The Role of Small and Medium Enterprises in Development of Tourism in a Post-war Context: the Case of Angola

ost-war countries face a challenge in the process of re-entering the tourism market for several reasons. The damages caused by the violent war environment create the challenges of restoring their image, their economy and of asserting security. As a result, post-war countries have limited monetary resources for development. For this reason, they turn to tourism to help in their development and utilise Small and Medium Enterprises (SMEs) in the process to establish the foundations for tourism development. SMEs play an important role in the development process because they provide products and services and create jobs. This study explores the factors related to developing tourism in a post-war context, along with the importance of SMEs in this process. Angola is used as case study of a post-war country that has great potential, yet remains unable to compete effectively as an attractive tourism destination.&nbsp

Life Cycle Assessment of Alkali Activated Cement compared to Ordinary Portland Cement

Approximately 8% of the global emissions of CO2 are originated by the cement industry, which consumes on average between 4 to 6 GJ per ton of cement. Ordinary Portland Cement (OPC) is the most used cement for construction purposes. Every year, around 4 billion tonnes (Gt) of OPC are manufactured. For each kg of OPC produced, 0.81 kg of CO2 is generated. Therefore, seeking cements with more environmentally friendly manufacturing process, economically viable, and socially relevant is necessary. One of the most promising materials are the Alkali-Activated Cements (AAC), where its components are an aluminosilicate precursor and alkaline activators. The precursor used in this study is Weathered Bottom Ash (WBA), a waste obtained from the Municipal Solid Waste Incineration (MSWI). On the other hand, the alkaline activators are sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The name of the AAC developed is Sustainable-AAC (Sust-AAC). This project is focused on searching for new materials that could reduce the use of OPC as a building material. To be able to assess the associated environmental impacts, a comparison between AAC and OPC (CEM I) through a Life Cycle Assessment (LCA) following the standards ISO 14040:2006 and ISO 14044:2006 is performed. The LCA methodology allows identification and quantification of relevant inputs and outputs of the system, thus, evaluating the potential environmental impacts associated. The system boundary of this project is cradle-to-gate and the functional unit of the assessment is 1 ton of commercial cement. The OPC inventory is carried out through the values obtained in GaBi Software and the Sust-AAC inventory is made from the previous studies performed in the DIOPMA research group, on a laboratory scale. The results show that the OPC has higher impact on global warming, energy consumption, water consumption, and mineral extraction categories compared to Sust-AAC. In OPC manufacturing, the kiln stage is the most energy intensive stage (by the chemical reaction and by the fossil fuel requirement) and therefore, has the most significant environmental impact in terms of CO2 emissions and energy consumption. In contrast, the highest environmental impacts on the Sust-AAC are due to the production of Na2SiO3. The main reason for the energysaving is because Sust-AAC production does not need a kiln with high temperatures. In addition, the use of waste as raw material promotes a circular economy and, at the same time, reduces the extraction of natural resources. Then, the environmental performance in the Sust-AAC is promising compared to OPC. Sust-AAC is suitable to be used as lightweight material and as insulation material for thermal insulating applications. This application can contribute to realising operational energy savings and performance benefits

Geopolymers based on the valorization of Municipal Solid Waste Incineration residues

he proper management of Municipal Solid Waste (MSW) has become one of the main environmental commitments for developed countries due to the uncontrolled growth of waste caused by the consumption patterns of modern societies. Nowadays, municipal solid waste incineration (MSWI) is one of the most feasible solutions and it is estimated to increase in Europe where the accessibility of landfill is restricted. Bottom ash (BA) is the most significant by-product from MSWI as it accounts for 85-95 % of the solid product resulting from combustion, which is classified as a non-hazardous residue that can be revalorized as a secondary aggregate in road sub-base, bulk lightweight filler in construction. In this way, revalorization of weathered BA (WBA) for the production of geopolymers may be a good alternative to common reuse as secondary aggregate material; however, the chemical process to obtain these materials involves several challenges that could disturb the stability of the material, mainly from the environmental point of view. Accordingly, it is necessary that geopolymers are able to stabilize heavy metals contained in the WBA in order to be classified as non-hazardous materials. In this regard, the SiO2/Al2O3 ratio plays an important role for the encapsulation of heavy metals and other toxic elements. The aim of this research is to formulate geopolymers starting from the 0-2 mm particle size fraction of WBA, as a unique raw material used as aluminumsilicate precursor. Likewise, leaching tests of the geopolymers formulated were performed to assess their environmental impact. The findings show that it is possible to formulate geopolymers using 100 % WBA as precursor, although more investigations are needed to sustain that geopolymer obtained can be considered as non-hazardous materials

Validating a traffic conflict prediction technique for motorways using a simulation approach

With the ever-increasing advancements in the technology of driver assistant systems, there is a need for a comprehensive way to identify traffic conflicts to avoid collisions. Although significant research efforts have been devoted to traffic conflict techniques applied for junctions, there is dearth of research on these methods for motorways. This paper presents the validation of a traffic conflict prediction algorithm applied to a motorway scenario in a simulated environment. An automatic video analysis system was developed to identify lane change and rear-end conflicts as ground truth. Using these conflicts, the prediction ability of the traffic conflict technique was validated in an integrated simulation framework. This framework consisted of a sub-microscopic simulator, which provided an appropriate testbed to accurately simulate the components of an intelligent vehicle, and a microscopic traffic simulator able to generate the surrounding traffic. Results from this framework show that for a 10% false alarm rate, approximately 80% and 73% of rear-end and lane change conflicts were accurately predicted, respectively. Despite the fact that the algorithm was not trained using the virtual data, the sensitivity was high. This highlights the transferability of the algorithm to similar road networks, providing a benchmark for the identification of traffic conflict and a relevant step for developing safety management strategies for autonomous vehicles

Electron microscopy analysis of ATP-independent nucleosome unfolding by FACT

FACT is a histone chaperone that participates in nucleosome removal and reassembly during transcription and replication. We used electron microscopy to study FACT, FACT:Nhp6 and FACT:Nhp6:nucleosome complexes, and found that all complexes adopt broad ranges of configurations, indicating high flexibility. We found unexpectedly that the DNA binding protein Nhp6 also binds to the C-terminal tails of FACT subunits, inducing more open geometries of FACT even in the absence of nucleosomes. Nhp6 therefore supports nucleosome unfolding by altering both the structure of FACT and the properties of nucleosomes. Complexes formed with FACT, Nhp6, and nucleosomes also produced a broad range of structures, revealing a large number of potential intermediates along a proposed unfolding pathway. The data suggest that Nhp6 has multiple roles before and during nucleosome unfolding by FACT, and that the process proceeds through a series of energetically similar intermediate structures, ultimately leading to an extensively unfolded form

MicroRNAs, miR-154, miR-299-5p, miR-376a, miR-376c, miR-377, miR-381, miR-487b, miR-485-3p, miR-495 and miR-654-3p, mapped to the 14q32.31 locus, regulate proliferation, apoptosis, migration and invasion in metastatic prostate cancer cells

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