Large Species Research Articles

Integrating genetic and morphological data to assess species delimitation of two Japanese large abalones: Haliotis discus discus and H. madaka

Abstract Two large abalone species prevalent in the Japanese archipelago, Haliotis discus discus and H. madaka, are considered to have different morphological characteristics, and previous population genomics analyses have suggested that they have distinct genomic features. However, integrated analyses comparing the genetic and morphological data from these species are lacking; thus, it remains unclear whether these two species are distinct biological species. In this study, we performed integrated genetic and morphological analyses on individuals of the two species captured in Tokushima Prefecture, Japan. Genetic analysis based on 118 species-diagnostic single-nucleotide polymorphism (SNP) loci showed that H. discus discus and H. madaka were clearly assigned to distinct genetic clusters corresponding to the two species, with the exception of one H. madaka individual showing evidence of genomic introgression from H. discus discus. Multiple statistical analyses based on quantitative characteristics of shell shape and foot muscle color suggested that this H. madaka individual with genomic introgression from H. discus discus had H. discus discus-like quantitative characteristics consistently. In summary, this study suggests that H. discus discus and H. madaka are distinct biological species reproductively isolated in natural environments, but genomic introgression possibly blurs the species boundary between H. discus discus and H. madaka.

Trace element contaminants and endocrine status of European brown bears assessed using blood as a matrix.

Bioaccumulation of trace element contaminants with endocrine disruptive (ED) potential has been noted in European brown bears, though evidence of their effects is lacking. Generalized linear models were employed to assess circulating levels of reproductive, stress, and thyroid hormones in relation to arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and thallium (Tl) in 53 free-ranging brown bears (Ursus arctos) from two European populations (Carpathian and Dinara-Pindos). Other potential drivers of hormone variation, such as essential elements, ecological factors, physiological variables, and capture methods, were included as predictors. The models demonstrated a positive association between cortisol and Cd, and a negative association with Tl. In addition, Tl and Pb were identified as key factors in explaining variation in thyroid hormones (free triiodothyronine, fT3 and free thyroxine, fT4). Trap type was significant in explaining variation in fT3 concentrations, while sex was an important predictor of progesterone levels. The essential elements, cobalt (Co) and copper (Cu) accounted for 41% of testosterone variation, while Cu and selenium (Se) were negatively associated with fT4. Other notable predictors of investigated hormone variation included body condition index (important for cortisol), age (for fT4), year (for fT3), capture day (for fT4 and fT4:fT3 ratio) and population (fT4:fT3 ratio). This study evidenced trace elements as important factors to consider when studying hormonal variation in terrestrial wildlife (Tl for cortisol and fT3, Cd for cortisol, Cu for testosterone and fT4, Co for testosterone, Pb and Se for fT4). To gain a more definitive understanding of the effects of exposure to element contaminants on endocrine status, it is recommended to include more sensitive and specific endocrine disruption-related endpoints in a larger sample size. Doing so will further enhance our understanding of the potential adverse endocrine effects of environmental pollutants on these bear populations and other large mammalian wildlife species.

Impact of global environmental changes on the range contraction of Eurasian moose since the Late Pleistocene

Climatic oscillations are considered primary factors influencing the distribution of various life forms on Earth. Large species adapted to cold climates are particularly vulnerable to extinction due to the climate changes. In our study, we investigated whether the temperature increase since the Late Pleistocene and the contraction of environmental niche during the Holocene were the main factors contributing to the decreasing range of moose (Alces alces) in Europe. We also examined whether there were significant differences in environmental conditions between areas inhabited by moose in Europe and Asia, that could support the division of moose into western and eastern forms, as suggested by genetic and morphological data. We analysed environmental conditions in locations of 655 subfossil and modern moose occurrences over the past 50,000 years in Eurasia. We found that the most limiting climatic factor for the moose distribution since the Late Pleistocene was July temperature. >90 % of moose records were found in areas where the mean summer temperature was below 19 °C, with July temperatures showing over 3 times narrower interquartile range compared to January temperatures. We identified significant differences in environmental conditions between areas inhabited by the European and Asiatic moose. In Europe, the species occurred in regions with milder climates, higher primary productivity, and more frequently within forest biomes compared to Asiatic individuals. The moose range shifted more in the west-east than in the south-north direction during the Holocene climate warming in Europe. We concluded that although the area of suitable moose habitat has increased since 12–8 ka years BP, as demonstrated by environmental niche modeling, the retreat of A. alces in large areas of Europe was likely caused by anthropogenic landscape change (e.g., deforestation) and overhunting by humans during the late Holocene rather than by climate warming during the Pleistocene to Holocene transition.

Time since fire interacts with herbivore intake rates to control herbivore habitat occupancy.

Smaller grazers consistently show greater preference for recently burned patches than larger species. Energy optimization theory posits that this pattern is driven by small- versus large-bodied herbivores seeking to maximize energy intake by choosing high-quality recently burned grasses, or high-quantity unburned grasses, respectively. We propose that if burn preference is driven by an energy-maximization mechanism, then preference should change over time as grass regrows and progresses across the optimal feeding heights of herbivores of increasing body size. To test this, we used a camera trap array in the Serengeti National Park to quantify changes in the relative preference for burned patches of seven ruminant herbivore species. We compared observed patterns to simulation results from a grass production-herbivore patch selection model. Burn preference and herbivore body size scaled negatively for 6 months after fire, but this relationship disappeared after 7 months when smaller species stopped selecting burns, and larger herbivores selected burns after 10 months, in a reversal of classic grazer succession. Simulations recreated the former but not the latter relationship, suggesting that an energy-maximization mechanism can drive allometric scaling of burn preference immediately after fire, but over longer periods, grazer-driven feedbacks are required to explain large herbivore burn preferences.

Spatial Distribution of Calanoida in Freshwater Ecosystems and Their Application as a Food Web Assessment Index

Calanoida is a representative oligo-mesotrophic indicator species, frequently used as an index for assessing lake ecosystems’ health. Additionally, they function as trophic intermediates in the food web, connecting primary producers and higher consumers within lake ecosystems’ food chains. However, research cases that present the implications of habitat environment assessments, such as ecosystem structure and water quality, represented by these taxa remain insufficient. In this study, we conducted research across 49 lakes in South Korea, analyzing the occurrence characteristics of Calanoida and examining the correlations between Calanoida abundance and water quality parameters and the morphological-based functional groups of phytoplankton. Calanoida were more frequently observed in lakes characterized by greater size, increased depth, and reduced levels of anthropogenic land use. Furthermore, Calanoida occurrence was more probable in environments characterized by lower electrical conductivity and suspended solids concentrations. Their presence was also associated with conditions where Large mucilaginous phytoplankton (MBFG7), which includes cyanobacteria, and Large filamentous phytoplankton (MBFG3) were prevalent. An analysis of the environmental factors influencing the increase in Calanoida abundance revealed an inverse relationship between their abundance and water quality factors, including nutrient levels. This trend was observed consistently across all genera. Additionally, Calanoida were observed to maintain a high abundance in environments where the presence of the Large mucilaginous phytoplankton group (MBFG7) was relatively high. In contrast, Cyclopoida exhibited varying occurrence characteristics by genus in response to different water quality factors. Based on these results, we suggest that Calanoida, commonly used as an indicator of mesotrophic conditions, can also serve as a valuable indicator for evaluating the functionality of the food web. While Calanoida struggle to inhabit environments characterized by degraded water quality, they demonstrate the ability to adapt and persist in environments containing large, mucilaginous, or filamentous phytoplankton species that are typically challenging for other zooplankton to graze.

Endeavoring to engage in cooperative fisheries research in a contentious socio-political climate

Abstract Cooperative Fisheries Research (CFR) aims to incorporate different types of knowledge into fisheries science through the convergence of diverse perspectives, skills, and expertise. CFR can facilitate knowledge co-production and the salience, credibility, and legitimacy of science, yet it can be difficult to operationalize. In Maine’s American lobster fishery, where CFR is a hallmark of the fishery, pressure to implement conservation measures to protect North Atlantic right whales, one of the world’s most endangered large whale species, poses a major challenge for harvesters. Endeavoring to follow best practices associated with CFR, our research team set out to work with state management and fishing industry partners to evaluate the socioeconomic impacts of new whale conservation regulations on the fishery. We co-defined relevant and actionable research questions and designed a sampling approach that included multiple efforts to contact industry participants. Although the process we engaged in had some of the key ingredients for success, ultimately participation was too low to achieve our research aims. We use this paper to discuss our failure and draw on the theory of scalar politics from critical geography to reflect on challenges we encountered, including how the contentious socio-political backdrop within which the initiative transpired impacted our research.

Habitat association and demographic rates for large tree species: implications for native tree species used in forestry

Exotic tree species, though widely used in forestry and restoration projects, pose great threats to local ecosystems. They need to be replaced with native species from natural forests. We hypothesized that natural forests contain large, fast-growing, dominant native tree species that are suitable for specific topographic conditions in forestry. We tested this hypothesis using data from a 50-ha forest dynamics plot in subtropical China. We classified the plot into the ridge, slope, and valley habitats and found that 34/87 species had significant associations with at least one topographic habitat. There were 90 tree species with a maximum diameter ≥ 30 cm, and their abundances varied widely in all habitat types. In all habitat types, for most species, rate of biomass gain due to recruitment was < 1% of its original biomass, and rate of biomass gain due to tree growth was between 1 and 5% of its original biomass. For most species, biomass loss due to tree mortality was not significantly different than biomass gain due to recruitment, but the resulting net biomass increment rates did not significantly differ from zero. The time required to reach a diameter of 30 cm from 1 cm diameter for Altingia chinensis in the slope habitat, for Quercus chungii and Morella rubra in the ridge habitat and for Castanopsis carlesii in all habitats could be as short as 30 years in our simulations based on actual distributions of tree growth observed in the forest. Principal component analyses of maximum diameter, abundance and net biomass increment rates suggested several species were worthy of further tests for use in forestry. Our study provides an example for screening native tree species from natural forests for forestry. Because native tree species are better for local ecosystems, our study will also contribute to biodiversity conservation in plantations.

Multimodal signalling in manakins: lack of correlated evolution between acoustic, visual and behavioural traits

Sexual traits, such as visual adornments, sound‐based cues and courtship dances, are frequently displayed in combination as multimodal signals. Some hypotheses propose that different signals trade‐off with each other, potentially due to resource limitations (‘trade‐off’ or transfer hypothesis) or that these develop simultaneously to enhance communication effectiveness (‘joint evolution’ hypothesis). Alternatively, multiple cues may evolve independently to serve distinct functions or convey different information (‘multiple messages’ hypothesis). Here, we explored the interdependence between different signal modalities in manakins (Pipridae), which are known for great interspecific diversity in the degree of elaboration in courtship dance, song and plumage coloration. We also used comparative methods to explore the mode of evolution and the degree of conservatism of these signals. We found that song, plumage coloration and courtship dance evolved independently as there was no correlation between these traits. Song evolution in manakins was attracted to a single optimum and exhibited a weak phylogenetic signal in comparison with those of colour and behavioural diversity. The high support found for the speciational and κ models when analysing the multivariate estimates of trait variability suggests that these signals (especially colour and behaviour attributes) may have evolved in a punctuated manner, with large evolutionary changes at speciation events and minimal subsequent changes along the branches. Our results show that song, colour and dance diversity are each associated (or marginally associated) with different ecological factors, indicating that sexual signals in manakins might convey different information and/or respond to different selection pressures. Larger species and those with lower dispersal capacity tend to exhibit higher colour richness, which in turn differed among lek categories, being higher in species with ‘classic’ leks and lower in non‐lekking species. Overall, the present study supports the idea that correlation between signal modalities does not constitute a widespread pattern in songbirds.

Livestock predation patterns by gray wolves and persian leopards in Iran

Large carnivore species frequently predate and consume wild or domestic prey, which is referred to as food-related predation. Large carnivores can also hunt and kill prey exceeding their immediate needs (i.e., they do not consume prey), which is referred to as surplus predation. We used 173 records of livestock predations by gray wolves (Canis lupus; n = 133) and Persian leopards (Panthera pardus tulliana; n = 40) reported by governmental organizations of Iran during 2009–2019 to investigate food-related and surplus predation incidents of livestock. We found that for wolves, the number of reported surplus predation incidents was greater than that of food-related predation incidents during all 4 seasons (spring through winter), whereas for leopards, the number of food-related and surplus predation incidents were similar in all seasons. The number of livestock killed per surplus predation incident was greater for wolves than for leopards and that surplus predations by both species occurred more frequently within corrals than on free-range pastures. As corrals in most villages across Iran are poorly constructed and largely accessible to predators, we recommend that livestock owners enhance corral construction, use well-trained dogs during day and particularly at night, employ people to watch livestock at night, and use fire (e.g., torches) during night to scare carnivores. These strategies can mitigate predation incidents and corresponding economic losses, resulting in fewer losses of livestock, wolves, and leopards, as these two carnivore species are mainly killed by humans due to livestock predations across Iran.

The Australian Museum and Friends of Lord Howe survey of large Coleoptera on Lord Howe Island, August 2022

A survey of large beetles, one centimetre or more in length, on Lord Howe Island, was conducted in August 2022 and the results are discussed. In total, 32 large species were found. This was the first survey made at least one beetle generation after eradication of the rodents in 2019, and there was some evidence of recovery, in particular of the large flightless endemic cerambycid, Xylotoles wollastoni (White, 1856), but also of a leaf beetle, Dematochroma picea (Baly, 1864) and an exotic pest of lawns, Heteronychus arator (Fabricius, 1775). There was also evidence of recovery of Carabidae species after the prolonged dry years of 2016 to 2019.

Use of presence vs absence of symphyseal teeth in jaws for the forensic analysis of bites by large traumatogenic shark species.

Identifying the species of shark responsible for a bite on humans is both complex and important for understanding and managing the shark risk. Depending on the species, tiny teeth may or may not be present in the symphyseal space at the junction of the upper and lower half-jaws. In the case of bites, these tiny teeth (if present) often leave specific marks that may enable species to be quickly and reliably distinguished. We first present the anatomo-morphological characteristics of the jaws of the three most traumatogenic species for humans which are the white, tiger, and bull sharks. The white shark has no symphyseal teeth, while the tiger and bull sharks do. On the basis of three confirmed real case studies involving those species, we then show that for the white shark, the wide symphyseal space between the first two teeth of each jaw usually leads to wounds including the presence of (quite) large flesh flaps, without any tooth imprint. Conversely, wounds following bites made by the tiger and bull sharks will generally leave characteristic small imprints of symphyseal teeth, especially in the case of incomplete or superficial bites. Although not systematic, this diagnostic approach provides fast, reliable, and clean results. The discrimination between two species with symphyseal teeth can then be made on the basis of complementary anatomic information such as jaw curvature and details linked to the anatomy of the teeth themselves, as well as the ecological context.

Development and evaluation of a sulfate precipitation method for separating key flocculated-species from titanium-based flocculant

Key flocculated-species is the pivotal factor influencing the effectiveness of flocculants, which in turn directly determines the performance of mainstream wastewater treatment processes. Recovery of titanium-coagulated sludge and high-efficiency of titanium-coagulation have made titanium-coagulants an attractive hot point. However, the separation of key titanium-based flocculated-species remains a critical bottleneck limiting the advancement of titanium-based flocculant chemistry in water treatment. This study developed an efficient method for separating the key flocculated-species, named the sulfate precipitation method, which enables the effective purification of the key titanium-based flocculated-species. The electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) results demonstrated the successful separation of medium and large titanium-hydrolyzed-species. Ti-Ferron synchronous analysis was employed to indicate the separation of hydrolyzed products with different degrees of polymerization, including large, medium, and small species. The distribution of [OH-]/[Ti4+] (basicity) molar ratios was verified to confirm the reorganization of hydrolysis products after the reaction, resulting in varied basicities. Zeta potential results showed that species rich in medium and large hydrolyzed products had fewer positive charges, which was likely attributed to their superior flocculation efficiency, possibly due to sweep flocculation. The inductively coupled plasma mass spectrometry (ICP-MS) indicated that sulfur was present in the separated products. It was speculated that, on the one hand, the introduction of sulfate ions might have directly participated in the re-polymerization of titanium-hydrolyzed-species, potentially resulting in sulfate-doped titanium-based hydrolysis products. On the other hand, sulfate ions might have been involved in a substitution reaction with Cl- at active sites. Co-existence of these two pathways was deemed highly probable. The removal efficiency of organic matter was improved by approximately 20%, possibly owing to the rough surface (Ra = 16.2 nm). Additionally, larger flocs were generated, significantly shortening the sedimentation time in practical applications. This research presents a strategy for isolating key Ti-based flocculated species and establishes a base for their practical application.

Changes in equine strongylid communities after two decades of annual anthelmintic treatments at the farm level

The aim of this study was to assess the changes in strongylid communities of domestic horses after two decades of regular anthelmintic treatments; the changes in prevalence and relative abundance of individual strongylid species and their contribution to the observed alterations were estimated. The study was conducted in 2023; data collected in 2004 were used for comparison; 39 horses from two farms in Ukraine (22 horses in 2004 and 17 in 2023) were examined. In total, 18,999 strongylid specimens were collected by in vivo diagnostic deworming method before (in 2004, 9119 specimens) and after (in 2023, 9880 specimens) frequent application of anthelmintics. Strongylids were identified morphologically. Thirteen strongylid species were found in horses in 2023; only small strongylids (Cyathostominae) were recorded. In 2004, 21 species were found: 6 species of large strongylids (Strongylinae) and 15 of cyathostomins. Species richness (Margalef’s index) and species diversity (Shannon’s and Simpson’s indexes) decreased over two decades on both farms; the Berger-Parker dominance index for C. nassatus dramatically increased up to 74.4. The dissimilarity of strongylid communities of 2023 and 2004 was primarily connected with the disappearance of large strongylids and rare cyathostomin species after two decades of regular anthelmintic treatments. SIMPER analysis revealed that C. nassatus and C. catinatum mostly contributed to this dissimilarity. A trend of gradual transformation of the strongylid community structure from multimodal (in 2004) to bimodal (in 2023) was observed on both farms.

The Multi-Functional Use of Large Tree Cavities by Arboreal Vertebrates in a Temperate Broadleaved Forest of Eastern Europe.

Tree cavities offer protected shelters and resources for arboreal vertebrates worldwide. In general, cavities with larger openings are better accessible for predators and are avoided by smaller species for breeding, but can still be attractive for occasional use. The current study explores the diversity of functional use types and species interactions at the largest available tree cavities (entrance width ≥ 10 cm) in a temperate European forest with a low number of large cavity-breeding species. Year-round camera observations at 9 cavities (range 0.7-3.5 years) revealed 34 visiting species of birds and mammals, including non-cavity-breeding species. The top predator threatening other large-cavity users was European pine marten (Martes martes), which regularly visited each cavity year-round, on average every 0.7 months. Tawny owl (Strix aluco) was the only species successfully breeding in cavities, arguably because of its ability to defend the nests. However, other species visited cavities at an average rate of 1.5 visits per day, making predominantly short visits (less than 30 s) interpreted as exploration, searching for food, or inspecting for the presence of owls (mobbing). Making short visits and time segregation with predators was a behavioural strategy to exploit cavities for most species. These results confirm that, similarly to other keystone structures (large arboreal nests, ground burrows, etc.), large tree cavities attract a significant part of the arboreal vertebrate community and enrich their habitats. To sustain these functions in wooded ecosystems, management should provide a surplus of available cavities and diversity of their characteristics even when the apparent number of breeding species is low.

Depletion forces beyond the diluted limit

The determination of the effective interactions in many-body systems still possesses a tremendous challenge in Condensed Matter Physics. The problem mainly resides in the fact that, on the one hand, there is not a unique route to obtain the effective forces between the ”observable” constituents and, on the other hand, one typically considers that the diluted limit of those components always corresponds to the effective forces at all particle concentrations. In the particular case of colloidal dispersions, it is very important to have experimental, theoretical, and computational tools that allow us to determine, accurately and without using significant approximations, the effective interactions between colloids. In this contribution, we report on a detailed study of depletion potentials in colloidal mixtures at finite concentration, namely, binary and ternary mixtures of disks (in two dimensions or 2D) and spheres (in three dimensions or 3D). To this end, the depletion forces between the large colloidal species are determined through a recently developed scheme based on the so-called contraction of the description, which has been extended and built at the level of the bare forces, i.e., we basically consider that all particles interact through the bare potentials and the net force acting on a given particle is determined by the second’s Newton law. This scheme can be easily adapted to Molecular Dynamics simulations. To verify the physical consistency of the formalism, we explicitly show that in the diluted limit of large particles, the resulting depletion potential reproduces correctly the AO-Vrij limit. As further proof of the accuracy of the results, a comparison of the structure of the large colloids in the whole mixture with the one that results using exclusively the depletion potential is carried out. In 3D, the results are explicitly compared with the potential of mean force and those obtained with the integral equations formalism. We also report a new colloidal stability mechanism based on the use of two different species of depletant agents at low and equal concentrations. Although we highlight the fact that the depletion potential depends on the concentration of the large species, we show that this dependence can be eliminated when the colloidal dispersion is open to a reservoir of small particles, i.e., when the chemical potential of small particles is fixed. Finally, we report the effects of polydispersity on the depletion interaction between large colloids.

Recent Sociocultural Changes Reverse the Long‐Term Trend of Declining Habitat Availability for Large Wild Mammals in Europe

ABSTRACTAimPeople have strongly influenced the biosphere for millennia, but how their increasing activities have shaped wildlife distribution is incompletely understood. We examined how the distribution of European large (&gt;8 kg), wild mammals has changed in association with changing anthropogenic pressures and climate change through the Holocene.LocationEurope.MethodsWe used over 17,000 zooarchaeological records of 20 species spanning 12,000 years to develop time‐calibrated species distribution models, incorporating dynamic data on cropland extent, natural vegetation fragmentation, human population density and climate. We assessed habitat availability and potential species richness across time and within seven biogeographical regions. We also compared anthropogenic pressures at zooarchaeological record sites with present‐day habitats of remaining large mammals to evaluate recent increases in their potential for coexistence with human activities.ResultsWe found a continuous decline in potential large mammal species richness, particularly linked to changes in human population density. Most habitat loss became evident continentally after 1500 AD, but in the Atlantic and Mediterranean bioregions, habitat loss reached 20% during the Iron/Roman Ages (1000 BC–500 AD) due to increasing human population density. Climate change initially boosted species richness (+0.67 species/km2 on average) until the end of the Mesolithic but had negligible effects afterward. Today, large mammals appear to have a higher potential for coexisting with people compared to the past (e.g., herbivores today inhabit areas with a mean human population density of 95 people/km2, compared to an average of 17 people/km2 in the period 1500–2000 AD).Main ConclusionsOur study emphasizes the crucial role of anthropogenic pressures over natural climate change in determining the distribution and diversity of large mammal communities throughout history. Additionally, our results indicate that contemporary anthropogenic trends like land‐use de‐intensification and stronger conservation policies can counteract the impact of past, higher anthropogenic pressures and reverse defaunation.

Arrangements of intramembranous muscles of wings are influenced by body mass across the radiation of phyllostomid bats.

Extensive research into bat flight mechanisms has highlighted the complex functional and evolutionary dynamics of their wing structures, yet the anatomical details of certain wing muscles remain elusive. In particular, the intramembranous plagiopatagiales proprii muscles, located within the plagiopatagium-an area of the wing lacking direct joint connections-exhibit remarkable variation across bat families. These muscles, which extend anteroposteriorly in macroscopic bundles, play a crucial role in wing stiffening, modulating membrane tension, and reducing wing curvature during flight. Since larger bats tend to have higher wing loading (WL; the ratio of body mass [BMa] to wing area) and may therefore experience increased patagial curvature and resultant drag, we hypothesized that body size significantly influences the evolutionary development of the plagiopatagiales proprii muscles. This study investigates the relationship between BMa and the morphology of the plagiopatagiales proprii in New World leaf-nosed bats (Phyllostomidae), employing bivariate allometry, multivariate analysis, and comparative phylogenetic methods across 24 species from eight phyllostomid subfamilies. Our findings reveal a significant phylogenetic signal in muscle architecture, along with positive evolutionary allometry in muscle area. This suggests an adaptive increase in muscle size in larger species, likely to counterbalance the increased WL, reduce wing curvature, and minimize drag. This research enhances our understanding of the functional and adaptive morphological evolution of intramembranous wing muscles in phyllostomid bats, underscoring their evolutionary significance.

Self-stratification and phase separation in drying binary colloidal films

HypothesisFilms that develop compositional heterogeneity during drying offer a promising approach for achieving tailored functionalities. These functionalities can be realized by strategically directing different components during the drying process. One approach to achieve this is through spontaneous size segregation of colloidal particles. Two variants thereof have previously been observed in binary suspensions: layer formation (self-stratification) due to kinetically driven concentration gradients, and micro-domain formation (phase separation) due to thermodynamic depletion interactions between the small and large species. Surprisingly, in the context of binary colloidal films, these phenomena have never been investigated concurrently during evaporation. ExperimentsWe show how we can achieve both self-stratification and domain formation in a single step. Using real-time 3D confocal fluorescence microscopy, we quantitatively unravel the effects of various parameters on the emergence of compositional heterogeneity. FindingsWe reveal that beyond a certain size ratio, micro-phase separation becomes a prominent mechanism dictating the final morphology. The initial volume fraction minimally affects the final domain size but significantly impacts self-stratification. Reducing the evaporation rate increases the domain size while minimizing stratification. Finally, reducing the colloidal electrostatic interaction by a small increase in salt concentration enhances phase separation yet reverses stratification. These findings unveil a strategy for harnessing two distinct size segregation mechanisms in a single film, forming a foundation for customizable self-partitioning coatings.

Multivariate analysis and risk assessment associated with the consumption of carnivorous fish obtained from southwest Caspian Sea

Potentially toxic elements such as Cd or Pb are serious pollutants in aquatic ecosystems, accumulating in fish and posing risks to humans. Our study analyzed 10 such elements in the muscle tissue of eight carnivorous fish species from the Caspian Sea. The differences between species were minor. However, higher levels of mercury were found in larger species. The concentrations of cadmium and lead determined were high, which led to the risk analysis giving a concerning result for children. Inorganic arsenic posed an acceptable cancer risk. Overall, our findings underscore the need for constant monitoring of the area to safeguard both aquatic ecosystems and human health.

The hearts of large mammals generate higher pressures, are less efficient and use more energy than those of small mammals.

A prevailing assumption in the cardiovascular field is that the metabolic rate of the heart is a constant proportion of a mammal's whole-body aerobic metabolic rate. In this Commentary, we assemble previously published cardiovascular, metabolic and body mass data from matched terrestrial mammalian species, at rest and during heavy exercise, and reveal scaling relationships that challenge this assumption. Our analyses indicate that the fractional metabolic cost of systemic perfusion compared with whole-body metabolic rate increases significantly with body size among resting mammals, from ∼2.5% in a mouse to ∼10% in an elephant. We propose that two significant body size-dependent effects contribute to this conclusion; namely, that larger species generate higher mean systemic arterial blood pressure and that their myocardium operates with lower external mechanical efficiencies compared with those of smaller species. We discuss potential physiological and mechanical explanations, including the additional energy needed to support the arterial blood column above the heart in larger species, especially those with long necks, as well as the possible sources of greater internal energy losses from the heart of larger species. Thus, we present an updated view of how increasing blood pressure and decreasing efficiency of the myocardium result in an increasing fractional metabolic cost of perfusion as body size increases among resting mammals.