scholarly journals Volatile Abundances, Extended Coma Sources, and Nucleus Ice Associations in Comet C/2014 Q2 (Lovejoy)

2022 ◽  
Vol 3 (1) ◽  
pp. 6
Author(s):  
Neil Dello Russo ◽  
Ronald J. Vervack ◽  
Hideyo Kawakita ◽  
Boncho P. Bonev ◽  
Michael A. DiSanti ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Infrared Spectra ◽  
Spatial Distributions ◽  
Rotational Period ◽  
Production Rates ◽  
Relative Abundances ◽  
Typical Range

Abstract High-resolution infrared spectra of comet C/2014 Q2 Lovejoy were acquired with NIRSPEC at the W. M. Keck Observatory on two post-perihelion dates (UT 2015 February 2 and 3). H2O was measured simultaneously with CO, CH3OH, H2CO, CH4, C2H6, C2H4, C2H2, HCN, and NH3 on both dates, and rotational temperatures, production rates, relative abundances, H2O ortho-to-para ratios, and spatial distributions in the coma were determined. The first detection of C2H4 in a comet from ground-based observations is reported. Abundances relative to H2O for all species were found to be in the typical range compared with values for other comets in the overall population to date. There is evidence of variability in rotational temperatures and production rates on timescales that are small compared with the rotational period of the comet. Spatial distributions of volatiles in the coma suggest complex outgassing behavior. CH3OH, HCN, C2H6, and CH4 spatial distributions in the coma are consistent with direct release from associated ices in the nucleus and are peaked in a more sunward direction compared with co-measured dust. H2O spatial profiles are clearly distinct from these other four species, likely due to a sizable coma contribution from icy grain sublimation. Spatial distributions for C2H2, H2CO, and NH3 suggest substantial contributions from extended coma sources, providing further evidence for distinct origins and associations for these species in comets. CO shows a different spatial distribution compared with other volatiles, consistent with jet activity from discrete nucleus ice sources.

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

High resolution infrared spectra of water vapor

1969 ◽  
Vol 29 (1-3) ◽  
pp. 312-347 ◽  
Author(s):  
Phillip E. Fraley ◽  
K. Narahari Rao ◽  
L.H. Jones
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Infrared Spectra

Radiofrequency, Microwave, Submillimeter-Wave, and High-Resolution Infrared Spectra of thev6= 1 Vibrational State of CDF3

1997 ◽  
Vol 182 (1) ◽  
pp. 34-49 ◽  
Author(s):  
H. Bürger ◽  
J. Cosléou ◽  
J. Demaison ◽  
C. Gerke ◽  
H. Harder ◽  
...  
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Vibrational State ◽  
Submillimeter Wave

Erratum: High resolution infrared spectra of the ν2 and 2ν1 bands of 14N16O2

1976 ◽  
Vol 54 (10) ◽  
pp. 1087-1087
Author(s):  
Aldée Cabana ◽  
Michel Laurin ◽  
Walter J. Lafferty ◽  
Robert L. Sams
Keyword(s):  
High Resolution ◽  
Infrared Spectra

High Resolution Infrared Spectra of the ν2 and 2ν1 Bands of 14N16O2

1975 ◽  
Vol 53 (19) ◽  
pp. 1902-1926 ◽  
Author(s):  
Aldée Cabana ◽  
Michel Laurin ◽  
Walter J. Lafferty ◽  
Robert L. Sams
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Ground State ◽  
Equilibrium Structure ◽  
Coriolis Interaction ◽  
Rotational Constants ◽  
Average Structures

The infrared spectra of two B type bands, ν2 and 2ν1, of 14N16O2 have been recorded under high resolution. Ground state combination differences from these bands have been combined with combination differences obtained in previous studies and eight pure rotational microwave transitions to yield improved ground state rotational constants. Upper state constants and band centers for the ν2 and 2ν1 bands are also reported. The 2ν1 band contains internal intensity anomalies believed to arise from a weak Coriolis interaction with the much stronger ν1 + ν3 band. Equilibrium rotational constants have been calculated. The equilibrium structure of the molecule is: rc = 1.1945 ± 0.0005 Å and Θc = 133.85 ± 0.10°. For the sake of comparison, effective, substitution, and average structures are also reported.

scholarly journals Effect of Droplet Size and Counterions on the Spatial Distribution of Ions

2019 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Spatial Distribution ◽  
Reaction Mechanisms ◽  
Charge Carriers ◽  
Transfer Reactions ◽  
Spatial Distributions ◽  
Hydronium Ions ◽  
Ionic Atmosphere ◽  
Droplet Sizes ◽  
Charge Transfer Reactions ◽  
First Time

Electrosprayed droplets have emerged as a new environment for accelerating chemical reactions by orders of magnitude relative to their bulk analogues. Nevertheless the reaction mechanisms are still unknown. Unraveling the ion spatial distribution is critical as to where charge transfer reactions are likely to take place and as to their effect on the ionic atmosphere of macroions. Here we investigate the ion spatial distributions in aqueous droplets with diameters in the range of 5 nm to 16 nm with and without counterions using molecular dynamics. The charge carriers are Na, Cl ions and model hydronium ions. For the first time droplet sizes that are accessible to experimental scrutiny are modeled atomistically. <br>

scholarly journals A new pan-European dataset for gridded daily average wind speed based on in-situ observations

2021 ◽  
Author(s):  
Jouke de Baar ◽  
Gerard van der Schrier ◽  
Irene Garcia-Marti ◽  
Else van den Besselaar
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Cross Validation ◽  
Data Sets ◽  
Optimal Prediction ◽  
Auxiliary Variables ◽  
Climate Data ◽  
Ensemble Spread ◽  
Wind Fields

&lt;p&gt;&lt;strong&gt;Objective&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The purpose of the European Copernicus Climate Change Service (C3S) is to support society by providing information about the past, present and future climate. For the service related to &lt;em&gt;in-situ&lt;/em&gt; observations, one of the objectives is to provide high-resolution (0.1x0.1 and 0.25x0.25 degrees) gridded wind speed fields. The gridded wind fields are based on ECA&amp;D daily average station observations for the period 1970-2020.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Research question&lt;/strong&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;We address the following research questions: [1] How efficiently can we provide the gridded wind fields as a statistically reliable ensemble, in order to represent the uncertainty of the gridding? [2] How efficiently can we exploit high-resolution geographical auxiliary variables (e.g. digital elevation model, terrain roughness) to augment the station data from a sparse network, in order to provide gridded wind fields with high-resolution local features?&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;In our analysis, we apply greedy forward selection linear regression (FSLR) to include the high-resolution effects of the auxiliary variables on monthly-mean data. These data provide a &amp;#8216;background&amp;#8217; for the daily estimates. We apply cross-validation to avoid FSLR over-fitting and use full-cycle bootstrapping to create FSLR ensemble members. Then, we apply Gaussian process regression (GPR) to regress the daily anomalies. We consider the effect of the spatial distribution of station locations on the GPR gridding uncertainty.&lt;/p&gt;&lt;p&gt;The goal of this work is to produce several decades of daily gridded wind fields, hence, computational efficiency is of utmost importance. We alleviate the computational cost of the FSLR and GPR analyses by incorporating greedy algorithms and sparse matrix algebra in the analyses.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Novelty&lt;/strong&gt;&amp;#160;&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;The gridded wind fields are calculated as a statistical ensemble of realizations. In the present analysis, the ensemble spread is based on uncertainties arising from the auxiliary variables as well as from the spatial distribution of stations.&lt;/p&gt;&lt;p&gt;Cross-validation is used to tune the GPR hyper parameters. Where conventional GPR hyperparameter tuning aims at an optimal prediction of the gridded mean, instead, we tune the GPR hyperparameters for optimal prediction of the gridded ensemble spread.&lt;/p&gt;&lt;p&gt;Building on our experience with providing similar gridded climate data sets, this set of gridded wind fields is a novel addition to the E-OBS climate data sets.&lt;/p&gt;

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