A Raman spectroscopic study of a hydrated molybdate mineral ferrimolybdite, Fe2(MoO4)3·7–8H2O

Raman spectra of two well-defined ferrimolybdite samples, Fe23+(Mo6+O4)3·7–8H2O, from the Krupka deposit (northern Bohemia, Czech Republic) and Hůrky near Rakovník occurrence (central Bohemia, Czech Republic) were studied and tentatively interpreted. Observed bands were assigned to the stretching and bending vibrations of molybdate anions, Fe–O units and water molecules. Number of Raman and infrared bands assigned to (MoO4)2− units and water molecules proved that symmetrically (structurally) nonequivalent (MoO4)2− and H2O are present in the crystal structure of ferrimolybdite. Approximate O–H⋯O hydrogen bond lengths (2.80–2.73 Å) were inferred from the published infrared spectra.

The hardness of revising defeasible preferences

Non-monotonic reasoning typically deals with three kinds of knowledge. Facts are meant to describe immutable statements of the environment. Rules define relationships among elements. Lastly, an ordering among the rules, in the form of a superiority relation, establishes the relative strength of rules. To revise a non-monotonic theory, we can change either one of these three elements. We prove that the problem of revising a non-monotonic theory by only changing the superiority relation is a NP-complete problem.

Portrait of Molling and Sanger (Loewy) families on vacation; Marienbad Portraits Family

Therese Molling (1890-1981) is in back row in white dress, to her left is her mother Henny Molling nee Meyerhof (1864-1934), her husband (and Therese's father) Adolf Molling (1865-1921) is posing on the grass in front.

Therese Gottschalk with her daughter Elizabeth outdoors; Marienbad.

Verso: addressed to Herrn u. Frau Louis Gottschalk; Hannover; Elizabeth Gottschalk, born 1911

Reiss family portrait; (l-r) Olga, Herbert, Flora Lotte, Walter, Moritz and Kurt; Saaz, Czechoslovakia Portraits Family

Olga Reiss nee Kohn died 1950s; Herbert Reiss, 1905-circa 1980; Flora Lotte "Lola" Reiss, 1910-1995; Walter Reiss, 1908-1937; Moritz Reiss, 1876-1965; Kurt Reiss, 1906-1996

Studio portrait of Josef Reiss(?); Saaz, Czechosolvakia Portraits Men

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Portrait of Olga Reiss nee Kohn Portraits Women

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Portrait of Olga Reiss nee Kohn Portraits Women

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Portrait of Olga Reiss nee Kohn Portraits Women

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Studio portrait of Flora Lotte "Lola" Reiss; Saaz, Czechoslovakia Portraits Women

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Flora Lotte "Lola" Reiss walking in the street with her father Moritz; Karlovy Vary (Carlsbad) Portraits Family

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Flora Lotte "Lola" Reiss walking in the street with her non-Jewish boyfriend Walter; Karlovy Vary (Carlsbad) Portraits Family

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Ruth Augusta Beatrice Goldschmidt outside the Richmond Park Hotel; Karlsbad Portraits Women

Born 1923?

Ruth Augusta Beatrice Goldschmidt with her parents Paula Goldschmidt née Harmelin and Martin Goldschmidt, walking on the street outside the Richmond Park Hotel; Karlsbad Portraits Family

Paula Goldschmidt, née Harmelin, born 1880; Martin Goldschmidt, born circa 1879; Ruth Augusta Beatrice Goldschmidt, born 1923?

Jacob Judey-Barosin and his father Hermann Judey hiking with friends; Sächsische Schweiz Portraits Men

l-r: Martin Lipschitz, Sam Kohn, Hermann Judey, Willy Lipschitz, Georg Eliasberg and Jacob Judey-Barosin