Compatible actions and non-abelian tensor products

For a pair of groups $G, H$ we study pairs of actions $G$ on $H$ and $H$ on $G$ such that these pairs are compatible and non-abelian tensor products $G \otimes H$ are defined.Comment: 9 page

Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes

BACKGROUND We sought to compare uterine cervical electrical impedance spectroscopy measurements employing two probes of different sizes, and to employ a finite element model to predict and compare the fraction of electrical current derived from subepithelial stromal tissue. METHODS Cervical impedance was measured in 12 subjects during early pregnancy using 2 different sizes of the probes on each subject. RESULTS Mean cervical resistivity was significantly higher (5.4 vs. 2.8 Ωm; p < 0.001) with the smaller probe in the frequency rage of 4–819 kHz. There was no difference in the short-term intra-observer variability between the two probes. The cervical impedance measurements derived in vivo followed the pattern predicted by the finite element model. CONCLUSION Inter-electrode distance on the probes for measuring cervical impedance influences the tissue resistivity values obtained. Determining the appropriate probe size is necessary when conducting clinical studies of resistivity of the cervix and other human tissues

The influence of native macroalgal canopies on the distribution and abundance of the non-native kelp Undaria pinnatifida in natural reef habitats

The Asian kelp Undaria pinnatifida (‘Wakame’) is one of the most widespread invasive non-native species in coastal marine habitats and is fast approaching cosmopolitan status, yet its interactions with native species are poorly understood. Within the Plymouth Sound (UK) Special Area of Conservation (SAC), Undaria has become a conspicuous and important component of assemblages in shallow rocky reef habitats, where it co-exists with native canopy-forming brown macroalgae. We examined the hypothesis that rocky reef habitats supporting dense macroalgal canopies will have more biotic resistance to the invasion of Undaria compared with reef habitats supporting disturbed or sparse native canopies. Field surveys were completed at two spatial scales and sampling resolutions, and a short-term field-based canopy removal experiment was conducted to examine the influence of native macroalgal assemblages on the abundance, cover, biomass and morphology of Undaria. Field surveys indicated that Undaria was negatively related to the cover of macroalgal ‘competitors’, particularly Laminaria spp. However, multiple, large Undaria sporophytes were observed within dense native canopies, suggesting that disturbance to, or the absence of, canopies is not a prerequisite for Undaria colonisation. The short-term canopy removal experiment indicated that Undaria functions primarily as a pioneer species in this system. Where native canopies were left intact, Undaria sporophytes were far less abundant and were generally smaller with lower biomass compared with those in disturbed patches. The spread of Undaria into natural habitats is inhibited by the presence of native competitors, particularly large perennial species such as Laminaria spp., although the persistence of intact dense canopies does not completely prevent assimilation of Undaria into native assemblages

Stages of development and injury: an epidemiological survey of young children presenting to an emergency department

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; The aim of our study was to use a local (Glasgow, west of Scotland) version of a Canadian injury surveillance programme (CHIRPP) to investigate the relationship between the developmental stage of young (pre-school) children, using age as a proxy, and the occurrence (incidence, nature, mechanism and location) of injuries presenting to a Scottish hospital emergency department, in an attempt to replicate the findings of a recent study in Kingston, Canada.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; We used the Glasgow CHIRPP data to perform two types of analyses. First, we calculated injury rates for that part of the hospital catchment area for which reasonably accurate population denominators were available. Second, we examined detailed injury patterns, in terms of the circumstances, mechanisms, location and types of injury. We compared our findings with those of the Kingston researchers.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; A total of 17,793 injury records for children aged up to 7 years were identified over the period 1997–99. For 1997–2001, 6,188 were used to calculate rates in the west of the city only. Average annual age specific rates per 1000 children were highest in both males and females aged 12–35 months. Apart from the higher rates in Glasgow, the pattern of injuries, in terms of breakdown factors, mechanism, location, context, and nature of injury, were similar in Glasgow and Kingston.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusion:&lt;/b&gt; We replicated in Glasgow, UK, the findings of a Canadian study demonstrating a correlation between the pattern of childhood injuries and developmental stage. Future research should take account of the need to enhance statistical power and explore the interaction between age and potential confounding variables such as socio-economic deprivation. Our findings highlight the importance of designing injury prevention interventions that are appropriate for specific stages of development in children.&lt;/p&gt

Dutch parallel corpus: a balanced parallel corpus for Dutch-English and Dutch-French

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Scavenger 0.1: A Theorem Prover Based on Conflict Resolution

This paper introduces Scavenger, the first theorem prover for pure first-order logic without equality based on the new conflict resolution calculus. Conflict resolution has a restricted resolution inference rule that resembles (a first-order generalization of) unit propagation as well as a rule for assuming decision literals and a rule for deriving new clauses by (a first-order generalization of) conflict-driven clause learning.Comment: Published at CADE 201

Structural subnetwork evolution across the life-span: rich-club, feeder, seeder

The impact of developmental and aging processes on brain connectivity and the connectome has been widely studied. Network theoretical measures and certain topological principles are computed from the entire brain, however there is a need to separate and understand the underlying subnetworks which contribute towards these observed holistic connectomic alterations. One organizational principle is the rich-club - a core subnetwork of brain regions that are strongly connected, forming a high-cost, high-capacity backbone that is critical for effective communication in the network. Investigations primarily focus on its alterations with disease and age. Here, we present a systematic analysis of not only the rich-club, but also other subnetworks derived from this backbone - namely feeder and seeder subnetworks. Our analysis is applied to structural connectomes in a normal cohort from a large, publicly available lifespan study. We demonstrate changes in rich-club membership with age alongside a shift in importance from 'peripheral' seeder to feeder subnetworks. Our results show a refinement within the rich-club structure (increase in transitivity and betweenness centrality), as well as increased efficiency in the feeder subnetwork and decreased measures of network integration and segregation in the seeder subnetwork. These results demonstrate the different developmental patterns when analyzing the connectome stratified according to its rich-club and the potential of utilizing this subnetwork analysis to reveal the evolution of brain architectural alterations across the life-span

Apneusis responding to buspirone in multiple sclerosis

Apneusis is a disturbance of respiratory rhythm characterized by severely prolonged inspiratory effort, and is caused by bilateral lesions in the dorsal pons. In humans it is most commonly caused by pontine infarction and has rarely been reported in multiple sclerosis (MS). Here we report on a patient with MS who developed episodic apneusis which responded to treatment with buspirone, a serotonin type 1A receptor agonist

Phenotypic Characterization, Osteoblastic Differentiation, and Bone Regeneration Capacity of Human Embryonic Stem Cell-Derived Mesenchymal Stem Cells

To enhance the understanding of differentiation patterns and bone formation capacity of hESCs, we determined (1) the temporal pattern of osteoblastic differentiation of human embryonic stem cell derived mesenchymal stem cells (hESC-MSCs), (2) the influence of a three-dimensional matrix on the osteogenic differentiation of hESC-MSCs in long-term culture, and (3) the bone-forming capacity of osteoblast-like cells derived from hESC-MSCs in calvarial defects. Incubation of hESC-MSCs in osteogenic medium induced osteoblastic differentiation of hESC-MSCs into mature osteoblasts in a similar chronological pattern to human bone marrow stromal cells and primary osteoblasts. Osteogenic differentiation was enhanced by culturing the cells on three-dimensional collagen scaffolds. Fluorescent-activated cell sorting of alkaline phosphatase expressing cells was used to obtain an enriched osteogenic cell population for in vivo transplantation. The identification of green fluorescence protein and expression of human-specific nuclear antigen in osteocytes in newly formed bone verified the role of transplanted human cells in the bone regeneration process. The current cell culture model and osteogenic cell enrichment method could provide large numbers of osteoprogenitor cells for analysis of differentiation patterns and cell transplantation to regenerate skeletal defects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78154/1/scd.2008.0310.pd

The CMB and the measure of the multiverse

In the context of eternal inflation, cosmological predictions depend on the choice of measure to regulate the diverging spacetime volume. The spectrum of inflationary perturbations is no exception, as we demonstrate by comparing the predictions of the fat geodesic and causal patch measures. To highlight the effect of the measure---as opposed to any effects related to a possible landscape of vacua---we take the cosmological model, including the model of inflation, to be fixed. We also condition on the average CMB temperature accompanying the measurement. Both measures predict a 1-point expectation value for the gauge-invariant Newtonian potential, which takes the form of a (scale-dependent) monopole, in addition to a related contribution to the 3-point correlation function, with the detailed form of these quantities differing between the measures. However, for both measures both effects are well within cosmic variance. Our results make clear the theoretical relevance of the measure, and at the same time validate the standard inflationary predictions in the context of eternal inflation.Comment: 28 pages; v2: reference added, some clarification