On the Performance of Decode-and-Forward Equal-Gain-Combining Relay Systems over Weibull Fading Channels.

Relay-assisted wireless communications, where both the relay and the final destiny employ diversity-combining techniques, represent a compelling strategy for improving the signal-to-noise ratio (SNR) for mobile terminals, mainly at millimeter-wave (mmWave) frequency bands. In this sense, this work considers a wireless network that employs a dual-hop decode-and-forward (DF) relaying protocol, in which the receivers at the relay and at the base station (BS) use an antenna array. Moreover, it is considered that the received signals are combined at reception using equal-gain-combining (EGC). Recent works have enthusiastically employed the Weibull distribution so as to emulate the small-scale fading behavior in mmWave frequencies, which also motivates its use in the present work. For this scenario, exact and asymptotic expressions for the system's outage probability (OP) and average bit error probability (ABEP) are derived in closed form. Useful insights are gained from these expressions. More precisely, they illustrate how the system and fading parameters affect the performance of the DF-EGC system. Monte Carlo simulations corroborate the accuracy and validity of the derived expressions. Furthermore, the mean achievable rate of the considered system is also evaluated via simulations. Useful insights regarding the system performance are obtained from these numerical results.

Determining the environmental and economic implications of lupin cultivation in wheat-based organic rotation systems in Galicia, Spain.

Crop rotation represents a potentially sustainable strategy to address environmental problems of intensive agricultural practices, such as soil degradation, biodiversity reduction, and greenhouse gas emissions. This manuscript assesses the environmental and economic implications of introducing lupin cultivation into winter wheat-based rotation systems under an organic regime in Galicia, Spain. Life Cycle Assessment methodology was used to determine the environmental impacts of three rotation systems over a six-year period: lupin → wheat → rapeseed (OA1), lupin → potato → wheat (OA2), and lupin → wheat → rapeseed ‖ maize (OA3). For a robust assessment, three functional units were applied: land management (ha), economic indicator (gross margin in euros) and protein content (1 kg of protein-corrected grain). Moreover, the environmental profiles were compared with rotation systems without lupin crop in a conventional regime. In terms of Global Warming, impacts of about 2214, 3119 and 766 kg CO2eq·ha-1 were obtained for OA1, OA2 and OA3, respectively. Moreover, OA1 is the best rotation in terms of land and protein. Meanwhile, OA2 rotation is the best choice in the economic function, as it obtained the highest level of gross margin (5708 €·ha-1). Furthermore, with the exception of acidification, organic systems are less impactful than conventional systems. Ammonia emissions from the use of manure are the reason for these higher impacts. Organic rotations OA1 and OA2 have about 6 % or 15 % less gross margin than their conventional counterparts, respectively, however, an increase of 28 % was obtained for rotation OA3. This study helps decision-makers to implement environmentally and economically viable strategies.

Introducing lupin in autochthonous wheat rotation systems in Galicia (NW Spain): An environmental and economic assessment.

Crop diversification, as a sustainable land management practice, is a potential strategy to face soil degradation, climate change and food security, being the incorporation of legumes in cereal rotation systems, a strategy that improves soil nutrient levels. In a context of sustainable agriculture, this manuscript aims to evaluate the effect of lupin cultivation from an environmental and economic perspective in Galician winter wheat-based rotation systems. The life cycle analysis (LCA) methodology was applied for three rotation systems over a six-year period: lupin + wheat + oilseed rape (RA1), lupin + potato + wheat (RA2), and lupin + wheat + oilseed rape + maize (RA3). The general approach of this study was to collect primary data associated with the rotation crops to quantify their environmental impacts and economic benefits and to identify their advantages or disadvantages. Comparing and contrasting the environmental profiles based on three functional units: hectare land (ha), financial indicator (gross margin, €) and yield production (kg of wheat grain) allows a robust evaluation of each crop rotation system. Relating to rotations without lupin, the results indicate that for the impact categories evaluated, the introduction of lupin proved to be favourable with notable reductions of 64% and 30% in the environmental categories of Global Warming and Marine Eutrophication, respectively. Moreover, favourable economic consequences were evident in rotations RA1 and RA2 with a 19% and 51% increase in financial indicators, respectively, but with a marginal reduction of 2% in gross margin in RA3. This study motivates stakeholders to understand the environmental impacts of diversification strategies in agricultural systems and serves as a baseline to address the assessment of the social aspects of these systems for a complete sustainability perspective.

Cultural Context or Generational Cohort: Which Influences Tourist Behavior More?

According to most academics, different generations share common characteristics. This undoubtedly helps to better understand their behavior in different scenarios, predicting their responses. However, this seems questionable and that is the main purpose of this study. This research, although preliminary, try to confirm if millennials have common characteristics, or if, on the contrary, there are differences between them due to the culture in which they are immersed. To this end, it has been contextualized in a sector that is very sensitive to cultural differences, such as tourism. Data collection was carried out through a questionnaire administered in 2019 via e-mail to young South Korean and Spanish millennials (born 1982-2002). The results suggest that there do not appear to be common personality traits between the countries analyzed. The differences between the two groups for most personality traits and travel motivations were significant. The findings of this research provide several practical implications since it will make possible a more appropriate management of the tourist destination.

Environmental consequences of wheat-based crop rotation in potato farming systems in galicia, Spain.

Intensive agricultural farming systems have negative impacts on the ecosystem. Therefore, the use of crop rotation emerges as an opportunity to improve the environmental sustainability of agricultural systems. In the region of Galicia in north-western Spain, potato and wheat are important commodities and essential foods in the diet. Hence, it is interesting to investigate the environmental profile of these crops to improve the understanding of local agrosystems. This study evaluated three agricultural crops managed under a crop rotation system and following a conventional arable farming: the main rotation crop, which is the potato in the first year (cP), followed by a second year of commercial wheat (cW) and autochthonous Galician wheat (GcW) in the third year. The Life Cycle Assessment (LCA) methodology was performed using four types of functional units: in terms of productivity (kg-1); land management (ha-1∙year-1); a financial function (euros €-1 of income from sales) and energetic value (MJ-1). The environmental indicators selected are Climate Change (CC), Particulate Matter (PM), Terrestrial Acidification (TA), Freshwater Eutrophication (FE), Marine Eutrophication (ME), Human Toxicity (HT), Land Use (LU) and Fossil Depletion (FD). The figures show that the GcW has the lowest environmental impact when the functional units refer to land management, financial function and energetic value. However, if analysed in terms of productivity, cP is presented as the best crop due to its comparatively higher yield, reaching a production ratio 10 times higher than wheat. In the specific case of wheat, compared to a previous study in the same region, the environmental impacts are lower when grown in a crop rotation system in contrast to monoculture. This article demonstrates the relevance of using LCA for diverse stakeholders (e.g., farmers, consumers and researchers) to understand the environmental impacts of regional agricultural systems. In addition, it serves as a basis for future work aimed at comparing rotational agricultural systems in this region, integrating economic and social aspects.

New perspectives on satisfaction and loyalty in festival tourism: The function of tangible and intangible attributes.

This research explains how attributes perceived during the festival celebration generate loyalty in terms of satisfaction. As regard, tangible aspects (festival entertainment and aesthetics) and intangible aspects (escapism and education) shall be differentiated. A theoretical model is proposed, which explains the effects of festival attributes on satisfaction and loyalty through structural equation modelling. The model was estimated with a sample of 440 people attending Weekend Beach Festival in Spain. The research proves the relationship between attributes and loyalty through satisfaction as a moderating variable; likewise, tangible attributes are deemed to have a greater influence on loyalty, specifically, the aesthetic/environment experience.

Life cycle assessment of autochthonous varieties of wheat and artisanal bread production in Galicia, Spain.

For millennia, bread and wheat have been one of the most important sources of nutrients in many civilizations. Today, mechanization and evolution in agriculture and food processing have intensified yields and modified the biological and nutritional aspects of multiple crops and foods. The Galician bread is a reference value of food heritage in Spain, which is made from common wheat grain and is a mixture of indigenous Galician wheat and conventional Spanish wheat. In the pursuit of product excellence, it is interesting to identify the environmental profile as support criteria in decision-making, not only to analyse product environmental sustainability, but also as a marketing element to improve consumer awareness. The paper has a twofold perspective to analyse the environmental burdens of wheat cultivation and the bread sector, using life cycle assessment approach: 1) the comparison of the different types of agricultural systems, i.e. the cultivation of Galician wheat following a strategy of monoculture and crop rotation, certified Galician seed production and its comparison with conventional wheat cultivation and 2) the environmental profile of Galician bread. The functional units chosen were 1 kg of wheat grain transported to the milling facility and 1 kg of Galician bread. The results show that wheat cultivation presents the main environmental impacts of bread production, mainly due to the use of agrochemicals and field emissions. The best cultivation scenario corresponds to a crop rotation system, since chemical fertilisation is not applied. In comparative terms with many staple foods produced in Europe, Galician bread has a low environmental impact. The overall environmental results of bread production draw attention to the dependence of bread and flour manufacturers on the agricultural sector, highlighting the need to share responsibilities across the supply chain. In addition, this study contributes to the stakeholder debate on environmental impacts related to food heritage.