66 research outputs found
Greenberger-Horne-Zeilinger nonlocality for continuous variable systems
As a development of our previous work, this paper is concerned with the
Greenberger-Horne-Zeilinger (GHZ) nonlocality for continuous variable cases.
The discussion is based on the introduction of a pseudospin operator, which has
the same algebra as the Pauli operator, for each of the modes of a light
field. Then the Bell-CHSH (Clauser, Horne, Shimony and Holt) inequality is
presented for the modes, each of which has a continuous degree of freedom.
Following Mermin's argument, it is demonstrated that for -mode
parity-entangled GHZ states (in an infinite-dimensional Hilbert space) of the
light field, the contradictions between quantum mechanics and local realism
grow exponentially with , similarly to the usual -spin cases.Comment: RevTEX; comments are welcomed; new version with minor change
Dimensional Crossover of Dilute Neon inside Infinitely Long Single-Walled Carbon Nanotubes Viewed from Specific Heats
A simple formula for coordinates of carbon atoms in a unit cell of a
single-walled nanotube (SWNT) is presented and the potential of neon (Ne)
inside an infinitely long SWNT is analytically derived under the assumption of
pair-wise Lennard-Jones potential between Ne and carbon atoms. Specific heats
of dilute Ne inside infinitely long (5, 5), (10, 10), (15, 15) and (20, 20)
SWNT's are calculated at different temperatures. It is found that Ne inside
four kinds of nanotubes exhibits 3-dimensional (3D) gas behavior at high
temperature but different behaviors at low temperature: Ne inside (5, 5)
nanotube behaves as 1D gas but inside (10, 10), (15, 15), and (20, 20)
nanotubes behaves as 2D gas. Furthermore, at ultra low temperature, Ne inside
(5, 5) nanotube still displays 1D behavior but inside (10, 10), (15, 15), and
(20, 20) nanotubes behaves as lattice gas.Comment: 10 pages, 5 figure
Effects of viscous dissipation and boundary conditions on forced convection in a channel occupied by a saturated porous medium
Forced convection with viscous dissipation in a parallel plate channel filled by a saturated porous medium is investigated numerically. Three different viscous dissipation models are examined. Two different sets of wall conditions are considered: isothermal and isoflux. Analytical expressions are also presented for the asymptotic temperature profile and the asymptotic Nusselt number. With isothermal walls, the Brinkman number significantly influences the developing Nusselt number but not the asymptotic one. At constant wall heat flux, both the developing and the asymptotic Nusselt numbers are affected by the value of the Brinkman number. The Nusselt number is sensitive to the porous medium shape factor under all conditions considered
Effects of viscous dissipation and boundary conditions on forced convection in a channel occupied by a saturated porous medium
Forced convection with viscous dissipation in a parallel plate channel filled by a saturated porous medium is investigated numerically. Three different viscous dissipation models are examined. Two different sets of wall conditions are considered: isothermal and isoflux. Analytical expressions are also presented for the asymptotic temperature profile and the asymptotic Nusselt number. With isothermal walls, the Brinkman number significantly influences the developing Nusselt number but not the asymptotic one. At constant wall heat flux, both the developing and the asymptotic Nusselt numbers are affected by the value of the Brinkman number. The Nusselt number is sensitive to the porous medium shape factor under all conditions considered
Irrelevance of photon events distinguishability in a class of Bell experiments
We show that the possibility of distinguishing between single- and two-photon detection events, usually not met in the actual experiments, is not a necessary requirement for proof that the experiments of Alley and Shih [Phys. Rev. Lett. 61, 2921 (1988)] and Ou and Mandel [Phys. Rev. Lett. 61, 50 (1988)] are modulo a fair sampling assumption, valid tests of local realism. We also give the critical parameters for the experiments to be unconditional tests of local realism, and show that some other interesting phenomena (involving bosonic-type particle indistinguishability) can be observed during such tests
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
FTO genetic variants, dietary intake and body mass index: insights from 177,330 individuals.
FTO is the strongest known genetic susceptibility locus for obesity. Experimental studies in animals suggest the potential roles of FTO in regulating food intake. The interactive relation among FTO variants, dietary intake and body mass index (BMI) is complex and results from previous often small-scale studies in humans are highly inconsistent. We performed large-scale analyses based on data from 177,330 adults (154 439 Whites, 5776 African Americans and 17 115 Asians) from 40 studies to examine: (i) the association between the FTO-rs9939609 variant (or a proxy single-nucleotide polymorphism) and total energy and macronutrient intake and (ii) the interaction between the FTO variant and dietary intake on BMI. The minor allele (A-allele) of the FTO-rs9939609 variant was associated with higher BMI in Whites (effect per allele = 0.34 [0.31, 0.37] kg/m(2), P = 1.9 × 10(-105)), and all participants (0.30 [0.30, 0.35] kg/m(2), P = 3.6 × 10(-107)). The BMI-increasing allele of the FTO variant showed a significant association with higher dietary protein intake (effect per allele = 0.08 [0.06, 0.10] %, P = 2.4 × 10(-16)), and relative weak associations with lower total energy intake (-6.4 [-10.1, -2.6] kcal/day, P = 0.001) and lower dietary carbohydrate intake (-0.07 [-0.11, -0.02] %, P = 0.004). The associations with protein (P = 7.5 × 10(-9)) and total energy (P = 0.002) were attenuated but remained significant after adjustment for BMI. We did not find significant interactions between the FTO variant and dietary intake of total energy, protein, carbohydrate or fat on BMI. Our findings suggest a positive association between the BMI-increasing allele of FTO variant and higher dietary protein intake and offer insight into potential link between FTO, dietary protein intake and adiposity
Detectable clonal mosaicism and its relationship to aging and cancer
In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases
An integrative tool for gene regulatory network reconstruction based on microarray data
[[abstract]]The transcriptional regulation of gene expression has been known to be a key mechanism in the functioning of the cell and the gene expression is influenced by the transcriptional regulatory strengths. In this paper we extend the function of a former proposed gene expression analysis tool named Gene Expression Explorer to include the gene regulatory network reconstruction based on microarray data. The regulatory strengths between transcription factors and genes are implemented by a modified network component analysis method where the genes expression relationships between genes vs. tissues and transcription factors vs. tissues are adopted to explore the regulatory strengths between genes and various transcription factors. Visualized presentation of the proposed tool clearly illustrates the regulatory patterns of transcription factors for each related gene. The biologists could benefit from using this tool to analyze the gene regulatory network based on microarray data. © 2009 IEEE
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