Importância da origem do material de propagação na qualidade da muda de videira.

bitstream/CNPUV/8128/1/cir050.pdfDisponível também no formato online

Doenças de uva.

São conhecidas na videira (Vitis spp.) dezenas de doenças consideradas de origem viral. A videira, por ser propagada vegetativamente, facilita a disseminação destes patógenos e favorece o aparecimento de doenças complexas, pelo acúmulo de diferentes vírus numa mesma planta

Radii of 88 M subdwarfs and updated radius relations for low-metallicity M-dwarf stars

M subdwarfs are low-metallicity M dwarfs that typically inhabit the halo population of the Galaxy. Metallicity controls the opacity of stellar atmospheres; in metal-poor stars, hydrostatic equilibrium is reached at a smaller radius, leading to smaller radii for a given effective temperature. We compile a sample of 88 stars that span spectral classes K7 to M6 and include stars with metallicity classes from solar-metallicity dwarf stars to the lowest metallicity ultra subdwarfs to test how metallicity changes the stellar radius. We fit models to Palomar Double Spectrograph (DBSP) optical spectra to derive effective temperatures (T_ eff) and we measure bolometric luminosities (L_ bol) by combining broad wavelength-coverage photometry with Gaia parallaxes. Radii are then computed by combining the T_ eff and L_ bol using the Stefan–Boltzman law. We find that for a given temperature, ultra subdwarfs can be as much as five times smaller than their solar-metallicity counterparts. We present color-radius and color-surface brightness relations that extend down to [Fe/H] of −2.0 dex, in order to aid the radius determination of M subdwarfs, which will be especially important for the WFIRST exoplanetary microlensing survey.Published versio

The Low Velocity Wind from the Circumstellar Matter Around the B9V Star sigma Herculis

We have obtained FUSE spectra of sigma Her, a nearby binary system, with a main sequence primary, that has a Vega-like infrared excess. We observe absorption in the excited fine structure lines C II* at 1037 A, N II* at 1085 A, and N II** at 1086 A that are blueshifted by as much as ~30 km/sec with respect to the star. Since these features are considerably narrower than the stellar lines and broader than interstellar features, the C II and N II are circumstellar. We suggest that there is a radiatively driven wind, arising from the circumstellar matter, rather than accretion as occurs around beta Pic, because of sigma Her's high luminosity. Assuming that the gas is liberated by collisions between parent bodies at 20 AU, the approximate distance at which blackbody grains are in radiative equilibrium with the star and at which 3-body orbits become unstable, we infer dM/dt ~ 6 * 10^-12 M_{sun}/yr. This wind depletes the minimum mass of parent bodies in less than the estimated age of the system.Comment: 6 pages, 3 figures, ApJ in pres

Efficiency Centered Maintenance of Preheat Train of a Crude Oil Distillation Unit

Nowadays, maintenance is based on the synergistic integration of operational reliability and timely maintenance, which guarantees the required availability and optimal cost. Operational reliability implies producing more, better performance, longer life, and availability. Timely maintenance involves the least time out of service, fewer maintenance costs, fewer operating costs, and less money. In this work, we study the preheating train of a crude distillation unit of a refinery, which processes 994 m3/h, which presents a formation of a foulinglayer inside it. Among the impacts of fouling is the reduction in the effectiveness of heat transfer, the increase in fuel consumption, the increase in CO2 emissions, the increase in maintenance costs, and the decrease in the profit margin of process. An appropriate cleaning program of the surface of the heat exchanger network is necessary to preserve its key performance parameters, preferably close to design values. This paper presents the maintenance method centered on energy efficiency, to plan the intervention of the preheating train equipment maintenance, which considers the economic energy improvement and the cost of the type of maintenance. The method requires the calculation of the fouling evolution from which the global heat transfer coefficient is obtained, and the heat flux is determined as a function of time. It was observed that, as time passes, the resistance provided by fouling increases and that the overall heat transfer coefficient decreases. The energy efficiency centered maintenance has an indicator of economic justification (factor J) that relates the economic-energy improvement achieved when performing maintenance, taking into account the economic effort invested. Depending on the cost of the type of maintenance to be performed, a threshold should be chosen, from which the maintenance activity is justified. The effectiveness values of the heat exchanger (e) and the J indicator are used to form a criticality matrix, which allows prioritizing maintenance activities in each equipment. The planning of the implementation dates of the maintenance of each heat exchanger, from the maintenance method centered on energy efficiency applied to the crude distillation unit's, preheat train, constitutes a contribution in this specific field. The conceptual design of the maintenance method centered on energy efficiency presented in this work is feasible for other heat transfer equipment used in oil refineries and industry in general. The procedure developed uses real operation values, and with its implementation, a saving of 150000 US dollars was achieved. © 2020 ASME

INFORMATION AND COMMUNICATION TECHNOLOGIES IN THE NATIONAL UNIVERSITY OF EDUCATION OF ECUADOR

El presente estudio es un avance parcial de una investigación en curso que tiene por objeto principal la creación, contribución y el análisis de indicadores culturales en el contexto universitario ecuatoriano. Este trabajo se enfoca específicamente en proveer una serie de indicadores sobre el equipamiento, uso y consumo de las TIC de los estudiantes de la Universidad Nacional de Educación de Ecuador (UNAE). La metodología usada es de orden cuantitativo/descriptiva, a partir de los datos recolectados en una encuesta aplicada a una muestra compuesta de 438 estudiantes del total del universo entre las diferentes carreras y ciclos ofertados por la UNAE. La muestra tiene un nivel de confianza del 95% y un 5% de margen de error. Los resultados obtenidos muestran un alto nivel de equipamiento, uso y consumo de diferentes dispositivos tecnológicos. También, esta población universitaria usa su tiempo en actividades académicas y de ocio con su celular, televisión, videos e internet.This study is a partial advance of ongoing research whose main objective is the creation, contribution, and analysis of cultural indicators in the Ecuadorian university context. This work focuses specifically on providing a series of indicators on the equipment, use, and consumption of the TIC of students of the National University of Education of Ecuador (UNAE). The methodology used is the quantitative of descriptive-analytical order, based on the data collected in a survey applied on a population sample, made up of 438 students of the total universe between the different careers and cycles offered by the UNAE. The sample has a margin of 95% reliability and an error of 5%. The obtained results showed a high level of equipment, use, and consumption of the different technological devices. Also, this university population spends daily hours in academic and free time activities in cellphones, television, videos, and internet

Overseas and home students’ perspectives towards the implementation of portfolio-based timed-writing technique in composition class

This inquiry addressed students’ perspectives towards the implementation of the Portfolio-Based Timed-Writing Technique (PBTHT) under an international transfer credit (ICT) program at Universitas Muria Kudus. It is to answer the following questions: (1) What are the overseas students’ perspectives towards the PBTHT implementation? (2) How do their perspectives compare to their home counterparts? Using narrative analysis, this study qualitatively revealed that PBTHT is a new technique for overseas students. Their perspectives show their composition strengths cover the use of proper grammar, spelling, and mutually supportive essay elements. Meanwhile, their weaknesses include the content and mechanics. Overseas and home students expressed different perspectives due to different experiences, abilities, and teaching processes in their respective countries. Both groups acknowledged that the PBTHT implementation help them with the improvement of their writing skills

Caracterização molecular parcial de um isolado de Prunus necrotic ringspot virus de roseira.

O objetivo deste trabalho foi identificar o agente causal do mosaico da roseira e caracterizar um isolado de PNRSV de roseira