(Table 1) Summary statistics of taxa in samples of ODP Hole 181-1123B

Planktonic foraminifera are used to identify late Pliocene-Quaternary near surface water masses on the northeastern flank of Chatham Rise by comparison with faunas in core-tops east of New Zealand. In an overview study, distance measures, ordinations, and discriminant analysis are applied to 32 faunas from Site 1123B to identify similar faunas among 35 core-tops between 35 and 61°S east of New Zealand. Many Site 1123B faunas in the 2.72 myr interval sampled compare with those in core-tops on the northern side of Chatham Rise from a similar latitude, and are identified as transitional zone assemblages now associated with the subtropical gyre. This result is consistent with studies of late Quaternary planktonic foraminifera from this region and suggests that, typically, the Subtropical Front was locked to Chatham Rise through glacial and interglacial periods, at least back to the late Pliocene. However, a fauna at ca. 1.17 Ma compares with subpolar assemblages in core-tops between 44 and 48°S and identifies cooler surface water. Expectedly, closer sampling may reveal additional periods when southern water moved over the northeastern flank of Chatham Rise. Although the dominance of Globorotalia inflata, a species typical of the southern margin of subtropical gyres, is a principal feature of Site 1123B faunas, in a minority it is replaced as the most abundant species by dextral populations of Neogloboquadrina pachyderma, particularly about the time of the middle Pleistocene transition. Close analogues of these variant transitional assemblages are not present in core-tops about Chatham Rise but sediment trap and coretop data from other regions suggest that they identify high fertility in the mixed layer associated with upwelling or mixing of water masses. The proportion of sinistrally coiled Neogloboquadrina pachyderma rises to ca. 0.6 between ca. 2.45 and 2.57 Ma, soon after the intensification of Northern Hemisphere glaciation. Although the coiling data indicate subantarctic near surface water, the species remains rare. As the faunas retain their transitional zone character, only minor entrainment of subantarctic water may have occurred.

Phospholipid fatty acid and quinone composition of sediments from ODP Leg 205 sites

Assessing the habitability of deep-sea sediments undergoing compaction, compression, and subduction at convergent margins adds to our understanding of the limits of the terrestrial biosphere. In this work, we report exploratory biomarker data on sediments obtained at Ocean Drilling Program (ODP) Sites 1253, 1254, and 1255 during drilling at the Costa Rica subduction trench and forearc sedimentary wedge. The samples selected for postcruise biomarker analyses were located within intervals of potentially enhanced fluid flow within the décollement and sedimentary wedge fault zones (Sites 1254 and 1255) and within basal carbonates at the reference site (Site 1253). The passage of fluids that are geochemically distinct from ambient interstitial water provides a disequilibrium setting that may enhance habitability. Biomarker data show low levels of microbial biomass in subseafloor sediments sampled at the Costa Rica convergent margin as deep as ~370 meters below seafloor.

Classical and Cosserat plasticity and viscoplasticity models for slow granular flow

We consider models for the rheology of dense, slowly deforming granular materials based of classical and Cosserat plasticity, and their viscoplastic extensions that account for small but finite particle inertia. We determine the scale for the viscosity by expanding the stress in a dimensionless parameter that is a measure of the particle inertia. We write the constitutive relations for classical and Cosserat plasticity in stress-explicit form. The viscoplastic extensions are made by adding a rate-dependent viscous stress to the plasticity stress. We apply the models to plane Couette flow, and show that the classical plasticity and viscoplasticity models have features that depart from experimental observations; the prediction of the Cosserat viscoplasticity model is qualitatively similar to that of Cosserat plasticity, but the viscosities modulate the thickness of the shear layer.

Localization of testis-variant histones in rat testis chromatin

Nucleosome core particles and oligonucleosomes were isolated by digesting rat testis nuclei with micrococcal nuclease to 20% acid-solubility, followed by fractionation of the digest on a Bio-Gel A-5m column. The core particles thus isolated were characterized on the basis of their DNA length of 151 +/- 5 base-pairs and sedimentation coefficient of 11.4S. Analysis of the acid-soluble proteins of the core particles indicated that histones TH2B and X2 are constituents of the core particles, in addition to the somatic histones H2A, H2B, H3 and H4. The acid-soluble proteins of the oligonucleosomes comprised all the histones, including both the somatic (H1, H2A, H2B, H3, H4 and X2) and the testis-specific ones (TH1 and TH2B). It was also observed that histones TH1 and H1 are absent from the core particles and were readily extracted from the chromatin by 0.6 M-NaCl, which indicated that both of them are bound to the linker DNA.

Fluorescent Fields: electric lighting and the rationalization of the modern corporate workplace

This study investigates the implications of the introduction of electric lighting systems, building technologies, and theories of worker efficiency on the deep spatial and environmental transformations that occurred within the corporate workplace during the twentieth century. Examining the shift from daylighting strategies to largely artificially lit workplace environments, this paper argues that electric lighting significantly contributed to the architectural rationalization of both office work and the modern office environment. Contesting the historical and critical marginalization of lighting within the discourse of the modern built environment, this study calls for a reassessment of the role of artificial lighting in the development of the modern corporate workplace. Keywords: daylighting, fluorescent lighting, rationalization, workplace design

Excitation energy transfer in covalently linked pheophorbied—porphyrin systems

Steady-state fluorescence, lifetime measurements and time-resolved absorption spectra of the covalently linked hetero dimers consisting of pheophorbide and porphyrin revealed rapid (1011–1012s−1) and efficient singlet—singlet excitation energy transfer from porphyrin unit to pheophorbide.

The orientational relaxation of bipolar active regions

In the mean, bipolar active regions are oriented nearly toroidally, according to Hale's polarity law, with a latitude-dependent tilt known as Joy's Law. The tilt angles of individual active regions deviate from this mean behavior and change over time. It has been found that on average the change is toward the mean angle at a rate characteristic of 4.37 days (Howard, 1996). We show that this orientational relaxation is consistent with the standard model of flux tube emergence from a deep dynamo layer. Under this scenario Joy's law results from the Coriolis effect on the rising flux tube (D'Silva and Choudhuri, 1993), and departures from it result from turbulent buffeting of the tubes (Longcope and Fisher, 1996). We show that relaxation toward Joy's angle occurs because the turbulent perturbations relax on shorter time scales than the perturbations from the Coriolis force. The turbulent perturbations relax more rapidly because they are localized to the topmost portion of the convection zone while the Coriolis perturbations are more widely distributed. If a fully-developed active region remains connected to the strong toroidal magnetic field at the base of the convection zone, its tilt will eventually disappear, leaving it aligned perfectly toroidally. On the other hand, if the flux becomes disconnected from the toroidal field the bipole will assume a tilt indicative of the location of disconnection. We compare models which are connected and disconnected from the toroidal field. Only those disconnected at points very deep in the convection zone a-re consistent with observed time scale of orientational relaxation.

Avaliação da morfologia testicular e dos parâmetros espermáticos em ratos espontaneamente hipertensos e tratados com enalapril

A hipertensão arterial sistêmica (HAS) é um problema de saúde pública, geralmente associada a outras doenças, como obesidade, diabetes, doença renal, aterosclerose, acidente vascular cerebral (AVC) e identificado como um dos fatores de risco mais prevalentes para o desenvolvimento de doenças cardiovasculares. Orgãos-alvo, como coração, rins, cérebro e olhos, são comumente afetados em pacientes hipertensos. No entanto, o dano testicular causado pela hipertensão não foi claramente definido. A hipertensão é um fator de risco bem estabelecido para a disfunção erétil, mas sua relação com o dano testicular e a fertilidade masculina não é claramente compreendida. Este estudo avalia a morfologia testicular e alguns parâmetros espermáticos de ratos espontaneamente hipertensos (SHR), virgem de tratamento e tratados com enalapril. Ratos SHR foram distribuídos em dois grupos, um grupo hipertenso (H), e um grupo tratado com enalapril (HE). Ratos Wistar-Kyoto (WKY) foram utilizados como controles. A pressão arterial sistólica foi medida semanalmente, até o final do experimento. A concentração de espermatozóides, motilidade e viabilidade foram determinadas em amostras coletadas da cauda do epidídimo. Métodos estereológicos foram usados para analisar objetivamente a morfologia testicular macroscopicamente e microscopicamente. Todos os dados foram analisados por ANOVA com pós-teste de Tukey, considerando p <0,05. Ao final do experimento a pressão arterial sistólica no grupo HE (153,9 mmHg 21,03 ) foi semelhante a dos animais pertencentes ao grupo WKY (153,4 24,41) e menor que a dos animais H (205,1 24,9). A concentração espermática do grupo H (1,31 x 107 sptz/ml 0,27) foi inferior à do grupo WKY (2,11 x 107 sptz/ml 0,34), entretanto o controle da pressão arterial com o enalapril melhorou este parâmetro e a concentração espermática do grupo HE (2,46 x 107 sptz/ml 0,54) foi semelhante a do WKY. A densidade volumétrica vascular também foi alterada no grupo de hipertensos, enquanto que os animais do grupo HE foram semelhantes aos controles. O epitélio seminífero dos animais HE apresentou a maior densidade volumétrica, indicando um possível efeito protetor indireto do enalapril na espermatogênese. Neste modelo animal, a HAS promoveu alterações morfológicas no testículo, com conseqüências sobre a produção de espermatozóides. O controle da pressão arterial com o enalapril protegeu o testículo destas alterações, restabelecendo a produção normal dos espermatozóides.

钆对费氏中华根瘤菌抑制效应的蛋白质组分析

运用双向凝胶电泳和MALDI-TOF质谱技术,分析了Gd3+对费氏中华根瘤菌USDA 205的抑制效应。结果表明,经1 mmol.L-1Gd3+处理12 h后,22个蛋白质表达量有显著变化,其中13个蛋白质表达量增加,9个蛋白质表达量下降。这些蛋白质可根据功能分为8类,包括转运蛋白、胁迫相关蛋白、代谢相关蛋白等。

快速凝固 Ti-Zr-Ni 合金的电化学贮氢性能

采用铜辊快速凝固方法制备了Ti45Zr30Ni25和Ti50Zr25Ni25合金,并对合金作为镍-氢二次电池负极的动力学和电化学性能进行了研究。结果表明,Ti45Zr30Ni25为非晶相合金,Ti50Zr25Ni25合金由准晶相和非晶相组成。两合金电极的最大放电容量分别为129和132mAh/g。在240mA/g电流密度下,高倍率放电性能(HRD)分别为62.7%和63.3%。合金电极的交换电流密度分别为205.1和375.6mA/g,氢在合金中的扩散系数分别为5.4×10-11和5.8×10-11cm2·s-1

A unusual pinnotherid zoea attributed to Afropinnotheres monodi Manning, 1993 (Decapoda: Brachyura: Pinnotheridea) from the Selvagens Islands (Eastern Atlantic Ocean)

A pinnotherid zoea taken in a plankton sample from the Selvagens Islands during the TFMCBM/SELVAGENS’2000 Cruise, organized by the Natural Sciences Museum of Tenerife (Canary Islands), differs from previously described zoeas of the family. The specimen has dorsal and lateral spines but no rostrum, a combination of characters not previously described from pinnotherid zoeas. The lateral spines originate behind the upper part of the eye, unlike all previously described Pinnotheridae zoeas where these spines, when present, originate near the ventrolateral margin of the carapace. The specimen is attributed to Afropinnotheres monodi, the only pinnotherid species known from the area with undescribed larvae.

Absolute Calibration of Atomic Density Measurements by Laser-Induced Fluorescence Spectroscopy with Two-Photon Excitation (TALIF)

The two-photon resonances of atomic hydrogen (? = 2 × 205.1 nm), atomic nitrogen (? = 2 × 206.6 nm) and atomic oxygen (? = 2 × 225.6 nm) are investigated together with two selected transitions in krypton (? = 2×204.2 nm) and xenon (? = 2×225.5 nm). The natural lifetimes of the excited states, quenching coefficients for the most important collisions partners, and the relevant ratios of the two-photon excitation cross sections are measured. These data can be applied to provide a calibration for two-photon laser-induced fluorescence measurements based on comparisons with spectrally neighbouring noble gas resonances.