Cathodoluminescence study of ZnO wafers cut from hydrothermal crystals

ZnO is a wide bandgap semiconductor with very promising expectation for UV optoelectronics. The existence of large crystals should allow homoepitaxial growth of ZnO films for advanced optoelectronic devices. However, the ZnO substrates are not yet mature. Both defect induced by growth and by polishing together with the high reactivity of the surface are problems to their industrial application. Cathodoluminescence (CL) was used to probe the quality of substrates from two different suppliers. The surface damage was studied by varying the penetration depth of the electron beam, allowing to observe significant differences between the two samples within a 0.5-mm-thick surface layer. CL spectra show a complex band (P1) at _3.3 eV composed of two overlapped bands (3.31 and 3.29 eV) related to point defects (PD) and the 1-LO phonon replica of the free exciton (FX-1LO). This band (P1) is shown to be very sensitive to the presence of defects and the surface and thermal treatments. Its intensity compared with the excitonic band intensity is demonstrated to provide criteria about the quality of the substrates

Ecological characterization and conservation status of the páramos (moors) and high Andean forests of the Monquentiva and Martos wetlands (Guatavita, Cundinamarca)

A floral and structural characterization of High Andean Forests and Paramos was conducted in a future protected regional area in the Paramo of Monquentiva (Martos swamp) in the Guatavita municipality (Cundinamarca, Colombia). The largest plant formations differentiated include the High Andean forests of Weinmannia balbisiana and Clusia multiflora that contain forests of Brunellia colombiana y Weinmannia rolotii and forests of Drimys granadensis and Weinmannia tomentosa. In the paramos were characterized the scrublands of Arcytophyllum nitidum-Diplostephium phylicoides and Aragoa abietina-Puya goudotiana, the chuscales of Chusquea tessellata and Aragoa abietina, the frailejonales of Oreobolus goeppingeri-Espeletia grandiflora, Castratella pilloselloides-Espeletia barclayana and Arcytophyllum nitidum- Espeletia argéntea, the pajonales (grasslands) of Paepalanthus columbiensis-Calamagrostis effusa, the peatland with a mosaic of frailejonales, grasslands, scrublands and wetlands. An analysis of the conservation state was carried out using some key ecological attributes based on ranks found for well-conserved ecosystems in nearby protected areas. The seven plant formations associated with the ecosystems, had good conservation statuses, which implies that the protected area is in a desirable state. It is suggested that management actions focus on continuing the decrease in stressors, natural recuperation and participatory monitoring of the process

Los páramos y bosques altoandinos del pantano de Monquentiva o pantano de Martos (Guatavita, Cundinamarca, Colombia): caracterización ecológica y estado de conservación

A floral and structural characterization of High Andean Forests and Paramos was conducted in a future protected regional area in the Paramo of Monquentiva (Martos swamp) in the Guatavita municipality (Cundinamarca, Colombia). The largest plant formations differentiated include the High Andean forests of Weinmannia balbisiana and Clusia multiflora that contain forests of Brunellia colombiana y Weinmannia rolotii and forests of Drimys granadensis and Weinmannia tomentosa. In the paramos were characterized the scrublands of Arcytophyllum nitidum-Diplostephium phylicoides and Aragoa abietina-Puya goudotiana, the chuscales of Chusquea tessellata and Aragoa abietina, the frailejonales of Oreobolus goeppingeri-Espeletia grandiflora, Castratella pilloselloides-Espeletia barclayana and Arcytophyllum nitidum- Espeletia argéntea, the pajonales (grasslands) of Paepalanthus columbiensis-Calamagrostis effusa, the peatland with a mosaic of frailejonales, grasslands, scrublands and wetlands. An analysis of the conservation state was carried out using some key ecological attributes based on ranks found for well-conserved ecosystems in nearby protected areas. The seven plant formations associated with the ecosystems, had good conservation statuses, which implies that the protected area is in a desirable state. It is suggested that management actions focus on continuing the decrease in stressors, natural recuperation and participatory monitoring of the process.Se realizó la caracterización florística y de la estructura de los bosques altoandinos y páramos de una futura área protegida regional en el páramo de Monquentiva (pantano de Martos) en el municipio de Guatavita (Cundinamarca, Colombia). Las grandes formaciones diferenciadas incluyen a los bosques altoandinos de Weinmannia balbisiana y Clusia multiflora, que incluye a los bosques de Brunellia colombiana y Weinmannia rolotii y a los bosques de Drimys granadensis y Weinmannia tomentosa. En los páramos se caracterizaron los matorrales de Arcytophyllum nitidum-Diplostephium phylicoides y Aragoa abietina-Puya goudotiana, los chuscales de Chusquea tessellata y Aragoa abietina, los frailejonales de Oreobolus goeppingeri-Espeletia grandiflora, Castratella pilloselloides-Espeletia barclayana y Arcytophyllum nitidum-Espeletia argéntea, los pajonales de Paepalanthus columbiensis-Calamagrostis effusa, la turbera con un mosaico de frailejonales, pajonales, matorrales y humedales. Se realizó un análisis de estado de conservación a partir de algunos atributos ecológicos claves basados en rangos encontrados para algunos ecosistemas bien conservados en áreas protegidas cercanas. Los siete tipos de vegetación asociados a los ecosistemas presentaron un buen estado de conservación, lo cual implica que el área protegida se encuentra en un estado deseable. Se sugiere que las acciones de manejo deberían enfocarse en continuar la disminución de los tensionantes, la recuperación natural y el monitoreo participativo del proceso

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Análisis funcional del secuestro de carbono en un bosque seco tropical interandino

Changes in functional traits related to carbon sequestration during secondary succession of Dry Tropical Forest (DTF) in Colombia are poorly understood. Here we analyze how carbon sequestration shifts along three successional stages: abandoned pastures, shrubs, and secondary forests, following a trait-based approach at both species and community level. We measured seven functional traits in 41 abundant woody species. We identified four plant functional types (PFTs) related to conservative and acquisitive strategies. Both basal area and relative abundance of acquisitive PFT decreased through successional stages. In contrast, the patterns of change for conservative PFT were less consistent. The Community-weighted mean (CWM) for specific leaf area, leaf dry matter content, wood density, and maximum height were significantly higher in secondary forests compared to early successional stages. These findings may help to broaden the understanding of carbon sequestration during DTF succession. © 2019, Universidad Nacional de Colombia. All rights reserved

Análisis funcional del secuestro de carbono en un bosque seco tropical interandino

Changes in functional traits related to carbon sequestration during secondary succession of Dry Tropical Forest (DTF) in Colombia are poorly understood. Here we analyze how carbon sequestration shifts along three successional stages: abandoned pastures, shrubs, and secondary forests, following a trait-based approach at both species and community level. We measured seven functional traits in 41 abundant woody species. We identified four plant functional types (PFTs) related to conservative and acquisitive strategies. Both basal area and relative abundance of acquisitive PFT decreased through successional stages. In contrast, the patterns of change for conservative PFT were less consistent. The Community-weighted mean (CWM) for specific leaf area, leaf dry matter content, wood density, and maximum height were significantly higher in secondary forests compared to early successional stages. These findings may help to broaden the understanding of carbon sequestration during DTF succession. © 2019, Universidad Nacional de Colombia. All rights reserved

Diversidad y caracterización florística estructural de la vegetación arbórea en la Reserva Forestal Carpatos (Guasca Cundinamarca)

The present ecological study characterized the vegetal component of the Reserva Forestal Cárpatos --Cárpatos Forest Natural Reserve- from a floral and structural point of view, by fourteen hazards sampling of a 1000m2 each one, and was to relate it the most representative environmental variables of the area of studies. The diversity reported 54 species, 41 genera and 29 families. From an analysis classification with the method Twispan of the program PC-ORD, it was found that in the reserve two new associations Ocoteo callophyllae - Weinmannietum pinnatae and Clusio multiflorae - Weinmannietum balbissianae prevail, differentiated both floristically as well as structurally.Con el presente estudio ecológico se caracterizó el componente boscoso de la Reserva Forestal Cárpatos mediante un enfoque florístico y fisionómico a partir de un muestreo simple al azar con 14 levantamientos de 1000m2 cada uno; y se relacionó dicho componente con las variables ambientales más representativas del área de estudio. En total se encontraron 54 especies arbóreas, pertenecientes a 41 géneros y 29 familias. Mediante un análisis de clasificación con el método Twispan del programa PC-ORD, se describieron en la reserva dos asociaciones nuevas, Ocoteo callophyllae -- Weinmannietum pinnatae y Clusio multiflorae - Weinmannietum balbissianae, diferenciadas tanto florística como estructuralmente