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Imagen de apoyo de  Relaciones entre las políticas del Estado colombiano y la situación jurídica de las comunidades autóctonas en el desarrollo de proyectos energéticos: el caso de los Embera-Katíos y la hidroeléctrica de Urrá

Relaciones entre las políticas del Estado colombiano y la situación jurídica de las comunidades autóctonas en el desarrollo de proyectos energéticos: el caso de los Embera-Katíos y la hidroeléctrica de Urrá

Por: Carlos Martín Carbonell Higuera

El artículo presenta un análisis sobre el papel del Estado en las relaciones entre las comunidades indígenas y los proyectos hidroeléctricos en Colombia, así como las consideraciones jurídicas que se han puesto en juego en estas situaciones.El estudio toma como caso de estudio la construcción de la represa de Urrá en la región del Alto Sinú, la cual tuvo un impacto significativo sobre las condiciones de supervivencia cultural de una comunidad del pueblo Embera-Katío habitante en los territorios de influencia del proyecto.El trabajo hace un seguimiento a las decisiones judiciales de carácter constitucional respecto a la protección de los derechos de los pueblos indígenas, en el contexto de un Estado que se reconoce multicultural.
  • Acceso digital
  • Artículos
  • Publicador Prolegómenos; Vol. XIV, No. 27
  • Año de Publicación 2011
  • Idioma Francés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Nitrogen Transformation and Removal in Maturation Ponds: Tracer Experiments with 15N Stable Isotopes in The United Kingdom in Summer

Nitrogen Transformation and Removal in Maturation Ponds: Tracer Experiments with 15N Stable Isotopes in The United Kingdom in Summer

Por: Miller Alonso; Mara Camargo Valero

The mechanisms and pathways by which nitrogen in its various forms is removed from waste stabilization ponds (WSP) have been a subject of much debate. In order to improve current understanding of the dynamics of inorganic and organic nitrogen removal in WSP systems, a study using stable nitrogen isotopes (15N) was undertaken on an experimental pilot-scale WSP system at Esholt Wastewater Treatment Works (Bradford, UK) in summer 2005 and 2006.A primary maturation pond was spiked with 15N-labelled ammonia (15NH4Cl) and 15N-labelled algae (Chlorella vulgaris) to track nitrogen transformations and removal associated with ammonia volatilization, nitrification, and algal uptake and its subsequent sedimentation and retention/hydrolysis in the sludge layer. Stable isotope analysis of 15N, in conjunction with performance indicators, revealed that total nitrogen is poorly removed (? 8%) but ammonium nitrogen removal is very good in summer (effluent concentration <2 mg NH4 + -N/L).The nitrogen cycle in maturation ponds is dominated by biological uptake as ammonium nitrogen is rapidly transformed into algal biomass as suspended organic nitrogen which then either leaves in the pond effluent or is sedimented as dead cells. Ammonia removal by volatilization makes little or no contribution to nitrogen removal and biological nitrate uptake prevents classical nitrification. Thus algal uptake of ammonium and subsequent sedimentation and retention in the sludge layer, after parti al ammonification of the algal organic nitrogen, appears to be the dominant mechanism for permanent nitrogen removal in maturation ponds during warm summer months in England.
  • Acceso digital
  • Artículos
  • Año de Publicación 2007
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
    • Ingeniería
Imagen de apoyo de  Endophilia or exophobia: beyond discrimination = Endofilia o exofobia: más allá de discriminación

Endophilia or exophobia: beyond discrimination = Endofilia o exofobia: más allá de discriminación

Por: Nicolás; Feld Salamanca Acosta

The immense literature on discrimination treats outcomes as relative: One group suffers compared to another. But does a difference arise because agents discriminate against others—are exophobic—or because they favor their own kind—are endophilic? This difference matters, as the relative importance of the types of discrimination and their inter-relation affect market outcomes.Using a field experiment in which graders at one university were randomly assigned students’ exams that did or did not contain the students’ names, on average we find favoritism but no discrimination by nationality, and neither favoritism nor discrimination by gender, findings that are robust to a wide variety of potential concerns. We observe heterogeneity in both discrimination and favoritism by nationality and by gender in the distributions of graders’ preferences. We show that a changing correlation between endophilia and exophobia can generate perverse changes in observed market discrimination.
  • Acceso digital
  • Artículos
  • Año de Publicación 2013
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Ecological factors influencing group sizes of river dolphins : Inia geoffrensis and Sotalia fluviatilis

Ecological factors influencing group sizes of river dolphins : Inia geoffrensis and Sotalia fluviatilis

Por: Catalina; Trujillo Gómez Salazar

Living in groups is usually driven by predation and competition for resources. River dolphins do not have natural predators but inhabit dynamic systems with predictable seasonal shifts. These ecological features may provide some insight into the forces driving group formation and help us to answer questions such as why river dolphins have some of the smallest group sizes of cetaceans, and why group sizes vary with time and place.We analyzed observations of group size for Inia and Sotalia over a 9 yr period.In the Amazon, largest group sizes occurred in main rivers and lakes, particularly during the low water season when resources are concentrated; smaller group sizes occurred in constricted waters (channels, tributaries, and confluences) that receive an influx of blackwaters that are poor in nutrients and sediments.In the Orinoco, the largest group sizes occurred during the transitional water season when the aquatic productivity increases. The largest group size of Inia occurred in the Orinoco location that contains the influx of two highly productive whitewater rivers. Flood pulses govern productivity and major biological factors of these river basins. Any threats to flood pulses will likely have an effect on the functionality of these ecosystems and the species living in them.
  • Acceso digital
  • Artículos
  • Publicador Marine Mammal Science; Vol. 28, No. 2
  • Año de Publicación 2011
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Determining public values of urban forests using a sidewalk interception survey in Fredericton, Halifax, and Winnipeg, Canada

Determining public values of urban forests using a sidewalk interception survey in Fredericton, Halifax, and Winnipeg, Canada

Por: Camilo; Duinker Ordoñez Barona

With the majority of Canada’s population concentrated in cities, it is important to determine what people consider important in urban nature. The concept of values can help illustrate what people consider important in urban nature beyond utilitarian considerations. This is the case for urban forests.However, many studies about public opinion on urban forests do not capture expressions of importance, focus on all the trees of the city, or provide respondents with a direct experience of urban forests. In Canada, most assumptions about Canadian urban forest values are based on results from the United States.In this study researchers present and analyze urban forest values data gathered with a sidewalk interception survey in the cities of Fredericton, New Brunswick; Halifax, Nova Scotia; and Winnipeg, Manitoba, Canada, to address some of these limitations. Respondents were asked to rate the level of importance of urban forests and mention the reasons.Results show that respondents rate the urban forest at a high level of importance and the reasons for this are aesthetics, air quality, shade, and naturalness, among other themes. There was a tendency for older people, women, and non-students to rate urban forests at a higher level of importance.Weather, related to time of year of survey delivery, has a discernible influence on the way value themes are distributed in the data. The study authors infer that this method helps capture data on respondents’ psychological states instead of their intellectual awareness as to what they consider important about urban forests.
  • Acceso digital
  • Artículos
  • Publicador Arboriculture & Urban Forestry; Vol. 42, No. 1
  • Año de Publicación 2016
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  New records and distribution extensions of some bird species in the Colombian Andean-Orinoco, department of Meta

New records and distribution extensions of some bird species in the Colombian Andean-Orinoco, department of Meta

Por: Johanna Isabel; Bonilla Rojas Murillo Pacheco

Abstract:Here we present new records for four bird species to the Andean foothills of the department of Meta in Colombia, and we confirm the occurrence and document range extensions for these in the basin of the Orinoco river.These species are the Pied-billed Grebe, Podilymbus podiceps (Linnaeus 1758), the Yellowchinned Spinetail, Certhiaxis cinnamomeus (Gmelin 1788), the Yellow-browed Tyrant, Satrapa icterophrys (Viellot 1818), and the Glossy Ibis, Plegadis falcinellus (Linnaeus 1766).We also report new sightings of the Prothonotary Warbler, Protonotaria citrea (Boddaert 1783), Least Grebe, Tachybaptus dominicus (Linnaeus 1766), Oilbird, Steatornis caripensis (Humboldt 1817) and Epaulet Oriole, Icterus cayanensis (Linnaeus 1766) in the Colombian Andean-Orinoco (Meta department).Resumen:Aquí presentamos nuevos registros para cuatro especies de aves para las estribaciones Andinas del Departamento del Meta en Colombia, y confirmamos la ocurrencia y documentamos la extensión de rango para éstas especies en la cuenca del río Orinoco.Estas especies son el Zambullidor común Podilymbus podiceps (Linnaeus 1758), el chamicero barbiamarillo, Certhiaxis cinnamomeus (Gmelin 1788), el mosquero cejiamarillo, Satrapa icterophrys (Viellot 1818), y el ibis pico de hoz, Plegadis falcinellus (Linnaeus 1766).También reportamos nuevos registros de la Reinita cabecidorada, Protonotaria citrea (Boddaert 1783), el zambullidor chico, Tachybaptus dominicus (Linnaeus 1766), el guacharo, Steatornis caripensis (Humboldt 1817) y el turpial boyerito, Icterus cayanensis (Linnaeus 1766) en el Orinoco Andino de Colombia (departamento del Meta).
  • Acceso digital
  • Artículos
  • Publicador Checklist Journal; Vol. 12, No. 2
  • Año de Publicación 2016
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Strategic portfolio management framework Queensland Rail National

Strategic portfolio management framework Queensland Rail National

Por: Mario Jheinner; Leake Vargas Cubides

The commercial businesses of Queensland Rail (QR) were separated from the Government’s public transport business on 1 July 2010. QR National Limited will be sold via an Initial Public Offering (IPO) – sometimes referred to as a public float planned for the final quarter of 2010, subject to market conditions. On becoming a publicly listed company it is expected that there is great scope for increase in market share. In order to realise the opportunities available to a public company, the following undertakings are necessary:- Business and logistics improvements.- Compliance requirements.- Capital Investment.This report looks at the process to develop a program of work that will deliver on these undertakings. It describes how nominated projects were classified, scoped, prioritised and selected using a filtering process and how sub programs were packaged for delivery. Finally the report outlines a framework for execution. This framework includes an approach to governance, risk management, control of time, cost, scope and benefits realisation. Due to the limited knowledge of the inner workings of QR National, assumptions have been made based on information available in the public domain.
  • Acceso digital
  • Artículos
  • Año de Publicación 2010
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  An analysis of urban forest management plans in Canada: Implications for urban forest management

An analysis of urban forest management plans in Canada: Implications for urban forest management

Por: Camilo; Duinker Ordoñez Barona

Urban forests are an integral part of urban ecosystems and quality of city life. The urban forest in Canada is highly valued, underscoring the importance of devising schemes for sustainable urban forest management. During the last decade, many urban forest management plans (UFMPs) have been prepared.This study analyses 14 Canadian UFMPs published in this period. We found that most of the UFMPs are dominated by an approach that relies on single-tree maintenance, canopy-cover enhancement, tree-diversity enhancement, and planting-oriented educational programmes.These activities dominate the operational features of the plans, while other ecological, social, and economic considerations lack specificity and operational clarity. A suite of best management practices based on UFMP documentation is included here.
  • Acceso digital
  • Artículos
  • Publicador Landscape and Urban Planning; Vol. 116
  • Año de Publicación 2013
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Assessing the vulnerbarility of urban forests to climate change

Assessing the vulnerbarility of urban forests to climate change

Por: Camilo; Duinker Ordoñez Barona

Climate adaptation is being embraced by many municipalities worldwide. An element of this is the planting and protection of urban trees. However, the fact that climate change will also have an impact on urban trees has been largely overlooked. We argue that climate vulnerability assessments are necessary for addressing climate adaptation in urban forests and contribute to successful climate adaptation in cities.We review and integrate the literature on climate vulnerability and urban forests to explore how the general notion of urban forest vulnerability to climate change can be developed into an operational framework for undertaking a vulnerability assessment. The framework characterizes climate exposure, impact, sensitivity, and adaptive capacity, as well as nonclimatic drivers and factors, in urban forests.The most important themes in this discussion include urban tree species selection and diversity, naturalization, resource access, social awareness and engagement, budget and economic valuation, liability issues, and governance structures.Climate change vulnerability assessments help us understand how and why urban forests are vulnerable to climate change, identify future areas for research, and determine what adaptation measures could be included in urban forest management. These assessments help bring climate change to the forefront of the decision-making process and contribute to successful urban adaptation to climate change.
  • Acceso digital
  • Artículos
  • Publicador Environmental Reviews; Vol. 22, No. 3
  • Año de Publicación 2014
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Clinical characteristics of patients with concomitant oral lichen planus and thyroid disease

Clinical characteristics of patients with concomitant oral lichen planus and thyroid disease

Por: Jairo; Wilhelmsen Robledo Sierra

Abstract:OBJECTIVE:To study the prevalence and profile of thyroid disease in a cohort of referred patients with oral lichen planus (OLP) in comparison with a random population sample and to examine the clinical characteristics of OLP patients with and without thyroid disease.STUDY DESIGN:Data from 1611 patients with OLP and 1615 patients from the general population were collected by using a standardized registration method. Patients with OLP using levothyroxine (OLP/levothyroxine+) were re-examined to collect information about existing OLP lesions and to confirm the thyroid disease diagnosis. The clinical characteristics of OLP lesions in this group were compared with those in an age- and gender-matched population of patients with OLP without a history of thyroid disease or levothyroxine medication (OLP/levothyroxine-).RESULTS:Nearly 11% (n = 170) of the patients with OLP were taking levothyroxine compared with 2.5% (n = 40) of the controls (multivariate odds ratio 2.99, 95% confidence interval 2.03-4.44; P < .0001). No difference was found in the thyroid disease profile between the groups. At the time of re-examination, patients with OLP/levothyroxine- displayed more erythematous OLP lesions and complained of more severe symptoms compared with the OLP/levothyroxine+ group (P < .001).CONCLUSION:The prevalence of thyroid disease in patients with OLP was significantly higher than in the general population. The OLP lesions of patients with concomitant thyroid disease have a different presentation over time, which indicates a specific subgroup of OLP."Resumen: OBJETIVO: Estudiar la prevalencia y el perfil de la enfermedad de la tiroides en una cohorte de pacientes remitidos con liquen plano oral (LPO) en comparación con una muestra aleatoria de una, y examinar las características clínicas de pacientes con LPO con y sin enfermedad de la tiroides. DISEÑO DEL ESTUDIO: Datos de 1.611 pacientes con LPO y 1.615 pacientes de la población general fueron recolectados usando un método estandarizado de registro. Los pacientes con LPO que estaban usando levotiroxina (LPO/levotiroxina+) fueron reexaminados para recolectar información sobre la existencia de lesiones de LPO y confirmar el diagnóstico de la enfermedad de la tiroides. Las características clínicas del LPO en este grupo fueron comparadas con un grupo, emparejado para edad y sexo, de pacientes con LPO sin historia de enfermedad de la tiroides o uso de levotiroxina (LPO/levotiroxina-). RESULTADOS: Aproximadamente el 11% (n = 170) de los pacientes con LPO estaban medicados con levotiroxina comparado con el 2.5% (n = 40) de los controles (OR multivariado 2.99, 95% CI 2.03-4.44; P < .0001). No se encontraron diferencias entre el perfil de la enfermedad de la tiroides entre los grupos. En el momento de la reexaminación, los pacientes con LPO/levotiroxina- mostraron más lesiones eritematosas de LPO y se quejaron de síntomas más severos en comparación con el grupo LPO/levotiroxina+ (P < .001). CONCLUSIÓN: La prevalencia de la enfermedad de la tiroides en pacientes con LPO es significativamente mayor que en la población general. Las lesiones de LPO en pacientes con enfermedad de la tiroides concomitante tiene una presentación diferente a través del tiempo, lo cual indica un subgrupo específico de LPO."
  • Acceso digital
  • Artículos
  • Publicador Oral Surgery Oral Medicine Oral Pathology Oral Radiology; Vol. 120, No. 5
  • Año de Publicación 2015
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
    • Medicina
Imagen de apoyo de  Prevention and Control of Air Pollution in China: A Research Agenda for Science and Technology Studies

Prevention and Control of Air Pollution in China: A Research Agenda for Science and Technology Studies

Por: Rodolfo Andrés Hernández Pérez

hina’s air pollution has reached a critical state, and is characterized by heavy coal smoke and a wide presence of ozone and particulate matter (PM2.5). From 2011, through the 12th five year plan, the prevention and control of air pollution entered a new ‘transition stage’ guided by the principles of sustainability and energy conservation, and also intensified by pressure from the society.This article is divided into two parts: first, it introduces the most important changes, problems and advances during this transition, including a brief explanation of the policy mechanisms. Second, it illustrates how research in the area of Science and Technology Studies (STS) can bring about new ways to understand the problems of the knowledge-policy and public engagement of air pollution in China.
  • Acceso digital
  • Artículos
  • Publicador S.A.P.I.E.N.S.; Vol. 8, No. 1
  • Año de Publicación 2015
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
    • Ingeniería
Imagen de apoyo de  Cardiac-specific overexpression of thioredoxin 1 attenuates mitochondrial and myocardial dysfunction in septic mice

Cardiac-specific overexpression of thioredoxin 1 attenuates mitochondrial and myocardial dysfunction in septic mice

Por: Juana Patricia; D’Annunzio Sánchez Villamil

Abstract:Sepsis-induced myocardial dysfunction is associated with increased oxidative stress and mitochondrial dysfunction. Current evidence suggests a protective role of thioredoxin-1 (Trx1) in the pathogenesis of cardiovascular diseases. However, it is unknown yet a putative role of Trx1 in sepsis-induced myocardial dysfunction, in which oxidative stress is an underlying cause.Transgenic male mice with Trx1 cardiac-specific overexpression (Trx1-Tg) and its wild-type control (wt) were subjected to cecal ligation and puncture or sham surgery. After 6, 18, and 24 h, cardiac contractility, antioxidant enzymes, protein oxidation, and mitochondrial function were evaluated. Trx1 overexpression improved the average life expectancy (Trx1-Tg: 36, wt: 28 h; p=0.0204).Sepsis induced a decrease in left ventricular developed pressure in both groups, while the contractile reserve, estimated as the response to ?-adrenergic stimulus, was higher in Trx1-Tg in relation to wt, after 6 h of the procedure. Trx1 overexpression attenuated complex I inhibition, protein carbonylation, and loss of membrane potential, and preserved MnSOD activity at 24 h.Ultrastructural alterations in mitochondrial cristae were accompanied by reduced Optic atrophy 1 (OPA1) fusion protein, and activation of dynamin-related protein 1 (Drp1) (fission protein) in wt mice at 24 h, suggesting mitochondrial fusion/fission imbalance. PGC-1? gene expression showed a 2.5-fold increase in Trx1-Tg at 24 h, suggesting mitocondrial biogenesis induction. Autophagy, demonstrated by electron microscopy and increased LC3-II/LC3-I ratio, was observed earlier in Trx1-Tg. In conclusion, Trx1 overexpression extends antioxidant protection, attenuates mitochondrial damage, and activates mitochondrial turnover (biogenesis and mitophagy), preserves contractile reserve and prolongs survival during sepsis.Resumen: La disfunción miocárdica inducida por sepsis está asociada con estrés oxidativo y disfuncion mitocontrial. La evidencia actual sugiere un rol protector de thiorredoxina 1 en la patogénesis de la enfermedad cardiovascular. Sin embargo, es desconocido su papel en la disfunción miocárdica inducida por sepsis, en el cual el estrés oxidativo es una causa subyacente. Ratones transgénicos machos con sobreexpresión específica en músculo cardiaco (Trx1-Tg) y su control (wt) fueron sujetos a ligadura punción cecal o técnica de laparotomía sin ligadura y punción (sham). Después de 6, 18,y 24h, contractilidad cardiaca, enzimas antioxidantes, oxidación de proteínas, y función mitocondrial fueron evaluados. Sobre-expresión de Trx1 mejoró la esperanza de vida media (Trx1-Tg: 36, wt: 28 h; p = 0.0204). Sepsis indujo una reducción en la presión desarrollada del ventrículo izquierdo en ambos grupos, mientras la reserva contráctil, estimada como la respuesta al estímulo β-adrenérgico, fue superior en Trx1-Tg en relación a wt, posterior a 6 h del procedimiento.La sobre-expresión de Trx1 atenuó la inhibición del complejo I, carbonilación de proteínas, y pérdida de potencial de membrana, y preservó la actividad de la superóxido dismutasa-Mn a las 24 h. Alteraciones ultra estructurales en las crestas mitocondriales fueron acompañadas por una reducción en OPA1 y activación de Drp1 en ratones wt a las 24 h, sugiriendo un imbalance fusión/fisión mitocondrial. La expresión de PGC-1-α incrementó 2.5 veces en Trx1-Tg a las 24 h, sugiriendo inducción de biogénesis mitocondrial. Autofagia, demostrada por microscopia electrónica e incremento en la razón LC3-II/LC3-I, fue observado más tempranamente en Trx1-Tg. En conclusión, la sobre-expresión de Trx1 extiende protección antioxidante, atenúa el daño mitocondrial y activa el recambio mitocondrial (mitofagia y biogénesis), preserva la reserva contráctil y prolonga la sobrevida durante la sepsis.
  • Acceso digital
  • Artículos
  • Publicador The International Journal of Biochemistry & Cell Biology; Vol. 81, Parte B
  • Año de Publicación 2016
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
    • Medicina
Imagen de apoyo de  Asphyxial suicide by inhalation of chloroform inside a plastic bag

Asphyxial suicide by inhalation of chloroform inside a plastic bag

Por: Andrés Rodríguez Zorro

Abstract:Asphyxia suicide by placing a plastic bag over the head in addition with inhalation of gases or use of sedative substances is an unusual method of committing suicide, but frequently referenced by right to die groups in the Internet.This article reports 2 suicides in which chloroform was used to induce unconsciousness and subsequent asphyxia by placing the head in a plastic bag. Case histories of two young Colombian males, ages 23 and 28, are described with special emphasis on characteristics of death related to suffocation using plastic bags and chloroform.The final remarkable point in both cases is that the victims previously searched the WEB for instructions of suicide methods. The importance of the phenomenon of misuse of Internet by young people who commit suicide is stressed.Resumen:El suicidio por asfixia mediante la colocación de una bolsa de plástico sobre la cabeza, además de la inhalación de gases o el uso de sustancias sedantes es un método inusual de cometer suicidio, pero es frecuentemente referenciado por los grupos que apoyan el derecho al suicidio en Internet.Este artículo reporta 2 casos de suicidios en los que se usó cloroformo para inducir la inconsciencia y la asfixia subsecuente colocando la cabeza en una bolsa de plástico. Se describen las historias de 2 jóvenes colombianos, de edades comprendidas entre 23 y 28 años, con especial énfasis en las características de su muerte relacionadas con la asfixia mediante bolsas de plástico y cloroformo.El último punto notable en ambos casos es que las víctimas previamente buscaron en la WEB instrucciones de métodos suicidas. Se resalta la importancia del fenómeno del mal uso de Internet por parte de los jóvenes con alto riesgo suicida.
  • Acceso digital
  • Artículos
  • Publicador Journal of Forensic and Legal Medicine; Vol. 21
  • Año de Publicación 2014
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  The impact of marketing systems on soil sustainability of agriculture in developing countries: a method and an application

The impact of marketing systems on soil sustainability of agriculture in developing countries: a method and an application

Por: Jairo; Meulenberg Castaño Galves

This article is concerned with soil-sustainability problems of agriculture in developing countries, in particular with soil erosion. The aim of our study is to develop a comprehensive model that explains the adoption of sustainable agricultural practices with respect to soil conservation. Our approach includes the following special features:(A) The model is comprehensive in that it includes a large number of institutional, personal–social, economic, and physical explanatory variables.(B) Particular attention is paid to the influence of marketing systems on the adoption of sustainable agricultural practices, which to our knowledge has been neglected in past research.(C) The concept of adopting sustainable agricultural practices (ASAP) is differentiated into a limited number of basic components of soil conservation.(D) The model is estimated by Principal Component Regression, which enhances efficient estimation of the impact of many explanatory variables on ASAP. Our model is applied to Cabuyal hillside farming in Colombia. The application demonstrates the usefulness of the proposed model.ASAP is differentiated into three basic components: soil-disturbance control, soil-protection practices, and run-off control. It appears that soil-disturbance control is particularly influenced by farmers’ characteristics, such as education and managerial variables.The second component, soil-protection practices, appears to be strongly influenced not only by farmers’ managerial variables but also by their relationship with their environment, in particular marketing institutions.The third soil-conservation component, run-off control, is influenced by the physical characteristics of the plot and by the available farm labor. Our empirical results demonstrate the usefulness of the proposed model in designing agricultural policies, because it can determine which variables are more likely to influence the adoption of a specific type of soil conservation.
  • Acceso digital
  • Artículos
  • Publicador Agricultural Economics; Vol. 33, No. 1
  • Año de Publicación 2005
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Functionalization of CoCr surfaces with cell adhesive peptides to promote HUVECs adhesion and proliferation

Functionalization of CoCr surfaces with cell adhesive peptides to promote HUVECs adhesion and proliferation

Por: María Isabel; Mas-Moruno Castellanos Arboleda

Biomimetic surface modification with peptides that have specific cell-binding moieties is a promising approach to improve endothelialization of metal-based stents. In this study, we functionalized CoCr surfaces with RGDS, REDV, YIGSR peptides and their combinations to promote endothelial cells (ECs) adhesion and proliferation.An extensive characterization of the functionalized surfaces was performed by XPS analysis, surface charge and quartz crystal microbalance with dissipation monitoring (QCM-D), which demonstrated the successful immobilization of the peptides to the surface.Cell studies demonstrated that the covalent functionalization of CoCr surfaces with an equimolar combination of RGDS and YIGSR represents the most powerful strategy to enhance the early stages of ECs adhesion and proliferation, indicating a positive synergistic effect between the two peptide motifs.Although these peptide sequences slightly increased smooth muscle cells (SMCs) adhesion, these values were ten times lower than those observed for ECs. The combination of RGDS with the REDV sequence did not show synergistic effects in promoting the adhesion or proliferation of ECs. The strategy presented in this study holds great potential to overcome clinical limitations of current metal stents by enhancing their capacity to support surface endothelialization.
  • Acceso digital
  • Artículos
  • Publicador Applied Surface Science; Vol. 393
  • Año de Publicación 2017
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Decision making approach to a maintenance audit development

Decision making approach to a maintenance audit development

Por: Pedro E. Cruz

Purpose – The purpose of this paper is to demonstrate that through the maintenance systems theory an audit methodology can be developed so it can be linked to a decision making process methodology to fully support the actions and initiatives proposed for improvement.Design/methodology/approach - The methodology is delimited by the concept of maintenance systems, from where a maintenance audit is developed to allow an integration of the Decision Making Grid (DMG) concept in order to add a basis of decision making and help in the prioritization process.Findings – This paper discuss an approach to the maintenance audits integrating well-established concepts of maintenance engineering and a decision making technique, which leads to an audit result-decision matrix that can show to the organization the wrong paths and shortcomings that are required to be solved in order to progress and close the gap to reach their desired performance.Originality/Value – Although there is a wide range of techniques developed to assess and audit, most of them imply a large and elaborated method not only for the questions (which are inevitable when assessing) but also to understand the findings and elaborate recommendations. The paper explores the integration of a defined maintenance system, its boundaries and its interactions, while mapping those concepts within a decision matrix.
  • Acceso digital
  • Artículos
  • Año de Publicación 2012
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Latent gender inequalities in the well-being of physicians according to payment method for practicing medicine: a cross-sectional study

Latent gender inequalities in the well-being of physicians according to payment method for practicing medicine: a cross-sectional study

Por: Juan Nicolás; Bermedo Carrasco Peña Sánchez

Background: Female physicians face extra challenges in their career development and tend to choose salary or other forms of alternative payment plans (APP). Fee-for-service (FFS) and APP may affect the well-being of female and male physicians differently. Three measures of well-being are: levels of career satisfaction, professional equity, and daily distress. The objectives are to identify differences in the levels of career satisfaction, fulfillment-recognition equity, and daily distress of physicians by gender and payment method, and to assess interactions between these two factors.Methods: A cross-sectional study was conducted in 2011 with physicians practicing in the Saskatoon Health Region, Saskatchewan, Canada. Resident physicians were excluded from the study. Eligible physicians completed a survey, assessing levels of daily distress, fulfillment-recognition equity, and career satisfaction as dependent variables. A multivariate analysis of variance (MANOVA), using the Wilks’ Lambda criterion, was conducted to study differences among the dependent variables by remuneration method and gender. Multiple comparisons were performed as post-hoc tests.Results: Nearly half (382) of the 794 eligible physicians completed the questionnaire; 37.2% were female. Half were remunerated by FFS, a quarter by APP, and the remainder by blended forms. Career satisfaction and fulfillment-recognition equity were positively correlated to each other and daily distress was negatively correlated with both. According to the MANOVA results, the dependent variables were affected by gender but not by payment method, and there was no evidence of an interaction effect between payment method and gender. Women reported lower levels of career satisfaction (p=0.01) and fulfillment-recognition equity (p=0.01), and higher levels of daily distress (p=0.03).
  • Acceso digital
  • Artículos
  • Publicador Journal of Hospital Administration; Vol. 2, No. 4
  • Año de Publicación 2013
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Autophagy Proteins ATG5 and ATG7 Are Essential for the Maintenance of Human CD34(+) Hematopoietic Stem-Progenitor Cells

Autophagy Proteins ATG5 and ATG7 Are Essential for the Maintenance of Human CD34(+) Hematopoietic Stem-Progenitor Cells

Por: María Catalina; Folkerts Gómez Puerto

Abstract:Autophagy is a highly regulated catabolic process that involves sequestration and lysosomal degradation of cytosolic components such as damaged organelles and misfolded proteins. While autophagy can be considered to be a general cellular housekeeping process, it has become clear that it may also play cell type-dependent functional roles.In this study, we analyzed the functional importance of autophagy in human hematopoietic stem/progenitor cells (HSPCs), and how this is regulated during differentiation. Western blot-based analysis of LC3-II and p62 levels, as well as flow cytometry-based autophagic vesicle quantification, demonstrated that umbilical cord blood-derived CD34(+) /CD38(-) immature hematopoietic progenitors show a higher autophagic flux than CD34(+) /CD38(+) progenitors and more differentiated myeloid and erythroid cells.This high autophagic flux was critical for maintaining stem and progenitor function since knockdown of autophagy genes ATG5 or ATG7 resulted in reduced HSPC frequencies in vitro as well as in vivo. The reduction in HSPCs was not due to impaired differentiation, but at least in part due to reduced cell cycle progression and increased apoptosis.This is accompanied by increased expression of p53, proapoptotic genes BAX and PUMA, and the cell cycle inhibitor p21, as well as increased levels of cleaved caspase-3 and reactive oxygen species. Taken together, our data demonstrate that autophagy is an important regulatory mechanism for human HSCs and their progeny, reducing cellular stress and promoting survival.Resumen: La autofagia es un proceso lisosomal catabólico altamente regulado que implica el secuestro y degradación de componentes citosólicos: tales como proteínas mal plegadas y orgánelos deteriorados. Mientras que la autofagia puede ser considerada como un proceso general de limpieza celular, también juega un papel funcional dependiendo del tipo de célula.En el presente estudio, hemos analizado la importancia de la autofagia en las células madre hematopoyéticas y sus progenitores y cómo dicho proceso está regulado durante la diferenciación. El análisis de los niveles de LC3-II y p62, así como la cuantificación de la autofagia mediante citometría de flujo demostraron que los progenitores hematopoyéticos inmaduros CD34 (+) / CD38 (-) tienen un flujo de autofagia mayor que las células eritroides y mieloides. Este alto flujo de autofagia es crucial para las células madre y los progenitores hematopoyéticos inmaduros CD34 (+) / CD38 (-) ya que la disminución en los niveles de ATG7 y ATG5 resulta en una reducción de dichas células tanto in vitro como in vivo.Lo anterior es consecuencia de la inhibición parcial del ciclo celular y de un aumento en apoptosis. Adicionalmente, observamos un incremento en la expresión de p53, los genes pro-apoptosis BAX y PUMA, el inhibidor de ciclo celular p21, los niveles de caspasa-3 clivada y las especies reactivas del oxígeno.En conclusión, nuestros datos demuestran que la autofagia es un mecanismo de regulación importante para las células madre hematopoyéticas y sus progenitores reduciendo los niveles de estrés y promoviendo su supervivencia.
  • Acceso digital
  • Artículos
  • Publicador Stem cells; Vol. 34, No. 6
  • Año de Publicación 2016
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
    • Medicina
Imagen de apoyo de  Queensland Rail National program management

Queensland Rail National program management

Por: Mario Jheinner Vargas Cubides

The creation of the PMO as a centralized unit formalizes project practices increasing the level of maturity. The expected level in the maturity model is to develop a continuously improvement in project management among the portfolio in all the stages of the project life cycle.This expectation could be achievable due to from the creation of the PMO the objective is to standardize, measure, control and communicate the PM practices. The other factor that enhances this level of maturity expected is that the head and the board of the organization have pointed out the benefits of use project management.
  • Acceso digital
  • Artículos
  • Año de Publicación 2010
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros
Imagen de apoyo de  Trees in Canadian Cities: Indispensable Life Form for Urban Sustainability

Trees in Canadian Cities: Indispensable Life Form for Urban Sustainability

Por: Camilo; Duinker Ordóñez Barona

We argue that a healthy urban forest contributes immensely to the sustainability of cities. The argument is based on a comprehensive array of values elicited from Canadians in several cities. To begin, we define the urban forest as inclusive of all the trees in the city and thus representing the predominant contributor to a city’s green infrastructure.Then we enumerate and explain the broad diversity of ways in which urban people value trees in the city. We, thus, show the myriad pathways by which trees contribute positively to any city’s social, economic, and ecological sustainability.Following a short summary of the ways in which trees may detract from people’s quality of life, we present promising management directions for urban-forest improvement, as we understand the situation in Canada. We conclude that all cities can enhance their sustainability by improving the urban forest.
  • Acceso digital
  • Artículos
  • Publicador Sustainability; Vol. 7, No. 6
  • Año de Publicación 2015
  • Idioma Inglés
  • Fuente Biblioteca Virtual Banco de la República
  • Temas
    • Otros