Argon, uranium, thorium and lead composition and ages of ODP Leg 180 sites

During Ocean Drilling Program (ODP) Leg 180, 11 sites were drilled in the vicinity of the Moresby Seamount to study processes associated with the transition from continental rifting to seafloor spreading in the Woodlark Basin. This paper presents thermochronologic (40Ar/39Ar, 238U/206Pb, and fission track) results from igneous rocks recovered during ODP Leg 180 that help constrain the latest Cretaceous to present-day tectonic development of the Woodlark Basin. Igneous rocks recovered (primarily from Sites 1109, 1114, 1117, and 1118) consist of predominantly diabase and metadiabase, with minor basalt and gabbro. Zircon ion microprobe analyses gave a 238U/206Pb age of 66.4 ± 1.5 Ma, interpreted to date crystallization of the diabase. 40Ar/39Ar plagioclase apparent ages vary considerably according to the degree to which the diabase was altered subsequent to crystallization. The least altered sample (from Site 1109) yielded a plagioclase isochron age of 58.9 ± 5.8 Ma, interpreted to represent cooling following intrusion. The most altered sample (from Site 1117) yielded an isochron age of 31.0 ± 0.9 Ma, interpreted to represent a maximum age for the timing of subsequent hydrothermal alteration. The diabase has not been thermally affected by Miocene-Pliocene rift-related events, supporting our inference that these rocks have remained at shallow and cool levels in the crust (i.e., upper plate) since they were partially reset as a result of middle Oligocene hydrothermal alteration. These results suggest that crustal extension in the vicinity of the Moresby Seamount, immediately west of the active seafloor spreading tip, is being accommodated by normal faulting within latest Cretaceous to early Paleocene oceanic crust. Felsic clasts provide additional evidence for middle Miocene and Pliocene magmatic events in the region. Two rhyolitic clasts (from Sites 1110 and 1111) gave zircon 238U/206Pb ages of 15.7 ± 0.4 Ma and provide evidence for Miocene volcanism in the region. 40Ar/39Ar total fusion ages on single grains of K-feldspar from these clasts yielded younger apparent ages of 12.5 ± 0.2 and 14.4 ± 0.6 Ma due to variable sericitization of K-feldspar phenocrysts. 238U/206Pb zircon, 40Ar/39Ar K-feldspar and biotite total fusion, and apatite fission track analysis of a microgranite clast (from Site 1108) provide evidence for the existence of a rapidly cooled 3.0 to 1.8 Ma granitic protolith. The clast may have been transported longitudinally from the west (e.g., from the D'Entrecasteaux Islands). Alternatively, it may have been derived from a more proximal, but presently unknown, source in the vicinity of the Moresby Seamount.

The Quantum Mitochondrion and Optimal Health

A sufficiently complex set of molecules, if subject to perturbation, will self-organise and show emergent behaviour. If such a system can take on information it will become subject to natural selection. This could explain how self-replicating molecules evolved into life and how intelligence arose. A pivotal step in this evolutionary process was of course the emergence of the eukaryote and the advent of the mitochondrion, which both enhanced energy production per cell and increased the ability to process, store and utilise information. Recent research suggest that from its inception life embraced quantum effects such as “tunnelling” and “coherence” while competition and stressful conditions provided a constant driver for natural selection. We believe that the biphasic adaptive response to stress described by hormesis – a process that captures information to enable adaptability, is central to this whole process. Critically, hormesis could improve mitochondrial quantum efficiency, improving the ATP/ROS ratio, while inflammation, which is tightly associated with the aging process, might do the opposite. This all suggests that to achieve optimal health and healthy ageing, one has to sufficiently stress the system to ensure peak mitochondrial function, which itself could reflect selection of optimum efficiency at the quantum level.

Estrategias museográficas actuales relacionadas con la museología crítica

Este artículo evita la mera disquisición teórica sobre museología crítica, sugiriendo en lugar de ello algunas pistas para calibrar su influencia en la praxis museal. Ante todo, se propone como emblemático de la museografía crítica el uso de interrogaciones en lugar de discursos asertivos; en segundo lugar, la sustitución de la impersonal autoridad institucional por prácticas participativas e interpretaciones compartidas, para dar idea de una variedad de opiniones, incluyendo las de gentes ajenas al museo; finalmente, es un rasgo distintivo el énfasis en la naturaleza subjetiva de los montajes museísticos, mostrando sus cambios a través de la historia, y señalando la autoría personal de las presentaciones y textos en el museo.

A PROBLEMÁTICA DO RECONHECIMENTO E DA MENSURAÇÃO DOS ATIVOS FIXOS TANGÍVEIS: ESTUDO COMPARATIVO DO SNC E DO SNC-AP

Este trabalho tem por objetivos analisar o definido no SNC e no SNC-AP, quanto ao reconhecimento e mensuração dos ativos fixos tangíveis (AFT). Este estudo permite concluir, quanto ao reconhecimento dos AFT, que o SNC-AP aproxima-se do SNC, com algumas particularidades específicas do âmbito público, como o facto de um elemento poder ser reconhecido como ativo mesmo que não produza rendimentos, desde que possua potencial de serviços. Por outro lado, no que respeita à mensuração, o SNC-AP segue de perto, com as devidas adaptações, os normativos internacionais e também o SNC, mas na mensuração subsequente dos AFT, apenas apresenta a revalorização como alternativa ao custo.

La explicación del rendimiento en los cursos introductorios de economía. ¿Cuánto influye el profesor?: un estudio en la Universidad del Pacífico

La presente investigación explica las calificaciones finales de los estudiantes del curso de Economía de la Universidad del Pacífico con el objetivo de comparar el impacto de las experiencias y los conocimientos previos del estudiante frente al desempeño de sus profesores. Para ello, se aplicaron modelos de regresión censurados conocidos como Tobit model, los cuales corrigieron los problemas de censura de la variable dependiente. Los modelos desarrollados resultaron libres de sesgo de selección muestral, y sus procesos de estimación consideraron variables académicas, psicológicas, sociofamiliares, de identificación y pedagógicas. A través de ellos, un conjunto de factores asociados a las experiencias y los conocimientos previos del estudiante resultó ser el de mayor impacto sobre el rendimiento académico. Así, dos variables académicas —la calificación escolar promedio en matemáticas alcanzada durante los tres últimos años de educación secundaria y la asistencia a un colegio privado—, estuvieron entre las más importantes para explicar las calificaciones finales de Economía I. Tres factores académicos adicionales también contribuyeron a elevar las calificaciones: haber estudiado en un colegio que no sea preuniversitario, la procedencia de escuelas que diferencian por sexo (no mixtas) y haber sido expuesto a contenidos más amplios de economía durante la etapa escolar. Asimismo, tres docentes impactaron de modo positivo, pero su impacto fue mucho menor que el de los factores académicos. Es decir, el rendimiento previo y el currículo escolar llegan a importar mucho más que el desempeño didáctico del docente para el éxito académico en las asignaturas introductorias de economía. Finalmente, debido a que no se encontró que los docentes mejor evaluados por los estudiantes impactaban sobre el rendimiento de sus alumnos, se evidencia que es importante revisar los sistemas de evaluación docente, para evitar que estos se conviertan en un instrumento mediante el cual los estudiantes penalicen a los profesores exigentes y que, por el contrario, contribuyan a retroalimentar al docente y a mejorar su desempeño.

Antígona: nome de código: a peça em um ato de Mário Sacramento

Sob a influência da Antígona sofocliana, Mário de Sacramento escreveu uma peça homónima publicada, isoladamente, em 1959, no vol. XIX, nº 186 da “Revista Vértice”, e incluída, no ano seguinte, na tetralogia intitulada Teatro Anatómico. Nesta peça em um ato, a tragédia homónima de Sófocles configura-se um recurso metateatral de carácter crítico-reflexivo, em que o diálogo intertextual com o ancestral texto trágico promove uma leitura dramática do destino infortunado dos sobreviventes de uma família francesa, vítima da ocupação alemão, na Segunda Guerra Mundial, que, como os últimos Labdácidas, confrontam o sofrimento de situações-limite, ditadas por conflitos insolúveis da condição humana. Neste «ensaio dramático de Mário de Sacramento, a protagonista é uma mulher francesa, Ivonne, que no tempo do Maquis, escolhe, como nome de código, “Antígona”. Pretende-se, neste estudo, apresentar uma análise da influência exercida pela Antígona sofocliana neste «ensaio dramático», ao nível da caracterização das dramatis personae e do desenvolvimento da ação, que se sustenta numa reflexão crítica sobre as motivações da filha de Édipo e o sentido trágico das suas ações.

Solar Energy Conversion by Nanostructured TiO2

Research in solar energy conversion and the associated photoactive materials has attracted continuous interest. Due to its proper electronic band structure, high quantum efficiency, and photonic and chemical innerness, TiO2 has been demonstrated as a versatile oxide semiconductor capable of efficiently utilizing sunlight to produce electrical and chemical energy. Its outstanding physicochemical performances have led to an array of advanced photocatalytic and photoelectrochemical applications including environmental photocatalysis, dye/semiconductor-sensitized solar cell, and solar fuel productions.

Preparation, Characterization, and Photocatalytic Applications of MWCNTs/TiO2 Composite

The multiwall carbon nanotubes (MWCNTs)/titanium dioxide (P25) composite in different ratios was prepared using simple evaporation and drying process. The composite was characterized by Raman spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of this composite was investigated using degradation of the Bismarck brown R dye (BBR). An optimal MWCNTs/TiO2 ratio of 0.5% (w/w) was found to achieve the maximum rate of BBR degradation. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO2. The enhancement in photocatalytic activity performance of the MWCNTs/P25 composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNTs act as a dispersing support to control the morphology of TiO2 particles in the MWCNTs/TiO2 composite.

Photocatalytic Degradation of Anthracene in Closed System Reactor

Polycyclic aromatic hydrocarbons (PAHs) represent a large class of persistent organic pollutants in an environment of special concern because they have carcinogenic and mutagenic activity. In this paper, we focus on and discuss the effect of different parameters, for instance, initial concentration of Anthracene, temperature, and light intensity, on the degradation rate. These parameters were adjusted at pH 6.8 in the presence of the semiconductor materials (TiO2) as photocatalysts overUVlight. The main product of Anthracene photodegradation is 9,10-Anthraquinone which isidentified and compared with the standard compound by GC-MS. Our results indicate that the optimum conditions for the best rate of degradation are 25 ppm concentration of Anthracene, regulating the reaction vessel at 308.15 K and 2.5 mW/cm(2) of light intensity at 17 5mg/100 mL of titanium dioxide (P25).

Role of Platinum Deposited on TiO2 in Photocatalytic Methanol Oxidation and Dehydrogenation Reactions

Titania modified nanoparticles have been prepared by the photodeposition method employing platinum particles on the commercially available titanium dioxide (Hombikat UV 100). The properties of the prepared photocatalysts were investigated by means of the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-visible diffuse spectrophotometry (UV-Vis). XRD was employed to determine the crystallographic phase and particle size of both bare and platinised titanium dioxide. The results indicated that the particle size was decreased with the increasing of platinum loading. AFM analysis showed that one particle consists of about 9 to 11 crystals. UV-vis absorbance analysis showed that the absorption edge shifted to longer wavelength for 0.5% Pt loading compared with bare titanium dioxide. The photocatalytic activity of pure and Pt-loaded TiO2 was investigated employing the photocatalytic oxidation and dehydrogenation of methanol. The results of the photocatalytic activity indicate that the platinized titanium dioxide samples are always more active than the corresponding bare TiO2 for both methanol oxidation and dehydrogenation processes. The loading with various platinum amounts resulted in a significant improvement of the photocatalytic activity of TiO2. This beneficial effect was attributed to an increased separation of the photogenerated electron-hole charge carriers.

Durability of Ag-TiO(2) Photocatalysts Assessed for the Degradation of Dichloroacetic Acid

The stability of Ag-TiO(2) photocatalysts was examined for the photocatalytic degradation of dichloroacetic acid (DCA) as a function of the recycling times. The photocatalytic activity was investigated by measuring the rate of H(+) ions released during the photodegradation of DCA and confirmed by measuring the total organic carbon removal. The photodegradation reactions were studied at pH 3 and pH 10 for a series of Ag-TiO(2) photocatalysts as different with Ag loadings. All the Ag-TiO(2) and bare TiO(2) photocatalysts showed a decrease in photocatalytic activity on recycling for the DCA photodegradation reaction. The decrease in activity can be attributed to poisoning of active sites by Cl(-) anions formed during the photocatalytic DCA degradation. The photocatalytic activity was, however, easily recovered by a simple washing technique. The reversibility of the poisoning is taken as evidence to support the idea that the recycling of Ag-P25 TiO(2) photocatalysts does not have a permanent negative effect on their photocatalytic performance for the degradation of DCA. The choice of the preparation procedure for the Ag-TiO2 photocatalysts is shown to be of significant importance for the observed changes in the photocatalytic activity of the Ag-TiO2 particles. Copyright (C) 2008 Victor M. Menendez-Flores et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Annaes da Camara dos Deputados. Tomo XV [1920]

Anais da Câmara dos Deputados, 1920.

Cirrhosis Diagnosis and Liver Fibrosis Staging: Transient Elastometry Versus Cirrhosis Blood Test.

International audience

Characterization of the Interactions between Endocrine Disruptors and Aquatic Humic Substances from Tropical Rivers

Interactions between two endocrine disruptors (ED) and aquatic humic substances (AHS) from tropical rivers were studied using an ultrafiltration system equipped with a 1 kDa cut-off cellulose membrane to separate free ED from the fraction bound in the AHS. Quantification of 17 alpha-ethynylestradiol and bisphenol A was performed using gas chromatography-mass spectrometry (GC-MS). The times required for establishment of equilibrium between the AHS and the ED were ca. 30 min, and complexation capacities for 17 alpha-ethynylestradiol and bisphenol A were 18.53 and 2.07 mg g(-1) TOC, respectively. The greater interaction of AHS with 17 alpha-ethynylestradiol, compared to bisphenol A, was due to the presence of hydrogen in the structure of 17 alpha-ethynylestradiol, which could interact with ionized oxygenated groups of the AHS. The results indicate that AHS can strongly influence the transport and reactivity of endocrine disruptors in aquatic systems.