Tentative detection of phosphine in IRC+10216

The J,K = 1,0-0,0 rotational transition of phosphine (PH3) at 267 GHz has been tentatively identified with a T_MB = 40 mK spectral line observed with the IRAM 30-m telescope in the C-star envelope IRC+10216. A radiative transfer model has been used to fit the observed line profile. The derived PH3 abundance relative to H2 is 6 x 10^(-9), although it may have a large uncertainty due to the lack of knowledge about the spatial distribution of this species. If our identification is correct, it implies that PH3 has a similar abundance to that reported for HCP in this source, and that these two molecules (HCP and PH3) together take up about 5 % of phosphorus in IRC+10216. The abundance of PH3, as that of other hydrides in this source, is not well explained by conventional gas phase LTE and non-LTE chemical models, and may imply formation on grain surfaces.Comment: 4 pages, 2 figures; accepted for publication in A&A Letter

Mononuclear Nitrogen/sulfur-ligated Cobalt(II) Methoxide Complexes: Structural, EPR, Paramagnetic 1H NMR, and Electrochemical Investigations

The first examples of mononuclear nitrogen/sulfur-ligated Co(II) alkoxide complexes, species of relevance to a reactive intermediate observed for Co(II)-substituted liver alcohol dehydrogenase, have been isolated and characterized by multiple methods including X-ray crystallography, EPR, paramagnetic 1H NMR, and cyclic voltammetry

On the formation of glycolaldehyde in dense molecular cores

Glycolaldehyde is a simple monosaccharide sugar linked to prebiotic chemistry. Recently, it was detected in a molecular core in the star-forming region G31.41+0.31 at a reasonably high abundance. We investigate the formation of glycolaldehyde at 10 K to determine whether it can form efficiently under typical dense core conditions. Using an astrochemical model, we test five different reaction mechanisms that have been proposed in the astrophysical literature, finding that a gas-phase formation route is unlikely. Of the grain-surface formation routes, only two are efficient enough at very low temperatures to produce sufficient glycolaldehyde to match the observational estimates, with the mechanism culminating in CH3OH + HCO being favored. However, when we consider the feasibility of these mechanisms from a reaction chemistry perspective, the second grain-surface route looks more promising, H3CO + HCO

Performance of crossbred cows under grazing supplemented with soybean oil.

This work aimed to evaluate effect of soybean oil supplementation on dairy production of crossbred dairy cows under grazing. Twenty ½ and ¾ Holstein x Gyr cows with average of 77 days of lactation and 19.8 kg of daily milk yield were used under grazing of palisade grass (Brachiaria brizantha cv. Marandu) managed by intermittent stocking. In a 2 x 2 crossover trial, cows were homogeneously distributed between two experimental groups: 1) Control (C) ? supplementation with concentrate ration without soybean oil; and 2) Soybean oil (SO) ? addition 3% of soybean oil in concentrate ration (dry matter basis). Inclusion of soybean oil did not affect daily milk yield (P>0.05) in relation to control group. However, considering cost of oil inclusion and only the milk yield, this feed strategy is not economically viabl

Laboratory and tentative interstellar detection of trans-methyl formate using the publicly available Green Bank Telescope PRIMOS survey

The rotational spectrum of the higher-energy trans conformational isomer of methyl formate has been assigned for the first time using several pulsed-jet Fourier transform microwave spectrometers in the 6-60 GHz frequency range. This species has also been sought toward the Sagittarius B2(N) molecular cloud using the publicly available PRIMOS survey from the Green Bank Telescope. We detect seven absorption features in the survey that coincide with laboratory transitions of trans-methyl formate, from which we derive a column density of 3.1 (+2.6, -1.2) \times 10^13 cm-2 and a rotational temperature of 7.6 \pm 1.5 K. This excitation temperature is significantly lower than that of the more stable cis conformer in the same source but is consistent with that of other complex molecular species recently detected in Sgr B2(N). The difference in the rotational temperatures of the two conformers suggests that they have different spatial distributions in this source. As the abundance of trans-methyl formate is far higher than would be expected if the cis and trans conformers are in thermodynamic equilibrium, processes that could preferentially form trans-methyl formate in this region are discussed. We also discuss measurements that could be performed to make this detection more certain. This manuscript demonstrates how publicly available broadband radio astronomical surveys of chemically rich molecular clouds can be used in conjunction with laboratory rotational spectroscopy to search for new molecules in the interstellar medium.Comment: 40 pages, 7 figures, 4 tables; accepted for publication in Ap

The importance of non-LTE models for the interpretation of observations of interstellar NO

Context. The ALMA and Herschel missions promise to deliver data of high spatial and spectral resolution at far-infrared and submillimeter wavelengths. Modeling these data will require the knowledge of accurate radiative and collisional rates for species of astrophysical interest. Aims. We calculate the rotational excitation rate coefficients of NO in collisions with He and check the validity of the LTE approach in interpreting observations of rotational lines of NO. Methods. State-to-state rate coefficients between the 360 lowest hyperfine levels of NO were calculated using the M(J) randomizing limit method for temperatures from 10 K to 350 K. We performed calculations of the excitation of NO using the new rate coefficients using a large velocity gradient (LVG) radiative transfer code. Results. The critical densities of the lines are found to be at greater than or similar to 10(15) cm(-3). The low dipole moment of NO ensures that the line emission is optically thin up to column densities of similar to 10(15) cm(-2). Lines in the ground (Omega = 1/2) state are readily detectable in typical conditions (N(NO) = 10(13) cm(-2); T = 10-30 K), whereas lines in the excited Omega = 3/2 state are observed only in warm (T > 50 K) regions with higher column densities (N(NO) = 10(14) cm(-2)). Line ratios of NO may well be used to constrain the ambient temperature and/or density. Conclusions. The new rate coefficients will help significantly in interpreting NO emission lines observed with current and future telescopes, and enable this molecule to become a powerful astrophysical tool

Comportamento em pastejo e temperatura interna de vacas lactantes Gir x Holandês suplementadas com óleo de soja.

Objetivou-se com esse trabalho avaliar o comportamento em pastejo e a temperatura interna de vacas lactantes Gir x Holandês suplementadas ou não com óleo de soja. Foram utilizadas oito vacas ½ e ¾ Holandês-Zebu multíparas, com média de 84 dias em lactação e de 19 kg/leite/dia, as quais foram mantidas em pastagem de capim-marandu (Brachiaria brizantha Stapf cv. Marandu)