The galactic antiproton spectrum at high energies: background expectation vs. exotic contributions

A new generation of upcoming space-based experiments will soon start to probe the spectrum of cosmic ray antiparticles with an unprecedented accuracy and, in particular, will open up a window to energies much higher than those accessible so far. It is thus timely to carefully investigate the expected antiparticle fluxes at high energies. Here, we perform such an analysis for the case of antiprotons. We consider both standard sources as the collision of other cosmic rays with interstellar matter, as well as exotic contributions from dark matter annihilations in the galactic halo. Up to energies well above 100 GeV, we find that the background flux in antiprotons is almost uniquely determined by the existing low-energy data on various cosmic ray species; for even higher energies, however, the uncertainties in the parameters of the underlying propagation model eventually become significant. We also show that if the dark matter is composed of particles with masses at the TeV scale, which is naturally expected in extra-dimensional models as well as in certain parameter regions of supersymmetric models, the annihilation flux can become comparable to - or even dominate - the antiproton background at the high energies considered here.Comment: 17 pages revtex4, 7 figures; minor changes (to match the published version

Quantification of Cell Subpopulations, Fractions of Dead Cells and Debris in Cell Suspensions by Laser Diffractometry

Laser diffractometry was employed for size analysis in liver cell and blood cell suspensions to assess its suitability for characterizing cell populations. The method proved sensitive to detect subpopulations in liver cells (bimodal or trimodal distributions) and to quantify their volume fractions. Cell debris and aggregates of cells could also be quantified, dead cell populations recognized by their shift in the mean cell diameter. Laser diffractometry is therefore suitable for determining the quality of cell isolations (e.g. by liver perfusion) or for following alterations in cell populations during culture of cells in suspension. Analysis of human blood allowed differenciations to be made between thrombocytes and other blood cells. No peak separation was obtained for the populations of erythrocytes and granulocytes due to their similarity in size. Monocytes could not be detected due to their extremely low number in the blood indicating the limit of the metho

Adjustment of the basin-scale circulation at 26 degrees N to variations in Gulf Stream, deep western boundary current and Ekman transports as observed by the Rapid array

The Rapid instrument array across the Atlantic Ocean along 26 degrees N provides unprecedented monitoring of the basin-scale circulation. A unique feature of the Rapid array is the combination of full-depth moorings with instruments measuring temperature, salinity, pressure time series at many depths with co-located bottom pressure measurements so that dynamic pressure can be measured from surface to bottom. Bottom pressure measurements show a zonally uniform rise (and fall) of bottom pressure of 0.015 dbar on a 5 to 10 day time scale, suggesting that the Atlantic basin is filling and draining on a short time scale. After removing the zonally uniform bottom pressure fluctuations, bottom pressure variations at 4000 m depth against the western boundary compensate instantaneously for baroclinic fluctuations in the strength and structure of the deep western boundary current so there is no basin-scale mass imbalance resulting from variations in the deep western boundary current. After removing the mass compensating bottom pressure, residual bottom pressure fluctuations at the western boundary just east of the Bahamas balance variations in Gulf Stream transport. Again the compensation appears to be especially confined close to the western boundary. Thus, fluctuations in either Gulf Stream or deep western boundary current transports are compensated in a depth independent (barotropic) manner very close to the continental slope off the Bahamas. In contrast, compensation for variations in wind-driven surface Ekman transport appears to involve fluctuations in both western basin and eastern basin bottom pressures, though the bottom pressure difference fluctuations appear to be a factor of 3 too large, perhaps due to an inability to resolve small bottom pressure fluctuations after removal of larger zonal average, baroclinic, and Gulf Stream pressure components. For 4 tall moorings where time series dynamic height (geostrophic pressure) profiles can be estimated from sea surface to ocean bottom and bottom pressure can be added, there is no general correlation between surface dynamic height and bottom pressure. Dynamic height on each mooring is strongly correlated with sea surface height from satellite observations and the variability in both dynamic height and satellite sea surface height decrease sharply as the western boundary is approached

Substrate effects on surface magetetism of Fe/W(110) from first principles

Surface magnetic properties of the pseudomorphic Fe(110) monolayer on a W(110) substrate are investigated from first principles as a function of the substrate thickness (up to eight layers). Analyzing the magnetocrystalline anisotropy energies, we find stable (with respect to the number of substrate layers) in-plane easy and hard axes of magnetization along the [1[overline 1]0] and [001] directions, respectively, reaching a value in good agreement with experiment for thick substrates. Additionally, the changes to the magnetic spin moments and the density of the Fe d states are analyzed with respect to the number of substrate layers as well as with respect to the direction of magnetization. With respect to the number of W(110) substrate layers beneath the Fe(110) surface, we find that the first four substrate layers have a large influence on the electronic and magnetic properties of the surface. Beyond the fourth layer, the substrate has only marginal influence on the surface properties.Comment: 8 Pages, 3 Figures, 3 Table

Genetically modified natural killer cells specifically recognizing the tumor-associated antigens ErbB2/HER2 and EpCAM

The continuously growing natural killer (NK) cell line NK-92 is highly cytotoxic against malignant cells of various origin without affecting normal human cells. Based on this selectivity, the potential of NK-92 cells for adoptive therapy is currently being investigated in phase I clinical studies. To further enhance the antitumoral activity of NK-92 cells and expand the range of tumor entities suitable for NK-92-based therapies, here by transduction with retroviral vectors we have generated genetically modified NK-92 cells expressing chimeric antigen receptors specific either for the tumor-associated ErbB2 (HER2/neu) antigen or the human Epithelial Cell Adhesion Molecule (Ep-CAM). Both antigens are overexpressed by many tumors of epithelial origin. The chimeric antigen receptors consist of either the ErbB2 specific scFv(FRP5) antibody fragment or the Ep-CAM specific scFv(MOC31), a flexible hinge region derived from CD8, and transmembrane and intracellular regions of the CD3 zeta chain. Transduced NK-92-scFv(FRP5)-zeta or NK-92-scFv(MOC31)-zeta cells express high levels of the fusion proteins on the cell surface as determined by FACS analysis. In europium release assays no difference in cytotoxic activity of NK-92 and transduced NK-92 cells towards ErbB2 or Ep-CAM negative targets was found. However, even at low effector to target ratios transduced NK-92 cells specifically and efficiently lysed established ErbB2 or Ep-CAM expressing tumor cells that were completely resistant to cytolytic activity of parental NK-92 cells. Similarly, ErbB2-positive primary breast cancer cells isolated from pleural effusions of patients with recurrent disease were selectively killed by NK-92-scFv(FRP5)-zeta. In an in vivo model in immunodeficient mice treatment with retargeted NK-92-scFv(FRP5)-zeta, but not parental NK-92 cells resulted in markedly delayed growth of ErbB2 transformed cancer cells. These results demonstrate that efficient retargeting of NK-92 cytotoxicity can be achieved, and might allow the generation of potent cell-based therapeutics for the treatment of ErbB2 and Ep-CAM expressing malignancies. This therapeutic approach might be applicable for a large variety of different cancers where suitable cell surface antigens have been identified

Structural analysis of the Arunta Block and Amadeus Basin (Central Australia) by means of digital remote sensing techniques and field data

Der proterozoische Arunta Block und das altpaläozoische Amadeus Basin zeichnen sich durch jeweils eigenständige lithologische Abfolgen und tektonische Deformationstypen aus. Der Kontaktbereich dieser intrakratonen Blöcke wirft seit Jahren Diskussionen hinsichtlich des tektonischen Baus auf: von hypothetischen weitreichenden Überschiebungsdecken (nappes) bis hin zu einfachen kleindimensionierten Störungen oder Verschleppungen (thrusts). Im Rahmen dieser Arbeit wird versucht, diese Elemente anhand von multispektralen Landsat-TM-Daten und Analysen von Luftbildern und ERS-1-Daten makroskopisch zu erfassen und zu deuten. Es ist möglich, Gesteinseinheiten und die unterschiedlichen Deformationsstile repräsentativer Untersuchungsgebiete zu differenzieren, sowie auf der Basis der topographischenKarten ein digitales Höhenmodell der Region zu erstellen, das die Zusammenhänge zwischen morphologischen Gegebenheiten vor Ort und imSatellitenbild in Bezug auf die Verbreitung von Lithologien und Störungszonen verdeutlicht. Auf diese Weise entsteht das Bild eines komplexen tektonischen Spannungsfeldes, das für jeden intrakratonen Block individuelle, zeitlich voneinander getrennt wirkende Ereignisse als Auslöser für die anzutreffenden Strukturen vorsieht.The Proterozoic Arunta Block and the younger late Palaeozoic Amadeus Basin each show significant lithological sequences and tectonic deformation styles. Since years the contact zone of these intracratonic blocks raises controversial discussions concerning its tectonic origin: from hypothetic widespread nappes to simple faults and thrusts of smaller dimension everything is taken into consideration. Within the scope of this paper it is attempted to detect their macroscopic pattern by applying multispectral and further remote sensing data analysis of aerial photographs, Landsat-TM and ERS-1data. It is possible to distinguish rock units and different deformation styles of representative areas as well as to create a digital elevation model of the region on the basis of topographic maps that elucidates the coherence of morphological features in place and in the satellite image as far as the propagation of lithologies and fault zones is concerned. It arises the picture of a complex tectonictension field, that contains individual tectonic events separated by time for each structure within the intracratonic blocks

Manifestations of hard and soft technologies in immersive spaces

Immersive spaces are innately flexible. However, for learners, some constraints and scaffolding may often be valuable. This paper looks at immersive spaces as soft and hard technologies. Soft technologies are technologies enabling creative and flexible use, while hard technologies embed processes that limit creativity but provide efficiency and freedom from error. Technologies may be softened or hardened by assembly. For instance, if your Learning Management System (LMS) has no wiki, then it may be softened by adding one from outside the system. If your wiki has no assessment management system, then it may be hardened by using a LMS. For learning, the intrinsically soft nature of immersive spaces sometimes requires scaffolded hardening. This paper provides an example of an ongoing project that realizes these soft and hard technologies in an immersive virtual space and discusses the rich potential of such spaces for technology assembly

Experimental study on consumer-technology supported authentic immersion in virtual environments for education and vocational training

Despite significant and rapid technology improvements, educators have frequently failed to make use of the new opportunities to create more authentic learning scenarios. Virtual worlds offer an attractive proposition to create 3D representations of real business environments to provide an authentic learning activity for higher education students to take part in. However, the controls and displays are still clunky and unnatural, reducing the opportunity for students to immerse themselves in the event and focus on experiential learning. To overcome this challenge we examine the role of using a headset display that allows the user to change perspective with a flick of the head, improving their ability to ‘feel’ part of the environment, and thus increase their immersion in the activities that they are engaged in through more realistic control and improved perspective in the virtual environment. A series of experiments are conducted comparing the technology to established technologies and the level of control exerted by the learner (e.g., they either ‘control’ or they ‘passively observe’ as someone else controls). These experiments provide evidence that consumer-technology can improve immersion and equip educators with an affordable instrument to present classes that learners ‘take more seriously’