Plant Diversity Changes during the Postglacial in East Asia: Insights from Forest Refugia on Halla Volcano, Jeju Island

Understanding how past climate changes affected biodiversity is a key issue in contemporary ecology and conservation biology. These diversity changes are, however, difficult to reconstruct from paleoecological sources alone, because macrofossil and pollen records do not provide complete information about species assemblages. Ecologists therefore use information from modern analogues of past communities in order to get a better understanding of past diversity changes. Here we compare plant diversity, species traits and environment between late-glacial Abies, early-Holocene Quercus, and mid-Holocene warm-temperate Carpinus forest refugia on Jeju Island, Korea in order to provide insights into postglacial changes associated with their replacement. Based on detailed study of relict communities, we propose that the late-glacial open-canopy conifer forests in southern part of Korean Peninsula were rich in vascular plants, in particular of heliophilous herbs, whose dramatic decline was caused by the early Holocene invasion of dwarf bamboo into the understory of Quercus forests, followed by mid-Holocene expansion of strongly shading trees such as maple and hornbeam. This diversity loss was partly compensated in the Carpinus forests by an increase in shade-tolerant evergreen trees, shrubs and lianas. However, the pool of these species is much smaller than that of light-demanding herbs, and hence the total species richness is lower, both locally and in the whole area of the Carpinus and Quercus forests. The strongly shading tree species dominating in the hornbeam forests have higher leaf tissue N and P concentrations and smaller leaf dry matter content, which enhances litter decomposition and nutrient cycling and in turn favored the selection of highly competitive species in the shrub layer. This further reduced available light and caused almost complete disappearance of understory herbs, including dwarf bamboo

The Politics of Federalism in Argentina: Implications for Governance and Accountability

This paper contributes to an agenda that views the effects of policies and institutional reforms as dependent on the structure of political incentives for national and subnational political actors. The paper studies political incentive structures at the subnational level and the mechanisms whereby they affect national-level politics and policymaking at the national level in Argentina, a highly decentralized middle-income democracy, Argentina. The Argentine political system makes subnational political power structures very influential in national politics. Moreover, most Argentine provinces are local bastions of power dominated by entrenched elites, characterized by scarce political competition, weak division of powers, and clientelistic political linkages. Political dominance in the provinces and political importance at the national level reinforce each other, dragging the Argentine political and policymaking system towards the practices and features of its most politically backward regions

Inward-Looking Policies, Institutions, Autocrats, and Economic Growth in Latin America: An Empirical Exploration

This paper explores the institutional determinants of economic growth in Latin America by taking advantage of recent empirical research that employs subjective and objective measures to test for a possible Northian explanation that links institutional quality and economic growth. I provide a framework that helps better understand the policymakers` choices and persistence regarding inward-looking policies that were pursued between the 1930s and the 1980s by arguing that in the Latin American case Olson`s (1982) idea of encompassing interest should be expanded to cover not only the economic stakes of power holders, but also, their political stakes, somewhat along the lines of work by Robinson (1997)

Prediction of Zn₂(V, Nb, Ta)N₃ Monolayers for Optoelectronic Applications

A new family of ternary nitride materials, Zn2(V, Nb, Ta)N3 monolayers, is predicted. A fabrication mechanism of the Zn2(V, Nb, Ta)N3 monolayers is proposed based on the chemical vapor deposition approach used for their bulk counterparts. The calculations show that these monolayers are thermodynamically and environmentally stable and that the Zn2VN3 monolayer is the most stable and the easiest to synthesize. The Zn2VN3 monolayer also has the highest strength and elasticity. The Zn2(V, Nb, Ta)N3 monolayers are semiconductors with nearly equal direct and indirect band gaps. Considering optoelectronic properties, the predicted monolayers are transparent to the visible light and provide shielding in the ultraviolet region. Thus, the predicted Zn2(V, Nb, Ta)N3 monolayers are promising for applications in LED devices and as blocking layers in tandem solar cells

Structural Study of Salicylic Acid Salts of a Series of Azacycles and Azacrown Ethers

Interaction of salicylic acid (saH) with the azacycles piperidine (pipe) and meso-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (teta) and with the aza-crown ethers aza-12-crown-4 (A12C4), benzoaza-15-crown-5 (BA15C5), aza-18-crown-6 (A18C6), and diaza-18-crown-6 (DA18C6) afforded the proton-transfer complexes (organic salts) of compositions [pipeH][sa], [tetaH2][sa]2, [A12C4H][sa], [BA15C5H][sa], [A18C6H][sa]·2H2O, and [DA18C6H2][sa]2·3H2O, whose structures were determined by a single crystal X-ray method. These products were also obtained by the same synthetic conditions starting from acetylsalicylic acid (aspirin) as a result of hydrolysis. The charge-assisted N−H···O hydrogen-bond provides the main driving force for direct binding of sa with cyclic azonia cations. The crystal packing is also supported by weak C−H···O hydrogen bonding and edge-to-face π···π intermolecular interactions