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178 results on '"Ostertag, R."'

2. Beta decay of molecular tritium

Author

Lin, Y. -T., Burritt, T. H., Claessens, C., Holman, G., Kallander, M., Machado, E., Minter, L. I., Ostertag, R., Parno, D. S., Pedersen, J., Peterson, D. A., Robertson, R. G. H., Smith, E. B., Van Wechel, T. D., and Hernández, A. P. Vizcaya

Subjects
Nuclear Experiment
Abstract

The beta decay of tritium in the form of molecular TT is the basis of sensitive experiments to measure neutrino mass. The final-state electronic, vibrational, and rotational excitations modify the beta spectrum significantly, and are obtained from theory. We report measurements of the branching ratios to specific ionization states for the isotopolog HT. Two earlier, concordant measurements gave branching ratios of HT to the bound HHe$^+$ ion of 89.5% and 93.2%, in sharp disagreement with the theoretical prediction of 55-57%, raising concerns about the theory's reliability in neutrino mass experiments. Our result, 56.5(6)%, is compatible with the theoretical expectation and disagrees strongly with the previous measurements., Comment: 6 pages, 4 figures (Updated with minor typographical fixes)

Published
2020
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3. Strong floristic distinctiveness across Neotropical successional forests

Author

Jakovac, C.C., Meave, J.A., Bongers, F., Letcher, S.G., Dupuy, J.M., Piotto, D., Rozendaal, D.M.A., Peña-Claros, M., Craven, D., Santos, B.A., Siminski, A., Fantini, A.C., Hernández-Jaramillo, A., Idárraga, A., Junqueira, A.B., Zambrano, A.M.A., De Jong, B.H.J., Pinho, B.X., Finegan, B., Castellano-Castro, C., Zambiazi, D.C., Dent, D.H., García, D.H., Kennard, D., Delgado, D., Broadbent, E.N., Ortiz-Malavassi, E., Pérez-García, E.A., Lebrija-Trejos, E., Berenguer, E., Marín-Spiotta, E., Alvarez-Davila, E., De Sá Sampaio, E.V., Melo, F., Elias, F., França, F., Oberleitner, F., Mora, F., Williamson, G.B., Dalla Colletta, G., Cabral, G.A.L., Derroire, G., Fernandes, G.W., Van Der Wal, H., Teixeira, H.M., Vester, H.F.M., García, H., Vieira, I.C.G., Jiménez-Montoya, J., De Almeida-Cortez, J.S., Hall, J.S., Chave, J., Zimmerman, J.K., Nieto, J.E., Ferreira, J., Rodríguez-Velázquez, J., Ruíz, J., Barlow, J., Aguilar-Cano, J., Hernández-Stefanoni, J.L., Engel, J., Becknell, J.M., Zanini, K., Lohbeck, M., Tabarelli, M., Romero-Romero, M.A., Uriarte, M., Veloso, M.D.M., Espírito-Santo, M.M., Van Der Sande, M.T., Van Breugel, M., Martínez-Ramos, M., Schwartz, N.B., Norden, N., Pérez-Cárdenas, N., González-Valdivia, N., Petronelli, P., Balvanera, P., Massoca, P., Brancalion, P.H.S., Villa, P.M., Hietz, P., Ostertag, R., López-Camacho, R., César, R.G., Mesquita, R., Chazdon, R.L., Muñoz, R., DeWalt, S.J., Müller, S.C., Durán, S.M., Martins, S.V., Ochoa-Gaona, S., Rodríguez-Buritica, S., Aide, T.M., Bentos, T.V., Moreno, V.D.S., Granda, V., Thomas, W., Silver, W.L., Nunes, Y.R.F., Poorter, L., Jakovac, C.C., Meave, J.A., Bongers, F., Letcher, S.G., Dupuy, J.M., Piotto, D., Rozendaal, D.M.A., Peña-Claros, M., Craven, D., Santos, B.A., Siminski, A., Fantini, A.C., Hernández-Jaramillo, A., Idárraga, A., Junqueira, A.B., Zambrano, A.M.A., De Jong, B.H.J., Pinho, B.X., Finegan, B., Castellano-Castro, C., Zambiazi, D.C., Dent, D.H., García, D.H., Kennard, D., Delgado, D., Broadbent, E.N., Ortiz-Malavassi, E., Pérez-García, E.A., Lebrija-Trejos, E., Berenguer, E., Marín-Spiotta, E., Alvarez-Davila, E., De Sá Sampaio, E.V., Melo, F., Elias, F., França, F., Oberleitner, F., Mora, F., Williamson, G.B., Dalla Colletta, G., Cabral, G.A.L., Derroire, G., Fernandes, G.W., Van Der Wal, H., Teixeira, H.M., Vester, H.F.M., García, H., Vieira, I.C.G., Jiménez-Montoya, J., De Almeida-Cortez, J.S., Hall, J.S., Chave, J., Zimmerman, J.K., Nieto, J.E., Ferreira, J., Rodríguez-Velázquez, J., Ruíz, J., Barlow, J., Aguilar-Cano, J., Hernández-Stefanoni, J.L., Engel, J., Becknell, J.M., Zanini, K., Lohbeck, M., Tabarelli, M., Romero-Romero, M.A., Uriarte, M., Veloso, M.D.M., Espírito-Santo, M.M., Van Der Sande, M.T., Van Breugel, M., Martínez-Ramos, M., Schwartz, N.B., Norden, N., Pérez-Cárdenas, N., González-Valdivia, N., Petronelli, P., Balvanera, P., Massoca, P., Brancalion, P.H.S., Villa, P.M., Hietz, P., Ostertag, R., López-Camacho, R., César, R.G., Mesquita, R., Chazdon, R.L., Muñoz, R., DeWalt, S.J., Müller, S.C., Durán, S.M., Martins, S.V., Ochoa-Gaona, S., Rodríguez-Buritica, S., Aide, T.M., Bentos, T.V., Moreno, V.D.S., Granda, V., Thomas, W., Silver, W.L., Nunes, Y.R.F., and Poorter, L.

Abstract

Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained.

Published
2022

4. Strong floristic distinctiveness across Neotropical successional forests

Author

Environmental Sciences, Jakovac, C.C., Meave, J.A., Bongers, F., Letcher, S.G., Dupuy, J.M., Piotto, D., Rozendaal, D.M.A., Peña-Claros, M., Craven, D., Santos, B.A., Siminski, A., Fantini, A.C., Rodrigues, A.C., Hernández-Jaramillo, A., Idárraga, A., Junqueira, A.B., Zambrano, A.M.A., De Jong, B.H.J., Pinho, B.X., Finegan, B., Castellano-Castro, C., Zambiazi, D.C., Dent, D.H., García, D.H., Kennard, D., Delgado, D., Broadbent, E.N., Ortiz-Malavassi, E., Pérez-García, E.A., Lebrija-Trejos, E., Berenguer, E., Marín-Spiotta, E., Alvarez-Davila, E., De Sá Sampaio, E.V., Melo, F., Elias, F., França, F., Oberleitner, F., Mora, F., Williamson, G.B., Dalla Colletta, G., Cabral, G.A.L., Derroire, G., Fernandes, G.W., Van Der Wal, H., Teixeira, H.M., Vester, H.F.M., García, H., Vieira, I.C.G., Jiménez-Montoya, J., De Almeida-Cortez, J.S., Hall, J.S., Chave, J., Zimmerman, J.K., Nieto, J.E., Ferreira, J., Rodríguez-Velázquez, J., Ruíz, J., Barlow, J., Aguilar-Cano, J., Hernández-Stefanoni, J.L., Engel, J., Becknell, J.M., Zanini, K., Lohbeck, M., Tabarelli, M., Romero-Romero, M.A., Uriarte, M., Veloso, M.D.M., Espírito-Santo, M.M., Van Der Sande, M.T., Van Breugel, M., Martínez-Ramos, M., Schwartz, N.B., Norden, N., Pérez-Cárdenas, N., González-Valdivia, N., Petronelli, P., Balvanera, P., Massoca, P., Brancalion, P.H.S., Villa, P.M., Hietz, P., Ostertag, R., López-Camacho, R., César, R.G., Mesquita, R., Chazdon, R.L., Muñoz, R., DeWalt, S.J., Müller, S.C., Durán, S.M., Martins, S.V., Ochoa-Gaona, S., Rodríguez-Buritica, S., Aide, T.M., Bentos, T.V., Moreno, V.D.S., Granda, V., Thomas, W., Silver, W.L., Nunes, Y.R.F., Poorter, L., Environmental Sciences, Jakovac, C.C., Meave, J.A., Bongers, F., Letcher, S.G., Dupuy, J.M., Piotto, D., Rozendaal, D.M.A., Peña-Claros, M., Craven, D., Santos, B.A., Siminski, A., Fantini, A.C., Rodrigues, A.C., Hernández-Jaramillo, A., Idárraga, A., Junqueira, A.B., Zambrano, A.M.A., De Jong, B.H.J., Pinho, B.X., Finegan, B., Castellano-Castro, C., Zambiazi, D.C., Dent, D.H., García, D.H., Kennard, D., Delgado, D., Broadbent, E.N., Ortiz-Malavassi, E., Pérez-García, E.A., Lebrija-Trejos, E., Berenguer, E., Marín-Spiotta, E., Alvarez-Davila, E., De Sá Sampaio, E.V., Melo, F., Elias, F., França, F., Oberleitner, F., Mora, F., Williamson, G.B., Dalla Colletta, G., Cabral, G.A.L., Derroire, G., Fernandes, G.W., Van Der Wal, H., Teixeira, H.M., Vester, H.F.M., García, H., Vieira, I.C.G., Jiménez-Montoya, J., De Almeida-Cortez, J.S., Hall, J.S., Chave, J., Zimmerman, J.K., Nieto, J.E., Ferreira, J., Rodríguez-Velázquez, J., Ruíz, J., Barlow, J., Aguilar-Cano, J., Hernández-Stefanoni, J.L., Engel, J., Becknell, J.M., Zanini, K., Lohbeck, M., Tabarelli, M., Romero-Romero, M.A., Uriarte, M., Veloso, M.D.M., Espírito-Santo, M.M., Van Der Sande, M.T., Van Breugel, M., Martínez-Ramos, M., Schwartz, N.B., Norden, N., Pérez-Cárdenas, N., González-Valdivia, N., Petronelli, P., Balvanera, P., Massoca, P., Brancalion, P.H.S., Villa, P.M., Hietz, P., Ostertag, R., López-Camacho, R., César, R.G., Mesquita, R., Chazdon, R.L., Muñoz, R., DeWalt, S.J., Müller, S.C., Durán, S.M., Martins, S.V., Ochoa-Gaona, S., Rodríguez-Buritica, S., Aide, T.M., Bentos, T.V., Moreno, V.D.S., Granda, V., Thomas, W., Silver, W.L., Nunes, Y.R.F., and Poorter, L.

Published
2022

6. Influences of N-fixing and non-N-fixing vegetation and invasive fish on water chemistry of Hawaiian anchialine ponds

Author

Dudley, B.D., MacKenzie, R.A., Sakihara, T.S., Dulaiova, H., Waters, C.A., Hughes, R.F., and Ostertag, R.

Subjects
Coastal ecosystems -- Analysis, Water chemistry -- Analysis, Fish ponds -- Research, Earth sciences, Science and technology
Abstract

Abstract: In coastal waters, it remains unclear how terrestrial invasive species might alter nutrient availability and thus affect bottom-up control of primary production. Anchialine ponds are tidal- and groundwater-fed coastal [...]

Published
2014
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7. Hawai'i forest review: Synthesizing the ecology, evolution, and conservation of a model system

Author

Barton, K.E., Westerband, A., Ostertag, R., Stacy, E., Winter, K., Drake, D.R., Fortini, L.B., Litton, C.M., Cordell, S., Krushelnycky, P., Kawelo, K., Feliciano, K., Bennett, G., Knight, Tiffany, Barton, K.E., Westerband, A., Ostertag, R., Stacy, E., Winter, K., Drake, D.R., Fortini, L.B., Litton, C.M., Cordell, S., Krushelnycky, P., Kawelo, K., Feliciano, K., Bennett, G., and Knight, Tiffany

Abstract

As the most remote archipelago in the world, the Hawaiian Islands are home to a highly endemic and disharmonic biota that has fascinated biologists for centuries. Forests are the dominant terrestrial biome in Hawai‘i, spanning complex, heterogeneous climates across substrates that vary tremendously in age, soil structure, and nutrient availability. Species richness is low in Hawaiian forests compared to other tropical forests, as a consequence of dispersal limitation from continents and adaptive radiations in only some lineages, and forests are dominated by the widespread Metrosideros species complex. Low species richness provides a relatively tractable model system for studies of community assembly, local adaptation, and species interactions. Moreover, Hawaiian forests provide insights into predicted patterns of evolution on islands, revealing that while some evidence supports “island syndromes,” there are exceptions to them all. For example, Hawaiian plants are not as a whole less defended against herbivores, less dispersible, more conservative in resource use, or more slow-growing than their continental relatives. Clearly, more work is needed to understand the drivers, sources, and constraints on phenotypic variation among Hawaiian species, including both widespread and rare species, and to understand the role of this variation for ecological and evolutionary processes, which will further contribute to conservation of this unique biota. Today, Hawaiian forests are among the most threatened globally. Resource management failures – the proliferation of non-native species in particular – have led to devastating declines in native taxa and resulted in dominance by novel species assemblages. Conservation and restoration of Hawaiian forests now rely on managing threats including climate change, ongoing species introductions, novel pathogens, lost mutualists, and altered ecosystem dynamics through the use of diverse tools and strategies grounded in basic ecological, evo

Published
2021

11. Hydrological effects of tree invasion on a dry coastal Hawaiian ecosystem

Author

Dudley, B.D., primary, Hughes, R.F., additional, Asner, G.P., additional, Baldwin, J.A., additional, Miyazawa, Y., additional, Dulai, H., additional, Waters, C., additional, Bishop, J., additional, Vaughn, N.R., additional, Yeh, J., additional, Kettwich, S., additional, MacKenzie, R.A., additional, Ostertag, R., additional, and Giambelluca, T., additional

Published
2020
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13. Global effects of non-native tree species on multiple ecosystem services

Author

Castro-Diez, P, Vaz, AS, Silva, JS, van Loo, M, Alonso, A, Aponte, C, Bayon, A, Bellingham, PJ, Chiuffo, MC, DiManno, N, Julian, K, Kandert, S, La Porta, N, Marchante, H, Maule, HG, Mayfield, MM, Metcalfe, D, Monteverdi, MC, Nunez, MA, Ostertag, R, Parker, IM, Peltzer, DA, Potgieter, LJ, Raymundo, M, Rayome, D, Reisman-Berman, O, Richardson, DM, Roos, RE, Saldana, A, Shackleton, RT, Torres, A, Trudgen, M, Urban, J, Vicente, JR, Vila, M, Ylioja, T, Zenni, RD, Godoy, O, Castro-Diez, P, Vaz, AS, Silva, JS, van Loo, M, Alonso, A, Aponte, C, Bayon, A, Bellingham, PJ, Chiuffo, MC, DiManno, N, Julian, K, Kandert, S, La Porta, N, Marchante, H, Maule, HG, Mayfield, MM, Metcalfe, D, Monteverdi, MC, Nunez, MA, Ostertag, R, Parker, IM, Peltzer, DA, Potgieter, LJ, Raymundo, M, Rayome, D, Reisman-Berman, O, Richardson, DM, Roos, RE, Saldana, A, Shackleton, RT, Torres, A, Trudgen, M, Urban, J, Vicente, JR, Vila, M, Ylioja, T, Zenni, RD, and Godoy, O

Abstract

Non-native tree (NNT) species have been transported worldwide to create or enhance services that are fundamental for human well-being, such as timber provision, erosion control or ornamental value; yet NNTs can also produce undesired effects, such as fire proneness or pollen allergenicity. Despite the variety of effects that NNTs have on multiple ecosystem services, a global quantitative assessment of their costs and benefits is still lacking. Such information is critical for decision-making, management and sustainable exploitation of NNTs. We present here a global assessment of NNT effects on the three main categories of ecosystem services, including regulating (RES), provisioning (PES) and cultural services (CES), and on an ecosystem disservice (EDS), i.e. pollen allergenicity. By searching the scientific literature, country forestry reports, and social media, we compiled a global data set of 1683 case studies from over 125 NNT species, covering 44 countries, all continents but Antarctica, and seven biomes. Using different meta-analysis techniques, we found that, while NNTs increase most RES (e.g. climate regulation, soil erosion control, fertility and formation), they decrease PES (e.g. NNTs contribute less than native trees to global timber provision). Also, they have different effects on CES (e.g. increase aesthetic values but decrease scientific interest), and no effect on the EDS considered. NNT effects on each ecosystem (dis)service showed a strong context dependency, varying across NNT types, biomes and socio-economic conditions. For instance, some RES are increased more by NNTs able to fix atmospheric nitrogen, and when the ecosystem is located in low-latitude biomes; some CES are increased more by NNTs in less-wealthy countries or in countries with higher gross domestic products. The effects of NNTs on several ecosystem (dis)services exhibited some synergies (e.g. among soil fertility, soil formation and climate regulation or between aesthetic values and

Published
2019

14. Global effects of non-native tree species on multiple ecosystem services

Author

Castro-Díez, Pilar, Vaz, A.S., Silva, J.S., van Loo, M., Alonso, Álvaro, Aponte, Cristina, Bayón, Á., Bellingham, Peter J., Chiuffo, M.C., DiManno, N., Julian, K., Kandert, S., Porta, N.L., Marchante, H., Maule, H.G., Mayfield, Margaret M., Metcalfe, D., Monteverdi, M.C., Núñez, M.A., Ostertag, R., Parker, I.M., Peltzer, D.A., Potgieter, L.J., Raymundo, M., Rayome, D., Reisman-Berman, O., Richardson, D.M., Roos, R.E., Saldaña, A., Shackleton, R.T., Torres, A., Trudgen, M., Urban, J., Vicente, J.R., Vilà, Montserrat, Ylioja, T., Zenni, R.D., Godoy, Óscar, Castro-Díez, Pilar, Vaz, A.S., Silva, J.S., van Loo, M., Alonso, Álvaro, Aponte, Cristina, Bayón, Á., Bellingham, Peter J., Chiuffo, M.C., DiManno, N., Julian, K., Kandert, S., Porta, N.L., Marchante, H., Maule, H.G., Mayfield, Margaret M., Metcalfe, D., Monteverdi, M.C., Núñez, M.A., Ostertag, R., Parker, I.M., Peltzer, D.A., Potgieter, L.J., Raymundo, M., Rayome, D., Reisman-Berman, O., Richardson, D.M., Roos, R.E., Saldaña, A., Shackleton, R.T., Torres, A., Trudgen, M., Urban, J., Vicente, J.R., Vilà, Montserrat, Ylioja, T., Zenni, R.D., and Godoy, Óscar

Abstract

Non-native tree (NNT) species have been transported worldwide to create or enhance services that are fundamental for human well-being, such as timber provision, erosion control or ornamental value; yet NNTs can also produce undesired effects, such as fire proneness or pollen allergenicity. Despite the variety of effects that NNTs have on multiple ecosystem services, a global quantitative assessment of their costs and benefits is still lacking. Such information is critical for decision-making, management and sustainable exploitation of NNTs. We present here a global assessment of NNT effects on the three main categories of ecosystem services, including regulating (RES), provisioning (PES) and cultural services (CES), and on an ecosystem disservice (EDS), i.e. pollen allergenicity. By searching the scientific literature, country forestry reports, and social media, we compiled a global data set of 1683 case studies from over 125 NNT species, covering 44 countries, all continents but Antarctica, and seven biomes. Using different meta-analysis techniques, we found that, while NNTs increase most RES (e.g. climate regulation, soil erosion control, fertility and formation), they decrease PES (e.g. NNTs contribute less than native trees to global timber provision). Also, they have different effects on CES (e.g. increase aesthetic values but decrease scientific interest), and no effect on the EDS considered. NNT effects on each ecosystem (dis)service showed a strong context dependency, varying across NNT types, biomes and socio-economic conditions. For instance, some RES are increased more by NNTs able to fix atmospheric nitrogen, and when the ecosystem is located in low-latitude biomes; some CES are increased more by NNTs in less-wealthy countries or in countries with higher gross domestic products. The effects of NNTs on several ecosystem (dis)services exhibited some synergies (e.g. among soil fertility, soil formation and climate regulation or between aesthetic values and

Published
2019

15. Sachverzeichnis

Author

Lubarsch, O., von Ostertag, R., Frei, W., Lubarsch, O., editor, von Ostertag, R., editor, and Frei, W., editor

Published
1931
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16. Namenverzeichnis

Author

Lubarsch, O., von Ostertag, R., Frei, W., Lubarsch, O., editor, von Ostertag, R., editor, and Frei, W., editor

Published
1931
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17. OpenNahele: the open Hawaiian forest plot database

Author

Craven, Dylan, Knight, Tiffany, Barton, K.E., Bialic-Murphy, L., Cordell, S., Giardina, C.P., Gillespie, T.W., Ostertag, R., Sack, L., Chase, J.M., Craven, Dylan, Knight, Tiffany, Barton, K.E., Bialic-Murphy, L., Cordell, S., Giardina, C.P., Gillespie, T.W., Ostertag, R., Sack, L., and Chase, J.M.

Abstract

Background This data paper provides a description of OpenNahele, the open Hawaiian forest plot database. OpenNahele includes 530 forest plots across the Hawaiian archipelago containing 43,590 individuals of 185 native and alien tree, shrub and tree fern species across six islands. We include estimates of maximum plant size (D950.1 and Dmax3) for 58 woody plant species, a key functional trait associated with dispersal distance and competition for light. OpenNahele can serve as a platform to test key ecological, evolutionary and conservation questions in a hotspot archipelago. New information OpenNahele is the first database that compiles data from a large number of forest plots across the Hawaiian archipelago to allow broad and high resolution studies of biodiversity patterns.

Published
2018

22. Datenschutzkonforme Zusammenführung und Abfrage von Biomaterialverwaltungsdaten mit medizinischen Daten für eine klinische Forschergruppe

Author

Ostertag, R, Sax, U, and Helbing, K

Subjects
i2b2, Datenzusammenführung, ddc: 610, Biobanken, Biomaterialverwaltungsdaten, 610 Medical sciences, Medicine
Abstract

Einleitung: Die Verfügbarkeit von biologischen und dazugehörigen klinischen Daten wird zunehmend wichtiger, insbesondere für die translationale Forschung [ref:1]. Zahlreiche Forschungsprojekte verfolgen ihre Ziele mit Hilfe von Biomaterialbanken und den entsprechenden Phänotypdaten[for full text, please go to the a.m. URL], Mainz//2011; 56. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 6. Jahrestagung der Deutschen Gesellschaft für Epidemiologie (DGEpi)

Published
2011
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25. Shock metamorphism and petrography of the Shergotty achondrite

Author

Stoeffler, D, Ostertag, R, Jammes, C, Pfannschmidt, G, and Sen Gupta, P. R

Subjects
Lunar And Planetary Exploration
Abstract

The shock history of the Shergotty meteorite has been evaluated by analyzing the observable shock effects. In addition, the results of petrographic and mineralogical analyses of new Shergotty subsamples are presented. The overall modal composition of these subsamples is similar to that of the other Shergotty samples, except for the rather high whitlockite content. The shock effects observed in the mineral constituents include mosaicism, deformation bands, planar fractures, and mechanical twin lamellae in clinopyroxene; isotropization of plagioclase with very rare remnants of birefringence; and planar deformation structures, mosaicism, and strongly reduced birefringence in quartz. Other shock effects include mechanical twinning of ilmenite, and localized in situ melting of neighboring minerals at the contact of low and high density phases. The observed shock effects could be explained by a single shock event.

Published
1986
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26. Bunte Breccia of the Ries - Continuous deposits of large impact craters

Author

Horz, F, Ostertag, R, and Rainey, D. A

Subjects
Lunar And Planetary Exploration
Abstract

The 26-km-diameter Ries impact crater in south Germany and the mechanism of ejection and emplacement associated with its formation about 15 Myr ago are discussed in detail, and the implications of the findings for models of crater formation on earth, moon, and planets are considered. Field observations and laboratory tests on 560-m core materials from nine locations are reported. The continuous deposits (Bunte Breccia) are found to be a chaotic mixture resulting from deposition at ambient temperatures in a highly turbulent environment, probably in the ballistic scenario proposed by Oberbeck et al. (1975), with an emplacement time of only about 5 min. Further impact parameters are estimated using the 'Z model' of Maxwell (1977): initial radius = 6.5 km, excavation depth = 1650 m, excavation volume = 136 cu km, and transient cavity volume = 230 cu km. The interpretation of lunar and planetary remote-sensing and in situ evidence from impact craters is reviewed in the light of the Ries findings. Numerous photographs, maps, diagrams, and tables illustrate the investigation.

Published
1983

27. Distribution and provenance of lunar highland rock types at North Ray Crater, Apollo 16

Author

Stoeffler, D, Ostertag, R, Borchardt, R, Malley, J, Rehfeldt, A, and Reimold, W. U

Subjects
Lunar And Planetary Exploration
Abstract

In connection with its selenographic setting in the central lunar highlands, the Apollo 16 landing site in the Descartes area is highly important as a prime sampling area for rocks which formed as part of the primordial crust and as a key location for the analysis of the deformation and transport of crustal material by impact processes. The present investigation is concerned with the North Ray crater, which is located on the N-S running boundary between the smooth Cayley plains to the west and the Descartes mountains to the east. Attention is given to aspects of selenography and location of samples, the ejecta distribution of post-Cayley impact craters, sample classification, the frequency distribution of rock types in the North Ray Crater ejecta, an interpretation of compositional and age data, a model of the target stratigraphy and excavation of North Ray Crater, and implications for the emplacement and provenance of North Ray target rocks.

Published
1982

32. Sitagliptin reduces plaque macrophage content and stabilises arteriosclerotic lesions in Apoe mice.

Author

Vittone, F., Liberman, A., Vasic, D., Ostertag, R., Esser, M., Walcher, D., Ludwig, A., Marx, N., and Burgmaier, M.

Abstract

Aims/hypothesis: Inhibitors of dipeptidyl peptidase-IV (DPP-IV), such as sitagliptin, increase glucagon-like peptide-1 (GLP-1) concentrations and are current treatment options for patients with type 2 diabetes mellitus. As patients with diabetes exhibit a high risk of developing severe atherosclerosis, we investigated the effect of sitagliptin on atherogenesis in Apoe mice. Methods: Apoe mice were fed a high-fat diet and treated with either sitagliptin or placebo for 12 weeks. Plaque size and plaque composition were analysed using Oil Red O staining and immunohistochemistry. Furthermore, in vitro experiments with the modified Boyden chamber and with gelatine zymography were performed to analyse the effects of GLP-1 on isolated human monocyte migration and metalloproteinase-9 (MMP-9) release. Results: Treatment of Apoe mice with sitagliptin significantly reduced plaque macrophage infiltration (the aortic root and aortic arch both showing a 67% decrease; p < 0.05) and plaque MMP-9 levels (aortic root showing a 69% and aortic arch a 58% reduction; both p < 0.01) compared with controls. Moreover, sitagliptin significantly increased plaque collagen content more than twofold (aortic root showing an increase of 58% and aortic arch an increase of 73%; both p < 0.05) compared with controls but did not change overall lesion size (8.1 ± 3.5% vs 5.1 ± 2.5% for sitagliptin vs controls; p = NS). In vitro, pretreatment of isolated human monocytes with GLP-1 significantly decreased cell migration induced by both monocyte chemotactic protein-1 and by the protein known as regulated on activation, normal T cell expressed and secreted (RANTES) in a concentration-dependent manner. Furthermore, GLP-1 significantly decreased MMP-9 release from isolated human monocyte-derived macrophages. Conclusions/interpretation: Sitagliptin reduces plaque inflammation and increases plaque stability, potentially by GLP-1-mediated inhibition of chemokine-induced monocyte migration and macrophage MMP-9 release. The effects observed may provide potential mechanisms for how DPP-IV inhibitors could modulate vascular disease in high-risk patients with type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

Published
2012
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41. Lunar meteorite Yamato-791197: Petrography, shock history and chemical composition

Author

Ostertag,R., Stoffler,D., Bischoff,A., Palme,H., Schultz,L., Spettel,B., Weber,H., Weckwerth,G., Wanke,H., and Institute fur Mineralogie/Institute fur Mineralogie/Institute fur Mineralogie/Max-Planck-Institut fur Chemie/Max-Planck-Institut fur Chemie/Max-Planck-Institut fur Chemie/Max-Planc-Institut fur Chemie/Max-Planck-Institut fur Chemie/Max-Planck-Institut fur Chemie

Abstract

Antarctic meteorite Yamato-791197 (Y-791197) is a polymict regolith breccia from the lunar highlands. It is composed of feldspathic lithic fragments, glasses and mineral fragments in a densely compacted, fine-grained, partly glassy matrix. Dominant lithologies are granulitic anorthosites, granulitic breccias, recrystallized fragmental breccias, microporphyritic and subophitic crystalline melt breccias, glass beads and irregularly shaped glassy particles. Some glasses are partly or totally devitrified. All mineral clasts are shocked, most plagioclase clasts are recrystallized. The shock effects in mineral and lithic clasts indicate pressures below 25GPa except for rare maskelynite and the shock-produced glassy particles. There is no indication that the meteorite as a whole has been shocked to more than 20GPa, consequently the shock pressures during the ejection event were less than 20GPa. Despite these low shock pressures, the breccia may have formed by shock-lithification caused by the ejection event. Chemical analyses of the bulk sample and of individual components indicate a source area free of KREEP, probably on the lunar farside. Differences in chemical composition (major and minor elements) may exist between the lunar frontside and the lunar farside. The content of Ga and Zn is remarkably high but heterogeneously distributed and may speak in favor of a moon-wide redistribution of volatile elements. The noble gas contents of Y-791197 are typical of lunar regolith and yield an exposure age of 450Ma. Y-791197 has a higher content in REE and noble gases and is more ferroan than lunar meteorite ALHA81005. Both differ compositionally from other lunar samples and despite their differences may be related to the same impact event.

Published
1986

42. Petrography, shock history, chemical composition and noble gas content of the lunar meteorites Yamato-82192 and -82193

Author

Bischoff,A., Palme,H., Weber,H.W., Stoffler,D., Braun,O., Spettel,B., Begemann,F., Wanke,H., Ostertag,R., and Institute fur Planetologie/Max-Planck-Institute fur Chemie/Max-Planck-Institute fur Chemie/Institute fur Planetologie/Max-Planck-Institute fur Chemie/Max-Planck-Institute fur Chemie/Max-Planck-Institute fur Chemie/Max-Planck-Institute fur Chemie/Institute fur Planetologie

Abstract

The Antarctic meteorites Yamato-82192 and -82193 are lunar polymict shock-lithified fragmental breccias with a minor regolith component. They are probably paired. The breccias are composed of a great variety of lithic and mineral fragments embedded in a fine-grained, densely compacted clastic matrix. Recrystallized feldspathic rocks and breccias, and granulitic lithologies are by far the dominant rock types. Crystalline impact melt breccias are common, however the amount of devitrified glasses is negligible. Glasses, common in ALHA81005,are missing in Y-82192 and -82193. Both samples contain some large basaltic clasts. All mineral and lithic clasts are shocked, and most plagioclases are recrystallized. We found no indication that the meteorite as a whole has been shocked to more than 20 GPa. These regolith breccias may have suffered peak shock pressures in the order of 10 GPa during the lithification event. The chemical composition of Y-82192 is very similar to that of the other lunar meteorites. Major differences are the low absolute abundances of REE and their flat chondrite normalized patterns. Other incompatible elements such as Hf and K also have comparatively low concentrations similar to the REE. The siderophile elements Ni, Co, Ir, and Au have similar abundances to other lunar highland samples. There appears to be a uniform signature of siderophile elements in the old lunar highlands away from the large basins of the front side of the Moon. The noble gas content of Y-82192 is entirely different from that of Y-791197 and ALHA81005. The light noble gasses He, Ne, and Ar are dominated by spallogenic and radiogenic components while the trapped gasses are similar to those in the Apollo 17 boulder and to those of "normal" meteorites. There is no indication that Y-82192 contains, or ever contained, any solar-wind implanted noble gases.

Published
1987

43. Shock metamorphism and petrography of the Shergotty achondrite

Author

Stöffler, D, Ostertag, R, Jammes, C, Pfannschmidt, G, Gupta, P.R.Sen, Simon, S.B, Papike, J.J, and Beauchamp, R.H

Abstract

The Shergotty subsamples 1 and 12 consist of augite and pigeonite (67.5%), maskelynite (24%), ilmenite and titanomagnetite (2%), pyrrhotite (0.4%), whitlockite (1.8%), apatite (0.1%), quartz (0.5%), baddeleyite (trace), fayalite (0.4%), mesostasis (3%), and shock-induced local, polymineralic melt products (0.6%). The overall modal composition is similar to other Shergotty samples except for the rather high whitlockite content. The shock effects observed in the mineral constituents include mosaicism, deformation bands, planar fractures, and mechanical twin lamellae in clinopyroxene; isotropization of plagioclase with very rare remnants of birefringence; planar deformation structures, mosaicism, and strongly reduced birefringence in quartz; mechanical twinning of ilmenite; localized in situmelting of neighbouring minerals at the contact of low and high density phases. Based on the refractive index of maskelynite (average: 1.5467 with average An-content of 49%) and the degree of isotropization of the plagioclase an equilibrium shock pressure of 29 ± 1 GPa is derived. The inferred post-shock temperature is 200 ± 20°C. No heating event could have exceeded 400°C (DUKE, 1968). Local stress and temperature concentrations reach 60–80 GPa and 1600–2000°C. The observed shock effects can be explained by a single shock event. A second, weaker shock event as found by others appears to be highly improbable. Equilibrium shock pressures and post-shock temperatures for the other known shergottites are 31 ±2 GPa and 220 ± 50°C(Zagami), 43 ± 2 GPa and 400–800°C (ALHA 77005). The pressure estimate for EETA 79001 by Lambert (1985) is confirmed: 34 ± 1 GPa; the post-shock temperature is 250 ± 50°C. The abundance and textural setting of localized melt products in these meteorites confirm increasing shock pressures in the sequence Shergotty, Zagami, EETA 79001, ALHA 77005. Undoubtedly, the melts could have been formed by the same single shock which produced the equilibrium shock effects (e.g.maskelynitization) in these meteorites. The shock-induced particle velocities inferred from Hugoniot data of basalts are in the 1.5–2.0 km/s range for the parental rocks of the shergottites. Ejection velocities are therefore in the order of 3–4 km/s. Special ejection mechanisms are required in order to exceed the escape velocity of a planet like Mars without producing higher degrees of shock (e.g.melting) than those observed in the shergottites.

Published
1986
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