VALTER ARTHUR

VALTER ARTHUR

(Fonte: Lattes)

Resumo

Possui graduação em Biologia pela Universidade Metodista de Piracicaba (1977), mestrado em Energia Nuclear na Agricultura (Esalq) Universidade de São Paulo (1982) e doutorado em Agronomia (Entomologia) (Esalq) Universidade de São Paulo (1985). Atualmente é professor Associado no Centro de Energia Nuclear na Agricultura da Universidade de São Paulo. Tem experiência na área de Agronomia, com ênfase em Radioentomologia (tratamento quarentenário de pragas de importância agrícola) e Irradiação de alimentos (conservação e desinfecção de produtos agropecuários). (Texto extraído do Currículo Lattes em 27 dez. 2021)

Página do item completo

Resultados de Busca

Agora exibindo 1 - 10 de 25

Histological evaluation of Rhipicephalus (Boophilus) microplus tick ovaries subjected to cobalt-60 ionizing radiation
2022 - PASQUALINI, ALEXANDRE A.; ARTHUR, VALTER; SCHIAVOLIN, MICHELEN B.; ABREU, MARINA R. de; CAMARGO-MATHIAS, MARIA I.
Females of Rhipicephalus (Boophilus) microplus ticks ingurgitated and in the prepost phase were submitted to doses of 0, 5, 10, 15, 20 and 25 Gy of Cobalt-60 with the aim of evaluating their effects on ovarian morphohistology with consequent establishment of the degree of damage caused to the reproductive organs of this species. For this purpose, 24 hours after exposure to Co-60 (142 Gy/h) the ectoparasites were dissected and had their ovaries removed and prepared for histology with haematoxylin and eosin staining. The results obtained showed that the 5 Gy dose radiation had a morphological aspect similar to the control standard adopted. The histological sections related to doses of 10 and 15 Gy did not cause many changes in the ovaries, except that changes were observed in the calf granules (size, distribution and staining pattern), as well as the extensive presence of cytoplasmic vacuoles in the ovocytes, especially in the region that makes contact with the ovocyte/pedicel, suggesting the occurrence of changes also in the physiology of the organ. In the ovaries exposed to doses of 20 and 25 Gy, severe alterations were observed in the organ as a whole, as well as in the germ cells (oocytes) which suffered alterations in size and shape, distribution of calf granules, involvement of the DNA present in the germinal vesicle (oocyte nuclei), besides the extensive cytoplasmic vacuolization, alterations which made the maturation of these cells impossible and consequently inhibited the production of new individuals.
Animal welfare provisions in cattery
2022 - ARTHUR, PAULA B.; LEANDRO, RODRIGO S.R.; HARDER, MARCIA N.C.; ARTHUR, VALTER
The present study had the objective of proposing adaptations for a permanent housing environment for neutered cats. Priorities and management practices were characterized by better animals health and quality of life. An animal observation survey was carried out on two different types of catteries: A, where the animals had an environment with greater freedom of movement, and cattery B, with animals with a reduced environment. The problems encountered in each were observed, such as sanitary, nutritional, and especially environmental management. Behavior was taken into account, according to the environment experienced by domestic cats castrated in confinement in the two different types of catteries. Based on the frequency and behavioral sequence of the groups analyzed, it was concluded that the environment of the cattery A promoted greater well-being of the animals.
Glycine max oil physical-chemical quality obtained of irradiated seeds
2021 - FRANCO, J.G.; SILVA, R.M.G. da; SUGUIMOTO, R.Y.; FRANCO, S.S.H.; VILLAVICENCIO, A.L.C.H.; ARTHUR, V.
Ionizing radiation applied to agriculture has mainly benefited food production, as it reduces natural losses caused by physiological processes, as well as eliminating or reducing microorganisms, parasites and pests. In addition, this technique also allows the production of mutants with characteristics of greater productivity, precocity, smaller size, greater resistance to diseases and pests. These mutants are used to obtain new varieties of species of agronomic interest. The objective of this study was to evaluate the physic-chemical quality of the oil extracted from seeds of G. max (soybean) obtained from irradiated seeds with different doses of gamma radiation (0, 25, 50, 75 and 100 Gy of a Cobalt-60 source, type Gammacell-220 installed in CENA-USP). The physic-chemical analyzes included: AOCS Cd-3d-63, AOCS Cd-3-25 and AOCS Cd-1-25, Acids Index (I.A.), Saponification Index (I.S.), Iodide Index (I.I.), respectively. All analytical determinations were performed at least in triplicates. The values found for I.A., for I.S. and for I.I., did not differ from the oil sample obtained from soybean seeds from control subjects (without irradiation) regardless of the concentration and dose of radiation applied to the seeds. The oil analyzed did not show physical-chemical variation in comparison with the oil obtained from non-irradiated seeds, thus suggesting the absence of modifications in these parameters after the genetic improvement induced by the radiation.
Propagation of mango seedlings of the cultivar "Tommy" by grafts irradiated
2021 - FRANCO, S.S.H.; FRANCO, J.G.; FERRARI, L.; LEANDRO, R.S.R.; ARTHUR, P.B.; ARTHUR, V.
Due to difficulties of vegetative propagating of any pants, many tests were performed with ionizing radiation aiming the modification of the characteristics of the plants for obtaining of the improved genotypes and of smaller size. Rootstock “Espada” cultivar, were used to obtain mango seedlings of “Tommy” cultivar. The cuttings were irradiated with different gamma radiation doses: 0 (control), 2.5, 5.0, 7.5 and 10.0 Gy, a dose rate of 0.323 kGy/h, in a source of Cobalt-60 type Gammacell-220, installed in the Center for Nuclear Energy in Agriculture, CENA-USP. After irradiation, was performed the grafting type cleft graft. It was made the first evaluation of height of the plants from the budding grafting after 24 months. Data were subjected by statistic program (SAS) and the means were compared by Tukey test (p <0.05). From the results obtained can be concluded that the doses of 2.5 Gy stimulated growth of the plants and the lethal dose was 10.0 Gy because don’t have development of plants.
Sterilizing of Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae) irradiated in pupa stage
2021 - ARTHUR, P.B.; VILLAVICENCIO, A.L.C.H.; HARDER, M.N.C.; MACHI, A.R.; LEANDRO, R.S.R.; ARTHUR, V.
The use of irradiation process in stored grain may be the solution for the losses caused in these products by insects, as it does not induce resistance in the insects and leaves no toxic residue, and is considered an efficient and safe method of control of insects. The aim of the experiment was to determine the sterilizing dose of ionizing radiation from cobalt-60 to Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae) in peanuts irradiated in pupa stage. The experiment was conducted in the laboratory of Radiobiology and Environment of the Center for Nuclear Energy in Agriculture - CENA / USP., Piracicaba, SP, Brazil. Peanuts samples infested with pupae of A. diaperinus were utilized in the experiment that consisted of 8 treatments with 5 repetitions. Each repetition consisted of 20 pupae a total of 100 individuals per treatment. Were irradiated with doses of 0 (control), 25, 50, 75, 100, 125, 150 and 175 Gy, in a source of cobalt-60, Gammacell-220 type, with a rate dose of 381Gy / h. The experiment was conducted in a controlled temperature of 25 ± 5 ° C and relative humidity of 70 ± 5%. After of irradiation process was evaluated of the number of emerged adult insects in each repetition in the treatments. The results showed that the sterilizing dose in F1 generation was 125 Gy and the pupa lethal dose 150 Gy. The dose of 150 Gy of gamma radiation can be used as phytosanitary treatment to control of immature stages of A. diaperinus infested peanuts.
Disinfestation of mangoes haden infested by Anastrepha fraterculus (Wied., 1830) (Diptera, Tephritidae) with gamma radiation
2021 - ARTHUR, P.B.; MACHI, A.R.; LEANDRO, R.S.R.; HARDER, L.N.C.; HARDER, M.N.C.; ARTHUR, V.
The objective of experiment was determinate the radiation dose for disinfestation to mango Mangifera indica cv. Haden, infested by Anastrepha fraterculus larvae. For realization of the experiment, were collected fruits in the field, which were taking to Entomology laboratory where there was an infestation by the flies in cages during 72 hours period. Waited for the development of the larvae 5 and 8 days to infestation, after the mangos were irradiated in a Cobalt-60 source with doses of: 0(control), 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1.100, 1.200 and 1.300 Gy. After the irradiation, the fruits were placed in climate chamber with 25 ±5°C of temperature and 70±5% of relative humidity. Waited the larvae exit to out of the fruit until the transformation in pupae and adult stage. By the results obtained we can concluded that the lethal dose to larvae in mangoes infested with 5 and 8 days were 600 Gy and 1.000 Gy (0.6 and 1 kGy) respectively. The dose of 50 Gy prevented the total adult emergence for both treatments.
Application of gamma radiation in pea (Pisum sativum L.) in nature to inhibit sprouting and increase shelf life
2021 - ALBANO, A.M.S.; ARTHUR, V.
The irradiation of fresh post-harvest foods has as main interests: inhibit sprouting, increase shelf life, reduce or delay damage caused by insects and diseases. This work is a preliminary study on the use of gamma radiation in fresh peas grains (Pisum sativum L.) in order to evaluate its effects on the inhibition of sprout and its increase in shelf life. The peas were submitted at irradiation process with four radiation doses: 0 (control), 0.15, 0.30 and 0.45 kGy, in a 60Co research irradiator, with a dose rate of 0.323 kGy/h. After irradiation the samples were stored at 8 °C, being evaluated at 1, 7, 14 and 21 days by analyzes of: visual aspect, weight loss, color, hardness, pH, total soluble solids, total titratable acidity, ratio SST/TTA, water content and ash. By the results it was observed that in all parameters analyzes with gamma radiation doses used did not affect significantly in the shelf life of grains. The 0.30 kGy dose increased the germination of the peas and the 0.45 kGy dose was not sufficient to inhibit the sprouting of the peas.
Shelf-life of papaya nectar submitted to ionizing radiation
2021 - HARDER, M.N.C.; ANDRADE, T.; REIS, F.M.; FEITOSA, N.M.; PEREIRA, P.; ROBERTO, S.P.; NEME-OYAN, F.F.; HARDER, L.N.C.; OLIVEIRA, S.R.; ARTHUR, V.
A kind of drink consumption that has grown and appreciated for the most people is the nectar. The papaya nectar was recognized as a differentiated form of this fruit, with which the industry also gains in time of conservation, since the papaya is an extremely perishable fruit. The aim of this study was to evaluate gamma radiation as a way of conserving papaya nectar. The nectar was developed and subjected to gamma radiation at the dose of 1 kGy in a dose tax of 0.356 kGy.hour-1 and compared this treatment with the control group (0 kGy). According to the results obtained, it can be concluded that the dose used was adequate for the conservation of this product for the period evaluated reaching the aim.
Apple porridge submitted to gamma radiation for shelf-life extended
2021 - HARDER, M.N.C.; BREVIGLIERI, E.; OLIVEIRA, B.B.; ZAMBONI, K.; CARVALHO, S.; NEME-OYAN, F.F.; HARDER, L.N.C.; OLIVEIRA, S.R.; ARTHUR, V.
Among many apple products, apple porridge is a popular product nowadays. It is a practical, healthy and tasty product that can be consumed throughout the day. However, it is an extremely perishable product. Therefore, the aim of this work was to evaluate the shelf-life period of apple porridge after the application of gamma radiation as a conservation technology. After the formulation of apple porridge was developed, which was subjected to gamma radiation at the dose of 1kGy in a dose tax of 0.356 kGy.hour-1 and compared this treatment with the control group (0kGy). From the results presented, it can be concluded that the conservation period of apple porridge submitted to gamma radiation is 60 days. From the 90th day, the samples showed microbial growth, becoming not accepted for consumption. In comparison to the control group, the use of gamma radiation was promising, since the standard sample showed contamination before 30 days. By the results it can be concluded that the dose used was adequate for the conservation of this product for the period evaluated.
Efeito do cobalto-60 em fêmeas R. (B) microplus na postura e na incubação dos ovos
2020 - PASQUALINI, ALEXANDRE A.; ARTHUR, VALTER
Este trabalho buscou avaliar os efeitos do Co60 na postura de fêmeas ingurgitas do carrapato R.(B) microplus na fase de pré postura e na eclodibilidade de seus ovos quando submetidas às doses de 0 a 400 Gy onde se constatou que a radiação ionizante afetou em aproximadamente 70% o peso da postura dos ovos destas fêmeas, que a taxa de eclosão dos ovos da Testemunha foi 68,2% maior que a menor dose ionizante, o Tratamento com 5 Gy, que quanto maior a dose de radiação, menor o índice de eclosões e nos tratamentos que receberam doses maiores de 20 Gy, não ocorreram eclosões das posturas, estabelecendo-se assim um marco para se estudar a aplicação de técnica do inseto estéril neste espécime.