770 research outputs found
A line confusion-limited millimeter survey of Orion KL. III. Sulfur oxide species
We present a study of the sulfur-bearing species detected in a line
confusion-limited survey towards Orion KL performed with the IRAM 30m telescope
in the range 80-281 GHz. The study is part of an analysis of the line survey
divided into families of molecules. Our aim is to derive accurate physical
conditions and molecular abundances in the different components of Orion KL
from observed SO and SO2 lines. First we assumed LTE conditions obtain
rotational temperatures. We then used a radiative transfer model, assuming
either LVG or LTE excitation to derive column densities of these molecules in
the different components of Orion KL. We have detected 68 lines of SO, 34SO,
33SO, and S18O and 653 lines of SO2, 34SO2, 33SO2, SO18O and SO2 v2=1. We
provide column densities for all of them and also upper limits for the column
densities of S17O, 36SO, 34S18O, SO17O and 34SO2 v2=1 and for several
undetected sulfur-bearing species. In addition, we present 2'x2' maps around
Orion IRc2 of SO2 transitions with energies from 19 to 131 K and also maps with
four transitions of SO, 34SO and 34SO2. We observe an elongation of the gas
along the NE-SW direction. An unexpected emission peak appears at 20.5 km/s in
most lines of SO and SO2. A study of the spatial distribution of this emission
feature shows that it is a new component ~5" in diameter, which lies ~4" west
of IRc2. We suggest the emission from this feature is related to shocks
associated to the BN object. The highest column densities for SO and SO2 are
found in the high-velocity plateau (a region dominated by shocks) and in the
hot core. These values are up to three orders of magnitude higher than the
results for the ridge components. We also find high column densities for their
isotopologues in both components. Therefore, we conclude that SO and SO2 are
good tracers, not only of regions affected by shocks, but also of regions with
warm dense gas.Comment: Paper (ref AA/2013/21285) accepted for publication by A&A. 52 Pages,
26 figures, 13 table
Referring Expressions and Communicative Success in Task-oriented Dialogues
This paper studies lexical and structural properties of coreference chains in task-oriented dialogue and investigates their relationship with perceived and factual com-municative success. In line with previous literature, our quantitative analysis shows that lexical entrainment is the most reliable predictor of task success, among the ones we compute. But also that there is a complex relationship between these factors – for example, neither high nor low, but rather intermediate levels of lexical alignment predict high perceived and factual success
A Saliency-based Clustering Framework for Identifying Aberrant Predictions
In machine learning, classification tasks serve as the cornerstone of a wide
range of real-world applications. Reliable, trustworthy classification is
particularly intricate in biomedical settings, where the ground truth is often
inherently uncertain and relies on high degrees of human expertise for
labeling. Traditional metrics such as precision and recall, while valuable, are
insufficient for capturing the nuances of these ambiguous scenarios. Here we
introduce the concept of aberrant predictions, emphasizing that the nature of
classification errors is as critical as their frequency. We propose a novel,
efficient training methodology aimed at both reducing the misclassification
rate and discerning aberrant predictions. Our framework demonstrates a
substantial improvement in model performance, achieving a 20\% increase in
precision. We apply this methodology to the less-explored domain of veterinary
radiology, where the stakes are high but have not been as extensively studied
compared to human medicine. By focusing on the identification and mitigation of
aberrant predictions, we enhance the utility and trustworthiness of machine
learning classifiers in high-stakes, real-world scenarios, including new
applications in the veterinary world
Development of A Dual-Fired Dryer for Augmentation of Fish Preservation
Food serves as one of the basic requirements for the well-being of every living being, but improper handling during post-harvesting stage to cater for the rainy day in the midst of insufficient energy source, is one of the factors responsible for food insecurity, especially in the developing countries. This study focused on the construction and evaluation of an adaptable dual-fired fish dryer. The dryer, designed to reduce moisture content of fish from 80% to 8% for proper product shelf life, has a rated drying capacity of 12 kg of fish per period of 4 hours per batch, while working on either electricity or natural gas as source of heat energy. Locally available materials were used in the construction of the device. The rig developed cost one hundred and forty-eight thousand eight hundred and twenty Naira (N148, 820.00). It was evaluated using salmon fish. The dryer is more efficient when electrically fired than when gas-fired and has the maximum drying and thermal efficiencies of 84.67 % and 92.93 % when operated at 85oC while the corresponding values when operated on gas are 36% and 62.65% respectively. Keywords: Food insecurity, Fish, dryer, Performance evaluation, Preservation, Incom
A combined IRAM and Herschel/HIFI study of cyano(di)acetylene in Orion KL: tentative detection of DC3N
We present a study of cyanoacetylene (HC3N) and cyanodiacetylene (HC5N) in
Orion KL, through observations from two line surveys performed with the IRAM
30m telescope and the HIFI instrument on board the Herschel telescope. The
frequency ranges covered are 80-280 GHz and 480-1906 GHz. We model the observed
lines of HC3N, HC5N, their isotopologues (including DC3N), and vibrational
modes, using a non-LTE radiative transfer code. To investigate the chemical
origin of HC3N and DC3N in Orion KL, we use a time-dependent chemical model. We
detect 40 lines of the ground state of HC3N and 68 lines of its 13C
isotopologues. We also detect 297 lines of six vibrational modes of this
molecule (nu_7, 2nu_7, 3nu_7, nu_6, nu_5, and nu_6+nu_7) and 35 rotational
lines of the ground state of HC5N. We report the first tentative detection of
DC3N in a giant molecular cloud with a DC3N/HC3N abundance ratio of 0.015. We
provide column densities and isotopic and molecular abundances. We also perform
a 2x2" map around Orion IRc2 and we present maps of HC3N lines and maps of
lines of the HC3N vibrational modes nu_6 and nu_7. In addition, a comparison of
our results for HC3N with those in other clouds allows us to derive
correlations between the column density, the FWHM, the mass, and the luminosity
of the clouds. The high column densities of HC3N obtained in the hot core, make
this molecule an excellent tracer of hot and dense gas. In addition, the large
frequency range covered reveals the need to consider a temperature and density
gradient in the hot core in order to obtain better line fits. The high D/H
ratio (comparable to that obtained in cold clouds) that we derive suggests a
deuterium enrichment. Our chemical models indicate that the possible deuterated
HC3N present in Orion KL is formed during the gas-phase. This fact provides new
hints concerning the processes leading to deuteration.Comment: 50 pages, 33 figures, 13 tables. Accepted for publication in A&
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Spontaneous expression classification in the encrypted domain
To date, most facial expression analysis have been based on posed image databases and is carried out without being able to protect the identity of the subjects whose expressions are being recognised. In this paper, we propose and implement a system for classifying facial expressions of images in the encrypted domain based on a Paillier cryptosystem implementation of Fisher Linear Discriminant Analysis and k-nearest neighbour (FLDA + kNN). We present results of experiments carried out on a recently developed natural visible and infrared facial expression (NVIE) database of spontaneous images. To the best of our knowledge, this is the first system that will allow the recog-nition of encrypted spontaneous facial expressions by a remote server on behalf of a client
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