Structural model optimization using statistical evaluation

The results of research in applying statistical methods to the problem of structural dynamic system identification are presented. The study is in three parts: a review of previous approaches by other researchers, a development of various linear estimators which might find application, and the design and development of a computer program which uses a Bayesian estimator. The method is tried on two models and is successful where the predicted stiffness matrix is a proper model, e.g., a bending beam is represented by a bending model. Difficulties are encountered when the model concept varies. There is also evidence that nonlinearity must be handled properly to speed the convergence

Ertragsentwicklung von Erbsen sowie Sommergerste in Reinsaat und in Mischung mit Leindotter oder Koriander im Ökologischen Landbau

Mischkulturen können unterschiedliche Wachstumsbedingungen besser ausschöpfen als Monokulturen. Im Gemenge mit Leguminosen können Nicht-Leguminosen überschüssigen Stickstoff aus der Bodenlösung aufnehmen. Ein ökonomischer Zusatzertrag wird bei einer Beimengung von Leindotter zu Erbsen oder Sommergerste diskutiert. Erbsenreinsaaten erreichten im Vergleich zu beiden Leindotter-Varianten gesichert höhere Erträge; Erbsen mit resp. ohne Koriander unterschieden sich nicht. Sommergerste – Reinsaaten waren bezüglich dem Ertrag den Mischungen mit Leindotter überlegen; Koriander wurde von der Sommergerste vollständig unterdrückt. Abschließend kann festgehalten werden, dass unter limitierenden Niederschlägen im pannonischen Klimaraum dem Mischkulturanbau enge Grenzen gesetzt sind

CONTINUED EASTWARD RANGE EXPANSION OF BLACK PHOEBES (SAYORNIS NIGRICANS) IN SOUTHERNMOST TEXAS

ABSTRACT—We observed black phoebe (Sayornis nigricans) nests, breeding pairs, and juveniles in Cameron County, Texas, in 2017. Our first confirmed nesting records in Cameron County document a continued eastward range expansion by black phoebes. RESUMEN—En el 2017, observamos nidos, parejas reproductoras y juveniles del p´ajaro mosquero negro (Sayornis nigricans) en el condado de Cameron, Texas. Los primeros registros confirmados de reproducci ´on en el condado de Cameron son evidencia de una continua expansi´on hacia el este de la distribuci ´on geogr´afica del mosquero negro

Preharvest Chitosan and Postharvest UV Irradiation Treatments Suppress Gray Mold of Table Grapes

The effectiveness of chitosan treatment of table grapes, alone or in combination with ultraviolet-C (UV-C) radiation, to control postharvest gray mold caused by Botrytis cinerea, was determined in California, United States. The influence of these treatments on catechin and resveratrol contents and chitinase activity in grape berry skins also was assessed. Clusters of cvs. Thompson Seedless, Autumn Black, and Emperor were sprayed in the vineyard with 1% chitosan, then harvested daily for 5 days. Promptly after harvest, they were inoculated with B. cinerea. Decay incidence and disease severity were significantly reduced by chitosan, which was most effective on berries harvested 1 or 2 days after treatment. In another experiment, grape berries were sprayed in the vineyard with chitosan, harvested 2 days later, irradiated for 5 min with UV-C (0.36 J/cm2), and inoculated with B. cinerea 2 days later. Combined chitosan and UV-C treatments applied to cv. Autumn Black or selection B36-55 were synergistic in reducing gray mold incidence and severity compared with either treatment alone. Preharvest chitosan treatment increased neither concentration of catechin or resveratrol nor activity of chitinase in berry skin. Conversely, UV-C irradiation, alone or combined with chitosan treatment, induced catechin in cv. Autumn Black berries and trans-resveratrol in both cv. Autumn Black and selection B36-55

O ESPAÇO-MOVIMENTO DO CICLISTA: SEGUINDO O CICLISTA ANÔNIMO

A presente dissertação se constitui de uma busca por identificar e investigar a subjetividade da relação cotidiana da prática de pedalar com o espaço urbano. A partir do desenvolvimento conceitual do binômio espaço-movimento, originalmente exposto por Paola B. Jacques, propõe-se uma investigação do caminho daqueles que pedalam pela cidade anonimamente e têm a bicicleta como meio de transporte num cotidiano de subsistência. Parte-se de uma concepção móvel da cidade e persegue-se o objeto nas relações do 'entre', do 'enquanto', do 'mover-se', valorizando o deslocamento como um modo de habitar a cidade, objetivando contribuir para estudos da mobilidade ativa e da produção do espaço urbano. Para tanto foi desenvolvido uma metodologia de observação participativa dinâmica aos movimentos dos ciclistas anônimos. Palavras-chave: Espaço-movimento, Bicicleta, Cidade, cotidiano

Magneto-elastic torsional oscillations of magnetars

We extend a general-relativistic ideal magneto-hydrodynamical code to include the effects of elasticity. Using this numerical tool we analyse the magneto-elastic oscillations of highly magnetised neutron stars (magnetars). In simulations without magnetic field we are able to recover the purely crustal shear oscillations within an accuracy of about a few per cent. For dipole magnetic fields between 5 x 10^13 and 10^15 G the Alfv\'en oscillations become modified substantially by the presence of the crust. Those quasi-periodic oscillations (QPOs) split into three families: Lower QPOs near the equator, Edge QPOs related to the last open field line and Upper QPOs at larger distance from the equator. Edge QPOs are called so because they are related to an edge in the corresponding Alfv\'en continuum. The Upper QPOs are of the same kind, while the Lower QPOs are turning-point QPOs, related to a turning point in the continuous spectrum.Comment: 6 pages, 1 figure, 1 table, Proceedings of NEB14, to appear in J. Phys.: Conf. Se

Three-dimensional Models of Core-collapse Supernovae From Low-mass Progenitors With Implications for Crab

We present 3D full-sphere supernova simulations of non-rotating low-mass (~9 Msun) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions [~(0.5-1.0)x 10^{50} erg] of iron-core progenitors at the low-mass end of the core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB) progenitor with an oxygen-neon-magnesium core that collapses and explodes as electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN models is modelled self-consistently using the Vertex-Prometheus code, whereas the ECSN explosion is modelled using parametric neutrino transport in the Prometheus-HOTB code, choosing different explosion energies in the range of previous self-consistent models. The sAGB and LMCCSN progenitors that share structural similarities have almost spherical explosions with little metal mixing into the hydrogen envelope. A LMCCSN with less 2nd dredge-up results in a highly asymmetric explosion. It shows efficient mixing and dramatic shock deceleration in the extended hydrogen envelope. Both properties allow fast nickel plumes to catch up with the shock, leading to extreme shock deformation and aspherical shock breakout. Fallback masses of <~5x10^{-3} Msun have no significant effects on the neutron star (NS) masses and kicks. The anisotropic fallback carries considerable angular momentum, however, and determines the spin of the newly-born NS. The LMCCSNe model with less 2nd dredge-up results in a hydrodynamic and neutrino-induced NS kick of >40 km/s and a NS spin period of ~30 ms, both not largely different from those of the Crab pulsar at birth.Comment: 47 pages, 27 figures, 6 tables; minor revisions, accepted by MNRA

Ionizing Photon Emission Rates from O- and Early B-type Stars and Clusters

We present new computations of the ionizing spectral energy distributions (SEDs) and Lyman continuum (Lyc) and HeI continuum photon emission rates, for hot O-type and early B-type stars. We consider solar metallicity stars, with effective temperatures ranging from 25,000 to 55,000 K and surface gravities (cm s^-2) logg ranging from 3 to 4, covering the full range of spectral types and luminosity classes for hot stars. We use our updated (WM-basic) code to construct radiation-driven wind atmosphere models for hot stars. Our models include the coupled effects of hydrodynamics and non-LTE radiative transfer in spherically outflowing winds, including the detailed effects of metal line blocking and line blanketing on the radiative transfer and energy balance. We incorporate our hot-star models into our population synthesis code (STARS), and we compute the time-dependent SEDs and resulting Lyc and HeI emission rates for evolving star clusters. We present results for continuous and impulsive star formation for a range of assumed stellar initial mass functions.Comment: 23 pages, 7 figures. To appear in the Astrophysical Journal. For grid of star models see ftp://wise3.tau.ac.il/pub/star

Research with real photons at the MAMI 1.6 GeV electron accelerator

The A2-CB Collaboration at Mainz is studying the structure of hadrons by meson photoproduction using unpolarised, linearly polarised and circularly polarised photons with energies up to 1.6 GeV. Photons are energy-tagged using the Glasgow-Mainz tagged photon spectrometer and a new high-energy end-point tagger which allows η’ reactions to be studied. Reaction products are detected in a ~4π detector consisting of the Crystal Ball detector and TAPS forward wall. Transverse or longitudinally polarised proton targets are available and new techniques have been developed to measure the polarisation of recoiling protons. These facilities have allowed an extensive programme of double-polarisation meson-photoproduction experiments to be carried out to search for so-called “missing baryon resonances” on proton and deuteron targets. Searches have also been carried out to investigate narrow resonances in the η-photoproduction channel at invariant masses around 1680 MeV. Coherent π0 production measurements have been used to estimate the neutron skin thickness in 208Pb. This paper presents selected highlights from the A2-CB collaboration research programme at MAMI