28 resultados para descent

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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The majority of reported learning methods for Takagi-Sugeno-Kang fuzzy neural models to date mainly focus on the improvement of their accuracy. However, one of the key design requirements in building an interpretable fuzzy model is that each obtained rule consequent must match well with the system local behaviour when all the rules are aggregated to produce the overall system output. This is one of the distinctive characteristics from black-box models such as neural networks. Therefore, how to find a desirable set of fuzzy partitions and, hence, to identify the corresponding consequent models which can be directly explained in terms of system behaviour presents a critical step in fuzzy neural modelling. In this paper, a new learning approach considering both nonlinear parameters in the rule premises and linear parameters in the rule consequents is proposed. Unlike the conventional two-stage optimization procedure widely practised in the field where the two sets of parameters are optimized separately, the consequent parameters are transformed into a dependent set on the premise parameters, thereby enabling the introduction of a new integrated gradient descent learning approach. A new Jacobian matrix is thus proposed and efficiently computed to achieve a more accurate approximation of the cost function by using the second-order Levenberg-Marquardt optimization method. Several other interpretability issues about the fuzzy neural model are also discussed and integrated into this new learning approach. Numerical examples are presented to illustrate the resultant structure of the fuzzy neural models and the effectiveness of the proposed new algorithm, and compared with the results from some well-known methods.

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Throughout the reign of Elizabeth I, a steady stream of tracts appeared in English print to vindicate the succession of the most prominent contenders, Mary and James Stuart of Scotland. This article offers a comprehensive account of the polemical battle between the supporters and opponents of the Stuarts, and further identifies various theories of English kingship, most notably the theory of corporate kingship, developed by the Stuart polemicists to defend the Scottish succession. James's accession to the English throne in March 1603 marked the protracted end of the debate over the succession. The article concludes by suggesting that, while powerfully renouncing the opposition to his succession, over the course of his attempt to unify his two kingdoms, James and his supporters ultimately departed from the polemic of corporate kingship, for a more assertive language of kingship by natural and divine law.

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This paper explores the school experiences of seven 11–14 year old disabled children, and focuses on their agency as they negotiated a complex, changing, and often challenging social world at school where “difference” was experienced in negative ways. The paper draws on ethnographic data from a wider three-year study that explores the influence of school experiences on both disabled and non-disabled children’s identity as they make the transition from primary to secondary school in regular New Zealand schools (although the focus of the present paper is only on the experiences of disabled children). The wider study considers how Maori (indigenous people of Aotearoa/New Zealand) and Pakeha (New Zealanders of NZ European descent) disabled children and their non- disabled matched peers (matched for age, gender and classroom) understand their personal identity, and how factors relating to transition (from primary to secondary school); culture; impairment (in the case of disabled children); social relationships; and school experience impact on children’s identities. Data on Maori children’s school experiences is currently being collected, and is not yet available for inclusion in this paper. On the basis of our observations in schools we will illustrate how disabled children felt and were made to feel different through an array of structural barriers such as separate provision for disabled students, and peer and teacher attitudes to diversity. However, we agree with Davis, Watson, Shakespeare and Corker’s (2003) interpretation that disabled children’s rights and participation at school are also under attack from a “deeper cultural division” (p. 205) in schools based on discourses of difference and normality. While disabled students in our study were trying to actively construct and shape their social and educational worlds, our data also show that teachers and peers have the capacity to either support or supplant these attempts to be part of the group of “all children”. We suggest that finding solutions that support disabled children’s full inclusion and participation at school requires a multi-faceted and systemic approach focused on a pedagogy for diverse learners, and on a consistent and explicitly inclusive policy framework centred on children’s rights.

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Familial expansile osteolysis (FEO) is a rare disorder causing bone dysplasia. The clinical features of FEO include early-onset hearing loss, tooth destruction, and progressive lytic expansion within limb bones causing pain, fracture, and deformity. An 18-bp duplication in the first exon of the TNFRSF11A gene encoding RANK has been previously identified in four FEO pedigrees. Despite having the identical mutation, phenotypic variations among affected individuals of the same and different pedigrees were noted. Another 18-bp duplication, one base proximal to the duplication previously reported, was subsequently found in two unrelated FEO patients. Finally, mutations overlapping with the mutations found in the FEO pedigrees have been found in ESH and early-onset PDB pedigrees. An Iranian FEO pedigree that contains six affected individuals dispersed in three generations has previously been introduced; here, the clinical features of the proband are reported in greater detail, and the genetic defect of the pedigree is presented. Direct sequencing of the entire coding region and upstream and downstream noncoding regions of TNFRSF11A in her DNA revealed the same 18-bp duplication mutation as previously found in the four FEO pedigrees. Additionally, eight sequence variations as compared to the TNFRSF11A reference sequence were identified, and a haplotype linked to the mutation based on these variations was defined. Although the mutation in the Iranian and four of the previously described FEO pedigrees was the same, haplotypes based on the intragenic SNPs suggest that the mutations do not share a common descent.

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It is difficult, even excruciating, to imagine the staggering descent from high optimism to despondency experienced by many African Americans who lived between emancipation and the dawn of the twentieth century. For historians living in the post–civil rights era, recapturing the scale, velocity, and brutality of that dramatic fall has been hampered by two conceptual problems. The first of these, undergirded by prominent trends in the formerly “new” social history, is a widely shared enthusiasm for illuminating those hidden corners of daily life where men and women on the receiving end of Jim Crow continued to wield a degree of control. “Agency” has been the buzzword for a generation of scholarship that emphasizes the staying power and persistence of black Southerners in the face of relentless assaults on their social and economic status, their civil rights, and even, at times, their collective existence. This is, in many ways, an understandable reaction to an earlier consensus that relegated black historical initiative to the margins of a national fable cleansed of unseemly violence and sharp social conflict, but it can also be problematic.

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PURPOSE:
To investigate whether variation in the distribution of the risk allele frequency of the Y402H single-nucleotide polymorphism (SNP) across various ethnicities and geographic regions reflects differences in the prevalence of late age-related macular degeneration (AMD) in those ethnicities.

METHODS:
Published data were obtained via a systematic search. Study samples were grouped into clusters by ethnicity and geographic location and the Spearman correlation coefficient of the prevalence of late AMD and risk allele frequencies was calculated across clusters.

RESULTS:
Across all ethnicities, AMD prevalence was seen to increase with age. Populations of European descent had both higher risk allele frequencies and prevalence of late AMD than did Japanese, Chinese, and Hispanic descendants. Results for African descendants were anomalous: although allele frequency was similar to that in European populations, the age-specific prevalence of late AMD was considerably lower. The correlation coefficient for the association between allele frequency and AMD prevalence was 0.40 (95% confidence interval [CI] = -0.36 to 0.84, P = 0.28) in all populations combined and 0.71 (95% CI = 0.02-0.94, P = 0.04) when people of African descent were excluded.

CONCLUSIONS:
Evidence was found at the population level to support a positive association between the Y204H risk allele and the prevalence of AMD after exclusion of studies undertaken on persons of African ancestry. Data in African, Middle Eastern, and South American populations are needed to provide a better understanding of the association of late AMD genetic risk across ethnicities.

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Objectives: We sought to replicate the association between the kinesin-like protein 6 (KIF6) Trp719Arg polymorphism (rs20455), and clinical coronary artery disease (CAD).
Background: Recent prospective studies suggest that carriers of the 719Arg allele in KIF6 are at increased risk of clinical CAD compared with noncarriers.
Methods: The KIF6 Trp719Arg polymorphism (rs20455) was genotyped in 19 case-control studies of nonfatal CAD either as part of a genome-wide association study or in a formal attempt to replicate the initial positive reports.
Results: A total of 17,000 cases and 39,369 controls of European descent as well as a modest number of South Asians, African Americans, Hispanics, East Asians, and admixed cases and controls were successfully genotyped. None of the 19 studies demonstrated an increased risk of CAD in carriers of the 719Arg allele compared with noncarriers. Regression analyses and fixed-effects meta-analyses ruled out with high degree of confidence an increase of <2% in the risk of CAD among European 719Arg carriers. We also observed no increase in the risk of CAD among 719Arg carriers in the subset of Europeans with early-onset disease (younger than 50 years of age for men and younger than 60 years of age for women) compared with similarly aged controls as well as all non-European subgroups.
Conclusions: The KIF6 Trp719Arg polymorphism was not associated with the risk of clinical CAD in this large replication study.

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Infrequent and exceptional behaviours can provide insight into the ecology and physiology of a particular species. Here we examined extraordinarily deep (300-1250 m) and protracted (>1h) dives made by critically endangered leatherback turtles (Dermochelys coriacea) in the context of three previously suggested hypotheses: predator evasion, thermoregulation and exploration for gelatinous prey. Data were obtained via satellite relay data loggers attached to adult turtles at nesting beaches (N=11) and temperate foraging grounds (N=2), constituting a combined tracking period of 9.6 years (N=26,146 dives) and spanning the entire North Atlantic Ocean. Of the dives, 99.6% (N=26,051) were to depths <300 m with only 0.4% (N=95) extending to greater depths (subsequently termed 'deep dives'). Analysis suggested that deep dives: (1) were normally distributed around midday; (2) may exceed the inferred aerobic dive limit for the species; (3) displayed slow vertical descent rates and protracted durations; (4) were much deeper than the thermocline; and (5) occurred predominantly during transit, yet ceased once seasonal residence on foraging grounds began. These findings support the hypothesis that deep dives are periodically employed to survey the water column for diurnally descending gelatinous prey. If a suitable patch is encountered then the turtle may cease transit and remain within that area, waiting for prey to approach the surface at night. If unsuccessful, then migration may continue until a more suitable site is encountered. Additional studies using a meta-analytical approach are nonetheless recommended to further resolve this matter.

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Introduction: The most effective treatment for high altitude sickness is prompt descent. However, rapid descent is sometimes impossible and alternative solutions are desirable. Supplemental oxygen at ambient pressure and hyperbaric oxygen in a hyperbaric tent have both been demonstrated to improve symptoms and increase arterial oxygenation (SaO(2)) in those with high altitude sickness; however, their use in combination has not previously been described in a controlled study. Methods and Results: In this feasibility study, the SaO(2) of six healthy, well-acclimatized participants rose from 76.5 to 97.5% at 4900 m and 72.5 to 96.0% at 5700 m following the administration of oxygen via a nasal demand circuit (33 ml of oxygen per pulse) inside a hyperbaric tent (107 mmHg above ambient barometric pressure) (p

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We performed a meta-analysis of 14 genome-wide association studies of coronary artery disease (CAD) comprising 22,233 individuals with CAD (cases) and 64,762 controls of European descent followed by genotyping of top association signals in 56,682 additional individuals. This analysis identified 13 loci newly associated with CAD at P < 5 x 10(-8) and confirmed the association of 10 of 12 previously reported CAD loci. The 13 new loci showed risk allele frequencies ranging from 0.13 to 0.91 and were associated with a 6% to 17% increase in the risk of CAD per allele. Notably, only three of the new loci showed significant association with traditional CAD risk factors and the majority lie in gene regions not previously implicated in the pathogenesis of CAD. Finally, five of the new CAD risk loci appear to have pleiotropic effects, showing strong association with various other human diseases or traits.

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We performed a meta-analysis to estimate the magnitude of C3 gene polymorphism effects, and their possible mode of action, on age-related macular degeneration (AMD). The meta-analysis included 16 studies for rs2230199 and 7 studies for rs1047286. Data extraction and risk of bias assessments were performed in duplicate, and heterogeneity and publication bias were explored. There was moderate evidence for association between both polymorphisms and AMD in individuals of European descent. For rs2230199, patients with CG and GG genotypes were 1.44 (95% CI: 1.33 – 1.56) and 1.88 (95% CI: 1.59 – 2.23) times more likely to have AMD than patients with CC genotype. For rs1047286, those with GA and AA genotypes had 1.27 (95% CI: 1.15 – 1.41) and 1.70 (95% CI: 1.27 – 2.11) times higher risk of AMD than those with GG genotypes. These gene effects suggested an additive model. The population attributable risks for the GG/GC and AA/GA genotypes are approximately 5-10%. Stratification of studies on the basis of ethnicity indicates that these variants are very infrequent in Asian populations and the significance of the effect observed is based largely on the high frequency of these variants within individuals of European descent. This meta-analysis supports the association between C3 and AMD and provides a robust estimate of the genetic risk.

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This paper looks at inheritance through minimally-structured interviews with several generations of Kenyan families, seeking to explain that the how and why of poverty can be understood in the wider family context. Five main routes for ascending out of poverty were identified: (1) the gradual accumulation of resources due to income deriving from cash crops; (2) the gradual accumulation of resources due to income from non-farm work, including remittances from family member who have moved away for work; (3) the role of education, particularly skills training opposed to academic qualification, in helping provide employment; (4) accessing financial assets through support both from extended family members and from informal support mechanisms; (5) stability and benefits accruing from long-term strategic planning, including entrepreneurial activity. Both the ascent out of and the descent into poverty can be better conceived as processes, rather than due to chains of discrete events or specific ‘shocks’.

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Motivation: We study a stochastic method for approximating the set of local minima in partial RNA folding landscapes associated with a bounded-distance neighbourhood of folding conformations. The conformations are limited to RNA secondary structures without pseudoknots. The method aims at exploring partial energy landscapes pL induced by folding simulations and their underlying neighbourhood relations. It combines an approximation of the number of local optima devised by Garnier and Kallel (2002) with a run-time estimation for identifying sets of local optima established by Reeves and Eremeev (2004).

Results: The method is tested on nine sequences of length between 50 nt and 400 nt, which allows us to compare the results with data generated by RNAsubopt and subsequent barrier tree calculations. On the nine sequences, the method captures on average 92% of local minima with settings designed for a target of 95%. The run-time of the heuristic can be estimated by O(n2D?ln?), where n is the sequence length, ? is the number of local minima in the partial landscape pL under consideration and D is the maximum number of steepest descent steps in attraction basins associated with pL.