278 research outputs found
Geomagnetic disturbances at high latitudes during very low solar wind density event
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94969/1/grl13480.pd
Photometric AGN reverberation mapping - an efficient tool for BLR sizes, black hole masses and host-subtracted AGN luminosities
Photometric reverberation mapping employs a wide bandpass to measure the AGN
continuum variations and a suitable band, usually a narrow band (NB), to trace
the echo of an emission line in the broad line region (BLR). The narrow band
catches both the emission line and the underlying continuum, and one needs to
extract the pure emission line light curve. We performed a test on two local
AGNs, PG0003+199 (=Mrk335) and Ark120, observing well-sampled broad- (B, V) and
narrow-band light curves with the robotic 15cm telescope VYSOS-6 on Cerro
Armazones, Chile. In PG0003+199, H_alpha dominates the flux in the NB by 85%,
allowing us to measure the time lag of H_alpha against B without the need to
correct for the continuum contribution. In Ark120, H_beta contributes only 50%
to the flux in the NB. The cross correlation of the B and NB light curves shows
two distinct peaks of similar strength, one at lag zero from the autocorrelated
continuum and one from the emission line at tau_cent = 47.5 +/- 3.4 days. We
constructed a synthetic H_beta light curve, by subtracting a scaled V light
curve, which traces the continuum, from the NB light curve. The cross
correlation of this synthetic H_beta light curve with the B light curve shows
only one major peak at tau_cent = 48.0 +/- 3.3 days, while the peak from the
autocorrelated continuum at lag zero is absent. We conclude that, as long as
the emission line contributes at least 50% to the bandpass, the pure emission
line light curve can be reconstructed from photometric monitoring data so that
the time lag can be measured. For both objects the lags we find are consistent
with spectroscopic reverberation results. While the dense sampling (median 2
days) enables us to determine tau_cent with small (10%) formal errors, we
caution that gaps in the light curves may lead to much larger systematic
uncertainties. (Abstract shortened, see the manuscript.)Comment: 12 pages, 15 figures, accepted for publication in Astronomy and
Astrophysic
Coordinated observation of field line resonance in the mid-tail
Standing Alfv&#233;n waves of 1.1 mHz (~15 min in period) were observed by the Cluster satellites in the mid-tail during 06:00-07:00&nbsp;UT on 8&nbsp;August 2003. Pulsations with the same frequency were also observed at several ground stations near Cluster's footpoint. The standing wave properties were determined from the electric and magnetic field measurements of Cluster. Data from the ground magnetometers indicated a latitudinal amplitude and phase structure consistent with the driven field line resonance (FLR) at 1.1 mHz. Simultaneously, quasi-periodic oscillations at different frequencies were observed in the post-midnight/early morning sector by GOES&nbsp;12 (<i>l</i><sub>0</sub>&asymp;8.7), Polar (<i>l</i><sub>0</sub>&asymp;11-14) and Geotail (<i>l</i><sub>0</sub>&asymp;9.8). The 8&nbsp;August 2003 event yields rare and interesting datasets. It provides, for the first time, coordinated in situ and ground-based observations of a very low frequency FLR in the mid-tail on stretched field lines
Improved diagnostics targeting c-MET in non-small cell lung cancer: expression, amplification and activation?
Background: Several c-MET targeting inhibitory molecules have already shown promising results in the treatment of patients with Non-small Cell Lung Cancer (NSCLC). Combination of EGFR-and c-MET-specific molecules may overcome EGFR tyrosine kinase inhibitor (TKI) resistance. The aim of this study was to allow for the identification of patients who might benefit from TKI treatments targeting MET and to narrow in on the diagnostic assessment of MET. Methods: 222 tumor tissues of patients with NSCLC were analyzed concerning c-MET expression and activation in terms of phosphorylation (Y1234/1235 and Y1349) using a microarray format employing immunohistochemistry (IHC). Furthermore, protein expression and MET activation was correlated with the amplification status by Fluorescence in Situ Hybridization (FISH). Results: Correlation was observed between phosphorylation of c-MET at Y1234/1235 and Y1349 (spearman correlation coefficient r(s) = 0.41;p 0.05). c-MET gene amplification was detected in eight of 214 patients (3.7 %). No significant association was observed between c-MET amplification, c-MET protein expression and phosphorylation. Conclusion: Our data indicate, that neither expression of c-MET nor the gene amplification status might be the best way to select patients for MET targeting therapies, since no correlation with the activation status of MET was observed. We propose to take into account analyzing the phosphorylation status of MET by IHC to select patients for MET targeting therapies. Signaling of the receptor and the activation of downstream molecules might be more crucial for the benefit of therapeutics targeting MET receptor tyrosine kinases than expression levels alone
Performance of Different Diagnostic PD-L1 Clones in Head and Neck Squamous Cell Carcinoma
Background: The approval of immune checkpoint inhibitors in combination with specific diagnostic biomarkers presents new challenges to pathologists as tumor tissue needs to be tested for expression of programmed death-ligand 1 (PD-L1) for a variety of indications. As there is currently no requirement to use companion diagnostic assays for PD-L1 testing in Germany different clones are used in daily routine. While the correlation of staining results has been tested in various entities, there is no data for head and neck squamous cell carcinomas (HNSCC) so far.
Methods: We tested five different PD-L1 clones (SP263, SP142, E1L3N, 22-8, 22C3) on primary HNSCC tumor tissue of 75 patients in the form of tissue microarrays. Stainings of both immune and tumor cells were then assessed and quantified by pathologists to simulate real-world routine diagnostics. The results were analyzed descriptively and the resulting staining pattern across patients was further investigated by principal component analysis and non-negative matrix factorization clustering.
Results: Percentages of positive immune and tumor cells varied greatly. Both the resulting combined positive score as well as the eligibility for certain checkpoint inhibitor regimens was therefore strongly dependent on the choice of the antibody. No relevant co-clustering and low similarity of relative staining patterns across patients was found for the different antibodies.
Conclusions: Performance of different diagnostic anti PD-L1 antibody clones in HNSCC is less robust and interchangeable compared to reported data from other tumor entities. Determination of PD-L1 expression is critical for therapeutic decision making and may be aided by back-to-back testing of different PD-L1 clones
The significance of trust in the political system and motivation for pupils' learning progress in politics lessons
Very little research has been conducted on the contribution of political education to learning progress in Germany. Hence, there is a need for intervention studies measuring performance against the theoretical background of a political competence model. This model comprises three constructs: subject knowledge, motivation and attitudes. According to this model, politics lessons should not only convey knowledge but also arouse subject interest, promote political attitudes and develop problem-solving skills. This study investigates how knowledge acquisition is influenced by intervention using theory-oriented teaching materials on the European Union, intervention using conventional textbooks on the European Union and politics lessons without any reference to the European Union. It further asks how the performance-related self-concept and subject interest in political issues impact political knowledge and whether civic virtue and trust in the system are related to it. The sample comprises 1071 pupils. Theory-oriented politics classes lead to greater growth of pupilsâ knowledge than in the control group. As anticipated, this study proves that a positive subject-specific self-concept impacts knowledge. The examination of political attitudes reveals a positive correlation between civic virtue and knowledge. There is no connection between trust in the political system and knowledge
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Ground-based and satellite observations of high-latitude auroral activity in the dusk sector of the auroral oval
On 7 December 2000, during 13:30-15:30 UT the MIRACLE all-sky camera at Ny Alesund observed auroras at high-latitudes (MLAT similar to 76) simultaneously when the Cluster spacecraft were skimming the magnetopause in the same MLT sector (at similar to 16:00-18:00 MLT). The location of the auroras (near the ionospheric convection reversal boundary) and the clear correlation between their dynamics and IMF variations suggests their close relationship with R1 currents. Consequently, we can assume that the Cluster spacecraft were making observations in the magnetospheric region associated with the auroras, although exact magnetic conjugacy between the ground-based and satellite observations did not exist. The solar wind variations appeared to control both the behaviour of the auroras and the magnetopause dynamics. Auroral structures were observed at Ny Alesund especially during periods of negative IMF B-Z. In addition, the Cluster spacecraft experienced periodic (T similar to 4 - 6 min) encounters between magnetospheric and magnetosheath plasmas. These undulations of the boundary can be interpreted as a consequence of tailward propagating magnetopause surface waves. Simultaneous dusk sector ground-based observations show weak, but discernible magnetic pulsations (Pc 5) and occasionally periodic variations (T - 2 - 3 min) in the high-latitude auroras. In the dusk sector, Pc 5 activity was stronger and had characteristics that were consistent with a field line resonance type of activity. When IMF BZ stayed positive for a longer period, the auroras were dimmer and the spacecraft stayed at the outer edge of the magnetopause where they observed electromagnetic pulsations with T similar to 1 min. We find these observations interesting especially from the viewpoint of previously presented studies relating poleward-moving high-latitude auroras with pulsation activity and MHD waves propagating at the magnetospheric boundary layers
The development of study-specific self-efficacy during grammar school.(Zur Entwicklung der studienspezifischen Selbstwirksamkeit in der Oberstufe)
Article is in German.
Even if more and more German adolescents acquire a university entrance qualification, not all of them finally enrol at a university. In particular, the transition from school to university strongly depends on parentâs education. Even with the same marks in school, adolescents from non-academic households are less likely to enrol in universities than adolescents from academic housholds. One important reason is their lower belief to master a university study. This study analyses a specific intervention in grammar school to improve study-specific self- efficacy, the belief in oneâs capabilities to master a university study, using a longitudinal design. We apply a difference-in-difference framework and show that programme participation significantly improves the study-specific self-efficacy for puplis from non- academic families but not for those from academic families. Hence, such a programme could reduce social disparities between both groups
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