Refine
Has Fulltext
- no (1887) (remove)
Year of publication
- 2017 (1887) (remove)
Document Type
- Article (1397)
- Doctoral Thesis (168)
- Other (117)
- Part of a Book (93)
- Review (52)
- Monograph/Edited Volume (46)
- Conference Proceeding (6)
- Habilitation Thesis (4)
- Journal/Publication series (2)
- Contribution to a Periodical (1)
Is part of the Bibliography
- yes (1887)
Keywords
- stars: massive (11)
- Germany (10)
- Holocene (9)
- German (8)
- climate change (8)
- stars: early-type (8)
- adolescence (7)
- stars: winds, outflows (7)
- Arabidopsis (6)
- Arabidopsis thaliana (6)
Institute
- Institut für Biochemie und Biologie (330)
- Institut für Geowissenschaften (254)
- Institut für Physik und Astronomie (251)
- Institut für Chemie (131)
- Department Psychologie (117)
- Department Sport- und Gesundheitswissenschaften (86)
- Institut für Ernährungswissenschaft (69)
- Department Linguistik (52)
- Institut für Mathematik (52)
- Institut für Romanistik (49)
Taming Nuclear Power
(2017)
In 2011 a broad majority in the German Federal Parliament voted to abandon nuclear energy. This article explores the origins of the change in attitude towards nuclear energy and argues that seven years before the Chernobyl disaster, the accident at the U.S. power plant Three Mile Island near Harrisburg, Pennsylvania, in 1979, had a profound impact which nowadays seems to be largely forgotten in Europe. The article identifies the structural causes underlying the transnational reception of the Three Mile Island accident and explores international reactions, particularly in the Federal Republic of Germany. The accident near Harrisburg led to a loss of public confidence and created unease about nuclear expansion in many industrialized nations. Reactions to the accident can be understood as an attempt to tame nuclear energy both technically, by increasing safety measures and abandoning plans for new nuclear power stations, and politically, with a more critical appraisal of nuclear energy and with semantics that encouraged a long-term withdrawal from nuclear power. Critics were now also accepted as experts. Nuclear policy in all countries became closely dependent on public opinion, indicating a high level of political responsiveness. Various factors, however, including the contemporaneous oil crisis put the brakes on this critical approach to nuclear power, while safety improvements and the limited expansion of nuclear power created new confidence in the early 1980s.
The Misho complex in Northwest Iran is a prominent topographic massif bounded by well known active faults. Our new structural analysis of this area indicates that faulting has important role in the exhumation of this complex. The conjugate orientation of the North and South Misho Faults caused uplift in the Misho and exhumation of the Precambrian crystalline basement. Our structural and stratigraphic data shows that rapid uplift could have been initiation since the 21-22 Ma and exhumation rate was about 0.16 to 0.24 km/Ma. To refine this age, we performed U/Pb analysis of detrital zircon from the Upper Red Formation using LA-ICP-MS. We conducted AFT analysis on 6 basement samples from the hanging wall and 1 sample from the Upper Red Formation in the footwall NMF. Uplift in the hanging wall of NMF led to resting of sample 916 marl. This geochronologic and thermochronologic data shows that exhumation in the MC is diachronously along strike and affected by faults. The phase of exhumation is documented in the study area and entire Iranian plateau is related to the final closure of the Neo-Tethys and northward motion of the Arabian Plate.
This two-wave longitudinal study identified configurations of social rejection, affiliation with aggressive peers, and academic failure and examined their predictivity for reactive and proactive aggression in a sample of 1,479 children and adolescents aged between 9 and 19 years. Latent profile analysis yielded three configurations of risk factors, made up of a non-risk group, a risk group scoring high on measures of social rejection (SR), and a risk group scoring high on measures of affiliation with aggressive peers and academic failure (APAF). Latent path analysis revealed that, as predicted, only membership in the SR group at T1 predicted reactive aggression at T2 17 months later. By contrast, only membership in the APAF group at T1 predicted proactive aggression at T2.
Form and Content, Again
(2017)
The following statement suggests reconsidering recent debates on a theory of lyric in terms of form and content. Four aspects and issues of the ongoing debate are discussed. In a first step, it is necessary to establish the relation between authorial poetics and lyric theory, since it is often characterised by fuzzy boundaries. Secondly, in order to specify the problem of form in lyric theory, it is suggested to have a closer look at the performative in lyric practice. Another important aspect of form is the semantics of lyrical genres. Lyrical genres mark an area in which form and content are intertwined and in which aspects of the form itself become semantic. Finally, the author argues that we should discuss - if possible assisted by a didactics sensitive to literary texts - whether and how theoretical proposals could be transformed into a practice of teaching poetry.
The crystallization kinetics of silicate liquids were studied experimentally in the system haplogranite-B-Li-H2O, at variable degrees of undercooling and variable water concentration. We investigated the kinetics of nucleation and crystallization of unseeded synthetic hydrous haplogranite with 1 wt % Li2O + 2 center dot 3 wt % B2O3 added (composition C1) and 2 wt % Li2O + 4 center dot 6 wt % B2O3 added (composition C2). Compositions C1 and C2 are simplified representative bulk compositions of Li-rich pegmatites and their highly differentiated cores, respectively. Starting water contents varied between 3 and 9 wt %. With few exceptions, the system remained water-undersaturated. About 86 isothermal runs of 1-60 days duration, grouped in 25 time series of constant temperature and initial H2O content, were carried out at temperatures from 400 to 700A degrees C at 300 MPa, corresponding to variable degrees of undercooling between the liquidus and glass transition. Viscosity measurements indicate that the glass transition for both compositions is below 400A degrees C for 3 wt % water and below 300A degrees C for 6 center dot 5 wt % water. The melts remained virtually crystal free at 400A degrees C, about 100A degrees C and 120A degrees C above the glass transition for compositions C1 and C2, respectively, in experiments up to 30 days long. This result is consistent with the existence of low-temperature, undercooled melts in the crust. At lower values of undercooling the runs crystallized partially, up to about 70% volume fraction. Undercooling and the amount of water are the main factors controlling nucleation and growth rates, and therefore textures. Minerals nucleate and grow sequentially according to mineral-specific nucleation delays. The mineral assemblage started with Li-Al stuffed quartz (in C1) and virgilite (in C2), solid-solutions between quartz and gamma-spodumene. The quartz-like phases were typically followed by spherulitic alkali feldspar-quartz intergrowths, euhedral petalite, and fine-grained muscovite. Nearly pure quartz formed as rims and replacement of metastable virgilite and stuffed quartz, in particular at the boron- and water-rich crystallization front of large feldspar or petalite. With the exception of muscovite, all minerals nucleated heterogeneously, on the capsule wall or on pre-existing minerals, and grew inwards, towards the capsule center. Experimental textures resembled the textures of zoned pegmatites, including skeletal, graphic, unidirectional, radiating, spherulitic, massive, and replacement textures. In some cases, when fluid saturation was reached, miarolitic cavities developed containing euhedral crystals. Although unidirectional growth rates appeared to slow down in time, volumetric rates for stable graphic alkali-feldspar quartz intergrowths and petalite remained constant for up to 60 days and similar to 70% crystallization. Metastable stuffed quartz and virgilite diminished in their growth rates in runs of 30 days or longer, were resorbed in the melt, and were partially replaced by second-generation quartz. Unobstructed, self-sustained crystal growth in conditions of very low nucleation density appears to be the dominant mechanism to form giant pegmatitic crystals, although experimental growth rates are much slower than predicted in nature based on conductive-cooling models.
The early Cretaceous Paraná–Etendeka Large Igneous Province is attributed to the impact of the Tristan mantle plume on the base of the continental lithosphere and the associated opening of the South Atlantic Ocean during the breakup of West Gondwana. Although the geochemistry of the Paraná and Etendeka volcanic rocks has been extensively studied, there is still disagreement on the role of the mantle plume in the production of the magma types observed, because some of their primary compositions are obscured by continental crustal contamination. However, there are related plutonic rocks that preserve mantle signatures. The Doros Complex is a shallow-level mafic intrusion within the Etendeka Province of Namibia. New 39Ar/40Ar step-heating ages for Doros gabbros from this study (weighted mean of 130 ± 1 Ma; 2σ error) confirm contemporaneity with the Paraná–Etendeka magmatic event. The Doros suite yields mean ɛNd values of +5·3 ± 1·0 (1σ; n = 11), initial 87Sr/86Sr = 0·70418 ± 0·00017 (n = 11) and 206Pb/204Pb = 18·11 ± 0·06 (n = 13) at 132 Ma. The clustering of isotopic data and trends in incompatible trace element ratios indicate that all the magmas in the complex were derived from the same mantle source components, during the same melting episode. By quantitative isotopic modelling of mixing processes, we constrain the Doros parental magma to comprise 60–80% melt of a depleted asthenospheric mantle component and 20–40% melt of a more enriched, Tristan plume-derived, asthenospheric component. No lithospheric mantle component is required to explain the Doros magma compositions. The chilled margin to the complex is the only rock type that shows evidence of significant continental crustal contamination, by assimilation of the metasedimentary host-rock upon emplacement. The identification of a substantial Tristan plume component in the Doros source confirms the integral role of the deep-seated thermal anomaly in Paraná–Etendeka magmatism. We show, in addition, that the Doros suite has consistent, strong geochemical affinities with the Tafelkop group ‘ferropicrite’ lavas of the Etendeka Province. This provides crucial evidence in support of Doros as the eruptive site for the Tafelkop lavas, thereby linking the Doros magmatism to the earliest eruptive phase in the Etendeka event. The distinctive chemistry of this magma group has been attributed to relatively deep decompression melting of pyroxenite-bearing material in the heterogeneous Tristan plume head, related to the initial impact of the plume on the base of the lithosphere.
Root infinitives on Twitter
(2017)
The acentriolar Dictyostelium centrosome is a nucleus-associated body consisting of a core structure with three plaque-like layers, which are surrounded by a microtubule-nucleating corona. The core duplicates once per cell cycle at the G2/M transition, whereby its central layer disappears and the two outer layers form the mitotic spindle poles. Through proteomic analysis of isolated centrosomes, we have identified CP39 and CP75, two essential components of the core structure. Both proteins can be assigned to the central core layer as their centrosomal presence is correlated to the disappearance and reappearance of the central core layer in the course of centrosome duplication. Both proteins contain domains with centrosome-binding activity in their N- and C-terminal halves, whereby the respective N-terminal half is required for cell cycle-dependent regulation. CP39 is capable of self-interaction and GFP-CP39 overexpression elicited supernumerary microtubule-organizing centers and pre-centrosomal cytosolic clusters. Underexpression stopped cell growth and reversed the MTOC amplification phenotype. In contrast, in case of CP75 underexpression of the protein by RNAi treatment elicited supernumerary MTOCs. In addition, CP75RNAi affects correct chromosome segregation and causes co-depletion of CP39 and CP91, another central core layer component. CP39 and CP75 interact with each other directly in a yeast two-hybrid assay. Furthermore, CP39, CP75 and CP91 mutually interact in a proximity-dependent biotin identification (BioID) assay. Our data indicate that these three proteins are all required for proper centrosome biogenesis and make up the major structural components of core structure's central layer.
Wings of the butterfly
(2017)
The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826-1867) and Sporer (1866-1880). The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30 degrees-45 degrees) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20 degrees-30 degrees) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2 degrees-10 degrees) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer.
Two nuclear explosions were carried out by the Democratic People’s Republic of North Korea in January and September 2016. Epicenters were located close to those of the 2006, 2009, and 2013 previous explosions. We perform a seismological analysis of the 2016 events combining the analysis of full waveforms at regional distances and seismic array beams at teleseismic distances. We estimate the most relevant source parameters, such as source depth, moment release, and full moment tensor (MT). The best MT solution can be decomposed into an isotropic source, directly related with the explosion and an additional deviatoric term, likely due to near‐source interactions with topographic and/or underground facilities features. We additionally perform an accurate resolution test to assess source parameters uncertainties and trade‐offs. This analysis sheds light on source parameters inconsistencies among studies on previous shallow explosive sources. The resolution of the true MT is hindered by strong source parameters trade‐offs, so that a broad range of well‐fitting MT solutions can be found, spanning from a dominant positive isotropic term to a dominant negative vertical compensated linear vector dipole. The true mechanism can be discriminated by additionally modeling first‐motion polarities at seismic arrays at teleseismic distances. A comparative assessment of the 2016 explosion with earlier nuclear tests documents similar vertical waveforms but a significant increase of amplitude for the 2016 explosions, which proves that the 9 September 2016 was the largest nuclear explosion ever performed in North Korea with a magnitude Mw 4.9 and a shallow depth of less than 2 km, although there are no proofs of a fusion explosion. Modeling transversal component waveforms suggests variable size and orientation of the double‐couple components of the 2009, 2013, and 2016 sources.