2,377 research outputs found

    A high resolution study of complex organic molecules in hot cores

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    We present the results of a line identification analysis using data from the IRAM Plateau de Bure Inferferometer, focusing on six massive star-forming hot cores: G31.41+0.31, G29.96-0.02, G19.61-0.23, G10.62-0.38, G24.78+0.08A1 and G24.78+0.08A2. We identify several transitions of vibrationally excited methyl formate (HCOOCH3_3) for the first time in these objects as well as transitions of other complex molecules, including ethyl cyanide (C2_2H5_5CN), and isocyanic acid (HNCO). We also postulate a detection of one transition of glycolaldehyde (CH2_2(OH)CHO) in two new hot cores. We find G29.96-0.02, G19.61-0.23, G24.78+0.08A1 and 24.78+0.08A2 to be chemically very similar. G31.41+0.31, however, is chemically different: it manifests a larger chemical inventory and has significantly larger column densities. We suggest that it may represent a different evolutionary stage to the other hot cores in the sample, or it may surround a star with a higher mass. We derive column densities for methyl formate in G31.41+0.31, using the rotation diagram method, of ×\times1017^{17} cm−2^{-2} and a Trot_{rot} of ∼\sim170 K. For G29.96-0.02, G24.78+0.08A1 and G24.78+0.08A2, glycolaldehyde, methyl formate and methyl cyanide all seem to trace the same material and peak at roughly the same position towards the dust emission peak. For G31.41+0.31, however, glycolaldehyde shows a different distribution to methyl formate and methyl cyanide and seems to trace the densest, most compact inner part of hot cores.Comment: Accepted to MNRA

    Le relazioni sino-russe e il caso dell'Organizzazione per la cooperazione di Shangai

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    In uno scenario internazionale in cui le risorse di potere a disposizione dei vari attori sono in via di definizione e dove le dinamiche economiche paiono prevalere nel ridisegnare nuovi scenari ed equilibri, sia la Russia che la Cina si sono affermate come potenze centrali. La Cina, seppure contagiata dalla crisi ha saputo reagire e tornare a crescere in maniera più consistente e più celermente dei paesi del G-8 o degli altri BRIC e si consolida come la terza più grande economia del mondo

    Winds as the origin of radio emission in z=2.5z=2.5 radio-quiet extremely red quasars

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    Most active galactic nuclei (AGNs) are radio-quiet, and the origin of their radio emission is not well-understood. One hypothesis is that this radio emission is a by-product of quasar-driven winds. In this paper, we present the radio properties of 108 extremely red quasars (ERQs) at z=2−4z=2-4. ERQs are among the most luminous quasars (Lbol∼1047−48L_{bol} \sim 10^{47-48} erg/s) in the Universe, with signatures of extreme (≫1000\gg 1000 km/s) outflows in their [OIII]λ\lambda5007 \AA\ emission, making them the best subjects to seek the connection between radio and outflow activity. All ERQs but one are unresolved in the radio on ∼10\sim 10 kpc scales, and the median radio luminosity of ERQs is νLν[6 GHz]=1041.0\nu L_\nu [{\rm 6\,GHz}] = 10^{41.0} erg/s, in the radio-quiet regime, but one to two orders of magnitude higher than that of other quasar samples. The radio spectra are steep, with a mean spectral index ⟨α⟩=−1.0\langle \alpha \rangle = -1.0. In addition, ERQs neatly follow the extrapolation of the low-redshift correlation between radio luminosity and the velocity dispersion of [OIII]-emitting ionized gas. Uncollimated winds, with a power of one per cent of the bolometric luminosity, can account for all these observations. Such winds would interact with and shock the gas around the quasar and in the host galaxy, resulting in acceleration of relativistic particles and the consequent synchrotron emission observed in the radio. Our observations support the picture in which ERQs are signposts of extremely powerful episodes of quasar feedback, and quasar-driven winds as a contributor of the radio emission in the intermediate regime of radio luminosity νLν=1039−1042\nu L_\nu = 10^{39}-10^{42} erg/s.Comment: accepted by MNRA

    Direct Oral Anticoagulants and Their Use in Treatment and Secondary Prevention of Acute Symptomatic Venous Thromboembolism.

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    Direct oral anticoagulants (DOACs) have been compared with standard therapy in large phase III studies to assess their safety and efficacy in the treatment of deep vein thrombosis and/or pulmonary embolism and in the secondary prevention of recurrent venous thromboembolism. Although the mean population age and the gross inclusion and exclusion criteria were similar across these studies, they differed in other aspects such as overall study design and acute treatment strategies. The 4 DOACs examined in phase III trials (apixaban, edoxaban, rivaroxaban, and dabigatran) showed noninferiority compared with standard therapy for the treatment of deep vein thrombosis and/or pulmonary embolism and for the prevention of recurrent venous thromboembolism. Furthermore, these DOACs exhibited a similar safety profile to standard therapy, with the risk of major bleeding significantly reduced in some of these studies. Rivaroxaban and apixaban were tested as a single-drug approach, whereas in the dabigatran and edoxaban studies, initial bridging with parenteral agents was employed. The purpose of this review is to compare the phase III studies of DOACs in this indication, to highlight the differences, and to discuss a series of clinically relevant issues, including the management of key patient subgroups (eg, fragile patients, those with cancer or renal impairment), extended treatment, use of comedications, heparin pretreatment versus a single-drug approach, and the bleeding profiles of the DOACs

    Percolation transition and distribution of connected components in generalized random network ensembles

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    In this work, we study the percolation transition and large deviation properties of generalized canonical network ensembles. This new type of random networks might have a very rich complex structure, including high heterogeneous degree sequences, non-trivial community structure or specific spatial dependence of the link probability for networks embedded in a metric space. We find the cluster distribution of the networks in these ensembles by mapping the problem to a fully connected Potts model with heterogeneous couplings. We show that the nature of the Potts model phase transition, linked to the birth of a giant component, has a crossover from second to first order when the number of critical colors qc=2q_c = 2 in all the networks under study. These results shed light on the properties of dynamical processes defined on these network ensembles.Comment: 27 pages, 15 figure

    Non-local density correlations as signal of Hawking radiation in BEC acoustic black holes

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    We have used the analogy between gravitational systems and non-homogeneous fluid flows to calculate the density-density correlation function of an atomic Bose-Einstein condensate in the presence of an acoustic black hole. The emission of correlated pairs of phonons by Hawking-like process results into a peculiar long-range density correlation. Quantitative estimations of the effect are provided for realistic experimental configurations.Comment: Strongly revised version. 5 pages, 3 eps figure

    Discovery of a New Class of 1-(4-Sulfamoylbenzoyl)piperidine-4-carboxamides as Human Carbonic Anhydrase Inhibitors

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    A series of 1-(4-sulfamoylbenzoyl)piperidine-4-carboxamides deriving from substituted piperazines/benzylamines was designed, synthesized, and tested on human carbonic anhydrase (hCA). The inhibitory activity of the new sulfonamides was analyzed using acetazolamide (AAZ) as a standard inhibitor against hCA I, II, IX, and XII. Several sulfonamides showed both inhibitory activity at low nanomolar concentrations and selectivity against the cytosolic hCA II isoform, and the same trend was observed on the tumor-associated hCA IX and XII. The benzenesulfonamido carboxamides 11 and 15 were the most potent of the piperazino- and benzylamino-based series, respectively. Docking and molecular dynamics studies related the high selectivity of compound 11 toward the tumor-associated hCA isoforms to its capability to participate in favorable interactions within hCA IX and hCA XII active sites, whereas no such interactions were detected within both hCA I and hCA II isoforms

    Detection of solar-like oscillations in the G5 subgiant mu-Herculis

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    A clear detection of excess of power, providing a substantial evidence for solar-like oscillations in the G5 subgiant \muher{}, is presented. This star was observed over seven nights with the SARG echelle spectrograph operating with the 3.6-m Italian TNG Telescope, using an iodine absorption cell as a velocity reference. A clear excess of power centered at 1.2 mHz, with peak amplitudes of about 0.9 \ms in the amplitude spectrum is present. Fitting the asymptotic relation to the power spectrum, a mode identification for the ℓ=0,1,2,3\ell=0,1,2,3 modes in the frequency range 900-1600 \muHz is derived. The most likely value for the large separation turns out to be 56.5 \muHz, consistent with theoretical expectations. The mean amplitude per mode (l=0,1l=0,1) at peak power results to be 0.63ms−10.63 \rm m s^{-1}, almost three times larger than the solar one.Comment: 8 pages, 6 figures, ApJ to appea
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