658 research outputs found
PUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry: Nucleosynthesis Yields
Core-collapse supernovae (CCSNe) are the extremely energetic deaths of
massive stars. They play a vital role in the synthesis and dissemination of
many heavy elements in the universe. In the past, CCSN nucleosynthesis
calculations have relied on artificial explosion methods that do not adequately
capture the physics of the innermost layers of the star. The PUSH method,
calibrated against SN1987A, utilizes the energy of heavy-flavor neutrinos
emitted by the proto-neutron star (PNS) to trigger parametrized explosions.
This makes it possible to follow the consistent evolution of the PNS and to
ensure a more accurate treatment of the electron fraction of the ejecta. Here,
we present the Iron group nucleosynthesis results for core-collapse supernovae,
exploded with PUSH, for two different progenitor series. Comparisons of the
calculated yields to observational metal-poor star data are also presented.
Nucleosynthesis yields will be calculated for all elements and over a wide
range of progenitor masses. These yields can be immensely useful for models of
galactic chemical evolution.Comment: 3 pages, 3 figures, poster presentation to appear in the proceedings
of the 14th International Symposium on Nuclei in the Cosmos (NIC-XIV), Ed. S.
Kubono, JPS (Japan Physical Society
Evaluation of Corn, Soybean and Barley Varieties for Certified Organic Production—Crawfordsville Trial, 2002
Beginning in 1998, a long-term crop rotation experiment was initiated to examine the effects of organic practices on crop yield, soil quality, and grain quality. A minimum three-year crop rotation is required for certified organic crop production (National Organic Program, 2002). Organic fields at the Southeast Research Farm follow a rotation of corn-soybean-barley/red clover. Results reported here represent the fifth year of production—the second year of the row crop (corn or soybean) following a full 3-year rotation
Explosion Dynamics of Parametrized Spherically Symmetric Core-Collapse Supernova Simulations
We report on a method, PUSH, for triggering core-collapse supernova (CCSN)
explosions of massive stars in spherical symmetry. This method provides a
framework to study many important aspects of core collapse supernovae: the
effects of the shock passage through the star, explosive supernova
nucleosynthesis and the progenitor-remnant connection. Here we give an overview
of the method, compare the results to multi-dimensional simulations and
investigate the effects of the progenitor and the equation of state on black
hole formation.Comment: Proceedings for Nuclei in the Cosmos XIV, Niigata, Japan (2016
Evaluation of Corn, Soybean and Barley Varieties for Certified Organic Production, Crawfordsville–2003
Beginning in 1998, a long-term crop rotation experiment was initiated at the Southeast Research Farm (SERF) to examine the effects of organic practices on crop yields, soil quality, and grain quality. Because a soil-building crop rotation is required for certified organic crop production, organic fields at the SERF follow a rotation of corn-soybean-barley/red clover. Results reported here represent the sixth year of production, which includes two cycles of the 3- year crop rotation
How IT Consumerization Affects the Stress Level at Work: A Public Sector Case Study
IT consumerization refers to the adoption of consumer technologies in an enterprise context and is becoming increasingly important in both research and practice. While there are often positive effects attributed with the trend, e.g. with respect to increased performance or motivation, not much attention has yet been given to the effects it has on stress of employees. In order to close this research gap, we conduct a qualitative single case study in the public sector. We derive four major stressors that are related to IT consumerization, i.e. 1) increased reachability, 2) lack of competence, 3) workflow changes, and 4) system redundancies. These stressors are discussed with respect to related theory concepts in IS. Moreover, they are used to derive recommendations for practitioners with respect to policy development and communication. Our paper contributes to the recent discussion on theoretical implications of IT consumerization effects
Cycle spectra of Hamiltonian graphs
AbstractWe prove that every Hamiltonian graph with n vertices and m edges has cycles with more than p−12lnp−1 different lengths, where p=m−n. For general m and n, there exist such graphs having at most 2⌈p+1⌉ different cycle lengths
Steigerung der P-Verfügbarkeit in pyrolysiertem Klärschlamm durch die Zugabe von Salzen beim Pyrolysieren
Durch die Pyrolyse von Klärschlamm entsteht ein hygienisiertes, kohlenstoffhaltiges Granulat mit hoher P-Konzentration. Der Phosphor in der Klärschlammkohle ist allerdings kaum pflanzenverfügbar. Durch den Zusatz von Chloriden (MgCl2, CaCl2) oder Biomasse aus Grünschnittabfall während der Pyrolyse des Klärschlamms wurde versucht, die Verfügbarkeit des Phosphors aus der Klärschlammkohle (KSK) zu steigern. In einem Gewächshausversuch mit Welschem Weidelgras wurde die Pflanzenverfügbarkeit aus der KSK geprüft. Die Düngewirkung der KSK wurde mit wasserlöslichem Ca(H2PO4)2 und weicherdigem Rohphosphat (Dolophos® 26) verglichen. Durch die Zugabe von Chloriden vor der Pyrolyse stieg die Düngewirkung der KSK zwar etwas an, sie blieb aber ähnlich gering wie die des Rohphosphats. Nur der wasserlösliche Mineraldünger steigerte die P-Aufnahme der Pflanzen signifikant
Cryoelectron tomography reveals periodic material at the inner side of subpellicular microtubules in apicomplexan parasites
Microtubules are dynamic cytoskeletal structures important for cell division, polarity, and motility and are therefore major targets for anticancer and antiparasite drugs. In the invasive forms of apicomplexan parasites, which are highly polarized and often motile cells, exceptionally stable subpellicular microtubules determine the shape of the parasite, and serve as tracks for vesicle transport. We used cryoelectron tomography to image cytoplasmic structures in three dimensions within intact, rapidly frozen Plasmodium sporozoites. This approach revealed microtubule walls that are extended at the luminal side by an additional 3 nm compared to microtubules of mammalian cells. Fourier analysis revealed an 8-nm longitudinal periodicity of the luminal constituent, suggesting the presence of a molecule interacting with tubulin dimers. In silico generation and analysis of microtubule models confirmed this unexpected topology. Microtubules from extracted sporozoites and Toxoplasma gondii tachyzoites showed a similar density distribution, suggesting that the putative protein is conserved among Apicomplexa and serves to stabilize microtubules
Rapid High Yield Production of Different Glycoforms of Ebola Virus Monoclonal Antibody
Fc-glycosylation of monoclonal antibodies (mAbs) has profound implications on the Fc-mediated effector functions. Alteration of this glycosylation may affect the efficiency of an antibody. However, difficulties in the production of mAbs with homogeneous N-glycosylation profiles in sufficient amounts hamper investigations of the potential biological impact of different glycan residues.Here we set out to evaluate a transient plant viral based production system for the rapid generation of different glycoforms of a monoclonal antibody. Ebola virus mAb h-13F6 was generated using magnICON expression system in Nicotiana benthamiana, a plant species developed for commercial scale production of therapeutic proteins. h-13F6 was co-expressed with a series of modified mammalian enzymes involved in the processing of complex N-glycans. Using wild type (WT) plants and the glycosylation mutant ΔXTFT that synthesizes human like biantennary N-glycans with terminal N-acetylglucosamine on each branch (GnGn structures) as expression hosts we demonstrate the generation of h-13F6 complex N-glycans with (i) bisected structures, (ii) core α1,6 fucosylation and (iii) β1,4 galactosylated oligosaccharides. In addition we emphasize the significance of precise sub Golgi localization of enzymes for engineering of IgG Fc-glycosylation.The method described here allows the efficient generation of a series of different human-like glycoforms at large homogeneity of virtually any antibody within one week after cDNA delivery to plants. This accelerates follow up functional studies and thus may contribute to study the biological role of N-glycan residues on Fcs and maximizing the clinical efficacy of therapeutic antibodies
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