EFFICIENCY of PNEUMATIC and HORIZONTAL PERFORATED DISK METER MECHANISM IN CORN NO-TILLAGE SEEDERS IN SOIL WITH DIFFERENT MOBILIZATION REPORTS

This work objectified to evaluate the efficiency of two meter mechanism of corn seeds when submitted to different forward speed and soil management system during the non-tillage seeding. It was used a factorial design in randomized blocks. The factors whose effects were examined were related to the seeders with pneumatic and horizontal disk meter mechanisms for the distribution of the seeds, to the set tractor-seeder forward speeds (4.4; 8.0 and 9.8 km h(-1)), and to the soil management system considering the corn no-tillage seeding over minimum tillage with chisel plow and the no-tillage system for the seeding of oat culture (Avena strigosa Schreb). It was verified that the forward speed didn't influence the initial and final stands of plants but it interfered in the regularity of longitudinal distribution of plants. The smallest speed provided the largest percentile of normal spacing between plants. The pneumatic meter mechanism presented better performance than the horizontal disk perforated in the longitudinal distribution of plants. About corn productivity aspect it's indifferent the recommendation of use for pneumatic and perforated horizontal disk meter mechanism of seeds.

Avaliação do contato pneu-solo em três modelos de pneus agrícolas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de diferentes intervalos de recuperação entre as séries sobre o desempenho muscular no exercício leg-press em idosas não treinadas

OBJETIVO: Verificar a influência de dois diferentes intervalos de recuperação (IR) entre as séries no exercício leg-press sobre o número e sustentabilidade das repetições e no volume total, em idosas não treinadas. MÉTODOS: Onze idosas (66,5 ± 5,0 anos; 59,2 ± 9,1kg; 146,4 ± 34,9cm) foram submetidas a duas sessões experimentais de exercícios com pesos com intensidade de 15 repetições máximas. Cada sessão experimental foi composta por três séries realizadas até a fadiga muscular utilizando IR de um (IR-1) ou três minutos (IR-3). As sessões experimentais foram separadas por, no mínimo, 48 horas. Todas as participantes realizaram ambos os protocolos e um delineamento cross-over balanceado foi utilizado para determinar a ordem das sessões experimentais. RESULTADOS: Para ambos os IR entre as séries, reduções significativas (P < 0,05) no número e na sustentabilidade das repetições foram observadas da primeira para a segunda e terceira séries e da segunda para a terceira séries. Diferenças significativas (P < 0,05) entre os IR foram observadas nas duas séries finais. O volume total da sessão realizada com IR-3 foi estatisticamente superior (20,4%; P < 0,05) quando comparada a sessão IR-1. CONCLUSÃO: O número e a sustentabilidade das repetições e o volume total de treino de idosas não treinadas são influenciados pelo IR empregado entre as séries. Maiores IR devem ser utilizados quando a finalidade for otimizar o volume de treino por meio da sustentabilidade das repetições. Em contrapartida, menores IR devem ser utilizados quando a meta for obter maiores níveis de fadiga muscular.

Politics, press and military participation in the abdication of d. Pedro I

This work seeks to contribute to a better understanding of the Abdication, analyzing how and why sections of the army joined the liberal groups against the emperor, focusing on the period that immediately preceded this event. The argument is that the alliance between sections of the army and the liberal groups in 1831 was possible because the expansion of the "public space" in the city of Rio de Janeiro, a process in which newspapers such as "O Republico" played a key role as they became a privileged locus for political disputes. The article shows that that newspaper helped to build a political identity based on the defense of Brazilian interests against Portuguese despotism, giving momentum to internal conflicts around this subject that were already taking place among sections of the army and hence triggering the process that would lead to the Abdication.

Electromyographic evaluation of the rectus femoris muscle during exercises performed on the leg press

The rectus femoris was analysed in 10 volunteers during knee flexion and extension with the feet in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an A/D conversion plaque (Model CAD 10/26), software specially designed to record and analyse the signals, Horizontal Leg Press, and electrogoniometers were used. The rectus femoris muscle showed strong potentials at the beginning of knee extension. In the simultaneous bendings of the knee and hip the activity was strong toward the end of the movement. The rectus femoris showed a similar activity both in the upper and lower platforms. As for foot positions, the rectus femoris showed the smallest potentials with the foot in plantar flexion and the largest ones with the foot in dorsal flexion.

Electromyographic behaviour of the gastrocnemius muscle during knee extension and flexion performed on the leg press

The gastrocnemius was analysed in 10 male volunteers during knee flexion and extension with the foot in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an AID conversion plaque (Model CAD 10/26), a software specially designed to record and analyse the signals, a horizontal leg press, and electrogoniometers were used. The gastrocnemius muscle showed strong potentials at the end of knee extension and beginning of knee flexion. The muscle presented a similar activity both in the zipper and lower platforms. As to bilateral action, the right gastrocnemius presented stronger potentials on the upper platforms, whereas the potentials were bilaterally similar on the lower platforms. As for foot position, the gastrocnemius presented strong potentials when the foot was in plantar flexion. The remaining positions had no effect on the work of the muscle.

Electromyographic validation of the trapezius and serratus anterior muscles in military press exercises with open grip.

It was studied the trapezius muscle and serratus anterior muscle in 24 male volunteers using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes, during the execution of four different modalities of military press exercises with open grip. The results showed that TS acted significantly in the modalities standing and sitting press behind neck, while SI acted in all the modalities, i.e., standing and sitting press behind neck and forward, justifying their inclusion as basic exercises for physical conditioning programmes.

Electromyographic validation of the trapezius and serratus anterior muscles in military press exercises with open and middle grip

Electromyographic activity of the trapezius muscle and serratus anterior muscle was analysed in 4 different modalities of military press exercises, each of them with 2 grips: open and middle. It was analyzed 24 male volunteers using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. The TS and SI muscles acted with high and very high activity in all the modalities of military press exercises. Statistically, they did not show significative difference in the performance of the exercises with open and middle grip, justifying the inclusion of this group of exercises with both grips for the physical conditioning programmes.

Electromyographic validation of the trapezius and serratus anterior muscles in military press exercises with middle grip

Electromyographic activity of the trapezius muscle and serratus anterior muscle was analysed in 24 male volunteers using a 2-channel TECA TE 4 electromyograp, during the execution of four different modalities of military press exercises with middle grip. The trapezius acted preferentially in the modalities standing press behind neck; and sitting forward and press behind neck, while SI did not show any significative difference among the modalities. The high levels of action potentials with which TS and SI acted justify the inclusion of these exercises in physical programmes.

Geotechnical and structural behavior of the railroad track in large-scale apparatus

This paper analyses the static and dynamic behavior of the railroad track model in laboratory. Measurements of stresses and strains on a large-scale railroad track apparatus were studied. The model includes: compacted soil, representing the final layers of platform, ballast layer, and ties (steel, wooden, and pre-stressed concrete). The soil and soil ballast interface were instrumented with pneumatic stress gauge. Settlement measurement device were positioned at the same levels as the load cells. Loads were applied by hydraulic actuators, statically and dynamically. After the prescribed number of load cycles, in pre-determined intervals, stresses and strains were measured. Observations indicate that stress and strain distributions, transmitted by wooden or steel ties, behave similarly. A more favorable behavior was observed with pre-stressed concrete mono block ties. Non-linear response was observed after a threshold numbers of cycles were surpassed, showing that the strain modulus increases with the numbers of cycles. © 2009 IOS Press.

Electromyographic validation of the muscles deltoid (anterior portion) and pectoralis major (clavicular portion) in military press exercises with open grip

It was analized the deltoid muscle anterior portion and the pectoralis major clavicular portion in 24 male volunteers using a two-channel electromyograph TECA TE 4, and Hewllet Packard surface electrodes, in 4 modalities of military press exercises with open grip. The results showed high inactivity for PMC in almost all the modalities while DA developed very high levels of action potentials in all the modalities assessed.

Electromyographic validation of the muscles deltoid (anterior portion) and pectoralis major (clavicular portion) in military press exercises with middle grip

With the objective to know the electromyographic activity normal parameters of the deltoid (anterior portion) and pectoralis major (clavicular portion) muscles in the different modalities of military press exercises with middle grip, we analyzed 24 male volunteers using a two-channel electromyograph TECA TE 4, and Hewllet Packard surface electrodes. It was observed high inactivity levels for PMC in almost all the modalities and the concentration in the active cases, mainly, in the weak potential, while DA presented very high levels of much strong action potentials in all the modalities assessed.

Electromyographic validation of the deltoid (anterior portion) and pectoralis major (clavicular portion) in military press exercises with open and middle grips

The deltoid (anterior portion) and pectoralis major (clavicular portion) were evaluated in several execution ways of military press exercises with open and middle grips in order to know their behavior pattern. It was analyzed 24 male volunteers, using a 2-channel TECA TE4 electromyograph and Hewllet Packard surface electrodes. It was observed that the execution variation with open and middle grips does not present any significant difference as for the demanding level neither for the pectoralis major muscle nor the deltoid muscle.

Effect of different rest intervals, between sets, on muscle performance during leg press exercise, in trained older women

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Energy expenditure during multiple sets of leg press and bench press

The purpose of this study was to quantify energy expenditure (EE) during multiple sets of leg press (LP) and bench press (BP) exercises in 10 males with at least 1 yr of resistance training (RT). The subjects underwent two sessions to determine 1 repetition maximum (1RM) on the BP and LP and one protocol consisting of a warm up and 4 sets for 10 repetitions at 70% 1RM with a 3-min rest period between sets for each exercise. Energy expenditure was calculated as the sum of oxygen uptake (aerobic component), EPOC, and lactate production (anaerobic component). There were no significant differences in EE between exercises for sets 1 to 4 and the total energy expended. However, statistical analysis revealed a significant difference (P<0.05) between exercises in RT economy (BP, 0.0206 ± 0.0044 kcal·kg-1 vs. LP, 0.0051 ± 0.0015 kcal·kg-1). Within exercise comparison showed set 4 was significantly different from sets 1 and 3 for BP, and for LP a significant difference was found between set 4 and sets 1, 2 and 3. Our results point to an increase in EE during multiple sets at 70% 1RM and show that in spite of the difference in muscle mass involved and total work done during each type of exercise, EE was not different due to greater economy during the LP.