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Search Results: 1 - 10 of 431 matches for " Lothar Oberauer "
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The HLMA project: determination of high delta-m^2 LMA mixing parameters and constraint on |U_e3| with a new reactor neutrino experiment
Stefan Schoenert,Thierry Lasserre,Lothar Oberauer
Physics , 2002, DOI: 10.1016/S0927-6505(02)00181-0
Abstract: In the forthcoming months, the KamLAND experiment will probe the parameter space of the solar large mixing angle (LMA) MSW solution as the origin of the solar neutrino deficit with $\nuebar$'s from distant nuclear reactors. If however the solution realized in nature is such that $\Dm2_{sol} \gsim 2 \cdot 10^{-4}$ eV$^2$ (thereafter named the HLMA region), KamLAND will only observe a rate suppression but no spectral distortion and hence it will not have the optimal sensitivity to measure the mixing parameters. In this case, we propose a new medium baseline reactor experiment located at Heilbronn (Germany) to pin down the precise value of the solar mixing parameters. In this paper, we present the Heilbronn detector site, we calculate the $\nuebar$ interaction rate and the positron spectrum expected from the surrounding nuclear power plants. We also discuss the sensitivity of such an experiment to |U_e3| in both normal and inverted neutrino mass hierarchy scenarios. We then outline the detector design, estimate background signals induced by natural radioactivity as well as by in-situ cosmic ray muon interaction, and discuss a strategy to detect the anti-neutrino signal 'free of background'.
Nuclear physics for geo-neutrino studies
Gianni Fiorentini,Aldo Ianni,George Korga,Marcello Lissia,Fabio Mantovani,Lino Miramonti,Lothar Oberauer,Michel Obolensky,Oleg Smirnov,Yury Suvorov
Physics , 2009, DOI: 10.1103/PhysRevC.81.034602
Abstract: Geo-neutrino studies are based on theoretical estimates of geo-neutrino spectra. We propose a method for a direct measurement of the energy distribution of antineutrinos from decays of long-lived radioactive isotopes. We present preliminary results for the geo-neutrinos from Bi-214 decay, a process which accounts for about one half of the total geo-neutrino signal. The feeding probability of the lowest state of Bi-214 - the most important for geo-neutrino signal - is found to be p_0 = 0.177 \pm 0.004 (stat) ^{+0.003}_{-0.001} (sys), under the hypothesis of Universal Neutrino Spectrum Shape (UNSS). This value is consistent with the (indirect) estimate of the Table of Isotopes (ToI). We show that achievable larger statistics and reduction of systematics should allow to test possible distortions of the neutrino spectrum from that predicted using the UNSS hypothesis. Implications on the geo-neutrino signal are discussed.
Detecting the Diffuse Supernova Neutrino Background with LENA
Randolph M?llenberg,Franz von Feilitzsch,Dominikus Hellgartner,Lothar Oberauer,Marc Tippmann,Jürgen Winter,Michael Wurm,Vincenz Zimmer
Physics , 2014, DOI: 10.1103/PhysRevD.91.032005
Abstract: LENA (Low Energy Neutrino Astronomy) has been proposed as a next generation 50 kt liquid scintillator detector. Its large target mass allows to search for the Diffuse Supernova Neutrino Background (DSNB), which was generated by the cumulative emissions of all core-collapse supernovae throughout the universe. Indistinguishable background from reactor and atmospheric electron antineutrinos limits the detection window to the energy range between 9.5 MeV and 25 MeV. Depending on the mean supernova neutrino energy, about 5 to 10 events per year are expected in this energy window. The background from neutral current reactions of atmospheric neutrinos surpasses the DSNB by more than one order magnitude, but can be suppressed by pulse shape discrimination. Assuming that the residual background is known with 5% uncertainty, the DSNB can be detected with 2 sigma significance after 10 years of data taking. In case that no hint for a signal is seen, current standard DSNB models would be ruled out with more than 90% C.L.
Detecting the Upturn of the Solar $^8$B Neutrino Spectrum with LENA
Randolph M?llenberg,Franz von Feilitzsch,Dominikus Hellgartner,Lothar Oberauer,Marc Tippmann,Jürgen Winter,Michael Wurm,Vincenz Zimmer
Physics , 2014, DOI: 10.1016/j.physletb.2014.08.053
Abstract: LENA (Low Energy Neutrino Astronomy) has been proposed as a next generation 50 kt liquid scintillator detector. The large target mass allows a high precision measurement of the solar $^8$B neutrino spectrum, with an unprecedented energy threshold of 2 MeV. Hence, it can probe the MSW-LMA prediction for the electron neutrino survival probability in the transition region between vacuum and matter-dominated neutrino oscillations. Based on Monte Carlo simulations of the solar neutrino and the corresponding background spectra, it was found that the predicted upturn of the solar $^8$B neutrino spectrum can be detected with 5 sigma significance after 5 y.
The Physics Potential of the LENA Detector
Michael Wurm,Franz von Feilitzsch,Marianne Goeger-Neff,Tobias Lachenmaier,Timo Lewke,Quirin Meindl,Randolph Moellenberg,Lothar Oberauer,Juha Peltoniemi,Walter Potzel,Marc Tippmann,Juergen Winter
Physics , 2010,
Abstract: The large-volume liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) has been proposed as a next-generation experiment for low-energy neutrinos. High-precision spectroscopy of solar, Supernova and geo-neutrinos provides a new access to the otherwise unobservable interiors of Earth, Sun and heavy stars. Due to the potent background discrimination, the detection of the Diffuse Supernova Neutrino Background is expected for the first time in LENA. The sensitivity of the proton lifetime for the decay into Kaon and antineutrino will be increased by an order of magnitude over existing experimental limits. Recent studies indicate that liquid-scintillator detectors are capable to reconstruct neutrino events even at GeV energies, providing the opportunity to use LENA as far detector in a long-baseline neutrino beam experiment.
Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors
Michael Wurm,Franz von Feilitzsch,Marianne Goeger-Neff,Martin Hofmann,Tobias Lachenmaier,Timo Lewke,Teresa Marrodan Undagoitita,Quirin Meindl,Randoplh Moellenberg,Lothar Oberauer,Walter Potzel,Marc Tippmann,Sebastian Todor,Christoph Traunsteiner,Juergen Winter
Physics , 2010, DOI: 10.1063/1.3397322
Abstract: For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents PXE, LAB, and Dodecane which are under discussion for next-generation experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range from 415 to 440nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
Mouse models for breast cancer
Lothar Hennighausen
Breast Cancer Research , 1999, DOI: 10.1186/bcr20
Abstract: Experiments conducted by Philip Leder and coworkers 15 years ago represent a milestone in breast cancer research [2]. They fused the long terminal repeat (LTR) of the mouse mammary tumor virus (MMTV) to the human c-myc proto-oncogene and incorporated this hybrid gene into mice. These transgenic mice expressed the human myc protein in their mammary glands, which resulted in the development of breast tumors [2]. This landmark paper helped to establish an entirely new research arena poised to identify genetic pathways that control breast cancer. After decades of research on tissue culture cells, both federal and private funding agencies saw the opportunity to extend investigations into settings that more closely resembled the human condition. Fifteen years after the study by Leder and coworkers, research by Deng (a former student of Leder) and coworkers set another milestone towards this goal. These investigators succeeded in inactivating the breast cancer gene Brca1 specifically in mammary epithelial cells of mice, and they demonstrated that mammary tumors coincided with genome instability [3]. The distinct lesson learned from these studies was that the wrongful expression of an oncogene and the inactivation of a tumor suppressor gene in mice can cause cancer, just like in humans. However, the myc and Brca1 mice differ in two fundamental aspects from the human situation. In the myc mice oncogene activity occurs as early as puberty, whereas in humans genetic changes leading to cancer may occur later in life. The appearance of tumors in Brca1 conditional mice depends on the loss of both alleles, whereas in humans only one BRCA1 allele is altered (for discussion, see [4]).Understanding genetic pathways was considered to be, and still remains the prerequisite for the development of molecular and pharmacological agents to treat and prevent cancer. Over the past 15 years almost 100 mouse models have been generated that permit the investigation of defined aspects of tumorige
Inhibition of homologous recombination repair with Pentoxifylline targets G2 cells generated by radiotherapy and induces major enhancements of the toxicity of cisplatin and melphalan given after irradiation
Lothar Bohm
Radiation Oncology , 2006, DOI: 10.1186/1748-717x-1-12
Abstract: The methylxanthine drug Pentoxifylline (TRENTAL, Sanofi-Aventis) is clinically well established for the treatment of cerebral ischemia and a variety of other vasoocclusive disorders such as intermittent claudication. [14,50]. Systemically the drug operates by enhancing the flexibility of blood cell membranes and reducing blood viscosity. The positive influence of Pentoxifylline on the microcirculation and peripheral oxygenation has led to applications in experimental radiotherapy showing small but consistent improvements of the radiotoxicity. Injection of PFX followed by irradiation 45 minutes later produces a 1.1–1.5 fold enhancement of tumour growth delay and this is associated with a marked reduction of tumour anoxia.[10,23,25-27,41,42,47,52].Apart from the systemic effects there is now a long list of published data indicating that Pentoxifylline (and the related drug caffeine) influences the radiobiological responses of tumour cells in an oxygen independent manner. Given to tumour cell cultures before irradiation at the subtoxic dose of 2 mM, Pentoxifylline effectively enhances radiotoxicity measured by clonogenic cell survival by factors of 1.2–2.0 [3,4,9,45-47].In the following I summarize our own [54] and other new in vitro data which explore the effects of this interesting drug on the damage responses of tumour cells. It is shown that Pentoxifylline emerges as an effective repair inhibitor and that this new mechanistic understanding shows great promise for application in tumour therapy.The determination of the drug toxicity enhancement factors for Melphalan, Daunorubicin and Cisplatin are based on chemosensitivity measurements using the crystal violet assay. G2/M block abrogation and measurment of cell survival under conditions of G2 block abrogation and drug addition involved control experiments measuring cell survival for irradiation alone, Pentoxifylline alone, Pentoxifylline plus irradiation, Pentoxifylline plus drug at 5 % toxicity and cytostatic drug a
E-Books – den Wandel professionell gestalten / E-books – managing the change professionally
Nunnenmacher, Lothar
GMS Medizin-Bibliothek-Information , 2010,
Abstract: Even acknowledging the considerable reservations of some users – we have to recognize the overall trend towards the use of e-books. The situation resembles the transition from print to electronic journals about ten years ago. Two trends are converging here: On the one hand, there is a strongly growing offer of scientific monographic literature in electronic format, and on the other hand, there has been significant progress in the technological possibilities for the reception of e-books, in particular regarding display technologies. The transition from print to electronic books provides a multiplicity of new challenges to the libraries, not least because of the overwhelming quantity of current and potential titles. For example, the ETH-Bibliothek has doubled the number of e-books in the catalogue in each year in the past few years. In 2008, for the first time more electronic than print monographs were purchased and catalogued. For the selection of e-books, the ETH-Bibliothek has defined extensive criteria. To include the individual titles of larger e-book packages into the catalogue, metadata were imported in a complex semi-automated procedure. There is only one catalogue record for printed and digital forms of the same title, so that users can immediately see, whether they can borrow the book in print form or access it directly online. A key feature for optimal benefits within the cataloguing network is the linking via a link resolver. For a stable compilation of the usage of electronic resources, the calculation of yearly usage on the basis of the median is described. Of course, many developments concerning the relatively new media type e-book are under way, and many questions are therefore still open. They range from acquisition models and the selection and processing of titles to possible restrictions on the use and the integration of freely available sources to the use of e-books in interlibrary loan and archiving.
Von der Bibliothek zum Lernzentrum - Ver nderungen in der Medizinischen Bibliothek der Charité
Nunnenmacher, Lothar
GMS Medizin-Bibliothek-Information , 2005,
Abstract: Nowadays it has become quite natural for the doctors and scientists of the Charité to use the services of the Medical Library at their desktops. Therefore the library as a physical location can be adopted to better suit the needs of the students. This means, first of all, more space for the textbook and reference collections as well as more seats for reading and learning. However, learning media will also develop towards digital forms in the coming years. Beyond the supply of media the challenge for the library will therefore increasingly consist in offering environments and services for the different forms of learning.
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