461 research outputs found

    A gas-rich AGN near the centre of a galaxy cluster at z ~ 1.4

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    The formation of the first virialized structures in overdensities dates back to ~9 Gyr ago, i.e. in the redshift range z ~ 1.4 - 1.6. Some models of structure formation predict that the star formation activity in clusters was high at that epoch, implying large reservoirs of cold molecular gas. Aiming at finding a trace of this expected high molecular gas content in primeval clusters, we searched for the 12CO(2-1) line emission in the most luminous active galactic nucleus (AGN) of the cluster around the radio galaxy 7C 1756+6520 at z ~ 1.4, one of the farthest spectroscopic confirmed clusters. This AGN, called AGN.1317, is located in the neighbourhood of the central radio galaxy at a projected distance of ~780 kpc. The IRAM Plateau de Bure Interferometer was used to investigate the molecular gas quantity in AGN.1317, observing the 12CO(2-1) emission line. We detect CO emission in an AGN belonging to a galaxy cluster at z ~ 1.4. We measured a molecular gas mass of 1.1 x 10^10 Msun, comparable to that found in submillimeter galaxies. In optical images, AGN.1317 does not seem to be part of a galaxy interaction or merger.We also derived the nearly instantaneous star formation rate (SFR) from Halpha flux obtaining a SFR ~65 Msun/yr. This suggests that AGN.1317 is actively forming stars and will exhaust its reservoir of cold gas in ~0.2-1.0 Gyr.Comment: 5 pages, 3 figures, accepted for publication in Astronomy & Astrophysic

    Decoherence times of universal two-qubit gates in the presence of broad-band noise

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    The controlled generation of entangled states of two quantum bits is a fundamental step toward the implementation of a quantum information processor. In nano-devices this operation is counteracted by the solid-state environment, characterized by a broadband and non-monotonic power spectrum, often 1/f at low frequencies. For single-qubit gates, incoherent processes due to fluctuations acting on different time scales result in peculiar short- and long-time behavior. Markovian noise gives rise to exponential decay with relaxation and decoherence times, T1 and T2, simply related to the symmetry of the qubit-environment coupling Hamiltonian. Noise with the 1/f power spectrum at low frequencies is instead responsible for defocusing processes and algebraic short-time behavior. In this paper, we identify the relevant decoherence times of an entangling operation due to the different decoherence channels originating from solid-state noise. Entanglement is quantified by concurrence, which we evaluate in an analytic form employing a multi-stage approach. The 'optimal' operating conditions of reduced sensitivity to noise sources are identified. We apply this analysis to a superconducting \sqrt{i-SWAP} gate for experimental noise spectra.Comment: 35 pages, 11 figure

    Translational control in the stress adaptive response of cancer cells: a novel role for the heat shock protein TRAP1

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    TNF receptor-associated protein 1 (TRAP1), the main mitochondrial member of the heat shock protein (HSP) 90 family, is induced in most tumor types and is involved in the regulation of proteostasis in the mitochondria of tumor cells through the control of folding and stability of selective proteins, such as Cyclophilin D and Sorcin. Notably, we have recently demonstrated that TRAP1 also interacts with the regulatory protein particle TBP7 in the endoplasmic reticulum (ER), where it is involved in a further extra-mitochondrial quality control of nuclear-encoded mitochondrial proteins through the regulation of their ubiquitination/degradation. Here we show that TRAP1 is involved in the translational control of cancer cells through an attenuation of global protein synthesis, as evidenced by an inverse correlation between TRAP1 expression and ubiquitination/degradation of nascent stress-protective client proteins. This study demonstrates for the first time that TRAP1 is associated with ribosomes and with several translation factors in colon carcinoma cells and, remarkably, is found co-upregulated with some components of the translational apparatus (eIF4A, eIF4E, eEF1A and eEF1G) in human colorectal cancers, with potential new opportunities for therapeutic intervention in humans. Moreover, TRAP1 regulates the rate of protein synthesis through the eIF2α pathway either under basal conditions or under stress, favoring the activation of GCN2 and PERK kinases, with consequent phosphorylation of eIF2α and attenuation of cap-dependent translation. This enhances the synthesis of selective stress-responsive proteins, such as the transcription factor ATF4 and its downstream effectors BiP/Grp78, and the cystine antiporter system xCT, thereby providing protection against ER stress, oxidative damage and nutrient deprivation. Accordingly, TRAP1 silencing sensitizes cells to apoptosis induced by novel antitumoral drugs that inhibit cap-dependent translation, such as ribavirin or 4EGI-1, and reduces the ability of cells to migrate through the pores of transwell filters. These new findings target the TRAP1 network in the development of novel anti-cancer strategies

    Italian Science Case for ALMA Band 2+3

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    The Premiale Project "Science and Technology in Italy for the upgraded ALMA Observatory - iALMA" has the goal of strengthening the scientific, technological and industrial Italian contribution to the Atacama Large Millimeter/submillimeter Array (ALMA), the largest ground based international infrastructure for the study of the Universe in the microwave. One of the main objectives of the Science Working Group (SWG) inside iALMA, the Work Package 1, is to develop the Italian contribution to the Science Case for the ALMA Band 2 or Band 2+3 receiver. ALMA Band 2 receiver spans from ~67 GHz (bounded by an opaque line complex of ozone lines) up to 90 GHz which overlaps with the lower frequency end of ALMA Band 3. Receiver technology has advanced since the original definition of the ALMA frequency bands. It is now feasible to produce a single receiver which could cover the whole frequency range from 67 GHz to 116 GHz, encompassing Band 2 and Band 3 in a single receiver cartridge, a so called Band 2+3 system. In addition, upgrades of the ALMA system are now foreseen that should double the bandwidth to 16 GHz. The science drivers discussed below therefore also discuss the advantages of these two enhancements over the originally foreseen Band 2 system.Comment: 43 pages, 21 figure

    The molecular gas properties in local Seyfert 2 galaxies

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    Aims. We present a multiwavelength study of the molecular gas properties of a sample of local Seyfert 2 galaxies to assess if, and to what extent, the presence of an active galactic nucleus (AGN) can affect the interstellar medium (ISM) properties in a sample of 33 local Seyfert 2 galaxies. Methods. We compare the molecular gas content (MH2) derived from new and archival low-J CO line measurements of a sample of AGN and a control sample of star-forming galaxies (SFGs). Both the AGN and the control sample are characterized in terms of host-galaxy properties, for example stellar and dust masses (M* and Mdust, respectively) and the star formation rate (SFR). We also investigate the effect of AGN activity on the emission of polycyclic aromatic hydrocarbon (PAH) molecules in the mid-infrared (MIR), a waveband where the dust-reprocessed emission from the obscured AGN contributes the most. Result. The AGN hosted in less massive galaxies (i.e., M* < 1010.5 M⊙; Mdust < 107.5 M⊙) show larger molecular gas contents with respect to SFGs that have the same stellar and dust masses. When comparing their depletion times (tdep ≈ MH2/SFR), AGN show tdep ∌ 0.3-1.0 Gyr, similar to the times observed in the control sample of SFGs. Seyfert 2 galaxies show fainter PAH luminosity the larger the dominance of the nuclear activity in the MIR. Conclusions. We find no clear evidence for a systematic reduction in the molecular gas reservoir at galactic scales in Seyfert galaxies with respect to SFGs. This is in agreement with recent studies that show that molecular gas content is only reduced in sub-kiloparsec-sized regions, where emission from the accreting supermassive black hole dominates. Nonetheless, we show that the impact of AGN activity on the ISM is clearly visible as a suppression of the PAH luminosity

    Spectroscopy of a Cooper-Pair box in the Autler-Townes configuration

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    A theoretical spectroscopic analysis of a microwave driven superconducting charge qubit (Cooper-pair box coupled) to an RLC oscillator model is performed. By treating the oscillator as a probe through the backreaction effect of the qubit on the oscillator circuit, we extract frequency splitting features analogous to the Autler-Townes effect from quantum optics, thereby extending the analogies between superconducting and quantum optical phenomenology. These features are found in a frequency band that avoids the need for high frequency measurement systems and therefore may be of use in qubit characterization and coupling schemes. In addition we find this frequency band can be adjusted to suit an experimental frequency regime by changing the oscillator frequency.Comment: 13 pages, 7 figures. v2: Revised version after referee comments. Accepted for publication by Physical Review

    Study of the effects of Pleurotuseryngii var. eryngii on heat shock proteins and cytokines levels in a mouse model of colon carcinoma

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    Medicinal mushrooms are wonderful source of nutraceuticals with a wide range of benefit for human health. The current anti-cancer therapy is not always target specific and often is associated with complications for patients. Therefore new effective and less toxic therapeutic approaches are needed. Heat shock proteins (Hsps) are highly expressed in a variety of cancer types contributing to tumor cell propagation. Here, we treated C26 colon cancer cells with a cold-water extracts of an edible mushrooms Pleurotuseryngii var. eryngii (Pleuery). Hsp90, 70, 60 and 27 levels were measured by western blotting and immunofluorescence analysis. Moreover, we evaluated Pleueryanti cancer effect in an animal model of ectopically-implanted C26 colon carcinoma. We prepared a mixture of lyophilized Pleuery with the mice standard diet, and the animals were daily fed with ~4g of the mix, 10 days before tumor implantation and until they died to draw a survival curve. A control group of mice fed with the standard diet, was used as control. We performed immunofluorescence and western blotting analysis for Hsps in the explanted tumors. Our results, showed that the extract affected cells viability at 0.5 \ub5g/\ub5l after both at 24 and 48 hours of treatments. Western blotting analysis of the cells lysate showed no changes in the Hsps protein levels except for Hsp60 which levels decreased at 24h of treatment but increased after 48h. Pleuery in the diet significantly extended the median survival compared to untreated mice. Moreover, western blotting analysis and immunofluorescence of the allograft tumors showed the decrease of Hsp90, 70 and Hsp60 levels while Hsp27 levels increased. Finally, qRT-PCR showed the down-regulation of IL-1 and IL-6 expression levels while the expression levels of TNF\u3b1 did not changed. These results led us to suppose the antioxidant and anti-inflammatory effects of Pleuery in vivo

    A painful tic convulsif due to double neurovascular impingement

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    Here we present the case of a 50-year-old man suffering from “painful tic convulsif”, on the left side of the face, i.e., left trigeminal neuralgia associated with ipsilateral hemifacial spasm. An angio-MRI scan showed a neurovascular confliction of left superior cerebellar artery with the ipsilateral V cranial nerve and of the left inferior cerebellar artery with the ipsilateral VII cranial nerve. Neurophysiological evaluation through esteroceptive blink reflex showed the involvement of left facial nerve. An initial carbamazepine treatment (800 mg/daily) was completely ineffective, so the patient was shifted to lamotrigine 50 b.i.d. that was able to reduce attacks from 4 to 6 times per day to 1 to 2 per week. Considering the good response to the drug, the neurosurgeon decided to delay surgical treatment

    Satellite tracking of leatherback and loggerhead sea turtles on the Southeast African coastline

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    The waters of southeast Africa contain important habitats for several sea turtle species, including the leatherback Dermochelys coriacea, loggerhead Caretta caretta, hawksbill Eretmochelys imbricata, green Chelonia mydas, and olive ridley turtle Lepidochelys olivacea. Many of these species are of conservation concern (Rakotoniria & Cooke, 1994; Thorson et al., 2012; Nel et al., 2013) and vulnerable to regional threats such as fisheries by-catch or boat-strikes (Bourjea et al., 2008; Grantham et al., 2008; Pusineri & Quillard, 2008). To help in the development of effective conservation plans for these species, many conservation or research organisations have used satellite transmitters to help identify critical habitats for sea turtles (Harris et al., 2015; Robinson et al., 2016). Here, we review the movement patterns of sea turtles that have been tracked through satellite telemetry from their nesting beaches on the east coast of South Africa
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