265 research outputs found
Electronic and phononic properties of cinnabar: ab initio calculations and some experimental results
We report ab initio calculations of the electronic band structure, the
corresponding optical spectra, and the phonon dispersion relations of trigonal
alpha-HgS (cinnabar). The calculated dielectric functions are compared with
unpublished optical measurements by Zallen and coworkers. The phonon dispersion
relations are used to calculate the temperature and isotopic mass dependence of
the specific heat which has been compared with experimental data obtained on
samples with the natural isotope abundances of the elements Hg and S (natural
minerals and vapor phase grown samples) and on samples prepared from isotope
enriched elements by vapor phase transport. Comparison of the calculated
vibrational frequencies with Raman and ir data is also presented. Contrary to
the case of cubic beta-HgS (metacinnabar), the spin-orbit splitting of the top
valence bands at the Gamma-point of the Brillouin zone (Delta_0) is positive,
because of a smaller admixture of 5d core electrons of Hg. Calculations of the
lattice parameters, and the pressure dependence of Delta_0 and the
corresponding direct gap E_0~2eV are also presented. The lowest absorption edge
is confirmed to be indirect.Comment: 13 pages, 15 figure
An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows
The ability of some bird species to pull up meat hung on a string is a famous example of spontaneous animal problem solving. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination. An operant conditioning account, in contrast, would claim that this spontaneity is due to each action in string pulling being reinforced by the meat moving closer and remaining closer to the bird on the perch. We presented experienced and naïve New Caledonian crows with a novel, visually restricted string-pulling problem that reduced the quality of visual feedback during string pulling. Experienced crows solved this problem with reduced efficiency and increased errors compared to their performance in standard string pulling. Naïve crows either failed or solved the problem by trial and error learning. However, when visual feedback was available via a mirror mounted next to the apparatus, two naïve crows were able to perform at the same level as the experienced group. Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle
Des Staats-klugen Plinii Hoff- und Bürgerliche Briefe : In die Teutsche Helden-Sprache übersetzt, Auch mit nützlichen Anmerckungen und Registern versehen
von Joanne Sartorio, Eloqv. & Poës. Prof. Publ. in DantzigTitelbl. in Rot- und SchwarzdruckAus dem Latein. übers.Nebent.: Des Staats- Klugen Plinii Hoff- und Bürgerliche Send-Schreibe[n] in die deutsche Helden-Sprache übersetztVorlageform des Erscheinungsvermerks: Lejpzjg, Jm Verlag Johann Ludewig Gleditsch und Moritz Georg Weidmanns. Anno Christi 1712
Bearbeitung und Einführung. resp. Veranlassung zu höherer Genehmigung und Annahme einer gemeinschaftlichen Pharmakopöe für ganz Deutschland
Historia mundi naturalis C. Plinii Secvndi: Hoc Est: Amplissimvm, Lvcidissimvm, Perspiciacissimvmqve, Nec Non Plane Mirandvm Totivs Vniversi, Rervmqve Natvralivm Specvlvm ... In Libros XXXVII. Distribvta, Vivisqve Imaginibvs Illvstrata atque vero proprioque naturae nitori labore impensisque Sigismundi Feyerabenij hoc nouo ... His Breves Ervditaeqve In Margine Doctissimorvm Virorvm Castigationes: Sigismundi Gelenij quoq[ue] perspicuae atque perutiles animaduersiones accesserunt. Cum Indice rerum & verborum locupletissimo
http://www.ester.ee/record=b4536370*es
Liber II: C. Plinii De Mvndi Historia, Cvm Commentariis Iacobi Milichii, Diligenter conscriptis & recognitis. Cum Indice in fine adiecto
http://www.ester.ee/record=b4091269*es
De medicina / digital edition published by digilibLT digital library of late-Latin texts
Correzione linguistica David Paniagua
Codifica XML David Paniagua
HomePage del progetto: https://digiliblt.uniupo.it/
Documentazione: https://digiliblt.uniupo.it/progetto.ph
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