Chemical Features in the Circumnuclear Disk of the Galactic Center

The circumnuclear disk (CND) of the Galactic Center is exposed to many energetic phenomena coming from the supermassive black hole Sgr A* and stellar activities. These energetic activities can affect the chemical composition in the CND by the interaction with UV-photons, cosmic-rays, X-rays, and shock waves. We aim to constrain the physical conditions present in the CND by chemical modeling of observed molecular species detected towards it. We analyzed a selected set of molecular line data taken toward a position in the southwest lobe of the CND with the IRAM 30m and APEX 12-meter telescopes and derived the column density of each molecule using a large velocity gradient (LVG) analysis. The determined chemical composition is compared with a time-dependent gas-grain chemical model based on the UCL\_CHEM code that includes the effects of shock waves with varying physical parameters. Molecules such as CO, HCN, HCO$^+$, HNC, CS, SO, SiO, NO, CN, H$_2$CO, HC$_3$N, N$_2$H$^+$ and H$_3$O$^+$ are detected and their column densities are obtained. Total hydrogen densities obtained from LVG analysis range between $2 \times 10^4$ and $1 \times 10^6\,$cm$^{-3}$ and most species indicate values around several $\times 10^5\,$cm$^{-3}$, which are lower than values corresponding to the Roche limit, which shows that the CND is tidally unstable. The chemical models show good agreement with the observations in cases where the density is $\sim10^4\,$cm$^{-3}$, the cosmic-ray ionization rate is high, $>10^{-15} \,$s$^{-1}$, or shocks with velocities $> 40\,$km s$^{-1}$ have occurred. Comparison of models and observations favors a scenario where the cosmic-ray ionization rate in the CND is high, but precise effects of other factors such as shocks, density structures, UV-photons and X-rays from the Sgr A* must be examined with higher spatial resolution data.Comment: 17 Pages, 13 figures, accepted for publication in A&

On the phenomenological classification of continuum radio spectra variability patterns of Fermi blazars

The F-GAMMA program is a coordinated effort to investigate the physics of Active Galactic Nuclei (AGNs) via multi-frequency monitoring of {\em Fermi} blazars. The current study is concerned with the broad-band radio spectra composed of measurement at ten frequencies between 2.64 and 142 GHz. It is shown that any of the 78 sources studied can be classified in terms of their variability characteristics in merely 5 types of variability. The first four types are dominated by spectral evolution and can be reproduced by a simple two-component system made of the quiescent spectrum of a large scale jet populated with a flaring event evolving according to Marscher & Gear (1985). The last type is characterized by an achromatic change of the broad-band spectrum which must be attributed to a completely different mechanism. Here are presented, the classification, the assumed physical system and the results of simulations that have been conducted.Comment: 2011 Fermi Symposium proceedings - eConf C11050

Presupuestos participativos en la comuna de San Pedro de la Paz : Un análisis reflexivo de la metodología participativa impulsada por el gobierno local

Al igual que en Europa y América Latina, Chile ha sido testigo del llamado de sus autoridades a facilitar el acceso a la participación de la ciudadanía en la gestión local y el ejercicio del control en los gastos de la actividad en las instituciones públicas, basando esta intencionalidad en el diálogo y el establecimiento de herramientas y normativas propiciadas desde el sistema institucional tradicional, para la generación de confianza y adherencia de la población a una experiencia democrática más próxima a su realidad cotidiana, todo lo cual ha estado marcado por un desencanto y descredito hacia la política y la clase que la sostiene a nivel nacional. El presente trabajo, se enmarca dentro de un acuerdo de colaboración entre el Departamento de Ciencias Sociales de la Universidad Católica de la Santísima Concepción y la Municipalidad de San Pedro de la Paz, ubicada en la provincia de Concepción, de la región del Bío-Bío en Chile. Dicho acuerdo, se establece por la necesidad, expresada desde el municipio, para reflexionar e investigar el desarrollo de las estrategias y acciones implementadas con el fin de generar un mayor nivel de participación ciudadana en los habitantes de la comuna. Como un primer paso hacia el desafío planteado en este compromiso, se realizó una revisión documental de los registros e informes que la Dirección de Desarrollo Comunitario del municipio (en adelante DIDECO), estaba generando en torno a la implementación de los Presupuestos Participativos (en adelante PP), lo cual fue complementado con entrevistas en profundidad semiestructuradas, que se realizaron a la directora de la DIDECO y algunos integrantes del equipo técnico que coordina los trabajos territoriales de las acciones participativas que se han ejecutado. Con ello, se ha pretendido establecer la base para desarrollar un proyecto de investigación que explore los aspectos que permitan analizar el impacto de la estrategia de promoción de la participación municipal, en los ciudadanos de la comuna.Facultad de Humanidades y Ciencias de la Educació

Presupuestos participativos en la comuna de San Pedro de la Paz : Un análisis reflexivo de la metodología participativa impulsada por el gobierno local

Al igual que en Europa y América Latina, Chile ha sido testigo del llamado de sus autoridades a facilitar el acceso a la participación de la ciudadanía en la gestión local y el ejercicio del control en los gastos de la actividad en las instituciones públicas, basando esta intencionalidad en el diálogo y el establecimiento de herramientas y normativas propiciadas desde el sistema institucional tradicional, para la generación de confianza y adherencia de la población a una experiencia democrática más próxima a su realidad cotidiana, todo lo cual ha estado marcado por un desencanto y descredito hacia la política y la clase que la sostiene a nivel nacional. El presente trabajo, se enmarca dentro de un acuerdo de colaboración entre el Departamento de Ciencias Sociales de la Universidad Católica de la Santísima Concepción y la Municipalidad de San Pedro de la Paz, ubicada en la provincia de Concepción, de la región del Bío-Bío en Chile. Dicho acuerdo, se establece por la necesidad, expresada desde el municipio, para reflexionar e investigar el desarrollo de las estrategias y acciones implementadas con el fin de generar un mayor nivel de participación ciudadana en los habitantes de la comuna. Como un primer paso hacia el desafío planteado en este compromiso, se realizó una revisión documental de los registros e informes que la Dirección de Desarrollo Comunitario del municipio (en adelante DIDECO), estaba generando en torno a la implementación de los Presupuestos Participativos (en adelante PP), lo cual fue complementado con entrevistas en profundidad semiestructuradas, que se realizaron a la directora de la DIDECO y algunos integrantes del equipo técnico que coordina los trabajos territoriales de las acciones participativas que se han ejecutado. Con ello, se ha pretendido establecer la base para desarrollar un proyecto de investigación que explore los aspectos que permitan analizar el impacto de la estrategia de promoción de la participación municipal, en los ciudadanos de la comuna.Facultad de Humanidades y Ciencias de la Educació

F-GAMMA: On the phenomenological classification of continuum radio spectra variability patterns of Fermi blazars

The F-GAMMA program is a coordinated effort to investigate the physics of Active Galactic Nuclei (AGNs) via multi-frequency monitoring of Fermi blazars. In the current study we show and discuss the evolution of broad-band radio spectra, which are measured at ten frequencies between 2.64 and 142 GHz using the Effelsberg 100-m and the IRAM 30-m telescopes. It is shown that any of the 78 sources studied can be classified in terms of their variability characteristics in merely 5 types of variability. It is argued that these can be attributed to only two classes of variability mechanisms. The first four types are dominated by spectral evolution and can be described by a simple two-component system composed of: (a) a steep quiescent spectral component from a large scale jet and (b) a time evolving flare component following the "Shock-in-Jet" evolutionary path. The fifth type is characterised by an achromatic change of the broad band spectrum, which could be attributed to a different mechanism, likely involving differential Doppler boosting caused by geometrical effects. Here we present the classification, the assumed physical scenario and the results of calculations that have been performed for the spectral evolution of flares.Comment: Proceedings of the conference: "The Central Kiloparsec in Galactic Nucleic: Astronomy at High Angular Resolution 2011", August 29 - September 2, 2011, Bad Honnef, German

An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance

On June 20, 2017, members of the environmental engineering and science (EES) community convened at the Association of Environmental Engineering and Science Professors (AEESP) Biennial Conference for a workshop on antimicrobial resistance. With over 80 registered participants, discussion groups focused on the following topics: risk assessment, monitoring, wastewater treatment, agricultural systems, and synergies. In this study, we summarize the consensus among the workshop participants regarding the role of the EES community in understanding and mitigating the spread of antibiotic resistance via environmental pathways. Environmental scientists and engineers offer a unique and interdisciplinary perspective and expertise needed for engaging with other disciplines such as medicine, agriculture, and public health to effectively address important knowledge gaps with respect to the linkages between human activities, impacts to the environment, and human health risks. Recommendations that propose priorities for research within the EES community, as well as areas where interdisciplinary perspectives are needed, are highlighted. In particular, risk modeling and assessment, monitoring, and mass balance modeling can aid in the identification of “hot spots” for antibiotic resistance evolution and dissemination, and can help identify effective targets for mitigation. Such information will be essential for the development of an informed and effective policy aimed at preserving and protecting the efficacy of antibiotics for future generations

Evaluating the impact of sex-biased genetic admixture in the americas through the analysis of haplotype data

A general imbalance in the proportion of disembarked males and females in the Americas has been documented during the Trans-Atlantic Slave Trade and the Colonial Era and, although less prominent, more recently. This imbalance may have left a signature on the genomes of modern-day populations characterised by high levels of admixture. The analysis of the uniparental systems and the evaluation of continental proportion ratio of autosomal and X chromosomes revealed a general sex imbalance towards males for European and females for African and Indigenous American ancestries. However, the consistency and degree of this imbalance are variable, suggesting that other factors, such as cultural and social practices, may have played a role in shaping it. Moreover, very few investigations have evaluated the sex imbalance using haplotype data, containing more critical information than genotypes. Here, we analysed genome-wide data for more than 5000 admixed American individuals to assess the presence, direction and magnitude of sex-biased admixture in the Americas. For this purpose, we applied two haplotype-based approaches, ELAI and NNLS, and we compared them with a genotype-based method, ADMIXTURE. In doing so, besides a general agreement between methods, we unravelled that the post-colonial admixture dynamics show higher complexity than previously described

Molecular and Electrophysiological Characterization of a Novel Cation Channel of Trypanosoma cruzi

We report the identification, functional expression, purification, reconstitution and electrophysiological characterization of a novel cation channel (TcCat) from Trypanosoma cruzi, the etiologic agent of Chagas disease. This channel is potassium permeable and shows inward rectification in the presence of magnesium. Western blot analyses with specific antibodies indicated that the protein is expressed in the three main life cycle stages of the parasite. Surprisingly, the parasites have the unprecedented ability to rapidly change the localization of the channel when they are exposed to different environmental stresses. TcCat rapidly translocates to the tip of the flagellum when trypomastigotes are submitted to acidic pH, to the plasma membrane when epimastigotes are submitted to hyperosmotic stress, and to the cell surface when amastigotes are released to the extracellular medium. Pharmacological block of TcCat activity also resulted in alterations in the trypomastigotes ability to respond to hyperosmotic stress. We also demonstrate the feasibility of purifying and reconstituting a functional ion channel from T. cruzi after recombinant expression in bacteria. The peculiar characteristics of TcCat could be important for the development of specific inhibitors with therapeutic potential against trypanosomes

The VLT-FLAMES Tarantula survey XX. The nature of the X-ray bright emission-line star VFTS 399

Context. The stellar population of the 30 Doradus star-forming region in the Large Magellanic Cloud contains a subset of apparently single, rapidly rotating O-type stars. The physical processes leading to the formation of this cohort are currently uncertain. Aims. One member of this group, the late O-type star VFTS 399, is found to be unexpectedly X-ray bright for its bolometric luminosity − in this study we aim to determine its physical nature and the cause of this behaviour. Methods. To accomplish this we performed a time-resolved analysis of optical, infrared and X-ray observations. Results. We found VFTS 399 to be an aperiodic photometric variable with an apparent near-IR excess. Its optical spectrum demonstrates complex emission profiles in the lower Balmer series and select He i lines − taken together these suggest an OeBe classification. The highly variable X-ray luminosity is too great to be produced by a single star, while the hard, non-thermal nature suggests the presence of an accreting relativistic companion. Finally, the detection of periodic modulation of the X-ray lightcurve is most naturally explained under the assumption that the accretor is a neutron star. Conclusions. VFTS 399 appears to be the first high-mass X-ray binary identified within 30 Dor, sharing many observational characteristics with classical Be X-ray binaries. Comparison of the current properties of VFTS 399 to binary-evolution models suggests a progenitor mass ≳25 M⊙ for the putative neutron star, which may host a magnetic field comparable in strength to those of magnetars. VFTS 399 is now the second member of the cohort of rapidly rotating “single” O-type stars in 30 Dor to show evidence of binary interaction resulting in spin-up, suggesting that this may be a viable evolutionary pathway for the formation of a subset of this stellar population