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Search Results: 1 - 10 of 55533 matches for " Y; Nicholas "
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Family-based association analysis of alcohol dependence implicates KIAA0040 on Chromosome 1q in multiplex alcohol dependence families  [PDF]
Shirley Y. Hill, Bobby L. Jones, Nicholas Zezza, Scott Stiffler
Open Journal of Genetics (OJGen) , 2013, DOI: 10.4236/ojgen.2013.34027
Abstract:

Background: A previous genome-wide linkage study of alcohol dependence in multiplex families found a suggestive linkage result for a region on Chromosome 1 near microsatellite markers D1S196 and D1S2878. The KIAA0040 gene has been mapped to this region (1q24-q25). A recent genome-wide association study using SAGE (the Study of Addiction: Genetics and Environment) and COGA (Collaborative Study on the Genetics of Alcoholism) found five SNPs within the KIAA0040 gene significantly associated with alcohol dependence. A meta-analysis using data from these sources also found the KIAA0040 gene significantly associated with alcohol dependence. Methods: Using family data consisting of 1000 individuals with phenotypic data (762 with both phenotype and DNA), finer mapping of a 0.3 cM region that included the KIAA0040 gene and a flanking gene was undertaken using SNPs with minor allele frequency (MAF) ≥ 0.15 and pair-wise linkage disequilibrium (LD) of r2 < 0.8 using the HapMap CEU population. Results: Significant FBAT p-values were observed for six SNPs, four within the KIAA0040 gene (rs2269650, rs2861158, rs1008459, rs2272785) and two adjacent to KIAA0040 (rs10912899 and rs3753555). Five haplotype blocks of varying size were identified using HAPLOVIEW. Analysis using the haplotype-based test function of FBAT revealed one two-SNP block (rs1008459rs2272785) associated with alcohol dependence. This block showed a pattern of transmission in which one haplotype, CT, with a frequency of 0.577 was found to be over-transmitted to affected offspring (p = 0.017) while another haplotype, AG, with a frequency of 0.238 was found to be under-transmitted to affected offspring (p = 0.006). A three-SNP block (rs1008459rs2272785-rs375355) showed an overall significant association (p = 0.011) with alcohol dependence with the haplotype ACT over-transmitted to affected offspring (p = 0.016) and the haplotype GAG undertransmitted (p = 0.002). Conclusions: Family-based association analysis shows the KIAA0040 gene significantly associated with alcohol dependence. The potential importance of the KIAA0040 gene for AD risk is currently unknown. However, the present results support earlier findings from a genome-wide association study.

Cooling and Heating Functions of Photoionized Gas
Nickolay Y. Gnedin,Nicholas Hollon
Physics , 2012, DOI: 10.1088/0067-0049/202/2/13
Abstract: Cooling and heating functions of cosmic gas are a crucial ingredient for any study of gas dynamics and thermodynamics in the interstellar and intergalactic medium. As such, they have been studied extensively in the past under the assumption of collisional ionization equilibrium. However, for a wide range of applications, the local radiation field introduces a non-negligible, often dominant, modification to the cooling and heating functions. In the most general case, these modifications cannot be described in simple terms, and would require a detailed calculation with a large set of chemical species using a radiative transfer code (the well-known code Cloudy, for example). We show, however, that for a sufficiently general variation in the spectral shape and intensity of the incident radiation field, the cooling and heating functions can be approximated as depending only on several photoionization rates, which can be thought of as representative samples of the overall radiation field. This dependence is easy to tabulate and implement in cosmological or galactic-scale simulations, thus economically accounting for an important but rarely-included factor in the evolution of cosmic gas. We also show a few examples where the radiation environment has a large effect, the most spectacular of which is a quasar that suppresses gas cooling in its host halo without any mechanical or non-radiative thermal feedback.
The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance
Bhatt,A; Naidoo,Y; Nicholas,A;
Biological Research , 2010, DOI: 10.4067/S0716-97602010000400004
Abstract: the micromorphology of foliar trichomes of hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (sem). this genus belongs to the advanced angiosperm family acanthaceae, for which few micromorphological leaf studies exist. results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. with leaf maturity, the density of non-glandular trichomes decreased. glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.
The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance
A Bhatt,Y Naidoo,A Nicholas
Biological Research , 2010,
Abstract: The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM). This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.
Disordered Kondo Nanoclusters: Effect of Energy Spacing
C. Verdozzi,Y. Luo,Nicholas Kioussis
Physics , 2003, DOI: 10.1103/PhysRevB.70.132404
Abstract: Exact diagonalization results for Kondo nanoclusters alloyed with mixed valence impurities show that tuning the {\it energy spacing}, $\Delta$, drives the system from the Kondo to the RKKY regime. The interplay of $\Delta$ and disorder gives rise to a $\Delta$ versus concentration T=0 phase diagram very rich in structure, where regions with prevailing Kondo or RKKY correlations alternate with domains of ferromagnetic order. The local Kondo temperatures, $T_K$, and RKKY interactions depend strongly on the local environment and are overall {\it enhanced} by disorder, in contrast to the hypothesis of ``Kondo disorder'' single-impurity models.
Reducing pervasive false positive identical-by-descent segments detected by large-scale pedigree analysis
Eric Y. Durand,Nicholas Eriksson,Cory Y. McLean
Quantitative Biology , 2013,
Abstract: Analysis of genomic segments shared identical-by-descent (IBD) between individuals is fundamental to many genetic applications, from demographic inference to estimating the heritability of diseases, but IBD detection accuracy in non-simulated data is largely unknown. In principle, it can be evaluated using known pedigrees, as IBD segments are by definition inherited without recombination down a family tree. We extracted 25,432 genotyped European individuals containing 2,952 father-mother-child trios from the 23andMe, Inc. dataset. We then used GERMLINE, a widely used IBD detection method, to detect IBD segments within this cohort. Exploiting known familial relationships, we identified a false positive rate over 67% for 2-4 centiMorgan (cM) segments, in sharp contrast with accuracies reported in simulated data at these sizes. Nearly all false positives arose from the allowance of haplotype switch errors when detecting IBD, a necessity for retrieving long (> 6 cM) segments in the presence of imperfect phasing. We introduce HaploScore, a novel, computationally efficient metric that scores IBD segments proportional to the number of switch errors they contain. Applying HaploScore filtering to the IBD data at a precision of 0.8 produced a 13-fold increase in recall when compared to length-based filtering. We replicate the false IBD findings and demonstrate the generalizability of HaploScore to alternative data sources using an independent cohort of 555 European individuals from the 1000 Genomes project. HaploScore can improve the accuracy of segments reported by any IBD detection method, provided that estimates of the genotyping error rate and switch error rate are available.
Three Philosophical Problems about Consciousness and their Possible Resolution  [PDF]
Nicholas Maxwell
Open Journal of Philosophy (OJPP) , 2011, DOI: 10.4236/ojpp.2011.11001
Abstract: Three big philosophical problems about consciousness are: Why does it exist? How do we explain and understand it? How can we explain brain-consciousness correlations? If functionalism were true, all three problems would be solved. But it is false, and that means all three problems remain unsolved (in that there is no other obvious candidate for a solution). Here, it is argued that the first problem cannot have a solution; this is inherent in the nature of explanation. The second problem is solved by recognizing that (a) there is an explanation as to why science cannot explain consciousness, and (b) consciousness can be explained by a different kind of explanation, empathic or “personalistic” explanation, compatible with, but not reducible to, scientific explanation. The third problem is solved by exploiting David Chalmers“principle of structural coherence”, and involves postulating that sensations experienced by us–visual, auditory, tactile, and so on–amount to minute scattered regions in a vast, multi dimensional “space” of all possible sensations, which vary smoothly, and in a linear way, throughout the space. There is also the space of all possible sentient brain processes. There is just one, unique one-one mapping between these two spaces that preserves continuity and linearity. It is this which provides the explanation as to why brain processes and sensations are correlated as they are. I consider objections to this unique-matching theory, and consider how the theory might be empirically confirmed.
Origins and Mechanisms in the Development of Major Mental Disorders: A Clinical Approach  [PDF]
Nicholas Pediaditakis
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.22030
Abstract: This paper considers the following collective significance of the shared, clinical characteristics of the major mental disorders (MMDs), their co-morbidities, overlaps and pharmacological responses with the following conclusions: 1) These disorders have a common, initial, neurodevelopmental origin. 2) They can occur probabilistically on susceptible individuals, on account of pre-existing, extreme, temperamental variances-signifying underlying structural variance. 3) Each of these syndromes can be considered the expression of disturbances in the overall, common, operating mode of brain function which normally ensures the synchrony, coordination, elegance and subtlety in the expression of all the brain’s higher faculties. 4) Lastly, this function is a complex, emergent phenomenon based on the individual’s temperamental/structural underlying makeup, switching intermittently from a normal phase to a pathologically, ordered one-the latter phase expressing itself with symptoms made up of expressing either/or, antithetical substitutes for each of the MMDs-similar to the fluctuations found in patient’s with Parkinson’s disease.
Origins and Mechanisms in the Development of Major Mental Disorders: A Clinical Approach  [PDF]
Nicholas Pediaditakis
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.22030
Abstract: This paper considers the following collective significance of the shared, clinical characteristics of the major mental disorders (MMDs), their co-morbidities, overlaps and pharmacological responses with the following conclusions: 1) These disorders have a common, initial, neurodevelopmental origin. 2) They can occur probabilistically on susceptible individuals, on account of pre-existing, extreme, temperamental variances-signifying underlying structural variance. 3) Each of these syndromes can be considered the expression of disturbances in the overall, common, operating mode of brain function which normally ensures the synchrony, coordination, elegance and subtlety in the expression of all the brain’s higher faculties. 4) Lastly, this function is a complex, emergent phenomenon based on the individual’s temperamental/structural underlying makeup, switching intermittently from a normal phase to a pathologically, ordered one-the latter phase expressing itself with symptoms made up of expressing either/or, antithetical substitutes for each of the MMDs-similar to the fluctuations found in patient’s with Parkinson’s disease.
Three Criticisms of Newton’s Inductive Argument in the Principia  [PDF]
Nicholas Maxwell
Advances in Historical Studies (AHS) , 2014, DOI: 10.4236/ahs.2014.31002
Abstract: In this paper, I discuss how Newton’s inductive argument of the Principia can be defended against criticisms leveled against it by Duhem, Popper and myself. I argue that Duhem’s and Popper’s criticisms can be countered, but mine cannot. It requires that we reconsider, not just Newton’s inductive argument in the Principia, but also the nature of science more generally. The methods of science, whether conceived along inductivist or hypothetico-deductivist lines, make implicit metaphysical presuppositions which rigorously require us to make them explicit within science so that they can be critically assessed, alternatives being developed and assessed, in the hope that they can be improved. Despite claiming to derive his law of gravitation by induction from phenomena without resource to hypotheses, Newton does nevertheless acknowledge in the Principia that his rules of reasoning make metaphysical presuppositions. To this extent, Newton has a more enlightened view of scientific method than most 20th and 21st century scientists and historians and philosophers of science.
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