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UNLABELLED Movement during or between PET examinations is a common and serious problem. Consequently, there is a great need for rapid, accurate and robust methods to realign image sets. METHODS Derivative information from the image sets was used to extract areas containing edge information. Image similarity between a reference dataset and a misaligned(More)
Infants under six months are able to discriminate native and non-native consonant contrasts equally well, but as they learn the phonological systems of their native language, this ability declines. Current explanations of this phenomenon agree that the decline in discrimination ability is linked to the formation of native-language phonemic categories. The(More)
Performance is a central requirement to the wide-spread adoption of virtualization. To deliver on the promise of simplifying IT via virtualization, the virtualization platform must provide excellent performance with minimal effort. Virtualization performance encompasses several different dimensions. An application running in a virtual machine must perform(More)
Caenorhabditis elegans is an androdioecious nematode with both hermaphrodites and males. Although males can potentially play an important role in avoiding inbreeding and facilitating adaptation, their existence is evolutionarily problematic because they do not directly generate offspring in the way that hermaphrodites do. This review explores how genetic,(More)
The preferred body temperature of ectotherms is typically inferred from the observed distribution of body temperatures in a laboratory thermal gradient. For very small organisms, however, that observed distribution might misrepresent true thermal preferences. Tiny ectotherms have limited thermal inertia, and so their body temperature and speed of movement(More)
Sexual reproduction shuffles genetic variation, potentially enhancing the evolutionary response to environmental change. Many asexual organisms respond to stress by generating facultative sexual reproduction, presumably as a means of escaping the trap of low genetic diversity. Self-fertilizing organisms are subject to similar genetic limitations: the(More)
Many mutations that dramatically extend life span in model organisms come with substantial fitness costs. Although these genetic manipulations provide valuable insight into molecular modulators of life span, it is currently unclear whether life-span extension is unavoidably linked to fitness costs. To examine this relationship, we evolved a genetically(More)
In adult male rats, spinal nucleus of the bulbocavernosus (SNB) motoneurons shrink after castration and are restored in size after androgen treatment. Sixty-day-old Sprague Dawley males were castrated and implanted with SILASTIC capsules containing testosterone (T) or nothing, and osmotic minipumps continuously infusing MK-801, a noncompetitive NMDA(More)
The mdx (muscular dystrophy X-linked) mouse is a model for human Duchenne muscular dystrophy (DMD) and is characterized by the absence of the cytoskeletal protein dystrophin. Using a cerebellar slice preparation, we show that postsynaptically mediated long-term depression (LTD) is significantly reduced in mdx Purkinje cells, while presynaptically mediated(More)
Opioid dependence is a problem of national concern, especially with dramatically increased rates of abuse and dependence of prescription opioids. The current article provides an up-to-date review of the literature on opioid dependence treatment, with a focus on conclusions drawn by experts in the field (e.g., Cochrane reviews and meta-analyses) and(More)