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The cost of reproduction is the core driver of life history evolution in animals. This paper demonstrates that the cumulative distance moved and the duration of movement of sexually immature abalones, Haliotis discus hannai, kept in various male and female groups, were significantly higher than those of sexually mature individuals, except when kept in mixed cultures of mature males and females. After mixed‐culture, sexually mature males moved significantly further and for a longer duration than mature female abalones, and even more so than mature male abalones of any other group. Examination of the LC‐MS metabolomics of mature males cultured with sexually mature females (AM) and those cultured with sexually immature females (JM) showed that cyclic adenosine monophosphate (cAMP) acted as a differential metabolic biomarker. After 24‐h uninterrupted sampling, the concentration of 5‐HT and the expression levels of the 5‐HT2 and 5‐HT6 receptors in AM were significantly higher than those in JM. After further injection of 5‐HT2 and 5‐HT6 receptor antagonists, the concentrations of cAMP and PKA rose again, but the cumulative movement duration and distance of male abalones decreased significantly, showing that 5‐HT was involved in the regulation of movement behavior of male abalones through the 5‐HT2 and 5‐HT6 receptor‐activated cAMP‐PKA pathways. The results demonstrated a significant increase in the movement endurance of mature male abalones cultured with mature females, providing a theoretical basis for understanding the adaptive life history strategies of abalones and suggesting ways to protect diverse benthic resources for abalones during the reproductive stage. [ABSTRACT FROM AUTHOR]

Metallic phase (1T) MoS2 has been regarded as an ideal catalytic material for the hydrogen evolution reaction (HER) due to its high active site density and favorable electrical conductivity. However, the preparation of 1T-phase MoS2 samples requires tough reaction conditions and 1T-MoS2 has poor stability under alkaline conditions. In this work, 1T-MoS2/NiS heterostructure catalysts grown in situ on carbon cloth were prepared by a simple one-step hydrothermal method. The obtained MoS2/NiS/CC combines the advantages of high active site density and a self-supporting structure, achieving stable 77% metal phase (1T) MoS2. The combination of NiS and 1T-MoS2 enhances the intrinsic activity of MoS2 while the electrical conductivity is improved. These advantages enable the 1T-MoS2/NiS/CC electrocatalyst to have a low overpotential of 89 mV (@10 mA cm−2) and a small Tafel slope of 75 mV dec−1 under alkaline conditions and provide a synthetic strategy of stable 1T-MoS2-based electrocatalysts for the HER by a heterogeneous structure. [ABSTRACT FROM AUTHOR]

In order to reduce the errors caused by the idealization of the conventional analytical model in the transient planar source (TPS) method, a finite element model that more closely represents the actual heat transfer process was constructed. The average error of the established model was controlled at below 1%, which was a significantly better result than for the analytical model, which had an average error of about 5%. Based on probabilistic optimization and heuristic optimization algorithms, an optimization model of the inverse heat transfer problem with partial thermal conductivity differential equation constraints was constructed. A Bayesian optimization algorithm with an adaptive initial population (BOAAIP) was proposed by analyzing the influencing factors of the Bayesian optimization algorithm upon inversion. The improved Bayesian optimization algorithm is not affected by the range and individuals of the initial population, and thus has better adaptability and stability. To further verify its superiority, the Bayesian optimization algorithm was compared with the genetic algorithm. The results show that the inversion accuracy of the two algorithms is around 3% when the thermal conductivity of the material is below 100 Wm − 1 K − 1 , and the calculation speed of the improved Bayesian optimization algorithm is three to four times faster than that of the genetic algorithm. [ABSTRACT FROM AUTHOR]

Pinch analysis is vital in optimizing heat exchanger networks (HENs). Targeting methods are used when determining cost effectiveness with pinch analysis. However, the existing targeting methods for the capital cost of HEN are not suitable for wide application scenarios. Therefore, we developed a high-accuracy general capital-cost-targeting method. It is built on a final structure that was evolved from the spaghetti structure of HEN through four loop elimination stages. This structure helps to reduce the prediction deviation of the method. To achieve high adaptability while establishing this method, we considered the different heat exchanger cost categories, different cost laws for one stream pair, and area limitations of heat exchangers that may be encountered in practice. In addition, allowing streams to use individual temperature difference contributions enhances the method's predictive capacity. The potential defects of the method found in numerical experiments and case studies were corrected with improvement measures. As a result, the accuracy and stability of the targeting method were further enhanced, with absolute target deviations generally within 10% and often within 5%. This study provides a benchmark for the optimal capital cost of HEN, allowing for a better economic effect when applying pinch analysis. [ABSTRACT FROM AUTHOR]

Settlement and metamorphosis is the key stage during which Haliotis discus hannai larvae change from planktonic to benthic life. Larvae tend to be highly sensitive to changes in the external environment, which can result in increased mortality. In the aquaculture industry, increasing the metamorphosis rate of larvae is considered to be a critical factor for increasing yield. In this study, we modified a recirculating aquaculture system (RAS) for dense rearing of abalone larvae. We set up five density groups (1, 5, 10, 20 and 40 ind/ml) and compared the effects of traditional aquaculture (TA) and the RAS on the hatching success rate, metamorphosis rate and the expression levels of metamorphosis‐related genes. At stocking densities of 1, 5 and 10 ind/ml, the survival rate, metamorphosis rate and expression levels of MIRP, α2ADR and DopR2 in both culture modes were significantly higher than those in the 20 and 40 ind/ml densities (p < 0.05). The metamorphosis rate and survival rate of larvae in the RAS groups were significantly higher than those in the TA groups (p < 0.05). Under TA at the 40 ind/ml stocking density, the dissolved oxygen concentration in the water declined and the TAN concentration significantly increased (p < 0.05). As the stocking density increased, the size of metamorphosed larvae under each mode tended to increase in both culture modes. In particular, when the density was highest, the time required for metamorphosis was significantly extended (p < 0.05). Based these results, use of the RAS with stocking density of 10 ind/ml would maintain a stable aquaculture water environment, prevent fertilized eggs from hatching or becoming densely aggregated before larval metamorphosis, and significantly increase the stocking density per unit water. These results provide an important reference for scaling up reproduction of larval abalone and further developing the culture mode for this economically important shellfish. [ABSTRACT FROM AUTHOR]

The light environments of natural water sources have specific characteristics. For the majority of aquatic organisms, vision is crucial for predation, hiding from predators, communicating information, and reproduction. Electroretinography (ERG) is a diagnostic method used for assessing visual function. An electroretinogram records the comprehensive potential response of retinal cells under light stimuli and divides it into several components. Unique wave components are derived from different retinal cells, thus retinal function can be determined by analyzing these components. This review provides an overview of the milestones of ERG technology, describing how ERG is used to study visual sensitivity (e.g., spectral sensitivity, luminous sensitivity, and temporal resolution) of fish, crustaceans, mollusks, and other aquatic organisms (seals, sea lions, sea turtles, horseshoe crabs, and jellyfish). In addition, it describes the correlations between visual sensitivity and habitat, the variation of visual sensitivity as a function of individual growth, and the diel cycle changes of visual sensitivity. Efforts to identify the visual sensitivity of different aquatic organisms are vital to understanding the environmental plasticity of biological evolution and for directing aquaculture, marine fishery, and ecosystem management. [ABSTRACT FROM AUTHOR]

Primitive cnidarians are crucial for elucidating the early evolution of metazoan body plans and life histories in the late Neoproterozoic and Palaeozoic. The highest complexity of both evolutionary aspects within cnidarians is found in extant hydrozoans. Many colonial hydrozoans coated with chitinous exoskeletons have the potential to form fossils; however, only a few fossils possibly representing hydroids have been reported, which still require scrutiny. Here, we present an exceptionally well-preserved hydroid found in the Upper Cambrian Fengshan Formation in northern China. It was originally interpreted as a problematic graptolite with an uncertain systematic position. Based on three characteristic morphological traits shared with extant hydroids (with paired hydrothecae, regular hydrocaulus internodes and special intrathecal origin pattern of hydrocladium), we propose this fossil hydroid as a new genus, Palaeodiphasia gen. nov., affiliated with the advanced monophyletic hydrozoan clade Macrocolonia typically showing loss of the medusa stage. More Macrocolonia fossils reviewed here indicate that this life strategy of medusa loss has been achieved already as early as the Middle Devonian. The early stratigraphical appearance of such advanced hydroid contrasts with previous molecular hypotheses regarding the timing of medusozoan evolution, and may be indicative for understanding the Ediacaran cnidarian radiation. [ABSTRACT FROM AUTHOR]

Biological systematics provides taxonomic information and expertise for biogeography and biological invasion research and management. However, the systematic classification of most taxa, including some alien and invasive species, relies only on morphology. This applies for example to Sertularella tongensis Stechow, 1919 (Cnidaria: Sertulariidae), an alien hydrozoan recently reported in the Mediterranean. Its genus affiliation is still unclear and controversial. Historically, it has been assigned to several existing genera. However, molecular data (COI, 16S, 18S, 28S) provided here do not support these previous assignments. Instead, integrative analyses combining morphological and molecular data support reassigning this species to a new genus, Bicaularia gen. nov. A biogeographic review revealed that this species is widely distributed in the mid- and low-latitude waters of the Indo-Pacific region, and is spreading to some tropical and temperate regions including the Mediterranean and Caribbean Seas, as well as Korea and Japan. This expansion may be attributable to human activity such as shipping through the Suez and the Panama Canals. However, the new record attached to a floating Sargassum algal fragment in the surface water of the open Pacific, might suggest a neglected cryptic spread pathway with the assistance of floating biological organisms. Our findings shed light on the complexity of the phylogeny and spread pathway of the investigated hydrozoan species. We regard the fine systematics as the first step towards future global sampling for molecular studies aiming to elucidate the origins and pathways for alien and invasive species. : pub: 45AB0849-1E3B-477FB643-1B3B4603C1FF [ABSTRACT FROM AUTHOR]

Molecular phylogenetics provides objective references for zoological systematics which sometimes are inconsistent with morphological data. This applies particularly for some primitive phyla such as Cnidaria. The marine hydrozoan Symplectoscyphus turgidus (Sertularellidae) is a recent questionable case reported to occupy an unexpected phylogenetic position and suggested to belong to a new genus. However, its position, based on a single Californian specimen, seemed doubtful. Here we contributed 16S, 18S and 28S rRNA data of another morphologically related species from the Yellow Sea, forming a monophyletic clade with the Californian sample, confirming the clade stability. Further integrative analyses support describing this clade as the new genus Xingyurella , gen. nov., and lead to a taxonomic revision of species characterised by three hydrothecal marginal teeth and strong gonothecal spines. This resulted in a new species and three new combinations: Xingyurella xingyuarum , sp. nov., X. gotoi , comb. nov., X. pedrensis , comb. nov. and X. turgida , comb. nov. Future investigations are required to understand the evolution and speciation involved in the transoceanic distribution pattern of Xingyurella. The approach used herein for dealing with non-monophyletic conditions may be indicative for further studies by integrating trophosome and gonosome traits for Sertularellidae and other hydrozoans. http://zoobank.org/urn:lsid:zoobank.org:pub:E99F8777-8E31-4C4B-A065-71C71371EEBC. Molecular phylogenetics sometimes is inconsistent with morphological data, notably within the phylum Cnidaria. An integrative approach to a case of incongruence in hydrozoans results in improved systematics, with the designation of a new genus with divergent origin, endemic to the eastern and western coasts of the North Pacific Ocean. This suggests that incongruence in molecular and morphological inferences may be of great systematic significance. [ABSTRACT FROM AUTHOR]