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Understanding the trophic interactions and coexistence processes among waterbirds in floodplain ecosystems is of fundamental ecological importance. In the upper Paraná River floodplain, we assessed the diet of five sympatric waterbird species (Ardea alba, Ardea cocoi, Egretta thula, Nannopterum brasilianum, and Nycticorax nycticorax) and tested their differences in the diet, in addition to food overlap, differences in trophic niche breadths and stratum in the water column where they forage. The waterbirds' stomachs were collected quarterly on the upper Paraná River floodplain, analyzed under a stereomicroscope, and the food items were identified. Only Egretta thula was classified as omnivorous, consuming various food resources, including insects, decapods, and fish. The other species were piscivorous, but differed in the types of prey. Food overlap was higher in the piscivorous species, but they exhibited high trophic niche breadth. The piscivorous waterbirds employ different strategies for exploiting food resources that allow species coexistence in the floodplain, avoiding direct competition. Our results highlight the importance of waterbirds as connectors across diverse environments, especially aquatic-terrestrial ecosystems. Since these waterbirds' diet relies on fish, effective conservation and management strategies targeting fish communities are fundamental to maintaining biodiversity and functionality within the upper Paraná River floodplain. [ABSTRACT FROM AUTHOR]

Sustainable development assessments in hydrographic sub-basins are powerful tools used to guide stakeholders. However, there remains a gap in incorporating new indicators (e.g., biodiversity indicators) into sustainability indexes, which have generally underestimated the environmental dimension. We propose an update to these indexes by incorporating biodiversity data on hydrographic sub-basins. Our goal was to introduce a new ecological sustainability index for hydrographic sub-basins (ESI-sb) that utilizes aquatic ecological indicators. We selected 16 indicators and aggregated them into four sustainability dimensions: economic, social, eco-environmental and negative environmental. We used a multi-criteria analysis based on the analysis hierarchy process (AHP) method to catch stakeholders' importance level of each indicator. The ESI-sb was calculated using the weighted average between the sub-indexes that represent the dimensions. Finally, we applied Gi* statistics to identify the ecological sustainability hotspots and coldspots regions, and the results showed in the Serra do Mar region, the southern region, and the Federal District had high ecological sustainability values; meanwhile, the hydrographic sub-basins that formed the coldspot clusters were located in the western region of the Upper Paraná River basin. The incorporation of aquatic biodiversity data into the index represents an innovation in sustainability indexes recently proposed to hydrographic sub-basins. [ABSTRACT FROM AUTHOR]

Quasi-static transition failures in the main logic of modern semiconductors devices are very challenging to be detected in a standard test production environment, because they need a lot of test time to be activated, and usually this is not compatible with a reasonable test time. Many semiconductor manufacturers usually agree not to test these process marginalities to avoid increasing the total cost of the device so much, but accept a few ppm of returns from the customer. In general we are talking about a few decimals of ppm. The typical cases that we can encounter are retention failures in flip-flops, unexpected set, or reset happening after tens of milliseconds. The aim of this work is to discuss the technique/method to deal with quasi-static transition failures. The paper also proposes one possible strategy to detect and locate them in a failure analysis test environment making a benchmark between the most appropriate fault localization technique. [ABSTRACT FROM AUTHOR]

Goats are often affected by respiratory diseases and, despite ultrasonography can assess lung consolidations in several species, it is rarely used in these animals. So, this study evaluated the effectiveness of on-farm lung ultrasonography in detecting lung consolidations on 27 goats. The goats, scheduled for slaughter, underwent complete clinical examinations and lung ultrasonography. For the latter, both sides of the thorax were divided in four quadrants and examined using convex and linear probes before and after shaving the hair. Each quadrant was classified based on presence/absence of lung consolidation and maximum consolidation's depth (4-point scale: 0 healthy; 1 depth < 1 cm; 2 depth < 3 cm; 3 depth > 3 cm). The lungs were examined at necropsy, 66% of goats exhibited lung consolidations and sensitivity (83%-89%), specificity (100%), and κ coefficient values (0.67–0.72) were high with all techniques. An higher (p ≤ 0.01) percentage of class 1 lesions were found at necropsy compared to all the ultrasonographic techniques. All the ultrasonographic techniques effectively detected lung consolidation deeper than 1 cm. So, ultrasonography seems an effective tool for lung examination in goats with chronic pneumonia. The examination using the linear or the convex probes without shaving the hair could be a promising tool for the on-field diagnosis of pneumonia, although further research on larger sample sizes are necessary to validate these findings. [ABSTRACT FROM AUTHOR]

Reservoirs and their morphological characteristics are expected to alter the continuity of matter, energy, and nutrient transfer, which can modify resource availability, food supply, and fish trophic structure. We studied 29 reservoirs in Southern Brazil to verify the main factors related to the structure of their fish trophic guilds. We tested the hypothesis that environmental and morphological variables influence the organization of fish trophic guilds more than spatial variables (i.e., hydrological distance between the reservoirs). Additionally, we tested which variables linked to environmental, morphological, and spatial characteristics are most associated with the predominance of herbivores, omnivores, detritivores, insectivores, invertivores, and piscivores fishes. To assess the influence of these predictors, we used variance partitioning with distance-based redundancy analysis. Contrary to our assumptions, the structure of fish trophic guilds revealed that the spatial features were the most important predictors. Still, associations between and with the other predictors also revealed significant explanations. Trophic guilds that showed spatial segregation were herbivores and omnivores which can be associated with the evolutionary processes from the locality of each reservoir in distinct ecoregions. Overall, environmental and morphological characteristics like concentration of total nitrogen, age, size, and water retention time are associated with a greater or lesser abundance of herbivores, detritivores, omnivores, and piscivores. Our findings have important implications for the management of reservoirs by helping to guide policies and actions involving fishing stocks. [ABSTRACT FROM AUTHOR]

Geopolymers are amorphous aluminosilicate inorganic polymers synthesized by alkaline activation characterized by a lower carbon footprint, greater durability, and excellent mechanical properties compared to traditional concrete, making them promising building materials for sustainable construction. To develop sustainable lightweight geopolymer-based building materials useful as fire resistant thermal insulation materials, we added 5 and 10 wt% of discarded cork dust, a readily available industrial by-product, to metakaolin before and after the alkaline activation with sodium hydroxide 8 M and sodium silicate solutions. We followed the chemical, microstructural, antibacterial, and physical properties of the resulting composites for up to 90 days in order to monitor their long-term durability. The presence of cork does not interfere with the geopolymerization process and in fact reduces the density of the composites to values around 2.5 g/cm3, especially when added after alkaline activation. The composites resulted in chemically stable matrices (less than 10 ppm of cations release) and filler (no hazardous compounds released) with a bacterial viability of around 80%. This study provides valuable insights into the tailoring of discarded cork-based composites obtained by geopolymerization with a porosity between 32 and 48% and a mechanical resistance to compression from 15 to 5 MPa, respectively, suggesting their potential as durable interior panels with low environmental impact and desirable performance. [ABSTRACT FROM AUTHOR]

Although protected areas (PAs) are designed to safeguard natural ecosystems from anthropic modifications, many PAs worldwide are subjected to numerous human-induced impacts. We evaluated whether the establishment of PAs in the Upper Paraná River floodplain region could reduce anthropic landscape changes and whether there is a difference in protection when using different PA restriction categories. We analyzed the overall landscape dynamics using 30 years of land-use time series data and evaluated the change intensity via a partial land-use intensity analysis. Despite the increasing landscape anthropization, the PAs seemed to relieve the general change process, protecting natural areas mainly from agricultural expansion. Concerning the degree of use restriction, more restricted protection led to less human-induced changes. Finally, accessing PA effectiveness is a multidisciplinary challenge for researchers; however, this knowledge is crucial to avoid misunderstandings or poorly crafted public policies or decisions that may harm the environment. [ABSTRACT FROM AUTHOR]

The introduction of non-native species (NNS) and the resulting biological invasions are conspicuous features of the Anthropocene Epoch. Parallel to these phenomena, some initiatives (political, social and scientific) have sought to value and protect invasive populations, recognizing some benefits that NNS may deliver to people and nature. Given this growing trend of valuing NNS, we considered opportune to address this issue in the context of megadiverse tropical countries. We investigated an emerging trend that has advocated the protection of highly invasive fishes by legal instruments, i.e., the protection of invasive peacock basses (genus Cichla) in Brazil. We recorded 16 bills or laws proposed between 2017 and 2022 that determine fishing restrictions to protect invasive Cichla spp. from overfishing and other impacts, in order to favor population recruitment, growth, colonization and spread. Specifically, they establish restrictions on fishing, capture, transport, trade, and processing, including quotas, compulsory catch and release, length limits, use of gears, and temporal interdictions. They also determine the naturalization of peacock basses in some main basins of South America, which include different watersheds and ecoregions, with risk of intercountry invasions. This particular case is instructive to unveil the risks of positions that emphasize positive contributions of NNS to society and nature, as these misguided conservation actions favor invasive organisms with high potential to cause environmental degradation, biodiversity losses, and social conflicts. These positions find fertile ground in some contexts, especially in tropical developing countries, where economic constraints, poor access to information, opportunism, and bad political behavior have been the norm. [ABSTRACT FROM AUTHOR]

To understand how Neotropical freshwater fishes (NFF) benefit society, we conducted a broad literature survey to (i) map and list the ecosystem services (ES) generated by these organisms, and (ii) investigate how human activities have affected the ecosystem service chain. We found sound evidence that NFF contribute directly and indirectly to the generation of several provisioning, regulating, supporting, and cultural services. Provisioning services have been widely recognized, especially those related to fisheries, but this class also included ornamental fish, genetic pools, medicines, aquaculture, and bioindicators. Other services remain less understood and largely ignored by society. Regulating services included seed dispersal, decomposition, and top-down control, while supporting services included nutrient cycling, habitat quality, and ecosystem engineering. Cultural services associated with NFF included recreational fishing, tourism, fishkeeping, education, production of scientific knowledge, in addition to values linked to traditional communities, such as local knowledge, cosmology, and existential foundations. Human activities have negatively impacted the generation of ES, especially those related to fishing and food provisioning. This review indicates that Neotropical fishes benefit society in multiple ways, but it is imperative to improve our understanding about those benefits, and to increase conservation efforts directed to this important component of global biodiversity. [ABSTRACT FROM AUTHOR]

Bacterial infection of the central nervous system (CNS) in cattle requires prompt and adequate antimicrobial treatment. The current gold standard for antemortem etiological diagnosis is cerebrospinal fluid (CSF) culture, which often yields false negative results. CSF has long been considered a sterile district in healthy patients, but this notion has been recently challenged. For this pilot study, we used 16S rRNA gene sequencing to investigate the microbial composition of CSF of cattle presenting with CNS disorders and to compare it between subjects with CNS infections and with CNS disorders of other nature. The study sample was 10 animals: 4 presenting with CNS infectious-inflammatory diseases and 6 with other CNS disorders, based on definitive diagnosis. Since the initial round of a standard 16S rRNA PCR did not yield sufficient genetic material for sequencing in any of the samples, the protocol was modified to increase its sensitivity. Bacterial genetic material was identified in 6 animals and 2 groups were formed: an infectious inflammatory (n = 3) and a noninfectious inflammatory group (n = 3). The most frequently expressed bacterial families were Pseudomonadaceae (44.61%), Moraxellaceae (19.54%), Mycobacteriaceae (11.80%); the genera were Pseudomonas (45.42%), Acinetobacter (19.91%), Mycobacterium (12.01%). There were no detectable differences in the CSF microbial composition of the samples from the two groups. Sequencing of bacterial DNA present in the CSF was possible only after increasing PCR sensitivity. The results of 16S rRNA sequencing showed the presence of a microbial community in the CSF in cattle with neurological disorders. Further studies, in which CSF samples from healthy animals and samples from the environment are included as controls, are needed. [ABSTRACT FROM AUTHOR]

In this study, we assessed the invasion process of non-native fish species in the upper Paraná River floodplain using survey data from 1986 to 2018. We aimed to answer three questions: (1) whether the abundance of non-native species differed among lakes and rivers; (2) whether the probability of occurrence of non-native species differed among lakes and rivers over time, and (3) whether the probabilities of occurrence of non-native species are explained by their functional traits, phylogenetic relationships, or the area of native range. An analysis of covariance was performed to determine the differences in species abundance between habitats. The probability of occurrence for each non-native species was determined through logistic regression. To identify the factors that explain the probability of occurrence, the probability of occurrence at the first and last year of the sampled period was modelled as a function of the native range of the species and the axes from the ordinations of functional traits and phylogenetic relationships. Species abundance was highest in lakes, while the probability of occurrence of species was highest in rivers. Range size, functional traits of life history, and habitat use dimensions, positively affected the probability of occurrence of non-native species. The most important functional traits were offspring investment, egg size and fertilization type, defense, and shape factor. [ABSTRACT FROM AUTHOR]

Extreme climate events and the damming of natural rivers can intensify the effects of droughts and floods, which can consequently affect aquatic biota. We investigated whether a prolonged drought increased the similarity of aquatic metacommunities over time when compared to a period with extreme flood events in 10 floodplain lakes. We expected to find (i) lower temporal environmental variability and lower β diversity among months during the prolonged drought period, and (ii) a more pronounced decrease in β diversity for aquatic organisms with active dispersal (fish) than for small organisms with passive dispersal (phytoplankton and zooplankton) during the prolonged drought period. We estimated the β diversity among months using the Sørensen and Bray–Curtis dissimilarities and their components separately for each lake and each period. We used paired t tests to compare the periods. Although the prolonged drought reduced environmental variability, the homogenization of biota was dependent on the considered β diversity component. In the face of climate change and a higher frequency of severe droughts, biotic variability can decrease over time, thereby changing the dynamics of floodplain ecosystems. We emphasize the importance of natural flood events for maintaining environmental variability and ecosystem functioning in floodplains. [ABSTRACT FROM AUTHOR]

Habitat complexity can substantially alter trophic relationships, such as competitive and predatory interactions, between fish species. This study aimed to evaluate how trophic interactions between congeneric fish species (Serrapinnus calliurus, S. heterodon and S. notomelas) are affected by habitat complexity provided by macrophytes. The following predictions were tested: (1) the composition of the diets of congeneric fish species differs between high- and low-complexity habitats and between habitats of the same category; (2) species show higher trophic niche breadth in sites with greater habitat complexity; and (3) trophic niche overlap between congeneric species pairs is low in macrophyte stands because of greater food availability. Sampling was conducted between November 2011 and July 2012 in five floodplain lakes of the Baía River, a tributary of the upper Paraná River. The degree of habitat complexity was categorised as high (with macrophytes) or low (without macrophytes). The stomach contents of the three species sampled from sites of high- or low-complexity habitat were analysed. Diet variation depended on habitat complexity. The median trophic niche breadth of the three congeneric species was low, but their diets showed higher variability in sites of high-complexity habitat. Significant differences in trophic niche overlap were observed in two species pairs when comparing sites of high- and low-complexity habitat. Habitat complexity directly affected trophic interactions between the fish species, which may favour their coexistence through trophic niche segregation. Our study emphasises the importance of habitat complexity in mediating trophic interactions between congeneric species and clarifies the coexistence of ecologically similar fish species. [ABSTRACT FROM AUTHOR]

The sol–gel process was used to synthesize four organic/inorganic hybrid materials by entrapping different amounts of quercetin (Q), namely 5, 10, 15 and 20 mass%, in a silica (S) matrix. A detailed characterization focused on revealing the nature of the bonds between the inorganic and organic components was performed by Fourier transform infrared (FTIR) spectroscopy. Silica/quercetin (SQ) hybrid materials showed an increase in the mass loss percentages of the first decomposition step with increasing the amount of Q, thus suggesting the incorporation of Q in the hybrid materials and a stabilization of the structure by hydrogen bonds. The morphology of the SQ hybrids investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS) confirmed a regular size distribution of the particles and a homogeneous distribution of quercetin in the silica matrix in the suitable expected ratio. Furthermore, the SEM images confirmed the absence of contaminants during the sol–gel synthesis. Finally, the antibacterial properties of the SQ hybrid materials were tested using four (two Gram-positive and two Gram-negative) bacteria strains. The results demonstrated that they can be proposed as valuable antibacterial agents against Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria and Staphylococcus aureus and Enterococcus faecalis as Gram-positive for amounts above 50 mg. [ABSTRACT FROM AUTHOR]

In freshwater ecosystems, flood pulses, the degree of connectivity between environments, and the vegetation mosaic are among the main variables affecting environmental structure at the landscape scale. At a finer scale, local limnological conditions seem to be more important for structuring river fish assemblages. However, rather than exerting isolated effects, these limnological characteristics can have combined impacts on the environment. We evaluated the main drivers of the spatial structuring of fish trophic guilds in the littoral zone of lakes in the Upper Paraná River floodplain (UPRF) and determined the relative importance of limnological conditions, spatial distance, and riparian vegetation. We sampled fish and limnological variables in June, September, and December of 2011, and classified the fish species into trophic guilds. We used variation partitioning analysis to assess the influence of the three sets of predictors and distance-based redundancy analysis to visualize the position of samples, as described by the composition of trophic guilds in multivariate space. The distribution of trophic guilds was mainly influenced by limnological variables, i.e., conductivity, chlorophyll a, and pH, in periods of low water. Spatial and riparian vegetation predictors, despite being low, also influenced the distribution because limnological variables and riparian vegetation of the UPRF have a well-defined spatial structure due to differences between rivers. The lakes with Class III riparian vegetation (dominated by tree species) supported most of the trophic guilds, including insectivores. This indicates that allochthonous materials, even when they occur in smaller proportions, contribute to the structuring of fish communities in periods of low water. [ABSTRACT FROM AUTHOR]

Ichthyoplankton drift is threatened by hydropower dams elsewhere. Here we evaluated whether eggs and larvae of fish can perform downstream movements along a large reservoir in a white-water river on the Amazon. Samplings were performed in the reservoir and downstream from Santo Antônio dam. Generalized linear models with negative binomial distribution and logarithmic link function were fitted to model the ichthyoplankton drift throughout the reservoir. Six different models were fitted having the abundances of ichthyoplankton as the response variable. The linear predictor differed as to the inclusion of the predictor variables larval development stage, sampling sites and dam distance (linear and quadratic effect). All ichthyoplankton and the most representative taxonomic orders were analyzed. The results indicate that fish reproductive activity occurred both upstream Jirau Dam and within the Santo Antônio Reservoir. Some part of the ichthyoplankton transposed the Santo Antônio Dam, reaching downstream. However, all of the taxonomic orders presented both reproductive activity and disappearance of at least some of their larval development stages along the reservoir. The most critical section was in the last 10 km of the reservoir, possibly as result of the drifting characteristics or of mortality rates. [ABSTRACT FROM AUTHOR]

The Tocantins-Araguaia Basin is one of the largest river systems in South America, located entirely within Brazilian territory. In the last decades, capital-concentrating activities such as agribusiness, mining, and hydropower promoted extensive changes in land cover, hydrology, and environmental conditions. These changes are jeopardizing the basin's biodiversity and ecosystem services. Threats are escalating as poor environmental policies continue to be formulated, such as environmentally unsustainable hydropower plants, large-scale agriculture for commodity production, and aquaculture with non-native fish. If the current model persists, it will deepen the environmental crisis in the basin, compromising broad conservation goals and social development in the long term. Better policies will require thought and planning to minimize growing threats and ensure the basin's sustainability for future generations. [ABSTRACT FROM AUTHOR]

Modern biological invasions represent a major facet of the Anthropocene, yet the invasive potential of species remains poorly understood. In this context, this study compared ecological traits of native and non-native populations of Cichla kelberi, a powerful invader, to investigate the hypothesis that this fish exhibits phenotypic and behavioral variations, which may confer adaptability to different conditions. Data on population structure, trophic ecology, and reproduction were collected from populations in different Neotropical impoundments. We found differences in population structure, with larger mean sizes and a lower proportion of juveniles in the native population. All populations exhibited piscivore behavior, but a higher incidence of empty stomachs and a less diverse diet characterized some non-native populations, with the consumption of non-fish resources and cannibalism. Non-native populations also showed prolonged reproduction and early maturity. In general, differences were not restricted to the contrast native vs. non-native, as introduced populations showed considerable divergence among themselves. Results confirmed the existence of phenotypic and behavioral variation in C. kelberi, which must affect its invasive potential by conferring adaptability to novel conditions in specific localities and contexts. These aspects make C. kelberi an almost certain invader of artificial impoundments located in tropical ecosystems of the world. [ABSTRACT FROM AUTHOR]

Gas chromatography with mass spectrometry detection (GC-MS) coupled with headspace-solid-phase microextraction (HS-SPME) was used to analyse the aroma profile of genuine saffron (Crocus sativus L.) and samples of this spice artificially adulterated with Calendula officinalis L. petals (calendula), Carthamus tinctorius L. petals (safflower) and Curcuma longa L. powdered rhizomes (turmeric). Preliminary analyses of genuine saffron and pure contaminants were performed to select the kind of SPME sorbent. Moreover, an experimental design combined with response surface methodology was applied to optimise the sample temperature and the fibre exposure time with the aim of enhancing the detection of the above adulterants in counterfeited saffron samples. The GC-MS chromatograms collected under the optimised conditions were finally handled by unsupervised and supervised multivariate statistical methods to differentiate the genuine saffron samples produced in three different Italian regions from artificially adulterated samples at 2–5% w/w contamination levels. Thirty genuine and 30 counterfeited (10 for each kind of adulterant) saffron samples were analysed. Principal component analysis was applied to assist the choice of the GC/MS data pre-treatment and classification of genuine and adulterated saffron samples was attempted by partial least square-discriminant analysis (PLS-DA). Predictive performance of PLS-DA models calibrated with 42 samples was finally tested on 18 saffron samples (9 genuine and 9 adulterated). All the external saffron samples were correctly classified regardless of the kind of contaminant, while in calibration, only a saffron sample contaminated with safflower was erroneously assigned to the group of genuine ones. Class modelling of genuine saffron performed by SIMCA (Soft Independent Model Class Analogy) exhibited a good sensitivity and 100% specificity for external adulterated samples. [ABSTRACT FROM AUTHOR]

Twenty-nine different Iranian and Italian saffron samples have been characterized using high-performance liquid chromatography (HPLC) equipped with UV–Vis detection as well as ultraviolet–visible (UV–Vis) spectroscopy methods by preparing aqueous extracts according to the ISO 3632 standard. UV–Vis spectral data in the wavelength range of 200–600 nm and the intensities of the chromatographic peaks attributed to picrocrocin, safranal and crocetin esters were considered as variables in principal component analysis (PCA) and linear discriminant analysis (LDA) methods to classify Iranian and Italian saffron samples based on their geographical origin. The geographical classification results based on HPLC data indicated safranal, cis-crocetin (β-d-gentiobiosyl)(β-d-glucosyl) ester (C3Gg), trans-crocetin (β-d-neapolitanosyl)(β-d-glucosyl) ester (T4ng), and trans-crocetin (β-d-gentiobiosyl)(β-d-glucosyl) ester (T3Gg) as the most discriminant. The best classification performance was achieved by the UV–Vis spectra where the most discriminant regions can be associated with both cis- and trans-crocins (326–327 and 260–264 nm), safranal (310 nm), picrocrocin (240–250 nm), and kaempferol derivatives (265 and 340–350 nm). [ABSTRACT FROM AUTHOR]

PDO (protected designation of origin) Zafferano dell'Aquila (AQ), Iranian (IR), and commercial (CS) saffron samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The ICP-MS data of 30 elements were handled by unsupervised (principal component analysis (PCA)) and supervised (linear discriminant analysis (LDA)) multivariate statistical methods to identify a subset of discriminant variables useful for geographical classification. Moreover, class modeling of AQ saffron was performed by both UNEQ (unequal disperses classes) and SIMCA (soft independent modeling of class analogy) methods. A good differentiation of the AQ, IR, and CS samples was obtained by the LDA based on four selected elements: Sr, Ca, Mo, and Fe. A UNEQ class model for the PDO AQ saffron based on the above four elements provided 100% sensitivity (all authentic AQ saffron were accepted) and 100% specificity (all IR and CS were rejected), while slightly worse results were obtained using the SIMCA (89% sensitivity and 96% specificity). [ABSTRACT FROM AUTHOR]

The topic of biological invasion has adopted the concepts of neophobia and dietary conservatism to explain why some species are reluctant to include nonnative species in their diets, with prey naïveté predicting that prey would not be able to recognize novel predators in the environment. This is particularly true for fish, for which studies are rare, mainly in natural environments. Here, the existence of feeding selectivity in terms of prey origin was investigated in nature by quantifying the contribution of nonnative prey to the diets of native and nonnative predators. Three distinct rivers in the upper Paraná River basin (Brazil) and 13 piscivores were used to test the hypothesis. Out of the 650 possible trait combinations, only prey body shape (sagittiform) and predator relative body height were found to be correlated. Even though native and nonnative prey presented similar functional traits, very strong selectivity by prey origin was observed, with native predators positively selecting native prey. Native predators possibly do not recognize nonnative prey or lack the necessary ability to prey upon nonnative prey. Such findings show that, for several predators, prey origin does matter. There are many implications of "predator naïveté", as an increasing number of nonnative species are being introduced worldwide, with advances in such area enabling a better understanding of several limitations in biological invasions. Perhaps looking through the predator's eyes might bring some novel perspective and help to understand some as yet unexplainable paradigms in biological invasions. [ABSTRACT FROM AUTHOR]

The colonization of novel reservoirs tends to support opportunistic species that undergo mass proliferation after the reservoir is formed. It is common that in this process, a species will change its diet based on resource availability. This is the case in the Salto Caxias reservoir, Iguaçu River, where five Astyanax species presented changes in their diets after damming. The present study aimed to evaluate possible changes in the feeding activity and condition factor of five sympatric species of Astyanax in the Salto Caxias reservoir in different areas impacted by damming. Sampling was carried out before and after damming the Salto Caxias reservoir. The fish feeding activity and nutritional status were inferred by the mean stomach repletion index and the mean condition factor, respectively. Most of the studied species showed a general decrease in feeding activity and condition factor. Both studied regions, the upstream region and the dam region, presented changes in the analyzed factors. These observations suggest that regardless of diet changes, nutritional status is negatively impacted in altered environments. The nutritional deficit occurs (i) if the diet is altered due to adaptive limitations on the use of the available resources and (ii) if the diet remains unaltered due to the scarcity of the preferred feeding resource. Such decreases might lead to reductions in the population size due to limitations on growth and reproduction until the environment feeding resources can sustain those populations. [ABSTRACT FROM AUTHOR]

Migratory fishes are one of the groups most threatened by the interruption of river connectivity caused by reservoirs and dams. The downstream displacement of eggs and larvae of these species implies overcoming the barrier presented by the reservoir and passage through the hydraulic structures of the dam. Although a low water renewal time attenuates the drift constraints on eggs and larvae in the reservoir, these organisms still require safe passage through these structures, which represents an additional challenge that demands methodological tools for impact assessment and management evaluation to subsidise operational decision making. This paper presents a protocol to help fill current gaps in knowledge of the impact of hydropower dams on the survival of fish larvae travelling through the hydraulic components of dams. A sampling and analysis design capable of in situ assessment of the effects of passage by the larvae through dams is presented and discussed along with potential alternatives to support hydraulic structure management and mortality reduction as well as inferences on the effectiveness of fish translocation strategies. The proposed approach is a new possibility for the in situ assessment of downstream ichthyoplankton passage through dams. The proposed sampling design is relatively simple, easily executed and affordable compared to those demanding more sophisticated technologies or that combine field and lab studies to associate fish injuries and mortality with the downstream passage through dams operating under different regimes. Its rapid diffusion is important given the accelerated expansion of the hydroelectric sector, especially in the main tropical basins. [ABSTRACT FROM AUTHOR]

Gas cromatography with mass spectrometry detection coupled to headspace solid-phase microextraction (SPME) was used to analyse the aroma profile of saffron (Crocus sativus L.). The influence of the saffron amount and form (intact stigmas vs. powder) on the intensity of the chromatograms was preliminarily evaluated. Moreover, the mutual effects of the sample temperature and exposition time of a polydimethylsiloxane SPME fiber was investigated by response surface methodology. Saffron samples produced in L’Aquila (Italy), Iran and Morocco, and commercial spices were analysed under application of the optimised SPME conditions and geographical classification was attempted by linear discriminant analysis applied to the relative peak areas of all the detected volatiles. The spices produced in the different geographical areas and the commercial products were discriminated with good accuracy, 91% of external samples being correctly classified using leave-one-out cross-validation. An acceptable differentiation (73% of correct predictions) was obtained by considering only the major aroma components. [ABSTRACT FROM AUTHOR]

Dams have altered the physiography and ecology of large rivers, causing severe environmental changes at a global scale. Assuming that series of reservoirs induce physical, chemical, and biological longitudinal changes in rivers, we tested the hypotheses that (i) the structure of biological communities in reservoir cascades is not only affected by changes in water quality, but also by cumulative hydrological alteration and impacts on river connectivity; and (ii) fish are more affected by cumulative effects of reservoirs when compared to other aquatic assemblages. Samplings of three assemblages (phytoplankton, benthic macroinvertebrates, and fish) were conducted in the reservoir cascade of São Francisco River, Brazil. We estimated the relative role of environmental and spatial predictors through variation partitioning analyses. Environmental variables, cumulative reservoir volume, longitudinal position, and distances from nearest reservoirs were used as explanatory variables. Environmental variables were the most important for the phytoplankton community. No significant effects of the predictors used were found for benthic macroinvertebrates, whereas spatial variables and cumulative reservoir volume were the most important predictors for fish. Therefore, our results provide evidence of impacts along reservoir cascades, and suggest that their effects mainly influence fish assemblages. [ABSTRACT FROM AUTHOR]

This study assessed the feeding strategies of nine fish species in their native (Cuiabá River) and in an invaded basin (upper Paraná River) to identify trophic variables that may explain the success of these species in the new basin, over 30 years. The following predictions were analyzed: (i) species that display omnivorous or piscivorous diets in the native basin are favored in the invasion process over the long term, and (ii) specialist feeders are favored in the invasion process provided that their food items are highly available in the invaded area. These predictions were supported by the data; the species that were successful invaders had high trophic plasticity (omnivores), consumed a wide variety of food items from specific trophic guilds (piscivores), or if a species had a specialized diet, the resources demanded are abundant (detritivores). Thus, in a long-term perspective, the food resources used by these species are rarely limiting in aquatic ecosystems, and these feeding characteristics should be one of the key factors determining the colonization success of fishes. Understanding the factors that determine the success of invasive species in new areas is critical for developing management policies aimed at minimizing the impacts of biological invasions. [ABSTRACT FROM AUTHOR]

In this paper, we use a quantitative structure-retention relationship (QSRR) method to predict the retention times of polychlorinated biphenyls (PCBs) in comprehensive two-dimensional gas chromatography (GC×GC). We analyse the GC×GC retention data taken from the literature by comparing predictive capability of different regression methods. The various models are generated using 70 out of 209 PCB congeners in the calibration stage, while their predictive performance is evaluated on the remaining 139 compounds. The two-dimensional chromatogram is initially estimated by separately modelling retention times of PCBs in the first and in the second column ( t and t, respectively). In particular, multilinear regression (MLR) combined with genetic algorithm (GA) variable selection is performed to extract two small subsets of predictors for t and t from a large set of theoretical molecular descriptors provided by the popular software Dragon, which after removal of highly correlated or almost constant variables consists of 237 structure-related quantities. Based on GA-MLR analysis, a four-dimensional and a five-dimensional relationship modelling t and t, respectively, are identified. Single-response partial least square (PLS-1) regression is alternatively applied to independently model t and t without the need for preliminary GA variable selection. Further, we explore the possibility of predicting the two-dimensional chromatogram of PCBs in a single calibration procedure by using a two-response PLS (PLS-2) model or a feed-forward artificial neural network (ANN) with two output neurons. In the first case, regression is carried out on the full set of 237 descriptors, while the variables previously selected by GA-MLR are initially considered as ANN inputs and subjected to a sensitivity analysis to remove the redundant ones. Results show PLS-1 regression exhibits a noticeably better descriptive and predictive performance than the other investigated approaches. The observed values of determination coefficients for t and t in calibration (0.9999 and 0.9993, respectively) and prediction (0.9987 and 0.9793, respectively) provided by PLS-1 demonstrate that GC×GC behaviour of PCBs is properly modelled. In particular, the predicted two-dimensional GC×GC chromatogram of 139 PCBs not involved in the calibration stage closely resembles the experimental one. Based on the above lines of evidence, the proposed approach ensures accurate simulation of the whole GC×GC chromatogram of PCBs using experimental determination of only 1/3 retention data of representative congeners. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

We performed an experimental manipulation of trahira Hoplias aff. malabaricus in a series of isolated lakes of the upper Paraná River floodplain to evaluate its short-term impact on the structure of fish assemblages. The effects of trahira density (treatment groups: addition, removal, and reference) in two habitat categories (open and macrophyte-covered areas) on attributes of the fish assemblage structure were evaluated (using rm-ANOVA) over 120 days. Reductions in species richness were recorded in all assemblages and were more pronounced at the end of the experiment within macrophyte-covered areas of the lakes where H. aff. malabaricus was removed. In these lakes, the number of fish was also significantly smaller and evenness was significantly higher than in those in which trahira were added or maintained at natural densities. The increase of the relative abundance of all size classes over the first 60 days on the assemblages where trahira was present, and the decrease of the small-sized fish where trahira was absent contributed to the lack of pronounced alterations in total biomass. The absence of the predator from its preferred habitat was found to negatively affect the less abundant species, which seemed to be highly sensitive to the effects of interspecific competition among prey species. In addition to the well-known effects of hydrological seasonality, the role played by native predators might be important in determining the persistence of local species in the fish assemblages of Neotropical floodplains. [ABSTRACT FROM AUTHOR]

The present study evaluated the hypothesis that after flooding events, non-random patterns of species co-occurrence (segregation) are progressively intensified in fish assemblages inhabiting seasonally isolated lagoons. We sampled lagoons in the upper Paraná River floodplain between 1992 and 1993, and classified them into five hydrological phases, according to their surface connectivity. During the period of isolation (9 months), lagoons depth decreased progressively, but desiccation was reversed after 4 months (possibly due to groundwater infiltration and rainfall). A significant co-occurrence pattern (segregation) occurred in the last phase, supporting our initial hypothesis. However, richness, abundance and composition were significantly correlated with habitat depth, indicating that assemblage structure and organization is closely associated with dynamics of habitat retraction/expansion during isolation. Although environmental conditions of lagoons (absence of prolonged desiccation) prevented an adequate test of our hypothesis, our data suggests that, in addition to the importance of surface floods, the hydrological cycle as a whole has a crucial role shaping the organization of fish assemblages in floodplain lagoons seasonally isolated. [ABSTRACT FROM AUTHOR]

Examines the diversity of fishes in Água Nanci stream in Brazil. Variation in specie density; Habitat preferences of the fishes; Biotic interaction of the fish fauna.

Over the years, several materials have been used for restoration purposes, with different types of dyes and colour hues. Recently, some researchers have proposed geopolymers (GPs) or amorphous aluminosilicate polymers for these purposes. In this work, an alcohol-based grape marc extract (GME, obtained via dark maceration assisted with ultrasound) was used as a natural dyeing agent for metakaolin-based GPs. The geopolymerisation occurrence was assessed by Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction analysis, while the colour of the resulting material was determined through the colorimetric analysis in the L*a*b* colour space. Additionally, the thermal stability of GME and GPs was investigated by thermogravimetry coupled with FT-IR spectroscopy. The microstructure, the reticulation stability, and the antimicrobial activity of GPs were examined through the scanning electron microscopy, the pH and ionic conductivity measurements, integrity, and mass loss tests. Overall, a coloured geopolymer with suitable thermal, antimicrobial, and mechanical properties was obtained, justifying its potential use in restoration or, more generally, in the construction field.Graphical abstract: Over the years, several materials have been used for restoration purposes, with different types of dyes and colour hues. Recently, some researchers have proposed geopolymers (GPs) or amorphous aluminosilicate polymers for these purposes. In this work, an alcohol-based grape marc extract (GME, obtained via dark maceration assisted with ultrasound) was used as a natural dyeing agent for metakaolin-based GPs. The geopolymerisation occurrence was assessed by Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction analysis, while the colour of the resulting material was determined through the colorimetric analysis in the L*a*b* colour space. Additionally, the thermal stability of GME and GPs was investigated by thermogravimetry coupled with FT-IR spectroscopy. The microstructure, the reticulation stability, and the antimicrobial activity of GPs were examined through the scanning electron microscopy, the pH and ionic conductivity measurements, integrity, and mass loss tests. Overall, a coloured geopolymer with suitable thermal, antimicrobial, and mechanical properties was obtained, justifying its potential use in restoration or, more generally, in the construction field. [ABSTRACT FROM AUTHOR]

Impoundments alter connectivity, sediment transport and water discharge in rivers and floodplains, affecting recruitment, habitat and resource availability for fish including benthic invertivorous fish, which represent an important link between primary producers and higher trophic levels in tropical aquatic ecosystems. We investigated long-term changes to water regime, water quality, and invertivorous fish assemblages pre and post impoundment in three rivers downstream of Porto Primavera Reservoir in south Brazil: Paraná, Baía and Ivinhema rivers. Impacts were distinct in the Paraná River, which is fully obstructed by the dam, less evident in the Baía River which is partially obstructed by the dam, but absent in the unimpounded Ivinhema River. Changes in water regime were reflected mainly as changes in water-level fluctuation with little effect on timing. Water transparency increased in the Paraná River post impoundment but did not change in the Baía and Ivinhema rivers. Changes in fish assemblages included a decrease in benthic invertivorous fish in the Paraná River and a shift in invertivorous fish assemblage structure in the Baía and Paraná rivers but not in the unimpounded Ivinhema River. Changes in water regime and water transparency, caused by impoundment, directly or indirectly impacted invertivorous fish assemblages. Alterations of fish assemblages following environmental changes have consequences over the entire ecosystem, including a potential decrease in the diversity of mechanisms for energy flow. We suggest that keeping existing unimpounded tributaries free of dams, engineering artificial floods, and intensive management of fish habitat within the floodplain may preserve native fish assemblages and help maintain functionality and ecosystem services in highly impounded rivers. [ABSTRACT FROM AUTHOR]

This study evaluated the impact of Cichla spp. on the functional diversity of small fishes in floodplain lakes from 2002 to 2019, Brazil. Using multivariate regression, we analyzed how functional richness, evenness, divergence, and dispersion indices respond to fluctuations in Cichla spp. abundance and seasonal water levels. Preliminary cross-correlations helped clarify the temporal influence of Cichla spp. on these indices. Results revealed a significant correlation between water levels and all functional indices. After controlling for water level variations, increases in Cichla spp. abundance significantly and negatively affected functional richness and dispersion. Specifically, higher Cichla spp. abundance correlated with reduced functional richness and dispersion after lags of 9 and 21 months, respectively. Additionally, at a 9-month lag, functional divergence was negatively associated with Cichla spp. abundance, whereas an 18-month lag showed a positive influence of functional richness on Cichla spp. abundance, suggesting a cyclical interaction. The study indicates that high Cichla spp. abundance can destabilize crucial community segments, particularly smaller fish species, through a feedback loop of impact. Future studies should explore the factors influencing Cichla spp. abundance, focusing on environmental dynamics. Understanding the interactions between these elements will help clarifying Cichla spp. population trends. Interventions are necessary to mitigate propagule pressure and manage Cichla spp. populations effectively within these ecosystems. [ABSTRACT FROM AUTHOR]