Search results for "Transmission rate"

showing 10 items of 13 documents

Tomato Brown Rugose Fruit Virus: Seed Transmission Rate and Efficacy of Different Seed Disinfection Treatments

2020

Tomato brown rugose fruit virus (ToBRFV) is a highly infectious virus, that is becoming a threat to tomato production worldwide. In this work we evaluated the localization of ToBRFV particles in tomato seeds, its seed transmission rate and efficacy of disinfection, and the effects of different thermal- and chemical-based treatments on ToBRFV-infected seeds&rsquo

0106 biological sciences0301 basic medicineCoatTransmission rateTomato brown rugose fruit virusPlant Scienceseed disinfectionBiology01 natural sciencesArticleEndosperm03 medical and health scienceschemistry.chemical_compoundlcsh:Botanyseed transmissionEcology Evolution Behavior and SystematicsInfectious virusEcologyfungifood and beveragesEmbryoToBRFVlcsh:QK1-989Horticulture030104 developmental biologychemistryGerminationSodium hypochlorite010606 plant biology & botanyPlants
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Statistical Explorations and Univariate Timeseries Analysis on COVID-19 Datasets to Understand the Trend of Disease Spreading and Death

2020

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0301 basic medicinetransmission ratepopulationSevere Acute Respiratory Syndromemedicine.disease_causelcsh:Chemical technologyBiochemistryRNNDisease OutbreaksAnalytical Chemistry0302 clinical medicinePandemiclcsh:TP1-1185030212 general & internal medicineInstrumentationVDP::Teknologi: 500::Informasjons- og kommunikasjonsteknologi: 550Coronaviruskeraseducation.field_of_studypublic healthartificial intelligenceAtomic and Molecular Physics and OpticsRegressionmachine learningGeographySevere acute respiratory syndrome-related coronavirusstatisticsMiddle East Respiratory Syndrome Coronaviruscommunity diseaseregressionCoronavirus InfectionsLSTMPneumonia ViralPopulationWorld Health OrganizationArticleBetacoronavirusspread factor03 medical and health sciencesCode (cryptography)medicineAnimalsHumansElectrical and Electronic EngineeringeducationPandemicsmeasurable sensor dataalgorithmSARS-CoV-2ICDUnivariatedeep learningOutbreakCOVID-19medicine.diseasehypothesis testpython030104 developmental biologycorrelationCatsMiddle East respiratory syndromeCattleDemographySensors
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Effectiveness of a project to prevent HIV vertical transmission in the Republic of Congo

2013

OBJECTIVES: To evaluate the effectiveness of a prevention programme against the vertical transmission of HIV in a resource-limited setting and to investigate variables associated with compliance. PATIENTS AND METHODS: The Kento-Mwana project (2005-2008) provided counselling, serological and biomolecular testing and prophylaxis/therapy to HIV-positive pregnant women and their children attending four antenatal clinics in Pointe Noire, Republic of Congo. Expected and actual rates of vertical transmission of HIV were compared. Univariate and multivariate analyses were performed in order to identify variables associated with non-compliance. RESULTS: The observed transmission rate in the group wh…

MaleInfectious Disease TransmissionPMTCTHuman immunodeficiency virus (HIV)HIV Infectionsmedicine.disease_causeSettore MED/42 - Igiene Generale E Applicatalaw.inventionlawPregnancyVerticalPharmacology (medical)Prospective StudiesPregnancy Complications InfectiousProspective cohort studyAttrition; Drop-out; Lost to follow-up; Mother-to-child transmission; PMTCT; Congo; Female; HIV Infections; Humans; Infant; Infant Newborn; Infectious Disease Transmission Vertical; Male; Patient Acceptance of Health Care; Patient Compliance; Pregnancy; Pregnancy Complications Infectious; Prospective Studies; Health Services Research; Pharmacology; Pharmacology (medical); Infectious DiseasesInfectiousdrop-outTransmission (mechanics)Infectious DiseasesCongoFemaleHealth Services ResearchMicrobiology (medical)attritionHIV prevention; vertical transmission; republic of CongoTransmission rateHIV preventionTarget populationPrenatal caremedicineHumansLost to follow-upPharmacologylost to follow-upPregnancybusiness.industryInfant Newbornmother-to-child transmissionInfantrepublic of CongoPatient Acceptance of Health Caremedicine.diseaseNewbornInfectious Disease Transmission VerticalPregnancy ComplicationsImmunologyPatient Compliancevertical transmissionbusinessDemography
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Microwave phase shifter based on fibre Bragg grating

1998

A variable delay line is presented for phased array antennas based on a fibre Bragg grating which has a uniform period and operates at constant optical wavelength. The Bragg wavelength of a localised part of the fibre grating is modified by straining the fibre, the optical carrier is reflected by the strained part of the grating and the time delay of the microwave modulating signal is determined by the position where the strain has been applied. In this initial experiment time delay variations up to 330 ps in the frequency range 1 – 14 GHz have been achieved.

Materials sciencegenetic structuresPhased arraybusiness.industryPhysics::OpticsGratingÒpticalaw.inventionWavelengthOpticsFiber Bragg gratingOptical Carrier transmission rateslawBlazed gratingAntenes (Electrònica)sense organsElectrical and Electronic EngineeringbusinessPhase shift moduleMicrowavepsychological phenomena and processes
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Three-Dimensional Microstructural Properties of Nanofibrillated Cellulose Films

2014

Abstract: Nanofibrillated cellulose (NFC) films have potential as oxygen barriers for, e.g., food packaging applications, but their use is limited by their hygroscopic characteristics. The three-dimensional microstructure of NFC films made of Pinus radiata (Radiata Pine) kraft pulp fibres has been assessed in this study, considering the structural development as a function of relative humidity (RH). The surface roughness, micro-porosity, thickness and their correlations were analyzed using X-ray microtomography (X–μCT) and computerized image analysis. The results are compared to those from scanning electron microscopy and laser profilometry. Based on a series of films having varying amounts…

OTRMaterials scienceScanning electron microscopeSurface PropertiesNFCNanofiberstomographyCatalysisArticlenanofibrillated cellulose; NFC; oxygen transmission rate; OTR; tomography; humiditylcsh:ChemistryInorganic Chemistrychemistry.chemical_compoundOxygen transmission ratetomografiaSurface roughnessRelative humidityPhysical and Theoretical ChemistryCelluloseComposite materialoxygen transmission ratePorosityCelluloselcsh:QH301-705.5Molecular BiologySpectroscopyta114Organic ChemistryhumidityHumidityGeneral MedicineX-Ray MicrotomographyMicrostructurePinusComputer Science ApplicationsOxygenlcsh:Biology (General)lcsh:QD1-999chemistryMicroscopy Electron Scanningnanofibrillated cellulosePorosity
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Electronic tuning of delay lines based on chirped fiber gratings for phased arrays powered by a single optical carrier

2004

We propose a variable delay line for phased arrays antennas based on a chirped fiber grating. The line operates with an optical carrier at constant wavelength and the time delay of the radiofrequency modulating signal is modified stretching the grating with a piezoelectric translator, the grating response can be tuned at a speed of 0.68 nm/ms.

Optical fiberMaterials sciencePhased arraybusiness.industryPhysics::OpticsGratingSignalAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialslaw.inventionWavelengthOpticsFiber Bragg gratinglawOptical Carrier transmission ratesBlazed gratingPhysics::Atomic PhysicsElectrical and Electronic EngineeringPhysical and Theoretical ChemistrybusinessOptics Communications
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Tunable microwave photonic filter based on chirped fiber gratings working with a single optical carrier at constant wavelength

2007

This paper presents a tunable transversal filter working with a single optical carrier at constant wavelength. The filter consists of a set of chirped gratings whose time delay is tuned with respect to the emission wavelength of a fiber laser by a piezoelectric actuator; extra lengths of fiber are inserted in the filter arms in order to avoid interferences between signals reflected in different gratings. Two and three taps filters are experimentally demonstrated, the filters transfer function is electronically tuned within the free spectral range.

Optical fiberMaterials sciencebusiness.industryPhysics::OpticsLaserAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialslaw.inventionOpticslawFilter (video)Optical Carrier transmission ratesFiber laserElectrical and Electronic EngineeringPhysical and Theoretical ChemistryPhotonicsbusinessDiffraction gratingFree spectral rangeOptics Communications
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Optical demultiplexing of millimeter-wave subcarriers for wireless channel distribution employing dual wavelength FBGs

2007

An optical mm-wave demultiplexer is presented. Double sideband modulation with suppressed optical carrier and filtering properties of dual overwritten fiber Bragg gratings are the fundamentals for optical demultiplexing of mm-wave radio-on-fiber signals: using a single optical carrier, Millimeter-wave signals of 20 and 40 GHz frequencies carrying independent data are created, transmitted over fiber, demultiplexed and wireless distributed to be detected and data recovered in a mobile unit. Double sideband modulation with suppressed optical carrier yields no power penalty due to chromatic dispersion, while the filtering properties of the dual overwritten fiber Bragg gratings allow less than −…

PhysicsDemultiplexerbusiness.industryOptical communicationPhysics::OpticsAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsOpticsFiber Bragg gratingOptical Carrier transmission ratesWavelength-division multiplexingDouble-sideband suppressed-carrier transmissionElectrical and Electronic EngineeringPhysical and Theoretical ChemistryPlastic optical fiberbusinessOptical aberrationOptics Communications
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Evaluation of all-optical demultiplexing in millimeter-wave subcarrier-system for wireless communication

2006

In this paper, a scheme for multiplexing millimeter-wave carriers on a single optical carrier and using an all-optical millimeter-wave demultiplexer is presented. The optical demultiplexing of radio-over-fiber signals is based on dual sideband modulation with suppressed optical carrier combined with the filtering properties of dual over-written fiber Bragg gratings. The performance of the system is investigated using a single optical carrier and independent data modulated millimeter-wave signals at 20 and 40 GHz. The signals are transmitted over optical fiber, demultiplexed and wirelessly distributed to a mobile unit. It is found that performance of the demultiplexing using fiber Bragg grat…

PhysicsOptical fiberSidebandbusiness.industryPhysics::OpticsMultiplexingSubcarrierAmplitude-shift keyinglaw.inventionOpticsFiber Bragg gratinglawOptical Carrier transmission ratesbusinessQuadrature amplitude modulation2006 International Topical Meeting on Microwave Photonics
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Model Analysis of Hydrometeor Scattering Effects on Free Space Near-Infrared Links

2012

A promising technology for peer-to-peer connections and urban area networks is represented by wireless communications through free space using optical carrier (Free Space Optics, FSO). This technology ensures high data rates, with relatively low error rates, low power consumption and inherent security. Nevertheless FSO links are quite sensitive to atmospheric condition. Fog droplets, but also raindrops and snowflakes, may introduce severe path attenuation which drastically reduces the channel availability. A parametric model to simulate droplets scattering effects over the FSO link in terms of extinction coefficient, albedo factor and asymmetry coefficient as function of the particle water …

PhysicsScatteringbusiness.industrySettore ING-INF/03 - TelecomunicazioniAttenuationOptical communicationSettore ING-INF/02 - Campi ElettromagneticiMolar absorptivityOpticsfree space optics; water contents; atmospheric data and optical modellingfree space optics atmospheric data and optical modelling water contents.atmospheric data and optical modellingOptical Carrier transmission ratesParametric modelwater contentsfree space opticsSnowflakebusinessFree-space optical communication
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