Neutral Hydrogen in the Bar of NGC 4151

Bars are thought to play a crucial role in the fueling of AGN (see e.g., Mundell et al., in these proceedings and references therein), and as part of a project to investigate this, we have studied the neutral hydrogen structure in the bar of the Seyfert 1.5 galaxy NGC 4151.High-sensitivity VLA observations have enabled us to image the neutral hydrogen emission from the bar of NGC 4151 in unprecedented detail, and is a continuation of the work by Pedlar et al. (1992).Figure 1 shows images of integrated neutral hydrogen emission. The large scale emission extends over approximately 20 kpc and the outer part consists of a well-defined two-armed spiral which originates from a fat bar at a radius of about 5 kpc. The bar shows complex structure, including two sharp features which are reminiscent of the shocks seen in many simulations, e.g., Athanassoula (1992). These features appear to join the central 1-kpc ring discovered by Vila-Vilaró et al. (1994), and for which there appears a partial counterpart in neutral hydrogen emission.

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Radio Observations of Neutral Hydrogen in Four Seyfert Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900005684 ◽

1972 ◽

Vol 44 ◽

pp. 269-270

Author(s):

Ronald J. Allen ◽

Bernard F. Darchy ◽

Robert Lauqué

Keyword(s):

Total Mass ◽

Large Scale ◽

Neutral Hydrogen ◽

Seyfert Galaxies ◽

Optical Spectra ◽

Optical Data ◽

Ngc 4151 ◽

Ngc 1068 ◽

Ngc 4051 ◽

Radial Outflow

The 21-cm wavelength radiation from neutral hydrogen in NGC 1068, NGC 3227, NGC 4051 and NGC 4151 has been observed with the large radio telescope at Nanĉay, France. Since the angular sizes of these galaxies are of the same order as the telescope right ascension beam-width, no information on the angular distribution of the neutral hydrogen was obtained. However the radial velocity distribution of the total hydrogen (the ‘integrated profile’) of the whole galaxy was measured for each of the four galaxies. The hydrogen masses and total masses can be calculated from these profiles using simple models of galaxy shapes and rotation curves.Optical spectra sometimes show evidence for explosive phenomena and radial outflow of gas in the central regions of Seyfert galaxies. We have examined the integrated radio profiles for indications of large-scale radial motions of neutral hydrogen in two ways. First, for all four galaxies observed, we compare the ratios of hydrogen mass to total mass with the values obtained from other galaxies (not Seyfert) of the same morphological type. Second, for these galaxies where the optical data are available, we compare the estimates of total mass obtained from the optical spectra with the estimates based on the width of the radio profile.We conclude from these comparisons that the integrated profile of NGC 1068 is unusually broad. One possible interpretation which is qualitatively consistent with the optical data is that an appreciable fraction (about ⅓) of the neutral hydrogen content of NGC 1068 is moving radially outward with velocities of about 200 km s−1 An indication of similar phenomena (although less extreme) is obtained for NGC 4051. The widths of the integrated profiles of NGC 3227 and NGC 4151 do not seem unusual.

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An EFEA Formulation for Computing Structural Response of Complex Structures

Noise Control and Acoustics ◽

10.1115/imece2005-81113 ◽

2005 ◽

Cited By ~ 5

Author(s):

Nick Vlahopoulos ◽

Aimin Wang ◽

Kuangcheng Wu

Keyword(s):

Test Data ◽

Large Scale ◽

Complex Structure ◽

Outer Part ◽

Structural Response ◽

External Flow ◽

Flow Induced Vibration ◽

Element Analysis ◽

Forcing Function ◽

Loading Effects

This paper presents a validation case study for an Energy Finite Element Analysis (EFEA) formulation through comparison to test data. The EFEA comprises a simulation tool for computing the structural response of a complex structure and the amount of the radiated power. When the forcing function originates from an external flow, then the EFEA can be used for computing the vibration and the noise created due to the external flow excitation. In the past the EFEA has been used for computing the flow induced vibration for a large scale vehicle. The EFEA formulation presented in this paper can account for periodic stiffeners, for partial fluid loading effects on the outer part of the structure, and for internal compartments filled with heavy fluid. The new developments are validated by computing the vibration induced on a 1/8 scale structure representative of an advanced hull concept, and by comparing the simulation results to the test data.

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Analysis and design of suitable model structures for activated sludge tanks with circulating flow

Water Science & Technology ◽

10.2166/wst.1999.0189 ◽

1999 ◽

Vol 39 (4) ◽

pp. 55-60 ◽

Cited By ~ 4

Author(s):

J. Alex ◽

R. Tschepetzki ◽

U. Jumar ◽

F. Obenaus ◽

K.-H. Rosenwinkel

Keyword(s):

Activated Sludge ◽

Large Scale ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

High Sensitivity ◽

Suitable Model ◽

Model Structure ◽

Analysis And Design ◽

Hydraulic Behaviour ◽

Model Structures

Activated sludge models are widely used for planning and optimisation of wastewater treatment plants and on line applications are under development to support the operation of complex treatment plants. A proper model is crucial for all of these applications. The task of parameter calibration is focused in several papers and applications. An essential precondition for this task is an appropriately defined model structure, which is often given much less attention. Different model structures for a large scale treatment plant with circulation flow are discussed in this paper. A more systematic method to derive a suitable model structure is applied to this case. Results of a numerical hydraulic model are used for this purpose. The importance of these efforts are proven by a high sensitivity of the simulation results with respect to the selection of the model structure and the hydraulic conditions. Finally it is shown, that model calibration was possible only by adjusting to the hydraulic behaviour and without any changes of biological parameters.

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Analytical Validation and Clinical Application of Rapid Serological Tests for SARS-CoV-2 Suitable for Large-Scale Screening

Diagnostics ◽

10.3390/diagnostics11050869 ◽

2021 ◽

Vol 11 (5) ◽

pp. 869

Author(s):

Amedeo De Nicolò ◽

Valeria Avataneo ◽

Jessica Cusato ◽

Alice Palermiti ◽

Jacopo Mula ◽

...

Keyword(s):

Early Diagnosis ◽

Real Time Pcr ◽

Large Scale ◽

High Sensitivity ◽

Analytical Validation ◽

Pcr Assay ◽

Serological Tests ◽

Flow Test ◽

Lateral Flow Test ◽

Large Scale Screening

Recently, large-scale screening for COVID-19 has presented a major challenge, limiting timely countermeasures. Therefore, the application of suitable rapid serological tests could provide useful information, however, little evidence regarding their robustness is currently available. In this work, we evaluated and compared the analytical performance of a rapid lateral-flow test (LFA) and a fast semiquantitative fluorescent immunoassay (FIA) for anti-nucleocapsid (anti-NC) antibodies, with the reverse transcriptase real-time PCR assay as the reference. In 222 patients, LFA showed poor sensitivity (55.9%) within two weeks from PCR, while later testing was more reliable (sensitivity of 85.7% and specificity of 93.1%). Moreover, in a subset of 100 patients, FIA showed high sensitivity (89.1%) and specificity (94.1%) after two weeks from PCR. The coupled application for the screening of 183 patients showed satisfactory concordance (K = 0.858). In conclusion, rapid serological tests were largely not useful for early diagnosis, but they showed good performance in later stages of infection. These could be useful for back-tracing and/or to identify potentially immune subjects.

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GASTON: Galactic Star Formation with NIKA2. Evidence for the mass growth of star-forming clumps

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab200 ◽

2021 ◽

Author(s):

A J Rigby ◽

N Peretto ◽

R Adam ◽

P Ade ◽

M Anderson ◽

...

Keyword(s):

Star Formation ◽

Large Scale ◽

Galactic Plane ◽

High Sensitivity ◽

High Mass ◽

Evolutionary Stage ◽

Mass Star ◽

Mass Growth ◽

Star Forming ◽

Compact Source

Abstract Determining the mechanism by which high-mass stars are formed is essential for our understanding of the energy budget and chemical evolution of galaxies. By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we have conducted high-sensitivity and large-scale mapping of a fraction of the Galactic plane in order to search for signatures of the transition between the high- and low-mass star-forming modes. Here, we present the first results from the Galactic Star Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m telescope which is mapping ≈2 deg2 of the inner Galactic plane (GP), centred on ℓ = 23${_{.}^{\circ}}$9, b = 0${_{.}^{\circ}}$05, as well as targets in Taurus and Ophiuchus in 1.15 and 2.00 mm continuum wavebands. In this paper we present the first of the GASTON GP data taken, and present initial science results. We conduct an extraction of structures from the 1.15 mm maps using a dendrogram analysis and, by comparison to the compact source catalogues from Herschel survey data, we identify a population of 321 previously-undetected clumps. Approximately 80 per cent of these new clumps are 70 μm-quiet, and may be considered as starless candidates. We find that this new population of clumps are less massive and cooler, on average, than clumps that have already been identified. Further, by classifying the full sample of clumps based upon their infrared-bright fraction – an indicator of evolutionary stage – we find evidence for clump mass growth, supporting models of clump-fed high-mass star formation.

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A New Hybrid Inversion Method for 2D Nuclear Magnetic Resonance Combining TSVD and Tikhonov Regularization

Journal of Imaging ◽

10.3390/jimaging7020018 ◽

2021 ◽

Vol 7 (2) ◽

pp. 18

Author(s):

Germana Landi ◽

Fabiana Zama ◽

Villiam Bortolotti

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Tikhonov Regularization ◽

Large Scale ◽

Regularization Parameter ◽

High Sensitivity ◽

Inversion Method ◽

Nmr Relaxometry ◽

Value Decomposition ◽

Nuclear Magnetic

This paper is concerned with the reconstruction of relaxation time distributions in Nuclear Magnetic Resonance (NMR) relaxometry. This is a large-scale and ill-posed inverse problem with many potential applications in biology, medicine, chemistry, and other disciplines. However, the large amount of data and the consequently long inversion times, together with the high sensitivity of the solution to the value of the regularization parameter, still represent a major issue in the applicability of the NMR relaxometry. We present a method for two-dimensional data inversion (2DNMR) which combines Truncated Singular Value Decomposition and Tikhonov regularization in order to accelerate the inversion time and to reduce the sensitivity to the value of the regularization parameter. The Discrete Picard condition is used to jointly select the SVD truncation and Tikhonov regularization parameters. We evaluate the performance of the proposed method on both simulated and real NMR measurements.

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Health monitoring sensor placement optimization based on initial sensor layout using improved partheno-genetic algorithm

Advances in Structural Engineering ◽

10.1177/1369433220947198 ◽

2020 ◽

pp. 136943322094719

Author(s):

Xianrong Qin ◽

Pengming Zhan ◽

Chuanqiang Yu ◽

Qing Zhang ◽

Yuantao Sun

Keyword(s):

Genetic Algorithm ◽

Health Monitoring ◽

Large Scale ◽

Complex Structure ◽

Sensor Placement ◽

Placement Problem ◽

Optimal Sensor Placement ◽

Placement Optimization ◽

Sensor Placement Optimization ◽

Sensor Locations

Optimal sensor placement is an important component of a reliability structural health monitoring system for a large-scale complex structure. However, the current research mainly focuses on optimizing sensor placement problem for structures without any initial sensor layout. In some cases, the experienced engineers will first determine the key position of whole structure must place sensors, that is, initial sensor layout. Moreover, current genetic algorithm or partheno-genetic algorithm will change the position of the initial sensor locations in the iterative process, so it is unadaptable for optimal sensor placement problem based on initial sensor layout. In this article, an optimal sensor placement method based on initial sensor layout using improved partheno-genetic algorithm is proposed. First, some improved genetic operations of partheno-genetic algorithm for sensor placement optimization with initial sensor layout are presented, such as segmented swap, reverse and insert operator to avoid the change of initial sensor locations. Then, the objective function for optimal sensor placement problem is presented based on modal assurance criterion, modal energy criterion, and sensor placement cost. At last, the effectiveness and reliability of the proposed method are validated by a numerical example of a quayside container crane. Furthermore, the sensor placement result with the proposed method is better than that with effective independence method without initial sensor layout and the traditional partheno-genetic algorithm.

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