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This article presents a novel centrality-driven gateway designation framework for the improved real-time performance of low-power wireless sensor networks (WSNs) at system design time. We target time-synchronized channel hopping (TSCH) WSNs with centralized network management and multiple gateways with the objective of enhancing traffic schedulability by design. To this aim, we propose a novel network centrality metric termed minimal-overlap centrality that characterizes the overall number of path overlaps between all the active flows in the network when a given node is selected as gateway. The metric is used as a gateway designation criterion to elect as a gateway the node leading to the minimal number of overlaps. The method is then extended to multiple gateways with the aid of the unsupervised learning method of spectral clustering. Concretely, after a given number of clusters are identified, we use the new metric at each cluster to designate as cluster gateway the node with the least overall number of overlaps. Extensive simulations with random topologies under centralized earliest-deadline-first (EDF) scheduling and shortest-path routing suggest our approach is dominant over traditional centrality metrics from social network analysis, namely, eigenvector, closeness, betweenness, and degree. Notably, our approach reduces by up to 40% the worst-case end-to-end deadline misses achieved by classical centrality-driven gateway designation methods. This work was partially supported by National Funds through FCT/MCTES (Portuguese Foundation for Science and Technology), within the CISTER Research Unit (UIDB/04234/2020); by the Operational Competitiveness Programme and Internationalization (COMPETE 2020) under the PT2020 Agreement, through the European Regional Development Fund (ERDF); also by FCT and the ESF (European Social Fund) through the Regional Operational Programme (ROP) Norte 2020, under PhD grant 2020.06685.BD.

Individual tree species might affect underground soil properties to favor the decomposition of their own litter. However, in some studies, monospecific litter decomposed faster underneath multispecific canopies than under canopies of the same species as the litter, suggesting that plant diversity in the overstorey creates a more favorable decomposition microenvironment. We compared the decomposition rate of monospecific litter from eight temperate tree species under the crown of the same species as the litter (conspecific canopy), and a multispecific canopy formed by eight species. Using model selection, we determined the influence of the microenvironments, species, and litter chemistry on decomposition rates. The most robust model included the species and canopy type, but it differed only slightly from the model including only the species. Decomposition rates were significantly different among species and higher in conspecific canopy than multispecific canopy in all species. Models including specific leaf area and different combinations of chemical traits of the litter were less robust than the null model. These results show that the species origin of the litter was significantly more important than the microenvironment to explain litter decomposition rates.

ABSTRACT: Small-scale farmers are essential food suppliers, especially in developing countries, but they face many constraints that limit their productivity and returns. Associating with other farmers (for instance, through cooperatives) has been shown to be a strategy to mitigate these constraints; however, there are limitations in farmers’ participation and commitment to associations. This research explored small-scale farmers’ attitudes and perceptions of associations. This paper considered the district of Cauquenes, a rural area in central Chile. A total of 71 small-scale farmers were surveyed. The data were processed using descriptive, multivariate, and qualitative techniques. The results showed that the farmers had limited knowledge of and experience with associations. They also did not see participation in an association as necessary for improving their business outcomes. They were also reluctant to accept a possible loss in decision-making power or the possibility of being scammed or tricked. The factors underlying farmers’ attitudes toward associations were “Uncertainty of economic benefits” (23.3% of variance), “Technical-economic limitations perception” (15.2%), “Distrust” (10.8%), and “Individualism” (9.8%). These results suggested that policies are needed to improve farmers’ experience with and knowledge of associations, considering the cultural variables that affect distrust and focusing on existing uncertainties. The associative processes need to allow for progressive commitment, expedite tangible results, and provide continuous technical and motivational support. RESUMO: Os pequenos agricultores são essenciais para o abastecimento de alimentos, especialmente nos países em desenvolvimento, mas enfrentam muitas restrições que limitam sua produtividade e retorno. A associação com outros agricultores (por exemplo, por cooperativas) tem se mostrado uma estratégia para mitigar essas deficiências, no entanto, há entraves na participação e comprometimento dos agricultores com as associações. O objetivo desta pesquisa é explorar as atitudes e percepções dos pequenos agricultores em relação às associações. Para isso, consideramos o caso do distrito de Cauquenes, uma área rural no centro do Chile, em que se entrevistou um total de 71 pequenos agricultores. Os dados foram processados por meio de técnicas descritivas, multivariadas e qualitativas. Como resultados, os agricultores têm um conhecimento e experiência limitados sobre as associações e, além disso, não entendem a relevância do vínculo social como uma alternativa para melhorar o seu desempenho. Por outro lado, relutam em uma possível perda de poder decisório, bem como em serem enganados. Os fatores subjacentes às atitudes dos agricultores em relação às associações foram “incerteza dos benefícios econômicos” (23,3%), “percepção de limitações técnico-econômicas” (15,2%), “desconfiança” (10,8%) e “individualismo” (9,8%). Esses resultados nos demonstram serem necessárias políticas que promovam o conhecimento direto, concreto e experiencial dos agricultores sobre o associativismo, com foco nas incertezas existentes. Os processos associativos devem estar atrelados a compromissos progressivos, com foco em resultados tangíveis e suporte contínuo, não apenas técnico, mas também motivacional.

With the aim of contributing to the understanding of plants’ multifunctionality for sustainable agroecosystem management, the first part of this paper addresses the importance of functional biodiversity in the design of agroecological systems, including the local context in the generation of situated knowledge. The second part describes three participatory research experiences with local farmers across three locations in Chile. The first experience reports on the use of Dasyphyllum diacanthoides (endemic tree) as fodder. A second experience focuses on the establishment of Rosa spp. (invasive species) as an agroforestry system integrated into the landscape. Both experiences were collaborative efforts with farmer communities of the Andean Mountains in southern Chile. The final experience describes the use of different spontaneous aromatic and medicinal plants through biological corridors to encourage beneficial insects as natural controllers. All three research experiences reveal a lack of knowledge, decontextualization, and undervaluation of the biocultural diversity present in some traditional Chilean agroecosystems.

The global use of pesticides, exceeding 4 million tons annually, poses substantial threats to public health and the environment. Numerous studies emphasize the correlation between pesticide exposure, genotoxicity, and neurobehavioral effects, which particularly impact children and agricultural workers. Recent research underscores the health risks associated with moderately toxic pesticides like chlorpyrifos. Chlorpyrifos contamination in crops, a result of extensive pesticide use since the 1960s, raises significant concerns regarding human health and the environment. Given its potential atmospheric volatilization from crops, alternative detection methods are imperative. This study employs gas chromatography coupled with mass spectrometry (GC/MS) in MS/MS mode, focusing on detecting chlorpyrifos in Chilean lettuce, using insects as indicators. Two extraction methods, micro-QuEChERS and HEADSPACE-SPME, were compared, with HEADSPACE-SPME demonstrating superior sensitivity (6.77 ng/mg per sample vs. 3.99 ng/mg per sample) and offering time- and solvent-saving advantages. Additionally, HEADSPACE-SPME preserves samples for future research, enhancing its utility. The study confirms the presence of pesticide residues in insects from lettuce crops, with 52.3% displaying chlorpyrifos when the SPME method was used. Predatory and parasitoid insect families like Braconidae and Ichneumonidae show high pesticide loads. The findings of this study emphasize the widespread contamination of chlorpyrifos in lettuce crop insects and highlight the efficacy of SPME for detection, suggesting its broader applicability for evaluating pesticide residues in horticultural systems. This optimized method holds promise for advancing chlorpyrifos contamination detection in agroecosystems, contributing to environmental monitoring and food security.

Imaginaries serve as the foundational framework shaping representations and influencing societal perspectives, subsequently guiding specific practices. Within the realm of geographical imaginaries, this article adopted a geohistorical perspective, using periodicals, secondary sources, and contemporary digital media to shed light on the geography of the highlands of northern Chile. Our objective was to emphasize the representations that have discouraged the occupation of these mountainous regions. Our findings revealed the emergence of a geographic imaginary that attributes desert-like qualities to the entire northern region of Chile, extending beyond the “unpopulated area of Atacama”. This misleading characterization fails to distinguish desert areas from the topographic variations existing between the Andes and the Pacific coast. These representations, which have translated into depopulation practices, have stigmatized the highland areas as synonymous with desolation and inhospitality, seemingly unsuitable for daily life, social production, and reproduction potential. Consequently, both spaces and individuals have been objectified for development, perpetuating the capitalist system as the dominant mode of production.

One current global problem is the shrinkage of rural areas, which is expected to become an increasingly recurrent dynamic caused by the transformations in land uses and forms of habitation of the contemporary era. Patagonia is a suitable case study to understand the processes and challenges exposed by rural shrinkage, which not only addresses population loss but also the causes and consequences that transform rural territories. Its remote geographical location and climate conditions make it a complex place for human settlement. The objective is to describe the relationship between the agrarian structure and rural population decline in Chilean Patagonia. Taking a mixed methodological approach that combines the geohistorical review of settlement processes and the use of statistical procedures with census data, the presence of significant inequalities in the distribution of land and the accumulation of areas in large properties is discussed. The loss of rural population was identified, which may be driven by unequal access to land favoring concentration for extractive activities such as large-scale sheep farming, hydrocarbons and biofuels production. This prompts the exodus of young people to urban centers in search of work and education because land grabbing limits economic options, and rural depopulation reduces service coverage without timely responses from political institutions. This has caused the rural shrinkage in territories with demographic imbalances, with high aging and masculinization rates that hinder the repopulation of these areas, which have historically suffered from underpopulation. In conclusion, population strategies in these areas based on extractivism and a strict land ownership regime have not facilitated permanent human settlement but have instead complicated it more.

Appraising and protecting forests requires a management plan and the creation of innovative products for the market. The development of the green gluing technique could add value to native timber. However, there is a lack of knowledge concerning the response and the productive process of Nothofagus species using this technique. This work investigated the viability of implementing the green gluing method using three types of Nothofagus. Wood pieces were made using a one-component polyurethane adhesive. Delamination, shear tests, morphological characterization, and bond line thickness analysis tested their capacity. The results showed a variable response depending on the Nothofagus type, where the surface treatment could improve the green gluing performance. The findings highlight the relevance of increasing knowledge about the essayed species and their preparation to maintain their natural moisture condition.