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922 results on '"Koenig, T."'

3. An active transverse energy filter to differentiate low energy particles with large pitch angles in a strong magnetic field

Author

Gauda, K., Schneidewind, S., Drexlin, G., Fulst, A., Hannen, V., König, T., Lokhov, A., Oelpmann, P., Ortjohann, H. -W., Pernice, W., Robertson, R. G. H., Salomon, R. W. J., Stappers, M., and Weinheimer, C.

Subjects
Physics - Instrumentation and Detectors
Abstract

We present the idea and proof of principle measurements for an angular-selective active filter for charged particles. The motivation for the setup arises from the need to distinguish background electrons from signal electrons in a spectrometer of MAC-E filter type. While a large fraction of the background electrons exhibit predominantly small angles relative to the magnetic guiding field (corresponding to a low amount of kinetic energy in the motion component transverse to the field lines, in the following referred to as transverse energy) and pass the filter mostly unhindered, signal electrons from an isotropically emitting source interact with the active filter and are detected. The concept is demonstrated using a microchannel plate (MCP) as an active filter element. When correctly aligned with the magnetic field, electrons with a small transverse energy pass the channels of the MCP without interaction while electrons with large transverse energies hit the channel walls and trigger an avalanche of secondary electrons that is subsequently detected. Due to several drawbacks of MCPs for an actual transverse energy filter, an alternative detection technique using microstructured Si-PIN diodes is proposed., Comment: 9 pages, 7 figures

Published
2022
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12. Real-time phase-shift detection of the surface plasmon resonance

Author

König, T., Weidemüller, M., and Hemmerich, A.

Subjects
Physics - Optics
Abstract

We investigate a method to directly measure the phase of a laser beam reflected from a metallic film after excitation of surface plasmon polaritons. This method permits real time access to the phase information, it increases the possible speed of data acquisition, and it may thus prove useful for increasing the sensitivity of surface plasmon based sensors.

Published
2010
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13. Auditory closed-loop modulation of slow wave sleep to treat major depressive disorder

Author

Fehér, K.D., primary, Henckaerts, P., additional, Omlin, X., additional, Tarokh, L., additional, Schneider, C.L., additional, Morishima, Y., additional, Züst, M.A., additional, Wunderlin, M., additional, Koenig, T., additional, Hertenstein, E., additional, Trinca, E., additional, Ellenberger, B., additional, Ruch, S., additional, Schmidig, F., additional, Mikutta, C., additional, Senn, W., additional, Klöppel, S., additional, and Nissen, C., additional

Published
2024
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16. THE CONVECTIVE TRANSPORT OF ACTIVE SPECIES IN THE TROPICS (CONTRAST) EXPERIMENT

Author

Pan, L. L., Atlas, E. L., Salawitch, R. J., Honomichl, S. B., Bresch, J. F., Randel, W. J., Apel, E. C., Hornbrook, R. S., Weinheimer, A. J., Anderson, D. C., Andrews, S. J., Baidar, S., Beaton, S. P., Campos, T. L., Carpenter, L. J., Chen, D., Dix, B., Donets, V., Hall, S. R., Hanisco, T. F., Homeyer, C. R., Huey, L. G., Jensen, J. B., Kaser, L., Kinnison, D. E., Koenig, T. K., Lamarque, J.-F., Liu, C., Luo, J., Luo, Z. J., Montzka, D. D., Nicely, J. M., Pierce, R. B., Riemer, D. D., Robinson, T., Romashkin, P., Saiz-Lopez, A., Schauffler, S., Shieh, O., Stell, M. H., Ullmann, K., Vaughan, G., Volkamer, R., and Wolfe, G.

Published
2017

29. Selective slow-wave sleep suppression through auditory closed-loop stimulation

Author

Fehér, K.D., primary, Omlin, X., additional, Tarokh, L., additional, Schneider, C., additional, Morishima, Y., additional, Züst, M., additional, Wunderlin, M., additional, Koenig, T., additional, Hertenstein, E., additional, Trinka, E., additional, Ellenberger, B., additional, Ruch, S., additional, Schmidig, F., additional, Mikutta, C., additional, Senn, W., additional, Klöppel, S., additional, and Nissen, C., additional

Published
2022
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41. Hypertensive disorders in women with peripartum cardiomyopathy: insights from the ESC EORP PPCM Registry

Author

Jackson, Alice M., Petrie, Mark C., Frogoudaki, Alexandra, Laroche, Cécile, Gustafsson, Finn, Ibrahim, Bassem, Mebazaa, Alexandre, Johnson, Mark R., Seferovic, Petar M., Regitz‐Zagrosek, Vera, Mbakwem, Amam, Böhm, Michael, Prameswari, Hawani Sasmaya, Abdel Gawad, Doaa Ahmed Fouad, Goland, Sorel, Damasceno, Albertino, Karaye, Kamilu, Farhan, Hasan Ali, Hamdan, Righab, Maggioni, Aldo P., Sliwa, Karen, Bauersachs, Johann, Meer, Peter, Favaloro, R., Favaloro, L., Carballo, M., Peradejordi, M., Renedo, M.F., Absi, D., Bertolotti, A., Ratto, R., Talavera, M.L., Gomez, R., Lockwood, S., Barton, T., Austin, M‐A., Arstall, M., Aldridge, E., Chow, Y.Y., Dekker, G., Mahadavan, G., Rose, J., Wittwer, M., Hoppe, U., Sandhofer, A., Bahshaliyev, A., Gasimov, Z., Babayev, A., Niftiyev, P., Hasanova, I., AlBannay, R., AlHaiki, W., Husain, A., Mahdi, N., Kurlianskaya, A., Lukyanchyk, M., Shatova, O., Troyanova‐Shchutskaia, T., Anghel, L., De Pauw, M., Gevaert, S., De Backer, J., De Hosson, M., Vervaet, P., Timmermans, P.J., Janssen, A., Yameogo, N.V., Kagambega, L.J., Cumyn, A., Caron, N., Cote, A‐M., Sauve, N., Nkulu, D. Ngoy, Lez, D. Malamba, Yolola, E. Ngoy, Krejci, J., Poloczkova, H., Ersboll, A., Gustafsson, F., Elrakshy, Y., Hassanein, M., Hammad, B., Eldin, O. Nour, Fouad, D., Salman, S., Zareh, Z., Abdeall, D., Elenin, H. Abo, Ebaid, H., El Nagar, A., Farag, S., Saed, M., El Rahman, Y H Abd, Ibrahim, B.S., Abdelhamid, M., Hanna, R.N. W., Youssef, G., Awad, R., Botrous, O.L. I., Halawa, S. Ibrahim, Nasr, G., Saad, A., El Tahlawi, M., Abdelbaset, M., El‐saadawy, M., El‐shorbagy, A., Shalaby, G., Anttonen, O., Tolppanen, H., Hamekoski, S., Menez, T., Noel, A., Lamblin, N., Mouquet, F., Coulon, C., Groote, P., Langlois, S., Schurtz, G., Cohen‐Solal, A., Mebazaa, A., Fournier, M‐C., Louadah, B., Akrout, N., Logeart, D., Leurent, G., Jovanova, S., Arnaudova‐Dezulovicj, F., Livrinova, V., Bauersachs, J., Hilfiker‐Kleiner, D., Berliner, D., Jungesblut, M., Koenig, T., Moulig, V.A., Pfeffer, T.J., Böhm, M., Kindermann, I., Schwarz, V., Schmitt, C., Swojanowsky, P., Pettit, S., Petrie, M., McAdam, M., Patton, D., Bakhai, A., Krishnamurthy, V., Lim, L., Clifford, P., Bowers, N., Clark, A. L., Witte, K., Cullington, D., Oliver, J., Simms, A., Mcginlay, M., McDonagh, T., Shah, A. M., Amin‐Youssef, G., De Courcey, J., Martin, K., Shaw, S., Vause, S., Wallace, S., Malin, G., Wick, C., Nikolaou, M., Rentoukas, I., Chinchilla, H., Andino, L., Iyengar, S., Chandra, S., Yadav, D.K., Babu, R. Ravi, Singh, A.K., Kumar, S., Karunamay, B.B., Chaubey, S.K., Dhiman, S.R., Jha, V.C., Singh, S.K., Kodati, D., Dasari, R., Sultana, S., Dewi, T.I., Prameswari, H. Sasmaya, Al‐Farhan, H.A., Al‐Hussein, A., Yaseen, I.F., Al‐Azzawi, Falah, Al‐Saedi, Ghazi, Mahmood, G.M., Mohammed, M.K., Ridha, A.F., Shotan, A., Vazan, A., Goland, S., Biener, M., Senni, M., Grosu, A., Martin, E., Esposti, D. Degli, Bacchelli, S., Borghi, C., Metra, M., Sciatti, E., Orabona, R., Sani, F., Brunetti, N.D., Sinagra, G., Bobbo, M., D'Agata Mottolese, B., Gesuete, V., Rakar, S., Ramani, F., Kamiya, C., Barasa, A., Ngunga, M., Bajraktari, G., Hyseni, V., Lleshi, D., Pllana, E., Pllana, T., Noruzbaeva, A., Ismailov, F., Mirrakhimov, E., Abilova, S., Lunegova, O., Kerimkulova, A., Osmankulova, G., Duishenalieva, M., Kurmanbekova, B., Turgunov, M., Mamasaidova, S., Bektasheva, E., Kavoliuniene, A., Muckiene, G., Vaitiekiene, A., Celutkiene, J., Balkevicine, L., Barysiene, J., Chee, K.H., Damasceno, A., Machava, M., Veldhuisen, D.J., Meer, P., Berg, M., Roos‐Hesselink, J., Hagen, I., Baris, L., Hurtado, P., Ezeonu, P., Isiguzo, G., Obeka, N., Onoh, R., Asogwa, F., Onyema, C., Otti, K., Ojji, D., Odili, A., Nwankwo, A., Karaye, K., Ishaq, N., Sanni, B., Abubakar, H., Mohammed, B., Sani, M., Kehinde, M., Mbakwem, A., Afolabi, B., Amadi, C., Kilasho, M., Qamar, N., Furnaz, S., Gurmani, S., Kayani, M.G.A. Mahmood, Munir, R., Hussain, S., Malik, S., Mumtaz, S., Saligan, J.R., Rubis, P., Biernacka‐Fijalkowska, B., Lesniak‐Sobelga, A., Wisniowska‐Smialek, S., Kasprzak, J.D., Lelonek, M., Zycinski, P., Jankowski, L., Grajek, S., Oko‐Sarnowska, Z., Rutkowska, A. Bartczak, Kaluzna‐Oleksy, M., Plaskota, K., Demkow, M., Dzielinska, Z., Henzel, J., Kryczka, K., Moiseeva, O., Irtyuga, O., Karelkina, E., Zazerskaya, I., Seferovic, P.M., Milinkovic, I., Živkovic, I., Ristic, A.D., Milasinovic, D., Kong, W. KF, Tan, L.K., Tan, J.L., Thain, S., Poh, K.K., Yip, J., Sliwa, K., Azibani, F., Hovelmann, J., Viljoen, C., Briton, O., Zamora, E., Orcajo, N. Alonso, Carbonell, R., Pascual, C., Muncharaz, J. Farre, Alonso‐Pulpon, L., Cubero, J. Segovia, Urquia, M. Taibo, Garcia‐Pavia, P., Gomez‐Bueno, M., Cobo‐Marcos, M., Briceno, A., Galvan, E. De Teresa, Garcia‐Pinilla, J.M., Robles‐Mezcua, A., Morcillo‐Hildalgo, L., Elbushi, A., Suliman, A., Ahamed, N., Jazzar, K., Murtada, M., Schaufelberger, M., Goloskokova, V., Hullin, R., Yarol, N., Arrigo, M., Cavusoglu, Y., Eraslan, S., Fak, A.S., Enar, S. Catirli, Sarac, L., Cankurtaran, B., Gumrukcuoglu, H., Ozturk, F., Omagino, J., Mondo, C., Lwabi, P., Ingabire, P., Nabbaale, J., Nyakoojo, W., Okello, E., Sebatta, E., Ssinabulya, I., Atukunda, E., Kitooleko, S., Semu, T., Salih, B.T., Komaranchath, A.M., Almahmeed, W.A.R., Gerges, F., Farook, F.S. Mohamed, Albakshy, F., Mahmood, N., Wani, S., Freudenberger, R., Islam, N., Quinones, J., Sundlof, D., Beitler, C., Centolanza, L., Cornell, K., Huffaker, S., Matos, L., Marzo, K., Paruchuri, V., Patel, D., Abdullaev, T., Alyavi, B., Mirzarakhimova, S., Tsoy, I., Bekbulatova, R., and Uzokov, J.

Abstract

Aims: \ud Hypertensive disorders occur in women with peripartum cardiomyopathy (PPCM). How often hypertensive disorders co-exist, and to what extent they impact outcomes, is less clear. We describe differences in phenotype and outcomes in women with PPCM with and without hypertensive disorders during pregnancy.\ud \ud Methods: \ud The European Society of Cardiology PPCM Registry enrolled women with PPCM from 2012-2018. Three groups were examined: 1) women without hypertension (‘PPCM-noHTN’); 2) women with hypertension but without pre-eclampsia (‘PPCM-HTN’); 3) women with pre-eclampsia (‘PPCM-PE’). Maternal (6-month) and neonatal outcomes were compared.\ud \ud Results: \ud Of 735 women included, 452 (61.5%) had PPCM-noHTN, 99 (13.5%) had PPCM-HTN and 184 (25.0%) had PPCM-PE. Compared to women with PPCM-noHTN, women with PPCM-PE had more severe symptoms (NYHA IV in 44.4% and 29.9%, p

Published
2021

43. Aircraft Measurements of BrO, IO, Glyoxal, NO2, H2O, O2-O2 and Aerosol Extinction Profiles in the Tropics: Comparison with Aircraft-/Ship-Based in Situ and Lidar Measurements

Author

Volkamer, R, Baidar, S, Campos, T. L, Coburn, S, DiGangi, J. P, Dix, B, Eloranta, E. W, Koenig, T. K, Morley, B, Ortega, I, Pierce, B. R, Reeves, M, Sinreich, R, Wang, S, Zondlo, M. A, and Romashkin, P. A

Subjects
Geophysics
Abstract

Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4/ were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAXDOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/ National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity-enhanced DOAS and MAX-DOAS. Inside the marine boundary layer (MBL) no BrO was detected (smaller than 0.5 pptv), and 0.2-0.55 pptv IO and 32-36 pptv glyoxal were observed. The near-surface concentrations agree within 30% (IO) and 10% (glyoxal) between ship and air-craft. The BrO concentration strongly increased with altitude to 3.0 pptv at 14.5 km (RF12, 9.1 to 8.6 deg N; 101.2 to 97.4 deg W). At 14.5 km, 5-10 pptv NO2 agree with model predictions and demonstrate good control over separating tropospheric from stratospheric absorbers (NO2 and BrO). Our profile retrievals have 12-20 degrees of freedom (DoF) and up to 500m vertical resolution. The tropospheric BrO vertical column density (VCD) was 1.5 x 10(exp 13) molec cm(exp -2) (RF12) and at least 0.5 x 10(exp 13) molec cm(exp -2) (RF17, 0- 10 km, lower limit). Tropospheric IO VCDs correspond to 2.1 x 10(exp 12) molec cm(exp -2) (RF12) and 2.5 x 10(exp 12) molec cm(exp -2) (RF17) and glyoxal VCDs of 2.6 x 10(exp 14) molec cm(exp -2) (RF12) and 2.7 x 10(exp 14) molec cm(exp -2) (RF17). Surprisingly, essentially all BrO as well as the dominant IO and glyoxal VCD fraction was located above 2 km (IO: 58 plus or minus 5 %, 0.1-0.2 pptv; glyoxal: 52 plus or minus 5 %, 3-20 pptv). To our knowledge there are no previous vertically resolved measurements of BrO and glyoxal from aircraft in the tropical free troposphere. The atmospheric implications are briefly discussed. Future studies are necessary to better understand the sources and impacts of free tropospheric halogens and oxygenated hydrocarbons on tropospheric ozone, aerosols, mercury oxidation and the oxidation capacity of the atmosphere.

Published
2015
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48. The Impact of COVID-19 on the Path to Climate Neutral Air Transport - An Empirical Investigation

Author

Ringbeck J and Koenig T

Subjects
Finance, Aviation, business.industry, Bankruptcy, Path (graph theory), Equity (finance), Climate change, Preprint, Air traffic control, business, China
Abstract

The COVID-19 crisis still has a firm grip on the aviation industry after global air traffic slumped to 66% below the previous year's level in 2020, and many airlines could only be saved from bankruptcy by special loans or direct state equity investments. At the same time, there is increasing pressure on airlines to accelerate the decarbonization of the sector. Recently, many countries, such as China, the EU, and the US have significantly tightened their climate targets. Air travel is considered a particularly damaging form of travel since before Greta Thunberg's "Friday for Future" movement. As a result, aviation will be expected to make a stronger contribution to decarbonization going forward. The question is how air transport, which has been badly hit by the COVID-19 pandemic, can succeed in converting to climate-neutral flying. An international survey conducted in the fall of 2020 with more than 220 aviation experts and senior managers provides interesting insights and concrete advice on how a path to climate-neutral air transport can be designed and which new risks need to be considered in particular on this path.

Published
2021
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50. Intercomparison of NO₂, O₄, O₃ and HCHO slant column measurements by MAX-DOAS and zenith-sky UV--visible spectrometers during CINDI-2

Author

Kreher, K., Van Roozendael, M., Hendrick, F., Apituley, A., Dimitropoulou, E., Frieß, U., Richter, A., Wagner, T., Lampel, J., Abuhassan, N., Ang, L., Anguas, M., Bais, A., Benavent, N., Bösch, T., Bognar, K., Borovski, A., Bruchkouski, I., Cede, A., Chan, Ka Lok, Donner, S., Drosoglou, T., Fayt, C., Finkenzeller, H., Garcia-Nieto, D., Gielen, C., Gómez-Martin, L., Hao, N., Henzing, B., Herman, J. R., Hermans, C., Hoque, S., Irie, H., Jin, J., Johnston, P., Khayyam Butt, J., Khokhar, F., Koenig, T. K., Kuhn, J., Kumar, V., Liu, C., Ma, J., Merlaud, A., Mishra, A. K., Müller, M., Navarro-Comas, M., Ostendorf, M., Pazmino, A., Peters, E., Pinardi, G., Pinharanda, M., Piters, A., Platt, U., Postylyakov, O., Prados-Roman, C., Puentedura, O., Querel, R., Saiz-Lopez, A., Schönhardt, A., Schreier, S. F., Seyler, A., Sinha, V., Spinei, E., Strong, K., Tack, F., Tian, X., Tiefengraber, M., Tirpitz, J.-L., van Gent, J., Volkamer, R., Vrekoussis, M., Wang, S., Wang, Zhuoru, Wenig, M., Wittrock, F., Xie, P. H., Xu, J., Yela, M., Zhang, C., and Zhao, X.

Subjects
remote sensing, trace gas, MAX-DOAS, Atmosphärenprozessoren, inter-comparison
Abstract

In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants for a period of 17 d during the Second Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI-2) that took place at Cabauw, the Netherlands (51.97∘ N, 4.93∘ E). We report on the outcome of the formal semi-blind intercomparison exercise, which was held under the umbrella of the Network for the Detection of Atmospheric Composition Change (NDACC) and the European Space Agency (ESA). The three major goals of CINDI-2 were (1) to characterise and better understand the differences between a large number of multi-axis differential optical absorption spectroscopy (MAX-DOAS) and zenith-sky DOAS instruments and analysis methods, (2) to define a robust methodology for performance assessment of all participating instruments, and (3) to contribute to a harmonisation of the measurement settings and retrieval methods. This, in turn, creates the capability to produce consistent high-quality ground-based data sets, which are an essential requirement to generate reliable long-term measurement time series suitable for trend analysis and satellite data validation. The data products investigated during the semi-blind intercomparison are slant columns of nitrogen dioxide (NO2), the oxygen collision complex (O4) and ozone (O3) measured in the UV and visible wavelength region, formaldehyde (HCHO) in the UV spectral region, and NO2 in an additional (smaller) wavelength range in the visible region. The campaign design and implementation processes are discussed in detail including the measurement protocol, calibration procedures and slant column retrieval settings. Strong emphasis was put on the careful alignment and synchronisation of the measurement systems, resulting in a unique set of measurements made under highly comparable air mass conditions. The CINDI-2 data sets were investigated using a regression analysis of the slant columns measured by each instrument and for each of the target data products. The slope and intercept of the regression analysis respectively quantify the mean systematic bias and offset of the individual data sets against the selected reference (which is obtained from the median of either all data sets or a subset), and the rms error provides an estimate of the measurement noise or dispersion. These three criteria are examined and for each of the parameters and each of the data products, performance thresholds are set and applied to all the measurements. The approach presented here has been developed based on heritage from previous intercomparison exercises. It introduces a quantitative assessment of the consistency between all the participating instruments for the MAX-DOAS and zenith-sky DOAS techniques.

Published
2020

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