69 research outputs found
Evaluation von Kompetenz- und übungsbasierten Assessment Centern in einem deutschen Unternehmen
In der hier vorliegenden empirischen Studie werden in einem deutschen Unternehmen zwei klassische Assessment Center und ein Multimodales Auswahlverfahren im Hinblick auf die Hauptgütekriterien diagnostischer Verfahren untersucht. Der gravierende Unterschied des Multimodalen Auswahlverfahrens gegenüber den beiden klassischen Assessment Cen- tern ist neben dem Methodenmix das Beurteilungsprinzip.
Die Ergebnisse der Untersuchung haben deutlich gemacht, dass in den beiden klas- sischen Assessment Centern, hingegen der zugrundeliegenden Annahme, eine übungsbe- zogene statt eine dimensionsbezogene Beurteilung durch die Beobachter erfolgte. Durch die Veränderung des Beurteilungsprinzips und weitere Überarbeitungen der Übungen im Multimodalen Auswahlverfahren konnte eine höhere Trennschärfe erzielt werden. Eine Steigerung der Interrater-Korrelation im Multimodalen Auswahlverfahren gegenüber den beiden Assessment Centern wurde nicht erreicht. Jedoch konnte die Prognose des berufli- chen Erfolgs der Kandidaten und somit die Zuverlässigkeit der Einstellungsentscheidung verbessert werden
Evaluation von Kompetenz- und übungsbasierten Assessment Centern in einem deutschen Unternehmen
In der hier vorliegenden empirischen Studie werden in einem deutschen Unternehmen zwei klassische Assessment Center und ein Multimodales Auswahlverfahren im Hinblick auf die Hauptgütekriterien diagnostischer Verfahren untersucht. Der gravierende Unterschied des Multimodalen Auswahlverfahrens gegenüber den beiden klassischen Assessment Cen- tern ist neben dem Methodenmix das Beurteilungsprinzip.
Die Ergebnisse der Untersuchung haben deutlich gemacht, dass in den beiden klas- sischen Assessment Centern, hingegen der zugrundeliegenden Annahme, eine übungsbe- zogene statt eine dimensionsbezogene Beurteilung durch die Beobachter erfolgte. Durch die Veränderung des Beurteilungsprinzips und weitere Überarbeitungen der Übungen im Multimodalen Auswahlverfahren konnte eine höhere Trennschärfe erzielt werden. Eine Steigerung der Interrater-Korrelation im Multimodalen Auswahlverfahren gegenüber den beiden Assessment Centern wurde nicht erreicht. Jedoch konnte die Prognose des berufli- chen Erfolgs der Kandidaten und somit die Zuverlässigkeit der Einstellungsentscheidung verbessert werden
Pathfinder first light: alignment, calibration, and commissioning of the LINC-NIRVANA ground-layer adaptive optics subsystem
We present descriptions of the alignment and calibration tests of the
Pathfinder, which achieved first light during our 2013 commissioning campaign
at the LBT. The full LINC-NIRVANA instrument is a Fizeau interferometric imager
with fringe tracking and 2-layer natural guide star multi-conjugate adaptive
optics (MCAO) systems on each eye of the LBT. The MCAO correction for each side
is achieved using a ground layer wavefront sensor that drives the LBT adaptive
secondary mirror and a mid-high layer wavefront sensor that drives a Xinetics
349 actuator DM conjugated to an altitude of 7.1 km. When the LINC-NIRVANA MCAO
system is commissioned, it will be one of only two such systems on an 8-meter
telescope and the only such system in the northern hemisphere. In order to
mitigate risk, we take a modular approach to commissioning by decoupling and
testing the LINC-NIRVANA subsystems individually. The Pathfinder is the
ground-layer wavefront sensor for the DX eye of the LBT. It uses 12 pyramid
wavefront sensors to optically co-add light from natural guide stars in order
to make four pupil images that sense ground layer turbulence. Pathfinder is now
the first LINC-NIRVANA subsystem to be fully integrated with the telescope and
commissioned on sky. Our 2013 commissioning campaign consisted of 7 runs at the
LBT with the tasks of assembly, integration and communication with the LBT
telescope control system, alignment to the telescope optical axis, off-sky
closed loop AO calibration, and finally closed loop on-sky AO. We present the
programmatics of this campaign, along with the novel designs of our alignment
scheme and our off-sky calibration test, which lead to the Pathfinder's first
on-sky closed loop images
Phase Noise of SAW Delay Line Magnetic Field Sensors
Surface acoustic wave (SAW) sensors for the detection of magnetic fields are currently being studied scientifically in many ways, especially since both their sensitivity as well as their detectivity could be significantly improved by the utilization of shear horizontal surface acoustic waves, i.e., Love waves, instead of Rayleigh waves. By now, low-frequency limits of detection (LOD) below 100 pT/Hz can be achieved. However, the LOD can only be further improved by gaining a deep understanding of the existing sensor-intrinsic noise sources and their impact on the sensor's overall performance. This paper reports on a comprehensive study of the inherent noise of SAW delay line magnetic field sensors. In addition to the noise, however, the sensitivity is of importance, since both quantities are equally important for the LOD. Following the necessary explanations of the electrical and magnetic sensor properties, a further focus is on the losses within the sensor, since these are closely linked to the noise. The considered parameters are in particular the ambient magnetic bias field and the input power of the sensor. Depending on the sensor's operating point, various noise mechanisms contribute to f0 white phase noise, f-1 flicker phase noise, and f-2 random walk of phase. Flicker phase noise due to magnetic hysteresis losses, i.e. random fluctuations of the magnetization, is usually dominant under typical operating conditions. Noise characteristics are related to the overall magnetic and magnetic domain behavior. Both calculations and measurements show that the LOD cannot be further improved by increasing the sensitivity. Instead, the losses occurring in the magnetic material need to be decreased
Multi-Mode Love-Wave SAW Magnetic-Field Sensors
A surface-acoustic-wave (SAW) magnetic-field sensor utilizing fundamental, first- and second-order Love-wave modes is investigated. A 4.5 μ m SiO2 guiding layer on an ST-cut quartz substrate is coated with a 200 n m (Fe90Co10)78Si12B10 magnetostrictive layer in a delay-line configuration. Love-waves are excited and detected by two interdigital transducers (IDT). The delta-E effect in the magnetostrictive layer causes a phase change with applied magnetic field. A sensitivity of 1250 ° / m T is measured for the fundamental Love mode at 263 M Hz . For the first-order Love mode a value of 45 ° / m T is obtained at 352 M Hz . This result is compared to finite-element-method (FEM) simulations using one-dimensional (1D) and two-and-a-half-dimensional (2.5 D) models. The FEM simulations confirm the large drop in sensitivity as the first-order mode is close to cut-off. For multi-mode operation, we identify as a suitable geometry a guiding layer to wavelength ratio of h GL / λ ≈ 1.5 for an IDT pitch of p = 12 μ m . For this layer configuration, the first three modes are sufficiently far away from cut-off and show good sensitivity
Thin-Film-Based SAW Magnetic Field Sensors
In this work, the first surface acoustic-wave-based magnetic field sensor using thin-film AlScN as piezoelectric material deposited on a silicon substrate is presented. The fabrication is based on standard semiconductor technology. The acoustically active area consists of an AlScN layer that can be excited with interdigital transducers, a smoothing SiO2 layer, and a magnetostrictive FeCoSiB film. The detection limit of this sensor is 2.4 nT/Hz at 10 Hz and 72 pT/Hz at 10 kHz at an input power of 20 dBm. The dynamic range was found to span from about ±1.7 mT to the corresponding limit of detection, leading to an interval of about 8 orders of magnitude. Fabrication, achieved sensitivity, and noise floor of the sensors are presented
Final integration and alignment of LINC-NIRVANA
The LBT (Large Binocular Telescope), located at about 3200m on Mount Graham (Tucson, Arizona) is an innovative project undertaken by institutions from Europe and USA. LINC-NIRVANA is an instrument which provides MCAO (Multi-Conjugate Adaptive Optics) and interferometry, combining the light from the two 8.4m telescopes coherently. This configuration offers 23m-baseline optical resolution and the sensitivity of a 12m mirror, with a 2 arc-minute diffraction limited field of view. The integration, alignment and testing of such a big instrument requires a well-organized choreography and AIV planning which has been developed in a hierarchical way. The instrument is divided in largely independent systems, and all of them consist of various subsystems. Every subsystem integration ends with a verification test and an acceptance procedure. When a certain number of systems are finished and accepted, the instrument AIV phase starts. This hierarchical approach allows testing at early stages with simple setups. The philosophy is to have internally aligned subsystems to be integrated in the instrument optical path, and extrapolate to finally align the instrument to the Gregorian bent foci of the telescope. The alignment plan was successfully executed in Heidelberg at MPIA facilities, and now the instrument is being re-integrated at the LBT over a series of 11 campaigns along the year 2016. After its commissioning, the instrument will offer MCAO sensing with the LBT telescope. The interferometric mode will be implemented in a future update of the instrument. This paper focuses on the alignment done in the clean room at the LBT facilities for the collimator, camera, and High-layer Wavefront Sensor (HWS) during March and April 2016. It also summarizes the previous work done in preparation for shipping and arrival of the instrument to the telescope. Results are presented for every step, and a final section outlines the future work to be done in next runs until its final commissioning...
A unique maternal and placental galectin signature upon SARS-CoV-2 infection suggests galectin-1 as a key alarmin at the maternal–fetal interface
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic imposed a risk of infection and disease in pregnant women and neonates. Successful pregnancy requires a fine-tuned regulation of the maternal immune system to accommodate the growing fetus and to protect the mother from infection. Galectins, a family of β-galactoside–binding proteins, modulate immune and inflammatory processes and have been recognized as critical factors in reproductive orchestration, including maternal immune adaptation in pregnancy. Pregnancy-specific glycoprotein 1 (PSG1) is a recently identified gal-1 ligand at the maternal–fetal interface, which may facilitate a successful pregnancy. Several studies suggest that galectins are involved in the immune response in SARS-CoV-2–infected patients. However, the galectins and PSG1 signature upon SARS-CoV-2 infection and vaccination during pregnancy remain unclear. In the present study, we examined the maternal circulating levels of galectins (gal-1, gal-3, gal-7, and gal-9) and PSG1 in pregnant women infected with SARS-CoV-2 before vaccination or uninfected women who were vaccinated against SARS-CoV-2 and correlated their expression with different pregnancy parameters. SARS-CoV-2 infection or vaccination during pregnancy provoked an increase in maternal gal-1 circulating levels. On the other hand, levels of PSG1 were only augmented upon SARS-CoV-2 infection. A healthy pregnancy is associated with a positive correlation between gal-1 concentrations and gal-3 or gal-9; however, no correlation was observed between these lectins during SARS-CoV-2 infection. Transcriptome analysis of the placenta showed that gal-1, gal-3, and several PSG and glycoenzymes responsible for the synthesis of gal-1-binding glycotopes (such as linkage-specific N-acetyl-glucosaminyltransferases (MGATs)) are upregulated in pregnant women infected with SARS-CoV-2. Collectively, our findings identify a dynamically regulated “galectin-specific signature” that accompanies the SARS-CoV-2 infection and vaccination in pregnancy, and they highlight a potentially significant role for gal-1 as a key pregnancy protective alarmin during virus infection
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