@article{BillerbeckBarnatKnutzen2016, author = {Billerbeck, Katrin and Barnat, Miriam and Knutzen, S{\"o}nke}, title = {Kompetenzorientierung auf dem Pr{\"u}fstand. Erprobung von Indikatoren f{\"u}r den Kulturwandel}, series = {Die Hochschullehre}, volume = {2016}, journal = {Die Hochschullehre}, number = {16}, publisher = {WBV Media}, address = {Bielefeld}, issn = {2199-8825}, doi = {10.3278/HSL1616W}, pages = {16}, year = {2016}, abstract = {Der Beitrag fokussiert die Frage nach dem Stand des durch die Bologna-Reform angestoßenen Kulturwandels im Hinblick auf Kompetenzorientierung am Beispiel der Technischen Universit{\"a}t Hamburg (TUHH). An der TUHH wird bereits seit einigen Jahren daran gearbeitet, die Lehre grundlegend neu auszurichten. Hierf{\"u}r setzt das hochschuldidaktische "Zentrum f{\"u}r Lehre und Lernen" (ZLL) verschiedene Maßnahmen ein, wie z.B. eine finanzielle und didaktische Unterst{\"u}tzung von Lehrenden bei der Umstellung ihrer Veranstaltungen, Weiterqualifizierungsangebote und Informationsmaterial. Die Maßnahmen ebenso wie die innovierten Veranstaltungen werden von Lehrenden und Studierenden gut evaluiert. Nach dem Ansatz des Constructive Alignments l{\"a}sst sich jedoch davon ausgehen, dass der Bereich der Pr{\"u}fungen f{\"u}r eine Einsch{\"a}tzung des Status Quo der Kompetenzorientierung besonders relevant ist. Dieser wird deshalb anhand der beiden Kriterien Pr{\"u}fungsformate und Schwierigkeitsstufen von Pr{\"u}fungsaufgaben n{\"a}her beleuchtet, die eng mit der Kompetenzorientierung zusammen h{\"a}ngen. Ergebnisse hierzu aus einer universit{\"a}tsweiten Datenbank zur Studienorganisation sowie aus einer Online-Umfrage unter Studierenden weisen darauf hin, dass das Pr{\"u}fungsformat "Klausur" nach wie vor am st{\"a}rksten verbreitet ist; zugleich sind die Studierenden nach einer Selbsteinsch{\"a}tzung in Pr{\"u}fungen vorrangig mit Aufgaben auf den Taxonomieniveaus "Wiedergeben" und "Anwenden" konfrontiert. Dies l{\"a}sst sich als Hinweis darauf interpretieren, dass es im Hinblick auf eine Kompetenzorientierung in den Pr{\"u}fungen noch weiteren Ver{\"a}nderungsbedarf gibt.}, language = {de} } @article{PaulssenLengkeekLeetal.2016, author = {Paulßen, Elisabeth and Lengkeek, Nigel A. and Le, Van So and Pellegrini, Paul A. and Greguric, Ivan and Weiner, Ron}, title = {The role of additives in moderating the influence of Fe(III) and Cu(II) on the radiochemical yield of [⁶⁸Ga(DOTATATE)]}, series = {Applied Radiation and Isotopes}, volume = {107}, journal = {Applied Radiation and Isotopes}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-9800}, doi = {10.1016/j.apradiso.2015.09.008}, pages = {13 -- 16}, year = {2016}, abstract = {[⁶⁸Ga(DOTATATE)] has demonstrated its clinical usefulness. Both Fe³⁺ and Cu²⁺, potential contaminants in Gallium-68 generator eluent, substantially reduce the radiochemical (RC) yield of [⁶⁸Ga(DOTATATE)] if the metal/ligand ratio of 1:1 is exceeded. A variety of compounds were examined for their potential ability to reduce this effect. Most had no effect on RC yield. However, addition of phosphate diminished the influence of Fe³⁺ by likely forming an insoluble iron salt. Addition of ascorbic acid reduced Cu²⁺ and Fe³⁺ to Cu⁺ and Fe²⁺ respectively, both of which have limited impact on RC yields. At low ligand amounts (5 nmol DOTATATE), the addition of 30 nmol phosphate (0.19 mM) increased the tolerance of Fe3⁺ from 4 nmol to 10 nmol (0.06 mM), while the addition of ascorbic acid allowed high RC yields (>95\%) in the presence of 40 nmol Fe³⁺ (0.25 mM) and 100 nmol Cu²⁺ (0.63 mM). The effect of ascorbic acid was highly pH-dependant, and gave optimal results at pH 3.}, language = {en} } @article{InfantinoPaulssenMostaccietal.2016, author = {Infantino, Angelo and Paulßen, Elisabeth and Mostacci, Domiziano and Schaffer, Paul and Trinczek, Michael and Hoehr, Cornelia}, title = {Assessment of the production of medical isotopes using the Monte Carlo code FLUKA: Simulations against experimental measurements}, series = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, volume = {366}, journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-9584}, doi = {10.1016/j.nimb.2015.10.067}, pages = {117 -- 123}, year = {2016}, abstract = {The Monte Carlo code FLUKA is used to simulate the production of a number of positron emitting radionuclides, ¹⁸F, ¹³N, ⁹⁴Tc, ⁴⁴Sc, ⁶⁸Ga, ⁸⁶Y, ⁸⁹Zr, ⁵²Mn, ⁶¹Cu and ⁵⁵Co, on a small medical cyclotron with a proton beam energy of 13 MeV. Experimental data collected at the TR13 cyclotron at TRIUMF agree within a factor of 0.6 ± 0.4 with the directly simulated data, except for the production of ⁵⁵Co, where the simulation underestimates the experiment by a factor of 3.4 ± 0.4. The experimental data also agree within a factor of 0.8 ± 0.6 with the convolution of simulated proton fluence and cross sections from literature. Overall, this confirms the applicability of FLUKA to simulate radionuclide production at 13 MeV proton beam energy.}, language = {en} } @article{Bernecker2016, author = {Bernecker, Andreas}, title = {Divided we reform? Evidence from US welfare policies}, series = {Journal of Public Economics}, volume = {142}, journal = {Journal of Public Economics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0047-2727}, doi = {10.1016/j.jpubeco.2016.08.003}, pages = {24 -- 38}, year = {2016}, abstract = {Divided government is often thought of as causing legislative deadlock. I investigate the link between divided government and economic reforms using a novel data set on welfare reforms in US states between 1978 and 2010. Panel data regressions show that, under divided government, a US state is around 25\% more likely to adopt a welfare reform than under unified government. Several robustness checks confirm this counter-intuitive finding. Case study evidence suggests an explanation based on policy competition between governor, senate, and house.}, language = {en} } @article{VergePoettgenAltherretal.2016, author = {Verg{\´e}, Angela and P{\"o}ttgen, Philipp and Altherr, Lena and Ederer, Thorsten and Pelz, Peter F.}, title = {Lebensdauer als Optimierungsziel: Algorithmische Struktursynthese am Beispiel eines hydrostatischen Getriebes}, series = {O+P - {\"O}lhydraulik und Pneumatik}, volume = {60}, journal = {O+P - {\"O}lhydraulik und Pneumatik}, number = {1-2}, editor = {Greuloch, Ivo and Weber, Manfred and Meier, Miles}, publisher = {Vereinigte Fachverl.}, address = {Mainz}, issn = {1614-9602}, pages = {114 -- 121}, year = {2016}, abstract = {Verf{\"u}gbarkeit und Nachhaltigkeit sind wichtige Anforderungen bei der Planung langlebiger technischer Systeme. Meist werden bei Lebensdaueroptimierungen lediglich einzelne Komponenten vordefinierter Systeme untersucht. Ob eine optimale Lebensdauer eine g{\"a}nzlich andere Systemvariante bedingt, wird nur selten hinterfragt. Technical Operations Research (TOR) erlaubt es, aus Obermengen technischer Systeme automatisiert die lebensdaueroptimale Systemstruktur auszuw{\"a}hlen. Der Artikel zeigt dies am Beispiel eines hydrostatischen Getriebes.}, language = {de} } @article{PeloniCeriottiDachwald2016, author = {Peloni, Alessandro and Ceriotti, Matteo and Dachwald, Bernd}, title = {Solar-sail trajectory design for a multiple near-earth-asteroid rendezvous mission}, series = {Journal of Guidance, Control, and Dynamics}, volume = {39}, journal = {Journal of Guidance, Control, and Dynamics}, number = {12}, publisher = {AIAA}, address = {Reston, Va.}, issn = {0731-5090}, doi = {10.2514/1.G000470}, pages = {2712 -- 2724}, year = {2016}, abstract = {The scientific interest for near-Earth asteroids as well as the interest in potentially hazardous asteroids from the perspective of planetary defense led the space community to focus on near-Earth asteroid mission studies. A multiple near-Earth asteroid rendezvous mission with close-up observations of several objects can help to improve the characterization of these asteroids. This work explores the design of a solar-sail spacecraft for such a mission, focusing on the search of possible sequences of encounters and the trajectory optimization. This is done in two sequential steps: a sequence search by means of a simplified trajectory model and a set of heuristic rules based on astrodynamics, and a subsequent optimization phase. A shape-based approach for solar sailing has been developed and is used for the first phase. The effectiveness of the proposed approach is demonstrated through a fully optimized multiple near-Earth asteroid rendezvous mission. The results show that it is possible to visit five near-Earth asteroids within 10 years with near-term solar-sail technology.}, language = {en} } @article{HoerenbaumLaumannProkop2016, author = {H{\"o}renbaum, Christoph and Laumann, J{\"o}rg and Prokop, Ines}, title = {Zur Anwendung des Eurocode 3 Teil 1-2 f{\"u}r die Heißbemessung und Anregungen f{\"u}r dessen Novellierung}, series = {Stahlbau}, volume = {85}, journal = {Stahlbau}, number = {6}, publisher = {Ernst \& Sohn GmbH}, address = {Berlin}, issn = {1437-1049}, doi = {10.1002/stab.201610382}, pages = {429 -- 434}, year = {2016}, abstract = {Die Eurocodes werden bis zum Jahr 2020 im Europ{\"a}ischen Komitee f{\"u}r Normung (CEN), Technisches Komitee TC 250, {\"u}berarbeitet. In Vorbereitung auf die Eurocode-Novellierung haben engagierte Ingenieure im Rahmen der Initiative PraxisRegeln Bau (PRB) die f{\"u}r die praktische Anwendung h{\"a}ufig genutzten Teile des Eurocode 3 untersucht. Mit dem Ziel, die Praxistauglichkeit des Eurocode 3 f{\"u}r die Heißbemessung zu verbessern, wurden die bestehende Norm EN 1993 Teil 1-2 insbesondere in Bezug auf die Anwenderfreundlichkeit analysiert und Vorschl{\"a}ge f{\"u}r die europ{\"a}ische Novellierung erarbeitet. Die Analysen zeigen, dass durch Umstrukturierungen und durch die Einf{\"u}hrung von Tabellen die Verst{\"a}ndlichkeit und Anwenderfreundlichkeit der Regeln f{\"u}r die Heißbemessung bedeutend erh{\"o}ht werden k{\"o}nnen.}, language = {de} } @article{LeversStaatLaack2016, author = {Levers, A. and Staat, Manfred and Laack, Walter van}, title = {Analysis of the long-term effect of the MBST® nuclear magnetic resonance therapy on gonarthrosis}, series = {Orthopedic Practice}, volume = {47}, journal = {Orthopedic Practice}, number = {11}, pages = {521 -- 528}, year = {2016}, language = {en} } @article{KosterScheidweilerTieves2016, author = {Koster, Arie and Scheidweiler, Robert and Tieves, Martin}, title = {A flow based pruning scheme for enumerative equitable coloring algorithms}, series = {A flow based pruning scheme for enumerative equitable coloring algorithms}, journal = {A flow based pruning scheme for enumerative equitable coloring algorithms}, doi = {10.48550/arXiv.1607.08754}, pages = {1 -- 30}, year = {2016}, abstract = {An equitable graph coloring is a proper vertex coloring of a graph G where the sizes of the color classes differ by at most one. The equitable chromatic number is the smallest number k such that G admits such equitable k-coloring. We focus on enumerative algorithms for the computation of the equitable coloring number and propose a general scheme to derive pruning rules for them: We show how the extendability of a partial coloring into an equitable coloring can be modeled via network flows. Thus, we obtain pruning rules which can be checked via flow algorithms. Computational experiments show that the search tree of enumerative algorithms can be significantly reduced in size by these rules and, in most instances, such naive approach even yields a faster algorithm. Moreover, the stability, i.e., the number of solved instances within a given time limit, is greatly improved. Since the execution of flow algorithms at each node of a search tree is time consuming, we derive arithmetic pruning rules (generalized Hall-conditions) from the network model. Adding these rules to an enumerative algorithm yields an even larger runtime improvement.}, language = {en} } @article{BeckenbachScheidweiler2016, author = {Beckenbach, Isabel and Scheidweiler, Robert}, title = {Perfect ƒ-Matchings and ƒ-Factors in Hypergraphs - A Combinatorial Approach}, series = {Discrete Mathematics}, volume = {240}, journal = {Discrete Mathematics}, number = {10}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2192-7782}, doi = {10.1016/j.disc.2017.05.005}, pages = {2499 -- 2506}, year = {2016}, abstract = {We prove characterizations of the existence of perfect ƒ-matchings in uniform mengerian and perfect hypergraphs. Moreover, we investigate the ƒ-factor problem in balanced hypergraphs. For uniform balanced hypergraphs we prove two existence theorems with purely combinatorial arguments, whereas for non-uniform balanced hypergraphs we show that the ƒ-factor problem is NP-hard.}, language = {en} }