Early-season plant-to-plant spatial uniformity can affect soybean yields.

Increased soybean (Glycine max L. Merril) seed costs have motivated interest in reduced seeding rates to improve profitability while maintaining or increasing yield. However, little is known about the effect of early-season plant-to-plant spatial uniformity on the yield of modern soybean varieties planted at reduced seeding rates. The objectives of this study were to (i) investigate traditional and devise new metrics for characterizing early-season plant-to-plant spatial uniformity, (ii) identify the best metrics correlating plant-to-plant spatial uniformity and soybean yield, and (iii) evaluate those metrics at different seeding rate (and achieved plant density) levels and yield environments. Soybean trials planted in 2019 and 2020 compared seeding rates of 160, 215, 270, and 321 thousand seeds ha-1 planted with two different planters, Max Emerge and Exact Emerge, in rainfed and irrigated conditions in the United States (US). In addition, trials comparing seeding rates of 100, 230, 360, and 550 thousand seeds ha-1 were conducted in Argentina (Arg) in 2019 and 2020. Achieved plant density, grain yield, and early-season plant-to-plant spacing (and calculated metrics) were measured in all trials. All site-years were separated into low- (2.7 Mg ha-1), medium- (3 Mg ha-1), and high- (4.3 Mg ha-1) yielding environments, and the tested seeding rates were separated into low (< 200 seeds m-2), medium (200-300 seeds m-2), and high (> 300 seeds m-2) levels. Out of the 13 metrics of spatial uniformity, standard deviation (sd) of spacing and of achieved versus targeted evenness index (herein termed as ATEI, observed to theoretical ratio of plant spacing) showed the greatest correlation with soybean yield in US trials (R2 = 0.26 and 0.32, respectively). However, only the ATEI sd, with increases denoting less uniform spacing, exhibited a consistent relationship with yield in both US and Arg trials. The effect of spatial uniformity (ATEI sd) on soybean yield differed by yield environment. Increases in ATEI sd (values > 1) negatively impacted soybean yields in both low- and medium-yield environments, and in achieved plant densities below 200 thousand plants ha-1. High-yielding environments were unaffected by variations in spatial uniformity and plant density levels. Our study provides new insights into the effect of early-season plant-to-plant spatial uniformity on soybean yields, as influenced by yield environments and reduced plant densities.

Mechanical work as a (key) determinant of energy cost in human locomotion: recent findings and future directions.

NEW FINDINGS: What is the topic of this review? This narrative review explores past and recent findings on the mechanical determinants of energy cost during human locomotion, obtained by using a mechanical approach based on König's theorem (Fenn's approach). What advances does it highlight? Developments in analytical methods and their applications allow a better understanding of the mechanical-bioenergetic interaction. Recent advances include the determination of 'frictional' internal work; the association between tendon work and apparent efficiency; a better understanding of the role of energy recovery and internal work in pathological gait (amputees, stroke and obesity); and a comprehensive analysis of human locomotion in (simulated) low gravity conditions. ABSTRACT: During locomotion, muscles use metabolic energy to produce mechanical work (in a more or less efficient way), and energetics and mechanics can be considered as two sides of the same coin, the latter being investigated to understand the former. A mechanical approach based on König's theorem (Fenn's approach) has proved to be a useful tool to elucidate the determinants of the energy cost of locomotion (e.g., the pendulum-like model of walking and the bouncing model of running) and has resulted in many advances in this field. During the past 60 years, this approach has been refined and applied to explore the determinants of energy cost and efficiency in a variety of conditions (e.g., low gravity, unsteady speed). This narrative review aims to summarize current knowledge of the role that mechanical work has played in our understanding of energy cost to date, and to underline how recent developments in analytical methods and their applications in specific locomotion modalities (on a gradient, at low gravity and in unsteady conditions) and in pathological gaits (asymmetric gait pathologies, obese subjects and in the elderly) could continue to push this understanding further. The recent in vivo quantification of new aspects that should be included in the assessment of mechanical work (e.g., frictional internal work and elastic contribution) deserves future research that would improve our knowledge of the mechanical-bioenergetic interaction during human locomotion, as well as in sport science and space exploration.

Effect of different self-selected walking speeds in leveling of body center of mass, mechanical work and energy in healthy children.

PURPOSE: The aim of the study was to analyze the general kinematics of the cycle, leveling of the center of mass and inverted pendulum model in school-age children when they walk at three different auto-selected speeds. METHODS: The kinematics of walking cycle, angular actions that contribute to reducing the vertical displacement of body center of mass (pelvis, hip, knee and ankle) and pendulumlike determining variables (mechanical work, pendulum-like recovery and congruity percentage), were analyzed in children for three different self-selected speeds. Differences for each variable with the speed were tested by ANOVA with Bonferroni post-hoc analysis. Omega squared (ω²) was calculated for the values of the effect sizes. RESULTS: None of the angular variables associated with the leveling of the vertical trajectory of body center of mass changed. Likewise, recovery and congruity percentage presented values similar to those obtained in previous studies and did not show significant changes with the speeds. CONCLUSIONS: Nevertheless, changes in horizontal mechanical work and cycle phases, indicate that at some point during the cycle the mechanical energy transfer may have been affected for speed changes. Our results warn about the implication that small changes in the speed during functional evaluations of gait in children may have.

Experiencia comunitaria en la policlínica de San Antonio, Canelones, Uruguay: algo más que una huerta / Community experience in san antonio primary care health service, canelones, uruguay: "more than a garden

INTRODUCCIÓN. Este artículo presenta una sistematización del Proyecto Redes, Salud y Alimentos llevado adelante por un equipo interdisciplinario de docentes de la Universidad de la República (Udelar) en 2018 en la localidad de San Antonio, Departamento de Canelones, Uruguay. El proyecto tuvo como objetivo promover la creación de un espacio para la promoción integral de la salud y la agroecología desde el enfoque de la Ecosalud. A nivel académico el proyecto se propuso promover la producción de conocimiento interdisciplinario en torno a los ejes de salud humana, construcción social de la salud y producción agroecológica de alimentos. MATERIAL Y MÉTODOS. En el territorio, desde un enfoque de Ecosalud, se generaron acciones de prevención y promoción de la salud a partir de una concepción holística y sistémica de las relaciones ambientales y humanas. Se incorporó la perspectiva agroecológica, considerando a los alimentos y su sistema de producción como determinantes de la sustentabilidad ambiental y de la seguridad y soberanía alimentaria. RESULTADOS. Como resultados destacamos el logro de los objetivos de promover la participación e integración del saber comunitario y haber creado un espacio de promoción de la salud integral, en sintonía con los pilares de la Carta de Shangai, "Promoción de la salud en la Agenda 2030 para el desarrollo sostenible". DISCUSIÓN. Esta experiencia es una respuesta a los desafíos que enfrenta la academia, en su afán de aportar al desarrollo de la sociedad. Sus desarrollos pueden verse también son pilares teóricos y ejes de acción de una nueva Salud Pública. (AU)

INTRODUCTION. This article presents a systematization of the Networks, Health and Food Project carried out by an interdisciplinary team of teachers from the University of the Republic (Ude-lar) in 2018 in the town of San Antonio, Department of Canelones, Uruguay. The main goal was to create a program of health promotion and agroecology from the Eco-health perspective. At an academic level, the project set out to promote the production of interdisciplinary knowledge around the axes of human health, social construction of health and agroecological food production. MATHERIALS AND METHODS. From an Ecohealth approach, health prevention and promotion actions on location were generated from a holistic and systemic conception of the relationship between humans and the environment. The agroecological perspective was incorporated, con-sidering food and its production system as determinants of environmental sustainability and food security and sovereignty. RESULTS. As results we highlight the importance of participation and integration of community knowledge and having created a space for the promotion of comprehensive health, in tune with the pillars of the Shanghai Charter, "Health promotion in the 2030 Agenda for sustainable development". DISCUSSION. This experience is a response to the challenges facing the academy, in its desire to contribute to the development of society. Its developments can also be seen as theoretical support and lines of action of a new Public Health.

Kinematics of male Eupalaestrus weijenberghi (Araneae, Theraphosidae) locomotion on different substrates and inclines.

BACKGROUND: The mechanics and energetics of spider locomotion have not been deeply investigated, despite their importance in the life of a spider. For example, the reproductive success of males of several species is dependent upon their ability to move from one area to another. The aim of this work was to describe gait patterns and analyze the gait parameters of Eupalaestrus weijenberghi (Araneae, Theraphosidae) in order to investigate the mechanics of their locomotion and the mechanisms by which they conserve energy while traversing different inclinations and surfaces. METHODS: Tarantulas were collected and marked for kinematic analysis. Free displacements, both level and on an incline, were recorded using glass and Teflon as experimental surfaces. Body segments of the experimental animals were measured, weighed, and their center of mass was experimentally determined. Through reconstruction of the trajectories of the body segments, we were able to estimate their internal and external mechanical work and analyze their gait patterns. RESULTS: Spiders mainly employed a walk-trot gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected regarding the different planes or surfaces with respect to duty factor, time lags, stride frequency, and stride length. However, postural changes were observed on slippery surfaces. The mechanical work required for traversing a level plane was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all of the total mechanical work. The internal work was extremely low and did not rise as the gradient increased. DISCUSSION: Our results support the idea of considering the eight limbs functionally divided into two quadrupeds in series. The anterior was composed of the first two pairs of limbs, which have an explorative and steering purpose and the posterior was more involved in supporting the weight of the body. The mechanical work to move one unit of mass a unit distance is almost constant among the different species tested. However, spiders showed lower values than expected. Minimizing the mechanical work could help to limit metabolic energy expenditure that, in small animals, is relatively very high. However, energy recovery due to inverted pendulum mechanics only accounts for only a small fraction of the energy saved. Adhesive setae present in the tarsal, scopulae, and claw tufts could contribute in different ways during different moments of the step cycle, compensating for part of the energetic cost on gradients which could also help to maintain constant gait parameters.

Pendular energy transduction in the different phases of gait cycle in post-stroke subjects.

MAIN: To analyze spatiotemporal gait parameters and the body center of mass (CoM) energy transduction at self-selected speed walking in a group of older patients with stroke. METHODS: A cross-sectional study, fifteen subjects with 4.06 years post ̵stroke hemiparesis (eleven men and four women) and fifteen healthy subjects (four men and eleven women) participate in this study. Pendulum-like determining variables; Recovery (R) and Congruity percentage (%Cong) were analyzed in addition to immediate pendular re-conversion (Rint) during the phases in which the gait cycle is usually divided in clinical evaluations. RESULTS: Healthy subjects walked faster that stroke group (p = 0.001). %Cong was significantly higher in post-stroke respect to healthy subjects (p = 0.05). Rint showed significant differences between the groups for all phases (p = 0.05). The relation between speed and R was confirmed, for healthy (r = 0.67, p = 0.006) and post-stroke subjects (r = 0.851, p = 0.001), %Cong y Rint (r = -0.79, p = 0.001), (r = -0.93, p = 0.001) and periods of double support (r = -0.76, p = 0.001), (r = 0.69, p = 0.004) respectively. CONCLUSION: Alteration of pendular mechanism in subjects post-stroke is associated mainly with energy transduction; mechanical energy recovered during double support phases in healthy and post-stroke subjects follows a different trend, in post-stroke subjects, a longer duration of the double support is associated with less energy loss.

Construcción social del riesgo en el agro uruguayo: desafíos a la actividad sindical / Social construction of risk in the Uruguayan agricultural sector: challenges for union activity

RESUMEN Desde fines de la década de 1990, al igual que otros países de América Latina, Uruguay experimentó un "boom agrícola", el avance del sector agropecuario y la introducción de nuevas tecnologías, así como nuevas formas de producir y trabajar. Asimismo, a partir del año 2005 se observa un impulso de la sindicalización rural, asociado a los procesos de negociaciones colectivas y a la expansión de los derechos de los trabajadores a nivel nacional. Sin embargo, este proceso aún no ha logrado consolidar cambios significativos en las históricas condiciones laborales del trabajo rural. El trabajo analiza la construcción social del riesgo del trabajo asalariado rural, desde la perspectiva de dirigentes rurales, a partir de una aproximación cualitativa. En sus discursos aparecen elementos de naturalización y las dificultades persistentes en su labor para poder mejorar sus condiciones laborales, de modo de impactar en su salud y calidad de vida.

ABSTRACT Since the end of the 1990s, as in other Latin American countries, Uruguay has experienced an "agricultural boom," an advance in the agricultural sector and the introduction of new technologies as well as new ways of producing and working. In addition, since 2005, the country has seen a surge in rural unionization, associated with collective bargaining processes and the expansion of workers' rights at the national level. However, this process has not yet been able to consolidate significant changes in the historical working conditions of rural labor. This paper analyzes the social construction of the risk of rural wage labor from the perspective of rural leaders, based on a qualitative approach. In the workers' discourses appear elements of naturalization as well as persistent difficulties in their work to improve their working conditions, as a way of impacting their health and quality of life.

Aprovechamiento de energía, cinemática y estabilidad en la marcha de un paciente con amputación transfemoral sin abordaje de rehabilitación / Use of energy, kinematics and stability in gait of a patient with transfemoral amputation without rehabilitation approach

Resumen Introducción. Los pacientes con amputación de miembros inferiores presentan marcadas asimetrías en la marcha, las cuales pueden aumentar cuando no se cumple con un adecuado proceso de rehabilitación, comprometiendo los objetivos fundamentales de la marcha e incrementando factores de riesgo. Objetivo. Analizar el grado de aprovechamiento de energía mecánica, la estabilidad dinámica y las variables cinemáticas de interés clínico en la marcha de un paciente con amputación transfemoral que no realizó el proceso de rehabilitación. Materiales y métodos. Con base en una reconstrucción 3D, se cuantificaron valores angulares para cadera, rodilla y tobillo y se estimó el intercambio de energía mecánica y la estabilidad dinámica en tres velocidades de marcha diferentes. Resultados. Se observaron variaciones en los parámetros espacio-temporales con el cambio de la velocidad que no son consistentes con los encontrados en otros estudios de amputados. Los valores angulares, principalmente a nivel de rodilla y tobillo, presentan asimetrías que se pueden asociar con una disminución en el aprovechamiento de energía mecánica mientras aumenta la estabilidad en diferentes velocidades. Conclusión. El uso de prótesis en las condiciones en las que fue realizada la evaluación compromete la recuperación de energía mecánica en la marcha del paciente.

Abstract Introduction: Patients with lower limb amputation have marked gait asymmetries which may increase when an adequate rehabilitation process is not provided, compromising the fundamental objectives of gait and increasing risk factors. Objective: To analyze the degree of use of mechanical energy, dynamic stability and kinematic variables of clinical interest in the gait of a patient with transfemoral amputation who did not undergo a rehabilitation process. Materials and methods: Based on a 3D reconstruction, angular values for hip, knee and ankle were quantified and the mechanical energy exchange and dynamic stability were estimated at three different gait speeds. Results: Variations in spatiotemporal parameters were observed along with changes in speed, which are not consistent with the results obtained in other studies in amputees. The angular values, mainly of the knee and ankle, show asymmetries that can be associated with a decrease in the use of mechanical energy while increasing stability at different speeds. Conclusion: The use of prosthesis under the conditions in which the evaluation was performed compromises the recovery of the mechanical energy in the patient's gait.

[Social construction of risk in the Uruguayan agricultural sector: challenges for union activity]. / Construcción social del riesgo en el agro uruguayo: desafíos a la actividad sindical.

Since the end of the 1990s, as in other Latin American countries, Uruguay has experienced an "agricultural boom," an advance in the agricultural sector and the introduction of new technologies as well as new ways of producing and working. In addition, since 2005, the country has seen a surge in rural unionization, associated with collective bargaining processes and the expansion of workers' rights at the national level. However, this process has not yet been able to consolidate significant changes in the historical working conditions of rural labor. This paper analyzes the social construction of the risk of rural wage labor from the perspective of rural leaders, based on a qualitative approach. In the workers' discourses appear elements of naturalization as well as persistent difficulties in their work to improve their working conditions, as a way of impacting their health and quality of life.

Desde fines de la década de 1990, al igual que otros países de América Latina, Uruguay experimentó un "boom agrícola", el avance del sector agropecuario y la introducción de nuevas tecnologías, así como nuevas formas de producir y trabajar. Asimismo, a partir del año 2005 se observa un impulso de la sindicalización rural, asociado a los procesos de negociaciones colectivas y a la expansión de los derechos de los trabajadores a nivel nacional. Sin embargo, este proceso aún no ha logrado consolidar cambios significativos en las históricas condiciones laborales del trabajo rural. El trabajo analiza la construcción social del riesgo del trabajo asalariado rural, desde la perspectiva de dirigentes rurales, a partir de una aproximación cualitativa. En sus discursos aparecen elementos de naturalización y las dificultades persistentes en su labor para poder mejorar sus condiciones laborales, de modo de impactar en su salud y calidad de vida.

Evaluación de variables espacio-temporales y transferencia de energía mecánica en la marcha de un paciente con ACV: estudio piloto / Space-time assessment and mechanical energy transfer during gait in a patient with a CVA: a pilot study

Introducción: los individuos con accidente cerebrovascular (ACV) presentan una marcha asimétrica. Para su recuperación es importante conocer los valores angulares de cadera, rodilla y tobillo en diferentes eventos, pero esto no permite determinar en qué grado se cumple el objetivo de desplazarse minimizando el gasto de energía. El estudio de la mecánica del centro de masas durante la marcha puede contribuir en este último aspecto; este aporte, discutido y valorado en conjunto con los valores angulares, permitiría entender más sobre las complejidades de la marcha luego de un ACV. Objetivo: aplicar una herramienta para evaluar el aprovechamiento de energía mecánica en la marcha de pacientes con ACV y discutir los resultados en función de los valores angulares observados para miembros inferiores. Material y método: se realizó un estudio de reconstrucción tridimensional del movimiento utilizando un equipo Vicon Motion Systems en un individuo con ACV y uno sano. Se evaluaron los ángulos cadera, rodilla y tobillo en el plano sagital durante diferentes eventos de la marcha y se estimó el intercambio energético a través del cálculo de Energy recovery (R). Resultados: el individuo con ACV presentó un patrón de marcha donde predomina la flexión de ambos miembros inferiores durante la fase de apoyo y el R fue marcadamente menor (33%) que en el individuo control (56%). Estos resultados sugieren una asociación entre los valores angulares y los energéticos implicados en el cálculo de R. El abordaje tiene potencial utilidad clínica en el análisis de la marcha de sujetos con ACV.

Introduction: individuals who suffered a CVA present an asymmetrical gait. It is important to learn about the angles in the hip, knee and ankle during different events in order to contribute to their recovery, although this does not allow the calculation of the degree of fulfillment in stepping with minimum energy output. The study of the center of mass mechanics during gait may contribute in the latter. This contribution, once discussed and assessed, together with the angle values would enable a better understanding of the complexities of gait following a CVA. Objective: to apply a tool to assess the best use of mechanical energy in the gait of CVA patients, and to discuss results considering angle values observed in lower limbs. Method: we conducted a three-dimensional reconstruction study of movement with a Vicon Motion Systems equipment in a CVA patient and a healthy individual. Angles in the hip, knee and ankle were assessed in the sagittal plane during different gait events, and the energy exchange was estimates by means of Energy recovery (R) calculation. Results: The CVA patient presented a gait pattern where flexion of both lower limbs prevails during the contact phase and R was significantly lower (33%) than that of the control individual (56%). These results suggest there is an association between angle values and energy in the calculation of R. The approach has potential for clinical usefulness in the analysis of gait in individuals following a CVA.

Introdução: os indivíduos com acidente vascular cerebral (AVC) apresentam uma marcha assimétrica. Para sua recuperação é importante conhecer os valores angulares de quadril, joelho e tornozelo em diferentes eventos, porém isto não permite determinar em que grau o objetivo de deslocar-se minimizando o gasto de energia é atingido. O estudo da mecânica do centro de massas durante a marcha pode contribuir neste último aspecto; essa informação, discutida e avaliada juntamente com os valores angulares, permitiria entender melhor as características da marcha depois de um AVC. Objetivo: aplicar uma ferramenta para avaliar o aproveitamento de energia mecânica na marcha de pacientes com AVC e discutir os resultados em função dos valores angulares observados para membros inferiores. Material e método: realizou-se um estudo de reconstrução tridimensional do movimento utilizando um equipamento Vicon Motion Systems em um indivíduo com AVC e em outro sadio. Os ângulos quadril, joelho e tornozelo no plano sagital durante diferentes eventos da marcha foram avaliados e o intercambio energético foi estimado usando o cálculo de Energy recovery (R). Resultados: O indivíduo com AVC apresentou um padrão de marcha no qual predomina a flexão de ambos membros inferiores durante a fase de apoio e o R foi muito menor (33%) que no individuo controle (56%). Estes resultados sugerem uma associação entre os valores angulares e os energéticos implicados no cálculo de R. Esta abordagem tem uma potencial utilidade clínica na análise da marcha de sujeitos com tiveram um AVC.