2,348 research outputs found
A New Type of distributed Enamel based Clearing Electrode
Clearing electrodes can be used for electron cloud (EC) suppression in high intensity particle accelerators. In this paper the use of low and highly resistive layers on a dielectric substrate are examined. The beam coupling impedance of such a structure is evaluated. Furthermore the clearing efficiency as well as technological issues are discussed
The Utility of Graph Clustering of 5S Ribosomal DNA Homoeologs in Plant Allopolyploids, Homoploid Hybrids, and Cryptic Introgressants
Introduction: Ribosomal DNA (rDNA) loci have been widely used for identification of
allopolyploids and hybrids, although few of these studies employed high-throughput
sequencing data. Here we use graph clustering implemented in the RepeatExplorer (RE)
pipeline to analyze homoeologous 5S rDNA arrays at the genomic level searching for
hybridogenic origin of species. Data were obtained from more than 80 plant species,
including several well-defined allopolyploids and homoploid hybrids of different
evolutionary ages and from widely dispersed taxonomic groups.
Results: (i) Diploids show simple circular-shaped graphs of their 5S rDNA clusters. In
contrast, most allopolyploids and other interspecific hybrids exhibit more complex graphs
composed of two or more interconnected loops representing intergenic spacers (IGS). (ii)
There was a relationship between graph complexity and locus numbers. (iii) The
sequences and lengths of the 5S rDNA units reconstituted in silico from k-mers were
congruent with those experimentally determined. (iv) Three-genomic comparative cluster
analysis of reads from allopolyploids and progenitor diploids allowed identification of
homoeologous 5S rRNA gene families even in relatively ancient (c. 1 Myr) Gossypium and
Brachypodium allopolyploids which already exhibit uniparental partial loss of rDNA
repeats. (v) Finally, species harboring introgressed genomes exhibit exceptionally
complex graph structures.
Conclusion: We found that the cluster graph shapes and graph parameters (k-mer
coverage scores and connected component index) well-reflect the organization and
intragenomic homogeneity of 5S rDNA repeats. We propose that the analysis of 5S rDNA
cluster graphs computed by the RE pipeline together with the cytogenetic analysis might
be a reliable approach for the determination of the hybrid or allopolyploid plant species
parentage and may also be useful for detecting historical introgression events
Probabilistic analysis of COVID-19 patients' individual length of stay in Swiss intensive care units
RATIONALE
The COVID-19 pandemic induces considerable strain on intensive care unit resources.
OBJECTIVES
We aim to provide early predictions of individual patients' intensive care unit length of stay, which might improve resource allocation and patient care during the on-going pandemic.
METHODS
We developed a new semiparametric distributional index model depending on covariates which are available within 24h after intensive care unit admission. The model was trained on a large cohort of acute respiratory distress syndrome patients out of the Minimal Dataset of the Swiss Society of Intensive Care Medicine. Then, we predict individual length of stay of patients in the RISC-19-ICU registry.
MEASUREMENTS
The RISC-19-ICU Investigators for Switzerland collected data of 557 critically ill patients with COVID-19.
MAIN RESULTS
The model gives probabilistically and marginally calibrated predictions which are more informative than the empirical length of stay distribution of the training data. However, marginal calibration was worse after approximately 20 days in the whole cohort and in different subgroups. Long staying COVID-19 patients have shorter length of stay than regular acute respiratory distress syndrome patients. We found differences in LoS with respect to age categories and gender but not in regions of Switzerland with different stress of intensive care unit resources.
CONCLUSION
A new probabilistic model permits calibrated and informative probabilistic prediction of LoS of individual patients with COVID-19. Long staying patients could be discovered early. The model may be the basis to simulate stochastic models for bed occupation in intensive care units under different casemix scenarios
Context-Awareness at the Service of Sensor Fusion Systems: Inverting the Usual Scheme
Proceedings of: 11th International Work-Conference on Artificial Neural Networks (IWANN 2011). International Workshop of Intelligent systems for context-based information fusion (ISCIF 11). Torremolinos-Málaga, Spain, June 8-10, 2011Many works on context-aware systems make use of location, navigation or tracking services offered by an underlying sensor fusion module, as part of the relevant contextual information. The obtained knowledge is typically consumed only by the high level layers of the system, in spite that context itself represents a valuable source of information from which every part of the implemented system could take benefit. This paper closes the loop, analyzing how can context knowledge be applied to improve the accuracy, robustness and adaptability of sensor fusion processes. The whole theoretical analysis will be related with the indoor/outdoor navigation system implemented for a wheeled robotic platform. Some preliminary results are presented, where the context information provided by a map is integrated in the sensor fusion system.This work was supported in part by Projects ATLANTIDA, CICYT TIN2008-06742-C02-02/TSI, CICYT TEC2008-06732-C02-02/TEC, SINPROB, CAM MADRINET S-0505/TIC/0255 DPS2008-07029-C02-02.Publicad
Обоснование выбора электродвигателя и схемы его включения для системы точного поддержания скорости
Рассматривается применение в системах точного поддержания скорости различных синхронных электродвигателей. В результате сравнения рекомендовано применение в таких системах конденсаторного синхронного реактивного двигателя с трехфазными обмотками статора. Это позволяет упростить и удешевить систему точного электропривода и повысить ее надежность
The Evolution of Spinnable Cotton Fiber Entailed Prolonged Development and a Novel Metabolism
A central question in evolutionary biology concerns the developmental processes by which new phenotypes arise. An exceptional example of evolutionary innovation is the single-celled seed trichome in Gossypium (“cotton fiber”). We have used fiber development in Gossypium as a system to understand how morphology can rapidly evolve. Fiber has undergone considerable morphological changes between the short, tightly adherent fibers of G. longicalyx and the derived long, spinnable fibers of its closest relative, G. herbaceum, which facilitated cotton domestication. We conducted comparative gene expression profiling across a developmental time-course of fibers from G. longicalyx and G. herbaceum using microarrays with ∼22,000 genes. Expression changes between stages were temporally protracted in G. herbaceum relative to G. longicalyx, reflecting a prolongation of the ancestral developmental program. Gene expression and GO analyses showed that many genes involved with stress responses were upregulated early in G. longicalyx fiber development. Several candidate genes upregulated in G. herbaceum have been implicated in regulating redox levels and cell elongation processes. Three genes previously shown to modulate hydrogen peroxide levels were consistently expressed in domesticated and wild cotton species with long fibers, but expression was not detected by quantitative real time-PCR in wild species with short fibers. Hydrogen peroxide is important for cell elongation, but at high concentrations it becomes toxic, activating stress processes that may lead to early onset of secondary cell wall synthesis and the end of cell elongation. These observations suggest that the evolution of long spinnable fibers in cotton was accompanied by novel expression of genes assisting in the regulation of reactive oxygen species levels. Our data suggest a model for the evolutionary origin of a novel morphology through differential gene regulation causing prolongation of an ancestral developmental program
Nanolithography and manipulation of graphene using an atomic force microscope
We use an atomic force microscope (AFM) to manipulate graphene films on a
nanoscopic length scale. By means of local anodic oxidation with an AFM we are
able to structure isolating trenches into single-layer and few-layer graphene
flakes, opening the possibility of tabletop graphene based device fabrication.
Trench sizes of less than 30 nm in width are attainable with this technique.
Besides oxidation we also show the influence of mechanical peeling and
scratching with an AFM of few layer graphene sheets placed on different
substrates.Comment: 11 pages text, 5 figure
Dispersed Repetitive DNA Has Spread to New Genomes Since Polyploid Formation in Cotton
Polyploid formation has played a major role in the evolution of many plant and animal genomes; however, surprisingly little is known regarding the subsequent evolution of DNA sequences that become newly united in a common nucleus. Of particular interest is the repetitive DNA fraction, which accounts for most nuclear DNA in higher plants and animals and which can be remarkably different, even in closely related taxa. In one recently formed polyploid, cotton (Gossypium barbadense L.; AD genome), 83 non-cross-hybridizing DNA clones contain dispersed repeats that are estimated to comprise about 24% of the nuclear DNA. Among these, 64 (77%) are largely restricted to diploid taxa containing the larger A genome and collectively account for about half of the difference in DNA content between Old World (A) and New World (D) diploid ancestors of cultivated AD tetraploid cotton. In tetraploid cotton, FISH analysis showed that some A-genome dispersed repeats appear to have spread to D-genome chromosomes. Such spread may also account for the finding that one, and only one, D-genome diploid cotton, Gossypium gossypioides, contains moderate levels of (otherwise) A-genome-specific repeats in addition to normal levels of D-genome repeats. The discovery of A-genome repeats in G. gossypioides adds genome-wide support to a suggestion previously based on evidence from only a single genetic locus that this species may be either the closest living descendant of the New World cotton ancestor, or an adulterated relic of polyploid formation. Spread of dispersed repeats in the early stages of polyploid formation may provide a tag to identify diploid progenitors of a polyploid. Although most repetitive clones do not correspond to known DNA sequences, 4 correspond to known transposons, most contain internal subrepeats, and at least 12 (including 2 of the possible transposons) hybridize to mRNAs expressed at readily discernible levels in cotton seedlings, implicating transposition as one possible mechanism of spread. Integration of molecular, phylogenetic, and cytogenetic analysis of dispersed repetitive DNA may shed new light on evolution of other polyploid genomes, as well as providing valuable landmarks for many aspects of genome analysis
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