Embedded AGN and star formation in the central 80 pc of IC 3639

[Abridged] Methods: We use interferometric observations in the $N$-band with VLTI/MIDI to resolve the mid-IR nucleus of IC 3639. The origin of the nuclear infrared emission is determined from: 1) the comparison of the correlated fluxes from VLTI/MIDI with the fluxes measured at subarcsec resolution (VLT/VISIR, VLT/ISAAC); 2) diagnostics based on IR fine-structure line ratios, the IR continuum emission, IR bands produced by polycyclic aromatic hydrocarbons (PAH) and silicates; and 3) the high-angular resolution spectral energy distribution. Results: The unresolved flux of IC 3639 is $90 \pm 20\, \rm{mJy}$ at $10.5\, \rm{\mu m}$, measured with three different baselines in VLTI (UT1-UT2, UT3-UT4, and UT2-UT3; $46$-$58\, \rm{m}$), making this the faintest measurement so far achieved with mid-IR interferometry. The correlated flux is a factor of $3$-$4$ times fainter than the VLT/VISIR total flux measurement. The observations suggest that most of the mid-IR emission has its origin on spatial scales between $10$ and $80\, \rm{pc}$ ($40$-$340\, \rm{mas}$). A composite scenario where the star formation component dominates over the AGN is favoured by the diagnostics based on ratios of IR fine-structure emission lines, the shape of the IR continuum, and the PAH and silicate bands. Conclusions: A composite AGN-starburst scenario is able to explain both the mid-IR brightness distribution and the IR spectral properties observed in the nucleus of IC 3639. The nuclear starburst would dominate the mid-IR emission and the ionisation of low-excitation lines (e.g. [NeII]$_{12.8 \rm{\mu m}}$) with a net contribution of $\sim 70\%$. The AGN accounts for the remaining $\sim 30\%$ of the mid-IR flux, ascribed to the unresolved component in the MIDI observations, and the ionisation of high-excitation lines (e.g. [NeV]$_{14.3 \rm{\mu m}}$ and [OIV]$_{25.9 \rm{\mu m}}$).Comment: Accepted for publication in A&

The central parsecs of M87: jet emission and an elusive accretion disc

We present the first simultaneous spectral energy distribution (SED) of M87 core at a scale of 0.4 arcsec ($\sim 32\, \rm{pc}$) across the electromagnetic spectrum. Two separate, quiescent, and active states are sampled that are characterized by a similar featureless SED of power-law form, and that are thus remarkably different from that of a canonical active galactic nuclei (AGN) or a radiatively inefficient accretion source. We show that the emission from a jet gives an excellent representation of the core of M87 core covering ten orders of magnitude in frequency for both the active and the quiescent phases. The inferred total jet power is, however, one to two orders of magnitude lower than the jet mechanical power reported in the literature. The maximum luminosity of a thin accretion disc allowed by the data yields an accretion rate of $< 6 \times 10^{-5}\, \rm{M_\odot \, yr^{-1}}$, assuming 10% efficiency. This power suffices to explain M87 radiative luminosity at the jet-frame, it is however two to three order of magnitude below that required to account for the jet's kinetic power. The simplest explanation is variability, which requires the core power of M87 to have been two to three orders of magnitude higher in the last 200 yr. Alternatively, an extra source of power may derive from black hole spin. Based on the strict upper limit on the accretion rate, such spin power extraction requires an efficiency an order of magnitude higher than predicted from magnetohydrodynamic simulations, currently in the few hundred per cent range.Comment: 18 pages, 6 figures. Accepted for publication in MNRA

Computer Tomography 3D Edge Detection Comparative for Metrology Applications

AbstractThe CT process for metrology applications is very complex because has many factors that influence the loss of accuracy during CT measurements. One of the most critical is the edge detection also called surface extraction or image segmentation, which is the process of surface formation from the CT‘s volume data that represents a grey value corresponding to the mass attenuation coefficient of the object material. This paper presents different edge detection methods commonly used in areas like machine and computer vision and they are analyzed as an alternative to the common methods used in CT for metrology applications. Each method is described and analyzed separately in order to highlight its advantages and disadvantages from a metrological point of view. An experimental comparative between two of them is also shown

A surface extraction analysis in a multi-material test part for computed tomography in metrology applications

The main advantage of Computed Tomography is the capability of making measurements of non-accessible internal features in a test piece. One of the cases that can usually be found in this sense is the contact zone between two elements that are forming a common surface boundary, where the main complexity is to determine which surface belongs to which piece. Nowadays, this kind of surfaces are measurable only by utilizing Computed Tomography, taking into account that the characteristics of the Tomography can significantly vary depending on the material of the elements that are in contact. In this article a piece that has two different interfaces is analyzed: a Piece in contact with Air, and Material A in contact with Material B. Three different surface extraction algorithms are analyzed for multi-material parts, Threshold, Canny and Deriche, and the results and conclusions obtained are presented

Yield of Outpatient Sleep EEG for Epileptiform Alterations' Detection in Children.

PURPOSE: Ambulatory EEGs in children are frequently ordered as sleep studies. However, the yield according to different clinical situations has received little attention to date. The authors aimed to quantify the added value in terms of detection of epileptiform features of an EEG containing sleep, as compared with only wakefulness, according to the referral diagnoses. METHODS: The authors retrospectively selected consecutive outpatients' EEG recordings of patients between 6 months to 16 years old, performed between January 2014 and February 2015. The authors excluded those lacking at least 10 minutes of waking and/or at least 5 minutes of behavioral sleep. Interictal epileptiform activity (IEA) in wakefulness and sleep was compared among referral suspected diagnoses. Additional yield of sleep was considered if at least one of the following was observed: appearance of interictal epileptiform activity or increase by &gt;50%; interictal epileptiform activity change in localization or morphology, seizure occurrence. RESULTS: A total of 425 recordings (mean age 6.9 ± 4.7 years) were analyzed. Of them, 194 (45.6%) presented an additional yield during sleep, which was dependent on the occurrence of IEA during wakefulness: 77/251 (30.7%) in those without versus 117/174 (67.2%) in those with wakefulness IEA (P &lt; 0.001, χ). The yield was markedly lower in studies performed for nonepileptic referral diagnoses (7% vs. 43% to 100%; P &lt; 0.001, Fisher). CONCLUSIONS: When wakefulness EEG lacks epileptiform features, the yield of sleep EEG in our pediatric population appeared modest, especially in patients without a suspected epileptic syndrome. This information may be used to optimize the request of sleep EEG in children

Inactivation of Expression of Gene 4 of Mouse Hepatitis Virus Strain JHM Does Not Affect Virulence in the Murine CNS

AbstractThe protein encoded by ORF 4 of mouse hepatitis virus (MHV) is not required for growth of some strains in tissue culture cells, but its role in pathogenesis in the murine host has not been defined previously in a controlled manner. MHV strain JHM causes acute and chronic neurological diseases in susceptible strains of rodents. To genetically manipulate the structural proteins of this and other strains of MHV, we have generalized an interspecies-targeted RNA recombination selection that was originally developed for the A59 strain of MHV. Using this approach, a recombinant MHV–JHM was constructed in which gene 4 was genetically inactivated. Virus lacking gene 4 expression replicated in tissue culture cells with similar kinetics to recombinant virus in which gene 4 expression was not disrupted. Both types of viruses exhibited similar virulence when analyzed in a murine model of encephalitis. These results establish a targeted recombination system for inserting mutations into MHV–JHM. Furthermore, the protein encoded by ORF 4 is not essential for growth in tissue culture cells or in the CNS of the infected host

Analysis of surface extraction methods based on gradient operators for computed tomography in metrology applications

Among the multiple factors influencing the accuracy of Computed Tomography measurements, the surface extraction process is a significant contributor. The location of the surface for metrological applications is generally based on the definition of a gray value as a characteristic of similarity to define the regions of interest. A different approach is to perform the detection or location of the surface based on the discontinuity or gradient. In this paper, an adapted 3D Deriche algorithm based on gradient information is presented and compared with a previously developed adapted Canny algorithm for different surface types. Both algorithms have been applied to nine calibrated workpieces with different geometries and materials. Both the systematic error and measurement uncertainty have been determined. The results show a significant reduction of the deviations obtained with the Deriche-based algorithm in the dimensions defined by flat surfaces