Da Silva R.G.,UFERSA |
Maia A.S.C.,São Paulo State University |
de Macedo Costa L.L.,Federal Rural University of the Semiarid Region
International Journal of Biometeorology | Year: 2015
This paper presents a new thermal stress index for dairy cows in inter-tropical regions, with special mention to the semi-arid ones. Holstein cows were measured for rectal temperature (TR), respiratory rate (FR) and rates of heat exchange by convection (C), radiation (R), skin surface evaporation (ES) and respiratory evaporation (ER) in the north eastern region of Brazil, after exposure to sun for several hours. Average environmental measurements during the observations were air temperature (TA) 32.4 °C (24.4–38.9°), wind speed (U) 1.8 m.s−1 (0.01–11.0), relative humidity 63.6 % (36.8–81.5) and short-wave solar radiation 701.3 W m−2 (116–1,295). The effective radiant heat load (ERHL) was 838.5 ± 4.9 W m−2. Values for the atmospheric transmittance (τ) were also determined for tropical regions, in order to permit adequate estimates of the solar radiation. The average value was τ = 0.611 ± 0.004 for clear days with some small moving clouds, with a range of 0.32 to 0.91 in the day period from 1000 to 1300 hours. Observed τ values were higher (0.62–0.66) for locations near the seacoast and in those regions well-provided with green fields. Effects of month, location and time of the day were all statistically significant (P < 0.01). A total of 1,092 data were obtained for cows exposed for 1 to 8 h to sun during the day; in 7 months (February, March, April, July, August, September and November), 4 days per month on the average. A principal component analysis summarised the TR, FR, C, R, ES and ER measurements into just one synthetic variable (y1); several indexes were then obtained by multiple regression of y1 on the four environmental variables and its combinations, by using Origin 8.1 software (OriginLab Corp.). The chosen equation was the index of thermal stress for cows, ITSC = 77.1747 + 4.8327 TA − 34.8189 U + 1.111 U2 + 118.6981 PV − 14.7956 PV 2 − 0.1059 ERHL with r2 = 0.812. The correlations of ITSC with TR, FR, C, ES, R and ER were 0.275, 0.255, −0.493, −0.647, −0.818 and 0.075, respectively. Correlations of the index with the physiological variables are presented, and ITSC is compared to three other indexes. © 2014, ISB.
Do Carmo B.B.T.,UFERSA |
Pontes R.L.J.,UFC Virtual Institute
International Journal of Engineering Education | Year: 2013
The development of the Internet has led to a great transformation in different spheres of society, including education. The question discussed in this research is not whether this transformation is positive or negative. This study aims to discuss the potentialities of Web 2.0 tools in education, observing how it can be used in Engineering Education models. The question that we want to help answer is: How can engineering professors use Web 2.0 tools, for example in a blog, in teaching strategies to create a motivational learning space? A methodology based on collaborative learning was proposed to students in the Industrial Engineering Fundamentals discipline using Web 2.0 tools to evaluate its potential to aid autonomous learning. It was concluded that Web 2.0 tools have a large potential in Engineering Education. This methodology created a space in which students have a more active role in the learning process. © 2013 TEMPUS Publications.
Dantas D.D.C.,UFERSA |
de Medeiros J.F.,Rural University |
Freire A.G.,Federal University of Ceará
Revista Ciencia Agronomica | Year: 2011
The need for techniques that increase the yield of melon with fruit in obtaining desirable traits by consumers, with high content of soluble solids and pulp firmness, good flavor and good external appearance, is a reality. The soil cover with polyethylene films is a technique that was introduced in the agro-pole Assu-Mossoró-Baraúna to meet this demand. The objective of this study was to evaluate the yield and fruit quality of yellow melon grown with four irrigation depths (L1 -100%, L2 - 91%, L3 - 82%, L4 - 72% of the standard depth of 452 mm which was determined by the methodology of the FAO Kc dual) and tree types of polyethylene film (white-black, silver-black, black-black) used for the soil cover, compared with cultivation without coverage. Was used the randomized block design with split plot into 4 × 4, and four replications. The use of polyethylene films provided a significant increase in yield, and the increase of fruit weight by 20% on average, compared to treatment without coverage; the polyethylene film of white-black and black-black were better in relation to the silver-black color; the standard depth of 452 mm can be reduced by 28% without yield reduction even with the average fruit weight decrease by 11%; the concentration of soluble solids decreased as the irrigation was reduced due to heavy pest attack.
De Oliveira F.D.A.,UFERSA |
De Medeiros J.F.,UFERSA |
Duarte S.N.,University of Sao Paulo |
Engenharia Agricola | Year: 2011
The satisfactory results obtained in monitoring soil salinity and ion concentration, by means of porous ceramic cup extractors, motivated the realization of this study, which objective was obtaining calibration curves for these extractors to monitor soil electrical conductivity and concentration of nitrate and potassium in two different soils. The nitrate concentrations tested were the same for the two soils (0; 84; 168; 252; 336; 420 and 504 mg L -1) but, for potassium, different concentrations were used for sandy soil (0; 117; 234; 351; 468; 585 and 702 mg L -1) and clay soil (0; 117; 234; 351; 468; 585; 702; 1,170; 1,755; 2,340; 2,925 and 3,510 mg L -1). Electrical conductivity of soil solution and concentrations of nitrate and potassium were estimated with satisfactory precision from soil solution collected with porous ceramic cup extractors, but this task must be preceded by a calibration for each soil type.
Neto S.A.G.,Rural University |
Sakamoto S.M.,UFERSA |
Soto-Blanco B.,Federal University of Minas Gerais
Ciencia Rural | Year: 2013
A study was conducted aiming to determine the plants species poisoning of zootechnical interest in 35 cities from Central and West regions of Rio Grande do Norte state, Brazil. It was interviewed 180 farmers, 20 veterinarians, 12 agriculture experts, and 5 agronomists. Data obtained in the interviews were compiled and analyzed using the software Epi Info version 6.04. The plant species responsible by greater number of poisoning outbreaks were Ipomoea asarifolia, Aspidosperma pyrifolium, Indigofera suffruticosa, Manihot carthaginensis subsp. glaziovii, Amorimia septentrionalis, Tephrosia cinerea, Anadenanthera colubrina var. cebil, Marsdenia megalantha, Anacardium occidentale, Cnidoscolus quercifolius, Crotalaria retusa, Froelichia humboldtiana, Ipomoea carnea, Leucaena leucocephala, Manihot esculenta, Mimosa tenuiflora, Nerium oleander, Prosopis juliflora, Ricinus communis, Sorghum bicolor, Sorghum halepense, and Urochloa (Brachiaria) decumbens.
de Morais F.A.,UFERSA |
Gurgel M.T.,DCAT UFERSA |
de Oliveira F.H.T.,DCAT UFERSA |
Revista Ciencia Agronomica | Year: 2011
This experiment was made to evaluate the influence of the irrigation with saline water on growth and production of sunflower (hibrido H251), besides monitoring the evolution of some chemical attributes of the soil along its cycle. The experimental design used was the randomized blocks with six treatments and five replications. The treatments consisted of six different irrigation strategies, five of them with use of saline water. The growth evaluations (plant height, stem diameter and leaf number) were made at 20; 40; 60; 80; 100 days after sowing (DAS). The harvest occurred at 100 DAS, then the capitulum diameter was measured and the weight of 1000 achenes, as well as its productivity, were determined. The soil samples were collected on the same dates of the growth evaluations at the layers of 0-0.10; 0.10-0.30; 0.30-0.50 m. The evaluated soil attributes were Na+, EC and pH, besides of the ratios Na+/Ca2+ and Na+/Mg2+. The sunflower appeared to be tolerant to the salinity of the irrigation water, what means it could be cultivated normally and still have a good production even when the water EC reaches up to 3.53 dS m-1. However, when using a medium/high EC water, it's needed to adopt some practices to control the salinization/sodification of the soil. The tolerance of the sunflower to salinity was not dependent of the development phase. Overall, the chemical attributes of the soil increased and stabilized from the middle of the cycle on.
Coelho M.F.B.,UFERSA |
Maia S.S.S.,UFERSA |
Oliveira A.K.,UFERSA |
Horticultura Brasileira | Year: 2011
Allelopathy is the release of plant substances that inhibit or act as stimulants in the environment, and may be present in the seeds of some species. The objective of this work was to evaluate the allelopatic activity of the extract of juazeiro (Ziziphus joazeiro Mart.) seeds on the germination of lettuce (Lactuca sativa L.) seeds. We utilized the randomized design with four replications and five treatments (0, 25, 50, 75 and 100% of concentration of the crude extract). The crude extract was obtained after the extraction of 50 g of seeds, shaking them with 500 mL of water in a blender. The results showed allelopatic effect, proportional to the increase of the concentration of the extract. The highest concentrations of seed extract of juazeiro affected the percentage and speed of germination and the lowest concentrations caused abnormal seedlings on lettuce seed germination. Therefore, the extract presented an allelopatic effect, unfavorable to the germination of lettuce seeds.
de Medeiros M.A.,UFERSA |
Grangeiro L.C.,UFERSA |
Torres S.B.,UFERSA |
Revista Brasileira de Sementes | Year: 2010
The objective of this study was to evaluate the physical and physiological changes in the maturation of gherkin (Cucumis anguria L.) seeds since these aspects are important for high quality seed production and reducing seed deterioration in the field. Seeds were collected from fruits of the Norte cultivar at five-day intervals from the 15th to the 40th day after anthesis. The statistical design was completely randomized with six treatments (fruit ages) and four replications. For each fruit age, the fruits were evaluated visually and the mean weight determined. The seeds were evaluated regarding: moisture content, seed dry mass, germination, first count of ermination, electrical conductivity, accelerated aging, and emergence speed index. The maximum physiological quality was found in seeds collected 32 days after anthesis but the best time to harvest the fruits was from 35 to 40 days after anthesis when the seeds showed the lowest moisture content.
Torres S.B.,UFERSA |
Dantas A.H.,UFERSA |
Pereira M.F.S.,UFERSA |
Benedito C.P.,UFERSA |
da Silva F.H.A.,UFERSA
Revista Brasileira de Sementes | Year: 2012
Vigor tests are essential in seed quality control programs and the controlled deterioration test may be used for this purpose, especially for vegetable seeds. The objective of this study was to evaluate the methodology of the controlled deterioration test and to verify its effectiveness in identifying different vigor levels of coriander (Coriandrum sativum L.) seed lots. Four cultivars ("Português", "Super Verdão", "Tabocas" and "Verdão"), each represented by three seed lots, were tested for germination, first germination, seedling emergence, speed of emergence, seedling height, dry weight of seedlings and controlled deterioration (seeds with moisture contents of 18, 21 and 24% to 45 °C for 24 and 48 hours). The controlled deterioration test may be used to evaluate the physiological potential of coriander seeds, and the combination of 21% water at 45 °C for 24 hours is the most recommended treatment.
Torres S.B.,UFERSA |
Pereira R.A.,Brazilian National Council for Scientific and Technological Development
Revista Brasileira de Sementes | Year: 2010
Electrical conductivity has been recommended for evaluating seed vigor in peas and other species although research is still needed to improve procedures. The objective of this study was to develop methodology for the electrical conductivity test to evaluate the physiological potential of salad rocket (Eruca sativa L.) seeds. Five seed lots were used for each of two cultivars of salad rocket, "Cultivada" and "Folha Larga". The following tests were made: standard germination, first germination count, accelerated ageing, field emergence and variations in the electrical conductivity test (25 or 50 seeds imbibed in 25 mL, 50 mL or 75 mL of water; at 20 °C, 25 °C and 30 °C; for 1, 2, 4, 8, 12, 16, 20 and 24 hours). The results confirmed the efficiency of the electrical conductivity test to evaluate salad rocket seed vigor. The best combination was 50 seeds immersed in 50 mL of deionized water at 25 °C, for eight hours.