495 research outputs found

    Non-Binary Message-Passing Algorithms for Magnetic Channels with Data-Dependent Noise

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    The paper proposes an implementation of the message passing algorithm adapted to iterative channel detection. The algorithm uses soft messages associated to non binary symbols in order to cancel cycles in the equivalent Tanner graphs, achieving optimal performance after a low number of iterations. This architecture, suited to very fast channel detectors, is applied to magnetic recording channels and adapted to the non stationary nature of the magnetic media noise

    The nature and evolution of Nova Cygni 2006

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    AIMS: Nova Cyg 2006 has been intensively observed throughout its full outburst. We investigate the energetics and evolution of the central source and of the expanding ejecta, their chemical abundances and ionization structure, and the formation of dust. METHOD: We recorded low, medium, and/or high-resolution spectra (calibrated into accurate absolute fluxes) on 39 nights, along with 2353 photometric UBVRcIc measures on 313 nights, and complemented them with IR data from the literature. RESULTS: The nova displayed initially the normal photometric and spectroscopic evolution of a fast nova of the FeII-type. Pre-maximum, principal, diffuse-enhanced, and Orion absorption systems developed in a normal way. After the initial outburst, the nova progressively slowed its fading pace until the decline reversed and a second maximum was reached (eight months later), accompanied by large spectroscopic changes. Following the rapid decline from second maximum, the nova finally entered the nebular phase and formed optically thin dust. We computed the amount of formed dust and performed a photo-ionization analysis of the emission-line spectrum during the nebular phase, which showed a strong enrichment of the ejecta in nitrogen and oxygen, and none in neon, in agreement with theoretical predictions for the estimated 1.0 Msun white dwarf in Nova Cyg 2006. The similarities with the poorly investigated V1493 Nova Aql 1999a are discussed.Comment: in press in Astronomy and Astrophysic

    Use of water in the Iberoamérican dry lands: hydro-environmental and socioeconomic efficiency indicators

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    Uso del agua en tierras secas de Iberoamérica: indicadores de eficiencia hidro-ambiental y socio-económica. Las tierras secas comprenden una superficie sustancial de Iberoamérica (25% de América Latina y el Caribe, o más de la mitad del estado español). En este contexto, Brasil posee una porción significativa de los recursos hídricos superficiales y subterráneos. Sin embargo, en su territorio se encuentran áreas semi-áridas, con extrema escasez hídrica, que comprenden 1300 municipios (cerca del 25% del total de municipios del país), distribuidos en 9 estados, en los que viven más de 22,5 millones de habitantes. Estos se encuentran afectados directa o indirectamente por una situación de severa escasez de recursos hídricos agravada por cambios climáticos, consecuencia del calentamiento global. Resulta importante conocer el acervo de tecnologías tradicionales y no tradicionales para captar, almacenar, y utilizar el agua, adaptadas a las diferentes situaciones socio-económicas e hidro-ambientales, así como indicadores del uso eficiente del agua, validados y homologados como herramienta estratégica de gestión en políticas y programas de seguridad hídrica. Este trabajo tiene como objetivo conocer el estado de nuestro conocimiento sobre dichos indicadores y discutir el caso del semi-árido brasileño en el contexto de las tierras secas de Iberoamérica, y del Plan Nacional de Recursos Hídricos del Estado de Bahía.The dry lands cover  expressive  surface  of  Iberoamerican  (25%  of  Latin  American  and  Caribbean  and  more  than  half  of  the  Spanish  territory).  In  this context, Brazil is a country that possesses significant volume of the world superficial and underground water resources. However, more than 1300 municipal districts (about 25% of the total of municipal districts of the country), distributed in 9 states are directly or indirectly affected  by  extreme  shortage  of  water  resources  which  has  been  worsened  by  the  climatic  changes,  as  a  consequence  of  the  global warming.  More  than  22.5  million  inhabitants  live  in  the  semi-arid areas of Brazil. It is important to scrutiny all traditional and not traditional technologies  for  reception,  storage  and  use  of  the  water,  adapted  for  different  socioeconomic  and  hydro-environmental  situations  and approve and validate indicators of water use efficiency, as a management strategic tool for water security politics and programs. This work aimed to understand the state of the art on indicators and to discuss the Brazilian case of the semi-arid in the context of the Iberoamerican dry lands, based on the National Plan of Water Resources and on the State of Bahia Plan for Water Resource Management.Fil: Carneiro, A. P.. Universidad Politécnica de Catalunya; EspañaFil: da Silva, H. P.. Universidade Federal da Bahia; BrasilFil: Abraham, Elena Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Morató, J.. No especifíca;Fil: Subirana, A.. Universidad Politécnica de Catalunya; EspañaFil: Tomasoni, M.. Universidade Federal da Bahia; Brasi

    Relationship between the prevalence of Dibothriocephalus latus(Cestoda: Diphyllobothriidea) and the load of Escherichia coli: New findings in a neglected fish-borne parasitic zoonosis

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    The sub-Alpine lakes of Switzerland, Italy and France have long been reported as an endemic area of diphyllobothriosis, a parasitic zoonosis aused by Dibothriocephalus latus. With this study, we explored the hypothesis for a relationship between the prevalence of D. latus in Perca fluviatilis and the Escherichia coli load in lake water. To do this, we identified eleven sampling sites in three areas (north, centre and south) of Lake Iseo (north Italy) to determine E. coli load and the prevalence of D. latus in P. fluviatilis. Prevalence and 95% confidence interval (CI) of D. latus infestation ranged from 0% (95% CI: 0.71–0.0) in Sarnico (southern area) to 20% (95% CI: 33.0–11.2) in Pisogne (northern area). There were significant differences in prevalence be-tween the sites (χ2= 31.12; p- value= .0006) and in E. coli load (Kruskal–Wallis test; p- value= .0005). There was decreasing gradient of E. coli load and prevalence of D. latus infestation from north to south. A significant positive correlation (r= .881; p- value= .003) was found between E. coli load and prevalence of D. latus. Also, linear regression showed a significant relationship between E. coli load and prevalence of infestation (R2= .775). Our findings offer an explanation for the link between E. coliload in water and D. latus prevalence. The potential factors in this link are the ef-ficiency of the local wastewater treatment plant, the bathymetric profile of the lake and the life cycle of D. latus, which is mainly affected by light and water temperature.KEYWORDSItaly, Lake Iseo, Perca fluviatilis, prevalence of infestation, wastewater treatment plant, the bathymetric profile of the lake and the life cycle of D. latus, which is mainly affected by light and water temperature

    Miscarriage following dengue virus 3 infection in the first six weeks of pregnancy of a dengue virus-naive traveller returning from Bali to Italy, April 2016

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    We report miscarriage following dengue virus (DENV)-3 infection in a pregnant woman returning from Bali to Italy in April 2016. On her arrival, the woman had fever, rash, asthenia and headache. DENV RNA was detected in plasma and urine samples collected the following day. Six days after symptom onset, she had a miscarriage. DENV RNA was detected in fetal material, but in utero fetal infection cannot be demonstrated due to possible contamination by maternal blood

    EUS-guided drainage using lumen apposing metal stent and percutaneous endoscopic necrosectomy as dual approach for the management of complex walled-off necrosis: a case report and a review of the literature

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    Background: Endoscopic ultrasound-guided drainage is suggested as the first approach in the management of symptomatic and complex walled-off pancreatic necrosis. Dual approach with percutaneous drainage could be the best choice when the necrosis is deep extended till the pelvic paracolic gutter; however, the available catheter could not be large enough to drain solid necrosis neither to perform necrosectomy, entailing a higher need for surgery. Therefore, percutaneous endoscopic necrosectomy through a large bore percutaneous self-expandable metal stent has been proposed. Case presentation: In this study, we present the case of a 61-year-old man admitted to our hospital with a history of sepsis and persistent multiorgan failure secondary to walled-off pancreatic necrosis due to acute necrotizing pancreatitis. Firstly, the patient underwent transgastric endoscopic ultrasound-guided drainage using a lumen-apposing metal stent and three sessions of direct endoscopic necrosectomy. Because of recurrence of multiorgan failure and the presence of the necrosis deeper to the pelvic paracolic gutter at computed tomography scan, we decided to perform percutaneous endoscopic necrosectomy using an esophageal self-expandable metal stent. After four sessions of necrosectomy, the collection was resolved without complications. Therefore, we perform a revision of the literature, in order to provide the state-of-art on this technique. The available data are, to date, derived by case reports and case series, which showed high rates both of technical and clinical success. However, a not negligible rate of adverse events has been reported, mainly represented by fistulas and abdominal pain. Conclusion: Dual approach, using lumen apposing metal stent and percutaneous self-expandable metal stent, is a compelling option of treatment for patients affected by symptomatic, complex walled-off pancreatic necrosis, allowing to directly remove large amounts of necrosis avoiding surgery. Percutaneous endoscopic necrosectomy seems a promising technique that could be part of the step-up-approach, before emergency surgery. However, to date, it should be reserved in referral centers, where a multidisciplinary team is disposable

    A Quantitative Estimate of the Expected Shortening of the Median Isolation Period of Patients With COVID-19 After the Adoption of a Symptom-Based Strategy

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    A long period of isolation was observed in patients hospitalized for COVID-19 in Milan over March-September 2020 (45; IQR: 37–54 days). A significantly shorter period would have been observed by the application of May-WHO (22, IQR: 17–30 days, P < 0.001) and October-Italian (26, IQR: 21–34 days, P < 0.001) Guidelines. The adoption of the new symptom-based criteria is likely to lead to a significant reduction in the length of the isolation period with potential social, economic and psychological benefits, particularly in the younger population with mild/moderate disease and no comorbidities. In our opinion, the release from isolation after 21 days from symptoms onset, even without a PCR diagnostic test, in most cases seems the most adequate strategy that could balance precautions to prevent SARS CoV-2 transmission and unnecessary prolonged isolation or overuse of diagnostic testing

    The unusual isolation of carnobacteria in eyes of healthy salmonids in high‑mountain lakes

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    Carnobacteria are common bacteria in cold and temperate environments; they are also reported during fsh mortality events. In a previous study, carnobacteria were isolated from the eyes of healthy wild salmonids from a high-mountain lake. To better understand these fndings, salmonids were captured from three high-mountain lakes (Lower and Upper Balma Lake, Rouen Lake; northwest Italy) during August 2019 and subjected to bacteriological and histological examination. Although all were healthy, 8.7% (Lower Balma Lake), 24% (Upper Balma Lake), and 32.6% (Rouen Lake) were positive for carnobacteria colonization of the eyes. A Trojan-horse efect was hypothesized to explain carnobacteria isolation in the eye. This immune-escaping macrophage-mediated mechanism has been identifed in other Gram-positive bacteria. Biochemical, molecular, and phylogenetic analysis were carried out on isolated bacteria (Carnobacterium maltaromaticum and C. divergens). Based on previous references for carnobacteria isolated from fsh, C. maltaromaticum strains were tested for the pisA precursor gene of the bacteriocin piscicolin 126. Carnobacterium maltaromaticum strains were found to display genotypic heterogeneity and a low percentage of pisA positive amplifcation. Features of geomorphology, geographic isolation, and microbiota common to the three lakes are thought to be possibly related to our fndings. Moreover, terrestrial insects collected from the lake shoreline and the stomach contents were screened for the presence of carnobacteria. The salmonids in these high-mountain environments feed mainly on terrestrial insects, which are considered possible vectors for carnobacteria that might catabolize the exoskeleton chitin. All insects tested negative for carnobacteria, but as a small number of samples were analyzed, their role as possible vectors of infection cannot be excluded. Further studies are needed to corroborate our research hypothesis
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