Polarity chron boundaries and interval sedimentation rates of ODP Leg 162 sites

Magnetic polarity stratigraphies for Sites 980-984 are based on shipboard measurements from the pass-through magnetometer after alternating field (AF) demagnetization at a peak field of 25 mT and shore-based stepwise AF demagnetization of discrete samples. The characteristic magnetization component was determined after AF demagnetization removed the steep downward drill-string-related magnetic overprint. Peak AF fields in the 20-30 mT range were required to resolve the component, carried by magnetite, that was used to produce unambiguous Pliocene-Pleistocene magnetic stratigraphies at all five sites. At Sites 980 and 983, magnetic stratigraphies were resolved to the base of the recovered advanced hydraulic piston corer (APC) section, which lies in the Matuyama Chron (1r.2r) and Olduvai Subchron (2n), respectively. At Sites 981 and 982, magnetization intensities decrease sharply in the normal polarity zone corresponding to the Gauss Chron (2An), and magnetic stratigraphies below this level could not be resolved. At Site 984, the resolution of magnetic stratigraphy was curtailed at ~250 meters below seafloor (Olduvai Subchron) by core deformation at the base of the APC section and in the underlying extended core barrel section. As the magnetic stratigraphies at all four sites are unequivocal, polarity chron interpretations can be made without aid from the biostratigraphy. Mean sedimentation rates within polarity chrons have been calculated and Pliocene-Pleistocene biomagnetostratigraphic correlations tested.

Benthic foraminifera groups of ODP Site 162-982

The pulsed decline and eventual extinction of 51 species of elongate, cylindrical deep-sea benthic foraminifera (Stilostomellidae, Pleurostomellidae, and some Nodosariidae) occurred at intermediate water depths (1145-2168 m, Sites 980 and 982) in the northern North Atlantic during the mid-Pleistocene transition (MPT, 1.2-0.6 Ma). In the early Pleistocene, prior to their disappearance, these species comprised up to 20% of the total abundance of the benthic foraminiferal assemblage at 2168 m, but up to only 2% at 1145 m. The MPT extinction of 51 species represents ?20% of the total benthic foraminiferal diversity at bathyal depths in the North Atlantic (excluding the myriad of small unilocular forms). The extinction rate during the MPT was approximately 10 species per 0.1 myr, being one or two orders of magnitude greater than normal background turnover rates of deep-sea benthic foraminifera. Comparison of the precise timings of declines and disappearances (= highest occurrences) of each species shows that they were often diachronous between the two depths. The last of these species to disappear in the North Atlantic was Pleurostomella alternans at ~0.679 and ~0.694 Ma in Sites 980 and 982, respectively, which is in good agreement with the previously documented global "Stilostomella extinction" datum within the period 0.7-0.58 Ma. Comparison with similar studies in intermediate depth waters in the Southwest Pacific Gateway indicates that ~61% of the extinct species were common to both regions, and that although the pattern of pulsed decline was similar, the precise order and timing of the extinction of individual species were mostly different on opposite sides of the world. Previous studies have indicated that this extinct group of elongate, cylindrical foraminifera lived infaunally and had their greatest abundances in poorly ventilated, lower oxygen environments. This is supported by our study where there is a strong positive correlation (r = ~+ 0.8) between the flux of the extinction group and low-oxygen/high organic input species (such as Uvigerina, Bulimina and Bolivina) during the MPT, suggesting a close relationship with lower oxygen levels and high food supply to the sea floor. The absolute abundance, flux, and number of the extinction group of species show a progressive withdrawal pattern with major decreases occurring in cold periods with high d13C values. This might be related to increasing chemical ventilation of glacial intermediate water.

Sapientia, 1986, Vol. XLI, nº 162 (número completo)

Contenido: La causa IV : necesidad de la primera causa o acto de Dios / Octavio N. Derisi -- La cuestión del "paso" indebido de las proposiciones especulativas a las prácticas y la respuesta de Tomás de Aquino / Carlos I. Massini -- Significado del pensamiento de Michele Federico Sciacca para el hombre de hoy / Alberto Caturelli -- La sociedad nacional y la sociedad internacional para el análisis de la doctrina social de la Iglesia / Pedro E. Baquero Lazcano -- Notas y comentarios -- Bibliografía

Diário da Constituinte [gravação de vídeo] : [programa n. 162]

Foi testada a porta de detector de metais posicionada na entrada das galerias do Plenário. É um equipamento de segurança com cem por cento de tecnologia nacional. O Deputado Jorge Arbage (PDS-PA) informa que a porta estava dentro do programa estabelecido para as normas de segurança da Assembleia Nacional Constituinte (ANC). O Deputado Mauro Miranda (PMDB-GO) defende emendas em favor da autonomia dos municípios. O Deputado Amaury Muller (PDT-RS) declara que o Poder Executivo não tem respondido os requerimentos de informações do Poder Legislativo e considera isso um desrespeito à soberania da Constituinte. Na sessão O Povo Pergunta, cidadã quer saber o que muda no direito de expressão. O Deputado Ruy Nedel (PMDB-RS) responde que o "direito de dizer" já mudou com a queda da ditadura e cita as figuras da Inconstitucionalidade por Omissão e do Defensor do Povo como formas de mudar o direito de fazer a Constituição ser cumprida. Jair Meneguelli, Presidente da Central Única dos Trabalhadores (CUT), conclama a população a assinar as emendas populares.

Diário da Constituinte [gravação de vídeo] : [programa n. 162 A]

Opinião de cidadãos sobre a proposta de aprovar a nova Constituição através de plebiscito. Dois projetos de resolução, apresentados pelos Deputados Brandão Monteiro (PDT-RJ) e Virgílio Guimarães (PT-MG). estabelecem que, após 90 dias da promulgação da nova Carta, ela seja aprovada por um plebiscito. O Deputado Virgílio Guimarães (PT-MG) considera que a palavra final cabe ao eleitor. O Deputado Alceni Guerra (PFL-PR) quer plebiscitos parciais, por temas. Em debate promovido pelo 1º Secretário da Assembleia Nacional Constituinte Marcelo Cordeiro, líderes partidários fazem um balanço do projeto de Constituição. O Deputado Brandão Monteiro (PDT-RJ) rejeita a ideia de chamar de "monstrengo" a nova Constituição, mas diz que ela precisa de ajustes. O Deputado Luiz Henrique (PMDB-SC) declara ser fundamental o entendimento dos partidos nas questões polêmicas, para que se faça uma Constituição moderna. José Carlos Coutinho (PL-RJ) critica o aproveitamento, no projeto, do texto do substitutivo recusado na Comissão de Educação da Assembleia Nacional Constituinte (ANC). O Senador Carlos Chiarelli (PFL-RS) declara que a negociação é urgente e indispensável. O Deputado Bonifácio de Andrada (PDS-MG) considera que as negociações permitirão o consenso na votação no Plenário. A Deputada Irma Passoni (PT-SP) declara que cada partido deve afirmar seus princípios, mas também trabalhar para uma negociação possível no sentido de alcançar as necessidades atuais da nação brasileira. Cidadãos assinam as emendas populares nos pontos mais movimentados das cidades. As principais emendas populares que estão circulando pelo país tratam dos seguintes temas: direito dos trabalhadores; direitos da mulher; conselho de comunicação; educação.

Characteristics of 980/1550 nm WDM coupler based on planar curved waveguides

A wavelength division multiplexer (WDM) for 980/1550 nm based on planar curved waveguide coupler (CWC) is proposed. Compared with conventional parallel straight waveguide coupler (SWC), this structure has more flexibility with two variable parameters of bending radius R and minimum edge-to-edge spacing do, which are the two main parameters for the splitting ratio of coupler and decrease the complexity of device design and fabrication. Based on coupled mode theory (CMT) and waveguide theory, R and do of the WDM CWC are designed to be R = 13.28 m and d(0) = 4.39 mu m. The contrast ratio (CR) and insertion loss (IL) for 980 and 1550 nm are CR1 = 24.62 dB, CR2 = 24.56 dB and IL1 = 0.014 dB, IL2 = 0.015 dB, respectively. The 3D beam propagation method (BPM) is used to verify the validity of the design result. The influence of R and d(0) variations on the device performance is analyzed. For CR > 20 dB, the variation ranges of R and d(0) should be within -0.10 to +0.44 m and -0.05 to + 0.02 mu m, respectively. (c) 2006 Elsevier GmbH. All rights reserved.

980 nm 抽运下Yb-Tm-Ho 三掺氟磷酸盐玻璃的2 μm 荧光性质

The thermal stability, 2 μm fluorescence properties and energy transfer mechanism in Ho³⁺ doped fluorophosphate glass sensitized by Yb³⁺ and Tm³⁺ were investigated. The characteristic temperatures, absorption spectrum and fluorescence spectrum of the glass sample were measured. ΔT calculated from the characteristic temperatures shows that the thermal stability of fluorophosphate glass is better than fluoride glass. According to the absorption spectrum, several spectroscopic parameters of the glass sample, such as Judd-Ofelt parameters and spontaneous transition probability were calculated and compared with other glass hosts. The largest spontaneous transition probability for Ho³⁺:⁵ I7&rarr⁵I8 transition in fluorophosphate glass which is 78.48 s^-1 indicates that fluorophosphate glass is an appropriate base glass to achieve 2 m fluorescence. From the fluorescence spectrum of the glass sample, the extremely strong 2.0 μm fluorescence intensity is observed, which is higher than the intensity of 1.8 μm fluorescence, showing that Ho³⁺ ions sensitized by Yb³⁺ and Tm³⁺ is efficient. Meanwhile, the absorption sections and emission sections of Yb³⁺, Tm³⁺ and Ho³⁺ were calculated and the pumping scheme and energy transfer mechanism among Yb³⁺, Tm³⁺ and Ho³⁺ are discussed. The study indicates that Yb-Tm-Ho tri-doped fluorophosphate glass is a significant sensitization glass system under 980 nm excitation for 2 μm applications.

High power 980 nm Al-free strained quantum-well lasers for erbium-doped fiber amplifiers

In this paper, we reported on the fabrication of 980 nm InGaAs/InGaAsP strained quantum-well (QW) lasers with broad waveguide. The laser structure was grown by low-pressure metalorganic chemical vapor deposition on a n(+)- GaAs substrate. For 3 mu m stripe ridge waveguide lasers, the threshold current is 30 mA and the maximum output power and the output power operating in fundamental mode are 350 mW and 200 mW, respectively. The output power from the single mode fiber is up to 100 mW, the coupling efficiency is 50%. We also fabricated 100 mu m broad stripe coated lasers with cavity length of 800 mu m, a threshold current density of 170 A/cm(2), a high slope efficiency of 1.03 W/A and a far-field pattern of 40 x 6 degrees are obtained. The maximum output power of 3.5 W is also obtained for 100 mu m wide coated lasers. (C) 2000 Elsevier Science B.V. All rights reserved.