318 research outputs found
Review of the life history and conservation of federally endangered plant species of the Lower Rio Grande Valley, Texas, USA
This review aims to summarize information critical to the conservation of the federally listed endangered species of South Texas, which occur along the border of Texas and Mexico. This paper describes the characteristics, habitat, population status, distribution, life history, threats, and restoration of endangered plant species of the Lower Rio Grande Valley, Texas, which includes Cameron, Willacy, Hidalgo, and Starr County. Seven federally listed species are considered including Ambrosia cheiranthifolia, Asclepias prostrata, Astrophytum asterias, Ayenia limitaris, Manihot walkerae, Lesquerella thamnophila (syn. Physaria thamnophila), and Thymophylla tephroleuca. An eighth species, Physostegia correllii is under consideration for federal listing by the U.S. Fish and Wildlife Service. This paper assembles information on the background, biological status, major threats, and conservation to aid managers and the scientific community in restoring and managing these species.
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El objetivo de esta revisión es resumir la información crítica para la conservación de las especies en peligro de extinción incluidas en la lista federal del sur de Texas, que se encuentran a lo largo de la frontera entre Texas y México. En este documento se describen las características, el hábitat, el estado de la población, la distribución, el ciclo biológico, las amenazas y la restauración de las especies vegetales en peligro de extinción del Valle Inferior del Río Grande, Texas, que incluye los condados de Cameron, Willacy, Hidalgo y Starr. Se consideran siete especies incluidas en la lista federal, entre ellas Ambrosia cheiranthifolia, Asclepias prostrata, Astrophytum asterias, Ayenia limitaris, Manihot walkerae, Lesquerella thamnophila (syn. Physaria thamnophila) y Thymophylla tephroleuca. Una octava especie, Physostegia correllii, está siendo considerada por el Servicio de Pesca y Vida Silvestre de EE.UU. para su inclusión en la lista federal. Este documento reúne información sobre los antecedentes, el estado biológico, las principales amenazas y la conservación para ayudar a los gestores y a la comunidad científica a restaurar y gestionar estas especies
Percutaneous treatment with Mitraclip for functional mitral regurgitation: medium-term follow up according to left ventricular function
Background: Functional mitral regurgitation (FMR) is a bad prognosis condition despite optimal medical treatment. Nowadays there is an open debate about the surgical versus percutaneous treatment. The main objective of this study is to evaluate the mid-term follow up clinical outcomes of patients with FMR treated with MitraClip((R)) system, according to their left ventricular ejection fraction (LVEF). Methods: Data was obtained from two experienced centers in transcatheter mitral valve repair (TMVR). All consecutive cases of severe FMR undergoing TMVR in both centers with the same inclusion criteria were included prospectively in this study and followed-up. Periodical follow-ups with clinical and echocardiographic evaluation were scheduled from the baseline procedure, at 3 months and then yearly. Results: From October 2015 to October 2019, a total of 119 patients with FMR at 2 centers in Spain underwent TMVR with the MitraClip((R)) procedure and were included in this study. The mean age was 73.8+/-8.9 years old and 32 patients (26.9%) were female. A 39.5% of cases [47] had a LVEF 30% (group 2). There was a similar distribution in cardiovascular risk factors, age and other diseases. All MitraClip((R)) implantations were elective and procedural success was achieved in 110 patients (92.4%) with a similar distribution between the groups. There were no differences in procedural time and the number of implanted clips. The median follow-up was 22.6 months (IQR, 11.43-34.98 months). The primary combined endpoint occurred in the 41.6% of the global cohort, 57.5% in group 1 and 30.99% in group 2 (P=0.036). LVEF was associated to the main event in the multivariate analysis (HR 2.09, 95% CI: 1.12-3.89; P=0.02). Conclusions: The MitraClip edge-to-edge technique is a safe and effective procedure for the treatment of FMR. In this study, patients with LVEF >30% treated with Mitraclip presented better clinical cardiovascular outcomes than those with a LVEF </=30%. Regardless clinical outcomes, at the end of the follow-up, there was a sustained reduction in MR grades and an important improvement in NYHA functional class
Binocular Encoding in the Damselfly Pre-motor Target Tracking System.
Akin to all damselflies, Calopteryx (family Calopterygidae), commonly known as jewel wings or demoiselles, possess dichoptic (separated) eyes with overlapping visual fields of view. In contrast, many dragonfly species possess holoptic (dorsally fused) eyes with limited binocular overlap. We have here compared the neuronal correlates of target tracking between damselfly and dragonfly sister lineages and linked these changes in visual overlap to pre-motor neural adaptations. Although dragonflies attack prey dorsally, we show that demoiselles attack prey frontally. We identify demoiselle target-selective descending neurons (TSDNs) with matching frontal visual receptive fields, anatomically and functionally homologous to the dorsally positioned dragonfly TSDNs. By manipulating visual input using eyepatches and prisms, we show that moving target information at the pre-motor level depends on binocular summation in demoiselles. Consequently, demoiselles encode directional information in a binocularly fused frame of reference such that information of a target moving toward the midline in the left eye is fused with information of the target moving away from the midline in the right eye. This contrasts with dragonfly TSDNs, where receptive fields possess a sharp midline boundary, confining responses to a single visual hemifield in a sagittal frame of reference (i.e., relative to the midline). Our results indicate that, although TSDNs are conserved across Odonata, their neural inputs, and thus the upstream organization of the target tracking system, differ significantly and match divergence in eye design and predatory strategies. VIDEO ABSTRACT
Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip
Background: Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods: We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results: Ninety-three patients (68.2+/-10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0+/-17.8 vs. 2.7+/-13.5, P=0.002), sustained VT or ventricular fibrillation (0.9+/-2.5 vs. 0.5+/-2.9, P=0.012) and ICD antitachycardia therapies (2.5+/-12.0 vs. 0.9+/-5.0, P=0.033) were observed. Conclusions: PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort
Stellar Population gradients in galaxy discs from the CALIFA survey
While studies of gas-phase metallicity gradients in disc galaxies are common,
very little has been done in the acquisition of stellar abundance gradients in
the same regions. We present here a comparative study of the stellar
metallicity and age distributions in a sample of 62 nearly face-on, spiral
galaxies with and without bars, using data from the CALIFA survey. We measure
the slopes of the gradients and study their relation with other properties of
the galaxies. We find that the mean stellar age and metallicity gradients in
the disc are shallow and negative. Furthermore, when normalized to the
effective radius of the disc, the slope of the stellar population gradients
does not correlate with the mass or with the morphological type of the
galaxies. Contrary to this, the values of both age and metallicity at 2.5
scale-lengths correlate with the central velocity dispersion in a similar
manner to the central values of the bulges, although bulges show, on average,
older ages and higher metallicities than the discs. One of the goals of the
present paper is to test the theoretical prediction that non-linear coupling
between the bar and the spiral arms is an efficient mechanism for producing
radial migrations across significant distances within discs. The process of
radial migration should flatten the stellar metallicity gradient with time and,
therefore, we would expect flatter stellar metallicity gradients in barred
galaxies. However, we do not find any difference in the metallicity or age
gradients in galaxies with without bars. We discuss possible scenarios that can
lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&
The Mass-Metallicity relation explored with CALIFA: I. Is there a dependence on the star formation rate?
We present the results on the study of the global and local M-Z relation
based on the first data available from the CALIFA survey (150 galaxies). This
survey provides integral field spectroscopy of the complete optical extent of
each galaxy (up to 2-3 effective radii), with enough resolution to separate
individual HII regions and/or aggregations. Nearly 3000 individual HII
regions have been detected. The spectra cover the wavelength range between
[OII]3727 and [SII]6731, with a sufficient signal-to-noise to derive the oxygen
abundance and star-formation rate associated with each region. In addition, we
have computed the integrated and spatially resolved stellar masses (and surface
densities), based on SDSS photometric data. We explore the relations between
the stellar mass, oxygen abundance and star-formation rate using this dataset.
We derive a tight relation between the integrated stellar mass and the
gas-phase abundance, with a dispersion smaller than the one already reported in
the literature (0.07 dex). Indeed, this
dispersion is only slightly larger than the typical error derived for our
oxygen abundances. However, we do not find any secondary relation with the
star-formation rate, other than the one induced due to the primary relation of
this quantity with the stellar mass. We confirm the result using the 3000
individual HII regions, for the corresponding local relations.
Our results agree with the scenario in which gas recycling in galaxies, both
locally and globally, is much faster than other typical timescales, like that
of gas accretion by inflow and/or metal loss due to outflows. In essence,
late-type/disk dominated galaxies seem to be in a quasi-steady situation, with
a behavior similar to the one expected from an instantaneous
recycling/closed-box model.Comment: 19 Pages, 8 figures, Accepted for Publishing in Astronomy and
Astrophysics (A&A
Identifying human diamine sensors for death related putrescine and cadaverine molecules
Pungent chemical compounds originating from decaying tissue are strong drivers of animal behavior. Two of the best-characterized death smell components are putrescine (PUT) and cadaverine (CAD), foul-smelling molecules produced by decarboxylation of amino acids during decomposition. These volatile polyamines act as 'necromones', triggering avoidance or attractive responses, which are fundamental for the survival of a wide range of species. The few studies that have attempted to identify the cognate receptors for these molecules have suggested the involvement of the seven-helix trace amine-associated receptors (TAARs), localized in the olfactory epithelium. However, very little is known about the precise chemosensory receptors that sense these compounds in the majority of organisms and the molecular basis of their interactions. In this work, we have used computational strategies to characterize the binding between PUT and CAD with the TAAR6 and TAAR8 human receptors. Sequence analysis, homology modeling, docking and molecular dynamics studies suggest a tandem of negatively charged aspartates in the binding pocket of these receptors which are likely to be involved in the recognition of these small biogenic diamines
Uncovering multiple Wolf-Rayet star clusters and the ionized ISM in Mrk 178: the closest metal-poor Wolf-Rayet H ii galaxy
New integral field spectroscopy (IFS) has been obtained for the nearby metal-poor Wolf–Rayet (WR) galaxy Mrk 178 to examine the spatial correlation between its WR stars and the neighbouring ionized interstellar medium (ISM). The strength of the broad WR features and its low metallicity make Mrk 178 an intriguing object. We have detected the blue and red WR bumps in different locations across the field of view (∼300 pc × 230 pc) in Mrk 178. The study of the WR content has been extended, for the first time, beyond its brightest star-forming knot uncovering new WR star clusters. Using Large/Small Magellanic Cloud-template WR stars, we empirically estimate a minimum of ∼20 WR stars within the region sampled. Maps of the spatial distribution of the emission lines and of the physical–chemical properties of the ionized ISM have been created and analysed. Here, we refine the statistical methodology by Pérez-Montero et al. (2011) to probe the presence of variations in the ISM properties. An error-weighted mean of 12+log(O/H) = 7.72 ± 0.01 is taken as the representative oxygen abundance for Mrk 178. A localized N and He enrichment, spatially correlated with WR stars, is suggested by this analysis. Nebular He II λ4686 emission is shown to be spatially extended reaching well beyond the location of the WR stars. This spatial offset between WRs and He II emission can be explained based on the mechanical energy input into the ISM by the WR star winds, and does not rule out WR stars as the He II ionization source. We study systematic aperture effects on the detection and measurement of the WR features, using Sloan Digital Sky Survey spectra combined with the power of IFS. In this regard, the importance of targeting low metallicity nearby systems is discussed
Morpho-kinematic properties of field S0 bulges in the CALIFA survey
We study a sample of 28 S0 galaxies extracted from the integral-field
spectroscopic (IFS) survey CALIFA. We combine an accurate two-dimensional (2D)
multi-component photometric decomposition with the IFS kinematic properties of
their bulges to understand their formation scenario. Our final sample is
representative of S0s with high stellar masses ().
They lay mainly on the red sequence and live in relatively isolated
environments similar to that of the field and loose groups. We use our 2D
photometric decomposition to define the size and photometric properties of the
bulges, as well as their location within the galaxies. We perform mock
spectroscopic simulations mimicking our observed galaxies to quantify the
impact of the underlying disc on our bulge kinematic measurements (
and ). We compare our bulge corrected kinematic measurements with the
results from Schwarzschild dynamical modelling. The good agreement confirms the
robustness of our results and allows us to use bulge reprojected values of
and . We find that the photometric ( and ) and
kinematic ( and ) properties of our field S0 bulges are not
correlated. We demonstrate that this morpho-kinematic decoupling is intrinsic
to the bulges and it is not due to projection effects. We conclude that
photometric diagnostics to separate different types of bulges (disc-like vs
classical) might not be useful for S0 galaxies. The morpho-kinematics
properties of S0 bulges derived in this paper suggest that they are mainly
formed by dissipation processes happening at high redshift, but dedicated
high-resolution simulations are necessary to better identify their origin.Comment: 31 pages, 19 figures. Accepted for publication in MNRA
The histone demethylase LSD1 regulates inner ear progenitor differentiation through interactions with Pax2 and the NuRD repressor complex
The histone demethylase LSD1 plays a pivotal role in cellular differentiation, particularly in silencing lineage-specific genes. However, little is known about how LSD1 regulates neurosensory differentiation in the inner ear. Here we show that LSD1 interacts directly with the transcription factor Pax2 to form the NuRD co-repressor complex at the Pax2 target gene loci in a mouse otic neuronal progenitor cell line (VOT-N33). VOT-N33 cells expressing a Pax2-response element reporter were GFP-negative when untreated, but became GFP positive after forced differentiation or treatment with a potent LSD inhibitor. Pharmacological inhibition of LSD1 activity resulted in the enrichment of mono- and di-methylation of H3K4, upregulation of sensory neuronal genes and an increase in the number of sensory neurons in mouse inner ear organoids. Together, these results identify the LSD1/NuRD complex as a previously unrecognized modulator for Pax2-mediated neuronal differentiation in the inner ear
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