Grenzsituationen als existenzielle Herausforderung

In seiner "Psychologie der Weltanschauungen" hat Karl Jaspers erstmals die seelischen Quellen und geistigen Typen der Weltanschauungen und der Philosophie aus psychologischer Sicht dargestellt. Ziel und Aufgabe seiner Untersuchung war es, zu verstehen, welche irreduziblen Grundkräfte die Seele bewegen, um das menschliche Leben auch noch in den Grenzsituationen bewältigen zu können. Dazu unterscheidet Jaspers zwischen Einstellungen, Weltbildern und Geistestypen als Elementen der jeweiligen Weltanschauung. Um das Leben des menschlichen Geistes zu verstehen, muss man nach Jaspers zwischen aktuellen Wertungen, abstrahierten Werten, persönlichen und kollektiven Wertehorizonten, situativen Wertekollisionen und diversen Wertehierachien unterscheiden. An Wertentscheidungen und Werturteilen sind nicht nur Gefühle, sondern auch der Verstand und der Wille beteiligt. Das Leiden ist der gemeinsame Grundzug aller Grenzsituationen, wie z.B. Kampf, Schuld und Tod, ist das Leiden der Menschen an etwas Unabänderlichen des menschlichen Daseins. In den Grenzsituationen kommt es nicht selten zu einem existenziellen Konflikt zwischen Hoffnung und Verzweiflung und verschiedene Geistestypen bedürfen eines existenziellen Haltes und letzten Grundes ihrer Existenz. Nach jaspers gibt es vier Typen der Reaktion auf die Grenzsituationen: Resignation, Weltflucht, Heroismus und Religiosität. Verbreiteter sind heute jedoch Versuche der Bewältigung durch Hedonismus und Konsumismus, die keinen letzten Halt bieten, sondern nur eine tiefere Verzweiflung kaschieren

Zur Frage nach dem Leiblichen bei Karl Jaspers

Obwohl Jaspers in seiner Philosophie Methoden und Motive der Phänomenologie Husserls und der Hermeneutik Diltheys aufgenommen hatte, hat er sich nicht besonders für die Leibphilosophie interessiert. Das bedeutet jedoch nicht, dass der menschliche Leib in seinem Denken gar nicht vorkommt. Aber es handelt sich bei ihm jedoch nicht um ein Schlüsselthema, sondern um ein randständiges Phänomen. Der menschliche Leib ist bei Jaspers die vitale Basis der überlieferten Trias von Leib, Seele und Geist. Damit steht Jaspers in der klassischen Traditionslinie des europäischen Denkens von Platon und Aristoteles bis zu Descartes und Kant. Anders als beim platonischen Sokrates gibt es bei Jaspers jedoch keine Herabsetzung des Körpers oder Abwertung des Leiblichen. Und anders als in der subversiven Tradition der empiristischen Skepsis gibt es bei ihm aber auch keine Vernachlässigung des Geistes. Im Vergleich des Menschen mit den Tieren ist der Geist nicht nur irgendein beliebiges, auf Sprache, Denken und Vernunft basierendes Merkmal, das den Menschen zufällig von den Tieren unterscheidet, sondern die wesentliche menschliche Eigenart, die es zu verstehen gilt, wenn man die spezifisch menschliche Art und Weise des Daseins in der Welt verstehen möchte, die Jaspers 'Existenz' nennt. Existenz zu verstehen ist die eigentliche Aufgabe der Philosophie, zumal die Wissenschaften dies nicht leisten können

Transgenerational temperature effects in the kelp Laminaria digitata

Transgenerational effects (effects of parental environment on offspring traits) have recently gained attention as a means of fast response to changing environmental conditions, e.g. under climate change. In temperate and polar rocky coastal ecosystems, kelps form the base of complexly structured and highly diverse species associations. This study investigates the potential for temperature-mediated transgenerational plasticity along the development from haploid parents (gametophytes) to their juvenile diploid offspring (sporophytes) in a geographically isolated population of the brown alga Laminaria digitata from the island of Helgoland (North Sea). We sampled spores from wild donor sporophytes, which we raised at 5 and 15 °C during gametogenesis, and reared the resulting young sporophytes for three months in a full-factorial split design while keeping genetic lineages separate. A concluding 12-day experiment on growth, biochemistry (carbon, mannitol content) and photosynthetic characteristics (maximum quantum yield Fv/Fm, maximum electron transport rate rETRmax) of five genetic lineages allowed for the separation of late temperature (12 day) responses, within-generation plasticity (early temperature) and transgenerational plasticity (gametogenesis temperature) in response to 5 and 15 °C. We observed significant two- and three-way interactions between gametogenesis temperature and early and late sporophyte temperatures for all parameters. While interactive effects between early and late experimental temperatures probably represent acclimation processes, interactions involving gametogenesis temperature indicate transgenerational effects. The direction of these effects differed between parameters. A main effect is that only with a history of 5 °C as gametogenesis and early temperature, sporophytes are growing faster at 5 than 15 °C over 12 days late temperature. According to our results, the temperature experienced by parents during gametogenesis influences temperature reaction norms in three- to four-month-old Laminaria digitata sporophytes. This, to our knowledge, is the first evidence for transgenerational plasticity in kelps

The critical exponents of the two-dimensional Ising spin glass revisited: Exact Ground State Calculations and Monte Carlo Simulations

The critical exponents for T -> 0 of the two-dimensional Ising spin glass model with Gaussian couplings are determined with the help of exact ground states for system sizes up to L=50 and by a Monte Carlo study of a pseudo-ferromagnetic order parameter. We obtain: for the stiffness exponent y(= heta)=-0.281 ±0.002 , for the magnetic exponent delta=1.48 ±0.01 and for the chaos exponent zeta=1.05 ±0.05 . From Monte Carlo simulations we get the thermal exponent u=3.6 ±0.2 . The scaling prediction y=-1/u is fulfilled within the error bars, whereas there is a disagreement with the relation y=1-delta

Incorporation of 14C-photosynthate into major chemical fractions of leaves and bark of Ceratonia siliqua L. at different seasons

Parts of branches of Ceratonia siliqua (L.) were exposed to 14CO2 for 3h during the growth period in April, after termination of growth (end of May), in the summer drought period (August) and in the cool winter (February). Twigs were harvested immediately after the end of the feeding period as well as after 48 and 144h. Simultaneously with the last harvest of exposed plant parts, controls from outside the exposure-chamber were also gathered. The total 14C-incorporation into leaves and bark as well as the labelling and contents of soluble sugars, starch, total lipids and other precipitable soluble compounds were determined. Total 14C-incorporation immediately after termination of 14CO2 application is a measure of the assimilation rate; it was high and nearly identical in April and May, but low (only about 5% of the April value) in summer ;and winter. The incorporation of 14C into soluble structural components was highest in April. Uptake of total 14C and labelling of soluble compounds during the 6-day period of the experiments show that metabolic rates were very low in summer but high during spring. The turnover of soluble compounds in February was remarkably high regarding the low CO2-fixation rate. The labelling of soluble sugars in leaves decreased in all experiments; the specific activity of starch remained rather stable. The incorporation of 14C into the lipid fraction was weak in all seasons and significant alterations took place only during the growing period. Variation in assimilation rates of Ceratonia at different seasons was comparable to that found for other mediterranean species using IRGA methods. There was no indication that lipids in Ceratonia are true storage compounds and participate in cyclic metabolic processes preventing stress effects. The weak turnover of lipids leads to the conclusion that maintenance costs for these compounds, as calculated by Merino et al. (1984). perhaps are too high, at least for Ceratonia. Our results do not suggest a specific adaptation of the metabolism of storage compounds to summer drought in Ceratonia

Thermal Plasticity of the Kelp Laminaria digitata (Phaeophyceae) Across Life Cycle Stages Reveals the Importance of Cold Seasons for Marine Forests

Phenotypic plasticity (genotype × environment interaction) is an especially important means for sessile organisms to cope with environmental variation. While kelps, the globally most productive group of seaweeds, generally possess a wide thermal performance range, kelp populations at their warm distribution limits are threatened by ocean warming. Here, we investigated effects of temperature during ontogeny of the kelp Laminaria digitata across haploid gametophyte and diploid sporophyte life cycle stages in five distinct genetic lines. We hypothesized that thermal plasticity increases trait performance of juvenile sporophytes in experimental temperatures that match the temperature experienced during gametogenesis and recruitment, and that plasticity differs among genetic lines (genetic variation for plasticity). We applied a full-factorial experimental design to generate different temperature histories by applying 5 and 15°C during meiospore germination, gametogenesis of parental gametophytes and recruitment of offspring sporophytes (19–26 days), and juvenile sporophyte rearing (91–122 days). We then tested for thermal plasticity among temperature history treatments at 5 and 15°C in a final 12-day experiment assessing growth, the storage compound mannitol, carbon and nitrogen contents, and fluorometric responses in 3–4 month old sporophytes for five genetic lines. Our study provides evidence for the importance of cold temperatures at early development on later sporophyte performance of L. digitata. Gametogenesis and recruitment at 5°C promoted higher growth of offspring sporophytes across experimental temperatures. While photosynthetic capacity was higher at 15°C, carbon and nitrogen storage were higher at 5°C, both showing fast acclimation responses. We identified an important role of genetic variation for plasticity in shaping L. digitata’s thermal plasticity. Trait performance at 5 or 15°C (reaction norm slopes) differed among genetic lines, even showing opposite response patterns. Interestingly, genetic variation for plasticity was only significant when sporophytes were reared at 5°C. Thus, we provide evidence that the cold-temperate to Arctic kelp species, L. digitata, which possesses a wide temperature tolerance between 0 and 23°C, is impaired by warm temperature during gametogenesis and recruitment, reducing growth of juvenile sporophytes and expression of variable thermal plasticity in the wild

Cycloadditions of Pentalene and Azulene—A Facile Heptalene Synthesis

The two lowest homologs of the annulene series, i. e. cyclobutadiene and benzene, are known to undergo either thermally or photochemically induced [2 +4] and [2 + 2] cycloadditions with reactive alkynes to give cyclobutene derivatives

Cycloadditionsreaktionen des Pentalens und Azulens – Eine einfache Heptalen-Synthese

Eine überraschend einfache Heptalen-Synthese besteht in der Umsetzung von Azulen (1) mit Acetylendicarbonsäure dimethylester. Die Ausbeute an (2) beträgt 15%. Die Synthese ist auch auf alkylierte Azulene anwendbar. Die detaillierte Struktur des Produktes (2) ergab sich aus einer Röntgenanalyse