ANODIC-OXIDATION OF HYDRAZINE ON GLASSY-CARBON ELECTRODES IN ACETONITRILE

The anodic oxidation kinetics of hydrazine on glassy carbon electrodes in acetonitrile were examined by cyclic voltammetry, a rotating ring-disc electrode technique and chronoamperometry. The experimental results of the rotating ring-disc electrode prove that hydrazine is oxidized to HN=NH, which cannot be oxidized further in acetonitrile. Hydrazine molecules are adsorbed on the electrode surface. One-third of the adsorbed hydrazine molecules are oxidized to HN=NH and the other two thirds act as proton acceptors. A possible mechanism of hydrazine oxidation is proposed.

Mossèn Bartomeu Oliver i Amengual. 'Mosén Bartomeu Oliver i Amengual'.

Se trata de una aproximación a la figura y personalidad de Bartomeu Oliver i Amengual (Sencelles, 1903-1993) y un intento de profundizar en su condición de maestro, cura y agricultor. Además de ser un hombre activo e investigador de su realidad más cercana, su diaria tarea docente en las escuelas de Algaida y Sencelles se caracteriza por un pensamiento pedagógico moderno cargado de interés, curiosidad y diálogo. Sacando provecho de su entorno más cercano, desarrolló planteamientos pedagógicos de activismo, experimentación y contacto directo con la realidad en diversas áreas de conocimiento, como geografía, ciencias naturales, agricultura, matemáticas y trabajos manuales, y puso en práctica los modernos postulados de la evaluación como diagnóstico y proceso. Llegó a ser director de la Escuela Graduada de Sencelles, donde estuvo hasta su jubilación en 1965, y da nombre a uno de los premios 31 de Diciembre de la asociación nacionalista Obra Cultural Balear. El trabajo analiza su perfil personal, su pensamiento pedagógico y la actuación docente desarrollada, y su opinión sobre la cultura y lengua de las Islas.

Acceso de los hogares a los principales servicios públicos y sociales y percepciones de calidad sobre estos servicios

Se presenta los principales resultados de la Encuesta de Calidad de Vida 2003 sobre los servicios públicos domiciliarios y los servicios sociales en Colombia, el análisis se hace comparativo con el año 1993 y 1997 tanto a nivel geográfico como a nivel socioeconómico. Se encuentra que a pesar del decremento en el ingreso que sufrieron los hogares, la calidad de vida de estos no ha decrecido. El acceso a los servicios domiciliarios ha mejorado con algunas brechas entre regiones. En educación han disminuido las tasas de analfabetismo junto con incrementos en la cobertura de la educación primaria y secundaria, sobre todo en lo ingresos bajo y medios. La matrícula superior continúa su baja y la oficial presenta una mayor participación. En materia de salud, el régimen subsidiado se convierte en un importante mecanismo anticíclico.

Genetic characterization of tick-borne flaviviruses: new insights into evolution, pathogenetic determinants and taxonomy

Here, we analyze the complete coding sequences of all recognized tick-borne flavivirus species, including Gadgets Gully, Royal Farm and Karshi virus, seabird-associated flaviviruses, Kadam virus and previously uncharacterized isolates of Kyasanur Forest disease virus and Omsk hemorrhagic fever virus. Significant taxonomic improvements are proposed, e.g. the identification of three major groups (mammalian, seabird and Kadam tick-borne flavivirus groups), the creation of a new species (Karshi virus) and the assignment of Tick-borne encephalitis and Louping ill viruses to a unique species (Tick-borne encephalitis virus) including four viral types (i.e. Western Tick-borne encephalitis virus, Eastern Tick-borne encephalitis virus, Turkish sheep Tick-borne encephalitis virus and Louping ill Tick-borne encephalitis virus). The analyses also suggest a complex relationship between viruses infecting birds and those infecting mammals. Ticks that feed on both categories of vertebrates may constitute the evolutionary bridge between the three distinct identified lineages.

Acid dissociation of 2,2 '-dipyridylamine in non-aqueous medium when chelated to some Ru(II)N-4 cores

[Ru(2,2'-bipyridine)(2)(Hdpa)](BF4)(2) center dot 2H(2)O (1), [Ru(1,10-phenanthroline)(2)(Hdpa)] (PF6)(2) center dot CH2Cl2 (2) and [Ru(4,4,4',4'-tetramethyl-2,2'- bisoxazoline)(2)(Hdpa)] (PF6)(2) (3) are synthesized where Hdpa is 2,2'-dipyridylamine. The X-ray crystal structures of 1 and 2 have been determined. Hdpa in 1 and 2 is found to bind the metal via the two pyridyl N ends. Comparing the NMR spectra in DMSO-d(6), it is concluded that 3 has a similar structure. The pK(a) values (for the dissociation of the NH proton in Hdpa) of free Hdpa and its complexes are determined in acetonitrile by exploiting molar conductance. These correlate linearly with the chemical shift of the NH proton in the respective entities. (C) 2007 Elsevier B.V. All rights reserved.

Influence of counter anions on the structures and magnetic properties of trinuclear Cu(II) complexes containing a mu(3)-OH core and Schiff base ligands

Four trinuclear Cu(II) complexes, [(CuL1)(3)(mu(3)-OH)](NO3)(2) (1), [(CuL2)(3)(mu(3)-OH)](I)(2)center dot H2O (2), [(CuL3)(3)(mu(3)-OH)](I)(2) (3) and [(CuL1)(3)(mu(3)-OH)][(CuI3)-I-1] (4), where HL1 (8-amino-4-methyl-5-azaoct-3-en-2-one), HL2 [7-amino-4-methyl-5-azaoct-3-en-2-one] and HL3 [7-amino-4-methyl-5-azahept-3-en-2- one] are the three tridentate Schiff bases, have been synthesized and structurally characterized by X-ray crystallography. All four complexes contain a partial cubane core, [(CuL)(3)(mu(3)-OH)](2+) in which the three [CuL] subunits are interconnected through two types of oxygen bridges afforded by the oxygen atoms of the ligands and the central OH- group. The copper(II) ions are in a distorted square-pyramidal environment. The equatorial plane consists of the bridging oxygen of the central OH- group together with three atoms (N, N, O) from the Schiff base. The oxygen atom of the Schiff base also coordinates to the axial position of Cu(II) of another subunit to form the cyclic trimer. Magnetic susceptibilities have been determined for these complexes over the temperature range of 2-300 K. The isotropic Hamiltonian, H = -J(12)S(1)S(2) - J(13)S(1)S(3) - J(23)S(2)S(3) has been used to interpret the magnetic data. The best fit parameters obtained are: J = - 54.98 cm(-1) g = 2.24 for 1; J = - 56.66 cm(-1), g = 2.19 for 2; J = -44.39 cm(-1), g = 2.16 for 3; J = - 89.92 cm(-1), g = 2.25 for 4. The EPR data at low temperature indicate that the phenomenon of spin frustration occurs for complexes 1-3. (c) 2007 Elsevier B.V. All rights reserved.

Estimativas das exigências de lisina de frangos de corte pelos métodos dose resposta e fatorial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Eigentlicher Abriß der Edlen, Schönen Vestung Neytra : im Königreich Ungarn, welche mit aller Untreu und Hinterlist dem Türcken, im Monath Octobri dieses 1663. Jahrs, ohne Gegenwehr ist eingeraumt worden

Bibliogr. Nachweis: Harms II, 361