57 research outputs found

    3,5,7-Tripropyl-1-aza­adamantane-4,6,10-triol

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    The title compound, C18H33NO3, was prepared according to a highly diastereoselective hydrogenation procedure from 3,5,7-triallyl-1-aza­adamantane-4,6,10-trione. The crystal structure of the title compound contains two crystallographically independent mol­ecules (Z′ = 2), which are linked by inter­molecular hydrogen bonding into chains. In contrast to the aza­adamantanones, the aza­adamantanetriol core of the title compound does not show any particular C—C bond elongation

    The Astropy Problem

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    The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

    The atacama cosmology telescope: lensing of CMB temperature and polarization derived from cosmic infrared background cross-correlation

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    We present a measurement of the gravitational lensing of the Cosmic Microwave Background (CMB) temperature and polarization fields obtained by cross-correlating the reconstructed convergence signal from the first season of Atacama Cosmology Telescope Polarimeter data at 146 GHz with Cosmic Infrared Background (CIB) fluctuations measured using the Planck satellite. Using an effective overlap area of 92.7 square degrees, we detect gravitational lensing of the CMB polarization by large-scale structure at a statistical significance of 4.5σ4.5\sigma . Combining both CMB temperature and polarization data gives a lensing detection at 9.1σ9.1\sigma significance. A B-mode polarization lensing signal is present with a significance of 3.2σ3.2\sigma . We also present the first measurement of CMB lensing–CIB correlation at small scales corresponding to l>2000l\gt 2000. Null tests and systematic checks show that our results are not significantly biased by astrophysical or instrumental systematic effects, including Galactic dust. Fitting our measurements to the best-fit lensing-CIB cross-power spectrum measured in Planck data, scaled by an amplitude A, gives A=1.020.08+0.12A={1.02}_{-0.08}^{+0.12}(stat.) ± 0.06(syst.), consistent with the Planck results

    Atacama Cosmology Telescope: Component-separated maps of CMB temperature and the thermal Sunyaev-Zel’dovich effect

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    Optimal analyses of many signals in the cosmic microwave background (CMB) require map-level extraction of individual components in the microwave sky, rather than measurements at the power spectrum level alone. To date, nearly all map-level component separation in CMB analyses has been performed exclusively using satellite data. In this paper, we implement a component separation method based on the internal linear combination (ILC) approach which we have designed to optimally account for the anisotropic noise (in the 2D Fourier domain) often found in ground-based CMB experiments. Using this method, we combine multifrequency data from the Planck satellite and the Atacama Cosmology Telescope Polarimeter (ACTPol) to construct the first wide-area (≈2100 sq. deg.), arcminute-resolution component-separated maps of the CMB temperature anisotropy and the thermal Sunyaev-Zel’dovich (tSZ) effect sourced by the inverse-Compton scattering of CMB photons off hot, ionized gas. Our ILC pipeline allows for explicit deprojection of various contaminating signals, including a modified blackbody approximation of the cosmic infrared background (CIB) spectral energy distribution. The cleaned CMB maps will be a useful resource for CMB lensing reconstruction, kinematic SZ cross-correlations, and primordial non-Gaussianity studies. The tSZ maps will be used to study the pressure profiles of galaxies, groups, and clusters through cross-correlations with halo catalogs, with dust contamination controlled via CIB deprojection. The data products described in this paper are available on LAMBDA

    The Atacama Cosmology Telescope: CMB Polarization at 200<<9000200<\ell<9000

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    We report on measurements of the cosmic microwave background (CMB) and celestial polarization at 146 GHz made with the Atacama Cosmology Telescope Polarimeter (ACTPol) in its first three months of observing. Four regions of sky covering a total of 270 square degrees were mapped with an angular resolution of 1.31.3'. The map noise levels in the four regions are between 11 and 17 μ\muK-arcmin. We present TT, TE, EE, TB, EB, and BB power spectra from three of these regions. The observed E-mode polarization power spectrum, displaying six acoustic peaks in the range 200<<3000200<\ell<3000, is an excellent fit to the prediction of the best-fit cosmological models from WMAP9+ACT and Planck data. The polarization power spectrum, which mainly reflects primordial plasma velocity perturbations, provides an independent determination of cosmological parameters consistent with those based on the temperature power spectrum, which results mostly from primordial density perturbations. We find that without masking any point sources in the EE data at <9000\ell<9000, the Poisson tail of the EE power spectrum due to polarized point sources has an amplitude less than 2.42.4 μ\muK2^2 at =3000\ell = 3000 at 95\% confidence. Finally, we report that the Crab Nebula, an important polarization calibration source at microwave frequencies, has 8.7\% polarization with an angle of 150.7±0.6150.7^\circ \pm 0.6^\circ when smoothed with a 55' Gaussian beam.Comment: 16 pages, 15 figures, 5 table

    La mesure de la polarisation avec Planck HFI : Calibration, effets systématiques et sources compactes

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    During the last couple of decades, studying the cosmic microwave back- ground (CMB) temperature anisotropies has been the most powerful probe to establish our current standard cosmological model and to constrain its parameters. In spite of the impressive agreement between the model and a large variety of observations, there are still some remaining issues that polarization measurement of the CMB could help disentangle. In particu- lar, primordial B-modes of polarization are widely considered as being a smoking gun of the hypothetical period of inflation, and detecting them is one of the most important goal in cosmology for the next few years.The measurement of CMB polarization is one of Planck’s ESA mission goals. Measuring polarization is challenging though ; the relative amplitudes of the signals in temperature and polarization require a strict control of systematic effects. This thesis present my work on calibration and characterization of the systematic effects for the Planck HFI instrument, as well as a study of compact sources.I propose a new method to extract compact sources photometry, based on time domain analysis instead of maps, and apply it to study polarization and time variability of astrophysical sources seen by Planck ; a particular at- tention is dedicated to the Crab nebula. This analysis is also used to test the HFI calibration and study various systematic effects, such as beam shapes or bandpass effects, that can affect this calibration. A method to calibrate the polarization parameters of HFI detectors (polarization efficiencies and orientations in the focal plane) is also proposed and tested on simulations.L'étude des anisotropies de température du rayonnement fossile durant les vingt dernières années a permis d’assoir notre modèle standard cosmologique, et de contraindre fortement ses paramètres. En dépit de la robustesse du modèle proposé, de nombreuses questions persistent, et la mesure de la polarisation de ce rayonnement pourrait permettre de répondre à certaines de ces questions. En particulier, une détection des modes B de polarisation permettrait de sonder la phase d’inflation qui se serait produite dans l’univers primordial.Mesurer la polarisation du fond diffus cosmologique est l’un des objectifs de la mission spatiale européenne Planck. En raison de l’échelle d’amplitude relative du signal en température, modes E et modes B de polarisation, cette mesure requiert un contrôle drastique des effets systématiques liés à l’instrument. Cette thèse présente mon travail sur la calibration et l’étude des effets systématiques affectant la mesure de polarisation pour l’instrument Planck HFI, ainsi que l’étude de sources compactes.Une nouvelle méthode de photométrie des sources, basée sur les données temporelles plutôt que sur les cartes, est proposée et utilisée pour étudier la polarisation et les variations temporelles de sources astrophysiques observées par Planck (en particulier la nébuleuse du Crabe). Cette étude de sources compactes a aussi permis de tester la calibration de l’instrument et d’étudier certains effets systématiques (forme des lobes, bandes passantes des détecteurs, fonction de transfert des bolomètres ...) pouvant affecter cette calibration. Enfin, une méthode pour la calibration polarisée est proposée et testée sur des simulations

    La mesure de la polarisation avec Planck HFI (calibration, effets systématiques et sources compactes)

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    L'étude des anisotropies de température du rayonnement fossile durant les vingt dernières années a permis d'assoir notre modèle standard cosmologique, et de contraindre fortement ses paramètres. En dépit de la robustesse du modèle proposé, de nombreuses questions persistent, et la mesure de la polarisation de ce rayonnement pourrait permettre de répondre à certaines de ces questions. En particulier, une détection des modes B de polarisation permettrait de sonder la phase d'inflation qui se serait produite dans l'univers primordial. Mesurer la polarisation du fond diffus cosmologique est l'un des objectifs de la mission spatiale européenne Planck. En raison de l'échelle d'amplitude relative du signal en température, modes E et modes B de polarisation, cette mesure requiert un contrôle drastique des effets systématiques liés à l'instrument. Cette thèse présente mon travail sur la calibration et l'étude des effets systématiques affectant la mesure de polarisation pour l'instrument Planck HFI, ainsi que l'étude de sources compactes. Une nouvelle méthode de photométrie des sources, basée sur les données temporelles plutôt que sur les cartes, est proposée et utilisée pour étudier la polarisation et les variations temporelles de sources astrophysiques observées par Planck (en particulier la nébuleuse du Crabe). Cette étude de sources compactes a aussi permis de tester la calibration de l'instrument et d'étudier certains effets systématiques (forme des lobes, bandes passantes des détecteurs, fonction de transfert des bolomètres ...) pouvant affecter cette calibration. Enfin, une méthode pour la calibration polarisée est proposée et testée sur des simulations.During the last couple of decades, studying the cosmic microwave background (CMB) temperature ani has been the most powerful probe to establish our current standard cosmological model and to constraint its parameters. In spite of the impressive agreement between the model and a large variety of observation: there are still some remaining issues that polarization measurement of the CMB could help disentangle. In particular primordial B-modes of polarisation are widely considered as being a smoking gun of the hypothetical period of inflation, and detecting them is one of the most important goal in cosmology for the next few years.The measurement of CMB polarisation is one of Planck's ESA mission goals. Measuring polarisation is challenging though; the relative amplitudes of the signals in temperature and polarisation require a strict control of systematic effects. This thesis present my work on calibration and characterization of the systematic effects for the Planck HFI instrument, as well as a study of compact sources. I propose a new method to extract compact sources photometry, based on time domain analysis instead of maps, and apply it to study polarisation and time variability of astrophysical sources seen by Planck; a particular attention is dedicated to the Crab nebula. This analysis is also used to test the HFI calibration and study various systematic effects, such as beam shapes or bandpass effects, that can affect this calibration. A method to calibrate the polarisation parameters of HFI detectors (polarization efficienciescand orientations in the focal plane) is also proposed and tested on simulations.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

    Classifying CMB time-ordered data through deep neural networks

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    International audienceThe Cosmic Microwave Background (CMB) has been measured over a wide range of multipoles. Experiments with arcminute resolution like the Atacama Cosmology Telescope (ACT) have contributed to the measurement of primary and secondary anisotropies, leading to remarkable scientific discoveries. Such findings require careful data selection in order to remove poorly behaved detectors and unwanted contaminants. The current data classification methodology used by ACT relies on several statistical parameters that are assessed and fine-tuned by an expert. This method is highly time-consuming and band or season-specific, which makes it less scalable and efficient for future CMB experiments. In this work, we propose a supervised machine learning model to classify detectors of CMB experiments. The model corresponds to a deep convolutional neural network. We tested our method on real ACT data, using the 2008 season, 148 GHz, as training set with labels provided by the ACT data selection software. The model learns to classify time-streams starting directly from the raw data. For the season and frequency considered during the training, we find that our classifier reaches a precision of 99.8 per cent. For 220 and 280 GHz data, season 2008, we obtained 99.4 per cent and 97.5 per cent of precision, respectively. Finally, we performed a cross-season test over 148 GHz data from 2009 and 2010 for which our model reaches a precision of 99.8 per cent and 99.5 per cent, respectively. Our model is about 10x faster than the current pipeline, making it potentially suitable for real-time implementations

    An expeditious access to 5-pyrimidinol derivatives from cyclic methylglyoxal diadducts, formation of argpyrimidines under physiological conditions and discovery of new CFTR inhibitors.

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    IF : 2,88International audienceIn the study of previously reported modulators of CFTR chloride channels that are cyclic methylglyoxal (MG) diadducts (CMGD) to aromatic α-aminoazaheterocycles, we optimized a new expeditious one pot route for preparing in water novel aromatic polycyclic azaheterocycles and described 5-pyrimidinols antioxidants through the formation of 2-oxoaldehyde diadducts to aromatic α-aminoazaheterocycles, amidines, guanidines and thiourea. In regard to the importance as biomarkers of diabetic complications of the 5-pyrimidinols "argpyrimidines" formed in proteins from MG and arginine residues, we demonstrated that argpyrimidines are slowly formed under physiological conditions from CMGD to arginine derivatives according to the synthesis route described. Among the 5-pyrimidinol derivatives prepared, two polycyclic derivatives appeared to inhibit strongly the activity of CFTR channels in wt-CHO cells

    Principles and applications of molecular biology techniques for the microbiological diagnosis of acute post-operative endophthalmitis.

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    International audience: The systematic microbiological evaluation of endophthalmitis allows the confirmation of the infectious nature of the disease and the possible adaptation of treatment at the individual level and, at the collective level, the epidemiological characterization of the bacterial spectrum of endophthalmitis. Long reserved for research, the use of molecular biology techniques to complement conventional culture techniques has become important for the diagnosis of endophthalmitis in recent years. These new diagnostic techniques are particularly useful for the microbiological study of bacteria that are difficult or impossible to grow because of their intrinsic properties, their presence in only a small inoculum, their sequestration on prosthetic materials, or their inactivation by prior antibiotic treatment. These techniques are based on the polymerase chain reaction (PCR), which allows the amplification and detection of extracted bacterial deoxyribonucleic acid (DNA) that is initially present in minute quantities in an ocular sample. In practice, these conventional or real-time PCRs allow either the a priori detection of bacterial DNA (universal PCR) or the identification of a specific DNA fragment of a bacterial genus or species (specific PCR). New techniques of PCR will allow more rapid bacterial identification and also characterization of genotypic properties, such as genes of virulence or antibiotic resistance
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