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Fish mercury concentrations result in fish consumption advisories. However, selenium : mercury molar ratios >1 are protective to wildlife and humans. Therefore, we sampled total selenium (TSe) and total mercury (THg) concentrations and molar ratios in sport fish from 50 Idaho (ID) lakes >20 ha and 67 northeastern USA (NE) lakes >1 ha. Sample lakes were selected at random, to obtain unbiased estimates of mean fish tissue levels, with known confidence limits, for target populations of 95 ID lakes >20 ha in surface area and 12,557 NE lakes >1 ha. Bass and salmonids presented the greatest potential mercury toxicity risk to consumers based on their higher mercury content, desirability as game fish, and widespread distributions. Fish tissue THg exceeded safe consumption criteria in an estimated 20–80% of the lakes in the two regions and TSe exceeded safe consumption thresholds in an estimated 0–20% of the lakes in the two regions. However, the Se : Hg molar ratio was >1 in an estimated 90–97% of fish tested from NE and ID lakes. Therefore, we concluded that Se levels in these systems are usually sufficient to limit disruption of selenoprotein activities by Hg, and that fish consumption advisories based on Hg alone are unnecessarily restrictive. [ABSTRACT FROM AUTHOR]

Surface water drying challenges the persistence of lotic biological assemblages in non‐perennial streams and rivers. However, the effects of natural hydrological disturbances on an assemblage depend on individual species characteristics. In this study, we investigated the structure and association of fish and macroinvertebrate assemblages during two phases in non‐perennial streams (flowing vs. disconnected pools). We sampled fish and macroinvertebrate assemblages in five non‐perennial stream reaches located in the Caatinga (Brazilian semi‐arid region). Fish species were resistant to hydrological dynamics in the streams. On the other hand, some macroinvertebrate taxa from the flowing phase disappeared, and new taxa colonized the disconnected pools. The absence of lotic insects following flow cessation and the colonization of disconnected pools by lentic taxa facilitated macroinvertebrate assemblages persistence in these dynamic streams. Our study showed that fish and macroinvertebrate assemblages respond differently to the same natural flow cessation, which leads us to predict that flow changes will yield different assemblages, depending on the taxa. Thus, it is crucial to consider multi‐assemblage responses to effectively manage and conserve non‐perennial stream ecosystems in a tropical semi‐arid region. We investigated the structure and association of fish and macroinvertebrate assemblages with two aquatic phases in non‐perennial streams (flowing vs. disconnected pools). Our study showed that fish and macroinvertebrate assemblages respond differently to the same natural flow cessation, which leads us to predict that flow changes will yield completely different assemblages, depending on the taxa. [ABSTRACT FROM AUTHOR]

Knowledge of seabird distributions plays a key role in seabird conservation and sustainable marine management, underpinning efforts to designate protected areas or assess the impact of human developments. Technological advances in animal tracking devices increasingly allow researchers to acquire information on the movement of birds from specific colonies. Nevertheless, most seabird colonies have not been subject to such tracking and another means must be found to assess their likely foraging distribution. Consequently, foraging range data collated and summarized across other tracking studies has often been used to estimate species‐level foraging distances for use within applied settings. However, generic species‐specific foraging ranges must be used with caution because of the amount of variation in seabird foraging behaviour at both the individual and colony levels. Specifically, although current reviews of seabird foraging ranges provide summary estimates of maximum foraging range, they typically do not assess the extent of among‐colony or among‐individual variation around such estimates. To address this, we conducted a variance component analysis of the maximum distance reached from the breeding colony per foraging trip (foraging range) using multi‐colony tracking datasets to estimate the degree of between‐individual, between‐year and between‐colony variation in foraging range in four UK breeding seabirds (Black‐legged Kittiwake Rissa tridactyla, Common Guillemot Uria aalge, Razorbill Alca torda and European Shag Gulosus aristotelis). We also provide updated estimates of typical foraging ranges for each species and quantify the influence of breeding stage and colony size. Overall, between‐colony variation was typically the largest variance component, explaining 20–30% of the observed variation in foraging range across the four species. Individual‐level variation was also relatively large among Shag. In Kittiwake, Guillemot and Shag, but not Razorbill, average foraging ranges were positively associated with colony size. In addition, Kittiwake and Razorbill travelled further during incubation than during chick‐rearing. More generally, our estimates of mean foraging ranges for each species were subject to a high degree of uncertainty, which should be incorporated into impact assessments carried out using such data. [ABSTRACT FROM AUTHOR]

Background: Vaso‐occlusive crises (VOCs) cause debilitating pain and are a common cause of emergency department (ED) visits, for people with sickle cell disease (SCD). Strategies for achieving optimal pain control vary widely despite evidence‐based guidelines. We tested existing guidelines and hypothesized that a patient‐specific pain protocol (PSP) written by their SCD provider may be more effective than weight‐based (WB) dosing of parenteral opiate medication, in relieving pain. Methods: This study was a prospective, randomized controlled trial comparing a PSP versus WB protocol for patients presenting with VOCs to six EDs. Patients were randomized to a PSP or WB protocol prior to an ED visit. The SCD provider wrote their protocol and placed it in the electronic health record for future ED visits with VOC exclusion criteria that included preexisting PSP excluding parenteral opioid analgesia or outpatient use of buprenorphine or methadone or highly suspected for COVID‐19. Pain intensity scores, side effects, and safety were obtained every 30 min for up to 6 h post–ED bed placement. The primary outcome was change in pain intensity score from placement in an ED space to disposition or 6 h. Results: A total of 328 subjects were randomized; 104 participants enrolled (ED visit, target n = 230) with complete data for 96 visits. The study was unable to reach the target sample size and stopped early due to the impact of COVID‐19. We found no significant differences between groups in the primary outcome; patients randomized to a PSP had a shorter ED length of stay (p = 0.008), and the prevalence of side effects was low in both groups. Subjects in both groups experienced both a clinically meaningful and a statistically significant decrease in pain (27 mm on a 0‐ to 100‐mm scale). Conclusions: We found a shorter ED length of stay for patients assigned to a PSP. Patients in both groups experienced good pain relief without significant side effects. [ABSTRACT FROM AUTHOR]

The article discusses the U.S. Supreme Court's decision in Sackett vs. U.S. Environmental Protection Agency, which narrows the definition of "waters of the United States" (WOTUS) under the Clean Water Act. The court ruled that wetlands must have a continuous surface connection to a larger water body to be protected under the act, disregarding the goals and objectives of the law. This decision leaves the responsibility of protecting wetlands and streams to states that may lack the resources and political will to do so effectively. The article highlights the importance of wetlands and nonpermanent water bodies for ecosystem services and biodiversity, and calls for continued advocacy and education on the importance of safeguarding these resources. [Extracted from the article]

S. Mažeika Patricio Sulliván, a respected scientist and professor, passed away on May 31, 2024. He was the Director of the Baruch Institute of Coastal Ecology and Forest Science and a Professor at Clemson University. Throughout his career, Sulliván focused on community and trophic ecology, water quality, and land-water linkages in various ecosystems. He was also a leader in promoting diversity, equity, and inclusion in the aquatic sciences. Sulliván's work had a significant impact on shaping the Clean Water Act's definition of Waters of the U.S. (WOTUS), and he was a dedicated advocate for wetlands, headwaters, and estuaries. He was known for his commitment to inclusivity and his efforts to make aquatic science more welcoming for all. Sulliván is survived by his wife and four children. [Extracted from the article]

Human land‐use change is a major threat to natural ecosystems worldwide. Nonetheless, the effects of human land‐uses on the structure of plant and animal assemblages and their functional characteristics need to be better understood. Furthermore, the pathways by which human land uses affect ecosystem functions, such as biomass production, still need to be clarified.We compiled a unique dataset of fish, arthropod and macrophyte assemblages from 61 stream ecosystems in two Neotropical biomes: Amazonian rainforest and Uruguayan grasslands. We then tested how the cover of agriculture, pasture, urbanization and afforestation affected the taxonomic richness and functional diversity of those three species assemblages, and the consequences of these effects for animal biomass production. Single trait categories and functional diversity were evaluated, combining recruitment and life‐history, resource and habitat‐use, and body size.The effects of intensive human land‐uses on taxonomic and functional diversities were as strong as other drivers known to affect biodiversity, such as local climate and environmental factors. In both biomes, the taxonomic richness and functional diversity of animal and macrophyte assemblages decreased with increasing cover of agriculture, pasture, and urbanization. Human land‐uses were associated with functional homogenization of both animal and macrophyte assemblages. Human land‐uses reduced animal biomass through direct and indirect pathways mediated by declines in taxonomic and functional diversities.Our findings indicate that converting natural ecosystems to supply human demands results in species loss and trait homogenization across multiple biotic assemblages, ultimately reducing animal biomass production in streams. [ABSTRACT FROM AUTHOR]

Rivers suffer from multiple stressors acting simultaneously on their biota, but the consequences are poorly quantified at the global scale. We evaluated the biological condition of rivers globally, including the largest proportion of countries from the Global South published to date. We gathered macroinvertebrate‐ and fish‐based assessments from 72,275 and 37,676 sites, respectively, from 64 study regions across six continents and 45 nations. Because assessments were based on differing methods, different systems were consolidated into a 3‐class system: Good, Impaired, or Severely Impaired, following common guidelines. The proportion of sites in each class by study area was calculated and each region was assigned a Köppen‐Geiger climate type, Human Footprint score (addressing landscape alterations), Human Development Index (HDI) score (addressing social welfare), % rivers with good ambient water quality, % protected freshwater key biodiversity areas; and % of forest area net change rate. We found that 50% of macroinvertebrate sites and 42% of fish sites were in Good condition, whereas 21% and 29% were Severely Impaired, respectively. The poorest biological conditions occurred in Arid and Equatorial climates and the best conditions occurred in Snow climates. Severely Impaired conditions were associated (Pearson correlation coefficient) with higher HDI scores, poorer physico‐chemical water quality, and lower proportions of protected freshwater areas. Good biological conditions were associated with good water quality and increased forested areas. It is essential to implement statutory bioassessment programs in Asian, African, and South American countries, and continue them in Oceania, Europe, and North America. There is a need to invest in assessments based on fish, as there is less information globally and fish were strong indicators of degradation. Our study highlights a need to increase the extent and number of protected river catchments, preserve and restore natural forested areas in the catchments, treat wastewater discharges, and improve river connectivity. [ABSTRACT FROM AUTHOR]

The Mariana disaster, resulting from the rupture of the Fundão tailings storage facility (TSF) in 2015, was a large‐scale environmental disaster that drastically affected the entire channel of the Rio Doce, southeastern Brazil. The disaster produced substantial channel siltation, increased turbidity, riparian damage and a massive fish kill. However, the Rio Doce basin has a long history of environmental degradation, including hydroelectric dams. The latter are major threats to the ichthyofauna because they affect flow regimes, trap sediments and large wood, select generalist species, impair fish migrations and favour non‐native invasive species. In this study, we analysed the effects of the rupture as well as impacts from the construction of a run‐of‐the‐river hydroelectric dam on native and non‐native fish abundances, and species richness and composition in the middle Rio Doce.To do this, we examined fish survey data collected before and after each disturbance upriver of the reservoir, in the reservoir area and downriver of the dam. The data were separated into three temporal intervals: free‐flowing river, post‐filling reservoir and post‐TSF disaster. To assess temporal changes in native and non‐native fish species richness, we used a rarefaction method and tested it with two‐way ANOVA, which also was used to compare fish abundances. To test temporal changes in fish assemblage composition we used a PERMANOVA test.We observed no significant differences in total native or non‐native species richness as a result of the dam or the disaster. However, we did observe increased non‐native individual abundances after the TSF rupture as well as native individual abundances, depending on the location studied. The assemblage composition also changed after dam construction and the TSF rupture, except for the upriver reach after dam construction.We conclude that both the dam and the TSF rupture affected fish assemblages, favouring increased non‐native abundances, and also changed fish assemblage composition.Our results suggest that a century of landscape and riverscape pressures had extirpated the sensitive fishes from the Rio Doce before the TSF rupture. We conclude that multiple long‐term chronic disturbances can be as harmful to aquatic biota as the acute effects of a major environmental disaster. [ABSTRACT FROM AUTHOR]

Biological monitoring is important for assessing the ecological condition of surface waters. However, there are challenges in determining what constitutes reference conditions, what assemblages should be used as indicators, and how assemblage data should be converted into quantitative indicator scores. In this study, we developed and applied biological condition gradient (BCG) modeling to fish and macroinvertebrate data previously collected from large, sandy bottom southwestern USA rivers. Such rivers are particularly vulnerable to altered flow regimes resulting from dams, water withdrawals and climate change. We found that sensitive ubiquitous taxa for both fish and macroinvertebrates had been replaced by more tolerant taxa, but that the condition assessment ratings based on fish and macroinvertebrate assemblages differed. We conclude that the BCG models based on both macroinvertebrate and fish assemblage condition were useful for classifying the condition of southwestern USA sandy bottom rivers. However, our fish BCG model was slightly more sensitive than the macroinvertebrate model to anthropogenic disturbance, presumably because we had historical fish data, and because fish may be more sensitive to dams and altered flow regimes than are macroinvertebrates. [ABSTRACT FROM AUTHOR]

Rivers vary because of their different geographic settings and their differing levels of anthropogenic disturbances. Relative to wadeable streams, boatable or raftable rivers are much less studied because they require more expensive gear and are more dangerous to sample. Because of the importance of Pacific Northwest rivers for water supply, recreation, and endangered fish species, we selected seven rivers of interest to state, tribal, or federal agencies. Our objectives were to determine the degree to which fish and macroinvertebrate assemblages varied with water quality, habitat structure, and distance along each river, as well as the degree to which each river differed from the others. We sampled the rivers by inflatable rafts and assessed spatial patterns in fish and macroinvertebrate assemblages as well as water quality and physical habitat structure at 20 sites spread out longitudinally along each river. By analyzing site‐to‐site similarity matrices for fish, macroinvertebrates, chemistry, habitat, and river distance, we found that water quality‐river distance relationships were relatively strong, but habitat structure‐distance relationships were usually weak or absent. Also, site‐to‐site similarity in water quality was unrelated to the site‐to‐site similarity in habitat structure. Among‐river variability was much greater than within‐river variability for both fish and macroinvertebrate assemblages. We observed very different patterns among the seven rivers regarding the importance of distance, water quality, and physical habitat similarities relative to fish and macroinvertebrate assemblage similarities. The best set of environmental variables for distinguishing biotic assemblage similarities varied widely among rivers, and among the two assemblage types. We conclude that the riverscape concept is valuable for river monitoring, research, and management, as well as the value of rigorously sampling both water quality and physical habitat as well as both fish and macroinvertebrate assemblages. [ABSTRACT FROM AUTHOR]

Conditions in freshwater ecosystems are responsible for maintaining biodiversity and other ecosystem services. Identifying and understanding how anthropogenic disturbances affect biotic conditions are important steps in rehabilitating and protecting environmental quality. The relative risk, relative extent, and attributable risk approaches are used to determine ecosystem conditions in ecological monitoring programs conducted across large spatial extents. Our study was conducted in the Pandeiros River basin, which is a protected area in Minas Gerais, Brazil, that contains 233 km of mapped streams that were perennial and accessible. Field sampling was conducted in the dry period (April and June 2016) at 40 randomly selected sites. Ten multimetric indices (MMIs), previously determined to be sensitive in this river basin, were calculated. All the physical habitat disturbance metrics were significantly correlated with the MMIs. The risk of finding poor MMI scores was 1.6–1.7 times higher at sites with a high integrated disturbance index (IDI) or local disturbance index (LDI) score. Pasture was the most extensive disturbance, affecting 40.8% of the stream length, followed by 40.1% for low bed stability, 29% for fine substrates (<16 mm), 24.4% for high IDI scores, and 21.7% for high LDI scores. This is useful to know for five reasons: (1) standardized MMIs can assess environmental quality. (2) MMIs clarify that both catchment and local disturbances may represent serious risks to aquatic assemblages. (3) MMIs indicate which disturbances represent the most risk by comparing MMI scores against disturbance scores. (4) MMI risk assessments facilitate choosing the most appropriate mitigation actions. (5) Our results suggest environmental conservation actions for similar river basins. [ABSTRACT FROM AUTHOR]

Over 70% of the total channel length in all river basins is formed by low order streams, many of which originate on mountaintops. Headwater streams play fundamental roles in processing and transporting terrestrial and aquatic organic matter, often harboring high biodiversity in bottom leaf patches deposited from riparian vegetation. The objective of this study was to assess the variation in taxonomic composition (measured by beta diversity of aquatic macroinvertebrates) among stream sites located in the Espinhaço Meridional Mountain Range, part of a UNESCO Biosphere Reserve in eastern Brazil. We tested two hypotheses. (a) Taxa turnover is the main reason for differences in aquatic insect assemblages within stream sites; we predicted that turnover would be higher than nestedness in all stream sites. (b) Stream site altitude and catchment elevation range are the main explanatory variables for the differences in beta diversity; we predicted that local stream site variables would account for only minor amounts of variation. In both dry and wet seasons, we sampled twice in two habitat types (five leaf patches in pools and five in riffles) in each of nine stream sites distributed in three different river basins. We computed average pairwise beta diversity among sampling stations and seasons in each stream site by using Jaccard and Bray–Curtis indices, and calculated the percentages of diversity resulting from turnover and nestedness. Finally, we tested the degree that local‐ or catchment‐level predictor variables explained beta diversity. We found that turnover was the main component of beta diversity and that both dissolved oxygen and elevation range best explained Bray–Curtis beta diversity. These results reinforce the importance of leaf patches in montane (sky islands) Neotropical savanna streams as biodiversity hotbeds for macroinvertebrates, and that both local and landscape variables explained beta diversity. [ABSTRACT FROM AUTHOR]

Because of mineral mining threats in the headwaters that drain into Lake Clark National Park, we implemented a baseline ecological survey of the Chulitna River basin through the use of a probability study design. A total of 49 wadeable stream and raftable river sites were sampled for fish assemblages, multiple physical habitat structure variables, and multimeter chemistry (dissolved oxygen, conductivity, pH, and water temperature) by the using standard methods that are employed in the United States Environmental Protection Agency's (USEPA) National Rivers and Streams Assessment. We recorded moderate levels of canopy density, low levels of riparian woody vegetation cover, and the absence of large wood in the Chulitna River basin streams. The extremely low levels of channel incision, the absence of riparian anthropogenic disturbance, and high levels of water quality indicate insignificant anthropogenic landscape alteration in these streams and rivers. Fish were not observed at seven sites, representing 27% of the calculated 2,220 km of the target stream length in the study population. Arctic Grayling Thymallus arcticus, Dolly Varden Salvelinus malma, and Northern Pike Esox lucius were present in 10% (227 km), 38% (847 km), and 8% (181 km) of the calculated target stream/river length, respectively. The most commonly occurring and abundant species, Slimy Sculpin Cottus cognatus (now Uranidea cognata), was present in 56% (1,244 km) of the calculated stream/river length. The lack of anadromous salmon detections was associated with salmonid life histories, naturally high levels of substrate fines and embeddedness, and the presence of Northern Pike. The quality of physical habitat and water quality, as well as the occurrences of Arctic Grayling and Dolly Varden, are representative of the unimpaired waters in Alaska, compared with those in the conterminous USA. We concluded that statistically and ecologically rigorous stream and river sampling can be implemented across a roadless region at reasonable cost and with sufficient planning. [ABSTRACT FROM AUTHOR]

Hydropower dams substantially modify lotic ecosystems. Most studies regarding their ecological impacts are based on large dams and provide little information about the far more abundant effects of small hydropower dams. Our aim was to characterize the ecological effects of a small hydropower dam and run‐of‐the‐river reservoir on the structure of benthic macroinvertebrate assemblages in the Pandeiros River located in the neotropical savanna of Brazil. We tested the hypothesis that benthic macroinvertebrate assemblages in sites directly affected by the dam and reservoir would show a different taxonomic structure compared with those in free‐flowing sites. We expected to find sensitive native species associated with the free‐flowing sites, whereas resistant and non‐native invasive taxa were expected in impounded sites. We also explored associations between the presence of native and non‐native invasive taxa to each habitat type. We found that the structure of benthic macroinvertebrate assemblages was significantly different between free‐flowing and impounded sites. Also, we found that the dam and reservoir facilitated colonization of non‐native invasive species (Corbicula fluminea and Melanoides tuberculata) because only in those sites they were found in high abundance, in contrast to the free‐flowing sites. Although the environmental conditions imposed by the impoundment altered the structure of benthic macroinvertebrate assemblages, the effects were limited to sites closest to the dam. Our results highlight the necessity of understanding physical habitat changes caused by the presence and management of run‐of‐the‐river dams and reservoirs. [ABSTRACT FROM AUTHOR]

Highlights • Adolescent BZP treatment and enrichment affect anxiety at older ages in rats. • Enrichment enhances anxiogenic effects at older ages of adolescent BZP treatment. • Adolescent BZP treatment does not seem to affect spatial memory development. • Adolescent BZP effects at older ages can depend on sex and age of testing. Abstract From 30 days after birth until the completion of the study, male and female rats were caged in same-sexed twos or threes either with (enriched cages, EC) or without several objects for them to explore (standard cages, SC). From 41 to 50 days of age (late adolescence), they received a daily intraperitoneal injection of saline, or 10 or 20 mg/kg of the monoaminergic agonist drug of abuse, 1-benzylpiperazine (BZP). Ten days later (PND60+), their behavior was observed over several days in an open field, an elevated plus maze, a light-dark box and (to assess short-term memory) a Y maze in which one of the arms had been changed in brightness between two trials. These tests were repeated from 40 days after PND60+, namely PND100+. While open-arm occupancy at PND100+ in the plus maze was lower following both doses of the drug for SC rats only, other examples of BZP-related heightened anxiety were confined to EC rats. This suggested that enrichment had enhanced rather than reduced any anxiogenic effects of the drug treatment. There was no plausible evidence of BZP-associated impaired spatial memory required to recognize the changed novel Y-maze arm. Instead, changes in novelty preferences or neophobia-related anxiety were most likely. While there were also some examples of sex and age differences in the later effects of BZP, in most cases these were evident at both ages following treatment with both BZP doses. A number of overall BZP, cage, sex and age differences, independent of enrichment effects, were also observed. [ABSTRACT FROM AUTHOR]

Protein fusions are of fundamental importance in the study of cellular biology and the elucidation of cell signaling pathways, and the importance of linkers for the proper function of protein fusions is well documented in the literature. However, there are few convenient methods available to experimentalists for the systematic implementation of linkers in protein fusions. In this work, we describe a universal approach to the creation and insertion of focused linker libraries into protein fusions. This process, deemed protaTETHER, utilizes reiterative oligomer design, PCR‐mediated linker library generation, and restriction enzyme‐free cloning methods in a straightforward, three‐step cloning process. We utilize a fusion between the catalytic subunit of cAMP‐dependent protein kinase A (PKAc) and green fluorescent protein (GFP) for the development of the protaTETHER method, implementing small linker libraries that vary by length, sequence, and predicted secondary structural elements. We analyze the impact of linker length and sequence on the expression, activity, and subcellular localization of the PKAc‐GFP fusions, and use these results to select a PKAc‐GFP fusion construct with robust expression and enzymatic activity. Based upon the results of both biochemical experiments and molecular modeling, we determine that linker flexibility is more important than linker length for optimal kinase activity and expression. [ABSTRACT FROM AUTHOR]

Galvanic replacement reactions are widely used in the synthesis of bimetallic nanoshells. Essential to these syntheses is the design of template materials with electrochemical potentials that are low enough to facilitate the replacement of a wide variety of metals. While Cu is an attractive template from this standpoint, it has only rarely been used due to its propensity for oxidation and the associated difficulties in achieving chemically stable colloids. Here, a synthetic scheme is demonstrated for the design of supported Cu templates and their subsequent replacement with Rh where the detrimental influences of oxidation are not only mitigated but used to place shape and compositional controls on the reaction product. It is shown that the CuRh nanoshells can be produced that are shaped as substrate-truncated nanocubes or cuboctahedrons depending upon the degree of exposure that the Cu templates have to dissolved oxygen. Moreover, it is demonstrated that the intentional surface oxidation of the Cu template followed by Cu2O removal results in galvanic replacement reactions yielding porous nanoshells with far greater Rh replacement. The study forwards the design of Cu templates for galvanic replacement reactions and presents opportunities for their use in other template-mediated syntheses. [ABSTRACT FROM AUTHOR]

Abstract: Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human‐induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna. To assess the extent to which stream fish are being effectively conserved in agricultural landscapes, we examined the spatial distribution of assemblages in river basins to identify the relative importance of human impacts at instream, riparian and catchment scales, in shaping observed patterns. We used an extensive dataset on the ecological condition of 83 low‐order streams distributed in three river basins in the eastern Brazilian Amazon. We collected and identified 24,420 individual fish from 134 species. Multiplicative diversity partitioning revealed high levels of compositional dissimilarity (DS) among stream sites (DS = 0.74 to 0.83) and river basins (DS = 0.82), due mainly to turnover (77.8% to 81.8%) rather than nestedness. The highly heterogeneous fish faunas in small Amazonian streams underscore the vital importance of enacting measures to protect forests on private lands outside of public protected areas. Instream habitat features explained more variability in fish assemblages (15%–19%) than riparian (2%–12%), catchment (4%–13%) or natural covariates (4%–11%). Although grouping species into functional guilds allowed us to explain up to 31% of their abundance (i.e. for nektonic herbivores), individual riparian – and catchment – scale predictor variables that are commonly a focus of environmental legislation explained very little of the observed variation (partial R2 values mostly <5%). Policy implications. Current rates of agricultural intensification and mechanization in tropical landscapes are unprecedented, yet the existing legislative frameworks focusing on protecting riparian vegetation seem insufficient to conserve stream environments and their fish assemblages. To safeguard the species‐rich freshwater biota of small Amazonian streams, conservation actions must shift towards managing whole basins and drainage networks, as well as agricultural practices in already‐cleared land. [ABSTRACT FROM AUTHOR]

Agricultural land use is a primary driver of environmental impacts on streams. However, the causal processes that shape these impacts operate through multiple pathways and at several spatial scales. This complexity undermines the development of more effective management approaches, and illustrates the need for more in-depth studies to assess the mechanisms that determine changes in stream biodiversity. Here we present results of the most comprehensive multi-scale assessment of the biological condition of streams in the Amazon to date, examining functional responses of fish assemblages to land use. We sampled fish assemblages from two large human-modified regions, and characterized stream conditions by physical habitat attributes and key landscape-change variables, including density of road crossings (i.e. riverscape fragmentation), deforestation, and agricultural intensification. Fish species were functionally characterized using ecomorphological traits describing feeding, locomotion, and habitat preferences, and these traits were used to derive indices that quantitatively describe the functional structure of the assemblages. Using structural equation modeling, we disentangled multiple drivers operating at different spatial scales, identifying causal pathways that significantly affect stream condition and the structure of the fish assemblages. Deforestation at catchment and riparian network scales altered the channel morphology and the stream bottom structure, changing the functional identity of assemblages. Local deforestation reduced the functional evenness of assemblages (i.e. increased dominance of specific trait combinations) mediated by expansion of aquatic vegetation cover. Riverscape fragmentation reduced functional richness, evenness and divergence, suggesting a trend toward functional homogenization and a reduced range of ecological niches within assemblages following the loss of regional connectivity. These results underscore the often-unrecognized importance of different land use changes, each of which can have marked effects on stream biodiversity. We draw on the relationships observed herein to suggest priorities for the improved management of stream systems in the multiple-use landscapes that predominate in human-modified tropical forests. [ABSTRACT FROM AUTHOR]

The type of fat used in formulating broiler chicken diets can affect growth performance, influence the fatty acid composition of different tissues and has consequences for bird health and nutritional value for the consumer. This study aimes to address the hypothesis of whether these effects are specifically due to the variation in the fatty acid composition of the diets, that is, the proportion of different saturates, monounsaturates (n-7 and n-9) or polyunsaturates (n-3 or n-6), or other factors (physical properties, solid/liquid and source, plant/animal). A total of 480 male Cobb 500 broilers are fed ad libitum on one of six diets containing 4% w/w of either: beef tallow, flaxseed, corn, canola, macadamia, or coconut oil (eight replicates/treatment) for 6 weeks. At harvest, there are no significant differences in productivity parameters nor in the crude lipid content of different tissues between dietary treatments. There are, however, substantial qualitative differences in the fatty acid profiles of all tissues. The levels of specific fatty acids in all tissues except the brain, are positively correlated with the levels of the same fatty acids in the diet however, the strength of the correlations varied between different fatty acids. Practical Applications: The results of the current study demonstrate that the dietary fatty acids types and proportions largely determines the fatty acid profile in edible tissues (meat, adipose, liver, and heart). The strong correlations and regressions between diet and tissue fatty acid levels validate the ability to predict the tissue fatty acid profile of broilers based on their dietary fat composition. Contrary to our hypothesis, dietary fat type had no influence on the growth parameters which makes us speculate whether such differences in similar studies only become apparent in situations where the birds are also under some level of environmental or social stress. This information will assist poultry feed manufacturers and broiler producers in making decisions about selection of fats with known nutritional and health benefits for inclusion in chicken feed. The relationship between the diet and breast meat fatty acid composition of 6-week-old male broilers (Cobb 500) fed diets containing 4% w/w of either tallow, flaxseed oil, corn oil, canola oil, macadamia oil, or coconut oil. Dietary fatty acid intake determined breast meat fatty acid composition with a strong positive linear correlation for 6 all fatty acid groups (saturates, omega-9 and omega-7 monounsaturates, omega-3, and omega-6 polyunsaturates and trans, R = 0.938-0.999, P < 0.01). [ABSTRACT FROM AUTHOR]

It is widely held that single-word lexical access is a competitive process, a view based largely on the observation that naming a picture is slowed in the presence of a distractor-word. However, problematic for this view is that a low-frequency distractor-word slows the naming of a picture more than does a high-frequency word. This supports an alternative, response-exclusion, account in which a distractor-word interferes because it must be excluded from an articulatory output buffer before the right word can be articulated (the picture name): A high, compared to low, frequency word accesses the buffer more quickly and, as such, can also be excluded more quickly. Here we studied the respective roles of competition and response-exclusion for the first time in the context of semantic verbal fluency, a setting requiring the accessing of, and production of, multiple words from long-term memory in response to a single semantic cue. We show that disruption to semantic fluency by a sequence of to-be-ignored spoken distractors is also greater when those distractors are low in frequency, thereby extending the explanatory compass of the response-exclusion account to a multiple-word production setting and casting further doubt on the lexical-selection-by-competition view. The results can be understood as reflecting the contribution of speech output processes to semantic fluency. [ABSTRACT FROM AUTHOR]

A strategy for the light-activated release of bioactive compounds (BODIPY, colchicine, paclitaxel, and methotrexate) from membrane-enclosed depots is described. We have found that membrane-permeable bioagents can be rendered membrane impermeable by covalent attachment to cobalamin (Cbl) through a photocleavable linker. These Cbl-bioagent conjugates are imprisoned within lipid-enclosed compartments in the dark, as exemplified by their retention in the interior of erythrocytes. Subsequent illumination drives the secretion of the bioactive species from red blood cells. Photorelease is triggered by wavelengths in the red, far-red, and near-IR regions, which can be pre-assigned by affixing a fluorophore with the desired excitation wavelength to the Cbl-bioagent conjugate. Pre-assigned wavelengths allow different biologically active compounds to be specifically and unambiguously photoreleased from common carriers. [ABSTRACT FROM AUTHOR]

Streams are under environmental pressures acting at different scales that influence the ecological organisation of their fish assemblages. However, the relative influence of the different scale-related variables on assemblage composition and function is poorly understood. We evaluated the importance of local- and catchment-scale environmental variables, as well as the spatial structure of the sampling sites, in shaping fish assemblages in Atlantic Forest streams. Local-scale variables were those measured at the sampling sites, describing the local habitat conditions (e.g. depth, substrate type, altitude). Catchment-scale variables were those integrating the upstream landscape of the sampling sites (e.g. catchment land use). Spatial distances were calculated from watercourse distance using principal coordinates of neighbour matrices. Altogether, 28 local and seven catchment variables were initially subjected to two processes of eliminating co-linearity. Redundancy analysis was applied to the three matrices (spatial, local and catchment) to quantify the variance in the structure of the fish assemblages explained by each matrix. Local variables explained more variability in both taxonomic and functional assemblage structure, than catchment and spatial variables. Local variables also changed along the longitudinal gradient, which consequently influenced fish assemblage structure. This pattern was also influenced by anthropogenic alteration and non-native species, which were more abundant in downstream sites. These results highlight the need to assess Atlantic Forest streams under different environmental scales, especially through the use of quantitative local-scale metrics, and to consider the effects of longitudinal patterns in structuring fish assemblages when developing and implementing monitoring programmes, impact studies and conservation plans. [ABSTRACT FROM AUTHOR]

Model organisms subject to dietary restriction ( DR) generally live longer. Accompanying this lifespan extension are improvements in overall health, based on multiple metrics. This indicates that pharmacological treatments that mimic the effects of DR could improve health in humans. To find new chemical structures that extend lifespan, we screened 30 000 synthetic, diverse drug-like chemicals in Caenorhabditis elegans and identified several structurally related compounds that acted through DR mechanisms. The most potent of these NP1 impinges upon a food perception pathway by promoting glutamate signaling in the pharynx. This results in the overriding of a GPCR pathway involved in the perception of food and which normally acts to decrease glutamate signals. Our results describe the activation of a dietary restriction response through the pharmacological masking of a novel sensory pathway that signals the presence of food. This suggests that primary sensory pathways may represent novel targets for human pharmacology. [ABSTRACT FROM AUTHOR]

Following a four-year period of writing, member comment, and multiple revisions, the AFS Position Paper and Policy on Mining and Fossil Fuel Extraction was approved unanimously by the membership at the Society's annual business meeting August 19, 2015, in Portland, Oregon. The entire document can be read atfisheries.org/policy_statements; a brief summary follows. [ABSTRACT FROM AUTHOR]

The thermal expansion behavior of the orthorhombic phase in the Ln2TiO5 (Ln = La, Nd, Gd, Dy, and Y) system was evaluated, using synchrotron X-ray diffraction from room temperature to approximately 1500°C in air. The components of the thermal expansion tensor were calculated from the refined d-spacings, using the program CTEAS. Subsequent analysis of the thermal expansion and crystallographic information revealed that the mechanism behind the thermal expansion was a result of strained trigonal-bipyramidal structures overcoming an energy barrier to become more relaxed. The temperature at which a significant shift in the trigonal-bipyramidal structure manifests was correlated with the size of the rare-earth cation that dictates the volume of the overall cell. Larger rare-earth cations with larger cell volumes allow more room for the trigonal-bipyramidal structures to easily relax. [ABSTRACT FROM AUTHOR]

An optogenetic Bax has been designed that facilitates light-induced apoptosis. We demonstrate that mitochondrial recruitment of a genetically encoded light-responsive Bax results in the release of mitochondrial proteins, downstream caspase-3 cleavage, changes in cellular morphology, and ultimately cell death. Mutagenesis of a key phosphorylatable residue or modification of the C-terminus mitigates background (dark) levels of apoptosis that result from Bax overexpression. The mechanism of optogenetic Bax-mediated apoptosis was explored using a series of small molecules known to interfere with various steps in programmed cell death. Optogenetic Bax appears to form a mitochondrial apoptosis-induced channel analogous to that of endogenous Bax. [ABSTRACT FROM AUTHOR]

Sensitive and cost-effective indicators of aquatic ecosystem condition in Amazon streams are necessary to assess the effects of anthropogenic disturbances on those systems in a viable and ecologically meaningful manner. We conducted the present study in the municipality of Paragominas, state of Pará, northern Brazil, where we sampled adult dragonflies in 50 100-m-long wadeable stream sites in 2011. We collected 1769 specimens represented by 11 families, 41 genera and 97 species. The suborder Zygoptera contributed 961 individuals and Anisoptera 808. Among the 97 recorded species, nine were classified as useful indicators of ecological condition, with four species being associated with more degraded streams (three Anisoptera, one Zygoptera) and five with more preserved streams (all were Zygoptera). Anisoptera (dragonflies) tend to provide more useful indicators of more degraded environments because they have more efficient homeostatic mechanisms and are more mobile, enabling them to tolerate a wider range of environmental conditions. By contrast, Zygoptera (damselflies) tend to provide a more useful role as indicators of more preserved environments and high levels of environmental heterogeneity because of their smaller body sizes and home ranges and greater ecophysiological restrictions. We conclude from our assessment of this low-order Amazonian stream system that (i) the occurrence of specific odonate species is strongly associated with the configuration of riparian vegetation, (ii) agricultural activities appear to be the main factor determining changes in the composition of odonate assemblages and (iii) these insects can act as useful indicators of the ecological consequences of riparian habitat loss and disturbance. Because generalist species invade moderately degraded areas, those areas may have high species richness but host few species of Zygoptera. Therefore, preserving dense riparian vegetation is necessary to maintain aquatic ecological condition, and that condition can be rehabilitated by planting new trees. Both require enforcing existing environmental regulations, various types of incentives and educating local communities. [ABSTRACT FROM AUTHOR]

Genetically encoded, light-activatable proteins provide the means to probe biochemical pathways at specific subcellular locations with exquisite temporal control. However, engineering these systems in order to provide a dramatic jump in localized activity, while retaining a low dark-state background remains a significant challenge. When placed within the framework of a genetically encodable, light-activatable heterodimerizer system, the actin-remodelling protein cofilin induces dramatic changes in the F-actin network and consequent cell motility upon illumination. We demonstrate that the use of a partially impaired mutant of cofilin is critical for maintaining low background activity in the dark. We also show that light-directed recruitment of the reduced activity cofilin mutants to the cytoskeleton is sufficient to induce F-actin remodeling, formation of filopodia, and directed cell motility. [ABSTRACT FROM AUTHOR]

Phase transition and high-temperature properties of rare-earth niobates (LnNbO4, where Ln = La, Dy and Y) were studied in situ at high temperatures using powder X-ray diffraction and thermal analysis methods. These materials undergo a reversible, pure ferroelastic phase transition from a monoclinic (S.G. I2/a) phase at low temperatures to a tetragonal (S.G. I41/a) phase at high temperatures. While the size of the rare-earth cation is identified as the key parameter, which determines the transition temperature in these materials, it is the niobium cation which defines the mechanism. Based on detailed crystallographic analysis, it was concluded that only distortion of the NbO4 tetrahedra is associated with the ferroelastic transition in the rare-earth niobates, and no change in coordination of Nb5+ cation. The distorted NbO4 tetrahedron, it is proposed, is energetically more stable than a regular tetrahedron (in tetragonal symmetry) due to decrease in the average Nb-O bond distance. The distortion is affected by the movement of Nb5+ cation along the monoclinic b-axis (tetragonal c-axis before transition), and is in opposite directions in alternate layers parallel to the (010). The net effect on transition is a shear parallel to the monoclinic [100] and a contraction along the monoclinic b-axis. In addition, anisotropic thermal expansion properties and specific heat capacity changes accompanying the transition in the studied rare-earth niobate systems are also discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT It is widely agreed that foreign sponsors of research in low- and middle-income countries (LMICs) are morally required to ensure that their research benefits the broader host community. There is no agreement, however, about how much benefit or what type of benefit research sponsors must provide, nor is there agreement about what group of people is entitled to benefit. To settle these questions, it is necessary to examine why research sponsors have an obligation to benefit the broader host community, not only their subjects. Justifying this claim is not straightforward. There are three justifications for an obligation to benefit host communities that each apply to some research, but not to all. Each requires a different amount of benefit, and each requires benefit to be directed toward a different group. If research involves significant net risk to LMIC subjects, research must provide adequate benefit to people in LMICs to avoid an unjustified appeal to subjects' altruism. If research places significant burdens on public resources, research must provide fair compensation to the community whose public resources are burdened. If research is for profit, research sponsors must contribute adequately to the upkeep of public goods from which they benefit in order to avoid the wrong of free-riding, even if their use of these public goods is not burdensome. [ABSTRACT FROM AUTHOR]

Light-activatable drugs offer the promise of controlled release with exquisite temporal and spatial resolution. However, light-sensitive prodrugs are typically converted to their active forms using short-wavelength irradiation, which displays poor tissue penetrance. We report herein erythrocyte-mediated assembly of long-wavelength-sensitive phototherapeutics. The activating wavelength of the constructs is readily preassigned by using fluorophores with the desired excitation wavelength λex. Drug release from the erythrocyte carrier was confirmed by standard analytical tools and by the expected biological consequences of the liberated drugs in cell culture: methotrexate, binding to intracellular dihydrofolate reductase; colchicine, inhibition of microtubule polymerization; dexamethasone, induced nuclear migration of the glucocorticoid receptor. [ABSTRACT FROM AUTHOR]

Phase transition and high-temperature properties of rare-earth niobates (LnNbO4, where Ln = La, Dy and Y) were studied in situ at high temperatures using powder X-ray diffraction and thermal analysis methods. These materials undergo a reversible, pure ferroelastic phase transition from a monoclinic (S.G. I2/a) phase at low temperatures to a tetragonal (S.G. I41/a) phase at high temperatures. While the size of the rare-earth cation is identified as the key parameter, which determines the transition temperature in these materials, it is the niobium cation which defines the mechanism. Based on detailed crystallographic analysis, it was concluded that only distortion of the NbO4 tetrahedra is associated with the ferroelastic transition in the rare-earth niobates, and no change in coordination of Nb5+ cation. The distorted NbO4 tetrahedron, it is proposed, is energetically more stable than a regular tetrahedron (in tetragonal symmetry) due to decrease in the average Nb-O bond distance. The distortion is affected by the movement of Nb5+ cation along the monoclinic b-axis (tetragonal c-axis before transition), and is in opposite directions in alternate layers parallel to the (010). The net effect on transition is a shear parallel to the monoclinic [100] and a contraction along the monoclinic b-axis. In addition, anisotropic thermal expansion properties and specific heat capacity changes accompanying the transition in the studied rare-earth niobate systems are also discussed. [ABSTRACT FROM AUTHOR]

The thermal expansion ( TE) behavior of cubic and rhombohedral Ln6 WO12 (Ln = Y, Ho, Er, Yb) and monoclinic Ln2 WO6 (Ln = Gd, Dy, Ho) was investigated by synchrotron X-ray diffraction from room temperature to approximately 1500°C. The volumetric and lattice parameter expansions were measured for all compositions in both systems, and the respective expansion coefficients were derived and fitted over the observed temperature range with a second-order polynomial. The relative TE evolution along the unit cell edges in each phase was described from a crystallographic perspective, with the reasons for TE dynamics explained in terms of the fundamental constituent units of the structure. Analysis of the TE ellipsoid of the monoclinic Ln2 WO6 revealed a continuous change in both its shape and orientation, with the latter effect strongly manifested in the (010) plane. A noticeable reversal of the relative expansion rates between a, and b and c lattice parameters was attributed to the rotation of the ellipsoid cross section in this plane, bringing the larger of the two eigenvectors closer to a, while the smaller one to c. Investigating the structural dynamics of the constituent layers in Ln2 WO6 suggested that the bridging role of the Ln polyhedron centered on the only general position in the unit cell may be the reason for the rotating TE ellipsoid. [ABSTRACT FROM AUTHOR]

The high-temperature rhombohedral-to-fcc phase transformation in the Ln6WO12 (Ln = Y, Ho, Er, Yb) system was investigated by thermal analysis and in situ X-ray diffraction. The process was characterized by thermodynamic, kinetic, and mechanistic criteria, and the role of the rare-earth cation on the transformation properties trends was evaluated. An atomistic perspective on the accompanying structural change is presented, as well as a characterization of the associated shape and volume changes. A twofold comparison is performed with the similar low-temperature fcc-to-rhombohedral transformation in the same system. One aspect contrasts the structural changes related to each process, manifested by the behavior of the lattice parameters and transformation characteristics. The second concerns the sequence of transformations according to composition and suggests the order of thermal stability of Ln polyhedra in each phase. [ABSTRACT FROM AUTHOR]

Previously we examined how degraded urban streams can be rehabilitated, with emphasis on identifying solutions that match the scale of the problems (Hughes et al. 2014). Our findings showed that rehabilitation techniques are challenging but that some environmental benefits can nearly always be obtained regardless of existing conditions. Although rehabilitation is useful in many present‐day situations, biologists need to consider the future and think about ways of preventing or reducing future environmental damage. We need to reduce future damage because urban areas are likely to expand greatly over the next century; if historical patterns continue, the number and length of streams experiencing urban stream syndrome will increase, with resulting high repair costs. However, there are several ways of avoiding or mitigating damage that are not only cost effective but provide benefits to humans and urban ecosystems. RESUMEN: previamente se examinó cómo los ríos urbanos degradados pueden ser rehabilitados, con énfasis en la identificación de soluciones consistentes con la escala de los problemas. Los hallazgos mostraron que las técnicas de rehabilitación si bien presentan un reto, casi siempre puede obtenerse un margen de beneficios ambientales indepen‐dientemente de las condiciones imperantes. Pese a que la rehabilitación puede ser útil en muchas de las situaciones actuales, los biólogos necesitan tomar en cuenta el futuro e idear formas para prevenir o reducir el daño ambiental. Esta reducción resulta indispensable toda vez que se espera que las áreas urbanas se expandan de forma importante en el siguiente siglo; de continuar los patrones históricos, se incrementará el número y extensión de los caudales que sufren del síndrome del río urbano, lo que dará como resultado elevados costos de reparación. No obstante, existen diversas formas para evitar o mitigar los daños; formas que no solo son efectivas en términos de costos sino que también proveen beneficios tanto a los humanos como a los ecosistemas urbanos. [ABSTRACT FROM AUTHOR]