139 resultados para REMI
Resumo:
We have measured the concentrations of (1) pore-water sulfide and (2) solid-phase pyrite, iron monosulfide (=acid volatile sulfide), elemental sulfur, and extractable and nonextractable organic ("kerogen") sulfur in sediments from Ocean Drilling Program (ODP) Sites 680 and 686. Pore-water sulfide defines classic "bell-shaped" profiles. Maximum concentrations of 6 to 12 mM occur where sulfate is exhausted, or is most depleted, at depths between 15 and 50 mbsf. Sulfide resulting from bacterial sulfate reduction reacts in three ways: (1) some is reoxidized to elemental sulfur in surface sediments; (2) some reacts with detrital iron minerals to form iron monosulfide and pyrite, primarily in the top meter or two of the sediment; and (3) some reacts with, and is incorporated into, kerogen. Incorporation of reduced sulfur into kerogen occurs over the top 15 m of the sediment at both Sites 680 and 686, after the main phase of pyrite formation. Up to 45% of the total sedimentary sulfur is organically bound, and concentrations of 12 wt% sulfur are reached in the kerogen. These values are like those measured in lithologically similar, but more deeply buried, sediments from the Monterey Formation.
Resumo:
En port., grabado: Libreria Estrangera [sic] y Nacional de D. Carlos Bailly Bailliere, Madrid.
Resumo:
Contiene con portadas propias: Recherches et experiences sur les divesr lichens, dont on peut faire usage en medecine et dans les arts ... par M. Amoreux ... - Lichenographie economique ou Histoire des lichens utiles ... / par M. Willemet ... -- Commentatio de vario lichenum usu ... / par M. G. Fr. Hoffmann ...
Resumo:
Text in French.
Resumo:
T.3: " Commentaire historique et juridique par Georges Hubrecht."
Resumo:
"Tire a cent exemplaires sur ce papier Whatman "
Resumo:
A randomized double-blind Phase I Trial was conducted to evaluate safety, tolerability, and immunogenicity of a yellow fever (YF)-dengue 2 (DEN2) chimera (ChimeriVax™-DEN2) in comparison to that of YF vaccine (YF-VAX®). Forty-two healthy YF naïve adults randomly received a single dose of either ChimeriVax™-DEN2 (high dose, 5 log plaque forming units [PFU] or low dose, 3 log PFU) or YF-VAXâ by the subcutaneous route (SC). To determine the effect of YF pre-immunity on the ChimeriVaxTM-DEN2 vaccine, 14 subjects previously vaccinated against YF received a high dose of ChimeriVax™-DEN2 as an open-label vaccine. Most adverse events were similar to YF-VAX® and of mild to moderate intensity, with no serious side-effects. One hundred percent and 92.3% of YF naïve subjects inoculated with 5.0 and 3.0 log10 PFU of ChimeriVaxTM-DEN2, respectively, seroconverted to wt DEN2 (strain 16681); 92% of subjects inoculated with YF-VAX® seroconverted to YF 17D virus but none of YF naïve subjects inoculated with ChimeriVax-DEN2 seroconverted to YF 17D virus. Low seroconversion rates to heterologous DEN serotypes 1, 3, and 4 were observed in YF naïve subjects inoculated with either ChimeriVax™-DEN2 or YF-VAX®. In contrast, 100% of YF immune subjects inoculated with ChimeriVax™-DEN2 seroconverted to all 4 DEN serotypes. Surprisingly, levels of neutralizing antibodies to DEN 1, 2, and 3 viruses in YF immune subjects persisted after 1 year. These data demonstrated that 1) the safety and immunogenicity profile of the ChimeriVax™-DEN2 vaccine is consistent with that of YF-VAX®, and 2) pre-immunity to YF virus does not interfere with ChimeriVaxTM-DEN2 immunization, but induces a long lasting and cross neutralizing antibody response to all 4 DEN serotypes. The latter observation can have practical implications toward development of a dengue vaccine.
Resumo:
Historically, calcitonin gene-related peptide (CGRP) receptors have been divided into two classes, CGRP(1) and CGRP(2).After the cloning of calcitonin receptor-like receptor (CLR) and receptor activity-modifying proteins (RAMPs), it became clear that the CGRP(1) receptor was a complex between CLR and RAMP1. It is now apparent that the CGRP(2) receptor phenotype is the result of CGRP acting at receptors for amylin and adrenomedullin. Accordingly, the term "CGRP(2)" receptor should no longer be used, and the "CGRP(1)" receptor should be known as the "CGRP" receptor.
Resumo:
1 Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) have structural similarities, interact with each others receptors (calcitonin receptor-like receptor (CLR)/receptor-activity-modifying proteins (RAMPs)) and show overlapping biological activities. AM and CGRP receptors are chiefly coupled to cAMP production. In this study, a method of primary dissociated cell culture was used to investigate the presence of AM and CGRP receptors and their effects on cAMP production in embryonic spinal cord cells. 2 Both neuronal and non-neuronal CLR immunopositive cells were present in our model. 3 High affinity, specific [ 125I]-AM binding sites (K(d) 79±9 pM and B(max) 571±34 fmol mg -1 protein) were more abundant than specific [ 125I]-CGRP binding sites (K(d) 12±0.7 pM and B(max) 32±2 fmol mg -1 protein) in embryonic spinal cord cells. 4 Specific [ 125I]-AM binding was competed by related molecules with a ligand selectivity profile of rAM>hAM(22-52)>rCGRPα>CGRP(8-37) ≫[r-(r*,s*)]-N-[2-[[5-amino-1-[[4-(4-pyridinyl)-1-piperazinyl] carbonyl]pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1, 4-dihydro-2-oxo-3(2H)-quinazolinyl)-,1-piperidinecarboxamide (BIBN4096BS). 5 Specific [ 125I]-CGRP binding was competed by rCGRPα>rAM≥ CGRP(8-37)≥BIBN4096BS>hAM(22-52). 6 Cellular levels of cAMP were increased by AM (pEC"5"0 10.2±0.2) and less potently by rCGRPα (pEC"5"0 8.9±0.4). rCGRPα-induced cAMP accumulation was effectively inhibited by CGRP(8-37) (pA"2 7.63±0.44) and hAM(22-52) (pA"2 6.18±0.21) while AM-stimulation of cAMP levels was inhibited by CGRP(8-37) (pA"2 7.41±0.15) and AM(22-52) (pA"2 7.26±0.18). BIBN4096BS only antagonized the effects of CGRP (pA"2 8.40±0.30) on cAMP accumulation. 7 These pharmacological profiles suggest that effects of CGRP are mediated by the CGRP"1 (CLR/RAMP1) receptor in our model while those of AM are related to the activation of the AM"1 (CLR/RAMP2) receptor subtype. © 2006 Nature Publishing Group All rights reserved.
Resumo:
The calcitonin family of peptides comprises calcitonin, amylin two calcitonin gene-related peptides (CGRPs), and adrenomedullin. The first calcitonin receptor was cloned in 1991. Its pharmacology is complicated by the existence of several splice variants. The receptors for the other members the family are made up of subunits. The calcitonin-like receptor (CL receptor) requires a single transmembrane domain protein, termed receptor activity modifying protein, RAMP1, to function as a CGRP receptor. RAMP2 and -3 enable the same CL receptor to behave as an adrenomedullin receptor. Although the calcitonin receptor does not require RAMP to bind and respond to calcitonin, it can associate with the RAMPs, resulting in a series of receptors that typically have high affinity for amylin and varied affinity for CGRP. This review aims to reconcile what is observed when the receptors are reconstituted in vitro with the properties they show in native cells and tissues. Experimental conditions must be rigorously controlled because different degrees of protein expression may markedly modify pharmacology in such a complex situation. Recommendations, which follow International Union of Pharmacology guidelines, are made for the nomenclature of these multimeric receptors.
Resumo:
In recent work we have developed a novel variational inference method for partially observed systems governed by stochastic differential equations. In this paper we provide a comparison of the Variational Gaussian Process Smoother with an exact solution computed using a Hybrid Monte Carlo approach to path sampling, applied to a stochastic double well potential model. It is demonstrated that the variational smoother provides us a very accurate estimate of mean path while conditional variance is slightly underestimated. We conclude with some remarks as to the advantages and disadvantages of the variational smoother. © 2008 Springer Science + Business Media LLC.
Resumo:
This work introduces a new variational Bayes data assimilation method for the stochastic estimation of precipitation dynamics using radar observations for short term probabilistic forecasting (nowcasting). A previously developed spatial rainfall model based on the decomposition of the observed precipitation field using a basis function expansion captures the precipitation intensity from radar images as a set of ‘rain cells’. The prior distributions for the basis function parameters are carefully chosen to have a conjugate structure for the precipitation field model to allow a novel variational Bayes method to be applied to estimate the posterior distributions in closed form, based on solving an optimisation problem, in a spirit similar to 3D VAR analysis, but seeking approximations to the posterior distribution rather than simply the most probable state. A hierarchical Kalman filter is used to estimate the advection field based on the assimilated precipitation fields at two times. The model is applied to tracking precipitation dynamics in a realistic setting, using UK Met Office radar data from both a summer convective event and a winter frontal event. The performance of the model is assessed both traditionally and using probabilistic measures of fit based on ROC curves. The model is shown to provide very good assimilation characteristics, and promising forecast skill. Improvements to the forecasting scheme are discussed
Resumo:
This preliminary report describes work carried out as part of work package 1.2 of the MUCM research project. The report is split in two parts: the ?rst part (Sections 1 and 2) summarises the state of the art in emulation of computer models, while the second presents some initial work on the emulation of dynamic models. In the ?rst part, we describe the basics of emulation, introduce the notation and put together the key results for the emulation of models with single and multiple outputs, with or without the use of mean function. In the second part, we present preliminary results on the chaotic Lorenz 63 model. We look at emulation of a single time step, and repeated application of the emulator for sequential predic- tion. After some design considerations, the emulator is compared with the exact simulator on a number of runs to assess its performance. Several general issues related to emulating dynamic models are raised and discussed. Current work on the larger Lorenz 96 model (40 variables) is presented in the context of dimension reduction, with results to be provided in a follow-up report. The notation used in this report are summarised in appendix.
Resumo:
Recently within the machine learning and spatial statistics communities many papers have explored the potential of reduced rank representations of the covariance matrix, often referred to as projected or fixed rank approaches. In such methods the covariance function of the posterior process is represented by a reduced rank approximation which is chosen such that there is minimal information loss. In this paper a sequential framework for inference in such projected processes is presented, where the observations are considered one at a time. We introduce a C++ library for carrying out such projected, sequential estimation which adds several novel features. In particular we have incorporated the ability to use a generic observation operator, or sensor model, to permit data fusion. We can also cope with a range of observation error characteristics, including non-Gaussian observation errors. Inference for the variogram parameters is based on maximum likelihood estimation. We illustrate the projected sequential method in application to synthetic and real data sets. We discuss the software implementation and suggest possible future extensions.
Resumo:
An interoperable web processing service (WPS) for the automatic interpolation of environmental data has been developed in the frame of the INTAMAP project. In order to assess the performance of the interpolation method implemented, a validation WPS has also been developed. This validation WPS can be used to perform leave one out and K-fold cross validation: a full dataset is submitted and a range of validation statistics and diagnostic plots (e.g. histograms, variogram of residuals, mean errors) is received in return. This paper presents the architecture of the validation WPS and a case study is used to briefly illustrate its use in practice. We conclude with a discussion on the current limitations of the system and make proposals for further developments.