7,729 research outputs found

    G2G_2 generating technique for minimal D=5 supergravity and black rings

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    A solution generating technique is developed for D=5 minimal supergravity with two commuting Killing vectors based on the G2G_2 U-duality arising in the reduction of the theory to three dimensions. The target space of the corresponding 3-dimensional sigma-model is the coset G2(2)/(SL(2,R)×SL(2,R))G_{2(2)}/(SL(2,R)\times SL(2,R)). Its isometries constitute the set of solution generating symmetries. These include two electric and two magnetic Harrison transformations with the corresponding two pairs of gauge transformations, three SL(2,R)SSL(2,R) S-duality transformations, and the three gravitational scale, gauge and Ehlers transformations (altogether 14). We construct a representation of the coset in terms of 7×77\times 7 matrices realizing the automorphisms of split octonions. Generating a new solution amounts to transforming the coset matrices by one-parametric subgroups of G2(2)G_{2(2)} and subsequently solving the dualization equations. Using this formalism we derive a new charged black ring solution with two independent parameters of rotation.Comment: 21 pages revtex-4, 1 figure, typo corrected in Eq. (103

    A general few-projection method for tomographic reconstruction of samples consisting of several distinct materials

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    We present a method for tomographic reconstruction of objects containing several distinct materials, which is capable of accurately reconstructing a sample from vastly fewer angular projections than required by conventional algorithms. The algorithm is more general than many previous discrete tomography methods, as: (i) a priori knowledge of the exact number of materials is not required; (ii) the linear attenuation coefficient of each constituent material may assume a small range of a priori unknown values. We present reconstructions from an experimental x-ray computed tomography scan of cortical bone acquired at the SPring-8 synchrotron

    The Journal of the Friends' Historical Society vol. 4 No. 1

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    1. Notes and Queries. 2. Our Bibliographers. 3. A New Book on George Fox. 4. American Letters of Edmund Peckover. 5. Meeting Records. 6. Friends at Newbury, Berkshire. 7. Presentations of Quakers in Episcopal Visitations, 1662-1679. 8. Friends on the Atlantic. 9. The Collection of Friends' Books in the Library of Haverford College, Pa. 10. The late Duke of Argyle's Estimate of Elizabeth Fry. 11. A so-called "Quaker Highwayman". 12. Matthew Raven, Stainesgate, Essex. 13. Brewers Yard Burial Ground. 14. Marriage Certificate - Hough-Barnes, 1676. 15. Paul Bevan's "One Little Book". 16. Land in New Jersey, 1685. 17. Minister and Merchant. 18. Friends in Current Literature. 19. Friends' Reference Library

    Lacunar-canalicular network in femoral cortical bone is reduced in aged women and is predominantly due to a loss of canalicular porosity

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    The lacunar-canalicular network (LCN) of bone contains osteocytes and their dendritic extensions, which allow for intercellular communication, and are believed to serve as the mechanosensors that coordinate the processes of bone modeling and remodeling. Imbalances in remodeling, for example, are linked to bone disease, including fragility associated with aging. We have reported that there is a reduction in scale for one component of the LCN, osteocyte lacunar volume, across the human lifespan in females. In the present study, we explore the hypothesis that canalicular porosity also declines with age. To visualize the LCN and to determine how its components are altered with aging, we examined samples from young (age: 20-23 y; n = 5) and aged (age: 70-86 y; n = 6) healthy women donors utilizing a fluorescent labelling technique in combination with confocal laser scanning microscopy. A large cross-sectional area of cortical bone spanning the endosteal to periosteal surfaces from the anterior proximal femoral shaft was examined in order to account for potential trans-cortical variation in the LCN. Overall, we found that LCN areal fraction was reduced by 40.6% in the samples from aged women. This reduction was due, in part, to a reduction in lacunar density (21.4% decline in lacunae number per given area of bone), but much more so due to a 44.6% decline in canalicular areal fraction. While the areal fraction of larger vascular canals was higher in endosteal vs. periosteal regions for both age groups, no regional differences were observed in the areal fractions of the LCN and its components for either age group. Our data indicate that the LCN is diminished in aged women, and is largely due to a decline in the canalicular areal fraction, and that, unlike vascular canal porosity, this diminished LCN is uniform across the cortex

    Investigating cooking activity patterns and perceptions of air quality interventions among women in urban Rwanda

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    Household air pollution (HAP) from biomass cooking with traditional stoves is a major cause of morbidity and mortality in low-and-middle-income countries (LMICs) worldwide. Air quality interventions such as improved cookstoves (ICS) may mitigate HAP-related impacts; however, poor understanding of contextual socio-cultural factors such as local cooking practices have limited their widespread adoption. Policymakers and stakeholders require an understanding of local cooking practices to inform effective HAP interventions which meet end-user needs. A semi-structured questionnaire was administered to 36 women residing in biomass-cooking fuel households in Kigali, Rwanda to identify cooking activity patterns, awareness of HAP-related health risks and ICS intervention preferences. Overall, 94% of respondents exclusively used charcoal cooking fuel and 53% cooked one meal each day (range = 1–3 meals). Women were significantly more likely to cook outdoors compared to indoors (64% vs. 36%; p < 0.05). Over half of respondents (53%) were unaware of HAP-related health risks and 64% had no prior awareness of ICS. Participants expressed preferences for stove mobility (89%) and facility for multiple pans (53%) within an ICS intervention. Our findings highlight the need for HAP interventions to be flexible to suit a range of cooking patterns and preferred features for end-users in this context

    Targeted transcriptomics reveals signatures of large-scale independent origins and concerted regulation of effector genes in Radopholus similis.

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    The burrowing nematode, Radopholus similis, is an economically important plant-parasitic nematode that inflicts damage and yield loss to a wide range of crops. This migratory endoparasite is widely distributed in warmer regions and causes extensive destruction to the root systems of important food crops (e.g., citrus, banana). Despite the economic importance of this nematode, little is known about the repertoire of effectors owned by this species. Here we combined spatially and temporally resolved next-generation sequencing datasets of R. similis to select a list of candidates for the identification of effector genes for this species. We confirmed spatial expression of transcripts of 30 new candidate effectors within the esophageal glands of R. similis by in situ hybridization, revealing a large number of pioneer genes specific to this nematode. We identify a gland promoter motif specifically associated with the subventral glands (named Rs-SUG box), a putative hallmark of spatial and concerted regulation of these effectors. Nematode transcriptome analyses confirmed the expression of these effectors during the interaction with the host, with a large number of pioneer genes being especially abundant. Our data revealed that R. similis holds a diverse and emergent repertoire of effectors, which has been shaped by various evolutionary events, including neofunctionalization, horizontal gene transfer, and possibly by de novo gene birth. In addition, we also report the first GH62 gene so far discovered for any metazoan and putatively acquired by lateral gene transfer from a bacterial donor. Considering the economic damage caused by R. similis, this information provides valuable data to elucidate the mode of parasitism of this nematode

    Inflating Lorentzian Wormholes

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    It has been speculated that Lorentzian wormholes of the Morris- Thorne type might be allowed by the laws of physics at submicroscopic, e.g. Planck, scales and that a sufficiently advanced civilization might be able to enlarge them to classical size. The purpose of this paper is to explore the possibility that inflation might provide a natural mechanism for the enlargement of such wormholes to macroscopic size. A new classical metric is presented for a Lorentzian wormhole which is imbedded in a flat deSitter space. It is shown that the throat and proper length of the wormhole inflate. The resulting properties and stress-energy tensor associated with this metric are discussed.Comment: 24 pg

    De novo Assembly and Analysis of the Chilean Pencil Catfish Trichomycterus areolatus Transcriptome

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    Trichomycterus areolatus is an endemic species of pencil catfish that inhabits the riffles and rapids of many freshwater ecosystems of Chile. Despite its unique adaptation to Chile’s high gradient watersheds and therefore potential application in the investigation of ecosystem integrity and environmental contamination, relatively little is known regarding the molecular biology of this environmental sentinel. Here, we detail the assembly of the Trichomycterus areolatus transcriptome, a molecular resource for the study of this organism and its molecular response to the environment. RNA-Seq reads were obtained by next-generation sequencing with an Illumina® platform and processed using PRINSEQ. The transcriptome assembly was performed using TRINITY assembler. Transcriptome validation was performed by functional characterization with KOG, KEGG, and GO analyses. Additionally, differential expression analysis highlights sex-specific expression patterns, and a list of endocrine and oxidative stress related transcripts are included
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