Tracks of immigrant political incorporation

Models of Immigrant Political Incorporation brings together a multidisciplinary group of scholars to consider pathways by which immigrants may be incorporated into the political processes of western democracies. It builds on a rich tradition of studying immigrant incorporation, but each chapter innovates by moving beyond singular accounts of particular groups and locations toward a general causal model with the scope and breadth to apply across groups, places, and time. Models of Immigrant Political Incorporation addresses three key analytic questions: what, if anything, are the distinctive features of immigrants or immigrant groups? How broadly should one define and study politics? What are the initial premises for analyzing pathways toward incorporation; does one learn more by starting from an assumption of racialization and exclusion or from an assumption of engagement and inclusion? While all models engage with all three key analytic questions, chapters vary in their relative focus on one or another, and in the answers they provide. Most include graphical illustrations of the model, as well as extended examples applying the model to one or more immigrant populations. At a time when research on immigrant political incorporation is rapidly accumulating - and when immigrants are increasingly significant political actors in many democratic polities — this volume makes a timely and valuable intervention by pushing researchers to articulate causal dynamics, provide clear definitions and measurable concepts, and develop testable hypotheses. Furthermore, the wide array of frameworks examining how immigrants become part of a polity or are shunted aside ensure that activists and analysts alike will find useful insights. By including historians, sociologists, and political scientists, by ranging across North America and Western Europe, by addressing successful and failed incorporative efforts, this handbook offers guides for anyone seeking to develop a dynamic, unified, and supple model of immigrant political incorporation.

Timing of Tertiary Extension in the Railroad Valley Pioche Transect, Nevada: Constraints from Ar-40/Ar-39 Ages of Volcanic Rocks

Time-space relations of extension and volcanism place critical constraints on models of Basin and Range extensional processes. This paper addresses such relations in a 130-km-wide transect in the eastern Great Basin, bounded on the east by the Ely Springs Range and on the west by the Grant and Quinn Canyon ranges. Stratigraphic and structural data, combined with 40Ar/39Ar isotopic ages of volcanic rocks, document a protracted but distinctly episodic extensional history. Field relations indicate four periods of faulting. Only one of these periods was synchronous with nearby volcanic activity, which implies that volcanism and faulting need not be associated closely in space and time. Based on published dates and the analyses reported here, the periods of extension were (1) prevolcanic (pre-32 Ma), (2) early synvolcanic (30 to 27 Ma), (3) immediately postvolcanic (about 16 to 14 Ma), and (4) Pliocene to Quaternary. The break between the second and third periods is distinct. The minimum gap between the first two periods is 2 Ma, but the separation may be much larger. Temporal separation of the last two periods is only suggested by the stratigraphic record and cannot be rigorously demonstrated with present data. The three younger periods of faulting apparently occurred across the entire transect. The oldest period is recognized only at the eastern end of the transect, but appears to correlate about 150 km northward along strike with extension in the Northern Snake Range-Kern Mountains area. Therefore the oldest period also is regional in extent, but affected a different area than that affected by younger periods. This relation suggests that distinct extensional structures and master detachment faults were active at different times. The correlation of deformation periods of a few million years duration across the Railroad Valley-Pioche transect suggests that the scale of active extensional domains in the Great Basin may be greater than 100 km across strike.

The evolution of scarab beetles tracks the sequential rise of angiosperms and mammals

Extant terrestrial biodiversity arguably is driven by the evolutionary success of angiosperm plants, but the evolutionary mechanisms and timescales of angiosperm-dependent radiations remain poorly understood. The Scarabaeoidea is a diverse lineage of predominantly plant- and dung-feeding beetles. Here, we present a phylogenetic analysis of Scarabaeoidea based on four DNA markers for a taxonomically comprehensive set of specimens and link it to recently described fossil evidence. The phylogeny strongly supports multiple origins of coprophagy, phytophagy and anthophagy. The ingroup-based fossil calibration of the tree widely confirmed a Jurassic origin of the Scarabaeoidea crown group. The crown groups of phytophagous lineages began to radiate first (Pleurostict scarabs: 108 Ma; Glaphyridae between 101 Ma), followed by the later diversification of coprophagous lineages (crown-group age Scarabaeinae: 76 Ma; Aphodiinae: 50 Ma). Pollen feeding arose even later, at maximally 62 Ma in the oldest anthophagous lineage. The clear time lag between the origins of herbivores and coprophages suggests an evolutionary path driven by the angiosperms that first favoured the herbivore fauna (mammals and insects) followed by the secondary radiation of the dung feeders. This finding makes it less likely that extant dung beetle lineages initially fed on dinosaur excrements, as often hypothesized.