2,691 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 cm1^{-1}). The wavenumbers of the RR(0) transitions of the vv=1-0 band are 2612.50135±\pm0.00033 and 2610.70177±\pm0.00042 cm1^{-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.s1^{-1} of the RR(0) line is 1.6×1015×N1.6\times10^{-15}\times N(36^{36}ArH+^+). For column densities of 36^{36}ArH+^+ larger than 1×10131\times 10^{13} cm2^{-2}, significant absorption by the RR(0) line can be expected against bright mid-IR sources

    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

    Atenção Primária à Saúde seletiva ou abrangente?

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    Relaciones entre las características estacionales y la productividad en una plantación de Salix nigra en el Delta Bonaerense del río Paraná (Argentina)

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    We studied the quality of forest site in a 6 years old commercial plantation of Salix nigra, located in the Paraná delta (Argentina), which shows a lower productivity than the average in the region. The objective of this study is to identify site components that determine this lower productivity. The environmental factors evaluated were the floristic community, the relief and the edafic factors and their relationship with the height of dominant trees and the site productivity. The lowest height growths were detected in high altitude sites or in plots with the former stratum of soil very wide (with clay-slimy texture), while the best height growths of trees were registered in low altitude sites with a very thin first soil horizon.Se estudió la calidad de estación de una plantación de Salix nigra, de seis años de edad, ubicada en el Delta del Paraná (Argentina), la cual registra una productividad menor a la promedio de la región. El objetivo del trabajo fue identificar los componentes de la estación determinantes de la baja productividad, a través del estudio de factores del ambiente tales como el suelo, la vegetación natural, el relieve del terreno y su relación con la altura de las plantas dominantes y la productividad. Los peores crecimientos se registraron en terrenos altos o en parcelas que presentaron la primera capa del suelo (de textura arcillo limosa) de mayor espesor, mientras que los mejores se registraron en los bajos con una primera capa de suelo de poco espesor
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