5,747 research outputs found

    Millimeter Spectral Line Mapping Observations Toward Four Massive Star Forming HII Regions

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    We present spectral line mapping observations toward four massive star-forming regions (Cepheus A, DR21S, S76E and G34.26+0.15), with the IRAM 30 meter telescope at 2 mm and 3 mm bands. Totally 396 spectral lines from 51 molecules, one helium recombination line, ten hydrogen recombination lines, and 16 unidentified lines were detected in these four sources. An emission line of nitrosyl cyanide (ONCN, 140,14_{0,14}-130,13_{0,13}) was detected in G34.26+0.15, as first detection in massive star-forming regions. We found that the cc-C3_{3}H2_{2} and NH2_{2}D show enhancement in shocked regions as suggested by evidences of SiO and/or SO emission. Column density and rotational temperature of CH3_{3}CN were estimated with the rotational diagram method for all four sources. Isotope abundance ratios of 12^{12}C/13^{13}C were derived using HC3_{3}N and its 13^{13}C isotopologue, which were around 40 in all four massive star-forming regions and slightly lower than the local interstellar value (\sim65). 14^{14}N/15^{15}N and 16^{16}O/18^{18}O abundance ratios in these sources were also derived using double isotopic method, which were slightly lower than that in local interstellar medium. Except for Cep A, 33^{33}S/34^{34}S ratio in the other three targets were derived, which were similar to that in the local interstellar medium. The column density ratios of N(DCN)/N(HCN) and N(DCO+^{+})/N(HCO+^{+}) in these sources were more than two orders of magnitude higher than the elemental [D]/[H] ratio, which is 1.5×\times105 ^{-5}. Our results show the later stage sources, G34.26+0.15 in particular, present more molecular species than earlier stage ones. Evidence of shock activity is seen in all stages studied.Comment: 32 pages, 11 figures, 8 tables, accepted for publication in MNRA

    Effects of Acupuncture on Th1, Th2 Cytokines in Rats of Implantation Failure

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    The aim is to explore the effect of acupuncture on Th1, Th2 cytokines in rats of implantation failure. Early pregnant rats were randomized into normal group (N), implantation failure group (M), acupuncture group (A), progestin group (H). The model was established with mifepristone. Samples of serum, endometrium were collected on Day 5, 6 and 8 of pregnancy. Compared with group M, the number of embryos was significantly higher in groups N, A and H; IL-1β, IL-2 protein in serum and endometrium were significantly lower in groups N, A and H, while IL-4, IL-10 were significantly higher in groups N, A and H; the endometrial IL-2, IL-4 mRNA were significantly lower in groups N, A and H, while IL-1β, IL-10 mRNA were significantly higher in groups N, A and H. Acupuncture could improve the poor receptive state of endometrium due to mifepristone by promoting Th2 cytokines secretion and inhibiting Th1 cytokines to improve blastocyst implantation

    Bis(benzoato-κ2 O,O′)(2,2′-bipyridine-κ2 N,N′)lead(II) benzoic acid monosolvate

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    The reaction of lead acetate, benzoic acid and 2,2′-bipyridine (bipy) in aqueous solution yielded the title complex, [Pb(C7H5O2)2(C10H8N2)]·C7H6O2. The asymmetric unit contains two independent complex mol­ecules as well as two independent benzoic acid solvent mol­ecules, one of which is disordered over two positions with almost equal occupancies [0.504 (5) and 0.496 (5)]. The two complex mol­ecules have similar configurations with the hexa­coordinated environment of the PbII atom formed by four carboxyl­ate O atoms of two chelate benzoate ligands and two N atoms of the bipy ligand. The Pb—O bonds involving one of the benzoate ligands are almost coplanar with Pb—N bonds to the bipy ligand [dihedral angles of 12.67 (11) and 14.73 (11)°] ; if the second benzoate ligand is treated as one coordination site, the overall coordination may be represented as a distorted pseudo-square pyramid. Weak inter­molecular Pb⋯O inter­actions [3.046 (3) and 3.359 (3) Å] link each of the complex mol­ecules into two symmetry-independent centrosymmetric dimers. Hydrogen bonds involving the carboxyl H atoms of solvent benzoic acid mol­ecules and metal-coordinated carboxyl­ate O atoms link complex mol­ecules and benzoic acid solvent mol­ecules into insular aggregates

    Second-order statistics analysis and comparison between arithmetic and geometric average fusion: Application to multi-sensor target tracking

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    Two fundamental approaches to information averaging are based on linear and logarithmic combination, yielding the arithmetic average (AA) and geometric average (GA) of the fusing data, respectively. In the context of multisensor target tracking, the two most common formats of data to be fused are random variables and probability density functions, namely v-fusion and f-fusion, respectively. In this work, we analyze and compare the second-order statistics (including variance and mean square error) of AA and GA in terms of both v-fusion and f-fusion. The case of weighted Gaussian mixtures representing multitarget densities in the presence of false alarms and missed detections (whose weight sums are not necessarily unit) is also considered, the result of which turns out to be significantly different from that of a single target. In addition to exact derivation, exemplifying analyses and illustrations are also provided.This work was supported in part by the Marie Skłodowska-Curie Individual Fellowship under Grant 709267, in part by Shaanxi Natural Fund under Grant 2018MJ6048, in part by the Northwestern Polytechnical University, and in part by Junta Castilla y León, Consejería de Educación and FEDER funds under project SA267P18

    (2,2′-Bipyridine-κ2 N,N′)bis­(4-methyl­benzoato-κ2 O,O′)lead(II)

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    In the title compound, [Pb(C8H7O2)2(C10H8N2)], the PbII ion is coordinated by two N atoms from one 2,2′-bipyridine ligand and four O atoms from two 4-methyl­benzoate anions in a distorted pseudo-square-pyramidal environment, considering one of the carboxyl­ate anions as an apical ligand. Pairs of complex mol­ecules related by inversion centers are organized into dimers via pairs of Pb⋯O inter­actions [3.185 (2) Å] and stacking interactions between 2,2′-bipyridine and 4-methyl­benzoate ligands, with a mean distance between their planes of 3.491 Å

    Landslide Surface Displacement Prediction Based on VSXC-LSTM Algorithm

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    Landslide is a natural disaster that can easily threaten local ecology, people's lives and property. In this paper, we conduct modelling research on real unidirectional surface displacement data of recent landslides in the research area and propose a time series prediction framework named VMD-SegSigmoid-XGBoost-ClusterLSTM (VSXC-LSTM) based on variational mode decomposition, which can predict the landslide surface displacement more accurately. The model performs well on the test set. Except for the random item subsequence that is hard to fit, the root mean square error (RMSE) and the mean absolute percentage error (MAPE) of the trend item subsequence and the periodic item subsequence are both less than 0.1, and the RMSE is as low as 0.006 for the periodic item prediction module based on XGBoost\footnote{Accepted in ICANN2023}

    A Robust Multi-Sensor PHD Filter Based on Multi-Sensor Measurement Clustering

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    [EN] This letter presents a novel multi-sensor probability hypothesis density (PHD) filter for multi-target tracking by means of multiple or even massive sensors that are linked by a fusion center or by a peer-to-peer network. As a challenge, we find there is little known about the statistical properties of the sensors in terms of their measurement noise, clutter, target detection probability, and even potential cross-correlation. Our approach converts the collection of the measurements of different sensors to a set of proxy and homologous measurements. These synthetic measurements overcome the problems of false and missing data and of unknown statistics, and facilitate linear PHD updating that amounts to the standard PHD filtering with no false and missing data. Simulation has demonstrated the advantages and limitations of our approach in comparison with the cutting-edge multi-sensor/distributed PHD filters

    Diaqua­(5-methyl­pyrazine-2-carboxyl­ato-κ2 N 1,O)iron(II)

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    In the neutral title complex, [Fe(C6H5N2O2)2(H2O)2], the coordination geometry aound the FeII atom, which lies on an inversion centre, is distorted octa­hedral comprising two N atoms and two O atoms from two 5-methyl­pyrazine-2-carboxyl­ate ligands, and two water mol­ecules. The crystal structure is stabilized by a network of O—H⋯O hydrogen bonds, resulting in a two-dimensional supra­molecular structure
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