an increase in the arguments located in Levels 2 and 3. According to the results, it is possible to think that by strengthening the cognitive linguistic skills of the students, it is able to improve their argumentative competence

    Design and evaluation of a portable frequency comb-referenced laser heterodyne radiometer

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    In this paper, we present the design of a laser heterodyne radiometry instrument that combines, for the first time, frequency comb calibration and a remarkably high level of portability. A design that can, therefore, be more than capable of addressing the current need for accurate ground-based greenhouse gases monitoring in urban areas and other emission hot spots. Indeed, the compact, battery-powered system allows the acquisition of atmospheric spectral characterizations, at any location, without restrictions. As its most prominent feature, the system is equipped with an electro-optic frequency comb reference that provides a set of calibration ticks from which an accurate characterization of the absorption line shape can be obtained. Besides this, the spectrometer has been designed to promptly switch between traditional operation and wavelength modulation, so the performance of future inversion models may benefit greatly by this complementary data. The system has been tested in different locations in the Madrid region (Spain), where measurements have been carried out under a wide variety of conditions. Here, a set of highly representative results is presented clearly illustrating the capabilities of the developed system.This project has received funding from the EU H2020 Consumerdriven demands to reframe farming systems project under Grant Agreement 101000216, and from the Agencia Estatal de InvestigaciÓn under Grant Project TED2021-131695B-100

    Report on how EIONET and EEA can contribute to the urban in situ requirements of a future Copernicus anthropogenic CO2 observing system

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    This report provides a technical review of CO2 and CH4 emissions monitoring methods based on surface mixing ratio measurements, total column mixing ratio measurements and flux measurements. The review demonstrated that all these measurements would fulfil respective in situ requirements of the Copernicus CO2 MVS capacity, contributing to the validation of space observations in and around cities and/or the system’s city-scale emissions estimates. The review furthermore elaborated on the benefits to climate change mitigation monitoring in the respective cities and how these methods could be implemented to monitor local emissions.Negotiated procedure No EEA/IDM/R0/17/008. Services supporting the European Environment Agency’s (EEA) crosscutting coordination of the Copernicus In Situ Componen

    Radiative forcing under mixed aerosol conditions

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    The mixture of mineral dust with biomass burning or urban-industrial aerosols presents significant differences in optical properties when compared to those of the individual constituents, leading to different impacts on solar radiation levels. This effect is assessed by estimating the direct radiative forcing (ΔF) of these aerosols from solar flux models using the radiative parameters derived from the Aerosol Robotic Network (AERONET). These data reveal that, in oceanic and vegetative covers (surface albedo (SA) 0.30 are not present in East Asia region. At the bottom of atmosphere (BOA) the maximum ΔF values are associated with the highest AOD levels obtained for the mixture of mineral dust and biomass burning aerosols (−130 ± 44 Wm−2 with AOD = 0.8 ± 0.4 for SA < 0.30).Support for this study was given by Spanish Ministry of Education and Science, projects CGL2005‐03428‐C04‐02, CGL2007‐66477‐C02‐02/CLI, PI042005/033, and CGL2008‐04740/CLI

    Quality assessment of ozone total column amounts as monitored by ground-based solar absorption spectrometry in the near infrared (> 3000 cm−1)

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    This study examines the possibility of ground-based remote-sensing ozone total column amounts (OTC) from spectral signatures at 3040 and 4030 cm−1. These spectral regions are routinely measured by the NDACC (Network for the Detection of Atmospheric Composition Change) ground-based FTIR (Fourier transform infraRed) experiments. In addition, they are potentially detectable by the TCCON (Total Carbon Column Observing Network) FTIR instruments. The ozone retrieval strategy presented here estimates the OTC from NDACC FTIR high-resolution spectra with a theoretical precision of about 2 and 5% in the 3040 and 4030 cm−1 regions, respectively. Empirically, these OTC products are validated by inter-comparison to FTIR OTC reference retrievals in the 1000 cm−1 spectral region (standard reference for NDACC ozone products), using an 8-year FTIR time series (2005–2012) taken at the subtropical ozone supersite of the Izaña Atmospheric Observatory (Tenerife, Spain). Associated with the weaker ozone signatures at the higher wave number regions, the 3040 and 4030 cm−1 retrievals show lower vertical sensitivity than the 1000 cm−1 retrievals.The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 284421 (NORS project) and from the Ministerio de Economía and Competitividad from Spain for the project CGL2012-37505 (NOVIA project). M. Schneider and Y. González are supported by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 256961 and E. Sepúlveda is supported by the NOVIA Project

    Investigating the long-term evolution of subtropical ozone profiles applying ground-based FTIR spectrometry

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    This study investigates the long-term evolution of subtropical ozone profile time series (1999–2010) obtained from ground-based FTIR (Fourier Transform InfraRed) spectrometry at the Izaña Observatory ozone super-site. Different ozone retrieval strategies are examined, analysing the influence of an additional temperature retrieval and different constraints. The theoretical assessment reveals that the FTIR system is able to resolve four independent ozone layers with a precision of better than 6% in the troposphere and of better than 3% in the lower, middle and upper stratosphere. This total error includes the smoothing error, which dominates the random error budget. Furthermore, we estimate that the measurement noise as well as uncertainties in the applied atmospheric temperature profiles and instrumental line shape are leading error sources. We show that a simultaneous temperature retrieval can significantly reduce the total random errors and that a regular determination of the instrumental line shape is important for producing a consistent long-term dataset. These theoretical precision estimates are empirically confirmed by daily intercomparisons with Electro Chemical Cell (ECC) sonde profiles. In order to empirically document the long-term stability of the FTIR ozone profile data we compare the linear trends and seasonal cycles as obtained from the FTIR and ECC time series. Concerning seasonality, in winter both techniques observe stratospheric ozone profiles that are typical middle latitude profiles (low tropopause, low ozone maximum concentrations) and in summer/autumn profiles that are typical tropical profiles (high tropopause, high maximum concentrations). The linear trends estimated from the FTIR and the ECC datasets agree within their error bars. For the FTIR time series, we observe a significant negative trend in the upper troposphere/lower stratosphere of about −0.2%yr−1 and a significant positive trend in the middle and upper stratosphere of about +0.3%yr−1 and +0.4%yr−1, respectively. Identifying such small trends is a difficult task for any measurement technique. In this context, super-sites applying different techniques are very important for the detection of reliable ozone trends
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