Mid-Infrared Observations of Planetary Nebulae detected in the GLIMPSE 3D Survey

We present mapping, profiles and photometry for 24 planetary nebulae (PNe) detected in the GLIMPSE 3D mid-infrared (MIR) survey of the Galactic plane. The PNe show many of the properties observed in previous studies of these sources, including evidence for longer wave emission from outside of the ionised zones, a likely consequence of emission from polycyclic aromatic hydrocarbons (PAHs) within the nebular photo-dissociation regimes (PDRs). We also note variations in 5.8/4.5 and 8.0/4.5 microns flux ratios with distance from the nuclei; present evidence for enhanced MIR emission in the halos of the sources; and note evidence for variations in colour with nebular evolution.Comment: 35 pages, 28 figures, Accepted for publication in Revista Mexicana de Astronomia y Astrofisica (RevMexAA). 61 pages in arXi

Determinación del Desbalance en Sistemas Rotor-cojinete a velocidad constante: Método de Identificación Algebraica

The development of a mathematical model for an on-line algebraic identifier is presented in this work. This model is used for determining the unbalance and its related angular position on vibrating rotor-dynamic systems of multiple degrees of freedom. The proposed identifier was obtained from the basis of a finite element mathematical model for rotating systems of multiple degrees of freedom. The model was developed under the consideration of four degrees of freedom beam-type element, where rotational inertia, gyroscopic moments, shearing strains and inner and outer damping effects were included. The on time behavior of proposed identifier was assessed for unbalance identification and its related angular position; the constant-speed unbalanced vibration response obtained from numerical simulation was used as input data

Unveiling the stellar origin of the Wolf-Rayet nebula NGC6888 through infrared observations

We present a comprehensive infrared (IR) study of the iconic Wolf-Rayet (WR) wind-blown bubble NGC6888 around WR136. We use Wide-field Infrared Survey Explorer (WISE), Spitzer IRAC and MIPS and Herschel PACS IR images to produce a sharp view of the distribution of dust around WR136. We complement these IR photometric observations with Spitzer IRS spectra in the 5-38 $\mu$m wavelength range. The unprecedented high-resolution IR images allowed us to produce a clean spectral energy distribution, free of contamination from material along the line of sight, to model the properties of the dust in NGC6888. We use the spectral synthesis code Cloudy to produce a model for NGC6888 that consistently reproduces its optical and IR properties. Our best model requires a double distribution with the inner shell composed only of gas, whilst the outer shell requires a mix of gas and dust. The dust consists of two populations of grain sizes, one with small sized grains $a_\mathrm{small}$=[0.002-0.008] $\mu$m and another one with large sized grains $a_\mathrm{big}$=[0.05-0.5] $\mu$m. The population of big grains is similar to that reported for other red supergiants stars and dominates the total dust mass, which leads us to suggest that the current mass of NGC6888 is purely due to material ejected from WR136, with a negligible contribution of swept up interstellar medium. The total mass of this model is 25.5$^{+4.7}_{-2.8}$ M$_{\odot}$, a dust mass of $M_\mathrm{dust}=$0.14$^{+0.03}_{-0.01}$ M$_{\odot}$, for a dust-to-gas ratio of $5.6\times10^{-3}$. Accordingly, we suggest that the initial stellar mass of WR136 was $\lesssim$50 M$_{\odot}$, consistent with current single stellar evolution models.Comment: 13 pages, 11 figures, 6 tables; Accepted to MNRA

Optical and Infrared Imaging and Spectroscopy of the Multiple-Shell Planetary Nebula NGC 6369

NGC 6369 is a double-shell planetary nebula (PN) consisting of a bright annular inner shell with faint bipolar extensions and a filamentary envelope. We have used ground- and space-based narrow-band optical and near-IR images, broad-band mid-IR images, optical long-slit echelle spectra, and mid-IR spectra to investigate its physical structure. These observations indicate that the inner shell of NGC 6369 can be described as a barrel-like structure shape with polar bubble-like protrusions, and reveal evidence for H2 and strong polycyclic aromatic hydrocarbons (PAHs) emission from a photo-dissociative region (PDR) with molecular inclusions located outside the bright inner shell. High-resolution HST narrow-band images reveal an intricate excitation structure of the inner shell and a system of "cometary" knots. The knotty appearance of the envelope, the lack of kinematical evidence for shell expansion and the apparent presence of emission from ionized material outside the PDR makes us suggest that the envelope of NGC 6369 is not a real shell, but a flattened structure at its equatorial regions. We report the discovery of irregular knots and blobs of diffuse emission in low-excitation and molecular line emission that are located up to 80" from the central star, well outside the main nebular shells. We also show that the filaments associated to the polar protrusions have spatial extents consistent with post-shock cooling regimes, and likely represent regions of interaction of these structures with surrounding material.Comment: 14 pages, 13 figures. Accepted for publication in MNRA

A Ribosomal Misincorporation of Lys for Arg in Human Triosephosphate Isomerase Expressed in Escherichia coli Gives Rise to Two Protein Populations

We previously observed that human homodimeric triosephosphate isomerase (HsTIM) expressed in Escherichia coli and purified to apparent homogeneity exhibits two significantly different thermal transitions. A detailed exploration of the phenomenon showed that the preparations contain two proteins; one has the expected theoretical mass, while the mass of the other is 28 Da lower. The two proteins were separated by size exclusion chromatography in 3 M urea. Both proteins correspond to HsTIM as shown by Tandem Mass Spectrometry (LC/ESI-MS/MS). The two proteins were present in nearly equimolar amounts under certain growth conditions. They were catalytically active, but differed in molecular mass, thermostability, susceptibility to urea and proteinase K. An analysis of the nucleotides in the human TIM gene revealed the presence of six codons that are not commonly used in E. coli. We examined if they were related to the formation of the two proteins. We found that expression of the enzyme in a strain that contains extra copies of genes that encode for tRNAs that frequently limit translation of heterologous proteins (Arg, Ile, Leu), as well as silent mutations of two consecutive rare Arg codons (positions 98 and 99), led to the exclusive production of the more stable protein. Further analysis by LC/ESI-MS/MS showed that the 28 Da mass difference is due to the substitution of a Lys for an Arg residue at position 99. Overall, our work shows that two proteins with different biochemical and biophysical properties that coexist in the same cell environment are translated from the same nucleotide sequence frame

Angular Expansion of Nova Shells

Nova shells can provide important information on their distance, their interactions with circumstellar and interstellar media, and the evolution in morphology of the ejecta. We have obtained narrowband images of a sample of five nova shells, namely DQ Her, FH Ser, T Aur, V476 Cyg, and V533 Her, with ages ranging from 50 to 130 yr. These images have been compared with suitable available archival images to derive their angular expansion rates. We find that all the nova shells in our sample are still in the free expansion phase, which can be expected, as the mass of the ejecta is 7-45 times larger than the mass of the swept-up circumstellar medium. The nova shells will keep expanding freely for time periods up to a few hundred years, reducing their time dispersal into the interstellar medium. © 2020. The American Astronomical Society. All rights reserved.E.S., G.R., and J.A.Q.M. acknowledge support from CONACyT and Universidad de Guadalajara. M.A.G. and E.S. acknowledge financial support by grants AYA 2014-57280-P and PGC 2018-102184-B-I00, cofunded with FEDER funds. M.A.G. acknowledges support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). E.S. acknowledges the hospitality of the IAA during a short-term visit. G.R.L. acknowledges support from CONACyT and PRODEP (Mexico). L.S. acknowledges support from UNAM DGAPA PAPIIT project IN101819. M.A.G. and J.A.T. acknowledge support from the UNAM DGAPA PAPIIT project IA 100318. We appreciate the valuable comments of the referee, Dr Nye Evans. Finally, we thank Alessandro Ederoclite for useful discussions and comments. The data presented here were obtained in part with ALFOSC, and provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA. This research made use of IRAF, distributed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. We acknowledge the use of the ESO Science Archive Facility developed in partnership with the Space Telescope European Coordinating Facility (ST-ECF). We also acknowledge the ING archive, maintained as part of the CASU Astronomical Data Centre at the Institute of Astronomy, Cambridge and finally, the STScI, operated by the Association of Universities for research in Astronomy, Inc., under NASA contract NAS5-26555.Peer reviewe

3D mapping of the Wolf-Rayet nebula M1-67: clues for post-common envelope evolution in massive stars

We present a 3D mapping of the Wolf-Rayet (WR) nebula M1-67 around WR124. We obtained high-resolution San Pedro M\'{a}rtir (SPM) Manchester Echelle Spectrograph (MES) observations along 17 long-slit positions covering all morphological features in M1-67. We are able to unveil the true morphology of M1-67 and its kinematics by interpreting the SPM MES observations by means of the 3D modelling tool for Astrophysics SHAPE. Our SHAPE model that best reproduces the SPM MES data includes three concentric bipolar structures composed by a hollow ellipsoidal structure and a torus. In addition, the model requires the presence of expanding jets and broken blisters in order to reproduce specific spectral features. Our results are consistent with the idea that M1-67 and its progenitor star WR124 have formed through a common envelope scenario that occurred 11.8$^{+4.6}_{-0.8}$ kyr ago. Our bipolar model strongly questions previous suggestions of the presence of a bow shock structure surrounding M1-67. We interpret that the bright structures detected in the spectra extracted from the central regions are produced by wind compression at the receding region of the innermost structure in M1-67. Furthermore, WR124 is moving through a low-density region above the Galactic plane that has negligibly affected the formation history of M1-67.Comment: 9 pages, 7 figures, 2 tables; Accepted to MNRA

Zika Virus: Knowledge Assessment of Residents and Health-Care Providers in Roatán, Honduras, following an Outbreak.

Few studies have evaluated the effectiveness of Zika virus (ZIKV) public health educational campaigns. Following a ZIKV educational campaign in Roatán, Honduras (October 2016), a survey was administered (March-May 2017) to residents (N = 348) and health-care professionals ([HCPs]; N = 44) to evaluate ZIKV knowledge, attitudes, and preventive practices, with attention to sexual health. Knowledge scores were calculated and mapped using participants' home locations. The knowledge scores between HCPs and residents were significantly different (mean 17 versus 11; P < 0.001). Only 6% of residents and 14% of HCPs knew that ZIKV was sexually transmissible. Few reported abstinence (2.6% residents; 9.4% HCPs) or condom use (1.6% residents; 12.5% HCPs) to prevent ZIKV infection. Of all subjects, 15.6% were pregnant or had a pregnant partner in the past year; 57.6% expressed concern over ZIKV. Mapping demonstrated spatial heterogeneity in knowledge. The findings suggest a need for improved public health messaging in ZIKV-affected areas

Unveiling the stellar origin of the Wolf-Rayet nebula NGC6888 through infrared observations

We present a comprehensive infrared (IR) study of the iconicWolf-Rayet (WR) wind-blown bubble NGC6888 around WR136. We use Wide-field Infrared Survey Explorer, Spitzer IRAC, and MIPS and Herschel PACS IR images to produce a sharp view of the distribution of dust around WR136. We complement these IR photometric observations with Spitzer IRS spectra in the 5-38-mu m wavelength range. The unprecedented high-resolution IR images allowed us to produce a clean spectral energy distribution, free of contamination from material along the line of sight, to model the properties of the dust in NGC6888. We use the spectral synthesis code CLOUDY to produce a model for NGC6888 that consistently reproduces its optical and IR properties. Our best model requires a double distribution with the inner shell composed only of gas, whilst the outer shell requires a mix of gas and dust. The dust consists of two populations of grain sizes, one with small-sized grains a(small) = [0.002-0.008] mu m and another one with large-sized grains a(big) = [0.05-0.5] mu m. The population of big grains is similar to that reported for other red supergiants stars and dominates the total dust mass, which leads us to suggest that the current mass of NGC6888 is purely due to material ejected from WR 136, with a negligible contribution of the swept up interstellar medium. The total mass of this model is 25.5(-2.8)+4.7 M-circle dot, a dust mass of M-dust = 0.14(-0.01)(+0.03) M circle dot, for a dust-to-gas ratio of 5.6 x 10(-3). Accordingly, we suggest that the initial stellar mass of WR 136 was less than or similar to 50 M-circle dot, consistent with current single stellar evolution models. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyThe authors are also thankful to J. Reyes-Perez for providing the CMFGEN model of WR 136. GR would like to thank S.J. Arthur and people at IRyA-UNAM for their support during the realization of this project. GR, ES and JAQ-M acknowledge support from Consejo Nacional de Ciencia y Tecnologia (CONACyT) for student scholarship. JAT, GR, and MAG are funded by UNAM DGAPA PAPIIT project IA100720. MAG acknowledges support of the Spanish Ministerio de Ciencia, Innovaci ' on y Universidades grant PGC2018-102184-B-I00, co-funded by FEDER funds. GR-L acknowledges support from CONACyT grant 263373 and PRODEP (Mexico). VMAGG acknowledges support from the Programa de Becas posdoctorales of DGAPA UNAM. This work makes use of IRAF, distributed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy under cooperative agreement with the National Science Foundation. This work makes use of Herschel, Spitzer, and WISE IR observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. The Spitzer Space Telescope was operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. WISE is a joint project of the University of California (Los Angeles, USA) and the JPL/Caltech, funded by NASA .Peer reviewe