@article{BergnerTrauthBookhagen2003,
  author    = {Bergner, Andreas G. N. and Trauth, Martin H. and Bookhagen, Bodo},
  title     = {Magnitude of precipitation : evaporation changes in the Naivasha Basin (Kenya) during the last 150 kyrs},
  year      = {2003},
  abstract  = {We modeled the two most extreme highstands of Lake Naivasha during the last 175 k.y. to estimate potential precipitation/ evaporation changes in this basin. In a first step, the bathymetry of the paleolakes at f135 and 9 k.y. BP was reconstructed from sediment cores and surface outcrops. Second, we modeled the paleohydrologic budget during the highstands using a simplified coupled energy mass-balance model. Our results show that the hydrologic and hence the climate conditions at f135 and 9 k.y. BP were similar, but significantly different from today. The main difference is a f15\% higher value in precipitation compared to the present. An adaptation and migration of vegetation in the cause of climate changes would result in a f30\% increase in precipitation. The most likely cause for such a wetter climate at f135 and 9 k.y. BP is a more intense intertropical convergence and increased precipitation in East Africa.},
  language  = {en}
}
@article{TrauthDeinoBergneretal.2003,
  author    = {Trauth, Martin H. and Deino, Alan and Bergner, Andreas G. N. and Strecker, Manfred},
  title     = {East African climate change and orbital forcing during the last 175 kyr BP},
  year      = {2003},
  abstract  = {Variations in the temporal and spatial distribution of solar radiation caused by orbital changes provide a partial explanation for the observed long-term fluctuations in African lake levels. The understanding of such relationships is essential for designing climate-prediction models for the tropics. Our assessment of the nature and timing of East African climate change is based on lake-level fluctuations of Lake Naivasha in the Central Kenya Rift (0°55'S 36°20'E), inferred from sediment characteristics, diatoms, authigenic mineral assemblages and 17 single-crystal 40Ar/39Ar age determinations. Assuming that these fluctuations reflect climate changes, the Lake Naivasha record demonstrates that periods of increased humidity in East Africa mainly followed maximum equatorial solar radiation in March or September. Interestingly, the most dramatic change in the Naivasha Basin occurred as early as 146 kyr BP and the highest lake level was recorded at about 139 to 133 kyr BP. This is consistent with other well-dated low-latitude climate records, but does not correspond to peaks in Northern Hemisphere summer insolation as the trigger for the ice- age cycles. The Naivasha record therefore provides evidence for low-latitude forcing of the ice-age climate cycles.},
  language  = {en}
}
@article{BergnerTrauth2004,
  author    = {Bergner, Andreas G. N. and Trauth, Martin H.},
  title     = {Comparison of the hydrologic and hydrochemical evolution of Lake Naivasha (Kenya) during three highstands between 175 and 60 kyr BP},
  year      = {2004},
  abstract  = {Three diatomite beds exposed in the Ol Njorowa Gorge south of Lake Naivasha, Central Kenya Rift, document three major lake-level highstands between 175 and 60 kyr BP. Diatom transfer-function estimates of hydrological and hydrochemical parameters suggest that a deep and large freshwater lake existed during the highstands at 135 and 80 kyr BP. In contrast, a shallower but more expanded freshwater lake existed at 110 kyr BP. The best analog for the most extreme highstand at 135 kyr BP is the highstand during the Early Holocene humid period from 10 to 6 kyr BP. The environmental conditions as reconstructed from diatom assemblages suggest long-lasting episodes of increased humidity during the high lake periods. This contrasts to the modern situation with a relatively shallow Lake Naivasha characterized by rapid water level fluctuations within a few decades. The most likely cause for the variable hydrological conditions since 175 kyr BP is orbitally driven insolation changes on the equator and increased lateral moisture transport from the ocean.},
  language  = {en}
}
@article{AsghariBroegCaroneetal.2004,
  author    = {Asghari, N. and Broeg, C. and Carone, L. and Casas-Miranda, R. and Palacio, J. C. C. and Csillik, I. and Dvorak, R. and Freistetter, F. and Hadjivantsides, G. and Hussmann, H. and Khramova, A. and Khristoforova, M. and Khromova, I. and Kitiashivilli, I. and Kozlowski, S. and Laakso, T. and Laczkowski, T. and Lytvinenko, D. and Miloni, O. and Morishima, R. and Moro-Martin, A. and Paksyutov, V. and Pal, A. and Patidar, V. and Pecnik, B. and Peles, O. and Pyo, J. and Quinn, T. and Rodriguez, A. and Romano, C. and Saikia, E. and Stadel, J. and Thiel, M. and Todorovic, N. and Veras, D. and Neto, E. V. and Vilagi, J. and von Bloh, Werner and Zechner, R. and Zhuchkova, E.},
  title     = {Stability of terrestrial planets in the habitable zone of G1 777 A, HD 72659, G1 614, 47 Uma and HD 4208},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361:20040390},
  year      = {2004},
  abstract  = {We have undertaken a thorough dynamical investigation of five extrasolar planetary systems using extensive numerical experiments. The systems Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208 were examined concerning the question of whether they could host terrestrial-like planets in their habitable zones (HZ). First we investigated the mean motion resonances between fictitious terrestrial planets and the existing gas giants in these five extrasolar systems. Then a fine grid of initial conditions for a potential terrestrial planet within the HZ was chosen for each system, from which the stability of orbits was then assessed by direct integrations over a time interval of 1 million years. For each of the five systems the 2-dimensional grid of initial conditions contained 80 eccentricity points for the Jovian planet and up to 160 semimajor axis points for the fictitious planet. The computations were carried out using a Lie-series integration method with an adaptive step size control. This integration method achieves machine precision accuracy in a highly efficient and robust way, requiring no special adjustments when the orbits have large eccentricities. The stability of orbits was examined with a determination of the Renyi entropy, estimated from recurrence plots, and with a more straightforward method based on the maximum eccentricity achieved by the planet over the 1 million year integration. Additionally, the eccentricity is an indication of the habitability of a terrestrial planet in the HZ; any value of e > 0.2 produces a significant temperature difference on a planet's surface between apoapse and periapse. The results for possible stable orbits for terrestrial planets in habitable zones for the five systems are: for Gl 777 A nearly the entire HZ is stable, for 47 Uma, HD 72659 and HD 4208 terrestrial planets can survive for a sufficiently long time, while for Gl 614 our results exclude terrestrial planets moving in stable orbits within the HZ. Studies such as this one are of primary interest to future space missions dedicated to finding habitable terrestrial planets in other stellar systems. Assessing the likelihood of other habitable planets, and more generally the possibility of other life, is the central question of astrobiology today. Our investigation indicates that, from the dynamical point of view, habitable terrestrial planets seem to be compatible with many of the currently discovered extrasolar systems},
  language  = {en}
}
@article{OliveiraelGueddariMoerschbacheretal.2008,
  author    = {Oliveira, Enio N. and el Gueddari, Nour E. and Moerschbacher, Bruno M. and Peter, Martin G. and Franco, Telma T.},
  title     = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides},
  issn      = {0301-486X},
  year      = {2008},
  abstract  = {Four phytopathogenic fungi were cultivated up to six days in media contg. chitooligosaccharide mixts. differing in av. DP and F A. The three different mixts. were named Q3 (which contained oligosaccharides of DP2-DP10, with DP2-DP7 as main components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixts. of oligosaccharides with different and known compn. on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concns. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concns. of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, resp. [on SciFinder (R)]},
  language  = {en}
}
@article{DuehnforthBergnerTrauth2008,
  author    = {D{\"u}hnforth, Miriam and Bergner, Andreas G. N. and Trauth, Martin H.},
  title     = {Early Holocene water budget of the Nakuru-Elmenteita basin, Central Kenya Rift},
  issn      = {0921-2728},
  doi       = {10.1007/s10933-006-9003-z},
  year      = {2008},
  language  = {en}
}
@article{RukungaMuregiOmaretal.2008,
  author    = {Rukunga, G. M. and Muregi, F. W. and Omar, S. A. and Gathirwa, J. W. and Muthaura, C. N. and Peter, Martin G.},
  title     = {Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus},
  issn      = {0367-326X},
  year      = {2008},
  abstract  = {Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.},
  language  = {en}
}
@article{TrauthMaslinDeinoetal.2008,
  author    = {Trauth, Martin H. and Maslin, Mark A. and Deino, Alan L. and Strecker, Manfred and Bergner, Andreas G. N. and D{\"u}hnforth, Miriam},
  title     = {High- and low-latitude forcing of Plio-Pleistocene African climate and human evolution},
  doi       = {10.1016/j.jhevol.2006.12.009},
  year      = {2008},
  abstract  = {The late Cenozoic climate of East Africa is punctuated by episodes of short, alternating periods of extreme wetness and aridity, superimposed on a regime of subdued moisture availability exhibiting a long-term drying trend. These periods of extreme climate variability appear to correlate with maxima in the 400-thousand-year (kyr) component of the Earth's eccentricity cycle. Prior to 2.7 Ma the wet phases appear every 400 kyrs, whereas after 2.7 Ma, the wet phases appear every 800 kyrs, with periods of precessional-forced extreme climate variability at 2.7-2.5 Ma, 1.9-1.7 Ma, and 1.1-0.9 Ma before present. The last three major lake phases occur at the times of major global climatic transitions, such as the onset of Northern Hemisphere Glaciation (2.7-2.5 Ma), intensification of the Walker Circulation (1.9-1.7 Ma), and the Mid-Pleistocene Revolution (1.0-0.7 Ma). High-latitude forcing is required to compress the Intertropical Convergence Zone so that East Africa becomes locally sensitive to precessional forcing, resulting in rapid shifts from wet to dry conditions. These periods of extreme climate variability may have provided a catalyst for evolutionary change and driven key speciation and dispersal events amongst mammals and hominins in East Africa. (C) 2007 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{YenesewTwinomuhweziKiremireetal.2009,
  author    = {Yenesew, Abiy and Twinomuhwezi, Hannington and Kiremire, Bernard T. and Mbugua, Martin N. and Gitu, Peter M. and Heydenreich, Matthias and Peter, Martin G.},
  title     = {8-Methoxyneorautenol and radical scavenging flavonoids from Erythrina abyssinica},
  issn      = {1011-3924},
  year      = {2009},
  abstract  = {A new pterocarpan (named 8-methoxyneorautenol) was isolated from the acetone ext. of the root bark of Erythrina abyssinica. In addn., the known isoflavonoid derivs. eryvarin L, erycristagallin and shinpterocarpin were identified for the first time from the roots of this plant. The structures were detd. on the basis of spectroscopic evidence. The new compd. showed selective antimicrobial activity against Trichophyton mentagrophytes. The acetone ext. of the root bark of E. abyssinica showed radical scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The pterocarpenes, 3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene and erycristagallin, were the most active constituents of the roots of this plant and showing dose-dependent activities similar to that of the std. quercetin. [on SciFinder (R)]},
  language  = {en}
}
@article{IssareeVijayakrishnanAbdelnuretal.2009,
  author    = {Issaree, Arisara and Vijayakrishnan, Balakumar and Abdelnur, Patricia V. and Corilo, Yuri E. and Riccio, Maria F. and Sanvido, Gustavo B. and Eberlin, Marcos N. and Peter, Martin G.},
  title     = {Mass spectrometry of aminoglucan oligosaccharides using electrospray ionization MS/MS and MS/MS/MS},
  year      = {2009},
  language  = {en}
}