Una mirada a la "ciudad de los 15 minutos" desde asentamientos precarios en Barranquilla y Soledad

La ciudad de los 15 minutos es una tendencia mundial que busca establecer nuevas dinámicas de planificación urbana basadas en la policentralidad, el microurbanismo y la cronotopia; en donde los habitantes puedan realizar sus funciones sociales, urbanas y territoriales esenciales a pie o en bicicleta en quince minutos desde sus hogares. Sin embargo, este concepto no se ha evaluado en contextos informales o precarios como los que se encuentran en algunas ciudades de América Latina. Según UN-Hábitat, los asentamientos informales o precarios se caracterizan por su "falta de servicios básicos, vivienda por debajo de los estándares o ilegal y estructuras inadecuadas de construcción, hacinamiento y alta densidad, condiciones de vida insalubres y localización en zonas de riesgo e inseguridad en la tenencia". Con el fin de evaluar este concepto en asentamientos de este tipo, en el presente estudio se recopilaron 300 encuestas domiciliarias en cuatro asentamientos precarios de las ciudades de Barranquilla y Soledad. Se encontró que la mayoría de las actividades obligadas diferentes al trabajo se realizan principalmente a pie dentro de la proximidad. Sin embargo, los residentes de las zonas de estudio experimentan desequilibrios de accesibilidad a las diferentes funciones sociales urbanas necesarias para alcanzar calidad de vida digna según lo plantea el concepto de Ciudad de 15 minutos. También se identificó que el comercio informal del barrio se convierte para los residentes en un soporte frente a la dificultad que tienen de moverse más lejos y conseguir empleo. Las políticas de planificación urbana juegan un papel importante en el mejoramiento de la calidad de vida de estos habitantes promoviendo la máxima proximidad a los servicios e instalaciones urbanas más habituales.MaestríaMagister en Ingeniería Civi

HEMP AND RICE STRAW VALORIZATION FOR THE DEVELOPMENT OF SUSTAINABLE ANTIOXIDANT-CELLULOSIC BASED CRYOGELS AND AEROGELS

<p>One of the strategies to ensure food safety is to extend the shelf life of food, therefore minimizing food losses and wastage. The main challenge in food production is to maintain food safety and improve nutritional and sensory quality in an affordable way. Shelf life depends on many factors, including the quality of raw materials, product formulation, type of preparation, packaging and storage conditions [1]. Active food packaging has been proposed as a potential solution to achieve this goal. Among other desired functionalities, many active packaging concepts involve the release of antioxidants substances onto the food surface, as a way of improving the stability of oxidation-sensitive food products [2]. The negative effects of oxidation on the nutritional and organoleptic properties of foods include: i) reduction in nutritional value due to destruction of essential fatty acids, proteins and lipid-soluble vitamins (A, D, E and K); ii) reduction in caloric value; iii) formation of rancidity (off-flavors); and iv) color changes due to darkening of fats and oils or degradation of pigments [3].</p><p>Mainly due to environmental concerns, novel active packaging concepts are being developed using biodegradable food packaging materials combined with natural preservatives. Therefore, the use of biopolymers, such as cellulose, has been proposed as a packaging constituent. Cellulose and its derivatives are attracting considerable attention due to their biocompatibility and environmental sustainability. Cellulose is a low-cost material with suitable mechanical properties and an excess demand in the global market. There is a large amount of agricultural waste and many processes need to be initiated to make use of this waste. For example, some of the methods used in the fabrication of cellulose-based food packaging include solution casting, layer-by-layer assembly, extrusions, coatings, polymeric hydrogels, spraying, nano-emulsions, liposomes and adsorption [4]. </p><p>In this respect, hemp (Cannabis sativa) is an easy-to-grow plant that, by its very nature, does not require fertilisers or herbicides. It also contains 40-77% cellulose, depending on the growing conditions [5]. Consequently, hemp can be used as a source of cellulose and other value-added compounds useful in the food packaging industry. One application in the meat industry is the production of absorbent pads that aim to reduce the exuded fluids from the product and, therefore, reduce the free water available for microorganisms [6]. In the present study, with the aim of developing antioxidant absorbent pads, hemp cellulose was used as a raw material for the production of aerogels and cryogels produced by supercritical drying and freeze-drying, respectively, which were then impregnated with an antioxidant extract from rice straw. As it is known that supercritical CO2 produces aerogels with hairy beads, men while freeze-drying shoed a sheet-like morphology. Thus, the structure can influence the mechanical properties of the material and the water sorption capacity. The antioxidant extract was obtained as a by-product during the extraction of cellulose from rice straw through alkaline hydrolysis. The antioxidant capacity evaluated as the percentage of β-carotene bleaching inhibition showed high antioxidant activity (50.42%) in contrast to butylated hydroxytoluene (BHT) used as a reference antioxidant (77.96%).</p><p>To evaluate the development of hemp cellulose-based absorbent pads, the obtained aerogels and cryogels were further characterized to understand the effect of the drying method. First, both materials maintained their integrity when immersed in water, indicating that the hydrophobization of the cellulose during oxidation and homogenization was successful. In addition, the water sorption test showed that the cryogels and aerogels were able to absorb approximately 1.9 times their initial weight, indicating that both are good candidates for use as absorbent pads. However, aerogels presented significant shrinkage, when exposed to 100% RH, whereas cryogels remain almost the original size. On the other hand, TGA analysis showed that aerogels exhibited a shift in degradation peaks to higher temperatures. This demonstrates that aerogels have higher thermal stability than cryogels. Similarly, during compression tests aerogels did showed higher values than cryogels in the same compressive deformation percentage, indicating that they are materials with higher resistance. The obtained materials differed in their density, compressibility, and water sorption. In addition, both materials were impregnated with the antioxidant extract, and the antioxidant capacity of the materials was evaluated. Thus, as a result of valorization strategies of hemp logs and rice straw residues, not only a food packaging material was developed but also a potential antioxidant delivery system.</p&gt

BIODEGRADABLE FILMS BASED ON PHBV/PBAT BLENDS AND HEMP FIBERS FOR FOOD PACKAGING APPLICATIONS

<p>Among the food packaging industry requirements, rigid hydrophobic materials are highly demanded. These materials enable the preservation of food products, preventing weight loss while maintaining the package integrity. Research focusing on using biodegradable polymers has increased in light of the growing awareness of environmental pollution and the need to replace conventional plastics by more sustainable materials. A specific area of concern is the selection of materials used in the production of food packaging products, as commonly used plastics contribute significantly to daily waste generation [1]. </p><p>Biodegradable polymers are widely considered as an alternative to conventional plastic-based materials, as these materials would significantly reduce waste accumulation in the environment. For example, the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has attracted significant interest due to its advantageous performance characteristics and relatively lower cost compared to other polymers within the polyhydroxyalkanoates (PHAs) family [2,3]. The synthesis of PHBV involves incorporating poly(3-hydroxyvalerate) (PHV) into the PHB molecule [2-4]. Blending PHBV with other materials can improve the mechanical properties and price of the final product. For instance, a low-cost biodegradable copolymer that can be used in polymeric matrices is the polybutylene adipate terephthalate (PBAT) that is an amorphous copolyester with an aliphatic-aromatic chain formed through polycondensation of 1,4-butanediol with adipic and terephthalic acids [2,5]. PBAT can be incorporated into polymer blends to promote stiffening and improve elongation at break [6]. Although PBAT is not a natural polymer, its biodegradable capability makes it a viable alternative for producing environmentally friendly materials. </p><p>Additionally, natural fibers are renewable, cheap and eco-friendly materials widely available from various vegetal biomasses, such as, wood fibers, jute, miscanthus, sisal, hemp, and flax [2,7], that can be used to develop biodegradable packaging materials. Hemp fiber (Cannabis sativa), is a natural fiber with crystalline cellulose fibrils, is an interesting under-exploited biomass to be used as a source of natural lignocellulosic fibers acting as fillers in polymeric formulation [8]. Extensively grown in Latin America, Europe, and China, hemp fiber possesses a notable content of crystalline cellulose (55-72%), lignin (2-5%), and hemicellulose (8-19%), rendering it highly appealing as a reinforcement material in polymers [7-8].</p><p>This study aimed to produce biodegradable composites focused on the highest possible amount of hemp fibers, which is a low-value residue, and blending it with different concentrations of the biodegradable polymers PHBV and PBAT. With the goal of improve the processability and the hydrophobicity of the composites, natural waxes (beeswax or carnauba wax) were added. The formulations were produced by melt compounding, and films were prepared by compression molding. The concentration of the polymers used showed to be an important element to choose the hemp fiber concentration to be employed. With the waxes addition in the biocomposites, the water vapor barrier properties were improved, and also their hydrophobicity improved by up to 41% in the contact angles results. </p><p>The methodology employed in this study to produce a biocomposite using a mixture of PHBV, PBAT, and the higher possible incorporation of HF has proven to be effective, generating an environmentally friendly material, with good cost-effective and desirable traits that may be suitable for utilization in food packaging.</p&gt

Desarrollar y poner en funcionamiento modelos de demanda y de oferta de transporte, que permitan proponer opciones en materia de infraestructura, para aumentar la competitividad de los productos colombianos.

Propuesta y desarrollo de un método que permite modelar las características asociadas a la movilidad que ocasiona un producto específico (demanda de transporte); en cuanto a la oferta se estandarizo la codificación utilizando como plataforma la base de georreferencia oficial sobre el sistema vial determinada por el IGAC. El modelo de transporte desarrollado, aunque parte de la base del sistema actual, plantea algunos escenarios futuros donde se suponen las características de la demanda por transporte y se ensayan proyectos de infraestructura previstos por las entidades gubernamentales pertinentes, además, permite ser ajustado por los interesados. Es una herramienta tecnológica que permite probar diferentes situaciones en diferentes contextos.IP 1109-327-19588Contrato No. 386-2006;Grupos de investigación: Grupo de investigación y desarrollo e operación y planeación del transporte. GIDPOT. -- Grupo de investigación en vías y transportes. VITRA. -- Grupo de investigacion en transportes y vías. TRANVÍA;Información tomada del informe final preliminar.Informe final preliminar: Modulo 1. Aspectos generales sobre la innovación y el desarrollo tecnológico desarrollados Modulo 2. Impacto del proyecto ;[Anexos]: v.1 Documento A: Resumen ejecutivo (Informe técnico preliminar). -- v.2 Documento C: Definición metodológica del modelo de demanda de carga. / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.3 Documento D: Definición metodológica del modelo de oferta. / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE , Grupo de Investigación TRANVIA. -- v.4 Documento H: Variables socioeconómicas: Datos base y proyecciones. / Víctor Gabriel Valencia Alaix , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.5 Documento I: Matrices origen - Destino. / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.6 Documento J: Flujos de comercio interno y externo. Metodologías e información. / Luis Alfredo Vega Báez , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.7 Documento K: Parque vehicular tipo y embalaje. / Víctor Manuel Cantillo Maza , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.8 Documento L: Carga interna y de comercio exterior - proyecciones. / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.9 Documento M: Modelo de oferta de transporte para Colombia: documento conceptual. / Víctor Manuel Cantillo Maza , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.10 Documento N: Modelo de oferta de transporte para Colombia: selección de información / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.11 Documento O: Modelo de oferta de transporte para Colombia: calibración y asignación / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.12 Documento P: Diagnóstico de la información secundaria. / Luis Alfredo Vega Báez , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.13 Documento Q: Sitios críticos / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.14 Documento R: Corredores de comercio exterior / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.15 Documento S: Centros de transferencia / Luis Gabriel Márquez Díaz, Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.16 Documento T: Necesidades de infraestructura / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.17 Documento U: Modelo de demanda de transporte: aplicativo. / Lucy Esther García Ramos , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.18 Anexo A: Mapas temáticos por departamento. / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.19 Documento B: Informe ejecutivo / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.20 Documento C: Modelo de demanda de transporte para Colombia: Documento conceptual / Víctor Manuel Cantillo Maza , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.21 Documento D: Zonificación / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.22 Documento D: Zonificación Anexo A / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.23 Documento D: Zonificación Anexo B / Luis Gabriel Márquez Díaz , v.24 Documento D: Zonificación Anexo C / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.25 Documento D: Zonificación Anexo D / Luis Gabriel Márquez Díaz , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.26 Documento E: Año base: Metodología para su determinación / Víctor Gabriel Valencia Alaix , Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.27 Documento F: Estudio de productos relevantes: Metodología, bases de datos y descripción / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.28 Documento G: monografías de productos G01 Abonos y fertilizantes / Víctor Manuel Cantillo Maza. … [et al.]. -- v.29 Documento G: monografías de productos G02 Aceites y grasas / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.30 Documento G: monografías de productos G03 Alimentos / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.31 Documento G: monografías de productos G04 Alimentos balanceados para animales / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.32 Documento G: monografías de productos G05 El arroz / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.33 Documento G: monografías de productos G06 El azúcar / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.34 Documento G: monografías de productos G07 Banano / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.35 Documento G: monografías de productos G08 Bebidas Carbón / Víctor Manuel Cantillo Maza. … [et al.]. -- v.36 Documento G: monografías de productos G09 Biocombustibles / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.37 Documento G: monografías de productos G10 El café / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.38 Documento G: monografías de productos G11 Carbón / Víctor Manuel Cantillo Maza. … [et al.]. -- v.39 Documento G: monografías de productos G12 Cemento, cal y yeso / Víctor Manuel Cantillo Maza. … [et al.]. -- v.40 Documento G: monografías de productos G13 Los productos cerámicos / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.41 Documento G: monografías de productos G14 Derivados del petróleo / Víctor Manuel Cantillo Maza. … [et al.]. -- v.42 Documento G: monografías de productos G16 Las flores / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.43 Documento G: monografías de productos G17 Las frutas, excepto el banano / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.44 Documento G: monografías de productos G18 Ganado bovino – porcino / Víctor Manuel Cantillo Maza. … [et al.]. -- v.45 Documento G: monografías de productos G20 La leche / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.46 Documento G: monografías de productos G21 Legumbres y hortalizas / Víctor Manuel Cantillo Maza. … [et al.]. -- v.47 Documento G: monografías de productos G22 La madera / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.48 Documento G: monografías de productos G23 monografia de investigación de la demanda de maíz / Unión Temporal Modelación De Transporte UPTC-UNALMED-UNINORTE. -- v.49 Documento G: monografías de productos G24 Manufacturados / Víctor Manuel Cantillo Maza. … [et al.]. -- v.50 Documento G: monografías de productos G25 Otros / Víctor Manuel Cantillo Maza. … [et al.]. -- v.51 Documento G: monografías de productos G26 Otras harinas / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.52 Documento G: monografías de productos G27 La papa / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.53 Documento G: monografías de productos G28 El papel y el cartón / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.54 Documento G: monografías de productos G29 Paquetes postales / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.55 Documento G: monografías de productos G30 Petróleo crudo / Víctor Manuel Cantillo Maza. … [et al.]. -- v.56 Documento G: monografías de productos G31 La sal / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.57 Documento G: monografías de productos G32 La soya / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.58 Documento G: monografías de productos G33 El trigo / Iván Reinaldo Sarmiento Ordosgoitia. … [et al.] -- v.59 Documento G: monografías de productos G34 Vehículos / Víctor Manuel Cantillo Maza. … [et al.]

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease