HDO infrared detection sensitivity and D/H isotopic exchange in amorphous and crystalline ICE

6 p. : gráf.The sensitivity of the OD stretching band as a probe to detect HDO in astrophysical ice is discussed based on IR laboratory spectra of HDO molecules embedded in H2O ice. This band is extremely broad and tends to disappear into the absorption continuum of H2O for low-temperature amorphous samples. Detectable HDO/H2O ratios with this technique may range from a few percent for amorphous samples to a few per thousand in crystalline ice. These relatively high upper limits and the appreciable dependence of the band shape on temperature, which would complicate the interpretation of data from many lines of sight, decisively limit the usefulness of the technique for HDO detection in astronomical observations. The process of isotopic H/D exchange in mixed ice of H2O/D2O is also studied through the evolution of the OD band in IR spectra. Isotopic exchange starts at ∼120 K and is greatly accelerated at 150 K, as crystallization proceeds in the ice. Annealed amorphous samples prove to be more favorable for isotope exchange than samples directly formed in crystalline phase. The annealing process seems to favor a polycrystalline ice morphology with a higher defect activity. These morphology differences can be of relevance for deuterium fractionation in astronomical . © 2011 The American Astronomical Society.Funded by the MCINN of Spain under grants FIS2007-61686 and FIS2010-16455; “Ramon y Cajal” programPeer reviewe

How do neighboring peer companies influence SMEs’ financial behavior?

Recent research into corporate finances has found that the financial decisions of peer companies are related. Companies tend to “kept an eye” on the decisions of other peer companies, among other things, trying to overcome the limitations caused by the lack of information. This paper further examines these interactions including geographical proximity among companies. With this aim, we use a heterogeneous Partial Adjustment Model on a sample of 12, 444 small and medium Spanish manufacturing industrial companies. We find strong nonlinearities in the adjustment processes of liquidity, indebtedness and profitability ratios associated with basic characteristics of the companies such as size, technology, age or financial imbalances. Our results indicate that the influence of the environment on the financial behavior of each company, and its responsiveness, vary in function of neighbor firms’ characteristics

Inherent and learnt abilities for relative pitch in the vibrotactile domain using the fingertip

This paper reports experimental results concerning relative pitch discrimination. This is defined as the ability to distinguish one musical note as being higher or lower than another. Seventeen participants with normal hearing undertook a pitch discrimination experiment using the fingertip over a 16 session training period with a full baseline test before and after the training sessions. Two sinusoidal tones were presented, each of Is duration separated by a Is gap. A total of 24 tones were chosen to cover 12 intervals ranging from a semi-tone to an octave over the frequency range C3 to B4. The results show a high success rate for relative pitch discrimination with and without training. For intervals of 4 to 12 semitones, the success rates were >70% with or without the 16 training sessions. As a result of training, a significant improvement was found for individual intervals between 9 and 12 semitones when comparing the number of correct responses between pre-training and post-training tests. Comparison of pre- and post-training tests also showed an appreciable and significant improvement for the whole group of 12 intervals. In addition, reaction times to identify relative pitch tended to decrease over the training period

High energy electron irradiation of interstellar carbonaceous dust analogs: Cosmic ray effects on the carriers of the 3.4 μm absorption band

9 págs; 5 figs.; 6 tabs.The effects of cosmic rays on the carriers of the interstellar 3.4 μm absorption band have been investigated in the laboratory. This band is attributed to stretching vibrations of CH3 and CH2 in carbonaceous dust. It is widely observed in the diffuse interstellar medium, but disappears in dense clouds. Destruction of CH3 and CH2 by cosmic rays could become relevant in dense clouds, shielded from the external ultraviolet field. For the simulations, cules, formed by the recombination of H atoms liberated through CH bond breaking, diffuse out of the sample. The CH bond destruction rates derived from the present experiments are in good accordance with those from previous ion irradiation experiments of HAC. The experimental simplicity of electron the 3.4 μm band carriers lie in the 108 yr range and cannot account for the disappearance of this band in dense clouds, which have characteristic lifetimes of 3×107 yr. The results invite a more detailed investigation of the mechanisms of CH bond formation and breaking in the intermediate region between diffuse and dense clouds.This work has been funded by the MINECO of Spain under grant FIS2013-48087-C2-1P, by the MICINN of Spain under grant CDS2009-00038, and by the European project ERC-2013-Syg 610256. G.M. acknowledges MINECO PhD grant BES-2014-069355.Peer reviewe

Proteins with an Euonymus lectin-like domain are ubiquitous in Embryophyta

<p>Abstract</p> <p>Background</p> <p>Cloning of the <it>Euonymus </it>lectin led to the discovery of a novel domain that also occurs in some stress-induced plant proteins. The distribution and the diversity of proteins with an <it>Euonymus </it>lectin (EUL) domain were investigated using detailed analysis of sequences in publicly accessible genome and transcriptome databases.</p> <p>Results</p> <p>Comprehensive in silico analyses indicate that the recently identified <it>Euonymus europaeus </it>lectin domain represents a conserved structural unit of a novel family of putative carbohydrate-binding proteins, which will further be referred to as the <it>Euonymus </it>lectin (EUL) family. The EUL domain is widespread among plants. Analysis of retrieved sequences revealed that some sequences consist of a single EUL domain linked to an unrelated N-terminal domain whereas others comprise two in tandem arrayed EUL domains. A new classification system for these lectins is proposed based on the overall domain architecture. Evolutionary relationships among the sequences with EUL domains are discussed.</p> <p>Conclusion</p> <p>The identification of the EUL family provides the first evidence for the occurrence in terrestrial plants of a highly conserved plant specific domain. The widespread distribution of the EUL domain strikingly contrasts the more limited or even narrow distribution of most other lectin domains found in plants. The apparent omnipresence of the EUL domain is indicative for a universal role of this lectin domain in plants. Although there is unambiguous evidence that several EUL domains possess carbohydrate-binding activity further research is required to corroborate the carbohydrate-binding properties of different members of the EUL family.</p

Solid L-α-alanine: Spectroscopic properties and theoretical calculations

A spectroscopic study of L-α-alanine in different environments is presented, with special emphasis on the neutral to zwitterion transformation of this amino acid. Spectra of room temperature solids as deposited from the vapour and in KBr pellets are compared and discussed revealing some discrepancies. An assignment is proposed based on theoretical calculations of the solid structure. Vapour deposits at 25K are prepared both of pure alanine and of mixtures with polar (H 2O) and non-polar (CO 2, CH 4) components. The spectra of the solids contain IR bands which can be individually assigned to the neutral and to the zwitterion, and whose relative intensity variation can be used to follow the neutral to zwitterion transformation. The assignment of the spectrum of the neutral species is proposed, again with help from theoretical calculations of the single neutral molecule. The neutral/zwitterion ratio in deposits at 25K varies between ~60% for pure alanine and H 2O mixtures and ~90% for non-polar matrices. This ratio drops when the solid is heated until the ionic species only remains at 200K. The conversion process depends on the environment surrounding the alanine molecules. © 2012 Elsevier Ltd.funding from the Spanish Ministry of Science and Innovation, ProjectFIS2010-16455. financial support from Ministerio de Ciencia e Innovación, “Ramón y Cajal” programme and CSIC, JAE-Doc Programme, Sabbatical ProjectPR2010-0012.Peer Reviewe

Structure and infrared spectra of hydrocarbon interstellar dust analogs

9 págs.; 6 figs.; 5 tabs.A theoretical study of the structure and mid infrared (IR) spectra of interstellar hydrocarbon dust analogs is presented, based on DFT calculations of amorphous solids. The basic molecular structures for these solids are taken from two competing literature models. The first model considers small aromatic units linked by aliphatic chains. The second one assumes a polyaromatic core with hydrogen and methyl substituents at the edges. The calculated spectra are in reasonably good agreement with those of aliphatic-rich and graphitic-rich samples of hydrogenated amorphous carbon (HAC) generated in our laboratory. The theoretical analysis allows the assignment of the main vibrations in the HAC spectra and shows that there is a large degree of mode mixing. The calculated spectra show a marked dependence on the density of the model solids, which evinces the strong influence of the environment on the strengths of the vibrational modes. The present results indicate that the current procedure of estimating the hydrogen and graphitic content of HAC samples through the decomposition of IR features into vibrational modes of individual functional groups is problematic owing to the mentioned mode mixing and to the difficulty of assigning reliable and unique band strengths to the various molecular vibrations. Current band strengths from the literature might overestimate polyaromatic structures. Comparison with astronomical observations suggests that the average structure of carbonaceous dust in the diffuse interstellar medium lies probably in between those of the two models considered, though closer to the more aliphatic structure. ©the Owner Societies 2017This work has been funded by the MINECO of Spain under grant FIS2013-48087-C2-1P, and AYA2015-71975-REDT, by the MICINN of Spain under grant CDS2009-00038, and by the European project ERC-2013-SyG, Grant Agreement 610256 ‘‘NANOCOSMOS’’. G. M acknowledges MINECO PhD grant BES-2014-069355.Peer reviewe

Plasma generation and processing of interstellar carbonaceous dust analogs

ICPIG (2017) ; Presentación de 32 diapositivas ; Estoril, Lisbon, 9 to 14 July 2017 ; Invited Lecture to XXXIII ICPIG ; http://icpig2017.tecnico.ulisboa.pt/Different samples of plasma deposited amorphous hydrogenated carbon (HAC or a-C:H) are used as analogs of carbonaceous dust in the diffuse interstellar (IS) medium. Comparison of measured and theoretically calculated spectra suggests that IS dust grains are likely made of small aromatic islands linked by aliphatic chains. Irradiation of the HAC deposits with 5 keV electrons shows that the effects of cosmic rays on the aliphatic dust component, characterized by an absorption band at 3.4 m, are small and cannot explain the disappearance of this band in dense interstellar clouds.N