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Sample records for corot cp2 target

  1. Surface structure of the CoRoT CP2 target star HD 50773

    CERN Document Server

    Lüftinger, T; Weiss, W; Petit, P; Aurière, M; Nesvacil, N; Gruberbauer, M; Shulyak, D; Alecian, E; Baglin, A; Baudin, F; Catala, C; Donati, J -F; Kochukhov, O; Michel, E; Piskunov, N; Roudier, T; Samadi, R

    2009-01-01

    We compare surface maps of the chemically peculiar star HD 50773 produced with a Bayesian technique and based on high quality CoRoT photometry with those derived from rotation phase resolved spectropolarimetry. The goal is to investigate the correlation of surface brightness with surface chemical abundance distribution and the stellar magnetic field. The rotational period of the star was determined from a nearly 60 day long continuous light curve obtained during the initial run of CoRoT. Using a Bayesian approach to star-spot modelling, which in this work is applied for the first time for the photometric mapping of a CP star, we derived longitudes, latitudes and radii of four different spot areas. Additional parameters like stellar inclination and the spot's intensities were also determined. The CoRoT observations triggered an extensive ground-based spectroscopic and spectropolarimetric observing campaign and enabled us to obtain 19 different high resolution spectra in Stokes parameters I and V with NARVAL, E...

  2. Targeted disruption of the CP2 gene, a member of the NTF family of transcription factors.

    Science.gov (United States)

    Ramamurthy, L; Barbour, V; Tuckfield, A; Clouston, D R; Topham, D; Cunningham, J M; Jane, S M

    2001-03-16

    The NTF-like family of transcription factors have been implicated in developmental regulation in organisms as diverse as Drosophila and man. The two mammalian members of this family, CP2 (LBP-1c/LSF) and LBP-1a (NF2d9), are highly related proteins sharing an overall amino acid identity of 72%. CP2, the best characterized of these factors, is a ubiquitously expressed 66-kDa protein that binds the regulatory regions of many diverse genes. Consequently, a role for CP2 has been proposed in globin gene expression, T-cell responses to mitogenic stimulation, and several other cellular processes. To elucidate the in vivo role of CP2, we have generated mice nullizygous for the CP2 allele. These animals were born in a normal Mendelian distribution and displayed no defects in growth, behavior, fertility, or development. Specifically, no perturbation of hematopoietic differentiation, globin gene expression, or immunological responses to T- and B-cell mitogenic stimulation was observed. RNA and protein analysis confirmed that the nullizygous mice expressed no full-length or truncated version of CP2. Electrophoretic mobility shift assays with nuclear extracts from multiple tissues demonstrated loss of CP2 DNA binding activity in the -/- lines. However, a slower migrating complex that was ablated with antiserum to NF2d9, the murine homologue of LBP-1a, was observed with these extracts. Furthermore, we demonstrate that recombinant LBP-1a can bind to known CP2 consensus sites and form protein complexes with previously defined heteromeric partners of CP2. These results suggest that LBP-1a/NF2d9 may compensate for loss of CP2 expression in vivo and that further analysis of the role of the NTF family of proteins requires the targeting of the NF2d9 gene.

  3. Photometry of Be Stars in the vicinity of COROT primary targets for asteroseismology

    CERN Document Server

    Gutiérrez-Soto, J; Suso, J; Hubert, A M; Floquet, M; Garrido, R

    2003-01-01

    We present differential photometry of Be stars close to potential COROT primary targets for asteroseismology. Several stars are found to be short period variables. We propose them to be considered as secondary targets in the COROT asteroseismology fields.

  4. Stellar classification of CoRoT targets

    CERN Document Server

    Damiani, C; Moutou, C; Deleuil, M; Ysard, N; Baudin, F; Deeg, H

    2016-01-01

    The CoRoT faint stars channel observed about 163 600 targets to detect transiting planetary companions. Because CoRoT targets are faint (11< r <16) and close to the galactic plane, only a small subsample has been observed spectroscopically. We describe the latest classification scheme used to derive the spectral type of CoRoT targets, which is based on broadband multi-colour photometry. We assess the accuracy of this spectral classification for the first time. We find that the classification method performs better for stars that were observed during the mission-dedicated photometric ground-based campaigns.The luminosity class is wrong for less than 7% of the targets. Generally, the effective temperature of stars classified as early type (O, B, and A) is overestimated. Conversely, the temperature of stars classified as later type tends to be underestimated. This is mainly due to the adverse effect of interstellar reddening. We find that the median error on the effective temperature is less than 5% for dw...

  5. MiR-218 targets MeCP2 and inhibits heroin seeking behavior

    Science.gov (United States)

    Yan, Biao; Hu, Zhaoyang; Yao, Wenqing; Le, Qiumin; Xu, Bo; Liu, Xing; Ma, Lan

    2017-01-01

    MicroRNAs (miRNAs) are a class of evolutionarily conserved, 18–25 nucleotide non-coding sequences that post-transcriptionally regulate gene expression. Recent studies implicated their roles in the regulation of neuronal functions, such as learning, cognition and memory formation. Here we report that miR-218 inhibits heroin-induced behavioral plasticity. First, network propagation-based method was used to predict candidate miRNAs that played potential key roles in regulating drug addiction-related genes. Microarray screening was also carried out to identify miRNAs responding to chronic heroin administration in the nucleus accumbens (NAc). Among the collapsed miRNAs, top-ranked miR-218 was decreased after chronic exposure to heroin. Lentiviral overexpression of miR-218 in NAc could inhibit heroin-induced reinforcement in both conditioned place preference (CPP) test and heroin self-administration experiments. Luciferase activity assay indicated that miR-218 could regulate 3′ untranslated regions (3′ UTR) of multiple neuroplasticity-related genes and directly target methyl CpG binding protein 2 (Mecp2). Consistently, Mecp2308/y mice exhibited reduced heroin seeking behavior in CPP test. These data reveal a functional role of miR-218 and its target, MeCP2, in the regulation of heroin-induced behavioral plasticity. PMID:28074855

  6. MiR-130a regulates neurite outgrowth and dendritic spine density by targeting MeCP2

    Directory of Open Access Journals (Sweden)

    Yunjia Zhang

    2016-06-01

    Full Text Available ABSTRACT MicroRNAs (miRNAs are critical for both development and function of the central nervous system. Significant evidence suggests that abnormal expression of miRNAs is associated with neurodevelopmental disorders. MeCP2 protein is an epigenetic regulator repressing or activating gene transcription by binding to methylated DNA. Both loss-of-function and gain-of-function mutations in the MECP2 gene lead to neurodevelopmental disorders such as Rett syndrome, autism and MECP2 duplication syndrome. In this study, we demonstrate that miR-130a inhibits neurite outgrowth and reduces dendritic spine density as well as dendritic complexity. Bioinformatics analyses, cell cultures and biochemical experiments indicate that miR-130a targets MECP2 and down-regulates MeCP2 protein expression. Furthermore, expression of the wild-type MeCP2, but not a loss-of-function mutant, rescues the miR-130a-induced phenotype. Our study uncovers the MECP2 gene as a previous unknown target for miR-130a, supporting that miR-130a may play a role in neurodevelopment by regulating MeCP2. Together with data from other groups, our work suggests that a feedback regulatory mechanism involving both miR-130a and MeCP2 may serve to ensure their appropriate expression and function in neural development.

  7. On the variability of HD 170699 - a possible COROT target

    CERN Document Server

    Alvarez, M; Parrao, L; Pena, J H; Machado, L Fox; Poretti, E; Martin-Ruiz, S; Amado, P; Garrido, R; Aerts, C; Csurby, Z; Paparo, M

    2008-01-01

    We present the analysis of the variability of HD 170699, a COROT star showing the characteristics of a non evolutionary Delta Scuti star with high rotational velocity. There is a clear period of 10.45 c/d with 5.29 mmag amplitude in the y filter. From the data, it can be seen that the star shows multi-periodicity and it is necessary to add more frequencies to adjust the observations

  8. Characterization of CoRoT target fields with BEST: Identification of periodic variable stars in the IR01 field

    CERN Document Server

    Kabath, P; Erikson, A; Hedelt, P; Rauer, H; Titz, R; Wiese, T; 10.1086/521554

    2009-01-01

    We report on observations of the CoRoT IR01 field with the Berlin Exoplanet Search Telescope (BEST). BEST is a small aperture telescope with a wide field of view (FOV). It is dedicated to search for variable stars within the target fields of the CoRoT space mission to aid in minimizing false-alarm rates and identify potential targets for additional science. CoRoT's observational programm started in February 2007 with the "initial run" field (IR01) observed for about two months. BEST observed this field for 12 nights spread over three months in winter 2006. From the total of 30426 stars observed in the IR01 field 3769 were marked as suspected variable stars and 54 from them showed clear periodicity. From these 19 periodic stars are within the part of the CoRoT FOV covered in our data set.

  9. MeCP2 deficiency disrupts axonal guidance, fasciculation, and targeting by altering Semaphorin 3F function

    NARCIS (Netherlands)

    Degano, Alicia L.; Pasterkamp, R. Jeroen; Ronnett, Gabriele V.

    2009-01-01

    Rett syndrome (RTT) is an autism spectrum disorder that results from mutations in the transcriptional regulator methyl-CpG binding protein 2 (MECP2). In the present work, we demonstrate that MeCP2 deficiency disrupts the establishment of neural connections before synaptogenesis. Using both in vitro

  10. The gamma Dor CoRoT target HD49434. I-Results from the ground-based campaign

    OpenAIRE

    Uytterhoeven, K.; Mathias, P.; Poretti, E.; RAINER, M.; Martin-Ruiz, S.; Rodriguez, E.; Amado, P. J.; LeContel, D.; Jankov, S.; Niemczura, E.; Pollard, K.; Brunsden, E.; M. Paparo; Costa, V; Valtier, J.-C.

    2008-01-01

    Context: We present the results of an extensive ground-based photometric and spectroscopic campaign on the gamma Dor CoRoT target HD49434. This campaign was preparatory to the CoRoT satellite observations, which took place from October 2007 to March 2008. Results: The frequency analysis clearly shows the presence of four frequencies in the 0.2-1.7 c/d interval, as well as six frequencies in the 5-12 c/d domain. The low frequencies are typical for gamma Dor variables while the high frequencies...

  11. Characterization of CoRoT target fields with BEST: Identification of periodic variable stars in the LRa1 field

    CERN Document Server

    Kabath, P; Erikson, A; Hedelt, P; Von Paris, P; Rauer, H; Renner, S; Titz, R; Wiese, T

    2009-01-01

    In this paper we report on observations of the CoRoT LRa1 field with the Berlin Exoplanet Search Telescope (BEST). The current paper is part of the series of papers describing the results of our stellar variability survey. BEST is a small aperture telescope with a wide field-of-view (FOV). It is dedicated to search for stellar variability within the target fields of the CoRoT space mission to aid in minimizing false-alarm rates and identify potential targets for additional science. The LRa1 field is CoRoT's third observed field and the second long run field located in the galactic anticenter direction. We observed the LRa1 stellar field on 23 nights between November and March 2005/2006. From 6099 stars marked as variable, 39 were classified as periodic variable stars and 27 of them are within the CoRoT FOV. We also confirmed the variability for 4 stars listed in GCVS catalog.

  12. Fuzzy CP2

    CERN Document Server

    Alexanian, G G; Immirzi, G; Ydri, B

    2001-01-01

    Regularization of quantum field theories (QFT's) can be achieved by quantizing the underlying manifold (spacetime or spatial slice) thereby replacing it by a non-commutative matrix model or a ``fuzzy manifold''. Such discretization by quantization is remarkably successful in preserving symmetries and topological features, and altogether overcoming the fermion-doubling problem. In this paper, we report on our work on the ``fuzzification'' of the four-dimensional CP2 and its QFT's. CP2 is not spin, but spin${}_c$. Its Dirac operator has many unique features. They are explained and their fuzzy versions are described.

  13. Precise Modeling of the Exoplanet Host Star and CoRoT Main Target HD 52265

    CERN Document Server

    Escobar, M E; Ballot, J; Charpinet, S; Dolez, N; Hui-Bon-Hoa, A; Vauclair, G; Gizon, L; Mathur, S; Quirion, P O; Stahn, T

    2012-01-01

    This paper presents a detailed and precise study of the characteristics of the Exoplanet Host Star and CoRoT main target HD 52265, as derived from asteroseismic studies. The results are compared with previous estimates, with a comprehensive summary and discussion. The basic method is similar to that previously used by the Toulouse group for solar-type stars. Models are computed with various initial chemical compositions and the computed p-mode frequencies are compared with the observed ones. All models include atomic diffusion and the importance of radiative accelerations is discussed. Several tests are used, including the usual frequency combinations and the fits of the \\'echelle diagrams. The possible surface effects are introduced and discussed. Automatic codes are also used to find the best model for this star (SEEK, AMP) and their results are compared with that obtained with the detailed method. We find precise results for the mass, radius and age of this star, as well as its effective temperature and lu...

  14. Determination of the Contamination Rate and the Associated Error for Targets Observed by CoRoT in the Exoplanet Channel

    Science.gov (United States)

    Gardes, B.; Chabaud, P.-Y.; Guterman, P.

    2012-09-01

    In the CoRoT exoplanet field of view, photometric measurements are obtained by aperture integration using a generic collection of masks. The total flux held within the photometric mask may be split in two parts, the target flux itself and the flux due to the nearest neighbours considered as contaminants. So far ExoDat (http://cesam.oamp.fr/exodat) gives a rough estimate of the contamination rate for all potential exoplanet targets (level-0) based on generic PSF shapes built before CoRoT launch. Here, we present the updated estimate of the contamination rate (level-1) with its associated error. This estimate is done for each target observed by CoRoT in the exoplanet channel using a new catalog of PSF built from the first available flight images and taking into account the line of sight of the satellite (i.e. the satellite orientation).

  15. The gamma Dor CoRoT target HD49434. I-Results from the ground-based campaign

    CERN Document Server

    Uytterhoeven, K; Poretti, E; Rainer, M; Martin-Ruiz, S; Rodríguez, E; Amado, P J; LeContel, D; Jankov, S; Niemczura, E; Pollard, K; Brunsden, E; Paparo, M; Costa, V; Valtier, J -C; Garrido, R; Marin, A J; Suárez, J C; Kilmartin, P H; Chapellier, E; Rodriguez-Lopez, C; Aceituno, F J; Casanova, V; Rolland, A; Olivares, I

    2008-01-01

    Context: We present the results of an extensive ground-based photometric and spectroscopic campaign on the gamma Dor CoRoT target HD49434. This campaign was preparatory to the CoRoT satellite observations, which took place from October 2007 to March 2008. Results: The frequency analysis clearly shows the presence of four frequencies in the 0.2-1.7 c/d interval, as well as six frequencies in the 5-12 c/d domain. The low frequencies are typical for gamma Dor variables while the high frequencies are common for delta Sct pulsators. We propose the frequency 2.666 c/d as a possible rotational frequency. All modes, for which an identification was possible, seem to be high-degree modes (3 <= l <= 8). We did not find evidence for a possible binary nature of HD49434. The element abundances we derived are consistent with the values obtained in previous analyses. Conclusions: We classify the gamma Dor star HD49434 as a hybrid pulsator, which pulsates simultaneously in p- and g-modes. This finding makes HD49434 an e...

  16. Characterization of CoRoT Target Fields with the Berlin Exoplanet Search Telescope: Identification of Periodic Variable Stars in the LRa1 Field

    CERN Document Server

    Kabath, P; Erikson, A; Hedelt, P; Von Paris, P; Rauer, H; Renner, S; Titz, R; Karoff, C; 10.1088/0004-6256/136/2/654

    2009-01-01

    In this paper, we report on observations of the CoRoT LRa1 field with the Berlin Exoplanet Search Telescope (BEST). The current paper is part of a series of papers describing the results of our stellar variability survey. The BEST is a small aperture telescope with a wide field of view (FOV). It is dedicated to searching for stellar variability within the target fields of the CoRoT space mission to aid in minimizing false-alarm rates and identify potential targets for additional science. The LRa1 field is CoRoT's second long run field located in the galactic anticenter direction. We observed the LRa1 stellar field on 23 nights between November and March 2005/2006. From 6099 stars marked as variable, 39 were classified as periodic variable stars and 27 of them are within the CoRoT FOV. We also confirmed the variability for four stars listed in the General Catalogue of Variable Stars (GCVS).

  17. Genetic modifiers of MeCP2 function in Drosophila.

    Directory of Open Access Journals (Sweden)

    Holly N Cukier

    2008-09-01

    Full Text Available The levels of methyl-CpG-binding protein 2 (MeCP2 are critical for normal post-natal development and function of the nervous system. Loss of function of MeCP2, a transcriptional regulator involved in chromatin remodeling, causes classic Rett syndrome (RTT as well as other related conditions characterized by autism, learning disabilities, or mental retardation. Increased dosage of MeCP2 also leads to clinically similar neurological disorders and mental retardation. To identify molecular mechanisms capable of compensating for altered MeCP2 levels, we generated transgenic Drosophila overexpressing human MeCP2. We find that MeCP2 associates with chromatin and is phosphorylated at serine 423 in Drosophila, as is found in mammals. MeCP2 overexpression leads to anatomical (i.e., disorganized eyes, ectopic wing veins and behavioral (i.e., motor dysfunction abnormalities. We used a candidate gene approach to identify genes that are able to compensate for abnormal phenotypes caused by MeCP2 increased activity. These genetic modifiers include other chromatin remodeling genes (Additional sex combs, corto, osa, Sex combs on midleg, and trithorax, the kinase tricornered, the UBE3A target pebble, and Drosophila homologues of the MeCP2 physical interactors Sin3a, REST, and N-CoR. These findings demonstrate that anatomical and behavioral phenotypes caused by MeCP2 activity can be ameliorated by altering other factors that might be more amenable to manipulation than MeCP2 itself.

  18. Fundamental properties of Kepler and CoRoT targets - III. Tuning scaling relations using the first adiabatic exponent

    Science.gov (United States)

    Yıldız, M.; Çelik Orhan, Z.; Kayhan, C.

    2016-10-01

    So-called scaling relations based on oscillation frequencies have the potential to reveal the mass and radius of solar-like oscillating stars. In the derivation of these relations, it is assumed that the first adiabatic exponent at the surface (Γ_{1s}) of such stars is constant. However, by constructing interior models for the mass range 0.8-1.6 M⊙, we show that Γ _{1s} is not constant at stellar surfaces for the effective temperature range with which we deal. Furthermore, the well-known relation between large separation and mean density also depends on Γ _{1s}. Such knowledge is the basis for our aim of modifying the scaling relations. There are significant differences between masses and radii found from modified and conventional scaling relations. However, a comparison of predictions of these relations with the non-asteroseismic observations of Procyon A reveals that new scaling relations are effective in determining the mass and radius of stars. In the present study, solar-like oscillation frequencies of 89 target stars (mostly Kepler and CoRoT) were analysed. As well as two new reference frequencies (νmin1 and νmin2) found in the spacing of solar-like oscillation frequencies of stellar interior models, we also take into account νmin0. In addition to the frequency of maximum amplitude, these frequencies have a very strong diagnostic potential in the determination of fundamental properties. The present study applies the derived relations from the models to the solar-like oscillating stars, and computes their effective temperatures using purely asteroseismic methods. There are in general very close agreements between effective temperatures from asteroseismic and non-asteroseismic (spectral and photometric) methods. For the Sun and Procyon A, for example, the agreement is almost total.

  19. The variability of the CoRoT target HD171834: gamma Dor pulsations and/or activity?

    CERN Document Server

    Uytterhoeven, K; Baglin, A; Rainer, M; Poretti, E; Amado, P; Chapellier, E; Mantegazza, L; Pollard, K; Suarez, J C; Kilmartin, P M; Sato, K H; Garcia, R A; Auvergne, M; Michel, E; Samadi, R; Catala, C; Baudin, F

    2011-01-01

    We present the preliminary results of a frequency and line-profile analysis of the CoRoT gamma Dor candidate HD171834. The data consist of 149 days of CoRoT light curves and a ground-based dataset of more than 1400 high-resolution spectra, obtained with six different instruments. Low-amplitude frequencies between 0 and 5 c/d, dominated by a frequency near 0.96 c/d and several of its harmonics, are detected. These findings suggest that HD171834 is not a mere gamma Dor pulsator and that stellar activity plays an important role in its variable behaviour. Based on CoRoT space data and on ground-based observations with ESO Telescopes at the La Silla Observatory under the ESO Large Programmes ESO LP 178.D-0361 and ESO LP 182.D-0356 (FEROS/2.2m and HARPS/3.6m), and data collected with FOCES/2.2m at the Centro Astronomico Hispano Aleman at Calar Alto, SOPHIE/1.93m at Observatoire de Haute Provence, FIES/NOT at Observatorio del Roque de los Muchachos, and HERCULES/1.0m at Mount John University Observatory.

  20. Close-up of primary and secondary asteroseismic CoRoT targets and the ground-based follow-up observations

    CERN Document Server

    Uytterhoeven, K; Rainer, M; Mantegazza, L; Zima, W; Aerts, C; Morel, T; Miglio, A; Lefever, K; Amado, P J; Mathias, P; Valtier, J C; Paparo, M; Benko, J M; CoRoT/SWG, the

    2007-01-01

    To optimise the science results of the asteroseismic part of the CoRoT satellite mission a complementary simultaneous ground-based observational campaign is organised for selected CoRoT targets. The observations include both high-resolution spectroscopic and multi-colour photometric data. We present the preliminary results of the analysis of the ground-based observations of three targets. A line-profile analysis of 216 high-resolution FEROS spectra of the delta Sct star HD 50844 reveals more than ten pulsation frequencies in the frequency range 5-18 c/d, including possibly one radial fundamental mode (6.92 c/d). Based on more than 600 multi-colour photometric datapoints of the beta Cep star HD180642, spanning about three years and obtained with different telescopes and different instruments, we confirm the presence of a dominant radial mode nu1=5.48695 c/d, and detect also its first two harmonics. We find evidence for a second mode nu2=0.3017 c/d, possibly a g-mode, and indications for two more frequencies in...

  1. miRSNPs of miR1274 and miR3202 Genes that Target MeCP2 and DNMT3b Are Associated with Lung Cancer Risk: A Study Conducted on MassARRAY Genotyping.

    Science.gov (United States)

    Ozbayer, Cansu; Degirmenci, Irfan; Ustuner, Derya; Ak, Guntulu; Saydam, Faruk; Colak, Ertugrul; Gunes, Hasan Veysi; Metintas, Muzaffer

    2016-01-01

    Genetic variants of miRNAs that target DNMTs and MBDs involved in DNA methylation were scanned with current databases, and 35 miRSNPs in 22 miRNA genes were identified. The aim of the study was to determine the association between these variants of miRNA genes and lung cancer (LC). DNA samples were isolated from blood samples and genotyped using a Sequenom MassARRAY System. An association between the rs188912830 gene variant of miR3202 that targets the MeCP2 protein and LC was indicated in both subtypes. The presence of the C-allele in patients with LC and its subtypes was significantly lower, and the absence of the C-allele was determined to increase the risk of LC by 7,429-times compared to the presence (p=0,010). The rs318039 gene variant of miR1274 that targets DNMT3b was found to be associated with LC subtypes. When allele distributions were compared, the numbers of individuals with the C-allele were significantly lower in the NSCLC and SCLC groups. No significant associations were found for the rs72563729 variant of the miR200b gene that targets DNMT3a or for the rs145416750 variant of the miR513c gene that targets TRDMT1. The other 33 variants were found to be ancestral genotypes. Consequently, rs188912830 and rs318039 variations were associated with LC subtypes. Importantly, this study is the first to indicate the functional characterisation of miRSNPs of genes that target DNA methylation.

  2. Astrocyte-specific regulation of hMeCP2 expression in Drosophila

    Directory of Open Access Journals (Sweden)

    David L. Hess-Homeier

    2014-10-01

    Full Text Available Alterations in the expression of Methyl-CpG-binding protein 2 (MeCP2 either by mutations or gene duplication leads to a wide spectrum of neurodevelopmental disorders including Rett Syndrome and MeCP2 duplication disorder. Common features of Rett Syndrome (RTT, MeCP2 duplication disorder, and neuropsychiatric disorders indicate that even moderate changes in MeCP2 protein levels result in functional and structural cell abnormalities. In this study, we investigated two areas of MeCP2 pathophysiology using Drosophila as a model system: the effects of MeCP2 glial gain-of-function activity on circuits controlling sleep behavior, and the cell-type specific regulation of MeCP2 expression. In this study, we first examined the effects of elevated MeCP2 levels on microcircuits by expressing human MeCP2 (hMeCP2 in astrocytes and distinct subsets of amine neurons including dopamine and octopamine (OA neurons. Depending on the cell-type, hMeCP2 expression reduced sleep levels, altered daytime/nighttime sleep patterns, and generated sleep maintenance deficits. Second, we identified a 498 base pair region of the MeCP2e2 isoform that is targeted for regulation in distinct subsets of astrocytes. Levels of the full-length hMeCP2e2 and mutant RTT R106W protein decreased in astrocytes in a temporally and spatially regulated manner. In contrast, expression of the deletion Δ166 hMeCP2 protein was not altered in the entire astrocyte population. qPCR experiments revealed a reduction in full-length hMeCP2e2 transcript levels suggesting transgenic hMeCP2 expression is regulated at the transcriptional level. Given the phenotypic complexities that are caused by alterations in MeCP2 levels, our results provide insight into distinct cellular mechanisms that control MeCP2 expression and link microcircuit abnormalities with defined behavioral deficits.

  3. Exploring the sources of p-mode frequency shifts in the CoRoT target HD 49933

    CERN Document Server

    Liu, Zhie; Yang, Wuming; Li, Tanda; Liu, Kang; Tian, Zhijia; Ge, Zhishuai; Yu, Jie

    2014-01-01

    The oscillations of the solar-like star HD 49933 have been observed thoroughly by CoRot. Two dozens of frequency shifts, which are closely related with the change in magnetic activity, have been measured. To explore the effects of the magnetic activity on the frequency shifts, we calculate frequency shifts for the radial and $l = 1$ p-modes of HD 49933 with the general variational method, which evaluates the shifts using a spatial integral of the product of a kernel and some sources. The theoretical frequency shifts well reproduce the observation. The magnitudes and positions of the sources are determined according to the $\\chi^2$ criterion. We predict the source that contributes to both $l = 0$ and $l = 1$ modes is located at $0.48 - 0.62$Mm below the stellar surface. In addition, based on the assumption that $A_{0}$ is proportional to the change in the MgII activity index $\\Delta{i}_{MgII}$, we obtained that the change of MgII index between minimum and maximum of HD 49933 cycle period is about 0.665. The ma...

  4. Gravito-inertial and pressure modes detected in the B3 IV CoRoT target HD 43317

    CERN Document Server

    Pápics, P I; Baglin, A; Poretti, E; Aerts, C; Degroote, P; Tkatchenko, A; Morel, T; Zima, W; Niemczura, E; Rainer, M; Hareter, M; Baudin, F; Catala, C; Michel, E; Samadi, R; Auvergne, M

    2012-01-01

    Context. OB stars are important building blocks of the Universe, but we have only a limited sample of them well understood enough from an asteroseismological point of view to provide feedback on the current evolutionary models. Our study adds one special case to this sample, with more observational constraints than for most of these stars. Aims. Our goal is to analyse and interpret the pulsational behaviour of the B3 IV star HD 43317 using the CoRoT light curve along with the ground-based spectroscopy gathered by the Harps instrument. This way we continue our efforts to map the Beta Cep and SPB instability strips. Methods. We used different techniques to reveal the abundances and fundamental stellar parameters from the newly-obtained high-resolution spectra. We used various time-series analysis tools to explore the nature of variations present in the light curve. We calculated the moments and used the pixel-by-pixel method to look for line profile variations in the high-resolution spectra. Results. We find th...

  5. The minimal genus problem in rational surfaces CP2#n-CP2

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xu'an; GAO Hongzhu; QIU Huaidong

    2006-01-01

    There are three key ingredients in the study of the minimal genus problem for rational surfaces CP2#n-CP2: the generalized adjunction formula, the action of the orthogonal group of the Lorentz space and the geometric construction. In this paper, we prove the uniqueness of the standard form (see Definition 1.1 and Theorem 1.1) of a 2-dimensional homology class under the action of the subgroup of the Lorentz orthogonal group that is realized by the diffeomorphisms of CP2#n-CP2. Using the geometric construction, we determine the minimal genera of some classes (see Theorem 1.2).

  6. A novel MeCP2 acetylation site regulates interaction with ATRX and HDAC1.

    Science.gov (United States)

    Pandey, Somnath; Simmons, Glenn E; Malyarchuk, Svitlana; Calhoun, Tara N; Pruitt, Kevin

    2015-09-01

    Methyl-CpG-binding protein-2 (MeCP2) regulates gene expression by recruiting SWI/SNF DNA helicase/ATPase (ATRX) and Histone Deacetylase-1 (HDAC1) to methylated gene regions and modulates heterochromatin association by interacting with Heterochromatin protein-1. As MeCP2 contributes to tumor suppressor gene silencing and its mutation causes Rett Syndrome, we investigated how novel post-translational-modification contributes to its function. Herein we report that upon pharmacological inhibition of SIRT1 in RKO colon and MCF-7 breast cancer cells, endogenous MeCP2 is acetylated at sites critical for binding to DNA and transcriptional regulators. We created an acetylation mimetic mutation in MeCP2 and found it to possess decreased binding to ATRX and HDAC1. Conditions inducing MeCP2 acetylation do not alter its promoter occupancy at a subset of target genes analyzed, but do cause decreased binding to ATRX and HDAC1. We also report here that a specific inhibitor of SIRT1, IV, can be used to selectively decrease H3K27me3 repressive marks on a subset of repressed target gene promoters analyzed. Lastly, we show that RKO cells over-expressing MeCP2 mutant show reduced proliferation compared to those over-expressing MeCP2-wildtype. Our study demonstrates the importance of acetylated lysine residues and suggests their key role in regulating MeCP2 function and its ability to bind transcriptional regulators.

  7. An abundance study of the solar-analogue, CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

    CERN Document Server

    Morel, T; Poretti, E; Barban, C; Boumier, P

    2013-01-01

    We present a detailed abundance study based on spectroscopic data obtained with HARPS of two solar-analogue, main targets for the asteroseismology programme of the CoRoT satellite: HD 42618 and HD 43587. The atmospheric parameters and chemical composition are accurately determined through a fully differential analysis with respect to the Sun observed with the same instrumental set-up. Several sources of systematic errors largely cancel out with such an approach, allowing us to narrow down the 1-sigma error bars to typically 20 K in effective temperature, 0.04 dex in surface gravity and less than 0.05 dex in the elemental abundances. Although HD 42618 fulfills many requirements for being classified as a solar twin, its slight deficiency in metals and possibly younger age indicate that, strictly speaking, it does not belong to this class of objects. On the other hand, HD 43587 is slightly more massive and evolved. In addition, marked differences are found in the amount of lithium present in the photospheres of ...

  8. Ground-based observations of the beta Cephei CoRoT main target HD 180642: abundance analysis and mode identification

    CERN Document Server

    Briquet, M; Morel, T; Aerts, C; De Cat, P; Mathias, P; Lefever, K; Miglio, A; Poretti, E; Martin-Ruiz, S; Paparo, M; Rainer, M; Carrier, F; Gutiérrez-Soto, J; Valtier, J C; Benko, J M; Bognár, Z; Niemczura, E; Amado, P J; Suárez, J C; Moya, A; Rodriguez-Lopez, C; Garrido, R

    2009-01-01

    The known beta Cephei star HD 180642 was observed by the CoRoT satellite in 2007. From the very high-precision light curve, its pulsation frequency spectrum could be derived for the first time (Degroote and collaborators). In this paper, we obtain additional constraints for forthcoming asteroseismic modeling of the target. Our results are based on both extensive ground-based multicolour photometry and high-resolution spectroscopy. We determine T_eff = 24 500+-1000 K and log g = 3.45+-0.15 dex from spectroscopy. The derived chemical abundances are consistent with those for B stars in the solar neighbourhood, except for a mild nitrogen excess. A metallicity Z = 0.0099+-0.0016 is obtained. Three modes are detected in photometry. The degree l is unambiguously identified for two of them: l = 0 and l = 3 for the frequencies 5.48694 1/d and 0.30818 1/d, respectively. The radial mode is non-linear and highly dominant with an amplitude in the U-filter about 15 times larger than the strongest of the other modes. For th...

  9. Abundance analysis of prime B-type targets for asteroseismology II. B6--B9.5 stars in the field of view of the CoRoT

    CERN Document Server

    Niemczura, E; Aerts, C

    2009-01-01

    The CoRoT satellite is collecting precise time-resolved photometry for tens of asteroseismology targets. To ensure a correct interpretation of the CoRoT data, the atmospheric parameters, chemical compositions, and rotational velocities of the stars must be determined. The main goal of the ground-based seismology support program for the CoRoT mission was to obtain photometric and spectroscopic data for stars in the fields monitored by the satellite. These ground-based observations were collected in the GAUDI archive. High-resolution spectra of more than 200 B-type stars are available in this database, and about 45% of them is analysed here. To derive the effective temperature of the stars, we used photometric indices. Surface gravities were obtained by comparing observed and theoretical Balmer line profiles. To determine the chemical abundances and rotational velocities, we used a spectrum synthesis method, which consisted of comparing the observed spectrum with theoretical ones based on the assumption of LTE....

  10. Total synthesis of (-)-CP2-disorazole C1.

    Science.gov (United States)

    Hopkins, Chad D; Schmitz, John C; Chu, Edward; Wipf, Peter

    2011-08-05

    The total synthesis of a bis-cyclopropane analog of the antimitotic natural product (-)-disorazole C(1) was accomplished in 23 steps and 1.1% overall yield. A vinyl cyclopropane cross-metathesis reaction generated a key (E)-alkene segment of the target molecule. IC(50) determinations of (-)-CP(2)-disorazole C(1) in human colon cancer cell lines indicated low nanomolar cytotoxic properties. Accordingly, this synthetic bioisostere represents the first biologically active disorazole analog not containing a conjugated diene or polyene substructure element.

  11. Transcription factor CP2 is involved in activating mBMP4 in mouse mesenchymal stem cells.

    Science.gov (United States)

    Kang, Ho Chul; Chae, Ji Hyung; Kim, Beom Sue; Han, Su Youne; Kim, Sung-Hyun; Auh, Chung-Kyoon; Yang, Sung-Il; Kim, Chul Geun

    2004-06-30

    CP2 is a member of a family of transcription factors that regulate genes involved in events from early development to terminal differentiation. In an effort to understand how it selects its target genes we carried out a database search, and located several CP2 binding motifs in the promoter region of bone morphogenetic protein-4 (BMP4). BMP4 is a key regulator of cell fate and body patterning throughout development. For the CP2 binding motifs in BMP4 promoter region to be relevant in vivo, CP2 and BMP4 should be expressed together. We found that CP2b and CP2c, two potent transcriptional activators, are expressed in a manner similar to BMP4 during osteoblast differentiation of C3H10T1/2 cells. In in vitro assays, the CP2 proteins bound to two CP2 binding motifs (-715 to -676 and -147 to -118) in the BMP4 promoter, and luciferase reporter assays indicated that this binding was essential for transcription of BMP4 during osteoblast differentiation. Taken together, our data indicate that CP2b and CP2c play important roles during bone development by activating BMP4 transcription.

  12. Circadian cycle-dependent MeCP2 and brain chromatin changes.

    Science.gov (United States)

    Martínez de Paz, Alexia; Sanchez-Mut, Jose Vicente; Samitier-Martí, Mireia; Petazzi, Paolo; Sáez, Mauricio; Szczesna, Karolina; Huertas, Dori; Esteller, Manel; Ausió, Juan

    2015-01-01

    Methyl CpG binding protein 2 (MeCP2) is a chromosomal protein of the brain, very abundant especially in neurons, where it plays an important role in the regulation of gene expression. Hence it has the potential to be affected by the mammalian circadian cycle. We performed expression analyses of mice brain frontal cortices obtained at different time points and we found that the levels of MeCP2 are altered circadianly, affecting overall organization of brain chromatin and resulting in a circadian-dependent regulation of well-stablished MeCP2 target genes. Furthermore, this data suggests that alterations of MeCP2 can be responsible for the sleeping disorders arising from pathological stages, such as in autism and Rett syndrome.

  13. Europe looks forward to COROT launch

    Science.gov (United States)

    2006-12-01

    potential European partners was issued in 1999. CNES gave the green light to build the spacecraft in 2000 and is now leading the mission. Its international partners are ESA, Austria, Belgium, Germany, Spain and Brazil. CNES is responsible for the overall system and for the launch contract with Franco-Russian company Starsem, which is providing the Soyuz launch service. The contributions of the other international partners range from the provision of hardware items to ground stations, complementary ground-based observation of targets to be studied by COROT and analysis of the scientific data to come. ESA is playing a crucial role in the mission. It has contributed the optics for the telescope positioned at the heart of the spacecraft and has carried out payload testing. The telescope’s baffle was developed by a team at ESA’s technical centre ESTEC. ESA has also provided the onboard data processing units. And under this truly collaborative effort, a number of scientists from various European countries - Denmark, Switzerland, the United Kingdom and Portugal - have been selected as Co-Investigators following open competition. As a result of ESA’s participation, scientists from its Member States will also be given access to COROT data.

  14. Planetary transit candidates in COROT-IRa01 field

    CERN Document Server

    Carpano, S; Alonso, R; Barge, P; Aigrain, S; Almenara, J -M; Bordé, P; Bouchy, F; Carone, L; Deeg, H J; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Fressin, F; Fridlund, M; Gondoin, P; Guillot, T; Hatzes, A; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Moutou, C; Ofir, A; Ollivier, M; Pacheco, E J; Pátzold, M; Pont, F; Queloz, D; Rauer, H; Régulo, C; Renner, S; Rouan, D; Samuel, B; Schneider, J; Wuchterl, G

    2009-01-01

    Context: CoRoT is a pioneering space mission devoted to the analysis of stellar variability and the photometric detection of extrasolar planets. Aims: We present the list of planetary transit candidates detected in the first field observed by CoRoT, IRa01, the initial run toward the Galactic anticenter, which lasted for 60 days. Methods: We analysed 3898 sources in the coloured bands and 5974 in the monochromatic band. Instrumental noise and stellar variability were taken into account using detrending tools before applying various transit search algorithms. Results: Fifty sources were classified as planetary transit candidates and the most reliable 40 detections were declared targets for follow-up ground-based observations. Two of these targets have so far been confirmed as planets, COROT-1b and COROT-4b, for which a complete characterization and specific studies were performed.

  15. Rett综合征相关基因MeCP2敲除大鼠模型的构建及分析%Generation and analysis of the Rett syndrome-associated MeCP2-null rat model

    Institute of Scientific and Technical Information of China (English)

    翟伟; 王晓英; 匡世焕; 胡克平; 胡宏秀; 乐亮; 庄峰峰; 王克柱; 赵英; 王凯; 刘新民; 孙迪安

    2016-01-01

    MeCP2 mutations are associated with the Rett syndrome (RTT). Currently, there is an urgent need for new animal models for RTT as the existing MeCP2 knockout mouse models fail to fully mimic the pathogenesis and symptoms of RTT patients. In order to investigate the role of MeCP2 in brain development and RTT pathogenesis, we aimed to set up the MeCP2-null rat model using the CRISPR/Cas9 technology. Firstly we constructed the MeCP2 targeting vector and then microinjected Cas9 mRNA and sgRNA mixtures into fertilized ova of SD rats. The sgRNA was designed to target the exon 2 of MeCP2. Next, knockout rats were confirmed using DNA sequencing and Western blotting. Lastly, phenotypes including growth and behaviors of MeCP2 knockout rats were analyzed. The results indicated that the MeCP2 knockout rats showed body weight loss, anxiety tendency and cognitive deficits. The MeCP2-null rat model established in this study recapitulates the major symptoms of RTT patients and provides an alternative tool for future studies of MeCP2 functions.%MeCP2(Methyl CpG binding protein 2)基因突变可导致Rett综合征(Rett syndrome, RTT)。目前已报道的MeCP2敲除小鼠表型与RTT病人症状存在显著差异。为探索MeCP2在脑发育中的作用及其导致RTT的机制,本研究利用CRISPR/Cas9技术构建了MeCP2基因敲除大鼠模型。通过构建靶向敲除MeCP2基因的载体,体外将Cas9 mRNA和sgRNA显微注射到SD大鼠受精卵中,在MeCP2基因exon2中造成移码突变,从而获得MeCP2基因敲除大鼠。利用测序和Western blotting方法鉴定MeCP2敲除大鼠,并对其表型和行为学特征进行分析,发现MeCP2敲除大鼠体重降低,存在焦虑倾向和认知缺陷。本研究成功构建了MeCP2基因敲除大鼠模型,其表型类似人类RTT患者的症状,为后续MeCP2功能研究提供了更好的动物模型。

  16. CP2 gene as a useful viability marker for Cryptosporidium parvum.

    Science.gov (United States)

    Lee, Soo-Ung; Joung, Migyo; Ahn, Myoung-Hee; Huh, Sun; Song, Hyunje; Park, Woo-Yoon; Yu, Jae-Ran

    2008-02-01

    The validity of the CP2 gene of Cryptosporidium parvum as a viability marker was evaluated using absolute quantitative real-time polymerase chain reaction (qPCR) assays. Total ribonucleic acid (RNA) was isolated from live and heat-killed C. parvum oocysts, and complementary deoxyribonucleic acid was synthesized and used as a template. The most accurate number of viable C. parvum oocysts was predicted when the CP2 gene was used as a target gene. The lower detection limit of the CP2 gene was ten oocysts, which was the most sensitive among examined target genes. With heat shock induction, only hsp70 messenger RNA (mRNA) was induced, and the predicted viable oocyst number was increased by heat shock for this marker. The CP2, hsp70, Cryptosporidium oocyst wall protein, and beta-tubulin mRNAs were not detected in heat-killed oocysts, but the 18S ribosomal ribonucleic acid (rRNA) showed heat stability until 48 h after heat killing. Although the 18S rRNA demonstrated the fastest response in crossing point (CP) value among the examined primer sets in qPCR, overestimation of viable oocysts was noted in the analysis with this gene. In conclusion, the CP2 gene was identified as the most sensitive, reliable, and accurate candidate of a viability marker of C. parvum by qPCR evaluation.

  17. CoRoT data reduction by example

    Science.gov (United States)

    Weingrill, J.

    2015-02-01

    Data reduction techniques published so far for the CoRoT N2 data product were targeted primarily on the detection of extrasolar planets. Since the whole dataset has been released, specific algorithms are required to process the lightcurves from CoRoT correctly. Though only unflagged datapoints must be chosen for scientific processing, some flags might be reconsidered. The reduction of data along with improving the signal-to-noise ratio can be achieved by applying a one dimensional drizzle algorithm. Gaps can be filled by linear interpolated data without harming the frequency spectrum. Magnitudes derived from the CoRoT color channels might be used to derive additional information about the targets. Depending on the needs, various filters in the frequency domain remove either the red noise background or high frequency noise. The autocorrelation function or the least squares periodogram are appropriate methods to identify periodic signals. The methods described here are not strictly limited to CoRoT data but may also be applied on Kepler data or the upcoming PLATO mission. The CoRoT space mission, launched on 2006 December 27, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain.

  18. MeCP2-Related Diseases and Animal Models

    Directory of Open Access Journals (Sweden)

    Chinelo D. Ezeonwuka

    2014-01-01

    Full Text Available The role of epigenetics in human disease has become an area of increased research interest. Collaborative efforts from scientists and clinicians have led to a better understanding of the molecular mechanisms by which epigenetic regulation is involved in the pathogenesis of many human diseases. Several neurological and non-neurological disorders are associated with mutations in genes that encode for epigenetic factors. One of the most studied proteins that impacts human disease and is associated with deregulation of epigenetic processes is Methyl CpG binding protein 2 (MeCP2. MeCP2 is an epigenetic regulator that modulates gene expression by translating epigenetic DNA methylation marks into appropriate cellular responses. In order to highlight the importance of epigenetics to development and disease, we will discuss how MeCP2 emerges as a key epigenetic player in human neurodevelopmental, neurological, and non-neurological disorders. We will review our current knowledge on MeCP2-related diseases, including Rett Syndrome, Angelman Syndrome, Fetal Alcohol Spectrum Disorder, Hirschsprung disease, and Cancer. Additionally, we will briefly discuss about the existing MeCP2 animal models that have been generated for a better understanding of how MeCP2 impacts certain human diseases.

  19. MeCP2-Related Diseases and Animal Models

    Science.gov (United States)

    Ezeonwuka, Chinelo D.; Rastegar, Mojgan

    2017-01-01

    The role of epigenetics in human disease has become an area of increased research interest. Collaborative efforts from scientists and clinicians have led to a better understanding of the molecular mechanisms by which epigenetic regulation is involved in the pathogenesis of many human diseases. Several neurological and non-neurological disorders are associated with mutations in genes that encode for epigenetic factors. One of the most studied proteins that impacts human disease and is associated with deregulation of epigenetic processes is Methyl CpG binding protein 2 (MeCP2). MeCP2 is an epigenetic regulator that modulates gene expression by translating epigenetic DNA methylation marks into appropriate cellular responses. In order to highlight the importance of epigenetics to development and disease, we will discuss how MeCP2 emerges as a key epigenetic player in human neurodevelopmental, neurological, and non-neurological disorders. We will review our current knowledge on MeCP2-related diseases, including Rett Syndrome, Angelman Syndrome, Fetal Alcohol Spectrum Disorder, Hirschsprung disease, and Cancer. Additionally, we will briefly discuss about the existing MeCP2 animal models that have been generated for a better understanding of how MeCP2 impacts certain human diseases.

  20. Accretion discs trapped near corotation

    OpenAIRE

    D'Angelo, C.R.; Spruit, H.C.

    2012-01-01

    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states over a wide range of parameter space. We find two distinct regions of instability: one related to the buildup and release of mass in the disc outside corotation, and the other to mass storage with...

  1. 有理曲面(CP2#n-CP2)中的极小亏格问题

    Institute of Scientific and Technical Information of China (English)

    赵旭安; 高红铸; 邱怀东

    2006-01-01

    在有理曲面(CP2#n-CP2)的极小亏格问题研究中有3个关键因素:广义附加公式,Lorentz空间上的正交群作用以及几何构造.本文证明了CP2#n-CP2的2维同调类在微分同胚群作用下的标准型的唯一性(见定义1.1和定理1.1).利用几何构造,确定了某些同调类的极小亏格(见定理1.2).

  2. MeCP2与神经发育性疾病%MeCP2 and neurodevelopmental disorders

    Institute of Scientific and Technical Information of China (English)

    何艳琴; 公晓红; 王红艳; 杨章民

    2012-01-01

    As a transcription repressor, methyi-CpG binding protein 2 (MeCP2) comprises two functional domains: methyl DNA binding domain and a transcription repression domain. MeCP2, which acts as a multifunctional nuclear protein in several cellular aspects(such as the chromatin remodelling, transcription activation, regulation of RNA splicing and so on), may plays important roles in the process of neural development. Recent researches show that MeCP2 gene mutation is implicated in neurodevelopmental disorder, including Ren syndrome and autism. So MeCP2 gene has become a hotspot in the study of the relationship between the genotype and the human neurodevelopmental diseases. This review summarizes the latest advances on MeCP2 in Rett syndrome, autism and drug addiction.%作为一种转录抑制因子,甲基化CpG结合蛋白2(MeCP2)含有结合甲基化DNA和转录抑制两个特征性的结构域,具有调节转录激活、调节染色体构象、参与RNA剪切等多种功能,在神经发育过程中起着重要的作用.近来的研究表明,MeCP2基因突变与Rett综合征、孤独症等多种神经发育性疾病相关,已成为研究基因型与人类神经发育性疾病关系的一个热点.就MeCP2在Rett综合征、孤独症及药物成瘾方面的进展作一综述.

  3. Accretion discs trapped near corotation

    NARCIS (Netherlands)

    D'Angelo, C.R.; Spruit, H.C.

    2012-01-01

    We show that discs accreting on to the magnetosphere of a rotating star can end up in a trapped state, in which the inner edge of the disc stays near the corotation radius, even at low and varying accretion rates. The accretion in these trapped states can be steady or cyclic; we explore these states

  4. Simple but Stronger UO, Double but Weaker UNMe Bonds: The Tale Told by Cp2UO and Cp2UNR

    Energy Technology Data Exchange (ETDEWEB)

    LPCNO, CNRS-UPS-INSA, INSA Toulouse; Institut Charles Gerhardt, CNRS, Universite Montpellier; Laboratoire de Chimie et Physique Quantiques, CNRS, IRSAMC, Universite Paul Sabatier; Andersen, Richard; Barros, Noemi; Maynau, Daniel; Maron, Laurent; Eisenstein, Odile; Zi, Guofu; Andersen, Richard

    2007-06-27

    The free energies of reaction and the activation energies are calculated, with DFT (B3PW91) and small RECP (relativistic core potential) for uranium, for the reaction of Cp2UNMe and Cp2UO with MeCCMe and H3Si-Cl that yields the corresponding addition products. CAS(2,7) and DFT calculations on Cp2UO and Cp2UNMe give similar results, which validates the use of DFT calculations in these cases. The calculated results mirror the experimental reaction of [1,2,4-(CMe3)3C5H2]2UNMe with dimethylacetylene and [1,2,4-(CMe3)3C5H2]2UO with Me3SiCl. The net reactions are controlled by the change in free energy between the products and reactants, not by the activation energies, and therefore by the nature of the UO and UNMe bonds in the initial and final states. A NBO analysis indicates that the U-O interaction in Cp2UO is composed of a single U-O bond with three lone pairs of electrons localized on oxygen, leading to a polarized U-O fragment. In contrast, the U-NMe interaction in Cp2UNMe is composed of a and component and a lone pairof electrons localized on the nitrogen, resulting in a less polarized UNMe fragment, in accord with the lower electronegativity of NMe relative to O. The strongly polarized U(+)-O(-) bond is calculated to be about 70 kcal mol-1 stronger than the less polarized U=NMe bond.

  5. Erythroid cell-specific alpha-globin gene regulation by the CP2 transcription factor family.

    Science.gov (United States)

    Kang, Ho Chul; Chae, Ji Hyung; Lee, Yeon Ho; Park, Mi-Ae; Shin, June Ho; Kim, Sung-Hyun; Ye, Sang-Kyu; Cho, Yoon Shin; Fiering, Steven; Kim, Chul Geun

    2005-07-01

    We previously demonstrated that ubiquitously expressed CP2c exerts potent erythroid-specific transactivation of alpha-globin through an unknown mechanism. This mechanism is reported here to involve specific CP2 splice variants and protein inhibitor of activated STAT1 (PIAS1). We identify a novel murine splice isoform of CP2, CP2b, which is identical to CP2a except that it has an additional 36 amino acids encoded by an extra exon. CP2b has an erythroid cell-specific transcriptional activation domain, which requires the extra exon and can form heteromeric complexes with other CP2 isoforms, but lacks the DNA binding activity found in CP2a and CP2c. Transcriptional activation of alpha-globin occurred following dimerization between CP2b and CP2c in erythroid K562 and MEL cells, but this dimerization did not activate the alpha-globin promoter in nonerythroid 293T cells, indicating that an additional erythroid factor is missing in 293T cells. PIAS1 was confirmed as a CP2 binding protein by the yeast two-hybrid screen, and expression of CP2b, CP2c, and PIAS1 in 293T cell induced alpha-globin promoter activation. These results show that ubiquitously expressed CP2b exerts potent erythroid cell-specific alpha-globin gene expression by complexing with CP2c and PIAS1.

  6. Erythroid Cell-Specific α-Globin Gene Regulation by the CP2 Transcription Factor Family

    Science.gov (United States)

    Kang, Ho Chul; Chae, Ji Hyung; Lee, Yeon Ho; Park, Mi-Ae; Shin, June Ho; Kim, Sung-Hyun; Ye, Sang-Kyu; Cho, Yoon Shin; Fiering, Steven; Kim, Chul Geun

    2005-01-01

    We previously demonstrated that ubiquitously expressed CP2c exerts potent erythroid-specific transactivation of α-globin through an unknown mechanism. This mechanism is reported here to involve specific CP2 splice variants and protein inhibitor of activated STAT1 (PIAS1). We identify a novel murine splice isoform of CP2, CP2b, which is identical to CP2a except that it has an additional 36 amino acids encoded by an extra exon. CP2b has an erythroid cell-specific transcriptional activation domain, which requires the extra exon and can form heteromeric complexes with other CP2 isoforms, but lacks the DNA binding activity found in CP2a and CP2c. Transcriptional activation of α-globin occurred following dimerization between CP2b and CP2c in erythroid K562 and MEL cells, but this dimerization did not activate the α-globin promoter in nonerythroid 293T cells, indicating that an additional erythroid factor is missing in 293T cells. PIAS1 was confirmed as a CP2 binding protein by the yeast two-hybrid screen, and expression of CP2b, CP2c, and PIAS1 in 293T cell induced α-globin promoter activation. These results show that ubiquitously expressed CP2b exerts potent erythroid cell-specific α-globin gene expression by complexing with CP2c and PIAS1. PMID:15988015

  7. Pre-discovery observations of CoRoT-1b and CoRoT-2b with the BEST survey

    CERN Document Server

    Rauer, H; Kabath, P; Hedelt, P; Boër, M; Carone, L; Csizmadia, Sz; Eigmueller, P; Paris, P v; Renner, S; Tournois, G; Titz, R; Voss, H

    2009-01-01

    The BEST wide-angle telescope installed at the Observatoire de Haute-Provence and operated in remote control from Berlin by the Institut fuer Planetenforschung, DLR, has observed the CoRoT target fields prior to the mission. The resulting archive of stellar photometric lightcurves is used to search for deep transit events announced during CoRoT's alarm-mode to aid in fast photometric confirmation of these events. The "initial run" field of CoRoT (IRa01) has been observed with BEST in November and December 2006 for 12 nights. The first "long run" field (LRc01) was observed from June to September 2005 for 35 nights. After standard CCD data reduction, aperture photometry has been performed using the ISIS image subtraction method. About 30,000 lightcurves were obtained in each field. Transits of the first detected planets by the CoRoT mission, CoRoT-1b and CoRoT-2b, were found in archived data of the BEST survey and their lightcurves are presented here. Such detections provide useful information at the early stag...

  8. The protocadherins, PCDHB1 and PCDH7, are regulated by MeCP2 in neuronal cells and brain tissues: implication for pathogenesis of Rett syndrome

    Directory of Open Access Journals (Sweden)

    Nakagawa Takayuki

    2011-08-01

    Full Text Available Abstract Background Rett syndrome is a neurodevelopmental and autistic disease caused by mutations of Methyl-CpG-binding protein 2 (MECP2 gene. MeCP2 protein is mainly expressed in neurons and binds to methylated gene promoters to suppress their expression, indicating that Rett syndrome is caused by the deregulation of target genes in neurons. However, it is likely that there are more unidentified neuronal MeCP2-targets associated with the neurological features of RTT. Results Using a genome-microarray approach, we found 22 genomic regions that contain sites potentially regulated by MeCP2 based on the features of MeCP2 binding, DNA methylation, and repressive histone modification in human cell lines. Within these regions, Chromatin immunoprecipitation (ChIP analysis revealed that MeCP2 binds to the upstream regions of the protocadherin genes PCDHB1 and PCDH7 in human neuroblastoma SH-SY5Y cells. PCDHB1 and PCDH7 promoter activities were down-regulated by MeCP2, but not by MBD-deleted MeCP2. These gene expression were up-regulated following MeCP2 reduction with siRNA in SH-SY5Y cells and in the brains of Mecp2-null mice. Furthermore, PCDHB1 was up-regulated in postmortem brains from Rett syndrome patients. Conclusions We identified MeCP2 target genes that encode neuronal adhesion molecules using ChIP-on-BAC array approach. Since these protocadherin genes are generally essential for brain development, aberrant regulation of these molecules may contribute to the pathogenesis of the neurological features observed in Rett syndrome.

  9. Revisiting the Corotation Electric Field

    Science.gov (United States)

    Rothwell, P. L.

    2001-05-01

    The rotation of the Earth's dipole magnetic field produces a corotation electric field in the nonrotating frame of reference. A quick calculation implies that this field might arise from the relative motion of an observer in the nonrotating frame and the motion of rotating magnetic field lines. However, upon applying Faraday's Law one finds that total time rate of change of the magnetic field as seen in the nonrotating frame is zero due to the azimuthal symmetry of the dipole. Therefore, classical EM theory(1) predicts a zero corotation electric field in the nonrotating frame for a vacuum. This conundrum has been traditionally treated in the following manner(2,3). 1) Start with a vacuum state with no conductors and plasma present. The transformation between E (the electric field in the nonrotating frame) and E' (the electric field in the rotating frame)implies that in the rotating frame E' is nonzero while E = 0. 2) In the presence of a thin conducting spherical shell (the ionosphere) polarization charges form in the shell due to the magnetic force on the electrons. A polarization electric field Ep is created such that in the idealized case the shell has a uniform electric potential. This Ep has a component along the magnetic field lines outside the shell. 3) Plasma will polarize along B, thus canceling the parallel component of Ep which allows the potential on the shell to be mapped along the magnetic field lines setting E' = 0. From the transformation equation E is now nonzero. This is the electric field required in the nonrotating frame for the plasma to corotate with the dipole. The presence of the corotation electric field is not a local result, but a nonlocal effect that requires the presence of an ionosphere and a conducting plasma. (1) W.K.H. Panofsky and M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, 1956. (2) H. Alfven and C.-G. Falthammar, Cosmical Electrodynamics, 2nd ed., Oxford Press, 1963. (3) E.W.Hones and J.E.Bergeson, J. Geophys

  10. Cloning, expression and processing of the CP2 neuropeptide precursor of Aplysia.

    Science.gov (United States)

    Vilim, F S; Alexeeva, V; Moroz, L L; Li, L; Moroz, T P; Sweedler, J V; Weiss, K R

    2001-12-01

    The cDNA sequence encoding the CP2 neuropeptide precursor is identified and encodes a single copy of the neuropeptide that is flanked by appropriate processing sites. The distribution of the CP2 precursor mRNA is described and matches the CP2-like immunoreactivity described previously. Single cell RT-PCR independently confirms the presence of CP2 precursor mRNA in selected neurons. MALDI-TOF MS is used to identify additional peptides derived from the CP2 precursor in neuronal somata and nerves, suggesting that the CP2 precursor may give rise to additional bioactive neuropeptides.

  11. Elevated IKKα accelerates the differentiation of human neuronal progenitor cells and induces MeCP2-dependent BDNF expression.

    Directory of Open Access Journals (Sweden)

    Ali Khoshnan

    Full Text Available The IκB kinase α (IKKα is implicated in the differentiation of epithelial and immune cells. We examined whether IKKα also plays a role in the differentiation and maturation of embryonic human neuronal progenitor cells (NPCs. We find that expression of an extra copy of IKKα (IKKα+ blocks self-renewal and accelerates the differentiation of NPCs. This coincides with reduced expression of the Repressor Element Silencing Transcription Factor/Neuron-Restrictive Silencing Factor (REST/NRSF, which is a prominent inhibitor of neurogenesis, and subsequent induction of the pro-differentiation non-coding RNA, miR-124a. However, the effects of IKKα on REST/NRSF and miR-124a expression are likely to be indirect. IKKα+ neurons display extensive neurite outgrowth and accumulate protein markers of neuronal maturation such as SCG10/stathmin-2, postsynaptic density 95 (PSD95, syntaxin, and methyl-CpG binding protein 2 (MeCP2. Interestingly, IKKα associates with MeCP2 in the nuclei of human neurons and can phosphorylate MeCP2 in vitro. Using chromatin immunoprecipitation assays, we find that IKKα is recruited to the exon-IV brain-derived neurotrophic factor (BDNF promoter, which is a well-characterized target of MeCP2 activity. Moreover, IKKα induces the transcription of BDNF and knockdown expression of MeCP2 interferes with this event. These studies highlight a role for IKKα in accelerating the differentiation of human NPCs and identify IKKα as a potential regulator of MeCP2 function and BDNF expression.

  12. MeCP2 binds to non-CG methylated DNA as neurons mature, influencing transcription and the timing of onset for Rett syndrome.

    Science.gov (United States)

    Chen, Lin; Chen, Kaifu; Lavery, Laura A; Baker, Steven Andrew; Shaw, Chad A; Li, Wei; Zoghbi, Huda Y

    2015-04-28

    Epigenetic mechanisms, such as DNA methylation, regulate transcriptional programs to afford the genome flexibility in responding to developmental and environmental cues in health and disease. A prime example involving epigenetic dysfunction is the postnatal neurodevelopmental disorder Rett syndrome (RTT), which is caused by mutations in the gene encoding methyl-CpG binding protein 2 (MeCP2). Despite decades of research, it remains unclear how MeCP2 regulates transcription or why RTT features appear 6-18 months after birth. Here we report integrated analyses of genomic binding of MeCP2, gene-expression data, and patterns of DNA methylation. In addition to the expected high-affinity binding to methylated cytosine in the CG context (mCG), we find a distinct epigenetic pattern of substantial MeCP2 binding to methylated cytosine in the non-CG context (mCH, where H = A, C, or T) in the adult brain. Unexpectedly, we discovered that genes that acquire elevated mCH after birth become preferentially misregulated in mouse models of MeCP2 disorders, suggesting that MeCP2 binding at mCH loci is key for regulating neuronal gene expression in vivo. This pattern is unique to the maturing and adult nervous system, as it requires the increase in mCH after birth to guide differential MeCP2 binding among mCG, mCH, and nonmethylated DNA elements. Notably, MeCP2 binds mCH with higher affinity than nonmethylated identical DNA sequences to influence the level of Bdnf, a gene implicated in the pathophysiology of RTT. This study thus provides insight into the molecular mechanism governing MeCP2 targeting and sheds light on the delayed onset of RTT symptoms.

  13. Transiting exoplanets from the CoRoT space mission: VII. The "hot-Jupiter"-type planet CoRoT-5b

    CERN Document Server

    Rauer, H; Csizmadia, Sz; Deleuil, M; Alonso, R; Aigrain, S; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Borde, P; Bouchy, F; Bruntt, H; Cabrera, J; Carone, L; Carpano, S; De la Reza, R; Deeg, H J; Dvorak, R; Erikson, A; Fridlund, M; Gandolfi, D; Gillon, M; Guillot, T; Günther, E; Hatzes, A; Hébrard, G; Kabath, P; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Paetzold, M; Pont, F; Rabus, M; Renner, S; Rouan, D; Shporer, A; Samuel, B; Schneider, J; Triaud, A H M J; Wuchterl, G

    2009-01-01

    Aims. The CoRoT space mission continues to photometrically monitor about 12 000 stars in its field-of-view for a series of target fields to search for transiting extrasolar planets ever since 2007. Deep transit signals can be detected quickly in the "alarm-mode" in parallel to the ongoing target field monitoring. CoRoT's first planets have been detected in this mode. Methods. The CoRoT raw lightcurves are filtered for orbital residuals, outliers, and low-frequency stellar signals. The phase folded lightcurve is used to fit the transit signal and derive the main planetary parameters. Radial velocity follow-up observations were initiated to secure the detection and to derive the planet mass. Results. We report the detection of CoRoT-5b, detected during observations of the LRa01 field, the first long-duration field in the galactic anticenter direction. CoRoT-5b is a "hot Jupiter-type" planet with a radius of 1.388(+0.046, -0.047) R_Jup, a mass of 0.467(+0.047, -0.024) M_Jup, and therefore, a mean density of 0.21...

  14. Rett Syndrome Mutant Neural Cells Lacks MeCP2 Immunoreactive Bands.

    Directory of Open Access Journals (Sweden)

    Carlos Bueno

    Full Text Available Dysfunctions of MeCP2 protein lead to various neurological disorders such as Rett syndrome and Autism. The exact functions of MeCP2 protein is still far from clear. At a molecular level, there exist contradictory data. MeCP2 protein is considered a single immunoreactive band around 75 kDa by western-blot analysis but several reports have revealed the existence of multiple MeCP2 immunoreactive bands above and below the level where MeCP2 is expected. MeCP2 immunoreactive bands have been interpreted in different ways. Some researchers suggest that multiple MeCP2 immunoreactive bands are unidentified proteins that cross-react with the MeCP2 antibody or degradation product of MeCP2, while others suggest that MeCP2 post-transcriptional processing generates multiple molecular forms linked to cell signaling, but so far they have not been properly analyzed in relation to Rett syndrome experimental models. The purpose of this study is to advance understanding of multiple MeCP2 immunoreactive bands in control neural cells and p.T158M MeCP2e1 mutant cells. We have generated stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Application of N- and C- terminal MeCP2 antibodies, and also, RFP antibody minimized concerns about nonspecific cross-reactivity, since they react with the same antigen at different epitopes. We report the existence of multiple MeCP2 immunoreactive bands in control cells, stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Also, MeCP2 immunoreactive bands differences were found between wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Slower migration phosphorylated band around 70kDa disappeared in p.T158M MeCP2e1-RFP mutant expressing cells. These data suggest that threonine 158 could represent an important phosphorylation site potentially involved in protein function. Our results clearly indicate that MeCP2 antibodies have no cross-reactivity with similar epitopes on others proteins, supporting the

  15. Rett Syndrome Mutant Neural Cells Lacks MeCP2 Immunoreactive Bands

    Science.gov (United States)

    Bueno, Carlos; Tabares-Seisdedos, Rafael; Moraleda, Jose M.; Martinez, Salvador

    2016-01-01

    Dysfunctions of MeCP2 protein lead to various neurological disorders such as Rett syndrome and Autism. The exact functions of MeCP2 protein is still far from clear. At a molecular level, there exist contradictory data. MeCP2 protein is considered a single immunoreactive band around 75 kDa by western-blot analysis but several reports have revealed the existence of multiple MeCP2 immunoreactive bands above and below the level where MeCP2 is expected. MeCP2 immunoreactive bands have been interpreted in different ways. Some researchers suggest that multiple MeCP2 immunoreactive bands are unidentified proteins that cross-react with the MeCP2 antibody or degradation product of MeCP2, while others suggest that MeCP2 post-transcriptional processing generates multiple molecular forms linked to cell signaling, but so far they have not been properly analyzed in relation to Rett syndrome experimental models. The purpose of this study is to advance understanding of multiple MeCP2 immunoreactive bands in control neural cells and p.T158M MeCP2e1 mutant cells. We have generated stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Application of N- and C- terminal MeCP2 antibodies, and also, RFP antibody minimized concerns about nonspecific cross-reactivity, since they react with the same antigen at different epitopes. We report the existence of multiple MeCP2 immunoreactive bands in control cells, stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Also, MeCP2 immunoreactive bands differences were found between wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Slower migration phosphorylated band around 70kDa disappeared in p.T158M MeCP2e1-RFP mutant expressing cells. These data suggest that threonine 158 could represent an important phosphorylation site potentially involved in protein function. Our results clearly indicate that MeCP2 antibodies have no cross-reactivity with similar epitopes on others proteins, supporting the idea that MeCP2 may

  16. Rett Syndrome Mutant Neural Cells Lacks MeCP2 Immunoreactive Bands.

    Science.gov (United States)

    Bueno, Carlos; Tabares-Seisdedos, Rafael; Moraleda, Jose M; Martinez, Salvador

    2016-01-01

    Dysfunctions of MeCP2 protein lead to various neurological disorders such as Rett syndrome and Autism. The exact functions of MeCP2 protein is still far from clear. At a molecular level, there exist contradictory data. MeCP2 protein is considered a single immunoreactive band around 75 kDa by western-blot analysis but several reports have revealed the existence of multiple MeCP2 immunoreactive bands above and below the level where MeCP2 is expected. MeCP2 immunoreactive bands have been interpreted in different ways. Some researchers suggest that multiple MeCP2 immunoreactive bands are unidentified proteins that cross-react with the MeCP2 antibody or degradation product of MeCP2, while others suggest that MeCP2 post-transcriptional processing generates multiple molecular forms linked to cell signaling, but so far they have not been properly analyzed in relation to Rett syndrome experimental models. The purpose of this study is to advance understanding of multiple MeCP2 immunoreactive bands in control neural cells and p.T158M MeCP2e1 mutant cells. We have generated stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Application of N- and C- terminal MeCP2 antibodies, and also, RFP antibody minimized concerns about nonspecific cross-reactivity, since they react with the same antigen at different epitopes. We report the existence of multiple MeCP2 immunoreactive bands in control cells, stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Also, MeCP2 immunoreactive bands differences were found between wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Slower migration phosphorylated band around 70kDa disappeared in p.T158M MeCP2e1-RFP mutant expressing cells. These data suggest that threonine 158 could represent an important phosphorylation site potentially involved in protein function. Our results clearly indicate that MeCP2 antibodies have no cross-reactivity with similar epitopes on others proteins, supporting the idea that MeCP2 may

  17. VizieR Online Data Catalog: CoRoT observation log (N2-4.4) (CoRoT 2016)

    Science.gov (United States)

    COROT Team

    spots associated with magnetic activity, oblateness induced by a nearby companion star, ... The data of this CoRoT CDS archive correspond to the legacy release V4.4 of CoRoT N2 data. A complete description can be found in the "CoRoTN2versions_30sept2014.pdf" document available on the vizier ftp as well as on project websites listed in the "See also" field below. Other archives provide an access to the CoRoT data at different levels, or to complementary catalogues - the CoRoT IAS archive at idoc-corot.ias.u-psud.fr/ and mirrors of this archive at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoTexoindex.html and at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoTasteroindex.html - archive at https://sipad-corot.cnes.fr/ or at the CoRoT IAS archive, but they require a deep understanding of the instrument and the observation conditions to be scientifically helpful. - Raw data N0 are available upon request at the CoRoT CNES archive. - Complementary data on the CoRoT targets, obtained through ground based complementary observations, can be found in : * EXODAT for the faint star fields at http://cesam.oamp.fr/exodat/quick-access/retrieve-corot-star * GAUDI for the bright star fields at http://sdc.cab.inta-csic.es/gaudi/ (4 data files).

  18. Chiral CP2 skyrmions in three-band superconductors

    Science.gov (United States)

    Garaud, Julien; Carlström, Johan; Babaev, Egor; Speight, Martin

    2013-01-01

    It is shown that under certain conditions, three-component superconductors (and, in particular, three-band systems) allow stable topological defects different from vortices. We demonstrate the existence of these excitations, characterized by a CP2 topological invariant, in models for three-component superconductors with broken time-reversal symmetry. We term these topological defects “chiral GL(3) skyrmions,” where “chiral” refers to the fact that due to broken time-reversal symmetry, these defects come in inequivalent left- and right-handed versions. In certain cases, these objects are energetically cheaper than vortices and should be induced by an applied magnetic field. In other situations, these skyrmions are metastable states, which can be produced by a quench. Observation of these defects can signal broken time-reversal symmetry in three-band superconductors or in Josephson-coupled bilayers of s± and s-wave superconductors.

  19. Identification and characterization of a critical CP2-binding element in the human interleukin-4 promoter.

    Science.gov (United States)

    Casolaro, V; Keane-Myers, A M; Swendeman, S L; Steindler, C; Zhong, F; Sheffery, M; Georas, S N; Ono, S J

    2000-11-24

    Expression of cytokine genes in T cells is thought to result from a complex network of antigen- and mitogen-activated transcriptional regulators. CP2, a factor homologous to Drosophila Elf-1 and previously found to be a critical regulator of several viral and cellular genes in response to developmental signals, is rapidly activated in T helper (Th) cells in response to mitogenic stimulation. Here we show that overexpression of CP2 enhances interleukin (IL)-4 promoter-driven chloramphenicol acetyltransferase expression, while repressing IL-2 promoter activity, in transiently transfected Jurkat cells. A CP2-protected element, partially overlapping the nuclear factor of activated T cell-binding P2 sequence, was required for IL-4 promoter activation in CP2-overexpressing Jurkat cells. This CP2-response element is the site of a cooperative interaction between CP2 and an inducible heteromeric co-factor(s). Mutation of conserved nucleotide contacts within the CP2-response element prevented CP2 binding and significantly reduced constitutive and induced IL-4 promoter activity. Expression of a CP2 mutant lacking the Elf-1-homology region of the DNA-binding domain inhibited IL-4 promoter activity in a dominant negative fashion in transiently transfected Jurkat cells. Moreover, overexpressed CP2 markedly enhanced, while its dominant negative mutant consistently suppressed, expression of the endogenous IL-4 gene in the murine Th2 cell line D10. Taken together, these findings point to CP2 as a critical IL-4 transactivator in Th cells.

  20. Modulation of CP2 family transcriptional activity by CRTR-1 and sumoylation.

    Directory of Open Access Journals (Sweden)

    Sarah To

    Full Text Available CRTR-1 is a member of the CP2 family of transcription factors. Unlike other members of the family which are widely expressed, CRTR-1 expression shows specific spatio-temporal regulation. Gene targeting demonstrates that CRTR-1 plays a central role in the maturation and function of the salivary glands and the kidney. CRTR-1 has also recently been identified as a component of the complex transcriptional network that maintains pluripotency in embryonic stem (ES cells. CRTR-1 was previously shown to be a repressor of transcription. We examine the activity of CRTR-1 in ES and other cells and show that CRTR-1 is generally an activator of transcription and that it modulates the activity of other family members, CP2, NF2d9 and altNF2d9, in a cell specific manner. We also demonstrate that CRTR-1 activity is regulated by sumoylation at a single major site, residue K30. These findings imply that functional redundancy with other family members may mask important roles for CRTR-1 in other tissues, including the blastocyst stage embryo and embryonic stem cells.

  1. Modulation of CP2 family transcriptional activity by CRTR-1 and sumoylation.

    Science.gov (United States)

    To, Sarah; Rodda, Stephen J; Rathjen, Peter D; Keough, Rebecca A

    2010-07-22

    CRTR-1 is a member of the CP2 family of transcription factors. Unlike other members of the family which are widely expressed, CRTR-1 expression shows specific spatio-temporal regulation. Gene targeting demonstrates that CRTR-1 plays a central role in the maturation and function of the salivary glands and the kidney. CRTR-1 has also recently been identified as a component of the complex transcriptional network that maintains pluripotency in embryonic stem (ES) cells. CRTR-1 was previously shown to be a repressor of transcription. We examine the activity of CRTR-1 in ES and other cells and show that CRTR-1 is generally an activator of transcription and that it modulates the activity of other family members, CP2, NF2d9 and altNF2d9, in a cell specific manner. We also demonstrate that CRTR-1 activity is regulated by sumoylation at a single major site, residue K30. These findings imply that functional redundancy with other family members may mask important roles for CRTR-1 in other tissues, including the blastocyst stage embryo and embryonic stem cells.

  2. Influenza A induces dysfunctional immunity and death in MeCP2-overexpressing mice

    Science.gov (United States)

    Cronk, James C.; Herz, Jasmin; Kim, Taeg S.; Louveau, Antoine; Moser, Emily K.; Smirnov, Igor; Tung, Kenneth S.; Braciale, Thomas J.

    2017-01-01

    Loss of function or overexpression of methyl-CpG-binding protein 2 (MeCP2) results in the severe neurodevelopmental disorders Rett syndrome and MeCP2 duplication syndrome, respectively. MeCP2 plays a critical role in neuronal function and the function of cells throughout the body. It has been previously demonstrated that MeCP2 regulates T cell function and macrophage response to multiple stimuli, and that immune-mediated rescue imparts significant benefit in Mecp2-null mice. Unlike Rett syndrome, MeCP2 duplication syndrome results in chronic, severe respiratory infections, which represent a significant cause of patient morbidity and mortality. Here, we demonstrate that MeCP2Tg3 mice, which overexpress MeCP2 at levels 3- to 5-fold higher than normal, are hypersensitive to influenza A/PR/8/34 infection. Prior to death, MeCP2Tg3 mice experienced a host of complications during infection, including neutrophilia, increased cytokine production, excessive corticosterone levels, defective adaptive immunity, and vascular pathology characterized by impaired perfusion and pulmonary hemorrhage. Importantly, we found that radioresistant cells are essential to infection-related death after bone marrow transplantation. In all, these results demonstrate that influenza A infection in MeCP2Tg3 mice results in pathology affecting both immune and nonhematopoietic cells, suggesting that failure to effectively respond and clear viral respiratory infection has a complex, multicompartment etiology in the context of MeCP2 overexpression. PMID:28138553

  3. Functional interaction of CP2 with GATA-1 in the regulation of erythroid promoters.

    Science.gov (United States)

    Bosè, Francesca; Fugazza, Cristina; Casalgrandi, Maura; Capelli, Alessia; Cunningham, John M; Zhao, Quan; Jane, Stephen M; Ottolenghi, Sergio; Ronchi, Antonella

    2006-05-01

    We observed that binding sites for the ubiquitously expressed transcription factor CP2 were present in regulatory regions of multiple erythroid genes. In these regions, the CP2 binding site was adjacent to a site for the erythroid factor GATA-1. Using three such regulatory regions (from genes encoding the transcription factors GATA-1, EKLF, and p45 NF-E2), we demonstrated the functional importance of the adjacent CP2/GATA-1 sites. In particular, CP2 binds to the GATA-1 HS2 enhancer, generating a ternary complex with GATA-1 and DNA. Mutations in the CP2 consensus greatly impaired HS2 activity in transient transfection assays with K562 cells. Similar results were obtained by transfection of EKLF and p45 NF-E2 mutant constructs. Chromatin immunoprecipitation with K562 cells showed that CP2 binds in vivo to all three regulatory elements and that both GATA-1 and CP2 were present on the same GATA-1 and EKLF regulatory elements. Adjacent CP2/GATA-1 sites may represent a novel module for erythroid expression of a number of genes. Additionally, coimmunoprecipitation and glutathione S-transferase pull-down experiments demonstrated a physical interaction between GATA-1 and CP2. This may contribute to the functional cooperation between these factors and provide an explanation for the important role of ubiquitous CP2 in the regulation of erythroid genes.

  4. Periodic variable stars in CoRoT field LRa02 observed with BEST II

    CERN Document Server

    Kabath, P; Rauer, H; Pasternacki, T; Csizmadia, Sz; Chini, R; Lemke, R; Murphy, M; Fruth, T; Titz, R; Eigmueller, P

    2009-01-01

    The Berlin Exoplanet Search Telescope II (BEST II) is a small wide field-of-view photometric survey telescope system located at the Observatorio Cerro Armazones, Chile. The high duty cycle combined with excellent observing conditions and millimagnitude photometric precision makes this instrument suitable for ground based support observations for the CoRoT space mission. Photometric data of the CoRoT LRa02 target field collected between November 2008 and March 2009 were analysed for stellar variability. The presented results will help in the future analysis of the CoRoT data, particularly in additional science programs related to variable stars. BEST II observes selected CoRoT target fields ahead of the space mission. The photometric data acquired are searched for stellar variability, periodic variable stars are identified with time series analysis of the obtained stellar light curves. We obtained the light curves of 104335 stars in the CoRoT LRa02 field over 41 nights. Variability was detected in light curves...

  5. Supersymmetric M5 brane theories on R × CP2

    Science.gov (United States)

    Kim, Hee-Cheol; Lee, Kimyeong

    2013-07-01

    We propose 4 and 12 supersymmetric conformal Yang-Mills-Chern-Simons theories on R × CP2 as multiple representations of the theory on M5 branes. These theories are obtained by twisted Zk modding and dimensional reduction of the 6d (2,0) superconformal field theory on R × S5 and have a discrete coupling constant 1/{g_{{YM}^2}}=k/{4{π^2}} with natural number k. Instantons in these theories are expected to represent the Kaluza-Klein modes. For the k = 1 , 2 cases, we argue that the number of supersymmetries in our theories should be enhanced to 32 and 16, respectively. For the k = 3 case, only the 4 supersymmetric theory gets the supersymmetric enhancement to 8. For the 4 supersymmetric case, the vacuum structure becomes more complicated as there are degenerate supersymmetric vacua characterized by fuzzy spheres. We calculate the perturbative part of the SU( N ) gauge group Euclidean path integral for the index function at the symmetric phase of the 4 supersymmetric case and confirm it with the known half-BPS index. From the similar twisted Z k modding of the AdS7 × S4 geometry, we speculate that the M region is for k ≲ N 1/3 and the type IIA region is N 1/3 ≲ k ≲ N. When nonperturbative corrections are included, our theories are expected to produce the full index of the 6d (2,0) theory.

  6. Supersymmetric M5 Brane Theories on R x CP2

    CERN Document Server

    Kim, Hee-Cheol

    2012-01-01

    We propose 4 and 12 supersymmetric Yang-Mills-Chern-Simons theories on $\\mathrm{R\\times CP^2}$ obtained by twisted $\\mathrm{Z}_k$ moddings and dimensional reduction of the 6d (2,0) superconformal field theories on $\\mathrm{R\\times S^5}$. These theories have a discrete coupling constant $\\frac{1}{g^2_{YM}} =\\frac{k}{4\\pi^2}$ so that instantons represent the Kaluza-Klein modes correctly. We calculate the perturbative part of the SU(N) gauge group Euclidean path integral for the index function and confirm it with the known half-BPS index. The scalar and fermionic fields have the conformal dimension prescribed by the 6d theory. From the similar twisted $Z_k$ modding of the $\\mathrm{AdS_7\\times S^4}$ geometry, we speculate that the $M$ region is for $k\\lesssim N^{1/3}$ and the type IIA region is $N^{1/3}\\lesssim k \\lesssim N$. When nonperturbative corrections are included, our theory is expected to produce the full index of the 6d (2,0) theory.

  7. Transcription factor CP2 is crucial in hemoglobin synthesis during erythroid terminal differentiation in vitro.

    Science.gov (United States)

    Chae, J H; Lee, Y H; Kim, C G

    1999-09-24

    The transcription factor CP2 was initially identified to bind to the promoter region of the murine alpha-globin gene and known to stimulate the expression of alpha-globin by increasing CP2 transcripts 3- to 5-fold during induced differentiation of mouse erythroleukemic (MEL) cells in vitro. Here, we report that this increment of CP2 expression is crucial in erythroid-specific globin gene expression and hemoglobin synthesis. When antisense CP2 was overexpressed in MEL cells, production of endogenous CP2 protein was reduced 70-80%, and significant loss of its promoter binding activity was observed. During HMBA-induced terminal differentiation of antisense CP2 expressing MEL cells, the transcription of endogenous alpha-globin gene was suppressed as expected. Moreover, both beta-globin gene expression and hemoglobin synthesis were also severely impaired, without affecting the expression of key heme enzyme genes or HMBA-induced proliferation and viability.

  8. CoRoT pictures transiting exoplanets

    CERN Document Server

    Moutou, Claire

    2015-01-01

    The detection and characterization of exoplanets have made huge progresses since the first discoveries in the late nineties. In particular, the independent measurement of the mass and radius of planets, by combining the transit and radial-velociy techniques, allowed exploring their density and hence, their internal structure. With CoRoT (2007-2012), the pioneering CNES space-based mission in this investigation, about thirty new planets were characterized. CoRoT has enhanced the diversity of giant exoplanets and discovered the first telluric exoplanet. Following CoRoT, the NASA Kepler mission has extended our knowledge to small-size planets, multiple systems and planets orbiting binaries. Exploring these new worlds will continue with the NASA/TESS (2017) and ESA/PLATO (2024) missions.

  9. Measurement of quasi-elastic 12C(p,2p) scattering at high momentum transfer

    Science.gov (United States)

    Mardor, Y.; Aclander, J.; Alster, J.; Barton, D.; Bunce, G.; Carroll, A.; Christensen, N.; Courant, H.; Durrant, S.; Gushue, S.; Heppelmann, S.; Kosonovsky, E.; Mardor, I.; Marshak, M.; Makdisi, Y.; Minor, E. D.; Navon, I.; Nicholson, H.; Piasetzky, E.; Roser, T.; Russell, J.; Sutton, C. S.; Tanaka, M.; White, C.; Wu, J.-Y.

    1998-10-01

    We measured the high-momentum transfer [Q2=4.8 and 6.2 (GeV/c)2] quasi-elastic 12C(p,2p) reaction at θcm~=90 deg for 6 and 7.5 GeV/c incident protons. The momentum components of both outgoing protons and the missing energy and momentum of the proton in the nucleus were measured. We verified the validity of the quasi-elastic picture for ground state momenta up to about 0.5 GeV/c. Transverse and longitudinal momentum distributions of the target proton were measured. They have the same shape with a large momentum tail which is not consistent with independent particle models. We observed that the transverse distribution gets wider as the longitudinal component increases in the beam direction.

  10. [Epigenetics and drug addiction: a focus on MeCP2 and on histone acetylation].

    Science.gov (United States)

    Zwiller, Jean

    2015-04-01

    Chronic drug exposure alters gene expression in the brain, which is believed to underlie compulsive drug seeking and drug taking behavior. Recent evidence shows that drug-induced long-term neuroadaptations in the brain are mediated in part by epigenetic mechanisms. By remodeling chromatin, this type of regulation contributes to drug-induced synaptic plasticity that translates into behavioral modifications. How drug-induced alterations in DNA methylation regulate gene expression is reviewed here, with a focus on MeCP2, a protein binding methylated DNA. The importance of histone modifications, especially acetylation is also discussed, with an emphasis on the effects of inhibitors of histone deacetylases on drug-induced behavioral changes. The precise identification of the epigenetic mechanisms that are under the control of drugs of abuse may help to uncover novel targets for the treatment of drug seeking and relapse. © 2015 médecine/sciences – Inserm.

  11. Control of transferrin expression by β-amyloid through the CP2 transcription factor.

    Science.gov (United States)

    Jang, Sang-Min; Kim, Jung-Woong; Kim, Chul-Hong; An, Joo-Hee; Kang, Eun-Jin; Kim, Chul Geun; Kim, Hyun-Jung; Choi, Kyung-Hee

    2010-10-01

    Accumulation of β-amyloid protein (Aβ) is one of the most important pathological features of Alzheimer's disease. Although Aβ induces neurodegeneration in the cortex and hippocampus through several molecular mechanisms, few studies have evaluated the modulation of transcription factors during Aβ-induced neurotoxicity. Therefore, in this study, we investigated the transcriptional activity of transcription factor CP2 in neuronal damage mediated by Aβ (Aβ(1-42) and Aβ(25-35) ). An unbiased motif search of the transferrin promoter region showed that CP2 binds to the transferrin promoter, an iron-regulating protein, and regulates transferrin transcription. Ectopic expression of CP2 led to increased transferrin expression at both the mRNA and protein levels, whereas knockdown of CP2 down-regulated transferrin mRNA and protein expression. Moreover, CP2 trans-activated transcription of a transferrin reporter gene. An electrophoretic mobility shift assay and a chromatin immunoprecipitation assay showed that CP2 binds to the transferrin promoter region. Furthermore, the binding affinity of CP2 to the transferrin promoter was regulated by Aβ, as Aβ (Aβ(1-42) and Aβ(25-35) ) markedly increased the binding affinity of CP2 for the transferrin promoter. Taken together, these results suggest that CP2 contributes to the pathogenesis of Alzheimer's disease by inducing transferrin expression via up-regulating its transcription.

  12. Limits to the presence of transiting circumbinary planets in CoRoT data

    CERN Document Server

    Klagyivik, P; Cabrera, J; Csizmadia, Sz; Almenara, J M

    2016-01-01

    The CoRoT mission during its flight-phase 2007-2012 delivered the light-curves for over 2000 eclipsing binaries. Data from the Kepler mission have proven the existence of several transiting circumbinary planets. Albeit light-curves from CoRoT have typically lower precision and shorter coverage, CoRoT's number of targets is similar to Kepler, and some of the known circumbinary planets could potentially be detected in CoRoT data as well. The aim of this work has been a revision of the entire CoRoT data-set for the presence of circumbinary planets, and the derivation of limits to the abundances of such planets. We developed a code which removes the light curve of the eclipsing binaries and searches for quasi-periodic transit-like features in a light curve after removal of binary eclipses and instrumental features. The code needs little information on the sample systems and can be used for other space missions as well, like Kepler, K2, TESS and PLATO. The code is broad in the requirements leading to detections, b...

  13. Reciprocal localization of transcription factors YY1 and CP2c in spermatogonial stem cells and their putative roles during spermatogenesis.

    Science.gov (United States)

    Kim, Ji Sook; Chae, Ji Hyung; Cheon, Yong-Pil; Kim, Chul Geun

    2016-09-01

    Maintaining stemness and permitting differentiation mediated by combinations of transcription factors (TFs) are key aspects of mammalian spermatogenesis. It has been established that yin yang 1 (YY1), a target factor of mammalian polycomb repressive complex 2 (PRC2) and a regulator of stemness, is involved in the stable maintenance of prophase stage spermatocytes. Recently, we have demonstrated that the TF CP2c partners with YY1 in some cells to antagonistically regulate the other protein's function. To date, the functional roles of YY1 and CP2c in spermatogonial stem cells and their derived germ cells remain unclear. Here, we investigated the expression of YY1 and CP2c in mouse gonocytes and germ cells using tissue immunohistochemical and immunofluorescence analyses. At E14.5, both YY1 and CP2c were stained in gonocytes and Sertoli cells in testicular cords, showing different proportion and density of immunoreactivity. However, in adult testes, YY1 was localized in the nuclei of spermatogonial stem cells and spermatocytes, but not in spermatozoa. It was also detected in spermatogonia and spermatids in a stage-specific manner during spermatogenic cycle. CP2c could be detected mostly in the cytoplasm of spermatocytes but not at all in spermatogonial stem cells, indicating mutually exclusive expression of CP2c and YY1. Interestingly, however, CP2c was stained in the cytoplasm and nucleus of spermatogonia at elongation and release stages, and co-localized with YY1 in the nucleus at grouping, maturation, and releasing stages. Neither YY1 nor CP2c was expressed in spermatozoa. Our data indicate that YY1 strongly localizes in the spermatogonial stem cells and co-localizes heterogeneously with CP2c to permit spermatogenesis, and also suggest that YY1 is essential for stemness of spermatogonial stem cells (SCs) whereas CP2c is critical for the commitment of spermatogonia and during the progression of spermatogonia to spermatids. This evaluation expands our understanding of

  14. A Role for MeCP2 in Switching Gene Activity via Chromatin Unfolding and HP1 gamma Displacement

    NARCIS (Netherlands)

    Brink, Maartje C.; Piebes, Diewertje G. E.; de Groote, Marloes L.; Luijsterburg, Martijn S.; Casas-Delucchi, Corella S.; van Driel, Roel; Rots, Marianne G.; Cardoso, M. Cristina; Verschure, Pernette J.

    2013-01-01

    Methyl-CpG-binding protein 2 (MeCP2) is generally considered to act as a transcriptional repressor, whereas recent studies suggest that MeCP2 is also involved in transcription activation. To gain insight into this dual function of MeCP2, we assessed the impact of MeCP2 on higher-order chromatin stru

  15. Report on the CoRoT Evolution and Seismic Tools Activity

    CERN Document Server

    Monteiro, M J P F G; Montalban, J; Christensen-Dalsgaard, J; Castro, M; Degl'Innocenti, S; Moya, A; Roxburgh, I W; Scuflaire, R; Baglin, A; Cunha, M S; Eggenberger, P; Fernandes, J; Goupil, M J; Hui-Bon-Hoa, A; Marconi, M; Marques, J P; Michel, E; Miglio, A; Morel, P; Pichon, B; Moroni, P G P; Provost, J; Ruoppo, A; Suárez, J C; Suran, M; Teixeira, T C

    2006-01-01

    We present the work undertaken by the Evolution and Seismic Tools Activity (ESTA) team of the CoRoT Seismology Working Group. We have focused on two main tasks: Task 1 - now finished - has aimed at testing, comparing and optimising seven stellar evolution codes which will be used to model the internal structure and evolution of the CoRoT target stars. Task 2, still underway, aims at testing, comparing and optimising different seismic codes used to calculate the oscillations of models for different types of stars. The results already obtained are quite satisfactory, showing minor differences between the different numerical tools provided the same assumptions on the physical parameters are made. This work gives us confidence on the numerical tools that will be available to interpret the future CoRoT seismic data.

  16. Inhibition of the processing of miR-25 by HIPK2-Phosphorylated-MeCP2 induces NOX4 in early diabetic nephropathy

    Science.gov (United States)

    Oh, Hyung Jung; Kato, Mitsuo; Deshpande, Supriya; Zhang, Erli; Sadhan, Das; Lanting, Linda; Wang, Mei; Natarajan, Rama

    2016-01-01

    Phosphorylated methyl-CpG binding protein2 (p-MeCP2) suppresses the processing of several microRNAs (miRNAs). Homeo-domain interacting protein kinase2 (HIPK2) phosphorylates MeCP2, a known transcriptional repressor. However, it is not known if MeCP2 and HIPK2 are involved in processing of miRNAs implicated in diabetic nephropathy. p-MeCP2 and HIPK2 levels were significantly increased, but Seven in Absentia Homolog1 (SIAH1), which mediates proteasomal degradation of HIPK2, was decreased in the glomeruli of streptozotocin injected diabetic mice. Among several miRNAs, miR-25 and its precursor were significantly decreased in diabetic mice, whereas primary miR-25 levels were significantly increased. NADPH oxidase4 (NOX4), a target of miR-25, was significantly increased in diabetic mice. Protein levels of p-MeCP2, HIPK2, and NOX4 were increased in high glucose (HG)- or TGF-β-treated mouse glomerular mesangial cells (MMCs). miR-25 (primary, precursor, and mature) and mRNA levels of genes indicated in the in vivo study showed similar trends of regulation in MMCs treated with HG or TGF-β. The HG- or TGF-β-induced upregulation of p-MeCP2, NOX4 and primary miR-25, but downregulation of precursor and mature miR-25, were attenuated by Hipk2 siRNA. These results demonstrate a novel role for the SIAH1/HIPK2/MeCP2 axis in suppressing miR-25 processing and thereby upregulating NOX4 in early diabetic nephropathy. PMID:27941951

  17. Identification of Variable Stars in COROT's First Main Observing Field (LRc1)

    CERN Document Server

    Karoff, C; Erikson, A; Voss, H; Kabath, P; Wiese, T; Deleuil, M; Moutou, C; Meunier, J C; Deeg, H; 10.1086/519524

    2009-01-01

    The COROT space mission will monitor several target fields for up to 150 days to perform asteroseismology and to search for extrasolar planets by photometric transits. Variable stars in the target fields are important objects for additional scientific studies but can also disturb the search for planetary transits. A variability characterization of the target fields prior to COROT observations is therefore important for two reasons: to find interesting variable stars to monitor further and to make an analysis of the impact of the variable stars on detecting extrasolar planet transits with COROT. The Berlin Exoplanet Search Telescope (BEST) is a small wide-angle telescope dedicated to high-precision photometry. It has observed a 9 square degree field of view centered at (alpha, delta)=(19h00m00.0s, +00deg01'55.2") (J2000.0) over 98 nights to search for variable stars in the surroundings of the first long-run target field (LRc1) of the COROT space mission. In this data set we identified 92 periodic variable star...

  18. MeCP2 Rett mutations affect large scale chromatin organization

    DEFF Research Database (Denmark)

    Gupta, Noopur Agarwal; Becker, Annette; Jost, K Laurence

    2011-01-01

    Rett syndrome is a neurological, X chromosomal-linked disorder associated with mutations in the MECP2 gene. MeCP2 protein has been proposed to play a role in transcriptional regulation as well as in chromatin architecture. Since MeCP2 mutant cells exhibit surprisingly mild changes in gene...... expression, we have now explored the possibility that Rett mutations may affect the ability of MeCP2 to bind and organize chromatin. We found that all but one of the 21 missense MeCP2 mutants analyzed accumulated at heterochromatin and about half of them were significantly affected. Furthermore, two......-thirds of all mutants showed a significantly decreased ability to cluster heterochromatin. Three mutants containing different proline substitutions (P101H, P101R and P152R) were severely affected only in heterochromatin clustering and located far away from the DNA interface in the MeCP2 methyl-binding domain...

  19. Secondary eclipses in the CoRoT light curves

    Directory of Open Access Journals (Sweden)

    Belmonte Juan Antonio

    2013-04-01

    Full Text Available We identify and characterize secondary eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b eclipses.

  20. The CytR repressor antagonizes cyclic AMP-cyclic AMP receptor protein activation of the deoCp2 promoter of Escherichia coli K-12

    DEFF Research Database (Denmark)

    Søgaard-Andersen, Lotte; Martinussen, J; Møllegaard, N E

    1990-01-01

    We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) Cyt......R selectively regulated cAMP-CRP-dependent initiations, although transcription started from the same site in deoCp2 in the absence or presence of cAMP-CRP; (ii) deletion of the uppermost cAMP-CRP target (CRP-2) resulted in loss of CytR regulation, but had only a minor effect on positive control by the c...... are required for efficient CytR repression of deoCp2. Models for the action of CytR are discussed in light of these findings....

  1. Regulation mechanism and research progress of MeCP2 in Rett syndrome%MeCP2在Rett综合征中的调控机制

    Institute of Scientific and Technical Information of China (English)

    杨文旭; 潘虹

    2014-01-01

    Rett综合征(Rett syndrome,RTT)是一种X连锁的神经发育障碍性遗传病,是导致女性严重智力障碍的主要原因之一.编码甲基化CpG结合蛋白2(Methyl-CpG-binding protein 2,MeCP2)基因突变是RTT主要的遗传病理学改变,MeCP2作为转录抑制因子调控基因表达.在RTT发病机制中,由于缺乏MeCP2与甲基化DNA的正确结合,阻碍了它对下游靶基因表达的正常调控,最终导致脑功能障碍.目前,对MeCP2在脑发育过程中的作用以及如何导致RTT的发生,其机制尚不清楚.文章从MECP2基因和MeCP2蛋白两个方面,对基因结构、蛋白质功能以及在分子水平上的调控机制进行了综述,以期为RTT的发病机制研究提供新思路.

  2. MeCP2: multifaceted roles in gene regulation and neural development.

    Science.gov (United States)

    Cheng, Tian-Lin; Qiu, Zilong

    2014-08-01

    Methyl-CpG-binding protein 2 (MeCP2) is a classic methylated-DNA-binding protein, dysfunctions of which lead to various neurodevelopmental disorders such as Rett syndrome and autism spectrum disorder. Initially recognized as a transcriptional repressor, MeCP2 has been studied extensively and its functions have been expanded dramatically in the past two decades. Recently, it was found to be involved in gene regulation at the post-transcriptional level. MeCP2 represses nuclear microRNA processing by interacting directly with the Drosha/DGCR8 complex. In addition to its multifaceted functions, MeCP2 is remarkably modulated by posttranslational modifications such as phosphorylation, SUMOylation, and acetylation, providing more regulatory dimensions to its functions. The role of MeCP2 in the central nervous system has been studied extensively, from neurons to glia. Future investigations combining molecular, cellular, and physiological methods are necessary for defining the roles of MeCP2 in the brain and developing efficient treatments for MeCP2-related brain disorders.

  3. Characterization of the molecularly cloned murine alpha-globin transcription factor CP2.

    Science.gov (United States)

    Lim, L C; Fang, L; Swendeman, S L; Sheffery, M

    1993-08-25

    We recently cloned human and murine cDNAs that encode CP2, a transcription factor that interacts with the murine alpha-globin promoter. In this report, we exploited our ability to express CP2 in bacteria and eukaryotic cells to further investigate factor activities in vitro and in vivo. CP2 expressed in bacteria was significantly enriched and used in a series of DNase I footprinting and electrophoretic gel shift assays. The results suggest that CP2 binds a hyphenated recognition sequence motif that spans one DNA helix turn. In addition, the enriched bacterial protein activated transcription of alpha-globin promoter templates approximately 3- to 4-fold in vitro. We then tested the effect of elevating CP2 levels 2.5- to 5.5-fold in vivo using both transient and stable transformation assays. When a reporter construct comprised of the intact murine alpha-globin promoter driving the bacterial chloramphenicol acetyltransferase (CAT) gene was introduced into these overexpressing cells, we observed a 3- to 6-fold increase in CAT activity when compared to cells expressing normal levels of CP2. These results define the CP2 factor binding site in more detail and help characterize the activities of the factor in vivo.

  4. Spectral characterization and differential rotation study of active CoRoT stars

    Science.gov (United States)

    Nagel, E.; Czesla, S.; Schmitt, J. H. M. M.

    2016-05-01

    The CoRoT space telescope observed nearly 160 000 light curves. Among the most outstanding is that of the young, active planet host star CoRoT-2A. In addition to deep planetary transits, the light curve of CoRoT-2A shows strong rotational variability and a superimposed beating pattern. To study the stars that produce such an intriguing pattern of photometric variability, we identified a sample of eight stars with rotation periods between 0.8 and 11 days and photometric variability amplitudes of up to 7.5%, showing a similar CoRoT light curve. We also obtained high-resolution follow-up spectroscopy with TNG/SARG and carried out a spectral analysis with SME and MOOG. We find that the color dependence of the light curves is consistent with rotational modulation due to starspots and that latitudinal differential rotation provides a viable explanation for the light curves, although starspot evolution is also expected to play an important role. Our MOOG and SME spectral analyses provide consistent results, showing that the targets are dwarf stars with spectral types between F and mid-K. Detectable Li i absorption in four of the targets confirms a low age of 100-400 Myr also deduced from gyrochronology. Our study indicates that the photometric beating phenomenon is likely attributable to differential rotation in fast-rotating stars with outer convection zones.

  5. On Einstein metrics, normalized Ricci flow and smooth structures on $3\\mathbb{CP}^2 # k \\bar{\\mathbb{CP}}^2$

    CERN Document Server

    Torres, Rafael

    2010-01-01

    In this paper, first we consider the existence and non-existence of Einstein metrics on the topological 4-manifolds $3\\mathbb{CP}^2 # k \\bar{\\mathbb{CP}}^2$ (for $k \\in \\{11, 13, 14, 15, 16, 17, 18\\}$) by using the idea of \\cite{[RS]} and the constructions in \\cite{[PPS]} and in \\cite{[PPS1]}. Then, we study the existence or non-existence of non-singular solutions of the normalized Ricci flow on the exotic smooth structures of these topological manifolds by employing the obstruction developed in \\cite{[MI]}.

  6. Screen for reactivation of MeCP2 on the inactive X chromosome identifies the BMP/TGF-β superfamily as a regulator of XIST expression.

    Science.gov (United States)

    Sripathy, Smitha; Leko, Vid; Adrianse, Robin L; Loe, Taylor; Foss, Eric J; Dalrymple, Emily; Lao, Uyen; Gatbonton-Schwager, Tonibelle; Carter, Kelly T; Payer, Bernhard; Paddison, Patrick J; Grady, William M; Lee, Jeannie T; Bartolomei, Marisa S; Bedalov, Antonio

    2017-02-14

    Rett syndrome (RS) is a debilitating neurological disorder affecting mostly girls with heterozygous mutations in the gene encoding the methyl-CpG-binding protein MeCP2 on the X chromosome. Because restoration of MeCP2 expression in a mouse model reverses neurologic deficits in adult animals, reactivation of the wild-type copy of MeCP2 on the inactive X chromosome (Xi) presents a therapeutic opportunity in RS. To identify genes involved in MeCP2 silencing, we screened a library of 60,000 shRNAs using a cell line with a MeCP2 reporter on the Xi and found 30 genes clustered in seven functional groups. More than half encoded proteins with known enzymatic activity, and six were members of the bone morphogenetic protein (BMP)/TGF-β pathway. shRNAs directed against each of these six genes down-regulated X-inactive specific transcript (XIST), a key player in X-chromosome inactivation that encodes an RNA that coats the silent X chromosome, and modulation of regulators of this pathway both in cell culture and in mice demonstrated robust regulation of XIST. Moreover, we show that Rnf12, an X-encoded ubiquitin ligase important for initiation of X-chromosome inactivation and XIST transcription in ES cells, also plays a role in maintenance of the inactive state through regulation of BMP/TGF-β signaling. Our results identify pharmacologically suitable targets for reactivation of MeCP2 on the Xi and a genetic circuitry that maintains XIST expression and X-chromosome inactivation in differentiated cells.

  7. Invariant algebraic curves and rational first integrals of holomorphic foliations in CP(2)

    Institute of Scientific and Technical Information of China (English)

    张祥

    2003-01-01

    In this paper, using the tools of algebraic geometry we provide sufficient conditions for a holomor-phic foliation in CP(2) to have a rational first integral. Moreover, we obtain an upper bound of the degreesof invariant algebraic curves of a holomorphic foliation in CP(2). Then we use these results to prove that anyholomorphic foliation of degree 2 does not have cubic limit cycles.

  8. A novel Cryptosporidium parvum antigen, CP2, preferentially associates with membranous structures.

    Science.gov (United States)

    O'Hara, Steven P; Yu, Jae-Ran; Lin, Jim Jung-Ching

    2004-03-01

    The present study addresses the cloning and characterization of a Cryptosporidium parvum antigen, CP2. Sequencing of cDNA and genomic clones revealed a novel gene capable of coding a message of 2,136 nucleotides flanked by 28 and 140 nucleotides of the 5'- and 3'-noncoding regions, respectively. The deduced amino acid sequence suggests that CP2 is a secreted and/or membrane protein. Immunofluorescence microscopy detected CP2 enrichment in sporozoites that subsequently appeared to encase type I meronts in infected HCT-8 cells. Immunogold electron microscopy revealed that CP2 consistently localized to membranous structures throughout development. In addition, progression from macrogametocyte to sporulated oocyst revealed CP2 initially at the periphery of amylopectin-like granules, in the cytoplasm and discrete vesicles, the parasitophorous vacuole, on the surface of sporozoites, and finally on the parasitophorous vacuole membrane (PVM). The observed expression pattern suggests that CP2 may be involved in the invasion process and/or PVM integrity.

  9. MeCP2 SUMOylation rescues Mecp2-mutant-induced behavioural deficits in a mouse model of Rett syndrome.

    Science.gov (United States)

    Tai, Derek J C; Liu, Yen C; Hsu, Wei L; Ma, Yun L; Cheng, Sin J; Liu, Shau Y; Lee, Eminy H Y

    2016-02-04

    The methyl-CpG-binding protein 2 (MeCP2) gene, MECP2, is an X-linked gene encoding the MeCP2 protein, and mutations of MECP2 cause Rett syndrome (RTT). However, the molecular mechanism of MECP2-mutation-caused RTT is less known. Here we find that MeCP2 could be SUMO-modified by the E3 ligase PIAS1 at Lys-412. MeCP2 phosphorylation (at Ser-421 and Thr-308) facilitates MeCP2 SUMOylation, and MeCP2 SUMOylation is induced by NMDA, IGF-1 and CRF in the rat brain. MeCP2 SUMOylation releases CREB from the repressor complex and enhances Bdnf mRNA expression. Several MECP2 mutations identified in RTT patients show decreased MeCP2 SUMOylation. Re-expression of wild-type MeCP2 or SUMO-modified MeCP2 in Mecp2-null neurons rescues the deficits of social interaction, fear memory and LTP observed in Mecp2 conditional knockout (cKO) mice. These results together reveal an important role of MeCP2 SUMOylation in social interaction, memory and synaptic plasticity, and that abnormal MeCP2 SUMOylation is implicated in RTT.

  10. Reaction of (CP(2)asterisk-lnH)(2) (ln=Y, La) and CP(2)asterisk-Y(2-C(6)H(4)CH(2)NMe(2)) with esters and amides and molecular-structure of [CP(2)asterisk-Y(mu- ocme=chc(oet)o)](2)

    NARCIS (Netherlands)

    Deelman, B.J; Wierda, F.; Meetsma, A.; Teuben, J.H

    1995-01-01

    The activation of esters and amides by (Cp(2)*LnH)(2) [Ln = Y (1a), Ln = La (1b), Cp*=C(5)Me] and Cp(2)*Y(2-C(6)H(4)CH(2)NMe(2)) (2) is described. Compounds 1a and 1b react with ethyl acetate to form Cp(2)*YOEt (3a) and Cp(2)*LaOEt (30). With 1a and ethyl benzoate a 1:1 mixture of 3a and

  11. The CytR repressor antagonizes cyclic AMP-cyclic AMP receptor protein activation of the deoCp2 promoter of Escherichia coli K-12

    DEFF Research Database (Denmark)

    Søgaard-Andersen, L; Martinussen, J; Møllegaard, N E

    1990-01-01

    We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) C...... are required for efficient CytR repression of deoCp2. Models for the action of CytR are discussed in light of these findings.......We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) Cyt......R selectively regulated cAMP-CRP-dependent initiations, although transcription started from the same site in deoCp2 in the absence or presence of cAMP-CRP; (ii) deletion of the uppermost cAMP-CRP target (CRP-2) resulted in loss of CytR regulation, but had only a minor effect on positive control by the c...

  12. Identification and characterization of four novel peptide motifs that recognize distinct regions of the transcription factor CP2.

    Science.gov (United States)

    Kang, Ho Chul; Chung, Bo Mee; Chae, Ji Hyung; Yang, Sung-Il; Kim, Chan Gil; Kim, Chul Geun

    2005-03-01

    Although ubiquitously expressed, the transcriptional factor CP2 also exhibits some tissue- or stage-specific activation toward certain genes such as globin in red blood cells and interleukin-4 in T helper cells. Because this specificity may be achieved by interaction with other proteins, we screened a peptide display library and identified four consensus motifs in numerous CP2-binding peptides: HXPR, PHL, ASR and PXHXH. Protein-database searching revealed that RE-1 silencing factor (REST), Yin-Yang1 (YY1) and five other proteins have one or two of these CP2-binding motifs. Glutathione S-transferase pull-down and coimmunoprecipitation assays showed that two HXPR motif-containing proteins REST and YY1 indeed were able to bind CP2. Importantly, this binding to CP2 was almost abolished when a double amino acid substitution was made on the HXPR sequence of REST and YY1 proteins. The suppressing effect of YY1 on CP2's transcriptional activity was lost by this point mutation on the HXPR sequence of YY1 and reduced by an HXPR-containing peptide, further supporting the interaction between CP2 and YY1 via the HXPR sequence. Mapping the sites on CP2 for interaction with the four distinct CP2-binding motifs revealed at least three different regions on CP2. This suggests that CP2 recognizes several distinct binding motifs by virtue of employing different regions, thus being able to interact with and regulate many cellular partners.

  13. The CoRoT mission's exoplanet program

    Directory of Open Access Journals (Sweden)

    Deeg H.J.

    2013-04-01

    Full Text Available The CoRoT space observatory was launched at the end of 2006 and has been delivering scientific data from early 2007 until its recent interruption, on 2 Nov. 2012, leading to the discovery of over 30 transiting planets. Here we give an overview over the most relevant results from CoRoT's exoplanet detection program.

  14. HD 174884: a strongly eccentric, short-period early-type binary system discovered by CoRoT

    CERN Document Server

    Maceroni, C; Michel, E; Harmanec, P; Prsa, A; Briquet, M; Niemczura, E; Morel, T; Ladjal, D; Auvergne, M; Baglin, A; Baudin, F; Catala, C; Samadi, R; Aerts, C

    2009-01-01

    Accurate photometric CoRoT space observations of a secondary seismological target, HD 174884, led to the discovery that this star is an astrophysically important double-lined eclipsing spectroscopic binary in an eccentric orbit (e of about 0.3), unusual for its short (3.65705d) orbital period. The high eccentricity, coupled with the orientation of the binary orbit in space, explains the very unusual observed light curve with strongly unequal primary and secondary eclipses having the depth ratio of 1-to-100 in the CoRoT 'seismo' passband. Without the high accuracy of the CoRoT photometry, the secondary eclipse, 1.5 mmag deep, would have gone unnoticed. A spectroscopic follow-up program provided 45 high dispersion spectra. The analysis of the CoRoT light curve was performed with an adapted version of PHOEBE that supports CoRoT passbands. The final solution was obtained by simultaneous fitting of the light and the radial velocity curves. Individual star spectra were derived by spectrum disentangling. The uncerta...

  15. Reaction of (CP(2)asterisk-lnH)(2) (ln=Y, La) and CP(2)asterisk-Y(2-C(6)H(4)CH(2)NMe(2)) with esters and amides and molecular-structure of [CP(2)asterisk-Y(mu- ocme=chc(oet)o)](2)

    NARCIS (Netherlands)

    Deelman, B.J; Wierda, F.; Meetsma, A.; Teuben, J.H

    1995-01-01

    The activation of esters and amides by (Cp(2)*LnH)(2) [Ln = Y (1a), Ln = La (1b), Cp*=C(5)Me] and Cp(2)*Y(2-C(6)H(4)CH(2)NMe(2)) (2) is described. Compounds 1a and 1b react with ethyl acetate to form Cp(2)*YOEt (3a) and Cp(2)*LaOEt (30). With 1a and ethyl benzoate a 1:1 mixture of 3a and Cp(2)*YOCH(

  16. CoRoT and asteroseismology. Preparatory work and simultaneous ground-based monitoring

    CERN Document Server

    Poretti, Ennio; Uytterhoeven, Katrien; Cutispoto, Giuseppe; Distefano, Elisa; Romano, Paolo

    2007-01-01

    The successful launch of the CoRoT (COnvection, ROtation and planetary Transits) satellite opens a new era in asteroseismology. The space photometry is complemented by high-resolution spectroscopy and multicolour photometry from ground, to disclose the pulsational content of the asteroseismic targets in the most complete way. Some preliminary results obtained with both types of data are presented. The paper is based on observations collected at S. Pedro Martir, Serra La Nave, La Silla, and Telescopio Nazionale Galileo Observatories.

  17. Binding of the Rett syndrome protein, MeCP2, to methylated and unmethylated DNA and chromatin.

    Science.gov (United States)

    Hansen, Jeffrey C; Ghosh, Rajarshi P; Woodcock, Christopher L

    2010-10-01

    Methylated CpG Binding Protein 2 (MeCP2) is a nuclear protein named for its ability to selectively recognize methylated DNA. Much attention has been focused on understanding MeCP2 structure and function in the context of its role in Rett syndrome, a severe neurodevelopmental disorder that afflicts one in 10,000-15,000 girls. Early studies suggested a connection between DNA methylation, MeCP2, and establishment of a repressive chromatin structure at specific gene promoters. However, it is now recognized that MeCP2 can both activate and repress specific genes depending on the context. Likewise, in the cell, MeCP2 is bound to unmethylated DNA and chromatin in addition to methylated DNA. Thus, to understand the molecular basis of MeCP2 functionality, it is necessary to unravel the complex interrelationships between MeCP2 binding to unmethylated and methylated regions of the genome. MeCP2 is unusual and interesting in that it is an intrinsically disordered protein, that is, much of its primary sequence fails to fold into secondary structure and yet is functional. The unique structure of MeCP2 is the subject of the first section of this article. We then discuss recent investigations of the in vitro binding of MeCP2 to unmethylated and methylated DNA, and the potential ramifications of this work for in vivo function. We close by focusing on mechanistic studies indicating that the binding of MeCP2 to chromatin results in compaction into local (secondary) and global (tertiary) higher order structures. MeCP2 also competes with histone H1 for nucleosomal binding sites. The recent finding that MeCP2 is found at near stoichiometric levels with nucleosomes in neuronal cells underscores the multiple modes of engagement of MeCP2 with the genome, which include the cooperative tracking of methylation density.

  18. Evidence for Corotating Convection in Saturn's Magnetosphere

    Science.gov (United States)

    Kivelson, M. G.; Southwood, D. J.; Dougherty, M. K.

    2006-05-01

    Saturn's magnetic field exhibits a high degree of azimuthal symmetry, yet the field and plasma signatures of the magnetosphere are modulated at a period close to that of planetary rotation. How, then, is a clear periodicity imposed on the magnetic field and plasma of the planetary magnetosphere? In this talk, Cassini magnetometer data are used to develop a scenario for the dynamics of the Saturn magnetosphere. The proposal is that mass transport, accomplished in the inner magnetosphere by interchange motion, feeds into the outer magnetosphere where ballooning driven by centrifugal stress leads to outward transport, field reconnection and plasma loss in a favored local time sector; flux is transported inward in other regions. The model is closely related to the concept of corotating convection proposed by Dessler, Hill, and co-workers for Jupiter. The proposed mechanism can be consistent with aspects of the empirical camshaft model introduced by Espinosa et al., 2003 to explain Pioneer and Voyager magnetometer data. Anomalous transport here proposed could originate from a localized ionospheric conductivity anomaly. The resulting cyclic stress modulates the current in the current sheet and can account for its north-south excursions. The convection patterns proposed also imply that corotating, field-aligned currents would be a basic feature of the Saturn system.

  19. CP2 binding to the promoter is essential for the enhanced transcription of globin genes in erythroid cells.

    Science.gov (United States)

    Chae, Ji Hyung; Kim, Chul Geun

    2003-02-28

    We have previously reported that the reduced level of CP2 suppresses the mouse alpha- and beta-globin gene expression and hemoglobin synthesis during terminal differentiation of mouse erythroleukemia (MEL) cells in vitro [Chae et al. (1999)]. As an extension of this study, we demonstrated that human alpha-, epsilon-, and gamma- globin genes were also suppressed by the reduced expression of CP2 in K562 cells. To address how much CP2 contributes in the regulation of globin gene expression, we measured transcriptional activities of the wild type alpha-globin promoter and its various factor-binding sites mutants in erythroid and nonerythroid cells. Interestingly, CP2 site dependent transcriptional activation occurred in an erythroid-cell specific manner, even though CP2 is ubiquitously expressed. In addition, CP2 site mutation within the alpha-promoter severely suppressed promoter activity in differentiated, but not in undifferentiated MEL cells, suggesting that the CP2 binding site is needed for the enhanced transcription of globin genes during erythroid differentiation. When the human beta-globin locus control region was linked to the alpha-promoter, suppression was more severe in the CP2 site mutant in differentiated MEL cells. Overall data indicate that CP2 is a major factor in the regulation of globin expression in human and mouse erythroid cells, and CP2 binding to the globin gene promoter is essential for the enhanced transcription of globin genes in erythroid differentiation.

  20. 不动点集为CP1(2m) ∪CP2(2m) ∪CP(2n+1)的对合%Involutions Fixing CP1(2m) ∪ CP2(2m) ∪ CP(2n + 1)

    Institute of Scientific and Technical Information of China (English)

    赵素倩; 杨林广

    2015-01-01

    设(Mr,T)是一个带有光滑对合T的r维光滑闭流形,对合的不动点集为CP1(2m)∪ CP2(2m)∪CP(2n+1)(m≥1),其中CP(n)表示n维复射影空间.证明了当r>4m+ 4n+4时,对合(Mr,T)存在且协边.

  1. Corot 310266512: A Light Curve With Primary, Secondary And Tertiary Eclipses

    Directory of Open Access Journals (Sweden)

    Fernández Fernández Javier

    2015-01-01

    Full Text Available We present the photometric study of an interesting target in the CoRoT exoplanet database: CoRoT 310266512. Its light curve shows primary, secondary and tertiary eclipses that suggests the presence of at least three celestial bodies. The primary and secondary eclipses have the same orbital period, 7.42 days, and the tertiary eclipse has an orbital period of 3.27 days. Two of the tertiary eclipses fall within a primary eclipse and a secondary eclipse. The properties of the light curve indicate the presence of two physically separated systems. The primary and secondary eclipses corresponds to a binary system (System I. The tertiary eclipses correspond to a star-planet system or a star-dwarf system (System II. Some parameters of these two systems are obtained from JKTEBOP [1] program.

  2. Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements.

    Directory of Open Access Journals (Sweden)

    Carl O Olson

    Full Text Available MeCP2 is a critical epigenetic regulator in brain and its abnormal expression or compromised function leads to a spectrum of neurological disorders including Rett Syndrome and autism. Altered expression of the two MeCP2 isoforms, MeCP2E1 and MeCP2E2 has been implicated in neurological complications. However, expression, regulation and functions of the two isoforms are largely uncharacterized. Previously, we showed the role of MeCP2E1 in neuronal maturation and reported MeCP2E1 as the major protein isoform in the adult mouse brain, embryonic neurons and astrocytes. Recently, we showed that DNA methylation at the regulatory elements (REs within the Mecp2 promoter and intron 1 impact the expression of Mecp2 isoforms in differentiating neural stem cells. This current study is aimed for a comparative analysis of temporal, regional and cell type-specific expression of MeCP2 isoforms in the developing and adult mouse brain. MeCP2E2 displayed a later expression onset than MeCP2E1 during mouse brain development. In the adult female and male brain hippocampus, both MeCP2 isoforms were detected in neurons, astrocytes and oligodendrocytes. Furthermore, MeCP2E1 expression was relatively uniform in different brain regions (olfactory bulb, striatum, cortex, hippocampus, thalamus, brainstem and cerebellum, whereas MeCP2E2 showed differential enrichment in these brain regions. Both MeCP2 isoforms showed relatively similar distribution in these brain regions, except for cerebellum. Lastly, a preferential correlation was observed between DNA methylation at specific CpG dinucleotides within the REs and Mecp2 isoform-specific expression in these brain regions. Taken together, we show that MeCP2 isoforms display differential expression patterns during brain development and in adult mouse brain regions. DNA methylation patterns at the Mecp2 REs may impact this differential expression of Mecp2/MeCP2 isoforms in brain regions. Our results significantly contribute

  3. Anisotropy and Corotation of Galactic Cosmic Rays

    CERN Document Server

    Amenomori, M; Bi, X J; Chen, D; Cui, S W; Danzengluobu; Ding, L K; Ding, X H; Feng Cun Feng; Zhaoyang Feng; Feng, Z Y; Gao, X Y; Geng, Q X; Guo, H W; He, H H; He, M; Hibino, K; Hotta, N; Haibing, H; Hu, H B; Huang, J; Huang, Q; Jia, H Y; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren; Le, G M; Li, A F; Li, J Y; Lou, Y Q; Lü, H; Lu, S L; Meng, X R; Mizutani, K; Mu, J; Munakata, K; Nagai, A; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ouchi, T; Ozawa, S; Ren, J R; Saitô, T; Saito, T Y; Sakata, M; Sako, T K; Sasaki, T; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, B; Wang, H; Wang, X; Wang, Y G; Wu, H R; Xue Liang; Yamamoto, Y; Yan, C T; Yang, X C; Yasue, S; Ye, Z H; Yu, G C; Yuan, A F; Yuda, T; Zhang, H M; Zhang, J L; Zhang, N J; Zhang, X Y; Zhang, Y; Zhaxisangzhu; Zhou, X X

    2006-01-01

    The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

  4. Limits to the presence of transiting circumbinary planets in CoRoT Data

    Science.gov (United States)

    Klagyivik, P.; Deeg, H. J.; Cabrera, J.; Csizmadia, Sz.; Almenara, J. M.

    2017-06-01

    Aims: During its flight phase, from 2007-2012, the CoRoT mission delivered light curves for over 2000 eclipsing binaries. Data from the Kepler mission have proven the existence of several transiting circumbinary planets. While light curves from CoRoT typically have lower precision and shorter coverage, the number of CoRoT targets is similar to that of Kepler and some of the known circumbinary planets could potentially be detected in CoRoT data as well. The aim of this work was to reanalyse the entire CoRoT Data set to search for the presence of circumbinary planets and to derive limits on the abundances of such planets. Methods: We developed a code that removes the signatures of eclipsing binaries from the light curves, and searches for quasi-periodic, transit-like features in the light curves after removal of binary eclipses and instrumental features. The code requires little information on sample systems and can also be used for other space missions, such as Kepler, K2, TESS, and PLATO. The code is broad in the requirements leading to detections, but was tuned to deliver an amount of detections that are manageable in a subsequent, mainly visual, assessment of their origin. Results: We identified three planet candidates in the CoRoT sample whose transits would have arisen from a single pass across the central binary; however, no candidates with transit events from multiple planetary orbits remained. We calculated the upper limits for the number of Jupiter, Saturn-, and Neptune-sized planets in co-planar orbits for different orbital period ranges. We found that there are much fewer giant planets in short periodic orbits around close binary systems than around single stars. Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A117

  5. CRTR-1, a developmentally regulated transcriptional repressor related to the CP2 family of transcription factors.

    Science.gov (United States)

    Rodda, S; Sharma, S; Scherer, M; Chapman, G; Rathjen, P

    2001-02-02

    CP2-related proteins comprise a family of DNA-binding transcription factors that are generally activators of transcription and expressed ubiquitously. We reported a differential display polymerase chain reaction fragment, Psc2, which was expressed in a regulated fashion in mouse pluripotent cells in vitro and in vivo. Here, we report further characterization of the Psc2 cDNA and function. The Psc2 cDNA contained an open reading frame homologous to CP2 family proteins. Regions implicated in DNA binding and oligomeric complex formation, but not transcription activation, were conserved. Psc2 expression in vivo during embryogenesis and in the adult mouse demonstrated tight spatial and temporal regulation, with the highest levels of expression in the epithelial lining of distal convoluted tubules in embryonic and adult kidneys. Functional analysis demonstrated that PSC2 repressed transcription 2.5-15-fold when bound to a heterologous promoter in ES, 293T, and COS-1 cells. The N-terminal 52 amino acids of PSC2 were shown to be necessary and sufficient for this activity and did not share obvious homology with reported repressor motifs. These results represent the first report of a CP2 family member that is expressed in a developmentally regulated fashion in vivo and that acts as a direct repressor of transcription. Accordingly, the protein has been named CP2-Related Transcriptional Repressor-1 (CRTR-1).

  6. Magnetic field distribution and element concentration on the CP2 star CU Virginis

    CERN Document Server

    Glagolevskij, Y V; Hildebrandt, G; Scholz, G; Glagolevskij, Yu.V.

    1998-01-01

    We search for a relation between the published distributions of different elements and the calculated magnetic field structure, following from a dipole-quadrupole configuration, of the CP2 star CU Vir. The highest concentration of individual chemical elements on the stellar surface coincides obviously with the regions of the highest values of the magnetic field strength.

  7. Loss of MeCP2 From Forebrain Excitatory Neurons Leads to Cortical Hyperexcitation and Seizures

    Science.gov (United States)

    Zhang, Wen; Peterson, Matthew; Beyer, Barbara; Frankel, Wayne N.

    2014-01-01

    Mutations of MECP2 cause Rett syndrome (RTT), a neurodevelopmental disorder leading to loss of motor and cognitive functions, impaired social interactions, and seizure at young ages. Defects of neuronal circuit development and function are thought to be responsible for the symptoms of RTT. The majority of RTT patients show recurrent seizures, indicating that neuronal hyperexcitation is a common feature of RTT. However, mechanisms underlying hyperexcitation in RTT are poorly understood. Here we show that deletion of Mecp2 from cortical excitatory neurons but not forebrain inhibitory neurons in the mouse leads to spontaneous seizures. Selective deletion of Mecp2 from excitatory but not inhibitory neurons in the forebrain reduces GABAergic transmission in layer 5 pyramidal neurons in the prefrontal and somatosensory cortices. Loss of MeCP2 from cortical excitatory neurons reduces the number of GABAergic synapses in the cortex, and enhances the excitability of layer 5 pyramidal neurons. Using single-cell deletion of Mecp2 in layer 2/3 pyramidal neurons, we show that GABAergic transmission is reduced in neurons without MeCP2, but is normal in neighboring neurons with MeCP2. Together, these results suggest that MeCP2 in cortical excitatory neurons plays a critical role in the regulation of GABAergic transmission and cortical excitability. PMID:24523563

  8. Apoptotic Activity of MeCP2 Is Enhanced by C-Terminal Truncating Mutations.

    Science.gov (United States)

    Williams, Alison A; Mehler, Vera J; Mueller, Christina; Vonhoff, Fernando; White, Robin; Duch, Carsten

    2016-01-01

    Methyl-CpG binding protein 2 (MeCP2) is a widely abundant, multifunctional protein most highly expressed in post-mitotic neurons. Mutations causing Rett syndrome and related neurodevelopmental disorders have been identified along the entire MECP2 locus, but symptoms vary depending on mutation type and location. C-terminal mutations are prevalent, but little is known about the function of the MeCP2 C-terminus. We employ the genetic efficiency of Drosophila to provide evidence that expression of p.Arg294* (more commonly identified as R294X), a human MECP2 E2 mutant allele causing truncation of the C-terminal domains, promotes apoptosis of identified neurons in vivo. We confirm this novel finding in HEK293T cells and then use Drosophila to map the region critical for neuronal apoptosis to a small sequence at the end of the C-terminal domain. In vitro studies in mammalian systems previously indicated a role of the MeCP2 E2 isoform in apoptosis, which is facilitated by phosphorylation at serine 80 (S80) and decreased by interactions with the forkhead protein FoxG1. We confirm the roles of S80 phosphorylation and forkhead domain transcription factors in affecting MeCP2-induced apoptosis in Drosophila in vivo, thus indicating mechanistic conservation between flies and mammalian cells. Our findings are consistent with a model in which C- and N-terminal interactions are required for healthy function of MeCP2.

  9. MeCP2 in the regulation of neural activity: Rett syndrome pathophysiological perspectives

    Directory of Open Access Journals (Sweden)

    Cuddapah VA

    2015-10-01

    Full Text Available Vishnu Anand Cuddapah,1,* Sinifunanya Elvee Nwaobi,1,* Alan K Percy,2 Michelle Lynne Olsen1 1Department of Cell, Developmental, and Integrative Biology, 2Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, USA *These authors contributed equally to this workAbstract: Rett syndrome (RTT, an X-linked neurodevelopment disorder, occurs in approximately one out of 10,000 females. Individuals afflicted by RTT display a constellation of signs and symptoms, affecting nearly every organ system. Most striking are the neurological manifestations, including regression of language and motor skills, increased seizure activity, autonomic dysfunction, and aberrant regulation of breathing patterns. The majority of girls with RTT have mutations in the gene encoding for methyl-CpG binding protein 2 (MeCP2. Since the discovery of this genetic cause of RTT in 1999, there has been an accelerated pace of research seeking to understand the role of MeCP2 in the brain in the hope of developing a disease-modifying therapy for RTT. In this study, we review the clinical features of RTT and then explore the latest mechanistic studies in order to explain how a mutation in MeCP2 leads to these unique features. We cover in detail studies examining the role of MeCP2 in neuronal physiology, as well as recent evidence that implicates a key role for glia in the pathogenesis of RTT. In the past 20 years, these basic and clinical studies have yielded an extraordinary understanding of RTT; as such, we end this narrative review considering the translation of these studies into clinical trials for the treatment of RTT.Keywords: MeCP2, epigenetic regulation, Rett syndrome, neurons, glia, astrocyte, oligodendrocyte, microglia

  10. Apoptotic Activity of MeCP2 Is Enhanced by C-Terminal Truncating Mutations.

    Directory of Open Access Journals (Sweden)

    Alison A Williams

    Full Text Available Methyl-CpG binding protein 2 (MeCP2 is a widely abundant, multifunctional protein most highly expressed in post-mitotic neurons. Mutations causing Rett syndrome and related neurodevelopmental disorders have been identified along the entire MECP2 locus, but symptoms vary depending on mutation type and location. C-terminal mutations are prevalent, but little is known about the function of the MeCP2 C-terminus. We employ the genetic efficiency of Drosophila to provide evidence that expression of p.Arg294* (more commonly identified as R294X, a human MECP2 E2 mutant allele causing truncation of the C-terminal domains, promotes apoptosis of identified neurons in vivo. We confirm this novel finding in HEK293T cells and then use Drosophila to map the region critical for neuronal apoptosis to a small sequence at the end of the C-terminal domain. In vitro studies in mammalian systems previously indicated a role of the MeCP2 E2 isoform in apoptosis, which is facilitated by phosphorylation at serine 80 (S80 and decreased by interactions with the forkhead protein FoxG1. We confirm the roles of S80 phosphorylation and forkhead domain transcription factors in affecting MeCP2-induced apoptosis in Drosophila in vivo, thus indicating mechanistic conservation between flies and mammalian cells. Our findings are consistent with a model in which C- and N-terminal interactions are required for healthy function of MeCP2.

  11. Time-dependent Corotation Resonance in Barred Galaxies

    Science.gov (United States)

    Wu, Yu-Ting; Pfenniger, Daniel; Taam, Ronald E.

    2016-10-01

    The effective potential neighboring the corotation resonance region in barred galaxies is shown to be strongly time-dependent in any rotating frame, due to the competition of nearby perturbations of similar strengths with differing rotation speeds. Contrary to the generally adopted assumption that in the bar rotating frame the corotation region should possess four stationary equilibrium points (Lagrange points), with high quality N-body simulations, we localize the instantaneous equilibrium points (EPs) and find that they circulate or oscillate broadly in azimuth with respect to the pattern speeds of the inner or outer perturbations. This implies that at the particle level the Jacobi integral is not well conserved around the corotation radius. That is, angular momentum exchanges decouple from energy exchanges, enhancing the chaotic diffusion of stars through the corotation region.

  12. Time-dependent Corotation Resonance in Barred Galaxies

    CERN Document Server

    Wu, Yu-Ting; Taam, Ronald E

    2016-01-01

    The effective potential neighboring the corotation resonance region in barred galaxies is shown to be strongly time-dependent in any rotating frame because of the competition of nearby perturbations of similar strengths with differing rotation speeds. Contrary to the generally adopted assumption, that in the bar rotating frame the corotation region should possess four stationary equilibrium points (Lagrange points), with high quality N-body simulations we localize the instantaneous equilibrium points and find that they circulate or oscillate broadly in azimuth with respect to the pattern speeds of the inner or outer perturbations. This implies that at the particle level the Jacobi integral is not well conserved around the corotation radius. That is, angular momentum exchanges decouple from energy exchanges, enhancing the chaotic diffusion of stars through the corotation region.

  13. Derivation of the parameters of CoRoT planets

    Directory of Open Access Journals (Sweden)

    Dreyer C.

    2013-04-01

    Full Text Available We explore the influence that limb darkening and stellar activity have in the determination of planetary parameters, highlighting the impact that they have in space-based surveys, such as CoRoT.

  14. The variability behavior of CoRoT M-giant Stars

    CERN Document Server

    Lopes, C E Ferreira; Leão, I C; de Freitas, D B; Martins, B L Canto; da Costa, A D; Paz-Chinchón, F; Chagas, M L Das; Baglin, A; Janot-Pacheco, E; De Medeiros, J R

    2015-01-01

    For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and directly opposite from the inner and outer regions of the Galaxy. The high temporal resolution of the CoRoT data combined with the wide time span of the observations has enabled the study of short and long time variations in unprecedented detail. From the initial sample of 2534 stars classified as M-giants in the CoRoT databasis, we selected 1428 targets that exhibit well defined variability, using visual inspection. The variability period and amplitude of C1 stars (stars having Teff < 4200 K) were computed using Lomb-Scargle and harmonic fit methods. The trends found in the V-I vs J-K color-color diagram are in agreement with standard empirical calibrations for M-giants. The sources located towards the inner regions of the Galaxy are distributed throughout the diagram while the majority of the stars towards the outer regions of the G...

  15. The CoRoT Exoplanet program: status & results

    Directory of Open Access Journals (Sweden)

    Moutou C.

    2011-02-01

    Full Text Available The CoRoT satellite is the first instrument hunting for planets from space. We will review the status of the CoRoT/Exoplanet program. We will then present the CoRoT exoplanetary systems and how they widen the range of properties of the close-in population and contribute to our understanding of the properties of planets.

  16. Characterization of bacteriophages Cp1 and Cp2, the strain-typing agents for Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Ahmad, Abdelmonim Ali; Ogawa, Megumi; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    The strains of Xanthomonas axonopodis pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all X. axonopodis pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1(s)) strains have been observed to be resistant to Cp2 (Cp2(r)) and vice versa. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the Siphoviridae. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3'-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of Xanthomonas phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically Escherichia coli T7-like phages of Podoviridae. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of X. axonopodis pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors.

  17. Research progress of the study about the autism and MeCP2 gene%孤独症与MeCP2基因相关性研究进展

    Institute of Scientific and Technical Information of China (English)

    余文珠; 朱水山

    2015-01-01

    研究表明甲基化CpG结合蛋白2(methyl CpG binding protein 2,MeCP2)基因的突变和功能缺失会导致神经系统障碍,有些孤独症患儿中存在MeCP2基因编码区突变.本文根据国内外阐述MeCP2与神经系统疾病的文献,梳理孤独症患儿与MeCP2基因的相关性,探讨MeCP2基因对孤独症发病的影响.

  18. HIV-1 Vpu neutralizes the antiviral factor Tetherin/BST-2 by binding it and directing its beta-TrCP2-dependent degradation.

    Directory of Open Access Journals (Sweden)

    Bastien Mangeat

    2009-09-01

    Full Text Available Host cells impose a broad range of obstacles to the replication of retroviruses. Tetherin (also known as CD317, BST-2 or HM1.24 impedes viral release by retaining newly budded HIV-1 virions on the surface of cells. HIV-1 Vpu efficiently counteracts this restriction. Here, we show that HIV-1 Vpu induces the depletion of tetherin from cells. We demonstrate that this phenomenon correlates with the ability of Vpu to counteract the antiviral activity of both overexpressed and interferon-induced endogenous tetherin. In addition, we show that Vpu co-immunoprecipitates with tetherin and beta-TrCP in a tri-molecular complex. This interaction leads to Vpu-mediated proteasomal degradation of tetherin in a beta-TrCP2-dependent manner. Accordingly, in conditions where Vpu-beta-TrCP2-tetherin interplay was not operative, including cells stably knocked down for beta-TrCP2 expression or cells expressing a dominant negative form of beta-TrCP, the ability of Vpu to antagonize the antiviral activity of tetherin was severely impaired. Nevertheless, tetherin degradation did not account for the totality of Vpu-mediated counteraction against the antiviral factor, as binding of Vpu to tetherin was sufficient for a partial relief of the restriction. Finally, we show that the mechanism used by Vpu to induce tetherin depletion implicates the cellular ER-associated degradation (ERAD pathway, which mediates the dislocation of ER membrane proteins into the cytosol for subsequent proteasomal degradation. In conclusion, we show that Vpu interacts with tetherin to direct its beta-TrCP2-dependent proteasomal degradation, thereby alleviating the blockade to the release of infectious virions. Identification of tetherin binding to Vpu provides a potential novel target for the development of drugs aimed at inhibiting HIV-1 replication.

  19. Permethyl Cobaltocenium (Cp*2Co+) as an Ultra-Stable Cation for Polymer Hydroxide-Exchange Membranes

    Science.gov (United States)

    Gu, Shuang; Wang, Junhua; Kaspar, Robert B.; Fang, Qianrong; Zhang, Bingzi; Bryan Coughlin, E.; Yan, Yushan

    2015-06-01

    Hydroxide (OH-)-exchange membranes (HEMs) are important polymer electrolytes enabling the use of affordable and earth-abundant electrocatalysts for electrochemical energy-conversion devices such as HEM fuel cells, HEM electrolyzers, and HEM solar hydrogen generators. Many HEM cations exist, featuring desirable properties, but new cations are still needed to increase chemical stability at elevated temperatures. Here we introduce the permethyl cobaltocenium [(C5Me5)2Co(III)+ or Cp*2Co+] as an ultra-stable organic cation for polymer HEMs. Compared with the parent cobaltocenium [(C5H5)2Co(III)+ or Cp2Co+], Cp*2Co+ has substantially higher stability and basicity. With polysulfone as an example, we demonstrated the feasibility of covalently linking Cp*2Co+ cation to polymer backbone and prepared Cp*2Co+-functionalized membranes as well. The new cation may be useful in designing more durable HEM electrochemical devices.

  20. Permethyl Cobaltocenium (Cp*2Co+) as an Ultra-Stable Cation for Polymer Hydroxide-Exchange Membranes.

    Science.gov (United States)

    Gu, Shuang; Wang, Junhua; Kaspar, Robert B; Fang, Qianrong; Zhang, Bingzi; Bryan Coughlin, E; Yan, Yushan

    2015-06-29

    Hydroxide (OH(-))-exchange membranes (HEMs) are important polymer electrolytes enabling the use of affordable and earth-abundant electrocatalysts for electrochemical energy-conversion devices such as HEM fuel cells, HEM electrolyzers, and HEM solar hydrogen generators. Many HEM cations exist, featuring desirable properties, but new cations are still needed to increase chemical stability at elevated temperatures. Here we introduce the permethyl cobaltocenium [(C5Me5)2Co(III)(+) or Cp(*)2Co(+)] as an ultra-stable organic cation for polymer HEMs. Compared with the parent cobaltocenium [(C5H5)2Co(III)(+) or Cp2Co(+)], Cp(*)2Co(+) has substantially higher stability and basicity. With polysulfone as an example, we demonstrated the feasibility of covalently linking Cp(*)2Co(+) cation to polymer backbone and prepared Cp(*)2Co(+)-functionalized membranes as well. The new cation may be useful in designing more durable HEM electrochemical devices.

  1. Hydrogen-1 nuclear magnetic resonance of the nitrogenase iron protein (Cp2) from Clostridium pasteurianum.

    Science.gov (United States)

    Meyer, J; Gaillard, J; Moulis, J M

    1988-08-09

    Proton NMR spectra (250 MHz) of the nitrogenase iron protein from Clostridium pasteurianum (Cp2) were found to display 9 or 10 paramagnetically shifted resonances in the 15-50 ppm range. The most shifted resonances belonged to two approximately equal subsets having temperature dependences of opposite sign. The latter occurrence is consistent with the interaction of the corresponding protons with an antiferromagnetically coupled metal center. The number of proton resonances of Cp2, their positions, and their temperature dependences were similar to those observed in spectra of (4Fe-4S)+ ferredoxins, particularly those of the latter that contain a single tetranuclear cluster, such as the ferredoxin from Bacillus stearothermophilus. The effects of several adenine nucleotides on the paramagnetically shifted proton resonances of Cp2 have been investigated. Whereas MgAMP had no effect at all, MgADP and MgATP were found to induce different modifications, which in both cases involved approximately half only of the shifted proton resonances. These data suggest that nucleotide binding affects mainly one part of the iron-sulfur cluster. A remarkable feature of the spectra of Cp2 in the presence of MgATP is the grouping of the shifted proton resonances in sets of two or four having identical chemical shifts and temperature dependences. A nearly perfect 2-fold symmetry is thus suggested for the arrangement of the cysteine protons around the active site. These observations lend support to the proposal that the (4Fe-4S) cluster is held symmetrically between the two identical subunits and are consistent with the existence of two MgATP binding sites on nitrogenase iron proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Isometric immersions of generalized Berger spheres in S4(1) and CP2(4)

    Science.gov (United States)

    Li, Qichao

    2015-12-01

    In this paper, we classify the isometric immersions of generalized Berger spheres (S3, gGB) in S4(1) and CP2(4) (under proper assumption in the latter case) and show the explicit expressions of gGB. As an application, we obtain infinitely many generalized Berger spheres admitting conformal immersions in R4, which is closely related to a question of Peng and Tang (2010).

  3. Characterization of the MeCP2R168X knockin mouse model for Rett syndrome.

    Directory of Open Access Journals (Sweden)

    Eike Wegener

    Full Text Available Rett syndrome, one of the most common causes of mental retardation in females, is caused by mutations in the X chromosomal gene MECP2. Mice deficient for MeCP2 recapitulate some of the symptoms seen in patients with Rett syndrome. It has been shown that reactivation of silent MECP2 alleles can reverse some of the symptoms in these mice. We have generated a knockin mouse model for translational research that carries the most common nonsense mutation in Rett syndrome, R168X. In this article we describe the phenotype of this mouse model. In male MeCP2(R168X mice life span was reduced to 12-14 weeks and bodyweight was significantly lower than in wild type littermates. First symptoms including tremor, hind limb clasping and inactivity occurred at age 27 days. At age 6 weeks nest building, rotarod, open-field and elevated plus maze experiments showed impaired motor performance, reduced activity and decreased anxiety-like behavior. Plethysmography at the same time showed apneas and irregular breathing with reduced frequency. Female MeCP2R168X mice showed no significant abnormalities except decreased performance on the rotarod at age 9 months. In conclusion we show that the male MeCP2(R168X mice have a phenotype similar to that seen in MECP2 knockout mouse models and are therefore well suited for translational research. The female mice, however, have a much milder and less constant phenotype making such research with this mouse model more challenging.

  4. Characterization of the MeCP2R168X knockin mouse model for Rett syndrome.

    Science.gov (United States)

    Wegener, Eike; Brendel, Cornelia; Fischer, Andre; Hülsmann, Swen; Gärtner, Jutta; Huppke, Peter

    2014-01-01

    Rett syndrome, one of the most common causes of mental retardation in females, is caused by mutations in the X chromosomal gene MECP2. Mice deficient for MeCP2 recapitulate some of the symptoms seen in patients with Rett syndrome. It has been shown that reactivation of silent MECP2 alleles can reverse some of the symptoms in these mice. We have generated a knockin mouse model for translational research that carries the most common nonsense mutation in Rett syndrome, R168X. In this article we describe the phenotype of this mouse model. In male MeCP2(R168X) mice life span was reduced to 12-14 weeks and bodyweight was significantly lower than in wild type littermates. First symptoms including tremor, hind limb clasping and inactivity occurred at age 27 days. At age 6 weeks nest building, rotarod, open-field and elevated plus maze experiments showed impaired motor performance, reduced activity and decreased anxiety-like behavior. Plethysmography at the same time showed apneas and irregular breathing with reduced frequency. Female MeCP2R168X mice showed no significant abnormalities except decreased performance on the rotarod at age 9 months. In conclusion we show that the male MeCP2(R168X) mice have a phenotype similar to that seen in MECP2 knockout mouse models and are therefore well suited for translational research. The female mice, however, have a much milder and less constant phenotype making such research with this mouse model more challenging.

  5. Magnetic, chemically peculiar (CP2) stars in the SuperWASP survey

    Science.gov (United States)

    Bernhard, K.; Hümmerich, S.; Paunzen, E.

    2015-12-01

    The magnetic chemically peculiar (CP2) stars of the upper main sequence are well-suited for investigating the impact of magnetic fields on the surface layers of stars, which leads to abundance inhomogeneities (spots) resulting in photometric variability. The light changes are explained in terms of the oblique rotator model; the derived photometric periods thus correlate with the rotational periods of the stars. CP2 stars exhibiting this kind of variability are classified as α2 Canum Venaticorum (ACV) variables. We have analysed around 3 850 000 individual photometric WASP measurements of magnetic chemically peculiar (CP2) stars and candidates selected from the catalogue of Ap, HgMn, and Am stars, with the ultimate goal of detecting new ACV variables. In total, we found 80 variables, from which 74 are reported here for the first time. The data allowed us to establish variability for 23 stars which had been reported as probably constant in the literature before. Light curve parameters were obtained for all stars by a least-squares fit with the fundamental sine wave and its first harmonic. Because of the scarcity of Strömgren uvbyβ measurements and the lack of parallax measurements with an accuracy better than 20%, we are not able to give reliable astrophysical parameters for the investigated objects.

  6. Magnetic, chemically peculiar (CP2) stars in the SuperWASP survey

    CERN Document Server

    Bernhard, K; Paunzen, E

    2015-01-01

    The magnetic chemically peculiar (CP2) stars of the upper main sequence are well-suited for investigating the impact of magnetic fields on the surface layers of stars, which leads to abundance inhomogeneities (spots) resulting in photometric variability. The light changes are explained in terms of the oblique rotator model; the derived photometric periods thus correlate with the rotational periods of the stars. CP2 stars exhibiting this kind of variability are classified as alpha2 Canum Venaticorum (ACV) variables. We have analysed around 3 850 000 individual photometric WASP measurements of magnetic chemically peculiar (CP2) stars and candidates selected from the Catalogue of Ap, HgMn, and Am stars, with the ultimate goal of detecting new ACV variables. In total, we found 80 variables, from which 74 are reported here for the first time. The data allowed us to establish variability for 23 stars which had been reported as probably constant in the literature before. Light curve parameters were obtained for all ...

  7. MeCP2 post-translational modifications: a mechanism to control its involvement in synaptic plasticity and homeostasis?

    Directory of Open Access Journals (Sweden)

    Elisa eBellini

    2014-08-01

    Full Text Available Although Rett syndrome (RTT represents one of the most frequent forms of severe intellectual disability in females worldwide, we still have an inadequate knowledge of the many roles played by MeCP2 (whose mutations are responsible for most cases of RTT and their relevance for RTT pathobiology. Several studies support a role of MeCP2 in the regulation of synaptic plasticity and homeostasis. At the molecular level, MeCP2 is described as a repressor capable of inhibiting gene transcription through chromatin compaction. Indeed, it interacts with several chromatin remodeling factors, such as HDAC-containing complexes and ATRX. Other studies have inferred that MeCP2 functions also as an activator; a role in regulating mRNA splicing and in modulating protein synthesis has also been proposed. Further, MeCP2 avidly binds both 5-methyl- and 5-hydroxymethyl-cytosine. Recent evidence suggests that it is the highly disorganized structure of MeCP2, together with its post-translational modifications (PTMs that generate and regulate this functional versatility. Indeed, several reports have demonstrated that differential phosphorylation of MeCP2 is a key mechanism by which the methyl binding protein modulates its affinity for its partners, gene expression and cellular adaptations to stimuli and neuronal plasticity. As logic consequence, generation of phospho-defective Mecp2 knock-in mice has permitted associating alterations in neuronal morphology, circuit formation, and mouse behavioral phenotypes with specific phosphorylation events. MeCP2 undergoes various other PTMs, including acetylation, ubiquitination and sumoylation, whose functional roles remain largely unexplored. These results, together with the genome-wide distribution of MeCP2 and its capability to substitute histone H1, recall the complex regulation of histones and suggest the relevance of quickly gaining a deeper comprehension of MeCP2 PTMs, the respective writers and readers and the consequent

  8. Finest light curve details, physical parameters, and period fluctuations of CoRoT RR Lyrae stars

    Science.gov (United States)

    Benkő, J. M.; Szabó, R.; Derekas, A.; Sódor, Á.

    2016-12-01

    The CoRoT satellite supplied the scientific community with a huge data base of variable stars. Among them the RR Lyrae stars have intensively been discussed in numerous papers in the last few years, but the latest runs have not been checked to find RR Lyrae stars up to now. Our main goal was to fill this gap and complete the CoRoT RR Lyrae sample. We found nine unstudied RR Lyrae stars. Seven of them are new discoveries. We identified three new Blazhko stars. The Blazhko effect shows non-strictly repetitive nature for all stars. The frequency spectrum of the Blazhko star CoRoT 104948132 contains second overtone frequency with the highest known period ratio. The harmonic amplitude and phase declines with the harmonic order were studied for non-Blazhko stars. We found a period dependent but similar shape amplitude decline for all stars. We discovered significant random period fluctuation for one of the two oversampled target, CM Ori. After a successful transformation of the CoRoT band parameters to the Johnson V values we estimated the basic physical properties such as mass, luminosity, metallicity. The sample can be divided into two subgroups with respect to the metallicity but otherwise the physical parameters are in the canonical range of RR Lyrae stars.

  9. Finest light curve details, physical parameters, and period fluctuations of CoRoT RR Lyrae stars

    CERN Document Server

    Benkő, J M; Derekas, A; Sódor, Á

    2016-01-01

    The CoRoT satellite supplied the scientific community with a huge data base of variable stars. Among them the RR Lyrae stars have intensively been discussed in numerous papers in the last few years, but the latest runs have not been checked to find RR Lyrae stars up to now. Our main goal was to fill this gap and complete the CoRoT RR Lyrae sample. We found nine unstudied RR Lyrae stars. Seven of them are new discoveries. We identified three new Blazhko stars. The Blazhko effect shows non-strictly repetitive nature for all stars. The frequency spectrum of the Blazhko star CoRoT 104948132 contains second overtone frequency with the highest known period ratio. The harmonic amplitude and phase declines with the harmonic order were studied for non-Blazhko stars. We found a period dependent but similar shape amplitude decline for all stars. We discovered significant random period fluctuation for one of the two oversampled target, CM Ori. After a successful transformation of the CoRoT band parameters to the Johnson ...

  10. Chaotic dynamics of corotating magnetospheric convection

    Science.gov (United States)

    Summers, Danny; Mu, Jian-Lin

    1994-01-01

    The corotating plasma convection system of the Jovian magnetosphere is analyzed. The macroscopic (mhd) model introduced by Summers and Mu, (1992) that incorporates the effects of microdiffusion is extended by including previously neglected density effects. We reduce the governing partial differential equations to a third-order ordinary differential system by the Galerkin technique of mode truncation. We carry out such a severe truncation partly in the interests of tractability, and leave open the question of the efficacy of adding additional modes. Exhaustive numerical integrations are carried out to calculate the long-term solutions, and we discover that a rich array of plasma motions is possible, dependent on the value of the height-integrated ionospheric Pederson conductivity Sigma. If Sigma is less than a certain critical value Sigma(sub c), then plasma motion can be expected to be chaotic (or periodic), while if Sigma is greater than Sigma(sub c), then steady state convection is expected. In the former case, whether the plasma motion is chaotic or periodic (and, if periodic, the magnitude of the period) can be very sensitive to the value of Sigma. The value of Sigma(sub c), which is a function of a parameter q that occurs in the assumed form of the stationary radial profile (varies as L(exp -q) of the plasma mass per unit magnetic flux, lies well within the accepted range of values of Sigma for Jupiter, i.e. Sigma greater than or equal to 0.1 mho and less than or equal to 10 mho.

  11. CoRoT: harvest of the exoplanet program

    CERN Document Server

    Moutou, Claire; Guillot, Tristan; Baglin, Annie; Bordé, Pascal; Bouchy, François; Cabrera, Juan; Csizmadia, Szilàrd; Deeg, Hans J

    2013-01-01

    One of the objectives of the CoRoT mission is the search for transiting extrasolar planets using high-precision photometry, and the accurate characterization of their fundamental parameters. The CoRoT satellite consecutively observes crowded stellar fields since February 2007, in high-cadence precise photometry; periodic eclipses are detected and analysed in the stellar light curves. Then complementary observations using ground-based facilities allows establishing the nature of the transiting body and its mass. CoRoT has acquired more than 163,000 light curves and detected about 500 planet candidates. A fraction of them (5%) are confirmed planets whose masses are independently measured. Main highlights of the CoRoT discoveries are: i) the variety of internal structures in close-in giant planets, ii) the characterisation of the first known transiting rocky planet, CoRoT-7 b, iii) multiple constraints on the formation, evolution, role of tides in planetary systems.

  12. Correlation of abnormal DNMT1 and MeCP2 expression with cell biological characteristics in cervical lesion tissue

    Institute of Scientific and Technical Information of China (English)

    Wei Lin; Sha Ma

    2016-01-01

    Objective:To study the correlation of abnormal DNMT1 and MeCP2 expression with cell biological characteristics in cervical lesion tissue.Methods:Cervical cancer tissue and para-carcinoma tissue were collected from cervical cancer patients who received surgery in our hospital from May 2012 to October 2015, and HPV types as well as the expression levels of DNMTs, MeCP2, PBK, TOPK, Snail, Slug, SALL4 and Cat L were determined.Results:Protein levels of DNMT1, DNMT2, DNMT3a, DNMT3b, DNMT3l and MeCP2 in cervical cancer tissue were significantly higher than those in para-carcinoma tissue, and the rising trend of DNMT1 expression level was the most significant; protein levels of DNMT1, DNMT2, DNMT3a, DNMT3b, DNMT3l and MeCP2 in cervical cancer tissue with high-risk HPV infection were significantly higher than those in cervical cancer tissue with normal HPV infection; in cervical cancer tissue with high expression of DNMT1 and MeCP2, PBK, TOPK, Snail, Slug, SALL4 and Cat L levels were significantly higher than those in cervical cancer tissue with low expression of DNMT1 and MeCP2.Conclusions:Abnormally high expression of DNMT1 and MeCP2 in cervical cancer tissue may up-regulate the expression of a variety of malignant biological molecules by increasing methylation level.

  13. Recombinant phytochrome of the moss Ceratodon purpureus (CP2): fluorescence spectroscopy and photochemistry.

    Science.gov (United States)

    Sineshchekov, V; Koppel, L; Hughes, J; Lamparter, T; Zeidler, M

    2000-07-01

    The recombinant phytochrome of the moss Ceratodon purpureus (CP2) expressed in Saccharomyces cerevisiae and reconstituted with phycocyanobilin (PCB) was investigated using fluorescence spectroscopy. The pigment had an emission maximum at 670 nm at low temperature (85 K) and at 667 nm at room temperature (RT) and an excitation maximum at 650-652 nm at 85 K (excitation spectra could not be measured at RT). Both spectra had a half-band width of approx. 30-35 nm at 85 K. The fluorescence intensity revealed a steep temperature dependence with an activation energy of fluorescence decay (Ea) of 5.9-6.4 and 12.6-14.7 kJ mol(-1) in the interval from 85 to 210 K and from 210 to 275 K, respectively. The photochemical properties of CP2/PCB were characterised by the extent of the red-induced (lambda(a) = 639 nm) Pr conversion into the first photoproduct lumi-R at 85 K (gamma1) of approximately 0.07 and into Pfr at RT (gamma2) of approximately 0.7. From these characteristics, CP2/PCB can be attributed to the Pr" photochemical type with gamma1 < or = 0.05, which comprises the minor phyA fraction (phyA"), phyB, Adiantum phy1 and Synechocystis Cph1 in contrast to the major phyA' fraction (Pr' type with gamma1 = 0.5). Within the Pr" type, it is closer to phyA" than to phyB and Cph1.

  14. Gauge-invariant functional measure for gauge fields on CP2

    Science.gov (United States)

    Nair, V. P.

    2013-11-01

    We introduce a general parametrization for non-Abelian gauge fields on the four-dimensional space CP2. The volume element for the gauge-orbit space or the space of physical configurations is then investigated. The leading divergence in this volume element is obtained in terms of a higher dimensional Wess-Zumino-Witten action, which has previously been studied in the context of Kähler-Chern-Simons theories. This term, it is argued, implies that one needs to introduce a dimensional parameter to specify the integration measure, a step which is a nonperturbative version of the well-known dimensional transmutation in four-dimensional gauge theories.

  15. An abundance study of the red giants in the seismology fields of the CoRoT satellite

    CERN Document Server

    Morel, T; Lagarde, N; Montalban, J; Rainer, M; Poretti, E; Hekker, S; Kallinger, T; Mosser, B; Valentini, M; Carrier, F; Hareter, M; Mantegazza, L; De Ridder, J

    2012-01-01

    A precise characterisation of the red giants in the seismology fields of the CoRoT satellite is a prerequisite for further in-depth seismic modelling. The optical spectra obtained for 19 targets have been used to accurately estimate their fundamental parameters and chemical composition. The extent of internal mixing is also investigated through the abundances of Li, CNO and Na (as well as 12C/13C in a few cases).

  16. Revised Conditions for MRI due to Corotation Theorem

    CERN Document Server

    Cianfrani, Francesco

    2016-01-01

    We re-analyze the physical conditions for Magneto-rotational Instability (MRI) within a steady axisymmetric stratified disk of plasma, in order to account for the so-called corotation theory (the differential angular velocity depends on the magnetic flux surface). We develop the study of linear stability around an astrophysical background configuration, following the original derivation in \\cite{Ba:1995}, but implementing the corotation condition as the orthogonality between the background magnetic field and the angular velocity gradient. We demonstrate that a dependence on the background magnetic field direction is restored in the dispersion relation and, hence, the emergence of MRI is affected too.

  17. Trace Conserving Purification for Linear Scaling [O(N)] Methods: A First Enhancement to CP2K

    Science.gov (United States)

    2014-09-01

    purification scheme times in CP2K. Timings are normalized to TRS4 for each band gap. 5 Fig. 2 Graphical representation of the 1024 water box...Trace Conserving Purification for Linear Scaling [O(N)] Methods: A First Enhancement to CP2K by Jonathan Mullin ARL-CR-0746 September...Proving Ground, MD 21005-5069 ARL-CR-0746 September 2014 Trace Conserving Purification for Linear Scaling [O(N)] Methods: A First

  18. MeCP2 Affects Skeletal Muscle Growth and Morphology through Non Cell-Autonomous Mechanisms.

    Directory of Open Access Journals (Sweden)

    Valentina Conti

    Full Text Available Rett syndrome (RTT is an autism spectrum disorder mainly caused by mutations in the X-linked MECP2 gene and affecting roughly 1 out of 10.000 born girls. Symptoms range in severity and include stereotypical movement, lack of spoken language, seizures, ataxia and severe intellectual disability. Notably, muscle tone is generally abnormal in RTT girls and women and the Mecp2-null mouse model constitutively reflects this disease feature. We hypothesized that MeCP2 in muscle might physiologically contribute to its development and/or homeostasis, and conversely its defects in RTT might alter the tissue integrity or function. We show here that a disorganized architecture, with hypotrophic fibres and tissue fibrosis, characterizes skeletal muscles retrieved from Mecp2-null mice. Alterations of the IGF-1/Akt/mTOR pathway accompany the muscle phenotype. A conditional mouse model selectively depleted of Mecp2 in skeletal muscles is characterized by healthy muscles that are morphologically and molecularly indistinguishable from those of wild-type mice raising the possibility that hypotonia in RTT is mainly, if not exclusively, mediated by non-cell autonomous effects. Our results suggest that defects in paracrine/endocrine signaling and, in particular, in the GH/IGF axis appear as the major cause of the observed muscular defects. Remarkably, this is the first study describing the selective deletion of Mecp2 outside the brain. Similar future studies will permit to unambiguously define the direct impact of MeCP2 on tissue dysfunctions.

  19. MeCP2 Affects Skeletal Muscle Growth and Morphology through Non Cell-Autonomous Mechanisms.

    Science.gov (United States)

    Conti, Valentina; Gandaglia, Anna; Galli, Francesco; Tirone, Mario; Bellini, Elisa; Campana, Lara; Kilstrup-Nielsen, Charlotte; Rovere-Querini, Patrizia; Brunelli, Silvia; Landsberger, Nicoletta

    2015-01-01

    Rett syndrome (RTT) is an autism spectrum disorder mainly caused by mutations in the X-linked MECP2 gene and affecting roughly 1 out of 10.000 born girls. Symptoms range in severity and include stereotypical movement, lack of spoken language, seizures, ataxia and severe intellectual disability. Notably, muscle tone is generally abnormal in RTT girls and women and the Mecp2-null mouse model constitutively reflects this disease feature. We hypothesized that MeCP2 in muscle might physiologically contribute to its development and/or homeostasis, and conversely its defects in RTT might alter the tissue integrity or function. We show here that a disorganized architecture, with hypotrophic fibres and tissue fibrosis, characterizes skeletal muscles retrieved from Mecp2-null mice. Alterations of the IGF-1/Akt/mTOR pathway accompany the muscle phenotype. A conditional mouse model selectively depleted of Mecp2 in skeletal muscles is characterized by healthy muscles that are morphologically and molecularly indistinguishable from those of wild-type mice raising the possibility that hypotonia in RTT is mainly, if not exclusively, mediated by non-cell autonomous effects. Our results suggest that defects in paracrine/endocrine signaling and, in particular, in the GH/IGF axis appear as the major cause of the observed muscular defects. Remarkably, this is the first study describing the selective deletion of Mecp2 outside the brain. Similar future studies will permit to unambiguously define the direct impact of MeCP2 on tissue dysfunctions.

  20. Correction for small satellite motion on the COROT asteroseismology channel

    NARCIS (Netherlands)

    Drummond, R.; Oliveira Fialho, F. de; Vandenbussche, B.; Auvergne, M.; Aerts, C.C.

    2006-01-01

    The COROT satellite contains a highly accurate stellar photometer with two channels that are respectively optimized for asteroseismology and terrestrial planet finding. The asteroseismology channel can observe 10 bright objects per field for 150 days (long run). At least five different long-run fiel

  1. GAUDI: A Preparatory Archive for the COROT Mission

    NARCIS (Netherlands)

    Aerts, C.C.

    2005-01-01

    The GAUDI database (Ground-based Asteroseismology Uniform Database Interface) is a preparatory archive for the COROT (Convection, Rotation, and Planetary Transits) mission developed at the Laboratorio de Astrofísica Espacial y Física Fundamental (Laboratory for Space Astrophysics and Theoretical

  2. Formation of plasmasphere in the non-ideal corotation field

    Science.gov (United States)

    Dumin, Yurii

    It is well-known that the standard model of plasmasphere formation by the combined action of convection and the ideal corotation fields is too simplified and does not describe some important features. One of attempts to improve it was undertaken a few years ago in our paper [1], where we considered generation of the corotation field in the strongly-anisotropic magnetospheric plasma and took into account distortion of this field in high latitudes due to escape of the polarization charges along the open magnetic field lines. In the present report, we further develop the idea of refinement of the corotation field, particularly, by the consideration of the magnetic dipole inclined with respect to the rotation axis. It will be shown that all the above-mentioned improvements result in the more adequate description of the position of plasmapause both in the quiet and disturbed conditions. References: 1. Yu.V. Dumin. The Corotation Field in Collisionless Magnetospheric Plasma and Its Influence on Average Electric Field in the Lower Atmosphere. Advances in Space Research, v.30, p.2209 (2002).

  3. News from the CoRoT Space Mission

    CERN Document Server

    Dvorak, R; Lammer, H; Barge, P; Wuchterl, G

    2009-01-01

    The up to 150 day uninterrupted high-precision photometry of about 100000 stars - provided so far by the exoplanet channel of the CoRoT space telescope - gave a new perspective on the planet population of our galactic neighbourhood. The seven planets with very accurate parameters widen the range of known planet properties in almost any respect. Giant planets have been detected at low metallicity, rapidly rotating and active, spotted stars. CoRoT-3 populated the brown dwarf desert and closed the gap of measured physical properties between standard giant planets and very low mass stars. CoRoT extended the known range of planet masses down to 5 Earth masses and up to 21 Jupiter masses, the radii to less than 2 Earth radii and up to the most inflated hot Jupiter found so far, and the periods of planets discovered by transits to 9 days. Two CoRoT planets have host stars with the lowest content of heavy elements known to show a transit hinting towards a different planet-host-star-metallicity relation then the one f...

  4. Detection of small-size planetary candidates with CoRoT data

    Directory of Open Access Journals (Sweden)

    Moutou C.

    2011-02-01

    Full Text Available With the discovery of CoRoT-7b, the first transiting super-Earth, the CoRoT space mission has shown the capability to detect short-period rocky planets around solar-like stars. By performing a blind test with real CoRoT light curves, we want to establish the detection threshold of small-size planets in CoRoT data. We investigate the main obstacles to the detection of transiting super-Earths in CoRoT data, notably the presence of short-time scale variability and hot pixels.

  5. Low-amplitude rotational modulation rather than pulsations in the CoRoT B-type supergiant HD 46769

    CERN Document Server

    Aerts, C; Catala, C; Neiner, C; Briquet, M; Castro, N; Schmid, V S; Scardia, M; Rainer, M; Poretti, E; Papics, I; Degroote, P; Bloemen, S; Oestensen, R H; Auvergne, M; Baglin, A; Baudin, F; Michel, E; Samadi, R

    2013-01-01

    {We aim to detect and interpret photometric and spectroscopic variability of the bright CoRoT B-type supergiant target HD\\,46769 ($V=5.79$). We also attempt to detect a magnetic field in the target.} {We analyse a 23-day oversampled CoRoT light curve after detrending, as well as spectroscopic follow-up data, by using standard Fourier analysis and Phase Dispersion Minimization methods. We determine the fundamental parameters of the star, as well as its abundances from the most prominent spectral lines. We perform a Monte Carlo analysis of spectropolarimetric data to obtain an upper limit of the polar magnetic field, assumping a dipole field.} {In the CoRoT data, we detect a dominant period of 4.84\\,d with an amplitude of 87\\,ppm, and some of its (sub-)multiples. Given the shape of the phase-folded light curve and the absence of binary motion, we interpret the dominant variability in terms of rotational modulation, with a rotation period of 9.69\\,d. Subtraction of the rotational modulation signal does not revea...

  6. Autism-like behaviours and germline transmission in transgenic monkeys overexpressing MeCP2.

    Science.gov (United States)

    Liu, Zhen; Li, Xiao; Zhang, Jun-Tao; Cai, Yi-Jun; Cheng, Tian-Lin; Cheng, Cheng; Wang, Yan; Zhang, Chen-Chen; Nie, Yan-Hong; Chen, Zhi-Fang; Bian, Wen-Jie; Zhang, Ling; Xiao, Jianqiu; Lu, Bin; Zhang, Yue-Fang; Zhang, Xiao-Di; Sang, Xiao; Wu, Jia-Jia; Xu, Xiu; Xiong, Zhi-Qi; Zhang, Feng; Yu, Xiang; Gong, Neng; Zhou, Wen-Hao; Sun, Qiang; Qiu, Zilong

    2016-02-04

    Methyl-CpG binding protein 2 (MeCP2) has crucial roles in transcriptional regulation and microRNA processing. Mutations in the MECP2 gene are found in 90% of patients with Rett syndrome, a severe developmental disorder with autistic phenotypes. Duplications of MECP2-containing genomic segments cause the MECP2 duplication syndrome, which shares core symptoms with autism spectrum disorders. Although Mecp2-null mice recapitulate most developmental and behavioural defects seen in patients with Rett syndrome, it has been difficult to identify autism-like behaviours in the mouse model of MeCP2 overexpression. Here we report that lentivirus-based transgenic cynomolgus monkeys (Macaca fascicularis) expressing human MeCP2 in the brain exhibit autism-like behaviours and show germline transmission of the transgene. Expression of the MECP2 transgene was confirmed by western blotting and immunostaining of brain tissues of transgenic monkeys. Genomic integration sites of the transgenes were characterized by a deep-sequencing-based method. As compared to wild-type monkeys, MECP2 transgenic monkeys exhibited a higher frequency of repetitive circular locomotion and increased stress responses, as measured by the threat-related anxiety and defensive test. The transgenic monkeys showed less interaction with wild-type monkeys within the same group, and also a reduced interaction time when paired with other transgenic monkeys in social interaction tests. The cognitive functions of the transgenic monkeys were largely normal in the Wisconsin general test apparatus, although some showed signs of stereotypic cognitive behaviours. Notably, we succeeded in generating five F1 offspring of MECP2 transgenic monkeys by intracytoplasmic sperm injection with sperm from one F0 transgenic monkey, showing germline transmission and Mendelian segregation of several MECP2 transgenes in the F1 progeny. Moreover, F1 transgenic monkeys also showed reduced social interactions when tested in pairs, as

  7. Exploring the possible link between MeCP2 and oxidative stress in Rett syndrome.

    Science.gov (United States)

    Filosa, Stefania; Pecorelli, Alessandra; D'Esposito, Maurizio; Valacchi, Giuseppe; Hajek, Joussef

    2015-11-01

    Rett syndrome (RTT, MIM 312750) is a rare and orphan progressive neurodevelopmental disorder affecting girls almost exclusively, with a frequency of 1/15,000 live births of girls. The disease is characterized by a period of 6 to 18 months of apparently normal neurodevelopment, followed by early neurological regression, with a progressive loss of acquired cognitive, social, and motor skills. RTT is known to be caused in 95% of the cases by sporadic de novo loss-of-function mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene encoding methyl-CpG binding protein 2 (MeCP2), a nuclear protein able to regulate gene expression. Despite almost two decades of research into the functions and role of MeCP2, little is known about the mechanisms leading from MECP2 mutation to the disease. Oxidative stress (OS) is involved in the pathogenic mechanisms of several neurodevelopmental and neurodegenerative disorders, although in many cases it is not clear whether OS is a cause or a consequence of the pathology. Fairly recently, the presence of a systemic OS has been demonstrated in RTT patients with a strong correlation with the patients' clinical status. The link between MECP2 mutation and the redox imbalance found in RTT is not clear. Animal studies have suggested a possible direct correlation between Mecp2 mutation and increased OS levels. In addition, the restoration of Mecp2 function in astrocytes significantly improves the developmental outcome of Mecp2-null mice and reexpression of Mecp2 gene in the brain of null mice restored oxidative damage, suggesting that Mecp2 loss of function can be involved in oxidative brain damage. Starting from the evidence that oxidative damage in the brain of Mecp2-null mice precedes the onset of symptoms, we evaluated whether, based on the current literature, the dysfunctions described in RTT could be a consequence or, in contrast, could be caused by OS. We also analyzed whether therapies that at least partially treated some RTT

  8. Ligand-Controlled CO2 Activation Mediated by Cationic Titanium Hydride Complexes, [LTiH](+) (L=Cp2 , O).

    Science.gov (United States)

    Tang, Shi-Ya; Rijs, Nicole J; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2015-06-01

    CO2 activation mediated by [LTiH](+) (L=Cp2 , O) is observed in the gas phase at room temperature using electrospray-ionization mass spectrometry, and reaction details are derived from traveling wave ion-mobility mass spectrometry. Wheresas oxygen-atom transfer prevails in the reaction of the oxide complex [OTiH](+) with CO2 , generating [OTi(OH)](+) under the elimination of CO, insertion of CO2 into the metal-hydrogen bond of the cyclopentadienyl complex, [Cp2 TiH](+) , gives rise to the formate complex [Cp2 Ti(O2 CH)](+) . DFT-based methods were employed to understand how the ligand controls the observed variation in reactivity toward CO2 . Insertion of CO2 into the Ti-H bond constitutes the initial step for the reaction of both [Cp2 TiH](+) and [OTiH](+) , thus generating formate complexes as intermediates. In contrast to [Cp2 Ti(O2 CH)](+) which is kinetically stable, facile decarbonylation of [OTi(O2 CH)](+) results in the hydroxo complex [OTi(OH)](+) . The longer lifetime of [Cp2 Ti(O2 CH)](+) allows for secondary reactions with background water, as a result of which, [Cp2 Ti(OH)](+) is formed. Further, computational studies reveal a good linear correlation between the hydride affinity of [LTi](2+) and the barrier for CO2 insertion into various [LTiH](+) complexes. Understanding the intrinsic ligand effects may provide insight into the selective activation of CO2 .

  9. Proposal for the Quantum Simulation of the CP(2) Model on Optical Lattices

    CERN Document Server

    Laflamme, Catherine; Dalmonte, Marcello; Gerber, Urs; Mejía-Díaz, Héctor; Bietenholz, Wolfgang; Wiese, Uwe-Jens; Zoller, Peter

    2015-01-01

    The 2d CP(N-1) models share a number of features with QCD, like asymptotic freedom, a dynamically generated mass gap and topological sectors. They have been formulated and analysed successfully in the framework of the so-called D-theory, which provides a smooth access to the continuum limit. In that framework, we propose an experimental set-up for the quantum simulation of the CP(2) model. It is based on ultra-cold Alkaline-Earth Atoms (AEAs) located on the sites of an optical lattice, where the nuclear spins represent the relevant degrees of freedom. We present numerical results for the correlation length and for the real time decay of a false vacuum, to be compared with such a future experiment. The latter could also enable the exploration of theta-vacua and of the phase diagram at finite chemical potentials, since it does not suffer from any sign problem.

  10. Topological first-order vortices in a gauged CP(2 model

    Directory of Open Access Journals (Sweden)

    R. Casana

    2017-05-01

    Full Text Available We study time-independent radially symmetric first-order solitons in a CP(2 model interacting with an Abelian gauge field whose dynamics is controlled by the usual Maxwell term. In this sense, we develop a consistent first-order framework verifying the existence of a well-defined lower bound for the corresponding energy. We saturate such a lower bound by focusing on those solutions satisfying a particular set of coupled first-order differential equations. We solve these equations numerically using appropriate boundary conditions giving rise to regular structures possessing finite-energy. We also comment the main features these configurations exhibit. Moreover, we highlight that, despite the different solutions we consider for an auxiliary function β(r labeling the model (therefore splitting our investigation in two a priori distinct branches, all resulting scenarios engender the very same phenomenology, being physically equivalent.

  11. Topological first-order vortices in a gauged CP(2) model

    Science.gov (United States)

    Casana, R.; Dias, M. L.; da Hora, E.

    2017-05-01

    We study time-independent radially symmetric first-order solitons in a CP (2) model interacting with an Abelian gauge field whose dynamics is controlled by the usual Maxwell term. In this sense, we develop a consistent first-order framework verifying the existence of a well-defined lower bound for the corresponding energy. We saturate such a lower bound by focusing on those solutions satisfying a particular set of coupled first-order differential equations. We solve these equations numerically using appropriate boundary conditions giving rise to regular structures possessing finite-energy. We also comment the main features these configurations exhibit. Moreover, we highlight that, despite the different solutions we consider for an auxiliary function β (r) labeling the model (therefore splitting our investigation in two a priori distinct branches), all resulting scenarios engender the very same phenomenology, being physically equivalent.

  12. The ADHM-like constructions for instantons on CP2 and three-dimensional gauge theories

    Science.gov (United States)

    Mekareeya, Noppadol; Rodríguez-Gómez, Diego

    2015-02-01

    We study the moduli spaces of self-dual instantons on CP2 in a simple group G. When G is a classical group, these instanton solutions can be realized using ADHM-like constructions which can be naturally embedded into certain three-dimensional quiver gauge theories with four supercharges. The topological data for such instanton bundles and their relations to the quiver gauge theories are described. Based on such gauge theory constructions, we compute the Hilbert series of the moduli spaces of instantons that correspond to various configurations. The results turn out to be equal to the Hilbert series of their counterparts on C2 upon an appropriate mapping. We check the former against the Hilbert series derived from the blowup formula for the Hirzebruch surface F1 and find an agreement. The connection between the moduli spaces of instantons on such two spaces is explained in detail.

  13. Statistics on the spectral classification of CP2 stars in the Southern Sky

    CERN Document Server

    Rode, M; Paunzen, E

    1998-01-01

    A number of about 1500 spectroscopically classified CP2 stars in the southern sky (delta =-90 to -12 degrees) was extracted from the Michigan Catalogue (Vols. I - IV). This sample was compared with the classification from Bidelman & Mc Connell (1973). We confirmed the spectral classification with the known photometric peculiarity indices in the Geneva system and in the 3-filter Delta a system (Maitzen 1976). 10% of these stars show discordance between their respective types from the Michigan and Bidelman catalogues. Several objects were measured with a CCD in the Delta a system in spring 1995. Eight stars are peculiar in Delta a. Furthermore, we have investigated the galactic distribution of all programme stars. We conclude that the distribution resembles the one of early-type stars, where the hotter (= Silicon) stars are more concentrated towards the galactic plane than the cooler (= Strontium) objects.

  14. Resurgent Transseries and the Holomorphic Anomaly: Nonperturbative Closed Strings in Local CP2

    CERN Document Server

    Couso-Santamaría, Ricardo; Schiappa, Ricardo; Vonk, Marcel

    2015-01-01

    The holomorphic anomaly equations describe B-model closed topological strings in Calabi-Yau geometries. Having been used to construct perturbative expansions, it was recently shown that they can also be extended past perturbation theory by making use of resurgent transseries. These yield formal nonperturbative solutions, showing integrability of the holomorphic anomaly equations at the nonperturbative level. This paper takes such constructions one step further by working out in great detail the specific example of topological strings in the mirror of the local CP2 toric Calabi-Yau background, and by addressing the associated (resurgent) large-order analysis of both perturbative and multi-instanton sectors. In particular, analyzing the asymptotic growth of the perturbative free energies, one finds contributions from three different instanton actions related by Z_3 symmetry, alongside another action related to the Kahler parameter. Resurgent transseries methods then compute, from the extended holomorphic anomal...

  15. The ADHM-like constructions for instantons on CP2 and three-dimensional gauge theories

    Directory of Open Access Journals (Sweden)

    Noppadol Mekareeya

    2015-02-01

    Full Text Available We study the moduli spaces of self-dual instantons on CP2 in a simple group G. When G is a classical group, these instanton solutions can be realized using ADHM-like constructions which can be naturally embedded into certain three-dimensional quiver gauge theories with four supercharges. The topological data for such instanton bundles and their relations to the quiver gauge theories are described. Based on such gauge theory constructions, we compute the Hilbert series of the moduli spaces of instantons that correspond to various configurations. The results turn out to be equal to the Hilbert series of their counterparts on C2 upon an appropriate mapping. We check the former against the Hilbert series derived from the blowup formula for the Hirzebruch surface F1 and find an agreement. The connection between the moduli spaces of instantons on such two spaces is explained in detail.

  16. Epigenetic silencing of the proapoptotic gene BIM in anaplastic large cell lymphoma through an MeCP2/SIN3a deacetylating complex.

    Science.gov (United States)

    Piazza, Rocco; Magistroni, Vera; Mogavero, Angela; Andreoni, Federica; Ambrogio, Chiara; Chiarle, Roberto; Mologni, Luca; Bachmann, Petra S; Lock, Richard B; Collini, Paola; Pelosi, Giuseppe; Gambacorti-Passerini, Carlo

    2013-05-01

    BIM is a proapoptotic member of the Bcl-2 family. Here, we investigated the epigenetic status of the BIM locus in NPM/ALK+ anaplastic large cell lymphoma (ALCL) cell lines and in lymph node biopsies from NPM/ALK+ ALCL patients. We show that BIM is epigenetically silenced in cell lines and lymph node specimens and that treatment with the deacetylase inhibitor trichostatin A restores the histone acetylation, strongly upregulates BIM expression, and induces cell death. BIM silencing occurs through recruitment of MeCP2 and the SIN3a/histone deacetylase 1/2 (HDAC1/2) corepressor complex. This event requires BIM CpG methylation/demethylation with 5-azacytidine that leads to detachment of the MeCP2 corepressor complex and reacetylation of the histone tails. Treatment with the ALK inhibitor PF2341066 or with an inducible shRNA targeting NPM/ALK does not restore BIM locus reacetylation; however, enforced expression of NPM/ALK in an NPM/ALK-negative cell line significantly increases the methylation at the BIM locus. This study demonstrates that BIM is epigenetically silenced in NPM/ALK-positive cells through recruitment of the SIN3a/HDAC1/2 corepressor complex and that NPM/ALK is dispensable to maintain BIM epigenetic silencing but is able to act as an inducer of BIM methylation.

  17. Epigenetic Silencing of the Proapoptotic Gene BIM in Anaplastic Large Cell Lymphoma through an MeCP2/SIN3a Deacetylating Complex

    Directory of Open Access Journals (Sweden)

    Rocco Piazza

    2013-05-01

    Full Text Available BIM is a proapoptotic member of the Bcl-2 family. Here, we investigated the epigenetic status of the BIM locus in NPM/ALK+ anaplastic large cell lymphoma (ALCL cell lines and in lymph node biopsies from NPM/ALK+ ALCL patients. We show that BIM is epigenetically silenced in cell lines and lymph node specimens and that treatment with the deacetylase inhibitor trichostatin A restores the histone acetylation, strongly upregulates BIM expression, and induces cell death. BIM silencing occurs through recruitment of MeCP2 and the SIN3a/histone deacetylase 1/2 (HDAC1/2 corepressor complex. This event requires BIM CpG methylation/demethylation with 5-azacytidine that leads to detachment of the MeCP2 corepressor complex and reacetylation of the histone tails. Treatment with the ALK inhibitor PF2341066 or with an inducible shRNA targeting NPM/ALK does not restore BIM locus reacetylation; however, enforced expression of NPM/ALK in an NPM/ALK-negative cell line significantly increases the methylation at the BIM locus. This study demonstrates that BIM is epigenetically silenced in NPM/ALK-positive cells through recruitment of the SIN3a/HDAC1/2 corepressor complex and that NPM/ALK is dispensable to maintain BIM epigenetic silencing but is able to act as an inducer of BIM methylation.

  18. Transiting exoplanets from the CoRoT space mission . XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit

    DEFF Research Database (Denmark)

    Rouan, D.; Parviainen, H.; Moutou, C.

    2012-01-01

    We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 ± 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric sear...

  19. Transiting exoplanets from the CoRoT space mission . XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit

    DEFF Research Database (Denmark)

    Rouan, D.; Parviainen, H.; Moutou, C.

    2012-01-01

    We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 ± 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric sear...

  20. Transiting exoplanets from the CoRoT space mission. XXIII. CoRoT-21b: a doomed large Jupiter around a faint subgiant star

    DEFF Research Database (Denmark)

    Pätzold, M.; Endl, M.; Csizmadia, Sz.;

    2012-01-01

    CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observ...

  1. GAUDI: a preparatory archive for the COROT mission

    CERN Document Server

    Solano, E; Garrido, R; Poretti, E; Janot-Pacheco, E; Gutíerrez, R; González, R; Mantegazza, L; Neiner, C; Frémat, Y; Charpinet, S; Weiss, W; Amado, P J; Rainer, M; Tsymbal, V V; Lyashko, D; Ballereau, D; Bouret, J C; Hua, T; Katz, D; Lignières, F; Lüftinger, T; Mittermayer, P; Nesvacil, N; Soubiran, C; Veer-Menneret, C V; Goupil, M J; Costa, V; Rolland, A; Antonello, E; Bossi, M; Buzzoni, A; Rodrigo, C; Aerts, C; Butler, C J; Günther, E; Hatzes, A

    2004-01-01

    The GAUDI database (Ground-based Asteroseismology Uniform Database Interface, http://sdc.laeff.esa.es/gaudi/) is a preparatory archive for the COROT (COnvection, ROtation and planetary Transits, http://www.astrsp-mrs.fr/projets/corot/) mission developed at LAEFF (Laboratory for Space Astrophysics and Theoretical Physics, http://www.laeff.esa.es). Its intention is to make the ground-based observations obtained in the preparation of the asteroseismology programme available in a simple and efficient way. It contains spectroscopic and photometric data together with inferred physical parameters for more than 1500 objects gathered since January 1998 in 6 years of observational campaigns. In this paper, the main functionalities and characteristics of the system are described. The observations have been collected at ESO-La Silla, Telescopio Nazionale Galileo, Observatoire de Haute-Provence, South African Astronomical Observatory, Tautenberg Observatory and Sierra Nevada Observatory.

  2. Transiting exoplanets from the CoRoT space mission

    DEFF Research Database (Denmark)

    Ollivier, M.; Gillon, M.; Santerne, A.

    2012-01-01

    Aims. We report the discovery of CoRoT-16b, a low density hot jupiter that orbits a faint G5V star (mV = 15.63) in 5.3523 ± 0.0002 days with slight eccentricity. A fit of the data with no a priori assumptions on the orbit leads to an eccentricity of 0.33 ± 0.1. We discuss this value and also deri...

  3. THE MASS OF CoRoT-7b

    Energy Technology Data Exchange (ETDEWEB)

    Hatzes, Artie P.; Wuchterl, Guenther [Thueringer Landessternwarte, D-07778 Tautenburg (Germany); Fridlund, Malcolm; Gandolfi, Davide [European Space Agency, ESTEC, SRE-SA, P.O. Box 299, NL-2200AG, Noordwijk (Netherlands); Nachmani, Gil; Mazeh, Tsevi [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv (Israel); Valencia, Diana [Observatoire de la Cote d' Azur, BP 4229, F-06304 Nice Cedex 4 (France); Hebrard, Guillaume; Borde, Pascal [Institut d' Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre and Marie Curie, 98bis boulevard Arago, F-75014 Paris (France); Carone, Ludmila; Paetzold, Martin [Rheinisches Institut fuer Umweltforschung, Universitaet zu Koeln, Abt. Planetenforschung, Aachener Str. 209, D-50931 Koeln (Germany); Udry, Stephane [Observatoire de l' Universite de Geneve, 51 chemin des Maillettes, 1290 Sauverny (Switzerland); Bouchy, Francois [Observatoire de Haute Provence, F-04670 Saint Michel l' Observatoire (France); Deleuil, Magali; Moutou, Claire; Barge, Pierre [Laboratoire d' Astrophysique de Marseille, CNRS and University of Provence, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France); Deeg, Hans; Tingley, Brandon [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Dvorak, Rudolf [University of Vienna, Institute of Astronomy, Tuerkenschanzstr. 17, A-1180, Vienna (Austria); Ferraz-Mello, Sylvio, E-mail: artie@tls-tautenburg.de, E-mail: malcolm.fridlund@esa.int [IAG, University of Sao Paulo (Brazil); and others

    2011-12-10

    The mass of CoRoT-7b, the first transiting super-Earth exoplanet, is still a subject of debate. A wide range of masses have been reported in the literature ranging from as high as 8 M{sub Circled-Plus} to as low as 2.3 M{sub Circled-Plus }. This range in mass is largely due to the activity level of the star that contributes a significant amount of radial velocity (RV) 'jitter' and how the various methods correct this jitter. Although most mass determinations give a density consistent with a rocky planet, the lower value permits a bulk composition that can be up to 50% water. We present an analysis of the CoRoT-7b RV measurements that uses very few and simple assumptions in treating the activity signal. By analyzing those RV data for which multiple measurements were made in a given night, we remove the activity related RV contribution without any a priori model. We argue that the contribution of activity to the final RV curve is negligible and that the K-amplitude due to the planet is well constrained. This yields a mass of 7.42 {+-} 1.21 M{sub Circled-Plus} and a mean density of {rho} = 10.4 {+-} 1.8 gm cm{sup -3}. CoRoT-7b is similar in mass and radius to the second rocky planet to be discovered, Kepler-10b, and within the errors they have identical bulk densities-they are virtual twins. These bulk densities lie close to the density-radius relationship for terrestrial planets similar to what is seen for Mercury. CoRoT-7b and Kepler-10b may have an internal structure more like Mercury than the Earth.

  4. The Mass of CoRoT-7b

    Science.gov (United States)

    Hatzes, Artie P.; Fridlund, Malcolm; Nachmani, Gil; Mazeh, Tsevi; Valencia, Diana; Hébrard, Guillaume; Carone, Ludmila; Pätzold, Martin; Udry, Stephane; Bouchy, Francois; Deleuil, Magali; Moutou, Claire; Barge, Pierre; Bordé, Pascal; Deeg, Hans; Tingley, Brandon; Dvorak, Rudolf; Gandolfi, Davide; Ferraz-Mello, Sylvio; Wuchterl, Günther; Guenther, Eike; Guillot, Tristan; Rauer, Heike; Erikson, Anders; Cabrera, Juan; Csizmadia, Szilard; Léger, Alain; Lammer, Helmut; Weingrill, Jörg; Queloz, Didier; Alonso, Roi; Rouan, Daniel; Schneider, Jean

    2011-12-01

    The mass of CoRoT-7b, the first transiting super-Earth exoplanet, is still a subject of debate. A wide range of masses have been reported in the literature ranging from as high as 8 M ⊕ to as low as 2.3 M ⊕. This range in mass is largely due to the activity level of the star that contributes a significant amount of radial velocity (RV) "jitter" and how the various methods correct this jitter. Although most mass determinations give a density consistent with a rocky planet, the lower value permits a bulk composition that can be up to 50% water. We present an analysis of the CoRoT-7b RV measurements that uses very few and simple assumptions in treating the activity signal. By analyzing those RV data for which multiple measurements were made in a given night, we remove the activity related RV contribution without any a priori model. We argue that the contribution of activity to the final RV curve is negligible and that the K-amplitude due to the planet is well constrained. This yields a mass of 7.42 ± 1.21 M ⊕ and a mean density of ρ = 10.4 ± 1.8 gm cm-3. CoRoT-7b is similar in mass and radius to the second rocky planet to be discovered, Kepler-10b, and within the errors they have identical bulk densities—they are virtual twins. These bulk densities lie close to the density-radius relationship for terrestrial planets similar to what is seen for Mercury. CoRoT-7b and Kepler-10b may have an internal structure more like Mercury than the Earth.

  5. The HD(CP)2 Observational Prototype Experiment HOPE - Overview and Examples

    Science.gov (United States)

    Macke, Andreas

    2017-04-01

    The "HD(CP)2 Observational Prototype Experiment" (HOPE) was executed as a major 2-month field experiment in Jülich, Germany, performed in April and May 2013, followed by a smaller campaign in Melpitz, Germany in September 2013. HOPE has been designed to provide information on land-surface-atmospheric boundary layer exchange, aerosol, cloud and precipitation pattern for process studies and model evaluation with a focuses on the onset of clouds and precipitation in the convective atmospheric boundary layer. HOPE-Jülich instrumentation included a radio sounding station, 4 Doppler lidars, 4 Raman lidars,1 water vapour differential absorption lidar, 3 cloud radars, 5 microwave radiometers, 3 rain radars, 6 sky imagers, 99 pyranometers, and 4 Sun photometers operated in synergy at different supersites. The HOPE-Melpitz campaign combined ground-based remote sensing of aerosols and clouds with helicopter- and ballon-based in-situ observations in the atmospheric column and at the surface. HOPE provided an unprecedented collection of atmospheric dynamical, thermodynamical, and micro- and macrophysical properties of aerosols, clouds and precipitation with high spatial and temporal resolution within a cube of approximately 10 x 10 x 10 km3. HOPE data will significantly contribute to our understanding of boundary layer dynamics and the formation of clouds and precipitation. The datasets are made available through the Standardized Atmospheric Measurement Data SAMD archive at https://icdc.cen.uni-hamburg.de/index.php?id=samd. The presentation is based on an overview paper in ACP where results published in an ACP HOPE special issue are summarized, see http://www.atmos-chem-phys.net/special_issue366.html. Citation: Macke, A., Seifert, P., Baars, H., Beekmans, C., Behrendt, A., Bohn, B., Bühl, J., Crewell, S., Damian, T., Deneke, H., Düsing, S., Foth, A., Di Girolamo, P., Hammann, E., Heinze, R., Hirsikko, A., Kalisch, J., Kalthoff, N., Kinne, S., Kohler, M., Löhnert, U

  6. L1 retrotransposition in neurons is modulated by MeCP2.

    Science.gov (United States)

    Muotri, Alysson R; Marchetto, Maria C N; Coufal, Nicole G; Oefner, Ruth; Yeo, Gene; Nakashima, Kinichi; Gage, Fred H

    2010-11-18

    Long interspersed nuclear elements-1 (LINE-1 or L1s) are abundant retrotransposons that comprise approximately 20% of mammalian genomes. Active L1 retrotransposons can impact the genome in a variety of ways, creating insertions, deletions, new splice sites or gene expression fine-tuning. We have shown previously that L1 retrotransposons are capable of mobilization in neuronal progenitor cells from rodents and humans and evidence of massive L1 insertions was observed in adult brain tissues but not in other somatic tissues. In addition, L1 mobility in the adult hippocampus can be influenced by the environment. The neuronal specificity of somatic L1 retrotransposition in neural progenitors is partially due to the transition of a Sox2/HDAC1 repressor complex to a Wnt-mediated T-cell factor/lymphoid enhancer factor (TCF/LEF) transcriptional activator. The transcriptional switch accompanies chromatin remodelling during neuronal differentiation, allowing a transient stimulation of L1 transcription. The activity of L1 retrotransposons during brain development can have an impact on gene expression and neuronal function, thereby increasing brain-specific genetic mosaicism. Further understanding of the molecular mechanisms that regulate L1 expression should provide new insights into the role of L1 retrotransposition during brain development. Here we show that L1 neuronal transcription and retrotransposition in rodents are increased in the absence of methyl-CpG-binding protein 2 (MeCP2), a protein involved in global DNA methylation and human neurodevelopmental diseases. Using neuronal progenitor cells derived from human induced pluripotent stem cells and human tissues, we revealed that patients with Rett syndrome (RTT), carrying MeCP2 mutations, have increased susceptibility for L1 retrotransposition. Our data demonstrate that L1 retrotransposition can be controlled in a tissue-specific manner and that disease-related genetic mutations can influence the frequency of neuronal L

  7. Transit timing analysis of CoRoT-1b

    CERN Document Server

    Csizmadia, Sz; Barge, P; Agol, E; Aigrain, S; Alonso, R; Almenara, J M; Bonomo, A S; Borde, P; Bouchy, F; Cabrera, J; Deeg, H J; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Guenther, E W; Fridlund, M; Gondoin, P; Guillot, T; Hatzes, A; Jorda, L; Lammer, H; Lázaro, C; Leger, A; Llebaria, A; Magain, P; Moutou, C; Ollivier, M; Paetzold, M; Queloz, D; Rauer, H; Rouan, D; Schneider, J; Wuchterl, G; Gandolfi, D

    2009-01-01

    CoRoT, the pioneer space-based transit search, steadily provides thousands of high-precision light curves with continuous time sampling over periods of up to 5 months. The transits of a planet perturbed by an additional object are not strictly periodic. By studying the transit timing variations (TTVs), additional objects can be detected in the system. A transit timing analysis of CoRoT-1b is carried out to constrain the existence of additional planets in the system. We used data obtained by an improved version of the CoRoT data pipeline (version 2.0). Individual transits were fitted to determine the mid-transit times, and we analyzed the derived $O-C$ diagram. N-body integrations were used to place limits on secondary planets. No periodic timing variations with a period shorter than the observational window (55 days) are found. The presence of an Earth-mass Trojan is not likely. A planet of mass greater than $\\sim 1$ Earth mass can be ruled out by the present data if the object is in a 2:1 (exterior) mean mot...

  8. On the Mass of CoRoT-7b

    CERN Document Server

    Hatzes, Artie P; Nachmani, Gil; Mazeh, Tsevi; Valencia, Diana; Hebrard, Guillaume; Carone, Ludmila; Paetzold, Martin; Udry, Stephane; Bouchy, Francois; Borde, Pascal; Deeg, Hans; Tingley, Brandon; Dvorak, Rudolf; Gandolfi, Davide; Ferraz-Mello, Sylvio; Wuchterl, Guenther; Guenther, Eike; Rauer, Heike; Erikson, Anders; Cabrera, Juan; Csizmadia, Szilard; Leger, Alain; Lammer, Helmut; Weingrill, Joerg; Queloz, Didier; Alonso, Roi; Schneider, Jean

    2011-01-01

    The mass of CoRoT-7b, the first transiting superearth exoplanet, is still a subject of debate. A wide range of masses have been reported in the literature ranging from as high as 8 M_Earth to as low as 2.3 M_Earth. Although most mass determinations give a density consistent with a rocky planet, the lower value permits a bulk composition that can be up to 50% water. We present an analysis of the CoRoT-7b radial velocity measurements that uses very few and simple assumptions in treating the activity signal. By only analyzing those radial velocity data for which multiple measurements were made in a given night we remove the activity related radial velocity contribution without any a priori model. We demonstrate that the contribution of activity to the final radial velocity curve is negligible and that the K-amplitude due to the planet is well constrained. This yields a mass of 7.42 +/- 1.21 M_Earth and a mean density of rho = 10.4 +/- 1.8 gm cm^-3. CoRoT-7b is similar in mass and radius to the second rocky plane...

  9. Synthesis and Characterization of Ethylthioethylcyclopentadienyl Organolanthanide Complexes:Cp2Th LnCl (Ln=Gd, Dy), Cp2LnCpTh (Ln=Yb, Sm, Dy, Y) and Cp2ThErCl2·2THF

    Institute of Scientific and Technical Information of China (English)

    ZHU Ming朱铭; ZHANG Li-Bei张丽蓓; CHEN Ying-Hua陈应华; ZHOU Xi-Geng周锡庚; CAI Rui-Fang蔡瑞芳; WENG Lin-Hong翁林红

    2004-01-01

    Six new ethylthioethylcyclopentadienyl-containing organolanthanide complexes Cp2Th LnCl [Ln=Gd (1), Dy (2)]and Cp2LnCpTh [Cp=C5H5, Ln=Yb (3), Sm (4), Dy (5), Y (6)] were synthesized by the reaction of ethylthioethylcyclopentadienyl (CpTh) sodium salt with LnC13 or Cp2LnCl in THF. Complexes 1-6 were characterized by elemental analyses, infrared and mass spectroscopies. The molecular structures of complexes 1-3 were also determined by the X-ray single crystal diffraction. The results show that the side-chain sulfur atom on the ethylthioethylcyclopentadienyl ring can form intramolecular chelating coordination to the central lanthanide ion, improving the stability of organolanthanide complexes and reducing the number of coordinated THF molecules.

  10. Synthesis and Crystal Structure of [Cp2Ln(OC(SEt)NPh )]2

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-Mei; LIU Rui-Ting; ZHOU Xi-Geng

    2006-01-01

    Treatment of Cp3Y with EtSH, followed by reaction with an equivalent of PhNCO, yielded the dinuclear complex [Cp2Y(μ-η1:η3-OC(SEt)NPh )]2. The structure was characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction analysis. The title compound crysta- llizes in triclinic, space group P(1-) with a = 8.643(3), b = 10.752(4), c = 11.161(4)(A), α= 117.840(5), β= 94.086(5),γ= 101.008(5)°, V = 884.8(6)(A)3, Z = 1, Mr = 798.66 (C38H40N2O2S2Y2), λ(MoKα) = 0.710730(A),μ= 3.417 mm-1, Dc = 1.499 g/cm3, F(000) = 408, the final R = 0.0453 and wR = 0.1007 for 3067 unique reflections (Rint = 0.0317) with 2357 observed ones (I >2σ(I)). X-ray analysis reveals an unusual bonding mode of the OC(SEt)NPh ligand and the OCN fragment acts as a both bridging and side-on chelating ligand. Each yttrium atom is coordinated by two η5-cyclopentadienyl groups, one chelating η3-OC(SEt)NPh ligand and one bridging O atom from another η3-OC(SEt)NPh ligand.

  11. Cp2TiCl/D2O/Mn, a formidable reagent for the deuteration of organic compounds

    Science.gov (United States)

    Rodríguez-García, Ignacio

    2016-01-01

    Summary Cp2TiCl/D2O/Mn is an efficient combination, sustainable and cheap reagent that mediates the D-atom transfer from D2O to different functional groups and can contribute to the synthesis of new deuterated organic compounds under friendly experimental conditions and with great economic advantages. PMID:27559410

  12. Disease modeling using embryonic stem cells: MeCP2 regulates nuclear size and RNA synthesis in neurons

    NARCIS (Netherlands)

    S. Yazdani (Saami); R. Deogracias (Rubén); J.A. Guy (Jacqueline); R.A. Poot (Raymond); A. Bird (Adrian); Y.A. Barde

    2012-01-01

    textabstractMutations in the gene encoding the methyl-CpG-binding protein MECP2 are the major cause of Rett syndrome, an autism spectrum disorder mainly affecting young females. MeCP2 is an abundant chromatin-associated protein, but how and when its absence begins to alter brain function is still fa

  13. Cp2TiCl/D2O/Mn, a formidable reagent for the deuteration of organic compounds

    Directory of Open Access Journals (Sweden)

    Antonio Rosales

    2016-07-01

    Full Text Available Cp2TiCl/D2O/Mn is an efficient combination, sustainable and cheap reagent that mediates the D-atom transfer from D2O to different functional groups and can contribute to the synthesis of new deuterated organic compounds under friendly experimental conditions and with great economic advantages.

  14. Disease modeling using embryonic stem cells: MeCP2 regulates nuclear size and RNA synthesis in neurons

    NARCIS (Netherlands)

    S. Yazdani (Saami); R. Deogracias (Rubén); J.A. Guy (Jacqueline); R.A. Poot (Raymond); A. Bird (Adrian); Y.A. Barde

    2012-01-01

    textabstractMutations in the gene encoding the methyl-CpG-binding protein MECP2 are the major cause of Rett syndrome, an autism spectrum disorder mainly affecting young females. MeCP2 is an abundant chromatin-associated protein, but how and when its absence begins to alter brain function is still

  15. 桃拉综合征病毒CP2蛋白的克隆表达及其结合肽的噬菌体肽库筛选%Cloning, expression of the CP2 gene of Taura syndrome virus and screen ligands from phage display random dodecapeptide library for CP2 protein

    Institute of Scientific and Technical Information of China (English)

    黄新新; 陆承平; 孔繁德; 蔡强

    2013-01-01

    目的:克隆表达出桃拉综合征病毒(TSV)主要衣壳蛋白CP2蛋白,并通过对噬菌体随机肽库的淘选,得到与CP2蛋白结合的相关多肽,以探讨CP2蛋白与配体作用的特异位点.方法:根据重组质粒pMD-CP2的核苷酸序列,设计并合成了一对引物,扩增TSV CP2基因高变区376~1 371 bp,扩增片段插入pET-32构建成原核表达载体pET-CP2.该重组载体在IPTG诱导下进行可溶性表达,SDS-PAGE电泳检测表达的CP2蛋白.以纯化的CP2蛋白作为筛选分子,对噬菌体展示12肽库进行亲和淘选.结果:原核表达出56 kD大小的CP2蛋白,对噬菌体12肽库4轮"吸附-洗脱-扩增"淘洗后,所得的噬菌体回收率逐步提高,由6.4×10-5上升到2.8×10-2,显示淘选过程对随机肽库有很好的富集效果.随机挑选第4轮淘筛后的36个单克隆噬菌体,ELISA鉴定有24个单克隆(66.6%)为强阳性.将这24个阳性克隆扩增、测序,推导随机多肽的氨基酸序列.分析发现,有7个克隆(克隆号2、6、7、9、18、20、33)完全一致,序列为HTSFCSTHLCLI,其它的几个克隆如克隆3及28序列为HCSNLFCSLDLP;克隆5为HCSHTLCALHVM;克隆26为HCNSWLCPLITD也与该7个克隆有相似的序列,经比对核心序列为HCS及LCL.结论:首次用重组的TSV CP2蛋白从噬菌体随机12肽库中筛选到特异结合的肽序列,其共有结构特征为明确CP2与结合蛋白的相互作用位点提供支持.

  16. A search for circumbinary planets in CoRoT eclipsing binary light curves

    Directory of Open Access Journals (Sweden)

    Klagyivik Peter

    2015-01-01

    Full Text Available Several transiting circumbinary planets have been found in data of the Kepler mission [1–5]. Both CoRoT and Kepler have surveyed similar numbers of stars, and the photometric precision of CoRoT is sufficient that it could detect most of the known circumbinary planets; the main draw-back by CoRoT is the much shorter coverage. Still, there is a high chance that some circumbinary planets may be found in its sample of eclipsing binaries (hereafter EBs. Here we report on an ongoing search for circumbinary planets in the full CoRoT data set.

  17. Generation and characterization of rat and mouse monoclonal antibodies specific for MeCP2 and their use in X-inactivation studies.

    Directory of Open Access Journals (Sweden)

    K Laurence Jost

    Full Text Available Methyl CpG binding protein 2 (MeCP2 binds DNA, and has a preference for methylated CpGs and, hence, in cells, it accumulates in heterochromatin. Even though it is expressed ubiquitously MeCP2 is particularly important during neuronal maturation. This is underscored by the fact that in Rett syndrome, a neurological disease, 80% of patients carry a mutation in the MECP2 gene. Since the MECP2 gene lies on the X chromosome and is subjected to X chromosome inactivation, affected patients are usually chimeric for wild type and mutant MeCP2. Here, we present the generation and characterization of the first rat monoclonal MeCP2 specific antibodies as well as mouse monoclonal antibodies and a rabbit polyclonal antibody. We demonstrate that our antibodies are suitable for immunoblotting, (chromatin immunoprecipitation and immunofluorescence of endogenous and ectopically expressed MeCP2. Epitope mapping revealed that most of the MeCP2 monoclonal antibodies recognize the C-terminal domain and one the N-terminal domain of MeCP2. Using slot blot analysis, we determined a high sensitivity of all antibodies, detecting amounts as low as 1 ng of MeCP2 protein. Moreover, the antibodies recognize MeCP2 from different species, including human, mouse, rat and pig. Lastly, we have validated their use by analyzing and quantifying X chromosome inactivation skewing using brain tissue of MeCP2 heterozygous null female mice. The new MeCP2 specific monoclonal antibodies described here perform well in a large variety of immunological applications making them a very valuable set of tools for studies of MeCP2 pathophysiology in situ and in vitro.

  18. The large momentum transfer reaction 12C(p,2p+n) as a new method for measuring short range NN correlations in nuclei

    Science.gov (United States)

    Aclander, J.; Alster, J.; Barton, D.; Bunce, G.; Carroll, A.; Christensen, N.; Courant, H.; Durrant, S.; Gushue, S.; Heppelmann, S.; Kosonovsky, E.; Mardor, I.; Mardor, Y.; Marshak, M.; Makdisi, Y.; Minor, E. D.; Navon, I.; Nicholson, H.; Piasetzky, E.; Roser, T.; Russell, J.; Sargsian, M.; Sutton, C. S.; Tanaka, M.; White, C.; Wu, J.-Y.

    1999-05-01

    The reaction 12C(p,2p+n) was measured for momentum transfers of 4.8 and 6.2 (GeV/c)2 at beam momenta of 5.9 and 7.5 GeV/c. We measured the quasi-elastic reaction(p,2p) atθcm~=90 deg, in a kinematically complete measurement. The neutron momentum was measured in triple coincidence with the two emerging high momentum protons. We present the correlation between the momenta of the struck target proton and the neutron. The events are associated with the high momentum components of the nuclear wave function. We present sparse data which, combined with a quasi elastic description of the (p,2p) reaction and kinematical arguments, point to a novel way for isolating two-nucleon short range correlations.

  19. Warm Spitzer Photometry of the Transiting Exoplanets CoRoT-1 and CoRoT-2 at Secondary Eclipse

    CERN Document Server

    Deming, Drake; Agol, Eric; Desert, Jean-Michel; Burrows, Adam; Fortney, Jonathan J; Charbonneau, David; Cowan, Nicolas B; Laughlin, Gregory; Langton, Jonathan; Showman, Adam P; Lewis, Nikole K

    2010-01-01

    We measure secondary eclipses of the hot giant exoplanets CoRoT-1 at 3.6 and 4.5 microns, and CoRoT-2 at 3.6 microns, both using Warm Spitzer. We find that the Warm Spitzer mission is working very well for exoplanet science. For consistency of our analysis we also re-analyze archival cryogenic Spitzer data for secondary eclipses of CoRoT-2 at 4.5 and 8 microns. We compare the total data for both planets, including optical eclipse measurements by the CoRoT mission, and ground-based eclipse measurements at 2 microns, to existing models. Both planets exhibit stronger eclipses at 4.5 than at 3.6 microns, which is often indicative of an atmospheric temperature inversion. The spectrum of CoRoT-1 is best reproduced by a 2460K blackbody, due either to a high altitude layer that strongly absorbs stellar irradiance, or an isothermal region in the planetary atmosphere. The spectrum of CoRoT-2 is unusual because the 8 micron contrast is anomalously low. Non-inverted atmospheres could potentially produce the CoRoT-2 spect...

  20. PIAS1 regulates CP2c localization and active promoter complex formation in erythroid cell-specific α-globin expression

    OpenAIRE

    Chul Kang, Ho; Hyung Chae, Ji; Jeon, Jinseon; Kim, Won; Hyun Ha, Dae; Ho Shin, June; Gil Kim, Chan; Geun Kim, Chul

    2010-01-01

    Data presented here extends our previous observations on α-globin transcriptional regulation by the CP2 and PIAS1 proteins. Using RNAi knockdown, we have now shown that CP2b, CP2c and PIAS1 are each necessary for synergistic activation of endogenous α-globin gene expression in differentiating MEL cells. In this system, truncated PIAS1 mutants lacking the ring finger domain recruited CP2c to the nucleus, as did wild-type PIAS1, demonstrating that this is a sumoylation-independent process. In v...

  1. Corotational Tomography of Heliospheric Features Using Global Thomson Scattering Data

    Science.gov (United States)

    Jackson, Bernard V.; Hick, P. Paul

    2002-12-01

    The Air Force/NASA Solar Mass Ejection Imager (SMEI) will provide two-dimensional images of the sky in visible light with high (0.1%) photometric precision, and unprecedented sky coverage and cadence. To optimize the information available from these images they must be interpreted in three dimensions. We have developed a Computer Assisted Tomography (CAT) technique that fits a three-dimensional kinematic heliospheric model to remotely-sensed Thomson scattering observations. This technique is designed specifically to determine the corotating background solar wind component from data provided by instruments like SMEI. Here, we present results from this technique applied to the Helios spacecraft photometer observations. The tomography program iterates to a least-squares solution of observed brightnesses using solar rotation, spacecraft motion and solar wind outflow to provide perspective views of each point in space covered by the observations. The corotational tomography described here is essentially the same as used by Jackson et al. (1998) for the analysis of interplanetary scintillation (IPS) observations. While IPS observations are related indirectly to the solar wind density through an assumed (and uncertain) relationship between small-scale density fluctuations and density, Thomson scattering physics is more straightforward, i.e., the observed brightness depends linearly on the solar wind density everywhere in the heliosphere. Consequently, Thomson scattering tomography can use a more direct density-convergence criterion to match observed Helios photometer brightness to brightness calculated from the model density. The general similarities between results based on IPS and Thomson scattering tomography validate both techniques and confirm that both observe the same type of solar wind structures. We show results for Carrington rotation 1653 near solar minimum. We find that longitudinally segmented dense structures corotate with the Sun and emanate from near the

  2. The Space Stellar Photometry Mission COROT: Asteroseismology and Search for Extrasolar Planets

    Indian Academy of Sciences (India)

    Annie Baglin; Gerard Vauclair; Corot team

    2000-09-01

    The main scientific objectives, asteroseismology and search for extrasolar planets for the COROT photometric mission are presented, and its interest in terms of stellar variability. A description of the payload, details of the scientific program, the ground based preparatory observations and bibliography can be found at http://www.astrsp-mrs.fr/corot/pagecorot.html.

  3. Planetary transit candidates in CoRoT LRa01 field

    DEFF Research Database (Denmark)

    Carone, L.; Gandolfi, D.; Cabrera, J.;

    2012-01-01

    We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. We acquired and analyzed 7470 chromatic and 3938 monochromatic...

  4. SYNTHESIS OF CATIONIC CERIUM COMPOUNDS [CP2CE(L)2][BPH4] (L = TETRAHYDROFURAN OR TETRAHYDROTHIOPHENE) AND THE CRYSTAL-STRUCTURE OF THE TETRAHYDROTHIOPHENE DERIVATIVE

    NARCIS (Netherlands)

    HEERES, HJ; MEETSMA, A; TEUBEN, JH

    1991-01-01

    Protolysis of the cerium alkyl Cp2*CeCH(SiMe3)2 (1) by triethylammoniumtetraphenylborate provides a useful route to cationic cerium compounds [Cp2*Ce(L)2][BPh4] (2, L = tetrahydrofuran; 3, L = tetrahydrothiophene). The crystal structure of the tetrahydrothiophene derivative was determined by X-ray d

  5. Synthesis and Magnetic Properties of the Intercalation Compound FePS3 (CoCp2)0.40

    Institute of Scientific and Technical Information of China (English)

    LIN Jun; DAI Yao-Dong; HE Yun; HUANG Hong-Bo; XIAO Fan; XIA Yuan-Fu

    2004-01-01

    @@ Intercalation compound FePS3 (CoCp2 )0.40 (CoCp2 = cobaltocene) was synthesized, and the crystal structure and magnetic properties were studied by x-ray diffraction, magnetic susceptibility measurement, and Mossbauer spectroscopy. The crystal structure was indexed to monoclinic unit cell with a = 5.996A, b = 10.106A, c =12.511 A, β = 105.916°, and about 5.6 A expansion at the c-direction compared to pure FePS3. The Mossbauer spectra indicate that there are three kinds of divalent ions with high spin state in the intercalation compound,which implies charge transfer from guest to the Fe-S e*g anti-bonding orbits of the host lattice. No cationic vacancies are formed in the intercalation compound. The ferromagnetism at low temperature originates from the spin canting of divalent ions.

  6. The CoRoT Mission - Status and Preliminary Results

    Science.gov (United States)

    Fridlund, M.

    2007-08-01

    The CoRoT (Convection, Rotation and planetary Transits) space mission is the first dedicated space mission designed to search for exo-planets akin to our own. It is a joint effort by France, Austria Belgium, Brazil, Germany, Spain and the European Space Agency. It is specifically designed to search for exo-planets much smaller than hitherto discovered. It was launched in December 2006 on a mission lasting not less than 3 years. Verification and first operations have proven the mission to superceed all expectations. This is of course most relevant in the fact that planets as small as our own Earth are detectable. In this presentation we describe the experiences of the first 6 mo0nths of the mission, the actual status of the mission, the supporting ground based program, and what we expect in the near future. After giving examples of data relevant to the topic of this session, we turn to describing the expected impact of the results of CoRoT on future endeavours such as KEPLER, Extremely Large Telescopes (ELT's) and ultimately Darwin.

  7. Theoretical planetary mass spectra - a predition for COROT

    CERN Document Server

    Broeg, C

    2008-01-01

    The satellite COROT will search for close-in exo-planets around a few thousand stars using the transit search method. The COROT mission holds the promise of detecting numerous exo-planets. Together with radial velocity follow-up observations, the masses of the detected planets will be known. We have devised a method for predicting the expected planetary populations and compared it to the already known exo-planets. Our method works by looking at all hydrostatic envelope solutions of giant gas planets that could possibly exist in arbitrary planetary nebulae and comparing the relative abundance of different masses. We have completed the first such survey of hydrostatic equilibria in an orbital range covering periods of 1 to 50 days. Statistical analysis of the calculated envelopes suggests division into three classes of giant planets that are distinguished by orbital separation. We term them classes G (close-in), H, and J (large separation). Each class has distinct properties such as a typical mass range. Furthe...

  8. CoRoT space photometry of seven Cepheids

    CERN Document Server

    Poretti, Ennio; Rainer, Monica; Baglin, Annie; Benko, Jozsef; Debosscher, Jonas; Weiss, Werner W

    2015-01-01

    A few Galactic classical Cepheids were observed in the programmes of space missions as Coriolis, MOST and Kepler. An appealing opportunity was to detect additional nonradial modes, thus opening the possibility to perform asteroseismic studies and making the pulsational content of Galactic Cepheids more similar to that of Magellanic Clouds ones. However, only hints of cycle-to-cycle variations were found, without any strict periodicity. In this context the potential of the CoRoT exoplanetary data base was not fully exploited despite the wide area covered on the Galactic plane. Therefore, we investigated all the candidate Cepheids pointed out by the automatic classification of the CoRoT curves. At the end we could identify seven bona-fide Cepheids. The light curves were investigated to remove some instrumental effects. The frequency analysis was particularly delicate since these small effects can be enhanced by the large amplitude, resulting in the presence of significant, but spurious, peaks in the power spect...

  9. Improved stellar parameters of CoRoT-7

    CERN Document Server

    Bruntt, H; Fridlund, M; Alonso, R; Bouchy, F; Hatzes, A; Mayor, M; Moutou, C; Queloz, D

    2010-01-01

    Accurate parameters of the host stars of exoplanets are important for the interpretation of the new planet systems that continue to emerge. The CoRoT satellite recently discovered a transiting rocky planet with a density similar to the inner planets in our solar system, a so-called Super Earth. This planet is orbiting a relatively faint G9V star called CoRoT-7, and we wish to refine its physical properties, which are important for the interpretation of the properties of the planet system. We used spectra from HARPS@ESO-3.6m and UVES@VLT-8.2m. From the analysis of Fe-1 and Fe-2 lines we determine Teff, log g and microturbulence. We use the Balmer lines to constrain Teff and pressure sensitive Mg-1b and Ca lines to constrain log g. From the analysis we find Teff=5250+-60K, log g = 4.47+-0.05, [M/H]=+0.12+-0.06, and vsini = 1.1 km/s. We compared the L/M ratio with isochrones to constrain the evolutionary status. Using the age estimate of 1.2-2.3 Gyr based on stellar activity, we determine the mass and radius 0.9...

  10. The secondary eclipse of CoRoT-1b

    CERN Document Server

    Alonso, R; Aigrain, S; Auvergne, M; Baglin, A; Barbieri, M; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Chaintreuil, S; De la Reza, R; Deeg, H J; Deleuil, M; Dvorak, R; Erikson, A; Fridlund, M; Fialho, F; Gondoin, P; Guillot, T; Hatzes, A; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Patzold, M; Pont, F; Queloz, D; Rauer, H; Rouan, D; Schneider, J; Wuchterl, G

    2009-01-01

    The transiting planet CoRoT-1b is thought to belong to the pM-class of planets, in which the thermal emission dominates in the optical wavelengths. We present a detection of its secondary eclipse in the CoRoT white channel data, whose response function goes from ~400 to ~1000 nm. We used two different filtering approaches, and several methods to evaluate the significance of a detection of the secondary eclipse. We detect a secondary eclipse centered within 20 min at the expected times for a circular orbit, with a depth of 0.016+/-0.006%. The center of the eclipse is translated in a 1-sigma upper limit to the planet's eccentricity of ecosomega<0.014. Under the assumption of a zero Bond Albedo and blackbody emission from the planet, it corresponds to a T_{CoRoT}=2330 +120-140 K. We provide the equilibrium temperatures of the planet as a function of the amount of reflected light. If the planet is in thermal equilibrium with the incident flux from the star, our results imply an inefficient transport mechanism ...

  11. 2008款雅阁CP2车VSA和ABS故障灯异常点亮

    Institute of Scientific and Technical Information of China (English)

    徐界东

    2012-01-01

    故障现象一辆2008款雅阁CP2轿车,行驶里程约为5 000 km,在正常行驶过程中汽车辅助稳定(VSA)系统和ABS故障灯异常点亮。故障诊断接通点火开关,发现仪表盘上VSA和ABS故障灯常亮。

  12. Linking Epigenetics to Human Disease and Rett Syndrome: The Emerging Novel and Challenging Concepts in MeCP2 Research

    OpenAIRE

    Robby Mathew Zachariah; Mojgan Rastegar

    2012-01-01

    Epigenetics refer to inheritable changes beyond DNA sequence that control cell identity and morphology. Epigenetics play key roles in development and cell fate commitments and highly impact the etiology of many human diseases. A well-known link between epigenetics and human disease is the X-linked MECP2 gene, mutations in which lead to the neurological disorder, Rett Syndrome. Despite the fact that MeCP2 was discovered about 20 years ago, our current knowledge about its molecular function is ...

  13. Characterization of the genomic structure, chromosomal location, promoter, and development expression of the alpha-globin transcription factor CP2.

    Science.gov (United States)

    Swendeman, S L; Spielholz, C; Jenkins, N A; Gilbert, D J; Copeland, N G; Sheffery, M

    1994-04-15

    We recently cloned murine and human cDNAs that encode CP2, a cellular transcription factor that interacts with the alpha-globin promoter as well as with additional cellular and viral promoter elements. We have now characterized the genomic structure, chromosome location, promoter, and expression pattern of the factor. Genes for the murine and human mRNAs contained 16 and 15 exons, respectively. Both genes spanned approximately 30 kilobases of chromosomal DNA, and among coding exons, all exon/intron boundaries were conserved. The human gene for CP2 was found to reside on chromosome 12 while the murine gene mapped to the distal end of chromosome 15, near Gdc-1, Wnt-1, and Rarg, a region syntenic with human chromosome 12. The murine and human promoters initiated mRNAs at multiple start sites in a conserved region that spanned more than 450 nucleotides. Lastly, a study of the pattern of CP2 gene expression showed that the factor was expressed in all adult and fetal murine tissues examined from at least day 9.5 of development.

  14. Uroporphyrinogen III synthase erythroid promoter mutations in adjacent GATA1 and CP2 elements cause congenital erythropoietic porphyria.

    Science.gov (United States)

    Solis, C; Aizencang, G I; Astrin, K H; Bishop, D F; Desnick, R J

    2001-03-01

    Congenital erythropoietic porphyria, an autosomal recessive inborn error of heme biosynthesis, results from the markedly deficient activity of uroporphyrinogen III synthase. Extensive mutation analyses of 40 unrelated patients only identified approximately 90% of mutant alleles. Sequencing the recently discovered erythroid-specific promoter in six patients with a single undefined allele identified four novel mutations clustered in a 20-bp region: (a) a -70T to C transition in a putative GATA-1 consensus binding element, (b) a -76G to A transition, (c) a -86C to A transversion in three unrelated patients, and (d) a -90C to A transversion in a putative CP2 binding motif. Also, a -224T to C polymorphism was present in approximately 4% of 200 unrelated Caucasian alleles. We inserted these mutant sequences into luciferase reporter constructs. When transfected into K562 erythroid cells, these constructs yielded 3 +/- 1, 54 +/- 3, 43 +/- 6, and 8 +/- 1%, respectively, of the reporter activity conferred by the wild-type promoter. Electrophoretic mobility shift assays indicated that the -70C mutation altered GATA1 binding, whereas the adjacent -76A mutation did not. Similarly, the -90C mutation altered CP2 binding, whereas the -86A mutation did not. Thus, these four pathogenic erythroid promoter mutations impaired erythroid-specific transcription, caused CEP, and identified functionally important GATA1 and CP2 transcriptional binding elements for erythroid-specific heme biosynthesis.

  15. F Ring Core Stability: Corotation Resonance Plus Antiresonance

    Science.gov (United States)

    Cuzzi, Jeffrey N.; Marouf, Essam; French, Richard; Jacobson, Robert

    2014-01-01

    The decades-or-longer stability of the narrow F Ring core in a sea of orbital chaos appears to be due to an unusual combination of traditional corotation resonance and a novel kind of "antiresonance". At a series of specific locations in the F Ring region, apse precession between synodic encounters with Prometheus allows semimajor axis perturbations to promptly cancel before significant orbital period changes can occur. This cancellation fails for particles that encounter Prometheus when it is near its apoapse, especially during periods of antialignment of its apse with that of the F Ring. At these times, the strength of the semimajor axis perturbation is large (tens of km) and highly nonsinusoidal in encounter longitude, making it impossible to cancel promptly on a subsequent encounter and leading to chaotic orbital diffusion. Only particles that consistently encounter Prometheus away from its apoapse can use antiresonance to maintain stable orbits, implying that the true mean motion nF of the stable core must be defined by a corotational resonance of the form nF = nP(-kappa)P/m, where (nP, kappaP) are Prometheus' mean motion and epicycle frequency. To test this hypothesis we used the fact that Cassini RSS occultations only sporadically detect a "massive" F Ring core, composed of several-cm-and-larger particles. We regressed the inertial longitudes of 24 Cassini RSS (and VGR) detections and 43 nondetections to a common epoch, using a comb of candidate nP, and then folded them modulo the anticipated m-number of the corotational resonance (Prometheus m = 110 outer CER), to see if clustering appears. We find the "true F Ring core" is actually arranged in a series of short longitudinal arcs separated by nearly empty longitudes, orbiting at a well determined semimajor axis of 140222.4 km (from 2005-2012 at least). Small particles seen by imaging and stellar occultations spread quickly in azimuth and obscure this clumpy structure. Small chaotic variations in the mean

  16. MeCP2 binds to nucleosome free (linker DNA) regions and to H3K9/H3K27 methylated nucleosomes in the brain

    Science.gov (United States)

    Thambirajah, Anita A.; Ng, Marlee K.; Frehlick, Lindsay J.; Li, Andra; Serpa, Jason J.; Petrotchenko, Evgeniy V.; Silva-Moreno, Begonia; Missiaen, Kristal K.; Borchers, Christoph H.; Adam Hall, J.; Mackie, Ryan; Lutz, Frank; Gowen, Brent E.; Hendzel, Michael; Georgel, Philippe T.; Ausió, Juan

    2012-01-01

    Methyl-CpG-binding protein 2 (MeCP2) is a chromatin-binding protein that mediates transcriptional regulation, and is highly abundant in brain. The nature of its binding to reconstituted templates has been well characterized in vitro. However, its interactions with native chromatin are less understood. Here we show that MeCP2 displays a distinct distribution within fractionated chromatin from various tissues and cell types. Artificially induced global changes in DNA methylation by 3-aminobenzamide or 5-aza-2′-deoxycytidine, do not significantly affect the distribution or amount of MeCP2 in HeLa S3 or 3T3 cells. Most MeCP2 in brain is chromatin-bound and localized within highly nuclease-accessible regions. We also show that, while in most tissues and cell lines, MeCP2 forms stable complexes with nucleosome, in brain, a fraction of it is loosely bound to chromatin, likely to nucleosome-depleted regions. Finally, we provide evidence for novel associations of MeCP2 with mononucleosomes containing histone H2A.X, H3K9me2 and H3K27me3 in different chromatin fractions from brain cortex and in vitro. We postulate that the functional compartmentalization and tissue-specific distribution of MeCP2 within different chromatin types may be directed by its association with nucleosomes containing specific histone variants, and post-translational modifications. PMID:22144686

  17. Novel function of the poly(c)-binding protein α-CP2 as a transcriptional activator that binds to single-stranded DNA sequences.

    Science.gov (United States)

    Kang, Duk-Hee; Song, Kyu Young; Wei, Li-Na; Law, Ping-Yee; Loh, Horace H; Choi, Hack Sun

    2013-11-01

    α-complex protein 2 (α-CP2) is known as an RNA-binding protein that interacts in a sequence-specific manner with single-stranded polycytosine [poly(C)]. This protein is involved in various post-transcriptional regulations, such as mRNA stabilization and translational regulation. In this study, the full-length mouse α-CP2 gene was expressed in an insoluble form with an N-terminal histidine tag in Escherichia coli and purified for homogeneity using affinity column chromatography. Its identity was confirmed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Recombinant α-CP2 was expressed and refolded. The protein folding conditions for denatured α-CP2 were optimized. DNA and RNA electrophoretic mobility shift assays demonstrated that the recombinant α-CP2 is capable of binding to both single-stranded DNA and RNA poly(C) sequences. Furthermore, plasmids expressing α-CP2 activated the expression of a luciferase reporter when co-transfected with a single-stranded (pGL-SS) construct containing a poly(C) sequence. To our knowledge, this study demonstrates for the first time that α-CP2 functions as a transcriptional activator by binding to a single-stranded poly(C) sequence.

  18. The power of low-resolution spectroscopy: On the spectral classification of planet candidates in the ground-based CoRoT follow-up

    CERN Document Server

    Eiff, M Ammler-von; Guenther, E W; Stecklum, B; Cabrera, J

    2015-01-01

    Planetary transits detected by the CoRoT mission can be mimicked by a low-mass star in orbit around a giant star. Spectral classification helps to identify the giant stars and also early-type stars which are often excluded from further follow-up. We study the potential and the limitations of low-resolution spectroscopy to improve the photometric spectral types of CoRoT candidates. In particular, we want to study the influence of the signal-to-noise ratio (SNR) of the target spectrum in a quantitative way. We built an own template library and investigate whether a template library from the literature is able to reproduce the classifications. Including previous photometric estimates, we show how the additional spectroscopic information improves the constraints on spectral type. Low-resolution spectroscopy ($R\\approx$1000) of 42 CoRoT targets covering a wide range in SNR (1-437) and of 149 templates was obtained in 2012-2013 with the Nasmyth spectrograph at the Tautenburg 2m telescope. Spectral types have been d...

  19. The CP2 domain of leucyl-tRNA synthetase is crucial for amino acid activation and post-transfer editing.

    Science.gov (United States)

    Zhou, Xiao-Long; Zhu, Bin; Wang, En-Duo

    2008-12-26

    Leucyl-tRNA synthetase (LeuRS) has an insertion domain, called connective peptide 2 (CP2), either directly preceding or following the editing domain (CP1 domain), depending on the species. The global structures of the CP2 domains from all LeuRSs are similar. Although the CP1 domain has been extensively explored to be responsible for hydrolysis of mischarged tRNALeu, the role of the CP2 domain remains undefined. In the present work, deletion of the CP2 domain of Giardia lamblia LeuRS (GlLeuRS) showed that the CP2 domain is indispensable for amino acid activation and post-transfer editing and that it contributes to LeuRS-tRNALeu binding affinity. In addition, its functions are conserved in both eukaryotic/archaeal and prokaryotic LeuRSs from G. lamblia, Pyrococcus horikoshii (PhLeuRS), and Escherichia coli (EcLeuRS). Alanine scanning and site-directed mutagenesis assays of the CP2 domain identified several residues that are crucial for its various functions. Data from the chimeric mutants, which replaced the CP2 domain of GlLeuRS with either PhLeuRS or EcLeuRS, showed that the CP2 domain of PhLeuRS but not that of EcLeuRS can partially restore amino acid activation and post-transfer editing functions, suggesting that the functions of the CP2 domain are dependent on its location in the primary sequence of LeuRS.

  20. Co-localization of the oncogenic transcription factor MYCN and the DNA methyl binding protein MeCP2 at genomic sites in neuroblastoma.

    Directory of Open Access Journals (Sweden)

    Derek M Murphy

    Full Text Available BACKGROUND: MYCN is a transcription factor that is expressed during the development of the neural crest and its dysregulation plays a major role in the pathogenesis of pediatric cancers such as neuroblastoma, medulloblastoma and rhabdomyosarcoma. MeCP2 is a CpG methyl binding protein which has been associated with a number of cancers and developmental disorders, particularly Rett syndrome. METHODS AND FINDINGS: Using an integrative global genomics approach involving chromatin immunoprecipitation applied to microarrays, we have determined that MYCN and MeCP2 co-localize to gene promoter regions, as well as inter/intragenic sites, within the neuroblastoma genome (MYCN amplified Kelly cells at high frequency (70.2% of MYCN sites were also positive for MeCP2. Intriguingly, the frequency of co-localization was significantly less at promoter regions exhibiting substantial hypermethylation (8.7%, as determined by methylated DNA immunoprecipitation (MeDIP applied to the same microarrays. Co-immunoprecipitation of MYCN using an anti-MeCP2 antibody indicated that a MYCN/MeCP2 interaction occurs at protein level. mRNA expression profiling revealed that the median expression of genes with promoters bound by MYCN was significantly higher than for genes bound by MeCP2, and that genes bound by both proteins had intermediate expression. Pathway analysis was carried out for genes bound by MYCN, MeCP2 or MYCN/MeCP2, revealing higher order functions. CONCLUSIONS: Our results indicate that MYCN and MeCP2 protein interact and co-localize to similar genomic sites at very high frequency, and that the patterns of binding of these proteins can be associated with significant differences in transcriptional activity. Although it is not yet known if this interaction contributes to neuroblastoma disease pathogenesis, it is intriguing that the interaction occurs at the promoter regions of several genes important for the development of neuroblastoma, including ALK, AURKA and

  1. Transgenic tomato plants expressing the antigen gene PfCP-2.9 of Plasmodium falciparum Plantas transgênicas de tomate expressando o gene do antígeno PfCP-2.9 de Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Mihail Kantor

    2013-01-01

    Full Text Available The objective of this work was to obtain transgenic tomato plants expressing the PfCP-2.9 protein (a chimera of the antigens MSP1 and AMA1 of Plasmodium falciparum. Cotyledons of seven-day-old tomatoes, cultivar Summers, were transformed via Agrobacterium tumefaciens. Transgenic expression in the T0 plants was verified in the DNA extracted from fruits. PCR analysis was used to test the presence of the gene of interest in the T1 generation. Reverse transcriptase PCR provided evidence of gene expression at the RNA level, and Western blot analysis confirmed the presence of the protein of interest in the T1 plants. This is the first report of successful transformation with the expression of a malaria antigen (PfCP-2.9 in transgenic tomato plants from the T0 and T1 generations.O objetivo deste trabalho foi obter plantas transgênicas de tomate que expressem a proteína PfCP-2.9 (uma quimera dos antígenos MSP1 e AMA1 de Plasmodium falciparum. Cotilédones de tomate, cultivar Summers, com sete dias de idade, foram transformados via Agrobacterium tumefaciens. A expressão transgênica nas plantas T0 foi verificada no DNA extraído dos frutos. A análise por PCR foi utilizada para testar a presença do gene de interesse na geração T1. A evidência da expressão do gene no RNA foi constatada por meio da PCR de transcriptase reversa, e a análise "Western blot" confirmou a presença da proteína de interesse nas plantas T1. Este é o primeiro relato de transformação bem sucedida com a expressão de um antígeno da malária (PfCP-2,9 em plantas transgênicas de tomate da geração T0 e T1.

  2. Dynamical corotation torques on low-mass planets

    CERN Document Server

    Paardekooper, Sijme-Jan

    2014-01-01

    We study torques on migrating low-mass planets in locally isothermal discs. Previous work on low-mass planets generally kept the planet on a fixed orbit, after which the torque on the planet was measured. In addition to these static torques, when the planet is allowed to migrate it experiences dynamical torques, which are proportional to the migration rate and whose sign depends on the background vortensity gradient. We show that in discs a few times more massive than the Minimum Mass Solar Nebula, these dynamical torques can have a profound impact on planet migration. Inward migration can be slowed down significantly, and if static torques lead to outward migration, dynamical torques can take over, taking the planet beyond zero-torque lines set by saturation of the corotation torque in a runaway fashion. This means the region in non-isothermal discs where outward migration is possible can be larger than what would be concluded from static torques alone.

  3. GAUDI: A Preparatory Archive for the COROT Mission

    Science.gov (United States)

    Solano, E.; Catala, C.; Garrido, R.; Poretti, E.; Janot-Pacheco, E.; Gutiérrez, R.; González, R.; Mantegazza, L.; Neiner, C.; Fremat, Y.; Charpinet, S.; Weiss, W.; Amado, P. J.; Rainer, M.; Tsymbal, V.; Lyashko, D.; Ballereau, D.; Bouret, J. C.; Hua, T.; Katz, D.; Lignières, F.; Lüftinger, T.; Mittermayer, P.; Nesvacil, N.; Soubiran, C.; van't Veer-Menneret, C.; Goupil, M. J.; Costa, V.; Rolland, A.; Antonello, E.; Bossi, M.; Buzzoni, A.; Rodrigo, C.; Aerts, C.; Butler, C. J.; Guenther, E.; Hatzes, A.

    2005-01-01

    The GAUDI database (Ground-based Asteroseismology Uniform Database Interface) is a preparatory archive for the COROT (Convection, Rotation, and Planetary Transits) mission developed at the Laboratorio de Astrofísica Espacial y Física Fundamental (Laboratory for Space Astrophysics and Theoretical Physics, Spain). Its intention is to make the ground-based observations obtained in preparation of the asteroseismology program available in a simple and efficient way. It contains spectroscopic and photometric data together with inferred physical parameters for more than 1500 objects gathered since 1998 January 1998 in 6 years of observational campaigns. In this paper, the main functions and characteristics of the system are described. Based on observations collected at La Silla (ESO proposals 67.D-0169, 69.D-0166, and 70.D-0110), Telescopio Nazionale Galileo (proposal 6-20-068), Observatoire de Haute-Provence, the South African Astronomical Observatory, Tautenburg Observatory, and Sierra Nevada Observatory.

  4. Exploration of the brown dwarf regime around solar-like stars by CoRoT

    CERN Document Server

    Csizmadia, Szilárd

    2016-01-01

    Aims. A summary of the CoRoT brown dwarf investigations are presented. Methods. Transiting brown dwarfs around solar like stars were studied by using the photometric time-series of CoRoT, and ground based radial velocity measurements. Results. CoRoT detected three transiting brown dwarfs around F and G dwarf stars. The occurence rate of brown dwarfs was found to be 0.20 +/- 0.15% around solar-like stars which is compatible with the value obtained by Kepler-data.

  5. Transiting exoplanets from the CoRoT space mission XXV. CoRoT-27b: a massive and dense planet on a short-period orbit

    CERN Document Server

    Parviainen, H; Deleuil, M; Moutou, C; Deeg, H J; Ferraz-Mello, S; Samuel, B; Csizmadia, Sz; Pasternacki, T; Wuchterl, G; Havel, M; Fridlund, M; Agnus, R; Tingley, B; Aigrain, S; Almenara, J M; Alonso, R; Baglin, A; Barros, S; Bordé, A S P; Bouchy, F; Cabrera, J; Díaz, R; Dvorak, R; Erikson, A; Guillot, T; Hatzes, A; Hébrard, G; Mazeh, T; Montagnier, G; Ofir, A; Ollivier, M; Pätzold, M; Rauer, H; Rouan, D; Santerne, A; Schneider, J

    2014-01-01

    We report the discovery of a massive and dense transiting planet CoRoT-27b on a 3.58 day orbit around a 4.2 Gyr-old G2~star. The planet candidate was identified from the CoRoT photometry, and was confirmed as a planet with ground-based spectroscopy. The confirmation of the planet candidate is based on radial velocity observations combined with imaging to rule out blends. The characterisation of the planet and its host star is carried out using a Bayesian approach where all the data (CoRoT photometry, radial velocities, and spectroscopic characterisation of the star) are used jointly. The Bayesian analysis includes a study whether the assumption of white normally distributed noise holds for the CoRoT photometry, and whether the use of a non-normal noise distribution offers advantages in parameter estimation and model selection. CoRoT-27b has a mass of $10.39 \\pm 0.55$ $\\mathrm{M}_{\\rm Jup}$, a radius of $1.01 \\pm 0.04$ $\\mathrm{R}_{\\rm Jup}$, a mean density of $12.6_{-1.67}^{+1.92}$ $\\mathrm{g\\,cm^{-3}}$, and ...

  6. Loss of MeCP2 in the rat models regression, impaired sociability and transcriptional deficits of Rett syndrome.

    Science.gov (United States)

    Veeraragavan, Surabi; Wan, Ying-Wooi; Connolly, Daniel R; Hamilton, Shannon M; Ward, Christopher S; Soriano, Sirena; Pitcher, Meagan R; McGraw, Christopher M; Huang, Sharon G; Green, Jennie R; Yuva, Lisa A; Liang, Agnes J; Neul, Jeffrey L; Yasui, Dag H; LaSalle, Janine M; Liu, Zhandong; Paylor, Richard; Samaco, Rodney C

    2016-08-01

    Mouse models of the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) have advanced our understanding of Rett syndrome (RTT). RTT is a 'prototypical' neurodevelopmental disorder with many clinical features overlapping with other intellectual and developmental disabilities (IDD). Therapeutic interventions for RTT may therefore have broader applications. However, the reliance on the laboratory mouse to identify viable therapies for the human condition may present challenges in translating findings from the bench to the clinic. In addition, the need to identify outcome measures in well-chosen animal models is critical for preclinical trials. Here, we report that a novel Mecp2 rat model displays high face validity for modelling psychomotor regression of a learned skill, a deficit that has not been shown in Mecp2 mice. Juvenile play, a behavioural feature that is uniquely present in rats and not mice, is also impaired in female Mecp2 rats. Finally, we demonstrate that evaluating the molecular consequences of the loss of MeCP2 in both mouse and rat may result in higher predictive validity with respect to transcriptional changes in the human RTT brain. These data underscore the similarities and differences caused by the loss of MeCP2 among divergent rodent species which may have important implications for the treatment of individuals with disease-causing MECP2 mutations. Taken together, these findings demonstrate that the Mecp2 rat model is a complementary tool with unique features for the study of RTT and highlight the potential benefit of cross-species analyses in identifying potential disease-relevant preclinical outcome measures. © The Author 2016. Published by Oxford University Press.

  7. MeCP2基因热点突变分析在Rett综合征诊断中的应用%MeCP2 gene mutational hotspots in diagnosis of Rett syndrome

    Institute of Scientific and Technical Information of China (English)

    孟洪弟; 潘虹; 包新华; 王艳萍; 沈岩; 吴希如

    2002-01-01

    目的探讨MeCP2基因常见突变是否对Rett综合征临床诊断有帮助.方法对23例Rett综合征患儿,部分患儿家长和4名正常女性分别提取外周血基因组DNA.采用PCR方法扩增MeCP2基因第3外显子 nt22643~nt23022片段,限制性内切酶HphⅠ和Nla Ⅲ酶切分析T158M和R168X突变,6%聚丙烯酰胺凝胶电泳及银染检验酶切结果,突变点经DNA直接测序证实.结果 23例Rett 综合征患儿中4例有T158M突变,21例患儿中2例有R168X突变.在患儿双亲及正常女性对照均未发现以上2种突变.结论 T158M和R168X 2个突变在Rett综合征均较多发.PCR产物的限制酶分析,方法简便、快捷,有助于Rett综合征的临床诊断.

  8. A search for tight hierarchical triple systems amongst the eclipsing binaries in the CoRoT fields

    Science.gov (United States)

    Hajdu, T.; Borkovits, T.; Forgács-Dajka, E.; Sztakovics, J.; Marschalkó, G.; Benkő, J. M.; Klagyivik, P.; Sallai, M. J.

    2017-10-01

    We report a comprehensive search for hierarchical triple stellar system candidates amongst eclipsing binaries (EBs) observed by the CoRoT spacecraft. We calculate and check eclipse timing variation (ETV) diagrams for almost 1500 EBs in an automated manner. We identify five relatively short period Algol systems for which our combined light-curve and complex ETV analyses (including both the light-travel time effect and short-term dynamical third-body perturbations) resulted in consistent third-body solutions. The computed periods of the outer bodies are between 82 and 272 d (with an alternative solution of 831 d for one of the targets). We find that the inner and outer orbits are near coplanar in all but one case. The dynamical masses of the outer subsystems determined from the ETV analyses are consistent with both the results of our light-curve analyses and the spectroscopic information available in the literature. One of our candidate systems exhibits outer eclipsing events as well, the locations of which are in good agreement with the ETV solution. We also report another certain triply eclipsing triple system that, however, is lacking a reliable ETV solution due to the very short time range of the data, and four new blended systems (composite light curves of two EBs each), where we cannot decide whether the components are gravitationally bounded or not. Amongst these blended systems, we identify the longest period and highest eccentricity EB in the entire CoRoT sample.

  9. Reduction of Diaryldiselenides by System of Cp2TiCl2/ BuiMgBr/ THF and Its Application in Synthesis of Unsymmetrical Diaryl Selenides

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Reduction of diaryldiselenides by the system of Cp2TiCl2/BuiMgBr/THF gave the nucleophilic arylselenium complex. They reacted with diaryl iodonium salts to afford unsymmetrical diaryl selenides in high yields.

  10. Corotational Damping of Diskoseismic C-modes in Black Hole Accretion Discs

    CERN Document Server

    Tsang, David

    2008-01-01

    Diskoseismic c-modes in accretion discs have been invoked to explain low-frequency variabilities observed in black-hole X-ray binaries. These modes are trapped in the inner-most region of the disc and have frequencies much lower than the rotation frequency at the disc inner radius. We show that because the trapped waves can tunnel through the evanescent barrier to the corotational wave zone, the c-modes are damped due to wave absorption at the corotation resonance. We calculate the corotational damping rates of various c-modes using the WKB approximation. The damping rate varies widely depending on the mode frequency, the black hole spin parameter and the disc sound speed, and is generally much less than 10% of the mode frequency. A sufficiently strong excitation mechanism is needed to overcome this corotational damping and make the mode observable.

  11. Exoplanets versus brown dwarfs: the CoRoT view and the future

    CERN Document Server

    Schneider, Jean

    2016-01-01

    CoRoT has detected by transit several tens of objects whose radii run from 1.67 Earth radius. Their mass run from less than 5.7 Earth mass (CoRoT-24 b, Alonso et al. 2014) to 63 Jupiter mass (CoRoT-15 b, Bouchy et al. 2011). One could be tempted to think that more massive the object is, the larger it is in size and that there is some limit in mass and/or radius beyond which objects are not planets but very low mass stars below the 80 Jupiter mass limit to trigger nuclear fusion (namely "brown dwarfs" ). CoRoT findings contribute to the planet versus brown dwarf debate since there is no clear mass-radius relation.

  12. Transiting exoplanets from the CoRoT space mission. XXIII. CoRoT-21b: a doomed large Jupiter around a faint subgiant star

    DEFF Research Database (Denmark)

    Pätzold, M.; Endl, M.; Csizmadia, Sz.

    2012-01-01

    CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observ......CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow...

  13. Transiting exoplanets from the CoRoT space mission XVII. The hot Jupiter CoRoT-17b: a very old planet

    CERN Document Server

    Csizmadia, Sz; Deleuil, M; Cabrera, J; Fridlund, M; Gandolfi, D; Aigrain, S; Alonso, R; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Bruntt, H; Carone, L; Carpano, S; Cavarroc, C; Cochran, W; Deeg, H J; Diaz, R F; Dvorak, R; Endl, M; Erikson, A; Ferraz-Mello, S; Fruth, Th; Gazzano, J C; Gillon, M; Guenther, E W; Guillot, T; Hatzes, A; Havel, M; Hebrard, G; Jehin, E; Jorda, L; Leger, A; Llebaria, A; Lammer, H; Lovis, C; MacQueen, P J; Mazeh, T; Ollivier, M; Paetzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Tingley, B; Titz-Weider, R; Wuchterl, G

    2011-01-01

    We report on the discovery of a hot Jupiter-type exoplanet, CoRoT-17b, detected by the CoRoT satellite. It has a mass of $2.43\\pm0.30$\\Mjup and a radius of $1.02\\pm0.07$\\Rjup, while its mean density is $2.82\\pm0.38$ g/cm$^3$. CoRoT-17b is in a circular orbit with a period of $3.7681\\pm0.0003$ days. The host star is an old ($10.7\\pm1.0$ Gyr) main-sequence star, which makes it an intriguing object for planetary evolution studies. The planet's internal composition is not well constrained and can range from pure H/He to one that can contain $\\sim$380 earth masses of heavier elements.

  14. Hemoglobin switching in man and chicken is mediated by a heteromeric complex between the ubiquitous transcription factor CP2 and a developmentally specific protein.

    Science.gov (United States)

    Jane, S M; Nienhuis, A W; Cunningham, J M

    1995-01-03

    The human stage selector protein (SSP) has been implicated in the developmental regulation of the globin genes. Binding of SSP to the stage selector element (SSE) in the proximal gamma-globin promoter is integral to the competitive silencing of a linked beta-promoter in embryonic/fetal stage erythroleukemia (K562) cells. We now report the biochemical purification of SSP from K562 cell nuclear extract and demonstrate that the ubiquitously expressed transcription factor CP2 is pivotal to, but not sufficient for, SSP binding activity. Although addition of anti-CP2 antiserum disrupts the formation of the SSP-SSE complex in the electrophoretic mobility shift assay (EMSA), recombinant CP2 fails to bind to the SSE. Binding of CP2 to the SSE requires a heterodimeric partner present in K562 cells. We have defined the molecular weight of the partner protein as 40-45 kDa in UV and protein cross-linking experiments. An element analogous to the human SSE has previously been demonstrated in the chicken beta A-gene-promoter. The effects of this element are dependent on the binding of the chicken stage selector protein, NF-E4. Comparative studies between human CP2 and chicken NF-E4 demonstrate homology between the protein complexes. SSP binds to the chicken SSE and formation of this complex is ablated by the addition of anti-CP2 antiserum or a monoclonal antibody to NF-E4. Western analysis of partially purified NF-E4 using anti-CP2 antiserum or the NF-E4 monoclonal antibody both demonstrate a dominant band at 66 kDa. Similarly, the NF-E4 antibody recognizes the 66 kDa human CP2 protein in Western analysis of the SSP-SSE complex.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Biofiltration of trimethylamine, dimethylamine, and methylamine by immobilized Paracoccus sp. CP2 and Arthrobacter sp. CP1.

    Science.gov (United States)

    Ho, Kuo-Ling; Chung, Ying-Chien; Lin, Yueh-Hsien; Tseng, Ching-Ping

    2008-05-01

    A biofilter using granular activated carbon with immobilized Paracoccus sp. CP2 was applied to the elimination of 10-250 ppm of trimethylamine (TMA), dimethylamine (DMA), and methylamine (MA). The results indicated that the system effectively treated MA (>93%), DMA (>90%), and TMA (>85%) under high loading conditions, and the maximum degradation rates were 1.4, 1.2, and 0.9g-Nkg(-1) GAC d(-1). Among the three different amines treated, TMA was the most difficult to degrade and resulted in ammonia accumulation. Further study on TMA removal showed that the optimal pH was near neutral (6.0-8.0). The supply of high glucose (>0.1%) inhibited TMA removal, maybe due to substrate competition. However, complete TMA degradation was achieved under the co-immobilization of Paracoccus sp. CP2 and Arthrobacter sp. CP1 ( approximately 96%). Metabolite analysis results demonstrated that the metabolite NH(4)(+) concentrations decreased by a relatively small 27% while the metabolite NO(2)(-) apparently increased by heterotrophic nitrification of Arthrobacter sp. CP1 in the co-immobilization biofilter.

  16. Charge quantization and the Standard Model from the CP2 and CP3 nonlinear σ-models

    Science.gov (United States)

    Hellerman, Simeon; Kehayias, John; Yanagida, Tsutomu T.

    2014-04-01

    We investigate charge quantization in the Standard Model (SM) through a CP2 nonlinear sigma model (NLSM), SU(3/(SU(2×U(1), and a CP3 model, SU(4/(SU(3×U(1). We also generalize to any CPk model. Charge quantization follows from the consistency and dynamics of the NLSM, without a monopole or Grand Unified Theory, as shown in our earlier work on the CP1 model (arXiv:1309.0692). We find that representations of the matter fields under the unbroken non-abelian subgroup dictate their charge quantization under the U(1 factor. In the CP2 model the unbroken group is identified with the weak and hypercharge groups of the SM, and the Nambu-Goldstone boson (NGB) has the quantum numbers of a SM Higgs. There is the intriguing possibility of a connection with the vanishing of the Higgs self-coupling at the Planck scale. Interestingly, with some minor assumptions (no vector-like matter and minimal representations) and starting with a single quark doublet, anomaly cancellation requires the matter structure of a generation in the SM. Similar analysis holds in the CP3 model, with the unbroken group identified with QCD and hypercharge, and the NGB having the up quark as a partner in a supersymmetric model. This can motivate solving the strong CP problem with a vanishing up quark mass.

  17. Systemic delivery of MeCP2 rescues behavioral and cellular deficits in female mouse models of Rett syndrome.

    Science.gov (United States)

    Garg, Saurabh K; Lioy, Daniel T; Cheval, Hélène; McGann, James C; Bissonnette, John M; Murtha, Matthew J; Foust, Kevin D; Kaspar, Brian K; Bird, Adrian; Mandel, Gail

    2013-08-21

    De novo mutations in the X-linked gene encoding the transcription factor methyl-CpG binding protein 2 (MECP2) are the most frequent cause of the neurological disorder Rett syndrome (RTT). Hemizygous males usually die of neonatal encephalopathy. Heterozygous females survive into adulthood but exhibit severe symptoms including microcephaly, loss of purposeful hand motions and speech, and motor abnormalities, which appear after a period of apparently normal development. Most studies have focused on male mouse models because of the shorter latency to and severity in symptoms, yet how well these mice mimic the disease in affected females is not clear. Very few therapeutic treatments have been proposed for females, the more gender-appropriate model. Here, we show that self-complementary AAV9, bearing MeCP2 cDNA under control of a fragment of its own promoter (scAAV9/MeCP2), is capable of significantly stabilizing or reversing symptoms when administered systemically into female RTT mice. To our knowledge, this is the first potential gene therapy for females afflicted with RTT.

  18. Structural, Dynamical, and Energetical Consequences of Rett Syndrome Mutation R133C in MeCP2

    Directory of Open Access Journals (Sweden)

    Tugba G. Kucukkal

    2015-01-01

    Full Text Available Rett Syndrome (RTT is a progressive neurodevelopmental disease affecting females. RTT is caused by mutations in the MECP2 gene and various amino acid substitutions have been identified clinically in different domains of the multifunctional MeCP2 protein encoded by this gene. The R133C variant in the methylated-CpG-binding domain (MBD of MeCP2 is the second most common disease-causing mutation in the MBD. Comparative molecular dynamics simulations of R133C mutant and wild-type MBD have been performed to understand the impact of the mutation on structure, dynamics, and interactions of the protein and subsequently understand the disease mechanism. Two salt bridges within the protein and two critical hydrogen bonds between the protein and DNA are lost upon the R133C mutation. The mutation was found to weaken the interaction with DNA and also cause loss of helicity within the 141-144 region. The structural, dynamical, and energetical consequences of R133C mutation were investigated in detail at the atomic resolution. Several important implications of this have been shown regarding protein stability and hydration dynamics as well as its interaction with DNA. The results are in agreement with previous experimental studies and further provide atomic level understanding of the molecular origin of RTT associated with R133C variant.

  19. The intervening domain from MeCP2 enhances the DNA affinity of the methyl binding domain and provides an independent DNA interaction site

    Science.gov (United States)

    Claveria-Gimeno, Rafael; Lanuza, Pilar M.; Morales-Chueca, Ignacio; Jorge-Torres, Olga C.; Vega, Sonia; Abian, Olga; Esteller, Manel; Velazquez-Campoy, Adrian

    2017-01-01

    Methyl-CpG binding protein 2 (MeCP2) preferentially interacts with methylated DNA and it is involved in epigenetic regulation and chromatin remodelling. Mutations in MeCP2 are linked to Rett syndrome, the leading cause of intellectual retardation in girls and causing mental, motor and growth impairment. Unstructured regions in MeCP2 provide the plasticity for establishing interactions with multiple binding partners. We present a biophysical characterization of the methyl binding domain (MBD) from MeCP2 reporting the contribution of flanking domains to its structural stability and dsDNA interaction. The flanking disordered intervening domain (ID) increased the structural stability of MBD, modified its dsDNA binding profile from an entropically-driven moderate-affinity binding to an overwhelmingly enthalpically-driven high-affinity binding. Additionally, ID provided an additional site for simultaneously and autonomously binding an independent dsDNA molecule, which is a key feature linked to the chromatin remodelling and looping activity of MeCP2, as well as its ability to interact with nucleosomes replacing histone H1. The dsDNA interaction is characterized by an unusually large heat capacity linked to a cluster of water molecules trapped within the binding interface. The dynamics of disordered regions together with extrinsic factors are key determinants of MeCP2 global structural properties and functional capabilities. PMID:28139759

  20. Low-amplitude rotational modulation rather than pulsations in the CoRoT B-type supergiant HD 46769

    Science.gov (United States)

    Aerts, C.; Simón-Díaz, S.; Catala, C.; Neiner, C.; Briquet, M.; Castro, N.; Schmid, V. S.; Scardia, M.; Rainer, M.; Poretti, E.; Pápics, P. I.; Degroote, P.; Bloemen, S.; Østensen, R. H.; Auvergne, M.; Baglin, A.; Baudin, F.; Michel, E.; Samadi, R.

    2013-09-01

    Aims: We aim to detect and interpret photometric and spectroscopic variability of the bright CoRoT B-type supergiant target HD 46769 (V = 5.79). We also attempt to detect a magnetic field in the target. Methods: We analyse a 23-day oversampled CoRoT light curve after detrending and spectroscopic follow-up data using standard Fourier analysis and phase dispersion minimization methods. We determine the fundamental parameters of the star, as well as its abundances from the most prominent spectral lines. We perform a Monte Carlo analysis of spectropolarimetric data to obtain an upper limit of the polar magnetic field, assuming a dipole field. Results: In the CoRoT data, we detect a dominant period of 4.84 d with an amplitude of 87 ppm and some of its (sub-)multiples. Given the shape of the phase-folded light curve and the absence of binary motion, we interpret the dominant variability in terms of rotational modulation, with a rotation period of 9.69 d. Subtraction of the rotational modulation signal does not reveal any sign of pulsations. Our results are consistent with the absence of variability in the Hipparcos light curve. The spectroscopy leads to a projected rotational velocity of 72 ± 2 km s-1 and does not reveal periodic variability or the need to invoke macroturbulent line broadening. No signature of a magnetic field is detected in our data. A field stronger than ~500 G at the poles can be excluded, unless the possible non-detected field were more complex than dipolar. Conclusions: The absence of pulsations and macroturbulence of this evolved B-type supergiant is placed into the context of instability computations and of observed variability of evolved B-type stars. Based on CoRoT space-based photometric data; the CoRoT space mission was developed and operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. Based on observations collected at La Silla Observatory, ESO

  1. The high-energy environment in the super-earth system CoRoT-7

    CERN Document Server

    Poppenhaeger, K; Schröter, S; Lalitha, S; Kashyap, V; Schmitt, J H M M

    2012-01-01

    High-energy irradiation of exoplanets has been identified to be a key influence on the stability of these planets' atmospheres. So far, irradiation-driven mass-loss has been observed only in two Hot Jupiters, and the observational data remain even more sparse in the super-earth regime. We present an investigation of the high-energy emission in the CoRoT-7 system, which hosts the first known transiting super-earth. To characterize the high-energy XUV radiation field into which the rocky planets CoRoT-7b and CoRoT-7c are immersed, we analyzed a 25 ks XMM-Newton observation of the host star. Our analysis yields the first clear (3.5 sigma) X-ray detection of CoRoT-7. We determine a coronal temperature of ca. 3 MK and an X-ray luminosity of 3*10^28 erg/s. The level of XUV irradiation on CoRoT-7b amounts to ca. 37000 erg/cm^2/s. Current theories for planetary evaporation can only provide an order-of-magnitude estimate for the planetary mass loss; assuming that CoRoT-7b has formed as a rocky planet, we estimate that...

  2. Increased binding of MeCP2 to the GAD1 and RELN promoters may be mediated by an enrichment of 5-hmC in autism spectrum disorder (ASD) cerebellum.

    Science.gov (United States)

    Zhubi, A; Chen, Y; Dong, E; Cook, E H; Guidotti, A; Grayson, D R

    2014-01-21

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by symptoms related to altered social interactions/communication and restricted and repetitive behaviors. In addition to genetic risk, epigenetic mechanisms (which include DNA methylation/demethylation) are thought to be important in the etiopathogenesis of ASD. We studied epigenetic mechanisms underlying the transcriptional regulation of candidate genes in cerebella of ASD patients, including the binding of MeCP2 (methyl CpG binding protein-2) to the glutamic acid decarboxylase 67 (GAD1), glutamic acid decarboxylase 65 (GAD2), and Reelin (RELN) promoters and gene bodies. Moreover, we performed methyl DNA immunoprecipitation (MeDIP) and hydroxymethyl DNA immunoprecipitation (hMeDIP) to measure total 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in the same regions of these genes. The enrichment of 5-hmC and decrease in 5-mC at the GAD1 or RELN promoters detected by 5-hmC and 5-mC antibodies was confirmed by Tet-assisted bisulfite (TAB) pyrosequencing. The results showed a marked and significant increase in MeCP2 binding to the promoter regions of GAD1 and RELN, but not to the corresponding gene body regions in cerebellar cortex of ASD patients. Moreover, we detected a significant increase in TET1 expression and an enrichment in the level of 5-hmC, but not 5-mC, at the promoters of GAD1 and RELN in ASD when compared with CON. Moreover, there was increased TET1 binding to these promoter regions. These data are consistent with the hypothesis that an increase of 5-hmC (relative to 5-mC) at specific gene domains enhances the binding of MeCP2 to 5-hmC and reduces expression of the corresponding target genes in ASD cerebella.

  3. Expression of Dnmt1, demethylase, MeCP2 and methylation of tumor-related genes in human gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Jing-Yuan Fang; Zhong-Hua Cheng; Ying-Xuan Chen; Rong Lu; Li Yang; Hong-Yin Zhu; Lun-Gen Lu

    2004-01-01

    AIM: To explore the effect of DNA methyltransferase,demethylase and methyl-CpG binding protein MeCP2 on the expressions and methylation of hMSH2 and protooncogene in human gastric cancer.METHODS: Paired samples of primary gastric cancer and corresponding para-cancerous, non-cancerous gastric mucosae were obtained from surgically resected specimens of 28 patients. Transcription levels of Dnmt1, mbd2, MeCP2, p16INK4A,hMSH2 and c-myc were detected by using real-time PCR or RT-PCR. Promoter methylation of p16INK4A, c-myc and hMSH2 genes was assayed by methylation-specific PCR (MSP) and sequencing (mapping). Their relationships were analyzed by Fisher's exact test using the software SPSS. RESULTS: The average mRNA level of Dnmt1 gene from cancerous tissue was higher and that of mbd2 gene from cancerous tissue was lower than that from non-cancerous tissue, respectively. mbd2 was lower in cancerous tissue than in non-cancerous tissue in 14 (50.0%) of patients but higher in 3 cases (10.7%) of non-cancerous gastric tissue (P<0.001). c-myc expression was up-regulated in cancer tissues (P<0.05). The up-regulation of mbd2 was found in all patients with hypomethylated c-myc. The transcriptional levels of p16INK4A and MeCP2 genes did not display any differencebetween gastric cancerous and matched non-cancerous tissues. There were down-regulation and hypermethylation of hMSH2 in cancer tissues, and the hypermethylation of hMSH2 coexisted with down-regulated transcription.However, the transcription level of the above genes was not associated with biological behaviours of gastric cancers.CONCLUSION: The up-regulation of proto-oncogene may be the consequence of epigenetic control of gene expression by demethylase, and mbd2 is involved in the regulation of hMSH2 expression in human gastric cancer.

  4. Suprathermal helium associated with corotating interaction regions: A case study

    Science.gov (United States)

    Yu, J.; Berger, L.; Wimmer-Schweingruber, R. F.; Hilchenbach, M.; Kallenbach, R.; Klecker, B.; Guo, J.

    2016-03-01

    Enhancements of suprathermal particles observed at 1AU often can be related to Corotating Interaction Regions (CIRs). The compression regions associated with CIRs and their driven shocks which typically form at a few AU distance to the Sun can efficiently accelerate particles. If accelerated at the trailing edge of a CIR these particles can travel sunward along the ambient magnetic field and thus enhanced fluxes can be observed even if the acceleration region has passed over the spacecraft. We have analysed a CIR that has been observed at L1 by ACE/SWICS and SOHO/CELIAS/STOF on days 207 and 208 in 2003. The combination of SWICS and STOF data allowed us to study suprathermal Helium ranging from its onset at solar wind bulk energies up to 330 keV/nuc. Here we present our results for the temporal evolution of the flux, energy spectra and the He+/He++ ratio. In particular we present observational evidence for a turnover of the energy spectra at lower energies after the CIR passage which has been theoretically predicted but never been observed so far.

  5. Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius

    CERN Document Server

    Léger, A; Schneider, J; Barge, P; Fridlund, M; Samuel, B; Ollivier, M; Günther, E; Deleuil, M; Deeg, H J; Auvergne, M; Alonso, R; Aigrain, S; Alapini, A; Almenara, J M; Baglin, A; Barbieri, M; Bruntt, H; Borde, P; Bouchy, F; Cabrera, J; Catala, C; Carone, L; Carpano, S; Csizmadia, Sz; Dvorak, R; Erikson, A; Ferraz-Mello, S; Foing, B; Fressin, F; Gandolfi, D; Gillon, M; Gondoin, Ph; Grasset, O; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Lammer, H; Llebaria, A; Loeillet, B; Mayor, M; Mazeh, T; Moutou, C; Paetzold, M; Pont, F; Queloz, D; Rauer, H; Renner, S; Samadi, R; Shporer, A; Sotin, Ch; Tingley, B; Wuchterl, G

    2009-01-01

    We report the discovery of very shallow (DF/F = 3.4 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as due to the presence of a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods. We use CoRoT color information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy and preliminary results from Radial Velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star are derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. We examine carefully all conceivable cases of false positives, and all tests performed support the planetary hypothesis. Blends with separation larger than 0.40 arcsec or triple systems are almost excluded with a 8 10-4 ris...

  6. 异核金属多重键配合物Cp2 MM'(μ-C8 H8)的理论研究%Theoretical Study on the Heteronuclear Metal-metal Multiple Bond Complexes Cp2 MM'(μ-C8 H8)

    Institute of Scientific and Technical Information of China (English)

    刘楠楠; 丁益宏; 刘树萍

    2014-01-01

    The structure and bonding of the heteronuclear metal-metal multiple bond complexes Cp2 MM’(μ-C8 H8 ) ( MM’=ScMn, TiCr, ScCo, TiFe, VMn) were theoretically studied. The calculated results shows that: ( 1 ) for the 28 ve systems, the ground-state of Cp2 V2 (μ-C8 H8 ) is triplet state with V-V triple bond, the isoelectronic Cp2 TiCr (μ-C8 H8 ) is singlet state with Ti-Cr quadruple bond, and the isoelectronic species Cp2 ScMn(μ-C8 H8 ) is singlet state with Sc-Mn triple bond. (2) For the 30 valence electron systems, the ground-states of Cp2 Cr2 (μ-C8 H8 ) is singlet state with Cr-Cr triple bond, the isoelectronic species Cp2 VMn(μ-C8 H8 ) is triplet state with V-Mn single bond, while the isoelectronic species Cp2 ScCo(μ-C8 H8 ) and Cp2 TiFe (μ-C8 H8 ) are singlet states with double metal-metal bond. In the triplet state of Cp2 MM’(μ-C8 H8 ) , the two metal atoms are generally 17-electron configuration, while in the singlet state, the two metal atoms are generally respectively 16-and 18-electron configuration.%研究了双核金属多重键配合物Cp2 MM'(μ-C8 H8)( MM'=ScMn, TiCr, ScCo, TiFe, VMn, VV, CrCr)的结构和成键模式。计算结果表明,对于28价电子体系, Cp2 V2(μ-C8 H8)基态为含V-V三重键的三态构型,其等电子体Cp2 TiCr(μ-C8 H8)为Ti-Cr四重键的单态,等电子体Cp2 ScMn(μ-C8 H8)为Sc-Mn三重键的单态。对于30价电子体系, Cp2 Cr2(μ-C8 H8)基态为含Cr-Cr三重键的单态,等电子体Cp2 VMn(μ-C8 H8)为含V-Mn单键的三态,等电子体Cp2 ScCo(μ-C8 H8)和Cp2 TiFe(μ-C8 H8)为含Sc-Co和Ti-Fe双键的单态。在三态Cp2 MM'(μ-C8 H8)中,两个金属原子多为17电子构型,而单态结构中两种金属原子多分别为16和18电子构型。

  7. Influence of Organoboron Compounds on Ethylene Polymerization Using Cp2ZrCl2/MAO as Catalyst System

    Directory of Open Access Journals (Sweden)

    Luis Alexandro Valencia López

    2014-01-01

    Full Text Available Organoboron compounds of nonionic and ionic nature, tris(pentafluorophenylborane, and N,N-dimethylanilinium tetra(pentafluorophenylborate were evaluated to act in conjunction with MAO as activators on ethylene polymerization by using the catalyst Cp2ZrCl2. A decrease on the catalytic activity was observed in both cases in relation with a reference polyethylene which was synthesized in absence of any organoboron compound. An increase on the crystallinity degree and molecular weight, as well as an improvement in thermal and dynamic-mechanical properties, was observed in polyethylenes synthetized in presence of tris(pentafluorophenylborane. A low density polyethylene with improved thermal stability was obtained when N,N-dimethylanilinium tetra(pentafluorophenylborate was employed as activator.

  8. ANALYSIS OF RUBBER FORMING PROCESS OF FIRE BARRIER FROM TITANIUM CP2 ALLOY FOR AW 139 HELICOPTER

    Directory of Open Access Journals (Sweden)

    Mariusz Krakowski

    2015-05-01

    Full Text Available This paper presents conditions of forming products from titanium sheets by means of rubber stamping method. After introducing the issues connected with these elements manufacturing for aviation industry, considering standards and legal regulations, technological problems occurring during forming deep stiffening ribs. The results in the characteristic curvatures and distortion in the final products were generated in the process heterogeneous internal stress state. The Authors aimed at explaining and presenting of solutions limiting occurrence of chosen shape faults, which disqualify these products application in aviation industry. The proposed solutions significantly reduced the incidence of these unfavorable phenomena. The modified method of rubber stamping of firewall from titanium alloy CP-2 sheet was successfully implemented in manufacturing conditions of PZL Swidnik.

  9. Insulinotropic treatments exacerbate metabolic syndrome in mice lacking MeCP2 function.

    Science.gov (United States)

    Pitcher, Meagan R; Ward, Christopher S; Arvide, E Melissa; Chapleau, Christopher A; Pozzo-Miller, Lucas; Hoeflich, Andreas; Sivaramakrishnan, Manaswini; Saenger, Stefanie; Metzger, Friedrich; Neul, Jeffrey L

    2013-07-01

    Rett syndrome (RTT), an X-linked postnatal disorder, results from mutations in Methyl CpG-binding protein 2 (MECP2). Survival and breathing in Mecp2(NULL/Y) animals are improved by an N-terminal tripeptide of insulin-like growth factor I (IGF-I) treatment. We determined that Mecp2(NULL/Y) animals also have a metabolic syndrome and investigated whether IGF-I treatment might improve this phenotype. Mecp2(NULL/Y) mice were treated with a full-length IGF-I modified with the addition of polyethylene glycol (PEG-IGF-I), which improves pharmacological properties. Low-dose PEG-IGF-I treatment slightly improved lifespan and heart rate in Mecp2(NULL/Y) mice; however, high-dose PEG-IGF-I decreased lifespan. To determine whether insulinotropic off-target effects of PEG-IGF-I caused the detrimental effect, we treated Mecp2(NULL/Y) mice with insulin, which also decreased lifespan. Thus, the clinical benefit of IGF-I treatment in RTT may critically depend on the dose used, and caution should be taken when initiating clinical trials with these compounds because the beneficial therapeutic window is narrow.

  10. Effect of serum HE4 and CP2 contents on expression of clinical pathological molecules and proliferation molecules in tumor tissue of patients with endometrial carcinoma

    Institute of Scientific and Technical Information of China (English)

    Zhe Zhou; Xin Jiang; Ji-Cheng Song; Hong-Yan Jia

    2016-01-01

    Objective:To study the effect of serum HE4 and CP2 contents on the expression of clinical pathological molecules and proliferation molecules in tumor tissue of patients with endometrial carcinoma.Methods:A total of 40 cases of patients who were diagnosed with endometrial carcinoma in our hospital from May 2013 to March 2016 as well as 40 cases of healthy volunteers who received physical examination in our hospital during the same period were selected for study, serum samples were collected to detect HE4, c-myc, ZEB1, CP2, sTn, CA125, CA199 contents, and endometrial carcinoma tissue as well as para-carcinoma tissue were collected to detect P53, E-cad, EpCAM, C-erbB-2, Ki-67 and MACC1 contents.Results:Serum CP2 and HE4 contents of patients with endometrial carcinoma were significantly higher than those of healthy volunteers, and serum CP2 and HE4 contents of endometrial carcinoma patients with FIGO III-IV stage, low differentiation, muscular layer involvement more than 1/2 and cervical involvement were significantly higher than those of endometrial carcinoma patients with FIGO I-II stage, middle and high differentiation, muscular layer involvement less than 1/2 and without cervical involvement; serum CA125, CA199, c-myc, sTn and ZEB1 contents of patients with endometrial carcinoma were significantly higher than those of healthy volunteers and positively correlated with serum HE4 and CP2; P53 and E-cad contents in endometrial carcinoma tissue were significantly lower than those in para-carcinoma tissue and negatively correlated with serum HE4 and CP2, and EpCAM, C-erbB-2, Ki-67 and MACC1 contents were significantly higher than those in para-carcinoma tissue and positively correlated with serum HE4 and CP2.Conclusions:Serum HE4 and CP2 contents abnormally increase in patients with endometrial carcinoma, and serum HE4 and CP2 can be used to assess the clinical pathology of tumor as well as the degree of tumor tissue proliferation.

  11. Network models predict that reduced excitatory fluctuations can give rise to hippocampal network hyper-excitability in MeCP2-null mice.

    Directory of Open Access Journals (Sweden)

    Ernest C Y Ho

    Full Text Available Rett syndrome is a severe pediatric neurological disorder caused by loss of function mutations within the gene encoding methyl CpG-binding protein 2 (MeCP2. Although MeCP2 is expressed near ubiquitously, the primary pathophysiology of Rett syndrome stems from impairments of nervous system function. One alteration within different regions of the MeCP2-deficient brain is the presence of hyper-excitable network responses. In the hippocampus, such responses exist despite there being an overall decrease in spontaneous excitatory drive within the network. In this study, we generated and used mathematical, neuronal network models to resolve this apparent paradox. We did this by taking advantage of previous mathematical modelling insights that indicated that decreased excitatory fluctuations, but not mean excitatory drive, more critically explain observed changes in hippocampal network oscillations from MeCP2-null mouse slices. Importantly, reduced excitatory fluctuations could also bring about hyper-excitable responses in our network models. Therefore, these results indicate that diminished excitatory fluctuations may be responsible for the hyper-excitable state of MeCP2-deficient hippocampal circuitry.

  12. Coupling Between Corotation And Lindblad Mean Motion Resonances

    Science.gov (United States)

    El Moutamid, Maryame; Sicardy, B.; Renner, S.

    2012-10-01

    We consider the classical Elliptic Restricted Three-Body Problem with two bodies (particle and satellite) orbiting a central planet. If we take into account the oblateness of the central body through the classical additional terms up to J_6, the secular terms causing the orbit precessions appear in the disturbing potential leading to the presence of two critical resonant arguments : Φ = (m+1)λ‧ + mλ + ω and Φ‧ = (m+1)λ‧ + mλ + ω‧ where m is an integer, λ and ω the mean longitude and the longitude of the periapsis of the particle, and the primed quantities apply to the satellite. The arguments Φ‧ and Φ respectively describe the Corotation Eccentric Resonance (CER) and the Lindblad Eccentric Resonance (LER). We developed a new model (the CoraLin model) which encapsulate in a simple adimensional form the coupling between the two resonances. We examine the asymptotic configurations where these resonances are well separated or completely superimposed. Poincaré surfaces of section reveal that in intermediate cases, the strong coupling between the resonances may lead to chaotic behavior. We apply this model to several recently discovered small Saturnian satellites dynamically linked to Mimas through first mean motion resonances : Anthe, Methone, and Aegaeon, all associated with arc material. All satellites are trapped in CER with Mimas and perturbed by the associated LER. We estimate the probability of capturing a satellite into a of CER with Mimas, as the orbit of the latter evolves through tidal effects, and discuss possible scenarios for the the dynamical origin of those moons.

  13. CoRoT-7 b: Super-Earth or Super-Io?

    CERN Document Server

    Barnes, Rory; Greenberg, Richard; Jackson, Brian; Kaib, Nathan A

    2009-01-01

    CoRoT-7 b, a planet about 70% larger than the Earth orbiting a Sun-like star, is the first-discovered rocky exoplanet, and hence has been dubbed a "super-Earth". Some initial studies suggested that since the planet is so close to its host star, it receives enough insolation to partially melt its surface. However, these past studies failed to take into consideration the role that tides may play in this system. Even if the planet's eccentricity has always been zero, we show that tidal decay of semi-major axis could have been large enough that the planet formed on a wider orbit which received less insolation. Moreover, CoRoT-7 b could be tidally heated at a rate that dominates its geophysics and drives extreme volcanism. In this case, CoRoT-7 b is a "super-Io" that, like Jupiter's volcanic moon, is dominated by volcanism and rapid resurfacing. Such heating could occur with an eccentricity of just 10^-5. This small value could be driven by CoRoT-7 c if its own eccentricity is larger than ~10^-4. CoRoT-7 b may be ...

  14. Synthesis and crystal structure of the trimetallic erbium tetrahydride complex[Li(THF)4][{(ButCp)2Er(μ-H)}3-(μ3-H)

    Institute of Scientific and Technical Information of China (English)

    YAO Yingming; SONG Sheping; SHEN Qi; HU Jingyu; LIN Yonghua

    2004-01-01

    Reaction of [(ButCp)2Er(. Μ-Cl)]2 with ButLi in 1: 1 molar ratio in THF at -78C, after work-up, afforded the trimetallic erbium tetrahydride complex [Li(THF)4][{(ButCp)2Er(μ-H)}3(μ3-H)] (1) by β-hydrogen elimination reaction. Crystal structure determination reveals that complex 1 has discrete ion pair structure. The anion is composed of three (ButCp)2Er units to form a triangle array connected by three bridged hydrogen atoms, and the fourth hydrogen atom coordinated to three Er3+ ions. The coordination number for each Er3+ ion is 9.

  15. Reaction of BH4- with [Mo2Cp2(mu-SMe)n] species to give tetrahydroborato, hydrido or dimetallaborane compounds: control of product by ancillary ligands.

    Science.gov (United States)

    Cabon, Nolwenn; Petillon, Francois Y; Schollhammer, Philippe; Talarmin, Jean; Muir, Kenneth W

    2004-09-07

    The reaction of mono- or dichloro-dimolybdenum(III) complexes [Mo2Cp2(mu-SMe)2(mu-Cl)(mu-Y)] (Cp=eta5-C5H5; 1, Y=SMe; 2, Y=PPh2; 3, Y=Cl) with NaBH4 at room temperature gave in high yields tetrahydroborato (8), hydrido (9) or metallaborane (12) complexes depending on the ancillary ligands. The correct formulation of derivatives and has been unambigously determined by X-ray diffraction methods. That of the hydrido compound 9 has been established in solution by NMR analysis and confirmed by an X-ray study of the mu-azavinylidene derivative [Mo2Cp2(mu-SMe)2(mu-PPh2)(mu-N=CHMe)] (10) obtained from the insertion of acetonitrile into the Mo-H bond of 9. Reaction of NaBH4 with nitrile derivatives, [Mo2Cp2(mu-SMe)4-n(CH3CN)2n]n+(5, n=1; 6 n=2), afforded the tetrahydroborato compound 8, together with a mu-azavinylidene species [Mo2Cp2(mu-SMe)3(mu-N=CHMe)](14), when n=1, and the metallaborane complex 12, together with a mixed borohydrato-azavinylidene derivative [Mo2Cp2(mu-SMe)2(mu-BH4)(mu-N=CHMe)] (13), when n=2. The molecular structures of these complexes have been confirmed by X-ray analysis. Preparations of some of the starting complexes (3 and 4) are also described, as are the molecular structures of the precursors [Mo2Cp2(mu-SMe)2(mu-X)(mu-Y)] (1, X/Y=Cl/SMe; 2, X/Y=Cl/PPh2; 4, X/Y=SMe/PPh2).

  16. Solution structure of a Plasmodium falciparum AMA-1/MSP 1 chimeric protein vaccine candidate (PfCP-2.9 for malaria

    Directory of Open Access Journals (Sweden)

    Jin Changwen

    2010-03-01

    Full Text Available Abstract Background The Plasmodium falciparum chimeric protein PfCP-2.9 is a promising asexual-stage malaria vaccine evaluated in clinical trials. This chimeric protein consists of two cysteine-rich domains: domain III of the apical membrane antigen 1 (AMA-1 [III] and the C-terminal region of the merozoite surface protein 1 (MSP1-19. It has been reported that the fusion of these two antigens enhanced their immunogenicity and antibody-mediated inhibition of parasite growth in vitro. Methods The 15N-labeled and 13C/15N-labeled PfCP-2.9 was produced in Pichia pastoris for nuclear magnetic resonance (NMR structure analysis. The chemical shift assignments of PfCP-2.9 were compared with those previously reported for the individual domains (i.e., PfAMA-1(III or PfMSP 1-19. The two-dimensional spectra and transverse relaxation rates (R2 of the PfMSP1-19 alone were compared with that of the PfCP-2.9. Results Confident backbone assignments were obtained for 122 out of 241 residues of PfCP-2.9. The assigned residues in PfCP-2.9 were very similar to those previously reported for the individual domains. The conformation of the PfMSP1-19 in different constructs is essentially the same. Comparison of transverse relaxation rates (R2 strongly suggests no weak interaction between the domains. Conclusions These data indicate that the fusion of AMA-1(III and MSP1-19 as chimeric protein did not change their structures, supporting the use of the chimeric protein as a potential malaria vaccine.

  17. A new synthetic entry to phosphinophosphinidene complexes. Synthesis and structural characterisation of the first side-on bonded and the first terminally bonded phosphinophosphinidene zirconium complexes [mu-(1,2:2-eta-tBu2P=P)[Zr(Cl)Cp2]2] and [[Zr(PPhMe2)Cp2](eta1)-P-PtBu2)].

    Science.gov (United States)

    Pikies, Jerzy; Baum, Elke; Matern, Eberhard; Chojnacki, Jaroslaw; Grubba, Rafal; Robaszkiewicz, Andrzej

    2004-11-07

    The reactions of lithiated diphosphanes with transition metal chlorides constitute a new general entry to phosphinophosphinidene complexes: the reaction of Cp2ZrCl2(Cp = C5H5) with tBu2P-P(SiMe3)Li (molar ratio approximately 1:1) yields [mu-(1,2:2-eta-tBu2P=P)[Zr(Cl)Cp2]2]; the reaction of Cp2ZrCl2 with tBu2P-P(SiMe3)Li (molar ratio approximately 1:2) and an excess of PPhMe2 in DME yields the first terminally bonded phosphinophosphinidene complex, [[Zr(PPhMe2)Cp2](eta1-P-PtBu2)].

  18. Fetal alcohol exposure alters proopiomelanocortin gene expression and hypothalamic-pituitary-adrenal axis function via increasing MeCP2 expression in the hypothalamus.

    Directory of Open Access Journals (Sweden)

    Omkaram Gangisetty

    Full Text Available Proopiomelanocortin (POMC is a precursor gene of the neuropeptide β-endorphin in the hypothalamus and is known to regulate various physiological functions including stress response. Several recent reports showed that fetal alcohol exposure programs the hypothalamus to produce lower levels of POMC gene transcripts and to elevate the hypothalamic-pituitary-adrenal (HPA axis response to stressful stimuli. We investigated the role of methyl CpG binding protein (MeCP2 in the effects of prenatal ethanol on POMC gene expression and hypothalamic-pituitary-adrenal (HPA axis function. Pregnant Sprague Dawley rats were fed between GD 7 and 21 with a liquid diet containing 6.7% alcohol, pair-fed with isocaloric liquid diet, or fed ad libitum with rat chow, and their male offsprings were used at 60 days after birth in this study. Fetal alcohol exposure reduced the level of POMC mRNA, but increased the level of DNA methylation of this gene in the arcuate nucleus (ARC of the hypothalamus where the POMC neuronal cell bodies are located. Fetal alcohol exposed rats showed a significant increase in MeCP2 protein levels in POMC cells, MeCP2 gene transcript levels as well as increased MeCP2 protein binding on the POMC promoter in the arcuate nucleus. Lentiviral delivery of MeCP2 shRNA into the third ventricle efficiently reduced MeCP2 expression and prevented the effect of prenatal ethanol on POMC gene expression in the arcuate nucleus. MeCP2-shRNA treatment also normalized the prenatal ethanol-induced increase in corticotropin releasing hormone (CRH gene expression in the hypothalamus and elevated plasma adrenocorticotrophic hormone (ACTH and corticosterone hormone responses to lipopolysaccharide (LPS challenge. These results suggest that fetal alcohol programming of POMC gene may involve recruitment of MeCP2 on to the methylated promoter of the POMC gene to suppress POMC transcript levels and contribute to HPA axis dysregulation.

  19. Study of HD 169392A observed by CoRoT and HARPS

    CERN Document Server

    Mathur, S; Catala, C; Benomar, O; Davies, G R; Garcia, R A; Salabert, D; Ballot, J; Mosser, B; Regulo, C; Chaplin, W J; Elsworth, Y; Handberg, R; Hekker, S; Mantegazza, L; Michel, E; Poretti, E; Rainer, M; Roxburgh, I W; Samadi, R; Steslicki, M; Uytterhoeven, K; Verner, G A; Auvergne, M; Baglin, A; Forteza, S Barcelo; Baudin, F; Cortes, T Roca

    2012-01-01

    The numerous results obtained with asteroseismology thanks to space missions such as CoRoT and Kepler are providing a new insight on stellar evolution. After five years of observations, CoRoT is going on providing high-quality data. We present here the analysis of the double star HD169392 complemented by ground-based spectroscopic observations. This work aims at characterizing the fundamental parameters of the two stars, their chemical composition, the acoustic-mode global parameters including their individual frequencies, and their dynamics. We have analysed HARPS observations of the two stars to retrieve their chemical compositions. Several methods have been used and compared to measure the global properties of acoustic modes and their individual frequencies from the photometric data of CoRoT. The new spectroscopic observations and archival astrometric values suggest that HD169392 is a wide binary system weakly bounded. We have obtained the spectroscopic parameters for both components, suggesting the origin...

  20. Radial velocity follow-up of CoRoT transiting exoplanets

    Directory of Open Access Journals (Sweden)

    Deleuil M.

    2011-02-01

    Full Text Available We report on the results from the radial-velocity follow-up program performed to establish the planetary nature and to characterize the transiting candidates discovered by the space mission CoRoT. We use the SOPHIE at OHP, HARPS at ESO and the HIRES at Keck spectrographs to collect spectra and high-precision radial velocity (RV measurements for several dozens different candidates from CoRoT. We have measured the Rossiter-McLaughlin effect of several confirmed planets, especially CoRoT-1b which revealed that it is another highly inclined system. Such high-precision RV data are necessary for the discovery of new transiting planets. Furthermore, several low mass planet candidates have emerged from our Keck and HARPS data.

  1. Existence of a component corotating with the earth in high-latitude disturbance magnetic fields

    Science.gov (United States)

    Suzuki, A.; Kim, J. S.; Sugiura, M.

    1982-01-01

    A study of the data from the high-latitude North American IMS network of magnetic stations suggests that there is a component in substorm perturbations that corotates with the earth. It is as yet not certain whether the existence of this component stems from the corotation of a part of the magnetospheric plasma involved in the substorm mechanism or if it is a 'phase change' resulting from the control of the substorm manifestations by the earth's main magnetic field which is not axially symmetric. There are other geophysical phenomena showing a persistence of longitudinal variations corotating with the earth. These phenomena are of significance for a better understanding of ionosphere-magnetosphere coupling.

  2. The NStED Periodogram Service and Interface for Public CoRoT Data

    CERN Document Server

    von Braun, K; Beekley, A; Berriman, G B; Bryden, G; Chan, B; Ciardi, D R; Good, J; Harbut, M; Kane, S R; Laity, A; Lau, C; Lynn, M; McElroy, D; Plavchan, P; Regelson, M; Rey, R; Ramirez, S V; Stauffer, J; Zhang, A

    2011-01-01

    As part of the NASA-CNES agreement, the NASA Star and Exoplanet Database (NStED) serves as the official US portal for the public CoRoT data products. NStED is a general purpose archive with the aim of providing support for NASA's planet finding and characterization goals. Consequently, the NASA Exoplanet Science Institute (NExScI) developed, and NStED adapted, a periodogram service for CoRoT data to determine periods of variability phenomena and create phased photometric light curves. Through the NStED periodogram interface, the user may choose three different period detection algorithms to use on any photometric time series product, or even upload and analyze their own data. Additionally, the NStED periodogram is remotely accessed by the CoRoT archive as part of its interface. NStED is available at {\\bf http://nsted.ipac.caltech.edu}.

  3. Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities

    CERN Document Server

    Faria, J P; Brewer, B J; Figueira, P; Oshagh, M; Santerne, A; Santos, N C

    2016-01-01

    Stellar activity can induce signals in the radial velocities of stars, complicating the detection of orbiting low-mass planets. We present a method to determine the number of planetary signals present in radial-velocity datasets of active stars, using only radial-velocity observations. Instead of considering separate fits with different number of planets, we use a birth-death Markov chain Monte Carlo algorithm to infer the posterior distribution for the number of planets in a single run. In a natural way, the marginal distributions for the orbital parameters of all planets are also inferred. This method is applied to HARPS data of CoRoT-7. We confidently recover both CoRoT-7b and CoRoT-7c although the data show evidence for additional signals.

  4. Corotation resonance and overstable oscillations in black-hole accretion discs: general-relativistic calculations

    CERN Document Server

    Horak, Jiri

    2013-01-01

    We study the dynamics of spiral waves and oscillation modes in relativistic rotating discs around black holes. Generalizing the Newtonian theory, we show that wave absorption can take place at the corotation resonance, where the pattern frequency of the wave matches the background disc rotation rate. We derive the general relativistic expression for the disc vortensity (vorticity divided by surface density), which governs the behaviour of density perturbation near corotation. Depending on the gradient of the generalized disc vortensity, corotational wave absorption can lead to the amplification or damping of the spiral wave. We apply our general theory of relativistic wave dynamics to calculate the non-axisymmetric inertial-acoustic modes (also called p-modes) trapped in the inner-most region of a black hole accretion disc. Because general relativity changes the profiles of the radial epicyclic frequency and disc vortensity near the inner disc edge close to the black hole, these p-modes can become overstable ...

  5. The study of Be stars with the CoRoT satellite

    Science.gov (United States)

    Diago, P. D.; Gutierrez-Soto, J.; Fabregat, J.; Suso, J.; COROT Be Team

    2011-11-01

    The CoRoT space mission, launched in December 2006, is a spacecraft devoted to the study of the stellar interiors and the exo-planet search. Concerning the seismology of the Be stars, the presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars. In this field, the CoRoT satellite is providing data with an unprecedent quality and precision that is confirming non-radial pulsations in Be stars. The CoRoT Be Team is an international collaboration composed by members from France, Spain, Brazil and Belgium and is in charge of the exploitation and analysis of the Be stars data. In this work we present the highlighted results of the observed Be stars by CoRoT and the future prospects of the CoRoT Be Team. These results include the detection of the Be star HD 49 330 during an outburst phase and the measurement of the change in the oscillation spectrum during this rare event. These observations gave insight into the nature of the explosion. It will help to solve a question that has been pending for years: are oscillations the cause of the outbursts? Moreover, for the first time, the CoRoT satellite has detected simultaneously the rotational and the pulsational frequencies for the Be star HD 50 209, which constitutes a proof of the presence of pulsations in the Be stars. %J Highlights of Spanish Astrophysics VI, Proceedings of the IX Scientific Meeting of the Spanish Astronomical Society (SEA), held in Madrid, September 13 - 17, 2010, Eds.: M. R. Zapatero Osorio, J. Gorgas, J. Maiz Apellaniz, J. R. Pardo, and A. Gil de Paz., p. 531-531

  6. Transiting exoplanets from the CoRoT space mission. XXVII. CoRoT-28b, a planet orbiting an evolved star, and CoRoT-29b, a planet showing an asymmetric transit

    Science.gov (United States)

    Cabrera, J.; Csizmadia, Sz.; Montagnier, G.; Fridlund, M.; Ammler-von Eiff, M.; Chaintreuil, S.; Damiani, C.; Deleuil, M.; Ferraz-Mello, S.; Ferrigno, A.; Gandolfi, D.; Guillot, T.; Guenther, E. W.; Hatzes, A.; Hébrard, G.; Klagyivik, P.; Parviainen, H.; Pasternacki, Th.; Pätzold, M.; Sebastian, D.; Tadeu dos Santos, M.; Wuchterl, G.; Aigrain, S.; Alonso, R.; Almenara, J.-M.; Armstrong, J. D.; Auvergne, M.; Baglin, A.; Barge, P.; Barros, S. C. C.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Carpano, S.; Chaffey, C.; Deeg, H. J.; Díaz, R. F.; Dvorak, R.; Erikson, A.; Grziwa, S.; Korth, J.; Lammer, H.; Lindsay, C.; Mazeh, T.; Moutou, C.; Ofir, A.; Ollivier, M.; Pallé, E.; Rauer, H.; Rouan, D.; Samuel, B.; Santerne, A.; Schneider, J.

    2015-07-01

    Context. We present the discovery of two transiting extrasolar planets by the satellite CoRoT. Aims: We aim at a characterization of the planetary bulk parameters, which allow us to further investigate the formation and evolution of the planetary systems and the main properties of the host stars. Methods: We used the transit light curve to characterize the planetary parameters relative to the stellar parameters. The analysis of HARPS spectra established the planetary nature of the detections, providing their masses. Further photometric and spectroscopic ground-based observations provided stellar parameters (log g, Teff, v sin i) to characterize the host stars. Our model takes the geometry of the transit to constrain the stellar density into account, which when linked to stellar evolutionary models, determines the bulk parameters of the star. Because of the asymmetric shape of the light curve of one of the planets, we had to include the possibility in our model that the stellar surface was not strictly spherical. Results: We present the planetary parameters of CoRoT-28b, a Jupiter-sized planet (mass 0.484 ± 0.087 MJup; radius 0.955 ± 0.066 RJup) orbiting an evolved star with an orbital period of 5.208 51 ± 0.000 38 days, and CoRoT-29b, another Jupiter-sized planet (mass 0.85 ± 0.20 MJup; radius 0.90 ± 0.16 RJup) orbiting an oblate star with an orbital period of 2.850 570 ± 0.000 006 days. The reason behind the asymmetry of the transit shape is not understood at this point. Conclusions: These two new planetary systems have very interesting properties and deserve further study, particularly in the case of the star CoRoT-29. The CoRoT space mission, launched on December 27th 2006, was developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany, and Spain. Based on observations obtained with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland

  7. Response of Earth and Venus ionospheres to corotating solar wind stream of 3 July 1979

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, H.A. Jr.; Cloutier, P.A.; Dryer, M.; Suess, S.T.; Barnes, A.; Wolff, R.S.

    1985-06-01

    Corotating solar wind streams emanating from stable coronal structures provide an unique opportunity to compare the response of planetary ionospheres to the energy conveyed in the streams. For recurrent solar conditions the signal propagating outward along spiral paths in interplanetary space can at times exhibit rather similar content at quite different downstream locations in the ecliptic plane. Using solar wind measurements from plasma detectors on ISEE-3, Pioneer Venus Orbiter (PVO) and Helios-A, as well as in-situ ion composition measurements from Bennett Ion Mass Spectrometers on the Atmosphere Explorer-E and PVO spacecraft, corotating stream interactions are examined at Earth and Venus.

  8. VLT transit and occultation photometry for the bloated planet CoRoT-1b

    OpenAIRE

    Gillon, Michaël; Demory, B. -O.; Triaud, A. H. M. J.; Barman, T; Hebb, L.; Montalban Iglesias, Josefa; Maxted, P.; Queloz, D; Deleuil, M.; Magain, Pierre

    2009-01-01

    We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and 1.45 (+0.07,-0.13) R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we ...

  9. VizieR Online Data Catalog: Corot photometry of TYC 455-791-1 (Strassmeier+, 2017)

    Science.gov (United States)

    Strassmeier, K. G.; Granzer, T.; Mallonn, M.; Weber, M.; Weingrill, J.

    2016-11-01

    From the original CoRoT white-light flux obtained on two consecutive runs, we filter out obvious outliers from the SAA (south Atlantic Anomaly). The third column are the remaining CoRoT data points. The two data set were merged using individual zero-points of 716386.54e- for the first data set and 721882.56e- for the second data set, respectively. The magnitudes thus calculates are in column four. The last column is the combined model of the transit plus a 12th order Fourier-series fit to the out-of-transit data. (1 data file).

  10. Multiple star systems observed with CoRoT and Kepler

    Directory of Open Access Journals (Sweden)

    Southworth John

    2015-01-01

    Full Text Available The CoRoT and Kepler satellites were the first space platforms designed to perform high-precision photometry for a large number of stars. Multiple systems display a wide variety of photometric variability, making them natural benefactors of these missions. I review the work arising from CoRoT and Kepler observations of multiple systems, with particular emphasis on eclipsing binaries containing giant stars, pulsators, triple eclipses and/or low-mass stars. Many more results remain untapped in the data archives of these missions, and the future holds the promise of K2, TESS and PLATO.

  11. Multiple star systems observed with CoRoT and Kepler (invited review)

    CERN Document Server

    Southworth, John

    2014-01-01

    The CoRoT and Kepler satellites were the first space platforms designed to perform high-precision photometry for a large number of stars. Multiple systems display a wide variety of photometric variability, making them natural benefactors of these missions. I review the work arising from CoRoT and Kepler observations of multiple systems, with particular emphasis on eclipsing binaries containing giant stars, pulsators, triple eclipses and/or low-mass stars. Many more results remain untapped in the data archives of these missions, and the future holds the promise of K2, TESS and PLATO.

  12. The Adaptive Buffered Force QM/MM method in the CP2K and AMBER software packages

    CERN Document Server

    Mones, Letif; Götz, Andreas W; Laino, Teodoro; Walker, Ross C; Leimkuhler, Ben; Csányi, Gábor; Bernstein, Noam

    2014-01-01

    The implementation and validation of the adaptive buffered force QM/MM method in two popular packages, CP2K and AMBER are presented. The implementations build on the existing QM/MM functionality in each code, extending it to allow for redefinition of the QM and MM regions during the simulation and reducing QM-MM interface errors by discarding forces near the boundary according to the buffered force-mixing approach. New adaptive thermostats, needed by force-mixing methods, are also implemented. Different variants of the method are benchmarked by simulating the structure of bulk water, water autoprotolysis in the presence of zinc and dimethyl-phosphate hydrolysis using various semiempirical Hamiltonians and density functional theory as the QM model. It is shown that with suitable parameters, based on force convergence tests, the adaptive buffered-force QM/MM scheme can provide an accurate approximation of the structure in the dynamical QM region matching the corresponding fully QM simulations, as well as reprod...

  13. Layered hydrogels accelerate iPSC-derived neuronal maturation and reveal migration defects caused by MeCP2 dysfunction

    Science.gov (United States)

    Zhang, Zhen-Ning; Freitas, Beatriz C.; Qian, Hao; Lux, Jacques; Acab, Allan; Trujillo, Cleber A.; Herai, Roberto H.; Nguyen Huu, Viet Anh; Wen, Jessica H.; Joshi-Barr, Shivanjali; Karpiak, Jerome V.; Engler, Adam J.; Fu, Xiang-Dong; Muotri, Alysson R.; Almutairi, Adah

    2016-03-01

    Probing a wide range of cellular phenotypes in neurodevelopmental disorders using patient-derived neural progenitor cells (NPCs) can be facilitated by 3D assays, as 2D systems cannot entirely recapitulate the arrangement of cells in the brain. Here, we developed a previously unidentified 3D migration and differentiation assay in layered hydrogels to examine how these processes are affected in neurodevelopmental disorders, such as Rett syndrome. Our soft 3D system mimics the brain environment and accelerates maturation of neurons from human induced pluripotent stem cell (iPSC)-derived NPCs, yielding electrophysiologically active neurons within just 3 wk. Using this platform, we revealed a genotype-specific effect of methyl-CpG-binding protein-2 (MeCP2) dysfunction on iPSC-derived neuronal migration and maturation (reduced neurite outgrowth and fewer synapses) in 3D layered hydrogels. Thus, this 3D system expands the range of neural phenotypes that can be studied in vitro to include those influenced by physical and mechanical stimuli or requiring specific arrangements of multiple cell types.

  14. Transiting exoplanets from the CoRoT space mission. XVIII. CoRoT-18b: a massive hot Jupiter on a prograde, nearly aligned orbit

    Science.gov (United States)

    Hébrard, G.; Evans, T. M.; Alonso, R.; Fridlund, M.; Ofir, A.; Aigrain, S.; Guillot, T.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carone, L.; Carpano, S.; Cavarroc, C.; Csizmadia, Sz.; Deeg, H. J.; Deleuil, M.; Díaz, R. F.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Gandolfi, D.; Gibson, N.; Gillon, M.; Guenther, E.; Hatzes, A.; Havel, M.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Mazeh, T.; Moutou, C.; Ollivier, M.; Parviainen, H.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Santerne, A.; Schneider, J.; Tingley, B.; Wuchterl, G.

    2011-09-01

    We report the detection of CoRoT-18b, a massive hot Jupiter transiting in front of its host star with a period of 1.9000693 ± 0.0000028 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite combined with spectroscopic and photometric ground-based follow-up observations. The planet has a mass Mp = 3.47 ± 0.38 MJup, a radius Rp = 1.31 ± 0.18 RJup, and a density ρp = 2.2 ± 0.8 g cm-3. It orbits a G9V star with a mass M⋆ = 0.95 ± 0.15 M⊙, a radius R⋆ = 1.00 ± 0.13 R⊙, and arotation period Prot = 5.4 ± 0.4 days. The age of the system remains uncertain, with stellar evolution models pointing either to a few tens Ma or several Ga, while gyrochronology and lithium abundance point towards ages of a few hundred Ma. This mismatch potentially points to a problem in our understanding of the evolution of young stars, with possibly significant implications for stellar physics and the interpretation of inferred sizes of exoplanets around young stars. We detected the Rossiter-McLaughlin anomaly in the CoRoT-18 system thanks to the spectroscopic observation of a transit. We measured the obliquity ψ = 20° ± 20° (sky-projected value λ = -10° ± 20°), indicating that the planet orbits in the same way as the star is rotating and that this prograde orbit is nearly aligned with the stellar equator. The CoRoT space mission, launched on 2006 December 27, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain.Table 2 is available in electronic form at http://www.aanda.org

  15. Transiting exoplanets from the CoRoT space mission. XX. CoRoT-20b: A very high density, high eccentricity transiting giant planet

    Science.gov (United States)

    Deleuil, M.; Bonomo, A. S.; Ferraz-Mello, S.; Erikson, A.; Bouchy, F.; Havel, M.; Aigrain, S.; Almenara, J.-M.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.; Bordé, P.; Bruntt, H.; Cabrera, J.; Carpano, S.; Cavarroc, C.; Csizmadia, Sz.; Damiani, C.; Deeg, H. J.; Dvorak, R.; Fridlund, M.; Hébrard, G.; Gandolfi, D.; Gillon, M.; Guenther, E.; Guillot, T.; Hatzes, A.; Jorda, L.; Léger, A.; Lammer, H.; Mazeh, T.; Moutou, C.; Ollivier, M.; Ofir, A.; Parviainen, H.; Queloz, D.; Rauer, H.; Rodríguez, A.; Rouan, D.; Santerne, A.; Schneider, J.; Tal-Or, L.; Tingley, B.; Weingrill, J.; Wuchterl, G.

    2012-02-01

    We report the discovery by the CoRoT space mission of a new giant planet, CoRoT-20b. The planet has a mass of 4.24 ± 0.23 MJup and a radius of 0.84 ± 0.04 RJup. With a mean density of 8.87 ± 1.10 g cm-3, it is among the most compact planets known so far. Evolutionary models for the planet suggest a mass of heavy elements of the order of 800 M⊕ if embedded in a central core, requiring a revision either of the planet formation models or both planet evolution and structure models. We note however that smaller amounts of heavy elements are expected by more realistic models in which they are mixed throughout the envelope. The planet orbits a G-type star with an orbital period of 9.24 days and an eccentricity of 0.56.The star's projected rotational velocity is vsini = 4.5 ± 1.0 km s-1, corresponding to a spin period of 11.5 ± 3.1 days if its axis of rotation is perpendicular to the orbital plane. In the framework of Darwinian theories and neglecting stellar magnetic breaking, we calculate the tidal evolution of the system and show that CoRoT-20b is presently one of the very few Darwin-stable planets that is evolving toward a triple synchronous state with equality of the orbital, planetary and stellar spin periods. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany, and Spain.

  16. Haploinsufficiency of MeCP2-interacting transcriptional co-repressor SIN3A causes mild intellectual disability by affecting the development of cortical integrity

    NARCIS (Netherlands)

    Witteveen, Josefine S.; Willemsen, Marjolein H.; Dombroski, Thais C. D.; van Bakel, Nick H. M.; Nillesen, Willy M.; van Hulten, Josephus A.; Jansen, Eric J. R.; Verkaik, Dave; Veenstra-Knol, Hermine E.; van Ravenswaaij-Arts, Conny M. A.; Wassink-Ruiter, Jolien S. Klein; Vincent, Marie; David, Albert; Le Caignec, Cedric; Schieving, Jolanda; Gilissen, Christian; Foulds, Nicola; Rump, Patrick; Strom, Tim; Cremer, Kirsten; Zink, Alexander M.; Engels, Hartmut; de Munnik, Sonja A.; Visser, Jasper E.; Brunner, Han G.; Martens, Gerard J. M.; Pfundt, Rolph; Kleefstra, Tjitske; Kolk, Sharon M.

    2016-01-01

    Numerous genes are associated with neurodevelopmental disorders such as intellectual disability and autism spectrum disorder ( ASD), but their dysfunction is often poorly characterized. Here we identified dominant mutations in the gene encoding the transcriptional repressor and MeCP2 interactor swit

  17. Haploinsufficiency of MeCP2-interacting transcriptional co-repressor SIN3A causes mild intellectual disability by affecting the development of cortical integrity

    NARCIS (Netherlands)

    Witteveen, Josefine S; Willemsen, Marjolein H; Dombroski, Thaís C D; van Bakel, Nick H M; Nillesen, Willy M; van Hulten, Josephus A; Jansen, Eric J R; Verkaik, Dave; Veenstra-Knol, Hermine E.; Ravenswaaij-Arts, van Conny; Klein Wassink-Ruiter, Jolien S.; Vincent, Marie; David, Albert; Le Caignec, Cedric; Schieving, Jolanda; Gilissen, Christian; Foulds, Nicola; Rump, Patrick; Strom, Tim; Cremer, Kirsten; Zink, Alexander M; Engels, Hartmut; de Munnik, Sonja A; Visser, Jasper E; Brunner, Han G; Martens, Gerard J M; Pfundt, Rolph; Kleefstra, Tjitske; Kolk, Sharon M

    2016-01-01

    Numerous genes are associated with neurodevelopmental disorders such as intellectual disability and autism spectrum disorder (ASD), but their dysfunction is often poorly characterized. Here we identified dominant mutations in the gene encoding the transcriptional repressor and MeCP2 interactor switc

  18. Nanocomposites Derived From a Low-Color Aromatic Polyimide (CP2) and Amine-Functionalized Vapor-Grown Carbon Nanofibers: In Situ Polymerization and Characterization (Preprint)

    Science.gov (United States)

    2007-01-01

    diffractions ( WAXS ) of compression-molded samples were recorded with a Rigaku RU-200 diffractometer using Ni-filtered Cu KR radiation (40 kV, 100 mA, λ...0.8 μm PTFE membrane and washed with large amount of THF. The filtrates containing soluble polyimides (THF-soluble CP2) were concentrated and the

  19. Loss of MeCP2 in Parvalbumin-and Somatostatin-Expressing Neurons in Mice Leads to Distinct Rett Syndrome-like Phenotypes.

    Science.gov (United States)

    Ito-Ishida, Aya; Ure, Kerstin; Chen, Hongmei; Swann, John W; Zoghbi, Huda Y

    2015-11-18

    Inhibitory neurons are critical for proper brain function, and their dysfunction is implicated in several disorders, including autism, schizophrenia, and Rett syndrome. These neurons are heterogeneous, and it is unclear which subtypes contribute to specific neurological phenotypes. We deleted Mecp2, the mouse homolog of the gene that causes Rett syndrome, from the two most populous subtypes, parvalbumin-positive (PV+) and somatostatin-positive (SOM+) neurons. Loss of MeCP2 partially impairs the affected neuron, allowing us to assess the function of each subtype without profound disruption of neuronal circuitry. We found that mice lacking MeCP2 in either PV+ or SOM+ neurons have distinct, non-overlapping neurological features: mice lacking MeCP2 in PV+ neurons developed motor, sensory, memory, and social deficits, whereas those lacking MeCP2 in SOM+ neurons exhibited seizures and stereotypies. Our findings indicate that PV+ and SOM+ neurons contribute complementary aspects of the Rett phenotype and may have modular roles in regulating specific behaviors.

  20. The transcriptional factor LBP-1c/CP2/LSF gene on chromosome 12 is a genetic determinant of Alzheimer's disease.

    Science.gov (United States)

    Lambert, J C; Goumidi, L; Vrièze, F W; Frigard, B; Harris, J M; Cummings, A; Coates, J; Pasquier, F; Cottel, D; Gaillac, M; St Clair, D; Mann, D M; Hardy, J; Lendon, C L; Amouyel, P; Chartier-Harlin, M C

    2000-09-22

    Although the varepsilon4 allele of the apolipoprotein E gene appears as an important biological marker for Alzheimer's disease (AD) susceptibility, other genetic determinants are clearly implicated in the AD process. Here, we propose that a genetic variation in the transcriptional factor LBP-1c/CP2/LSF gene, located close to the LRP locus, is a genetic susceptibility factor for AD. We report an association between a non-coding polymorphism (G-->A) in the 3'-untranslated region of this gene and sporadic AD in French and British populations and a similar trend in a North American population. The combined analysis of these three independent populations provides evidence of a protective effect of the A allele (OR = 0.58, 95% CI 0.44-0.75). We describe a potential biologically relevant role for the A allele whereby it reduces binding to nuclear protein(s). The absence of the A allele was associated with a lower LBP-1c/CP2/LSF gene expression in lymphocytes from AD cases compared with controls. Our data suggest that polymorphic variation in the implication of the LBP-1c/CP2/LSF gene may be important for the pathogenesis of AD, particularly since LBP-1c/CP2/LSF interacts with proteins such as GSKbeta, Fe65 and certain factors involved in the inflammatory response.

  1. Analysis of neonatal brain lacking ATRX or MeCP2 reveals changes in nucleosome density, CTCF binding and chromatin looping.

    Science.gov (United States)

    Kernohan, Kristin D; Vernimmen, Douglas; Gloor, Gregory B; Bérubé, Nathalie G

    2014-07-01

    ATRX and MeCP2 belong to an expanding group of chromatin-associated proteins implicated in human neurodevelopmental disorders, although their gene-regulatory activities are not fully resolved. Loss of ATRX prevents full repression of an imprinted gene network in the postnatal brain and in this study we address the mechanistic aspects of this regulation. We show that ATRX binds many imprinted domains individually but that transient co-localization between imprinted domains in the nuclei of neurons does not require ATRX. We demonstrate that MeCP2 is required for ATRX recruitment and that deficiency of either ATRX or MeCP2 causes decreased frequency of long-range chromatin interactions associated with altered nucleosome density at CTCF-binding sites and reduced CTCF occupancy. These findings indicate that MeCP2 and ATRX regulate gene expression at a subset of imprinted domains by maintaining a nucleosome configuration conducive to CTCF binding and to the maintenance of higher order chromatin structure.

  2. The Fe65 adaptor protein interacts through its PID1 domain with the transcription factor CP2/LSF/LBP1.

    Science.gov (United States)

    Zambrano, N; Minopoli, G; de Candia, P; Russo, T

    1998-08-07

    The neural protein Fe65 possesses three putative protein-protein interaction domains: one WW domain and two phosphotyrosine interaction/phosphotyrosine binding domains (PID1 and PID2); the most C-terminal of these domains (PID2) interacts in vivo with the Alzheimer's beta-amyloid precursor protein, whereas the WW domain binds to Mena, the mammalian homolog of Drosophila-enabled protein. By the interaction trap procedure, we isolated a cDNA clone encoding a possible ligand of the N-terminal PID/PTB domain of Fe65 (PID1). Sequence analysis of this clone revealed that this ligand corresponded to the previously identified transcription factor CP2/LSF/LBP1. Co-immunoprecipitation experiments demonstrated that the interaction between Fe65 and CP2/LSF/LBP1 also takes place in vivo between the native molecules. The localization of both proteins was studied using fractionated cellular extracts. These experiments demonstrated that the various isoforms of CP2/LSF/LBP1 are differently distributed among subcellular fractions. At least one isoform, derived from alternative splicing (LSF-ID), is present outside the nucleus; Fe65 was found in both fractions. Furthermore, transfection experiments with an HA-tagged CP2/LSF/LBP1 cDNA demonstrated that Fe65 interacts also with the nuclear form of CP2/LSF/LBP1. Considering that the analysis of Fe65 distribution in fractionated cell extracts demonstrated that this protein is present both in nuclear and non-nuclear fractions, we examined the expression of Fe65 deletion mutants in the two fractions. This analysis allowed us to observe that a small region N-terminal to the WW domain is phosphorylated and is necessary for the presence of Fe65 in the nuclear fraction.

  3. Potential interaction between the GARS-AIRS-GART Gene and CP2/LBP-1c/LSF transcription factor in Down syndrome-related Alzheimer disease.

    Science.gov (United States)

    Banerjee, Disha; Nandagopal, Krishnadas

    2007-12-01

    (1) GARS-AIRS-GART is an important candidate gene in studies of Down syndrome (DS)-related Alzheimer's disease (AD), due to its chromosomal localization (21q22.1) in the Down syndrome critical region, involvement in de novo purine biosynthesis, and over-expression in DS brain. The aim of this study was to identify factor(s) likely to enhance transcription of GARS-AIRS-GART in DS-related AD. (2) Based on a bio-informatics approach, the PromoterInspector, Promoter Scan II, and EBI toolbox CpG plot software programs were used to identify GARS-AIRS-GART sequences important for gene transcription. Transcription factor binding motifs within these regions were mapped with the help of the MatInspector and TFSEARCH programs. Factors implicated in neurodevelopment or neurodegeneration were the focus of attention, and mining of human (T1Dbase) and murine (GNF) expression databases revealed information on the regional distribution of these factors and their relative abundance vis-a-vis GARS-AIRS-GART. (3) The Leader-binding protein 1-c (LBP-1c/CP2/LSF) emerged as a promising candidate from these studies, as MatInspector and TFSEARCH analyses revealed a total of four CP2 binding sites with potential for functional interaction(s) within the promoter and CpG islands of GARS-AIRS-GART. Furthermore, two of these sites harbor sequences for methylation-sensitive restriction enzymes, which suggest that methylation status may, in part, regulate CP2-mediated transcription of GARS-AIRS-GART. A search of T1Dbase and GNF expression databases reveals co-expression of CP2 and GARS-AIRS-GART in brain regions relevant to DS-related AD. (4) The virtual screen identified CP2/LBP-1c/LSF as a factor that likely mediates enhanced transcription of GARS-AIRS-GART in DS-related AD.

  4. Transiting exoplanets from the CoRoT space mission. XI. CoRoT-8b: a hot and dense sub-Saturn around a K1 dwarf

    CERN Document Server

    Bordé, P; Deleuil, M; Cabrera, J; Jorda, L; Lovis, C; Csizmadia, S; Aigrain, S; Almenara, J M; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Benz, W; Bonomo, A S; Bruntt, H; Carone, L; Carpano, S; Deeg, H; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gazzano, J -C; Gillon, M; Guenther, E; Guillot, T; Guterman, P; Hatzes, A; Havel, M; Hébrard, G; Lammer, H; Léger, A; Mayor, M; Mazeh, T; Moutou, C; Pätzold, M; Pepe, F; Ollivier, M; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Santerne, A; Schneider, J; Tingley, B; Udry, S; Weingrill, J; Wuchterl, G

    2010-01-01

    We report the discovery of CoRoT-8b, a dense small Saturn-class exoplanet that orbits a K1 dwarf in 6.2 days, and we derive its orbital parameters, mass, and radius. We analyzed two complementary data sets: the photometric transit curve of CoRoT-8b as measured by CoRoT and the radial velocity curve of CoRoT-8 as measured by the HARPS spectrometer. We find that CoRoT-8b is on a circular orbit with a semi-major axis of 0.063 +/- 0.001 AU. It has a radius of 0.57 +/- 0.02 RJ, a mass of 0.22 +/- 0.03 MJ, and therefore a mean density 1.6 +/- 0.1 g/cm^3. With 67 % of the size of Saturn and 72 % of its mass, CoRoT-8b has a density comparable to that of Neptune (1.76 g/cm^3). We estimate its content in heavy elements to be 47-63 Earth masses, and the mass of its hydrogen-helium envelope to be 7-23 Earth masses. At 0.063 AU, the thermal loss of hydrogen of CoRoT-8b should be no more than about 0.1 % over an assumed integrated lifetime of 3~Ga.

  5. Revisiting the transits of CoRoT-7b at a lower activity level

    CERN Document Server

    Barros, S C C; Deleuil, M; Diaz, R F; Csizmadia, Sz; Cabrera, J; Chaintreuil, S; Cameron, A Collier; Hatzes, A; Haywood, R; Lanza, A F; Aigrain, S; Alonso, R; Bordé, R; Bouchy, F; Deeg, H J; Erikson, A; Fridlund, M; Grziwa, S; Gandolfi, D; Guillot, T; Guenther, E; Leger, A; Moutou, C; Ollivier, M; Pasternacki, T; Patzold, M; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Wuchterl, G

    2014-01-01

    CoRoT-7b, the first super-Earth with measured radius discovered, has opened the new field of rocky exoplanets characterisation. To better understand this interesting system, new observations were taken with the CoRoT satellite. During this run 90 new transits were obtained in the imagette mode. These were analysed together with the previous 151 transits obtained in the discovery run and HARPS radial velocity observations to derive accurate system parameters. A difference is found in the posterior probability distribution of the transit parameters between the previous CoRoT run (LRa01) and the new run (LRa06). We propose this is due to an extra noise component in the previous CoRoT run suspected to be transit spot occultation events. These lead to the mean transit shape becoming V-shaped. We show that the extra noise component is dominant at low stellar flux levels and reject these transits in the final analysis. We obtained a planetary radius, $R_p= 1.585\\pm0.064\\,R_{\\oplus}$, in agreement with previous estim...

  6. Corotation torques experienced by planets embedded in weakly magnetized turbulent discs

    CERN Document Server

    Baruteau, C; Nelson, R P; Masset, F

    2011-01-01

    The migration of low-mass planets is driven by the differential Lindblad torque and the corotation torque in non-magnetic viscous models of protoplanetary discs. The corotation torque has recently received detailed attention as it may slow down, stall, or reverse migration. In laminar viscous disc models, the long-term evolution of the corotation torque is intimately related to viscous and thermal diffusion processes in the planet's horseshoe region. This paper examines the properties of the corotation torque in discs where MHD turbulence develops as a result of the magnetorotational instability, considering a weak initial toroidal magnetic field. We present results of 3D MHD simulations carried out with two different codes. Non-ideal MHD effects and the disc's vertical stratification are neglected, and locally isothermal disc models are considered. The running time-averaged torque exerted by the disc on a fixed planet is evaluated in three disc models. We first present results with an inner disc cavity (plan...

  7. Spectral characterization and differential rotation study of active CoRoT stars

    CERN Document Server

    Nagel, Evangelos; Schmitt, Jürgen H M M

    2016-01-01

    The CoRoT space telescope observed nearly 160 000 light curves. Among the most outstanding is that of the young, active planet host star CoRoT-2A. In addition to deep planetary transits, the light curve of CoRoT-2A shows strong rotational variability and a superimposed beating pattern. To study the stars that produce such an intriguing pattern of photometric variability, we identified a sample of eight stars with rotation periods between 0.8 and 11 days and photometric variability amplitudes of up to 7.5 %, showing a similar CoRoT light curve. We also obtained high-resolution follow-up spectroscopy with TNG/SARG and carried out a spectral analysis with SME and MOOG. We find that the color dependence of the light curves is consistent with rotational modulation due to starspots and that latitudinal differential rotation provides a viable explanation for the light curves, although starspot evolution is also expected to play an important role. Our MOOG and SME spectral analyses provide consistent results, showing...

  8. Mixed modes in red-giant stars observed with CoRoT

    NARCIS (Netherlands)

    Mosser, B.; Barban, C.; Montalban, J.; Beck, P.G.; Miglio, A.; Belkacem, K.; Goupil, M.J.; Hekker, S.; de Ridder, J.; Dupret, M.A.; Elsworth, Y.; Noels, A.; Baudin, F.; Michel, A.E.; Samadi, R.; Auvergne, M.; Baglin, A.; Catala, C.

    2011-01-01

    Context. The CoRoT mission has provided thousands of red-giant light curves. The analysis of their solar-like oscillations allows us to characterize their stellar properties. Aims. Up to now, the global seismic parameters of the pressure modes have been unable to distinguish red-clump giants from

  9. Stellar hydrodynamics caught in the act: Asteroseismology with CoRoT and Kepler

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jørgen; Thompson, Michael J.

    2011-01-01

    Asteroseismic investigations, particularly based on data on stellar oscillations from the CoRoT and Kepler space missions, are providing unique possibilities for investigating the properties of stellar interiors. This constitutes entirely new ways to study the effects of dynamic phenomena on stel...... obtained from such investigations, across the Hertzsprung-Russell diagram....

  10. On the Stability of a Magnetized Disk with a Massive Corotating Halo

    Institute of Scientific and Technical Information of China (English)

    CHOU Chih-Kang; PENG Qiu-He

    2001-01-01

    The effects of magnetic fields on the stability of a differentially rotating disk are considered in the shearing sheetapproximation. An explicit stability criterion is derived in terms of Toomre's Q value and the field strength. Thecombined effects of both magnetic fields and a corotating dark matter halo are briefly discussed.

  11. Bright optical dayside emission from extrasolar planet CoRoT-2b

    CERN Document Server

    Snellen, I A G; Burrows, A

    2009-01-01

    We present our analysis of the red-channel CoRoT data of extrasolar planet CoRoT-2b. A deep secondary eclipse is detected at a level of 1.02+-0.20x10^-4, which suggests that all of the planet-signal detected previously in white light by Alonso et al. (2009) originates from the red channel. CoRoT-2b is the coolest exoplanet that has been detected in the optical so far. In contrast to the other planets, its measured brightness temperature of 2170+-50 K is significantly higher than its maximum hemisphere-averaged effective day-side temperature. However, it is not expected that a hot Jupiter radiates as a black body, and its thermal spectrum can deviate significantly from a Planck curve. We present models of the planet/star flux ratio as function of wavelength, which are calculated for a T/P profile in radiative and hydrostatic equilibrium, using a self-consistent atmosphere code. These are compared with the CoRoT detection. We estimate that reflected light contributes only at a 10-20% level to the total optical ...

  12. Pattern Corotation Radii from Potential-Density Phase-Shifts for 153 OSUBGS Sample Galaxies

    CERN Document Server

    Buta, Ronald J

    2009-01-01

    We apply the potential-density phase-shift method to 153 galaxies in the Ohio State University Bright Galaxy Survey (OSUBGS) to study the general relationship between pattern corotation radii and the morphology of spiral galaxies. The analysis is based on deprojected near-infrared H-band images. We find that multiple pattern speeds are common in disk galaxies. By selecting those corotation radii close to or slightly larger than the bar radius as being the bar corotation (CR) radius, we find that the average and standard deviation of the ratio R = r(CR)/r(bar), is 1.20+/-0.52 for 101 galaxies having well-defined bars. There is an indication that this ratio depends weakly on galaxy type in the sense that the average ranges from 1.03+/-0.37 for 65 galaxies of type Sbc and earlier, to 1.50+/-0.63 for 36 galaxies of type Sc and later. Our bar corotation radii are on average smaller than those estimated from single-pattern-speed numerical simulations, most likely because these simulations tend to find the pattern s...

  13. The LAEX and NASA portals for CoRoT public data

    CERN Document Server

    Solano, E; Velasco, A; Ciardi, D R; Gutíerrez, R; McElroy, D L; López, M; Abajian, M; García, M; Ali, B; Sarro, L M; Berriman, G B; Bryden, G; Chan, B; Good, J; Kane, S R; Laity, A C; Lau, C; Payne, A N; Plavchan, P; Ramírez, S; Schmitz, M; Stauffer, J R; Wyatt, P L; Zhang, A

    2009-01-01

    * Aims. We describe here the main functionalities of the LAEX (Laboratorio de Astrofisica Estelar y Exoplanetas/Laboratory for Stellar Astrophysics and Exoplanets) and NASA portals for CoRoT Public Data. The CoRoT archive at LAEX was opened to the community in January 2009 and is managed in the framework of the Spanish Virtual Observatory. NStED (NASA Star and Exoplanet Database) serves as the CoRoT portal for the US astronomical community. NStED is a general purpose stellar and exoplanet archive with the aim of providing support for NASA planet finding and characterisation goals, and the planning and support of NASA and other space missions. CoRoT data at LAEX and NStED can be accessed at http://sdc.laeff.inta.es/corotfa/ and http://nsted.ipac.caltech.edu,respectively. * Methods. Based on considerable experience with astronomical archives, the aforementioned archives are designed with the aim of delivering science-quality data in a simple and efficient way. * Results. LAEX and NStED not only provide access t...

  14. Modeling heat efficiency, flow and scale-up in the corotating disc scraped surface heat exchanger

    DEFF Research Database (Denmark)

    Friis, Alan; Szabo, Peter; Karlson, Torben

    2002-01-01

    A comparison of two different scale corotating disc scraped surface heat exchangers (CDHE) was performed experimentally. The findings were compared to predictions from a finite element model. We find that the model predicts well the flow pattern of the two CDHE's investigated. The heat transfer...

  15. Accretion dynamics and disk evolution in NGC 2264: a study based on the Corot photometric observations

    CERN Document Server

    Alencar, S H P; Guimaraes, M M; McGinnis, P T; Gameiro, J F; Bouvier, J; Aigrain, S; Flaccomio, E; Favata, F

    2010-01-01

    The young cluster NGC 2264 was observed with the Corot satellite for 23 days uninterruptedly in March 2008 with unprecedent photometric accuracy. We present here the first results of the analysis of the accreting population. We intended to look for possible light curve variability of the same nature as that observed in the classical T Tauri star AA Tau, which was attributed to a magnetically controlled inner disk warp, which is directly associated with the interaction between the stellar magnetic field and the inner disk region. We analysed the Corot light curves of 83 previously known classical T Tauri stars that belong to NGC 2264 and classified them according to their morphology. We also studied the Corot light curve morphology as a function of a Spitzer-based classification of the star-disk systems. The classification derived on the basis of the Corot light curve morphology agrees very well with the Spitzer IRAC-based classification of the systems. The percentage of AA Tau-like light curves decreases as t...

  16. Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system

    CERN Document Server

    Haywood, R D; Queloz, D; Barros, S C C; Deleuil, M; Fares, R; Gillon, M; Lanza, A F; Lovis, C; Moutou, C; Pepe, F; Pollacco, D; Santerne, A; Segransan, D; Unruh, Y C

    2014-01-01

    Since the discovery of the transiting super-Earth CoRoT-7b, several investigations have yielded different results for the number and masses of planets present in the system, mainly owing to the star's high level of activity. We re-observed CoRoT-7 in January 2012 with both HARPS and CoRoT, so that we now have the benefit of simultaneous radial-velocity and photometric data. This allows us to use the off-transit variations in the star's light curve to estimate the radial-velocity variations induced by the suppression of convective blueshift and the flux blocked by starspots. To account for activity-related effects in the radial-velocities which do not have a photometric signature, we also include an additional activity term in the radial-velocity model, which we treat as a Gaussian process with the same covariance properties (and hence the same frequency structure) as the light curve. Our model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b a...

  17. Planetary transit candidates in the CoRoT LRa01 field

    CERN Document Server

    Carone, L; Cabrera, J; Hatzes, A P; Deeg, H J; Csizmadia, Sz; Paetzold, M; Weingrill, J; Aigrain, S; Alonso, R; Alapini, A; Almenara, J -M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Bruntt, H; Carpano, S; Cochran, W D; Deleuil, M; Díaz, R F; Dreizler, S; Dvorak, R; Eisloeffel, J; Eigmueller, P; Endl, M; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gazzano, J -C; Gibson, N; Gillon, M; Gondoin, P; Grziwa, S; Guenther, E W; Guillot, T; Hartmann, M; Havel, M; Hébrard, G; Jorda, L; Kabath, P; Léger, A; Llebaria, A; Lammer, H; Lovis, C; MacQueen, P J; Mayor, M; Mazeh, T; Moutou, C; Nortmann, L; Ofir, A; Ollivier, M; Parviainen, H; Pepe, F; Pont, F; Queloz, D; Rabus, M; Rauer, H; Régulo, C; Renner, S; de la Reza, R; Rouan, D; Santerne, A; Samuel, B; Schneider, J; Shporer, A; Stecklum, B; Tal-Or, L; Tingley, B; Udry, S; Wuchterl, G

    2011-01-01

    Context: CoRoT is a pioneering space mission whose primary goals are stellar seismology and extrasolar planets search. Its surveys of large stellar fields generate numerous planetary candidates whose lightcurves have transit-like features. An extensive analytical and observational follow-up effort is undertaken to classify these candidates. Aims: The list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation towards the Galactic anti-center is presented. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. Methods: 7470 chromatic and 3938 monochromatic lightcurves were acquired and analysed. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves. Results: Fifty-one stars were classified as planetary transit candidates in LRa01. Thirty-seven (i.e., 73 % of all candidates) are "good" planetary candidates ba...

  18. Flow characteristics of screws and special mixing enhancers in a co-rotating twin screw extruder

    NARCIS (Netherlands)

    Brouwer, T.; Todd, D.B.; Janssen, L.P.B.M.

    2002-01-01

    The flow behavior of a Newtonian fluid through special mixing enhancers in a modular intermeshing co-rotating twin screw extruder has been examined. The mixing enhancers are slotted screws and gear mixing elements. Particular attention has been directed to drag and pressure flow characteristics and

  19. Differential regulation of MeCP2 and PP1 in passive or voluntary administration of cocaine or food.

    Science.gov (United States)

    Bodetto, Sarah Pol; Romieu, Pascal; Sartori, Maxime; Tesone-Coelho, Carolina; Majchrzak, Monique; Barbelivien, Alexandra; Zwiller, Jean; Anglard, Patrick

    2014-12-01

    Cocaine exposure induces changes in the expression of numerous genes, in part through epigenetic modifications. We have initially shown that cocaine increases the expression of the chromatin remodeling protein methyl-CpG binding protein 2 (MeCP2) and characterized the protein phosphatase-1Cβ (PP1Cβ) gene, as repressed by passive i.p. cocaine injections through a Mecp2-mediated mechanism involving de novo DNA methylation. Both proteins being involved in learning and memory processes, we investigated whether voluntary cocaine administration would similarly affect their expression using an operant self-administration paradigm. Passive and voluntary i.v. cocaine intake was found to induce Mecp2 and to repress PP1Cβ in the prefrontal cortex and the caudate putamen. This observation is consistent with the role of Mecp2 acting as a transcriptional repressor of PP1Cβ and shows that passive intake was sufficient to alter their expression. Surprisingly, striking differences were observed under the same conditions in food-restricted rats tested for food pellet delivery. In the prefrontal cortex and throughout the striatum, both proteins were induced by food operant conditioning, but remained unaffected by passive food delivery. Although cocaine and food activate a common reward circuit, changes observed in the expression of other genes such as reelin and GAD67 provide new insights into molecular mechanisms differentiating neuroadaptations triggered by each reinforcer. The identification of hitherto unknown genes differentially regulated by drugs of abuse and a natural reinforcer should improve our understanding of how two rewarding stimuli differ in their ability to drive behavior.

  20. On the role of corotation radius in the low T/W dynamical instability of differentially rotating stars

    Science.gov (United States)

    Yoshida, Shin'ichirou; Saijo, Motoyuki

    2017-04-01

    We investigate the nature of so-called low T/W dynamical instability in a differentially rotating star, by focusing on the role played by the corotation radius of the unstable oscillation modes. A one-dimensional model of linear perturbation, which neglects dependence of variables on the coordinate along the rotational axis of the star, is solved to obtain stable and unstable eigenmodes. A linear eigenmode having a corotation radius, at which azimuthal pattern speed of the mode coincides with the stellar angular velocity, is categorized to either a complex (growing or damping) mode or a purely real mode belonging to a continuous spectrum of frequency. We compute canonical angular momentum and its flux to study eigenmodes with corotation radius. In a dynamically unstable mode, sound wave transports its angular momentum in such a way that the absolute value of the angular momentum is increased on both sides of the corotation radius. We further evaluate growth of amplitude of reflected sound wave incident to a corotation point, and find that the overreflection of the wave and the trapping of it between the corotation radius and the surface of the star may qualitatively explain dependences of eigenfrequencies on the stellar differential rotation. The results suggest that the low T/W instability may be caused by overreflection of sound waves trapped mainly between the surface of the star and a corotation radius.

  1. Secondary eclipses in the CoRoT light curves: A homogeneous search based on Bayesian model selection

    CERN Document Server

    Parviainen, Hannu; Belmonte, Juan Antonio

    2012-01-01

    We aim to identify and characterize secondary eclipses in the original light curves of all published CoRoT planets using uniform detection and evaluation critetia. Our analysis is based on a Bayesian model selection between two competing models: one with and one without an eclipse signal. The search is carried out by mapping the Bayes factor in favor of the eclipse model as a function of the eclipse center time, after which the characterization of plausible eclipse candidates is done by estimating the posterior distributions of the eclipse model parameters using Markov Chain Monte Carlo. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b. The previously published CoRoT-1b and CoRoT-2b eclipses are also confirmed.

  2. TARGET:?

    National Research Council Canada - National Science Library

    James M Acton

    2014-01-01

      By 2003. as military planners had become worried that the country's long-range conventional weapons, such as cruise missiles, might be too slow to reach hypothetical distant targets that needed to be struck urgently...

  3. Functional Analysis of CP2-Like Domain and SAM-Like Domain in TFCP2L1, Novel Pluripotency Factor of Embryonic Stem Cells.

    Science.gov (United States)

    Kim, Chang Min; Jang, Tae-Ho; Park, Hyun Ho

    2016-06-01

    TFCP2L1 is a transcription factor that facilitates establishment and maintenance of pluripotency in embryonic stem cells by forming a complex transcriptional network with other transcription factors (OCT4, SOX2, and NANOG). TFCP2L1 contains two distinct domains, the CP2-like domain at the N-terminus and the SAM-like domain at the C-terminus. In this study, we found that TFCP2L1 is hexamerized in solution via the C-terminal SAM-like domain. We also found that homo-oligomerization of SAM-like domain is dependent on the concentration of the proteins. Finally, we found that TFCP2L1 binds directly to DNA via the N-terminal CP2-like domain.

  4. Transiting exoplanets from the CoRoT space mission: XIII. CoRoT-14b: an unusually dense very hot Jupiter

    CERN Document Server

    Tingley, B; Gazzano, J -C; Alonso, R; Mazeh, T; Jorda, L; Aigrain, S; Almenara, J -M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Carpano, S; Carone, L; Cochran, W D; Csizmadia, Sz; Deleuil, M; Deeg, H J; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gillon, M; Guenther, E W; Guillot, T; Hatzes, A; Hébrard, G; Léger, A; Llebaria, A; Lammer, H; Lovis, C; MacQueen, P J; Moutou, C; Ollivier, M; Ofir, A; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Shporer, A; Wuchterl, G

    2011-01-01

    In this paper, the CoRoT Exoplanet Science Team announces its 14th discovery. Herein, we discuss the observations and analyses that allowed us to derive the parameters of this system: a hot Jupiter with a mass of $7.6 \\pm 0.6$ Jupiter masses orbiting a solar-type star (F9V) with a period of only 1.5 d, less than 5 stellar radii from its parent star. It is unusual for such a massive planet to have such a small orbit: only one other known exoplanet with a higher mass orbits with a shorter period.

  5. The fold recognition of CP2 transcription factors gives new insights into the function and evolution of tumor suppressor protein p53.

    Science.gov (United States)

    Kokoszynska, Katarzyna; Ostrowski, Jerzy; Rychlewski, Leszek; Wyrwicz, Lucjan S

    2008-09-15

    The CP2 transcription factor (TFCP2) is a critical regulator of erythroid gene expression. Apart from the involvement in the transcriptional switch of globin gene promoters it activates an array of cellular and viral gene promoters. A number of homologous proteins was identified in genomes of Metazoa, with additional five homologues encoded by the human genome (TFCP2L1, UBP1, GRHL1, GRHL2, GRHL3). Although several experimental studies have already been published, the knowledge on the molecular mechanism of activity of this transcription factors remains very limited. Here we present the application of fold recognition and protein structure prediction in drafting the structure-to-function relationship of the CP2 family. The employed procedure clearly shows that the family adopts a DNA binding immunoglobulin fold homologous to the p53 (TP53) core domain, and a novel type of ubiquitin-like domain and a sterile alpha motif (SAM) form oligomerization modules. With a traceable evolution of CP2 family throughout the Metazoa group this protein family is highly likely to represent an ancestor of the critical cell cycle regulator p53. Based on this observation several functional hypotheses on structure-to-function relationship of p53 were drawn. The DNA motif recognized by p53 is a result of further specialization of the CP2 DNA-binding module. The analysis also shows the critical role of protein oligomerization for the function of this protein superfamily. Finally, the identification of distant homologs of TP53 allowed performing a phylogenetic footprinting analysis explaining the role of the specific amino acids important for both - the protein folding and the binding of DNA.

  6. Altered chromatin structure associated with methylation-induced gene silencing in cancer cells: correlation of accessibility, methylation, MeCP2 binding and acetylation

    Science.gov (United States)

    Nguyen, Carvell T.; Gonzales, Felicidad A.; Jones, Peter A.

    2001-01-01

    Silencing of tumor-suppressor genes by hypermethylation of promoter CpG islands is well documented in human cancer and may be mediated by methyl-CpG-binding proteins, like MeCP2, that are associated in vivo with chromatin modifiers and transcriptional repressors. However, the exact dynamic between methylation and chromatin structure in the regulation of gene expression is not well understood. In this study, we have analyzed the methylation status and chromatin structure of three CpG islands in the p14(ARF)/p16(INK4A) locus in a series of normal and cancer cell lines using methylation-sensitive digestion, MspI accessibility in intact nuclei and chromatin immunoprecipitation (ChIP) assays. We demonstrate the existence of an altered chromatin structure associated with the silencing of tumor-suppressor genes in human cancer cell lines involving CpG island methylation, chromatin condensation, histone deacetylation and MeCP2 binding. The data showed that MeCP2 could bind to methylated CpG islands in both promoters and exons; MeCP2 does not interfere with transcription when bound at an exon, suggesting a more generalized role for the protein beyond transcriptional repression. In the absence of methylation, it is demonstrated that CpG islands located in promoters versus exons display marked differences in the levels of acetylation of associated histone H3, suggesting that chromatin remodeling can be achieved by methylation-independent processes and perhaps explaining why non-promoter CpG islands are more susceptible to de novo methylation than promoter islands. PMID:11713309

  7. Abnormalities of cell packing density and dendritic complexity in the MeCP2 A140V mouse model of Rett syndrome/X-linked mental retardation

    Directory of Open Access Journals (Sweden)

    Blue Mary

    2010-02-01

    Full Text Available Abstract Background Rett syndrome (RTT, a common cause of mental retardation in girls, is associated with mutations in the MECP2 gene. Most human cases of MECP2 mutation in girls result in classical or variant forms of RTT. When these same mutations occur in males, they often present as severe neonatal encephalopathy. However, some MECP2 mutations can also lead to diseases characterized as mental retardation syndromes, particularly in boys. One of these mutations, A140V, is a common, recurring missense mutation accounting for about 0.6% of all MeCP2 mutations and ranking 21st by frequency. It has been described in familial X-linked mental retardation (XLMR, PPM- X syndrome (Parkinsonism, Pyramidal signs, Macroorchidism, X-linked mental retardation and in other neuropsychiatric syndromes. Interestingly, this mutation has been reported to preserve the methyl-CpG binding function of the MeCP2 protein while compromising its ability to bind to the mental retardation associated protein ATRX. Results We report the construction and initial characterization of a mouse model expressing the A140V MeCP2 mutation. These initial descriptive studies in male hemizygous mice have revealed brain abnormalities seen in both RTT and mental retardation. The abnormalities found include increases in cell packing density in the brain and a significant reduction in the complexity of neuronal dendritic branching. In contrast to some MeCP2 mutation mouse models, the A140V mouse has an apparently normal lifespan and normal weight gain patterns with no obvious seizures, tremors, breathing difficulties or kyphosis. Conclusion We have identified various neurological abnormalities in this mouse model of Rett syndrome/X-linked mental retardation which may help to elucidate the manner in which MECP2 mutations cause neuronal changes resulting in mental retardation without the confounding effects of seizures, chronic hypoventilation, or other Rett syndrome associated symptoms.

  8. Intracellular domains of amyloid precursor-like protein 2 interact with CP2 transcription factor in the nucleus and induce glycogen synthase kinase-3beta expression.

    Science.gov (United States)

    Xu, Y; Kim, H-S; Joo, Y; Choi, Y; Chang, K-A; Park, C H; Shin, K-Y; Kim, S; Cheon, Y-H; Baik, T-K; Kim, J-H; Suh, Y-H

    2007-01-01

    Amyloid precursor protein (APP) is a member of a gene family that includes two APP-like proteins, APLP1 and 2. Recently, it has been reported that APLP1 and 2 undergo presenilin-dependent gamma-secretase cleavage, as does APP, resulting in the release of an approximately 6 kDa intracellular C-terminal domain (ICD), which can translocate into the nucleus. In this study, we demonstrate that the APLP2-ICDs interact with CP2/LSF/LBP1 (CP2) transcription factor in the nucleus and induce the expression of glycogen synthase kinase 3beta (GSK-3beta), which has broad-ranged substrates such as tau- and beta-catenin. The significance of this finding is substantiated by the in vivo evidence of the increase in the immunoreactivities for the nuclear C-terminal fragments of APLP2, and for GSK-3beta in the AD patients' brain. Taken together, these results suggest that APLP2-ICDs contribute to the AD pathogenesis, by inducing GSK-3beta expression through the interaction with CP2 transcription factor in the nucleus.

  9. Association of the 3' UTR transcription factor LBP-1c/CP2/LSF polymorphism with late-onset Alzheimer's disease.

    Science.gov (United States)

    Luedecking-Zimmer, Erin; DeKosky, Steven T; Nebes, Robert; Kamboh, M Ilyas

    2003-02-01

    Alzheimer's disease (AD) is a genetically heterogeneous neurodegenerative disorder. To date, apolipoprotein E (apoE) is the only established susceptibility gene for late-onset AD. ApoE accounts for less than 50% of the risk of AD, indicating the presence of other unknown susceptibility loci. Linkage studies have indicated chromosome 12 as the most likely location for another late-onset AD locus. We examined seven polymorphisms in five candidate genes located in and around the linkage peaks on chromosome 12 in 564 cases and 523 controls. The genes included complement component 1R (C1R), vitamin D receptor (VDR), scavenger-receptor B1 (SR-B1), low-density lipoprotein receptor related protein 1 (LRP1), and transcription factor LBP-1c/CP2/LSF. We found no association with C1R, VDR, SR-B1, and LRP1 polymorphisms. However, the frequency of the A allele of the 3' (untranslated region) UTR LBP-1c/CP2/LSF polymorphism was higher in controls than cases (0.071 vs. 0.051; P = 0.042) with an adjusted odds ratio (OR) of 0.65 (95% confidence interval [CI]: 0.43-0.96; P = 0.0498). Our data suggest that the LBP-1c/CP2/LSF polymorphism may have a moderate protective effect against the risk of AD.

  10. Application of the Hubbard model to Cp*(2)Yb(bipy), a model system for strong exchange coupling in lanthanide systems.

    Science.gov (United States)

    Lukens, Wayne W; Magnani, Nicola; Booth, Corwin H

    2012-10-01

    Exchange coupling is quantified in lanthanide (Ln) single-molecule magnets (SMMs) containing a bridging N(2)(3-) radical ligand and between [Cp*(2)Yb](+) and bipy(•-) in Cp*(2)Yb(bipy), where Cp* is pentamethylcyclopentadienyl and bipy is 2,2'-bipyridyl. In the case of these lanthanide SMMs, the magnitude of exchange coupling between the Ln ion and the bridging N(2)(3-), 2J, is very similar to the barrier to magnetic relaxation, U(eff). A molecular version of the Hubbard model is applied to systems in which unpaired electrons on magnetic metal ions have direct overlap with unpaired electrons residing on ligands. The Hubbard model explicitly addresses electron correlation, which is essential for understanding the magnetic behavior of these complexes. This model is applied quantitatively to Cp*(2)Yb(bipy) to explain its very strong exchange coupling, 2J = -0.11 eV (-920 cm(-1)). The model is also used to explain the presence of strong exchange coupling in Ln SMMs in which the lanthanide spins are coupled via bridging N(2)(3-) radical ligands. The results suggest that increasing the magnetic coupling in lanthanide clusters could lead to an increase in the blocking temperatures of exchange-coupled lanthanide SMMs, suggesting routes to rational design of future lanthanide SMMs.

  11. Numerical Relativity for Inspiraling Binaries in Co-Rotating Coordinates: Test Bed for Lapse and Shift Equations

    OpenAIRE

    Thorne, Kip S.

    1998-01-01

    Gravitational-wave data analysis requires a detailed understanding of the highly relativistic, late stages of inspiral of neutron-star and black-hole binaries. A promising method to compute the late inspiral and its emitted waves is numerical relativity in co-rotating coordinates. The coordinates must be kept co-rotating via an appropriate choice of numerical relativity's lapse and shift functions. This article proposes a model problem for testing the ability of various lapse and shift prescr...

  12. Comparing gravitational waves from nonprecessing and precessing black hole binaries in the corotating frame

    CERN Document Server

    Pekowsky, Larne; Healy, Jim; Shoemaker, Deirdre

    2013-01-01

    Previous analytic and numerical calculations suggest that, at each instant, the emission from a precessing black hole binary closely resembles the emission from a nonprecessing analog. In this paper we quantitatively explore the validity and limitations of that correspondence, extracting the radiation from a large collection of roughly two hundred generic black hole binary merger simulations both in the simulation frame and in a corotating frame that tracks precession. To a first approximation, the corotating-frame waveforms resemble nonprecessing analogs, based on similarity over a band-limited frequency interval defined using a fiducial detector (here, advanced LIGO) and the source's total mass $M$. By restricting attention to masses $M\\in 200, 2500 M_\\odot$, we insure our comparisons are sensitive only to our simulated late-time inspiral, merger, and ringdown signals. In this mass region, every one of our precessing simulations can be fit by some physically similar member of the \\texttt{IMRPhenomB} phenome...

  13. Exposure-based Algorithm for Removing Systematics out of the CoRoT Light Curves

    CERN Document Server

    Guterman, P; Faigler, S

    2015-01-01

    The CoRoT space mission was operating for almost 6 years, producing thousands of continuous photometric light curves. The temporal series of exposures are processed by the production pipeline, correcting the data for known instrumental effects. But even after these model-based corrections, some collective trends are still visible in the light curves. We propose here a simple exposure-based algorithm to remove instrumental effects. The effect of each exposure is a function of only two instrumental stellar parameters, position on the CCD and photometric aperture. The effect is not a function of the stellar flux, and therefore much more robust. As an example, we show that the $\\sim2\\%$ long-term variation of the early run LRc01 is nicely detrended on average. This systematics removal process is part of the CoRoT legacy data pipeline.

  14. CoRoT observations of O stars: diverse origins of variability

    CERN Document Server

    Blomme, R; Degroote, P; Mahy, L; Aerts, C; Cuypers, J; Godart, M; Gosset, E; Hareter, M; Montalban, J; Morel, T; Nieva, M F; Noels, A; Oreiro, R; Poretti, E; Przybilla, N; Rainer, M; Rauw, G; Schiller, F; Simon-Diaz, S; Smolders, K; Ventura, P; Vuckovic, M; Auvergne, M; Baglin, A; Baudin, F; Catala, C; Michel, E; Samadi, R

    2011-01-01

    Six O-type stars were observed continuously by the CoRoT satellite during a 34.3-day run. The unprecedented quality of the data allows us to detect even low-amplitude stellar pulsations in some of these stars (HD 46202 and the binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes and solar-like stochastic oscillations, both of importance to the asteroseismological modelling of O stars. Additional effects can be seen in the CoRoT light curves, such as binarity and rotational modulation. Some of the hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the presence of red-noise: we speculate that this is related to a sub-surface convection zone.

  15. VLT transit and occultation photometry for the bloated planet CoRoT-1b

    CERN Document Server

    Gillon, M; Triaud, A H M J; Barman, T; Hebb, L; Montalban, J; Maxted, P F L; Queloz, D; Deleuil, M; Magain, P

    2009-01-01

    We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and 1.45 (+0.07,-0.13) R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09 microns (0.278 (+0.043,-0.066) %) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet.

  16. Interacting galaxies: corotating and counter-rotating systems with tidal tails

    Science.gov (United States)

    Mesa, Valeria; Duplancic, Fernanda; Alonso, Sol; Coldwell, Georgina; Lambas, Diego G.

    2014-02-01

    We analyse interacting galaxy pairs with evidence of tidal features in the Sloan Digital Sky Survey Data Release 7. The pairs were selected within z visual inspection pairs of spirals into corotating and counter-rotating systems. For a subsample of non-active galactic nucleus (non-AGN) galaxies, counter-rotating pairs have larger star formation rates and a higher fraction of young, star-forming galaxies. These effects are enhanced by restricting to rp Composite and Ambiguous AGN are similar. Also, counter-rotating hosts have more powerful AGN as revealed by enhanced Lum[O III] values. The number of corotating systems is approximately twice the number of counter-rotating pairs which could be owed to a more rapid evolution of counter-rotating systems, besides possible different initial conditions of these interacting pairs.

  17. The SARS algorithm: detrending CoRoT light curves with Sysrem using simultaneous external parameters

    CERN Document Server

    Ofir, Aviv; Bonomo, Aldo Stefano; Carone, Ludmila; Carpano, Stefania; Samuel, Benjamin; Weingrill, Jorg; Aigrain, Suzanne; Auvergne, Michel; Baglin, Annie; Barge, Pierre; Borde, Pascal; Bouchy, Francois; Deeg, Hans J; Deleuil, Magali; Dvorak, Rudolf; Erikson, Anders; Mello, Sylvio Ferraz; Fridlund, Malcolm; Gillon, Michel; Guillot, Tristan; Hatzes, Artie; Jorda, Laurent; Lammer, Helmut; Leger, Alain; Llebaria, Antoine; Moutou, Claire; Ollivier, Marc; Paetzold, Martin; Queloz, Didier; Rauer, Heike; Rouan, Daniel; Schneider, Jean; Wuchterl, Guenther

    2010-01-01

    Surveys for exoplanetary transits are usually limited not by photon noise but rather by the amount of red noise in their data. In particular, although the CoRoT spacebased survey data are being carefully scrutinized, significant new sources of systematic noises are still being discovered. Recently, a magnitude-dependant systematic effect was discovered in the CoRoT data by Mazeh & Guterman et al. and a phenomenological correction was proposed. Here we tie the observed effect a particular type of effect, and in the process generalize the popular Sysrem algorithm to include external parameters in a simultaneous solution with the unknown effects. We show that a post-processing scheme based on this algorithm performs well and indeed allows for the detection of new transit-like signals that were not previously detected.

  18. The Roles of Tidal Evolution and Evaporative Mass Loss in the Origin of CoRoT-7 b

    CERN Document Server

    Jackson, Brian; Barnes, Rory; Raymond, Sean N; Fortney, Jonathan; Greenberg, Richard

    2010-01-01

    CoRoT-7 b is the first confirmed rocky exoplanet, but, with an orbital semi-major axis of 0.0172 AU, its origins may be unlike any rocky planet in our solar system. In this study, we consider the roles of tidal evolution and evaporative mass loss in CoRoT-7 b's history, which together have modified the planet's mass and orbit. If CoRoT-7 b has always been a rocky body, evaporation may have driven off almost half its original mass, but the mass loss may depend sensitively on the extent of tidal decay of its orbit. As tides caused CoRoT-7 b's orbit to decay, they brought the planet closer to its host star, thereby enhancing the mass loss rate. Such a large mass loss also suggests the possibility that CoRoT-7 b began as a gas giant planet and had its original atmosphere completely evaporated. In this case, we find that CoRoT-7 b's original mass probably didn't exceed 200 Earth masses (about 2/3 of a Jupiter mass). Tides raised on the host star by the planet may have significantly reduced the orbital semi-major a...

  19. Co-rotational Oldroyd Fluid B Model for Spinning Flow of Liquid Crystalline Polymer

    Institute of Scientific and Technical Information of China (English)

    付强

    2003-01-01

    The relationship between the extensional viscosity and material parameters was studied through the analytical formulas of stress and extensional viscosity. The differential equations were solved to obtain the relationship between extensional viscosity and strain rates. The results obtained qualitatively agree with the experimental results. The study makes it practicable to simulate the rheologic behaviors of spinning flow of liquid crystalline polymer using co-rotational Oldroyd fluid B model.

  20. A rotating Michelson interferometer from the co-rotating point of view

    Science.gov (United States)

    Maraner, Paolo

    2016-06-01

    The phase shift induced by a uniform rotation in a Michelson interferometer is re-derived in the geometrical framework of the coordinate-free formalism of general relativity from the co-rotating point of view. The effect is second order in the ratio of the interferometer's speed to the speed of light and further suppressed by the ratio of the length of the interferometer's arms to the radius of rotation. The relation of the effect to gravitational time dilation is discussed.

  1. The potential role of NGC 205 in generating Andromeda's vast thin corotating plane of satellite galaxies

    Science.gov (United States)

    Angus, Garry W.; Coppin, Paul; Gentile, Gianfranco; Diaferio, Antonaldo

    2016-11-01

    The Andromeda galaxy is observed to have a system of two large dwarf ellipticals and ˜13 smaller satellite galaxies that are currently corotating in a thin plane, in addition to 2 counter-rotating satellite galaxies. We explored the consistency of those observations with a scenario where the majority of the corotating satellite galaxies originated from a subhalo group, where NGC 205 was the host and the satellite galaxies occupied dark matter sub-subhaloes. We ran N-body simulations of a close encounter between NGC 205 and M31. In the simulations, NGC 205 was surrounded by massless particles to statistically sample the distribution of the sub-subhaloes expected in a subhalo that has a mass similar to NGC 205. We made Monte Carlo samplings and found that, using a set of reference parameters, the probability of producing a thinner distribution of sub-subhaloes than the observed NGC 205 + 15 smaller satellites (thus including the two counter-rotators, but excluding M32) increased from <10-8 for the initial distribution to ˜10-2 at pericentre. The probability of the simulated sub-subhaloes occupying the locations of the observed corotating satellites in the line-of-sight velocity versus projected on-sky distance plane is at most 2 × 10-3 for 11 out of 13 satellites. Increasing the mass of M31 and the extent of the initial distribution of sub-subhaloes gives a maximum probability of 4 × 10-3 for all 13 corotating satellites, but the probability of producing the thinness would drop to ˜10-3.

  2. Transiting exoplanets from the CoRoT space mission - XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit

    CERN Document Server

    Rouan, D; Moutou, C; Deleuil, M; Fridlund, M; Ofir, A; Havel, M; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Bonomo, A; Bordé, P; Bouchy, F; Cabrera, J; Cavarroc, C; Csizmadia, Sz; Deeg, H; Diaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Gillon, M; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Léger, A; Llebaria, A; Lammer, H; Lovis, C; Mazeh, T; Ollivier, M; Pätzold, M; Queloz, D; Rauer, H; Samuel, B; Santerne, A; Schneider, J; Tingley, B; Wuchterl, G

    2011-01-01

    We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 \\pm 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were used to derive stellar and planetary parameters. The planet has a mass of Mp = 2.8 \\pm 0.3 MJup, a radius of Rpl = 1.05 \\pm 0.13 RJup, a density of \\approx 3 g cm-3. RV data also clearly reveal a non zero eccentricity of e = 0.16 \\pm 0.02. The planet orbits a mature G0 main sequence star of V =15.5 mag, with a mass M\\star = 1.14 \\pm 0.08 M\\odot, a radius R\\star = 1. 61 \\pm 0.18 R\\odot and quasi-solar abundances. The age of the system is evaluated to be 7 Gyr, not far from the transition to subgiant, in agreement with the r...

  3. Transiting exoplanets from the CoRoT space mission. XX. CoRoT-18b: a massive hot jupiter on a prograde, nearly aligned orbit

    CERN Document Server

    Hebrard, G; Alonso, R; Fridlund, M; Ofir, A; Aigrain, S; Guillot, T; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Cabrera, J; Carone, L; Carpano, S; Cavarroc, C; Csizmadia, Sz; Deeg, H J; Deleuil, M; Diaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Gibson, N; Gillon, M; Guenther, E; Hatzes, A; Havel, M; Jorda, L; Lammer, H; Leger, A; Llebaria, A; Mazeh, T; Moutou, C; Ollivier, M; Parviainen, H; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Tingley, B; Wuchterl, G

    2011-01-01

    We report the detection of CoRoT-18b, a massive hot jupiter transiting in front of its host star with a period of 1.9000693 +/- 0.0000028 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite combined with spectroscopic and photometric follow-up ground-based observations. The planet has a mass M_p = 3.47 +/- 0.38 M_Jup, a radius R_p = 1.31 +/- 0.18 R_Jup, and a density rho_p = 2.2 +/- 0.8 g/cm3. It orbits a G9V star with a mass M_* = 0.95 +/- 0.15 M_Sun, a radius R_* = 1.00 +/- 0.13 R_Sun, and a rotation period P_rot = 5.4 +/- 0.4 days. The age of the system remains uncertain, stellar evolution models pointing either to a few tens Ma or several Ga, while gyrochronology and lithium abundance point towards ages of a few hundred Ma. This mismatch potentially points to a problem in our understanding of the evolution of young stars, with possible significant implications for stellar physics and the interpretation of inferred sizes of exoplanets around young stars. We detected...

  4. Transiting exoplanets from the CoRoT space mission: XXIV. CoRoT-24: A transiting multi-planet system

    CERN Document Server

    Alonso, R; Endl, M; Almenara, J M; Guenther, E W; Deleuil, M; Hatzes, A; Aigrain, S; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Cavarroc, C; Cabrera, J; Carpano, S; Csizmadia, Sz; Cochran, W D; Deeg, H J; Díaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Fruth, T; Gandolfi, D; Gillon, M; Grziwa, S; Guillot, T; Hébrard, G; Jorda, L; Léger, A; Lammer, H; Lovis, C; MacQueen, P J; Mazeh, T; Ofir, A; Ollivier, M; Pasternacki, T; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Santos, M Tadeu dos; Tingley, B; Titz-Weider, R; Weingrill, J; Wuchterl, G

    2014-01-01

    We present the discovery of a candidate multiply-transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76d are detected in the CoRoT light curve, around a main sequence K1V star of r=15.1. If the features are due to transiting planets around the same star, these would correspond to objects of 3.7$\\pm$0.4 and 5.0$\\pm$0.5 R_earth respectively. Several radial velocities serve to provide an upper limit of 5.7 M_earth for the 5.11~d signal, and to tentatively measure a mass of 28$^{+11}_{-11}$ M_earth for the object transiting with a 11.76~d period. These measurements imply low density objects, with a significant gaseous envelope. The detailed analysis of the photometric and spectroscopic data serve to estimate the probability that the observations are caused by transiting Neptune-sized planets as $>$26$\\times$ higher than a blend scenario involving only one transiting planet, and $>$900$\\times$ higher than a scenario involving two blends and no planets....

  5. The CoRoT discovery of a unique triple-mode cepheid in the galaxy

    CERN Document Server

    Poretti, Ennio; Weiss, Werner W

    2014-01-01

    The exploitation of the CoRoT treasure of stars observed in the exoplanetary field allowed the detection of a unusual triple-mode Cepheid in the Milky Way, CoRoT 0223989566. The two modes with the largest amplitudes and period ratio of 0.80 are identified with the first (P1=1.29 d) and second (P2=1.03 d) radial overtones. The third period, which has the smallest amplitude but able to produce combination terms with the other two, is the longest one (P3=1.89 d). The ratio of 0.68 between the first-overtone period and the third period is the unusual feature. Its identification with the fundamental radial or a nonradial mode is discussed with respect to similar cases in the Magellanic Clouds. In both cases the period triplet and the respective ratios make the star unique in our Galaxy. The distance derived from the period-luminosity relation and the galactic coordinates put CoRoT~0223989566 in the metal-rich environment of the "outer arm" of the Milky Way.

  6. On the width and shape of the corotation region for low-mass planets

    CERN Document Server

    Paardekooper, S -J

    2009-01-01

    We study the coorbital flow for embedded, low mass planets. We provide a simple semi-analytic model for the corotation region, which is subsequently compared to high resolution numerical simulations. The model is used to derive an expression for the half-width of the horseshoe region, x_s, which in the limit of zero softening is given by x_s/r_p = 1.68(q/h)^(1/2), where q is the planet to central star mass ratio, h is the disc aspect ratio and r_p the orbital radius. This is in very good agreement with the same quantity measured from simulations. This result is used to show that horseshoe drag is about an order of magnitude larger than the linear corotation torque in the zero softening limit. Thus the horseshoe drag, the sign of which depends on the gradient of specific vorticity, is important for estimates of the total torque acting on the planet. We further show that phenomena, such as the Lindblad wakes, with a radial separation from corotation of ~ a pressure scale height H can affect x_s, even though for...

  7. Exploring the helium core of the delta Scuti star CoRoT 102749568 with asteroseismology

    CERN Document Server

    Chen, Xinghao; Lin, Guifang; Chen, Yanhui; Guo, Junjun

    2016-01-01

    Based on regularities in rotational splittings, we seek possible multiplets for the observed frequencies of CoRoT 102749568. Twenty-one sets of multiplets are identified, including four sets of multiplets with $l=1$, nine sets of multiplets with $l=2$, and eight sets of multiplets with $l=3$. In particular, there are three complete triplets ($f_{10}$, $f_{12}$, $f_{14}$), ($f_{31}$, $f_{34}$, $f_{35}$), and ($f_{41}$, $f_{43}$, $f_{44}$). The rotational period of CoRoT 102749568 is estimated to be $1.34^{+0.04}_{-0.05}$ days. When doing model fittings, three $l=1$ modes ($f_{12}$, $f_{34}$, and $f_{43}$) and the radial first overtone $f_{13}$ are used. Our results shows that the three nonradial modes ($f_{12}$, $f_{34}$, and $f_{43}$) are mixed modes, which mainly provide constraints on the helium core. The radial first overtone $f_{13}$ mainly provides constraint on the stellar envelope. Hence the size of the helium core of CoRoT 102749568 is determined to be $M_{\\rm He}$ = 0.148 $\\pm$ 0.003 $M_{\\odot}$ and ...

  8. Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities

    Science.gov (United States)

    Faria, J. P.; Haywood, R. D.; Brewer, B. J.; Figueira, P.; Oshagh, M.; Santerne, A.; Santos, N. C.

    2016-04-01

    Stellar activity can induce signals in the radial velocities of stars, complicating the detection of orbiting low-mass planets. We present a method to determine the number of planetary signals present in radial-velocity datasets of active stars, using only radial-velocity observations. Instead of considering separate fits with different number of planets, we use a birth-death Markov chain Monte Carlo algorithm to infer the posterior distribution for the number of planets in a single run. In a natural way, the marginal distributions for the orbital parameters of all planets are also inferred. This method is applied to HARPS data of CoRoT-7. We confidently recover the orbits of both CoRoT-7b and CoRoT-7c although the data show evidence for the presence of additional signals. All data and software presented in this article are available online at http://https://github.com/j-faria/exoBD-CoRoT7

  9. Noise properties of the CoRoT data: a planet-finding perspective

    CERN Document Server

    Aigrain, S; Fressin, F; Alapini, A; Alonso, R; Auvergne, M; Barbieri, M; Barge, P; Borde, P; Bouchy, F; Deeg, H; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Fridlund, M; Gondoin, P; Guterman, P; Jorda, L; Lammer, H; Léger, A; llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Paezold, M; Queloz, D; Rauer, H; Rouan, D; Schneider, J; Wuchterl, G; Zucker, S

    2009-01-01

    In this short paper, we study the photometric precision of stellar light curves obtained by the CoRoT satellite in its planet finding channel, with a particular emphasis on the timescales characteristic of planetary transits. Together with other articles in the same issue of this journal, it forms an attempt to provide the building blocks for a statistical interpretation of the CoRoT planet and eclipsing binary catch to date. After pre-processing the light curves so as to minimise long-term variations and outliers, we measure the scatter of the light curves in the first three CoRoT runs lasting more than 1 month, using an iterative non-linear filter to isolate signal on the timescales of interest. The bevhaiour of the noise on 2h timescales is well-described a power-law with index 0.25 in R-magnitude, ranging from 0.1mmag at R=11.5 to 1mmag at R=16, which is close to the pre-launch specification, though still a factor 2-3 above the photon noise due to residual jitter noise and hot pixel events. There is evide...

  10. BEER analysis of Kepler and CoRoT light curves. III. Spectroscopic confirmation of seventy new beaming binaries discovered in CoRoT light curves

    Science.gov (United States)

    Tal-Or, L.; Faigler, S.; Mazeh, T.

    2015-08-01

    Context. The BEER algorithm searches stellar light curves for the BEaming, Ellipsoidal, and Reflection photometric modulations that are caused by a short-period companion. These three effects are typically of very low amplitude and can mainly be detected in light curves from space-based photometers. Unlike eclipsing binaries, these effects are not limited to edge-on inclinations. Aims: Applying the algorithm to wide-field photometric surveys such as CoRoT and Kepler offers an opportunity to better understand the statistical properties of short-period binaries. It also widens the window for detecting intrinsically rare systems, such as short-period brown-dwarf and massive-planetary companions to main-sequence stars. Methods: Applying the search to the first five long-run center CoRoT fields, we identified 481 non-eclipsing candidates with periodic flux amplitudes of 0.5-87 mmag. Optimizing the Anglo-Australian-Telescope pointing coordinates and the AAOmega fiber-allocations with dedicated softwares, we acquired six spectra for 231 candidates and seven spectra for another 50 candidates in a seven-night campaign. Analysis of the red-arm AAOmega spectra, which covered the range of 8342-8842 Å, yielded a radial-velocity precision of ~1 km s-1. Spectra containing lines of more than one star were analyzed with the two-dimensional correlation algorithm TODCOR. Results: The measured radial velocities confirmed the binarity of seventy of the BEER candidates - 45 single-line binaries, 18 double-line binaries, and 7 diluted binaries. We show that red giants introduce a major source of false candidates and demonstrate a way to improve BEER's performance in extracting higher fidelity samples from future searches of CoRoT light curves. The periods of the confirmed binaries span a range of 0.3-10 days and show a rise in the number of binaries per ΔlogP toward longer periods. The estimated mass ratios of the double-line binaries and the mass ratios assigned to the single

  11. The solar-like CoRoT target HD 170987: spectroscopic and seismic observations

    DEFF Research Database (Denmark)

    Mathur , S; Karoff, Christoffer

    2010-01-01

    that are lower than predicted. We present here the results from the analysis of the star HD 170987. Aims: The goal of this research work is to characterise the global parameters of HD 170987. We look for global seismic parameters such as the mean large separation, maximum amplitude of the modes, and surface...... rotation because the signal-to-noise ratio in the observations does not allow us to measure individual modes. We also aim to retrieve the parameters of the star and its chemical composition. Methods: We studied the chemical composition of the star through ground-based observations performed with the NARVAL......-1200] μHz with a mean large separation of 55.2 ± 0.8 μHz with a probability above 95 % that increases to 55.9 ± 0.2 μHz in a higher frequency range [500-1250] μHz and a rejection level of 1%. A hint of the variation of this quantity with frequency was also found. The rotation period of the star...

  12. Evidence that levels of the dimeric cellular transcription factor CP2 play little role in the activation of the HIV-1 long terminal repeat in vivo or following superinfection with herpes simplex virus type 1.

    Science.gov (United States)

    Zhong, F; Swendeman, S L; Popik, W; Pitha, P M; Sheffery, M

    1994-08-19

    The dimeric transcription factor CP2 binds a sequence element found near the transcription start site of the human immunodeficiency virus (HIV-1) long terminal repeat. Several groups have suggested that cellular factors binding this element might play a role in modulating HIV-1 promoter activity in vivo. For example, induction of latent HIV-1 gene expression in response to superinfection by herpes simplex virus type 1 (HSV-1) or cytomegalovirus is thought to be mediated, in part, by factors binding the CP2 site. In this report we began to examine directly the relationship between CP2 and expression of the HIV-1 promoter. First, we tested what effect HSV-1 infection of T cells had on the cellular levels of CP2. The results showed that HSV-1 infection led to a significant reduction in the level of CP2 DNA binding activity and protein within 20 h. Next, we tested the effect of overexpressing either the wild-type factor or a dominant negative variant of CP2 on HIV-1 promoter activity in vivo. The results showed that CP2 had little effect or slightly repressed HIV-1 promoter activity in vivo. In addition, these expression constructs had little effect on the induction of HIV-1 promoter activity elicited by HSV-1 infection.

  13. The CoRoT B-type binary HD 50230: a prototypical hybrid pulsator with g-mode period and p-mode frequency spacings⋆

    Science.gov (United States)

    Degroote, P.; Aerts, C.; Michel, E.; Briquet, M.; Pápics, P. I.; Amado, P.; Mathias, P.; Poretti, E.; Rainer, M.; Lombaert, R.; Hillen, M.; Morel, T.; Auvergne, M.; Baglin, A.; Baudin, F.; Catala, C.; Samadi, R.

    2012-06-01

    Context. B-type stars are promising targets for asteroseismic modelling, since their frequency spectrum is relatively simple. Aims: We deduce and summarise observational constraints for the hybrid pulsator, HD 50230, earlier reported to have deviations from a uniform period spacing of its gravity modes. The combination of spectra and a high-quality light curve measured by the CoRoT satellite allow a combined approach to fix the position of HD 50230 in the HR diagram. Methods: To describe the observed pulsations, classical Fourier analysis was combined with short-time Fourier transformations and frequency spacing analysis techniques. Visual spectra were used to constrain the projected rotation rate of the star and the fundamental parameters of the target. In a first approximation, the combined information was used to interpret multiplets and spacings to infer the true surface rotation rate and a rough estimate of the inclination angle. Results: We identify HD 50230 as a spectroscopic binary and characterise the two components. We detect the simultaneous presence of high-order g modes and low-order p and g-modes in the CoRoT light curve, but were unable to link them to line profile variations in the spectroscopic time series. We extract the relevant information from the frequency spectrum, which can be used for seismic modelling, and explore possible interpretations of the pressure mode spectrum. The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. Based on observations made with the ESO telescopes at La Silla Observatory under the ESO Large Programme LP182.D-0356, and on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, and on observations obtained with the HERMES

  14. MeCP2 suppresses LIN28A expression via binding to its methylated-CpG islands in pancreatic cancer cells.

    Science.gov (United States)

    Xu, Min; Bian, Shihui; Li, Jie; He, Junbo; Chen, Hui; Ge, Lu; Jiao, Zhijun; Zhang, Youli; Peng, Wanxin; Du, Fengyi; Mo, Yinyuan; Gong, Aihua

    2016-03-22

    LIN28A aberrant expression contributes to the development of human malignancies. However, the LIN28A expression profile remains to be clarified. Herein, we report that LIN28A expression is directly associated with the methylation status of its two CpG island sites in pancreatic cancer cells. First, Bisulfite sequencing reveals that PANC1 cells possess the higher methylation rate at LIN28A CpG islands compared with SW1990 and PaTu8988 cells. Subsequently, LIN28A expression is increased at both mRNA and protein levels in pancreatic cancer cells treated with 5-Aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor. Further Chromatin immunoprecipitation (ChIP) assays indicate that methyl-CpG-binding protein 2 (MeCP2) binds preferentially to the two hypermethylated CpG islands sites at LIN28A promoter compare to MBD3. Expectedly, MeCP2 knockdown transcriptionally activates LIN28A expression in above cells, rather than MBD3 knockdown. Moreover, LIN28A overexpression remarkably improves OCT4, NANOG and SOX2 expression, and the ability of sphere and colony formation, and enhances the capacities of invasion in PaTu8988 and SW1990 cells, whereas LIN28A knockdown significantly inhibits the above malignant behaviors in PANC1 cells. These findings suggest that LIN28A is epigenetically regulated via MeCP2 binding to methylated-CpG islands, and may play a crucial role in pancreatic cancer progression.

  15. The Effects of Maternal Separation on Adult Methamphetamine Self-Administration, Extinction, Reinstatement, and MeCP2 Immunoreactivity in the Nucleus Accumbens

    Directory of Open Access Journals (Sweden)

    Candace R. Lewis

    2013-06-01

    Full Text Available The maternal separation (MS paradigm is an animal model of early life stress. Animals subjected to MS during the first two weeks of life display altered behavioral and neuroendocrinological stress responses as adults. MS also produces altered responsiveness to and self-administration (SA of various drugs of abuse including cocaine, ethanol, opioids, and amphetamine. Methamphetamine (METH causes great harm to both the individual user and to society; yet, no studies have examined the effects of MS on METH SA. This study was performed to examine the effects of MS on the acquisition of METH SA, extinction, and reinstatement of METH-seeking behavior in adulthood. Given the known influence of early life stress and drug exposure on epigenetic processes, group differences in levels of the epigenetic marker methyl CpG binding protein 2 (MeCP2 in the nucleus accumbens (NAc core were also investigated. Long-Evans pups and dams were separated on postnatal days (PND 2-14 for either 180 (MS180 or 15 min (MS15. Male offspring were allowed to acquire METH SA (0.05 mg/kg/infusion in 15 2-hr daily sessions starting at PND67, followed by extinction training and cue-induced reinstatement of METH-seeking behavior. Rats were then assessed for MeCP2 levels in the NAc core by immunohistochemistry. The MS180 group self-administered significantly more METH and acquired SA earlier than the MS15 group. No group differences in extinction or cue-induced reinstatement were observed. MS15 rats had significantly elevated MeCP2-immunoreactive cells in the NAc core as compared to MS180 rats. Together, these data suggest that MS has lasting influences on METH SA as well as epigenetic processes in the brain reward circuitry.

  16. MeCP2 mutation results in compartment-specific reductions in dendritic branching and spine density in layer 5 motor cortical neurons of YFP-H mice.

    Directory of Open Access Journals (Sweden)

    David P Stuss

    Full Text Available Rett Syndrome (RTT is a neurodevelopmental disorder predominantly caused by mutations in the X-linked gene MECP2. A primary feature of the syndrome is the impaired maturation and maintenance of excitatory synapses in the central nervous system (CNS. Different RTT mouse models have shown that particular Mecp2 mutations have highly variable effects on neuronal architecture. Distinguishing MeCP2 mutant cellular phenotypes therefore demands analysis of specific mutations in well-defined neuronal subpopulations. We examined a transgenically labeled subset of cortical neurons in YFP-H mice crossed with the Mecp2(tm1.1Jae mutant line. YFP(+ Layer 5 pyramidal neurons in the motor cortex of wildtype and hemizygous mutant male mice were examined for differences in dendrite morphology and spine density. Total basal dendritic length was decreased by 18.6% due to both shorter dendrites and reduced branching proximal to the soma. Tangential dendrite lengths in the apical tuft were reduced by up to 26.6%. Spine density was reduced by 47.4% in the apical tuft and 54.5% in secondary apical dendrites, but remained unaffected in primary apical and proximal basal dendrites. We also found that MeCP2 mutation reduced the number of YFP(+ cells in YFP-H mice by up to 72% in various cortical regions without affecting the intensity of YFP expression in individual cells. Our results support the view that the effects of MeCP2 mutation are highly context-dependent and cannot be generalized across mutation types and cell populations.

  17. MicroRNA-144 is regulated by CP2 and decreases COX-2 expression and PGE2 production in mouse ovarian granulosa cells.

    Science.gov (United States)

    Zhou, Jiawei; Lei, Bin; Li, Huanan; Zhu, Lihua; Wang, Lei; Tao, Hu; Mei, Shuqi; Li, Fenge

    2017-02-09

    Mammalian folliculogenesis is a complex process in which primordial follicles develop into pre-ovulatory follicles, followed by ovulation to release mature oocytes. In this study, we explored the role of miR-144 in ovulation. miR-144 was one of the differentially expressed microRNAs, which showed 5.59-fold changes, in pre-ovulatory ovarian follicles between Large White and Chinese Taihu sows detected by Solexa deep sequencing. We demonstrated that overexpression of miR-144 significantly decreased the luciferase reporter activity under the control of the cyclooxygenase-2 (COX-2) or mothers against decapentaplegic homologue 4 (Smad4) 3'-untranslated region (3'-UTR) and suppressed COX-2 and Smad4 expression. In contrast, a miR-144 inhibitor increased COX-2 and Smad4 expression in mouse granulosa cells (mGCs). Meanwhile, Smad4 upregulated COX-2 expression, but this effect was abolished when the mGCs were treated with the transforming growth factor beta signalling pathway inhibitor SB431542. Moreover, luciferase reporter, chromatin immunoprecipitation and electrophoretic mobility shift assay results showed that the transcription factor CP2 upregulated miR-144 expression, which partially contributed to the suppression of COX-2 in mGCs. Both CP2 and miR-144 alter prostaglandin E2 (PGE2) production by regulating COX-2 expression. In addition, miR-144 regulated mGC apoptosis and affected follicular atresia, but these activities did not appear to be through COX-2 and Smad4. Taken together, we revealed an important CP2/miR-144/COX-2/PGE2/ovulation pathway in mGCs.

  18. Transiting exoplanets from the CoRoT space mission XIV. CoRoT-11b: a transiting massive "hot-Jupiter" in a prograde orbit around a rapidly rotating F-type star

    CERN Document Server

    Gandolfi, D; Alonso, R; Deleuil, M; Guenther, E W; Fridlund, M; Endl, M; Eigmüller, P; Csizmadia, Sz; Havel, M; Aigrain, S; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Carpano, S; Carone, L; Cochran, W D; Deeg, H J; Dvorak, R; Eislöffel, J; Erikson, A; Ferraz-Mello, S; Gazzano, J -C; Gibson, N P; Gillon, M; Gondoin, P; Guillot, T; Hartmann, M; Hatzes, A; Jorda, L; Kabath, P; Léger, A; Llebaria, A; Lammer, H; MacQueen, P J; Mayor, M; Mazeh, T; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Stecklum, B; Tingley, B; Udry, S; Wuchterl, G; 10.1051/0004-6361/201015132

    2010-01-01

    The CoRoT exoplanet science team announces the discovery of CoRoT-11b, a fairly massive hot-Jupiter transiting a V=12.9 mag F6 dwarf star (M*=1.27 +/- 0.05 Msun, R*=1.37 +/- 0.03 Rsun, Teff=6440 +/- 120 K), with an orbital period of P=2.994329 +/- 0.000011 days and semi-major axis a=0.0436 +/- 0.005 AU. The detection of part of the radial velocity anomaly caused by the Rossiter-McLaughlin effect shows that the transit-like events detected by CoRoT are caused by a planet-sized transiting object in a prograde orbit. The relatively high projected rotational velocity of the star (vsini=40+/-5 km/s) places CoRoT-11 among the most rapidly rotating planet host stars discovered so far. With a planetary mass of mp=2.33+/-0.34 Mjup and radius rp=1.43+/-0.03 Rjup, the resulting mean density of CoRoT-11b (rho=0.99+/-0.15 g/cm^3) can be explained with a model for an inflated hydrogen-planet with a solar composition and a high level of energy dissipation in its interior.

  19. The Drosophila tissue-specific factor Grainyhead contains novel DNA-binding and dimerization domains which are conserved in the human protein CP2.

    Science.gov (United States)

    Uv, A E; Thompson, C R; Bray, S J

    1994-06-01

    We have mapped the regions in the Drosophila melanogaster tissue-specific transcription factor Grainyhead that are required for DNA binding and dimerization. These functional domains correspond to regions conserved between Grainyhead and the vertebrate transcription factor CP2, which we show has similar activities. The identified DNA-binding domain is large (263 amino acids) but contains a smaller core that is able to interact with DNA at approximately 400-fold lower affinity. The major dimerization domain is located in a separate region of the protein and is required to stabilize the interactions with DNA. Our data also suggest that Grainyhead activity can be modulated by an N-terminal inhibitory domain.

  20. The Diphosphorus Complex [Cp2Mo2(CO)4(η(2)-P2)] as a Building Block for the Synthesis of Mixed-Hybrid Coordination Polymers.

    Science.gov (United States)

    Moussa, Mehdi Elsayed; Attenberger, Bianca; Fleischmann, Martin; Schreiner, Andrea; Scheer, Manfred

    2016-10-01

    The three-component reaction of the tetrahedral diphosphorus complex [Cp2Mo2(CO)4(η(2)-P2)] (1), with Ag[BF4] (2) in the presence of 2,2'-bipyrimidine (3) leads to the formation of the two novel two-dimensional networks 4 and 5. Compound 4 is a new two-dimensional organometallic-organic hybrid polymer, while derivative 5 represents a unique two-dimensional organometallic-inorganic-organic hybrid polymer. These results show the possibility of synthesizing a new class of coordination polymers, which could not be obtained from two-component reactions with organic molecules in addition of metal ions.

  1. CoRoT-10b: a giant planet in a 13.24 day eccentric orbit

    CERN Document Server

    Bonomo, A S; Alonso, R; Gazzano, J -C; Havel, M; Aigrain, S; Auvergne, M; Baglin, A; Barbieri, M; Barge, P; Benz, W; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Cameron, A C; Carone, L; Carpano, S; Csizmadia, Sz; Deleuil, M; Deeg, H J; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gillon, M; Guenther, E; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Lammer, H; Lanza, A F; Léger, A; Llebaria, A; Mayor, M; Mazeh, T; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Tingley, B; Udry, S; Wuchterl, G

    2010-01-01

    The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view. We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e=0.53 +/- 0.04) revolving in 13.24 days around a faint (V=15.22) metal-rich K1V star. We use CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star to derive the orbital, stellar and planetary parameters. We derive a radius of the planet of 0.97 +/- 0.07 R_Jup and a mass of 2.75 +/- 0.16 M_Jup. The bulk density, rho_pl=3.70 +/- 0.83 g/cm^3, is ~2.8 that of Jupiter. The core of CoRoT-10b could contain up to 240 M_Earth of heavy elements. Moving along its eccentric orbit, the planet experiences a 10.6-fold variation in insolation. Owing to the long circularisation time, tau_circ > 7 Gyr, a resonant perturber is not required to excite and maintain the high eccentricity of CoRoT-10b.

  2. Isoform-specific anti-MeCP2 antibodies confirm that expression of the e1 isoform strongly predominates in the brain [v1; ref status: indexed, http://f1000r.es/1mg

    Directory of Open Access Journals (Sweden)

    Lara Kaddoum

    2013-10-01

    Full Text Available Rett syndrome is a neurological disorder caused by mutations in the MECP2 gene.  MeCP2 transcripts are alternatively spliced to generate two protein isoforms (MeCP2_e1 and MeCP2_e2 that differ at their N-termini. Whilst mRNAs for both forms are expressed ubiquitously, the one for MeCP2_e1 is more abundant than for MeCP2_e2 in the central nervous system. In transfected cells, both protein isoforms are nuclear and colocalize with densely methylated heterochromatic foci. With a view to understanding the physiological contribution of each isoform, and their respective roles in the pathogenesis of Rett syndrome, we set out to generate isoform-specific anti-MeCP2 antibodies. To this end, we immunized rabbits against the peptides corresponding to the short amino-terminal portions that are different between the two isoforms. The polyclonal antibodies thus obtained specifically detected their respective isoforms of MeCP2 in Neuro2a (N2A cells transfected to express either form. Both antisera showed comparable sensitivities when used for Western blot or immunofluorescence, and were highly specific for their respective isoform. When those antibodies were used on mouse tissues, specific signals were easily detected for Mecp2_e1, whilst Mecp2_e2 was very difficult to detect by Western blot, and even more so by immunofluorescence. Our results thus suggest that brain cells express low amounts of the Mecp2-e2 isoform. Our findings are compatible with recent reports showing that MeCP2_e2 is dispensable for healthy brain function, and that it may be involved in the regulation of neuronal apoptosis and embryonic development.

  3. (nBuCp)2ZrCl2-catalyzed Ethylene-4M1P Copolymerization: Copolymer Backbone Structure, Melt Behavior, and Crystallization

    KAUST Repository

    Atiqullah, Muhammad

    2016-01-08

    The judicious design of methylaluminoxane (MAO) anions expands the scope for developing industrial metallocene catalysts. Therefore, the effects of MAO anion design on the backbone structure, melt behavior, and crystallization of ethylene−4-methyl-1-pentene (E−4M1P) copolymer were investigated. Ethylene was homopolymerized, as well as copolymerized with 4M1P, using (i) MAO anion A (unsupported [MAOCl2]−) premixed with dehydroxylated silica, (nBuCp)2ZrCl2, and Me2SiCl2; and (ii) MAO anion B (Si−O−Me2Si−[MAOCl2]−) supported with (nBuCp)2ZrCl2 on Me2SiCl2-functionalized silica. Unsupported Me2SiCl2, opposite to the supported analogue, acted as a co-chain transfer agent with 4M1P. The modeling of polyethylene melting and crystallization kinetics, including critical crystallite stability, produced insightful results. This study especially illustrates how branched polyethylene can be prepared from ethylene alone using particularly one metallocene-MAO ion pair, and how a compound, that functionalizes silica as well as terminates the chain, can synthesize ethylene−α-olefin copolymers with novel structures. Hence, it unfolds prospective future research niches in polyethyne systhesis. This article is protected by copyright. All rights reserved.

  4. Charge Quantization and the Standard Model from the $\\mathbb{CP}^2$ and $\\mathbb{CP}^3$ Nonlinear $\\sigma$-Models

    CERN Document Server

    Hellerman, Simeon; Yanagida, Tsutomu T

    2013-01-01

    We investigate charge quantization in the Standard Model (SM) through a $\\mathbb{CP}^2$ nonlinear sigma model (NLSM), $SU(3)_G/(SU(2)_H \\times U(1)_H)$, and a $\\mathbb{CP}^3$ model, $SU(4)_G/(SU(3)_H \\times U(1)_H)$. We also generalize to any $\\mathbb{CP}^k$ model. Charge quantization follows from the consistency and dynamics of the NLSM, without a monopole or Grand Unified Theory, as shown in our earlier work on the $\\mathbb{CP}^1$ model (arXiv:1309.0692). We find that representations of the matter fields under the unbroken non-abelian subgroup dictate their charge quantization under the $U(1)_H$ factor. In the $\\mathbb{CP}^2$ model the unbroken group is identified with the weak and hypercharge groups of the SM, and the Nambu-Goldstone boson (NGB) has the quantum numbers of a SM Higgs. There is the intriguing possibility of a connection with the vanishing of the Higgs self-coupling at the Planck scale. Interestingly, with some minor assumptions (no vector-like matter and minimal representations) and starting...

  5. Theoretical Studies on the Bonding Properties of Metal-metal Multiple Bond of Cp2 M2(μ-B4 N4 H8) (M=V,Cr,Mn,Fe)%Cp2M2(μ-B4N4H8)(M=V,Cr,Mn,Fe)金属多重键成键性质的理论研究

    Institute of Scientific and Technical Information of China (English)

    刘楠楠; 丁益宏

    2014-01-01

    对金属多重键配合物Cp2M2(μ-B4N4H8)(M=V, Cr, Mn, Fe)的结构和成键进行了理论研究,并与Cp2 M2(μ-C8 H8)进行对比.计算结果表明,在Cp2 M2(μ-B4 N4 H8)基态构型中, B4 N4 H8配体均以硼为桥原子,金属原子的配位数均为5.其中, Cp2M2(μ-B4N4H8)(M=V, Cr, Mn)基态的结构和成键都与Cp2M2(μ-C8H8)非常接近;而Cp2Fe2(μ-B4N4H8)基态结构与Fe为4配位的Cp2Fe2(μ-C8H8)有所不同. Cp2M2(μ-B4N4H8)( M=V, Cr, Mn, Fe)基态结构分别为含V-V三重键的三态、含Cr-Cr三重键的单态、含Mn-Mn双键的三态及含Fe-Fe单键的单态.%The geometry and bonding of metal-metal multiple bond complexes Cp2 M2 (μ-B4 N4 H8 ) ( M=V, Cr, Mn, Fe) were theoretically investigated and compared with Cp2 M2(μ-C8 H8 ) . The calculated results show that in the ground states of Cp2 M2 (μ-B4 N4 H8 ) , the ligands B4 N4 H8 are all with B bridging atoms, the coordination numbers of M atom are all five. Among them, the structure and bonding of ground state of Cp2 M2(μ-B4 N4 H8 ) ( M = V, Cr, Mn ) are very close to Cp2 M2 (μ-C8 H8 ); while the ground state of Cp2 Fe2(μ-B4 N4 H8 ) is different with Cp2 Fe2 (μ-C8 H8 ) containing four-coordinated Fe. The ground-states of Cp2 M2(μ-B4 N4 H8 ) ( M=V, Cr, Mn, Fe) are respectively triplet state with V-V triple bond, singlet state with Cr-Cr triple bond, triplet state with Mn-Mn double bond, and singlet state with Fe-Fe single bond.

  6. Investigation of melting in a modular intermeshing co-rotating twin screw extruder

    Science.gov (United States)

    Jung, Ho-Chul

    Since the first patent regarding the co-rotating twin screw extruder was published in 1869, the co-rotating twin screw extruder has evolved into a high performance extruder, having self wiping capability, modular screw configuration, starved feed zone, kneading disc block elements, and special mixing devices. For this device, flow studies began in the mid 1960's but melting studies started in the early 1990's. Former researchers have insisted on their own melting mechanisms because they found different melting mechanisms under their limited and unsystematic experimental conditions. In this dissertation, melting mechanisms were studied systemically to determine when they occur according to the various process operating conditions. This melting study was carried out using an amorphous polymer: polystyrene (PS), two semi-crystalline polymers: linear low density polyethylene (LLDPE) and polypropylene (PP), one powder type LLDPE, and four LLDPE compounds with aluminum flake or calcium carbonate, which were used to provide differences in filler size or content. We observed the screw melting initiation and melting propagation first and categorized melting regimes such as screw melting initiation (SM) internal melting initiation (IM) and barrel melting initiation (BM) as melting initiation mechanisms, and screw melting propagation internal melting propagation barrel melting propagation and bed instability (BI) as melting propagation mechanisms. We translated these melting initiation mechanisms and melting propagation mechanisms into mathematical models. Then we integrated these models into user friendly commercial software, Akro-Co-Twin ScrewR, developed previously at our laboratories. We simulated several homopolymers at various operating conditions using the Akro-Co-Twin ScrewR. The simulation results were compared with the experimental results and were found to be in good agreement within the range of simulation. Using this software, twin screw extruder process

  7. Estudo da preparação do catalisador Cp2ZrCl2 suportado em sílica utilizando um planejamento de experimentos Preparation conditions of Cp2ZrCl2 supported on silica using an experimental planning

    Directory of Open Access Journals (Sweden)

    Anunciata Conte

    2001-03-01

    Full Text Available O monômero eteno foi polimerizado através dos sistemas catalíticos Cp2ZrCl2/SiO2 e Cp2ZrCl2/MAO/SiO2. Foi elaborado um planejamento estatístico de experimentos a fim de se identificar as melhores condições de preparo dos catalisadores heterogêneos. As variáveis utilizadas foram a concentração de metilaluminoxano (MAO no pré-tratamento do suporte, a concentração e a temperatura de imobilização do metaloceno. Os catalisadores suportados foram analisados por espectrometria de emissão com plasma acoplado indutivamente e as resinas produzidas foram caracterizadas por cromatografia de permeação em gel (GPC e calorimetria de varredura diferencial (DSC. Foi observado que quanto maior a concentração de zircônio fixada na superfície do suporte, menor foi a atividade catalítica, na faixa de variáveis estudadas.Ethylene was polymerized with the catalytic systems Cp2ZrCl2/SiO2 and Cp2ZrCl2/MAO/SiO2. A experimental planning model was developed in order to identify the best conditions for the preparation of metallocene heterogeneous catalysts. The variables used were methylaluminoxane (MAO concentration of the support treatment, concentration and temperature of metallocene immobilization. The supported catalysts were analyzed by inductively coupled plasma emission spectometry and the polyethylene (PE produced was characterized by gel permeation calorimetry (GPC and differential scanning calorimetry (DSC. It was observed that the higher the zirconium concentration fixed on the support surface, the lower the catalyst activity, in the studied variables range.

  8. 水稻半胱氨酸蛋白酶OsCP2的特征分析及其原核表达与纯化%Cnaracterization, Prokaryotic Expression and Purification of a Rice Cysteine Protease OsCP2

    Institute of Scientific and Technical Information of China (English)

    严秀蕊; 张大生; 梁婉琪; 王玉炯; 张大兵

    2010-01-01

    半胱氨酸蛋白酶是植物体中重要的蛋白水解酶,广泛参与种子萌发、幼苗发育、胁迫响应和组织分化衰老等生理过程.我们对水稻中半胱氨酸蛋白酶基因OsCF2 (Oryza sativa cysteine protease 2)序列进行分析.该基因cDNA全长2 279 bp,由2个外显子和1个内含子组成;包含1个1 089 bp的开放读码框,编码1个含362个氨基酸残基的蛋白,在蛋白氨基端有-36个氨基酸组成的信号肽.生物信息学分析表明,OsCP2与大麦半胱氨酸蛋白酶HvCP同源性最高,同属木瓜蛋白酶亚家族.另外,我们构建了pET32a/CP2原核.表达载体,通过转化大肠杆菌BL21DE3,成功表达了OsCP2重组蛋白.分子量约为58kD;通过纯化包涵体获得了纯度高达90%以上的重组OsCP2蛋白,这为进一步研究该基因的功能提供了基础.

  9. Phase-Averaged Method Applied to Periodic Flow Between Shrouded Corotating Disks

    Directory of Open Access Journals (Sweden)

    Shen-Chun Wu

    2003-01-01

    Full Text Available This study investigates the coherent flow fields between corotating disks in a cylindrical enclosure. By using two laser velocimeters and a phase-averaged technique, the vortical structures of the flow could be reconstructed and their dynamic behavior was observed. The experimental results reveal clearly that the flow field between the disks is composed of three distinct regions: an inner region near the hub, an outer region, and a shroud boundary layer region. The outer region is distinguished by the presence of large vortical structures. The number of vortical structures corresponds to the normalized frequency of the flow.

  10. Rotation period distribution of CoRoT and Kepler Sun-like stars

    Science.gov (United States)

    Leão, I. C.; Pasquini, L.; Ferreira Lopes, C. E.; Neves, V.; Valcarce, A. A. R.; de Oliveira, L. L. A.; Freire da Silva, D.; de Freitas, D. B.; Canto Martins, B. L.; Janot-Pacheco, E.; Baglin, A.; De Medeiros, J. R.

    2015-10-01

    Aims: We study the distribution of the photometric rotation period (Prot), which is a direct measurement of the surface rotation at active latitudes, for three subsamples of Sun-like stars: one from CoRoT data and two from Kepler data. For this purpose, we identify the main populations of these samples and interpret their main biases specifically for a comparison with the solar Prot. Methods: Prot and variability amplitude (A) measurements were obtained from public CoRoT and Kepler catalogs, which were combined with public data of physical parameters. Because these samples are subject to selection effects, we computed synthetic samples with simulated biases to compare with observations, particularly around the location of the Sun in the Hertzsprung-Russel (HR) diagram. Publicly available theoretical grids and empirical relations were used to combine physical parameters with Prot and A. Biases were simulated by performing cutoffs on the physical and rotational parameters in the same way as in each observed sample. A crucial cutoff is related with the detectability of the rotational modulation, which strongly depends on A. Results: The synthetic samples explain the observed Prot distributions of Sun-like stars as having two main populations: one of young objects (group I, with ages younger than ~1 Gyr) and another of main-sequence and evolved stars (group II, with ages older than ~1 Gyr). The proportions of groups I and II in relation to the total number of stars range within 64-84% and 16-36%, respectively. Hence, young objects abound in the distributions, producing the effect of observing a high number of short periods around the location of the Sun in the HR diagram. Differences in the Prot distributions between the CoRoT and Kepler Sun-like samples may be associated with different Galactic populations. Overall, the synthetic distribution around the solar period agrees with observations, which suggests that the solar rotation is normal with respect to Sun

  11. Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model

    Science.gov (United States)

    Anders, F.; Chiappini, C.; Rodrigues, T. S.; Piffl, T.; Mosser, B.; Miglio, A.; Montalbán, J.; Girardi, L.; Minchev, I.; Valentini, M.; Steinmetz, M.

    2016-09-01

    In a companion paper, we have presented the combined asteroseismic-spectroscopic dataset obtained from CoRoT light curves and APOGEE infra-red spectra for 606 solar-like oscillating red giants in two fields of the Galactic disc (CoRoGEE). We have measured chemical abundance patterns, distances, and ages of these field stars which are spread over a large radial range of the Milky Way's disc. Here we show how to simulate this dataset using a chemodynamical Galaxy model. We also demonstrate how the observation procedure influences the accuracy of our estimated ages.

  12. Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model

    CERN Document Server

    Anders, F; Rodrigues, T S; Piffl, T; Mosser, B; Miglio, A; Montalbán, J; Girardi, L; Minchev, I; Valentini, M; Steinmetz, M

    2016-01-01

    In a companion paper, we have presented the combined asteroseismic-spectroscopic dataset obtained from CoRoT lightcurves and APOGEE infra-red spectra for 678 solar-like oscillating red giants in two fields of the Galactic disc (CoRoGEE). We have measured chemical abundance patterns, distances, and ages of these field stars which are spread over a large radial range of the Milky Way's disc. Here we show how to simulate this dataset using a chemodynamical Galaxy model. We also demonstrate how the observation procedure influences the accuracy of our estimated ages.

  13. Recurrent variations of anomalous oxygen in association with a corotating interaction region

    Directory of Open Access Journals (Sweden)

    M. K. Reuss

    Full Text Available The fluxes of anomalous oxygen (E ranging from 3.5-6.8 MeV/amu, as measured by the EPAC instrument on ULYSSES, show a recurrent variation with the solar rotation period, which is anticorrelated with the fluxes of particles accelerated at the shocks of a corotating interaction region (CIR, and correlated with the fluxes of galactic cosmic rays known to be modulated by the CIR. The amplitude of this variation is much higher than expected for galactic cosmic rays of the same rigidity.

  14. Transiting exoplanets from the CoRoT space mission. XII. CoRoT-12b: a short-period low-density planet transiting a solar analog star

    CERN Document Server

    Gillon, M; Csizmadia, Sz; Fridlund, M; Deleuil, M; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Barnes, S I; Bonomo, A S; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Carone, L; Carpano, S; Cochran, W D; Deeg, H J; Dvorak, R; Endl, M; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Gazzano, J C; Guenther, E; Guillot, T; Havel, M; Hébrard, G; Jorda, L; Léger, A; Llebaria, A; Lammer, H; Lovis, C; Mayor, M; Mazeh, T; Montalbán, J; Moutou, C; Ofir, A; Ollivier, M; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Santerne, A; Schneider, J; Tingley, B; Udry, S; Weingrill, J; Wuchterl, G

    2010-01-01

    We report the discovery by the CoRoT satellite of a new transiting giant planet in a 2.83 days orbit about a V=15.5 solar analog star (M_* = 1.08 +- 0.08 M_sun, R_* = 1.1 +- 0.1 R_sun, T_eff = 5675 +- 80 K). This new planet, CoRoT-12b, has a mass of 0.92 +- 0.07 M_Jup and a radius of 1.44 +- 0.13 R_Jup. Its low density can be explained by standard models for irradiated planets.

  15. Transiting exoplanets from the CoRoT space mission XXVIII. CoRoT-28b, a planet orbiting an evolved star, and CoRoT-29b, a planet showing an asymmetric transit

    CERN Document Server

    Cabrera, J; Montagnier, G; Fridlund, M; Eiff, M Ammler-von; Chaintreuil, S; Damiani, C; Deleuil, M; Ferraz-Mello, S; Ferrigno, A; Gandolfi, D; Guillot, T; Guenther, E W; Hatzes, A; Hébrard, G; Klagyivik, P; Parviainen, H; Pasternacki, Th; Pätzold, M; Sebastian, D; Santos, M Tadeu dos; Wuchterl, G; Aigrain, S; Alonso, R; Almenara, J -M; Armstrong, J D; Auvergne, M; Baglin, A; Barge, P; Barros, S C C; Bonomo, A S; Bordé, P; Bouchy, F; Carpano, S; Chaffey, C; Deeg, H J; Díaz, R F; Dvorak, R; Erikson, A; Grziwa, S; Korth, J; Lammer, H; Lindsay, C; Mazeh, T; Moutou, C; Ofir, A; Ollivier, M; Pallé, E; Rauer, H; Rouan, D; Samuel, B; Santerne, A; Schneider, J

    2015-01-01

    Context. We present the discovery of two transiting extrasolar planets by the satellite CoRoT. Aims. We aim at a characterization of the planetary bulk parameters, which allow us to further investigate the formation and evolution of the planetary systems and the main properties of the host stars. Methods. We used the transit light curve to characterize the planetary parameters relative to the stellar parameters. The analysis of HARPS spectra established the planetary nature of the detections, providing their masses. Further photometric and spectroscopic ground-based observations provided stellar parameters (log g,Teff,v sin i) to characterize the host stars. Our model takes the geometry of the transit to constrain the stellar density into account, which when linked to stellar evolutionary models, determines the bulk parameters of the star. Because of the asymmetric shape of the light curve of one of the planets, we had to include the possibility in our model that the stellar surface was not strictly spherical...

  16. How to separate the low amplitude delta Scuti variation from the instrumental ones in CoRoT data?

    CERN Document Server

    Benkő, J M

    2016-01-01

    Rich regular frequency patterns were found in the Fourier spectra of low-amplitude delta Scuti stars observed by CoRoT satellite (see Papar\\'o et al. 2016a,b). The CoRoT observations are, however, influenced by the disturbing effect of the South Atlantic Anomaly. The effect is marginal for high amplitude variable stars but it could be critical in the case of low amplitude variables, especially if the frequency range of the intrinsic variation overlaps the interval of the instrumental frequencies. Some tests were carried out both on synthetic and real data for distinguishing technical and stars' frequencies.

  17. Transcriptional Regulation of Brain-Derived Neurotrophic Factor (BDNF) by Methyl CpG Binding Protein 2 (MeCP2): a Novel Mechanism for Re-Myelination and/or Myelin Repair Involved in the Treatment of Multiple Sclerosis (MS).

    Science.gov (United States)

    KhorshidAhmad, Tina; Acosta, Crystal; Cortes, Claudia; Lakowski, Ted M; Gangadaran, Surendiran; Namaka, Michael

    2016-03-01

    Multiple sclerosis (MS) is a chronic progressive, neurological disease characterized by the targeted immune system-mediated destruction of central nervous system (CNS) myelin. Autoreactive CD4+ T helper cells have a key role in orchestrating MS-induced myelin damage. Once activated, circulating Th1-cells secrete a variety of inflammatory cytokines that foster the breakdown of blood-brain barrier (BBB) eventually infiltrating into the CNS. Inside the CNS, they become reactivated upon exposure to the myelin structural proteins and continue to produce inflammatory cytokines such as tumor necrosis factor α (TNFα) that leads to direct activation of antibodies and macrophages that are involved in the phagocytosis of myelin. Proliferating oligodendrocyte precursors (OPs) migrating to the lesion sites are capable of acute remyelination but unable to completely repair or restore the immune system-mediated myelin damage. This results in various permanent clinical neurological disabilities such as cognitive dysfunction, fatigue, bowel/bladder abnormalities, and neuropathic pain. At present, there is no cure for MS. Recent remyelination and/or myelin repair strategies have focused on the role of the neurotrophin brain-derived neurotrophic factor (BDNF) and its upstream transcriptional repressor methyl CpG binding protein (MeCP2). Research in the field of epigenetic therapeutics involving histone deacetylase (HDAC) inhibitors and lysine acetyl transferase (KAT) inhibitors is being explored to repress the detrimental effects of MeCP2. This review will address the role of MeCP2 and BDNF in remyelination and/or myelin repair and the potential of HDAC and KAT inhibitors as novel therapeutic interventions for MS.

  18. 子宫内膜癌患者血清CP2、CA125、唾液酸和癌胚抗原检测的临床意义%Clinical significance of serum CP2, CA125, salicylic acid and carcinoembryonic antigen in endometrial carcinoma

    Institute of Scientific and Technical Information of China (English)

    王志启; 王建六; 杨静华; 魏丽惠

    2008-01-01

    Objective To explore the clinical significance of CP2,CA125,salicylic acid(SA)and carcinoembryonic antigen(CEA)in endometrial carcinoma patients. Methods A retrospective study was carried out on 154 cases of endometrial carcinoma with tumor markers test results who were admitted to our department from Aug 1992 to Nov 2004.Results The patients were followed up for(38±28)months.23.4%,36.8%,19.0%and 30.3%of cases were with abnormal values of CP2,SA,CA125 and CEA.CP2 abnormal level was related with the stage,cell differentiation,adnexa metastasis,positive peritoneal cytology and pelvic lymph node metastasis(P=0.002,P=0.040,P=0.019,P=0.019,P:0.005).SA abnormal level was related with the adnexa metastasis and positive peritoneal eytology(P=0.021,P=0.000). CA125 abnormal level was related with the cell differentiation,cervical metastasis and pelvic lymph node metastasis(P=0.014,P=0.006,P=0.018).The survival was related with CP2,CA125 and CEA (P=0.016,P=0.000,P=0.016),especially CA125. Conclusions Among the commonly used tumor markers,CP2 is related with many clinical pathological parameters.CA125 elevation may strongly suggest worse prognosis.%目的 探讨肿瘤标志物CP2、CA125唾液酸(SA)和癌胚抗原(CEA)检测对子宫内膜癌患者的临床意义.方法 选取154例具有肿瘤标志物检测结果 的子宫内膜癌患者的临床病理资料进行回顾性分析.结果 子宫内膜癌患者血清CP2、SA、CA125和CEA水平升高的百分率分别为23.4%、36.8%、19.0%和30.3%.血清CP2水平升高与手术病理分期、病理分化程度、附件受累、腹腔细胞学检查阳性及盆腔淋巴结转移相关(P值分别为0.002、0.040、0.019、0.019、0.005);血清SA水平升高与附件受累、腹腔细胞学检查阳性相关(P值分别为0.021、0.000);血清CA125水平升高与病理分化程度、宫颈受累和盆腔淋巴结转移相关(P值分别为0.014、0.006、0.018);CEA与各临床病理特征间均无相关性(P均>0.05).血清CP2

  19. Elevated 5-hydroxymethylcytosine in the Engrailed-2 (EN-2) promoter is associated with increased gene expression and decreased MeCP2 binding in autism cerebellum.

    Science.gov (United States)

    James, S J; Shpyleva, S; Melnyk, S; Pavliv, O; Pogribny, I P

    2014-10-07

    Epigenetic mechanisms regulate programmed gene expression during prenatal neurogenesis and serve as a mediator between genetics and environment in postnatal life. The recent discovery of 5-hydroxymethylcytosine (5-hmC), with highest concentration in the brain, has added a new dimension to epigenetic regulation of neurogenesis and the development of complex behavior disorders. Here, we take a candidate gene approach to define the role 5-hmC in Engrailed-2 (EN-2) gene expression in the autism cerebellum. The EN-2 homeobox transcription factor, previously implicated in autism, is essential for normal cerebellar patterning and development. We previously reported EN-2 overexpression associated with promoter DNA hypermethylation in the autism cerebellum but because traditional DNA methylation methodology cannot distinguish 5-methylcytosine (5-mC) from 5-hmC, we now extend our investigation by quantifying global and gene-specific 5-mC and 5-hmC. Globally, 5-hmC was significantly increased in the autism cerebellum and accompanied by increases in the expression of de novo methyltransferases DNMT3A and DNMT3B, ten-eleven translocase genes TET1 and TET3, and in 8-oxo-deoxyguanosine (8-oxo-dG) content, a marker of oxidative DNA damage. Within the EN-2 promoter, there was a significant positive correlation between 5-hmC content and EN-2 gene expression. Based on reports of reduced MeCP2 affinity for 5-hmC, MeCP2 binding studies in the EN-2 promoter revealed a significant decrease in repressive MeCP2 binding that may contribute to the aberrant overexpression of EN-2. Because normal cerebellar development depends on perinatal EN-2 downregulation, the sustained postnatal overexpression suggests that a critical window of cerebellar development may have been missed in some individuals with autism with downstream developmental consequences. Epigenetic regulation of the programmed on-off switches in gene expression that occur at birth and during early brain development warrants

  20. The transiting exoplanet CoRoT-11b and its peculiar tidal evolution

    Directory of Open Access Journals (Sweden)

    Damiani C.

    2011-02-01

    Full Text Available CoRoT-11b is a fairly massive hot-Jupiter (Mp = 2.33 ± 0.34 MJup in a 3 days orbit around a F6 V star with an age of 2 ± 1 Gyr. The relatively high projected rotational velocity of the star (v sin i⋆ = 40 ± 5 km/s places CoRoT-11 among the most rapidly rotating planet hosting stars discovered so far. Assuming that the star is seen equator-on, the v sin i⋆ and the star radius (R∗ = 1.37±0.03 R⊙ translate into a stellar rotation period of 1.73±0.26 days. This peculiar planet/star configuration offers an unique opportunity to study the tidal evolution of the system. Owing to the strong tidal interaction, the planet would have moved outwards, from a starting semi-major axis corresponding to an orbital period almost synchronized with the stellar rotation. We found that the present value of the tidal quality factor Q′s could be measured by a timing of the mid-epoch of the transits to be observed with an accuracy of about 0.5 − 1 seconds over a time baseline of about 25 years.

  1. The GTC exoplanet transit spectroscopy survey. IV.: No asymmetries in the transit of Corot-29b

    CERN Document Server

    Palle, E; Alonso, R; Nowak, G; Deeg, H; Cabrera, J; Murgas, F; Parviainen, H; Nortmann, L; Hoyer, S; Prieto-Arranz, J; Nespral, D; Lavers, A Cabrera; Iro, N

    2016-01-01

    Context. The launch of the exoplanet space missions obtaining exquisite photometry from space has resulted in the discovery of thousands of planetary systems with very different physical properties and architectures. Among them, the exoplanet CoRoT-29b was identified in the light curves the mission obtained in summer 2011, and presented an asymmetric transit light curve, which was tentatively explained via the effects of gravity darkening. Aims. Transits of CoRoT-29b are measured with precision photometry, to characterize the reported asymmetry in their transit shape. Methods. Using the OSIRIS spectrograph at the 10-m GTC telescope, we perform spectro-photometric di?erential observations, which allow us to both calculate a high-accuracy photometric light curve, and a study of the color-dependence of the transit. Results. After careful data analysis, we find that the previously reported asymmetry is not present in either of two transits, observed in July 2014 and July 2015 with high photometric precisions of 3...

  2. Determining the Co-Rotation Radius of Nearby Spiral Galaxies Using Spiral Arm Overlays

    Science.gov (United States)

    Shameer Abdeen, Mohamed; Kennefick, Daniel; Kennefick, Julia D.; Pour Imani, Hamed; Shields, Douglas W.; Eufrasio, Rafael; Berlanga Medina, Jazmin; Monson, Erik

    2017-01-01

    Density wave theory, originally proposed by C.C. Lin and Frank Shu (Lin & Shu 1964), views the spiral arm structures in spiral galaxies as density waves that propagates through the galactic disk. Resonances within orbits create standing wave patterns of density waves that we observe as spiral arms. The theory predicts the existence of a radius known as the co-rotation radius in which the spiral arm pattern speed matches the velocities of the stars within the disk. We introduce a novel way of determining the co-rotation radius, based on an image overlaying technique, which involves tracing the arms of spiral galaxies on images observed from different wavelengths. For the purpose of this study, 12 nearby galaxies were analyzed from four different wavelengths using pitch angle measurements from a previous study (Hamed et al. 2016). We used optical wavelength images (B-Band,440 nm), two infrared wavelength (Infrared; 3.6 µm and 8 µm) Spitzer Space Telescope images and ultraviolet images from GALEX. The results were verified by checking against results compiled from the literature.

  3. A novel method to bracket the corotation radius in galaxy discs: vertex deviation maps

    Science.gov (United States)

    Roca-Fàbrega, Santi; Antoja, Teresa; Figueras, Francesca; Valenzuela, Octavio; Romero-Gómez, Mercè; Pichardo, Bárbara

    2014-05-01

    We map the kinematics of stars in simulated galaxy discs with spiral arms using the velocity ellipsoid vertex deviation (l_v). We use test particle simulations, and for the first time, fully self-consistent high-resolution N-body models. We compare our maps with the tight winding approximation model analytical predictions. We see that for all barred models, spiral arms rotate closely to a rigid body manner and the vertex deviation values correlate with the density peak's position bounded by overdense and underdense regions. In such cases, vertex deviation sign changes from negative to positive when crossing the spiral arms in the direction of disc rotation, in regions where the spiral arms are in between corotation radius (CR) and the Outer Lindblad Resonance (OLR). By contrast, when the arm sections are inside the CR and outside the OLR, l_v changes from negative to positive. We propose that measurements of the vertex deviation's pattern can be used to trace the position of the main resonances of the spiral arms. We propose that this technique might exploit future data from Gaia and APO Galactic Evolution Experiment (APOGEE) surveys. For unbarred N-body simulations with spiral arms corotating with disc material at all radii, our analysis suggests that no clear correlation exists between l_v and density structures.

  4. A NURBS-based finite element model applied to geometrically nonlinear elastodynamics using a corotational approach

    KAUST Repository

    Espath, L. F R

    2015-02-03

    A numerical model to deal with nonlinear elastodynamics involving large rotations within the framework of the finite element based on NURBS (Non-Uniform Rational B-Spline) basis is presented. A comprehensive kinematical description using a corotational approach and an orthogonal tensor given by the exact polar decomposition is adopted. The state equation is written in terms of corotational variables according to the hypoelastic theory, relating the Jaumann derivative of the Cauchy stress to the Eulerian strain rate.The generalized-α method (Gα) method and Generalized Energy-Momentum Method with an additional parameter (GEMM+ξ) are employed in order to obtain a stable and controllable dissipative time-stepping scheme with algorithmic conservative properties for nonlinear dynamic analyses.The main contribution is to show that the energy-momentum conservation properties and numerical stability may be improved once a NURBS-based FEM in the spatial discretization is used. Also it is shown that high continuity can postpone the numerical instability when GEMM+ξ with consistent mass is employed; likewise, increasing the continuity class yields a decrease in the numerical dissipation. A parametric study is carried out in order to show the stability and energy budget in terms of several properties such as continuity class, spectral radius and lumped as well as consistent mass matrices.

  5. The intimate relation between the low T/W instability and the co-rotation point

    CERN Document Server

    Passamonti, Andrea

    2014-01-01

    We study the low T/W instability associated with the f-mode of differentially rotating stars. Our stellar models are described by a polytropic equation of state and the rotation profile is given by the standard j-constant law. The properties of the relevant oscillation modes, including the instability growth time, are determined from time evolutions of the linearised dynamical equations in Newtonian gravity. In order to analyse the instability we monitor also the canonical energy and angular momentum. Our results demonstrate that the l=m=2 f-mode becomes unstable as soon as a co-rotation point develops inside the star (i.e. whenever there is a point where the mode's pattern speed matches the bulk angular velocity). Considering various degrees of differential rotation, we show that the instability grows faster deep inside the co-rotation region and deduce an empirical relation that correlates the mode frequency and the star's parameters, which captures the main features of the l=m=2 f-mode growth time. This fu...

  6. Galactic Archaeology with asteroseismology and spectroscopy: Red giants observed by CoRoT and APOGEE

    CERN Document Server

    Anders, F; Rodrigues, T S; Miglio, A; Montalbán, J; Mosser, B; Girardi, L; Valentini, M; Noels, A; Morel, T; Johnson, J A; Schultheis, M; Baudin, F; Peralta, R de Assis; Hekker, S; Themeßl, N; Kallinger, T; García, R A; Mathur, S; Baglin, A; Santiago, B X; Martig, M; Minchev, I; Steinmetz, M; da Costa, L N; Maia, M A G; Prieto, C Allende; Cunha, K; Beers, T C; Epstein, C; Pérez, A E García; García-Hernández, D A; Harding, P; Holtzman, J; Majewski, S R; Mészáros, Sz; Nidever, D; Pan, K; Pinsonneault, M; Schiavon, R P; Schneider, D P; Shetrone, M D; Stassun, K; Zamora, O; Zasowski, G

    2016-01-01

    With the advent of the space missions CoRoT and Kepler, it has become feasible to determine precise asteroseismic masses and ages for large samples of red-giant stars. In this paper, we present the CoRoGEE dataset -- obtained from CoRoT lightcurves for 606 red giant stars in two fields of the Galactic disc which have been co-observed for an ancillary project of APOGEE. We have used the Bayesian parameter estimation code PARAM to calculate distances, extinctions, masses, and ages for these stars in a homogeneous analysis, resulting in relative statistical uncertainties of $\\sim2\\%$ in distance, $\\sim4\\%$ in radius, $\\sim9\\%$ in mass and $\\sim25\\%$ in age. We also assess systematic age uncertainties due to different input physics and mass loss. We discuss the correlation between ages and chemical abundance patterns of field stars over a large radial range of the Milky Way's disc (5 kpc $

  7. Search for Exomoons and Rings with Kepler and CoRoT

    Science.gov (United States)

    Moretto Tusnski, Luis Ricardo; Silva Valio, Adriana

    2015-08-01

    After almost 20 years since the first exoplanet discoveries, new techniques have been developed and high precision has been achieved, which lead to a large number of small planets detected. Recently, some researchers are trying to detect exomoons: moons around exoplanets. Some methods have been proposed and studied, and the most likely to lead to a discovery is the planetary transit technique. Exomoons cause two types of effects in the planet transit light curve: photometric signatures and transit timing effects. Despite the searches and methods proposed, so far no moon has been found around exoplanets. One reason for this is the small number of searches been conducted. In this work, we present an independent serch project called PSER - Photometric Search for Exomoons and Rings. As the name states, this project looks for exomoons and exorings in Kepler and CoRoT lightcurves. To do so, we developed a program to look for exomoons signals automatically, using MCMC to fit the lightcurves. We started our search with Kepler and CoRoT confirmed single planets. After that, we will also look in Kepler Planetary Candidates. So far, no signal has been found.

  8. On the rotation period distribution of CoRoT and Kepler Sun-like stars

    CERN Document Server

    Leao, I C; Lopes, C E Ferreira; Neves, V; Valcarce, A A R; de Oliveira, L L A; da Silva, D Freire; de Freitas, D B; Martins, B L Canto; Janot-Pacheco, E; Baglin, A; De Medeiros, J R

    2015-01-01

    We study the distribution of the photometric rotation period (Prot), which is a direct measurement of the surface rotation at active latitudes, for three subsamples of Sun-like stars: one from CoRoT data and two from Kepler data. We identify the main populations of these samples and interpret their main biases particularly for a comparison with the solar Prot. Prot and variability amplitude (A) measurements were obtained from public CoRoT and Kepler catalogs, which were combined with public data of physical parameters. Because these samples are subject to selection effects, we computed synthetic samples with simulated biases to compare with observations, particularly around the Sun's HR-diagram location. Theoretical grids and empirical relations were used to combine physical parameters with Prot and A. Biases were simulated by performing cutoffs on the physical and rotational parameters in the same way as in each observed sample. A crucial cutoff is related with the detectability of the rotational modulation,...

  9. A localised co-rotating auroral absorption event observed near noon using imaging riometer and EISCAT

    Directory of Open Access Journals (Sweden)

    P. N. Collis

    Full Text Available An isolated region of energetic electron precipitation observed near local noon in the auroral zone has been investigated using imaging riometer (IRIS and incoherent-scatter radar (EISCAT techniques. IRIS revealed that the absorption event was essentially co-rotating with the Earth for about 2 h. The spatial and temporal variations in D-region electron density seen by EISCAT were able to be interpreted within a proper context when compared with the IRIS data. EISCAT detected significant increases in electron density at altitudes as low as 65 km as the event drifted through the radar beam. The altitude distribution of incremental radio absorption revealed that more than half of the absorption occurred below 75 km, with a maximum of 67 km. The energy spectrum of the precipitating electrons was highly uniform throughout the event, and could be described analytically by the sum of three exponential distributions with characteristic energies of 6, 70 and 250 keV. A profile of effective recombination coefficient that resulted in self-consistent agreement between observed electron desities and those inferred from an inversion procedure has been deduced. The observations suggest a co-rotating magnetospheric source region on closed dayside field lines. However, a mechanism is required that can sustain such hard precipitation for the relatively long duration of the event.

  10. Interacting galaxies: co-rotating and counter-rotating systems with tidal tails

    CERN Document Server

    Mesa, Valeria; Alonso, Sol; Coldwell, Georgina; Lambas, Diego G

    2013-01-01

    We analyse interacting galaxy pairs with evidence of tidal features in the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). The pairs were selected within $z<0.1$ by requiring a projected separation $r_p < 50 \\kpc$ and relative radial velocity $\\Delta V < 500 \\kms$. We complete spectroscopic pairs using galaxies with photometric redshifts considering $\\Delta V_{phot} < 6800 \\kms$, taking into account the mean photometric redshift uncertainty. We classify by visual inspection pairs of spirals into co-rotating and counter-rotating systems. For a subsample of non-AGN galaxies, counter-rotating pairs have larger star formation rates, and a higher fraction of young, star-forming galaxies. These effects are enhanced by restricting to $r_p < 12 \\kpc$. The distributions of $C$, $D_n(4000)$ and $(M_u-M_r)$ for AGN galaxies show that counter-rotating hosts have bluer colours and younger stellar population than the co-rotating galaxies although the relative fractions of Seyfert, Liner, Composite and Am...

  11. Constraints on the exosphere of CoRoT-7b

    CERN Document Server

    Guenther, E W; Erikson, A; Fridlund, M; Lammer, H; Mura, A; Rauer, H; Schneider, J; Tulej, M; von Paris, Ph; Wurz, P

    2010-01-01

    Context: The small radius and high density of CoRoT-7b implies that this transiting planet belongs to a different species than all transiting planets that have previously been found. Current models suggest that this is the first transiting rocky planet found outside the solar system. Given that the planet orbits a solar-like star at a distance of only 4.5 R*, it is expected that material from its surface is released which would then form an exosphere. AIMS: {Our aim is to constrain the properties of the exosphere by observing the planet in and out-of-transit. The detection of the exosphere of CoRoT-7b would for the first time allow to study the material originating from the surface of a rocky extrasolar planet. We survey the whole optical spectrum for any lines originating from the planet, particularly focusing on spectral-lines like those that have been detected in Mercury, and Io in our solar-system.} Methods: Given that it is expected that lines originating from the exosphere will be narrow, we observed Co...

  12. XX. CoRoT-20b: A very high density, high eccentricity transiting giant planet

    CERN Document Server

    Deleuil, M; Ferraz-Mello, S; Erikson, A; Bouchy, F; Havel, M; Aigrain, S; Almenara, J -M; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Bordé, P; Bruntt, H; Cabrera, J; Carpano, S; Cavarroc, C; Csizmadia, Sz; Damiani, C; Deeg, H J; Dvorak, R; Fridlund, M; Hébrard, G; Gandolfi, D; Gillon, M; Guenther, E; Guillot, T; Hatzes, A; Jorda, L; Léger, A; Lammer, H; Mazeh, T; Moutou, C; Ollivier, M; Ofir, A; Parviainen, H; Queloz, D; Rauer, H; Rodríguez, A; Rouan, D; Santerne, A; Schneider, J; Tal-Or, L; Tingley, B; Weingrill, J; Wuchterl, G

    2011-01-01

    We report the discovery by the CoRoT space mission of a new giant planet, CoRoT-20b. The planet has a mass of 4.24 +/- 0.23 MJ and a radius of 0.84 +/- 0.04 RJ. With a mean density of 8.87 +/- 1.10 g/cm^3, it is among the most compact planets known so far. Evolution models for the planet suggest a mass of heavy elements of the order of 800 ME if embedded in a central core, requiring a revision either of the planet formation models or of planet evolution and structure models. We note however that smaller amounts of heavy elements are expected from more realistic models in which they are mixed throughout the envelope. The planet orbits a G-type star with an orbital period of 9.24 days and an eccentricity of 0.56. The star's projected rotational velocity is vsini = 4.5 +/- 1.0 km/s, corresponding to a spin period of 11.5 +/- 3.1 days if its axis of rotation is perpendicular to the orbital plane. In the framework of Darwinian theories and neglecting stellar magnetic breaking, we calculate the tidal evolution of t...

  13. Semi-empirical seismic relations of A-F stars from COROT and Kepler legacy data

    Science.gov (United States)

    Moya, A.; Suárez, J. C.; García Hernández, A.; Mendoza, M. A.

    2017-10-01

    Asteroseismology is witnessing a revolution, thanks to high-precise asteroseismic space data (MOST, COROT, Kepler, BRITE) and their large ground-based follow-up programs. Those instruments have provided an unprecedented large amount of information, which allows us to scrutinize its statistical properties in the quest for hidden relations among pulsational and/or physical observables. This approach might be particularly useful for stars whose pulsation content is difficult to interpret. This is the case of intermediate-mass classical pulsating stars (i.e. γ Dor, δ Scuti, hybrids) for which current theories do not properly predict the observed oscillation spectra. Here, we establish a first step in finding such hidden relations from data mining techniques for these stars. We searched for those hidden relations in a sample of δ Scuti and hybrid stars observed by COROT and Kepler (74 and 153, respectively). No significant correlations between pairs of observables were found. However, two statistically significant correlations emerged from multivariable correlations in the observed seismic data, which describe the total number of observed frequencies and the largest one, respectively. Moreover, three different sets of stars were found to cluster according to their frequency density distribution. Such sets are in apparent agreement with the asteroseismic properties commonly accepted for A-F pulsating stars.

  14. Off-the-energy-shell pp scattering in the exclusive proton knockout 12C(p,2p) reaction at 392 MeV

    CERN Document Server

    Sumi, T T

    2008-01-01

    The triple differential cross section (TDX) for the 12C(p,2p) proton knockout reaction from the 1p3/2 single-particle state measured at 392 MeV is investigated by nonrelativistic distorted wave impulse approximation (DWIA) with accurate treatment of the kinematics of the colliding two protons and effects of in-medium modification to the matrix elements of the proton-proton (pp) effective interaction. Some simplifying approximations made in previous studies with DWIA are examined. The off-the-energy-shell matrix elements of the pp effective interaction are shown to play an essential role in describing the asymmetric two peaks of the measured TDX corresponding to the kinematics in which the momentum transfer is fixed.

  15. Disruption of MeCP2 attenuates circadian rhythm in CRISPR/Cas9-based Rett syndrome model mouse.

    Science.gov (United States)

    Tsuchiya, Yoshiki; Minami, Yoichi; Umemura, Yasuhiro; Watanabe, Hitomi; Ono, Daisuke; Nakamura, Wataru; Takahashi, Tomoyuki; Honma, Sato; Kondoh, Gen; Matsuishi, Toyojiro; Yagita, Kazuhiro

    2015-12-01

    Methyl-CpG-binding protein 2 (Mecp2) is an X-linked gene encoding a methylated DNA-binding nuclear protein which regulates transcriptional activity. The mutation of MECP2 in humans is associated with Rett syndrome (RTT), a neurodevelopmental disorder. Patients with RTT frequently show abnormal sleep patterns and sleep-associated problems, in addition to autistic symptoms, raising the possibility of circadian clock dysfunction in RTT. In this study, we investigated circadian clock function in Mecp2-deficient mice. We successfully generated both male and female Mecp2-deficient mice on the wild-type C57BL/6 background and PER2(Luciferase) (PER2(Luc)) knock-in background using the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system. Generated Mecp2-deficient mice recapitulated reduced activity in mouse models of RTT, and their activity rhythms were diminished in constant dark conditions. Furthermore, real-time bioluminescence imaging showed that the amplitude of PER2(Luc)-driven circadian oscillation was significantly attenuated in Mecp2-deficient SCN neurons. On the other hand, in vitro circadian rhythm development assay using Mecp2-deficient mouse embryonic stem cells (ESCs) did not show amplitude changes of PER2(Luc) bioluminescence rhythms. Together, these results show that Mecp2 deficiency abrogates the circadian pacemaking ability of the SCN, which may be a therapeutic target to treat the sleep problems of patients with RTT.

  16. Transiting exoplanets from the CoRoT space missionXIX. CoRoT-19b: A low density planet orbiting an old inactive F9V-star

    CERN Document Server

    Guenther, E W; Gazzano, J -C; Mazeh, T; Rouan, D; Gibson, N; Csizmadia, Sz; Aigrain, S; Alonso, R; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Bruntt, H; Cabrera, J; Carone, L; Carpano, S; Cavarroc, C; Deeg, H J; Deleuil, M; Dreizler, S; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gillon, M; Guillot, T; Hatzes, A; Havel, M; Hebrard, G; Jehin, E; Jorda, L; Lammer, H; Leger, A; Moutou, C; Nortmann, L; Ollivier, M; Ofir, A; Pasternacki, Th; Paetzold, M; Parviainen, H; Queloz, D; Rauer, H; Samuel, B; Santerne, A; Schneider, J; Tal-Or, L; Tingley, B; Weingrill, J; Wuchterl, G

    2011-01-01

    Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. The CoRoT space mission allows us to achieve a very high photometric accuracy. By combining CoRoT data with high-precision radial velocity measurements, we derive precise planetary radii and masses. We report the discovery of CoRoT-19b, a gas-giant planet transiting an old, inactive F9V-type star with a period of four days. After excluding alternative physical configurations mimicking a planetary transit signal, we determine the radius and mass of the planet by combining CoRoT photometry with high-resolution spectroscopy obtained with the echelle spectrographs SOPHIE, HARPS, FIES, and SANDIFORD. To improve the precision of its ephemeris and the epoch, we observed additional transits with the TRAPPIST and Euler telescopes. Using HARPS spectra obtained during the transit, we then determine the projected angle between the spin of the star and the orbi...

  17. Silica-supported (nBuCp)2ZrCl2: Effect of catalyst active center distribution on ethylene-1-hexene copolymerization

    KAUST Repository

    Atiqullah, Muhammad

    2013-08-12

    Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts-silica/MAO/(nBuCp)2ZrCl2 (Catalyst 1) and silica/nBuSnCl3/MAO/(nBuCp)2ZrCl2 (Catalyst 2), where MAO is methylaluminoxane-were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene-1-hexene Copolymer 1 and Copolymer 2, respectively. Fouling-free copolymerization, catalyst kinetic stability and production of free-flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self-nucleation and annealing experiments, as well as by an extended X-ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO-pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co-monomer effect-both by 1-hexene-were common. Each copolymer demonstrated vinyl, vinylidene and trans-vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction

  18. BEER analysis of Kepler and CoRoT light curves. III. Spectroscopic confirmation of seventy new beaming binaries discovered in CoRoT lightcurves

    CERN Document Server

    Tal-Or, Lev; Mazeh, Tsevi

    2015-01-01

    (abridged for arXiv) The BEER algorithm, introduced by Faigler & Mazeh (2011), searches stellar lightcurves for the BEaming, Ellipsoidal, and Reflection photometric modulations caused by a short-period companion. Applying the search to the first five long-run center CoRoT fields, we identified $481$ non-eclipsing candidates with periodic flux amplitudes of $0.5-87$ mmag. Optimizing the Anglo-Australian-Telescope pointing coordinates and the AAOmega fiber-allocations with dedicated softwares, we acquired $6-7$ medium-resolution spectra of $281$ candidates in a seven-night campaign. Analysis of the red-arm AAOmega spectra, which covered the range of $8342-8842$ \\AA{}, yielded a radial-velocity precision of $\\sim1$ km/s. Spectra containing lines of more than one star were analyzed with TODCOR$-$the two-dimensional correlation algorithm. The measured radial velocities confirmed the binarity of seventy of the BEER candidates$-45$ single-line binaries, $18$ double-line binaries, and $7$ diluted binaries. We sho...

  19. Three-Dimensional Flow Modeling of a Self-wiping Corotating Twin-Screw Extruder. Part II : The Kneading Section

    NARCIS (Netherlands)

    Wal, D.J. van der; Goffart, D.; Klomp, E.M.; Hoogstraten, H.W.; Janssen, L.P.B.M.

    1996-01-01

    Three-dimensional flow simulations of kneading elements in an intermeshing corotating twin-screw extruder are performed by solving the Navier Stokes equations with a finite element package, Sepran. Instead of using the whole geometry of the 8-shaped barrel a simplified geometry is used, representing

  20. THE SELF-WIPING CO-ROTATING TWIN-SCREW EXTRUDER AS A POLYMERIZATION REACTOR FOR METHACRYLATES

    NARCIS (Netherlands)

    Jongbloed, H.A.; Kiewiet, J.A.; van Dijk, J.H.; Janssen, L.P.B.M.

    1995-01-01

    The self-wiping co-rotating twin-screw extruder was studied as a reactor for two polymerizations in bulk: the homopolymerization of n-butylmethacrylate and the copolymerization of n-butylmethacrylate with 2-hydroxypropylmethacrylate. The influence of the extrusion parameters on the product was analy

  1. On a role of corotation radius in the low $T/W$ dynamical instability of differentially rotating stars

    CERN Document Server

    Yoshida, Shin'ichirou

    2016-01-01

    We investigate the nature of so-called low $T/W$ dynamical instability in a differentially rotating star by focusing on the role played by the corotation radius of the unstable oscillation modes. An one dimensional model of linear perturbation, which neglects dependence of variables on the coordinate along the rotational axis of the star, is solved to obtain stable and unstable eigenmodes. A linear eigenmode having a corotation radius, at which azimuthal pattern speed of the mode coincides with the stellar angular velocity, is categorized to either a complex (growing or damping) mode or a purely real mode belonging to a continuous spectrum of frequency. We compute canonical angular momentum and its flux to study eigenmodes with corotation radius. In a dynamically unstable mode, sound wave transports its angular momentum in such a way that the absolute value of the angular momentum is increased on both sides of the corotation radius. We further evaluate growth of amplitude of reflected sound wave incident to a...

  2. Fundamental properties of stars using asteroseismology from Kepler and CoRoT and interferometry from the CHARA Array

    DEFF Research Database (Denmark)

    Huber, D.; Ireland, M.J.; Bedding, T.R.;

    2012-01-01

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combinin...

  3. Identifying the "true" radius of the hot sub-Neptune CoRoT-24b by mass loss modelling

    CERN Document Server

    Lammer, H; Fossati, L; Juvan, I; Odert, P; Cubillos, P E; Guenther, E; Kislyakova, K G; Johnstone, C P; Lueftinger, T; Guedel, M

    2016-01-01

    For the hot exoplanets CoRoT-24b and CoRoT-24c, observations have provided transit radii R$_{\\rm T}$ of 3.7$\\pm$0.4 R$_{\\oplus}$ and 4.9$\\pm$0.5 R$_{\\oplus}$, and masses of $\\le$5.7 M$_{\\oplus}$ and 28$\\pm$11 M$_{\\oplus}$, respectively. We study their upper atmosphere structure and escape applying an hydrodynamic model. Assuming R$_{\\rm T} \\approx$ R$_{\\rm PL}$, where R$_{\\rm PL}$ is the planetary radius at the pressure of 100 mbar, we obtained for CoRoT-24b unrealistically high thermally-driven hydrodynamic escape rates. This is due to the planet's high temperature and low gravity, independent of the stellar EUV flux. Such high escape rates could last only for $<$100 Myr, while R$_{\\rm PL}$ shrinks till the escape rate becomes less than or equal to the maximum possible EUV-driven escape rate. For CoRoT-24b, R$_{\\rm PL}$ must be therefore located at $\\approx 1.9-2.2$ R$_{\\oplus}$ and high altitude hazes/clouds possibly extinct the light at R$_{\\rm T}$. Our analysis constraints also the planet's mass to be ...

  4. Clinical value of serum CA19-9,CA125 and CP2 in mucinous ovarian tumor:a retrospective study of 273 patients%CA19-9、CA125和CP2在卵巢黏液性肿瘤诊断和监测中的价值

    Institute of Scientific and Technical Information of China (English)

    董丽; 崔恒; 李小平; 孙丽芳; 昌晓红; 梁旭东; 祝洪澜

    2008-01-01

    目的 探讨血清肿瘤标志物CA19-9、CA125及CP2在卵巢黏液性肿瘤诊断和监测中的价值.方法 对北京大学人民医院1999年1月至2007年6月间收治的273例卵巢肿瘤患者的临床资料进行回顾性分析,探讨血清肿瘤标志物CA19-9、CA125及CP2在50例卵巢黏液性肿瘤诊断和监测中的价值,并与223例卵巢非黏液性肿瘤进行比较.结果 (1)卵巢黏液性肿瘤中,CA19-9的曲线下面积最大(为0.95),其次是CA125(为0.90);而卵巢非黏液肿瘤中,CA125和CP2的曲线下面积最大(均为0.90).(2)卵巢黏液性肿瘤患者联合检测CA19-9和CA125时,其敏感度(93.8%)较单项检测(CA19-9和CA125分别为75.0%和66.7%)明显提高(P<0.05),而特异度(分别为86.1%、86.6%和90.2%)无明显变化(P>0.05).卵巢非黏液性肿瘤患者联合检测CA125和CP2时的敏感度(85.0%),较CP2(70.6%)单项检测明显提高,差异有统计学意义(P<0.05);较CA125(80.7%)单项检测虽有提高,但差异无统计学意义(P>0.05);3者的特异度(分别为90.2%、88.5%和93.9%)比较,差异无统计学意义(P>0.05).(3)82例卵巢恶性肿瘤术前血清肿瘤标志物阳性患者中,可行满意的肿瘤细胞减灭术患者[70%(57/82)]的血清肿瘤标志物于术后2个月内降为正常的百分率高于未能行满意肿瘤细胞减灭术者(分别为75%和28%),差异有统计学意义(P<0.05);且其术后血清肿瘤标志物再次上升的平均时间延长(分别为18.2和16.4个月),但差异无统计学意义(P>0.05);复发率(分别为35%和56%)及死亡率(分别为14%和32%)降低,差异有统计学意义(P<0.05).20例术前血清肿瘤标志物阴性患者均可行满意的肿瘤细胞减灭术,其中复发患者仅2例(10%).(4)卵巢黏液性肿瘤患者术后复发时多为血清CA19-9水平上升,而卵巢非黏液性肿瘤术后复发时主要为血清CA125水平上升,部分患者血清CP2水平也上升.(5)术前血清肿瘤标志物阳性患者较阴性患者

  5. 法国CP1-CP2系列核电机组安全重要设备分级的经验反馈%Experience Feedback of the Classification for the Important Equipment to Safety in the Plant Series CP1-CP2 of France

    Institute of Scientific and Technical Information of China (English)

    耿文行; 赵月扬

    2007-01-01

    本文介绍了在法国900MWeCP1-CP2系列核电机组定期安全审查中制定安全重要设备清单时确定安全分级所用的原则和方法.除了对分级清单增补机械设备和电气设备项目外,还引入了安全重要的非安全级(IPS-NC)设备的概念、原则和有关要求.

  6. Influence of the Earth s Corotation Field on the Atmospheric Electricity: Latitudinal Variation and Response to the Solar Activity

    Science.gov (United States)

    Dumin, Y.

    Influence of the magnetospheric convection field on the atmospheric electricity is widely studied, both theoretically and experimentally, from the early 1970s. On the other hand, a considerably less attention was paid to the effects of plasmaspheric corotation field, since it was usually believed that the electric field of corotation of the solid Earth is fitted smoothly to the corotation field of plasmasphere, so that no potential difference is formed between them in the lower atmosphere. A conjecture on the important role of corotation field in the global atmospheric-electric circuit was done a few years ago in [P.A. Bespalov, Yu.V. Chugunov, J. Atmos. Terr. Phys., 1996, v.58, p.601] and several subsequent works. Unfortunately, because of using an oversimplified model of plasmasphere (in the form of a spherically-symmetric envelope with isotropic conductivity and rigid-body rotation), no reliable numerical estimates were derived, and no comparison with experimental distributions of the atmospheric electric field could be conducted. The main aim of the present report is to study the corotation effects in the framework of a considerably more realistic analytical model, where conductivity of the plasmasphere is strongly anisotropic, and the magnetic field lines are substantially distorted (stretched to "infinity") in the polar regions. Escape of polarization electric charges along the distorted field lines results in appreciable decrease (by 10-15 V/m) in the average atmospheric electric field at high latitudes. Such phenomenon was experimentally discovered as early as the International Geophysical Year (1957-1958) but was not quantitatively explained by now. Yet another interesting effect following from our model is changing the high-latitude electric field due to variations in the degree of distortion of the magnetic field lines at different levels of the solar activity. These transient changes in the atmospheric electricity should be symmetric about the noon

  7. Anisotropy of >35 keV ions in corotating particle events at 1 AU

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, I.G. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)

    1985-02-01

    The anisotropy of 35-1000 keV ions in two corotating particle events associated with high-speed solar wind streams at 1 AU is examined in terms of the diffusion-convection propagation model using data from the Energetic Proton Anisotropy Spectrometer on ISEE-3. The calculated diffusive anisotropy in the solar wind frame is found to be sunward and closely field-aligned, with a nearly energy-independent magnitude of approx. 40%. For one stream, using the Voyager 2 data of Decker et al.(1981), a positive gradient of approx. 100%/AU is found for >approx. 50 keV ions between 1 and 4 AU. The observations do not appear to support the scatter-free propagation model and indicate that ions with energies as low as a few tens of keV may be in diffusive equilibrium with the solar wind in this class of events.

  8. Corotational formulation for 3d solids. An analysis of geometrically nonlinear foam deformation

    CERN Document Server

    Kaczmarczyk, Łukasz; Pearce, Chris J

    2011-01-01

    This paper presents theory for the Lagrange co-rotational (CR) formulation of finite elements in the geometrically nonlinear analysis of 3D structures. In this paper strains are assumed to be small while the magnitude of rotations from the reference configuration is not restricted. A new best fit rotator and consistent spin filter are derived. Lagrange CR formulation is applied with Hybrid Trefftz Stress elements, although presented methodology can be applied to arbitrary problem formulation and discretization technique, f.e. finite volume methods and lattice models, discreet element methods. Efficiency of CR formulation can be utilized in post-buckling stability analysis, damage and fracture mechanics, modelling of dynamic fragmentation of bodies made from quasi-brittle materials, solid fluid interactions and analysis of post-stressed structures, discreet body dynamics.

  9. CONSTITUTIVE EQUATION OF CO-ROTATIONAL DERIVATIVE TYPE FOR ANISOTROPIC-VISCOELASTIC FLUID

    Institute of Scientific and Technical Information of China (English)

    HAN Shifang

    2004-01-01

    A constitutive equation theory of Oldroyd fluid B type, i.e. the co-rotational derivative type, is developed for the anisotropic-viscoelastic fluid of liquid crystalline (LC) polymer. Analyzing the influence of the orientational motion on the material behavior and neglecting the influence, the constitutive equation is applied to a simple case for the hydrodynamic motion when the orientational contribution is neglected in it and the anisotropic relaxation, retardation times and anisotropic viscosities are introduced to describe the macroscopic behavior of the anisotropic LC polymer fluid. Using the equation for the shear flow of LC polymer fluid, the analytical expressions of the apparent viscosity and the normal stress differences are given which are in a good agreement with the experimental results of Baek et al. For the fiber spinning flow of the fluid, the analytical expression of the extensional viscosity is given.

  10. Physical State of the Deep Interior of the CoRoT-7b Exoplanet

    CERN Document Server

    Wagner, F W; Rückriemen, T; Rauer, H

    2011-01-01

    The present study takes the CoRoT-7b exoplanet as an analogue for massive terrestrial planets to investigate conditions, under which intrinsic magnetic fields could be sustained in liquid cores. We examine the effect of depth-dependent transport parameters (e.g., activation volume of mantle rock) on a planet's thermal structure and the related heat flux across the core mantle boundary. For terrestrial planets more massive than the Earth, our calculations suggest that a substantial part of the lowermost mantle is in a sluggish convective regime, primarily due to pressure effects on viscosity. Hence, we find substantially higher core temperatures than previously reported from parameterized convection models. We also discuss the effect of melting point depression in the presence of impurities (e.g., sulfur) in iron-rich cores and compare corresponding melting relations to the calculated thermal structure. Since impurity effects become less important at the elevated pressure and temperature conditions prevalent i...

  11. Large Amplitude IMF Fluctuations in Corotating Interaction Regions: Ulysses at Midlatitudes

    Science.gov (United States)

    Tsurutani, Bruce T.; Ho, Christian M.; Arballo, John K.; Goldstein, Bruce E.; Balogh, Andre

    1995-01-01

    Corotating Interaction Regions (CIRs), formed by high-speed corotating streams interacting with slow speed streams, have been examined from -20 deg to -36 deg heliolatitudes. The high-speed streams emanate from a polar coronal hole that Ulysses eventually becomes fully embedded in as it travels towards the south pole. We find that the trailing portion of the CIR, from the interface surface (IF) to the reverse shock (RS), contains both large amplitude transverse fluctuations and magnitude fluctuations. Similar fluctuations have been previously noted to exist within CIRs detected in the ecliptic plane, but their existence has not been explained. The normalized magnetic field component variances within this portion of the CIR and in the trailing high-speed stream are approximately the same, indicating that the fluctuations in the CIR are compressed Alfven waves. Mirror mode structures with lower intensities are also observed in the trailing portion of the CIR, presumably generated from a local instability driven by free energy associated with compression of the high-speed solar wind plasma. The mixture of these two modes (compressed Alfven waves and mirror modes) plus other modes generated by three wave processes (wave-shock interactions) lead to a lower Alfvenicity within the trailing portion of the CfR than in the high-speed stream proper. The results presented in this paper suggest a mechanism for generation of large amplitude B(sub z) fluctuations within CIRS. Such phenomena have been noted to be responsible for the generation of moderate geomagnetic storms during the declining phase of the solar cycle.

  12. The turbulent flow in an enclosed corotating disk pair: axisymmetric numerical simulation and Reynolds stress modelling

    Energy Technology Data Exchange (ETDEWEB)

    Randriamampianina, A.; Schiestel, R. [UMR CNRS, Marseille (France). Institut de Recherche sur les Phenomenes; Wilson, M. [University of Bath (United Kingdom). Dept. of Mechanical Engineering

    2004-12-01

    We present axisymmetric numerical simulation and modelling of the turbulent flow between corotating disks with a stationary outer casing, the enclosed corotating disk pair configuration. This follows previous work on laminar flow for an identical geometry defined by a gap ratio G=0.6 (=s/(b-a)) and a/b=0.5, where a and b are the inner and outer radii, and s is the inter-disk distance [J. Fluid Mech. 434 (2001) 39]. The rotation rate considered in the present case is equivalent to Re=1.46 x 10{sup 5}, where Re (={omega}b{sup 2}/{nu}) is the rotational Reynolds number. This corresponds to a value at which mean flow measurements have been obtained for the same configuration [Flow in a rotating cavity with a peripheral inlet and outlet of cooling air, in: ASME Int. Gas Turbine and Aeroengine Cong., paper 96-GT-309, Birmingham]. In computed laminar regimes, it was found previously for this aspect ratio that the flow structure is first characterized by a shift-and-reflect symmetry at lower values of Re before bifurcating to symmetry breaking at higher rotation rates. For the rotation rate under consideration here, the flow is turbulent and shows an unsteady behaviour in the mean, characterized by flapping of the flow between the two disks, inducing symmetry breaking with respect to the inter-disk midplane. Similarities are observed between the centripetal flow coming from the stationary casing and an impinging jet in a cavity. Comparisons are made between the computed results from the axisymmetric numerical simulation (ANS), a Reynolds Stress Transport Model (RSM) and the available experimental data. The RSM predictions are in close agreement with the mean flow measurements. The ANS results give a more detailed description of the flow characteristics, but suffer from the axisymmetry assumption that is not compatible with the three-dimensional turbulence. (author)

  13. The Berlin Exoplanet Search Telescope II Catalog of Variable Stars. II. Characterization of the CoRoT SRc02 field

    CERN Document Server

    Klagyivik, P; Pasternacki, T; Cabrera, J; Chini, R; Eigmüller, P; Erikson, A; Fruth, T; Kabath, P; Lemke, R; Murphy, M; Rauer, H; Titz-Weider, R

    2015-01-01

    Time-series photometry of the CoRoT field SRc02 was obtained by the Berlin Exoplanet Search Telescope II (BEST II) in 2009. The main aim was the ground based follow-up of the CoRoT field in order to detect variable stars with better spatial resolution than what can be achieved with the CoRoT space telescope. A total of 1,846 variable stars were detected, of which only 30 have been previously known. For nine eclipsing binaries the stellar parameters were determined by modeling their light curve.

  14. Effects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviors

    KAUST Repository

    Atiqullah, Muhammad

    2013-07-10

    Two catalysts, denoted as catalyst 1 [silica/MAO/(nBuCp) 2ZrCl2] and catalyst 2 [silica/nBuSnCl 3/MAO/(nBuCp)2ZrCl2] were synthesized and subsequently used to prepare, without separate feeding of methylaluminoxane (MAO), ethylene homopolymer 1 and homopolymer 2, respectively, and ethylene-1-hexene copolymer 1 and copolymer 2, respectively. Gel permeation chromatography (GPC), Crystaf, differential scanning calorimetry (DSC) [conventional and successive self-nucleation and annealing (SSA)], and 13C nuclear magnetic resonance (NMR) polymer characterization results were used, as appropriate, to model the catalyst active-center distribution, ethylene sequence (equilibrium crystal) distribution, and lamellar thickness distribution (both continuous and discrete). Five different types of active centers were predicted in each catalyst, as corroborated by the SSA experiments and complemented by an extended X-ray absorption fine structure (EXAFS) report published in the literature. 13C NMR spectroscopy also supported this active-center multiplicity. Models combined with experiments effectively illustrated how and why the active-center distribution and the variance in the design of the supported MAO anion, having different electronic and steric effects and coordination environments, influence the concerned copolymerization mechanism and polymer properties, including inter- and intrachain compositional heterogeneity and thermal behaviors. Copolymerization occurred according to the first-order Markovian terminal model, producing fairly random copolymers with minor skewedness toward blocky character. For each copolymer, the theoretical most probable ethylene sequences, nE MPDSC-GT and n E MPNMR-Flory, as well as the weight-average lamellar thicknesses, Lwav DSC-GT and Lwav SSA DSC, were found to be comparable. To the best of our knowledge, such a match has not previously been reported. The percentage crystallinities of the homo- and copolymers increased linearly as a function of

  15. The CoRoT B-type binary HD50230: a prototypical hybrid pulsator with g-mode period and p-mode frequency spacings

    CERN Document Server

    Degroote, P; Michel, E; Briquet, M; Pápics, P I; Amado, P; Mathias, P; Poretti, E; Rainer, M; Lombaert, R; Hillen, M; Morel, T; Auvergne, M; Baglin, A; Baudin, F; Catala, C; Samadi, R

    2012-01-01

    B-type stars are promising targets for asteroseismic modelling, since their frequency spectrum is relatively simple. We deduce and summarise observational constraints for the hybrid pulsator, HD50230, earlier reported to have deviations from a uniform period spacing of its gravity modes. The combination of spectra and a high-quality light curve measured by the CoRoT satellite allow a combined approach to fix the position of HD50230 in the HR diagram. To describe the observed pulsations, classical Fourier analysis was combined with short-time Fourier transformations and frequency spacing analysis techniques. Visual spectra were used to constrain the projected rotation rate of the star and the fundamental parameters of the target. In a first approximation, the combined information was used to interpret multiplets and spacings to infer the true surface rotation rate and a rough estimate of the inclination angle. We identify HD50230 as a spectroscopic binary and characterise the two components. We detect the simu...

  16. Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers

    KAUST Repository

    Atiqullah, Muhammad

    2014-07-01

    Two different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst active center multiplicity and polymer crystallization kinetics were modeled. Five separate active center types were predicted, which matched the successive self-nucleation and annealing (SSA) peak temperatures. The predicted crystallinity well matched the differential scanning calorimetric (DSC) values for a single Avrami-Erofeev index, which ranged between 2 and 3 for the polymers experimented. The estimated apparent crystallization activation energy Ea did not vary with cooling rates, relative crystallinity α, and crystallization time or temperature. Therefore, the concept of variable/instantaneous activation energy was not found to hold. Ea linearly increased with the weight average lamellar thickness Lwav DSC-GT; and for each homopolymer, it exceeded that of the corresponding copolymer. Higher Ea, hence slower crystallization, was identified as a pre-requisite to attain higher crystallinity. Crystallization parameters were correlated to polymer backbone parameters, which are influenced by catalyst active center multiplicity. © 2013 Taiwan Institute of Chemical Engineers.

  17. Synthesis, structure, and magnetic characterization of a hysteretic charge-transfer salt metamagnet, decamethylferrocenium 2,3-dicyano-1,4-naphthoquinonide, [Fe(Cp*)2][DCNQ].

    Science.gov (United States)

    Yee, G T; Whitton, M J; Sommer, R D; Frommen, C M; Reiff, W M

    2000-05-01

    The synthesis and single-crystal structure of a new one-to-one charge-transfer salt, derived from decamethylferrocene and 2,3-dicyano-1,4-naphthoquinone, are described. [Fe(Cp*)2][DCNQ] crystallizes in the orthorhombic space group Pbca, with a = 17.3149(5) A, b = 14.6862(4) A, c = 21.0507(6) A, and Z = 8. Magnetization vs temperature data obtained in 100 G suggest that the compound exhibits dominant one-dimensional ferromagnetic coupling and that it subsequently undergoes an antiferromagnetic phase transition below TN approximately 4 K. Results of magnetization vs applied field experiments show that the compound is a metamagnet with a critical field of approximately 3 kG at 1.8 K. In the nominally antiferromagnetic state, apparent canting of the moments gives rise to a small amount of hysteresis. This picture is supported by ac susceptibility data. The 57Fe Mössbauer spectrum exhibits the expected decamethylferrocenium unresolved quadrupole doublet (delta = 0.53 mm/s) at 77 K and magnetic hyperfine splitting, Hint = 37.9 T, corresponding to long-range magnetic order at 1.63 K.

  18. Loss of MeCP2 Causes Urological Dysfunction and Contributes to Death by Kidney Failure in Mouse Models of Rett Syndrome.

    Science.gov (United States)

    Ward, Christopher S; Huang, Teng-Wei; Herrera, José A; Samaco, Rodney C; Pitcher, Meagan R; Herron, Alan; Skinner, Steven A; Kaufmann, Walter E; Glaze, Daniel G; Percy, Alan K; Neul, Jeffrey L

    2016-01-01

    Rett Syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills during development, autonomic dysfunction, and an increased risk for premature lethality. Clinical experience identified a subset of individuals with RTT that present with urological dysfunction including individuals with frequent urinary tract infections, kidney stones, and urine retention requiring frequent catheterization for bladder voiding. To determine if urologic dysfunction is a feature of RTT, we queried the Rett Syndrome Natural History Study, a repository of clinical data from over 1000 individuals with RTT and found multiple instances of urological dysfunction. We then evaluated urological function in a mouse model of RTT and found an abnormal pattern of micturition. Both male and female mice possessing Mecp2 mutations show a decrease in urine output per micturition event. Furthermore, we identified signs of kidney failure secondary to urethral obstruction. Although genetic strain background significantly affects both survival and penetrance of the urethral obstruction phenotype, survival and penetrance of urethral obstruction do not directly correlate. We have identified an additional phenotype caused by loss of MeCP2, urological dysfunction. Furthermore, we urge caution in the interpretation of survival data as an endpoint in preclinical studies, especially where causes of mortality are poorly characterized.

  19. Characterization of Turbulent Processes by the Raman Lidar System Basil in the Frame of the HD(CP)2 Observational Prototype Experiment - Hope

    Science.gov (United States)

    Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Cacciani, Marco; Scoccione, Andrea; Behrendt, Andreas; Wulfmeyer, Volker

    2016-06-01

    Measurements carried out by the Raman lidar system BASIL are reported to demonstrate the capability of this instrument to characterize turbulent processes within the Convective Boundary Layer (CBL). In order to resolve the vertical profiles of turbulent variables, high resolution water vapour and temperature measurements, with a temporal resolution of 10 sec and a vertical resolution of 90 and 210 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of spectral and auto-covariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (IOP 5, 20 April 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. The noise errors are demonstrated to be small enough to allow the derivation of up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations with sufficient accuracy.

  20. Ethylene homo- and copolymerization chain-transfers: A perspective from supported (nBuCp)2ZrCl2 catalyst active centre distribution

    Indian Academy of Sciences (India)

    Muhammad Atiqullah; Mamdouh A Al-Harthi; Siripon Anantawaraskul; Abdul-hamid M Emwas

    2015-04-01

    Polymerization chain termination reactions and unsaturation of the polymer backbone end are related. Therefore, in this study, the parameters resulting from the modelling of the active centre distribution of the supported catalyst—silica/MAO/(nBuCp)2ZrCl2—were applied to evaluate the active-centredependent ethylene homo- and copolymerization rates, as well as the corresponding chain termination rates. This approach, from a microkinetic mechanistic viewpoint, elucidates better the 1-hexene-induced positive comonomer effect and chain transfer phenomenon. The kinetic expressions, developed on the basis of the proposed polymerization mechanisms, illustrate how the active site type-dependent chain transfer phenomenon is influenced by the different apparent termination rate constants and momoner concentrations. The active centrespecific molecular weight Mni (for the above homo- and copolymer), as a function of chain transfer probability, pCTi, varied as follows: log(pCTi) = log(mwru)−log(Mni) where mwru is the molecular weight of the repeat unit. The physical significance of this finding has been explained. The homo- and copolymer backbones showed all the three chain end unsaturations (vinyl, vinylidene, and trans-vinylene). The postulated polymerization mechanisms reveal the underlying polymer chemistry. The results of the present study will contribute to develop in future supported metallocene catalysts that will be useful to synthesize polyethylene precursors having varying chain end unsaturations, which can be eventually used to prepare functional polyethylenes.

  1. Case studies of the propagation characteristics of auroral TIDS with EISCAT CP2 data using maximum entropy cross-spectral analysis

    Directory of Open Access Journals (Sweden)

    S. Y. Ma

    Full Text Available In this paper case studies of propagation characteristics of two TIDs are presented which are induced by atmospheric gravity waves in the auroral F-region on a magnetic quiet day. By means of maximum entropy cross-spectral analysis of EISCAT CP2 data, apparent full wave-number vectors of the TIDs are obtained as a function of height. The analysis results show that the two events considered can be classified as moderately large-scale TID and medium-scale TID, respectively. One exhibits a dominant period of about 72 min, a mean horizontal phase speed of about 180 m/s (corresponding to a horizontal wavelength of about 780 km directed south-eastwards and a vertical phase speed of 55 m/s for a height of about 300 km. The other example shows a dominant period of 44 min, a mean horizontal phase velocity of about 160 m/s (corresponding to a horizontal wavelength of about 420 km directed southwestwards, and a vertical phase velocity of about 50 m/s at 250 km altitude.

    Key words. Ionosphere · Auroral ionosphere · Ionosphere-atmosphere interactions · Wave propagation

  2. The male-determining gene SRY is a hybrid of DGCR8 and SOX3, and is regulated by the transcription factor CP2.

    Science.gov (United States)

    Sato, Youichi; Shinka, Toshikatsu; Sakamoto, Kozue; Ewis, Ashraf A; Nakahori, Yutaka

    2010-04-01

    In mammals, sex is determined by the presence or absence of the Y chromosome that bears a male-dominant sex-determining gene SRY, which switches the differentiation of gonads into male testes. The molecular signaling mechanism turning on the switch, however, has remained unclear for 18 years since the identification of the gene. Here, we describe how this gene emerged and started to work. From amino acid homology, we realized that SRY is a hybrid gene between a portion of the first exon of DiGeorge syndrome critical region gene 8 (DGCR8) and the high-mobility group (HMG) box of SRY box-3 (SOX3) gene. We identified the regulatory sequence in the SRY promotor region by searching for a common motif shared with DGCR8 mRNA. From the motif search between DGCR8 mRNA and the SRY upstream sequence, we found that the transcription factor CP2 (TFCP2) binding motif is present in both. TFCP2 overexpression did not show a significant increase of SRY mRNA expression, and TFCP2 suppression by RNA interference (RNAi) significantly reduced SRY mRNA expression. Furthermore, electrophoretic mobility shift assay (EMSA) demonstrated that TFCP2 acts as a regulator by directly binding to the SRY promoter. We conclude that SRY is a hybrid gene composed of two genes, DGCR8 and SOX3; and TFCP2 is an essential transcription factor for SRY expression regulation.

  3. Association of polymorphism in the transcription factor LBP-1c/CP2/LSF gene with Alzheimer's disease and major depression.

    Science.gov (United States)

    Schahab, Schamim; Heun, Reinhard; Schmitz, Sandra; Maier, Wolfgang; Kölsch, Heike

    2006-01-01

    The transcription factor LBP-1c/CP2/LSF (LBP-1c) is a candidate gene for Alzheimer's disease (AD) because it is located in a putative hotspot for an AD risk gene on chromosome 12. We investigated the effect of LBP-1c polymorphism on the risk of AD in 162 AD patients, 180 patients with major depression as hospitalized controls and 225 healthy subjects. We observed no significant association of the LBP-1c A allele with AD. Nor did we detect an interaction of the LBP-1c A allele with the apolipoprotein E4 (ApoE4) allele or the low-density lipoprotein receptor-related protein T allele which could have been related to the risk of AD. However, exploratory data analysis revealed that the LBP-1c A allele might act as a protective factor in major depression. A recent study also described an association of another gene located on chromosome 12, the mannose 6-phosphatase receptor gene, with major depression. These data suggest the presence of a putative risk gene for major depression at chromosome 12.

  4. Haploinsufficiency of MeCP2-interacting transcriptional co-repressor SIN3A causes mild intellectual disability by affecting the development of cortical integrity.

    Science.gov (United States)

    Witteveen, Josefine S; Willemsen, Marjolein H; Dombroski, Thaís C D; van Bakel, Nick H M; Nillesen, Willy M; van Hulten, Josephus A; Jansen, Eric J R; Verkaik, Dave; Veenstra-Knol, Hermine E; van Ravenswaaij-Arts, Conny M A; Wassink-Ruiter, Jolien S Klein; Vincent, Marie; David, Albert; Le Caignec, Cedric; Schieving, Jolanda; Gilissen, Christian; Foulds, Nicola; Rump, Patrick; Strom, Tim; Cremer, Kirsten; Zink, Alexander M; Engels, Hartmut; de Munnik, Sonja A; Visser, Jasper E; Brunner, Han G; Martens, Gerard J M; Pfundt, Rolph; Kleefstra, Tjitske; Kolk, Sharon M

    2016-08-01

    Numerous genes are associated with neurodevelopmental disorders such as intellectual disability and autism spectrum disorder (ASD), but their dysfunction is often poorly characterized. Here we identified dominant mutations in the gene encoding the transcriptional repressor and MeCP2 interactor switch-insensitive 3 family member A (SIN3A; chromosome 15q24.2) in individuals who, in addition to mild intellectual disability and ASD, share striking features, including facial dysmorphisms, microcephaly and short stature. This phenotype is highly related to that of individuals with atypical 15q24 microdeletions, linking SIN3A to this microdeletion syndrome. Brain magnetic resonance imaging showed subtle abnormalities, including corpus callosum hypoplasia and ventriculomegaly. Intriguingly, in vivo functional knockdown of Sin3a led to reduced cortical neurogenesis, altered neuronal identity and aberrant corticocortical projections in the developing mouse brain. Together, our data establish that haploinsufficiency of SIN3A is associated with mild syndromic intellectual disability and that SIN3A can be considered to be a key transcriptional regulator of cortical brain development.

  5. Loss of MeCP2 Causes Urological Dysfunction and Contributes to Death by Kidney Failure in Mouse Models of Rett Syndrome

    Science.gov (United States)

    Ward, Christopher S.; Huang, Teng-Wei; Herrera, José A.; Samaco, Rodney C.; Pitcher, Meagan R.; Herron, Alan; Skinner, Steven A.; Kaufmann, Walter E.; Glaze, Daniel G.; Percy, Alan K.; Neul, Jeffrey L.

    2016-01-01

    Rett Syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills during development, autonomic dysfunction, and an increased risk for premature lethality. Clinical experience identified a subset of individuals with RTT that present with urological dysfunction including individuals with frequent urinary tract infections, kidney stones, and urine retention requiring frequent catheterization for bladder voiding. To determine if urologic dysfunction is a feature of RTT, we queried the Rett Syndrome Natural History Study, a repository of clinical data from over 1000 individuals with RTT and found multiple instances of urological dysfunction. We then evaluated urological function in a mouse model of RTT and found an abnormal pattern of micturition. Both male and female mice possessing Mecp2 mutations show a decrease in urine output per micturition event. Furthermore, we identified signs of kidney failure secondary to urethral obstruction. Although genetic strain background significantly affects both survival and penetrance of the urethral obstruction phenotype, survival and penetrance of urethral obstruction do not directly correlate. We have identified an additional phenotype caused by loss of MeCP2, urological dysfunction. Furthermore, we urge caution in the interpretation of survival data as an endpoint in preclinical studies, especially where causes of mortality are poorly characterized. PMID:27828991

  6. Improvement of the Rett syndrome phenotype in a MeCP2 mouse model upon treatment with levodopa and a dopa-decarboxylase inhibitor.

    Science.gov (United States)

    Szczesna, Karolina; de la Caridad, Olga; Petazzi, Paolo; Soler, Marta; Roa, Laura; Saez, Mauricio A; Fourcade, Stéphane; Pujol, Aurora; Artuch-Iriberri, Rafael; Molero-Luis, Marta; Vidal, August; Huertas, Dori; Esteller, Manel

    2014-11-01

    Rett Syndrome is a neurodevelopmental autism spectrum disorder caused by mutations in the gene coding for methyl CpG-binding protein (MeCP2). The disease is characterized by abnormal motor, respiratory, cognitive impairment, and autistic-like behaviors. No effective treatment of the disorder is available. Mecp2 knockout mice have a range of physiological and neurological abnormalities that resemble the human syndrome and can be used as a model to interrogate new therapies. Herein, we show that the combined administration of Levodopa and a Dopa-decarboxylase inhibitor in RTT mouse models is well tolerated, diminishes RTT-associated symptoms, and increases life span. The amelioration of RTT symptomatology is particularly significant in those features controlled by the dopaminergic pathway in the nigrostratium, such as mobility, tremor, and breathing. Most important, the improvement of the RTT phenotype upon use of the combined treatment is reflected at the cellular level by the development of neuronal dendritic growth. However, much work is required to extend the duration of the benefit of the described preclinical treatment.

  7. Temporal Spectral Analysis of Be stars observed with CoRoT satellite

    Science.gov (United States)

    Emilio, Marcelo; Janot Pacheco, Eduardo; Andrade, Laerte

    . Nevertheless, to measure frequencies with great accuracy in stars requires both high photometric precision and high time-frequency resolution. The CoRoT (Convection, Rotation and planetary Transits) satellite opens for the first time in history the possibility of fulfilling this goal. CoRoT is an experiment of astronomy dedicated to seismology and the detection of extrasolar planet transits. It was launched on December 2006 in an inertial polar orbit at an altitude of 897 mathrm{km}. The instrument is fed by a phi=27 textrm{cm} telescope. Its scientific program is three-fold consisting of: (1) The seismology core program (SISMO), which concerns the seismic study of ˜10 bright (6CoRoT ID 102761769 observed by CoRoT satellite. We found two close frequencies related to the .CoRoT ID 102761769 star. They are 2.465 c d(-1) (28.5 mathrm{mu Hz}) and 2.441 c d(-1) (28.2 mathrm{mu Hz}). The precision to which those frequencies were found is 0.018 c d(-1) (0.2 mathrm{mu Hz}). The projected stellar rotation was estimated to be 120 km s(-1) from the Fourier transform of spectral lines. If CoRoT-ID 102761769 is a typical Galactic Be star it rotates near the critical velocity. The critical rotation frequency of a typical B5-6 star is about 3.5 c d(-1) (40.5 mathrm{mu Hz}), which implies that the above frequencies are really caused by stellar pulsations rather than star's rotation. HD 171219 frequencies 1.113, 1.130, 1.146 c * d(-1) form a triplet with the

  8. Transiting exoplanets from the CoRoT space mission XXVIII. CoRoT-33b, an object in the brown dwarf desert with 2:3 commensurability with its host star

    CERN Document Server

    Csizmadia, Sz; Gandolfi, G; Deleuil, M; Bouchy, M; Fridlund, M; Szabados, L; Parviainen, H; Cabrera, J; Aigrain, S; Alonso, R; Almenara, J M; Baglin, A; Bordé, P; Bonomo, A S; Deeg, H J; Dıaz, R F; Erikson, A; Ferraz-Mello, S; Santos, M Tadeu dos; Guenther, E W; Guillot, T; Grziwa, S; Hébrard, G; Klagyivik, P; Ollivier, M; Pätzold, M; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Mazeh, T; Wuchterl, G; Carpano, S; Ofir, A

    2015-01-01

    We report the detection of a rare transiting brown dwarf with a mass of 59 M_Jup and radius of 1.1 R_Jup around the metal-rich, [Fe/H] = +0.44, G9V star CoRoT-33. The orbit is eccentric (e = 0.07) with a period of 5.82 d. The companion, CoRoT-33b, is thus a new member in the so-called brown dwarf desert. The orbital period is within 3% to a 3:2 resonance with the rotational period of the star. CoRoT-33b may be an important test case for tidal evolution studies. The true frequency of brown dwarfs close to their host stars (P < 10 d) is estimated to be approximately 0.2% which is about six times smaller than the frequency of hot Jupiters in the same period range. We suspect that the frequency of brown dwarfs declines faster with decreasing period than that of giant planets.

  9. Clinical feature of Rett syndrome and MeCP2 genotype/phenotype correlation analysis%Rett综合征的临床特征及MeCP2的基因型与表型的关系研究

    Institute of Scientific and Technical Information of China (English)

    包新华; 潘虹; 宋福英; 吴希如

    2004-01-01

    目的总结Rett综合征(RTT)的临床特点,探讨甲基化CpG结合蛋白2(MeCP2)基因突变型与表型的关系.方法北京大学第一医院儿科1987年以来诊断的RTT66例,每1~2年对本组患儿进行1次临床随访,并观察左旋肉碱的治疗反应.应用PCB、测序方法对39例患儿进行突变基因分析.结果患儿3~38个月起病,59例(89%)患儿于7个月~6岁丧失手的功能,66例(100%)患儿1~5岁出现手的刻板动作,56例(85%)患儿11个月~8岁语言完全丧失,21%的患儿于2岁9个月~15岁丧失原已获得的行走能力.头围小、惊厥、呼吸节律异常、咬牙、脊柱侧凸或后凸均很常见.左旋肉碱治疗17例,8周后6例症状改善.39例进行MeCP2基因分析者中有25例(64%)发现突变,其中2例无义突变C502T(氨基酸改变R168X)患儿均死亡,2例C397T(氨基酸改变R133C)和1例A398T(氨基酸改变R133H)突变者均保留语言.结论RTT特征性的表现为头围增长缓慢,手的失用与刻板动作,语言倒退,左旋肉碱可以改善部分患儿的临床症状.MeCP2基因型与表型之间有一定的相关性.

  10. Tidal evolution of CoRoT massive planets and brown dwarfs and of their host stars

    CERN Document Server

    Ferraz-Mello, Sylvio

    2016-01-01

    Aims: Revisit and improvement of the main results obtained in the study of the tidal evolution of several massive CoRoT planets and brown dwarfs and of the rotation of their host stars. Methods: Simulations of the past and future evolution of the orbital and rotational elements of the systems under the joint action of the tidal torques and the braking due to the stellar wind. Results: Presentation of several paradigms and significant examples of tidal evolution in extrasolar planetary systems. It is shown that the high quality of the photometric and spectrographic observations of the CoRoT objects allow for a precise study of their past and future evolution and to estimate the tidal parameters ruling the dissipation in the systems.

  11. Galactic archaeology with asteroseismology and spectroscopy: Red giants observed by CoRoT and APOGEE

    Science.gov (United States)

    Anders, F.; Chiappini, C.; Rodrigues, T. S.; Miglio, A.; Montalbán, J.; Mosser, B.; Girardi, L.; Valentini, M.; Noels, A.; Morel, T.; Johnson, J. A.; Schultheis, M.; Baudin, F.; de Assis Peralta, R.; Hekker, S.; Themeßl, N.; Kallinger, T.; García, R. A.; Mathur, S.; Baglin, A.; Santiago, B. X.; Martig, M.; Minchev, I.; Steinmetz, M.; da Costa, L. N.; Maia, M. A. G.; Allende Prieto, C.; Cunha, K.; Beers, T. C.; Epstein, C.; García Pérez, A. E.; García-Hernández, D. A.; Harding, P.; Holtzman, J.; Majewski, S. R.; Mészáros, Sz.; Nidever, D.; Pan, K.; Pinsonneault, M.; Schiavon, R. P.; Schneider, D. P.; Shetrone, M. D.; Stassun, K.; Zamora, O.; Zasowski, G.

    2017-01-01

    With the advent of the space missions CoRoT and Kepler, it has recently become feasible to determine precise asteroseismic masses and relative ages for large samples of red giant stars. We present the CoRoGEE dataset, obtained from CoRoT light curves for 606 red giants in two fields of the Galactic disc that have been co-observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We used the Bayesian parameter estimation code PARAM to calculate distances, extinctions, masses, and ages for these stars in a homogeneous analysis, resulting in relative statistical uncertainties of ≲2% in distance, 4% in radius, 9% in mass and 25% in age. We also assessed systematic age uncertainties stemming from different input physics and mass loss. We discuss the correlation between ages and chemical abundance patterns of field stars over a broad radial range of the Milky Way disc (5 kpc

  12. Disentangling planetary and stellar activity features in the CoRoT-2 light curve

    Science.gov (United States)

    Bruno, G.; Deleuil, M.; Almenara, J.-M.; Barros, S. C. C.; Lanza, A. F.; Montalto, M.; Boisse, I.; Santerne, A.; Lagrange, A.-M.; Meunier, N.

    2016-11-01

    Aims: Stellar activity is an important source of systematic errors and uncertainties in the characterization of exoplanets. Most of the techniques used to correct for this activity focus on an ad hoc data reduction. Methods: We have developed a software for the combined fit of transits and stellar activity features in high-precision long-duration photometry. Our aim is to take advantage of the modelling to derive correct stellar and planetary parameters, even in the case of strong stellar activity. Results: We use an analytic approach to model the light curve. The code KSint, modified by adding the evolution of active regions, is implemented into our Bayesian modelling package PASTIS. The code is then applied to the light curve of CoRoT-2. The light curve is divided in segments to reduce the number of free parameters needed by the fit. We perform a Markov chain Monte Carlo analysis in two ways. In the first, we perform a global and independent modelling of each segment of the light curve, transits are not normalized and are fitted together with the activity features, and occulted features are taken into account during the transit fit. In the second, we normalize the transits with a model of the non-occulted activity features, and then we apply a standard transit fit, which does not take the occulted features into account. Conclusions: Our model recovers the activity features coverage of the stellar surface and different rotation periods for different features. We find variations in the transit parameters of different segments and show that they are likely due to the division applied to the light curve. Neglecting stellar activity or even only bright spots while normalizing the transits yields a 1.2σ larger and 2.3σ smaller transit depth, respectively. The stellar density also presents up to 2.5σ differences depending on the normalization technique. Our analysis confirms the inflated radius of the planet (1.475 ± 0.031RJ) found by other authors. We show that

  13. Corotational Instability of Inertial-Acoustic Modes in Black Hole Accretion Discs and Quasi-Periodic Oscillations

    CERN Document Server

    Lai, Dong

    2008-01-01

    We study the global stability of non-axisymmetric p-modes (also called inertial-acoustic modes) trapped in the inner-most regions of accretion discs around black holes. We show that the lowest-order (highest-frequency) p-modes, with frequencies $\\omega=(0.5-0.7) m\\Omega_{\\rm ISCO}$, can be overstable due to general relativistic effects, according to which the radial epicyclic frequency is a non-monotonic function of radius near the black hole. The mode is trapped inside the corotation resonance radius and carries a negative energy. The mode growth arises primarily from wave absorption at the corotation resonance, and the sign of the wave absorption depends on the gradient of the disc vortensity. When the mode frequency is sufficiently high, such that the slope of the vortensity is positive at corotation positive wave energy is absorbed at the resonance, leading to the growth of mode amplitude. We also study how the rapid radial inflow at the inner edge of the disc affects the mode trapping and growth. Our ana...

  14. Constraining physics of very hot super-Earths with the James Webb Telescope. The case of Corot-7b

    CERN Document Server

    Samuel, Benjamin; Rouan, Daniel; Forget, François; Léger, Alain; Schneider, Jean

    2014-01-01

    Super-Earths with solid surfaces such CoRot-7b and Kepler-10b are expected to be extremely hot. It has been suggested that they must be atmosphere-free and that a lava ocean is present on their hot dayside. Here, we use several dedicated thermal models to study how observations with NIRSPEC on the JWST could further confirm and constrain, or reject the atmosphere-free lava ocean planet model for very hot super-Earths. Using CoRoT-7b as a working case, we explore the consequences on the phase-curve of a non tidal-locked rotation, with/without an atmosphere, and for different values of the albedo. We simulate future observations of the reflected light and thermal emission from CoRoT-7b with NIRSPEC-JWST and look for detectable signatures, such as time lag, as well as the possibility to retrieve the latitudinal surface temperature distribution. We demonstrate that we should be able to constrain several parameters after observations of two orbits (42 h) with a broad range of wavelengths: i)The Bond albedo is retr...

  15. CoRoT 105906206: a short-period and totally eclipsing binary with a Delta Scuti type pulsator

    CERN Document Server

    da Silva, Ronaldo; Gandolfi, Davide; Lehmann, Holger; Hatzes, Artie P

    2014-01-01

    Eclipsing binary systems with pulsating components allow the determination of several physical parameters of the stars, such as mass and radius, that, when combined with the pulsation properties, can be used to constrain the modeling of stellar interiors and evolution. Hereby, we present the results of the study of CoRoT 105906206, an eclipsing binary system with a pulsating component located in the CoRoT LRc02 field. The analysis of the CoRoT light curve was complemented by high-resolution spectra from the Sandiford at McDonald Observatory and FEROS at ESO spectrographs, which revealed a double-lined spectroscopic binary. We used an iterative procedure to separate the pulsation-induced photometric variations from the eclipse signals. First, a Fourier analysis was used to identify the significant frequencies and amplitudes due to pulsations. Second, after removing the contribution of the pulsations from the light curve we applied the PIKAIA genetic-algorithm approach to derive the best parameters that describ...

  16. From CoRoT 102899501 to the Sun. A time evolution model of chromospheric activity on the main sequence

    CERN Document Server

    Gondoin, P; Fridlund, M; Frasca, A; Guenther, E W; Hatzes, A; Deeg, H J; Parviainen, H; Eigmueller, P; Deleuil, M

    2012-01-01

    Using a model based on the rotational modulation of the visibility of active regions, we analyse the high-accuracy CoRoT lightcurve of the active young star CoRoT102899501. Spectroscopic follow-up observations are used to derive its fundamental parameters. We compare its chromospheric activity level with a model of chrosmospheric activity evolution established by combining relationships between the R'HK index and the Rossby number with a recent model of stellar rotation evolution on the main sequence. We measure the spot coverage of the stellar surface as a function of time, and find evidence for a tentative increase from 5-14% at the beginning of the observing run to 13-29% 35 days later. A high level of magnetic activity on CoRoT102899501 is corroborated by a strong emission in the Balmer and Ca II HK lines (logR'HK ~ -4). The starspots used as tracers of the star rotation constrain the rotation period to 1.625+/-0.002 days and do not show evidence for differential rotation. The effective temperature (Teff=...

  17. MIARMA: An information preserving method for filling gaps in time series. Application to CoRoT light curves

    CERN Document Server

    Pascual-Granado, J; Suárez, J C

    2014-01-01

    The method here presented intends to minimize the effect of the gaps in the power spectra by gap-filling preserving the original information, that is, in the case of asteroseismology, the stellar oscillation frequency content. We make use of a forward-backward predictor based on autoregressive moving average modelling (ARMA) in the time domain. The method MIARMA is particularly suitable for replacing invalid data such as those present in the light curves of the CoRoT satellite due to the pass through the South Atlantic Anomaly, and eventually for the data gathered by the NASA planet hunter Kepler. We select a sample of stars from the ultra-precise photometry collected by the asteroseismic camera on board the CoRoT satellite: the {\\delta} Scuti star HD 174966, showing periodic variations of the same order as the CoRoT observational window, the Be star HD 51193, showing longer time variations, and the solar-like HD 49933, with rapid time variations. We showed that in some cases linear interpolations are less re...

  18. CoRoT-22 b: a validated 4.9 RE exoplanet in 10-day orbit

    CERN Document Server

    Moutou, C; Diaz, R F; Alonso, R; Deleuil, M; Guenther, E; Pasternacki, T; Aigrain, S; Baglin, A; Barge, P; Bonomo, A; Borde, P; Bouchy, F; Cabrera, J; Carpano, S; Cochran, W; Csizmadia, Sz; Deeg, H; Dvorak, R; Endl, M; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Guillot, T; Artzes, A; Hebrard, G; Lovis, C; Lammer, H; McQueen, P; Mazeh, T; Ofir, A; Ollivier, M; Paetzold, M; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Tingley, B; Wuchterl, G

    2014-01-01

    The CoRoT satellite has provided high-precision photometric light curves for more than 163,000 stars and found several hundreds of transiting systems compatible with a planetary scenario. If ground-based velocimetric observations are the best way to identify the actual planets among many possible configurations of eclipsing binary systems, recent transit surveys have shown that it is not always within reach of the radial-velocity detection limits. In this paper, we present a transiting exoplanet candidate discovered by CoRoT whose nature cannot be established from ground-based observations, and where extensive analyses are used to validate the planet scenario. They are based on observing constraints from radial-velocity spectroscopy, adaptive optics imaging and the CoRoT transit shape, as well as from priors on stellar populations, planet and multiple stellar systems frequency. We use the fully Bayesian approach developed in the PASTIS analysis software, and conclude that the planet scenario is at least 1400 ...

  19. Effect of Annealling Treatment on Microstrcture and Properties of Automobile CP2 Rolled Pure Titanium Plate%退火处理对工业汽车轧制CP2钛板材组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    王颜

    2015-01-01

    对商业轧制CP2钛板进行50%冷轧后再于650℃进行不同时间退火,随后室温下进行单轴拉伸实验,研究了退火处理对钛板组织和性能的影响.结果表明,冷轧后650℃下退火,组织得到细化,性能得到改善.与原始板材相比,冷轧未退火材料强度提高而塑性急剧下降;而对于冷轧后退火材料,强度稍微降低而塑性得到明显改善.随退火时间的延长,晶粒长大明显.

  20. Anaplerotic triheptanoin diet enhances mitochondrial substrate use to remodel the metabolome and improve lifespan, motor function, and sociability in MeCP2-null mice.

    Directory of Open Access Journals (Sweden)

    Min Jung Park

    Full Text Available Rett syndrome (RTT is an autism spectrum disorder (ASD caused by mutations in the X-linked MECP2 gene that encodes methyl-CpG binding protein 2 (MeCP2. Symptoms range in severity and include psychomotor disabilities, seizures, ataxia, and intellectual disability. Symptom onset is between 6-18 months of age, a critical period of brain development that is highly energy-dependent. Notably, patients with RTT have evidence of mitochondrial dysfunction, as well as abnormal levels of the adipokines leptin and adiponectin, suggesting overall metabolic imbalance. We hypothesized that one contributor to RTT symptoms is energy deficiency due to defective nutrient substrate utilization by the TCA cycle. This energy deficit would lead to a metabolic imbalance, but would be treatable by providing anaplerotic substrates to the TCA cycle to enhance energy production. We show that dietary therapy with triheptanoin significantly increased longevity and improved motor function and social interaction in male mice hemizygous for Mecp2 knockout. Anaplerotic therapy in Mecp2 knockout mice also improved indicators of impaired substrate utilization, decreased adiposity, increased glucose tolerance and insulin sensitivity, decreased serum leptin and insulin, and improved mitochondrial morphology in skeletal muscle. Untargeted metabolomics of liver and skeletal muscle revealed increases in levels of TCA cycle intermediates with triheptanoin diet, as well as normalizations of glucose and fatty acid biochemical pathways consistent with the improved metabolic phenotype in Mecp2 knockout mice on triheptanoin. These results suggest that an approach using dietary supplementation with anaplerotic substrate is effective in improving symptoms and metabolic health in RTT.

  1. A circumbinary disc model for the variability of the eclipsing binary CoRoT 223992193

    CERN Document Server

    Terquem, Caroline; Bouvier, Jérôme

    2015-01-01

    We calculate the flux received from a binary system obscured by a circumbinary disc. The disc is modelled using two dimensional hydrodynamical simulations, and the vertical structure is derived by assuming it is isothermal. The gravitational torque from the binary creates a cavity in the disc's inner parts. If the line of sight along which the system is observed has a high inclination $I$, it intersects the disc and some absorption is produced. As the system is not axisymmetric, the resulting light curve displays variability. We calculate the absorption and produce light curves for different values of the dust disc aspect ratio $H/r$ and mass of dust in the cavity $M_{\\rm dust}$. This model is applied to the high inclination ($I=85^{\\circ}$) eclipsing binary CoRoT 223992193, which shows 5-10% residual photometric variability after the eclipses and a spot model are subtracted. We find that such variations for $I \\sim 85^{\\circ}$ can be obtained for $H/r=10^{-3}$ and $M_{\\rm dust} \\ge 10^{-12}$ M$_{\\odot}$. For...

  2. Observation of Energetic particles between a pair of Corotating Interaction Regions

    CERN Document Server

    Wu, Z; Li, G; Zhao, L L; Ebert, R W; Desai, M I; Mason, G M; Lavraud, B; Zhao, L; Liu, Y C -M; Guo, F; Tang, C L; Landi, E; Sauvaud, J

    2014-01-01

    We report observations of the acceleration and trapping of energetic ions and electrons between a pair of corotating interaction regions (CIRs). The event occurred in Carrington Rotation 2060. Observed at spacecraft STEREO-B, the two CIRs were separated by less than 5 days. In contrast to other CIR events, the fluxes of energetic ions and electrons in this event reached their maxima between the trailing-edge of the first CIR and the leading edge of the second CIR. The radial magnetic field (Br) reversed its sense and the anisotropy of the flux also changed from sunward to anti-sunward between the two CIRs. Furthermore, there was an extended period of counter-streaming suprathermal electrons between the two CIRs. Similar observations for this event were also obtained for ACE and STEREO-A. We conjecture that these observations were due to a "U-shape" large scale magnetic field topology connecting the reverse shock of the first CIR and the forward shock of the second CIR. Such a disconnected U-shaped magnetic fi...

  3. Coupling between corotation and Lindblad resonances in the elliptic planar three-body problem

    CERN Document Server

    Moutamid, Maryame El; Renner, Stéfan

    2013-01-01

    We investigate the dynamics of two satellites with masses $\\mu_s$ and $\\mu'_s$ orbiting a massive central planet in a common plane, near a first order mean motion resonance $m$+1:$m$ ($m$ integer). We consider only the resonant terms of first order in eccentricity in the disturbing potential of the satellites, plus the secular terms causing the orbital apsidal precessions. We obtain a two-degree of freedom system, associated with the two critical resonant angles $\\phi= (m+1)\\lambda' -m\\lambda - \\varpi$ and $\\phi'= (m+1)\\lambda' -m\\lambda - \\varpi'$, where $\\lambda$ and $\\varpi$ are the mean longitude and longitude of periapsis of $\\mu_s$, respectively, and where the primed quantities apply to $\\mu'_s$. We consider the special case where $\\mu_s \\rightarrow 0$ (restricted problem). The symmetry between the two angles $\\phi$ and $\\phi'$ is then broken, leading to two different kinds of resonances, classically referred to as Corotation Eccentric resonance (CER) and Lindblad Eccentric Resonance (LER), respectively...

  4. The physics of pressure variation in microchannels within corotating or static discs

    Science.gov (United States)

    Guha, Abhijit; Sengupta, Sayantan

    2016-10-01

    We formulate a comprehensive analysis for the radial pressure variation in flow through microchannels within corotating (or static) discs, which is important for its fundamental value and application potential in macrofluidic and microfluidic devices. The uniqueness and utility of the present approach emanate from our ability to describe the physics completely in terms of non-dimensional numbers and to determine quantitatively the separate roles of inertia, centrifugal force, Coriolis force, and viscous effects in the overall radial pressure difference (Δpio). It is established here that the aspect ratio (ratio of inter-disc spacing and disc radius) plays only a secondary role as an independent parameter, its major role being contained within a newly identified dynamic similarity number (Ds). For radial inflow, it is shown that the magnitude of Δpio decreases monotonically as the tangential speed ratio (γ) increases but exhibits a minima when Ds is varied. For radial outflow, it is shown that Δpio increases monotonically as the flow coefficient (ϕ) decreases but evinces a maxima when Ds is varied. It is further shown that for the radial inflow case, the minima in the magnitude of Δpio exist even when the rotational speed of the discs is reduced to zero (static discs). The demonstrated existence of these extrema (i.e., minima for radial inflow and maxima for radial outflow) creates the scope for device optimization.

  5. Planetary eclipse mapping of CoRoT-2a. Evolution, differential rotation, and spot migration

    CERN Document Server

    Huber, K F; Wolter, U; Schmitt, J H M M

    2010-01-01

    The lightcurve of CoRoT-2 shows substantial rotational modulation and deformations of the planet's transit profiles caused by starspots. We consistently model the entire lightcurve, including both rotational modulation and transits, stretching over approximately 30 stellar rotations and 79 transits. The spot distribution and its evolution on the noneclipsed and eclipsed surface sections are presented and analyzed, making use of the high resolution achievable under the transit path. We measure the average surface brightness on the eclipsed section to be (5\\pm1) % lower than on the noneclipsed section. Adopting a solar spot contrast, the spot coverage on the entire surface reaches up to 19 % and a maximum of almost 40 % on the eclipsed section. Features under the transit path, i.e. close to the equator, rotate with a period close to 4.55 days. Significantly higher rotation periods are found for features on the noneclipsed section indicating a differential rotation of $\\Delta \\Omega > 0.1$. Spotted and unspotted...

  6. Polymer solutions in co-rotating Taylor-Couette flow without vorticity

    Science.gov (United States)

    Zell, A.; Wagner, C.

    2012-02-01

    We present experimental results of the flow of dilute and semi-dilute polymer solutions in co-rotating Taylor-Couette cylinders. The experimental set-up consists of a modified Mars II rheometer (Thermo Scientific) with two drive units that are mounted opposite each other. The rotational velocities of the inner and outer cylinders are chosen in a way such that the angular velocity has a 1/r profile and the flow is free of vorticity, but the direction of elongation is not constant, but rotates with the flow. Our particle image velocimetry (PIV) measurements show that for polymer solutions without shear thinning the flow is indeed free of vorticity and is equal to a stagnation point flow at a given position and a given instant in time. In contrast, torque measurements reveal that the stresses are identical to the stresses that are present in a plane shear flow. Thus, we find that for polymer solutions a flow with vorticity and a constant direction of elongation is equal to a flow without vorticity in which the direction of elongation is rotating. Finally, we show that for shear thinning solutions the flow velocity becomes non-monotonic through the gap and resembles a pluglike profile which is known from the Poiseuille flow.

  7. Halting Migration: Numerical Calculations of Corotation Torques in the Weakly Nonlinear Regime

    CERN Document Server

    Duffell, Paul C

    2014-01-01

    Planets in their formative years can migrate due to the influence of gravitational torques in the protoplanetary disk they inhabit. For low-mass planets in an isothermal disk, it is known that there is a strong negative torque on the planet due to its linear perturbation to the disk, causing fast inward migration. The current investigation demonstrates that in these same isothermal disks, for intermediate-mass planets, there is a strong positive nonlinear corotation torque due to the effects of gas being pulled through a gap on horseshoe orbits. For intermediate-mass planets, this positive torque can partially or completely cancel the linear (Type I) torque, leading to slower or outward migration, even in an isothermal disk. The effect is most significant for Super-Earth and Sub-Jovian planets, during the transition from a low-mass linear perturber to a non-linear gap-opening planet, when the planet has opened a so-called 'partial gap'. In this study, numerical calculations of planet-disk interactions calcula...

  8. Large-deflection statics analysis of active cardiac catheters through co-rotational modelling.

    Science.gov (United States)

    Peng Qi; Chen Qiu; Mehndiratta, Aadarsh; I-Ming Chen; Haoyong Yu

    2016-08-01

    This paper presents a co-rotational concept for large-deflection formulation of cardiac catheters. Using this approach, the catheter is first discretized with a number of equal length beam elements and nodes, and the rigid body motions of an individual beam element are separated from its deformations. Therefore, it is adequate for modelling arbitrarily large deflections of a catheter with linear elastic analysis at the local element level. A novel design of active cardiac catheter of 9 Fr in diameter at the beginning of the paper is proposed, which is based on the contra-rotating double helix patterns and is improved from the previous prototypes. The modelling section is followed by MATLAB simulations of various deflections when the catheter is exerted different types of loads. This proves the feasibility of the presented modelling approach. To the best knowledge of the authors, it is the first to utilize this methodology for large-deflection static analysis of the catheter, which will enable more accurate control of robot-assisted cardiac catheterization procedures. Future work would include further experimental validations.

  9. Derivation of Capture Probabilities for the Corotation Eccentric Mean Motion Resonances

    CERN Document Server

    Moutamid, Maryame El; Renner, Stéfan

    2016-01-01

    We study in this paper the capture of a massless particle into an isolated, first order Corotation Eccentric Resonance (CER), in the framework of the Planar, Eccentric and Restricted Three-Body problem near a m+1:m mean motion commensurability (m integer). While capture into Lindblad Eccentric Resonances (where the perturber's orbit is circular) has been investigated years ago, capture into CER (where the perturber's orbit is elliptic) has not yet been investigated in detail. Here, we derive the generic equations of motion near a CER in the general case where both the perturber and the test particle migrate. We derive the probability of capture in that context, and we examine more closely two particular cases: (i) if only the perturber is migrating, capture is possible only if the migration is outward from the primary. Notably, the probability of capture is independent of the way the perturber migrates outward; (ii) if only the test particle is migrating, then capture is possible only if the algebraic value o...

  10. Plaskett's Star: Analysis of the CoRoT photometric data

    CERN Document Server

    Mahy, L; Baudin, F; Rauw, G; Godart, M; Morel, T; Degroote, P; Aerts, C; Blomme, R; Cuypers, J; Noels, A; Michel, E; Baglin, A; Auvergne, M; Catala, C; Samadi, R

    2010-01-01

    The SRa02 of the CoRoT space mission for Asteroseismology was partly devoted to stars belonging to the Mon OB2 association. An intense monitoring was performed on Plaskett's Star (HD47129) and the unprecedented quality of the light curve allows us to shed new light on this very massive, non-eclipsing binary system. We particularly aimed at detecting periodic variability which might be associated with pulsations or interactions between both components. We also searched for variations related to the orbital cycle which could help to constrain the inclination and the morphology of the binary system. A Fourier-based prewhitening and a multiperiodic fitting procedure were applied to analyse the time series and extract the frequencies of variations. We describe the noise properties to tentatively define an appropriate significance criterion, to only point out the peaks at a certain significance level. We also detect the variations related to the orbital motion and study them by using the NIGHTFALL program. The peri...

  11. Existence of Corotating and Counter-Rotating Vortex Pairs for Active Scalar Equations

    Science.gov (United States)

    Hmidi, Taoufik; Mateu, Joan

    2017-03-01

    In this paper, we study the existence of corotating and counter-rotating pairs of simply connected patches for Euler equations and the {(SQG)_{α}} equations with {α in (0,1)}. From the numerical experiments implemented for Euler equations in Deem and Zabusky (Phys Rev Lett 40(13):859-862, 1978), Pierrehumbert (J Fluid Mech 99:129-144, 1980), Saffman and Szeto (Phys Fluids 23(12):2339-2342, 1980) it is conjectured the existence of a curve of steady vortex pairs passing through the point vortex pairs. There are some analytical proofs based on variational principle (Keady in J Aust Math Soc Ser B 26:487-502, 1985; Turkington in Nonlinear Anal Theory Methods Appl 9(4):351-369, 1985); however, they do not give enough information about the pairs, such as the uniqueness or the topological structure of each single vortex. We intend in this paper to give direct proofs confirming the numerical experiments and extend these results for the {(SQG)_{α}} equation when {α in (0,1)}. The proofs rely on the contour dynamics equations combined with a desingularization of the point vortex pairs and the application of the implicit function theorem.

  12. Adaptive, Small-Rotation-Based, Corotational Technique for Analysis of 2D Nonlinear Elastic Frames

    Directory of Open Access Journals (Sweden)

    Jaroon Rungamornrat

    2014-01-01

    Full Text Available This paper presents an efficient and accurate numerical technique for analysis of two-dimensional frames accounted for both geometric nonlinearity and nonlinear elastic material behavior. An adaptive remeshing scheme is utilized to optimally discretize a structure into a set of elements where the total displacement can be decomposed into the rigid body movement and one possessing small rotations. This, therefore, allows the force-deformation relationship for the latter part to be established based on small-rotation-based kinematics. Nonlinear elastic material model is integrated into such relation via the prescribed nonlinear moment-curvature relationship. The global force-displacement relation for each element can be derived subsequently using corotational formulations. A final system of nonlinear algebraic equations along with its associated gradient matrix for the whole structure is obtained by a standard assembly procedure and then solved numerically by Newton-Raphson algorithm. A selected set of results is then reported to demonstrate and discuss the computational performance including the accuracy and convergence of the proposed technique.

  13. Observations of energetic particles between a pair of corotating interaction regions

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z.; Chen, Y.; Tang, C. L. [Institute of Space Sciences and School of Space Science and Physics, Shandong University at Weihai, Weihai 264209 (China); Li, G.; Zhao, L. L. [Department of Space Science and CSPAR, University of Alabama in Huntsville, AL 35899 (United States); Ebert, R. W.; Desai, M. I. [Southwest Research Institute, San Antonio, TX 78228 (United States); Mason, G. M. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Lavraud, B.; Sauvaud, J. [Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS) and Centre National de la Recherche Scientifique, UMR 5277, Toulouse (France); Zhao, L.; Landi, E. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48105 (United States); Liu, Y. C.-M. [State Key Laboratory of Space Weather, National Space Science Center, CAS. Beijing 100190 (China); Guo, F., E-mail: gang.li@uah.edu [Theoretical Division, Los Alamos National Laboratory, NM 87545 (United States)

    2014-01-20

    We report observations of the acceleration and trapping of energetic ions and electrons between a pair of corotating interaction regions (CIRs). The event occurred in Carrington Rotation 2060. Observed by the STEREO-B spacecraft, the two CIRs were separated by less than 5 days. In contrast to other CIR events, the fluxes of the energetic ions and electrons in this event reached their maxima between the trailing edge of the first CIR and the leading edge of the second CIR. The radial magnetic field (B{sub r} ) reversed its sense and the anisotropy of the flux also changed from Sunward to anti-Sunward between the two CIRs. Furthermore, there was an extended period of counterstreaming suprathermal electrons between the two CIRs. Similar observations for this event were also obtained with the Advanced Composition Explorer and STEREO-A. We conjecture that these observations were due to a U-shaped, large-scale magnetic field topology connecting the reverse shock of the first CIR and the forward shock of the second CIR. Such a disconnected U-shaped magnetic field topology may have formed due to magnetic reconnection in the upper corona.

  14. Cosmic-Ray Transport in Heliospheric Magnetic Structures. II. Modeling Particle Transport through Corotating Interaction Regions

    Science.gov (United States)

    Kopp, Andreas; Wiengarten, Tobias; Fichtner, Horst; Effenberger, Frederic; Kühl, Patrick; Heber, Bernd; Raath, Jan-Louis; Potgieter, Marius S.

    2017-03-01

    The transport of cosmic rays (CRs) in the heliosphere is determined by the properties of the solar wind plasma. The heliospheric plasma environment has been probed by spacecraft for decades and provides a unique opportunity for testing transport theories. Of particular interest for the three-dimensional (3D) heliospheric CR transport are structures such as corotating interaction regions (CIRs), which, due to the enhancement of the magnetic field strength and magnetic fluctuations within and due to the associated shocks as well as stream interfaces, do influence the CR diffusion and drift. In a three-fold series of papers, we investigate these effects by modeling inner-heliospheric solar wind conditions with the numerical magnetohydrodynamic (MHD) framework Cronos (Wiengarten et al., referred as Paper I), and the results serve as input to a transport code employing a stochastic differential equation approach (this paper). While, in Paper I, we presented results from 3D simulations with Cronos, the MHD output is now taken as an input to the CR transport modeling. We discuss the diffusion and drift behavior of Galactic cosmic rays using the example of different theories, and study the effects of CIRs on these transport processes. In particular, we point out the wide range of possible particle fluxes at a given point in space resulting from these different theories. The restriction of this variety by fitting the numerical results to spacecraft data will be the subject of the third paper of this series.

  15. The CoRoT satellite in flight : description and performance

    CERN Document Server

    Auvergne, M; Boisnard, L; Buey, J -T; Chaintreuil, S

    2009-01-01

    CoRoT is a space telescope dedicated to stellar seismology and the search for extrasolar planets. The mission is led by CNES in association with French laboratories and has a large international participation: the European Space Agency (ESA), Austria, Belgium and Germany contribute to the payload, and Spain and Brazil contribute to the ground segment. Development of the spacecraft, which is based on a PROTEUS low earth orbit recurrent platform, commenced in October 2000 and the satellite was launched on December 27th 2006. The instrument and platform characteristics prior to launch have been described in ESA publication (SP-1306) . In the present paper we detail the behaviour in flight, based on raw and corrected data. Five runs have been completed since January 2007. The data used here are essentially those acquired during the commissioning phase and from a long run which lasted 146 days, these enable us to give a complete overview of the instrument and platform behaviour for all environmental conditions. Th...

  16. The changing phases of extrasolar planet CoRoT-1b.

    Science.gov (United States)

    Snellen, Ignas A G; de Mooij, Ernst J W; Albrecht, Simon

    2009-05-28

    Hot Jupiters are a class of extrasolar planet that orbit their parent stars at very short distances. They are expected to be tidally locked, which can lead to a large temperature difference between their daysides and nightsides. Infrared observations of eclipsing systems have yielded dayside temperatures for a number of transiting planets. The day-night contrast of the transiting extrasolar planet HD 189733b was 'mapped' using infrared observations. It is expected that the contrast between the daysides and nightsides of hot Jupiters is much higher at visual wavelengths, shorter than that of the peak emission, and could be further enhanced by reflected stellar light. Here we report the analysis of optical photometric data obtained over 36 planetary orbits of the transiting hot Jupiter CoRoT-1b. The data are consistent with the nightside hemisphere of the planet being entirely black, with the dayside flux dominating the optical phase curve. This means that at optical wavelengths the planet's phase variation is just as we see it for the interior planets in the Solar System. The data allow for only a small fraction of reflected light, corresponding to a geometric albedo of <0.20.

  17. Mechanistic modeling of modular co-rotating twin-screw extruders.

    Science.gov (United States)

    Eitzlmayr, Andreas; Koscher, Gerold; Reynolds, Gavin; Huang, Zhenyu; Booth, Jonathan; Shering, Philip; Khinast, Johannes

    2014-10-20

    In this study, we present a one-dimensional (1D) model of the metering zone of a modular, co-rotating twin-screw extruder for pharmaceutical hot melt extrusion (HME). The model accounts for filling ratio, pressure, melt temperature in screw channels and gaps, driving power, torque and the residence time distribution (RTD). It requires two empirical parameters for each screw element to be determined experimentally or numerically using computational fluid dynamics (CFD). The required Nusselt correlation for the heat transfer to the barrel was determined from experimental data. We present results for a fluid with a constant viscosity in comparison to literature data obtained from CFD simulations. Moreover, we show how to incorporate the rheology of a typical, non-Newtonian polymer melt, and present results in comparison to measurements. For both cases, we achieved excellent agreement. Furthermore, we present results for the RTD, based on experimental data from the literature, and found good agreement with simulations, in which the entire HME process was approximated with the metering model, assuming a constant viscosity for the polymer melt.

  18. Disentangling planetary and stellar activity features in the CoRoT-2 light curve

    CERN Document Server

    Bruno, G; Almenara, J -M; Barros, S C C; Lanza, A F; Montalto, M; Boisse, I; Santerne, A; Lagrange, A -M; Meunier, N

    2016-01-01

    [Abridged] Context. Stellar activity is an important source of systematic errors and uncertainties in the characterization of exoplanets. Most of the techniques used to correct for this activity focus on an ad hoc data reduction. Aims. We have developed a software for the combined fit of transits and stellar activity features in high-precision long-duration photometry. Our aim is to take advantage of the modelling to derive correct stellar and planetary parameters, even in the case of strong stellar activity. Methods. We use an analytic approach to model the light curve. The code KSint, modified by adding the evolution of active regions, is implemented into our Bayesian modelling package PASTIS. The code is then applied to the light curve of CoRoT-2. The light curve is divided in segments to reduce the number of free parameters needed by the fit. We perform a Markov chain Monte Carlo analysis in two ways. In the first, we perform a global and independent modelling of each segment of the light curve, transits ...

  19. MOST detects corotating bright spots on the mid-O type giant $\\xi$ Persei

    CERN Document Server

    Ramiaramanantsoa, Tahina; Chené, André-Nicolas; Richardson, Noel D; Henrichs, Huib F; Desforges, Sébastien; Rowe, Jason F; Matthews, Jaymie M; Kuschnig, Rainer; Weiss, Werner W; Sasselov, Dimitar; Rucinski, Slavek M; Guenther, David B

    2014-01-01

    We have used the MOST (Microvariability and Oscillations of STars) microsatellite to obtain four weeks of contiguous high-precision broadband visual photometry of the O7.5III(n)((f)) star $\\xi$ Persei in November 2011. This star is well known from previous work to show prominent DACs (Discrete Absorption Components) on time-scales of about $2$ d from UV spectroscopy and NRP (Non Radial Pulsation) with one $(l =3)$ p-mode oscillation with a period of $3.5$ h from optical spectroscopy. Our MOST-orbit ($101.4$ min) binned photometry fails to reveal any periodic light variations above the $0.1$ mmag $3$-sigma noise level for periods of hours, while several prominent Fourier peaks emerge at the $1$ mmag level in the two-day period range. These longer-period variations are unlikely due to pulsations, including gravity modes. From our simulations based upon a simple spot model, we deduce that we are seeing the photometric modulation of several co-rotating bright spots on the stellar surface. In our model, the starti...

  20. Modeling interstellar pickup ion distributions in corotating interaction regions inside 1 AU

    Science.gov (United States)

    Chen, J. H.; Schwadron, N. A.; Möbius, E.; Gorby, M.

    2015-11-01

    We present a modeling study of interstellar pickup ion (PUI) distributions in corotating interaction regions (CIRs). We consider gradual compressions associated with CIRs formed when fast speed streams overtake slower streams in the inner heliosphere. For the analysis, we adopt a simplified magnetohydrodynamic model of a CIR. The Energetic Particle Radiation Environment Module, a parallelized particle numerical kinetic code, is used to model PUI distributions using the focused transport equation, including adiabatic cooling/heating, adiabatic focusing, and parallel and perpendicular diffusion. The continuous injection of PUIs is handled as a source term with a ring distribution in velocity space that is produced from the local neutral density obtained from a hot model of the interstellar neutral gas. The simulated distributions exhibit a harder spectrum in the compression region and a softer spectrum in the rarefaction region than that in undisturbed solar wind. As an additional result, a v-5 power law tail distribution above the PUI cutoff speed (a knee in the distribution) emerges for a particular velocity gradient in the CIR. The tail above the PUI cutoff is sensitive to the CIR velocity gradient, and in one observational case studied, this relationship adequately explains the observed spectrum from 2 to 4 times the solar wind speed. This suggests that the velocity gradient associated with the CIR formation can efficiently create a seed population of PUIs before a shock forms even without stochastic acceleration. Thus, local CIR compressions without shocks may play a significant role in the acceleration process as suggested previously.

  1. Identifying the upper atmosphere structure of the inflated hot sub-Neptune CoRoT-24b

    Science.gov (United States)

    Juvan, Ines; Lammer, Helmut; Erkaev, Nikolai V.; Fossati, Luca; Cubillos, Patricio E.; Guenther, Eike; Odert, Petra; Kislyakova, Kristina G.; Lendl, Monika

    2016-04-01

    The CoRoT satellite mission discovered two Neptune-type planets, CoRoT-24b and CoRoT-24c, with observed transit radii of ≈3.7REarth and ≈4.9REarth and masses of ≤5.7MEarth and ≈28MEarth, respectively. From the deduced low mean densities it can be expected that their planetary cores are most likely surrounded by H2 dominated envelopes. While having very similar radii, the outer planet CoRoT-24c is at least 4.9 times more massive than its neighbour, indicating that their atmospheres can be fundamentally different. Therefore, we have investigated the upper atmosphere structure and escape rates of these two planets. We applied a hydrodynamic upper atmosphere model including heating by absorption of stellar extreme ultraviolet and X-ray (XUV) radiation, under the assumption that the observed transit radius RT is produced by Rayleigh scattering and H2-H2 collision absorption in a pure hydrogen atmosphere. This corresponds to a pressure level near 1 bar. We find an unsustainably high hydrodynamic escape rate of 1.6 × 1011 g/s for the atmosphere of CoRoT-24b. If real, such high atmospheric escape would lead to substantial mass loss from the planetary atmosphere, shrinking it to ≈2.2REarth within ≈4 Myr, which is inconsistent with the old age of the system. The solution to this discrepancy is that the observed transit radius RT must be 30-60% larger than the actual planetary radius at the 1 bar pressure level. We suggest that the observed transit radius RT is produced by absorption through scattering processes due to high altitude clouds or hazes. The Kepler satellite has discovered similar close-in low-density Neptune-type planets. We propose that it is very likely that the observed transit radii for the vast majority of these planets also differ from their actual planetary radii at the 1 bar pressure level. This would introduce a systematic bias in the measured radii and has dramatic implications in the determination of the mass-radius relation and for planet

  2. 血清HE4、CP2检测对子宫内膜癌患者临床病理分子、肿瘤组织中增殖分子表达的评估价值%Assessment value of serum HE4 and CP2 contents for the expression of clinical pathological molecules and proliferation molecules in tumor tissue of patients with endometrial carcinoma

    Institute of Scientific and Technical Information of China (English)

    周哲; 蒋欣; 宋继成; 贾红燕

    2016-01-01

    目的:研究血清人附睾蛋白(HE4)、CP2含量对子宫内膜癌患者临床病理分子、肿瘤组织中增殖分子表达的评估价值.方法:选择2013年5月~2016年3月在我院确诊为子宫内膜癌的40例患者以及同期在我院体检的健康志愿者40例进行研究,收集血清标本并测定HE4、c-myc、ZEB1、CP2、sTn、CA125、CA199的含量,收集子宫内膜癌组织和癌旁组织并测定P53、E-cad、EpCAM、C-erbB-2、Ki-67、MACC1的含量.结果:子宫内膜癌患者血清中CP2和HE4的含量显著高于健康志愿者(P<0.05),FIGOⅢ~Ⅳ期、低分化、肌层受累超过1/2、宫颈受累及子宫内膜癌患者的血清HE4和CP2含量显著高于FIGO工~Ⅱ期、中高分化、肌层累及不足1/2、宫颈未受累及的子宫内膜癌患者(P<0.05);子宫内膜癌患者血清中CA125、CA199、c-myc、sTn、ZEB1的含量显著高于健康志愿者(P<0.05),且与血清HE4、CP2呈正相关;子宫内膜癌组织中P53、E-cad的含量显著低于癌旁组织(P<0.05),且与血清HE4、CP2呈负相关,EpCAM、C-erbB-2、Ki-67、MACC1的含量显著高于癌旁组织(P<0.05),且与血清HE4、CP2呈正相关.结论:子宫内膜癌患者的血清HE4、CP2含量异常升高,血清HE4、CP2能够评估肿瘤的临床病理情况以及肿瘤组织的增殖程度.

  3. NACE国际阴极保护技术(CP1,CP2,CP3)资格认证培训班

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    中国腐蚀与防护学会与美国腐蚀工程师国际协会(NACEInternational)合作,决定于2012年3月、5月、6月在北京举办NACE国际阴极保护技术资格认证培训班(CP1,CP2,CP3)。

  4. COPOLYMERIZATION OF ETHYLENE AND PROPYLENE WITH (CpCH2CH2CH=CH2)2MCl2 (M = Zr, Hf) AND Cp2ZrCl2 CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Hui Yao; Shi-jing Xiao

    2000-01-01

    (CpCH2CH2CH = CH2)2MCl2(M = Zr, Hf)/MAO and Cp2ZrCl2/MAO (Cp = cyclopentadienyl; MAO =methylaluminoxane) catalyst systems have been compared for ethylene copolymerization to investigate the influence of the ligand and transition metal on the polymerization activity and copolymer properties. For both CH2CH2CH=CH2 substituted catalysts the catalytic activity decreased with increasing propene concentration in the feed. The activity of the hafnocene catalyst was 6~8 times lower than that of the analogous zirconocene catalyst, 13C NMR analysis showed that the copolymer obtained using the unsubstituted catalyst Cp2ZrCl2 has greater incorporatien of propene than those produced by CH2CH2CH=CH2 substituted Zr and Hf catalysts. The melting point, crystallinity and the viscosity-average molecular weight of the copolymer decreased with an increase of propene concentration in the feed. Both CH2CH2CH =CH2 substituted Zr and Hf catalysts exhibit little or no difference in the melting point and crystallinity of the produced copolymers. However,there are significant differences between the two zirconocene catalysts. The copolymer produced by Cp2ZrCl2 catalyst have much lower Tm and Xc than those obtained with the (CpCH2CH2CH=CH2)2ZrCl2 catalyst. The density and molecular weight of the copolymer decreased in the order: (CpCH2CH2CH=CH2)2HfCl2>(CpCH2CH2CH=CH2)2ZrCl2>Cp2ZrCl2. The kinetic behavior of copolymerizaton with Hf catalyst was found to be different from that with Zr catalyst.

  5. Energetic electron precipitation in weak to moderate corotating interaction region-driven storms

    Science.gov (United States)

    Ødegaard, Linn-Kristine Glesnes; Tyssøy, Hilde Nesse; Søraas, Finn; Stadsnes, Johan; Sandanger, Marit Irene

    2017-03-01

    High-energy electron precipitation from the radiation belts can penetrate deep into the mesosphere and increase the production rate of NOx and HOx, which in turn will reduce ozone in catalytic processes. The mechanisms for acceleration and loss of electrons in the radiation belts are not fully understood, and most of the measurements of the precipitating flux into the atmosphere have been insufficient for estimating the loss cone flux. In the present study the electron flux measured by the NOAA POES Medium Energy Proton and Electron Detectors 0° and 90° detectors is combined together with theory of pitch angle diffusion by wave-particle interaction to quantify the electron flux lost below 120 km altitude. Using this method, 41 weak and moderate geomagnetic storms caused by corotating interaction regions during 2006-2010 are studied. The dependence of the energetic electron precipitation fluxes upon solar wind parameters and geomagnetic indices is investigated. Nine storms give increased precipitation of >˜750 keV electrons. Nineteen storms increase the precipitation of >˜300 keV electrons, but not the >˜750 keV population. Thirteen storms either do not change or deplete the fluxes at those energies. Storms that have an increase in the flux of electrons with energy >˜300 keV are characterized by an elevated solar wind velocity for a longer period compared to the storms that do not. Storms with increased precipitation of >˜750 keV flux are distinguished by higher-energy input from the solar wind quantified by the ɛ parameter and corresponding higher geomagnetic activity.

  6. Halting Migration: Numerical Calculations of Corotation Torques in the Weakly Nonlinear Regime

    Science.gov (United States)

    Duffell, Paul C.

    2015-06-01

    Planets in their formative years can migrate due to the influence of gravitational torques in the protoplanetary disk they inhabit. For low-mass planets in an isothermal disk, it is known that there is a strong negative torque on the planet due to its linear perturbation to the disk, causing fast inward migration. The current investigation demonstrates that in these same isothermal disks, for intermediate-mass planets, there is a strong positive nonlinear corotation torque due to the effects of gas being pulled through a gap on horseshoe orbits. For intermediate-mass planets, this positive torque can partially or completely cancel the linear (Type I) torque, leading to slower or outward migration, even in an isothermal disk. The effect is most significant for super-Earth and sub-Jovian planets, during the transition from a low-mass linear perturber to a nonlinear gap-opening planet, when the planet has opened a so-called “partial gap,” though the precise values of these transition masses depend sensitively on the disk model (density profile, viscosity, and disk aspect ratio). In this study, numerical calculations of planet-disk interactions calculate these torques explicitly, and scalings are empirically constructed for migration rates in this weakly nonlinear regime. These results find outward migration is possible for planets with masses in the range 20-100 {M}\\oplus , though this range depends on the disk model considered. In the disk models where torque reversal occurs, the critical planet-to-star mass ratio for torque reversal was found to have the robust scaling {q}{crit}\\propto \\sqrt{α }{(h/r)}3, where α is the dimensionless viscosity parameter and h/r is the disk aspect ratio.

  7. DO COROTATING INTERACTION REGION ASSOCIATED SHOCKS SURVIVE WHEN THEY PROPAGATE INTO THE HELIOSHEATH?

    Energy Technology Data Exchange (ETDEWEB)

    Provornikova, E.; Opher, M. [Astronomy Department, Boston University, Boston, MA 02215 (United States); Izmodenov, V. [Department of Air Mechanics and Gas Dynamics, Faculty of Mechanics and Mathematics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Toth, G., E-mail: eprovorn@bu.edu, E-mail: mopher@bu.edu, E-mail: izmod@iki.rssi.ru, E-mail: gtoth@umich.edu [Center for Space Environment Modeling, University of Michigan, Ann Arbor, MI 48109 (United States)

    2012-09-10

    During the solar minimum at the distance of 42-52 AU from the Sun, Voyager 2 observed recurrent sharp, shock-like increases in the solar wind speed that look very much like forward shocks (Lazarus et al.). The shocks were produced by corotating interaction regions (CIRs) that originated near the Sun. After the termination shock (TS) crossing in 2007, Voyager 2 entered the heliosheath and has been observing the plasma emanated during the recent solar minima. Measurements show high variable flow, but there were no shocks detected in the heliosheath. When CIR-driven shocks propagate to the outer heliosphere, their structure changes due to collision and merging processes of CIRs. In this Letter, we explore an effect of the merging of CIRs on the structure of CIR-associated shocks. We use a three-dimensional MHD model to study the outward propagation of the shocks with characteristics similar to those observed by Voyager 2 at {approx}45 AU (Lazarus et al. 1999). We show that due to merging of CIRs (1) reverse shocks disappear, (2) forward shocks become weaker due to interaction with rarefaction regions from preceding CIRs, and (3) forward shocks significantly weaken in the heliosheath. Merged CIRs produce compression regions in the heliosheath with small fluctuations of plasma parameters. Amplitudes of the fluctuations diminish as they propagate deeper in the sheath. We conclude that interaction of shocks and rarefaction regions could be one of the explanations, why shocks produced by CIRs are not observed in the heliosheath by Voyager 2 while they were frequently observed upstream the TS.

  8. CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk

    CERN Document Server

    Gillen, Edward; Terquem, Caroline; Bouvier, Jerome; Alencar, Silvia H P; Gandolfi, Davide; Stauffer, John; Cody, Ann Marie; Venuti, Laura; Almeida, Pedro Viana; Micela, Giuseppina; Favata, Fabio; Deeg, Hans J

    2016-01-01

    CoRoT 223992193 is the only known low-mass, pre-main sequence eclipsing binary that shows evidence of a circumbinary disk. The system displays complex photometric and spectroscopic variability over a range of timescales and wavelengths. Using two optical CoRoT runs, and infrared Spitzer 3.6 and 4.5 $\\mu$m observations (simultaneous with the second CoRoT run), we model the out-of-eclipse light curves. The large scale structure in both CoRoT light curves is consistent with the constructive and destructive interference of starspot signals at two slightly different periods. Using the stellar $v\\sin i$ 's, we infer different rotation periods: the primary is consistent with synchronisation and the secondary is slightly supersynchronous. Comparison of the raw data to the residuals of our spot model in colour-magnitude space indicates additional contributions consistent with variable dust emission and obscuration. We also identify short-duration flux dips preceding secondary eclipse in all three CoRoT and Spitzer ban...

  9. Corotation-driven magnetosphere-ionosphere coupling currents in Saturn’s magnetosphere and their relation to the auroras

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    Full Text Available We calculate the latitude profile of the equatorward-directed ionospheric Pedersen currents that are driven in Saturn’s ionosphere by partial corotation of the magnetospheric plasma. The calculation incorporates the flattened figure of the planet, a model of Saturn’s magnetic field derived from spacecraft flyby data, and angular velocity models derived from Voyager plasma data. We also employ an effective height-integrated ionospheric Pedersen conductivity of 1 mho, suggested by a related analysis of Voyager magnetic field data. The Voyager plasma data suggest that on the largest spatial scales, the plasma angular velocity declines from near-rigid corotation with the planet in the inner magnetosphere, to values of about half of rigid corotation at the outer boundary of the region considered. The latter extends to ~ 15–20 Saturn radii (RS in the equatorial plane, mapping along magnetic field lines to ~ 15° co-latitude in the ionosphere. We find in this case that the ionospheric Pedersen current peaks near the poleward (outer boundary of this region, and falls toward zero over ~ 5°–10° equator-ward of the boundary as the plasma approaches rigid corotation. The peak current near the poleward boundary, integrated in azimuth, is ~ 6 MA. The field-aligned current required for continuity is directed out of the ionosphere into the magnetosphere essentially throughout the region, with the current density peaking at ~ 10 nA m-2 at ~ 20° co-latitude. We estimate that such current densities are well below the limit requiring field-aligned acceleration of magnetospheric electrons in Saturn’s environment ( ~ 70 nAm-2, so that no significant auroral features associated with this ring of upward current is anticipated. The observed ultraviolet auroras at Saturn are also found to occur significantly closer to the pole (at ~ 10°–15° co-latitude, and show considerable temporal and local time variability, contrary

  10. Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

    Science.gov (United States)

    Leitzinger, M; Odert, P; Kulikov, Yu N; Lammer, H; Wuchterl, G; Penz, T; Guarcello, M G; Micela, G; Khodachenko, M L; Weingrill, J; Hanslmeier, A; Biernat, H K; Schneider, J

    2011-10-01

    We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a "Hot Neptune" nor a "Hot Uranus"-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects.

  11. Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

    Science.gov (United States)

    Leitzinger, M.; Odert, P.; Kulikov, Yu.N.; Lammer, H.; Wuchterl, G.; Penz, T.; Guarcello, M.G.; Micela, G.; Khodachenko, M.L.; Weingrill, J.; Hanslmeier, A.; Biernat, H.K.; Schneider, J.

    2011-01-01

    We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects. PMID:21969736

  12. Fundamental properties of Kepler and CoRoT targets: III. Tuning scaling relations using the first adiabatic exponent

    CERN Document Server

    Yıldız, M; Kayhan, C

    2016-01-01

    So called scaling relations have the potential to reveal the mass and radius of solar-like oscillating stars, based on oscillation frequencies. In derivation of these relations, it is assumed that the first adiabatic exponent at the surface (Gamma_1s) of such stars is constant. However, by constructing interior models for the mass range 0.8-1.6 Msun, we show that Gamma_1s is not constant at stellar surfaces for the effective temperature range with which we deal. Furthermore, the well-known relation between large separation and mean density also depends on Gamma_1s. Such knowledge is the basis for our aim of modifying scaling relations. There are significant differences between masses and radii found from modified and conventional scaling relations. However, comparison of predictions of these relations with the non-asteroseismic observations of Procyon A reveals that new scaling relations are effective in determining the mass and radius of stars. In the present study, solar-like oscillation frequencies of 89 t...

  13. Significance of serum CP2 and anti-idiotypic mAb 6B11Ab2 in patients with ovarian tumor%卵巢肿瘤患者血清CP2及抗独特型mAb 6B11Ab2的检测意义

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    目的探讨应用卵巢癌抗原CP2及卵巢癌抗独特型单克隆抗体6B11 Ab2进行血清中相关抗体检测的可行性及临床应用价值. 方法应用ELISA法对95例恶性卵巢肿瘤、 40例良性卵巢肿瘤及9例子宫内膜异位症患者血清进行卵巢癌相关抗原及抗体的检测, 并以50例正常女性为对照. 结果非粘液性卵巢上皮癌抗原阳性率为100%,抗体阳性率为66.7%,高于粘液性卵巢上皮癌、非上皮性卵巢恶性肿瘤及生殖系统其他恶性肿瘤,并且明显高于卵巢良性肿瘤(P<0.01). 结论卵巢癌相关抗原及抗体的检测对临床诊断及辅助鉴别诊断有一定实用价值.

  14. Seventy new non-eclipsing BEER binaries discovered in CoRoT lightcurves and confirmed by RVs from AAOmega

    Science.gov (United States)

    Tal-Or, Lev; Faigler, Simchon; Mazeh, Tsevi

    2015-09-01

    We applied the BEER algorithm to the CoRoT lightcurves from the first five LRc fields and identified 481 non-eclipsing BEER candidates with periodic lightcurve modulations and amplitudes of 0.5 - 87 mmag. Medium-resolution spectra of 281 candidates were obtained in a seven-night AAOmega radial-velocity (RV) campaign, with a precision of ˜ 1 km/s. The RVs confirmed the binarity of 70 of the BEER candidates, with periods of 0.3 - 10 days.

  15. VizieR Online Data Catalog: Planetary transit candidates in CoRoT SRc01 field (Erikson+, 2012)

    Science.gov (United States)

    Erikson, A.; Santerne, A.; Renner, S.; Barge, P.; Aigrain, S.; Alapini, A.; Almenara, J.-M.; Alonso, R.; Auvergne, M.; Baglin, A.; Benz, W.; Bonomo, A. S.; Borde, P.; Bouchy, F.; Bruntt, H.; Cabrera, J.; Carone, L.; Carpano, S.; Csizmadia, Sz.; Deleuil, M.; Deeg, H. J.; Diaz, R. F.; Dvorak, R.; Ferraz-Mello, S.; Fridlund, M.; Gandolfi, D.; Gazzano, J.-C.; Gillon, M.; Guenther, E. W.; Guillot, T.; Hatzes, A.; Hebrard, G.; Jorda, L.; Lammer, H.; Leger, A.; Llebaria, A.; Mayor, M.; Mazeh, T.; Moutou, C.; Ollivier, M.; Ofir, A.; Paetzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Regulo, C.; Rouan, D.; Samuel, B.; Schneider, J.; Shporer, A.; Tingley, B.; Udry, S.; Wuchterl, G.

    2012-04-01

    Among the acquired data, we analyzed those for 1269 sources in the chromatic bands and 5705 in the monochromatic band. Instrumental noise and the stellar variability were treated with several detrending tools, to which several transit-search algorithms were subsequently applied. Fifty-one sources were classified as planetary transit candidates and 26 were followed up with ground-based observations. Until now, no planet has been detected in the CoRoT data from the SRc01 field. (1 data file).

  16. Transiting exoplanets from the CoRoT space mission. XIII. CoRoT-13b: a dense hot Jupiter in transit around a star with solar metallicity and super-solar lithium content

    CERN Document Server

    Cabrera, J; Ollivier, M; Diaz, R F; Csizmadia, Sz; Aigrain, S; Alonso, R; Almenara, J -M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Carone, L; Carpano, S; Deleuil, M; Deeg, H J; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gazzano, J -C; Gillon, M; Guenther, E W; Guillot, T; Hatzes, A; Havel, M; Hebrard, G; Jorda, L; Leger, A; Llebaria, A; Lammer, H; Lovis, C; Mazeh, T; Moutou, C; Ofir, A; von Paris, P; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Tingley, B; Titz-Weider, R; Wuchterl, G

    2010-01-01

    We announce the discovery of the transiting planet CoRoT-13b. Ground based follow-up in CFHT and IAC80 confirmed CoRoT's observations. The mass of the planet was measured with the HARPS spectrograph and the properties of the host star were obtained analyzing HIRES spectra from the Keck telescope. It is a hot Jupiter-like planet with an orbital period of 4.04 days, 1.3 Jupiter masses, 0.9 Jupiter radii, and a density of 2.34 g cm-3. It orbits a G0V star with Teff=5945K, M*=1.09 Msun, R*=1.01 Rsun, solar metallicity, a lithium content of +1.45 dex, and an estimated age between 0.12 and 3.15 Gyr. The lithium abundance of the star is consistent with its effective temperature, activity level, and age range derived from the stellar analysis. The density of the planet is extreme for its mass. It implies the existence of an amount of heavy elements with a mass between about 140 and 300 Mearth.

  17. VARIATIONS OF THE MUON FLUX AT SEA LEVEL ASSOCIATED WITH INTERPLANETARY ICMEs AND COROTATING INTERACTION REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Augusto, C. R. A.; Kopenkin, V.; Navia, C. E.; Tsui, K. H.; Shigueoka, H. [Instituto de Fisica, Universidade Federal Fluminense, 24210-346, Niteroi, RJ (Brazil); Fauth, A. C.; Kemp, E.; Manganote, E. J. T. [Instituto de Fisica Gleb Wathagin, Universidade Estadual de Campinas, Campinas, SP (Brazil); Leigui de Oliveira, M. A. [Centro de Ciencias Naturais e Humanas da Universidade Federal do ABC, Santo Andre, SP (Brazil); Miranda, P.; Ticona, R.; Velarde, A. [Instituto de Investigaciones Fisicas, UMSA, La Paz Bolivia (United States)

    2012-11-10

    We present the results of an ongoing survey on the association between the muon flux variation at ground level (3 m above sea level) registered by the Tupi telescopes (Niteri-Brazil, 22.{sup 0}9S, 43.{sup 0}2W, 3 m) and the Earth-directed transient disturbances in the interplanetary medium propagating from the Sun (such as coronal mass ejections (CME), and corotating interaction regions (CIRs)). Their location inside the South Atlantic Anomaly region enables the muon telescopes to achieve a low rigidity of response to primary and secondary charged particles. The present study is primarily based on experimental events obtained by the Tupi telescopes in the period from 2010 August to 2011 December. This time period corresponds to the rising phase of solar cycle 24. The Tupi events are studied in correlation with data obtained by space-borne detectors (SOHO, ACE, GOES). Identification of interplanetary structures and associated solar activity was based on the nomenclature and definitions given by the satellite observations, including an incomplete list of possible interplanetary shocks observed by the CELIAS/MTOF Proton Monitor on the Solar and Heliospheric Observatory (SOHO) spacecraft. Among 29 experimental events reported in the present analysis, there are 15 possibly associated with the CMEs and sheaths, and 3 events with the CIRs (forward or reverse shocks); the origin of the remaining 11 events has not been determined by the satellite detectors. We compare the observed time (delayed or anticipated) of the muon excess (positive or negative) signal on Earth (the Tupi telescopes) with the trigger time of the interplanetary disturbances registered by the satellites located at Lagrange point L1 (SOHO and ACE). The temporal correlation of the observed ground-based events with solar transient events detected by spacecraft suggests a real physical connection between them. We found that the majority of observed events detected by the Tupi experiment were delayed in

  18. Examination of North-South symmetry in Saturn's sub-corotating Magnetosphere: Cassini

    Science.gov (United States)

    Smith, E. J.; Dougherty, M. K.

    2015-12-01

    We previously investigated Saturn's sub-corotating mass-loaded spiraling magnetosphere using observations of Bφ (the azimuthal magnetic field component) in14 identical Cassini orbits near midnight in the Southern hemisphere from 0° to -80 °latitude . The basic equation representing the Magnetospheric- Ionospheric- Interaction (M-I-A), developed by Hill (1979) for Jupiter and modified by Cowley and Bunce (2002) for Saturn, is: Ip = Σp (1- ω/Ωs). Ip is the Ionospheric Pedersen Current; G is obtained from ionospheric radius, Ri, colatitude, θi, and the planetary magnetic field, Bs; Σp is altitude-integrated Pedersen conductivity; ω and Ωs are the angular rotation rates of the magnetospheric field and of Saturn Kilometric Radiation, a proxy for the planetary field rotation. The relation should hold irrespective of how the mass originates an important consideration since plasma injections are frequently imposed on radial outflow from the inner magnetosphere and used to obtain ω. Ampere's law relates Ip (Ri, θi) to Bφ (r, θ, radial distance and colatitude). It has been found that I/G = A exp(-Bθi), an exponential dependence that was not predicted, and implies that A= Σp while the exponential yields (1- ω/Ωs) so ω(θi) is determined. The derived values of ω yield a quasi-linear function of equatorial distance or L. (This dependence and an alternative expression for Ip/G also imply that ionospheric neutrals rotate at the same rate as Bs). Σp varies between 7.5 and 1.1 mho and ω(L) also varies significantly orbit-to-orbit. These are temporal variations since the orbits are spatially identical. ω(L) has been compared with ω(L) in publications based on azimuthal rotation velocity, Vφ. Hill(1979) is used to study M*, the rate of mass outflow. The general approach above has now been applied to the Northern hemisphere and the same 14 orbits. We report on the important issue of North-South symmetries and asymmetries. .

  19. The potential role of NGC 205 in generating Andromeda's vast thin co-rotating plane of satellite galaxies

    CERN Document Server

    Angus, Garry W; Gentile, Gianfranco; Diaferio, Antonaldo

    2016-01-01

    The Andromeda galaxy is observed to have a system of two large dwarf ellipticals and ~13 smaller satellite galaxies that are currently co-rotating in a thin plane, in addition to 2 counter-rotating satellite galaxies. We explored the consistency of those observations with a scenario where the majority of the co-rotating satellite galaxies originated from a subhalo group, where NGC 205 was the host and the satellite galaxies occupied dark matter sub-subhalos. We ran N-body simulations of a close encounter between NGC 205 and M31. In the simulations, NGC 205 was surrounded by massless particles to statistically sample the distribution of the sub-subhalos expected in a subhalo that has a mass similar to NGC 205. We made Monte Carlo samplings and found that, using a set of reference parameters, the probability of producing a thinner distribution of sub-subhalos than the observed NGC 205 + 15 smaller satellites (thus including the 2 counter-rotators, but excluding M32) increased from <1e-8 for the initial distr...

  20. Models of red giants in the CoRoT asteroseismology fields combining asteroseismic and spectroscopic constraints

    CERN Document Server

    Lagarde, N; Eggenberger, P; Morel, T; Montalbán, J; Mosser, B; Rodrigues, T S; Girardi, L; Rainer, M; Poretti, E; Barban, C; Hekker, S; Kallinger, T; Valentini, M; Carrier, F; Hareter, M; Mantegazza, L; Elsworth, Y; Michel, E; Baglin, A

    2015-01-01

    Context. The availability of asteroseismic constraints for a large sample of red giant stars from the CoRoT and Kepler missions paves the way for various statistical studies of the seismic properties of stellar populations. Aims. We use the first detailed spectroscopic study of 19 CoRoT red-giant stars (Morel et al 2014) to compare theoretical stellar evolution models to observations of the open cluster NGC 6633 and field stars. Methods. In order to explore the effects of rotation-induced mixing and thermohaline instability, we compare surface abundances of carbon isotopic ratio and lithium with stellar evolution predictions. These chemicals are sensitive to extra-mixing on the red-giant branch. Results. We estimate mass, radius, and distance for each star using the seismic constraints. We note that the Hipparcos and seismic distances are different. However, the uncertainties are such that this may not be significant. Although the seismic distances for the cluster members are self consistent they are somewhat...

  1. Comparison of the One-electron Oxidations of CO-Bridged vs Unbridged Bimetallic Complexes: Electron-transfer Chemistry of Os2Cp2(CO)4 and Os2Cp*2(μ-CO)2(CO)2 (Cp = η5-C5H5, Cp* = η5-C5Me5)

    Energy Technology Data Exchange (ETDEWEB)

    Laws, Derek R.; Bullock, R. Morris; Lee, Richmond; Huang, Kuo-Wei; Geiger, William J.

    2014-09-22

    The one-electron oxidations of two dimers of half-sandwich osmium carbonyl complexes have been examined by electrochemistry, spectro-electrochemistry, and computational methods. The all-terminal carbonyl complex Os2Cp2(CO)4 (1, Cp = η5-C5H5) undergoes a reversible one-electron anodic reaction at E1/2 = 0.41 V vs ferrocene in CH2Cl2/0.05 M [NBu4][B(C6F5)4], giving a rare example of a metal-metal bonded radical cation unsupported by bridging ligands. The IR spectrum of 1+ is consistent with an approximately 1:1 mixture of anti and gauche structures for the 33 e- radical cation in which it has retained all-terminal bonding of the CO ligands. DFT calculations, including orbital-occupancy-perturbed Mayer bond-order analyses, show that the HOMOs of anti-1 and gauche-1 are metal-ligand delocalized. Removal of an electron from 1 has very little effect on the Os-Os bond order, accounting for the resistance of 1+ to heterolytic cleavage. The Os-Os bond distance is calculated to decrease by 0.10 Å and 0.06 Å as a consequence of one-electron oxidation of anti-1 and gauche-1, respectively. The CO-bridged complex Os2Cp*2(μ-CO)2(CO)2 (Cp* = η5-C5Me5), trans-2, undergoes a more facile oxidation, E1/2 = - 0.11 V, giving a persistent radical cation shown by solution IR analysis to preserve its bridged-carbonyl structure. However, ESR analysis of frozen solutions of 2+ is interpreted in terms of the presence of two isomers, most likely anti-2+ and trans-2+, at low temperature. Calculations show that the HOMO of trans-2 is highly delocalized over the metal-ligand framework, with the bridging carbonyls accounting for about half of the orbital makeup. The Os-Os bond order again changes very little with removal of an electron, and the Os-Os bond length actually undergoes minor shortening. Calculations suggest that the second isomer of 2+ has both the trans CO-bridged and the anti all-terminal CO structures. DRL and WEG acknowledge the support of the National Science Foundation under

  2. Characterisation of boundary layer turbulent processes by the Raman lidar BASIL in the frame of HD(CP)2 Observational Prototype Experiment

    Science.gov (United States)

    Di Girolamo, Paolo; Cacciani, Marco; Summa, Donato; Scoccione, Andrea; De Rosa, Benedetto; Behrendt, Andreas; Wulfmeyer, Volker

    2017-01-01

    Measurements carried out by the University of Basilicata Raman lidar system (BASIL) are reported to demonstrate the capability of this instrument to characterise turbulent processes within the convective boundary layer (CBL). In order to resolve the vertical profiles of turbulent variables, high-resolution water vapour and temperature measurements, with a temporal resolution of 10 s and vertical resolutions of 90 and 30 m, respectively, are considered. Measurements of higher-order moments of the turbulent fluctuations of water vapour mixing ratio and temperature are obtained based on the application of autocovariance analyses to the water vapour mixing ratio and temperature time series. The algorithms are applied to a case study (11:30-13:30 UTC, 20 April 2013) from the High Definition Clouds and Precipitation for Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE), held in western Germany in the spring 2013. A new correction scheme for the removal of the elastic signal crosstalk into the low quantum number rotational Raman signal is applied. The noise errors are small enough to derive up to fourth-order moments for both water vapour mixing ratio and temperature fluctuations.To the best of our knowledge, BASIL is the first Raman lidar with a demonstrated capability to simultaneously retrieve daytime profiles of water vapour turbulent fluctuations up to the fourth order throughout the atmospheric CBL. This is combined with the capability of measuring daytime profiles of temperature fluctuations up to the fourth order. These measurements, in combination with measurements from other lidar and in situ systems, are important for verifying and possibly improving turbulence and convection parameterisation in weather and climate models at different scales down to the grey zone (grid increment ˜ 1 km; Wulfmeyer et al., 2016).For the considered case study, which represents a well-mixed and quasi-stationary CBL, the mean boundary layer height is found to

  3. CoRoT\\,102699796, the first metal-poor Herbig Ae pulsator: a hybrid $\\delta$ Sct-$\\gamma$ Dor variable?

    CERN Document Server

    Ripepi, V; Di Criscienzo, M; Catanzaro, G; Palla, F; Marconi, M; Ventura, P; Neiner, C; Catala, C; Bernabei, S

    2011-01-01

    We present the analysis of the time series observations of CoRoT\\,102699796 obtained by the CoRoT satellite that show the presence of five independent oscillation frequencies in the range 3.6-5 c/d. Using spectra acquired with FLAMES@VLT, we derive the following stellar parameters: spectral type F1V, T$_{\\rm eff}$=7000$\\pm$200 K, log(g)=$3.8\\pm0.4$, [M/H]=$-1.1\\pm0.2$, $v$sin$i$=$50\\pm5$ km/s, L/L$_{\\odot}$=21$^{+21}_{-11}$. Thus, for the first time we report the existence of a metal poor, intermediate-mass PMS pulsating star. Ground-based and satellite data are used to derive the spectral energy distribution of CoRoT\\,102699796 extending from the optical to mid-infrared wavelengths. The SED shows a significant IR excess at wavelengths greater than $\\sim5 \\mu$. We conclude that CoRoT\\,102699796 is a young Herbig Ae (F1Ve) star with a transitional disk, likely associated to the HII region [FT96]213.1-2.2. The pulsation frequencies have been interpreted in the light of the non-radial pulsation theory, using the...

  4. Identifying the `true' radius of the hot sub-Neptune CoRoT-24b by mass-loss modelling

    Science.gov (United States)

    Lammer, H.; Erkaev, N. V.; Fossati, L.; Juvan, I.; Odert, P.; Cubillos, P. E.; Guenther, E.; Kislyakova, K. G.; Johnstone, C. P.; Lüftinger, T.; Güdel, M.

    2016-09-01

    For the hot exoplanets CoRoT-24b and CoRoT-24c, observations have provided transit radii RT of 3.7 ± 0.4R⊕ and 4.9 ± 0.5R⊕, and masses of ≤5.7M⊕ and 28 ± 11M⊕, respectively. We study their upper atmosphere structure and escape applying an hydrodynamic model. Assuming RT ≈ RPL, where RPL is the planetary radius at the pressure of 100 mbar, we obtained for CoRoT-24b unrealistically high thermally driven hydrodynamic escape rates. This is due to the planet's high temperature and low gravity, independent of the stellar EUV flux. Such high escape rates could last only for high altitude hazes/clouds possibly extinct the light at RT. Our analysis constraints also the planet's mass to be 5-5.7M⊕. For CoRoT-24c, RPL and RT lie too close together to be distinguished in the same way. Similar differences between RPL and RT may be present also for other hot, low-density sub-Neptunes.

  5. The Comparison of Water Absorption Analysis between Counterrotating and Corotating Twin-Screw Extruders with Different Antioxidants Content in Wood Plastic Composites

    Directory of Open Access Journals (Sweden)

    Mohd Hafizuddin Ab Ghani

    2011-01-01

    Full Text Available Water absorption is a major concern for natural fibers as reinforcement in wood plastic composites (WPCs. This paper presents a study on the comparison analysis of water absorption between two types of twin-screw extruders, namely, counterrotating and corotating with presence of variable antioxidants content. Composites of mixed fibres between rice husk and saw dust with recycled high-density polyethylene (rHDPE were prepared with two different extruder machines, namely, counterrotating and corotating twin screw, respectively. The contents of matrix (30 wt% and fibres (62 wt% were mixed with additives (8 wt% and compounded using compounder before extruded using both of the machines. Samples were immersed in distilled water according to ASTM D 570-98. From the study, results indicated a significant difference among samples extruded by counterrotating and corotating twin-screw extruders. The counterrotating twin-screw extruder gives the smallest value of water absorption compared to corotating twin-screw extruder. This indicates that the types of screw play an important role in water uptake by improving the adhesion between natural fillers and the polymer matrix.

  6. BEER Analysis of Kepler and CoRoT Light Curves III. Sixty New Non-Eclipsing BEER Binaries Discovered in CoRoT Light Curves Confirmed by RVs from AAOmega

    Science.gov (United States)

    Tal-Or, L.; Faigler, S.; Mazeh, T.

    2015-07-01

    We have applied the BEER algorithm (Faigler& Mazeh 2011) to the CoRoT white-light curves from the first five LRc fields. We have found 491 non-eclipsing BEER candidates with periodic photometric modulations and amplitudes of 0.5-80 mmag. Medium-resolution spectra of 281 candidates were obtained in a seven-night AAOmega radial-velocity (RV) campaign, with a precision of ˜1 km s-1. The RVs confirmed the binarity of at least 60 of the BEER candidates, with RV semi-amplitudes ranging from 6 to 115 km s-1, and periods from 0.3 to 10 days. We detected an F-type star that may possibly have a brown dwarf companion in a 0.7-day period orbit.

  7. Transiting exoplanets from the CoRoT space mission IX. CoRoT-6b: a transiting `hot Jupiter' planet in an 8.9d orbit around a low-metallicity star

    CERN Document Server

    Fridlund, M; Alonso, R; Deleuil, M; Gandolfi, D; Gillon, M; Bruntt, H; Alapini, A; Csizmadia, Sz; Guillot, T; Lammer, H; Aigrain, S; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Borde, P; Bouchy, F; Cabrera, J; Carone, L; Carpano, S; Deeg, H J; De la Reza, R; Dvorak, R; Erikson, A; Ferraz-Mello, S; Guenther, E; Gondoin, P; Hartog, R den; Hatzes, A; Jorda, L; Leger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Shporer, A; Stecklum, B; Tingley, B; Weingrill, J; Wuchterl, G

    2010-01-01

    The CoRoT satellite exoplanetary team announces its sixth transiting planet in this paper. We describe and discuss the satellite observations as well as the complementary ground-based observations - photometric and spectroscopic - carried out to assess the planetary nature of the object and determine its specific physical parameters. The discovery reported here is a `hot Jupiter' planet in an 8.9d orbit, 18 stellar radii, or 0.08 AU, away from its primary star, which is a solar-type star (F9V) with an estimated age of 3.0 Gyr. The planet mass is close to 3 times that of Jupiter. The star has a metallicity of 0.2 dex lower than the Sun, and a relatively high $^7$Li abundance. While thelightcurveindicatesamuchhigherlevelof activity than, e.g., the Sun, there is no sign of activity spectroscopically in e.g., the [Ca ] H&K lines.

  8. A 0.8-2.4 μm Transmission spectrum of the hot Jupiter CoRoT-1b

    Energy Technology Data Exchange (ETDEWEB)

    Schlawin, E.; Herter, T. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Zhao, M. [Department of Astronomy, Pennsylvania State University, University Park, PA 16802 (United States); Teske, J. K. [Astronomy Department, The University of Arizona, Tucson, AZ 85721 (United States)

    2014-03-01

    Hot Jupiters with brightness temperatures ≳2000 K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an observable signature of large optical to infrared transit depth ratios. Previous transmission spectra of very hot Jupiters have shown a lack of TiO and VO, but only in planets that also appear to lack temperature inversions. We measure the transmission spectrum of CoRoT-1b, a hot Jupiter that was predicted to have a temperature inversion potentially due to significant TiO and VO in its atmosphere. We employ the multi-object spectroscopy method using the SpeX and MORIS instruments on the Infrared Telescope Facility (IRTF) and the Gaussian process method to model red noise. By using a simultaneous reference star on the slit for calibration and a wide slit to minimize slit losses, we achieve transit depth precision of 0.03%-0.09%, comparable to the atmospheric scale height but detect no statistically significant molecular features. We combine our IRTF data with optical CoRoT transmission measurements to search for differences in the optical and near-infrared absorption that would arise from TiO/VO. Our IRTF spectrum and the CoRoT photometry disfavor a TiO/VO-rich spectrum for CoRoT-1b, suggesting that the atmosphere has another absorber that could create a temperature inversion or that the blackbody-like emission from the planet is due to a spectroscopically flat cloud, dust, or haze layer that smoothes out molecular features in both CoRoT-1b's emission and transmission spectra. This system represents the faintest planet hosting star (K = 12.2) with a measured planetary transmission spectrum.

  9. Fundamental Properties of Stars using Asteroseismology from Kepler & CoRoT and Interferometry from the CHARA Array

    CERN Document Server

    Huber, D; Bedding, T R; Brandão, I M; Piau, L; Maestro, V; White, T R; Bruntt, H; Casagrande, L; Molenda-Żakowicz, J; Aguirre, V Silva; Sousa, S G; Barclay, T; Burke, C J; Chaplin, W J; Christensen-Dalsgaard, J; Cunha, M S; De Ridder, J; Farrington, C D; Frasca, A; García, R A; Gilliland, R L; Goldfinger, P J; Hekker, S; Kawaler, S D; Kjeldsen, H; McAlister, H A; Metcalfe, T S; Miglio, A; Monteiro, M J P F G; Pinsonneault, M H; Schaefer, G H; Stello, D; Stumpe, M C; Sturmann, J; Sturmann, L; Brummelaar, T A ten; Thompson, M J; Turner, N; Uytterhoeven, K

    2012-01-01

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes and high-resolution spectroscopy we derive a full set of near model-independent fundamental properties for the sample. We first use these properties to test asteroseismic scaling relations for the frequency of maximum power (nu_max) and the large frequency separation (Delta_nu). We find excellent agreement within the observational uncertainties, and empirically show that simple estimates of asteroseismic radii for main-sequence stars are accurate to <~4%. We furthermore find good agreement of our measured effective temperatures with spectroscopic and photometric estimates with mean deviations for stars between T_ef...

  10. Detection of frequency spacings in the young O-type binary HD 46149 from CoRoT photometry

    CERN Document Server

    Degroote, P; Auvergne, M; Simon-Diaz, S; Aerts, C; Noels, A; Rainer, M; Hareter, M; Poretti, E; Mahy, L; Oreiro, R; Vuckovic, M; Smolders, K; Baglin, A; Baudin, F; Catala, C; Michel, E; Samadi, R

    2010-01-01

    Using the CoRoT space based photometry of the O-type binary HD46149, stellar atmospheric effects related to rotation can be separated from pulsations, because they leave distinct signatures in the light curve. This offers the possibility of characterising and exploiting any pulsations seismologically. Combining high-quality space based photometry, multi-wavelength photometry, spectroscopy and constraints imposed by binarity and cluster membership, the detected pulsations in HD46149 are analyzed and compared with those for a grid of stellar evolutionary models in a proof-of-concept approach. We present evidence of solar-like oscillations in a massive O-type star, and show that the observed frequency range and spacings are compatible with theoretical predictions. Thus, we unlock and confirm the strong potential of this seismically unexplored region in the HR diagram.

  11. The GTC exoplanet transit spectroscopy survey. III. No asymmetries in the transit of CoRoT-29b

    Science.gov (United States)

    Pallé, E.; Chen, G.; Alonso, R.; Nowak, G.; Deeg, H.; Cabrera, J.; Murgas, F.; Parviainen, H.; Nortmann, L.; Hoyer, S.; Prieto-Arranz, J.; Nespral, D.; Cabrera Lavers, A.; Iro, N.

    2016-05-01

    Context. The launch of the exoplanet space missions obtaining exquisite photometry from space has resulted in the discovery of thousands of planetary systems with very different physical properties and architectures. Among them, the exoplanet CoRoT-29b was identified in the light curves the mission obtained in summer 2011, and presented an asymmetric transit light curve, which was tentatively explained via the effects of gravity darkening. Aims: Transits of CoRoT-29b are measured with precision photometry, to characterize the reported asymmetry in their transit shape. Methods: Using the OSIRIS spectrograph at the 10-m GTC telescope, we perform spectro-photometric differential observations, which allow us to both calculate a high-accuracy photometric light curve, and a study of the color-dependence of the transit. Results: After careful data analysis, we find that the previously reported asymmetry is not present in either of two transits, observed in July 2014 and July 2015 with high photometric precisions of 300 ppm over 5 min. Due to the relative faintness of the star, we do not reach the precision necessary to perform transmission spectroscopy of its atmosphere, but we see no signs of color-dependency of the transit depth or duration. Conclusions: We conclude that the previously reported asymmetry may have been a time-dependent phenomenon, which did not occur in more recent epochs. Alternatively, instrumental effects in the discovery data may need to be reconsidered. Light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/589/A62

  12. The role of the [CpM(CO)2](-) chromophore in the optical properties of the [Cp2ThMCp(CO)2](+) complexes, where M = Fe, Ru and Os. A theoretical view.

    Science.gov (United States)

    Cantero-López, Plinio; Le Bras, Laura; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro

    2015-12-14

    The chemical bond between actinide and the transition metal unsupported by bridging ligands is not well characterized. In this paper we study the electronic properties, bonding nature and optical spectra in a family of [Cp2ThMCp(CO)2](+) complexes where M = Fe, Ru, Os, based on the relativistic two component density functional theory calculations. The Morokuma-Ziegler energy decomposition analysis shows an important ionic contribution in the Th-M interaction with around 25% of covalent character. Clearly, charge transfer occurs on Th-M bond formation, however the orbital term most likely represents a strong charge rearrangement in the fragments due to the interaction. Finally the spin-orbit-ZORA calculation shows the possible NIR emission induced by the [FeCp(CO)2](-) chromophore accomplishing the antenna effect that justifies the sensitization of the actinide complexes.

  13. Differential population studies using asteroseismology: solar-like oscillating giants in CoRoT fields LRc01 and LRa01

    CERN Document Server

    Miglio, A; Morel, T; Barbieri, M; Chaplin, W J; Girardi, L; Montalban, J; Noels, A; Valentini, M; Mosser, B; Baudin, F; Casagrande, L; Fossati, L; Aguirre, V Silva; Baglin, A

    2013-01-01

    Solar-like oscillating giants observed by the space-borne satellites CoRoT and Kepler can be used as key tracers of stellar populations in the Milky Way. When combined with additional photometric/spectroscopic constraints, the pulsation spectra of solar-like oscillating giant stars not only reveal their radii, and hence distances, but also provide well-constrained estimates of their masses, which can be used as proxies for the ages of these evolved stars. In this contribution we provide supplementary material to the comparison we presented in Miglio et al. (2013) between populations of giants observed by CoRoT in the fields designated LRc01 and LRa01.

  14. CoRoT's view on variable B8/9 stars: spots versus pulsations: Evidence for differential rotation in HD 174648

    CERN Document Server

    Degroote, P; Samadi, R; Aerts, C; Kurtz, D W; Noels, A; Miglio, A; Montalban, J; Bloemen, S; Baglin, A; Baudin, F; Catala, C; Michel, E; Auvergne, M

    2011-01-01

    Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision continuous measurements of the CoRoT space satellite, low amplitudes are more easily detected, making a study of this neglected region worthwhile. Aims. We collected a small sample of B stars observed by CoRoT to determine the origin of the different types of variability observed. Methods. We combine literature photometry and spectroscopy to measure the fundamental parameters of the stars in the sample, and compare asteroseismic modelling of the light curves with (differentially rotating) spotted star models. Results. We found strong evidence for the existence of spots and differential rotation in HD 174648, and formulated hypotheses for their origin. We show that the distinction between pulsations and rotational modulation is difficult to make solely based on the light curve, especially in slowly rotating stars.

  15. Differential population studies using asteroseismology: Solar-like oscillating giants in CoRoT fields LRc01 and LRa01

    Directory of Open Access Journals (Sweden)

    Casagrande L.

    2013-03-01

    Full Text Available Solar-like oscillating giants observed by the space-borne satellites CoRoT and Kepler can be used as key tracers of stellar populations in the Milky Way. When combined with additional photometric/spectroscopic constraints, the pulsation spectra of solar-like oscillating giant stars not only reveal their radii, and hence distances, but also provide well-constrained estimates of their masses, which can be used as proxies for the ages of these evolved stars. In this contribution we provide supplementary material to the comparison we presented in Miglio et al. (2013 between populations of giants observed by CoRoT in the fields designated LRc01 and LRa01.

  16. Coupled orbital and spin evolution of the CoRoT-7 two-planet system using a Maxwell viscoelastic rheology

    CERN Document Server

    Colucci, Adrián Rodríguez; Correia, Alexandre

    2016-01-01

    We investigate the orbital and rotational evolution of the CoRoT-7 two-planet system, assuming that the innermost planet behaves like a Maxwell body. We numerically resolve the coupled differential equations governing the instantaneous deformation of the inner planet together with the orbital motion of the system. We show that, depending on the relaxation time for the deformation of the planet, the orbital evolution has two distinct behaviours: for relaxation times shorter than the orbital period, we reproduce the results from classic tidal theories, for which the eccentricity is always damped. However, for longer relaxation times, the eccentricity of the inner orbit is secularly excited and can grow to high values. This mechanism provides an explanation for the present high eccentricity observed for CoRoT-7 b, as well as for other close-in super-Earths in multiple planetary systems.

  17. Coupled orbital and spin evolution of the CoRoT-7 two-planet system using a Maxwell viscoelastic rheology

    Science.gov (United States)

    Rodríguez, A.; Callegari, N.; Correia, A. C. M.

    2016-12-01

    We investigate the orbital and rotational evolution of the CoRoT-7 two-planet system, assuming that the innermost planet behaves like a Maxwell body. We numerically resolve the coupled differential equations governing the instantaneous deformation of the inner planet together with the orbital motion of the system. We show that, depending on the relaxation time for the deformation of the planet, the orbital evolution has two distinct behaviours: for relaxation times shorter than the orbital period, we reproduce the results from classic tidal theories, for which the eccentricity is always damped. However, for longer relaxation times, the eccentricity of the inner orbit is secularly excited and can grow to high values. This mechanism provides an explanation for the present high eccentricity observed for CoRoT-7 b, as well as for other close-in super-Earths in multiple planetary systems.

  18. CoRoT LRa02_E2_0121: Neptune-size planet candidate turns into a hierarchical triple system with a giant primary

    CERN Document Server

    Tal-Or, L; Mazeh, T; Bouchy, F; Moutou, C; Alonso, R; Gandolfi, D; Aigrain, S; Auvergne, M; Barge, P; Bonomo, A S; Borde, P; Deeg, H; Ferraz-Mello, S; Deleuil, M; Dvorak, R; Erikson, A; Fridlund, M; Gillon, M; Guenther, E W; Guillot, T; Hatzes, A; Jorda, L; Lammer, H; Leger, A; Llebaria, A; Ollivier, M; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Tsodikovich, Y; Wuchterl, G

    2011-01-01

    This paper presents the case of CoRoT LRa02_E2_0121, which was initially classified as a Neptune-size transiting-planet candidate on a relatively wide orbit of 36.3 days. Follow-up observations were performed with UVES, Sandiford, SOPHIE and HARPS. These observations revealed a faint companion in the spectra. To find the true nature of the system we derived the radial velocities of the faint companion using TODMOR - a two-dimensional correlation technique, applied to the SOPHIE spectra. Modeling the lightcurve with EBAS we discovered a secondary eclipse with a depth of ~0.07%, indicating a diluted eclipsing binary. Combined MCMC modeling of the lightcurve and the radial velocities suggested that CoRoT LRa02_E2_0121 is a hierarchical triple system with an evolved G-type primary and an A-type:F-type grazing eclipsing binary. Such triple systems are difficult to discover.

  19. YSOVAR II: Mapping YSO Inner Disk Structure in NGC 2264 with Simultaneous Spitzer and CoRoT Time Series Photometry

    Science.gov (United States)

    Stauffer, John; Morales-Calderon, Maria; Rebull, Luisa; Affer, Laura; Alencar, Sylvia; Allen, Lori; Barrado, David; Bouvier, Jerome; Calvet, Nuria; Carey, Sean; Carpenter, John; Ciardi, David; Covey, Kevin; D'Alessio, Paola; Espaillat, Catherine; Favata, Fabio; Flaccomio, Ettore; Forbrich, Jan; Furesz, Gabor; Hartman, Lee; Herbst, William; Hillenbrand, Lynne; Holtzman, Jon; Hora, Joe; Marchis, Franck; McCaughrean, Mark; Micela, Giusi; Mundt, Reinhard; Plavchan, Peter; Turner, Neal; Skrutzkie, Mike; Smith, Howard; Song, Inseok; Szentgyorgi, Andy; Terebey, Susan; Vrba, Fred; Wasserman, Lawrence; Watson, Alan; Whitney, Barbara; Winston, Elaine; Wood, Kenny

    2011-05-01

    We propose a simultaneous, continuous 30 day observation of the star forming region NGC2264 with Spitzer and CoRoT. NGC2264 is the only nearby, rich star-forming region which can be observed with CoRoT; it is by definition then the only nearby, rich star-forming region where a simultaneous Spitzer/CoRoT campaign is possible. Fortunately, the visibility windows for the two spacecraft overlap, allowing this program to be done in the Nov. 25, 2011 to Jan. 4, 2012 time period. For 10 days, we propose to map the majority of the cluster (a 35'x35' region) to a depth of 48 seconds per point, with each epoch taking 1.7 hours, allowing of order 12 epochs per day. For the other 20 days, we propose to obtaining staring-mode data for two positions in the cluster having a high density of cluster members. We also plan to propose for a variety of other ground and space-based data, most of which would also be simultaneous with the Spitzer and CoRoT observing. These data will allow us to address many astrophysical questions related to the structure and evolution of the disks of young stars and the interaction of those disks with the forming star. The data may also help inform models of planet formation since planets form and migrate through the pre-main sequence disks during the 0.5-5 Myr age range of stars in NGC2264. The data we collect will also provide an archive of the variability properties of young stars that is unmatched in its accuracy, sensitivity, cadence and duration and which therefore could inspire investigation of phenomena which we cannot now imagine. The CoRoT observations have been approved, contingent on approval of a simultaneous Spitzer observing program (this proposal).

  20. Inertia-gravity wave radiation from the merging of two co-rotating vortices in the f-plane shallow water system

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Norihiko, E-mail: nori@phys-h.keio.ac.jp [Department of Physics, Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kouhoku-ku, Yokohama, Kanagawa 223-8521 (Japan)

    2015-12-15

    Inertia-gravity wave radiation from the merging of two co-rotating vortices is investigated numerically in a rotating shallow water system in order to focus on cyclone–anticyclone asymmetry at different values of the Rossby number (Ro). A numerical study is conducted on a model using a spectral method in an unbounded domain to estimate the gravity wave flux with high accuracy. Continuous gravity wave radiation is observed in three stages of vortical flows: co-rotating of the vortices, merging of the vortices, and unsteady motion of the merged vortex. A cyclone–anticyclone asymmetry appears at all stages at smaller Ro (≤20). Gravity waves from anticyclones are always larger than those from cyclones and have a local maximum at smaller Ro (∼2) compared with that for an idealized case of a co-rotating vortex pair with a constant rotation rate. The source originating in the Coriolis acceleration has a key role in cyclone–anticyclone asymmetry in gravity waves. An additional important factor is that at later stages, the merged axisymmetric anticyclone rotates faster than the elliptical cyclone due to the effect of the Rossby deformation radius, since a rotation rate higher than the inertial cutoff frequency is required to radiate gravity waves.

  1. The tip of the iceberg: the frequency content of the δ Sct star HD 50844 from CoRoT space photometry

    Science.gov (United States)

    Poretti, E.; Mantegazza, L.; Rainer, M.; Uytterhoeven, K.; Michel, E.; Baglin, A.; Auvergne, M.; Catala, C.; Samadi, R.; Rodríguez, E.; Garrido, R.; Amado, P.; Martín-Ruiz, S.; Moya, A.; Suárez, J. C.; Baudin, F.; Zima, W.; Alvarez, M.; Mathias, P.; Paparó, M.; Pápics, P.; Plachy, E.

    2009-09-01

    It has been suggested that the detection of a wealth of very low amplitude modes in δ Sct stars was only a matter of signal-to-noise ratio. Access to this treasure, impossible from the ground, is one of the scientific aims of the space mission CoRoT, developed and operated by CNES. This work presents the results obtained on HD 50844: the 140,016 datapoints allowed us to reach the level of 10-5 mag in the amplitude spectra. The frequency analysis of the CoRoT timeseries revealed hundreds of terms in the frequency range 0-30 d-1. The initial guess that δ Sct stars have a very rich frequency content is confirmed. The spectroscopic mode identification gives theoretical support since very high-degree modes (up to = 14) are identified. We also prove that cancellation effects are not sufficient in removing the flux variations associated to these modes at the noise level of the CoRoT measurements. The ground-based observations indicate that HD 50844 is an evolved star that is slightly underabundant in heavy elements, located on the Terminal Age Main Sequence. The predominant term (f1 = 6.92 d-1) has been identified as the fundamental radial mode combining ground-based photometric and spectroscopic data.

  2. The tip of the iceberg: the frequency content of the Delta Sct star HD 50844 from CoRoT space photometry

    CERN Document Server

    Poretti, E; Rainer, M; Uytterhoeven, K; Michel, E; Baglin, A; Auvergne, M; Catala, C; Samadi, R; Rodríguez, E; Garrido, R; Amado, P; Martin-Ruiz, S; Moya, A; Suarez, C; Baudin, F; Zima, W; Alvarez, M; Mathias, P; Paparo, M; Papics, P; Plachy, E

    2009-01-01

    It has been suggested that the detection of a wealth of very low amplitude modes in Delta Sct stars was only a matter of signal--to--noise ratio. Access to this treasure, impossible from the ground, is one of the scientific aims of the space mission CoRoT, developed and operated by CNES. This work presents the results obtained on HD 50844: the 140,016 datapoints allowed us to reach the level of 10^{-5} mag in the amplitude spectra. The frequency analysis of the CoRoT timeseries revealed hundreds of terms in the frequency range 0--30 d^{-1}. The initial guess that Delta Sct stars have a very rich frequency content is confirmed. The spectroscopic mode identification gives theoretical support since very high--degree modes (up to ell=14) are identified. We also prove that cancellation effects are not sufficient in removing the flux variations associated to these modes at the noise level of the CoRoT measurements. The ground--based observations indicate that HD 50844 is an evolved star that is slightly underabunda...

  3. The thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 microns

    CERN Document Server

    Gillon, M; Barman, T; Miller, N; Demory, B -O; Deleuil, M; Montalban, J; Bouchy, F; Cameron, A Collier; Deeg, H J; Fortney, J J; Fridlund, M; Harrington, J; Magain, P; Moutou, C; Queloz, D; Rauer, H; Rouan, D; Schneider, J

    2009-01-01

    We report measurements of the thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 microns with the Spitzer Infrared Array Camera (IRAC). Our measured occultation depths are 0.510 +- 0.042 % and 0.41 +- 0.11 % at 4.5 and 8 microns, respectively. In addition to the CoRoT optical measurements, these planet/star flux ratios indicate a poor heat distribution to the night side of the planet and are in better agreement with an atmosphere free of temperature inversion layer. Still, the presence of such an inversion is not definitely ruled out by the observations and a larger wavelength coverage is required to remove the current ambiguity. Our global analysis of CoRoT, Spitzer and ground-based data confirms the large mass and size of the planet with slightly revised values (Mp = 3.47 +- 0.22 Mjup, Rp = 1.466 +- 0.044 Rjup). We find a small but significant offset in the timing of the occultation when compared to a purely circular orbital solution, leading to e cos(omega) = -0.00291 +- 0.00063 where e...

  4. CoRoT's view of newly discovered B-star pulsators: results for 358 candidate B pulsators from the initial run's exoplanet field data

    CERN Document Server

    Degroote, P; Ollivier, M; Miglio, A; Debosscher, J; Cuypers, J; Briquet, M; Montalban, J; Thoul, A; Noels, A; De Cat, P; Balaguer-Nuñez, L; Maceroni, C; Ribas, I; Auvergne, M; Baglin, A; Deleuil, M; Weiss, W; Jorda, L; Baudin, F; Samadi, R

    2009-01-01

    We search for new variable B-type pulsators in the CoRoT data assembled primarily for planet detection, as part of CoRoT's Additional Programme. We aim to explore the properties of newly discovered B-type pulsators from the uninterrupted CoRoT space-based photometry and to compare them with known members of the Beta Cep and slowly pulsating B star (SPB) classes. We developed automated data analysis tools that include algorithms for jump correction, light-curve detrending, frequency detection, frequency combination search, and for frequency and period spacing searches. Besides numerous new, classical, slowly pulsating B stars, we find evidence for a new class of low-amplitude B-type pulsators between the SPB and Delta Sct instability strips, with a very broad range of frequencies and low amplitudes, as well as several slowly pulsating B stars with residual excess power at frequencies typically a factor three above their expected g-mode frequencies. The frequency data we obtained for numerous new B-type pulsato...

  5. Regular frequency patterns in the young delta Scuti star HD 261711 observed by the CoRoT and MOST satellites

    CERN Document Server

    Zwintz, K; Guenther, D B; Ryabchikova, T; Baglin, A; Themessl, N; Barnes, T G; Matthews, J M; Auvergne, M; Bohlender, D; Chaintreuil, S; Kuschnig, R; Moffat, A F J; Rowe, J F; Rucinski, S M; Sasselov, D; Weiss, W W

    2013-01-01

    We concentrate on an asteroseismological study of HD 261711, a rather hot delta Scuti type pulsating member of the young open cluster NGC 2264 located at the blue border of the instability region. HD 261711 was discovered to be a pre-main sequence delta Scuti star using the time series photometry obtained by the MOST satellite in 2006. High-precision, time-series photometry of HD 261711 was obtained by the MOST and CoRoT satellites in 4 separate new observing runs that are put into context with the star's fundamental atmospheric parameters obtained from spectroscopy. With the new MOST data set from 2011/12 and the two CoRoT light curves from 2008 and 2011/12, the delta Scuti variability was confirmed and regular groups of frequencies were discovered. The two pulsation frequencies identified in the data from the first MOST observing run in 2006 are confirmed and 23 new delta Scuti-type frequencies were discovered using the CoRoT data. Weighted average frequencies for each group are related to l=0 and l=1 p-mod...

  6. Ageing of a space-based CCD: photometric performance development of the low Earth orbiting detectors of the CoRoT mission

    CERN Document Server

    Asensio-Torres, Ruben

    2016-01-01

    In this thesis we have analysed the time evolution of the photometric precision achieved by the space-based exoplanet-hunting mission CoRoT during its flight phase (2007-2012). This study of the noise level of CoRoT light curves has been based on a previous paper by Aigrain et al. 2009, where they found a gradual degradation of the photometric performance over time for the first 14 months of data. Here we have analysed the anti-center runs IRa01 (2007), LRa01 (2008), LRa03 (2010) and LRa06 (2012). The two first runs were studied by Aigrain as well, so we are able to compare our results. The two last runs allowed us to evaluate the trend of photometric degradation over more than 5 years. We obtain low observational point-to-point noise, although a factor 3 bigger than the source photon noise. We find effects showing the ageing of the CoRoT CCDs. On 2h time scales we notice a receding photometric performance, with a noise increase of about 2.1 times across the four analysed runs, corresponding to a 15% increase...

  7. Transiting exoplanets from the CoRoT space mission. XXI. CoRoT-19b: a low density planet orbiting an old inactive F9V-star

    DEFF Research Database (Denmark)

    Guenther, E. W.; Díaz, R. F.; Gazzano, J.-C.

    2012-01-01

    to the end of its main-sequence life. The host star has a mass M∗ = 1.21 ± 0.05  M⊙ and radius R∗ = 1.65  ±  0.04 R⊙. The planet has a mass of MP = 1.11 ± 0.06 MJup and radius of RP = 1.29  ± 0.03 RJup. The resulting bulk density is only ρ = 0.71  ± 0.06 g cm-3, which is much lower than that for Jupiter......Context. Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. These measurements indicate that planets of similar mass can have very different radii. For low-density planets......, it is generally assumed that they are inflated owing to their proximity to the host-star. To determine the causes of this inflation, it is necessary to obtain a statistically significant sample of planets with precisely measured masses and radii. Aims. The CoRoT space mission allows us to achieve a very high...

  8. Transiting exoplanets from the CoRoT space mission. XXI. CoRoT-19b: a low density planet orbiting an old inactive F9V-star

    DEFF Research Database (Denmark)

    Guenther, E. W.; Díaz, R. F.; Gazzano, J.-C.

    2012-01-01

    Context. Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. These measurements indicate that planets of similar mass can have very different radii. For low-density planets, it is gener......Context. Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. These measurements indicate that planets of similar mass can have very different radii. For low-density planets...... physical configurations mimicking a planetary transit signal, we determine the radius and mass of the planet by combining CoRoT photometry with high-resolution spectroscopy obtained with the echelle spectrographs SOPHIE, HARPS, FIES, and SANDIFORD. To improve the precision of its ephemeris and the epoch...... to the end of its main-sequence life. The host star has a mass M∗ = 1.21 ± 0.05  M⊙ and radius R∗ = 1.65  ±  0.04 R⊙. The planet has a mass of MP = 1.11 ± 0.06 MJup and radius of RP = 1.29  ± 0.03 RJup. The resulting bulk density is only ρ = 0.71  ± 0.06 g cm-3, which is much lower than that for Jupiter...

  9. A new code for quasi-equilibrium initial data of binary neutron stars: corotating, irrotational and slowly spinning systems

    CERN Document Server

    Tsokaros, Antonios; Rezzolla, Luciano

    2015-01-01

    We present the extension of our \\cocal~- Compact Object CALculator - code to compute general-relativistic initial data for asymmetric binary compact-star systems. We construct quasi-equilibrium initial data for spinning binaries and multiple coordinate systems are employed. The Isenberg-Wilson-Mathews formalism is adopted and the constraint equations are solved using the representation formula with a suitable choice of a Green's function. We validate the new code with solutions for equal-mass binaries and explore its capabilities for a wide range of compactnesses, from a white dwarf binary with compactness $\\sim 10^{-4}$, up to a highly relativistic neutron-star binary with compactness $\\sim 0.22$. We also present a comparison with corotating and irrotational quasi-equilibrium sequences from the spectral code \\lorene~\\cite{TG2002b} with different compactness, showing that the results from the two codes agree to a precision of the order of $0.05\\%$. Finally, we present equilibria for spinning configurations wi...

  10. Discovery of a magnetic field in the CoRoT hybrid B-type pulsator HD 43317

    CERN Document Server

    Briquet, M; Leroy, B; Pápics, P I

    2013-01-01

    A promising way of testing the impact of a magnetic field on internal mixing (core overshooting, internal rotation) in main-sequence B-type stars is to perform asteroseismic studies of a sample of magnetic pulsators. The CoRoT satellite revealed that the B3IV star HD 43317 is a hybrid SPB/beta Cep-type pulsator that has a wealth of pulsational constraints on which one can perform a seismic modelling, in particular, probing the extent of its convective core and mixing processes. Moreover, indirect indicators of a magnetic field in the star were observed: rotational modulation due to chemical or temperature spots and X-ray emission. Our goal was to directly investigate the field in HD 43317 and, if it is magnetic, to characterise it. We collected data with the Narval spectropolarimeter installed at TBL (T\\'elescope Bernard Lyot, Pic du Midi, France) and applied the least-squares deconvolution technique to measure the circular polarisation of the light emitted from HD 43317. We modelled the longitudinal field me...

  11. FUNDAMENTAL PROPERTIES OF STARS USING ASTEROSEISMOLOGY FROM KEPLER AND CoRoT AND INTERFEROMETRY FROM THE CHARA ARRAY

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.; Ireland, M. J.; Bedding, T. R.; Maestro, V.; White, T. R. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Brandao, I. M.; Sousa, S. G.; Cunha, M. S. [Centro de Astrofo Latin-Small-Letter-Dotless-I sica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, P-4150-762 Porto (Portugal); Piau, L. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48823-2320 (United States); Bruntt, H.; Aguirre, V. Silva; Christensen-Dalsgaard, J. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Casagrande, L. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, The Australian National University, ACT 2611 (Australia); Molenda-Zakowicz, J. [Astronomical Institute of the University of Wroclaw, ul. Kopernika 11, 51-622 Wroclaw (Poland); Barclay, T. [Bay Area Environmental Research Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Burke, C. J. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Chaplin, W. J. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); De Ridder, J. [Instituut voor Sterrenkunde, K. U. Leuven, B-3001 Leuven (Belgium); Farrington, C. D. [Center for High Angular Resolution Astronomy, Georgia State University, P.O. Box 3969, Atlanta, GA 30302 (United States); Frasca, A., E-mail: daniel.huber@nasa.gov [INAF Osservatorio Astrofisico di Catania, I-95123 Catania (Italy); and others

    2012-11-20

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes, and high-resolution spectroscopy, we derive a full set of near-model-independent fundamental properties for the sample. We first use these properties to test asteroseismic scaling relations for the frequency of maximum power ({nu}{sub max}) and the large frequency separation ({Delta}{nu}). We find excellent agreement within the observational uncertainties, and empirically show that simple estimates of asteroseismic radii for main-sequence stars are accurate to {approx}< 4%. We furthermore find good agreement of our measured effective temperatures with spectroscopic and photometric estimates with mean deviations for stars between T {sub eff} = 4600-6200 K of -22 {+-} 32 K (with a scatter of 97 K) and -58 {+-} 31 K (with a scatter of 93 K), respectively. Finally, we present a first comparison with evolutionary models, and find differences between observed and theoretical properties for the metal-rich main-sequence star HD 173701. We conclude that the constraints presented in this study will have strong potential for testing stellar model physics, in particular when combined with detailed modeling of individual oscillation frequencies.

  12. The effect of the high-speed stream following the corotating interaction region on the geomagnetic activities

    Directory of Open Access Journals (Sweden)

    S. Watari

    Full Text Available The high-speed stream following the corotating interaction regions (CIRs was analyzed. As a result of the analysis, it is found that the geomagnetic field is continuously disturbed in the high-speed stream in question. The geomagnetic disturbances with long duration recurred several rotations between December 1993 and June 1994. These disturbances were associated with a large recurrent coronal hole expanding from the south pole of the Sun. High-speed solar wind from this coronal hole was observed by the IMP-8 satellite during this period. However, the observed intensities of the geomagnetic disturbances were different for each recurrent period. This is explained by the seasonal effect. The disturbed geomagnetic condition continued in the high-speed stream after the passage of the CIRs. The long duration of these disturbances can be explained by the continuous energy input into the Earth's magnetosphere from the high-speed regions following the CIRs. This kind of long-duration geomagnetic disturbance in association with coronal holes has been observed in the declining phase of other solar cycles. The relation between the coronal-hole area and the maximum solar-wind velocity is not good for the well-developed large coronal hole analyzed here.

  13. An asteroseismic study of the O9V star HD 46202 from CoRoT space-based photometry

    CERN Document Server

    Briquet, M; Baglin, A; Nieva, M F; Degroote, P; Przybilla, N; Noels, A; Schiller, F; Vuckovic, M; Oreiro, R; Smolders, K; Auvergne, M; Baudin, F; Catala, C; Michel, E; Samadi, R

    2011-01-01

    The O9V star HD 46202, which is a member of the young open cluster NGC 2244, was observed by the CoRoT satellite in October/November 2008 during a short run of 34 days. From the very high-precision light curve, we clearly detect beta Cep-like pulsation frequencies with amplitudes of ~0.1 mmag and below. A comparison with stellar models was performed using a chi^2 as a measure for the goodness-of-fit between the observed and theoretically computed frequencies. The physical parameters of our best-fitting models are compatible with the ones deduced spectroscopically. A core overshooting parameter alpha_ov = 0.10 +- 0.05 pressure scale height is required. None of the observed frequencies are theoretically excited with the input physics used in our study. More theoretical work is thus needed to overcome this shortcoming in how we understand the excitation mechanism of pulsation modes in such a massive star. A similar excitation problem has also been encountered for certain pulsation modes in beta Cep stars recentl...

  14. CoRoT high-precision photometry of the B0.5 IV star HD 51756

    CERN Document Server

    Pápics, P I; Auvergne, M; Aerts, C; Degroote, P; Niemczura, E; Vu\\vcković, M; Smolders, K; Poretti, E; Rainer, M; Hareter, M; Baglin, A; Baudin, F; Catala, C; Michel, E; Samadi, R

    2011-01-01

    OB stars are important constituents for the ecology of the Universe, and there are only a few studies on their pulsational properties detailed enough to provide important feedback on current evolutionary models. Our goal is to analyse and interpret the behaviour present in the CoRoT light curve of the B0.5 IV star HD 51756 observed during the second long run of the space mission, and to determine the fundamental stellar parameters from ground-based spectroscopy gathered with the CORALIE and HARPS instruments after checking for signs of variability and binarity, thus making a step further in mapping the top of the Beta Cep instability strip. We compare the newly obtained high-resolution spectra with synthetic spectra of late O-type and early B-type stars computed on a grid of stellar parameters. We match the results with evolutionary tracks to estimate stellar parameters. We use various time series analysis tools to explore the nature of the variations present in the light curve. Additional calculations are ca...

  15. CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Mon

    CERN Document Server

    Desmet, M; Baudin, F; Harmanec, P; Lampens, P; Pacheco, E Janot; Briquet, M; Degroote, P; Neiner, C; Mathias, P; Poretti, E; Rainer, M; Uytterhoeven, K; Amado, P J; Valtier, J -C; Prsa, A; Maceroni, C; Aerts, C

    2009-01-01

    Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution \\'echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon. We derived new, accurate ephemerides for both the orbital motion (with a period of 11.113d) and the long-term, overall brightness variation (with a period of 416.9d) of this strongly interacting Be + G semi-detached binary. It is shown that this long-term variation must be due to attenuation of the total light by some variable circumbinary material. We derived the binary mass ratio $M_{\\rm G}/M_{\\rm B}$ = 0.17\\p0.03 based on the assumption that the G-type secondary fills its Roche lobe and rotates synchronously. Using this value of the mass ratio as well as the radial velocities of the G-star, we obtained a consistent light curve model and improved estimates of the stellar masses, radii, luminosities and effective temperatures. We demonstrate that the observed lines of the...

  16. Dynamic Young Stars and their Disks: A Temporal View of NGC 2264 with Spitzer and CoRoT*

    Directory of Open Access Journals (Sweden)

    Cody Ann Marie

    2014-01-01

    Full Text Available Variability is a signature feature of young stars. Among the well known light curve phenomena are periodic variations attributed to surface spots and irregular changes associated with accretion or circumstellar disk material. While decades of photometric monitoring have provided a framework for classifying young star variability, we still know surprisingly little about its underlying mechanisms and connections to the surrounding disks. In the past few years, dedicated photometric monitoring campaigns from the ground and space have revolutionized our view of young stars in the time domain. We present a selection of optical and infrared time series from several recent campaigns, highlighting the Coordinated Synoptic Investigation of NGC 2264 (“CSI 2264”– a joint30-day effort with the Spitzer, CoRoT, and MOST telescopes. The extraordinary photometric precision, high cadence, and long time baseline of these observations is now enabling correlation of variability properties at very different wavelengths, corresponding to locations from the stellar surface to the inner 0.1 AU of the disk. We present some results of the CSI 2264 program, including new classes of optical/infrared behavior. Further efforts to tie observed variability features to physical models will provide insights into the inner disk environment at a time when planet formation may be underway.

  17. On the Kinematics of a Corotating Relativistic Plasma Stream in the Perpendicular rotator Model of a Pulsar Magnetosphere

    Science.gov (United States)

    Chedia, O. V.; Kahniashvili, T. A.; Machabeli, G. Z.; Nanobashvili, I. S.

    1996-05-01

    An investigation of the kinematics of a rotating relativistic plasma stream in the perpendicular rotator model of the pulsar magnetosphere is presented. It is assumed that the plasma (ejected from the pulsar) moves along the pulsar magnetic field lines and also corotates with them. The field lines are considered to be radial straight lines, located in the plane which is perpendicular to the pulsar rotation axis. The necessity of taking particle inertia into account is discussed. It is argued that the “massless” (“force-free”) approximation cannot be used for the description of this problem. The frame selection is discussed and it is shown that it is convenient to discuss the problem in the noninertial frame of ZAMOs (Zero Angular Momentum Observers). The equation of motion and the exact set of equations describing the behaviour of a relativistic plasma stream in the pulsar magnetosphere is obtained. The possible relevance of this investigation for the understanding of the formation process of a pulsar magnetosphere is discussed.

  18. Differential asteroseismic study of seismic twins observed by CoRoT; Comparison of HD 175272 with HD 181420

    CERN Document Server

    Ozel, N; Dupret, M A; Bruntt, H; Barban, C; Deheuvels, S; Garc'\\ia, R A; Michel, E; Samadi, R; Baudin, F; Mathur, S; Régulo, C; Auvergne, M; Morel, P; Pichon, B

    2013-01-01

    The CoRoT short asteroseismic runs give us the opportunity to observe a large variety of late-type stars through their solar-like oscillations. We report the observation and modeling of the F5V star HD 175272. Our aim is to define a method for extracting as much information as possible from a noisy oscillation spectrum. We followed a differential approach that consists of using a well-known star as a reference to characterize another star. We used classical tools such as the envelope autocorrelation function to derive the global seismic parameters of the star. We compared HD 175272 with HD 181420 through a linear approach, because they appear to be asteroseismic twins. The comparison with the reference star enables us to substantially enhance the scientific output for HD 175272. First, we determined its global characteristics through a detailed seismic analysis of HD 181420. Second, with our differential approach, we measured the difference of mass, radius and age between HD 175272 and HD 181420. We have deve...

  19. Young [$\\alpha$/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?

    CERN Document Server

    Chiappini, C; Rodrigues, T S; Miglio, A; Montalban, J; Mosser, B; Girardi, L; Valentini, M; Noels, A; Morel, T; Minchev, I; Steinmetz, M; Santiago, B X; Schultheis, M; Martig, M; da Costa, L N; Maia, M A G; Prieto, C Allende; Peralta, R de Assis; Hekker, S; Themeßl, N; Kallinger, T; Garcia, R A; Mathur, S; Baudin, F; Beers, T C; Cunha, K; Harding, P; Holtzman, J; Majewski, S; Meszaros, Sz; Nidever, D; Pan, K; Schiavon, R P; Shetrone, M D; Schneider, D P; Stassun, K

    2015-01-01

    We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [alpha/Fe] abundance ratios (as determined from APOGEE spectra) with respect to Solar values. Their existence is not explained by standard chemical evolution models of the Milky Way, and shows that the chemical-enrichment history of the Galactic disc is more complex. We find similar stars in previously published samples for which isochrone-ages could be robustly obtained, although in smaller relative numbers, which could explain why these stars have not received prior attention. The young [alpha/Fe]-rich stars are much more numerous in the CoRoT-APOGEE (CoRoGEE) inner-field sample than in any other high-resolution sample available at present, as only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [$\\alpha$/Fe]-rich stars are not clearly thick-disc like, despite their rather large distances from the Galactic mid-plane. Our tentative interpretat...

  20. An analysis of the CoRoT-2 system: A young spotted star and its inflated giant planet

    CERN Document Server

    Guillot, Tristan

    2010-01-01

    Context: CoRoT-2b is one of the most anomalously large exoplanet known. Given its large mass, its large radius cannot be explained by standard evolution models. Interestingly, the planet's parent star is an active, rapidly rotating solar-like star with a large fraction (7 to 20%) of spots. Aims: We want to provide constraints on the properties of the star-planet system and understand whether the planet's inferred large size may be due to a systematic error on the inferred parameters, and if not, how it may be explained. Methods: We combine stellar and planetary evolution codes based on all available spectroscopic and photometric data to obtain self-consistent constraints on the system parameters. Results: We find no systematic error in the stellar modeling (including spots and stellar activity) that would yield the required ~10% reduction in size for the star and thus the planet. Two classes of solutions are found: the usual main sequence solution for the star yields for the planet a mass of 3.67+/-0.13 Mjup,...

  1. A 0.8-2.4 Micron Transmission Spectrum of the Hot Jupiter CoRoT-1b

    CERN Document Server

    Schlawin, Everett; Teske, Johanna K; Herter, Terry

    2014-01-01

    Hot Jupiters with brightness temperatures > ~2000K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an observable signature of large optical to infrared transit depth ratios. Previous transmission spectra of very hot Jupiters have shown a lack of TiO and VO, but only in planets that also appear to lack temperature inversions. We measure the transmission spectrum of CoRoT-1b, a hot Jupiter that was predicted to have a temperature inversion potentially due to significant TiO and VO in its atmosphere. We employ the multi-object spectroscopy (MOS) method using the SpeX and MORIS instruments on the Infrared Telescope Facility (IRTF) and the Gaussian Process method to model red noise. By using a simultaneous reference star on the slit for calibration and a wide slit to minimize slit losses, we achieve transit depth precision of 0.03% to 0.09%, comparable to the atmospheric scale heig...

  2. The optimization of Blister Disk geometry for mixing performance in co-rotating twin-screw extruder

    Science.gov (United States)

    Matsumoto, Koki; Kayamori, Natsuki; Tanaka, Tatsuya; Arao, Yoshihiko

    2015-05-01

    Extensional flow has been taken notice as the more efficient solution for improving the dispersion of nanocomposites than shear flow. One of the production processes of nanocomposites is melt extrusion with co-rotating twin-screw extruder (TSE) which is superior in terms of productivity and mixing performance. Then, we focused on "Blister Disk" which had many small holes for generating the extensional flow. However, the influences on the mixing performance by changing the geometry of Blister Disk have not been investigated as far as we know. Therefore, the objective of this study is the optimization of Blister Disk geometry (e.g. hole numbers, hole diameter and disk length) for improving the dispersion of nanocomposites. Primary, the extensional flow state was investigated at the Blister Disk with FEM analysis. Secondly, to validate the simulation results experimentally, the polypropylene reinforced multi-walled carbon nanotube (PP/CNT nanocomposite) was used as the model of nanocomposite, and the dispersion state of CNT was investigated by morphological observation. As the result of these experiments, the better dispersion state of CNT was obtained as total permeation area and shorter hole length of Blister Disk was smaller because extensional and shear stress were increased.

  3. Observations of corotating solar wind structures at radio sounding by signals of the Rosetta and Mars Express spacecraft

    Science.gov (United States)

    Efimov, A. I.; Lukanina, L. A.; Samoznaev, L. N.; Chashei, I. V.; Bird, M. K.; Pätzold, M.

    2016-05-01

    In the implementation of the space projects Rosetta and Mars Express, a large-scale series of experiments has been carried out on radio sounding circumsolar plasma by decimeter ( S-band) and centimeter ( X-band) signals of the Rosetta comet probe (from October 3 to October 31, 2010) and the Mars Express satellite of Mars (from December 25, 2010 to March 27, 2011). It was found that in the phase of ingress the spacecraft behind the Sun, the intensity of the frequency fluctuations increases in accordance with a power function whose argument is the solar offset distance of radio ray path, and when the spacecraft is removed from the Sun (the egress phase), frequency fluctuations are reduced. Periodic strong increases in the fluctuation level, exceeding by a factor of 3-12 the background values of this value determined by the regular radial dependences, are imposed on the regular dependences. It was found that increasing the fluctuations of radio waves alternates with the periodicity m × T or n × T, where m = 1/2, n = 1, and T is the synodic period of the Sun's rotation ( T ≈ 27 days). It was shown that the corotating structures associated with the interaction regions of different speed fluxes are formed in the area of solar wind acceleration and at distances of 6-20 solar radii already have a quasi-stationary character.

  4. Counterstreaming suprathermal electron events upstream of corotating shocks in the solar wind beyond approximately 2 AU: Ulysses

    Science.gov (United States)

    Gosling, J. T.; Bame, S. J.; Feldman, W. C.; Mccomas, D. J.; Phillips, J. L.; Goldstein, B. E.

    1993-01-01

    Enhanced fluxes of suprathermal electrons are commonly observed upstream of corotating forward and reverse shocks in the solar wind at heliocentric distances beyond approximately 2 AU by the Los Alamos plasma experiment on Ulysses. The average duration of these events, which are most intense immediately upstream from the shocks and which fade with increasing distance from them, is approximately 2.4 days near 5 AU. These events are caused by the leakage of shock-heated electrons into the upstream region. The upstream regions of these shocks face back toward the Sun along the interplanetary magnetic field, so these leaked electrons commonly counterstream relative to the normal solar wind electron heat flux. The observations suggest that conservation of magnetic moment and scattering typically limit the sunward propagation of these electrons as beams to field-aligned distances of approximately 15 AU. Although it seems unlikely that these shock-associated events are an important source of counterstreaming events near 1 AU, remnants of the backstreaming beams may contribute importantly to the diffuse solar wind halo electron population there.

  5. Characterization of Water Vapor Fluxes by the Raman Lidar System Basil and the Univeristy of Cologne Wind Lidar in the Frame of the HD(CP)2 Observational Prototype Experiment - Hope

    Science.gov (United States)

    Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Cacciani, Marco; Scoccione, Andrea; Schween, Jan H.

    2016-06-01

    Measurements carried out by the Raman lidar system BASIL and the University of Cologne wind lidar are reported to demonstrate the capability of these instruments to characterize water vapour fluxes within the Convective Boundary Layer (CBL). In order to determine the water vapour flux vertical profiles, high resolution water vapour and vertical wind speed measurements, with a temporal resolution of 1 sec and a vertical resolution of 15-90, are considered. Measurements of water vapour flux profiles are based on the application of covariance approach to the water vapour mixing ratio and vertical wind speed time series. The algorithms are applied to a case study (IOP 11, 04 May 2013) from the HD(CP)2 Observational Prototype Experiment (HOPE), held in Central Germany in the spring 2013. For this case study, the water vapour flux profile is characterized by increasing values throughout the CBL with lager values (around 0.1 g/kg m/s) in the entrainment region. The noise errors are demonstrated to be small enough to allow the derivation of water vapour flux profiles with sufficient accuracy.

  6. Prospective Out-of-ecliptic White-light Imaging of Interplanetary Corotating Interaction Regions at Solar Maximum

    Science.gov (United States)

    Xiong, Ming; Davies, Jackie A.; Li, Bo; Yang, Liping; Liu, Ying D.; Xia, Lidong; Harrison, Richard A.; Keiji, Hayashi; Li, Huichao

    2017-07-01

    Interplanetary corotating interaction regions (CIRs) can be remotely imaged in white light (WL), as demonstrated by the Solar Mass Ejection Imager (SMEI) on board the Coriolis spacecraft and Heliospheric Imagers (HIs) on board the twin Solar TErrestrial RElations Observatory (STEREO) spacecraft. The interplanetary WL intensity, due to Thomson scattering of incident sunlight by free electrons, is jointly determined by the 3D distribution of electron number density and line-of-sight (LOS) weighting factors of the Thomson-scattering geometry. The 2D radiance patterns of CIRs in WL sky maps look very different from different 3D viewpoints. Because of the in-ecliptic locations of both the STEREO and Coriolis spacecraft, the longitudinal dimension of interplanetary CIRs has, up to now, always been integrated in WL imagery. To synthesize the WL radiance patterns of CIRs from an out-of-ecliptic (OOE) vantage point, we perform forward magnetohydrodynamic modeling of the 3D inner heliosphere during Carrington Rotation CR1967 at solar maximum. The mixing effects associated with viewing 3D CIRs are significantly minimized from an OOE viewpoint. Our forward modeling results demonstrate that OOE WL imaging from a latitude greater than 60° can (1) enable the garden-hose spiral morphology of CIRs to be readily resolved, (2) enable multiple coexisting CIRs to be differentiated, and (3) enable the continuous tracing of any interplanetary CIR back toward its coronal source. In particular, an OOE view in WL can reveal where nascent CIRs are formed in the extended corona and how these CIRs develop in interplanetary space. Therefore, a panoramic view from a suite of wide-field WL imagers in a solar polar orbit would be invaluable in unambiguously resolving the large-scale longitudinal structure of CIRs in the 3D inner heliosphere.

  7. CoRoT's view of newly discovered B-star pulsators: results for 358 candidate B pulsators from the initial run's exoplanet field data

    Science.gov (United States)

    Degroote, P.; Aerts, C.; Ollivier, M.; Miglio, A.; Debosscher, J.; Cuypers, J.; Briquet, M.; Montalbán, J.; Thoul, A.; Noels, A.; De Cat, P.; Balaguer-Núñez, L.; Maceroni, C.; Ribas, I.; Auvergne, M.; Baglin, A.; Deleuil, M.; Weiss, W. W.; Jorda, L.; Baudin, F.; Samadi, R.

    2009-10-01

    Context: We search for new variable B-type pulsators in the CoRoT data assembled primarily for planet detection, as part of CoRoT's additional programme. Aims: We aim to explore the properties of newly discovered B-type pulsators from the uninterrupted CoRoT space-based photometry and to compare them with known members of the β Cep and slowly pulsating B star (SPB) classes. Methods: We developed automated data analysis tools that include algorithms for jump correction, light-curve detrending, frequency detection, frequency combination search, and for frequency and period spacing searches. Results: Besides numerous new, classical, slowly pulsating B stars, we find evidence for a new class of low-amplitude B-type pulsators between the SPB and δ Sct instability strips, with a very broad range of frequencies and low amplitudes, as well as several slowly pulsating B stars with residual excess power at frequencies typically a factor three above their expected g-mode frequencies. Conclusions: The frequency data we obtained for numerous new B-type pulsators represent an appropriate starting point for further theoretical analyses of these stars, once their effective temperature, gravity, rotation velocity, and abundances will be derived spectroscopically in the framework of an ongoing FLAMES survey at the VLT. The CoRoT space mission was developed and is operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. All frequency tables, including the identification of combination frequencies, are only available as online material. Frequency Tables are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/471 Bâtiment 121, 91405, Orsay Cedex, France. Postdoctoral Researcher, Fonds de la Recherche Scientifique - FNRS, Belgium. Postdoctoral Fellow of the Fund for Scientific Research

  8. Seventy-two new non-eclipsing BEER binaries discovered in CoRoT lightcurves and confirmed by RVs from AAOmega

    CERN Document Server

    Tal-Or, Lev; Mazeh, Tsevi

    2014-01-01

    We applied the BEER algorithm to the CoRoT lightcurves from the first five LRc fields and identified $491$ non-eclipsing BEER candidates with periodic lightcurve modulations and amplitudes of $0.5-80$ mmag. Medium-resolution spectra of $281$ candidates were obtained in a seven-night AAOmega radial-velocity (RV) campaign, with a precision of $\\sim1$ km/s. The RVs confirmed the binarity of $72$ of the BEER candidates, with periods of $0.3-10$ days.

  9. Major Geomagnetic Storms (Dst less than or equal to -100 nT) Generated by Corotating Interaction Regions

    Science.gov (United States)

    Richardson, I. G.; Webb, D. F.; Zhang, J.; Berdichevsky, B. D.; Biesecker, D. A.; Kasper, J. C.; Kataoka, R.; Steinberg, J. T.; Thompson, B. J.; Wu, C.-C.; Zhukov, A. N.

    2006-01-01

    Seventy-nine major geomagnetic storms (minimum Dst less than or equal to -100 nT) observed in 1996 to 2004 were the focus of a Living with a Star Coordinated Data-Analysis Workshop (CDAW) in March, 2005. In 9 cases, the storm driver appears to have been purely a corotating interaction region (CIR) without any contribution from coronal mass ejection-related material (interplanetary coronal mass ejections, ICMEs). These storms were generated by structures within CIRs located both before and/or after the stream interface that included persistently southward magnetic fields for intervals of several hours. We compare their geomagnetic effects with those of 159 CIRs observed during 1996 - 2005. The major storms form the extreme tail of a continuous distribution of CIR geoeffectiveness which peaks at Dst approx. -40 nT but is subject to a prominent seasonal variation of - 40 nT which is ordered by the spring and fall equinoxes and the solar wind magnetic field direction towards or away from the Sun. The O'Brien and McPherron [2000] equations, which estimate Dst by integrating the incident solar wind electric field and incorporating a ring current loss term, largely account for the variation in storm size. They tend to underestimate the size of the larger CIR-associated storms by Dst approx. 20 nT. This suggests that injection into the ring current may be more efficient than expected in such storms. Four of the nine major storms in 1996 - 2004 occurred during a period of less than three solar rotations in September - November, 2002, also the time of maximum mean IMF and solar magnetic field intensity during the current solar cycle. The maximum CIR-storm strength found in our sample of events, plus additional 23 probable CIR-associated Dst less than or equal to -100 nT storms in 1972 - 1995, is (Dst = -161 nT). This is consistent with the maximum storm strength (Dst approx. -180 nT) expected from the O'Brien and McPherron equations for the typical range of solar wind

  10. Solar-wind turbulence and shear: a superposed-epoch analysis of corotating interaction regions at 1 AU

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV.

    2009-01-01

    A superposed-epoch analysis of ACE and OMNI2 measurements is performed on 27 corotating interaction regions (CIRs) in 2003-2008, with the zero epoch taken to be the stream interface as determined by the maximum of the plasma vorticity. The structure of CIRs is investigated. When the flow measurements are rotated into the local-Parker-spiral coordinate system the shear is seen to be abrupt and intense, with vorticities on the order of 10{sup -5}-10{sup -4} sec{sup -1}. Converging flows perpendicular to the stream interface are seen in the local-Parker-spiral coordinate system and about half of the CIRs show a layer of divergent rebound flow away from the stream interface. Arguments indicate that any spreading of turbulence away from the region where it is produced is limited to about 10{sup 6} km, which is very small compared with the thickness of a CrR. Analysis of the turbulence across the CrRs is performed. When possible, the effects of discontinuities are removed from the data. Fluctuation amplitudes, the Alfvenicity, and the level of Alfvenic correlations all vary smoothly across the CrR. The Alfven ratio exhibits a decrease at the shear zone of the stream interface. Fourier analysis of 4.5-hr subintervals of ACE data is performed and the results are superposed averaged as an ensemble of realizations. The spectral slopes of the velocity, magnetic-field, and total-energy fluctuations vary smoothly across the CIR. The total-energy spectral slope is {approx} 3/2 in the slow and fast wind and in the CrRs. Analysis of the Elsasser inward-outward fluctuations shows a smooth transition across the CrR from an inward-outward balance in the slow wind to an outward dominance in the fast wind. A number of signatures of turbulence driving at the shear zone are sought (entropy change, turbulence amplitude, Alfvenicity, Alfven ratio, spectral slopes, in-out nature): none show evidence of driving of turbulence by shear.

  11. Multiple, distant (40°) in situ observations of a magnetic cloud and a corotating interaction region complex

    Science.gov (United States)

    Farrugia, C. J.; Berdichevsky, D. B.; Möstl, C.; Galvin, A. B.; Leitner, M.; Popecki, M. A.; Simunac, K. D. C.; Opitz, A.; Lavraud, B.; Ogilvie, K. W.; Veronig, A. M.; Temmer, M.; Luhmann, J. G.; Sauvaud, J. A.

    2011-06-01

    We report a comprehensive analysis of in situ observations made by Wind and the STEREO probes (STA, STB) of a complex interaction between a magnetic cloud (MC) and a corotating interaction region (CIR) occurring near the heliospheric current sheet (HCS) on November 19-21, 2007. The probes were separated by 0.7 AU (˜40∘) with a spread in heliographic latitudes (4.8,° 2.2,° and -0.4,° for STB, Wind and STA, respectively). We employ data from the MFI, SWE and 3DP instruments on Wind, and the PLASTIC and IMPACT suites on STEREO. STB, located east of Earth, observed a forward shock followed by signatures of a MC. The MC took the role of the HCS in that the polarity of the interplanetary magnetic field (IMF) on exit was the reverse of that on entry. A passage through a plasma sheet was observed. Along the Sun-Earth line Wind observed a stream interface (SI) between a forward and a reverse shock. A MC, compressed by the CIR, was entrained in this. STA, located 20° to the west of Earth, saw a MC which was not preceded by a shock. A SI trailed the transient. The shocks are examined using various methods and from this it is concluded that the forward shock at Wind—but not at STB—was driven by the MC. Examining the MC by Grad-Shafranov reconstruction, we find evidence of a double-flux rope structure at Wind and STA and possibly also at STB. The orientations are at variance with the notion of a large-scale flux tube being observed at the three spacecraft. We find consistency of this with the directional properties of the solar wind "strahl" electrons. We examine aspects of the geomagnetic response and find a double-dip storm corresponding to the two interplanetary triggers. The minimum Dst phase was prolonged and the geoeffects were intensified due to the interaction. We conclude that while the formation of compound streams is a common feature of interplanetary space, understanding their components when CIRs are involved is a complicated matter needing numerical

  12. Multiple, Distant (40 deg) in situ Observations of a Magnetic Cloud and a Corotating Interaction Region Complex

    Science.gov (United States)

    Farrugia, C. J.; Berdichevsky, D. B.; Moestl, C.; Galvin, A. B.; Leitner, M.; Popecki, M.; Simunac, K. D.; Opitz, A.; Lavraud, B.; Ogilvie, K.; Veronig, A.; Temmer, M.; Luhmann, J. G.; Sauvaud, J.

    2010-12-01

    We report a comprehensive analysis of in situ observations made by Wind and the STEREO probes (STA, STB) of a complex interaction between a magnetic cloud (MC) and a corotating interaction region (CIR) occurring near the heliospheric current sheet (HCS) on November 19-21, 2007. The probes were separated by 0.7 AU (~40 deg) with a spread in heliographic latitudes (4.8, 2.2, and -0.4 deg for STB, Wind and STA, respectively). We employ data from the MFI, SWE and 3DP instruments on Wind, and the PLASTIC and IMPACT suites on STEREO. STB, located east of Earth, observed a forward shock followed by signatures of a MC. The MC took the role of the HCS in that the polarity of the interplanetary magnetic field (IMF) on exit was the reverse of that on entry. A passage through a plasma sheet is observed. Along the Sun-Earth line Wind observed a stream interface (SI) between a forward and a reverse shock. A MC, compressed by the CIR, was entrained in this. STA, located 20 deg to the west of Earth, saw a MC which was not preceded by a shock. A SI trailed the transient. The shocks are examined using various methods and from this it is concluded that the forward shock at Wind - but not at STB - was driven by the MC. Examining the MC by Grad-Shafranov reconstruction, we find evidence of a double-flux rope structure at Wind and STA and possibly also at STB. The orientations are at variance with the notion of a large-scale flux tube being observed at the three spacecraft. We find consistency of this with the directional properties of the solar wind "strahl" electrons. We examine aspects of the geomagnetic response and find a double-dip storm corresponding to the two interplanetary triggers. The minimum Dst phase was prolonged and the geoffects were intensified due to the interaction. We conclude that while the formation of compound streams is a common feature of interplanetary space, understanding their components when CIRs are involved is a complicated matter needing numerical

  13. Solar-wind turbulence and shear: a superposed-epoch analysis of corotating interaction regions at 1 AU

    Energy Technology Data Exchange (ETDEWEB)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV.

    2009-01-01

    A superposed-epoch analysis of ACE and OMNI2 measurements is performed on 27 corotating interaction regions (CIRs) in 2003-2008, with the zero epoch taken to be the stream interface as determined by the maximum of the plasma vorticity. The structure of CIRs is investigated. When the flow measurements are rotated into the local-Parker-spiral coordinate system the shear is seen to be abrupt and intense, with vorticities on the order of 10{sup -5}-10{sup -4} sec{sup -1}. Converging flows perpendicular to the stream interface are seen in the local-Parker-spiral coordinate system and about half of the CIRs show a layer of divergent rebound flow away from the stream interface. Arguments indicate that any spreading of turbulence away from the region where it is produced is limited to about 10{sup 6} km, which is very small compared with the thickness of a CrR. Analysis of the turbulence across the CrRs is performed. When possible, the effects of discontinuities are removed from the data. Fluctuation amplitudes, the Alfvenicity, and the level of Alfvenic correlations all vary smoothly across the CrR. The Alfven ratio exhibits a decrease at the shear zone of the stream interface. Fourier analysis of 4.5-hr subintervals of ACE data is performed and the results are superposed averaged as an ensemble of realizations. The spectral slopes of the velocity, magnetic-field, and total-energy fluctuations vary smoothly across the CIR. The total-energy spectral slope is {approx} 3/2 in the slow and fast wind and in the CrRs. Analysis of the Elsasser inward-outward fluctuations shows a smooth transition across the CrR from an inward-outward balance in the slow wind to an outward dominance in the fast wind. A number of signatures of turbulence driving at the shear zone are sought (entropy change, turbulence amplitude, Alfvenicity, Alfven ratio, spectral slopes, in-out nature): none show evidence of driving of turbulence by shear.

  14. Suprathermal helium in corotating interaction regions: combined observations from SOHO/CELIAS/STOF and ACE/SWICS

    Science.gov (United States)

    Yu, J.; Berger, L.; Wimmer-Schweingruber, R.; Bochsler, P.; Klecker, B.; Hilchenbach, M.; Kallenbach, R.

    2017-02-01

    Context. Energetic particle enhancements that are associated with corotating interaction regions (CIRs) are typically believed to arise from the sunward propagation of particles that are accelerated by CIR-driven shocks beyond 1 AU. It is expected that these sunward-travelling particles will lose energy and scatter, resulting in a turnover of the energy spectra below 0.5 MeV/nuc. However, the turnover has not been observed so far, suggesting that the CIR-associated low-energy suprathermal ions are accelerated locally close to the observer. Aims: We investigate the variability of suprathermal particle spectra from CIR to CIR as well as their evolution and variation as the observer moves away from the rear shock or wave. Methods: Helium data in the suprathermal energy range from the Solar and Heliospheric Observatory/Charge, Element, and Isotope Analysis System/Suprathermal Time-of-Flight (SOHO/CELIAS/STOF) were used for the spectral analysis and were combined with data from the Advanced Composition Explorer/ Solar Wind Ion Composition Spectrometer (ACE/SWICS) in the solar wind energies. Results: We investigated sixteen events: nine clean CIR events, three CIR events with possible contamination from upstream ion events or solar energetic particles (SEPs), and four events that occurred during CIR periods that were dominated by SEPs. Six of the nine clean CIR events showed possible signs of a turnover between 10-40 keV/nuc in the fast solar wind that trails the compression regions. Three of them even showed this behaviour inside the compressed fast wind. The turnover part of the spectra became flatter and shifted from lower to higher energies with increasing connection distance to the reverse shock. The remaining three clean events showed continuous power-law spectra in both the compressed fast wind and fast wind regions, that is, the same behaviour as reported from previous observations. The spectra of the seven remaining events are more variable, that is, they show

  15. Asteroseismology for "\\`{a} la carte" stellar age-dating and weighing: Age and mass of the CoRoT exoplanet host HD 52265

    CERN Document Server

    Lebreton, Yveline

    2014-01-01

    In the context of CoRoT, Kepler, Gaia, TESS, and PLATO, precise and accurate stellar ages, masses and radii are of paramount importance. They are crucial to constrain scenarii of planetary formation and evolution.We aim at quantifying how detailed stellar modeling improves the accuracy and precision on age and mass of individual stars. We adopt a multifaceted approach where we examine how the number of observational constraints as well as the uncertainties on observations and on model input physics impact the age-dating and weighing. We modelled the exoplanet host-star HD52265, a MS, solar-like oscillator observed by CoRoT. We considered different sets of observational constraints (HR data, metallicity, seismic constraints). For each case, we determined the age, mass, and properties of HD52265 inferred from models, and quantified the impact of the models inputs. Our seismic analysis provides an age A=2.10-2.54 Gyr, a mass M=1.14-1.32 Msun, and a radius R=1.30-1.34 Rsun, which corresponds to uncertainties of 1...

  16. Atmospheric mass loss and evolution of short-period exoplanets: the examples of CoRoT-7b and Kepler-10b

    CERN Document Server

    Kurokawa, Hiroyuki

    2013-01-01

    Short-period exoplanets potentially lose envelope masses during their evolution because of atmospheric escape caused by the intense XUV radiation from their host stars. We develop a combined model of atmospheric mass loss calculation and thermal evolution calculation of a planet to simulate its evolution and explore the dependences on the formation history of the planet. Thermal atmospheric escape as well as the Roche-lobe overflow contributes to mass loss. The maximum initial planetary model mass depends primarily on the assumed evolution model of the stellar XUV luminosity. We adapt the model to CoRoT-7b and Kepler-10b to explore the evolution of both planets and the maximum initial mass of these planets. We take the recent X-ray observation of CoRoT-7 into account and exploring the effect of different XUV evolution models on the planetary initial mass. Our calculations indicate that both hot super Earths could be remnants of Jupiter mass gas planets.

  17. Doppler tomography of transiting exoplanets: A prograde, low-inclined orbit for the hot Jupiter CoRoT-11b

    CERN Document Server

    Gandolfi, Davide; Endl, Michael; Lanza, Antonino F; Damiani, Cilia; Alonso, Roi; Cochran, William D; Deleuil, Magali; Fridlund, Malcolm; Hatzes, Artie P; Guenther, Eike W

    2012-01-01

    We report the detection of the Doppler shadow of the transiting hot Jupiter CoRoT-11b. Our analysis is based on line-profile tomography of time-series, Keck/HIRES high-resolution spectra acquired during the transit of the planet. We measured a sky-projected, spin-orbit angle of 0.1 +/- 2.6 degrees, which is consistent with a very low-inclined orbit with respect to the stellar rotation axis. We refined the physical parameters of the system using a Markov chain Monte Carlo simultaneous fitting of the available photometric and spectroscopic data. An analysis of the tidal evolution of the system shows how the currently measured obliquity and its uncertainty translate into an initial absolute value of less than about 10 degrees on the zero-age main sequence, for an expected average modified tidal quality factor of the star Q'* > 4 x 10^6. This is indicative of an inward migration scenario that would not have perturbed the primordial low obliquity of CoRoT-11b. Taking into account the effective temperature and mass...

  18. Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satellite

    CERN Document Server

    Lefever, K; Morel, T; Aerts, C; Decin, L; Briquet, M

    2009-01-01

    We aim to determine the fundamental parameters of a sample of B stars with apparent visual magnitudes below 8 in the field-of-view of the CoRoT space mission, from high-resolution spectroscopy. We developed an automatic procedure for the spectroscopic analysis of B-type stars with winds, based on an extensive grid of FASTWIND model atmospheres. We use the equivalent widths and/or the line profile shapes of continuum normalized hydrogen, helium and silicon line profiles to determine the fundamental properties of these stars in an automated way. After thorough tests, both on synthetic datasets and on very high-quality, high-resolution spectra of B stars for which we already had accurate values of their physical properties from alternative analyses, we applied our method to 66 B-type stars contained in the ground-based archive of the CoRoT space mission. We discuss the statistical properties of the sample and compare them with those predicted by evolutionary models of B stars. Our spectroscopic results provide a...

  19. A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy

    CERN Document Server

    Morel, T; Auvergne, M; Alecian, G; Ghazaryan, S; Niemczura, E; Fossati, L; Lehmann, H; Hubrig, S; Ulusoy, C; Damerdji, Y; Rainer, M; Poretti, E; Borsa, F; Scardia, M; Schmid, V S; Van Winckel, H; De Smedt, K; Papics, P I; Gameiro, J F; Waelkens, C; Fagas, M; Kaminski, K; Dimitrov, W; Baglin, A; Michel, E; Dumortier, L; Fremat, Y; Hensberge, H; Jorissen, A; Van Eck, S

    2013-01-01

    The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar objects, the bright star HD 45975 was monitored for nearly two months by the CoRoT satellite. Independent analyses of the light curve provides evidence of monoperiodic variations with a frequency of 0.7572 c/d and a peak-to-peak amplitude of ~2800 ppm. Multisite, ground-based spectroscopic observations overlapping the CoRoT observations show the star to be a long-period, single-lined binary. Furthermore, with the notable exception of mercury, they reveal the same periodicity as in photometry in the line moments of chemical species exhibiting strong overabundances (e.g., Mn and Y). In contrast, lines of other elements do not show significant variations. As found in other HgMn stars, the pattern of variability consists in an absorption bump moving redwards across the line profiles. We argue that the photometric and spectroscopic changes are...

  20. The silicate and carbon-rich models of CoRoT-7b, Kepler-9d and Kepler-10b

    Institute of Scientific and Technical Information of China (English)

    Yan-Xiang Gong; Ji-Lin Zhout

    2012-01-01

    Possible bulk compositions of the super-Earth exoplanets CoRoT-7b,Kepler-9d,and Kepler-10b are investigated by applying a commonly used silicate model and a non-standard carbon model.Their internal structures are deduced using a suitable equation of state for the materials.The degeneracy problems of their compositions can be partly overcome,based