Ergonomia en actividades académicas desde casa

Introducción: A consecuencia de la emergencia sanitaria por el virus SARS-CoV2, las actividades académicas migraron de forma repentina a un entorno de trabajo remoto; esto provocó que los hogares de todo el mundo se convirtieran en el asentamiento urgente de las estaciones de trabajo académico. La ergonomia como disciplina científica cobra relevancia al ser un aliado subsanador para mitigar los riesgos asociados con la aparición de lesiones musculoesqueléticas. De acuerdo con la memoria estadística del Instituto Mexicano de Seguridad Social, IMSS1, en el primer año de pandemia de COVID-19 se registraron 30 860 atenciones por lesiones en la región de manos y muñecas, 9696 en la zona de cabeza y cuello, 6251 dorsopatías y 1673 atenciones por astenopia a jóvenes de entre 18 a 29 años que desarrollaban actividades escolares. Objetivo: En este sentido, se aborda la presente investigación para conocer la composición de los espacios de trabajo académico en casa y analizar si existen factores o elementos que incidan en el riesgo de lesiones musculoesqueléticas en los estudiantes del nivel superior. Metodología: A través de un modelo de ecuaciones estructurales que cuenta con el constructo latente de las posibles lesiones (PL) en manos, espalda, piernas, cabeza, vista, oído, agotamiento físico y la respiración, las variables observables se atribuyen a los espacios utilizados para las actividades académicas en casa, muebles y equipos, Condiciones y Medio Ambiente (CyMAT). Resultados y discusión: Se encontró que un mal diseño de la estación de trabajo académico en casa, aunado a la utilización inadecuada de los muebles y equipos, aumenta la posibilidad de presentar síntomas asociados con las LMEs y, por tanto, daños en la salud del estudiante. Conclusión: La mediación de las estaciones de trabajo a través de la implementación de elementos ergonómicos mejora de forma sustancial la calidad de trabajo académico en casa, y hace evidente la importancia de la ergonomía como disciplina científica.

Introduction: As a result of the health emergency of the SARS-CoV2 virus, academic activities suddenly migrated to a remote work environment, causing homes around the world to become the urgent settlement of academic workstations. Ergonomics as a scientific discipline becomes relevant as it is a healing ally to mitigate the risks associated with the appearance of musculoskeletal injuries. According to the statistical report of the Mexican Institute of Social Security, IMSS1, in the first year of the COVID 19 pandemic, 30,860 care for injuries in the hands and wrists region, 9,696 in the head and neck area, 6,251 dorsopathies and 1,673 care for asthenopia were registered to young people between 18 and 29 years old who develop school activities. Objective: In this sense, this research is addressed to know the composition of academic workspaces at home and analyze if some factors or elements affect the risk of musculoskeletal injuries in students of the higher level. Methodology: Through a structural equations model that has the latent construct of possible injuries (PL) in the hands, back, legs, head, eyesight, hearing, physical exhaustion, and breathing; the observable variables are attributed to the spaces used for academic activities at home, furniture and equipment, conditions and environment (CyMAT) Results and discussion: It is explored that a bad design of the academic workstation at home coupled with the inappropriate use of furniture and equipment increases the possibility of presenting symptoms associated with SCI and therefore, damage to the student's health. Conclusion: The mediation of workstations through the implementation of ergonomic elements substantially improves the quality of academic work at home, making evident the importance of ergonomics as a scientific discipline

Generalisation decrement and not overshadowing by associative competition among pairs of landmarks in a navigation task with humans.

In three experiments, a virtual preparation for humans of the Morris water task (VMWT) was used. Experiment 1 established that four landmarks were of similar salience. Then, in Experiments 2 and 3, participants were trained to locate a hidden platform in the presence or either two or four of the previous landmarks. In Experiment 2, one pair of groups was trained with four visual landmarks spaced at equal intervals around the edge of the pool, while a second pair was trained with two landmarks only, either relatively close to or far from the hidden platform. After training, a reciprocal overshadowing effect was found: on a test without the platform with two landmarks only (either close to or far from the platform position), the participants trained with four landmarks spent less time in the platform quadrant than those trained with only two. Finally, Experiment 3 showed that at least participants trained with two landmarks relatively close to the platform and then tested with four also performed worse on test than those trained and tested with two close landmarks only. This result suggests that generalisation decrement, rather than associative competition, could provide a sufficient explanation for the overshadowing observed in Experiment 2 in the proximal groups. The present set of experiments extend, although only partially, the generalisation decrement results documented in rats to human participants.

Anti-oxidative effects produced by environmental enrichment in the hippocampus and cerebral cortex of male and female rats.

Both physical and intellectual activity may reduce the incidence of neurodegenerative disorders. There is evidence that environmental enrichment (EE) can induce profound behavioral, neurochemical and neuroanatomical changes, thus producing lasting improvements in memory and learning tasks. In this study we evaluated the anti-oxidative effects produced by EE in the hippocampus and the cerebral cortex of male and female rats. The animals had been reared in either EE or control conditions. The parameters studied were: thiobarbituric acid reactive substances (TBARS), protein oxidation, total radical antioxidant parameter, catalase, superoxide dismutase and superoxide anion activity. The results showed that our EE protocol reduced markers of oxidative stress in the hippocampus and in the cerebral cortex. Overall, the measures taken in the two cerebral regions revealed that EE rats showed higher values for antioxidant measures and lower values for oxidative stress parameters than control animals. More importantly, a consistent sex difference was found, indicating that in female rats the hippocampus and cerebral cortex are plastic brain regions receptive to external stimulation such as EE. Although EE males have higher levels for antioxidant capacity, catalase and SOD, it is likely that females do not need to activate all the antioxidant defenses since they have a greater capacity to assimilate external stimuli. This is suggested by the similarity of protein oxidation and TBARS levels in hippocampus in both sexes, and the even lower levels of protein oxidation and superoxide anion activity in the cerebral cortex in EE females.

What makes a landmark effective? Sex differences in a navigation task.

In Experiment 1, two groups of female rats were trained in a triangular pool to find a hidden platform whose location was defined in terms of a single a landmark, a cylinder outside the pool. For one group, the landmark had only a single pattern (i.e., it looked the same when approached from any direction), while for the other, the landmark contained four different patterns (i.e., it looked different when approached from different directions). The first group learned to swim to the platform more rapidly than the second. Experiment 2 confirmed this difference when female rats were trained in a circular pool but found that male rats learned equally rapidly (and as rapidly as females trained with the single-pattern landmark) with both landmarks. This second finding was confirmed in Experiment 3. Finally, in Experiment 4a and 4b, male and female rats were trained either with the same, single-pattern landmark on all trials or with a different landmark each day. Males learned equally rapidly (and as rapidly as females trained with the unchanged landmark) whether the landmark changed or not. We conclude that male and female rats learn rather different things about the landmark that signals the location of the platform.

Landmark vs. geometry learning: explaining female rats' selective preference for a landmark / Aprendizaje basado en un punto de referencia vs.aprendizaje de la geometría: explicando la preferencia selectiva de las ratas hembra por un punto de referencia

Rats were trained in a triangular-shaped pool to find a hidden platform, whose location was defined in terms of two sources of information, a landmark outside the pool and a particular corner of the pool. Subsequent test trials without the platform pitted these two sources of information against one another. In Experiment 1 this test revealed a clear, although selective, sex difference. As in previous experiments, females spent more time in an area of the pool that corresponded to the landmark, but here only when it was a cone but not when it was a pyramid. Males, on the other hand, always spent more time in the distinctive corner of the pool. Experiments 2 and 3 were only with female rats. In Experiment 2 two identical shaped cylinders were used as landmark cues (one plain white and the other vertically patterned with four different patterns). The results of the preference test revealed that only the females trained and tested with the plain cylinder spent more time in the area of the pool that corresponded to the landmark than in the distinctive corner of the pool. Finally, Experiment 3 replicated the results of Experiment 2 while eliminating an alternative explanation in terms of differential contrast between the two cylinders and the black curtain (AU)

Se entrenó a unas ratas en una piscina con forma triangular a que encontrasen una plataforma oculta, cuya ubicación estaba definida en base a dos fuentes de información, un punto de referencia y una parte de la piscina con una forma distintiva. Ensayos de prueba posteriores, sin la plataforma, enfrentaron la forma y el punto de referencia. En el Experimento 1 esta prueba reveló una diferencia de sexo clara, aunque selectiva. Como en experimentos anteriores, las hembras pasaron más tiempo en el área de la piscina que se correspondía con el punto de referencia, aunque sólo cuando este era un cono no cuando era una pirámide. Por otro lado, los machos siempre pasaron más tiempo en el área de la piscina que se correspondía con la forma distintiva. Los Experimentos 2 y 3 se llevaron a cabo sólo con ratas hembra. En el Experimento 2 se emplearon como puntos de referencia dos formas cilíndricas idénticas (una de color blanco y la otra verticalmente dividida en cuatro segmentos con trama diferente). Los resultados de las pruebas de preferencia revelaron que solamente las hembras entrenadas y puestas a prueba con el cilindro blanco pasaron más tiempo en el área de la piscina que se correspondía con el punto de referencia que en el área de la piscina que se correspondía con la forma distintiva. Por último, el Experimento 3 replicó los resultados de los Experimentos 1 y 2 eliminando una explicación alternativa basada en el contraste diferente de los dos cilindros respecto a las cortinas negras (AU)

Do hormonal changes that appear at the onset of puberty determine the strategies used by female rats when solving a navigation task?

The present set of experiments evaluated the possibility that the hormonal changes that appear at the onset of puberty might influence the strategies used by female rats to solve a spatial navigation task. In each experiment, rats were trained in a triangular shaped pool to find a hidden platform which maintained a constant relationship with two sources of information, one individual landmark and one corner of the pool with a distinctive geometry. Then, three test trials were conducted without the platform in counterbalanced order. In one, both the geometry and the landmark were simultaneously presented, although in different spatial positions, in order to measure the rats' preferences. In the remaining test trials what the rats had learned about the two sources of information was measured by presenting them individually. Experiment 1, with 60-day old rats, revealed a clear sex difference, thus replicating a previous finding (Rodríguez et al., 2010): females spent more time in an area of the pool that corresponded to the landmark, whereas males spent more time in the distinctive corner of the pool even though the remaining tests revealed that both sexes had learned about the two sources of information. In Experiment 2, 30-day old female rats, unlike adults, preferred to solve the task using the geometry information rather than the landmark (although juvenile males behaved in exactly the same way as adults). Experiment 3 directly compared the performance of 90- and 30-day old females and found that while the adult females preferred to solve the task using the landmark, the reverse was true in juvenile females. Experiment 4 compared ovariectomized and sham operated females and found that while sham operated females preferred to solve the task using the landmark, the reverse was true in ovariectomized females. Finally, Experiment 5 directly compared adult males and females, juvenile males and females, and ovariectomized females and found that adult males, juvenile males and females, and ovariectomized females did not differ among them in their preferred cue, but they all differed from adult females.

Generalization decrement and not overshadowing by associative competition among pairs of landmarks in a navigation task.

When they are trained in a Morris water maze to find a hidden platform, whose location is defined by a number of equally spaced visual landmarks round the circumference of the pool, rats are equally able to find the platform when tested with any two of the landmarks (Prados, & Trobalon, 1998; Rodrigo, Chamizo, McLaren, & Mackintosh, 1997). This suggests that none of the landmarks was completely overshadowed by any of the others. In Experiment 1 one pair of groups was trained with four equally salient visual landmarks spaced at equal intervals around the edge of the pool, while a second pair was trained with two landmarks only, either relatively close to or far from the hidden platform. After extensive training, both male and female rats showed a reciprocal overshadowing effect: on a test with two landmarks only (either close to or far from the platform), rats trained with four landmarks spent less time in the platform quadrant than those trained with only two. Experiment 2 showed that animals trained with two landmarks and then tested with four also performed worse on test than those trained and tested with two landmarks only. This suggests that generalization decrement, rather than associative competition, provides a sufficient explanation for the overshadowing observed in Experiment 1. Experiment 3 provided a within-experiment replication of the results of Experiments 1 and 2. Finally, Experiment 4 showed that rats trained with a configuration of two landmarks learn their identity.

Overshadowing and blocking between landmark learning and shape learning: the importance of sex differences.

Rats were trained in a triangular-shaped pool to find a hidden platform that maintained a constant relationship with two sources of information, an individual landmark and one part of the pool with a distinctive shape. In Experiment 1, shape learning overshadowed landmark learning but landmark learning did not overshadow shape learning in males, while landmark learning overshadowed shape learning but shape learning did not overshadow landmark learning in females. In Experiment 2, rats were pretrained either with the single landmark relevant or with the shape relevant, in the absence of the alternative cue. Final test trials, without the platform, revealed reciprocal blocking only in females; in males, shape learning blocked landmark learning, but not viceversa (Experiment 2a). In Experiment 2b, male rats received a longer pretraining with the single landmark relevant, and now landmark learning blocked shape learning. The results thus confirm the claim that males and females partially use different types of spatial information when solving spatial tasks. These results also agree with the suggestion that shape learning interacts with landmark learning in much the same way as does learning about any pair of stimuli in a Pavlovian conditioning experiment.

Landmark learning in a navigation task is not affected by the female rats’ estrus cycle

En dos experimentos en piscina circular se entrenó a unas ratas a encontrar una plataforma invisible que estaba localizada siempre en el mismo lugar en relación a una configuración de dos puntos de referencia (X e Y), que se encontraban relativamente lejos y equidistantes de la plataforma. El entrenamiento se llevó a cabo durante días consecutivos (Experimento 1) o cada 4 días (Experimento 2). Ensayos de prueba posteriores, sin la plataforma, mostraron que las ratas preferían buscar en el cuadrante correcto de la piscina. En el Experimento 1 la ejecución en el ensayo de prueba fue idéntica en dos grupos de hembras, uno puesto a prueba con altos niveles hormonales (es decir, en la fase de proestro) y el otro con bajos niveles hormonales (concretamente, en la fase de estro, metaestro o diestro); además, ambos grupos de hembras difirieron de un tercer grupo de machos (los machos ejecutaron mejor la tarea que las hembras). El Experimento 2 replicó los datos anteriores obtenidos por las hembras, con un procedimiento mejorado. El experimento comparó la ejecución de dos grupos de hembras que fueron entrenados y puestos a prueba siempre en la misma fase del ciclo estral, un grupo en la fase de proestro y el segundo en la fase de estro. La implicación de estos resultados es que el ciclo estral tiene muy poco impacto en el aprendizaje basado en puntos de referencia en una tarea de navegación espacial(AU)

In two experiments rats were required to escape from a circular pool by swimming to an invisible platform that was located in the same place relative to one configuration of two landmarks (X and Y). The two landmarks were placed relatively far and equidistant from the hidden platform. Training could be either on consecutive days (Experiment 1) or every fourth day (Experiment 2). Subsequent test trials, without the platform, revealed a preference for searching in the correct quadrant of the pool. In Experiment 1 such a test performance was identical in two groups of females, one tested with high hormonal levels (i.e., in the proestrus phase) and the second one tested with low hormonal levels (i.e., either in the estrus, metaestrus or diestrus phase); in addition, these two groups differed from a third group of male rats (i.e., males had a better performance than females). Experiment 2 replicated the females’ previous results with a better procedure. The experiment compared the performance of two groups of female rats which were both trained and tested always in the same estrus phase, one group in the proestrus phase, and the second group in the estrus phase. The implication of these results is that the estrus cycle has little impact on the performance of female rats when landmark learning in a navigation task(AU)

Sex differences in the strategies used by rats to solve a navigation task.

Rats were trained in a triangular-shaped pool to find a hidden platform, whose location was defined in terms of two sources of information, a landmark outside the pool and a particular corner of the pool. Subsequent test trials without the platform pitted these two sources of information against one another. This test revealed a clear sex difference. Females spent more time in an area of the pool that corresponded to the landmark, whereas males spent more time in the distinctive corner of the pool even though further tests revealed that both sexes had learned about the two sources of information by presenting cues individually. The results agree with the claim that males and females use different types of information in spatial navigation.

Trauma por bombas y explosiones: daño cerebral asociado / Trauma due to bombs and explotions: associated cerebral damage

Este artículo revisa la bibliografía actualizada del trauma por bombas y explosiones, y hace hincapié en el daño cerebral asociado.