95,385 research outputs found
Macrophage defences against respiratory tract infections
No full textPulmonary macrophages with a key role in defence against respiratory infection are a heterogeneous family of cells with phagocytic, antigen processing and immunomodulatory functions. Macrophages are important in both innate and acquired immunity in the respiratory tract, and have a role in lung defence against viruses, bacteria, mycobacteria and fungi. Interactions of pathogens with lung macrophages is strongly influenced by soluble immune components including complement, collectins and immunoglobulins. Macrophage function can be modulated by cytokines, environmental exposures, recent and chronic infection including HIV infection, drug therapy and gene transfer.</p
ChIP-seq Analysis in R (CSAR): An R package for the statistical detection of protein-bound genomic regions
No full textAbstract Background In vivo detection of protein-bound genomic regions can be achieved by combining chromatin-immunoprecipitation with next-generation sequencing technology (ChIP-seq). The large amount of sequence data produced by this method needs to be analyzed in a statistically proper and computationally efficient manner. The generation of high copy numbers of DNA fragments as an artifact of the PCR step in ChIP-seq is an important source of bias of this methodology. Results We present here an R package for the statistical analysis of ChIP-seq experiments. Taking the average size of DNA fragments subjected to sequencing into account, the software calculates single-nucleotide read-enrichment values. After normalization, sample and control are compared using a test based on the ratio test or the Poisson distribution. Test statistic thresholds to control the false discovery rate are obtained through random permutations. Computational efficiency is achieved by implementing the most time-consuming functions in C++ and integrating these in the R package. An analysis of simulated and experimental ChIP-seq data is presented to demonstrate the robustness of our method against PCR-artefacts and its adequate control of the error rate. Conclusions The software ChIP-seq Analysis in R (CSAR) enables fast and accurate detection of protein-bound genomic regions through the analysis of ChIP-seq experiments. Compared to existing methods, we found that our package shows greater robustness against PCR-artefacts and better control of the error rate.</p
Reading in the mobile era
No full textMobile technology can advance literacy and learning in underserved communities around the world.
Summary
Millions of people do not read for one reason: they do not have access to text. But today mobile phones and cellular networks are transforming a scarce resource into an abundant one.
Drawing on the analysis of over 4,000 surveys collected in seven developing countries and corresponding qualitative interviews, this report paints the most detailed picture to date of who reads books and stories on mobile devices and why.
The findings illuminate, for the first time, the habits, beliefs and profiles of mobile readers. This information points to strategies to expand mobile reading and, by extension, the educational, social and economic benefits associated with increased reading.
Mobile technology can advance literacy and learning in underserved communities around the world. This report shows how
Designing role-based view for object-relational databases
No full textIn a federated database system, a view mechanism is crucial since it is used to define exportable subsets of data ; to perform a virtual restructuring d ataset; and to construct the integrated schema. The view service in federated databa se systems must be capable of retaining as much semantic information as possible. The object-oriented ( 0 - 0 ) model was considered the suitable canonical data model since it meets the original criteria for canonical model selection. However, with the emergence of stronger object-relational (0 -R ) model, the re is a clear argument for using an 0 - R canonical model in the federation. Hence, research should now focus on th e development of semantically powerful view mechanism for th e newer model. Meanwhile, the availability of real 0 -R technologies offers researchers the opportunity to develop different forms of view mechanisms.
The concept of roles has been widely studied in 0 - 0 modelling and development. The role model represents some characteristics that the traditional 0-0 model lacked, such as object migration, multiple occurrences and context-dependent access. While many forms of 0-0 views were designed for the 0-0 canonical model, one option was to extend the 0-0 model to incorporate a role model. In a role model, the real entity is modelled in the form of a role rather than an object. An object represents the permanent properties of an entity is a root object; and an object represents the temporary properties of an entity is a role object.
The contribution of this research is to design a view system that employees the concept of roles for the 0 -R canonical model in a federated database system. In this thesis, an examination of the current 0 -R metamodel is provided first in order to provide an environment for recognising the roleview metadata and measuring the view performance; then a Roleview Definition Language (RDL) is introduced, along with the semantics for defining virtual classes and generating virtua l extents; finally, a working prototype is provided to prove th e role-based view system is implementable and the syntax is semantically correct
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Small RNA sequences from <i>91-C</i> and <i>91-R</i> triplicate libraries read data.
No full textSmall RNA sequences from 91-C and 91-R triplicate libraries read data.</p
Correlation of group C meningococcal conjugate vaccine response with B- and T-lymphocyte activity.
No full textDespite the success of conjugate vaccination against meningococcal group C (MenC) disease, post-vaccination, some individuals still exhibit rapid waning of initially protective bactericidal antibody levels. The mechanism of this relative loss of humoral protection remains undetermined. In this report we have investigated the relationship between T- and B-cell activation and co-stimulation and the loss of protective antibody titers. We have found that healthy volunteers who lose protective MenC antibody levels one year after receipt of glycoconjugate vaccine exhibit no detectable cellular defect in polyclonal B- or T-cell activation, proliferation or the B-memory pool. This suggests that the processes underlying the more rapid loss of antibody levels are independent of defects in either initial T- or B-cell activation
Mapping and QTL analysis of the barley population Sloop x Halcyon
No full textA genetic linkage map of Hordeum vulgare L. 1280 cM in length, composed of 257 AFLP, RFLP, SNP, and microsatellite markers, has been constructed. The map was based on a doubled haploid population made from the cross Sloop (spring type) × Halcyon (winter type). The genetic map was used to identify qualitative major genes and quantitative trait loci (QTLs) affecting traits related to growth and flowering, grain colour, and disease resistance. Nine QTLs associated with grain colour (brightness, redness, yellowness, blue aleurone colour), plant height, 'intrinsic lateness', awn emergence, response to photoperiod, and spring or winter habit were located on 1H, 2H, 3H, 4H, and 5H. Eight QTLs associated with resistance to scald, net form of net blotch, leaf rust and powdery mildew were identified on chromosomes 1H, 2H, 3H, 4H, 5H, and 7H. The estimated magnitude of the QTL effects ranged from 9 to 85% of the total phenotypic variance. Resistances to leaf scald, net blotch, and leaf rust, and photoperiod and grain colour, were each controlled by at least one major gene.B. J. Read, H. Raman, G. McMichael, K. J. Chalmers, G. A. Ablett, G. J. Platz, R. Raman, R. K. Genger, W. J. R. Boyd, C. D. Li, C. R. Grime, R. F. Park, H. Wallwork, R. Prangnell and R. C. M. Lanc
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