The neural correlates of picture naming facilitated by auditory repetition

Background: Overt repetition of auditorily presented words can facilitate picture naming performance in both unimpaired speakers and individuals with word retrieval difficulties, but the underlying neurocognitive mechanisms and longevity of such effects remain unclear. This study used functional magnetic resonance imaging to examine whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from an auditory repetition task in healthy older adults

Bringing the real world into the fMRI scanner: Repetition effects for pictures versus real objects

Our understanding of the neural underpinnings of perception is largely built upon studies employing 2-dimensional (2D) planar images. Here we used slow event-related functional imaging in humans to examine whether neural populations show a characteristic repetition-related change in haemodynamic response for real-world 3-dimensional (3D) objects, an effect commonly observed using 2D images. As expected, trials involving 2D pictures of objects produced robust repetition effects within classic object-selective cortical regions along the ventral and dorsal visual processing streams. Surprisingly, however, repetition effects were weak, if not absent on trials involving the 3D objects. These results suggest that the neural mechanisms involved in processing real objects may therefore be distinct from those that arise when we encounter a 2D representation of the same items. These preliminary results suggest the need for further research with ecologically valid stimuli in other imaging designs to broaden our understanding of the neural mechanisms underlying human vision

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Emissions Trading and the Polluter-Pays Principle : do Polluters Pay under Grandfathering?

Emissions trading is becoming increasingly popular in environmental law. Allowances to trade emissions can either be auctioned off or handed out free of charge by means of grandfathering. Although grandfathering is frequently used in emissions trading schemes, it is a popular view in the economic and legal literature that grandfathering is inconsistent with the polluter-pays principle. We come to a different, more nuanced view. The question of whether polluters pay under grandfathering depends on how the polluter-pays principle is interpreted. We present a taxonomy of interpretations. Based on an efficiency interpretation of the principle, consistency is demonstrated by emphasizing the economic impact of the opportunity costs of gratis allowances and the lump sum nature of the subsidy that is inherent to grandfathering. Inconsistency can only be claimed based on an equity interpretation of the polluter-pays principle. Allocating allowances free of charge means that polluting firms receive a capital gift making their shareholders richer, which may be perceived as unfair. We draw two conclusions. First, contrary to what some have claimed, grandfathering is compatible with an efficiency interpretation of the polluter-pays principle. Second, only auctioning is consistent with an extended form of this principle. Auctioning ensures not only that pollution costs are internalized (efficiency), but also that producers buy their allowances before they pass on those costs to consumers (equity)

Surviving in isolation: genetic variation, bottlenecks and reproductive strategies in the Canarian endemic Limonium macrophyllum (Plumbaginaceae)

Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their longterm survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (HT = 0.363), and substantial differentiation among populations (FST = 0.188;RST = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species’ limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence