363 research outputs found

    The Classification of the Largest Caps in AG(5, 3)

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    AbstractWe prove that 45 is the size of the largest caps in AG(5,3), and such a 45-cap is always obtained from the 56-cap in PG(5,3) by deleting an 11-hyper-plane

    SDL - The IoT Language

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    Interconnected smart devices constitute a large and rapidly growing element of the contemporary Internet. A smart thing can be as simple as a web-enabled device that collects and transmits sensor data to a repository for analysis, or as complex as a web-enabled system to monitor and manage a smart home. Smart things present marvellous opportunities, but when they participate in complex systems, they challenge our ability to manage risk and ensure reliability. SDL, the ITU Standard Specification and Description Language, provides many advantages for modelling and simulating communicating agents – such as smart things – before they are deployed. The potential for SDL to enhance reliability and safety is explored with respect to existing smart things below. But SDL must advance if it is to become the language of choice for developing the next generation of smart things. In particular, it must target emerging IoT platforms, it must support simulation of interactions between pre-existing smart things and new smart things, and it must facilitate deployment of large numbers of similar things. Moreover, awareness of the potential benefits of SDL must be raised if those benefits are to be realized in the current and future Internet of Things.Peer ReviewedPostprint (published version

    Fluorescence detection methods for microfluidic droplet platforms

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    The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that accompany system miniaturisation. Advantages include the ability to efficiently process nano- to femoto- liter volumes of sample, facile integration of functional components, an intrinsic predisposition towards large-scale multiplexing, enhanced analytical throughput, improved control and reduced instrumental footprints.

    The emergence of international food safety standards and guidelines: understanding the current landscape through a historical approach

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    Following the Second World War, the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) teamed up to construct an International Codex Alimentarius (or 'food code') which emerged in 1963. The Codex Committee on Food Hygiene (CCFH) was charged with the task of developing microbial hygiene standards, although it found itself embroiled in debate with the WHO over the nature these standards should take. The WHO was increasingly relying upon the input of biometricians and especially the International Commission on Microbial Specifications for Foods (ICMSF) which had developed statistical sampling plans for determining the microbial counts in the final end products. The CCFH, however, was initially more focused on a qualitative approach which looked at the entire food production system and developed codes of practice as well as more descriptive end-product specifications which the WHO argued were 'not scientifically correct'. Drawing upon historical archival material (correspondence and reports) from the WHO and FAO, this article examines this debate over microbial hygiene standards and suggests that there are many lessons from history which could shed light upon current debates and efforts in international food safety management systems and approaches

    Plant hormones increase efficiency of reprogramming mouse somatic cells to induced pluripotent stem cells and reduce tumorigenicity

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    Reprogramming of somatic cells into induced pluripotent stem (iPS) cells by defined pluripotency and self-renewal factors has taken stem cell technology to the forefront of regenerative medicine. However, a number of challenges remain in the field including efficient protocols and the threat of cancer. Reprogramming of plant somatic cells to plant embryonic stem cells using a combination of two plant hormones was discovered in 1957 and has been a routine university laboratory practical for over 30 years. The plant hormones responsible for cell reprogramming to pluripotency, indole-3-acetic acid (IAA) and isopentenyl adenosine (IPA), are present in human cells, leading to the exciting possibility that plant hormones might reprogram mammalian cells without genetic factors. We found that plant hormones on their own could not reprogram mammalian cells but increase the efficiency of the early formation of iPS cells combined with three defined genetic factors during the first 3 weeks of reprogramming by accelerating the cell cycle and regulating pluripotency genes. Moreover, the cytokinin IPA, a known human anticancer agent, reduced the threat of cancer of iPS cell in vitro by regulating key cancer and stem cell-related genes, most notably c-Myc and Igf-1. In conclusion, the plant hormones, auxin and cytokinin, are new small chemicals useful for enhancing early reprogramming efficiency of mammalian cells and reducing the threat of cancer from iPS cells. These findings suggest a novel role for plant hormones in the biology of mammalian cell plasticit

    Quasi-free π0\pi^0 Photoproduction from the Bound Nucleon

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    Differential cross-sections for quasi-free π0\pi^0 photoproduction from the proton and neutron bound in the deuteron have been measured for EÎł=200−400E_\gamma= 200 - 400 MeV at Ξγlab=136.2∘\theta^{\rm lab}_\gamma = 136.2^\circ usind the Glasgow photon tagger at MAMI, the Mainz 48 cm ∅\varnothing ×\times 64 cm NaI(Tl) photon detector and the G\"ottingen SENECA recoil detector. For the proton measurements made with both liquid deuterium and liquid hydrogen targets allow direct comparison of "free" π0\pi^0 photoproduction cross-sections as extracted from the bound proton data with experimental free cross sections which are found to be in reasonable agreement below 320 MeV. At higher energies the "free" cross sections extracted from quasifree data are significantly smaller than the experimental free cross sections and theoretical predictions based on multipole analysis. For the first time, "free" neutron cross sections have been extracted in the Δ\Delta-region. They are also in agreement with the predictions from multipole analysis up to 320 MeV and significantly smaller at higher photon energies

    Accuracy of genomic BLUP when considering a genomic relationship matrix based on the number of the largest eigenvalues: a simulation study.

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    International audienceAbstractBackgroundThe dimensionality of genomic information is limited by the number of independent chromosome segments (Me), which is a function of the effective population size. This dimensionality can be determined approximately by singular value decomposition of the gene content matrix, by eigenvalue decomposition of the genomic relationship matrix (GRM), or by the number of core animals in the algorithm for proven and young (APY) that maximizes the accuracy of genomic prediction. In the latter, core animals act as proxies to linear combinations of Me. Field studies indicate that a moderate accuracy of genomic selection is achieved with a small dataset, but that further improvement of the accuracy requires much more data. When only one quarter of the optimal number of core animals are used in the APY algorithm, the accuracy of genomic selection is only slightly below the optimal value. This suggests that genomic selection works on clusters of Me.ResultsThe simulation included datasets with different population sizes and amounts of phenotypic information. Computations were done by genomic best linear unbiased prediction (GBLUP) with selected eigenvalues and corresponding eigenvectors of the GRM set to zero. About four eigenvalues in the GRM explained 10% of the genomic variation, and less than 2% of the total eigenvalues explained 50% of the genomic variation. With limited phenotypic information, the accuracy of GBLUP was close to the peak where most of the smallest eigenvalues were set to zero. With a large amount of phenotypic information, accuracy increased as smaller eigenvalues were added.ConclusionsA small amount of phenotypic data is sufficient to estimate only the effects of the largest eigenvalues and the associated eigenvectors that contain a large fraction of the genomic information, and a very large amount of data is required to estimate the remaining eigenvalues that account for a limited amount of genomic information. Core animals in the APY algorithm act as proxies of almost the same number of eigenvalues. By using an eigenvalues-based approach, it was possible to explain why the moderate accuracy of genomic selection based on small datasets only increases slowly as more data are added

    Accounting for genomic pre-selection in national BLUP evaluations in dairy cattle

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    <p>Abstract</p> <p>Background</p> <p>In future Best Linear Unbiased Prediction (BLUP) evaluations of dairy cattle, genomic selection of young sires will cause evaluation biases and loss of accuracy once the selected ones get progeny.</p> <p>Methods</p> <p>To avoid such bias in the estimation of breeding values, we propose to include information on all genotyped bulls, including the culled ones, in BLUP evaluations. Estimated breeding values based on genomic information were converted into genomic pseudo-performances and then analyzed simultaneously with actual performances. Using simulations based on actual data from the French Holstein population, bias and accuracy of BLUP evaluations were computed for young sires undergoing progeny testing or genomic pre-selection. For bulls pre-selected based on their genomic profile, three different types of information can be included in the BLUP evaluations: (1) data from pre-selected genotyped candidate bulls with actual performances on their daughters, (2) data from bulls with both actual and genomic pseudo-performances, or (3) data from all the genotyped candidates with genomic pseudo-performances. The effects of different levels of heritability, genomic pre-selection intensity and accuracy of genomic evaluation were considered.</p> <p>Results</p> <p>Including information from all the genotyped candidates, i.e. genomic pseudo-performances for both selected and culled candidates, removed bias from genetic evaluation and increased accuracy. This approach was effective regardless of the magnitude of the initial bias and as long as the accuracy of the genomic evaluations was sufficiently high.</p> <p>Conclusions</p> <p>The proposed method can be easily and quickly implemented in BLUP evaluations at the national level, although some improvement is necessary to more accurately propagate genomic information from genotyped to non-genotyped animals. In addition, it is a convenient method to combine direct genomic, phenotypic and pedigree-based information in a multiple-step procedure.</p

    Helios expression coordinates the development of a subset of striatopallidal medium spiny neurons

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    Here we unravel the mechanism of action of Helios (He) during the development of striatal medium spiny neurons (MSNs). He regulates the second wave of striatal neurogenesis involved in the generation of striatopallidal neurons that express dopamine 2 receptor (D2R) and enkephalin (ENK). To exert this effect He is expressed in neural progenitor cells (NPCs) retaining them into the G1/G0 phase of the cell cycle. Thus, the lack of He produces an increase of S-phase entry and S-phase length of NPCs which in turn impairs striatal neurogenesis and produces an accumulation of the number of cycling NPCs in the germinal zone (GZ) that end up dying at postnatal stages. Therefore, He-/- mice show a reduction in the number of Dorso-Medial Striatal MSNs in the adulthood that produces deficits in motor skills acquisition. In addition, overexpression of He in NPCs induce DARPP32 phenotype when transplanted in mouse striatum.Present findings demonstrate that He is involved in the correct development of a subset of striatopallidal MSNs and reveal new cellular mechanisms for neuronal development
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