0000000000267108
AUTHOR
S. Hartmann
showing 16 related works from this author
Bronze Sculptures and Lead Objects Tell Stories About Their Creators: Investigation of Renaissance Sculptures and Ancient Ingots by Means of Neutron …
2016
Renaissance bronze objects from the Rijksmuseum (Amsterdam) col- lection and lead ingots from ancient roman shipwrecks found near Sicily (Italy) were studied by means of neutron tomography. This was done with the aim to visualize and to measure the inner structures of the objects. In this way information about the manufacturing processes in the 16th century and the conservation status from the inside of the bronze sculptures was gained. Inscriptions found under the corrosion layer of the lead ingots gave hints about the trade routes in the past. Neutron imaging was proven perfect to transmit the relatively thick layers of Pb and Cu alloys while ceramic remains, soldering connections and cor…
Search for signatures of magnetically-induced alignment in the arrival directions measured by the Pierre Auger Observatory
2011
We present the results of an analysis of data recorded at the Pierre Auger Observatory in which we search for groups of directionally-aligned events (or ‘multiplets’) which exhibit a correlation between arrival direc- tion and the inverse of the energy. These signatures are expected from sets of events coming from the same source after having been deflected by intervening coherent magnetic fields. The observation of several events from the same source would open the possibility to accurately reconstruct the position of the source and also measure the integral of the component of the magnetic field orthogonal to the trajectory of the cos- mic rays. We describe the largest multiplets found an…
The Fluorescence Detector of the Pierre Auger Observatory
2010
The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detecto…
Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory
2011
We present the results of searches for dipolar-type anisotropies in different energy ranges above 2.5 × 1017 eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% C.L. for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.
Muons in air showers at the Pierre Auger Observatory
2015
We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62° and 80°. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 1019eV shower with a zenith angle of 67°, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68±0.04±0.48(sys))×107 muons with energies large…
Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory
2015
Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with E ≥ 6×1019 eV by analyzing cosmic rays with energies above E ≥ 5×1018 eV arriving within an angular separation of approximately 15∘. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with …
Searches for anisotropies in the arrival directions of the highest energy cosmic rays detected by the Pierre Auger Observatory
2015
We analyze the distribution of arrival directions of ultra-high energy cosmic rays recorded at the Pierre Auger Observatory in 10 years of operation. The data set, about three times larger than that used in earlier studies, includes arrival directions with zenith angles up to $80^\circ$, thus covering from $-90^\circ$ to $+45^\circ$ in declination. After updating the fraction of events correlating with the active galactic nuclei (AGNs) in the V��ron-Cetty and V��ron catalog, we subject the arrival directions of the data with energies in excess of 40 EeV to different tests for anisotropy. We search for localized excess fluxes and for self-clustering of event directions at angular scales up t…
Measurement of the radiation energy in the radio signal of extensive air showers as a universal estimator of cosmic-ray energy
2016
We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the d…
Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory
2011
Erratum: Phys. Rev. D 85, 029902(E) (2012) [http://dx.doi.org/10.1103/PhysRevD.85.029902]
The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory
2011
We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than $60^\circ$, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ~2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution t…
Sorafenib in combination with docetaxel as first-line therapy for HER2-negative metastatic breast cancer: Final results of the randomized, double-bli…
2019
Abstract Background This multicenter, double-blind phase II study assessed the antitumor activity and toxicity profile of docetaxel with the antiangiogenic multikinase inhibitor sorafenib or matching placebo as a first-line treatment in patients with metastatic or locally advanced HER2-negative breast cancer. Patients and methods Patients were randomized 1:1 to receive docetaxel 100 mg/m2 on day 1 every 3 weeks in combination with sorafenib 400 mg bid or placebo on days 2–18 of each cycle until tumor progression, or unacceptable toxicity. Sorafenib/placebo could be continued at the investigator's discretion if docetaxel was stopped due to toxicity. Primary endpoint was progression free surv…
Surface modification of mineral dust particles by sulphuric acid processing: implications for CCN and IN abilities
2011
Abstract. The ability of coated mineral dust particles to act as cloud condensation nuclei (CCN) and ice nuclei (IN) was investigated at LACIS (Leipzig Aerosol Cloud Interaction Simulator) during the FROST1- and FROST2-campaigns (Freezing of dust). Sulphuric acid was condensed on the particles which afterwards were optionally humidified, treated with ammonia vapour and/or heat. By means of aerosol mass spectrometry we found evidence that processing of mineral dust particles with sulphuric acid leads to surface modifications of the particles. These surface modifications are responsible for the observed reduction of the IN activation of the particles. The observed particle mass spectra sugges…
Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers
2016
To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS) for the synchronization of individual detector station clocks. Unfortunately, GPS timing is expected to have an accuracy no better than about 5 ns. In practice, in particular in AERA, the GPS clocks exhibit drifts on the order of tens of ns. We developed a technique to correct for the GPS drifts, and an independent method is used to cross-check that indeed we reach a nanosecond-scale timing accura…
CCDC 175409: Experimental Crystal Structure Determination
2003
Related Article: R.F.Winter, S.Hartmann, S.Zalis, K.W.Klinkhammer|2003|Dalton Trans.||2342|doi:10.1039/b211774f
CCDC 154230: Experimental Crystal Structure Determination
2003
Related Article: R.-C.Harbort, S.Hartmann, R.F.Winter, K.W.Klinkhammer|2003|Organometallics|22|3171|doi:10.1021/om030317i
FAVARA FUTURES. Research workshop, Start conference. Dynamics of periphery
2017
The book collects a result of the project between the University of Palermo and Leibniz Universität Hannover, “Dynamics of Periphery” funded in the University Dialogue Programme Southern Europe of DAAD. The conceptual approaches collected in the book are combined with a project report of a workshop in Favara with master students of both universities; in collaboration with the municipality of Favara and with FARM Cultural Park Favara. The trans-versal research between architecture, urban design, arts, local and regional development highlights the need and the potential of new ways to integrate “Dynamics of Periphery” in debates and policies about futures of habitat in Europe.