318 research outputs found
MCTK: a Multi-modal Conversational Troubleshooting Kit for supporting users in web applications
Conversational Interfaces for user assistance are becoming persuasive. Today, though, most chatbots are not integrated into the application in which they are placed, but only superimposed, with no communication between the conversational and the graphical interface. We propose Multi-modal Conversational Troubleshooting Kit (MCTK), a Python package to easily integrate a conversational agent for troubleshooting in web applications. MCTK is multi-modal: once the system recognizes the problem the user is encountering, the textual solution in the chat is coupled with visual hints in the GUI. On top of that, MCTK is easy to configure and offers separation of concerns: dialogue designers can work on the conversation without the necessity of modifying the code, and vice versa
Morphology, dynamics and plasma parameters of plumes and inter-plume regions in solar coronal holes
Coronal plumes, which extend from solar coronal holes (CH) into the high
corona and - possibly - into the solar wind (SW), can now continuously be
studied with modern telescopes and spectrometers on spacecraft, in addition to
investigations from the ground, in particular, during total eclipses. Despite
the large amount of data available on these prominent features and related
phenomena, many questions remained unanswered as to their generation and
relative contributions to the high-speed streams emanating from CHs. An
understanding of the processes of plume formation and evolution requires a
better knowledge of the physical conditions at the base of CHs, in plumes and
in the surrounding inter-plume regions (IPR). More specifically, information is
needed on the magnetic field configuration, the electron densities and
temperatures, effective ion temperatures, non-thermal motions, plume
cross-sections relative to the size of a CH, the plasma bulk speeds, as well as
any plume signatures in the SW. In spring 2007, the authors proposed a study on
"Structure and dynamics of coronal plumes and inter-plume regions in solar
coronal holes" to the International Space Science Institute (ISSI) in Bern to
clarify some of these aspects by considering relevant observations and the
extensive literature. This review summarizes the results and conclusions of the
study. Stereoscopic observations allowed us to include three-dimensional
reconstructions of plumes. Multi-instrument investigations carried out during
several campaigns led to progress in some areas, such as plasma densities,
temperatures, plume structure and the relation to other solar phenomena, but
not all questions could be answered concerning the details of plume generation
process(es) and interaction with the SW.Comment: To appear on: The Astronomy and Astrophysics Review. 72 pages, 30
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Comparing extrapolations of the coronal magnetic field structure at 2.5 solar radii with multi-viewpoint coronagraphic observations
The magnetic field shapes the structure of the solar corona but we still know
little about the interrelationships between the coronal magnetic field
configurations and the resulting quasi-stationary structures observed in
coronagraphic images (as streamers, plumes, coronal holes). One way to obtain
information on the large-scale structure of the coronal magnetic field is to
extrapolate it from photospheric data and compare the results with
coronagraphic images. Our aim is to verify if this comparison can be a fast
method to check systematically the reliability of the many methods available to
reconstruct the coronal magnetic field. Coronal fields are usually extrapolated
from photospheric measurements typically in a region close to the central
meridian on the solar disk and then compared with coronagraphic images at the
limbs, acquired at least 7 days before or after to account for solar rotation,
implicitly assuming that no significant changes occurred in the corona during
that period. In this work, we combine images from three coronagraphs
(SOHO/LASCO-C2 and the two STEREO/SECCHI-COR1) observing the Sun from different
viewing angles to build Carrington maps covering the entire corona to reduce
the effect of temporal evolution to ~ 5 days. We then compare the position of
the observed streamers in these Carrington maps with that of the neutral lines
obtained from four different magnetic field extrapolations, to evaluate the
performances of the latter in the solar corona. Our results show that the
location of coronal streamers can provide important indications to discriminate
between different magnetic field extrapolations.Comment: Accepted by A&A the 20th of May, 201
Development of Dietary-Based Toxicity Reference Values to Assess the Risk of Chlorophacinone to Non-Target Raptorial Birds
Regulatory changes in the use of some second-generation anticoagulant rodenticides in parts of North America may result in expanded use of first-generation anticoagulant rodenticides (FGARs). Recent toxicological studies with captive raptors have demonstrated that these species are considerably more sensitive to the FGAR diphacinone than traditional avian wildlife test species (mallard, bobwhite). We have now examined the toxicity of the FGAR chlorophacinone (CPN) to American kestrels fed rat tissue mechanically amended with CPN, or rat tissue containing biologically-incorporated CPN, for 7 days. Nominal CPN concentrations in these diets were 0.15, 0.75, and 1.5 ÎŒg/g food wet weight, and actual CPN concentration in diets were analytically verified as being close to target values. Food intake was consistent among groups, body weight fluctuated by less than 6%, exposure and adverse effects were generally dose-dependent, and there were no dramatic differences in toxicity between mechanically-amended and biologically-incorporated CPN diets. Using benchmark dose statistical methods, toxicity reference values at which clotting times were prolonged in 50% of the kestrels was estimated to be about 80 ÎŒg CPN consumed/kg body weight-day for prothrombin time and 40 ÎŒg CPN/kg body weight-day for Russellâs viper venom time. Based upon carcass CPN residues reported in rodents from field baiting studies, empirical measures of food consumption in kestrels, and dietary-based toxicity reference values derived from the 7-day exposure scenario, some free-ranging raptors consuming CPN-exposed prey might exhibit coagulopathy and hemorrhage. These sublethal responses associated with exposure to environmentally realistic concentrations of CPN could compromise survival of exposed birds
Toxicity reference values for chlorophacinone and their application for assessing anticoagulant rodenticide risk to raptors
Despite widespread use and benefit, there are
growing concerns regarding hazards of second-generation
anticoagulant rodenticides to non-target wildlife which
may result in expanded use of first-generation compounds,
including chlorophacinone (CPN). The toxicity of CPN
over a 7-day exposure period was investigated in American
kestrels (Falco sparverius) fed either rat tissue mechanically-
amended with CPN, tissue from rats fed Rozol bait
(biologically-incorporated CPN), or control diets (tissue
from untreated rats or commercial bird of prey diet)
ad libitum. Nominal CPN concentrations in the formulated
diets were 0.15, 0.75 and 1.5 ”g/g food wet weight, and
measured concentrations averaged 94 % of target values.
Kestrel food consumption was similar among groups and
body weight varied by less than 6 %. Overt signs of
intoxication, liver CPN residues, and changes in prothrombin
time (PT), Russellâs viper venom time (RVVT)
and hematocrit, were generally dose-dependent. Histological
evidence of hemorrhage was present at all CPN dose levels, and most frequently observed in pectoral muscle and heart. There were no apparent differences in toxicity
between mechanically-amended and biologically-incorporated
CPN diet formulations. Dietary-based toxicity reference
values at which clotting times were prolonged in
50 % of the kestrels were 79.2 ”g CPN consumed/kg body
weight-day for PT and 39.1 ”g/kg body weight-day for
RVVT. Based upon daily food consumption of kestrels and
previously reported CPN concentrations found in small
mammals following field baiting trials, these toxicity reference
values might be exceeded by free-ranging raptors
consuming such exposed prey. Tissue-based toxicity reference
values for coagulopathy in 50 % of exposed birds
were 0.107 ”g CPN/g liver wet weight for PT and
0.076 ”g/g liver for RVVT, and are below the range of
residue levels reported in raptor mortality incidents
attributed to CPN exposure. Sublethal responses associated
with exposure to environmentally realistic concentrations
of CPN could compromise survival of free-ranging raptors,
and should be considered in weighing the costs and benefits
of anticoagulant rodenticide use in pest control and eradication
programs
Bound To Shock: Protection from Lethal Endotoxemic Shock by a Novel, Nontoxic, Alkylpolyamine Lipopolysaccharide Sequestrant
Lipopolysaccharide (LPS), or endotoxin, a structural component of gram-negative bacterial outer membranes, plays a key role in the pathogenesis of septic shock, a syndrome of severe systemic inflammation which leads to multiple-system organ failure. Despite advances in antimicrobial chemotherapy, sepsis continues to be the commonest cause of death in the critically ill patient. This is attributable to the lack of therapeutic options that aim at limiting the exposure to the toxin and the prevention of subsequent downstream inflammatory processes. Polymyxin B (PMB), a peptide antibiotic, is a prototype small molecule that binds and neutralizes LPS toxicity. However, the antibiotic is too toxic for systemic use as an LPS sequestrant. Based on a nuclear magnetic resonance-derived model of polymyxin B-LPS complex, we had earlier identified the pharmacophore necessary for optimal recognition and neutralization of the toxin. Iterative cycles of pharmacophore-based ligand design and evaluation have yielded a synthetically easily accessible N1,mono-alkyl-mono-homologated spermine derivative, DS-96. We have found that DS-96 binds LPS and neutralizes its toxicity with a potency indistinguishable from that of PMB in a wide range of in vitro assays, affords complete protection in a murine model of LPS-induced lethality, and is apparently nontoxic in vertebrate animal models.This work was supported by NIH grant 1R01 AI50107
In-flight validation of Metis Visible-light Polarimeter Coronagraph on board Solar Orbiter
Context. The Metis coronagraph is one of the remote-sensing instruments of
the ESA/NASA Solar Orbiter mission. Metis is aimed at the study of the solar
atmosphere and solar wind by simultaneously acquiring images of the solar
corona at two different wavelengths; visible-light (VL) within a band ranging
from 580 nm to 640 nm, and in the HI Ly-alpha 121.6 +/- 10 nm ultraviolet (UV)
light. The visible-light channel includes a polarimeter with electro-optically
modulating Liquid Crystal Variable Retarders (LCVRs) to measure the linearly
polarized brightness of the K-corona to derive the electron density.
Aims. In this paper, we present the first in-flight validation results of the
Metis polarimetric channel together with a comparison to the on-ground
calibrations. It is the validation of the first use in deep space (with hard
radiation environment) of an electro-optical device: a liquid crystal-based
polarimeter.
Methods. We used the orientation of the K-corona's linear polarization vector
during the spacecraft roll maneuvers for the in-flight calibration.
Results. The first in-flight validation of the Metis coronagraph on-board
Solar Orbiter shows a good agreement with the on-ground measurements. It
confirms the expected visible-light channel polarimetric performance. A final
comparison between the first pB obtained by Metis with the polarized brightness
(pB) obtained by the space-based coronagraph LASCO and the ground-based
coronagraph KCor shows the consistency of the Metis calibrated results.Comment: 8 pages, 13 figures, 3 tables, pape
Toxicity reference values for chlorophacinone and their application for assessing anticoagulant rodenticide risk to raptors
Despite widespread use and benefit, there are
growing concerns regarding hazards of second-generation
anticoagulant rodenticides to non-target wildlife which
may result in expanded use of first-generation compounds,
including chlorophacinone (CPN). The toxicity of CPN
over a 7-day exposure period was investigated in American
kestrels (Falco sparverius) fed either rat tissue mechanically-
amended with CPN, tissue from rats fed Rozol bait
(biologically-incorporated CPN), or control diets (tissue
from untreated rats or commercial bird of prey diet)
ad libitum. Nominal CPN concentrations in the formulated
diets were 0.15, 0.75 and 1.5 ”g/g food wet weight, and
measured concentrations averaged 94 % of target values.
Kestrel food consumption was similar among groups and
body weight varied by less than 6 %. Overt signs of
intoxication, liver CPN residues, and changes in prothrombin
time (PT), Russellâs viper venom time (RVVT)
and hematocrit, were generally dose-dependent. Histological
evidence of hemorrhage was present at all CPN dose levels, and most frequently observed in pectoral muscle and heart. There were no apparent differences in toxicity
between mechanically-amended and biologically-incorporated
CPN diet formulations. Dietary-based toxicity reference
values at which clotting times were prolonged in
50 % of the kestrels were 79.2 ”g CPN consumed/kg body
weight-day for PT and 39.1 ”g/kg body weight-day for
RVVT. Based upon daily food consumption of kestrels and
previously reported CPN concentrations found in small
mammals following field baiting trials, these toxicity reference
values might be exceeded by free-ranging raptors
consuming such exposed prey. Tissue-based toxicity reference
values for coagulopathy in 50 % of exposed birds
were 0.107 ”g CPN/g liver wet weight for PT and
0.076 ”g/g liver for RVVT, and are below the range of
residue levels reported in raptor mortality incidents
attributed to CPN exposure. Sublethal responses associated
with exposure to environmentally realistic concentrations
of CPN could compromise survival of free-ranging raptors,
and should be considered in weighing the costs and benefits
of anticoagulant rodenticide use in pest control and eradication
programs
Diversity of a cytokinin dehydrogenase gene in wild and cultivated barley
The cytokinin dehydrogenase gene HvCKX2.1 is the regulatory target for the most abundant heterochromatic small RNAs in drought-stressed barley caryopses. We investigated the diversity of HvCKX2.1 in 228 barley landraces and 216 wild accessions and identified 14 haplotypes, five of these with ten or more members, coding for four different protein variants. The third largest haplotype was abundant in wild accessions (51 members), but absent from the landrace collection. Protein structure predictions indicated that the amino acid substitution specific to haplotype 3 could result in a change in the functional properties of the HvCKX2.1 protein. Haplotypes 1â3 have overlapping geographical distributions in the wild population, but the average rainfall amounts at the collection sites for haplotype 3 plants are significantly higher during November to February compared to the equivalent data for plants of haplotypes 1 and 2. We argue that the likelihood that haplotype 3 plants were excluded from landraces by sampling bias that occurred when the first wild barley plants were taken into cultivation is low, and that it is reasonable to suggest that plants with haplotype 3 are absent from the crop because these plants were less suited to the artificial conditions associated with cultivation. Although the cytokinin signalling pathway influences many aspects of plant development, the identified role of HvCKX2.1 in the drought response raises the possibility that the particular aspect of cultivation that mitigated against haplotype 3 relates in some way to water utilization. Our results therefore highlight the possibility that water utilization properties should be looked on as a possible component of the suite of physiological adaptations accompanying the domestication and subsequent evolution of cultivated barley
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