Heat and moisture budgets from airborne measurements and high-resolution model simulations

High-resolution simulations with a mesoscale model are performed to estimate heat and moisture budgets of a well-mixed boundary layer. The model budgets are validated against energy budgets obtained from airborne measurements over heterogeneous terrain in Western Germany. Time rate of change, vertical divergence, and horizontal advection for an atmospheric column of air are estimated. Results show that the time trend of specific humidity exhibits some deficiencies, while the potential temperature trend is matched accurately. Furthermore, the simulated turbulent surface fluxes of sensible and latent heat are comparable to the measured fluxes, leading to similar values of the vertical divergence. The analysis of different horizontal model resolutions exhibits improved surface fluxes with increased resolution, a fact attributed to a reduced aggregation effect. Scale-interaction effects could be identified: while time trends and advection are strongly influenced by mesoscale forcing, the turbulent surface fluxes are mainly controlled by microscale processes

Protein-Binding Microarray Analysis of Tumor Suppressor AP2α Target Gene Specificity

Cheap and massively parallel methods to assess the DNA-binding specificity of transcription factors are actively sought, given their prominent regulatory role in cellular processes and diseases. Here we evaluated the use of protein-binding microarrays (PBM) to probe the association of the tumor suppressor AP2α with 6000 human genomic DNA regulatory sequences. We show that the PBM provides accurate relative binding affinities when compared to quantitative surface plasmon resonance assays. A PBM-based study of human healthy and breast tumor tissue extracts allowed the identification of previously unknown AP2α target genes and it revealed genes whose direct or indirect interactions with AP2α are affected in the diseased tissues. AP2α binding and regulation was confirmed experimentally in human carcinoma cells for novel target genes involved in tumor progression and resistance to chemotherapeutics, providing a molecular interpretation of AP2α role in cancer chemoresistance. Overall, we conclude that this approach provides quantitative and accurate assays of the specificity and activity of tumor suppressor and oncogenic proteins in clinical samples, interfacing genomic and proteomic assays

Nuclear factor I genomic binding associates with chromatin boundaries

BACKGROUND: The Nuclear Factor I (NFI) family of DNA binding proteins (also called CCAAT box transcription factors or CTF) is involved in both DNA replication and gene expression regulation. Using chromatin immuno-precipitation and high throughput sequencing (ChIP-Seq), we performed a genome-wide mapping of NFI DNA binding sites in primary mouse embryonic fibroblasts. RESULTS: We found that in vivo and in vitro NFI DNA binding specificities are indistinguishable, as in vivo ChIP-Seq NFI binding sites matched predictions based on previously established position weight matrix models of its in vitro binding specificity. Combining ChIP-Seq with mRNA profiling data, we found that NFI preferentially associates with highly expressed genes that it up-regulates, while binding sites were under-represented at expressed but unregulated genes. Genomic binding also correlated with markers of transcribed genes such as histone modifications H3K4me3 and H3K36me3, even outside of annotated transcribed loci, implying NFI in the control of the deposition of these modifications. Positional correlation between + and - strand ChIP-Seq tags revealed that, in contrast to other transcription factors, NFI associates with a nucleosomal length of cleavage-resistant DNA, suggesting an interaction with positioned nucleosomes. In addition, NFI binding prominently occurred at boundaries displaying discontinuities in histone modifications specific of expressed and silent chromatin, such as loci submitted to parental allele-specific imprinted expression. CONCLUSIONS: Our data thus suggest that NFI nucleosomal interaction may contribute to the partitioning of distinct chromatin domains and to epigenetic gene expression regulation. NFI ChIP-Seq and input control DNA data were deposited at Gene Expression Omnibus (GEO) repository under accession number GSE15844. Gene expression microarray data for mouse embryonic fibroblasts are on GEO accession number GSE15871

Анализ поля напряжений и симметрии оси сжатия ГЦК-монокристаллов

Subject of this work is the recently introduced extended Representative Interactive Flamelet (RIF) model for multiple injections. First, the two-dimensional laminar flamelet equations, which can describe the transfer of heat and mass between two-interacting mixture fields, are presented. This is followed by a description of the various mixture fraction and mixture fraction variance equations that are required for the RIF model extension accounting for multiple injection events. Finally, the modeling strategy for multiple injection events is described: Different phases of combustion and interaction between the mixture fields resulting from different injections are identified. Based on this, the extension of the RIF model to describe any number of injections is explained. Simulation results using the extended RIF model are compared against experimental data for a Common-Rail DI Diesel engine that was operated with three injection pulses. Simulated pressure curves, heat release rates, and pollutant emissions are found to be in good agreement with corresponding experimental data. For the pilot injection and the main or post injection, respectively, different ignition phenomena are pointed out and the influence of the scalar dissipation rate on these ignition phenomena is detailly investigated. 2009 SAE International

Entwicklung eines modalen Modells zur Beschreibung der Chemie und Physik von Wolken und Aerosolen und dessen Implementierung in das EURAD-Modellsystem zur Beschreibung aerosolbedingter Modifikationen des aktinischen Flusses Abschlussbericht

In Kooperation mit dem Ford Forschungszentrum Aachen (FFA) wurde eine trimodale Version des Modalen Aerosol-Dynamik Modells fuer Europa (MADE) in das EURAD-Modellsystem implementiert und weiterentwickelt. Weiterhin wurden Module fuer die Wechselwirkungen von Aerosolen und Wolken sowie zur Bildung von sekundaerem organischen Aerosol implementiert. Die Funktionsfaehigkeit dieser Module wurde mit Modellrechnungen ueberprueft. Dem Wolkenmodul zugrundeliegende Annahmen konnten in Zusammenarbeit mit dem Institut fuer Troposphaerenforschung (IFT, Leipzig) und der Universitaet Cottbus (BTU) ueberprueft werden. Durch Vergleiche zwischen prognostizierten PM_1_0-Konzentrationen und Messungen an Stationen des Landesumweltamtes Nordrhein-Westfalen wurde das Aerosol-Dynamik Modell fuer Episoden im Sommer und Winter 1997 validiert. Die Validierung zeigt, dass die prognostizierten Aerosolkonzentrationen im Gebiet von Nordrhein Westfalen groesstenteils innerhalb der Toleranzen liegen, die von der Europaeischen Union als Bewertungskriterien fuer Luftschadstoffmodelle vorgegeben wurden. Eine weitere Validierung, die ueber das Gebiet von Nordrhein-Westfalen hinaus reicht, wurde mit Hilfe von Messungen der Sulfat- und Schwebstaubkonzentrationen an EMEP Stationen durchgefuehrt. Damit liegt ein Aerosol-Dynamik-Modell vor, das bereits routinemaessig innerhalb des EURAD Modellsystems eingesetzt wird und sich fuer den Einsatz bei der Umsetzung von Richtlinien der EU zur Luftqualitaet eignet. Vorbereitende Massnahmen zur Beschreibung aerosolbedingter Modifikationen des aktinischen Flusses wurden durchgefuehrt. Ihre Umsetzung erscheint zum gegenwaertigen Zeitpunkt aufgrund von technischen Problemen bei der numerischen Simulation der chemischen Zusammensetzung und Groessenverteilung von Wolkentropfen sowie des Kohlenstoffanteils von Aerosolpartikeln verfrueht. (orig.)In cooperation with the Ford Research Center Aachen a trimodal version of the Modal Aerosol Dynamics Model for Europe (MADE) has been developed further and implemented into the EURAD model system. Model components for aerosol cloud interactions and secondary organic aerosols have implemented. Parameterizations of aerosol cloud interactions have verified in cooperation with the Institut fuer Troposphaerenforschung (IFT) and the university of Cottbus (BTU). Model results for episodes in summertime and wintertime 1997 have compared with measurements of PM_1_0-concentrations from the department of the environment of Northrine-Westfalia. Inside the area of Northrine-Westfalia the modelled PM_1_0-concentrations are largely in agreement with the assessment principles for air quality models recommended by the European Union. Modelled sulphate and TSP-concentrations have compared with measurements at stations from the EMEP network. The developed aerosol dynamics model is useful for the realization and control of air quality directives passed by the European Union. The numerical simulation of modifications of the Actinic flux caused by aerosols have prepared. Technical problems remain concerning the numerical description of the size-composition distribution of cloud droplets. Furthermore the determination of the soot fraction of aerosol particles is very uncertain at the moment. For this reasons an implementation of the numerical simulation of modifications of the Actinic flux caused by aerosol particles have put on the back burner. (orig.)SIGLEAvailable from TIB Hannover: F02B982+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman