Modeling of weeds interference periods in bean

The research objective was to determine the effects of spacing and seeding density of common bean to the period prior to weed interference (PPI) and weed period prior to economic loss (WEEPPEL). The treatments consisted of periods of coexistence between culture and the weeds, with 0 to 10, 0 to 20, 0 to 30, 0 to 40, 0 to 50, 0 to 60, 0 to 70, and 0 to 80 days and a control maintained without weeds. In addition to the periods of coexistence, there were still studies with an inter-row of 0.45 and 0.60 m, 10 and 15 plants m-1. The experimental delineation used was randomized blocks with four repetitions per treatment. The grain productivity of the culture had a reduction of 63, 50, 42 and 57% when the coexistence with the weed plants was during the entire cycle of the culture for a row spacing of 0.45 m and a seeding density of 10 and 15 plants per meter; and a row spacing of 0.60m and a seeding density of 10 and 15 plants per meter, respectively. The PPI occurred in 23, 27, 13, and 19 days after crop emergence and WEEPPEL in 10, 9, 8, and 8 days, respectively.

Interferencia de malezas en el cultivo de frijol en dos sistemas de labranzas

Con este trabajo, se busco determinar el período anterior a la interferencia de las malezas que conviven con el cultivo de frijol, en ausencia o presencia de residuos vegetales de Crotalaria juncea. Los tratamientos estaban constituidos de siete períodos de convivencia del cultivo con las malezas: 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 y 0-70 días después de la emergencia y también de un testigo sin presencia de las malezas en ausencia o presencia de crotalaria. El diseño experimental utilizado fue de bloques completos seleccionados al azar, con cuatro repeticiones por tratamiento. Hubo reducciones de 40,6% y 55,1% en la productividad de granos de frijol en convivencia con malezas durante todo el ciclo del cultivo, en ausencia y presencia de los residuos vegetales, respectivamente. Se concluyó que la productividad de granos fue afectada negativamente a partir de 29 y 38 días después de la emergencia, sin y con residuos, respectivamente, y eso constituyó los períodos anteriores a la interferencia.

Comparação entre métodos para determinar o período anterior à interferência de plantas daninhas em feijoeiros com distintos tipos de hábitos de crescimento

A interferência causada pelas plantas daninhas pode reduzir em até 80% a produtividade de grãos do feijão quando não manejadas de forma correta. Portanto, a decisão sobre o momento de controlá-las é um dos principais aspectos do manejo integrado. Nesse sentido, objetivou-se com este trabalho determinar o período anterior à interferência das plantas daninhas (PAI) em cultivares de feijão com diferentes tipos de hábitos de crescimento. Adotou-se o delineamento experimental de blocos casualizados com quatro repetições. Os tratamentos experimentais foram constituídos de dez períodos de convivência da cultura com as plantas daninhas: 0-7, 0-14, 0-21, 0-28, 0-35, 0-42, 0-49, 0-56, 0-97 (colheita) dias após a emergência (DAE) e mais uma testemunha sem convívio com as plantas daninhas. O PAI foi determinado por meio de distintas abordagens: o nível arbitrário de 5% de perda na produtividade, o nível de tolerância (NT) e o de dano no rendimento econômico (PADRE). O PAI obtido foi diferente em todas as abordagens, e os feijoeiros de crescimento indeterminado tipo II apresentaram os menores tempos de convivência.

Morfoanatomia e ontogênese do pericarpo de Manihot caerulescens Pohl e M. tripartita Müll. Arg. (Euphorbiaceae)

Manihot caerulescens e M. tripartita são espécies arbustivas de cerrado, conhecidas como mandioca-brava. Não são encontrados muitos trabalhos sobre estrutura do pericarpo de Euphorbiaceae e muitas das descrições morfológicas existentes apresentam interpretações dúbias, especialmente sobre a deiscência. O presente trabalho objetivou descrever a morfologia, anatomia e ontogênese do pericarpo das duas espécies de Manihot, comparando-as entre si e relacionando aspectos estruturais do pericarpo à deiscência. Verificou-se que o desenvolvimento do pericarpo enquadra-se em quatro estágios, típicos de frutos secos. Dois meristemas são formados: um subadaxial, que produz o mesocarpo interno; outro adaxial, que forma o endocarpo, homogêneo e colenquimatoso em M. caerulescens, e heterogêneo em M. tripartita, com fibroesclereídes gelatinosas externas e uma porção colenquimatosa interna. Observou-se a formação de tecido de separação, composto por parênquima laxo, em direção aos feixes dorsais dos três carpelos e aos septos, o qual é mais evidente em M. tripartita. Por fim, verificou-se variação na composição do estrato esclerenquimático: em M. caerulescens, há uma faixa de fibroesclereídes e uma de braquiesclereídes, ambas do mesocarpo; em M. tripartita, ocorrem essas duas faixas mesocárpicas, com maior espessura, acrescidas do endocarpo externo, também composto por fibroesclereídes. Os frutos de ambas as espécies são cápsulas, cujo tipo varia em função do desenvolvimento do tecido de separação e da amplitude do estrato esclerenquimático. Assim, M. caerulescens apresenta cápsulas indeiscentes, enquanto M. tripartita forma cápsulas septi-loculicidas, uma vez que a deiscência, embora passiva, ocorre nas regiões dorsais e em direção aos septos.

Assessment of tidal volume and thoracoabdominal motion using volume and flow-oriented incentive spirometers in healthy subjects

The objective of the present study was to evaluate incentive spirometers using volume- (Coach and Voldyne) and flow-oriented (Triflo II and Respirex) devices. Sixteen healthy subjects, 24 ± 4 years, 62 ± 12 kg, were studied. Respiratory variables were obtained by respiratory inductive plethysmography, with subjects in a semi-reclined position (45º). Tidal volume, respiratory frequency, minute ventilation, inspiratory duty cycle, mean inspiratory flow, and thoracoabdominal motion were measured. Statistical analysis was performed with Kolmogorov-Smirnov test, t-test and ANOVA. Comparison between the Coach and Voldyne devices showed that larger values of tidal volume (1035 ± 268 vs 947 ± 268 ml, P = 0.02) and minute ventilation (9.07 ± 3.61 vs 7.49 ± 2.58 l/min, P = 0.01) were reached with Voldyne, whereas no significant differences in respiratory frequency were observed (7.85 ± 1.24 vs 8.57 ± 1.89 bpm). Comparison between flow-oriented devices showed larger values of inspiratory duty cycle and lower mean inspiratory flow with Triflo II (0.35 ± 0.05 vs 0.32 ± 0.05 ml/s, P = 0.00, and 531 ± 137 vs 606 ± 167 ml/s, P = 0.00, respectively). Abdominal motion was larger (P < 0.05) during the use of volume-oriented devices compared to flow-oriented devices (52 ± 11% for Coach and 50 ± 9% for Voldyne; 43 ± 13% for Triflo II and 44 ± 14% for Respirex). We observed that significantly higher tidal volume associated with low respiratory frequency was reached with Voldyne, and that there was a larger abdominal displacement with volume-oriented devices.

Breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises

The objective of the present study was to evaluate breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises: diaphragmatic breathing (DB), flow-oriented (Triflo II) incentive spirometry and volume-oriented (Voldyne) incentive spirometry. Seventeen healthy subjects (12 females, 5 males) aged 23 ± 5 years (mean ± SD) were studied. Calibrated respiratory inductive plethysmography was used to measure the following variables during rest (baseline) and breathing exercises: tidal volume (Vt), respiratory frequency (f), rib cage contribution to Vt (RC/Vt), inspiratory duty cycle (Ti/Ttot), and phase angle (PhAng). Sternocleidomastoid muscle activity was assessed by surface electromyography. Statistical analysis was performed by ANOVA and Tukey or Friedman and Wilcoxon tests, with the level of significance set at P < 0.05. Comparisons between baseline and breathing exercise periods showed a significant increase of Vt and PhAng during all exercises, a significant decrease of f during DB and Voldyne, a significant increase of Ti/Ttot during Voldyne, and no significant difference in RC/Vt. Comparisons among exercises revealed higher f and sternocleidomastoid activity during Triflo II (P < 0.05) with respect to DB and Voldyne, without a significant difference in Vt, Ti/Ttot, PhAng, or RC/Vt. Exercises changed the breathing pattern and increased PhAng, a variable of thoracoabdominal asynchrony, compared to baseline. The only difference between DB and Voldyne was a significant increase of Ti/Ttot compared to baseline. Triflo II was associated with higher f values and electromyographic activity of the sternocleidomastoid. In conclusion, DB and Voldyne showed similar results while Triflo II showed disadvantages compared to the other breathing exercises.

Breathing pattern and thoracoabdominal motion during exercise in chronic obstructive pulmonary disease

Subjects with chronic obstructive pulmonary disease (COPD) present breathing pattern and thoracoabdominal motion abnormalities that may contribute to exercise limitation. Twenty-two men with stable COPD (FEV1 = 42.6 ± 13.5% predicted; age 68 ± 8 years; mean ± SD) on usual medication and with at least 5 years of diagnosis were evaluated at rest and during an incremental cycle exercise test (10 watts/2 min). Changes in respiratory frequency, tidal volume, rib cage and abdominal motion contribution to tidal volume and the phase angle that measures the asynchrony were analyzed by inductive respiratory plethysmography at rest and during three levels of exercise (30-50, 70-80, and 100% maximal work load). Repeated measures ANOVA followed by pre-planned contrasts and Bonferroni corrections were used for analyses. As expected, the greater the exercise intensity the higher the tidal volume and respiratory frequency. Abdominal motion contributed to the tidal volume increase (rest: 49.82 ± 11.19% vs exercise: 64.15 ± 9.7%, 63.41 ± 10%, and 65.56 ± 10.2%, respectively, P < 0.001) as well as the asynchrony [phase angle: 11.95 ± 7.24° at rest vs 22.2 ± 15° (P = 0.002), 22.6 ± 9° (P < 0.001), and 22.7 ± 8° (P < 0.001), respectively, at the three levels of exercise]. In conclusion, the increase in ventilation during exercise in COPD patients was associated with the major motion of the abdominal compartment and with an increase in the asynchrony independent of exercise intensity. It suggests that cycling exercise is an effective way of enhancing ventilation in COPD patients.