Economic viability and optimization of solar microgrids with hybrid storage in a non-interconnected zone in Colombia

Environment, Development and Sustainability - A developing country that does not have adequate energy solutions in non-interconnected zones (ZNIs) undoubtedly experiences adverse effects in terms...     

Minimizing disruptions caused by damming and ensuring the health of downstream ecosystems

In view of the Brazilian Ten‐Year Energy Expansion Plan 2021, this article presents a discussion on environmental flow (e‐flow). The authors analyze the literature to show the evolution of publications concerning e‐flow releases from the perspective of ecosystems services preservation considering results from different case studies from throughout the world. Finally, two main recommendations are drawn regarding e‐flow are: (1) performing a holistic approach to e‐flow planning, including hydrological, hydraulic, water quality, habitat, and riparian zone considerations; and (2) installing in new structures adequate bottom outlets to allow a range of adjustable e‐flow from reservoir dams to reproduce natural flow variations.     

Overview of surface measurements and spatial characterization of submicrometer particulate matter during the DISCOVER-AQ 2013 campaign in Houston,TX

The sources of submicrometer particulate matter (PM₁) remain poorly characterized in the industrialized city of Houston, TX. A mobile sampling approach was used to characterize PM₁ composition and concentration across Houston based on high-time-resolution measurements of nonrefractory PM₁ and trace gases during the DISCOVER-AQ Texas 2013 campaign. Two pollution zones with marked differences in PM₁ levels, character, and dynamics were established based on cluster analysis of organic aerosol mass loadings sampled at 16 sites. The highest PM₁ mass concentrations (average 11.6 ± 5.7 µg/m³) were observed to the northwest of Houston (zone 1), dominated by secondary organic aerosol (SOA) mass likely driven by nighttime biogenic organonitrate formation. Zone 2, an industrial/urban area south/east of Houston, exhibited lower concentrations of PM₁ (average 4.4 ± 3.3 µg/m³), significant organic aerosol (OA) aging, and evidence of primary sulfate emissions. Diurnal patterns and backward-trajectory analyses enable the classification of airmass clusters characterized by distinct PM sources: biogenic SOA, photochemical aged SOA, and primary sulfate emissions from the Houston Ship Channel. Principal component analysis (PCA) indicates that secondary biogenic organonitrates primarily related with monoterpenes are predominant in zone 1 (accounting for 34% of the variability in the data set). The relevance of photochemical processes and industrial and traffic emission sources in zone 2 also is highlighted by PCA, which identifies three factors related with these processes/sources (~50% of the aerosol/trace gas concentration variability). PCA reveals a relatively minor contribution of isoprene to SOA formation in zone 1 and the absence of isoprene-derived aerosol in zone 2. The relevance of industrial amine emissions and the likely contribution of chloride-displaced sea salt aerosol to the observed variability in pollution levels in zone 2 also are captured by PCA.

Implications: This article describes an urban-scale mobile study to characterize spatial variations in submicrometer particulate matter (PM₁) in greater Houston. The data set indicates substantial spatial variations in PM₁ sources/chemistry and elucidates the importance of photochemistry and nighttime oxidant chemistry in producing secondary PM₁. These results emphasize the potential benefits of effective control strategies throughout the region, not only to reduce primary emissions of PM₁ from automobiles and industry but also to reduce the emissions of important secondary PM₁ precursors, including sulfur oxides, nitrogen oxides, ammonia, and volatile organic compounds. Such efforts also could aid in efforts to reduce mixing ratios of ozone.     

Estimating dyad association probability under imperfect and heterogeneous detection

In animal behaviour studies, association indices estimate the proportion of time two individuals (i.e. a dyad) spend in association. In terms of dyads, all association indices can be interpreted as estimators of the probability that a dyad is associated. However, traditional indices rely on the assumptions that the probability to detect a particular individual (p) is either approximately one and/or homogeneous between associated and not associated individuals. Based on marked individuals we develop a likelihood based model to estimate the probability a dyad is associated (ψ) accounting for p < 1 and possibly varying between associated and not associated individuals. The proposed likelihood based model allows for both individual and dyadic missing observations. In addition, the model can easily be extended to incorporate covariate information for modeling p and ψ. A simulation study showed that the likelihood based model approach yield reasonably unbiased estimates, even for low and heterogeneous individual detection probabilities, while, in contrast, traditional indices showed moderate to strong biases. The application of the proposed approach is illustrated using a real data set collected from a population of Commerson's dolphin (Cephalorhynchus commersonii) in Patagonia Argentina. Finally, we discuss possible extensions of the proposed model and its applicability in animal behaviour and ecological studies.     

Sustainable development in the BRICS countries: an efficiency analysis by data envelopment

There is much concern about the social and environmental impacts caused by the economic growth of nations. Thus, to evaluate the socio-economic performance of nations, economists have increasingly addressed matters related to social welfare and the environment. It is within the scope of this context that this work discusses the performance of countries in the BRICS group regarding sustainable development. The objective of this study regards evaluating the efficiency of these countries in transforming productive resources and technological innovation into sustainable development. The proposed objective was achieved by using econometric tools as well as the data envelopment analysis method to then create economic, environmental, and social efficiency rankings for the BRICS countries, which enabled to carry out comparative analyses on the sustainable development of those countries. The results of such assessments can be of interest for more specific scientific explorations.     

Niche segregation in sandy beach animals: an analysis with surface-active peracarid crustaceans on the Atlantic coast of Spain

Several species of sandy beach invertebrates regularly switch between burial in the sand during the day and surface activity at night to feed on stranded organic matter. Because all species consume essentially the same type of food (i.e., wrack) deposited over a restricted area, the potential for competition exists. Conversely, spatial and temporal segregation of surface activity behaviour is predicted to allow for niche separation. Here, we tested whether such behavioural niche separation occurs in three species of sympatric crustaceans (the talitrid amphipods Talitrus saltator (Montagu 1808) and Talorchestia brito Stebbing 1891, and the oniscoidean isopod Tylos europaeus Arcangeli 1938). We also assessed whether surface activity is modulated by weather, sea conditions and moon phases. Surface activity was measured over three consecutive moon phases on an exposed beach on the Atlantic Coast of Spain using pitfall traps along three transects from the foredunes to the swash. Adults of the amphipod T. saltator and the isopod T. europaeus overlapped spatially and temporally in their surface activity for most of the night. By contrast, the activity of T. brito was strongly disjunct in time and concentrated into significantly shorter bouts around dawn or dusk. Niche differentiation was also evident along the space axis, where T. brito occurred distinctly lower on the beach. Although several environmental factors (e.g., air and sand temperature, humidity, atmospheric pressure, wind speed and wind direction) were correlated with surface activity, this was highly variable amongst species, life stages, and synodic phases, and did not obscure the fundamental mosaic of spatio-temporal heterogeneity amongst species. Nocturnal feeding on beach wrack creates the potential for competition amongst sympatric crustaceans which can, however, be mitigated by behaviour patterns that separate consumers in time and space.     

Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems: a spatial approach

The introduced feral cat (Felis catus) is a widespread generalist with flexible social behaviour and an apex predator without major interspecific competitors in insular ecosystems that evolved in the absence of predators. Mechanistic definitions consider an animal’s home range to be the spatial expression of a cognitive map that is kept up-to-date with the status of critical resources that contribute to animal fitness. We assumed there are two major determinants structuring the home range of cats as apex predators in insular ecosystems: the distribution of critical food resources and conspecific distribution. We hypothesized that cats structure their home ranges by optimizing the use of staple critical food resources and that as a consequence of the presence of rich resources cats tend to socialise, aggregate and share space. We carried out spatial analyses using location data for feral cats tracked using lightweight GPS collars in conjunction with the suitability value of rabbit patches and their associated ownership costs for cats within a New Zealand braided-river environment. Cat home ranges and spatial distribution, especially for females, were related to the inclusion of rabbit patches within home ranges with higher mean value than the average of neighbourhood patches in the landscape. Cats showed solitary behaviour but tolerance to conspecific presence by sharing high-use areas and high-value rabbit patches, mostly at different times, resulting in occasional encounters among males and females. Home range size and patterns of spatial overlap were dependant on sex and season. Solitary spacing patterns as consequence of innate preferences together with resource constraints may regulate feral cat population densities.     

Transport of Sewage Sludge in a Mixed Water Column

Abstract

Sewage sludge from four publicly-owned treatment works was sampled and characterized in terms of parameters affecting transport at the 106-mile deep ocean disposal site as part of the US Environmental Protection Agency's site monitoring programme. Samples from treatment plants in Passaic Valley, Rahway, and Elizabeth, New Jersey and New York City were characterized in terms of dynamic size distribution, suspended solids and density. the transport characteristics of sludge particles were measured using a 2 metre computer-interfaced laboratory settling column. Experiments were conducted at constant salinity (35 ppt) while varying hydrodynamic mixing, sludge type and concentration using a modified factorial experimental design. Hydrodynamic power dissipation was varied so that the vertical dispersion and rms fluid shear rate ranged between 0-6 cm²S^?1 and 0-30s^?1 respectively. Results indicate that at least 80% of suspended sludge particles will eventually settle under mixed conditions. the average settling velocities ranged between 0.05-4.05 × 10^-3 cm ^s-1. Shear rates above 15 s^?1 inhibited sludge settling due to aggregate breakup and boundary effects, but at a lower shear rate, differential settling and fluid shear were the dominant transport mechanisms. Sludge dilution (1/500-1/5000) had a limited effect on the settling rate. Results from this study can be used to calibrate particle transport models to determine the fate of sludge disposed at an ocean disposal site.     

Tillage system did not affect weed diversity in a 23-year experiment in Mediterranean dryland

This study investigated whether the choice of a tillage system (no-tillage, minimum tillage or traditional tillage) affected weed diversity in a 23 years cereal–leguminous rotation system in Spain. Weed diversity was assessed using common diversity indices: species richness, Shannon's index and Pieloús evenness. Linear mixed-effects models were employed to compare the tillage systems. It was found that after 23 years no large differences between tillage systems have arisen related to weed diversity. Only minimum tillage appeared to support, on average, more species than the two other tillage systems. Richness, Shannon diversity index and evenness varied largely through the years in all tillage systems but this variation was not related to type of crop sown (cereal or leguminous). Our results highlight that conservation tillage practices did not represent any concern for weed diversity conservation in cereal–leguminous rotations in the conditions of central Spain.