Diferenciación cromosómica en tres especies de Leptostemonum (Solanum, Solanaceae) endémicos de islas oceánicas.

The chromosomes of Solanum nelsonii, S. sandwicense (endemic to the Hawaii islands) and S. vespertilio (from the Canary islands) were studied by means of classical staining, CMA/DAPI banding and FISH with probes for the 18-5.8-26S and 5S rDNA genes. The aim of this study was to test for chromosomal changes (chromosome number, karyotype, heterochromatin pattern, rDNA loci) during the evolution of these taxa with respect to their continental relatives. An apparent chromosome stasis was confirmed in all three species, in regards to chromosome number and karyotype morphology. However, there was also evidence of cryptic, cumulative sequence changes. Speciation in these species is not likelyassociated with large, obvious chromosome rearrangements or polyploidy, but more likely due to genetic divergence.Diferenciación cromosómica en tres especies de Leptostemonum (Solanum, Solanaceae) endémicos de islas oceánicas. Los cromosomas de Solanum nelsonii, S. sandwicense (endémicosde las islas Hawaii) y de S. vespertilio (de las islas Canarias) fueron estudiados por medio de tinción clásica, bandeo CMA/DAPI y FISH con sondas para los genes de ADNr de 18-5.8-26S y 5S. El objetivofue comprobar cambios cromosómicos (número cromosómico, cariotipo, patrones de heterocromatina y loci de ADNr) durante la evolución de estos taxones, en comparación con sus parientes continentales. Una aparente estasis cromosómica fue confirmada para las tres especies, en lo que respecta a número cromosómico y cariotipos. Sin embargo, también se encontró evidencia de cambios de secuencias crípticos, acumulativos. La especiación en estas especies no estaría asociada a grandes rearreglos cromosómicos o poliploidía, sino más bien a divergencia genética

Novedades Para La Flora De La Argentina

Novelties for the Flora of Argentina. On the occasion of preparing the Flora of Cordoba, new records for the Argentinean flora have been registered as a result of intensive field trips and the revision of the main herbaria collections of the country. In this paper, three new records for the native flora and 17 for the introduced flora (casual aliens and naturalized species) of Argentina are presented. Descriptions, illustrations and a lectotypification are done. Furthermore, the presence of 10 introduced species is formally documented for the first time.Novelties for the Flora of Argentina. On the occasion of preparing the Flora of Cordoba, new records for the Argentinean flora have been registered as a result of intensive field trips and the revision of the main herbaria collections of the country. In this paper, three new records for the native flora and 17 for the introduced flora (casual aliens and naturalized species) of Argentina are presented. Descriptions, illustrations and a lectotypification are done. Furthermore, the presence of 10 introduced species is formally documented for the first time

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Placentation patterns and seed number in fruits of South American Solanum subgen. Leptostemonum (Solanaceae) species

Se analizaron 37 especies sudamericanas pertenecientes a siete secciones de Solanum subgen. Leptostemonum. Fueron consideradas tanto especies andromonoicas como hermafroditas. Se midió el ancho y el largo de sus frutos y se contó el número de semillas por fruto. Se estudiaron bajo lupa y se ilustraron cortes por la zona media de frutos frescos maduros. Se describieron seis patrones de placentación y tres tipos de semillas. Mediante análisis estadístico, se detectó una relación entre el número de semillas, el tamaño del fruto, el color del fruto y el sistema sexual. Estos resultados sugieren que la andromonoecia afecta al tamaño del fruto y su patrón de placentación, para contener un mayor número de semillas

Fruit anatomy of species of Solanum sect. Torva (Solanaceae) Anatomía del fruto en especies de Solanum sect. Torva (Solanaceae)

The mature fruits of 10 South American species of Solanum sect. Torva were studied. Cross and longitudinal microtome sections, stained with astra blue/basic fuchsin, were made for microscopic examination. All species present an epidermis formed by a unistrate layer of small, isodiametric cells, with dense content and cellulosic walls. Immediately below, a hypodermis is always found, consisting of a well-defined layer of lignified cells with a single calcium oxalate crystal occupying the whole lumen of each cell. This is followed by one layer of cellulosic, isodiametric cells with dense cytoplasm and then several collenchymatous layers, sometimes with sclerified cell walls. The mesocarp comprises two zones histologically differentiated: an external one (formed by regular, vacuolated, medium-sized cells with small intercellular spaces), and an internal one, commonly juicy, and developing proliferations among the seeds. The fruits analyzed are alike, and despite some particularities, they can be classified as berries in the conventional sense. All the traits examined agree with the ornithochorous dispersal syndrome. The homogeneity in fruit traits may be due to shared habit, habitat and sexual system.Se estudiaron los frutos maduros de 10 especies sudamericanas de Solanum sect. Torva. Se examinaron en microscopio cortes microtómicos transversales y longitudinales teñidos con azul astral/fucsina básica. Todas las especies presentaron una epidermis unistrata de células pequeñas, isodiamétricas, de contenido denso y paredes celulósicas. Inmediatamente por debajo se encontró siempre una hipodermis, formada por una capa bien definida de células lignificadas con un cristal de oxalato de calcio en el lúmen de cada célula. A continuación se halló otra capa de celulas isodiamétricas, celulósicas, de contenido denso, y luego varias capas de colénquima, en ocasiones con paredes esclerificadas. El mesocarpo presentó dos zonas histologicamente diferenciadas: una externa (formada por células regulares, vacuoladas, de tamaño medio y espacios intercelulares pequeños) y una interna, comúnmente jugosa y que prolifera entre las semillas. No obstante algunas particularidades, los frutos analizados son similares entre sí, y se clasificaron como bayas en sentido convencional. Todos los rasgos analizados concuerdan con el síndrome de dispersión ornitócoro. La homogeneidad en los caracteres puede deberse al hábito, hábitat y sistema sexual compartidos