421 research outputs found

    Photophysical and Photochemical Studies of Tricarbonyl Rhenium(I) N-Heterocyclic Carbene Complexes Containing Azide and Triazolate Ligands

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    Rhenium(I) N-heterocyclic carbene (NHC) complexes of the type fac-[Re(CO)3(NHC)L] with either azide or triazolate ancillary ligands L and pyridyl or pyrimidyl substituted imidazolyl units have been prepared and structurally characterised, and their photophysical and photochemical properties studied. All of the complexes exhibit phosphorescent emission from triplet metal-to-ligand (3MCLT) excited states, typical of tricarbonyl Re(I) complexes, with the triazolate bound complexes having higher quantum yields and longer decay lifetimes compared to the azide bound complexes. The complexes containing pyridyl substituted imidazolyl units are photoreactive when dissolved in acetonitrile and undergo photochemical CO dissociation, the rate of which is significantly greater in the azide cf. triazolate complex. The photochemical mechanism of the azide/pyridyl complex was analysed and appears to give the same products, albeit with different ratios, to previously reported complexes where L is a halide. A reaction mechanism is proposed

    Bisectors of the HARPS Cross-Correlation-Function. The dependence on stellar atmospheric parameters

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    Bisectors of the HARPS cross-correlation function (CCF) can discern between planetary radial-velocity (RV) signals and spurious RV signals from stellar magnetic activity variations. However, little is known about the effects of the stellar atmosphere on CCF bisectors or how these effects vary with spectral type and luminosity class. Here we investigate the variations in the shapes of HARPS CCF bisectors across the HR diagram in order to relate these to the basic stellar parameters, surface gravity and temperature. We use archive spectra of 67 well studied stars observed with HARPS and extract mean CCF bisectors. We derive previously defined bisector measures (BIS, v_bot, c_b) and we define and derive a new measure called the CCF Bisector Span (CBS) from the minimum radius of curvature on direct fits to the CCF bisector. We show that the bisector measures correlate differently, and non-linearly with log g and T_eff. The resulting correlations allow for the estimation of log g and T_eff from the bisector measures. We compare our results with 3D stellar atmosphere models and show that we can reproduce the shape of the CCF bisector for the Sun.Comment: 13 pages, 20 figures. Accepted by A&

    Effet de l’association du haricot mungo sur le rendement du mil dans le Bassin arachidier, Sénégal

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    Ce numéro est constitué d’articles issus de la seconde édition des Rencontres Francophones sur les Légumineuses (RFL2) qui s’est tenu à Toulouse (France) les 17 et 18 octobre 2018.Agricultural production in Senegal is constrained by rainfall variability, persistent droughts, and low soilfertility. These constraints have decreased pearl millet yield in Senegal. Mungbean, a short-duration andrelatively drought-tolerant grain legume, is capable of improving soil fertility and increasing cropproduction. To investigate the potential of mungbean for increasing millet yield through intercropping,field experiments were conducted during the 2017 growing season in Bambey (Senegal). Intercroppingtreatments (sole millet (T1), sole mungbean (T2), and 23% (T3), 43% (T4), 47% (T5), 62% (T6), 125% (T7)et 164% (T8) of mungbean in sole millet) were laid out in a randomized complete block design andreplicated four times. Studied parameters included millet and mungbean yield parameters and combinedyields, normalized difference vegetation index (NDVI), canopy cover, and land equivalent ratio (LER).Intercropping (millet + mungbean) did not significantly increase millet biomass or grain yield comparedto millet alone. However, grain yield, number of pods and seeds, and plant height of mungbean plantswere significantly higher in T7 and T8 compared to other treatments. Combined yields were alsosignificantly (P ≤ 0.05) higher (up to 56%) under millet – mungbean intercropping. Similarly,intercropping significantly (P ≤ 0.05) increased LER and canopy cover (62%) over millet alone but notNDVI values. Results from this first-year suggest that intercropping with mungbean could sustain milletproduction through diversification of agricultural systems.La production agricole au Sénégal est limitée par la variabilité des précipitations, les sécheressespersistantes et la faible fertilité des sols. Ces contraintes ont contribué à la baisse des rendements dumil au Sénégal. Le haricot mungo, une légumineuse à graines à cycle court et relativement tolérante àla sécheresse, est capable d'améliorer la fertilité du sol et d’augmenter la production agricole. Pourétudier le potentiel du haricot mungo à augmenter le rendement du mil, des essais ont été menéspendant la saison culturale de 2017 à Bambey (Diourbel). Les systèmes d’association (mil seul (T1),haricot mungo seul (T2) et 23% (T3), 43% (T4), 47% (T5), 62% (T6), 125% (T7) et 164% (T8) de haricotmungo en association avec le mil) ont été disposés en blocs complets randomisés et répliqués quatrefois. Les données collectées comprennent les paramètres de rendement du mil et du haricot mungo etle rendement total en grains, l'indice de végétation par différence normalisée (NDVI), le taux decouverture du sol, et le land equivalent ratio (LER). L’association du mil avec le haricot mungo n'a passignificativement augmenté la biomasse et le rendement en grains du mil par rapport au mil seul.Cependant, le rendement en grains, le nombre de gousses et de graines, et la hauteur des plants deharicot mungo ont été significativement plus élevés pour les traitements T7 et T8 par rapport aux autrestraitements. Le rendement total en grains était aussi significativement (P ≤ 0,05) plus élevé (jusqu'à56%) en association. De même, l’association des cultures a entrainé des différences significatives pourle LER et le taux de couverture du sol (62%) mais pas pour les valeurs de NDVI. Les résultats de cettepremière année suggèrent que l'association avec le haricot mungo pourrait soutenir la production de milgrâce à la diversification des systèmes agricoles

    Patent citation analysis with Google

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    This is an accepted manuscript of an article published by Wiley-Blackwell in Journal of the Association for Information Science and Technology on 23/09/2015, available online: https://doi.org/10.1002/asi.23608 The accepted version of the publication may differ from the final published version.Citations from patents to scientific publications provide useful evidence about the commercial impact of academic research, but automatically searchable databases are needed to exploit this connection for large-scale patent citation evaluations. Google covers multiple different international patent office databases but does not index patent citations or allow automatic searches. In response, this article introduces a semiautomatic indirect method via Bing to extract and filter patent citations from Google to academic papers with an overall precision of 98%. The method was evaluated with 322,192 science and engineering Scopus articles from every second year for the period 1996–2012. Although manual Google Patent searches give more results, especially for articles with many patent citations, the difference is not large enough to be a major problem. Within Biomedical Engineering, Biotechnology, and Pharmacology & Pharmaceutics, 7% to 10% of Scopus articles had at least one patent citation but other fields had far fewer, so patent citation analysis is only relevant for a minority of publications. Low but positive correlations between Google Patent citations and Scopus citations across all fields suggest that traditional citation counts cannot substitute for patent citations when evaluating research

    Negative parental responses to coming out and family functioning in a sample of lesbian and gay young adults

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    Parental responses to youths' coming out (CO) are crucial to the subsequent adjustment of children and family. The present study investigated the negative parental reaction to the disclosure of same-sex attraction and the differences between maternal and paternal responses, as reported by their homosexual daughters and sons. Participants' perceptions of their parents' reactions (evaluated through the Perceived Parental Reactions Scale, PPRS), age at coming out, gender, parental political orientation, and religiosity involvement, the family functioning (assessed through the Family Adaptability and Cohesion Evaluation Scales, FACES IV), were assessed in 164 Italian gay and lesbian young adults. Pearson correlation coefficients were calculated to assess the relation between family functioning and parental reaction to CO. The paired sample t-test was used to compare mothers and fathers' scores on the PPRS. Hierarchical multiple regression was conducted to analyze the relevance of each variable. No differences were found between mothers and fathers in their reaction to the disclosure. The analysis showed that a negative reaction to coming out was predicted by parents' right-wing political conservatism, strong religious beliefs, and higher scores in the scales Rigid and Enmeshed. Findings confirm that a negative parental reaction is the result of poor family resources to face a stressful situation and a strong belief in traditional values. These results have important implications in both clinical and social fields

    Cell Cycle-Dependent Microtubule-Based Dynamic Transport of Cytoplasmic Dynein in Mammalian Cells

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    BACKGROUND:Cytoplasmic dynein complex is a large multi-subunit microtubule (MT)-associated molecular motor involved in various cellular functions including organelle positioning, vesicle transport and cell division. However, regulatory mechanism of the cell-cycle dependent distribution of dynein has not fully been understood. METHODOLOGY/PRINCIPAL FINDINGS:Here we report live-cell imaging of cytoplasmic dynein in HeLa cells, by expressing multifunctional green fluorescent protein (mfGFP)-tagged 74-kDa intermediate chain (IC74). IC74-mfGFP was successfully incorporated into functional dynein complex. In interphase, dynein moved bi-directionally along with MTs, which might carry cargos such as transport vesicles. A substantial fraction of dynein moved toward cell periphery together with EB1, a member of MT plus end-tracking proteins (+TIPs), suggesting +TIPs-mediated transport of dynein. In late-interphase and prophase, dynein was localized at the centrosomes and the radial MT array. In prometaphase and metaphase, dynein was localized at spindle MTs where it frequently moved from spindle poles toward chromosomes or cell cortex. +TIPs may be involved in the transport of spindle dyneins. Possible kinetochore and cortical dyneins were also observed. CONCLUSIONS AND SIGNIFICANCE:These findings suggest that cytoplasmic dynein is transported to the site of action in preparation for the following cellular events, primarily by the MT-based transport. The MT-based transport may have greater advantage than simple diffusion of soluble dynein in rapid and efficient transport of the limited concentration of the protein

    The association of levels of physical activity with metabolic syndrome in rural Australian adults

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    Background:&nbsp; Physical activity (PA) reduces risk factors related to metabolic syndrome. Rurality influences the way people incorporate physical activity into daily life. The aim of this study is to determine the association of PA level with metabolic syndrome in a rural Australian population. The influence of adiposity on these associations is also investigated.Methods: Three cross-sectional population health surveys were conducted in south-east Australia during 2004&ndash;2006 using a random population sample (n = 1563, participation rate 49%) aged 25&ndash;74 years. PA was assessed via a self-administered questionnaire, and components of the metabolic syndrome via anthropometric measurements taken by specially trained nurses and laboratory tests.Results: Approximately one-fifth of participants were inactive in leisure-time and over one-third had metabolic syndrome (men 39%, women 33%; p = 0.022). There was an inverse association between level of PA and metabolic syndrome (p &lt; 0.001). Men who were inactive in leisure-time were more than twice as likely and women more than three times as likely to have metabolic syndrome compared with those having high PA. Body mass index (BMI) is a mediating factor in the association between level of PA and metabolic syndrome.Conclusion: Some PA is better than none if adults, particularly women, are to reduce their risk of metabolic syndrome and associated vascular diseases. Specialised interventions that take rurality into consideration are recommended for adults who are inactive.<br /

    Narrow-line Seyfert 1 galaxies: an amasing class of AGN

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    [Abridged] Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that have all the properties of type 1 Seyfert galaxies but show peculiar characteristics, including the narrowest Balmer lines, strongest Fe II emission, and extreme properties in the X-rays. Line and continuum radio observations provide an optimal tool to access the (often) optically obscured innermost regions of AGN and reveal the kinematics of the gas around their central engines. We investigate the interplay between the peculiar NLS1 class of AGN and the maser phenomenon, to help us understand the nature of the maser emission in some NLS1s where water maser emission has been detected. We observed a sample of NLS1 galaxies with the Green Bank Telescope in a search for water maser emission at 22 GHz. We also reduced and analysed archival Green Bank Telescope and Very Large Array data and produced 22-GHz spectra for the five NLS1 galaxies with detected maser emission. In particular, we imaged the maser and nuclear radio continuum of NGC5506 at subarcsec scales with the Very Large Array. We discovered maser emission in two NLS1 galaxies: IGRJ16385-2057, and IRAS03450+0055. In addition to the three previously known maser detections in the NLS1s Mrk766, NGC4051, and NGC5506, this yields a water maser detection rate in NLS1 galaxies of ~7% (5/71). This value rises significantly to ~21% (5/24) when considering only NLS1 galaxies at recessional velocities less than 10000 km/s. For NGC4051 and NGC5506, we find that the water maser emission is located within 5 and 12 pc, respectively, of nuclear radio continuum knots, which are interpreted as core-jet structures.Comment: 11 pages, 5 figures, 2 tables. Accepted by Astronomy & Astrophysic
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