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309 results on '"Heymann, F."'

1. Paradigmatic examples for testing models of optical light polarization by spheroidal dust

Author

Peest, C., Siebenmorgen, R., Heymann, F., Vannieuwenhuyse, T., and Baes, M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We present a general framework on how the polarization of radiation due to scattering, dichroic extinction, and birefringence of aligned spheroidal dust grains can be implemented and tested in 3D Monte Carlo radiative transfer (MCRT) codes. We derive a methodology for solving the radiative transfer equation governing the changes of the Stokes parameters in dust-enshrouded objects. We utilize the M\"uller matrix, and the extinction, scattering, linear, and circular polarization cross sections of spheroidal grains as well as electrons. An established MCRT code is used and its capabilities are extended to include the Stokes formalism. We compute changes in the polarization state of the light by scattering, dichroic extinction, and birefringence on spheroidal grains. The dependency of the optical depth and the albedo on the polarization is treated. The implementation of scattering by spheroidal grains both for random walk steps as well as for directed scattering (peel-off) are described. The observable polarization of radiation of the objects is determined through an angle binning method for photon packages leaving the model space as well as through an inverse ray-tracing routine for the generation of images. We present paradigmatic examples for which we derive analytical solutions of the optical light polarization by spheroidal dust particles. These tests are suited for benchmark verification of MCpol and other such codes, and allow to quantify the numerical precision reached. We demonstrate that MCpol is in excellent agreement to within 0.1% of the Stokes parameters when compared to the analytical solutions., Comment: A&A accepted by Editor

Published
2023
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7. Mid-infrared spectroscopy of high-redshift 3CRR sources

Author

Leipski, C., Haas, M., Willner, S. P., Ashby, M. L. N., Wilkes, B. J., Fazio, G. G., Antonucci, R., Barthel, P., Chini, R., Ogle, P., Siebenmorgen, R., and Heymann, F.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Using the Spitzer Space Telescope, we have obtained rest frame 9-16mu spectra of 11 quasars and 9 radio galaxies from the 3CRR catalog at redshifts 1.0

Published
2010
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8. Near- and mid-infrared photometry of high-redshift 3CR sources

Author

Haas, M., Willner, S. V. P., Heymann, F., Ashby, M. L. N., Fazio, G. G., Wilkes, B. J., Chini, R., and Siebenmorgen, R.

Subjects
Astrophysics
Abstract

Using the Spitzer Space Telescope, we have obtained 3.6--24 micron photometry of 38 radio galaxies and 24 quasars from the 3CR catalog at redshift 1

Published
2008
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9. A near-infrared survey of the entire R Corona Australis cloud

Author

Haas, M., Heymann, F., Domke, I., Drass, H., Chini, R., and Hoffmeister, V.

Subjects
Astrophysics
Abstract

To understand low- to intermediate-mass star-formation in the nearby R CrA molecular cloud, we try to identify the stellar content that is accessible with near-infrared observations. We obtained a JHK band mosaic of 10 x 60 arcmin square covering the entire RCrA molecular cloud with unprecedented sensitivity. We present a catalogue of about 3500 near-infrared sources fainter than the saturation limit K = 10 mag, reaching K = 18mag. We analysed the extended sources by inspecting their morphology and point sources by means of colour-colour and colour-magnitude diagrams. Additionally, we compared the extinction inferred from the NIR data with the line-of-sight dust emission at 1.2 mm. Sources towards high dust emission but relatively low H-K show a projected mm-exces; these sources are either immediately surrounded by cold circumstellar material or, if too red to be a true foreground object, they are embedded in the front layer of the 1.2 mm emitting dust cloud. In both cases they are most likely associated with the cloud., Comment: 11 pages, 12 Figures, accepted by Astronomy and Astrophysics

Published
2008
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11. M cell maturation and cDC activation determine the onset of adaptive immune priming in the neonatal Peyer’s patch

Author

Torow, N., Li, R., Hitch, T.C.A., Mingels, C., Al Bounny, S., van Best, N., Stange, E.-L., Simons, B., Maié, T., Rüttger, L., Gubbi, N.M.K.P., Abbott, D.A., Benabid, A., Gadermayr, M., Runge, S., Treichel, N., Merhof, D., Rosshart, S.P., Jehmlich, Nico, Hand, T.W., von Bergen, Martin, Heymann, F., Pabst, O., Clavel, T., Tacke, F., Lelouard, H., Gesteira Costa, I., Hornef, M.W., Torow, N., Li, R., Hitch, T.C.A., Mingels, C., Al Bounny, S., van Best, N., Stange, E.-L., Simons, B., Maié, T., Rüttger, L., Gubbi, N.M.K.P., Abbott, D.A., Benabid, A., Gadermayr, M., Runge, S., Treichel, N., Merhof, D., Rosshart, S.P., Jehmlich, Nico, Hand, T.W., von Bergen, Martin, Heymann, F., Pabst, O., Clavel, T., Tacke, F., Lelouard, H., Gesteira Costa, I., and Hornef, M.W.

Abstract

Early-life immune development is critical to long-term host health. However, the mechanisms that determine the pace of postnatal immune maturation are not fully resolved. Here, we analyzed mononuclear phagocytes (MNPs) in small intestinal Peyer’s patches (PPs), the primary inductive site of intestinal immunity. Conventional type 1 and 2 dendritic cells (cDC1 and cDC2) and RORgt+ antigen-presenting cells (RORgt+ APC) exhibited significant age-dependent changes in subset composition, tissue distribution, and reduced cell maturation, subsequently resulting in a lack in CD4+ T cell priming during the postnatal period. Microbial cues contributed but could not fully explain the discrepancies in MNP maturation. Type I interferon (IFN) accelerated MNP maturation but IFN signaling did not represent the physiological stimulus. Instead, follicle-associated epithelium (FAE) M cell differentiation was required and sufficient to drive postweaning PP MNP maturation. Together, our results highlight the role of FAE M cell differentiation and MNP maturation in postnatal immune development.

Published
2023

12. Neonatal Peyer's patch cDC activation as a pacemaker of postnatal immune maturation

Author

Torow, N., Li, R., Hitch, T., Mingels, C., Al Bounny, S., van Best, N., Stange, E.-L., Benabid, A., Rüttger, L., Gadermayr, M., Runge, S., Treichel, N., Merhof, D., Rosshart, S., Jehmlich, Nico, von Bergen, Martin, Heymann, F., Clavel, T., Tacke, F., Lelouard, H., Costa, I., Torow, N., Li, R., Hitch, T., Mingels, C., Al Bounny, S., van Best, N., Stange, E.-L., Benabid, A., Rüttger, L., Gadermayr, M., Runge, S., Treichel, N., Merhof, D., Rosshart, S., Jehmlich, Nico, von Bergen, Martin, Heymann, F., Clavel, T., Tacke, F., Lelouard, H., and Costa, I.

Abstract

no abstract

Published
2022

13. Neonatal Peyer’s patch cDC activation as a pacemaker of postnatal immune maturation

Author

Torow, N., primary, Li, R., additional, Hitch, T., additional, Mingels, C., additional, Bounny, S. al, additional, van Best, N., additional, Stange, E.-L., additional, Benabid, A., additional, Rüttger, L., additional, Gadermayr, M., additional, Runge, S., additional, Treichel, N., additional, Merhof, D., additional, Rosshart, S., additional, Jehmlich, N., additional, von Bergen, M., additional, Heymann, F., additional, Clavel, T., additional, Tacke, F., additional, Lelouard, H., additional, Costa, I., additional, and Hornef, M. W., additional

Published
2022
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14. Neonatal Peyer's patch cDC activation as a pacemaker of postnatal immune maturation

Author

Torow, Natalia, Li, Ronghui, Hitch, Thomas, Mingels, Clemens, Al Bounny, Shahed, van Best, Niels, Stange, Eva-Lena, Benabid, Adam, Ruettger, Lennart, Gadermayr, Michael, Runge, S., Treichel, N., Merhof, D., Rosshart, S., Jehmlich, N., von Bergen, M., Heymann, F., Clavel, T., Tacke, F., Lelouard, H., Costa, Ivan G., and Hornef, M. W.

Abstract

Cold Spring Harbor : Cold Spring Harbor Laboratory, bioRxiv : the preprint server for biology 1-41 (2022). doi:10.1101/2022.03.03.482839, Published by Cold Spring Harbor Laboratory, Cold Spring Harbor

Published
2022
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17. Practical Aspects of Cavitation [and Discussion]

Author

Hobbs, J. M., Hickling, R., Brunton, J. H., Ellis, A. T., Gadd, G. E., Benjamin, T. B., Silverleaf, A., Smith, A. V., Hammitt, F. G., Tuffrey, A., Heymann, F. J., Popple, R. G., Broom, T., Rasmussen, R. E. H., Hobbs, J. M., Marriott, J. B., Pearson, D., Tabor, D., Fyall, A. A., Barnard, B. J. S., and Cooper, G. A.

Published
1966

23. Lattice reformulation cuts

Author

Aardal, K. (Karen), Lodi, A. (Andrea), Tramontani, A. (Andrea), Heymann, F. (Frederik) von, Wolsey, L.A. (Laurence), Aardal, K. (Karen), Lodi, A. (Andrea), Tramontani, A. (Andrea), Heymann, F. (Frederik) von, and Wolsey, L.A. (Laurence)

Abstract

Here we consider the question whether the lattice reformulation of a linear integer program can be used to produce effective cutting planes. In particular, we aim at deriving split cuts that cut off more of the integrality gap than Gomory mixed-integer (GMI) inequalities generated from LP-tableaus, while being less computationally demanding than generating the split closure. We consider integer programs (IPs) in the form max{ Ax=b x =Zn+}, where the reformulation takes the form max\{cx +cQ> -xu u =Zn-m Z n - m\}, where Q is an n (n - m) integer matrix. Working on an optimal LP-tableau in the u -space allows us to generate n - m GMIs in addition to the m GMIs associated with the optimal tableau in the x space. These provide new cuts that can be seen as GMIs associated to n - m nonelementary split directions associated with the reformulation matrix \Q . On the other hand it turns out that the corner polyhedra associated to an LP basis and the GMI or split closures are the same whether working in the x or u spaces. Our theoretical derivations are accompanied by an illustrative computational study. The computations show that the effectiveness of the cuts generated by this approach depends on the quality of the reformulation obtained by the reduced basis algorithm used to generate Q and that it is worthwhile to generate several rounds of such cuts. However, the effectiveness of the cuts deteriorates as the number of constraints is increased.

Published
2021
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26. Novel 3D analysis using optical tissue clearing documents the evolution of murine rapidly progressive glomerulonephritis.

Author

Moeller M.J., Floege J., Kramann R., Kurts C., Bertram J.F., Spehr M., Nikolic-Paterson D.J., Puelles V.G., Fleck D., Ortz L., Papadouri S., Strieder T., Bohner A.M.C., van der Wolde J.W., Vogt M., Saritas T., Kuppe C., Fuss A., Menzel S., Klinkhammer B.M., Muller-Newen G., Heymann F., Decker L., Braun F., Kretz O., Huber T.B., Susaki E.A., Ueda H.R., Boor P., Moeller M.J., Floege J., Kramann R., Kurts C., Bertram J.F., Spehr M., Nikolic-Paterson D.J., Puelles V.G., Fleck D., Ortz L., Papadouri S., Strieder T., Bohner A.M.C., van der Wolde J.W., Vogt M., Saritas T., Kuppe C., Fuss A., Menzel S., Klinkhammer B.M., Muller-Newen G., Heymann F., Decker L., Braun F., Kretz O., Huber T.B., Susaki E.A., Ueda H.R., and Boor P.

Abstract

Recent developments in optical tissue clearing have been difficult to apply for the morphometric analysis of organs with high cellular content and small functional structures, such as the kidney. Here, we establish combinations of genetic and immuno-labelling for single cell identification, tissue clearing and subsequent de-clarification for histoimmunopathology and transmission electron microscopy. Using advanced light microscopy and computational analyses, we investigated a murine model of crescentic nephritis, an inflammatory kidney disease typified by immune-mediated damage to glomeruli leading to the formation of hypercellular lesions and the rapid loss of kidney function induced by nephrotoxic serum. Results show a graded susceptibility of the glomeruli, significant podocyte loss and capillary injury. These effects are associated with activation of parietal epithelial cells and formation of glomerular lesions that may evolve and obstruct the kidney tubule, thereby explaining the loss of kidney function. Thus, our work provides new high-throughput endpoints for the analysis of complex tissues with single-cell resolution.Copyright © 2019 International Society of Nephrology

Published
2019

36. CX3CR1 is a gatekeeper for intestinal barrier integrity in mice: Limiting steatohepatitis by maintaining intestinal homeostasis.

Author

Schneider, K.M., Schneider, K.M., Bieghs, V., Heymann, F., Hu, W., Dreymueller, D., Liao, L., Frissen, M., Ludwig, A., Gassler, N., Pabst, O., Latz, E., Selige, G., Penders, J., Tacke, F., Trautwein, C., Schneider, K.M., Schneider, K.M., Bieghs, V., Heymann, F., Hu, W., Dreymueller, D., Liao, L., Frissen, M., Ludwig, A., Gassler, N., Pabst, O., Latz, E., Selige, G., Penders, J., Tacke, F., and Trautwein, C.

Abstract

Nonalcoholic fatty liver disease is seen as the hepatic manifestation of the metabolic syndrome and represents the most common liver disease in Western societies. The G protein-coupled chemokine receptor CX3CR1 plays a central role in several metabolic syndrome-related disease manifestations and is involved in maintaining intestinal homeostasis. Because diet-induced intestinal dysbiosis is a driver for nonalcoholic fatty liver disease, we hypothesized that CX3CR1 may influence the development of steatohepatitis. In two independent models of diet-induced steatohepatitis (high-fat diet and methionine/choline-deficient diet), CX3CR1 protected mice from excessive hepatic steatosis and inflammation, as well as systemic glucose intolerance. Lack of Cx3cr1 expression was associated with significantly altered intestinal microbiota composition, which was linked to an impaired intestinal barrier. Concomitantly, endotoxin levels in portal serum and inflammatory macrophages in liver were increased in Cx3cr1(-/-) mice, indicating an increased inflammatory response. Depletion of intestinal microbiota by administration of broad-spectrum antibiotics suppressed the number of infiltrating macrophages and promoted macrophage polarization in liver. Consequently, antibiotic-treated mice demonstrated a marked improvement of steatohepatitis. Conclusion: Microbiota-mediated activation of the innate immune responses through CX3CR1 is crucial for controlling steatohepatitis progression, which recognizes CX3CR1 as an essential gatekeeper in this scenario. (Hepatology 2015;62:1405-1416)

Published
2015

39. The transverse energy distribution in16O-nucleus collisions at 60 and 200 GeV per nucleon

Author

Åkesson, T., Almehed, S., Angelis, A. L. S., Armenise, N., Atherton, H., Aubry, P., Bartels, H. W., Bartley, J. H., Beaudoin, G., Beaulieu, J. M., Beker, H., Benary, O., Bettoni, D., Bisi, V., Blevis, I., Bøggild, H., Breskin, A., Chechik, R., Cleland, W., Clemen, M., Collick, B., Corriveau, F., Dagan, S., Dederichs, K., Dell'Uomo, S., Depommier, P., Devenish, R. C. E., Di Liberto, S., Di Giacomo, N., Dodd, J. R., Dolgoshein, B., Dress, A., En'yo, H., Erlandsson, B., Esten, M. J., Fabjan, C. W., Faessler, M., Fischer, P., Fraenkel, Z., Gaidot, A., Gavrilenko, I., Gibrat-Debu, F., Giubellino, P., Glässel, P., Goerlach, U., Haglund, R., Hamel, L. A., van Hecke, H., Hedberg, V., Heifetz, R., Heymann, F. F., Hölscher, A., Huber, S., Jacak, B., Jarslkog, G., Johansson, S., Kalinovski, A., Kantserov, A., Kraner, H., Kroh, V., Lamarche, F., Leroy, C., Lissauer, D., London, G., Lörstad, B., Lounis, A., Ludlam, T., Marzari-Chiesa, A., Masera, M., Mayburov, S., Mazzoni, M. A., McCubbin, M. L., McCubbin, N. A., McGaughey, P., Meddi, F., Mjörnmark, U., Muciaccia, M. T., Murray, M., Neubert, M., Nevski, P., Nilsson, S., Olsen, L., Oren, Y., Pansart, J. P., Park, Y. M., Pfeiffer, A., Piuz, F., Polychronakos, V., Poulard, G., Price, M., Rahm, D., Ramello, L., Riccati, L., Ries, H., Romano, G., Roosen, R., Rosa, G., Russ, J., Schukraft, J., Sekimoto, M., Sellden, B., Seman, M., Shmeleva, A., Shotton, P., Sidorov, V., Simone, S., Sirois, Y., Sletten, H., Smirnov, S., Soltani, J., Sondheim, W., Specht, H. J., Stumer, I., Sumarokov, A., Sunier, J., Tcherniatin, V., Thodberg, H. H., Thompson, J., Tikhomirov, V., Trent, P. T., Tserruya, I., Wigmans, R., Willis, W., and HELIOS Collaboration

Published
1988
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40. Transverse energy distributions in16O-nucleus collisions

Author

Corriveau, F., Åkesson, T., Almehed, S., Angelis, A. L. S., Armenise, N., Atherton, H., Aubry, P., Bartels, H. W., Bartley, J. H., Beaudoin, G., Beaulieu, J. M., Beker, H., Benary, O., Bettoni, D., Bisi, V., Blevis, I., Bøggild, H., Breskin, A., Chechik, R., Cleland, W., Clemen, M., Collick, B., Dagan, S., Dederichs, K., Dell'Uomo, S., Depommier, P., Devenish, R. C. E., DiLiberto, S., DiGiacomo, N., Dodd, J. R., Dolgoshein, B., Dress, A., En'yo, H., Erlandsson, B., Esten, M. J., Fabjan, C. W., Faessler, M., Fischer, P., Fraenkel, Z., Gaidot, A., Gavrilenko, I., Gibrat-Debu, F., Giubellino, P., Glässel, P., Goerlach, U., Haglund, R., Hamel, L. A., van Hecke, H., Hedberg, V., Heifetz, R., Heymann, F. F., Hölscher, A., Huber, S., Jacak, B., Jarlskog, G., Johansson, S., Kalinovski, A., Kantserov, A., Kramer, H., Kroh, V., Lamarche, F., Leroy, C., Lissauer, D., London, G., Lörstad, B., Lounis, A., Ludlam, T., Marzari-Chiesa, A., Masera, M., Mayburov, S., Mazzoni, M. A., McCubbin, M. L., McCubbin, N. A., McGaughey, P., Meddi, F., Mjörnmark, U., Muciaccia, M. T., Murray, M., Neubert, M., Nevski, P., Nilsson, S., Olsen, L., Oren, Y., Pansart, J. P., Park, Y. M., Pfeiffer, A., Piuz, F., Polychronakos, V., Poulard, G., Price, M., Rahm, D., Ramello, L., Riccati, L., Ries, H., Romano, G., Roosen, R., Rosa, G., Russ, J., Schukraft, J., Sekimoto, M., Sellden, B., Seman, M., Shmeleva, A., Shotton, P., Sidorov, V., Simone, S., Sirois, Y., Sletten, H., Smirnov, S., Soltani, J., Sondheim, W., Specht, H. J., Stumer, I., Sumarokov, A., Sunier, J., Tcherniatin, V., Thodberg, H. H., Thompson, J., Tikhomirov, V., Trent, P. T., Tserruya, I., Wigmans, R., Willis, W., and HELIOS Collaboration

Published
1988
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41. The holographic bubble chamber experiment and the determination of the effective charmed quark mass and theK-factor for hadronic charm production

Author

Cobbaert, H., Hobson, P. R., Arnold, R., Bailly, J. L., Balland, J. F., Barth, M., Bartley, J. H., Boratav, M., Bullock, F. W., Callichio, M., Coupland, M., Drevermann, H., Duff, B. G., Erriquez, O., Esten, M. J., Geiregat, D., Geissler, K., Grard, F., Henri, V. P., Herve, A., Heymann, F. F., Hrubec, J., Imrie, D. C., Johannsson, E., Kesteman, J., Lecoq, P., Lush, G. J., Maurer, G., Muciaccia, M. t., Natali, S., Nuzzo, S., Neuhofer, G., Olivier, P., Roosen, R., Ruggieri, F., Taurok, A., Tavernier, S. P. K., Touboul, M. C., Touchard, A. M., and Williams, O. R.

Published
1987
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45. Search for the Z+-baryon

Author

Bellamy, E. H., Buckley, T. F., March, P. V., Stefanini, A., Strong, J. A., Walker, R. N. F., Busza, W., Davis, D. G., Heymann, F. F., Nimmon, C. C., and Walton, D. T.

Published
1965
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49. Routing for analog chip designs at NXP Semiconductors

Author

van den Akker, J.M., Beelen, T., Bisseling, R.H., Fagginger Auer, B.O., von Heymann, F., Müller, T., Rommes, J., Planqué, Bob, Bhulai, Sandjai, Hulshof, Joost, Kager, Wouter, Rot, Thomas, Algorithmic Systems, Analyse, Analysis, Sub Algorithmic Systems begr. 01-01-2013, Sub Analysis begr. 01-01-2014, and Dep Wiskunde

Subjects
Landbouwwetenschappen, Wiskunde: algemeen, Wiskunde en computerwetenschappen, Wiskunde en Informatica (WIIN), Mathematics
Abstract

During the study week 2011 we worked on the question of how to automate certain aspects of the design of analog chips. Here we focused on the task of connecting different blocks with electrical wiring, which is particularly tedious to do by hand. For digital chips there is a wealth of research available for this, as in this situation the amount of blocks makes it hopeless to do the design by hand. Hence, we set our task to finding solutions that are based on the previous research, as well as being tailored to the specific setting given by NXP. This resulted in an heuristic approach, which we presented at the end of the week in the form of a protoype tool. In this report we give a detailed account of the ideas we used, and describe possibilities to extend the approach.

Published
2011

50. Orientation Effects in the X-ray Properties of High-z 3CRR Quasars

Author

Wilkes, Belinda J., Kuraszkiewicz, J., Haas, M., Antonucci, R., Ashby, M., Barthel, P., Birkinshaw, M., Chini, R., Fazio, G., Lawrence, C., Leipski, C., Ogle, P., Schulz, B., Willner, S., Heymann, F., Worrall, D., and Astronomy

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

A critical problem in understanding active galaxies is separation of intrinsic physical differences from observed differences due to orientation. Relativistic motion in powerful radio sources produces a significant level of anisotropic emission at all but the lowest frequencies. Obscuration is also anisotropic and strongly frequency-dependent. Combined, these two effects result in complex selection effects for observations in most wavebands, and there are few ways to select a sample that is sufficiently unbiased to test orientation effects as predicted by unification models. Low-frequency radio emission is one way to select an orientation-unbiased sample, albeit limited to the minority of AGN with strong radio emission. We report X-ray observations of a complete, flux-limited sample of 38 high-redshift 3CRR sources, 1

Published
2011

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