Gas and dust cooling along the major axis of M 33 (HerM33es). Herschel/PACS [C II] and [O I] observations

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Context. M 33 is a gas rich spiral galaxy of the Local Group. Its vicinity allows us to study its interstellar medium (ISM) on linear scales corresponding to the sizes of individual giant molecular clouds. Aims. We investigate the relationship between the two major gas cooling lines and the total infrared (TIR) dust continuum. Methods. We mapped the emission of gas and dust in M 33 using the far-infrared lines of [CII] and [OI](63 mu m) and the total infrared continuum. The line maps were observed with the PACS spectrometer on board the Herschel Space Observatory. These maps have 50 pc resolution and form a similar to 370 pc wide stripe along its major axis covering the sites of bright HII regions, but also more quiescent arm and inter-arm regions from the southern arm at 2 kpc galacto-centric distance to the south out to 5.7 kpc distance to the north. Full-galaxy maps of the continuum emission at 24 mu m from Spitzer/MIPS, and at 70 mu m, 100 mu m, and 160 mu m from Herschel/PACS were combined to obtain a map of the TIR. Results. TIR and [CII] intensities are correlated over more than two orders of magnitude. The range of TIR translates to a range of far ultraviolet (FUV) emission of G(0, obs)similar to 2 to 200 in units of the average Galactic radiation field. The binned [CII]/TIR ratio drops with rising TIR, with large, but decreasing scatter. The contribution of the cold neutral medium to the [CII] emission, as estimated from VLA HI data, is on average only 10%. Fits of modified black bodies to the continuum emission were used to estimate dust mass surface densities and total gas column densities. A correction for possible foreground absorption by cold gas was applied to the [OI] data before comparing it with models of photon dominated regions. Most of the ratios of [CII]/[OI] and ([CII]+[OI])/TIR are consistent with two model solutions. The median ratios are consistent with one solution at n similar to 2x10(2) cm(-3), G(0)similar to 60, and a second low-FUV solution at n similar to 10(4) cm(-3), G(0)similar to 1.5. Conclusions. The bulk of the gas along the lines-of-sight is represented by a low-density, high-FUV phase with low beam filling factors similar to 1. A fraction of the gas may, however, be represented by the second solution. © C. Kramer et al. 2020M.R. and S.V. acknowledge support by the research projects AYA2014-53506-P and AYA2017-84897-P from the Spanish Ministerio de Economia y Competitividad, from the European Regional Development Funds (FEDER) and the Junta de Andalucia (Spain) grants FQM108. This study has been partially financed by the Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR. FST thanks the Spanish Ministry of Economy and Competitiveness (MINECO) for support under grant number AYA2016-76219-P.Peer reviewe

Fatigue Stress Estimation for Submerged and Sub-Soil Welds of Offshore Wind Turbines on Monopiles Using Modal Expansion

The design of monopile foundations for offshore wind turbines is most often driven by fatigue. With the foundation price contributing to the total price of a turbine structure by more than 30%, wind farm operators seek to gain knowledge about the amount of consumed fatigue. Monitoring concepts are developed to uncover structural reserves coming from conservative designs in order to prolong the lifetime of a turbine. Amongst promising concepts is a wide array of methods using in-situ measurement data and extrapolating these results to desired locations below water surface and even seabed using models. The modal decomposition algorithm is used for this purpose. The algorithm obtains modal amplitudes from acceleration and strain measurements. In the subsequent expansion step these amplitudes are expanded to virtual measurements at arbitrary locations. The algorithm uses a reduced order model that can be obtained from either a FE model or measurements. In this work, operational modal analysis is applied to obtain the required stress and deflection shapes for optimal validation of the method. Furthermore, the measurements that are used as input for the algorithms are constrained to measurements from the dry part of the substructure. However, with subsoil measurement data available from a dedicated campaign, even validation for locations below mud-line is possible. After reconstructing strain history in arbitrary locations on the substructure, fatigue assessment over various environmental and operational conditions is carried out. The technique is found capable of estimating fatigue with high precision for locations above and below seabed

Wissenschafts- und Universitätsgeschichte | [Buchbesprechungen Nr. 525–530]

Guido Naschert (Hg.): Friedrich Christian Laukhard (1757-1822). Schriftsteller, Radikalaufklärer und gelehrter Soldat (Jürgen W. Schmidt)Franz Bosbach, John R. Davis, Karina Urbach (Hg.): Common Heritage. Documents and Sources relating to German-British Relations in the Archives and Collections of Windsor and Coburg. Vol. 1: The Archives. With an Appendix covering the State Archives in Gotha (Michael Fröhlich)Evelyn Brockhoff, Bernd Heidenreich, Michael Maaser (Hg.): Frankfurter Historiker (Hans-Christof Kraus)Simone König: Die Gedenkveranstaltungen zur Erinnerung an den Widerstand der Weißen Rose an der Ludwig-Maximilian-Universität München von 1945-1968 (Wolfgang Michalka)Bertrand Perz, Ina Markova (Hg.): 50 Jahre Institut für Zeitgeschichte der Universität Wien (1966-2016) (Martin Moll)Carole Fink: Writing 20th Century International History. Explorations and Examples (Markus Henkel

CD25(+) FoxP3(+) Memory CD4 T Cells Are Frequent Targets of HIV Infection In Vivo

Interleukin 2 (IL-2) signaling through the IL-2 receptor alpha chain (CD25) facilitates HIV replication in vitro and facilitates homeostatic proliferation of CD25+ FoxP3+ CD4+ T cells. CD25+ FoxP3+ CD4+ T cells may therefore constitute a suitable subset for HIV infection and plasma virion production. CD25+ FoxP3+ CD4+ T cell frequencies, absolute numbers, and the expression of CCR5 and cell cycle marker Ki67 were studied in peripheral blood from HIV+ and HIV− study volunteers. Different memory CD4+ T cell subsets were then sorted for quantification of cell-associated HIV DNA and phylogenetic analyses of the highly variable EnvV1V3 region in comparison to plasma-derived virus sequences. In HIV+ subjects, 51% (median) of CD25+ FoxP3+ CD4+ T cells expressed the HIV coreceptor CCR5. Very high frequencies of Ki67+ cells were detected in CD25+ FoxP3+ memory CD4+ T cells (median, 27.6%) in comparison to CD25− FoxP3− memory CD4+ T cells (median, 4.1%; P < 0.0001). HIV DNA content was 15-fold higher in CD25+ FoxP3+ memory CD4+ T cells than in CD25− FoxP3− T cells (P = 0.003). EnvV1V3 sequences derived from CD25+ FoxP3+ memory CD4+ T cells did not preferentially cluster with plasma-derived sequences. Quasi-identical cell-plasma sequence pairs were rare, and their proportion decreased with the estimated HIV infection duration. These data suggest that specific cellular characteristics of CD25+ FoxP3+ memory CD4+ T cells might facilitate efficient HIV infection in vivo and passage of HIV DNA to cell progeny in the absence of active viral replication. The contribution of this cell population to plasma virion production remains unclear