471 research outputs found

    Classificação de áreas de café em Minas Gerais por meio do novo algoritmo QMAS em imagem espectral Geoeye-1.

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    Diante do grande desafio que é classificar imagens de sensoriamento remoto de café, o objetivo deste trabalho foi aplicar o novo algoritmo QMAS para classificar áreas de café comparando os resultados com o método tradicional de Classificação Supervisionada MAXVER, em imagens Geoeye-1. Os resultados indicam que o algoritmo QMAS obteve mais êxito na classificação das áreas de café do que o MAXVER, configurando-se em uma alternativa viável a classificação de imagens de satélite.SBSR 2011

    Detector decoy quantum key distribution

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    Photon number resolving detectors can enhance the performance of many practical quantum cryptographic setups. In this paper, we employ a simple method to estimate the statistics provided by such a photon number resolving detector using only a threshold detector together with a variable attenuator. This idea is similar in spirit to that of the decoy state technique, and is specially suited for those scenarios where only a few parameters of the photon number statistics of the incoming signals have to be estimated. As an illustration of the potential applicability of the method in quantum communication protocols, we use it to prove security of an entanglement based quantum key distribution scheme with an untrusted source without the need of a squash model and by solely using this extra idea. In this sense, this detector decoy method can be seen as a different conceptual approach to adapt a single photon security proof to its physical, full optical implementation. We show that in this scenario the legitimate users can now even discard the double click events from the raw key data without compromising the security of the scheme, and we present simulations on the performance of the BB84 and the 6-state quantum key distribution protocols.Comment: 27 pages, 7 figure

    DISTRIBUZIONE STORICA E ATTUALE DELLE SPECIE DEL GENERE JUNIPERUS (Cupressaceae) IN SICILIA

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    The distribution of the three juniper species occurring in Sicily, namely Juniperus communis, J. oxycedrus subsp. macrocarpa and J. turbinata, was updated. The setup of a critical inventory of the vernacular plant names referring to these species has also allowed to carry out a systematic search for place names reported on ancient and recent cartographic documents and to identify other coastal juniper populations neglected by botanists or certainly extinct. This paper points out the probable extinction of several stands of J. oxycedrus subsp. macrocarpa and J. turbinata, reported in the literature or documented by herbarium specimens. Sporadic references made in the past two centuries to the presence of J. sabina L. in Sicily and of J. communis on the Nebrodi and Erei Mountains have not been confirmed by the surveys carried out over the past decades. Finally, several occurrence and demographic data are presented concerning several unpublished or poorly known nuclei of J. oxycedrus subsp. macrocarpa and J. turbinata; some of them have been recently discovered, such as the one near Rasocolmo on the northeastern coast of Sicily, while others, documented by herbarium specimens or already reported in old publications, had been neglected by the most recent botanical literature devoted to these conifers. Numerous field surveys enabled the authors to provide updated and detailed information on the current distribution of J. communis on Mount Etna and of J. oxycedrus subsp. macrocarpa and J. turbinata in the coastal and hillside areas of the provinces of Caltanissetta and Ragusa, previously available information on these areas being generic, dated and fragmentary. Moreover, some populations of J. oxycedrus subsp. macrocarpa found along the sandy beaches of the Agrigento and Ragusa areas probably derive from the widespread use of this species in the reforestations carried out during the last century on the dune systems once widespread along the coast of the Strait of Sicily. All the traditional local uses of the different juniper species are reported, too. Focusing on the Sicilian territory, thanks to its interdisciplinary approach and the effort to provide a spatial-temporal perspective as complete as possible, this work may represent a replicable model for conducting similar research, aimed at reconstructing the past and potential distribution of other forest species, in order to better direct future reforestation interventions and the restoration of native vegetation on a regional scale

    Irs2 Silencing Increases Apoptosis And Potentiates The Effects Of Ruxolitinib In Jak2v617f-positive Myeloproliferative Neoplasms.

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    The recurrent V617F mutation in JAK2 (JAK2V617F) has emerged as the primary contributor to the pathogenesis of myeloproliferative neoplasms (MPN). However, the lack of complete response in most patients treated with the JAK1/2 inhibitor, ruxolitinib, indicates the need for identifying pathways that cooperate with JAK2. Activated JAK2 was found to be associated with the insulin receptor substrate 2 (IRS2) in non-hematological cells. We identified JAK2/IRS2 binding in JAK2V617F HEL cells, but not in the JAK2WT U937 cell line. In HEL cells, IRS2 silencing decreased STAT5 phosphorylation, reduced cell viability and increased apoptosis; these effects were enhanced when IRS2 silencing was combined with ruxolitinib. In U937 cells, IRS2 silencing neither reduced cell viability nor induced apoptosis. IRS1/2 pharmacological inhibition in primary MPN samples reduced cell viability in JAK2V617F-positive but not JAK2WT specimens; combination with ruxolitinib had additive effects. IRS2 expression was significantly higher in CD34+ cells from essential thrombocythemia patients compared to healthy donors, and in JAK2V617F MPN patients when compared to JAK2WT. Our data indicate that IRS2 is a binding partner of JAK2V617F in MPN. IRS2 contributes to increased cell viability and reduced apoptosis in JAK2-mutated cells. Combined pharmacological inhibition of IRS2 and JAK2 may have a potential clinical application in MPN.

    Optical and mid-infrared line emission in nearby Seyfert galaxies

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    Line ratio diagnostics provide valuable clues on the source of ionizing radiation in galaxies with intense black hole accretion and starbursting events, such as local Seyfert or galaxies at the peak of the star formation history. We aim to provide a reference joint optical and mid-IR analysis for studying AGN identification via line ratios and testing predictions from photoionization models. We obtained homogenous optical spectra with the Southern Africa Large Telescope for 42 Seyfert galaxies with Spitzer/IRS spectroscopy and X-ray to mid-IR multiband data available. After confirming the power of the main optical ([OIII]) and mid-IR ([NeV], [OIV], [NeIII]) emission lines in tracing AGN activity, we explore diagrams based on ratios of optical and mid-IR lines by exploiting photoionization models of different ionizing sources (AGN, star formation and shocks). We find that pure AGN photoionization models are good at reproducing observations of Seyfert galaxies with an AGN fractional contribution to the mid-IR (5-40 micron) emission larger than 50 per cent. For targets with a lower AGN contribution these same models do not fully reproduce the observed mid-IR line ratios. Mid-IR ratios like [NeV]/[NeII], [OIV]/[NeII] and [NeIII]/[NeII] show a dependence on the AGN fractional contribution to the mid-IR unlike optical line ratios. An additional source of ionization, either from star formation or radiative shocks, can help explain the observations in the mid-IR. Among combinations of optical and mid-IR diagnostics in line ratio diagrams, only those involving the [OI]/Halpha ratio are promising diagnostics for simultaneously unraveling the relative role of AGN, star formation and, shocks. A proper identification of the dominant ionizing source would require the exploitation of analysis tools based on advanced statistical techniques as well as spatially resolved data.Comment: 31 pages, 15 figures, 2 tables. Accepted for publication in A&

    Ceramic on ceramic bearing fractures in total hip arthroplasty : an analysis of data from the national joint registry

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    Aims: Ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry (NJR). Patients and Methods: We analysed data on 111,681 primary CoC THA’s and 182 linked revisions for bearing fracture recorded in NJR. We used implant codes to identify ceramic bearing composition and generated Kaplan-Meier estimates for implant survivorship. Logistic regression analyses were performed for implant size and patient specific variables to determine any associated risks for revision. Results: 99.8% of bearings were CeramTec Biolox® products. Revisions for fracture were linked to 7 of 79,442 (0.009%) Biolox® Delta heads, 38 of 31,982 (0.119%) Biolox® Forte heads, 101 of 80,170 (0.126%) Biolox® Delta liners and 35 of 31,258 (0.112%) Biolox® Forte liners. Regression analysis of implant size revealed smaller heads had significantly higher odds of fracture (χ2=68.0, p<0.0001). The highest fracture risk were observed in the 28mm Biolox® Forte subgroup (0.382%). There were no fractures in the 40mm head group for either ceramic type. Liner thickness was not predictive of fracture (p=0.67). BMI was independently associated with revision for both head fractures (OR 1.09 per unit increase, p=0.031) and liner fractures (OR 1.06 per unit increase, p=0.006). Conclusions: We report the largest study of CoC bearing fractures to date. The risk of revision for CoC bearing fracture is very low, however previous studies have underestimated this risk. There is good evidence that the latest generation of ceramic has greatly reduced the odds of head fracture but not of liner fracture. Small head size and high patient BMI are associated with an increased risk of ceramic bearing fracture
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