555 research outputs found

    European air quality maps 2005 including uncertainty analysis

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    The objective of this report is (a) the updating and refinement of European air quality maps based on annual statistics of the 2005 observational data reported by EEA Member countries in 2006, and (b) the further improvement of the interpolation methodologies. The paper presents the results achieved and an uncertainty analysis of the interpolated maps and builds upon earlier reports from Horalék et al. (2005; 2007)

    Myeloid heterogeneity in kidney disease as revealed through single cell RNA sequencing

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    Kidney disease represents a global health burden of increasing prevalence and is an independent risk factor for cardiovascular disease. Myeloid cells are a major cellular compartment of the immune system; they are found in the healthy kidney and in increased numbers in the damaged and/or diseased kidney, where they act as key players in the progression of injury, inflammation, and fibrosis. They possess enormous plasticity and heterogeneity, adopting different phenotypic and functional characteristics in response to stimuli in the local milieu. Although this inherent complexity remains to be fully understood in the kidney, advances in single-cell genomics promise to change this. Specifically, single-cell RNA sequencing (scRNA-seq) has had a transformative effect on kidney research, enabling the profiling and analysis of the transcriptomes of single cells at unprecedented resolution and throughput, and subsequent generation of cell atlases. Moving forward, combining scRNA- and single-nuclear RNA-seq with greater-resolution spatial transcriptomics will allow spatial mapping of kidney disease of varying etiology to further reveal the patterning of immune cells and nonimmune renal cells. This review summarizes the roles of myeloid cells in kidney health and disease, the experimental workflow in currently available scRNA-seq technologies, and published findings using scRNA-seq in the context of myeloid cells and the kidney

    Modelling and interpretation of turbulent fluxes in katabatic flows : applications to glaciers and the Greenland ice sheet

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    The aim of this thesis is to improve our understanding of the processes by which heat energy from the atmosphere is transferred through the ABL to glacier surfaces. This is approached from a modelling perspective where appropriate turbulence closure models are developed, interpreted, and applied to both glaciers and the Greenland ice sheet. The first part of this thesis involves the development of such a turbulent closure model which can be used to simulate katabatic flows and the turbulent fluxes associated with them. Knowledge acquired from these simulations is then used to improve the interpretation of meteorological measurements made on glaciers, leading to better estimates of these turbulent fluxes. The second part of this thesis applies the turbulence closure model to a 3-D boundary layer model of the Greenland ice sheet. This boundary layer model is forced by ECMWF analysis data and simulations are compared to observed meteorological variables of wind, temperature and specific humidity, Experiments with the 3-D model are then carried out to determine the sensitivity of the surface energy flux components to an increase in free atmospheric temperature. The results show that more than half of the increase in the surface energy flux is the result of increases in the turbulent heat fluxes and that albedo feedback can play a significant role in amplifying this increase. In addition, it is pointed out that the climate sensitivity of 2 m temperature is far less than unity as a result of the proximity of the melting ice surface. This is important for other climate sensitivity experiments carried out using 2 m temperature as a forcing parameter

    Neural Filters for Jet Analysis

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    We study the efficiency of a neural-net filter and deconvolution method for estimating jet energies and spectra in high-background reactions such as nuclear collisions at the relativistic heavy-ion collider and the large hadron collider. The optimal network is shown to be surprisingly close but not identical to a linear high-pass filter. A suitably constrained deconvolution method is shown to uncover accurately the underlying jet distribution in spite of the broad network response. Finally, we show that possible changes of the jet spectrum in nuclear collisions can be analyzed quantitatively, in terms of an effective energy loss with the proposed method. {} {Dong D W and Gyulassy M 1993}{Neural filters for jet analysis} {(LBL-31560) Physical Review E Vol~47(4) pp~2913-2922}Comment: 21 pages of Postscript, (LBL-31560

    Analysis of Dynamic Brain Imaging Data

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    Modern imaging techniques for probing brain function, including functional Magnetic Resonance Imaging, intrinsic and extrinsic contrast optical imaging, and magnetoencephalography, generate large data sets with complex content. In this paper we develop appropriate techniques of analysis and visualization of such imaging data, in order to separate the signal from the noise, as well as to characterize the signal. The techniques developed fall into the general category of multivariate time series analysis, and in particular we extensively use the multitaper framework of spectral analysis. We develop specific protocols for the analysis of fMRI, optical imaging and MEG data, and illustrate the techniques by applications to real data sets generated by these imaging modalities. In general, the analysis protocols involve two distinct stages: `noise' characterization and suppression, and `signal' characterization and visualization. An important general conclusion of our study is the utility of a frequency-based representation, with short, moving analysis windows to account for non-stationarity in the data. Of particular note are (a) the development of a decomposition technique (`space-frequency singular value decomposition') that is shown to be a useful means of characterizing the image data, and (b) the development of an algorithm, based on multitaper methods, for the removal of approximately periodic physiological artifacts arising from cardiac and respiratory sources.Comment: 40 pages; 26 figures with subparts including 3 figures as .gif files. Originally submitted to the neuro-sys archive which was never publicly announced (was 9804003

    FAIRMODE: A FORUM FOR AIR QUALITY MODELLING IN EUROPE

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    FAIRMODE (Forum for AIR quality MODelling in Europe) is an air quality modelling network that was established as a joint initiative of the European Environment Agency (EEA) and European Commission’s Joint Research Centre (JRC). In a common effort EEA and JRC aim at responding to the requirements of the new Air Quality Directive, with particular focus on the introduction of modelling as a necessary tool for air quality assessment and air quality management. The main aim of the modelling network is to bring together air quality modellers and model users in order to promote and support harmonised use of modelling for the assessment of air quality by EU and EEA member countries. The network will thus encourage synergy – at a local, national and European level - through the development and implementation of a common infrastructure based on best practices for reporting and storing information relevant to air quality modelling. A major objective of the FAIRMODE initiative is to provide guidance to present and future air quality model users in EEA’s EIONET partnership network. FAIRMODE also aims to enhance awareness of model usefulness, reliability and accuracy through model validation and intercomparison exercises at a national or European level. The JRC has taken on a leading role in the co-ordination of the latter activities gaining from its experience in leading the “Eurodelta” and “CityDelta” intercomparison exercises. A centralised web portal has been created in support of FAIRMODE, which is currently being used for internal communication purposes of the network participants, but will also provide the means for exchange of relevant material and experiences between all interested modellers and model users. The initial activities of the network will be organised by two main Work Groups, focusing on the preparation of a Guidance Document for model use and on model QA/QC procedures (input data, other uncertainties) respectively. The progress of the preparation of these documents as well as of the rest of the regular activities of the network will be reviewed and discussed within the frame of annual Plenary meetings and Steering Committee meetings

    Basal type I interferon signaling has only modest effects on neonatal and juvenile hematopoiesis

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    Type I interferon (IFN-1) regulates gene expression and hematopoiesis both during development and in response to inflammatory stress. We previously showed that during development in mice, hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) induce IFN-1 target genes shortly before birth. This coincides with the onset of a transition to adult hematopoiesis, and it drives the expression of genes associated with antigen presentation. However, it is not clear whether perinatal IFN-1 modulates hematopoietic output, as has been observed in contexts of inflammation. We have characterized hematopoiesis at several different stages of blood formation, from HSCs to mature blood cells, and found that loss of the IFN-1 receptor (IFNAR1) leads to depletion of several phenotypic HSC and MPP subpopulations in neonatal and juvenile mice. Committed lymphoid and myeloid progenitor populations expand simultaneously. These changes had a surprisingly little effect on the production of more differentiated blood cells. Cellular indexing of transcriptomes and epitopes by sequencing resolved the discrepancy between the extensive changes in progenitor numbers and modest changes in hematopoiesis, revealing stability in most MPP populations in Ifnar1-deficient neonates when the populations were identified based on gene expression rather than surface marker phenotype. Thus, basal IFN-1 signaling has only modest effects on hematopoiesis. Discordance between transcriptionally and phenotypically defined MPP populations may affect interpretations of how IFN-1 shapes hematopoiesis in other contexts, such as aging or inflammation

    Consolidated science and user requirements for a next generation gravity field mission

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    In an internationally coordinated initiative among the main user communities of gravity field products the science and user requirements for a future gravity field mission constellation (beyond GRACE-FO) have been reviewed and defined. This activity was realized as a joint initiative of the IAG (International Association of Geodesy) Sub-Commissions 2.3 and 2.6, the GGOS (Global Geodetic Observing System) Working Group on Satellite Missions, and the IUGG (International Union of Geodesy and Geophysics). After about one year of preparation, in a user workshop that was held in September 2014 consensus among the user communities of hydrology, ocean, cryosphere, solid Earth and atmosphere on consolidated science requirements could be achieved. The consolidation of the user requirements became necessary, because several future gravity field studies have resulted in quite different performance numbers as a target for a future gravity mission (2025+). Based on limited number of mission scenarios which took also technical feasibility into account, a consolidated view on the science requirements among the international user communities was derived, research fields that could not be tackled by current gravity missions have been identified, and the added value (qualitatively and quantitatively) of these scenarios with respect to science return has been evaluated. The resulting document shall form the basis for further programmatic and technological developments. In this contribution, the main results of this initiative will be presented. An overview of the specific requirements of the individual user groups, the consensus on consolidated requirements as well as the new research fields that have been identified during this process will be discussed
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