70 research outputs found
Do you have what it takes? An analysis of the factors associated with the intention to choose a surgical career among medical undergraduates
Resumen Introducción Los cambios en la práctica profesional han transformado la intención de los estudiantes de medicina de optar por una carrera en cirugía. Objetivo Evaluar los factores asociados con esta intención en un contexto de acelerada dinámica educativa y sanitaria. Materiales y Método Evaluamos la intención de los estudiantes de diez facultades de medicina en Colombia, y los factores asociados, mediante un cuestionario (escala de Likert) desarrollado a partir de la revisión de la literatura. Identificamos la asociación entre los factores y la intención mediante un análisis de regresión lineal. Los resultados de la regresión se presentan mediante coeficientes ? (p < 0,05). Resultados Un total de 252 estudiantes (65,87% mujeres) fueron incluidos en el análisis. El promedio de la intención fue 3,15 ± 1,34 (1-5). Los factores significativamente asociados fueron: identificación con el estilo de vida quirúrgico (? = 0,25); identificación con modelos (? = 0,18); atributos personales (? = 0,25) e identificación con la práctica profesional del cirujano (? = 0,16). No encontramos asociación significativa con el género (mujeres en la especialidad), prestigio, dinámica del posgrado ni recompensa futura. Conclusión Existe una intención moderada de elegir una carrera de cirugía entre estudiantes de medicina colombianos. Optar por esta carrera requiere atributos personales, modelos e identificación con el estilo de vida y práctica profesional del cirujano. Se requieren estudios cualitativos que exploren en profundidad estos resultados e intervenciones focalizadas a estimular esta intención entre los estudiantes.Introduction The changes in the professional practice have transformed the intention of medical students to choose a surgical career. Aim Evaluate the factors associated with this intention in a context of accelerated educational and health dynamics. Materials and Method We evaluated the intention of the students of ten medical schools in Colombia, and the associated factors, through a questionnaire (Likert scale) settled from a literature review. We identify the association between the factors and the intention by using linear regression analysis. The results of the regression are presented by ? coefficients (p < 0.05). Results A total of 252 students (65.87% women) were included in the analysis. The average of the intention was 3.15 ± 1.34 (1-5). The factors significantly associated were: identification with the surgical lifestyle (? = 0.25); identification with models (? = 0.18); personal attributes (? = 0.25) and identification with the professional practice of the surgeon (? = 0.16). We did not find significant associations with gender (women in the specialty), prestige, postgraduate dynamics and future rewards. Conclusion There is a moderate intention to choose a career in surgery among Colombian medical undergraduates. Choosing this career requires personal attributes, models and identification with the lifestyle and professional practice of the surgeon. Further qualitative studies are necessary to explore these results in depth, as well as interventions to stimulate this intention among students
Deltamethrin resistance in Aedes aegypti results in treatment failure in Merida, Mexico
The operational impact of deltamethrin resistance on the efficacy of indoor insecticide applications to control Aedes aegypti was evaluated in Merida, Mexico. A randomized controlled trial quantified the efficacy of indoor residual spraying (IRS) against adult Ae. aegypti in houses treated with either deltamethrin (to which local Ae. aegypti expressed a high degree of resistance) or bendiocarb (to which local Ae. aegypti were fully susceptible) as compared to untreated control houses. All adult Ae. aegypti infestation indices during 3 months post-spraying were significantly lower in houses treated with bendiocarb compared to untreated houses (odds ratio < 0.75; incidence rate ratio < 0.65) whereas no statistically significant difference was detected between the untreated and the deltamethrin-treated houses. On average, bendiocarb spraying reduced Ae. aegypti abundance by 60% during a 3-month period. Results demonstrate that vector control efficacy can be significantly compromised when the insecticide resistance status of Ae. aegypti populations is not taken into consideration
Metabolic synergies in the biotransformation of organic and metallic toxic compounds by a saprotrophic soil fungus
The saprotrophic fungus Penicillium griseofulvum was chosen as model organism to study responses to a mixture of hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, γ-HCH, δ-HCH) and of potentially toxic metals (vanadium, lead) in solid and liquid media. The P. griseofulvum FBL 500 strain was isolated from polluted soil containing high concentrations of HCH isomers and potentially toxic elements (Pb, V). Experiments were performed in order to analyse the tolerance/resistance of this fungus to xenobiotics, and to shed further light on fungal potential in inorganic and organic biotransformations. The aim was to examine the ecological and bioremedial potential of this fungus verifying the presence of mechanisms that allow it to transform HCH isomers and metals under different, extreme, test conditions. To our knowledge, this work is the first to provide evidence on the biotransformation of HCH mixtures, in combination with toxic metals, by a saprotrophic non-white-rot fungus and on the metabolic synergies involved
Phytostabilization of mine tailings using compost-assisted direct planting: Translating greenhouse results to the field
Standard practice in reclamation of mine tailings is the emplacement of a 15 to 90 cm soil/gravel/rock cap which is then hydro-seeded. In this study we investigate compost-assisted direct planting phytostabilization technology as an alternative to standard cap and plant practices. In phytostabilization the goal is to establish a vegetative cap using native plants that stabilize metals in the root zone with little to no shoot accumulation. The study site is a barren 62-hectare tailings pile characterized by extremely acidic pH as well as lead, arsenic, and zinc each exceeding 2000 mg kg(-1). The study objective is to evaluate whether successful greenhouse phytostabilization results are scalable to the field. In May 2010, a 0.27 ha study area was established on the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site with six irrigated treatments; tailings amended with 10, 15, or 20% (w/w) compost seeded with amix of native plants (buffalo grass, arizona fescue, quailbush, mountain mahogany, mesquite, and catclaw acacia) and controls including composted (15 and 20%) unseeded treatments and an uncomposted unseeded treatment. Canopy cover ranging from 21 to 61% developed after 41 months in the compost-amended planted treatments, a canopy cover similar to that found in the surrounding region. No plants grew on unamended tailings. Neutrophilic heterotrophic bacterial counts were 1.5 to 4 orders of magnitude higher after 41 months in planted versus unamended control plots. Shoot tissue accumulation of various metal(loids) was at or below Domestic Animal Toxicity Limits, with some plant specific exceptions in treatments receiving less compost. Parameters including % canopy cover, neutrophilic heterotrophic bacteria counts, and shoot uptake of metal(loids) are promising criteria to use in evaluating reclamation success. In summary, compost amendment and seeding, guided by preliminary greenhouse studies, allowed plant establishment and sustained growth over 4 years demonstrating feasibility for this phytostabilization technology. (C) 2016 Elsevier B.V. All rights reserved.NIEHS Superfund Research Program [2 P42 ES04940]24 month embargo; published online: 13 May 2016This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Bacterial community dynamics in full-scale activated sludge bioreactors: operational and ecological factors driving community assembly and performance.
The assembling of bacterial communities in conventional activated sludge (CAS) bioreactors was thought, until recently, to be chaotic and mostly unpredictable. Studies done over the last decade have shown that specific, and often, predictable random and non-random factors could be responsible for that process. These studies have also motivated a "structure-function" paradigm that is yet to be resolved. Thus, elucidating the factors that affect community assembly in the bioreactors is necessary for predicting fluctuations in community structure and function. For this study activated sludge samples were collected during a one-year period from two geographically distant CAS bioreactors of different size. Combining community fingerprinting analysis and operational parameters data with a robust statistical analysis, we aimed to identify relevant links between system performance and bacterial community diversity and dynamics. In addition to revealing a significant β-diversity between the bioreactors' communities, results showed that the largest bioreactor had a less dynamic but more efficient and diverse bacterial community throughout the study. The statistical analysis also suggests that deterministic factors, as opposed to stochastic factors, may have a bigger impact on the community structure in the largest bioreactor. Furthermore, the community seems to rely mainly on mechanisms of resistance and functional redundancy to maintain functional stability. We suggest that the ecological theories behind the Island Biogeography model and the species-area relationship were appropriate to predict the assembly of bacterial communities in these CAS bioreactors. These results are of great importance for engineers and ecologists as they reveal critical aspects of CAS systems that could be applied towards improving bioreactor design and operation
Treatment impacts on temporal microbial community dynamics during phytostabilization of acid-generating mine tailings in semiarid regions
Direct revegetation, or phytostabilization, is a containment strategy for contaminant metals associated with mine tailings in semiarid regions. The weathering of sulfide ore-derived tailings frequently drives acidification that inhibits plant establishment resulting in materials prone to wind and water dispersal. The specific objective of this study was to associate pyritic mine waste acidification, characterized through pore-water chemistry analysis, with dynamic changes in microbial community diversity and phylogenetic composition, and to evaluate the influence of different treatment strategies on the control of acidification dynamics. Samples were collected from a highly instrumented one-year mesocosm study that included the following treatments: 1) unamended tailings control; 2) tailings amended with 15% compost; and 3) the 15% compost-amended tailings planted with Atriplex lentiformis. Tailings samples were collected at 0, 3, 6 and 12months and pore water chemistry was monitored as an indicator of acidification and weathering processes. Results confirmed that the acidification process for pyritic mine tailings is associated with a temporal progression of bacterial and archaeal phylotypes from pH sensitive Thiobacillus and Thiomonas to communities dominated by Leptospirillum and Ferroplasma. Pore-water chemistry indicated that weathering rates were highest when Leptospirillum was most abundant. The planted treatment was most successful in disrupting the successional evolution of the Fe/S-oxidizing community. Plant establishment stimulated growth of plant-growth-promoting heterotrophic phylotypes and controlled the proliferation of lithoautotrophic Fe/S-oxidizers. The results suggest the potential for eco-engineering a microbial inoculum to stimulate plant establishment and inhibit proliferation of the most efficient Fe/S-oxidizing phylotypes.This research was supported by the National Institute of Environmental Health Sciences [grant numbers P42 ES04940, R01 ES017079]; Additional support for AVV was provided by the American Society of Microbiology Robert D Watkins Graduate Research Fellowship and Alfred P. Sloan Foundation scholarship.24 month embargo; published online: 10 November 2017This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Canonical Correspondence Analysis (CCA) of the relationship between operational parameters and bacterial community structure.
<p>The ordination was based on square-root transformed data of the measured operational parameters (arrows): BOD-influent (A), Flow (B), F/M (C), HRT (D), NO<sub>3</sub><sup>–</sup>N (E), pH (F), PO<sub>4</sub><sup>3−</sup> (G), SRT (H), Temperature (I), TSS-influent (J); and the T-RFLP abundance profiles from both CAS bioreactors: HC (•), LC (▪). Numbers next to symbols indicate the relative sampling time. An unrestricted Monte-Carlo permutation test was performed (1000 permutations) to determine the statistical significance of the relationship between the environmental variables and the canonical axes.</p
Temporal variations of TSS (A) and BOD (B) removal efficiencies.
<p>Percentage values represent the difference between measured influent and effluent concentrations of TSS and BOD for both WWTP: HC (•), LC (▪).</p
Correlation analyses of the relationship between plants’ influent and effluent BOD concentrations.
<p>LC (A) and HC (B). The Pearson’s correlation coefficient (r), the linear regression coefficient of determination (R<sup>2</sup>) and the probability value (<i>P</i>) of the analysis are shown.</p
Comparison of the richness of bacterial populations (OTUs) detected in each CAS bioreactor per restriction enzyme.<sup>a</sup>
a<p>CAS: Conventional Activated Sludge; OTU: Operational Taxonomic Unit.</p>b<p>WWTP: Wastewater Treatment Plant.</p>c<p>TRFs: Terminal Restriction Fragments; Values in parentheses represent the total number of distinctive TRFs detected per restriction enzyme in both bacterial communities combined during the 12 samplings times.</p
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