A multi‐dimensional analysis of the impacts of the Mahatma Gandhi National Rural Employment Guarantee Scheme: A tale from Tamil Nadu

This paper provides a multi‐dimensional analysis of the impacts of the Indian Mahatma Gandhi National Rural Employment Guarantee Scheme using a case study from rural Tamil Nadu. Drawing on structured interviews in households and semi‐structured interviews with local employers and officials, we analyse the effects of the workfare scheme when it is widely and properly implemented. We distinguish between different conceptualizations of the work scheme as a means of welfare provision, labour market policy and intervention directed towards other objectives. We found that the goals of the scheme were fulfilled unevenly in the given context. Among other findings, we show that positive effects on the welfare of participating and non‐participating households were accompanied by adverse effects on the local economy and negligible impact on out‐migration for work.     

Der Chemismus oberdevoniseher Flaserkalke des Gaisberges bei Graz

Ohne Zusammenfassung     

Vegetation re-establishment in polar "lichen-kill" landscapes: a case study of the Little Ice Age impact

It has been accepted that the extremely sparse vegetation currently observed in Canadian polar deserts is due to prevailing unfavourable climatic conditions, inhibiting plant establishment, growth and survival. Less considered in the literature is the additional antagonistic factor of episodic adverse climatic anomalies. Such was the most recent Little Ice Age (LIA) cooling which caused a setback to, or even largescale extinction of, high Arctic plant communities that had taken centuries to develop. The LIA brought about new glacial advances, expansion of permanent snow banks and formation of ice crusts over entire landscapes. The newly formed ice (and snow) killed the underlying vegetation, thus creating what is in the geological literature referred to as "lichen-kill zones." In these zones the current plant diversity and abundance are exceedingly low and the plants are all relatively young and even-aged, factors which all point to their recent origin. Here we maintain that this vegetation has not yet reached equilibrium with the present prevailing climate and that it is still in an initial stage of succession. We present results of eight upland sites sampled in the vicinity of Alexandra Fiord Lowland, Ellesmere Island, Canada, to demonstrate the slow recolonization process that has been occurring within the last 100–150 years after the LIA termination. The widespread presence of the "lichen-kill" zones throughout the Canadian polar regions reflects the extent and destructive nature of even minor climatic cooling on vulnerable polar ecosystems.     

Revision der geologischen Zeittafel für Nordamerika

Ohne Zusammenfassung     

Differential sedimentation versus coring artifacts: a comparison of two widely used piston-coring methods

In order to compare two widely used piston-coring techniques, parallel cores were taken with both a Kullenberg and a Livingstone corer in the deepest part of Soppensee (25 m), a small eutrophic Swiss lake containing varved sediments. The cores were taken within a horizontal distance of 3 m and yield comparable stratigraphic records. Differences in millimetre-scale microstructure are attributed to primary sedimentation processes at the water/sediment interface. Sediment thin-sections, as well as sediment x-radiograph investigations, reveal no difference in microstructure that could unequivocally be attributed to one of the coring methods used. The differences in deposition are therefore thought to reflect the inherent variability of lacustrine sedimentation in Soppensee.Major differences in overall core recovery do occur, however, in organic-rich, highly porous sediments. These variations are primarily attributed to differential gas expansion. Actual sediment-accumulation rates can therefore only be correctly estimated if the sedimentary record can be constrained within a high-resolution temporal framework, e.g. by annual laminations.     

Observations of Jet Diameter, Density and Dynamics

Collimated jets are believed to be an essential ingredient of the star formation process, and we are now able for the first time to test observationally the theories for their formation and propagation. The major advances achieved in recent years are reviewed, regarding the observed morphology, kinematics and excitation properties of jets, from the parsec-scale `giant outflows' down to the `microjets' from T Tauri stars. High angular resolution images and spectra have provided valuable estimates of jet diameter, space velocity, temperature, ionization fraction, electron and total density, both along and across the flow. We can thus calculate key physical quantites, as the shock excitation parameters, or the mass and momentum fluxes in the flow. The results obtained appear to validate the popular magneto-centrifugal models for jet launching, although some important issues are still under debate, as to the cause of knotty structures, observed wind thermal properties, and the dynamical relationship between jets and molecular outflows. Among the most interesting recent findings, we mention the observed indications for jet rotation, with inferred toroidal velocities consistent with the prescribed angular momentum balance between infall and outflow.     

Effects of social and climatic factors on building activity in the Czech lands between 1450 and 1950: a dendrochronological analysis

The development of settlement and building activity is the result of socioeconomic, political and demographic changes in the past. However, accurate information on temporal variation in building activity is rather limited. Dendrochronological databases containing dated historical wooden constructions provide an important resource. We used 6514 tree-felling dates to reconstruct building activity in the Czech lands for the period 1450–1950. Comparing felling dates with historical events demonstrated that building activity was negatively associated with intense wars, particularly during the Thirty Years' War (1618–1648). After the Peace of Westphalia (1648), socioeconomic renewal and demographic growth were reflected in an upsurge of building activity, especially ecclesiastical buildings. While the construction of ecclesiastical and noble buildings culminated around the 1720s, rural buildings peaked in the 1780s and the 1820s. Although no direct effect of climate was demonstrated, adverse climatic conditions leading to harvest failures and subsequent famines (e.g. the ‘Hunger Years’ 1770–1772) significantly contributed to declines in building activity. In contrast, a higher number of felling dates were detected when strong and/or frequent windstorms occurred. This study provides a comprehensive understanding of building activity in Central Europe and advocates the use of dendrochronological databases for the investigation of human activities in history.