8,321 research outputs found
GLSM realizations of maps and intersections of Grassmannians and Pfaffians
In this paper we give gauged linear sigma model (GLSM) realizations of a
number of geometries not previously presented in GLSMs. We begin by describing
GLSM realizations of maps including Veronese and Segre embeddings, which can be
applied to give GLSMs explicitly describing constructions such as the
intersection of one hypersurface with the image under some map of another. We
also discuss GLSMs for intersections of Grassmannians and Pfaffians with one
another, and with their images under various maps, which sometimes form exotic
constructions of Calabi-Yaus, as well as GLSMs for other exotic Calabi-Yau
constructions of Kanazawa. Much of this paper focuses on a specific set of
examples of GLSMs for intersections of Grassmannians G(2,N) with themselves
after a linear rotation, including the Calabi-Yau case N=5. One phase of the
GLSM realizes an intersection of two Grassmannians, the other phase realizes an
intersection of two Pfaffians. The GLSM has two nonabelian factors in its gauge
group, and we consider dualities in those factors. In both the original GLSM
and a double-dual, one geometric phase is realized perturbatively (as the
critical locus of a superpotential), and the other via quantum effects.
Dualizing on a single gauge group factor yields a model in which each geometry
is realized through a simultaneous combination of perturbative and quantum
effects.Comment: LaTeX, 50 pages; v2: typos fixed and a few comments on other
dualities adde
Medizinische probleme und physikalische grundlagen der kernreaktoren
Die Autoren berichten Uber die Forschungen mit Hilfe von Kernreaktoren auf dem Grenzgebiet der Medizin und Strahlenphysik (Reaktorphysik). Es wurden kurz ihre eigene bisherige Ergebnisse, das Ziel dieser Forschungen und einzelne Zukunftsmoglichkeiten erwahnt. Nachdem wurden in mehreren Teilen die Kernreaktoren beschrieben. 1m erstem Teil werden die allgemeinen physikalischen Grundlagen eines
Kernreaktors dargestellt. Mit Hilfe der Kernkrafte und der Bindungsenergie wird gezeigt, wieso eine Kernspaltung auftreten kann und wieso aus den nicht spaltbaren Isotopen U-238 die spaltbaren Isotope Pu-239 bzw. U-233 "erbrutet" werden konnen. -Das Zustandekommen einer Kettenreaktion,
die die Grundlage einer Energiegewinnung aus der Kernspaltung ist, wird erlautert, wobei sich auf die Wechselwirkungen zwischen Atomkernen und Neutronen hingewiesen wird. 1m AnschluB daran werden die Vorgange im Kernreaktor im Einzelnen naher verfolgt. Dabei werden mehrere Moglichkeiten beschriebenk die es erlauben, die Neutronenzahl, die fur die Kettenreaktion entscheidend ist, zu erhohen. Einer allgemeinen Dbersicht uber die verschiedenen Reaktortypen und ihreu Einsatz in Forschung und Industrie schlie13t sich eine Beschreibung verschiedener deutscher Reaktoren und ihrer speziellen Eigenschaften und Vorteile an. Zum SchluB wird noch besonders auf die groBen Projekte der Entwicklung von Thorium-Brutern und von schnellen Brutern eingegangen.</p
Identification of Bare-Airframe Dynamics from Closed-Loop Data Using Multisine Inputs and Frequency Responses
Amethod is presented for computing multiple-input multiple-output frequency responses of bare-airframe dynamics for systems excited using orthogonal phase-optimized multisines and including correlated data arising from control mixing or feedback control. The estimation was posed as the solution to an underdetermined system of linear equations, for which additional information was supplied using interpolation of the frequency responses. A simulation model of the NASA T-2 aircraft having two inputs and two outputs was used to investigate the method in the open-loop configuration and under closed-loop control. The method was also applied to flight test data from the X-56A aeroelastic demonstrator having five inputs and ten outputs and flying under closed-loop control with additional control allocation mixing. Results demonstrated that the proposed method accurately estimates the bare airframe frequency responses in the presence of correlated data from control mixing and feedback control. Results also agreed with estimates obtained using different methods that are less sensitive to correlated inputs
Strahlenpharmakologische untersuchungen mit neutronen an eisenhaltigen praparaten im Siemens unterrichtsreaktor SUR 100
Die stark eisenhaltigen Praparate Ferrlecit, Kobaltjerrlecit, Ferrojolsan, Ferrojolcamma und Irradian wurden im Siemens Unterrichtsreaktor SUR 100 des Instituts fur Kernenergetikder Universitat Struttgart und der Technischen Universitat, Berlin mit einem NeutronenfluB von ca. 5.l06n/cm2 sec bestrahlt. Es ollte dabei untersucht werden, wie stark eisenhaltige Praparate mit diesem Reaktor aktiviert werden konnen. Es wird festgestellt, daB Eisen praktisch kaum aktiviert wird. Die Ergebnisse zeigen, daB nur das Kobattjerrlecit und das Irradian starker durch Neutrosen aktiviert werden. Die hohere Aktivitat des Kobaltjerrlecit wird auf die darin enthaltenen Elemente Mangan, Kupfer und Kobalt zuruckgefuhrt, die mit thermischen Neutronen gut aktivierbar sind. Die hohere Aktivitat des Irradian geht hauptsachlich auf β-Zerfalle zuruck. Das Phosphorisotop P-32 tragt einen groβen Anteil dazu bei. De rβ-Untergrund des Irradian bei hohen Energien, der mit einer kleinen Halbwertszeitabklingt, ist
durch keines der angefuhrten Elemente im Irradian erklarbar. Der Mn-56Peak im Spektrum ist gut erkennbar, durch den β-Untergrund wird er aber zu einer hoheren Energie hin verschoben.</p
Ethyl Zinc β-Ketoiminates and β-Amidoenoates: Influence of Precursor Design on the Properties of Highly Conductive Zinc Oxide Thin Films from Aerosol-Assisted Chemical Vapour Deposition
Highly transparent (>85 %) and conductive (1.086×10-3  Ω cm) zinc oxide thin films have been deposited from specifically selected precursors allowing us to establish a direct correlation between their molecular structure and the optoelectronic properties of the deposited films. Mono-ligated ethyl zinc compounds of varying steric bulk: [EtZn(OC(Me)CH(Me)N(i Pr))]2 (1), [EtZn(OC(OEt)CH(Me)N(i Pr))]2 (2) and [EtZn(OC(OEt)CH(CH3 )N(Dipp))]2 (3) were compared with the related bis-ligated zinc complexes [Zn(OC(Me)CH(Me)N(i Pr))2 ] (4), [Zn(OC(OEt)CH(Me)N(i Pr))2 ] (5) and [Zn(OC(OEt)CH(Me)N(Dipp))2 ] (6). In all cases bulkier ligands resulted in poorer electronic properties of deposited films, whilst all mono-ligated compounds were shown as superior precursors. All complexes were characterised by 1 H and 13 C{1 H} NMR and elemental analysis, with the structure of 6 determined by single crystal X-ray diffraction. Zinc oxide films were deposited from single and dual source (with methanol) reactions of these precursors, and analysed via XRD, XPS and EDX. Optoelectronic properties were investigated through UV/vis spectroscopy and Hall effect measurements, and morphology was examined via SEM. Tauc plots from UV/vis data indicated that Film A showed the lowest band gap of 3.31 eV. Varying the elemental composition of the precursors led to changes in the elemental composition of the resultant films, as well as changes in their structural and optoelectronic properties. Using this approach of precursor design, we have been able to tune single source precursors towards zinc oxide to deposit films with specific properties
Calculations for Mirror Symmetry with D-branes
We study normal functions capturing D-brane superpotentials on several one-
and two-parameter Calabi-Yau hypersurfaces and complete intersections in
weighted projective space. We calculate in the B-model and interpret the
results using mirror symmetry in the large volume regime, albeit without
identifying the precise A-model geometry in all cases. We identify new classes
of extensions of Picard-Fuchs equations, as well as a novel type of topology
changing phase transition involving quantum D-branes. A 4-d domain wall which
is obtained in one region of closed string moduli space from wrapping a
four-chain interpolating between two Lagrangian submanifolds is, for other
values of the parameters, represented by a disk ending on a single Lagrangian.Comment: 42 page
Phylogenetic analyses of peanut resistance gene candidates and screening of different genotypes for polymorphic markers
AbstractThe nucleotide-binding-site-leucine-rich-repeat (NBS–LRR)-encoding gene family has attracted much research interest because approximately 75% of the plant disease resistance genes that have been cloned to date are from this gene family. Here, we describe a collection of peanut NBS–LRR resistance gene candidates (RGCs) isolated from peanut (Arachis) species by mining Gene Bank data base. NBS–LRR sequences assembled into TIR-NBS-LRR (75.4%) and non-TIR-NBS-LRR (24.6%) subfamilies. Total of 20 distinct clades were identified and showed a high level of sequence divergence within TIR-NBS and non-TIR-NBS subfamilies. Thirty-four primer pairs were designed from these RGC sequences and used for screening different genotypes belonging to wild and cultivated peanuts. Therefore, peanut RGC identified in this study will provide useful tools for developing DNA markers and cloning the genes for resistance to different pathogens in peanut
Optimised patient information materials and recruitment to a study of behavioural activation in older adults : an embedded study within a trial [version 1; peer review: awaiting peer review]
YesPrinted participant information about randomised controlled trials is often long, technical and difficult to navigate. Improving information materials is possible through optimisation and user-testing, and may impact on participant understanding and rates of recruitment. Methods: A study within a trial (SWAT) was undertaken within the CASPER trial. Potential CASPER participants were randomised to receive either the standard trial information or revised information that had been optimised through information design and user testing. Results: A total of 11,531 patients were randomised in the SWAT. Rates of recruitment to the CASPER trial were 2.0% in the optimised information group and 1.9% in the standard information group (odds ratio 1.027; 95% CI 0.79 to 1.33; p=0.202). Conclusions: Participant information that had been optimised through information design and user testing did not result in any change to rate of recruitment to the host trial. Registration: ISRCTN ID ISRCTN02202951; registered on 3 June 2009.UK National Institute of Health Research Health Technology Assessment Programme (project number 08/19/04)This article is included in the Studies Within A Trial (SWAT) collection (https://f1000research.com/collections/swat
The Cold and Hot Gas Content of Fine-Structure E and S0 Galaxies
We investigate trends of the cold and hot gas content of early-type galaxies
with the presence of optical morphological peculiarities, as measured by the
fine-structure index (Sigma). HI mapping observations from the literature are
used to track the cold-gas content, and archival ROSAT PSPC data are used to
quantify the hot-gas content. We find that E and S0 galaxies with a high
incidence of optical peculiarities are exclusively X-ray underluminous and,
therefore, deficient in hot gas. In contrast, more relaxed galaxies with little
or no signs of optical peculiarities span a wide range of X-ray luminosities.
That is, the X-ray excess anticorrelates with Sigma. There appears to be no
similar trend of cold-gas content with either fine-structure index or X-ray
content. The fact that only apparently relaxed E and S0 galaxies are strong
X-ray emitters is consistent with the hypothesis that after strong disturbances
such as a merger hot-gas halos build up over a time scale of several gigayears.
This is consistent with the expected mass loss from stars.Comment: 12 pages, latex, 5 figures. Accepted for publication in A
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