Improving the Ni I atomic model for solar and stellar atmospheric models

Neutral nickel (Ni I) is abundant in the solar atmosphere and is one of the important elements that contribute to the emission and absorption of radiation in the spectral range between 1900 and 3900 A. Previously, the Solar Radiation Physical Modeling (SRPM) models of the solar atmosphere considered only few levels of this species. Here we improve the Ni I atomic model by taking into account 61 levels and 490 spectral lines. We compute the populations of these levels in full NLTE using the SRPM code and compare the resulting emerging spectrum with observations. The present atomic model improves significantly the calculation of the solar spectral irradiance at near-UV wavelengths that are important for Earth atmo spheric studies, and particularly for ozone chemistry.Comment: Accepted for publication in The Astrophysical Journa

Human Poisoning from Marine Toxins: Unknowns for Optimal Consumer Protection

Marine biotoxins are produced by aquatic microorganisms and accumulate in shellfish or finfish following the food web. These toxins usually reach human consumers by ingestion of contaminated seafood, although other exposure routes like inhalation or contact have also been reported and may cause serious illness. This review shows the current data regarding the symptoms of acute intoxication for several toxin classes, including paralytic toxins, amnesic toxins, ciguatoxins, brevetoxins, tetrodotoxins, diarrheic toxins, azaspiracids and palytoxins. The information available about chronic toxicity and relative potency of different analogs within a toxin class are also reported. The gaps of toxicological knowledge that should be studied to improve human health protection are discussed. In general, gathering of epidemiological data in humans, chronic toxicity studies and exploring relative potency by oral administration are critical to minimize human health risks related to these toxin classes in the near future.Support from the following FEDER cofunded-grants. From Conselleria de Cultura, Educacion e Ordenación Universitaria Xunta de Galicia, 2017 GRC GI-1682 (ED431C 2017/01). From CDTI and Technological Funds, supported by Ministerio de Economía, Industria y Competitividad, AGL2014-58210-R, AGL2016-78728-R (AEI/FEDER, UE), ISCIII/PI16/01830 and RTC-2016-5507-2, ITC-20161072. From European Union POCTEP 0161-Nanoeaters -1-E-1, Interreg AlertoxNet EAPA-317-2016, and H2020 778069-EMERTOX

Different toxic effects of YTX in tumor K-562 and lymphoblastoid cell lines

Yessotoxin (YTX) modulates cellular phosphodiesterases (PDEs). In this regard, opposite effects had been described in the tumor model K-562 cell line and fresh human lymphocytes in terms of cell viability, cyclic adenosine 3´,5´-cyclic monophosphate (cAMP) production and protein expression after YTX treatment. Studies in depth of the pathways activated by YTX in K-562 cell line, have demonstrated the activation of two different cell death types, apoptosis and autophagy after 24 and 48 hours of treatment, respectively. Furthermore, the key role of type 4A PDE (PDE4A) in both pathways activated by YTX was demonstrated. Therefore, taking into account the differences between cellular lines and fresh cells, a study of cell death pathways activated by YTX in a non-tumor cell line with mitotic activity, was performed. The cellular model used was the lymphoblastoid cell line that represents a non-tumor model with normal apoptotic and mitotic machinery. In this context, cell viability and cell proliferation, expression of proteins involved in cell death activated by YTX and mitochondrial mass, were studied after the incubation with the toxin. Opposite to the tumor model, no cell death activation was observed in lymphoblastoid cell line in the presence of YTX. In this sense, variations in apoptosis hallmarks were not detected in the lymphoblastoid cell line after YTX incubation, whereas this type I of programmed cell death was observed in K-526 cells. On the other hand, autophagy cell death was triggered in this cellular line, while other autophagic process is suggested in lymphoblastoid cells. These YTX effects are related to PDE4A in both cellular lines. In addition, while cell death is triggered in K-526 cells after YTX treatment, in lymphoblastoid cells the toxin stops cellular proliferation. These results point to YTX as a specific toxic compound of tumor cells, since in the non-tumor lymphoblastoid cell line, no cell death hallmarks are observed

The Ultraviolet Radiation Environment Around M dwarf Exoplanet Host Stars

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both FUV and NUV wavelengths. The combined FUV+NUV spectra are publically available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV quiet" M dwarfs are observed. The bright stellar Ly-alpha emission lines are reconstructed, and we find that the Ly-alpha line fluxes comprise ~37-75% of the total 1150-3100A flux from most M dwarfs; > 10^{3} times the solar value. The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O2 and O3, is shown to be ~0.5-3 for all M dwarfs in our sample, > 10^{3} times the solar ratio. For the four stars with moderate signal-to-noise COS time-resolved spectra, we find UV emission line variability with amplitudes of 50-500% on 10^{2} - 10^{3} s timescales. Finally, we observe relatively bright H2 fluorescent emission from four of the M dwarf exoplanetary systems (GJ 581, GJ 876, GJ 436, and GJ 832). Additional modeling work is needed to differentiate between a stellar photospheric or possible exoplanetary origin for the hot (T(H2) \approx 2000-4000 K) molecular gas observed in these objects.Comment: ApJ, accepted. 16 pages, 10 figures. On-line data at: http://cos.colorado.edu/~kevinf/muscles.htm

Pulsar wind nebulae around the southern pulsars PSR B1643-43 and PSR B1706-44

We present high resolution VLA images taken at the wavelengths of lambda 20 cm, lambda 6 cm, and lambda 3.6 cm in the vicinity of the pulsars PSR B1706-44 (PSR J1709-4428) and PSR B1643-43 (PSR J1646-4346). Both of these pulsars are young (<30,000 yrs) and have large spin-down luminosities (e+35 erg/sec) and hence are good candidates to search for extended synchrotron nebula excited by the relativistic pulsar wind. For PSR B1643-43 we found evidences of a 4'comet-shaped nebula, suggestive of a synchrotron ``wake'' left by a fast moving pulsar. PSR B1706-44 appears surrounded by a spherical nebula approximately 3 ' in diameter. Based on their morphology, the detection of significant linear polarization (>20%), and their flat radio spectra (alpha=0.25-0.3, where S_nu aprox nu^-alpha) we argue that these are wind nebulae powered by the rotational energy loss of the respective pulsars

Modelling chromospheric line profiles as diagnostics of velocity fields in {\omega} Centauri red giant stars

Context. Mass loss of ~0.1-0.3 M$_{\odot}$ from Population II red giant stars (RGB) is a requirement of stellar evolution theory in order to account for several observational evidences in globular clusters. Aims. The aim of this study is to detect the presence of outward velocity fields, which are indicative of mass outflow, in six luminous red giant stars of the stellar cluster {\omega} Cen. Methods. We compare synthetic line profiles computed using relevant model chromospheres to observed profiles of the H{\alpha} and Ca II K lines. The spectra were taken with UVES (R=45,000) and the stars were selected so that three of them belong to the metal-rich population and three to the metal-poor population, and sample as far down as 1 to 2.5 magnitudes fainter than the respective RGB tips. Results. We do indeed reveal the presence of low-velocity outward motions in four of our six targets, without any apparent correlation with astrophysical parameters. Conclusions. This provides direct evidence that outward velocity fields and mass motions exist in RGB stars as much as 2.5 mag fainter than the tip. On the assumption that the mass outflow may eventually lead to mass loss from the star, we estimate mass-loss rates of some 10^{-9}-10^{-10} M$_{\odot}$ yr^{-1} that are compatible with the stellar evolution requirements. These rates seem to be correlated with luminosity rather than metallicity.Comment: Accepted by A&

Improvements in the determination of ISS Ca II K parameters

Measurements of the ionized Ca II K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a ground-based proxy to model the solar ultraviolet flux variation that may influence the Earth's climate. Full disk images of the Sun in Ca II K have been available from various observatories for more than 100 years and latter synoptic Sun-as-a-star observations in Ca II K began in the early 1970s. One of these instruments, the Integrated Sunlight Spectrometer (ISS) has been in operation at Kitt Peak (Arizona) since late 2006. The ISS takes daily observations of solar spectra in nine spectra bands, including the Ca II K and H line s. We describe recent improvements in data reduction of Ca II K observations, and present time variations of nine parameters derived from the profile of this spectral line

Toxic Action Reevaluation of Okadaic Acid, Dinophysistoxin-1 and Dinophysistoxin-2: Toxicity Equivalency Factors Based on the Oral Toxicity Study

Background/Aims: Okadaic acid (OA) and the structurally related compounds dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2) are marine phycotoxins that cause diarrheic shellfish poisoning (DSP) in humans due to ingestion of contaminated shellfish. In order to guarantee consumer protection, the regulatory authorities have defined the maximum level of DSP toxins as 160 µg OA equivalent kg-1 shellfish meat. For risk assessment and overall toxicity determination, knowledge of the relative toxicities of each analogue is required. In absence of enough information from human intoxications, oral toxicity in mice is the most reliable data for establishing Toxicity Equivalence Factors (TEFs). Methods: Toxins were administered to mice by gavage, after that the symptomatology and mice mortality was registered over a period of 24 h. Organ damage data were collected at necropsy and transmission electron microscopy (TEM) was used for ultrastructural studies. Toxins in urine, feces and blood were analyzed by HPLC-MS/MS. The evaluation of in vitro potencies of OA, DTX1 and DTX2 was performed by the protein phosphatase 2A (PP2A) inhibition assay. Results: Mice that received DSP toxins by gavage showed diarrhea as the main symptom. Those toxins caused similar gastrointestinal alterations as well as intestine ultrastructural changes. However, DSP toxins did not modify tight junctions to trigger diarrhea. They had different toxicokinetics and toxic potency. The lethal dose 50 (LD50) was 487 µg kg-1 bw for DTX1, 760 µg kg-1 bw for OA and 2262 µg kg-1 bw for DTX2. Therefore, the oral TEF values are: OA = 1, DTX1 = 1.5 and DTX2 = 0.3. Conclusion: This is the first comparative study of DSP toxins performed with accurate well-characterized standards and based on acute toxicity data. Results confirmed that DTX1 is more toxic than OA by oral route while DTX2 is less toxic. Hence, the current TEFs based on intraperitoneal toxicity should be modified. Also, the generally accepted toxic mode of action of this group of toxins needs to be reevaluated

De-genderating the teaching education in Physical Education

El presente artículo se enmarca en el proyecto de investigación “La buena enseñanza. Intervenciones docentes y evaluación en clave de géneros. Estudio en los Profesorados Universitarios de Educación Física de la UNLu y UdelaR”, de la Universidad Nacional de Luján, Argentina. El propósito es compartir un taller vivencial llevado a cabo en el “II Encuentro de Estudios en Deporte” de la Universidad de la República, Uruguay (UdelaR). Dicha instancia surge como necesidad de generar un espacio práctico de problematización e indagación sobre la educación física y su enseñanza con perspectiva de géneros en la trayectoria de la formación docente, con el objeto que los y las participantes practiquen, apropien y transfieran la perspectiva de géneros al desarrollo de sus prácticas docentes.The present article is framed in the research project “The good teaching. Teaching interventions and evaluation in the key of gender. Study in the undergraduate teaching training courses of UNLu and UdelaR”, of the Universidad Nacional de Luján, Argentina. The purpose is to share a living workshop which took place during the “II Encounter in Sports Studies” of the Universidad de la República, Uruguay (UdelaR). Such instance arises as a need to generate a practical space to problematize and inquire about Physical Education and the ways to teach it linked to the gender perspective in the trajectory in teaching training, with the objective that the participants practice, appropriate and transfer such gender perspective to their teaching practices.Facultad de Humanidades y Ciencias de la Educació

Crambescin C1 Acts as A Possible Substrate of iNOS and eNOS Increasing Nitric Oxide Production and Inducing In Vivo Hypotensive Effect

Crambescins are guanidine alkaloids from the sponge Crambe crambe. Crambescin C1 (CC) induces metallothionein genes and nitric oxide (NO) is one of the triggers. We studied and compared the in vitro, in vivo, and in silico effects of some crambescine A and C analogs. HepG2 gene expression was analyzed using microarrays. Vasodilation was studied in rat aortic rings. In vivo hypotensive effect was directly measured in anesthetized rats. The targets of crambescines were studied in silico. CC and homo-crambescine C1 (HCC), but not crambescine A1 (CA), induced metallothioneins transcripts. CC increased NO production in HepG2 cells. In isolated rat aortic rings, CC and HCC induced an endothelium-dependent relaxation related to eNOS activation and an endothelium-independent relaxation related to iNOS activation, hence both compounds increase NO and reduce vascular tone. In silico analysis also points to eNOS and iNOS as targets of Crambescin C1 and source of NO increment. CC effect is mediated through crambescin binding to the active site of eNOS and iNOS. CC docking studies in iNOS and eNOS active site revealed hydrogen bonding of the hydroxylated chain with residues Glu377 and Glu361, involved in the substrate recognition, and explains its higher binding affinity than CA. The later interaction and the extra polar contacts with its pyrimidine moiety, absent in the endogenous substrate, explain its role as exogenous substrate of NOSs and NO production. Our results suggest that CC serve as a basis to develop new useful drugs when bioavailability of NO is perturbed.Fil: Rubiolo, Juan Andrés. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Ministerio de Ciencia, Tecnologia E Innovacion Productiva (santa Fe). - Gobierno de la Provincia de Santa Fe. Ministerio de Ciencia, Tecnologia E Innovacion Productiva (santa Fe).; Argentina. Universidad de Santiago de Compostela; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Lence, Emilio. Universidad de Santiago de Compostela; EspañaFil: González Bello, Concepción. Universidad de Santiago de Compostela; EspañaFil: Roel, María. Universidad de Santiago de Compostela; EspañaFil: Gil Longo, José. Universidad de Santiago de Compostela; EspañaFil: Campos Toimil, Manuel. Universidad de Santiago de Compostela; EspañaFil: Ternon, Eva. Université Nice Sophia Antipolis. Laboratoire Jean-alexandre Dieudonné.; FranciaFil: Thomas, Olivier P.. National University of Ireland Galway; IrlandaFil: González Cantalapiedra, Antonio. Universidad de Santiago de Compostela; EspañaFil: López Alonso, Henar. Universidad de Santiago de Compostela; EspañaFil: Vieytes, Mercedes R.. Universidad de Santiago de Compostela; EspañaFil: Botana, Luis M.. Universidad de Santiago de Compostela; Españ