583 research outputs found

    Experimental control of pattern formation by photonic lattices

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    We study the control of modulational instability and pattern formation in a nonlinear dissipative feedback system with a periodic modulation of the material refractive index. We use a one-dimensional photonic lattice in a single-mirror feedback configuration and identify three mechanisms for pattern control: bandgap suppression of instability modes, periodicity induced pattern modes, and orientational pattern control.The authors acknowledge the support of the Conseil Régional de Lorraine, the bilateral FrenchAustralian Science and Technology program, and the Australian Research Council through Discovery projects

    Dinamika Perubahan Komposisi Gulma Pada Tanaman Tebu Keprasan Di Lahan Sistem Reynoso Dan Tegalan

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    Gulma adalah komponen yang tetap pada agroekosistem. Penelitian ini dilakukan un-tuk mempelajari Perubahan komposisi gul-ma pada tanaman tebu keprasan di lahan sistem reynoso dan tegalan. Penelitian ini dilaksanakan pada bulan Januari sampai Mei 2014 di Desa Legundi, Kecamatan Karang Jati, Kabupaten Ngawi. Hasil penelitian menunjukkan bahwa terdapat 35 spesies gulma yang ada di lahan sistem reynoso. Gulma yang mendominasi di lahan sistem reynoso adalah Chromolaena odorata (kirinyu), Ipomoea triloba (rayutan), Cayratia trifolia (galing-galing) dan Phyllanthus niruri (meniran). Gulma yang tersusun di lahan tegalan terdapat 33 spesies. Gulma yang mendominasi di lahan tegalan adalah Digitaria sanguinalis (jam-pang piit), Brachiaria distachya (gajihan) dan Ageratum conyzoides (wedusan). Nilai Indeks Shanon-Wienner berkisar antara 2,66-3,20 yang berarti tingkat keaneka-ragaman gulma pada lahan penelitian tergolong dalam kategori sedang. Nilai Indeks Simpson berkisar antara 0,05-0,13 yang berarti struktur komunitas dalam keadaan stabil dan tidak terjadi dominasi individu spesies gulma pada lahan penelitian. Nilai Indeks Sebaran Morisita (Id) pada lahan penelitian berkisar antara 0,00-12,28. Pola sebaran gulma di lahan sistem reynoso cenderung berkelompok dan merata, sedangkan di lahan tegalan gulma cenderung memiliki pola sebaran berkelompok

    Amorphous topological matter: theory and experiment

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    Topological phases of matter are ubiquitous in crystals, but less is known about their existence in amorphous systems, that lack long-range order. In this perspective, we review the recent progress made on theoretically defining amorphous topological phases and the new phenomenology that they can open. We revisit key experiments suggesting that amorphous topological phases exist in both solid-state and synthetic amorphous systems. We finish by discussing the open questions in the field, that promises to significantly enlarge the set of materials and synthetic systems benefiting from the robustness of topological matter.Comment: This is an extended version of the article accepted in EP

    Validation of the log e–log σ normal compression law using particle strength data

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    This note is a study of experimental data on particle strength and normal compression, to establish whether the recently proposed normal compression law by McDowell and de Bono (2013) is supported and confirmed. A number of different sands are examined and found to support the hypothesis. In addition, some new simulations on sand mixtures are used to explain experimental results for quartz-feldspar mixtures. It would appear that the proposed compression law is also supported by the data for the sand mixtures

    CNstream: A method for the identification and genotyping of copy number polymorphisms using Illumina microarrays

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    <p>Abstract</p> <p>Background</p> <p>Understanding the genetic basis of disease risk in depth requires an exhaustive knowledge of the types of genetic variation. Very recently, Copy Number Variants (CNVs) have received much attention because of their potential implication in common disease susceptibility. Copy Number Polymorphisms (CNPs) are of interest as they segregate at an appreciable frequency in the general population (i.e. > 1%) and are potentially implicated in the genetic basis of common diseases.</p> <p>Results</p> <p>This paper concerns CNstream, a method for whole-genome CNV discovery and genotyping, using Illumina Beadchip arrays. Compared with other methods, a high level of accuracy was achieved by analyzing the measures of each intensity channel separately and combining information from multiple samples. The CNstream method uses heuristics and parametrical statistics to assign a confidence score to each sample at each probe; the sensitivity of the analysis is increased by jointly calling the copy number state over a set of nearby and consecutive probes. The present method has been tested on a real dataset of 575 samples genotyped using Illumina HumanHap 300 Beadchip, and demonstrates a high correlation with the Database of Genomic Variants (DGV). The same set of samples was analyzed with PennCNV, one of the most frequently used copy number inference methods for Illumina platforms. CNstream was able to identify CNP loci that are not detected by PennCNV and it increased the sensitivity over multiple other loci in the genome.</p> <p>Conclusions</p> <p>CNstream is a useful method for the identification and characterization of CNPs using Illumina genotyping microarrays. Compared to the PennCNV method, it has greater sensitivity over multiple CNP loci and allows more powerful statistical analysis in these regions. Therefore, CNstream is a robust CNP analysis tool of use to researchers performing genome-wide association studies (GWAS) on Illumina platforms and aiming to identify CNVs associated with the variables of interest. CNstream has been implemented as an R statistical software package that can work directly from raw intensity files generated from Illumina GWAS projects. The method is available at <url>http://www.urr.cat/cnv/cnstream.html</url>.</p

    Microcrystalline silicon thin film transistors obtained by Hot-Wire CVD

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    Polysilicon thin film transistors (TFT) are of great interest in the field of large area microelectronics, especially because of their application as active elements in flat panel displays. Different deposition techniques are in tough competition with the objective to obtain device-quality polysilicon thin films at low temperature. In this paper we present the preliminary results obtained with the fabrication of TFT deposited by hot-wire chemical vapor deposition (HWCVD). Some results concerned with the structural characterization of the material and electrical performance of the device are presented

    A common copy-number variant within SIRPB1 correlates with human Out-of-Africa migration after genetic drift correction

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    Previous reports have proposed that personality may have played a role on human Out-Of- Africa migration, pinpointing some genetic variants that were positively selected in the migrating populations. In this work, we discuss the role of a common copy-number variant within the SIRPB1 gene, recently associated with impulsive behavior, in the human Out-Of-Africa migration. With the analysis of the variant distribution across forty-two different populations, we found that the SIRPB1 haplotype containing duplicated allele significantly correlated with human migratory distance, being one of the few examples of positively selected loci found across the human world colonization. Circular Chromosome Conformation Capture (4C-seq) experiments from the SIRPB1 promoter revealed important 3D modifications in the locus depending on the presence or absence of the duplication variant. In addition, a 3' enhancer showed neural activity in transgenic models, suggesting that the presence of the CNV may compromise the expression of SIRPB1 in the central nervous system, paving the way to construct a molecular explanation of the SIRPB1 variants role in human migration

    Thin Film Transistors obtained by Hot-Wire CVD

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    Hydrogenated microcrystalline silicon films obtained at low temperature (150-280°C) by hot wire chemical vapour deposition at two different process pressures were measured by Raman spectroscopy, X-ray diffraction (XRD) spectroscopy and photothermal deflection spectroscopy (PDS). A crystalline fraction >90% with a subgap optical absortion 10 cm -1 at 0.8 eV were obtained in films deposited at growth rates >0.8 nm/s. These films were incorporated in n-channel thin film transistors and their electrical properties were measured. The saturation mobility was 0.72 ± 0.05 cm 2/ V s and the threshold voltage around 0.2 eV. The dependence of their conductance activation energies on gate voltages were related to the properties of the material
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