84 research outputs found
The molecular complexity of G34.3+0.2
Recent observations of the Orion-KL region have shown that the chemical distribution in the region is much more complex than originally thought. There are not just one nitrogen rich core and one diffuse oxygen rich region. But rather, at higher resolution, each of these regions breaks up into smaller more compact components associated with individual heating/energy sources. Additionally, one molecular species, acetone [\chem{(CH_3)_2CO}], has a distinctly different distribution from any other large molecular species. These results cannot be explained by current chemical models. In order to expand our understanding of the chemistry in complex regions like Orion-KL, we have observed four additional high mass star forming regions: W3, G34.3+0.2, W75N, and W51 e1/e2 at several spatial resolutions (1"" - 5""). The results of these multi-resolution observations (with an emphasis on G34.3), a comparison to the results from Orion-KL, and their implications for astrochemical models, will be presented.\\\\
\noindent{\footnotesize Friedel, D. N. \& Snyder, L. E. “High-Resolution =1 mm CARMA Observations of Large Molecules in Orion-KL.” Astrophysical Journal, 2008, 673, 962\\
Widicus Weaver, S. L. \& Friedel, D. N. “Complex Organic Molecules at High Spatial Resolution toward ORION-KL. I. Spatial Scales.” Astrophysical Journal Supplements, 2012, 201, 16\\
Friedel, D. N. \& Widicus Weaver, S. L. “Complex Organic Molecules at High Spatial Resolution toward ORION-KL. II. Kinematics.” Astrophysical Journal Supplements, 2012, 201, 17}Ope
Alma data mining toolkit
ADMIT (ALMA Data Mining Toolkit) is a Python based pipeline toolkit for the creation and
analysis of new science products from ALMA data.
ADMIT quickly provides users with a detailed overview of their
science products, for example: line identifications, line 'cutout' cubes, moment
maps, and emission type analysis (e.g., feature detection). Users
can download the small ADMIT pipeline product ( 20MB), analyze the
results, then fine-tune and re-run the ADMIT pipeline (or any part
thereof) on their own machines and interactively inspect the results.
ADMIT has both a web browser and command line interface available for
this purpose. By analyzing multiple data cubes simultaneously, data
mining between many astronomical sources and line transitions are possible. Users are also able to enhance the capabilities
of ADMIT by creating customized ADMIT tasks satisfying any special
processing needs. We will present some of the salient features of ADMIT and
example use cases
Admit: alma data mining toolkit
ADMIT (ALMA Data Mining Toolkit) is a toolkit for the creation and analysis of new science products from ALMA data. ADMIT is an ALMA Development Project written purely in Python. While specifically targeted for ALMA science and production use after the ALMA pipeline, it is designed to be generally applicable to radio-astronomical data. ADMIT quickly provides users with a detailed overview of their science products: line identifications, line 'cutout' cubes, moment maps, emission type analysis (e.g., feature detection), etc. Users can download the small ADMIT pipeline product (20MB), analyze the results, then fine-tune and re-run the ADMIT pipeline (or any part thereof) on their own machines and interactively inspect the results. ADMIT will have both a GUI and command line interface available for this purpose. By analyzing multiple data cubes simultaneously, data mining between many astronomical sources and line transitions will be possible. Users will also be able to enhance the capabilities of ADMIT by creating customized ADMIT tasks satisfying any special processing needs. Future implementations of ADMIT may include EVLA and other instruments
CARMA 1 CM LINE SURVEY OF ORION-KL
We have conducted the first 1 cm (27-35 GHz) line survey of the Orion-KL region by an array. With a primary beam of 4.5 arcminutes, the survey looks at a region 166,000 AU (0.56 pc) across. The data have a resolution of 6 arcseconds on the sky and 97.6 kHz(1.07-0.84 km/s) in frequency. This region of frequency space is much less crowded than at 3mm or 1mm frequencies and contains the fundamental transitions of several complex molecular species, allowing us to probe the largest extent of the molecular emission. We present the initial results, and comparison to 3mm results, from several species including, dimethyl ether [(CH)O], ethyl cyanide [CHCN], acetone [(CH)CO], SO, and SO
Complex Organic Molecules at High Spatial Resolution Toward Orion-KL I: Spatial Scales
Here we present high spatial resolution (<1 arcsecond) observations of
molecular emission in Orion-KL conducted using the Combined Array for Research
in Millimeter-Wave Astronomy (CARMA). This work was motivated by recent
millimeter continuum imaging studies of this region conducted at a similarly
high spatial resolution, which revealed that the bulk of the emission arises
from numerous compact sources, rather than the larger-scale extended structures
typically associated with the Orion Hot Core and Compact Ridge. Given that the
spatial extent of molecular emission greatly affects the determination of
molecular abundances, it is important to determine the true spatial scale for
complex molecules in this region. Additionally, it has recently been suggested
that the relative spatial distributions of complex molecules in a source might
give insight into the chemical mechanisms that drive complex chemistry in
star-forming regions. In order to begin to address these issues, this study
seeks to determine the spatial distributions of ethyl cyanide [C2H5CN],
dimethyl ether [(CH3)2O], methyl formate [HCOOCH3], formic acid [HCOOH],
acetone [(CH3)2CO], SiO, methanol [CH3OH], and methyl cyanide [CH3CN] in
Orion-KL at \lambda = 3 mm. We find that for all observed molecules, the
molecular emission arises from multiple components of the cloud that include a
range of spatial scales and physical conditions. Here we present the results of
these observations and discuss the implications for studies of complex
molecules in star-forming regions.Comment: Accepted for publication in the Astrophysical Journal Supplement;
Part 1 of a 2 paper series; 37 page
First Acetic Acid Survey with CARMA in Hot Molecular Cores
Acetic acid (CHCOOH) has been detected mainly in hot molecular cores
where the distribution between oxygen (O) and nitrogen (N) containing molecular
species is co-spatial within the telescope beam. Previous work has presumed
that similar cores with co-spatial O and N species may be an indicator for
detecting acetic acid. However, does this presumption hold as higher spatial
resolution observations become available of large O and N-containing molecules?
As the number of detected acetic acid sources is still low, more observations
are needed to support this postulate. In this paper, we report the first acetic
acid survey conducted with the Combined Array for Research in Millimeter-wave
Astronomy (CARMA) at 3 mm wavelengths towards G19.61-0.23, G29.96-0.02 and IRAS
16293-2422. We have successfully detected CHCOOH via two transitions toward
G19.61-0.23 and tentatively confirmed the detection toward IRAS 16293-2422 A.
The determined column density of CHCOOH is 2.0(1.0)
cm and the abundance ratio of CHCOOH to methyl formate (HCOOCH)
is 2.2(0.1) toward G19.61-0.23. Toward IRAS 16293 A, the
determined column density of CHCOOH is 1.6
cm and the abundance ratio of CHCOOH to methyl formate (HCOOCH)
is 1.0 both of which are consistent with abundance
ratios determined toward other hot cores. Finally, we model all known line
emission in our passband to determine physical conditions in the regions and
introduce a new metric to better reveal weak spectral features that are blended
with stronger lines or that may be near the 1-2 detection limit.Comment: 28 pages, 8 figures, accepted for publication in the ApJ; Revised
citation in session 2, references remove
Observational Results of a Multi-Telescope Campaign in Search of Interstellar Urea [(NH)CO]
In this paper, we present the results of an observational search for gas
phase urea [(NH)CO] observed towards the Sgr B2(N-LMH) region. We show
data covering urea transitions from 100 GHz to 250 GHz from five
different observational facilities: BIMA, CARMA, the NRAO 12 m telescope, the
IRAM 30 m telescope, and SEST. The results show that the features ascribed to
urea can be reproduced across the entire observed bandwidth and all facilities
by best fit column density, temperature, and source size parameters which vary
by less than a factor of 2 between observations merely by adjusting for
telescope-specific parameters. Interferometric observations show that the
emission arising from these transitions is cospatial and compact, consistent
with the derived source sizes and emission from a single species. Despite this
evidence, the spectral complexity, both of (NH)CO and of Sgr B2(N),
makes the definitive identification of this molecule challenging. We present
observational spectra, laboratory data, and models, and discuss our results in
the context of a possible molecular detection of urea.Comment: 38 pages, 9 Figures, accepted in the Astrophysical Journa
Los lenguajes controlados y la documentación técnica : mejorando la traducibilidad
Los lenguajes controlados pueden suponer una estrategia efectiva para mejorar los procesos de traducción, modificando el texto origen para que se adapte a una serie de reglas que mejoran su traducibilidad. El artículo analiza el concepto de lenguaje controlado y revisa las diferentes áreas de control y su tipología, para después realizar un breve repaso al origen y evolución de estos si stemas lingüísticos. A continuación explora qué papel representan los lenguajes controlados en el proceso de redacción y traducción de documentación técnica. Por último, se centra en la relación entre lenguajes controlados y traducción y, más en concreto, la traducción automática, haciendo especial hincapié en las reglas más efectivas para la mejora de la traducibilidad.Els llenguatges controlats poden suposar una estratègia efectiva per a millorar els processos de traducció, modificant el text origen perquè s'adapte a una sèrie de regles que milloren la seua traduïbilitat. L'article analitza el concepte de llenguatge controlat i revisa les diferents àrees de control i la seua tipologia, per a després realitzar un breu repàs a l'origen i evolució d'estos sistemes lingüístics. A continuació explora quin paper representen els llenguatges controlats en el procés de redacció i traducció de documentació tècnica. Finalment, es centra en la relació entre llenguatges controlats i traducció i, més concretament, traducció autom àtica, fent especial insistència en les regles més efectives per a la millora de la traduïbilitat.Controlled languages can be an effective strategy to improve translation processes, pre-editing the source text to conform to a set of rules to improve its translatability. This article analyses the concept of controlled language and reviews the different control areas and their typology. Further, it reviews the origin and evolution of these linguistic systems and explores the role controlled languages play in the process of writing and translating technical documentation. Finally, it focuses on the relationship between controlled language and translation and, more specifically, machine translation, with particular emphasis on the rules aimed at improving translatability
Expression-independent gene trap vectors for random and targeted mutagenesis in embryonic stem cells
Promoterless gene trap vectors have been widely used for high-efficiency gene targeting and random mutagenesis in embryonic stem (ES) cells. Unfortunately, such vectors are only effective for genes expressed in ES cells and this has prompted the development of expression-independent vectors. These polyadenylation (poly A) trap vectors employ a splice donor to capture an endogenous gene's polyadenylation sequence and provide transcript stability. However, the spectrum of mutations generated by these vectors appears largely restricted to the last intron of target loci due to nonsense-mediated mRNA decay (NMD) making them unsuitable for gene targeting applications. Here, we present novel poly A trap vectors that overcome the effect of NMD and also employ RNA instability sequences to improve splicing efficiency. The set of random insertions generated with these vectors show a significantly reduced insertional bias and the vectors can be targeted directly to a 5′ intron. We also show that this relative positional independence is linked to the human β-actin promoter and is most likely a result of its transcriptional activity in ES cells. Taken together our data indicate that these vectors are an effective tool for insertional mutagenesis that can be used for either gene trapping or gene targeting
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