TY  - JOUR
A1  - Ohl, Sven
A1  - Brandt, Stephan A.
A1  - Kliegl, Reinhold
T1  - The generation of secondary saccades without postsaccadic visual feedback
JF  - Journal of vision
N2  - Primary saccades are often followed by small secondary saccades, which are generally thought to reduce the distance between the saccade endpoint and target location. Accumulated evidence demonstrates that secondary saccades are subject to various influences, among which retinal feedback during postsaccadic fixation constitutes only one important signal. Recently, we reported that target eccentricity and an orientation bias influence the generation of secondary saccades. In the present study, we examine secondary saccades in the absence of postsaccadic visual feedback. Although extraretinal signals (e.g., efference copy) have received widespread attention in eye-movement studies, it is still unclear whether an extraretinal error signal contributes to the programming of secondary saccades. We have observed that secondary saccade latency and amplitude depend on primary saccade error despite the absence of postsaccadic visual feedback. Strong evidence for an extraretinal error signal influencing secondary saccade programming is given by the observation that secondary saccades are more likely to be oriented in a direction opposite to the primary saccade as primary saccade error shifts from target undershoot to overshoot. We further show how the functional relationship between primary saccade landing position and secondary saccade characteristics varies as a function of target eccentricity. We propose that initial target eccentricity and an extraretinal error signal codetermine the postsaccadic activity distribution in the saccadic motor map when no visual feedback is available.
KW  - monocular deprivation
KW  - binocular combination
KW  - sensory balance
Y1  - 2013
U6  - https://doi.org/10.1167/13.5.11
SN  - 1534-7362
VL  - 13
IS  - 5
PB  - Association for Research in Vision and Opthalmology
CY  - Rockville
ER  - 
TY  - JOUR
A1  - Bindschadler, Robert A.
A1  - Nowicki, Sophie
A1  - Abe-Ouchi, Ayako
A1  - Aschwanden, Andy
A1  - Choi, Hyeungu
A1  - Fastook, Jim
A1  - Granzow, Glen
A1  - Greve, Ralf
A1  - Gutowski, Gail
A1  - Herzfeld, Ute
A1  - Jackson, Charles
A1  - Johnson, Jesse
A1  - Khroulev, Constantine
A1  - Levermann, Anders
A1  - Lipscomb, William H.
A1  - Martin, Maria A.
A1  - Morlighem, Mathieu
A1  - Parizek, Byron R.
A1  - Pollard, David
A1  - Price, Stephen F.
A1  - Ren, Diandong
A1  - Saito, Fuyuki
A1  - Sato, Tatsuru
A1  - Seddik, Hakime
A1  - Seroussi, Helene
A1  - Takahashi, Kunio
A1  - Walker, Ryan
A1  - Wang, Wei Li
T1  - Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea level (the SeaRISE project)
JF  - Journal of glaciology
N2  - Ten ice-sheet models are used to study sensitivity of the Greenland and Antarctic ice sheets to prescribed changes of surface mass balance, sub-ice-shelf melting and basal sliding. Results exhibit a large range in projected contributions to sea-level change. In most cases, the ice volume above flotation lost is linearly dependent on the strength of the forcing. Combinations of forcings can be closely approximated by linearly summing the contributions from single forcing experiments, suggesting that nonlinear feedbacks are modest. Our models indicate that Greenland is more sensitive than Antarctica to likely atmospheric changes in temperature and precipitation, while Antarctica is more sensitive to increased ice-shelf basal melting. An experiment approximating the Intergovernmental Panel on Climate Change's RCP8.5 scenario produces additional first-century contributions to sea level of 22.3 and 8.1 cm from Greenland and Antarctica, respectively, with a range among models of 62 and 14 cm, respectively. By 200 years, projections increase to 53.2 and 26.7 cm, respectively, with ranges of 79 and 43 cm. Linear interpolation of the sensitivity results closely approximates these projections, revealing the relative contributions of the individual forcings on the combined volume change and suggesting that total ice-sheet response to complicated forcings over 200 years can be linearized.
Y1  - 2013
U6  - https://doi.org/10.3189/2013JoG12J125
SN  - 0022-1430
VL  - 59
IS  - 214
SP  - 195
EP  - 224
PB  - International Glaciological Society
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Wiemann, Dirk
T1  - Cities of the mind - villages of the mind
BT  - imagining urbanity in Contemporary India
JF  - Zeitschrift für Anglistik und Amerikanistik : a quarterly of language, literature and cultur
N2  - Deep into the second half of the twentieth century the traditionalist definition of India as a country of villages remained dominant in official political rhetoric as well as cultural production. In the past two decades or so, this ruralist paradigm has been effectively superseded by a metropolitan imaginary in which the modern, globalised megacity increasingly functions as representative of India as a whole. Has the village, then, entirely vanished from the cultural imaginary in contemporary India? Addressing economic practices from upper-class consumerism to working-class family support strategies, this paper attempts to trace how 'the village' resurfaces or survives as a cultural reference point in the midst of the urban.
Y1  - 2013
U6  - https://doi.org/10.1515/zaa.2013.61.1.59
SN  - 0044-2305
VL  - 61
IS  - 1
SP  - 59
EP  - 72
PB  - Königshausen & Neumann
CY  - Würzburg
ER  - 
TY  - JOUR
A1  - Nottebrock, Henning
A1  - Esler, Karen J.
A1  - Schurr, Frank Martin
T1  - Effects of intraspecific and community density on the lifetime fecundity of long-lived shrubs
JF  - Perspectives in plant ecology, evolution and systematics
N2  - Intra- and interspecific density dependence has profound consequences for plant population and community dynamics. In long-lived plants, however, lifetime patterns and mechanisms of density dependence are difficult to study. Here, we examine effects of intraspecific and community density on the lifetime fecundity of two long-lived shrub species from South African Fynbos: Protea repens (animal-pollinated, hermaphroditic) and Leucadendron rubrum (wind-pollinated, dioecious). Both species are serotinous, retaining seeds in cones until fire kills the mother plant. We measured lifetime fecundity as the product of cone number, proportion of cones that are not damaged by predation and seed set (fertile seeds per intact cone). Intraspecific and community densities were quantified by counting individuals of target species and all Proteaceae in small- and large-scale neighbourhoods (10 m and 50 m radius) around each focal individual. Additionally, we determined the age and size of focal individuals. We found that lifetime fecundity of the wind-pollinated L rubrum is density independent. In contrast, the lifetime fecundity of the animal-pollinated P. repens increases with large-scale intraspecific density and shows a hump-shaped relationship to large-scale community density. Community density has a hump-shaped effect on seed set (probably through partial absence of generalized pollinators at low and competition for pollinators at high densities) and negatively affects cone number per individual. For both species, plant age decreases seed set while increasing lifetime fecundity. The qualitative differences in the density dependence of lifetime fecundity may arise from differences between animal and wind pollination. In particular, interactions with generalized animal pollinators may cause community-level Allee effects with profound consequences for the future dynamics of long-lived plant populations and communities.
KW  - Competition
KW  - Community-level Allee effects
KW  - Facilitation
KW  - Fitness components
KW  - Interspecific interactions
KW  - Plant-animal interactions
Y1  - 2013
U6  - https://doi.org/10.1016/j.ppees.2013.03.003
SN  - 1433-8319
VL  - 15
IS  - 3
SP  - 150
EP  - 161
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Junginger, Mathias
A1  - Kübel, Christian
A1  - Schacher, Felix H.
A1  - Müller, Axel H. E.
A1  - Taubert, Andreas
T1  - Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers
JF  - RSC Advances
N2  - Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano) diffraction, energy-dispersive X-ray spectroscopy, and energy-filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.
Y1  - 2013
U6  - https://doi.org/10.1039/c3ra23348k
SN  - 2046-2069
VL  - 3
IS  - 28
SP  - 11301
EP  - 11308
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Liang, Wei
A1  - Heinrich, Ingo
A1  - Helle, Gerhard
A1  - Linan, Isabel Dorado
A1  - Heinken, Thilo
T1  - Applying CLSM to increment core surfaces for histometric analyses a novel advance in quantitative wood anatomy
JF  - Dendrochronologia : an interdisciplinary journal of tree-ring science
N2  - A novel procedure has been developed to conduct cell structure measurements on increment core samples of conifers. The procedure combines readily available hardware and software equipment. The essential part of the procedure is the application of a confocal laser scanning microscope (CLSM) which captures images directly from increment cores surfaced with the advanced WSL core-microtome. Cell wall and lumen are displayed with a strong contrast due to the monochrome black and green nature of the images. Consecutive images are merged into long images representing entire increment cores which are then analysed for cell structures in suitable software.
KW  - Wood anatomy
KW  - Cell structures
KW  - Confocal laser scanning microscopy
KW  - CLSM
KW  - Dendrochronology
KW  - Surface preparation
Y1  - 2013
U6  - https://doi.org/10.1016/j.dendro.2012.09.002
SN  - 1125-7865
VL  - 31
IS  - 2
SP  - 140
EP  - 145
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Conradt, Tobias
A1  - Wechsung, F.
A1  - Bronstert, Axel
T1  - Three perceptions of the evapotranspiration landscape comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances
JF  - Hydrology and earth system sciences : HESS
N2  - A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km(2)) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash-Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interior points revealed large deviations. Therefore, we compared three different strategies for deriving sub-basin evapotranspiration: (1) modelled by SWIM without any spatial calibration, (2) derived from remotely sensed surface temperatures, and (3) calculated from long-term precipitation and discharge data. The results show certain consistencies between the modelled and the remote sensing based evapotranspiration rates, but there seems to be no correlation between remote sensing and water balance based estimations. Subsequent analyses for single sub-basins identify amongst others input weather data and systematic error amplification in inter-gauge discharge calculations as sources of uncertainty. The results encourage careful utilisation of different data sources for enhancements in distributed hydrological modelling.
Y1  - 2013
U6  - https://doi.org/10.5194/hess-17-2947-2013
SN  - 1027-5606
VL  - 17
IS  - 7
SP  - 2947
EP  - 2966
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Sommer, Michael
A1  - Jochheim, H.
A1  - Höhn, Axel
A1  - Breuer, Jörn
A1  - Zagorski, Z.
A1  - Busse, J.
A1  - Barkusky, Dietmar
A1  - Meier, K.
A1  - Puppe, D.
A1  - Wanner, Manfred
A1  - Kaczorek, Danuta
T1  - Si cycling in a forest biogeosystem - the importance of transient state biogenic Si pools
JF  - Biogeosciences
N2  - The relevance of biological Si cycling for dissolved silica (DSi) export from terrestrial biogeosystems is still in debate. Even in systems showing a high content of weatherable minerals, like Cambisols on volcanic tuff, biogenic Si (BSi) might contribute > 50% to DSi (Gerard et al., 2008). However, the number of biogeosystem studies is rather limited for generalized conclusions. To cover one end of controlling factors on DSi, i.e., weatherable minerals content, we studied a forested site with absolute quartz dominance (> 95 %). Here we hypothesise minimal effects of chemical weathering of silicates on DSi. During a four year observation period (05/2007-04/2011), we quantified (i) internal and external Si fluxes of a temperate-humid biogeosystem (beech, 120 yr) by BIOME-BGC (version ZALF), (ii) related Si budgets, and (iii) Si pools in soil and beech, chemically as well as by SEM-EDX. For the first time two compartments of biogenic Si in soils were analysed, i.e., phytogenic and zoogenic Si pool (testate amoebae). We quantified an average Si plant uptake of 35 kg Si ha(-1) yr(-1) - most of which is recycled to the soil by litterfall - and calculated an annual biosilicification from idiosomic testate amoebae of 17 kg Si ha(-1). The comparatively high DSi concentrations (6 mg L-1) and DSi exports (12 kg Si ha(-1) yr(-1)) could not be explained by chemical weathering of feldspars or quartz dissolution. Instead, dissolution of a relictic, phytogenic Si pool seems to be the main process for the DSi observed. We identified canopy closure accompanied by a disappearance of grasses as well as the selective extraction of pine trees 30 yr ago as the most probable control for the phenomena observed. From our results we concluded the biogeosystem to be in a transient state in terms of Si cycling.
Y1  - 2013
U6  - https://doi.org/10.5194/bg-10-4991-2013
SN  - 1726-4170
VL  - 10
IS  - 7
SP  - 4991
EP  - 5007
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Solly, Emily
A1  - Schöning, Ingo
A1  - Boch, Steffen
A1  - Mueller, J.
A1  - Socher, S. A.
A1  - Trumbore, S. E.
A1  - Schrumpf, M.
T1  - Mean age of carbon in fine roots from temperate forests and grasslands with different management
JF  - Biogeosciences
N2  - Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C) inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (C-14) content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 +/- 0.8 g (mean +/- SE, n = 27) than in forests 3.1 +/- 0.5 g (n = 27) (p < 0.05), the mean age of C in fine roots in forests averaged 11.3 +/- 1.8 yr and was older and more variable compared to grasslands 1.7 +/- 0.4 yr (p < 0.001). We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated with plant diversity (r = 0.65) and with the number of perennial species (r = 0.77). Fine root mean C age in grasslands was also affected by study region with averages of 0.7 +/- 0.1 yr (n= 9) on mostly organic soils in northern Germany and of 1.8 +/- 0.3 yr (n = 9) and 2.6 +/- 0.3 (n = 9) in central and southern Germany (p < 0.05). This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.
Y1  - 2013
U6  - https://doi.org/10.5194/bg-10-4833-2013
SN  - 1726-4170
VL  - 10
IS  - 7
SP  - 4833
EP  - 4843
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Thete, Aniket
A1  - Rojas, Oscar
A1  - Neumeyer, David
A1  - Koetz, Joachim
A1  - Dujardin, Erik
T1  - Ionic liquid-assisted morphosynthesis of gold nanorods using polyethyleneimine-capped seeds
JF  - RSC Advances
N2  - Seed-mediated gold nanorods with tunable lengths are prepared using new polyethyleneimine-capped gold nanoparticles synthesized in ionic liquid. The effect of polyethyleneimine and ionic liquid during nanorod growth is investigated and shows a marked effect on their final aspect ratio.
Y1  - 2013
U6  - https://doi.org/10.1039/c3ra22112a
SN  - 2046-2069
VL  - 3
IS  - 34
SP  - 14294
EP  - 14298
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -