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1. Abundant molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko

Author

Bieler, A., Altwegg, K., Balsiger, H., Bar-Nun, A., Berthelier, J.-J., Bochsler, P., Briois, C., Calmonte, U., Combi, M., De Keyser, J., van Dishoeck, E.F., Fiethe, B., Fuselier, S.A., Gasc, S., Gombosi, T.I., Hansen, K.C., Hassig, M., Jackel, A., Kopp, E., Korth, A., Roy, L. Le, Mall, U., Maggiolo, R., Marty, B., Mousis, O., Owen, T., Reme, H., Rubin, M., Semon, T., Tzou, C.-Y., Waite, J.H., Walsh, C., and Wurz, P.

Subjects
Comets -- Chemical properties -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The composition of the neutral gas comas of most comets is dominated by [H.sub.2]O, CO and C[O.sub.2], typically comprising as much as 95 per cent of the total gas density (1). In addition, cometary comas have been found to contain a rich array of other molecules, including sulfuric compounds and complex hydrocarbons. Molecular oxygen ([O.sub.2]), however, despite its detection on other icy bodies such as the moons of Jupiter and Saturn (2,3), has remained undetected in cometary comas. Here we report in situ measurement of [O.sub.2] in the coma of comet 67P/Churyumov-Gerasimenko, with local abundances ranging from one per cent to ten per cent relative to [H.sub.2]O and with a mean value of 3.80 ± 0.85 per cent. Our observations indicate that the [O.sub.2]/[H.sub.2]O ratio is isotropic in the coma and does not change systematically with heliocentric distance. This suggests that primordial [O.sub.2] was incorporated into the nucleus during the comet's formation, which is unexpected given the low upper limits from remote sensing observations (4). Current Solar System formation models do not predict conditions that would allow this to occur., Measurements of the coma of 67P/Churyumov-Gerasimenko (hereafter 67P) were made between September 2014 and March 2015 with the ROSINA-DFMS mass spectrometer (5) on board the Rosetta spacecraft. For the present [...]

Published
2015

3. Ion composition at comet 67P near perihelion : Rosetta observations and model-based interpretation

Author

Heritier, K. L., Altwegg, K., Balsiger, H., Berthelier, J. -J, Beth, A., Bieler, A., Biver, N., Calmonte, U., Combi, M. R., De Keyser, J., Eriksson, Anders I., Fiethe, B., Fougere, N., Fuselier, S. A., Galand, M., Gasc, S., Gombosi, T. I., Hansen, K. C., Hassig, M., Kopp, E., Odelstad, Elias, Rubin, M., Tzou, C. -Y, Vigren, Erik, Vuitton, V., Heritier, K. L., Altwegg, K., Balsiger, H., Berthelier, J. -J, Beth, A., Bieler, A., Biver, N., Calmonte, U., Combi, M. R., De Keyser, J., Eriksson, Anders I., Fiethe, B., Fougere, N., Fuselier, S. A., Galand, M., Gasc, S., Gombosi, T. I., Hansen, K. C., Hassig, M., Kopp, E., Odelstad, Elias, Rubin, M., Tzou, C. -Y, Vigren, Erik, and Vuitton, V.

Abstract

We present the ion composition in the coma of comet 67P with newly detected ion species over the 28-37 u mass range, probed by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Double Focusing Mass Spectrometer (DFMS). In summer 2015, the nucleus reached its highest outgassing rate and ion-neutral reactions started to take place at low cometocentric distances. Minor neutrals can efficiently capture protons from the ion population, making the protonated version of these neutrals a major ion species. So far, only NH4+ has been reported at comet 67P. However, there are additional neutral species with proton affinities higher than that of water (besides NH3) that have been detected in the coma of comet 67P: CH3OH, HCN, H2CO and H2S. Their protonated versions have all been detected. Statistics showing the number of detections with respect to the number of scans are presented. The effect of the negative spacecraft potential probed by the Rosetta Plasma Consortium/LAngmuir Probe on ion detection is assessed. An ionospheric model has been developed to assess the different ion density profiles and compare them to the ROSINA/DFMS measurements. It is also used to interpret the ROSINA/DFMS observations when different ion species have similar masses, and their respective densities are not high enough to disentangle them using the ROSINA/DFMS high-resolution mode. The different ion species that have been reported in the coma of 67P are summarized and compared with the ions detected at comet 1P/Halley during the Giotto mission.

Published
2017
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4. Ion composition at comet 67P near perihelion: Rosetta observations and model-based interpretation

Author

Heritier, K. L., primary, Altwegg, K., additional, Balsiger, H., additional, Berthelier, J.-J., additional, Beth, A., additional, Bieler, A., additional, Biver, N., additional, Calmonte, U., additional, Combi, M. R., additional, De Keyser, J., additional, Eriksson, A. I., additional, Fiethe, B., additional, Fougere, N., additional, Fuselier, S. A., additional, Galand, M., additional, Gasc, S., additional, Gombosi, T. I., additional, Hansen, K. C., additional, Hassig, M., additional, Kopp, E., additional, Odelstad, E., additional, Rubin, M., additional, Tzou, C.-Y., additional, Vigren, E., additional, and Vuitton, V., additional

Published
2017
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5. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
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6. First in situ detection of the cometary ammonium ion NH4+ (protonated ammonia NH3) in the coma of 67P/C-G near perihelion

Author

Beth, A., Altwegg, K., Balsiger, H., Berthelier, J. -J, Calmonte, U., Combi, M. R., De Keyser, J., Dhooghe, F., Fiethe, B., Fuselier, S. A., Galand, M., Gasc, S., Gombosi, T. I., Hansen, K. C., Hassig, M., Heritier, K. L., Kopp, E., Le Roy, L., Mandt, K. E., Peroy, S., Rubin, M., Semon, T., Tzou, C. -Y, Vigren, Erik, Beth, A., Altwegg, K., Balsiger, H., Berthelier, J. -J, Calmonte, U., Combi, M. R., De Keyser, J., Dhooghe, F., Fiethe, B., Fuselier, S. A., Galand, M., Gasc, S., Gombosi, T. I., Hansen, K. C., Hassig, M., Heritier, K. L., Kopp, E., Le Roy, L., Mandt, K. E., Peroy, S., Rubin, M., Semon, T., Tzou, C. -Y, and Vigren, Erik

Abstract

In this paper, we report the first in situ detection of the ammonium ion NH4+ at 67P/Churyumov-Gerasimenko (67P/C-G) in a cometary coma, using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Double Focusing Mass Spectrometer (DFMS). Unlike neutral and ion spectrometers onboard previous cometary missions, the ROSINA/DFMS spectrometer, when operated in ion mode, offers the capability to distinguish NH4+ from H2O+ in a cometary coma. We present here the ion data analysis of mass-to-charge ratios 18 and 19 at high spectral resolution and compare the results with an ionospheric model to put these results into context. The model confirms that the ammonium ion NH4+ is one of the most abundant ion species, as predicted, in the coma near perihelion.

Published
2016
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7. Photochemistry of O(1D) and O(1S) lines in the coma of 67P/Churyumov-Gerasimenko

Author

European Geosciences Union (EGU) General Assembly 2016 (April 17-22, 2016: Vienna, Austria), Cessateur, G., De Keyser, J, Maggiolo, Romain, Gibbons, Andrew, Gronoff, G., Gunell, H., Dhooghe, F., Loreau, Jérôme, Vaeck, Nathalie, Altwegg, K., Bieler, A., Briois, C., Calmonte, U., Combi, M. R., Fiethe, B., Fuselier, S. A., Gombosi, T. I., Hassig, M., Le Roy, L., Neefs, E., Rubin, M., Sémon, T., European Geosciences Union (EGU) General Assembly 2016 (April 17-22, 2016: Vienna, Austria), Cessateur, G., De Keyser, J, Maggiolo, Romain, Gibbons, Andrew, Gronoff, G., Gunell, H., Dhooghe, F., Loreau, Jérôme, Vaeck, Nathalie, Altwegg, K., Bieler, A., Briois, C., Calmonte, U., Combi, M. R., Fiethe, B., Fuselier, S. A., Gombosi, T. I., Hassig, M., Le Roy, L., Neefs, E., Rubin, M., and Sémon, T.

Abstract

info:eu-repo/semantics/nonPublished

Published
2016

8. Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko

Author

Cessateur, G., De Keyser, Johan, Maggiolo, Romain, Gibbons, Andrew, Gronoff, G., Gunell, H., Dhooghe, F., Loreau, Jérôme, Vaeck, Nathalie, Altwegg, K., Bieler, A., Briois, C., Calmonte, U., Combi, M. R., Fiethe, B., Fuselier, S. A., Gombosi, T. I., Hassig, M., Le Roy, L., Neefs, E., Rubin, M., Sémon, T., Cessateur, G., De Keyser, Johan, Maggiolo, Romain, Gibbons, Andrew, Gronoff, G., Gunell, H., Dhooghe, F., Loreau, Jérôme, Vaeck, Nathalie, Altwegg, K., Bieler, A., Briois, C., Calmonte, U., Combi, M. R., Fiethe, B., Fuselier, S. A., Gombosi, T. I., Hassig, M., Le Roy, L., Neefs, E., Rubin, M., and Sémon, T.

Abstract

Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water 3.80 ± 0.85 within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P, with a relative error of about 25%. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. Indeed, there is no compelling reason why O2 would not be a common cometary volatile, making revision of earlier assessments regarding the CO2 abundance in cometary atmospheres necessary. The large uncertainties of the CO2 photodissociation cross section imply that more studies are required in order to better constrain the O(1S) and O(1D) production through this mechanism. Space weather phenomena, such as powerful solar flares, could be used as tools for doing so, providing additional information on a good estimation of the O2 abundance within cometary atmospheres., FLWOA, info:eu-repo/semantics/published

Published
2016

9. Halogens at Comet 67P/Churyumov-Gerasimenko seen with ROSINA-DFMS

Author

AGU Fall Meeting (2015-12), Dhooghe, F., Cessateur, G., Altwegg, K., Berthelier, J.-J., Briois, C., Calmonte, U., Combi, M. R., De Keyser, J, Equeter, Eddy, Fiethe, B., Fuselier, S. A., Gibbons, Andrew, Gombosi, T. I., Gunell, H., Hassig, M., Le Roy, L., Maggiolo, Romain, Mall, Urs, Marty, Bernard, Neefs, Eddy, Rubin, M., Sémon, T., AGU Fall Meeting (2015-12), Dhooghe, F., Cessateur, G., Altwegg, K., Berthelier, J.-J., Briois, C., Calmonte, U., Combi, M. R., De Keyser, J, Equeter, Eddy, Fiethe, B., Fuselier, S. A., Gibbons, Andrew, Gombosi, T. I., Gunell, H., Hassig, M., Le Roy, L., Maggiolo, Romain, Mall, Urs, Marty, Bernard, Neefs, Eddy, Rubin, M., and Sémon, T.

Abstract

The Rosetta spacecraft has been studying the coma of comet 67P/Churyumov-Gerasimenko since August 2014 and will continue to do so up to the comet’s perihelion and for part of the voyage of the comet away from the Sun. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) sensor DFMS is a double focussing mass spectrometer with a mass range 13–140 u/e. It is optimized for high mass resolution and large dynamic range and is an invaluable tool for the characterization of neutrals in the coma (1). Hydrogen fluoride (HF) and hydrogen chloride (HCl) are expected to be the main reservoirs of fluorine and chlorine wherever hydrogen is predominantly molecular in the interstellar medium (2). The strong depletion of these compounds in dense molecular clouds suggests freeze-out of these compounds onto grains in cold environments (3, 4). Therefore, one can expect that HCl and HF were also incorporated into comets. The halogens HF, HCl and also HBr (hydrogen bromide) have been measured using ROSINA-DFMS and this contribution will focus on the presence, abundance and variability of halogens in the coma of comet 67P. These results may provide insights on the halogen chemistry in the early solar nebula. (1) Balsiger et al. Space Science Reviews 128, 745. (2) Neufeld & Wolfire, ApJ 706, 1594. (3) Peng et al. ApJ 723, 218. (4) Emprechtinger et al. ApJ 756, 136., info:eu-repo/semantics/nonPublished

Published
2015

10. Atomic oxygen green and red emissions in the comet 67P/Churyumov-Gerasimenko

Author

AGU Fall Meeting (2015), Cessateur, G., Altwegg, K., Berthelier, J.-J., Briois, C., Calmonte, U., Combi, M. R., Dhooghe, F., De Keyser, J, Equeter, Eddy, Fiethe, B., Fuselier, S. A., Gibbons, Andrew, Gombosi, T. I., Hassig, M., Gunell, H., Le Roy, L., Mall, Urs, Marty, Bernard, Maggiolo, Romain, Neefs, Eddy, Rubin, M., Sémon, T., AGU Fall Meeting (2015), Cessateur, G., Altwegg, K., Berthelier, J.-J., Briois, C., Calmonte, U., Combi, M. R., Dhooghe, F., De Keyser, J, Equeter, Eddy, Fiethe, B., Fuselier, S. A., Gibbons, Andrew, Gombosi, T. I., Hassig, M., Gunell, H., Le Roy, L., Mall, Urs, Marty, Bernard, Maggiolo, Romain, Neefs, Eddy, Rubin, M., and Sémon, T.

Abstract

info:eu-repo/semantics/nonPublished

Published
2015

12. From seafloor spreading to obduction: Jurassic–Cretaceous evolution of the northern branch of the Neotethys in the Northeastern Anatolian and Lesser Caucasus regions

Author

Hassig, M., Rolland, Y., and Sosson, M.

Abstract

We present arguments for an innovative tectonic set-up just prior to the Northern Neotethys obduction event in the NE Anatolian and Lesser Caucasus area. Along the Northern Neotethyan suture (the Ankara–Erzincan–Amasia–Sevan–Akera suture zone), relicts of the northern branch of the Neotethys oceanic domain outcrop as preserved unmetamorphosed slivers obducted over the northern edge of the South Armenian Block (SAB) and Taurides–Anatolides Platform (TAP) margins. Recent studies have shown that the ophiolitic bodies are formed of similar lithologies of Middle Jurassic age, all bearing mid-ocean ridge basalt chemical compositions enriched in large ion lithophile elements. This extensive database supports a model in which these ophiolites are derived from a single obducted nappe. This model is supported by the metamorphic pressure–temperature–time paths of the sole lithologies under the outcrops of the suture zone ophiolites. Palaeontological dating of sediment deposits directly under or sealing the obduction contact also support this model by temporally linking the emplacement of distant ophiolite outcrops. General emplacement during early Late Cretaceous time has been determined. A south-dipping subduction under the SAB shortly predating obduction has recently been proposed from the metamorphic and magmatic evolution preserved in the SAB crystalline basement, founding a model featuring opposite-direction subduction from at least late Middle Jurassic to Early Cretaceous times. The emplacement of alkaline pillow basalts directly on the oceanic crust is dated as Early to mid-Cretaceous. These dates argue the existence of abnormal mantle heat flows which may be responsible for a decrease in the density of the 80 Ma-old oceanic lithosphere prior to its obduction onto the SAB–TAP. We present a detailed review of recent data to further constrain the structural and geodynamic evolution of this sector and to define the tectonic set-up just prior to the obduction event.

Published
2017
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13. Spacecraft outgassing, a largely underestimated phenomenon

Author

Hassig, M., primary, Altwegg, K., additional, Balsiger, H., additional, Calmonte, U., additional, Jackel, A., additional, Schlappi, B., additional, Semon, T., additional, Wurz, P., additional, Berthelier, J. J., additional, De Keyser, J., additional, Fiethe, B., additional, Fuselier, S. A., additional, Mall, U., additional, Reme, H., additional, and Rubin, M., additional

Published
2011
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23. Epidemiological investigations of abortions due to Neospora caninumon Swiss dairy farms

Author

Hassig, M. and Gottstein, B.

Abstract

Abortions apparently due to Neospora caninumin two Swiss dairy herds were investigated by means of a PCR and ELISA, and other potential causes were eliminated. In addition, a case‐control study of 24 case herds and 24 control herds indicated that N caninum‐associated abortions were more likely to occur in herds with antibodies to Coxiella bumetii(with an odds ratio [OR] of 3.38 with a 95 per cent confidence interval [cl] of 1.82 to 6.22), whereas the likelihood was less in herds with antibodies to Leptospiraspecies (OR 0.34, 95 per cent ci 0.13 to 0.75), or in herds with antibodies to bovine viral diarrhoea (BvD) virus (OR 0.75, 95 per cent ci 0.56 to 1.00), or Chiamydia psittaci(OR 0.18,95 per cent ci 0.09 to 0.35), or in herds in which BVD virus had been isolated from an aborted fetus (OR 0.11, 95 per cent ci 0.02 to 0.58).

Published
2002
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25. Development and application of new condition assessment methods for power transformers

Author

Aschwanden, T., Hassig, M., Fuhr, J., Lorin, P., Der Houhanessian, V., Zaengl, W., Schenk, A., Zweiacker, P., and Piras, A.

Subjects
polarisation currents, adaptive threshold, depolarisation currents, transfer function measurement, partial discharge measurement, online monitoring, power transformer insulation, partial discharge detection, offline diagnosis, power transformers, monitoring, insulation testing, ageing, model-based software approach, transfer functions, faulty conditions definition, power transformer testing, condition assessment methods
Abstract

Recent advances in the application of nontraditional methods and procedures for offline diagnosis and online monitoring of new and service-aged power transformers are discussed. Advanced offline methods are based on the main operational stresses (electrical, mechanical, thermal) and on typical failure modes: measurement of polarisation and depolarisation currents, electrical detection of partial discharges and measurement of the transfer function. A pilot installation of an online monitoring system on a strategically important transformer is described. The measured data of the built-in sensors (e.g. load, temperatures, gas and moisture in oil, overvoltages) are analyzed using a model-based software approach with an adaptive threshold to define faulty conditions

26. Lack of correlation between serum titres of interferon alpha, beta, natural killer cell activity and clinical susceptibility in mice infected with two isolates of lymphocytic choriomeningitis virus

Author

Leist, T. P., Aguet, M., Hassig, M., Pevear, D. C., Pfau, C. J., and Zinkernagel, R. M.

Abstract

Intracerebral infection of adult immunocompetent mice with most strains of lymphocytic choriomeningitis virus (LCMV) caused a systemic infection and led to severe meningoencephalitis and death due to the induced T cell immune response. The susceptibility of congenic mice to the two plaque variants Docile and Aggressive of LCMV strain UBC was shown to be mouse strain-dependent. To investigate the possible correlation between acid-stable interferon (IFN) and natural killer (NK) cell responses and the susceptibility to the two UBC LCMV substrains, serum titres of acid-stable antiviral activity, presumably IFN-alpha, beta and NK cell activities were determined in various mouse strains at different times after intracerebral infection. The two viral isolates induced comparable IFN-alpha, beta serum titres and caused similar NK activities in the same mouse strain. Between different mouse strains, marked differences in the kinetics and amount of IFN production were observed, yet there was no correlation with the susceptibility to the two UBC LCMV substrains. Additionally, there was no correlation between the magnitude of the IFN-alpha, beta serum titres and the NK activities induced in the spleen by the viral inocula. Overall, the findings suggest that levels of circulating IFN-alpha, beta are only of minor importance for the development of LCM disease.

27. Ion composition at comet 67P near perihelion: Rosetta observations and model-based interpretation

Author

Odelstad, E., Rubin, Martin, Bieler, André, Tzou, Chia-Yu, Gasc, Sébastien, Vigren, E., Biver, N., Altwegg, Kathrin, Calmonte, Ursina Maria, Fougere, N., Hansen, K. C., Fiethe, B., Fuselier, S. A., Hassig, M., Berthelier, J.-J., De Keyser, J., Gombosi, T. I., Balsiger, Hans, Galand, M., Heritier, K. L., Vuitton, V., Eriksson, A. I., Kopp, Ernest, Combi, M. R., and Beth, A.

Subjects
13. Climate action, 530 Physics, 520 Astronomy, 620 Engineering
Abstract

We present the ion composition in the coma of comet 67P with newly detected ion species over the 28–37 u mass range, probed by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Double Focusing Mass Spectrometer (DFMS). In summer 2015, the nucleus reached its highest outgassing rate and ion-neutral reactions started to take place at low cometocentric distances. Minor neutrals can efficiently capture protons from the ion population, making the protonated version of these neutrals a major ion species. So far, only NH+₄ has been reported at comet 67P. However, there are additional neutral species with proton affinities higher than that of water (besides NH₃) that have been detected in the coma of comet 67P: CH₃OH, HCN, H₂CO and H₂S. Their protonated versions have all been detected. Statistics showing the number of detections with respect to the number of scans are presented. The effect of the negative spacecraft potential probed by the Rosetta Plasma Consortium/LAngmuir Probe on ion detection is assessed. An ionospheric model has been developed to assess the different ion density profiles and compare them to the ROSINA/DFMS measurements. It is also used to interpret the ROSINA/DFMS observations when different ion species have similar masses, and their respective densities are not high enough to disentangle them using the ROSINA/DFMS high-resolution mode. The different ion species that have been reported in the coma of 67P are summarized and compared with the ions detected at comet 1P/Halley during the Giotto mission.

33. Angle between the patellar ligament and tibial plateau in dogs with partial rupture of the cranial cruciate ligament.

Author

Schwandt CS, Bohorquez-Vanelli A, Tepic S, Hassig M, Dennler R, Vezzoni A, and Montavon PM

Subjects
Animals, Biomechanical Phenomena, Dogs injuries, Dogs physiology, Patellar Ligament physiology, Radiography, Stifle injuries, Stifle physiology, Tibia physiology, Anterior Cruciate Ligament Injuries, Dogs anatomy & histology, Patellar Ligament anatomy & histology, Range of Motion, Articular physiology, Stifle diagnostic imaging, Tibia anatomy & histology
Abstract

Objective: To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) in stifle joints of dogs with partial rupture of the cranial cruciate ligament (CrCL) for comparison with data obtained for stifle joints in dogs with intact CrCLs., Sample Population: 60 stifle joints of 54 dogs with surgically confirmed partial CrCL rupture., Procedures: Mediolateral radiographic views of the stifle joints were obtained, and the angles between the patellar ligament and the conventionally defined tibial plateau (angle gamma) and between the patellar ligament and the common tangent to the TFCP (angle alpha) were measured at incidental stifle joint flexion (angle beta) by 2 independent observers. Data underwent linear regression analysis and were compared with findings in joints of dogs without degenerative joint disease., Results: In stifle joints of dogs with a partial rupture of the CrCL, angles gamma and alpha were 5 degrees and 2 degrees larger than each corresponding angle in healthy canine joints. At 100 degrees of flexion, the patellar ligament was perpendicular to the conventionally defined tibial plateau. At 110 degrees of flexion, the patellar ligament was perpendicular to the common tangent at the TFCP., Conclusions and Clinical Relevance: In dogs, stifle joints with partially ruptured CrCLs have marginally larger angles between the patellar ligament and the tibial plateau, compared with joints with intact CrCLs; at equivalent angles of flexion, comparatively greater shear force affects the CrCLs in stifle joints with partial CrCL ruptures.

Published
2006
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34. Inclination of the patellar ligament in relation to flexion angle in stifle joints of dogs without degenerative joint disease.

Author

Dennler R, Kipfer NM, Tepic S, Hassig M, and Montavon PM

Subjects
Animals, Biomechanical Phenomena, Cadaver, Dogs physiology, Patellar Ligament physiology, Stifle physiology, Dogs anatomy & histology, Patellar Ligament anatomy & histology, Range of Motion, Articular physiology, Stifle anatomy & histology
Abstract

Objective: To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) throughout the full range of motion of the stifle joint in dogs and determine the flexion angles at which the patellar ligament is perpendicular to the tibial plateau or to the common tangent., Sample Population: 16 hind limbs from cadavers of 9 adult dogs without radiographically detectable degenerative joint disease., Procedures: Mediolateral radiographic views of the stifle joints from full extension through full flexion were obtained (10 degrees increments). Angles between the tibial and femoral long axes (beta), between the patellar ligament and the tibial plateau gamma), and between the patellar ligament and the common tangent at TFCP (alpha) were measured. Data were analyzed via simple linear regression., Results: In canine stifle joints, angles gamma and alpha decreased linearly with increasing flexion (angle beta). The patellar ligament was perpendicular to the tibial plateau and perpendicular to the common tangent at the TFCP at 90 degrees and 110 degrees of flexion, respectively., Conclusions and Clinical Relevance: By use of the conventionally defined tibial plateau, data suggest that at approximately 90 degrees of flexion in stifle joints of dogs, shear force in the sagittal plane exerted on the proximal portion of the tibia shifts the loading from the cranial to the caudal cruciate ligament. Analyses involving the common tangent at the TFCP (a more anatomically representative reference point) identified this crossover point at approximately 110 degrees of joint flexion.

Published
2006
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35. Studies on the supply of immunoglobulin G to newborn camel calves (Camelus dromedarius).

Author

Kamber R, Farah Z, Rusch P, and Hassig M

Subjects
Animal Husbandry, Animals, Animals, Newborn blood, Camelus blood, Immunoglobulin G blood, Reference Values, Time Factors, Animals, Newborn immunology, Camelus immunology, Colostrum immunology, Immunity, Maternally-Acquired, Immunoglobulin G analysis
Abstract

A major problem in camel productivity is the high mortality rate of camel calves in the first 3 months. The causes for mortality are mainly poor management practice and infectious diseases. The purpose of this research, carried out on a ranch in Kenya, was to determine the immunoglobulin G (IgG) concentration in camel colostrum as well as the extent of the calves' passive immunization by maternal antibodies. IgG concentration in colostrum and in the serum of the calf were measured during the first 3 d of life. Evaluation was carried out by comparing the respective values with those for horses and cattle. The average IgG concentration in the camel colostrum was higher than that found in literature for horses and cattle. IgG concentration in the serum of the camel calves reached its maximum 24 h after birth. In 39% of the examined calves, this maximum concentration was below 4 g/l, which is considered to be the critical value in horses and cattle. 61% of the calves achieved an IgG concentration of over 4 g/l. Since there is no correlation between IgG level in colostrum and early mortality, the results indicate that low colostrum intake during the first 24 h of life and not low IgG concentration in colostrum is presumably one of the main causes of early calf mortality. Therefore, it was recommended that the care of the newborn calves by herdsmen should be improved.

Published
2001
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