Constraining the Distribution of L- & T-Dwarfs in the Galaxy

We estimate the thin disk scale height of the Galactic population of L- & T-dwarfs based on star counts from 15 deep parallel fields from the Hubble Space Telescope. From these observations, we have identified 28 candidate L- & T- dwarfs based on their (i'-z') color and morphology. By comparing these star counts to a simple Galactic model, we estimate the scale height to be 350+-50 pc that is consistent with the increase in vertical scale with decreasing stellar mass and is independent of reddening, color-magnitude limits, and other Galactic parameters. With this refined measure, we predict that less than 10^9 M_{sol} of the Milky Way can be in the form L- & T- dwarfs, and confirm that high-latitude, z~6 galaxy surveys which use the i'-band dropout technique are 97-100% free of L- & T- dwarf interlopers.Comment: 4 pages, 4 figures, accepted to ApJ

Neutral Hydrogen and Optical Observations of Edge-on Galaxies: Hunting for Warps

We present 21-cm HI line and optical R-band observations for a sample of 26 edge-on galaxies. The HI observations were obtained with the Westerbork Synthesis Radio Telescope, and are part of the WHISP database (Westerbork HI Survey of Spiral and Irregular Galaxies). We present HI maps, optical images, and radial HI density profiles. We have also derived the rotation curves and studied the warping and lopsidedness of the HI disks. 20 out of the 26 galaxies of our sample are warped, confirming that warping of the HI disks is a very common phenomenon in disk galaxies. Indeed, we find that all galaxies that have an extended HI disk with respect to the optical are warped. The warping usually starts around the edge of the optical disk. The degree of warping varies considerably from galaxy to galaxy. Furthermore, many warps are asymmetric, as they show up in only one side of the disk or exhibit large differences in amplitude in the approaching and receding sides of the galaxy. These asymmetries are more pronounced in rich environments, which may indicate that tidal interactions are a source of warp asymmetry. A rich environment tends to produce larger warps as well. The presence of lopsidedness seems to be related to the presence of nearby companions.Comment: To appear in Astronomy & Astrophysic

Efectos del entrenamiento interválico de alta intensidad durante el periodo transitorio en jugadores de fútbol sub-19

Actualmente existe un creciente interés por la aplicación del entrenamiento interválico de alta intensidad (HIIT) en fútbol (Buchheit et al. 2013). La eficacia mostrada por esta metodología de entrenamiento para mejorar las variables del rendimiento ha provocado una mayor aplicación en deportes colectivos (Iaia et al. 2009). Sin embargo, es escasa la literatura científica acerca de su impacto en fútbol. Por ello, el objetivo del trabajo es comparar los efectos sobre el rendimiento del HIIT versus entrenamiento tradicional durante el periodo transitorio invernal en jugadores de fútbol sub-19

The Milky Way: An Exceptionally Quiet Galaxy; Implications for the formation of spiral galaxies

[Abridged]We compare both the Milky Way and M31 galaxies to local external disk galaxies within the same mass range, using their relative locations in the planes formed by V_flat versus M_K, j_disk, and the average Fe abundance of stars in the galaxy outskirts. We find, for all relationships, that the MW is systematically offset by ~ 1 sigma, showing a significant deficiency in stellar mass, in angular momentum, in disk radius and [Fe/H] in the stars in its outskirts at a given V_flat. On the basis of their location in the M_K, V_flat, and R_d volume, the fraction of spirals like the MW is 7+/-1%, while M31 appears to be a "typical'' spiral. Our Galaxy appears to have escaped any significant merger over the last ~10 Gyrs which may explain why it is deficient by a factor 2 to 3 in stellar mass, angular momentum and outskirts metallicity and then, unrepresentative of the typical spiral. As with M31, most local spirals show evidence for a history shaped mainly by relatively recent merging. We conclude that the standard scenario of secular evolution is generally unable to reproduce the properties of most (if not all) spiral galaxies. However, the so-called "spiral rebuilding'' scenario proposed by Hammer et al. 2005 is consistent with the properties of both distant galaxies and of their descendants - the local spirals.Comment: 14 pages, 6 figures, to appear in Ap

Le séquençage du génome de deux trypanosomatides de plantes - Phytomonas spp.- au secours d'une taxonomie dépassée

Plusieurs espèces de plantes laticifères sont parasitées au niveau des tubes laticifères, par des Trypanosomatidae. La question de leur pouvoir pathogène reste ouverte. Un nom de genre leur a été attribué arbitrairement: " Phytomonas", uniquement basée sur la nature de l'hôte. Or il a été montré que ces organismes se multipliaient dans les insectes qui les transmettaient. De plus, depuis les années 80, on sait que d'autres trypanosomatidés, jusque là considérés comme des " trypanosomatidés monoxéniques d'insectes "" (Crithidia, Herpetomonas, Leptomonas) peuvent être transmis par hétéroptères à des fruits de diverses familles, dont les solanacées (tomate). En Amérique latine et dans la Caraïbe, il existe des trypanosomatidés intraphlo èmiques spécifiquement associées à des dépérissements de palmiers (cocotier, palmier à huile, Arecaceae), de cultures horticoles (Alpinia purpurata, Zingiberaceae) et du caféier (Rubiaceae). Le genre arbitraire Phytomonas ne reflète donc pas la diversité des trypanosomatidés se multipliant dans des milieux aussi différents que le latex, la sève, la pulpe des fruits ou des graines, sur différents continents, et ne fait pas de différence entre les organismes pathogènes responsables de maladies aux graves conséquences économiques et ceux qui s'apparentent èa des symbiontes. Nous avons travaillée à la caractérisation de ces trypanosomatidés en utilisant divers marqueurs moléculaires comme le gène du Splice Leader RNA, l'ARN r 5S, les mini cercles d'ADN kinetoplastique et les ITS de l'opéron ribosomal. En tenant compte de ces résultats, en les associant aux données sérologiques et des iso enzymes et RAPD, nous pouvons conclure à l'existence de 10 "groupes" différents. Parmi ces groupes certains se démarquent très nettement. C'est le cas des trypanosomatidés intraphlo èmiques (" groupe H ""). Par leur localisation (tubes criblées du phloème), leur effet pathogène, leur endémisme en Amérique latine, leur culture in vitro, qui contrairement aux autres ne peut se réaliser qu'avec des cellules nourricières d'insectes, et les marqueurs moléculaires, ils sont uniques. Un autre groupe se distingue : " D "", comprenant des isolats du latex de l'Ancien Monde (Inde, Sénégal et France). L'étude des caryotypes moléculaires d'un isolat de chacun de ces deux groupes (EM1 d'Euphorbia pinea de France et Hart1 associée au dépérissement du cocotier en Guyane) révèle bien deux organismes différents avec respectivement 21 chromosomes et 7 chromosomes hétérologues. L'ensemble de ces résultats ainsi que d'autres données conduisent à dire qu'il serait nécessaire de réviser la taxonomie des trypanosomatidés de plantes/insectes. Pour étayer cette présomption, le génome de deux isolats, un isolat du latex (EM1) et un du phloème (Hart1), a été séquencé au Génoscope. Les premiers résultats montrant les différences entre ces deux groupes de trypanosomatidés seront présentées. Ils permettront de fournir des clés pour établir une nouvelle taxonomie, mais aussi d'identifier de possibles nouvelles méthodes de lutte. Projet ANR -08- GENM-020-001 SEQTRYPLANT. (Résumé d'auteur

Near-infrared and optical observations of galactic warps: A common, unexplained feature of most discs

Context: Warps occurring in galactic discs have been studied extensively in HI and in the optical, but rarely in the near-infrared (NIR) bands that trace the older stellar populations. Aims: We provide NIR data of nearby edge-on galaxies, combined with optical observations, for direct comparison of the properties of galactic warps as a function of wavelength, and calculate warp curves for each galaxy and obtain the characteristic warp parameters. We discuss these properties as possible constraints to the different mechanisms that have been proposed for the development and persistence of galactic warps. Methods: We observed 20 galaxies that were selected from a statistically complete diameter-limited subsample of edge-on disc galaxies. We used the Cerro Tololo Infrared Imager (CIRIM) at the CTIO 1.5m Ritchey-Chretien telescope to acquire the NIR data. We used the 1.54m Danish and 0.92m Dutch telescopes at the European Southern Observatory's La Silla site for our optical observations. Results: Our results show that 13 of our 20 sample galaxies are warped, with the warp more pronounced in the optical than at NIR wavelengths. In the remaining seven galaxies, no warp is apparent within the limitations of our automated detection method. The transition between the unperturbed inner disc and the outer, warped region is rather abrupt. S0 galaxies exhibit very small or no warps. The magnetic model remains one of a number of interesting formation scenarios.Comment: 16 page

The Biostimulant, Potassium Humate Ameliorates Abiotic Stress in Arabidopsis thaliana by Increasing Starch Availability

[EN] Potassium humate is a widely used biostimulant known for its ability to enhance growth and improve tolerance to abiotic stress. However, the molecular mechanisms explaining its effects remain poorly understood. In this study, we investigated the mechanism of action of potassium humate using the model plant Arabidopsis thaliana. We demonstrated that a formulation of potassium humate effectively increased the fresh weight accumulation of Arabidopsis plants under normal conditions, salt stress (sodium or lithium chloride), and particularly under osmotic stress (mannitol). Interestingly, plants treated with potassium humate exhibited a reduced antioxidant response and lower proline accumulation, while maintaining photosynthetic activity under stress conditions. The observed sodium and osmotic tolerance induced by humate was not accompanied by increased potassium accumulation. Additionally, metabolomic analysis revealed that potassium humate increased maltose levels under control conditions but decreased levels of fructose. However, under stress, both maltose and glucose levels decreased, suggesting changes in starch utilization and an increase in glycolysis. Starch concentration measurements in leaves showed that plants treated with potassium humate accumulated less starch under control conditions, while under stress, they accumulated starch to levels similar to or higher than control plants. Taken together, our findings suggest that the molecular mechanism underlying the abiotic stress tolerance conferred by potassium humate involves its ability to alter starch content under normal growth conditions and under salt or osmotic stress.This research was funded by the CDTI program project EXP 00137666/IDI-20210456. awarded to CALDIC Ibérica S.L. and the research contract. "DESARROLLO DE FORMULADOS BIOESTIMULANTES Y BIOFERTILIZANTES INNOVADORES DE ORIGEN NATURAL (CALBIO) DESTINADOS A LA AGRICULTURA CONVENCIONAL Y ECOLÓGICA. ESTUDIO CIENTÍFICO DE EFECTOS SINÉRGICOS ENTRE BIOACTIVOS MICROBIANOS Y NO MICROBIANOS" Between CALDIC Ibérica S.L. and Universitat Politècnica de València. The APC was funded by the aforementioned research contract.Benito, P.; Bellón, J.; Porcel, R.; Yenush, L.; Mulet, JM. (2023). The Biostimulant, Potassium Humate Ameliorates Abiotic Stress in Arabidopsis thaliana by Increasing Starch Availability. International Journal of Molecular Sciences. 24(15):1-21. https://doi.org/10.3390/ijms241512140121241