@article{Leib2016, author = {Leib, Julia}, title = {Shaping peace: an investigation of the mechanisms underlying post-conflict peacebuilding}, series = {Peace, conflict \& development : an interdisciplinary journal}, journal = {Peace, conflict \& development : an interdisciplinary journal}, number = {22}, publisher = {Univ.}, address = {Bradford}, issn = {1742-0601}, pages = {25 -- 76}, year = {2016}, abstract = {What shapes peace, and how can peace be successfully built in those countries affected by armed conflict? This paper examines mpeacebuilding in the aftermath of civil wars in order to identify the conditions for post-conflict peace. The field of civil war research is characterised by case studies, comparative analyses and quantitative research, which relate relatively little to each other. Furthermore, the complex dynamics of peacebuilding have hardly been investigated so far. Thus, the question remains of how best to enhance the prospects of a stable peace in post-conflict societies. Therefore, it is necessary to capture the dynamics of post-conflict peace. This paper aims at helping to narrow these research gaps by 1) presenting the benefits of set theoretic methods for peace and conflict studies; 2) identifying remote conflict environment factors and proximate peacebuilding factors which have an influence on the peacebuilding process and 3) proposing a set-theoretic multi-method research approach in order to identify the causal structures and mechanisms underlying the complex realm of post-conflict peacebuilding. By implementing this transparent and systematic comparative approach, it will become possible to discover the dynamics of post-conflict peace.}, language = {en} } @article{AbseherMusliuWoltranetal.2016, author = {Abseher, Michael and Musliu, Nysret and Woltran, Stefan and Gebser, Martin and Schaub, Torsten H.}, title = {Shift Design with Answer Set Programming}, series = {Fundamenta informaticae}, volume = {147}, journal = {Fundamenta informaticae}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0169-2968}, doi = {10.3233/FI-2016-1396}, pages = {1 -- 25}, year = {2016}, abstract = {Answer Set Programming (ASP) is a powerful declarative programming paradigm that has been successfully applied to many different domains. Recently, ASP has also proved successful for hard optimization problems like course timetabling and travel allotment. In this paper, we approach another important task, namely, the shift design problem, aiming at an alignment of a minimum number of shifts in order to meet required numbers of employees (which typically vary for different time periods) in such a way that over- and understaffing is minimized. We provide an ASP encoding of the shift design problem, which, to the best of our knowledge, has not been addressed by ASP yet. Our experimental results demonstrate that ASP is capable of improving the best known solutions to some benchmark problems. Other instances remain challenging and make the shift design problem an interesting benchmark for ASP-based optimization methods.}, language = {en} } @article{VorburgerNedielkovBrosigetal.2016, author = {Vorburger, Thomas and Nedielkov, Ruslan and Brosig, Alexander and Bok, Eva and Schunke, Emina and Steffen, Wojtek and Mayer, Sonja and Goetz, Friedrich and M{\"o}ller, Heiko Michael and Steuber, Julia}, title = {Role of the Na+-translocating NADH:quinone oxidoreductase in voltage generation and Na+ extrusion in Vibrio cholerae}, series = {Biochimica et biophysica acta : Bioenergetics}, volume = {1857}, journal = {Biochimica et biophysica acta : Bioenergetics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0005-2728}, doi = {10.1016/j.bbabio.2015.12.010}, pages = {473 -- 482}, year = {2016}, abstract = {For Vibrio cholerae, the coordinated import and export of Na+ is crucial for adaptation to habitats with different osmolarities. We investigated the Na+-extruding branch of the sodium cycle in this human pathogen by in vivo Na-23-NMR spectroscopy. The Na+ extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). In a V. cholerae deletion mutant devoid of the Na+-NQR encoding genes (nqrA-F), rates of respiratory Na+ extrusion were decreased by a factor of four, but the cytoplasmic Na+ concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (Delta psi, inside negative) and did not grow under hypoosmotic conditions at pH 8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na+/H+ antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na+ concentrations, the Na+-NQR is crucial for generation of a transmembrane voltage to drive the import of H+ by electrogenic Na+/H+ antiporters. Our study provides the basis to understand the role of the Na+-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na+ pump for respiration. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} } @article{KistnerVollmeyerBurnsetal.2016, author = {Kistner, Saskia and Vollmeyer, Regina and Burns, Bruce D. and Kortenkamp, Ulrich}, title = {Model development in scientific discovery learning with a computer-based physics task}, series = {Computers in human behavior}, volume = {59}, journal = {Computers in human behavior}, publisher = {Elsevier}, address = {Oxford}, issn = {0747-5632}, doi = {10.1016/j.chb.2016.02.041}, pages = {446 -- 455}, year = {2016}, abstract = {Based on theories of scientific discovery learning (SDL) and conceptual change, this study explores students' preconceptions in the domain of torques in physics and the development of these conceptions while learning with a computer-based SDL task. As a framework we used a three-space theory of SDL and focused on model space, which is supposed to contain the current conceptualization/model of the learning domain, and on its change through hypothesis testing and experimenting. Three questions were addressed: (1) What are students' preconceptions of torques before learning about this domain? To do this a multiple-choice test for assessing students' models of torques was developed and given to secondary school students (N = 47) who learned about torques using computer simulations. (2) How do students' models of torques develop during SDL? Working with simulations led to replacement of some misconceptions with physically correct conceptions. (3) Are there differential patterns of model development and if so, how do they relate to students' use of the simulations? By analyzing individual differences in model development, we found that an intensive use of the simulations was associated with the acquisition of correct conceptions. Thus, the three-space theory provided a useful framework for understanding conceptual change in SDL.}, language = {en} } @article{SinclairBussideVilliersetal.2016, author = {Sinclair, Nathalie and Bussi, Maria G. Bartolini and de Villiers, Michael and Jones, Keith and Kortenkamp, Ulrich and Leung, Allen and Owens, Kay}, title = {Recent research on geometry education: an ICME-13 survey team report}, series = {ZDM : The International Journal on Mathematics Education}, volume = {48}, journal = {ZDM : The International Journal on Mathematics Education}, publisher = {Springer}, address = {Heidelberg}, issn = {1863-9690}, doi = {10.1007/s11858-016-0796-6}, pages = {691 -- 719}, year = {2016}, abstract = {This survey on the theme of Geometry Education (including new technologies) focuses chiefly on the time span since 2008. Based on our review of the research literature published during this time span (in refereed journal articles, conference proceedings and edited books), we have jointly identified seven major threads of contributions that span from the early years of learning (pre-school and primary school) through to post-compulsory education and to the issue of mathematics teacher education for geometry. These threads are as follows: developments and trends in the use of theories; advances in the understanding of visuo spatial reasoning; the use and role of diagrams and gestures; advances in the understanding of the role of digital technologies; advances in the understanding of the teaching and learning of definitions; advances in the understanding of the teaching and learning of the proving process; and, moving beyond traditional Euclidean approaches. Within each theme, we identify relevant research and also offer commentary on future directions.}, language = {en} } @article{KistnerBurnsVollmeyeretal.2016, author = {Kistner, Saskia and Burns, Bruce D. and Vollmeyer, Regina and Kortenkamp, Ulrich}, title = {The importance of understanding: Model space moderates goal specificity effects}, series = {The quarterly journal of experimental psychology}, volume = {69}, journal = {The quarterly journal of experimental psychology}, publisher = {Optical Society of America}, address = {Abingdon}, issn = {1747-0218}, doi = {10.1080/17470218.2015.1076865}, pages = {1179 -- 1196}, year = {2016}, abstract = {The three-space theory of problem solving predicts that the quality of a learner's model and the goal specificity of a task interact on knowledge acquisition. In Experiment 1 participants used a computer simulation of a lever system to learn about torques. They either had to test hypotheses (nonspecific goal), or to produce given values for variables (specific goal). In the good- but not in the poor-model condition they saw torque depicted as an area. Results revealed the predicted interaction. A nonspecific goal only resulted in better learning when a good model of torques was provided. In Experiment 2 participants learned to manipulate the inputs of a system to control its outputs. A nonspecific goal to explore the system helped performance when compared to a specific goal to reach certain values when participants were given a good model, but not when given a poor model that suggested the wrong hypothesis space. Our findings support the three-space theory. They emphasize the importance of understanding for problem solving and stress the need to study underlying processes.}, language = {en} } @article{KortenkampMonaghanTrouche2016, author = {Kortenkamp, Ulrich and Monaghan, John and Trouche, Luc}, title = {Jonathan M Borwein (1951-2016): exploring, experiencing and experimenting in mathematics - an inspiring journey in mathematics}, series = {Educational studies in mathematics : an international journal}, volume = {93}, journal = {Educational studies in mathematics : an international journal}, publisher = {Springer}, address = {Dordrecht}, issn = {0013-1954}, doi = {10.1007/s10649-016-9729-0}, pages = {131 -- 136}, year = {2016}, language = {en} } @article{SoemerSaito2016, author = {Soemer, Alexander and Saito, Satoru}, title = {Domain-specific processing in short-term serial order memory}, series = {Journal of memory and language}, volume = {88}, journal = {Journal of memory and language}, publisher = {Elsevier}, address = {San Diego}, issn = {0749-596X}, doi = {10.1016/j.jml.2015.12.003}, pages = {1 -- 17}, year = {2016}, abstract = {Recent studies of short-term serial order memory have suggested that the maintenance of order information does not involve domain-specific processes. We carried out two dual task experiments aimed at resolving several ambiguities in those studies. In our experiments, encoding and response of one serial reconstruction task was embedded within encoding and response of a concurrent serial reconstruction task. Order demands in both tasks were independently varied so as to find revealing patterns of interference between the two tasks. In Experiment 1, participants were to maintain and reconstruct the order of a list of verbal materials, while maintaining a list of spatial materials or vice-versa. Increasing the order demands in the outer reconstruction task resulted in small or non reliable performance decrements in the embedded reconstruction task. Experiment 2 sought to compare these results against two same-domain baseline conditions (two verbal lists or two spatial lists). In all conditions, increasing order demands in the outer task resulted in small or non-reliable performance decrements in the embedded task. However, performance in the embedded tasks was generally lower in the same-domain baseline conditions than in the cross-domain conditions. We argue that the main effect of domain in Experiment 2 indicates the contribution of domain-specific processes to short-term serial order maintenance. In addition, we interpret the failure to find consistent cross-list interference irrespective of domain as indicating the involvement of grouping mechanisms in concurrently performed serial order tasks. (C) 2015 Elsevier Inc. All rights reserved.}, language = {en} } @article{SoemerSchwan2016, author = {Soemer, Alexander and Schwan, Stephan}, title = {Task-Appropriate Visualizations: Can the Very Same Visualization Format Either Promote or Hinder Learning Depending on the Task Requirements?}, series = {The journal of educational psychology}, volume = {108}, journal = {The journal of educational psychology}, publisher = {American Psychological Association}, address = {Washington}, issn = {0022-0663}, doi = {10.1037/edu0000093}, pages = {960 -- 968}, year = {2016}, abstract = {In a series of experiments, we tested a recently proposed hypothesis stating that the degree of alignment between the form of a mental representation resulting from learning with a particular visualization format and the specific requirements of a learning task determines learning performance (task-appropriateness). Groups of participants were required to learn the stroke configuration, the stroke order, or the stroke directions of a set of Chinese pseudocharacters. For each learning task, participants were divided into groups receiving dynamic, static-sequential, or static visualizations. An old/new character recognition task was given at test. The results showed that learning both stroke configuration and stroke order was best with static pictures (Experiments 1 and 2), while there was no reliable difference between the groups for learning stroke direction (Experiment 3). An additional experiment, however, revealed that learning with sequential pictures was superior when testing was carried out with sequential pictures, irrespective of the learning task (Experiment 4). The combined evidence from all experiments speaks against task requirements playing a role in determining the effectiveness of a visualization format. Furthermore, the evidence supports the view that a high degree of congruence between information presented during learning and information presented at test results in better learning (study-test congruence). Implications for instructional design are discussed.}, language = {en} } @article{LyTarkhanov2016, author = {Ly, Ibrahim and Tarkhanov, Nikolai Nikolaevich}, title = {A Rado theorem for p-harmonic functions}, series = {Boletin de la Sociedad Matem{\~A}!'tica Mexicana}, volume = {22}, journal = {Boletin de la Sociedad Matem{\~A}!'tica Mexicana}, publisher = {Springer}, address = {Basel}, issn = {1405-213X}, doi = {10.1007/s40590-016-0109-7}, pages = {461 -- 472}, year = {2016}, abstract = {Let A be a nonlinear differential operator on an open set X subset of R-n and S a closed subset of X. Given a class F of functions in X, the set S is said to be removable for F relative to A if any weak solution of A(u) = 0 in XS of class F satisfies this equation weakly in all of X. For the most extensively studied classes F, we show conditions on S which guarantee that S is removable for F relative to A.}, language = {en} } @article{WalterHamannLuecketal.2016, author = {Walter, J. and Hamann, G{\"o}ran and L{\"u}ck, Erika and Klingenfuss, C. and Zeitz, Jutta}, title = {Stratigraphy and soil properties of fens: Geophysical case studies from northeastern Germany}, series = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution}, volume = {142}, journal = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0341-8162}, doi = {10.1016/j.catena.2016.02.028}, pages = {112 -- 125}, year = {2016}, abstract = {The determination of the total carbon storage of peatlands is of high relevance in the context of climate-change mitigation efforts. This determination relies on data about stratigraphy and peat properties, which are conventionally collected by coring. Ground-penetrating radar (GPR) and electrical resistivity imaging (ERI) can support these point data by providing subsoil information in two-dimensional cross-sections. In this study, GPR and ERI were conducted at two groundwater-fed fen sites located in the temperate zone in north-east Germany. The fens of this region are embedded in low conductive glacial sand and are characterised by thick layers of gyttja, which can be either mineral or organic. The two study sites are representative of this region with respect to stratigraphy (total thickness, peat and gyttja types) and ecological conditions (pH-value, trophic condition). The aim of this study is to assess the suitability of GPR and ERI to detect stratigraphy and peat properties under these characteristic site conditions. Results show that GPR clearly detects the interfaces between (i) Carex and brown-moss peat, (ii) brown-moss peat and organic gyttja, (iii) organic- and mineral gyttja, and (iv) mineral gyttja and the parent material (glacial sand). These layers differ in bulk density and the related organic matter content. ERI, however, does not delineate these layers; rather it delineates regions of varying properties. At our base-rich site, pore fluid conductivity and cation.exchange capacity are the main factors that determine peat electrical conductivity (reverse of resistivity), whereas organic matter and water content are most influential at the more acidic site. Thus the correlation between peat properties and electrical conductivity are driven by site-specific conditions, which are mainly determined by the solute load in the groundwater at fens. When the total organic deposits exceed a thickness of 5 m, the depth of investigation by GPR is limited due to increasing attenuation. This is not a limiting factor for ERI, where the transition from organic deposits to glacial sand is visible at both sites. Due to these specific sensitivities, a combined application of GPR and ERI meets the demand for up-to-date information on carbon storage of peatlands, which is, moreover, very site-specific because of the inherent variety of ecological conditions and stratigraphy between peatlands in general and between fens and bogs in particular. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{ReyesVazquezZeidaetal.2016, author = {Reyes, Anibal M. and Vazquez, Diego S. and Zeida, Ari and Hugo, Martin and Dolores Pineyro, M. and Ines De Armas, Maria and Estrin, Dario and Radi, Rafael and Santos, Javier and Trujillo, Madia}, title = {PrxQ B from Mycobacterium tuberculosis is a monomeric, thioredoxin-dependent and highly efficient fatty acid hydroperoxide reductase}, series = {Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research}, volume = {101}, journal = {Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research}, publisher = {Elsevier}, address = {New York}, issn = {0891-5849}, doi = {10.1016/j.freeradbiomed.2016.10.005}, pages = {249 -- 260}, year = {2016}, abstract = {Mycobacterium tuberculosis (M. tuberculosis) is the intracellular bacterium responsible for tuberculosis disease (TD). Inside the phagosomes of activated macrophages, M. tuberculosis is exposed to cytotoxic hydroperoxides such as hydrogen peroxide, fatty acid hydroperoxides and peroxynitrite. Thus, the characterization of the bacterial antioxidant systems could facilitate novel drug developments. In this work, we characterized the product of the gene Rv1608c from M. tuberculosis, which according to sequence homology had been annotated as a putative peroxiredoxin of the peroxiredoxin Q subfamily (PrxQ B from M. tuberculosis or MtPrxQ B). The protein has been reported to be essential for M. tuberculosis growth in cholesterol-rich medium. We demonstrated the M. tuberculosis thioredoxin B/C-dependent peroxidase activity of MtPrxQ B, which acted as a two-cysteine peroxiredoxin that could function, although less efficiently, using a one-cysteine mechanism. Through steady-state and competition kinetic analysis, we proved that the net forward rate constant of MtPrxQ B reaction was 3 orders of magnitude faster for fatty acid hydroperoxides than for hydrogen peroxide (3x10(6) vs 6x10(3) M-1 s(-1), respectively), while the rate constant of peroxynitrite reduction was (0.6-1.4) x10(6) M-1 s(-1) at pH 7.4. The enzyme lacked activity towards cholesterol hydroperoxides solubilized in sodium deoxycholate. Both thioredoxin B and C rapidly reduced the oxidized form of MtPrxQ B, with rates constants of 0.5x10(6) and 1x10(6) M-1 s(-1), respectively. Our data indicated that MtPrxQ B is monomeric in solution both under reduced and oxidized states. In spite of the similar hydrodynamic behavior the reduced and oxidized forms of the protein showed important structural differences that were reflected in the protein circular dichroism spectra.}, language = {en} } @article{HoehleBergerSauermann2016, author = {H{\"o}hle, Barbara and Berger, Frauke and Sauermann, Antje}, title = {Information structure in first language acquisition}, series = {The Oxford handbook of information structure}, journal = {The Oxford handbook of information structure}, publisher = {Oxford University Press}, address = {Oxford}, isbn = {978-0-19-964267-0}, pages = {562 -- 580}, year = {2016}, language = {en} } @article{Klinnert2016, author = {Klinnert, Anne}, title = {Rohstoffpolitik im 21. Jahrhundert}, series = {WeltTrends : das außenpolitische Journal}, volume = {24}, journal = {WeltTrends : das außenpolitische Journal}, number = {118}, publisher = {WeltTrends}, address = {Potsdam}, isbn = {978-3-945878-25-5}, issn = {0944-8101}, pages = {24 -- 29}, year = {2016}, abstract = {In den 2000er-Jahren stiegen die Rohstoffpreise enorm an. Ausl{\"o}ser waren die wirtschaftliche Entwicklung der Schwellenl{\"a}nder, allen voran Chinas, sowie der gestiegene Rohstoffbedarf durch technologische Innovationen. Diese „Rohstoffkrise" ver{\"a}nderte das Verh{\"a}ltnis der Rohstoff exportierenden und importierenden Staaten zueinander. Auch wird Rohstoffpolitik nicht mehr nur unter wirtschaftlichen, sondern ebenso unter {\"o}kologischen und sozialen Kriterien betrachtet. Der Beitrag erl{\"a}utert die Ursachen und benennt Auswirkungen der Krise.}, language = {de} } @article{KruegerKellingSchildeetal.2016, author = {Kr{\"u}ger, Tobias and Kelling, Alexandra and Schilde, Uwe and Linker, Torsten}, title = {Simple Synthesis of gamma-Spirolactams by Birch Reduction of Benzoic Acids}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {6}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201601650}, pages = {1074 -- 1077}, year = {2016}, abstract = {A convenient synthesis of gamma-spirolactams in only two steps was developed. Birch reduction of benzoic acids and immediate alkylation with chloroacetonitrile afforded cyclohexadienes in high yields. The products could be isolated by crystallization on a large scale in analytically pure form. Subsequent hydrogenation with platinum(IV) oxide as the catalyst reduced the nitrile functionality and the double bonds in the same step with excellent stereoselectivity. The relative configurations were determined unequivocally by X-ray analyses. Direct cyclization of the intermediary formed amino acids afforded the desired gamma-spirolactams in excellent overall yields. The procedure is characterized by few steps, cheap reagents, and can be performed on a large scale, interesting for industrial processes.}, language = {en} } @article{Kunow2016, author = {Kunow, R{\"u}diger}, title = {Postcolonial theory and old age: An explorative essay}, series = {Journal of aging studie}, volume = {39}, journal = {Journal of aging studie}, publisher = {Elsevier}, address = {New York}, issn = {0890-4065}, doi = {10.1016/j.jaging.2016.06.004}, pages = {101 -- 108}, year = {2016}, language = {en} } @article{DrummervanderMeerSchaadt2016, author = {Drummer, Janna-Deborah and van der Meer, Elke and Schaadt, Gesa}, title = {Event-related potentials in response to violations of content and temporal event knowledge}, series = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience}, volume = {80}, journal = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience}, publisher = {Elsevier}, address = {Oxford}, issn = {0028-3932}, doi = {10.1016/j.neuropsychologia.2015.11.007}, pages = {47 -- 55}, year = {2016}, abstract = {Scripts that store knowledge of everyday events are fundamentally important for managing daily routines. Content event knowledge (i.e., knowledge about which events belong to a script) and temporal event knowledge (i.e., knowledge about the chronological order of events in a script) constitute qualitatively different forms of knowledge. However, there is limited information about each distinct process and the time course involved in accessing content and temporal event knowledge. Therefore, we analyzed event-related potentials (ERPs) in response to either correctly presented event sequences or event sequences that contained a content or temporal error. We found an N400, which was followed by a posteriorly distributed P600 in response to content errors in event sequences. By contrast, we did not find an N400 but an anteriorly distributed P600 in response to temporal errors in event sequences. Thus, the N400 seems to be elicited as a response to a general mismatch between an event and the established event model. We assume that the expectancy violation of content event knowledge, as indicated by the N400, induces the collapse of the established event model, a process indicated by the posterior P600. The expectancy violation of temporal event knowledge is assumed to induce an attempt to reorganize the event model in working memory, a process indicated by the frontal P600. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{MetzTielboerger2016, author = {Metz, Johannes and Tielboerger, Katja}, title = {Spatial and temporal aridity gradients provide poor proxies for plant-plant interactions under climate change: a large-scale experiment}, series = {Functional ecology : an official journal of the British Ecological Society}, volume = {30}, journal = {Functional ecology : an official journal of the British Ecological Society}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0269-8463}, doi = {10.1111/1365-2435.12599}, pages = {20 -- 29}, year = {2016}, abstract = {1. Plant-plant interactions may critically modify the impact of climate change on plant communities. However, the magnitude and even direction of potential future interactions remains highly debated, especially for water-limited ecosystems. Predictions range from increasing facilitation to increasing competition with future aridification. 2. The different methodologies used for assessing plant-plant interactions under changing environmental conditions may affect the outcome but they are not equally represented in the literature. Mechanistic experimental manipulations are rare compared with correlative approaches that infer future patterns from current observations along spatial climatic gradients. 3. Here, we utilize a unique climatic gradient in combination with a large-scale, long-term experiment to test whether predictions about plant-plant interactions yield similar results when using experimental manipulations, spatial gradients or temporal variation. We assessed shrub-annual interactions in three different sites along a natural rainfall gradient (spatial) during 9 years of varying rainfall (temporal) and 8 years of dry and wet manipulations of ambient rainfall (experimental) that closely mimicked regional climate scenarios. 4. The results were fundamentally different among all three approaches. Experimental water manipulations hardly altered shrub effects on annual plant communities for the assessed fitness parameters biomass and survival. Along the spatial gradient, shrub effects shifted from clearly negative to mildly facilitative towards drier sites, whereas temporal variation showed the opposite trend: more negative shrub effects in drier years. 5. Based on our experimental approach, we conclude that shrub-annual interaction will remain similar under climate change. In contrast, the commonly applied space-for-time approach based on spatial gradients would have suggested increasing facilitative effects with climate change. We discuss potential mechanisms governing the differences among the three approaches. 6. Our study highlights the critical importance of long-term experimental manipulations for evaluating climate change impacts. Correlative approaches, for example along spatial or temporal gradients, may be misleading and overestimate the response of plant-plant interactions to climate change.}, language = {en} } @article{BiltonMetzTielboerger2016, author = {Bilton, Mark C. and Metz, Johannes and Tielboerger, Katja}, title = {Climatic niche groups: A novel application of a common assumption predicting plant community response to climate change}, series = {Perspectives in plant ecology, evolution and systematics}, volume = {19}, journal = {Perspectives in plant ecology, evolution and systematics}, publisher = {Elsevier}, address = {Jena}, issn = {1433-8319}, doi = {10.1016/j.ppees.2016.02.006}, pages = {61 -- 69}, year = {2016}, abstract = {Defining species by their climatic niche is the simple and intuitive principle underlying Bioclimatic Envelope Model (BEM) predictions for climate change effects. However, these correlative models are often criticised for neglecting many ecological processes. Here, we apply the same niche principle to entire communities within a medium/long-term climate manipulation study, where ecological processes are inherently included. In a nine generation study in Israel, we manipulated rainfall (Drought -30\%; Irrigation +30\%; Control natural rainfall) at two sites which differ chiefly in rainfall quantity and variability. We analysed community responses to the manipulations by grouping species based on their climatic rainfall niche. These responses were compared to analyses based on single species, total densities, and commonly used taxonomic groupings. Climate Niche Groups yielded clear and consistent results: within communities, those species distributed in drier regions performed relatively better in the drought treatment, and those from wetter climates performed better when irrigated. In contrast, analyses based on other principles revealed little insight into community dynamics. Notably, most relationships were weaker at the drier, more variable site, suggesting that enhanced adaptation to variability may buffer climate change impacts. We provide robust experimental evidence that using climatic niches commonly applied in BEMs is a valid approach for eliciting community changes in response to climate change. However, we also argue that additional empirical information needs to be gathered using experiments in situ to correctly assess community vulnerability. Climatic Niche Groups used in this way, may therefore provide a powerful tool and directional testing framework to generalise and compare climate change impacts across habitats. (C) 2016 The Authors. Published by Elsevier GmbH.}, language = {en} } @article{RauchQuinetHoyeretal.2016, author = {Rauch, Thomas and Quinet, P. and Hoyer, D. and Werner, K. and Richter, Philipp and Kruk, J. W. and Demleitner, M.}, title = {VII. New Kr IV - VII oscillator strengths and an improved spectral analysis of the hot, hydrogen-deficient DO-type white dwarf RE 0503-289}, series = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, volume = {590}, journal = {Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants}, publisher = {EDP Sciences}, address = {Les Ulis}, organization = {VERITAS Collaboration}, issn = {1432-0746}, doi = {10.1051/0004-6361/201628131}, pages = {26}, year = {2016}, abstract = {Context. For the spectral analysis of high-resolution and high signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Aims. New Kr IV-VII oscillator strengths for a large number of lines enable us to construct more detailed model atoms for our NLTE model-atmosphere calculations. This enables us to search for additional Kr lines in observed spectra and to improve Kr abundance determinations. Methods. We calculated Kr IV-VII oscillator strengths to consider radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models for the analysis of Kr lines that are exhibited in high-resolution and high S/N ultraviolet (UV) observations of the hot white dwarf RE 0503-289. Results. We reanalyzed the effective temperature and surface gravity and determined T-eff = 70 000 +/- 2000 K and log (g/cm s(-2)) = 7.5 +/- 0.1. We newly identified ten Kr V lines and one Kr vi line in the spectrum of RE 0503-289. We measured a Kr abundance of 3.3 +/- 0.3 (logarithmic mass fraction). We discovered that the interstellar absorption toward RE 0503-289 has a multi-velocity structure within a radial-velocity interval of -40 km s(-1) < upsilon(rad) < +18 km s(-1). Conclusions. Reliable measurements and calculations of atomic data are a prerequisite for state-of-the-art NLTE stellar-atmosphere modeling. Observed Kr V-VII line profiles in the UV spectrum of the white dwarf RE 0503-289 were simultaneously well reproduced with our newly calculated oscillator strengths.}, language = {en} }