563 research outputs found

    Some studies of the reactions of amines with aldehydes and with aromatic nitro - compounds in acetonitrile

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    Kinetic and equilibrium studies of the reactions between three trinitroaromatic species, 1,3,5-trinitrobenzene, ethyl 2,4,6-trmitrophenyl ether and phenyl 2,4,6- trinitrophenyl ether and the ahphatic amines n-butylamine, pyrrolidine and piperidine, in acetonitrile were undertaken. It was found that the reactions between 1,3,5-trinitrobenzene and each amine were too fast to measure. However kinetic information was gamed from the decomposition of the c-adducts formed from1.3.5- trinitrobenzene and both pyrrolidine and piperidme. Both the 3-adduct and the 1-adduct are observed as intermediates m the reaction of the ethyl ether with each amine, though formation of the 3-adduct was too fast to measure by stopped flow spectrometry. Formation of the picramides is subject to general acid catalysis due to the poor leaving group ability of the ethoxide ion. Only the 3-adduct intermediate was observed in the formation of each picramide from the phenyl ether. The fact that the 1-adduct is not seen is attributed to the phenoxide ion being a weaker base and hence a much superior leaving group to the ethoxide ion. The equilibrium constants K(_c,3)Âș and K(_c,1)Âș are a factor of ca. 10(^4) smaller in acetonitrile than dimethyl sulphoxide. This is due to acetonitrile being inferior to dimethyl sulphoxide in its ability to solvate charged species. The value of k(AM) for reaction at an unsubstituted position approaches the diffusion controlled Unit of acetonitrile. The reactions of propanal, 2-chloroethanal, 2,2-dichloroethanal and 2,2,2- trichloroethanal (chloral) with ammonia and several primary amines were studied. Only the reactions of ammonia with propanal and 2-chloroethanal produced the corresponding 2,4,6-trisubstituted-l,3,5-hexahydrotriazme.Reactions of the aldehydes with primary ammes yield propylidene imines as relatively stable species. Trimerisation was not observed however the imine may undergo dimerisation together with elimination of amine. Kinetic and equilibrium studies are reported on the formation in acetonitrile of2.4.6- triethyl-l,3,5-hexahydrotriazine, (TEHT), from propanal and ammonia, and also the corresponding decomposition reaction. The equilibrium constant was found to decrease with increasing water content in the acetonitrile which can be attributed to stabilisation of ammonia by the water. Good correlation was achieved for values of the equilibrium constant calculated directly from absorbance measurements and from combination of rate constants obtained from the formation and decomposition reactions

    Minimum Information about a Neuroscience Investigation (MINI) Electrophysiology

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    This module represents the formalized opinion of the authors and the CARMEN consortium, which identifies the minimum information required to report the use of electrophysiology in a neuroscience study, for submission to the CARMEN system (www.carmen.org.uk).
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    HIFI observations of warm gas in DR21: Shock versus radiative heating

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    The molecular gas in the DR21 massive star formation region is known to be affected by the strong UV field from the central star cluster and by a fast outflow creating a bright shock. The relative contribution of both heating mechanisms is the matter of a long debate. By better sampling the excitation ladder of various tracers we provide a quantitative distinction between the different heating mechanisms. HIFI observations of mid-J transitions of CO and HCO+ isotopes allow us to bridge the gap in excitation energies between observations from the ground, characterizing the cooler gas, and existing ISO LWS spectra, constraining the properties of the hot gas. Comparing the detailed line profiles allows to identify the physical structure of the different components. In spite of the known shock-excitation of H2 and the clearly visible strong outflow, we find that the emission of all lines up to > 2 THz can be explained by purely radiative heating of the material. However, the new Herschel/HIFI observations reveal two types of excitation conditions. We find hot and dense clumps close to the central cluster, probably dynamically affected by the outflow, and a more widespread distribution of cooler, but nevertheless dense, molecular clumps.Comment: Accepted for publication by A&

    Measuring the Autistic Women's Experience (AWE)

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    We developed a Dutch questionnaire called the Autistic Women's Experience (AWE) and compared its psychometric properties to the Autism Spectrum Quotient (AQ). Whilst attenuated gender differences on the AQ have been widely replicated, this instrument may not fully capture the unique experience of autistic women. The AWE was co-developed with autistic women to include items that reflect autistic women's experience. We investigated the AWE (49 items) and compared it with the AQ (50 items) in Dutch autistic individuals ( N = 153, n = 85 women) and in the general population ( N = 489, n = 246 women) aged 16+. Both the AQ and AWE had excellent internal consistency and were highly and equally predictive of autism in both women and men. Whilst there was a gender difference on the AQ among non-autistic people (men &gt; women), there was no gender difference among autistic people, confirming all earlier studies. No gender differences were detected on the AWE overall scale, yet subtle gender differences were observed on the subscales. We conclude that the AQ is valid for both genders, but the AWE provides an additional useful perspective on the characteristics of autistic women. The AWE needs further validation in independent samples using techniques that allow for testing gender biases, as well as a confirmatory factor analysis in a larger sample. </p

    Herschel observations in the ultracompact HII region Mon R2: Water in dense Photon-dominated regions (PDRs)

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    Mon R2, at a distance of 830 pc, is the only ultracompact HII region (UC HII) where the photon-dominated region (PDR) between the ionized gas and the molecular cloud can be resolved with Herschel. HIFI observations of the abundant compounds 13CO, C18O, o-H2-18O, HCO+, CS, CH, and NH have been used to derive the physical and chemical conditions in the PDR, in particular the water abundance. The 13CO, C18O, o-H2-18O, HCO+ and CS observations are well described assuming that the emission is coming from a dense (n=5E6 cm-3, N(H2)>1E22 cm-2) layer of molecular gas around the UC HII. Based on our o-H2-18O observations, we estimate an o-H2O abundance of ~2E-8. This is the average ortho-water abundance in the PDR. Additional H2-18O and/or water lines are required to derive the water abundance profile. A lower density envelope (n~1E5 cm-3, N(H2)=2-5E22 cm-2) is responsible for the absorption in the NH 1_1-0_2 line. The emission of the CH ground state triplet is coming from both regions with a complex and self-absorbed profile in the main component. The radiative transfer modeling shows that the 13CO and HCO+ line profiles are consistent with an expansion of the molecular gas with a velocity law, v_e =0.5 x (r/Rout)^{-1} km/s, although the expansion velocity is poorly constrained by the observations presented here.Comment: 4 pages, 5 figure

    Strong CH+ J=1-0 emission and absorption in DR21

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    We report the first detection of the ground-state rotational transition of the methylidyne cation CH+ towards the massive star-forming region DR21 with the HIFI instrument onboard the Herschel satellite. The line profile exhibits a broad emission line, in addition to two deep and broad absorption features associated with the DR21 molecular ridge and foreground gas. These observations allow us to determine a CH+ J=1-0 line frequency of 835137 +/- 3 MHz, in good agreement with a recent experimental determination. We estimate the CH+ column density to be a few 1e13 cm^-2 in the gas seen in emission, and > 1e14 cm^-2 in the components responsible for the absorption, which is indicative of a high line of sight average abundance [CH+]/[H] > 1.2x10^-8. We show that the CH+ column densities agree well with the predictions of state-of-the-art C-shock models in dense UV-illuminated gas for the emission line, and with those of turbulent dissipation models in diffuse gas for the absorption lines.Comment: Accepted for publication in A&

    Gas morphology and energetics at the surface of PDRs: new insights with Herschel observations of NGC 7023

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    We investigate the physics and chemistry of the gas and dust in dense photon-dominated regions (PDRs), along with their dependence on the illuminating UV field. Using Herschel-HIFI observations, we study the gas energetics in NGC 7023 in relation to the morphology of this nebula. NGC 7023 is the prototype of a PDR illuminated by a B2V star and is one of the key targets of Herschel. Our approach consists in determining the energetics of the region by combining the information carried by the mid-IR spectrum (extinction by classical grains, emission from very small dust particles) with that of the main gas coolant lines. In this letter, we discuss more specifically the intensity and line profile of the 158 micron (1901 GHz) [CII] line measured by HIFI and provide information on the emitting gas. We show that both the [CII] emission and the mid-IR emission from polycyclic aromatic hydrocarbons (PAHs) arise from the regions located in the transition zone between atomic and molecular gas. Using the Meudon PDR code and a simple transfer model, we find good agreement between the calculated and observed [CII] intensities. HIFI observations of NGC 7023 provide the opportunity to constrain the energetics at the surface of PDRs. Future work will include analysis of the main coolant line [OI] and use of a new PDR model that includes PAH-related species.Comment: Accepted for publication in Astronomy and Astrophysics Letters (Herschel HIFI special issue), 5 pages, 5 figure

    Do adults with high functioning autism or Asperger Syndrome differ in empathy and emotion recognition?

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    The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (i) their self-reported ability to empathise with others and/or (ii) their ability to read mental states in others’ eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes’ Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions
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