36 research outputs found

    Observational constraints on the types of cosmic strings

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    This paper is aimed at setting observational limits to the number of cosmic strings (Nambu-Goto, Abelian-Higgs, semilocal) and other topological defects (textures). Radio maps of CMB anisotropy, provided by the space mission Planck for various frequencies, were filtered and then processed by the method of convolution with modified Haar functions (MHF) to search for cosmic string candidates. This method was designed to search for solitary strings, without additional assumptions about the presence of networks of such objects. The sensitivity of the MHF method is δT≈10μK\delta T \approx 10 \mu K in a background of δT≈100μK\delta T \approx 100 \mu K. The comparison of these with previously known results on search string network shows that strings can only be semilocal in an amount of 1÷51 \div 5, with the upper restriction on individual strings tension (linear density) of Gμ/c2≤7.36⋅10−7G\mu/c^2 \le 7.36 \cdot 10^{-7}. The texture model is also legal. There are no strings with Gμ/c2>7.36⋅10−7G\mu/c^2 > 7.36 \cdot 10^{-7}. However, comparison with the data for the search of non-Gaussian signals shows that the presence of several (up to 3) of Nambu-Goto strings is also possible. For Gμ/c2≤4.83⋅10−7G\mu/c^2 \le 4.83 \cdot 10^{-7} the MHF method is ineffective because of unverifiable spurious string candidates. Thus the existence of strings with tensions Gμ/c2≤4.83⋅10−7G\mu/c^2 \le 4.83 \cdot 10^{-7} is not prohibited but it is beyond the Planck data possibilities.Comment: 15 pages, 10 figures; accepted by the European Physical Journal

    The Italian Earthquakes and Tsunami Monitoring and Surveillance Systems

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    The Osservatorio Nazionale Terremoti (ONT) is the Italian seismic operational centre for monitoring earthquake, it is part of Istituto Nazionale di Geofisica e Vulcanologia (INGV) the largest Italian research institution, with focus in Earth Sciences. INGV runs the Italian National Seismic Network (network code IV) and other networks at national scale for monitoring earthquakes and tsunami. INGV is a primary node of European Integrated Data Archive (EIDA) for archiving and distributing, continuous, quality checked seismic waveforms (strong motion and weak motion recordings). ONT designed the data acquisition system to accomplish, in near-real-time, automatic earthquake detection, hypocentre and magnitude determination and evaluation of moment tensors, shake maps and other products. Database archiving of all parametric results are closely linked to the existing procedures of the INGV seismic monitoring environment and surveillance procedures. ONT organize the Italian earthquake surveillance service and the tsunami alert service (INGV is Tsunami Service Provider of the ICG/NEAM for the entire Mediterranean basin). We provide information to the Dipartimento di Protezione Civile (DPC) and to several Mediterranean countries. Earthquakes information are revised routinely by the analysts of the Italian Seismic Bulletin. The results are published on the web and are available to the scientific community and the general public.PublishedMontreal1SR TERREMOTI - Sorveglianza Sismica e Allerta Tsunam

    Metastatic group 3 medulloblastoma is driven by PRUNE1 targeting NME1-TGF-β-OTX2-SNAIL via PTEN inhibition.

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    Genetic modifications during development of paediatric groups 3 and 4 medulloblastoma are responsible for their highly metastatic properties and poor patient survival rates. PRUNE1 is highly expressed in metastatic medulloblastoma group 3, which is characterized by TGF-β signalling activation, c-MYC amplification, and OTX2 expression. We describe the process of activation of the PRUNE1 signalling pathway that includes its binding to NME1, TGF-β activation, OTX2 upregulation, SNAIL (SNAI1) upregulation, and PTEN inhibition. The newly identified small molecule pyrimido-pyrimidine derivative AA7.1 enhances PRUNE1 degradation, inhibits this activation network, and augments PTEN expression. Both AA7.1 and a competitive permeable peptide that impairs PRUNE1/NME1 complex formation, impair tumour growth and metastatic dissemination in orthotopic xenograft models with a metastatic medulloblastoma group 3 cell line (D425-Med cells). Using whole exome sequencing technology in metastatic medulloblastoma primary tumour cells, we also define 23 common 'non-synonymous homozygous' deleterious gene variants as part of the protein molecular network of relevance for metastatic processes. This PRUNE1/TGF-β/OTX2/PTEN axis, together with the medulloblastoma-driver mutations, is of relevance for future rational and targeted therapies for metastatic medulloblastoma group 3

    Building the largest spectroscopic sample of ultra-compact massive galaxies with the Kilo Degree Survey

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    Ultra-compact massive galaxies UCMGs, i.e. galaxies with stellar masses M∗>8×1010M⊙M_{*} > 8 \times 10^{10} M_{\odot} and effective radii Re<1.5R_{e} < 1.5 kpc, are very rare systems, in particular at low and intermediate redshifts. Their origin as well as their number density across cosmic time are still under scrutiny, especially because of the paucity of spectroscopically confirmed samples. We have started a systematic census of UCMG candidates within the ESO Kilo Degree Survey, together with a large spectroscopic follow-up campaign to build the largest possible sample of confirmed UCMGs. This is the third paper of the series and the second based on the spectroscopic follow-up program. Here, we present photometrical and structural parameters of 33 new candidates at redshifts 0.15≲z≲0.50.15 \lesssim z \lesssim 0.5 and confirm 19 of them as UCMGs, based on their nominal spectroscopically inferred M∗M_{*} and ReR_{e}. This corresponds to a success rate of ∼58%\sim 58\%, nicely consistent with our previous findings. The addition of these 19 newly confirmed objects, allows us to fully assess the systematics on the system selection, and finally reduce the number density uncertainties. Moreover, putting together the results from our current and past observational campaigns and some literature data, we build the largest sample of UCMGs ever collected, comprising 92 spectroscopically confirmed objects at 0.1≲z≲0.50.1 \lesssim z \lesssim 0.5. This number raises to 116, allowing for a 3σ3\sigma tolerance on the M∗M_{*} and ReR_{e} thresholds for the UCMG definition. For all these galaxies we have estimated the velocity dispersion values at the effective radii which have been used to derive a preliminary mass-velocity dispersion correlation

    Bollettino Sismico Italiano: Analisys of Early Aftershocks of the 2016 MW 6.0 Amatrice, MW 5.9 Visso and MW 6.5 Norcia earthquakes in Central Italy

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    The Amatrice-Visso-Norcia seismic sequence is the most important of the last 30 years in Italy. The seismic sequence started on 24 August, 2016 and still is ongoing in central Apennines. At the end of February 2017 more than 57,000 events were located, 80,000 events up to the end of September 2017 (Fig. 1). The mainshocks of the sequence occurred on 24 August 2016 (Mw 6.0 and Mw 5.4), 26 October 2016 (Mw 5.4 and Mw 5.9), 30 October 2016 (Mw 6.5), 18 January 2017 (four earthquakes Mw≥ 5.0). In this seismic sequence, all the waveforms recorded by temporary stations deployed by the SISMIKO emergency group (stations T12**; Moretti et al., 2016) where available in real- time at the surveillance room of INGV. Because of the high level of seismicity and the dense seismic network installed in the region, more than 150 events per day were located at the end of February 2017; still 60 events per day were located up to the end of August 2017.The Amatrice-Visso-Norcia is the most important seismic sequence since 2015, the time when the analysis procedures of the BSI group (Bollettino Sismico Italiano) were revised (Nardi et al., 2015). BSI is now available every four months on the web: bulletins contain revised earthquakes (location and magnitude) with ML≥ 1.5, quasi-real time revision of ML≥ 3.5 earthquakes and phase arrivals from waveforms recorded on seismic stations available from the European Integrated Data Archive (EIDA), (Mazza et al., 2012). These last procedures allow the integration of signals from temporary seismic stations (Moretti et al., 2014) installed by the emergency group SISMIKO (Moretti and Sismiko working group, 2016), even when they are not in real time transmission, if they are rapidly archived in EIDA, together with real time signals from the seismic stations of the permanent INGV network. The analysis strategy of the BSI group for the Amatrice -Visso - Norcia seismic sequence (AVN.s.s in the following) was to select the earthquakes located in the box with min/max latitude: 42.2/43.2 - and min/max longitude: 12.4/14.1 to prepare a special volume of BSI on the seismic sequence.PublishedTrieste, Italy1SR. TERREMOTI - Servizi e ricerca per la Societ

    Bollettino Sismico Italiano: maggio - agosto 2016

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    Il 24 agosto 2016 un terremoto di magnitudo 6.0 ha dato inizio ad una sequenza sismica in Italia centrale, che ha generato decine di migliaia di eventi sismici. Per l’analisi e revisione di questa sequenza si rimanda ad un uscita speciale del BSI prevista per fine 2017(S_BSI_CI). In questo quadrimestre e nel successivo gli eventi nella zona della sequenza sono quelli localizzati nella sala di sorveglianza. Solo gli eventi con M>= 3.5, e pochi altri (vedi Marchetti et al. Annals of Geophys. DOI: 10.4401/ag6116) sono stati rivisti dal BSI.Nel secondo quadrimestre 2016 si sono verificati sedici eventi di magnitudo superiore a 4.0 (ML) rivisti dagli analisti del BSI uno vicino alle coste tunisine quindi fuori dal territorio nazionale; l’evento di Mw 4.1 che è avvenuto il 30 maggio in provincia di Terni vicino al Lago di Bolsena (lat=42.7, lon=11.98 ad una profondità di 8 km) e 14 eventi nella zona della sequenza nell’ultima settimana del quadrimestre: il 24 agosto 2016 si è verificato l’evento di magnitudo ML=6.0 (Mw=6.0) che ha iniziato una sequenza sismica per la quale sono stati localizzati decine di migliaia di terremoti e che alla fine di ottobre 2016 ha generato eventi persino più forti (fino a Mw=6.5) della prima scossa.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublished4IT. Banche dat
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