Ground-satellite coordinated study of the April 5, 1979 events: observation of 0+ cyclotron waves

In a period of particularly large magnetospheric disturbance, large amplitude pc2 waves were observed in the late dawn sector on GEOS-2 and in the vicinity of the foot-point of the satellite's field line. The waves have dominantly left-hand polarization and their frequency is closely correlated to the O+ gyrofrequency in the magnetosphere. After the start of the pc2 activity, the GEOS-2 particle detectors measured an enhanced flux of energetic O+ ions in the energy range from 0.9-16 keV. By calculating the dispersion of ion cyclotron waves in a multicomponent plasma, it is shown that the energetic O+ ions can destabilize the observed pc2 waves.           ARK: https://n2t.net/ark:/88439/y043392 Permalink: https://geophysicsjournal.com/article/110 &nbsp

A RAS-independent biomarker panel to reliably predict response to MEK inhibition in colorectal cancer

BACKGROUND: In colorectal cancer (CRC), mutations of genes associated with the TGF-β/BMP signaling pathway, particularly affecting SMAD4, are known to correlate with decreased overall survival and it is assumed that this signaling axis plays a key role in chemoresistance. METHODS: Using CRISPR technology on syngeneic patient-derived organoids (PDOs), we investigated the role of a loss-of-function of SMAD4 in sensitivity to MEK-inhibitors. CRISPR-engineered SMAD4(R361H) PDOs were subjected to drug screening, RNA-Sequencing, and multiplex protein profiling (DigiWest(R)). Initial observations were validated on an additional set of 62 PDOs with known mutational status. RESULTS: We show that loss-of-function of SMAD4 renders PDOs sensitive to MEK-inhibitors. Multiomics analyses indicate that disruption of the BMP branch within the TGF-β/BMP pathway is the pivotal mechanism of increased drug sensitivity. Further investigation led to the identification of the SFAB-signature (SMAD4, FBXW7, ARID1A, or BMPR2), coherently predicting sensitivity towards MEK-inhibitors, independent of both RAS and BRAF status. CONCLUSION: We identified a novel mutational signature that reliably predicts sensitivity towards MEK-inhibitors, regardless of the RAS and BRAF status. This finding poses a significant step towards better-tailored cancer therapies guided by the use of molecular biomarkers

Wiechert’sche Erdbebenwarte in Göttingen weiterhin aktiv

Die 1902 von Emil Wiechert errichtete Göttinger Erdbebenstation GTT ist heute noch voll funktionsfähig und wird seit 2005 vom Verein Wiechert'sche Erdbebenwarte Göttingen betreut und von vielen Besuchern bestaunt. Die Registrierung einer 3 km entfernten Bombensprengung zeigt eindrucksvoll die große Übereinstimmung der Seismogramme des 17t-Pendels von GTT und dem benachbarten STS-2-Breitbandseismometer der Station GTTG.DFG, SUB Göttingenresearc

Wiechert’sche Erdbebenwarte Göttingen - Auswertung seismischer Daten als Thema einer Facharbeit

Während der Corona-Pandemie schrieb der Schüler Pascal Schmitt mit Unterstützung des Vereins Wiechert'sche Erdbebenwarte Göttingen e.V.  im "Homeschooling" eine Facharbeit über die Auswertung seismischer Daten. Darin werden einige Daten eines Nah- und eines Fernbebens analysiert, die in Göttingen an der modernen Station GTTG (STS-2-Seismometer) und der historischen Station GTT (Wiechert-Seismographen) registriert wurden - nah und fern, neu und alt werden miteinander verglichen.DFG, SUB Göttingenresearc

Ground observations of geomagnetic pulsations during a quiet magnetospheric interval correlated with satellite plasma measurements

Analytical results for five different geomagnetic pulsation events which occurred between 0 and 10 UT on November 28, 1977 are presented. The periods and latitudinal characteristics of the pulsations recorded on three chains of magnetometers in northern Europe are compared with theoretical eigenperiods calculated from simultaneous plasma density and composition measurements made in the plasmatrough and at the plasmapause by the relaxation sounder experiment and the Ion Composition Experiment on GEOS-1. The plasmapause was detected twice, by both measurement and experiment. Plasma density measurements were used to calculate the variation of the natural eigenperiods of different wave modes with latitude in the plasmatrough and at the plasmapause. The characteristics of the continuous pulsations generally corroborate the calculated eigenperiods. The Pi2 event provides evidence of a surface wave on the plasmapause with a period in close agreement with the calculated eigenperiod

From San Francisco to Tōhoku – 111 yr of continuous earthquake recording in Göttingen

In 1902, the so-called Erdbebenhaus (earthquake house) was built in the garden of the Institute of Geophysics of the University of Göttingen to host and protect the very sensitive and fragile seismographs designed by Emil Wiechert. These instruments were the standard at their time, and they are still in operation today, documenting 111 yr of almost continuous seismological observations. Since 2005, the observatory is owned by the Wiechert'sche Erdbebenwarte Göttingen e.V. (Wiechert's earthquake observatory in Göttingen, registered society). This society aims at extending the observational record and protecting the observatory as a cultural heritage. In this paper we review the history of the observatory in the last 111 yr. Special attention is given to the developments in the last decade, when the observatory and further historic buildings and instruments changed ownership. Due to the efforts by the society, the observatory is still running now and open to the public. In addition, it is a part of the German Regional Seismic Network and, thus, observations can be used for scientific investigations

Pc5 pulsations and their possible source mechanisms: a case study

During the interval 0400-1600 UT on August 31, 1978 strong pc5 activity was observed in the morning and afternoon sector of the magnetosphere. Using data from a world-wide network of ground-magnetometer stations and from the geostationary satellites GEOS 2, GOES 2 and 3 as well as the satellite pair ISEE 1 and 2 a case study was performed with special respect to the question of possible source mechanisms responsible for the observed pulsations. Like earlier workers we came up with the result that the Kelvin-Helmholtz instability at the magnetopause or in the low latitude boundary layer is a likely candidate. In particular we found a change in the azimuthal phase propagation direction from westwards on the morning side and eastward on the afternoon side. Also the sense of polarization and the azimuth of the ground magnetic disturbance in the horizontal plane changed across the meridian of the stagnation point as predicted by a Kelvin-Helmholtz instability source mechanism. A more detailed analysis was carried out for an isolated, large amplitude pc5 event at 1040 UT. At the same time magnetic field observations from the ISEE satellite pair indicate a flux transfer event (FTE) like disturbance at the magnetopause. Also indications of magnetopause boundary oscillations were found, and we feel that this FTE-like event constitutes a possible source for the observed impulsive pc5 event recorded on the ground and on GEOS 2. Furthermore, as the observed pc5 pulsations exhibit a wave-packet structure, we studied whether these wave packets coincided with substorms or substorm intensifications observed simultaneously in the nighttime magnetosphere. However, only a partial one-to-one correlation was found.           ARK: https://n2t.net/ark:/88439/y054611 Permalink: https://geophysicsjournal.com/article/205 &nbsp