2,967 research outputs found

    Empowering materials processing and performance from data and AI

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    Improved determination of the 1(0)-0(0) rotational frequency of NH3D+ from the high resolution spectrum of the v4 infrared band

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    The high resolution spectrum of the v4 band of NH3D+ has been measured by difference frequency IR laser spectroscopy in a multipass hollow cathode discharge cell. From the set of molecular constants obtained from the analysis of the spectrum, a value of 262817(6) MHz (3sigma) has been derived for the frequency of the 1(0)-0(0) rotational transition. This value supports the assignment to NH3D+ of lines at 262816.7 MHz recorded in radio astronomy observations in Orion-IRc2 and the cold prestellar core B1-bS.Comment: Accepted for publication in the Astrophysical Journal Letters 04 June 201

    New accurate measurement of 36ArH+ and 38ArH+ ro-vibrational transitions by high resolution IR absorption spectroscopy

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    The protonated Argon ion, 36^{36}ArH+^{+}, has been identified recently in the Crab Nebula (Barlow et al. 2013) from Herschel spectra. Given the atmospheric opacity at the frequency of its JJ=1-0 and JJ=2-1 rotational transitions (617.5 and 1234.6 GHz, respectively), and the current lack of appropriate space observatories after the recent end of the Herschel mission, future studies on this molecule will rely on mid-infrared observations. We report on accurate wavenumber measurements of 36^{36}ArH+^{+} and 38^{38}ArH+^{+} rotation-vibration transitions in the vv=1-0 band in the range 4.1-3.7 μ\mum (2450-2715 cm−1^{-1}). The wavenumbers of the RR(0) transitions of the vv=1-0 band are 2612.50135±\pm0.00033 and 2610.70177±\pm0.00042 cm−1^{-1} (±3σ\pm3\sigma) for 36^{36}ArH+^{+} and 38^{38}ArH+^{+}, respectively. The calculated opacity for a gas thermalized at a temperature of 100 K and a linewidth of 1 km.s−1^{-1} of the RR(0) line is 1.6×10−15×N1.6\times10^{-15}\times N(36^{36}ArH+^+). For column densities of 36^{36}ArH+^+ larger than 1×10131\times 10^{13} cm−2^{-2}, significant absorption by the RR(0) line can be expected against bright mid-IR sources

    Gonadotropin-inhibitory hormone and its receptors in teleosts: Physiological roles and mechanisms of actions

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    Gonadotropin-inhibitory hormone (GnIH) was the first reported hypothalamic neuropeptide inhibiting reproduction in vertebrates. Since its discovery in the quail brain, its orthologs have been identified in a variety of vertebrate species and even protochordates. Depending on the species, the GnIH precursor polypeptides comprise two, three or four mature peptides of the RFamide family. It has been well documented that GnIH inhibits reproduction at the brain-pituitary–gonadal levels and participates in metabolism, stress response, and social behaviors in birds and mammals. However, most studies in fish have mainly been focused on the physiological roles of GnIH in the control of reproduction and results obtained are in some cases conflicting, leaving aside its potential roles in the regulation of other functions. In this manuscript we summarize the information available in fish with respect to the structural diversity of GnIH peptides and functional roles of GnIH in reproduction and other physiological processes. We also highlight the molecular mechanisms of GnIH actions on target cells and possible interactions with other neuroendocrine factors

    Detection of the Ammonium Ion in Space

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    We report on the detection of a narrow feature at 262816.73 MHz towards Orion and the cold prestellar core B1-bS, that we attribute to the 1(0)-0(0) line of the deuterated Ammonium ion, NH3D+. The observations were performed with the IRAM 30m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved indicating a very low value for the electric quadrupolar coupling constant of Nitrogen which is expected for NH3D+ as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1(0)-0(0) transition of the Ammonium ion, 262817(6) MHz (3sigma), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is 1.1(0.2)e12 cm-2. Assuming a deuterium enhancement similar to that of NH2D, we derive N(NH4+) sim 2.6e13 cm-2, i.e., an abundance for Ammonium of a few 1e(-11).Comment: Accepted for publication in the Astrophysical Journal Letters 04 June 201

    The Effect of Using Exoskeleton of Blue Crab (Callinectes sapidus) as a Dietary Calcium Source on the Egg Characteristics of Layer Hens (Gallus gallus domesticus)

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    The study focuses on the ability to use the exoskeleton of blue crab as alternative calcium and carotenoid supplement for layer hens and its effects on egg characteristics. Three groups of eighty layer hens each were fed a base feed formulation following the standards of the University of the Philippines Los Baños. The feeds were base feed as negative control (NG), a base feed with natural egg yolk colorants (capsorubin and lutein) as positive control (PG), and a base feed with 1% ground blue crab exoskeletons, as experimental (EG). The feeding lasted four weeks before egg collection. The eggs were weighed for their albumen, yolk, shell, and egg weight. The egg yolk color was determined using a DSM Fan and a digital Chroma meter, and the shell thickness using digital calipers. Statistical treatment was done through Kruskal Wallis test using SPSS software. Results showed that eggs of EG had significantly heavier shells with a mean of 5.93±0.11g, compared to 5.83±0.08g of the NG and 5.55±0.08g of the PG. Eggshell thickness was not significantly different among the three groups. Egg yolk color was significantly different in PG with a mean DSM gradient value of 11.96±0.11, compared to 5.92±0.14 of the NG and 6.48±0.20 of EG. Ground blue crab exoskeleton as a calcium supplement may increase the weight of the eggshells but may not intensify the egg yolk color
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