315 research outputs found

    Market capture by 30/20 GHz satellite systems. Volume 1: Executive summary

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    Demand for 30/20 GHz satellite systems over the next two decades is projected. Topics include a profile of the communications market, switched, dedicated, and packet transmission modes, deferred and real-time traffic, quality and reliability considerations, the capacity of competing transmission media, and scenarios for the growth and development of 30/20 GHz satellite communications

    Customer premises services market demand assessment 1980 - 2000. Volume 1: Executive summary

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    Estimates of market demand for domestic civilian telecommunications services for the years 1980 to 2000 are provided. Overall demand, demand or satellite services, demand for satellite delivered Customer Premises Service (CPS), and demand for 30/20 GHz Customer Premises Services are covered. Emphasis is placed on the CPS market and demand is segmented by market, by service, by user class and by geographic region. Prices for competing services are discussed and the distribution of traffic with respect to distance is estimated. A nationwide traffic distribution model for CPS in terms of demand for CPS traffic and earth stations for each of the major SMSAs in the United States are provided

    Market capture by 30/20 GHz satellite systems, volume 2

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    Results of a telecommunications demand study are presented. Forecasts of demand for 30/20 GHz satellite systems, and the expected build up of traffic on these systems are given as a function of time for each of several operational scenarios

    Relationship among growth curve, nutrient consumption and genetic transformation efficiency of 'Albariño' (Vitis vinifera) cell suspensions

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    Embryogenic cell suspensions of grapevine (Vitis sp.) have been proposed as the best target to approach genetic transformation challenges. However, optimal phase and growth period of cell suspensions for successful gene transfer have not been investigated. Here, a step by step protocol to initiate and establish cell suspensions of 'Albariño' (V. vinifera) in only 4 weeks is presented. Growth kinetics, cell viability and nutrient consumption (phosphates and nitrates) as well as the number of transient transgenic events (using the uidA reporter gene) were studied in 'Albariño' cell suspensions grown for an 18-days period. Based on biomass growth, the exponential phase of cell suspensions was reached between days 3 to 6. Nutrient uptake results point to the exhaustion of phosphate in the culture medium at day 6. Moreover, the highest number of transgenic events after biolistic bombardment was obtained from cell suspensions grown for 6 days (4032 ± 695 blue spots), compared to 12 and 18 days of continuous culture. Plant regeneration percentage varied depending on the age of the culture and the selected embryo type. In conclusion, this paper shows for the first time the relationship between growth curve and nutrient consumption of embryogenic cell suspension with efficiency in genetic transformation and plant regeneration of grapevine

    Convergence to stable laws for multidimensional stochastic recursions: the case of regular matrices

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    Given a sequence (Mn,Qn)n1(M_{n},Q_{n})_{n\ge 1} of i.i.d.\ random variables with generic copy (M,Q)GL(d,R)×Rd(M,Q) \in GL(d, \R) \times \R^d, we consider the random difference equation (RDE) Rn=MnRn1+Qn, R_{n}=M_{n}R_{n-1}+Q_{n}, n1n\ge 1, and assume the existence of κ>0\kappa >0 such that \lim_{n \to \infty}(\E{\norm{M_1 ... M_n}^\kappa})^{\frac{1}{n}} = 1 . We prove, under suitable assumptions, that the sequence Sn=R1+...+RnS_n = R_1 + ... + R_n, appropriately normalized, converges in law to a multidimensional stable distribution with index κ\kappa. As a by-product, we show that the unique stationary solution RR of the RDE is regularly varying with index κ\kappa, and give a precise description of its tail measure. This extends the prior work http://arxiv.org/abs/1009.1728v3 .Comment: 15 page

    Financial Transaction Tax: Small is Beautiful

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    The case for taxing financial transactions merely to raise more revenues from the financial sector is not particularly strong. Better alternatives to tax the financial sector are likely to be available. However, a tax on financial transactions could be justified in order to limit socially undesirable transactions when more direct means of doing so are unavailable for political or practical reasons. Some financial transactions are indeed likely to do more harm than good, especially when they contribute to the systemic risk of the financial system. However, such a financial transaction tax should be very small, much smaller than the negative externalities in question, because it is a blunt instrument that also drives out socially useful transactions. There is a case for taxing over-the-counter derivative transactions at a somewhat higher rate than exchange-based derivative transactions. More targeted remedies to drive out socially undesirable transactions should be sought in parallel, which would allow, after their implementation, to reduce or even phase out financialtransaction taxes

    The materiality of the intangible: Literary metaphor in multimodal texts

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    Based on a larger practice-based research project in digital writing, this article examines how the materiality of digital media contributes to a layered metaphor that delivers meaning, reflects on the cognitive processes (the writer’s and the reader’s) of navigation and generates a dynamic narrative structure through multimodality, unnatural narration and user interaction. Many writers and artists engage with their chosen medium through an instinctive understanding of the materials at hand, gained through experience; the explicit study of a medium’s materiality is not always required for artistic success, however, that may be judged. This article offers insights into the creative process of creating digital, multimodal fiction, based on a practice-based research project designed to explore the effects of digital media on author and text, and argues that digital media have a significant effect on the outcome of the artefact itself. Awareness of these effects, their variations according to hardware and software, and the affordances of these various materials offer the digital writer greater insight and capability to craft his/her texts for the desired metaphorical meaning

    Absence of Dystrophin Related Protein-2 disrupts Cajal bands in a patient with Charcot-Marie-Tooth disease

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    Using exome sequencing in an individual with Charcot-Marie-Tooth disease (CMT) we have identified a mutation in the X-linked dystrophin-related protein 2 (DRP2) gene. A 60-year-old gentleman presented to our clinic and underwent clinical, electrophysiological and skin biopsy studies. The patient had clinical features of a length dependent sensorimotor neuropathy with an age of onset of 50 years. Neurophysiology revealed prolonged latencies with intermediate conduction velocities but no conduction block or temporal dispersion. A panel of 23 disease causing genes was sequenced and ultimately was uninformative. Whole exome sequencing revealed a stop mutation in DRP2, c.805C>T (Q269*). DRP2 interacts with periaxin and dystroglycan to form the periaxin-DRP2-dystroglycan complex which plays a role in the maintenance of the well-characterized Cajal bands of myelinating Schwann cells. Skin biopsies from our patient revealed a lack of DRP2 in myelinated dermal nerves by immunofluorescence. Furthermore electron microscopy failed to identify Cajal bands in the patient's dermal myelinated axons in keeping with ultrastructural pathology seen in the Drp2 knockout mouse. Both the electrophysiologic and dermal nerve twig pathology support the interpretation that this patient's DRP2 mutation causes characteristic morphological abnormalities recapitulating the Drp2 knockout model and potentially represents a novel genetic cause of CMT

    An application of kernel methods to variety identification based on SSR markers genetic fingerprinting

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    <p>Abstract</p> <p>Background</p> <p>In crop production systems, genetic markers are increasingly used to distinguish individuals within a larger population based on their genetic make-up. Supervised approaches cannot be applied directly to genotyping data due to the specific nature of those data which are neither continuous, nor nominal, nor ordinal but only partially ordered. Therefore, a strategy is needed to encode the polymorphism between samples such that known supervised approaches can be applied. Moreover, finding a minimal set of molecular markers that have optimal ability to discriminate, for example, between given groups of varieties, is important as the genotyping process can be costly in terms of laboratory consumables, labor, and time. This feature selection problem also needs special care due to the specific nature of the data used.</p> <p>Results</p> <p>An approach encoding SSR polymorphisms in a positive definite kernel is presented, which then allows the usage of any kernel supervised method. The polymorphism between the samples is encoded through the Nei-Li genetic distance, which is shown to define a positive definite kernel between the genotyped samples. Additionally, a greedy feature selection algorithm for selecting SSR marker kits is presented to build economical and efficient prediction models for discrimination. The algorithm is a filter method and outperforms other filter methods adapted to this setting. When combined with kernel linear discriminant analysis or kernel principal component analysis followed by linear discriminant analysis, the approach leads to very satisfactory prediction models.</p> <p>Conclusions</p> <p>The main advantage of the approach is to benefit from a flexible way to encode polymorphisms in a kernel and when combined with a feature selection algorithm resulting in a few specific markers, it leads to accurate and economical identification models based on SSR genotyping.</p
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