3,178 research outputs found

    Radial deformation of the earth by oceanic tidal loading

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    A high-degree spherical harmonic series is used to compute the radial deformation of the Earth by oceanic tidal loading. By exploiting fast numerical transforms, this approach is found to be much more efficient, but no less accurate, than the traditional Green's function approach. The method is used to derive an atlas of load tide maps for 10 constitutents of the NSWC ocean tide model

    In situ chemichromic studies of interactions between a lutetium bis-octaalkyl-substituted phthalocyanine and selected biological cofactors

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Royal Society.Spin-coated films, approximately 100 nm thick, of a newly synthesized bis[octakis(octyl)phthalocyaninato] lutetium(III) complex on ultrasonically cleaned glass substrates exhibit pronounced chemichromic behaviour with potential application in healthcare. In situ kinetic optical absorption spectroscopic measurements show that the phthalocyanine Q-band is red shifted by 60 nm upon oxidation arising from exposure to bromine vapour. Recovery to the original state is achieved by the treatment of the oxidized films with nicotinamide adenine dinucleotide and l-ascorbic acid (vitamin C) in an aqueous solution containing 1.5 M lithium perchlorate. The neutralization process is found to be governed by first-order kinetics. The linear increase of the reduction rate with increasing concentration of cofactors provides a basis for calibration of analyte concentrations ranging from 3.5 mM down to 0.03 mM.Air Force Office of Scientific Research, Air Force Material Command, USAF and the Leverhulme Trust

    The circumstellar environment of HD50138 revealed by VLTI/AMBER at high angular resolution

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    HD50138 is a Herbig B[e] star with a circumstellar disc detected at IR and mm wavelength. Its brightness makes it a good candidate for NIR interferometry observations. We aim to resolve, spatially and spectrally, the continuum and hydrogen emission lines in the 2.12-2.47 micron region, to shed light on the immediate circumstellar environment of the star. VLTI/AMBER K-band observations provide spectra, visibilities, differential phases, and closure phases along three long baselines for the continuum, and HI emission in Brγ\gamma and five high-n Pfund lines. By computing the pure-line visibilities, we derive the angular size of the different line-emitting regions. A simple LTE model was created to constrain the physical conditions of HI emitting region. The continuum region cannot be reproduced by a geometrical 2D elongated Gaussian fitting model. We estimate the size of the region to be 1 au. We find the Brγ\gamma and Pfund lines come from a more compact region of size 0.4 au. The Brγ\gamma line exhibits an S-shaped differential phase, indicative of rotation. The continuum and Brγ\gamma line closure phase show offsets of \sim-25±\pm5 o^o and 20±\pm10o^o, respectively. This is evidence of an asymmetry in their origin, but with opposing directions. We find that we cannot converge on constraints for the HI physical parameters without a more detailed model. Our analysis reveals that HD50138 hosts a complex circumstellar environment. Its continuum emission cannot be reproduced by a simple disc brightness distribution. Similarly, several components must be evoked to reproduce the interferometric observables within the Brγ\gamma, line. Combining the spectroscopic and interferometric data of the Brγ\gamma and Pfund lines favours an origin in a wind region with a large opening angle. Finally, our results point to an evolved source.Comment: accepted for publication in A&

    Oceanic tide maps and spherical harmonic coefficients from Geosat altimetry

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    Maps and tables for the global ocean tides, 69 degree N to 68 degree S, derived from two years of Geosat altimetry are presented. Global maps of local and Greenwich admittance of the (altimetric) ocean tide, and maps of amplitude and Greenwich phase lag of the ocean tide are shown for M(sub 2), S(sub 2), N(sub 2), O(sub 1), and K(sub 1). Larger scale maps of amplitude and phases are also shown for regional areas of special interest. Spherical harmonic coefficients of the ocean tide through degree and order 8 are tabulated for the six major constituents

    Opinion dynamics model with domain size dependent dynamics: novel features and new universality class

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    A model for opinion dynamics (Model I) has been recently introduced in which the binary opinions of the individuals are determined according to the size of their neighboring domains (population having the same opinion). The coarsening dynamics of the equivalent Ising model shows power law behavior and has been found to belong to a new universality class with the dynamic exponent z=1.0±0.01z=1.0 \pm 0.01 and persistence exponent θ0.235\theta \simeq 0.235 in one dimension. The critical behavior has been found to be robust for a large variety of annealed disorder that has been studied. Further, by mapping Model I to a system of random walkers in one dimension with a tendency to walk towards their nearest neighbour with probability ϵ\epsilon, we find that for any ϵ>0.5\epsilon > 0.5, the Model I dynamical behaviour is prevalent at long times.Comment: 12 pages, 10 figures. To be published in "Journal of Physics : Conference Series" (2011

    Stress-responsive pathways and small RNA changes distinguish variable developmental phenotypes caused by MSH1 loss.

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    BACKGROUND: Proper regulation of nuclear-encoded, organelle-targeted genes is crucial for plastid and mitochondrial function. Among these genes, MutS Homolog 1 (MSH1) is notable for generating an assortment of mutant phenotypes with varying degrees of penetrance and pleiotropy. Stronger phenotypes have been connected to stress tolerance and epigenetic changes, and in Arabidopsis T-DNA mutants, two generations of homozygosity with the msh1 insertion are required before severe phenotypes begin to emerge. These observations prompted us to examine how msh1 mutants contrast according to generation and phenotype by profiling their respective transcriptomes and small RNA populations. RESULTS: Using RNA-seq, we analyze pathways that are associated with MSH1 loss, including abiotic stresses such as cold response, pathogen defense and immune response, salicylic acid, MAPK signaling, and circadian rhythm. Subtle redox and environment-responsive changes also begin in the first generation, in the absence of strong phenotypes. Using small RNA-seq we further identify miRNA changes, and uncover siRNA trends that indicate modifications at the chromatin organization level. In all cases, the magnitude of changes among protein-coding genes, transposable elements, and small RNAs increases according to generation and phenotypic severity. CONCLUSION: Loss of MSH1 is sufficient to cause large-scale regulatory changes in pathways that have been individually linked to one another, but rarely described all together within a single mutant background. This study enforces the recognition of organelles as critical integrators of both internal and external cues, and highlights the relationship between organelle and nuclear regulation in fundamental aspects of plant development and stress signaling. Our findings also encourage further investigation into potential connections between organelle state and genome regulation vis-á-vis small RNA feedback

    Analisis Sistem Pengendalian Intern Penyaluran Kredit Pada PD BPR Rokan Hulu

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    Bank yang mempunyai kegiatan utamanya menyalurkan dana kepada masyarakat dalam bentuk kredit mempunyai resiko yang cukup besar, oleh karena itu diperlukan sistem pengendalian intern penyaluran kredit yang efektif untuk mengurangi dan mencegah resiko tersebut. PD. BPR Rokan Hulu merupakan salah satu lembaga keuangan yang kegiatan utamanya adalah menyalurkan dana kepada masyarakat. Penelitian ini bertujuan untuk mengetahui efektifitas penerapan sistem pengendalian intern dalam penyaluran kredit yang dilaksanakan oleh PD. BPR Rokan Hulu. Data penelitian ini diperoleh dari kuesioner dan dokumentasi, teknik analisis data yang digunakan dalam penelitian ini adalah metode analisis deskriptif. Penelitian ini mengunakan metode studi kasus yang berfokus pada sistem pengendalian intern penyaluran kredit pada PD. BPR. Rokan Hulu. Penelitian ini dilakukan dengan menganalisis data tentang komponen-komponen sistem pengendalian intern dari hasil dokumen, dan menghitung hasil keusioner mengunakan rumusan champion.Hasil analisis yang dilakukan menunjukkan bahwa sistem penyaluran kredit yang dilaksanakan oleh PD. BPR Rokan Hulu telah didukung oleh penerapan sistem pengendalian intern yang sangat efektif, berdasarkan hasil jawaban kuesioner yang diperoleh adalah sebesar 92,90% yaitu berada dalam rentang 76% - 100% atau penerapan pengendalian intern sangat efektif dalam menunjang prosedur penyaluran kredit, dan telah memenuhi kelima komponen sistem pengendalian intern yaitu lingkungan pengendalian, penafsiran risiko, aktivitas pengendalian, informasi dan komunikasi, dan pemantauan
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