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Search Results: 1 - 10 of 307014 matches for " J George Gibbings "
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Transgenerational, Dynamic Methylation of Stomata Genes in Response to Low Relative Humidity
Penny J. Tricker,Carlos M. Rodríguez López,George Gibbings,Paul Hadley,Mike J. Wilkinson
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14046674
Abstract: Transgenerational inheritance of abiotic stress-induced epigenetic modifications in plants has potential adaptive significance and might condition the offspring to improve the response to the same stress, but this is at least partly dependent on the potency, penetrance and persistence of the transmitted epigenetic marks. We examined transgenerational inheritance of low Relative Humidity-induced DNA methylation for two gene loci in the stomatal developmental pathway in Arabidopsis thaliana and the abundance of associated short-interfering RNAs (siRNAs). Heritability of low humidity-induced methylation was more predictable and penetrative at one locus ( SPEECHLESS, entropy ≤ 0.02; χ 2 < 0.001) than the other ( FAMA, entropy ≤ 0.17; χ 2 ns). Methylation at SPEECHLESS correlated positively with the continued presence of local siRNAs ( r 2 = 0.87; p = 0.013) which, however, could be disrupted globally in the progeny under repeated stress. Transgenerational methylation and a parental low humidity-induced stomatal phenotype were heritable, but this was reversed in the progeny under repeated treatment in a previously unsuspected manner.
Analysis of wheat SAGE tags reveals evidence for widespread antisense transcription
Rebecca L Poole, Gary LA Barker, Kay Werner, Gaia F Biggi, Jane Coghill, J George Gibbings, Simon Berry, Jim M Dunwell, Keith J Edwards
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-475
Abstract: Examination of 71,930 Long SAGE tags generated from six libraries derived from two wheat genotypes grown under two different conditions suggested that SAGE is a reliable and reproducible technique for use in studying the hexaploid wheat transcriptome. However, our results also showed that in poorly annotated and/or poorly sequenced genomes, such as hexaploid wheat, considerably more information can be extracted from SAGE data by carrying out a systematic analysis of both perfect and "fuzzy" (partially matched) tags. This detailed analysis of the SAGE data shows first that while there is evidence of alternative polyadenylation this appears to occur exclusively within the 3' untranslated regions. Secondly, we found no strong evidence for widespread alternative splicing in the developing wheat grain transcriptome. However, analysis of our SAGE data shows that antisense transcripts are probably widespread within the transcriptome and appear to be derived from numerous locations within the genome. Examination of antisense transcripts showing sequence similarity to the Puroindoline a and Puroindoline b genes suggests that such antisense transcripts might have a role in the regulation of gene expression.Our results indicate that the detailed analysis of transcriptome data, such as SAGE tags, is essential to understand fully the factors that regulate gene expression and that such analysis of the wheat grain transcriptome reveals that antisense transcripts maybe widespread and hence probably play a significant role in the regulation of gene expression during grain development.With cereals constituting more than 60% of the world's dietary intake, the bread wheat Triticum aestivum is one of the most important crops in world agriculture [1,2]. Despite the high yields achieved in Europe there is still a real need to generate improved cultivars, as yield and flour quality can be dramatically affected by the environment. This need has become even greater in recent years with tight
Rese a de "Guadalupanismo en Guatemala: Culto mariano y subalternidad étnica" (Arturo Taracena Arriola). Mérida, Universidad Nacional Autónoma de México, 2008, 230 páginas.
Julie Gibbings
HIb Revista de Historia Iberoamericana , 2010,
CD8α is expressed by human monocytes and enhances FcγR-dependent responses
Derrick J Gibbings, Marcelo Marcet-Palacios, Yokananth Sekar, Marcus CY Ng, A Dean Befus
BMC Immunology , 2007, DOI: 10.1186/1471-2172-8-12
Abstract: We detected CD8α, but not CD8β on human monocytes and the monocytic cell line THP-1 by flow cytometry. Reactivity of anti-CD8α mAb with monocytes is at least partly independent of FcR as anti-CD8α mAb detect CD8α by western blot and inhibit binding of MHC class I tetramers. CD8α mRNA is also found in monocytes and THP-1 suggesting CD8α is synthesized by monocytes and not acquired from other CD8α+ cell types. Interestingly, CD8α from monocytes and blood T cells presented distinguishable patterns by 2-D electrophoresis. Anti-CD8α mAb alone did not activate monocyte TNF release. In comparison, TNF release by human monocytes stimulated in a FcR-dependent manner with immune-complexes was enhanced by inclusion of anti-CD8α mAb in immune-complexes.Human monocytes express CD8α. Co-engagement of CD8α and FcR enhances monocyte TNF release, suggesting FcR may be a novel partner receptor for CD8α on innate immune cells.CD8α is a surface glycoprotein typically found on a subpopulation of CTL [1]. CD8α enhances responses instigated through the TCR by binding MHC class I and signaling through the src kinase lck and the adaptor protein Linker for Activation of T cells (LAT) [2]. The classical co-receptor model of CD8 suggests CD8 enhances CTL activation by binding the same MHC class I-peptide as TCR [3]. Other evidence suggests CD8 is recruited to the site of T cell activation [4,5]. and can enhance T cell responses even when it does not bind at detectable levels to the same MHC class I-peptide as TCR (e.g. CD8 enhances activation of T cells with an MHC class II specific TCR [6,7]).CD8 on T cells co-activates responses initiated by TCR, but no such co-activating role has been described for CD8 on other CD8+ cells like dendritic cells [8], NK cells [9,10]., mast cells [11] or macrophages (Mφ) [12]. Interestingly, the Fcγ chain, a component of several FcR [13], NK receptors [14], and ILT1 [15] can substitute for CD3ζ in TCR expression [16,17].; signaling [18] and T cell activation [1
Education and Socialization in Ghana  [PDF]
George J. Sefa Dei
Creative Education (CE) , 2011, DOI: 10.4236/ce.2011.22014
Abstract: Africa has always been an important source of rich information for knowledge production. There has always been a curiosity about Africa that has served different imaginations and interests. But how do we learn and teach about Africa in ways that are informed by an appreciation of African peoples’ rich cultural knowledges, com- plexity and historic resistance of local peoples to carve out their own futures and dreams? I would maintain that knowing about education and socialization offer some important directions in this search for knowledge. Tradi- tional African education has utilized a variety of instructional and pedagogic methods as well as guides and resources to educate youth. Education in African communities has happened in multiple sites, formal and non-formal. Just as West African education can benefit from a study of educational delivery in other contexts, I would argue that a study of important aspects of West African formal and non formal education and socializa- tion of young learners may offer significant lessons for educating youth in other societies. There is intellectual relevance in asking such questions as: What and how do students in West African learn? What activities, stories do students experience in their education that can be incorporated into the curriculum to enrich educating stu- dents from diverse backgrounds in other contexts? What is the nature of the environment in which students learn in West Africa?
Adaptive Fractional Polynomial Modeling  [PDF]
George J. Knafl
Open Journal of Statistics (OJS) , 2018, DOI: 10.4236/ojs.2018.81011
Abstract: Regression analyses reported in the applied research literature commonly assume that relationships are linear in predictors without assessing this assumption. Fractional polynomials provide a general approach for addressing nonlinearity through power transforms of predictors using real valued powers. An adaptive approach for generating fractional polynomial models is presented based on heuristic search through alternative power transforms of predictors guided by k-fold likelihood cross-validation (LCV) scores and controlled by tolerance parameters indicating how much a reduction in the LCV score can be tolerated at given stages of the search. The search optionally can generate geometric combinations, that is, products of power transforms of multiple predictors, thereby supporting nonlinear moderation analyses. Positive valued continuous outcomes can be power transformed as well as predictors. These methods are demonstrated using data from a study of family management for mothers of children with chronic physical conditions. The example analyses demonstrate that power transformation of a predictor may be required to identify that a relationship holds between that predictor and an outcome (dependent or response) variable. Consideration of geometric combinations can identify moderation effects not identifiable using linear relationships or power transforms of interactions. Power transformation of positive valued continuous outcomes along with their primary predictors can resolve model assumption problems.
A Reassessment of Birth Defects for Children of Participants of the Air Force Health Study  [PDF]
George J. Knafl
Open Journal of Epidemiology (OJEpi) , 2018, DOI: 10.4236/ojepi.2018.84015
Abstract: The Air Force Health Study (AFHS), also called the Ranch Hand Study, investigated the impact of exposure to dioxin the toxic contaminant in Agent Orange on health, survival, and reproductive outcomes of male Air Force Vietnam War veterans. It was concluded that available reproductive outcome data did not provide support for an adverse association with paternal dioxin exposure. A more extensive set of AFHS data was used to reassess this conclusion, restricting to the case of birth defects in children fathered after the start of the first Vietnam War tour. Analyses started by repeating published analyses, followed by assessing decisions made in those analyses, for example, of excluding participants with dioxin levels below the detectable limit, using a threshold of 10 parts per trillion for a high dioxin level, and not adjusting for multiple conceptions/children of the same participant. Using data for all participants with measured dioxin levels, both veterans who served in Operation Ranch Hand and other non-Ranch Hand veterans, and after accounting for correlation within children of the same participant, the occurrence for children fathered after the start of the first tour of a major defect, a non-major defect, and multiple defects depended significantly on participants having a high dioxin level. These conclusions were not changed by consideration of covariates. In contrast to prior published analyses, the more extensive AFHS data provided support for an adverse effect of paternal dioxin exposure on birth defects. However, the study had many limitations that could have affected the conclusions.
Dynamic Modeling of the Harvesting Function: The Conflicting Case  [PDF]
George Emm Halkos, George J. Papageorgiou
Modern Economy (ME) , 2014, DOI: 10.4236/me.2014.57073

This paper is concerned with the classic topic of intertemporal resource economics: the optimal harvesting of renewable natural resources over time by one and several resource extractors with conflicting interests. The traditional management model, dating back to Plourde [1], is overlooked both in the simple case for which the resource stock is treated as a state variable and in the improved case for which the harvesting equipment is treated as a stock variable. As a result in the extended case, the equilibrium richer than the saddle point, with bifurcations and limit cycles, is possible. While the results of the enriched management case are consistent with the concept of the pulse fishing, as this concept is introduced by Clark [2]-[4], in the conflicting case the conditions, under which the richer limit cycle equilibrium occurs, are not enough investigated. Therefore, we discuss conflicts as a game with two types of players involved: the traditional fishermen armed with the basic equipment and the heavy equipment users. Both players have a common depletion function, considered as harvesting, which is dependent together on personal effort and on intensity of equipment’s usage.

Colonial Figures: Memories of Street Traders in the Colonial and Early Post-colonial Periods
Sheri Lynn Gibbings,Fridus Steijlen
Public History Review , 2012,
Abstract: This article explores post-colonial memories about street traders among individuals who lived in the former colony of the Dutch East Indies. It argues that these narratives romanticize the relationship between Europeans and indigenous peoples. Street vendors are also used to differentiate between periods within colonial and post-colonial history. The nostalgic representation of interracial contact between Europeans and traders is contrasted with representations of other figures such as the Japanese and the nationalist. A recurring feature of these representations is the ability of Europeans to speak with street traders and imagine what they wanted and needed. The traders are remembered as a social type that transgressed politics and represented the neutrality of the economic sphere as a place for shared communication. The article concludes that the figure of the street vendor contributes to the nostalgic reinvention of the colony but is also used in narratives to differentiate between and mark changes across the colonial and post-colonial periods.
Evidence-Based Robust Design of Deflection Actions for Near Earth Objects
Federico Zuiani,Massimiliano Vasile,Alison Gibbings
Mathematics , 2012, DOI: 10.1007/s10569-012-9423-1
Abstract: This paper presents a novel approach to the robust design of deflection actions for Near Earth Objects (NEO). In particular, the case of deflection by means of Solar-pumped Laser ablation is studied here in detail. The basic idea behind Laser ablation is that of inducing a sublimation of the NEO surface, which produces a low thrust thereby slowly deviating the asteroid from its initial Earth threatening trajectory. This work investigates the integrated design of the Space-based Laser system and the deflection action generated by laser ablation under uncertainty. The integrated design is formulated as a multi-objective optimisation problem in which the deviation is maximised and the total system mass is minimised. Both the model for the estimation of the thrust produced by surface laser ablation and the spacecraft system model are assumed to be affected by epistemic uncertainties (partial or complete lack of knowledge). Evidence Theory is used to quantify these uncertainties and introduce them in the optimisation process. The propagation of the trajectory of the NEO under the laser-ablation action is performed with a novel approach based on an approximated analytical solution of Gauss' Variational Equations. An example of design of the deflection of asteroid Apophis with a swarm of spacecraft is presented.
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