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Effects of radial flows on the chemical evolution of the Milky Way disk

The majority of chemical evolution models assume that the Galactic disk forms by means of infall of gas and divide the disk into several independent rings without exchange of matter between them. However, if gas infall is important, radial gas flows should be taken into account as a dynamical consequence of infall. The aim of this paper is to test the effect of radial gas flows on detailed chemical evolution models (one-infall and two-infall) for the Milky Way disk with different prescriptions for the infall law and star formation rate. We found, that with a gas radial inflow of constant speed the metallicity gradient tends to steepen. Taking into account a constant time scale for the infall rate along the Galaxy disk and radial flows with a constant speed, we obtained a too flat gradient, at variance with data, implying that an inside-out formation and/or a variable gas flow speed are required. To reproduce the observed gradients the gas flow should increase in modulus with the galactocentric distance, both in the one-infall and two-infall models. However, the inside-out disk formation coupled with a threshold in the gas density (only in the two-infall model) for star formation and/or a variable efficiency of star formation with galactocentric distance can also reproduce the observed gradients without radial flows. We showed that the radial flows can be the most important process in reproducing abundance gradients but only with a variable gas speed. Finally, one should consider that uncertainties in the data concerning gradients prevent us to draw firm conclusions. Future more detailed data will help to ascertain whether the radial flows are a necessary ingredient in the formation and evolution of the Galactic disk and disks in general.Comment: Accepted by A&A; 11 pages, 16 figure

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Le glyoxal (un possible substitut du formaldéhyde en anatomie pathologique)

Le formol, utilisé dilué au 1/10ème ou sous forme de fixateurs composés de formules variées, représente à l'heure actuelle l'agent fixant le plus employé en pathologie. C'est à partir de prélèvements fixés par des liquides à base de formaldéhyde qu'ont été établies les sémiologies macroscopiques et microscopiques d'une majorité de maladies et définis le plus grand nombre des paramètres pronostiques et prédictifs de la réponse thérapeutique. Le formol n'est, cependant, pas un fixateur idéal. Il présente notamment des risques pour la santé et a récemment été classé par le Centre International de Recherche sur le Cancer (CIRC) comme cancérogène pour l'homme. La réglementation impose sa substitution si la mesure est techniquement possible. Ceci a conduit de nombreux fabricants à commercialiser des substituts qui, tout en étant inoffensifs , présenteraient les quallités attendues d'un fixateur polyvalent pour l'histologie. Il s'agit, le plus souvent, de fixateurs composés à base de glyoxal. Dans notre travail, les propriétés fixatrices de plusieurs solutions de glyoxal ont été comparées à celles correspondantes du formol. Sur la plupart des points étudiés (respect de la microanatomie et de l'antigénicité, conservation des acides nucïéiques, aptitude à conserver les pièces opératoires, biocidie, etc), les solutions de glyoxal se sont révélées très inférieures au formol. Elles ne peuvent donc être recommandées comme fixateur polyvalent.NANCY1-SCD Medecine (545472101) / SudocNANCY1-Bib. numérique (543959902) / SudocSudocFranceF

Analyse du comportement mécanique d'un os à partir d'images scanner

Ce travail propose une méthode pour l'analyse du comportement mécanique d'un os ostéoporotique basée sur l'imagerie scanner. Dans un premier temps, les propriétés mécaniques de l'os cortical et de l'os trabéculaire d'une tête de radius sont identifiées pour des échantillons numériques tridimensionnels construits à partir d'images scanner. Pour chaque pixel, la valeur locale du module d'Young est reliée à l'indice de gris. La simulation d'essais de compression et de cisaillement permet d'identifier un comportement isotrope pour l'os cortical et un comportement orthotrope pour l'os trabéculaire. Dans un second temps, les différentes images scanner sont utilisées pour construire un modèle numérique 3D de la tête du radius. Une analyse par éléments finis du modèle élaboré, basée sur les propriétés mécaniques identifiées précédemment, permet d'examiner le comportement global et local de la tête du radius sous différentes hypothèses de sollicitation

Anatomic characterization of cavotricuspid isthmus by 3D transesophageal echocardiography in patients undergoing radiofrequency ablation of typical atrial flutter

Aims Radiofrequency ablation (RFA) is the treatment of choice of cavotricuspid isthmus (CTI)-dependent atrial flutter. Procedural time is highly variable due to anatomical structures. This study aimed to characterize CTI anatomy by transesophageal 3D echocardiography imaging (3D-TEE) to identify anatomic structures related to longer ablation time. Methods and results Thirty-one consecutive patients (mean age 67.3 ± 11.5 years, 22 males) underwent CTI-ablation procedure. Before ablation, TEE was performed and 3D-TEE images were acquired to evaluate CTI anatomy qualitatively as well as perform measures of CTI morphological features. The electrophysiologist performing RFA was blinded to 3D-TEE data. Bidirectional block of CTI was achieved in all patients without procedural complications after a median ablation time of 11 (IQR 7-14) min. Patients with RFA time ≥11 min (Group 2) presented lower left ventricular ejection fraction (51.1 ± 17.0 vs. 59.5 ± 6.6%, P < 0.010), a larger left atrium (46.2 ± 8.4 vs. 39.9 ± 9.4 mm, P < 0.058), and, more frequently, a right atrial pouch (12/16 patients vs. 4/15, P = 0.012) compared with patients with RFA time < 11 min (Group 1); CTI pouch was significantly deeper in Group 2 compared with Group 1: telediastolic (TD) pouch depth was 10.4 ± 4.5 vs. 6.3 ± 1.5 mm (P = 0.003) and telesystolic (TS) depth 12.8 ± 4.4 vs. 7.0 ± 1.4 mm (P < 0.001), respectively. TD isthmus length, prominent pectinate muscle, and presence of an Eustachian ridge (ER) did not differ between the two groups. Conclusion Routine pre-procedural 3D-TEE imaging is extremely helpful in qualitative and quantitative evaluation of CTI anatomy in patients undergoing RFA for symptomatic typical atrial flutter. Detection of a deep right atrial pouch was found to be associated with significantly prolonged CTI ablation time to achieve bidirectional block

Integrating functional diversity into tropical forest plantation designs to study ecosystem processes

• The elucidation of relationships between biodiversity and ecosystem processes has been limited by the definition of metrics of biodiversity and their integration into experimental design. Functional trait screening can strengthen the performance of these designs. • We suggest the use of Rao’s quadratic entropy to measure both functional diversity and phylogenetic diversity of species mixtures proposed for an experimental design, and demonstrate how they can provide complementary information. • We also present an index assessing the statistical performance of these independent variables in different experimental designs. Measurement of independent variables as continuous vs. discrete variables reduces statistical performance, but improves the model by quantifying species differences masked by group assignments. • To illustrate these advances, we present an example from a tropical forest tree community in which we screened 38 species for nine functional traits. The proposed TropiDEP design is based on the relative orthogonality of two multivariate trait axes defined using principal component analysis. • We propose that independent variables describing functional diversity might be grouped to calculate independent variables describing suites of different traits with potentially different effects on particular ecosystem processes. In other systems these axes may differ from those reported here, yet the methods of analysis integrating functional and phylogenetic diversity into experimental design could be universal