An Asymmetric Keplerian Disk Surrounding the O-type Protostar IRAS 16547-4247

For the past few decades, there has been great interest in determining if even the most massive stars in our galaxy (namely the spectral O-type stars) are formed in a similar manner as the low- and intermediate-mass stars, that is, through the presence of accreting disks and powerful outflows. Here, using sensitive observations of the Atacama Large Millimeter/Submillimeter Array, we report a resolved Keplerian disk (with 15 synthesized beams across its major axis) surrounding the deeply embedded O-type protostar IRAS 16547-4247. The disk shows some asymmetries that could arise because the disk is unstable and fragmenting or because of different excitation conditions within the disk. The enclosed mass estimated from the disk Keplerian radial velocities is 25 -3 M . The molecular disk is at the base of an ionized thermal radio jet and is approximately perpendicular to the jet axis orientation. We additionally find the existence of a binary system of compact dusty objects at the center of the accreting disk, which indicates the possible formation of an O-type star and a companion of lower mass. This is not surprising due to the high binary fraction reported in massive stars. Subtracting the contribution of the dusty disk plus the envelope and the companion, we estimated a mass of 20 M for the central star.Fil: Zapata, Luis A.. Universidad Nacional Autónoma de México; MéxicoFil: Garay, Guido. Universidad de Chile; ChileFil: Palau, Aina. Universidad Nacional Autónoma de México; MéxicoFil: Rodríguez, Luis F.. Universidad Nacional Autónoma de México; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Estalella, Robert. Universidad de Barcelona; EspañaFil: Guzmán, Andres. National Astronomical Observatory of Japan; Japó

On the dynamics of the Zanzibar Channel

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 6091–6113, doi:10.1002/2015JC010879.The Zanzibar Channel lies between the mainland of Tanzania and Zanzibar Island in the tropical western Indian Ocean, is about 100 km long, 40 km wide, and 40 m deep, and is essential to local socioeconomic activities. This paper presents a model of the seasonal and tidal dynamics of the Zanzibar Channel based on the Regional Ocean Modeling System (ROMS) and a comparison of the model and observations. The seasonal dynamics of the channel is forced by remote processes and the local wind. Remote forcing creates the East African Coastal Current, a portion of which flows through the channel northward with a seasonally varying magnitude. The local wind enhances this seasonality in the surface Ekman layer, resulting in a stronger northward flow during the southwest monsoon season and a weak northward or occasionally southward flow during the northeast monsoon season. The tidal flows converge and diverge in the center of the channel and reduce the transport in the channel. The remotely forced, wind-forced, and tidal dynamics contain 5%, 3%, and 92% of the total kinetic energy, respectively. Despite their low kinetic energy, the remotely forced and wind-forced flows are most relevant in advecting channel water to the open ocean, which occurs in 19 days at the peak of the southwest monsoon season. The channel is well mixed, except during brief periods in the two rainy seasons, and temporarily cools between December and February. The dispersion of passive tracers is presented as an example of potential model applications.National Science Foundation Grant Numbers: OISE-0827059 , OCE-0550658 , OCE-0851493 , OCE-09274722016-03-1

Response to "Toward Unified Satellite Climatology of Aerosol Properties. 3. MODIS Versus MISR Versus AERONET"

A recent paper by Mishchenko et al. compares near-coincident MISR, MODIS, and AERONET aerosol optical depth (AOD) products, and reports much poorer agreement than that obtained by the instrument teams and others. We trace the reasons for the discrepancies primarily to differences in (1) the treatment of outliers, (2) the application of absolute vs. relative criteria for testing agreement, and (3) the ways in which seasonally varying spatial distributions of coincident retrievals are taken into account

The environments of hyper-compact H II regions. I. G345.0061+01.794 B

We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of CH3CN and SO2 and of the H29a radio recombination line towards the G345.0061+01.794 B HC H II region, in order to investigate the physical and kinematical characteristics of its surroundings. Emission was detected in all observed components of the J=14-13 rotational ladder of CH3CN and in the 30(4,26)-30(3,27) and 32(4,28)-32(3,29) lines of SO2. The peak of the velocity integrated molecular emission is located \sim0.4" northwest of the peak of the continuum emission. The first-order moment images and channel maps show a velocity gradient, of 1.1 km s-1 arcsec-1, across the source, and a distinctive spot of blueshifted emission towards the peak of the zero-order moment. We derived that the rotational temperature decreases from 230 Kelvin at the peak position to 137 Kelvin at its edge, indicating that our molecular observations are probing a hot molecular core that is internally excited. The emission in the H29a line arises from a region of 0.65" in size, whose peak is coincident with that of the dust continuum, has a center velocity of -18.1pm0.9 km s-1 and a width (FWHM) of 33.7pm2.3 km s-1. We modeled the kinematical characteristics of "central blue spot" feature as due to infalling motions, deriving a central mass of 126.0pm8.7M_sun. Our observations indicate that this HC H II region is surrounded by a compact structure of hot molecular gas, which is rotating and infalling toward a central mass, that is most likely confining the ionized region.Comment: 9 pages, 10 figures. Submitted to MNRA

Merging regional and global aerosol optical depth records from major available satellite products

Satellite instruments provide a vantage point for studying aerosol loading consistently over different regions of the world. However, the typical lifetime of a single satellite platform is on the order of 5-15 years; thus, for climate studies, the use of multiple satellite sensors should be considered. Discrepancies exist between aerosol optical depth (AOD) products due to differences in their information content, spatial and temporal sampling, calibration, cloud masking, and algorithmic assumptions. Users of satellite-based AOD time-series are confronted with the challenge of choosing an appropriate dataset for the intended application. In this study, 16 monthly AOD products obtained from different satellite sensors and with different algorithms were inter-compared and evaluated against Aerosol Robotic Network (AERONET) monthly AOD. Global and regional analyses indicate that products tend to agree qualitatively on the annual, seasonal and monthly timescales but may be offset in magnitude. Several approaches were then investigated to merge the AOD records from different satellites and create an optimised AOD dataset. With few exceptions, all merging approaches lead to similar results, indicating the robustness and stability of the merged AOD products. We introduce a gridded monthly AOD merged product for the period 1995-2017. We show that the quality of the merged product is as least as good as that of individual products. Optimal agreement of the AOD merged product with AERONET further demonstrates the advantage of merging multiple products. This merged dataset provides a long-term perspective on AOD changes over different regions of the world, and users are encouraged to use this dataset

Some Remarks on Theories with Large Compact Dimensions and TeV-Scale Quantum Gravity

We comment on some implications of theories with large compactification radii and TeV-scale quantum gravity. These include the behavior of high-energy gravitational scattering cross sections and consequences for ultra-high-energy cosmic rays and neutrino scattering, the question of how to generate naturally light neutrino masses, the issue of quark-lepton unification, the equivalence principle, and the cosmological constant.Comment: 28 pages, Late

Pan-RAF and MEK vertical inhibition enhances therapeutic response in non-V600 BRAF mutant cells

BACKGROUND: Currently, there are no available targeted therapy options for non-V600 BRAF mutated tumors. The aim of this study was to investigate the effects of RAF and MEK concurrent inhibition on tumor growth, migration, signaling and apoptosis induction in preclinical models of non-V600 BRAF mutant tumor cell lines. METHODS: Six BRAF mutated human tumor cell lines CRL5885 (G466 V), WM3629 (D594G), WM3670 (G469E), MDAMB231 (G464 V), CRL5922 (L597 V) and A375 (V600E as control) were investigated. Pan-RAF inhibitor (sorafenib or AZ628) and MEK inhibitor (selumetinib) or their combination were used in in vitro viability, video microscopy, immunoblot, cell cycle and TUNEL assays. The in vivo effects of the drugs were assessed in an orthotopic NSG mouse breast cancer model. RESULTS: All cell lines showed a significant growth inhibition with synergism in the sorafenib/AZ628 and selumetinib combination. Combination treatment resulted in higher Erk1/2 inhibition and in increased induction of apoptosis when compared to single agent treatments. However, single selumetinib treatment could cause adverse therapeutic effects, like increased cell migration in certain cells, selumetinib and sorafenib combination treatment lowered migratory capacity in all the cell lines. Importantly, combination resulted in significantly increased tumor growth inhibition in orthotropic xenografts of MDAMB231 cells when compared to sorafenib - but not to selumetinib - treatment. CONCLUSIONS: Our data suggests that combined blocking of RAF and MEK may achieve increased therapeutic response in non-V600 BRAF mutant tumors

Social intervention for an articulated execution of research projects in high Andean communities: Case of installation of the real-time monitoring system of the Arhuay- cocha glacier lake, Cordillera Blanca

In Peru, the communities located along the Andes Mountains at more than 3000 meters above sea level, have a behavior highly susceptible to any type of research activity on the mountain areas, mainly due to the past wrong management of mountain resources by mining companies for many decades, without an eco-efficient or optimal mineral extraction process from an environmental point of view. The biggest problem in conducting research activities in these areas is demonstrating to communities that research activities are of great common benefit and not of private interest. Here are strategies for awareness-raising work in mountain communities, prior to the execution of a research project. The study case was taken on the project to install a monitoring system over high danger Arhuaycocha glacier lake at Río Blanco-Santa Cruz Sub-basin, Ancash, Peru, where the Santa Cruz district is located on the alluvial path. Awarenessraising activities were carried out, identification of actors, analysis of the social situation and perspectives of the inhabitants for the project. It was concluded that all research activities must be carried out with a high degree of sense of belonging on the part of the communities, showing direct benefits, and reach agreements with local authorities. A key point was the inclusion of the residents in the project activities, making it transparent and making it clear that science activities are carried out within their community.En el Perú las comunidades localizadas a lo largo de la cordillera de los Andes a más de 3000 metros sobre el nivel del mar tienen un comportamiento altamente susceptible a cualquier tipo de actividad de investigación sobre las áreas de montañas, debido principalmente al mal manejo de las empresas mineras durante muchas décadas, sin un proceso de extracción mineral ecoeficiente u óptimo desde un punto de vista ambiental. El mayor problema que surge al buscar realizar actividades de investigación en dichas áreas consiste en demostrar a las comunidades que las actividades de investigación son de un gran beneficio común y no de intereses particulares. En este artículo se muestran estrategias de trabajos de sensibilización en comunidades de montaña, previos a la ejecución de un proyecto de investigación. Se tomó el caso de estudio el proyecto de instalación de un sistema de monitoreo de la laguna peligrosa de origen glaciar Arhuaycocha, en la subcuenca Río Blanco-Santa Cruz, Áncash, donde el distrito Santa Cruz se ubica en el camino aluviónico. Se realizaron actividades de sensibilización, identificación de actores, análisis situación social y de perspectivas de los pobladores para con el proyecto.Se concluyó que en toda actividad de índole de investigación se debe de realizar con un grado alto de sentimiento de pertenencia por parte de las comunidades, mostrar beneficios directos y lograr acuerdos con las autoridades locales. Un punto clave fue la inclusión de los pobladores en las actividades del proyecto, transparentando y dejando en claro la realización de actividades de ciencia dentro de su comunidad

Anti-PD-1 immunotherapy leads to tuberculosis reactivation via dysregulation of TNF-alpha

Previously, we developed a 3-dimensional cell culture model of human tuberculosis (TB) and demonstrated its potential to interrogate the host-pathogen interaction (Tezera et al., 2017a). Here, we use the model to investigate mechanisms whereby immune checkpoint therapy for cancer paradoxically activates TB infection. In patients, PD-1 is expressed in Mycobacterium tuberculosis (Mtb)-infected lung tissue but is absent in areas of immunopathology. In the microsphere model, PD-1 ligands are up-regulated by infection, and the PD-1/PD-L1 axis is further induced by hypoxia. Inhibition of PD-1 signalling increases Mtb growth, and augments cytokine secretion. TNF-a is responsible for accelerated Mtb growth, and TNF-a neutralisation reverses augmented Mtb growth caused by anti-PD-1 treatment. In human TB, pulmonary TNF-a immunoreactivity is increased and circulating PD-1 expression negatively correlates with sputum TNF-a concentrations. Together, our findings demonstrate that PD-1 regulates the immune response in TB, and inhibition of PD-1 accelerates Mtb growth via excessive TNF-a secretion.</p

Photon-pair generation in photonic crystal fibre with a 1.5 GHz modelocked VECSEL

Four-wave mixing (FWM) in optical fibre is a leading technique for generating high-quality photon pairs. We report the generation of photon pairs by spontaneous FWM in photonic crystal fibre pumped by a 1.5 GHz repetition-rate vertical-external-cavity surface-emitting laser (VECSEL). The photon pairs exhibit high count rates and a coincidence-to-accidental ratio of over 80. The VECSEL's high repetition-rate, high average power, tunability, and small footprint make this an attractive source for quantum key distribution and photonic quantum-state engineering.Comment: 17 Pages, 5 Figure