@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{KoenigAblerAgartzetal.2020, author = {Koenig, Julian and Abler, Birgit and Agartz, Ingrid and akerstedt, Torbjorn and Andreassen, Ole A. and Anthony, Mia and Baer, Karl-Juergen and Bertsch, Katja and Brown, Rebecca C. and Brunner, Romuald and Carnevali, Luca and Critchley, Hugo D. and Cullen, Kathryn R. and de Geus, Eco J. C. and de la Cruz, Feliberto and Dziobek, Isabel and Ferger, Marc D. and Fischer, Hakan and Flor, Herta and Gaebler, Michael and Gianaros, Peter J. and Giummarra, Melita J. and Greening, Steven G. and Guendelman, Simon and Heathers, James A. J. and Herpertz, Sabine C. and Hu, Mandy X. and Jentschke, Sebastian and Kaess, Michael and Kaufmann, Tobias and Klimes-Dougan, Bonnie and Koelsch, Stefan and Krauch, Marlene and Kumral, Deniz and Lamers, Femke and Lee, Tae-Ho and Lekander, Mats and Lin, Feng and Lotze, Martin and Makovac, Elena and Mancini, Matteo and Mancke, Falk and Mansson, Kristoffer N. T. and Manuck, Stephen B. and Mather, Mara and Meeten, Frances and Min, Jungwon and Mueller, Bryon and Muench, Vera and Nees, Frauke and Nga, Lin and Nilsonne, Gustav and Ordonez Acuna, Daniela and Osnes, Berge and Ottaviani, Cristina and Penninx, Brenda W. J. H. and Ponzio, Allison and Poudel, Govinda R. and Reinelt, Janis and Ren, Ping and Sakaki, Michiko and Schumann, Andy and Sorensen, Lin and Specht, Karsten and Straub, Joana and Tamm, Sandra and Thai, Michelle and Thayer, Julian F. and Ubani, Benjamin and van Der Mee, Denise J. and van Velzen, Laura S. and Ventura-Bort, Carlos and Villringer, Arno and Watson, David R. and Wei, Luqing and Wendt, Julia and Schreiner, Melinda Westlund and Westlye, Lars T. and Weymar, Mathias and Winkelmann, Tobias and Wu, Guo-Rong and Yoo, Hyun Joo and Quintana, Daniel S.}, title = {Cortical thickness and resting-state cardiac function across the lifespan}, series = {Psychophysiology : journal of the Society for Psychophysiological Research}, volume = {58}, journal = {Psychophysiology : journal of the Society for Psychophysiological Research}, number = {7}, publisher = {Wiley}, address = {Hoboken}, issn = {0048-5772}, doi = {10.1111/psyp.13688}, pages = {16}, year = {2020}, abstract = {Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5\% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.}, 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{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} } @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{PereiraNascimentoMagalhaesetal.2014, author = {Pereira, Fernanda S. and Nascimento, Heliara D. L. and Magalhaes, Alvicler and Peter, Martin G. and Bataglion, Giovana Anceski and Eberlin, Marcos N. and Gonzalez, Eduardo R. P.}, title = {ESI(+)-MS and GC-MS study of the hydrolysis of N-azobenzyl derivatives of chitosan}, series = {Molecules}, volume = {19}, journal = {Molecules}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules191117604}, pages = {17604 -- 17618}, year = {2014}, abstract = {New N-p-chloro-, N-p-bromo-, and N-p-nitrophenylazobenzylchitosan derivatives, as well as the corresponding azophenyl and azophenyl-p-sulfonic acids, were synthesized by coupling N-benzylvchitosan with aryl diazonium salts. The synthesized molecules were analyzed by UV-Vis, FT-IR, H-1-NMR and N-15-NMR spectroscopy. The capacity of copper chelation by these materials was studied by AAS. Chitosan and the derivatives were subjected to hydrolysis and the products were analyzed by ESI(+)-MS and GC-MS, confirming the formation of N-benzyl chitosan. Furthermore, the MS results indicate that a nucleophilic aromatic substitution (SnAr) reaction occurs under hydrolysis conditions, yielding chloroaniline from N-p-bromo-, and N-p-nitrophenylazo-benzylchitosan as well as bromoaniline from N-p-chloro-, and N-p-nitrophenylazobenzyl-chitosan.}, language = {en} } @article{VijayakrishnanIssareeCoriloetal.2011, author = {Vijayakrishnan, Balakumar and Issaree, Arisara and Corilo, Yuri E. and Ferreira, Christina Ramires and Eberlin, Marcos N. and Peter, Martin G.}, title = {MSn of the six isomers of (GlcN)(2)(GlcNAc)(2) aminoglucan tetrasaccharides (diacetylchitotetraoses) rules of fragmentation for the sodiated molecules and application to sequence analysis of hetero-chitooligosaccharides}, series = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, volume = {84}, journal = {Carbohydrate polymers : an international journal devoted to scientific and technological aspects of industrially important polysaccharides}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2010.04.041}, pages = {713 -- 726}, year = {2011}, abstract = {The six possible isomers of di-N-acetylchitotetraoses [AADD, ADDA, ADAD, DADA, DAAD, and DDAA, where D stands for 2-amino-2-deoxy-3-D-glucose (GlcN) and A for 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc)] were analyzed by ESI(+)-MSn. Collision induced dissociation via MSn experiments were performed for the sodiated molecules of m/z 769 [M+Na](+) for each isomer, and fragments were generated mainly by glycosidic bond and cross-ring cleavages. Rules of fragmentation were then established. A reducing end D residue yields the (O.2)A(4) cross-ring [M-59+Na](+) fragment of m/z 710 as the most abundant, whereas isomers containing a reducing end A prefer to lose water to form the [M-18+Na](+) ion of m/z 751, as well as abundant (O.2)A(4) cross-ring [M-101+Na](+) fragments of m/z 668 and B-3 [M-221+Na](+) ions of m/z 548. MS3 of C- and Y-type ions shows analogous fragmentation behaviour that allows identification of the reducing end next-neighbour residue. Due to gas-phase anchimeric assistance, B-type cleavage between the glycosidic oxygen and the anomeric carbon atom is favoured when the glycon is an A residue. Relative ion abundances are generally in the order B >> C > Y, but may vary depending on the next neighbour towards the non-reducing end. These fragmentation rules were used for partial sequence analysis of hetero-chitooligosaccharides of the composition D(2)A(3), D(3)A(3), D(2)A(4), D(4)A(3), and D(3)A(4).}, language = {en} } @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{BergnerStreckerTrauthetal.2009, author = {Bergner, Andreas G. N. and Strecker, Manfred and Trauth, Martin H. and Deino, Alan L. and Gasse, Francoise and Blisniuk, Peter Michael and Duehnforth, Miriam}, title = {Tectonic and climatic control on evolution of rift lakes in the Central Kenya Rift, East Africa}, issn = {0277-3791}, doi = {10.1016/j.quascirev.2009.07.008}, year = {2009}, abstract = {The long-term histories of the neighboring Nakuru-Elmenteita and Naivasha lake basins in the Central Kenya Rift illustrate the relative importance of tectonic versus climatic effects on rift-lake evolution and the formation of disparate sedimentary environments. Although modem climate conditions in the Central Kenya Rift are very similar for these basins, hydrology and hydrochemistry of present-day lakes Nakuru, Elmenteita and Naivasha contrast dramatically due to tectonically controlled differences in basin geometries, catchment size, and fluvial processes. In this study, we use eighteen C-14 and Ar-40/Ar-39 dated fluvio-lacustrine sedimentary sections to unravel the spatiotemporal evolution of the lake basins in response to tectonic and climatic influences. We reconstruct paleoclimatic and ecological trends recorded in these basins based on fossil diatom assemblages and geologic field mapping. Our study shows a tendency towards increasing alkalinity and shrinkage of water bodies in both lake basins during the last million years. Ongoing volcano-tectonic segmentation of the lake basins, as well as reorganization of upstream drainage networks have led to contrasting hydrologic regimes with adjacent alkaline and freshwater conditions. During extreme wet periods in the past, such as during the early Holocene climate optimum, lake levels were high and all basins evolved toward freshwater systems. During drier periods some of these lakes revert back to alkaline conditions, while others maintain freshwater characteristics. Our results have important implications for the use and interpretation of lake sediment as climate archives in tectonically active regions and emphasize the need to deconvolve lacustrine records with respect to tectonics versus climatic forcing mechanisms.}, 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} }