BVRI Surface Photometry of Isolated Spiral Galaxies

A release of multicolor broad band (BVRI) photometry for a subsample of 44 isolated spirals drawn from the Catalogue of Isolated Galaxies (CIG) is presented. Total magnitudes and colors at various circular apertures, as well as some global structural/morphological parameters are estimated. Morphology is reevaluated through optical and sharp/filtered R band images, (B-I) color index maps, and archive near-IR JHK images from the Two-Micron Survey. The CAS structural parameters (Concentration, Asymmetry, and Clumpiness) were calculated from the images in each one of the bands. The fraction of galaxies with well identified optical/near-IR bars (SB) is 63%, while a 17% more shows evidence of weak or suspected bars (SAB). The sample average value of the maximum bar ellipticity is 0.4. Half of the galaxies in the sample shows rings. We identify two candidates for isolated galaxies with disturbed morphology. The structural CAS parameters change with the observed band, and the tendencies they follow with the morphological type and global color are more evident in the redder bands. In any band, the major difference between our isolated spirals and a sample of interacting spirals is revealed in the A-S plane. A deep and uniformly observed sample of isolated galaxies is intended for various purposes including (i) comparative studies of environmental effects, (ii) confronting model predictions of galaxy evolution and (iii) evaluating the change of galaxy properties with redshift.Comment: 44 pages, 9 figures and 7 tables included. To appear in The Astronomical Journal. For the 43 appendix figures 4.1-4.43 see http://www.astroscu.unam.mx/~avila/Figs4.1_4.43.tar.gz (7.2 Mb tar.gz file

Emanation Study of Gas Radon on the Ancient Cuexcomate Geyser in Puebla City, Mexico

Radon measurements were collected over a period of nine months in the area of the ancient Cuexcomate geyser, in Puebla City. For measuring radon, the passive method of nuclear tracks in solids was used, using polycarbonate CR-39 as radiation sensitive material. Radon concentrations varied in strong anti-correlation with the rainfall intensity. And are lower compared to other locations, in concordance with the stratigraphic composition, as travertine and deposits of volcanic origin, corresponding to the geyser chemical composition and the active environment in the north part of the Trans-Mexican Volcanic Belt with an andesitic and basalt composition

A sensitivity analysis of the WFCAM Transit Survey for short-period giant planets around M dwarfs

The WFCAM Transit Survey (WTS) is a near-infrared transit survey running on the United Kingdom Infrared Telescope (UKIRT), designed to discover planets around M dwarfs. The WTS acts as a poor-seeing backup programme for the telescope, and represents the first dedicated wide-field near-infrared transit survey. In this paper we describe the observing strategy of the WTS and the processing of the data to generate lightcurves. We describe the basic properties of our photometric data, and measure our sensitivity based on 950 observations. We show that the photometry reaches a precision of ~4mmag for the brightest unsaturated stars in lightcurves spanning almost 3 years. Optical (SDSS griz) and near-infrared (UKIRT ZYJHK) photometry is used to classify the target sample of 4600 M dwarfs with J magnitudes in the range 11-17. Most have spectral-types in the range M0-M2. We conduct Monte Carlo transit injection and detection simulations for short period (<10 day) Jupiter- and Neptune-sized planets to characterize the sensitivity of the survey. We investigate the recovery rate as a function of period and magnitude for 4 hypothetical star-planet cases: M0-2+Jupiter, M2-4+Jupiter, M0-2+Neptune, M2-4+Neptune. We find that the WTS lightcurves are very sensitive to the presence of Jupiter-sized short-period transiting planets around M dwarfs. Hot Neptunes produce a much weaker signal and suffer a correspondingly smaller recovery fraction. Neptunes can only be reliably recovered with the correct period around the rather small sample (~100) of the latest M dwarfs (M4-M9) in the WTS. The non-detection of a hot-Jupiter around an M dwarf by the WFCAM Transit Survey allows us to place an upper limit of 1.7-2.0 per cent (at 95 per cent confidence) on the planet occurrence rate.Comment: 20 pages, 13 figures; accepted for publication in MNRA

Nuclear Tracks Morphology Study Using Raman Methodology

In this work, a new methodology for rendering profiles of etched nuclear tracks is presented, using confocal micro-Raman spectrometry instrumentation. The precise profile of etched nuclear tracks with normal and/or angular incidence of the particle can be determined in few minutes, with a great visual and numerical resolution, that means a quantitative and qualitative simultaneous chemical and morphology characterization with the Raman technique. The Raman image routine is designed to acquire at each image pixel a complete Raman spectrum. This is a mapping of the functional groups that form the polymeric structure, which may be broken by the damage caused by the incident radiation and/or the etching process

Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light curves using the difference-imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision achieved with both methods. The results show that differencephotometry light curves present an important improvement for stars with J > 16. We report an implementation on the box-fitting transit detection algorithm, which performs a trapezoid-fit to the folded light curve, providing more accurate results than the boxfitting model. We describe and optimize a set of selection criteria to search for transit candidates, including the V-shape parameter calculated by our detection algorithm. The optimized selection criteria are applied to the aperture photometry and difference-imaging light curves, resulting in the automatic detection of the best 200 transit candidates from a sample of ~475 000 sources. We carry out a detailed analysis in the 18 best detections and classify them as transiting planet and eclipsing binary candidates. We present one planet candidate orbiting a late G-type star. No planet candidate around M-stars has been found, confirming the null detection hypothesis and upper limits on the occurrence rate of short-period giant planets around M-dwarfs presented in a prior study. We extend the search for transiting planets to stars with J ≤ 18, which enables us to set a stricter upper limit of 1.1%. Furthermore, we present the detection of five faint extremely-short period eclipsing binaries and three M-dwarf/M-dwarf binary candidates. The detections demonstrate the benefits of using the difference-imaging light curves, especially when going to fainter magnitudes.Peer reviewe

Documentación sobre la convivencia con el agua en el Valle y la Sierra de Ahuisculco

“San Pedro de Valencia: renovación urbana, saneamiento ambiental y emprendimientos turísticos” es un proyecto activo que mantiene el ITESO en el Valle de Mazatepec, ubicado a unos 42 km de Guadalajara. La idea del proyecto es darle acompañamiento a una sociedad que buscó ayuda para poder denunciar los malos usos del agua en la zona, y las afectaciones que este descuido les ha traído, por ejemplo, al sector turístico, del cual, dependen muchas familias. Dentro del PAP se crean subproyectos. Primero, para dirigir a los estudiantes a los proyectos correspondientes según su área de conocimiento, y segundo, para poder dar atención a problemas más específicos. Para verano 2021, el equipo que escribe se encargó del proyecto Agua Social. La idea de este subproyecto consistió en recolectar la mayor cantidad de información y datos posibles a través de entrevistas con actores clave del Valle. También poder registrar el sentir de distintas personas locales respecto a la problemática del agua. Esto para poder reflexionar si el proyecto es funcional para la comunidad. La recolección de información y datos se llevó a cabo para sintetizarla y convertirla en productos pedagógicos, para después, a través de distintos mecanismos de organización de las comunidades, divulgarla para que llegue a los pobladores, con el fin de empoderarlos y que sus decisiones sean informadas, que las usen como lucha para defender sus recursos. Se confirmó la hipótesis con la que se empezó el proyecto: sobreexplotación del agua, su contaminación y la desinformación alrededor del problema, además de pocas oportunidades para los pobladores ante el panorama.ITESO, A.C

Four ultra-short period eclipsing M-dwarf binaries in the WFCAM Transit Survey

We report on the discovery of four ultra-short period (P<0.18 days) eclipsing M-dwarf binaries in the WFCAM Transit Survey. Their orbital periods are significantly shorter than of any other known main-sequence binary system, and are all significantly below the sharp period cut-off at P~0.22 days as seen in binaries of earlier type stars. The shortest-period binary consists of two M4 type stars in a P=0.112 day orbit. The binaries are discovered as part of an extensive search for short-period eclipsing systems in over 260,000 stellar lightcurves, including over 10,000 M-dwarfs down to J=18 mag, yielding 25 binaries with P<0.23 days. In a popular paradigm, the evolution of short period binaries of cool main-sequence stars is driven by loss of angular momentum through magnetised winds. In this scheme, the observed P~0.22 day period cut-off is explained as being due to timescales that are too long for lower-mass binaries to decay into tighter orbits. Our discovery of low-mass binaries with significantly shorter orbits implies that either these timescales have been overestimated for M-dwarfs, e.g. due to a higher effective magnetic activity, or that the mechanism for forming these tight M-dwarf binaries is different from that of earlier type main-sequence stars.Comment: 22 pages, 17 figures, 3 tables Accepted for publication in MNRA

Understanding amine catalyzed silica polymerization : diatoms as bioarchitects.

Current state-of-the-art biomimetic methodologies employed worldwide for the realization of self-assembled nanomaterials are adequate for certain unique applications, but a major breakthrough is needed if these nanomaterials are to obtain their true promise and potential. These routes typically utilize a 'top-down' approach in terms of controlling the nucleation, growth, and deposition of structured nanomaterials. Most of these techniques are inherently limited to primarily 2D and simple 3D structures, and are therefore limited in their ultimate functionality and field of use. Zeolites, one of the best-known and understood synthetic silica structures, typically possess highly ordered silica domains over very small length scales. The development of truly organized and hierarchical zeolites over several length scales remains an intense area of research world wide. Zeolites typically require high-temperature and complex synthesis routes that negatively impact certain economic parameters and, therefore, the ultimate utility of these materials. Nonetheless, zeolite usage is in the tons per year worldwide and is quickly becoming ubiquitous in its applications. In addition to these more mature aspects of current practices in materials science, one of the most promising fields of nanotechnology lies in the advent and control of biologically self-assembled materials, especially those involved with silica and other ceramics such as hydroxyapatite. Nature has derived, through billions of years of evolutionary steps, numerous methods by which fault-tolerant and mechanically robust structures can be created with exquisite control and precision at relatively low temperature ranges and pressures. Diatoms are one of the best known examples that exhibit this degree of structure and control known that is involved with the biomineralization of silica. Diatoms are eukaryotic algae that are ubiquitous in marine and freshwater environments. They are a dominant form of phytoplankton critical to global carbon fixation. The silicified cell wall of the diatom is called the frustule, and the intricate silica structure characteristic of a given species is known as the valve. There are two general classes of diatoms, based on their overall morphologies, the pennate and centric. Diatoms achieve their silicified structures in exact fashion through genetically inspired design rules coupled with precisely directed biochemistry occurring at temperatures ranging from a few degrees Celsius (polar species) to temperatures just over room temperature (tropical species). Different species of diatoms produce markedly different structures. To start with, there are two basic types of frustule macromorphologies: pennate diatoms display bilateral symmetry and centric diatoms show radial symmetry. There are thousands of permutations of these two basic forms and the micromorphology of the valve can be quite complex with all types of pore arrangements and morphologies (Figure 1.1). The detailed morphology of the cell wall of a given diatom species is reproduced with exactness, because the process is genetically encoded. Three types of cell wall proteins have been identified in diatoms; the frustulins, pleuralins, and silaffins. Frustulins are cell wall proteins that form an organic coat to protect the silica structures from dissolution into the aqueous environment. Pleuralins are associated with a specific subcomponent of the frustule during cell division, and play a role in hypotheca-epitheca development. Silaffins from Cylindrotheca fusiformis are short chain-length peptides that play a direct role in the silica polymerization process, and possess unique biochemical post-translation functionalization. Larger proteins with silaffin activity have recently been described in Thalassiosira pseudonana. Frustulins and pleuralins play no role in silica polymerization or structure formation in diatoms, whereas the silaffins are one of the primary polymerization determinants. In addition to the silaffins, a class of long-chain polyamines associated with diatom silica has been identified, and shown to also be involved in the silica polymerization process. The silaffins and polyamines are likely to be the two major determinants of silica polymerization in diatoms. Their involvement in the formation of higher order structure is unclear; there have been suggestions that they self-assemble in various combinations to form the final frustule structure but these are highly speculative as there is no substantial data to support this. It is clear from a long history of electron microscopic observations that a major determinant of silica structure in diatoms is generated by growth and molding of the silica deposition vesicle (SDV), the specialized intracellular compartment were the frustule is made. Diatoms are the focus of research activity on several fronts, including the processes by which their distinct silica frustules are formed

Zoonotic helminths of dogs and risk factors associated with polyparasitism in Grenada, West Indies

Canine soil-transmitted helminths (STHs) cause important zoonoses in the tropics, with varying degrees of intensity of infection in humans and dogs. This study aimed to investigate the prevalence and associated risk factors for STHs in community dogs residing in Grenada, West Indies. In May 2021, 232 canine fecal samples were examined for zoonotic helminths by microscopy (following flotation), and genomic DNA from a subset of 211 of these samples were subjected to multiplex qPCR for the detection and specific identification of hookworms, Toxocara spp. and Strongyloides. Microscopic examination revealed that 46.5% (108/232, 95% CI 40–52.9), 9% (21/232, 95% CI 5.35–12.7) and 5.2% (12/232, 95% CI 2.3–8) of the samples contained eggs of Ancylostoma spp., Toxocara spp. and Trichuris vulpis, respectively. Multiplex qPCR revealed that, 42.2% (89/211, 95% CI 35.5–48.8) were positive for at least 1 zoonotic parasite. Of these, 40.8% (86/211, 95% CI 34.1–47.3) of samples tested positive for Ancylostoma spp., 36% (76/211, 95% CI 29.5–42.9) were positive for A. caninum, 13.3% (28/211, 95% CI 9–18.6) for A. ceylanicum, 5.7% for T. canis (12/211, 95% CI 2.97–8.81) and 1% (2/211, 95% CI 0–2.26) for Strongyloides spp. (identified as S. stercoralis and S. papillosus by conventional PCR-based Sanger sequencing). Using a multiple logistic regression model, a low body score and free-roaming behaviour were significant predictors of test-positivity for these parasitic nematodes in dogs (P < 0.05). Further studies of zoonotic STHs in humans should help elucidate the public health relevance of these parasites in Grenada

Stellar Coronal and Wind Models: Impact on Exoplanets

Surface magnetism is believed to be the main driver of coronal heating and stellar wind acceleration. Coronae are believed to be formed by plasma confined in closed magnetic coronal loops of the stars, with winds mainly originating in open magnetic field line regions. In this Chapter, we review some basic properties of stellar coronae and winds and present some existing models. In the last part of this Chapter, we discuss the effects of coronal winds on exoplanets.Comment: Chapter published in the "Handbook of Exoplanets", Editors in Chief: Juan Antonio Belmonte and Hans Deeg, Section Editor: Nuccio Lanza. Springer Reference Work