Asociación entre la postura en sentado y el dolor de espalda en estudiantes universitarios

Introduccion: El dolor de espalda es un problema importante de salud pública, su prevalencia en estudiantes universitarios está entre el 30 al 70%; su asociacion con la postura sentada en trabajadores ha sido reportada, pero en poblacion universitaria su estudio es limitado. Objetivo: Evaluar la asociación entre la postura en sentado con el dolor de espalda en estudiantes universitarios. Métodos: Estudio de corte transversal. Variables explicatorias: características sociodemográficas, iluminación del salón de clase, postura en sedente y tipo de silla. Variables de salida: dolor de cuello o espalda el día de la encuesta, agudo y crónico. Modelos de regresión log-binomial estimaron las razones de prevalencia (RP) y sus IC95%. Resultados: Participaron 516 estudiantes de la facultad de salud, edad 21,3±2,6 años, 69,2% mujeres, 29,5% estaban en tercer año; y el 72,8% pertenecía a los estratos socioeconómicos 3 y 4, con un 18,4% de los estudiantes, que además de estudiar desarrollaban actividades laborales. El 87,8% de los salones de clase presentan iluminación adecuada. La postura en sedente con espalda redondeada, pies en otra superficie y pierna cruzada se asoció con dolor de cuello el día de la encuesta (RP: 2,84), agudo (RP: 2,41) y crónico (RP: 4,13). Otra postura sentada con espalda redondeada y una pierna cruzada se asoció con dolor de espalda el día de la encuesta (RP: 1,81) y agudo (RP: 2,0). El tiempo en computador se asoció con las variables de salida (RP 1.01 - 2,08). Conclusión: Los resultados apoyan la implementación de políticas y proyectos institucionales dirigidos a prevenir y controlar el dolor de espalda en universitarios.Introduction: Back pain is a significant public health problem, its prevalence among college students is high, 30 - 70%; Its association with the sitting position in workers has been reported, but its study in university populations is limited. Objective: To evaluate the association between sitting posture with back pain among college students. Methods: Cross-sectional study. Explanatory variables: sociodemographic characteristics, adequate lighting in the classroom, sitting posture and type of chair. Outcome variables: neck or back pain the day of the survey, acute and chronic. Logbinomial regression models estimated prevalence ratios (PR) and their 95% CI. Results: 516 students from health deparment, age 21.3 ± 2.6 years, 69.2% women, 29,5% were in third year; 72,8% belong to middle socioeconomical level (3 and 4); and 18,4% of the students had an additional working activity. 87,8% of the classrooms had adequate lighting. Sitting posture with rounded back, feet supported on another chair and crossed legs was associated with neck pain the day of the survey (PR: 2.84), acute (PR: 2.41) and chronic (PR: 4.13). Other sitting posture with rounded back and crossed leg was associated with back pain the day of the survey (PR: 1.81) and acute (PR: 2.0). The screen time at the computer was associated with the outcome variables (PR 1.01 - 2.08). Conclusion: The results support the implementation of policies and institutional projects in order to prevent and control the back pain in college students.&nbsp

Asociación entre la postura en sentado y el dolor de espalda en estudiantes universitarios

Introduccion: El dolor de espalda es un problema importante de salud pública, su prevalencia en estudiantes universitarios está entre el 30 al 70%; su asociacion con la postura sentada en trabajadores ha sido reportada, pero en poblacion universitaria su estudio es limitado. Objetivo: Evaluar la asociación entre la postura en sentado con el dolor de espalda en estudiantes universitarios. Métodos: Estudio de corte transversal. Variables explicatorias: características sociodemográficas, iluminación del salón de clase, postura en sedente y tipo de silla. Variables de salida: dolor de cuello o espalda el día de la encuesta, agudo y crónico. Modelos de regresión log-binomial estimaron las razones de prevalencia (RP) y sus IC95%. Resultados: Participaron 516 estudiantes de la facultad de salud, edad 21,3±2,6 años, 69,2% mujeres, 29,5% estaban en tercer año; y el 72,8% pertenecía a los estratos socioeconómicos 3 y 4, con un 18,4% de los estudiantes, que además de estudiar desarrollaban actividades laborales. El 87,8% de los salones de clase presentan iluminación adecuada. La postura en sedente con espalda redondeada, pies en otra superficie y pierna cruzada se asoció con dolor de cuello el día de la encuesta (RP: 2,84), agudo (RP: 2,41) y crónico (RP: 4,13). Otra postura sentada con espalda redondeada y una pierna cruzada se asoció con dolor de espalda el día de la encuesta (RP: 1,81) y agudo (RP: 2,0). El tiempo en computador se asoció con las variables de salida (RP 1.01 - 2,08). Conclusión: Los resultados apoyan la implementación de políticas y proyectos institucionales dirigidos a prevenir y controlar el dolor de espalda en universitarios.Introduction: Back pain is a significant public health problem, its prevalence among college students is high, 30 - 70%; Its association with the sitting position in workers has been reported, but its study in university populations is limited. Objective: To evaluate the association between sitting posture with back pain among college students. Methods: Cross-sectional study. Explanatory variables: sociodemographic characteristics, adequate lighting in the classroom, sitting posture and type of chair. Outcome variables: neck or back pain the day of the survey, acute and chronic. Logbinomial regression models estimated prevalence ratios (PR) and their 95% CI. Results: 516 students from health deparment, age 21.3 ± 2.6 years, 69.2% women, 29,5% were in third year; 72,8% belong to middle socioeconomical level (3 and 4); and 18,4% of the students had an additional working activity. 87,8% of the classrooms had adequate lighting. Sitting posture with rounded back, feet supported on another chair and crossed legs was associated with neck pain the day of the survey (PR: 2.84), acute (PR: 2.41) and chronic (PR: 4.13). Other sitting posture with rounded back and crossed leg was associated with back pain the day of the survey (PR: 1.81) and acute (PR: 2.0). The screen time at the computer was associated with the outcome variables (PR 1.01 - 2.08). Conclusion: The results support the implementation of policies and institutional projects in order to prevent and control the back pain in college students.&nbsp

Height-diameter allometry of tropical forest trees

Copyright © 2011 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/8/1081/2011/bg-8-1081-2011.html doi:10.5194/bg-8-1081-2011Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Height-diameter allometry of tropical forest trees

Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account. © 2011 Author(s)

Amazon tree dominance across forest strata

The forests of Amazonia are among the most biodiverse plant communities on Earth. Given the immediate threats posed by climate and land-use change, an improved understanding of how this extraordinary biodiversity is spatially organized is urgently required to develop effective conservation strategies. Most Amazonian tree species are extremely rare but a few are common across the region. Indeed, just 227 ‘hyperdominant’ species account for >50% of all individuals >10 cm diameter at 1.3 m in height. Yet, the degree to which the phenomenon of hyperdominance is sensitive to tree size, the extent to which the composition of dominant species changes with size class and how evolutionary history constrains tree hyperdominance, all remain unknown. Here, we use a large floristic dataset to show that, while hyperdominance is a universal phenomenon across forest strata, different species dominate the forest understory, midstory and canopy. We further find that, although species belonging to a range of phylogenetically dispersed lineages have become hyperdominant in small size classes, hyperdominants in large size classes are restricted to a few lineages. Our results demonstrate that it is essential to consider all forest strata to understand regional patterns of dominance and composition in Amazonia. More generally, through the lens of 654 hyperdominant species, we outline a tractable pathway for understanding the functioning of half of Amazonian forests across vertical strata and geographical locations