Swiss tree rings reveal warm and wet summers during medieval times

We present a 1200 year drought reconstruction for the European Alpine region based on carbon isotope variations of tree rings from living larch trees and historic timber. The carbon isotope fractionation at the study site is sensitive to summer precipitation, temperature, and irradiance, resulting in a stable and high correlation with a drought index for interannual to decadal frequencies and possibly beyond (r(2)=0.58 for 1901-2004, July/August). When combining this information with maximum latewood density-derived summer temperature, a strongly reduced occurrence of summer droughts during the warm A.D. 900-1200 period is evident, coinciding with the Medieval Climate Anomaly (MCA), with a shift to colder and drier conditions for the subsequent centuries. The warm-wet MCA contrasts strongly with the climate of the drought-prone warm phase of the recent decades, indicating different forcing mechanism for these two warm periods and pointing to beneficial conditions for agriculture and human well-being during the MCA in this region.

Rings um Jerusalem

von Hans Much

Chemistry of pyrrocorphins: methylative opening of the macrocycle between rings A and D, a side reaction in the peripheral C-methylation of a 20-methyl-pyrrocorphinate

One of the minor products from the previously described peripheral -methylation of a magnesium()-20-methyl--pyrrocorphinate is a C-19-methylated 19,20-seco-corphinoid derivative which, on complexation with nickel() acetate, recyclizes to a nickel()-tetradehydro-corrinate.

Chemistry of pyrrocorphins: synthesis of isobacteriochlorins and pyrrocorphins bearing a methyl group at the meso position between rings A and D

A sigmatropic methyl shift from the angular position C-1 in ring to the position C-20 between rings and constitutes the crucial step in syntheses leading to a 20-methyl-isobacteriochlorin and to 20-methyl-pyrrocorphins which served as substrates in the investigation presented in the accompanying communication.

Crop Yield Responses to Temperature Fluctuations in 19th Century Finland: Provincial Variation in Relation to Climate and Tree Rings

Past agricultural responses to climate variability can helps us to better understand the current and future impacts of climate change on agricultural production. We studied rye (Secale cereale) and barley (Hordeum vulgare) yield responses to temperature fluctuations in Finland during the period 1861–1913. Our analyses demonstrate the high sensitivity of non-industrialised northern agriculture to temperature anomalies. We found evidence of a strong relationship between monthly and seasonal mean temperatures and crop yields. In particular, high spring temperatures were associated with higher yields. Additionally, we tested temperature-sensitive tree-ring series for their value in indicating previous agricultural outputs. The results imply that tree-ring proxies (in particular, maximum latewood density) can provide novel material for studies of historical periods and locations where instrumentally measured climate and harvest data are not available.

Petition der Herren Schusterjungen Münchens an den Magistrat daselbst: Hoher und stellenweiser sehr vortrefflicher Magistrat! Während rings um uns herum diejenigen Bürger, welche sich in den großen Tagen des Februar und März ...

Welsch (Projektbearbeiter): Ätzende Satire von konservativ/reaktionärer Seite auf den Verlauf der Münchener Märzrevolution in Form einer Petition der Schusterjungen zwecks Anerkennung ihrer Verdienste

Stable carbon and oxygen isotopes in tree rings show physiological responses of Pericopsis elata to precipitation in the Congo Basin

In equatorial regions, where tree rings are less distinct or even absent, the response of forests to high-frequency climate variability is poorly understood. We measured stable carbon and oxygen isotopes in anatomically distinct, annual growth rings of four Pericopsis elata trees from a plantation in the Congo Basin, to assess their sensitivity to recorded changes in precipitation over the last 50 y. Our results suggest that oxygen isotopes have high common signal strength (EPS = 0.74), and respond to multi-annual precipitation variability at the regional scale, with low δ18O values (28–29‰) during wetter conditions (1960–1970). Conversely, δ13C are mostly related to growth variation, which in a light-demanding species are driven by competition for light. Differences in δ13C values between fast- and slow-growing trees (c. 2‰), result in low common signal strength (EPS = 0.37) and are driven by micro-site conditions rather than by climate. This study highlights the potential for understanding the causes of growth variation in P. elata as well as past hydroclimatic changes, in a climatically complex region characterized by a bimodal distribution in precipitation.

Concepción heroica Homérica en The Lord of the rings

Fil: Pepe de Suárez, Luz E. A..

Homero y Tolkien. Resonancias homéricas en 'The Lord of the Rings', de Luz Pepe de Suárez

Fil: Errecalde, Alejandro Martín. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Homero y Tolkien. Resonancias homéricas en 'The Lord of the Rings', de Luz Pepe de Suárez

Fil: Errecalde, Alejandro Martín. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Homero y Tolkien. Resonancias homéricas en 'The Lord of the Rings', de Luz Pepe de Suárez

Fil: Errecalde, Alejandro Martín. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.