272 research outputs found

    Source-receptor matrix calculation with a Source-receptor matrix calculation with a backward mode

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    International audienceThe possibility to calculate linear-source receptor relationships for the transport of atmospheric trace substances with a Lagrangian particle dispersion model (LPDM) running in backward mode is shown and presented with many tests and examples. The derivation includes the action of sources and of any first-order processes (transformation with prescribed rates, dry and wet deposition, radioactive decay, ...). The backward mode is computationally advantageous if the number of receptors is less than the number of sources considered. The combination of an LPDM with the backward (adjoint) methodology is especially attractive for the application to point measurements, which can be handled without artificial numerical diffusion. Practical hints are provided for source-receptor calculations with different settings, both in forward and backward mode. The equivalence of forward and backward calculations is shown in simple tests for release and sampling of particles, pure wet deposition, pure convective redistribution and realistic transport over a short distance. Furthermore, an application example explaining measurements of Cs-137 in Stockholm as transport from areas contaminated heavily in the Chernobyl disaster is included

    Source-receptor matrix calculation with a Lagrangian particle dispersion model in backward mode

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    International audienceThe possibility to calculate linear-source receptor relationships for the transport of atmospheric trace substances with a Lagrangian particle dispersion model (LPDM) running in backward mode is shown and presented with many tests and examples. This mode requires only minor modifications of the forward LPDM. The derivation includes the action of sources and of any first-order processes (transformation with prescribed rates, dry and wet deposition, radioactive decay, etc.). The backward mode is computationally advantageous if the number of receptors is less than the number of sources considered. The combination of an LPDM with the backward (adjoint) methodology is especially attractive for the application to point measurements, which can be handled without artificial numerical diffusion. Practical hints are provided for source-receptor calculations with different settings, both in forward and backward mode. The equivalence of forward and backward calculations is shown in simple tests for release and sampling of particles, pure wet deposition, pure convective redistribution and realistic transport over a short distance. Furthermore, an application example explaining measurements of Cs-137 in Stockholm as transport from areas contaminated heavily in the Chernobyl disaster is included

    Admissions criteria and success in medical fields of study

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    Seit dem Sommersemester 2006 fĂŒhrt der Fachbereich Medizin der J. W. Goethe – UniversitĂ€t kontinuierlich eine Analyse ĂŒber den Zusammenhang der Oberstufen- und AbiturprĂŒfungsnoten mit den Studiumserfolgen bei den Frankfurter Medizinstudierenden durch. Den Rahmen hierfĂŒr bildet das Projekt Studierendenauswahl zur Identifizierung und Validierung geeigneter PrĂ€diktoren des Studienerfolgs zur universitĂ€ren Auswahl (60 Prozent der StudiumsplĂ€tze in den ZVS-FĂ€chern unterliegen der direkten Vergabekompetenz der Hochschulen). Wir prĂ€sentieren in dieser Kommunikation die Ergebnisse einer retrospektiven Datenerhebung bei den Studierenden im klinischen Studienabschnitt, welche Kurse zur Erlangung der Hochschulreife ausgewĂ€hlt wurden (n=700). Hintergrund fĂŒr dieses Vorgehen ist die Vermutung, dass zwischen der Kurswahl und dem Studienerfolg ein unmittelbarer Zusammenhang besteht. Die Studienleistungen wurden auf der Basis von fachbereichseigenen PrĂŒfungen (vorklinische und klinische Leistungsnachweise) durch die Ergebnisse in den Staatsexamina identifiziert. Des Weiteren sollte geklĂ€rt werden, wie viele Leistungskurskombinationen – bedingt durch die Vorgaben des deutschen Oberstufensystems – vorliegen. Erste Auswertungen geben zu erkennen, dass die Korrelation zwischen den erreichten Punkten der individuellen SchulfĂ€cher (Mathematik, Biologie, Chemie, Deutsch und Englisch) und den Ergebnissen im 1.Abschnitt der Ă€rztlichen PrĂŒfung deutlich fachabhĂ€ngig sind. Das Gleiche gilt fĂŒr die Leistungskurswahl: Die große Anzahl verschiedener Leistungskurskombinationen (bei 700 Studierenden ĂŒber 80) zeigt ausgesprochen variable Korrelationen mit den Leistungen im 1. Abschnitt der Ärztlichen PrĂŒfung. Dabei ist die Leistungskurskombination Mathematik + Englisch nach unserer gegenwĂ€rtigen Analyse der beste PrĂ€diktor fĂŒr Erfolg im Medizinstudium. Diese Ergebnisse könnten in naher Zukunft als Basis des universitĂ€ren Auswahlverfahrens fĂŒr Medizinstudierende dienen

    Technical note: The Lagrangian particle dispersion model FLEXPART version 6.2

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    International audienceThe Lagrangian particle dispersion model FLEXPART was originally (about 8 years ago) designed for calculating the long-range and mesoscale dispersion of air pollutants from point sources, such as after an accident in a nuclear power plant. In the meantime FLEXPART has evolved into a comprehensive tool for atmospheric transport modeling and analysis. Its application fields were extended from air pollution studies to other topics where atmospheric transport plays a role (e.g., exchange between the stratosphere and troposphere, or the global water cycle). It has evolved into a true community model that is now being used by at least 25 groups from 14 different countries and is seeing both operational and research applications. A user manual has been kept actual over the years and was distributed over an internet page along with the model's source code. In this note we provide a citeable technical description of FLEXPART's latest version (6.2)

    The Calibration of the WISE W1 and W2 Tully-Fisher Relation

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    In order to explore local large-scale structures and velocity fields, accurate galaxy distance measures are needed. We now extend the well-tested recipe for calibrating the correlation between galaxy rotation rates and luminosities -- capable of providing such distance measures -- to the all-sky, space-based imaging data from the Wide-field Infrared Survey Explorer (WISE) W1 (3.4ÎŒ3.4\mum) and W2 (4.6ÎŒ4.6\mum) filters. We find a linewidth to absolute magnitude correlation (known as the Tully-Fisher Relation, TFR) of MW1b,i,k,a=−20.35−9.56(log⁥Wmxi−2.5)\mathcal{M}^{b,i,k,a}_{W1} = -20.35 - 9.56 (\log W^i_{mx} - 2.5) (0.54 magnitudes rms) and MW2b,i,k,a=−19.76−9.74(log⁥Wmxi−2.5)\mathcal{M}^{b,i,k,a}_{W2} = -19.76 - 9.74 (\log W^i_{mx} - 2.5) (0.56 magnitudes rms) from 310 galaxies in 13 clusters. We update the I-band TFR using a sample 9% larger than in Tully & Courtois (2012). We derive MIb,i,k=−21.34−8.95(log⁥Wmxi−2.5)\mathcal{M}^{b,i,k}_I = -21.34 - 8.95 (\log W^i_{mx} - 2.5) (0.46 magnitudes rms). The WISE TFRs show evidence of curvature. Quadratic fits give MW1b,i,k,a=−20.48−8.36(log⁥Wmxi−2.5)+3.60(log⁥Wmxi−2.5)2\mathcal{M}^{b,i,k,a}_{W1} = -20.48 - 8.36 (\log W^i_{mx} - 2.5) + 3.60 (\log W^i_{mx} - 2.5)^2 (0.52 magnitudes rms) and MW2b,i,k,a=−19.91−8.40(log⁥Wmxi−2.5)+4.32(log⁥Wmxi−2.5)2\mathcal{M}^{b,i,k,a}_{W2} = -19.91 - 8.40 (\log W^i_{mx} - 2.5) + 4.32 (\log W^i_{mx} - 2.5)^2 (0.55 magnitudes rms). We apply an I-band -- WISE color correction to lower the scatter and derive MCW1=−20.22−9.12(log⁥Wmxi−2.5)\mathcal{M}_{C_{W1}} = -20.22 - 9.12 (\log W^i_{mx} - 2.5) and MCW2=−19.63−9.11(log⁥Wmxi−2.5)\mathcal{M}_{C_{W2}} = -19.63 - 9.11 (\log W^i_{mx} - 2.5) (both 0.46 magnitudes rms). Using our three independent TFRs (W1 curved, W2 curved and I-band), we calibrate the UNION2 supernova Type Ia sample distance scale and derive H0=74.4±1.4H_0 = 74.4 \pm 1.4(stat) ± 2.4\pm\ 2.4(sys) kms−1^{-1} Mpc−1^{-1} with 4% total error.Comment: 22 page, 21 figures, accepted to ApJ, Table 1 data at http://spartan.srl.caltech.edu/~neill/tfwisecal/table1.tx

    Growth Arrest of HPV-Positive Cells after Histone Deacetylase Inhibition Is Independent of E6/E7 Oncogene Expression

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    AbstractInhibitors of histone deacetylase (HDAC) are capable of arresting growth in cervical carcinoma cells in the G1 phase of the cell cycle. Although HPV E6/E7 mRNA steady-state levels appeared to be constant after prolonged treatment, time-course experiments revealed that viral transcription was transiently down-regulated between 7–10 h prior to cdk2 suppression. To test whether transitory suppression was a prerequisite for the biological outcome after HDAC inhibition, we took advantage of two immortalized human keratinocyte cell lines in which E6/E7 oncogene expression was controlled by different regulatory regions. After treatment with sodium butyrate (NaB) or trichostatin A (TSA), HPV16 upstream regulatory region (URR)-directed transcription was down-regulated, showing kinetics similar to those in cervical carcinoma cells. In contrast, ÎČ-actin promoter controlled E6/E7 transcription was even temporarily increased and finally declined to levels initially detected in the untreated controls. Both cell lines, however, were arrested in G1 and showed complete suppression of cdk2 activity that was preceded by a strong up-regulation of the cdk2 inhibitors p21CIP1 and p27KIP1. These results demonstrate that growth of HPV16/18-positive cells can be arrested by HDAC inhibitors despite ongoing HPV transcription and thus independently of any potential position effects uncoupling URR-directed gene expression by adjacent cellular promoters or by downstream 3â€Č-polyadenylation sites after viral integration into the host genome during multistep carcinogenesis

    FĂŒnf Jahre "Neue Frankfurter Studienordnung" : beeinflusst das Curriculum den Studienerfolg?

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    Kurzfassung eines Vortrags gehalten auf der GMA-Tagung vom 04.11.-06.11.2005 in MĂŒnster. Aufgrund wenig ĂŒberzeugender Leistungen seiner Studierenden im vorklinischen Studienabschnitt hat der Fachbereich Medizin der Goethe-UniversitĂ€t zum Wintersemester 2001/02 eine völlig neue Studienordnung eingefĂŒhrt, deren wesentliche Ziele das erfolgreiche Erlernen natur-, geistes- und sozialwissenschaftlicher Komponenten der normalen Biologie des Menschen mit optimaler Vorbereitung auf den klinischen Studienabschnitt binnen zweier Studienjahre und die KompatibilitĂ€t mit der ÄAppO und der ZÄAppO (jeweils alte und neue Version bzw. Vorentwurf) sind. Grundprinzipien des Curriculums sind: 1. Logisch aufeinander abgestimmte Themenblöcke, 2. Integration von makroskopischer und mikroskopischer Anatomie, 3. InterdisziplinĂ€ritĂ€t der Themenblöcke, 4. Immanente Wiederholung von Lehrinhalten durch enge Verzahnung von Plenar- und Kleingruppenveranstaltungen, 5. Aufteilung der StudienanfĂ€nger in gemischte Gruppen nach den Kriterien Geschlecht, Herkunft und Studienfach, 6. Erlernen des Umgangs mit Patienten schon vom ersten Semester an durch "Anatomie am Lebenden"-Kurse und durch den Kurs EinfĂŒhrung in die klinische Medizin. Wichtigste Ergebnisse: Steigerung der Referenzgruppe beim Physikum von ca. 25% auf >60%, relativ guter PrĂŒfungserfolg, hervorragende Sozialisation durch die frĂŒhe randomisierte Zuordnung in Kleingruppen und der sehr glatte Übergang in den klinischen Abschnitt des Medizin- bzw. Zahnmedizinstudiums

    Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns

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    We reconstructed the 3D Fourier intensity distribution of mono-disperse prolate nano-particles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast X-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the Expansion-Maximization-Compression (EMC) framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules.Comment: 4 pages, 4 figure
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