Teaching Sciences in Virtual Worlds with Mastery Learning: A Case of Study in Elementary School

Virtual worlds are 3D environments that provide a feeling of immersion and a high degree of interaction, collaboration, communication between users. Its applicability can be focused on the educational scope, in which theories can be integrated as the basis to didactic activities carried out in the 3D environment, being its area of interdisciplinary comprehension. In this context, this article presents the use of a Virtual World built to assist in the teaching of Science for students of the middle school, whose articulation of the activities performed in the course are based on the precepts of the educational theory Mastery Learning. Tests were carried out in the subject of science, being divided into two periods with different groups for comparative purposes and realized evaluations during the period of the experiments. Kruskal-Wallis and Wilcoxon-Mann-Whitney non-parametric test were applied to the results of the assessments to ascertain the performance of each group. It was verified in the general analyzis that the participants who used the Virtual World had a growing performance, with high medians and adequate distribution of the results, being predominant of a smaller variability and amplitude. Thus, was possible to conclude that the results obtained with the approach were positive, which led to the validation of this research and presented a clear contribution to the academic environment

Performance of Braford steers grazing on cultivated pastures and fed or not fed an energy supplement

This experiment evaluated the performance of 84 Braford steers grazing on summer and winter cultivated pastures fed or not fed an energy-protein supplement. Steers were 10 months old and weighed, on average, 165 kg at the beginning of the trial. Steers grazed on cultivated winter pasture, consisting of black oats (Avena strigosa) and ryegrass (Lolium multiflorum Lam.), and then on cultivated summer pasture, consisting of Napier grass (Pennisetum purpureum). The following treatments were applied: SS - supplement was fed during both seasons; SN - supplement was fed only during the winter; NS - supplement was fed only during the summer; and NN - steers were not fed any supplement. Supplementation resulted in higher body weight and better body condition score (SS: 369.2 and 4.52; SN: 335.2 and 4.01; NS: 352.5 and 4.49; SS: 322.5 and 3.83). Longissimus dorsi area was larger in supplemented steers, which also presented thicker backfat when compared with those not fed any supplement (3.67 and 2.29 mm, respectively)

Photosynthetic activity and grape yield of 'Alicante Bouschet' (Vitis vinifera L.) grapevines submitted to nitrogen supply methods and doses.

The great majority of sandy soils present low nitrogen availability, generally below vines physiological demand, and therefore nitrogen fertilizer application, such as urea, is necessary. However, when urea is applied on the soil surface, the vine can use only a small amount of N. Thus, management strategies such as fertigation can increase N utilization by vine, reflecting in a greater photosynthetic activity and grape yield. The objective of this study was to evaluate the influence of nitrogen supply methods and doses on photosynthetic activity and grape yield of 'Alicante Bouschet' grapevines cultivated in sandy soil. The experiment was carried out in Santana do Livramento, in the southern region of Brazil, in a vineyard planted in 2011. The cultivar was 'Alicante Bouschet' grafted on '1103 Paulsen'. The experimental design was of randomized blocks in a bifactorial arrangement (dose x method). The N source used was urea (45 % N). The 0, 20, 60 and 100 kg N·ha-1 doses were applied on the soil surface, without irrigation (NWI) and via fertigation (NF). Photosynthetic activity, N concentration in leaves and grape yield during two growing seasons were evaluated. The application of N doses in soil increased N concentration in grapevine leaves by up to 53 % in NF and 18 % in NWI methods but did not affect yield. Strong correlations between yield and water use efficiency were also observed, evidencing a certain synchronism between the physiological demand of the grapevine and the offer of the adequate N dose by a more efficient method

Growth and reproductive performance of 14- to 15-month-old Hereford heifers

ABSTRACT Aiming at breeding heifers with 14-15 months of age, 100 Hereford calves were subjected to different feeding systems. Heifers grazed on a natural pasture in early winter, fed or not a supplement (14% crude protein; 72% total digestible nutrients), were transferred to a ryegrass pasture for 73 days, and then returned to a natural pasture for 15 days until the beginning of the breeding season. During the last 15 days on ryegrass pasture and the 15 days of the return to the natural pasture, half of the heifers of the two previous systems were offered the supplement, thereby establishing four feeding treatments. Heifers supplemented during the second period, independently of supplementation during the first grazing period, presented higher average daily gain and greater backfat values than the non-supplemented heifers. The breeding season extended for 75 days. At the start of the breeding season (November 18), heifers supplemented during both periods presented higher body condition score and body weight. The highest percentage of puberty was determined in heifers supplemented in the early winter. Heifers supplemented during both periods presented the highest pregnancy rate. Pregnant heifers presented higher average daily gain when fed the supplement during the second period, as well as higher relative pelvic area, body weight, and body condition score at the start and end of the breeding season. To an expressive pregnancy in 14- to 15- month-old heifers, higher weaning weights and pasture allowance are required to get a better answer to supplements offered

Resistência de Cyperus difformis a herbicidas inibidores da ALS em lavoura de arroz irrigado em Santa Catarina

A resistência de plantas daninhas a herbicidas tornou-se preocupação mundial nas últimas décadas. Esse fenômeno caracteriza-se pela capacidade de um biótipo de sobreviver a um tratamento com herbicida que controla os demais indivíduos da mesma população em condições normais de campo e na dose recomendada pelo fabricante na bula. Objetivou-se com este trabalho determinar o nível de resistência de biótipos de Cyperus difformis a herbicidas inibidores da enzima ALS e do fotossistema II. Os tratamentos foram constituídos pelos herbicidas bispyribac-sodium e pyrazosulfuron-ethyl (inibidores da ALS) e bentazon (inibidor do fotossistema II), aplicados em sete doses múltiplas da dose comercial (0,0x, 0,5x, 1x, 2x, 4x, 8x e 16x), sobre duas populações de plantas de C. difformis, quando estas apresentavam de quatro a seis folhas. O biótipo de C. difformis (CYPDI-10) apresentou resistência cruzada aos inibidores da ALS pyrazosulfuron-ethyl e bispyribac-sodium, enquanto o bentazon proporcionou controle eficiente das populações resistente e suscetível. Conclui-se que para manejo das populações de C. difformis resistentes aos inibidores da ALS, em áreas de arroz irrigado de Santa Catarina, devem-se utilizar herbicidas com diferentes mecanismos de ação, associado a outras práticas de manejo, para restringir a expansão das populações resistentes de C. difformis