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Mathematical model plays a significant role in describing the mutual interaction of various chemical compositions in chemistry. In this present work, we formulate a new plankton–oxygen dynamical model owning delay. By virtue of fixed point theorem, inequality techniques and construction of function, we set up the conditions on existence and uniqueness, non-negativeness and boundedness of the solution to the formulated plankton–oxygen model. Taking advantage of bifurcation and stability theory of delayed differential equation, we explore the existence of bifurcation and stability for the plankton–oxygen model and set up a novel delay-independent criterion ensuring the existence of bifurcation and stability of the model. Making use of two different extended hybrid controllers, we can successfully control the time of emergence of bifurcation and stability domain of this model. The impact of delay on bifurcation and stability of the model is explored. Software experiment results are provided to sustain the acquired key outcomes. The gained conclusions of this work are perfectly novel and possess immense theoretical significance in adjusting and balancing the concentrations of disparate chemical compositions. [ABSTRACT FROM AUTHOR]

Several factors significantly contribute to the onset of infectious diseases, including direct and indirect transmissions and their respective impacts on incubation periods. The intricate interplay of these factors within social networks remains a puzzle yet to be unraveled. In this study, we conduct a stability analysis within a network-organized SIR model incorporating dual delays to explore the influence of direct and indirect incubation periods on disease spread. Additionally, we investigate how compound networks affect the critical incubation period. Our findings reveal several vital insights. First, by examining crossing curves and the dispersion equation, we establish the conditions for Turing instability and delineate the stable regions associated with dual delays. Second, we ascertain that the critical incubation value exhibits an inverse relationship with a network's eigenvalues, indicating that the Laplacian matrix does not solely dictate periodic behavior in the context of delays. Furthermore, our study elucidates the impact of delays and networks on pattern formation, revealing distinct pattern types across different regions. Specifically, our observations suggest that effectively curtailing the spread of infectious diseases during an outbreak is more achievable when the incubation period for indirect contact is shorter and for direct contact is longer. Namely, our network framework enables regulation of the optimal combination of (τ 1 , τ 2) to mitigate the risk of infectious diseases. In summary, our results offer valuable theoretical insights that can inform strategies for preventing and managing infectious diseases. [ABSTRACT FROM AUTHOR]

In this current study, novel fractional neural networks owning delay are formulated. Using Lipschitz condition, we demonstrate that the solution of the formulated fractional delayed neural networks exists and is unique. Applying a reasonable function, we handle the boundedness issue of solution to the formulated fractional delayed neural networks. Exploiting the stability criterion and bifurcation viewpoint of the fractional order delayed dynamical system, we explore the stability and bifurcation phenomenon of the established fractional delayed neural networks. Taking advantage of an adequate hybrid controller, we have efficaciously dominated the stability domain and the time of generation of bifurcation of the formulated fractional delayed neural networks. Ultimately, computer simulation graphs are provided to sustain our acquired outcomes. The acquired theoretical outcomes of this study possess considerable realistic meaning in regulating and controlling neural networks. [ABSTRACT FROM AUTHOR]

Purpose: In order to analyze the effects of rotor hybrid eccentricity and bearing clearance on the internal excitation force and dynamic characteristics of the rotor bearing system of a permanent magnet motorized spindle, a nonlinear dynamic and lumped parameter model of the rotor bearing system is developed in this paper. Methods: Firstly, the model is solved based on the variable-step Runge-Kutta method. Secondly, the effect of internal parameter variations on the timefrequency characteristics of the system is analyzed by the Fourier transform. Finally, based on the bifurcation trajectory of the system speed and the Poincaré map, the dynamic characteristics evolution of the rotor-bearing system in the full speed range is analyzed. Results: The results show that the variation of rotor mixing eccentricity and bearing clearance leads to a complex coupling of nonlinear excitation forces within the system, which in turn causes the system to exhibit rich dynamic behavior. Conclusion: Changes in the initial static eccentricity of the rotor will lead to changes in the frequency characteristics of the unbalanced magnetic pull, and increasing the eccentricity of the rotor mass will increase the amplitude of the system response, which is more likely to lead to resonance due to changes in the coupling state of the excitation forces within the system due to changes in bearing clearance. When the rotor eccentricity and bearing clearance are controlled in a small range, the system has better stability in the high-speed range [ABSTRACT FROM AUTHOR]

In this research, a kind of BAM neural networks containing three nonidentical time delays are explored. Exploiting fixed point knowledge, we examine that the solution to the concerned BAM neural network models exists and is unique. Exploiting a apposite function, we check that the solution to the concerned BAM neural network models is bounded. In line with different delay cases, we systematically analyze the characteristic equations of the concerned BAM neural network models. A set of innovative bifurcation criteria of the concerned BAM neural network models under the six delay situations are acquired. The impact of delay is adequately revealed under different delay cases. The research indicates that delay plays a pivotal role in dominating stability domain and the time that Hopf bifurcation arises. of the concerned BAM neural networks. In order to sustain the theoretical assertions, we present the corresponding software simulation plots. The acquired conclusion of this research are completely novel and has momentous theoretical values in dominating and devising networks. [ABSTRACT FROM AUTHOR]

Merocyanine dyes are of great interest amongst researchers due to their nonlinear optical (NLO) properties and solvatochromism. Molecular structure of these dyes constitutes conjugated pathway between the donor and acceptor substituents, with lowest energy transition of π – π * character. To rationalize the design of these dyes and deduce structure-property relationship, it is eminent to unravel the excited state dynamics in these complex molecular structures in different solvents. Here we have studied excited state dynamics of a merocyanine dye known as HB194, which has shown commendable efficiency in small molecule based bulk heterojuction solar cells. We have employed femtosecond transient absorption in combination with the quantum chemistry calculations to unravel the solvent dependent charge transfer dynamics of HB194. The excited state decays of the HB194 in different solvents show multi-exponential components. The analysis of the time-resolved data reveals that the polar solvents induce conformationally relaxed intramolecular charge transfer state. In non-polar solvent cyclohexane, only solvent-stabilized ICT state is observed. Additionally, we observe an anomalously red-shifted emission in ethylene glycol centred at ∼ 750 nm. Our computational calculations suggest the presence of molecular dimers resulting into observed red-shifted emission band. Our work therefore underscores the importance of gathering molecular-level insight into the system-bath interactions for designing next generation merocynanine-based solvatochromic dyes. [ABSTRACT FROM AUTHOR]

Considering that time delay (delay) is a common phenomenon in biological systems, reaction-diffusion equations with delay are widely used to study the dynamic mechanism of those systems, in which delay can induce the loss of stability and degradation of performance. In this paper, taking into account the inhomogeneous distribution of species in space and this can be considered as a random network, the pattern dynamics of a prey-predator network system with diffusion and delay are investigated. The effect of delay and diffusion on the network system is obtained by linear stability analysis, including the stability and Hopf bifurcation as well as Turing pattern. Our results show that the stability of the system changes with the value of delay. Moreover, we obtain Turing pattern related to the network connection probability and diffusion. Finally, the numerical simulation verifies our results. [ABSTRACT FROM AUTHOR]

Higher-order networks reveal intricate structural connections within neural brain models by exposing relationships between multiple nodes. Within human brain networks, information transmission among neurons invariably incurs a time delay, resulting in abnormal discharge of membrane potential. In this study, we analyze correlation visualizations of the Laplacian matrix derived from both general networks and higher-order networks, highlighting eigenvector distributions. The presence of time delay significantly influences the dynamical behavior of the system. Therefore, we examine the phase diagram, identifying firing patterns such as fast-spiking and mixed-mode oscillations. Ultimately, we demonstrate that both time delay and diffusion can alter the dynamical behavior of the FitzHugh–Nagumo model. Notably, within higher-order networks, the phenomenon of Turing instability becomes more pronounced, offering an analogous framework for studying associated diseases. This instability emerges as neuronal states approach abnormal levels, leading to the onset of related diseases. Numerical simulation and data also verify these results. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the modified two dimensional model which can explain somite patterning in embryos. It is suitable for exploring a design space of somitogenesis and can explain aspects of somitogenesis that previous models cannot. Here, we mainly studied the non-diffusing case. We have used the Hopf bifurcation theorem, the Center manifold theorem and Runge-Kutta method in our investigation. First, we investigate its dynamical behaviors and put forward a sufficient condition for the oscillation of the small network. Then, we give the mathematical simulation based on the Runge-Kutta method. In the process of solving ordinary differential equations, the four order Runge-Kutta method has the advantages of high accuracy, convergence and stability (under certain conditions), which can change the step size and do not need to calculate higher order derivatives. Therefore, it has become the most commonly used numerical solution. At the same time, we get the sufficient condition in which the bistable state of the system exists and give the numerical simulation. Because somitogenesis occupies an important position in the process of biological development, and as a pattern process can be used to study pattern formation and many aspects of embryogenesis. So our study have a great help for embryonic development, gene expression, cell differentiation. In addition, it is beneficial to study the clone animal variation problem of spinal bone number and is of great help to the treatment and prevention of defects of human spine disease. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of pinning cluster synchronization for colored community networks via adaptive aperiodically intermittent control. Firstly, a general colored community network model is proposed, where the isolated nodes can interact through different kinds of connections in different communities and the interactions between different pair of communities can also be different, and moreover, the nodes in different communities can have different state dimensions. Then, an adaptive aperiodically intermittent control strategy combined with pinning scheme is developed to realize cluster synchronization of such colored community network. By introducing a novel piecewise continuous auxiliary function, some globally exponential cluster synchronization criteria are rigorously derived according to Lyapunov stability theory and piecewise analysis approach. Based on the derived criteria, a guideline to illustrate which nodes in each community should be preferentially pinned is given. It is noted that the adaptive intermittent pinning control is aperiodic, in which both control width and control period are allowed to be variable. Finally, a numerical example is provided to show the effectiveness of the theoretical results obtained. [ABSTRACT FROM AUTHOR]

We demonstrate a simple method for the determination of the magnetic field in an ion trap using laser-cooled Be ions. The method is not based on magnetic resonance and thus does not require delivering radiofrequency (RF) radiation to the trap. Instead, stimulated Raman spectroscopy is used, and only an easily generated optical sideband of the laser cooling wave is required. The d.c. magnetic vector, averaged over the Be ion ensemble, is determined. Furthermore, the field strength can be minimized and an upper limit for the field gradient can be determined. The resolution of the method is 0.04 G at present. The relevance for precision rovibrational spectroscopy of molecular hydrogen ions is briefly discussed. [ABSTRACT FROM AUTHOR]

In this paper, we consider the process of pattern formation induced by nonlinear diffusion in the gene network with cross-diffusion. We present a theoretical analysis of the pattern formation and show how cross-diffusion is able to destabilize the uniform equilibrium, being therefore liable for the emergence of spatial patterns. Through the linear stability analysis, we analytically derive a set of sufficient conditions which guarantee that the system generates turing instability, indicating that the competition and cross-diffusion between protein and mir-17-92 can lead to the turing pattern formation. Furthermore, we also obtain the Turing regions in which Turing patterns are generated. [ABSTRACT FROM AUTHOR]

Black band disease (BBD), characterized by the Cyanobacterial dominated pathogenic consortium, is thought to play a key role in the global decline of the coral reef ecosystems. The present paper originally documents a case of BBD from Yongxing Island (Xisha Islands, South China Sea), and further probes the reasons of this abnormal phenomenon. Prior to 2007, corals at northern reef-flat of Yongxing Isand were in healthy growth. Catastrophic coral mortality occurred between 2007 and 2008. The 16S rRNA gene sequencing and PCR amplification, with universally conserved primers, were applied to detect the contagious bacterial community of the microbial mat. The results demonstrated that six bacterial divisions constituted the clone libraries derived from the BBD mat, and that Cyanobacteria are the most diversely represented group that inhabit BBD bacterial mats, despite the fact that species in five others divisions (α-Proteobacteria, γ-Proteobacteria, Bacteroidetes, Verrucomicrobia and Actinobacteria) are also consistently diverse within the BBD mats of diseased coral. Other factors such as coral bleaching, typhoons, ocean acidification and crown-of-thorns starfish outbreaks, are not primarily responsible for the coral mortality within such a short time interval. The disaster expansion of BBD associated with Cyanobacterial blooms is a more likely mechanism impacting these coral reefs. Excessive human activity enhances the eutrophication of the marine water of the reefal region and may result in occurrence of the BBD. [ABSTRACT FROM AUTHOR]

Microbes and microbial carbonates in reef-flat and coral community dynamics and submarine geomorphologic features in reef crest and fore reef of Yongxing Island, the Xisha Islands, South China Sea, were studied by means of scuba diving, underwater investigation, and line intercept transect survey. Studies indicate a very high coral mortality with few living corals in the reef flat of Yongxing Island. Moreover, macro algae, sea grass and cyanobacteria are common in reef flat. Microbes and microbially induced carbonates occur in reef flat. Living corals grow mainly in the reef crest and fore reef, but are also declined dramatically. From coast to off shore, the southeast reef flat of Yongxing Island can be divided into beach, inner reef flat, outer reef flat, reef flat front (reef crest and fore reef), and fore-reef slope settings. Sedimentary facies include coast, reef flat, reef crest and fore reef, and fore-reef slope. Reefal carbonate sediments are composed of coral skeletons and framework, coral fragments, bioclasts, and lime mud. With the deterioration of environment and water quality, the coral communities tend to be distributed in the reef crest and fore reef with clean sea water, well circulation and moderate water energy. Reef flat is occupied mainly by the macro algae and Heliopora coerulea communities. The coverage statistics on the reef crest demonstrate that the coverage of Acropora cytherea is more than 28% and represents a dominant species with wave-resistant ecological type. Sedimentary characteristics and geomorphologic features are different between the southeast and northwest reef-flat fronts (reef crest and fore reef) of Yongxing Island. The former shows discontinuously tidal channels in outer reef flat and different dimensional and deep reef ponds in reef crest and fore reef, and the latter presents a typical spur-and-groove system. Microbes (cyanobacteria Lyngbya sp.) occur generally in the inner reef flat and reef ponds of reef crest with restricted water circulation. Widely algae growth indicates a eutrophic environment, and the common microbes on the coral surface in the reef flat and reef ponds also demonstrate eutrophication in seawater and deteriorated water quality. [ABSTRACT FROM AUTHOR]

Polychaete serpulids are globally distributed tubeworms mostly in marine environments from Late Triassic to modern time. These calcareous tubeworms could be rock-forming, reef-building, or a principal fouling organism in harbor and bays. Carbonates of the Paleogene Kalatar Formation in southwest Tarim Basin yield abundant serpulid fossils, which, together with oyster fossils, constitute the characteristic fossil assemblage of the Kalatar Formation. Other common fossils include bivalves, gastropods, ostracods, echinoderms, and bryozoans. Lithologies that yielded serpulid fossils are characterized by micritic bioclastic limestone, sandy limestone, and shelly limestone, indicating a semi-restricted to open shallow marine environment with medium to low water energy. The research data about serpulids and their fossil materials from China are relatively rare. Based on the studies of fossils taxonomy, community palaeoecology, and fossil taphonomy, this paper analyzed and studied the types, occurrence, distribution, and morphological characteristics of serpulids and their palaeoecological features in the Kalatar Formation. Two serpulid community compositions were recognized in the Kalatar Formation, including a rock-forming Ditrupa community and a cluster-growth Propomatoceros community. The Ditrupa community was distributed in coastal environment of the west Kunlun piedmont, lived on sandy hard substrates with little mud, and rarely occurred in lagoon and tidal settings. The Propomatoceros community occurred in offshore middle carbonate ramp in the piedmont of the south Tianshan Mountains and in offshore shelf in the piedmont of the west Kunlun Mountains. According to the analysis on the host-rock lithologies, preservation and symbionts, it is inferred that serpulids in the Kalatar Formation grew on the oyster shell or other hard substrate, and they did not form reefs or bioherms. [ABSTRACT FROM AUTHOR]

Modern fringing reefs are developed on the intertidal to subtidal area of Xiaodonghai bay, Sanya, Hainan Island. The reef flat extends several dozen meters toward the sea. Various ecological and sedimentary zonations can be distinguished, including, from land to sea, beachrocks, large massive corals, inner reef flat, outer reef flat, and fore-reef slope. The carbonate sediments and constituent hermatypic coral communities are different in these zones. The beachrocks are composed mainly of biological sands, including coral skeletons, algae, gastropods, bivalves, and benthic foraminifera. Quartz sands are less common in this zone. Carbonate diagenesis in beachrocks is characterized by early cementation. The fringing reef flat is progradationally developed toward the sea. Large massive corals grew in the zone next to the beachrocks. These corals are large, flat-toped, and autochthonous in the production of bioclastic grains and lime mud. Large and massive coral skeletons are surrounded by coral skeletal grains, bioclasts, and lime-mud sediments. The inner reef flat consists mainly of skeletons of branching corals that are covered by bioclasts and lime mud, and living corals are mostly massive in form. Statistical analysis of coral-community dynamics shows that the outer reef flat with strong waves is the most suitable place for hermatypic corals to flourish. There, the living corals are most densely distributed. Both massive corals and branching corals (e.g., Acropora corymbosa) are exceptionally healthy in this zone. Bioclasts and lime mud are washed out due to strong wave action. Microbial carbonates generally are deposited within cavities of the beachrocks and coral skeletal cavities and on the surfaces of bioclastic grains. The latter two types, however, are more common. Ecological-sedimentary zonations across the Xiaodonghai reef flat from beachrocks to outer reef flat are controlled by variations in wave strength and water energy. Microbial carbonates rarely developed on outer reef flat under strong wave action. [ABSTRACT FROM AUTHOR]

Meiji (Mischief) coral atoll, in Nansha (Spratly) Islands, South China Sea, consists of an annular reef rim surrounding a central lagoon. On the atoll rim there are either protuberant ‘motu’ (small coral patch reefs on the rim of atoll) islets or lower sandy cays that contain modern microbialite deposits on the corals in pinnacles and surrounding bottoms of the atoll. Microbialites, including villiform, hairy, and thin spine growth forms, as well as gelatinous masses, mats and encrustation, developed on coral colonies and atoll rim sediments between 0 and 15 m deep-water settings. The microbialites were produced by natural populations of filamentous cyanobacteria and grew on (1) bulbous corals together with Acropora sp., (2) on massive colonies of Galaxea fascicularis, (3) on dead Montipora digitata, and (4) on dead Acropora teres, some hairy microbialite growing around broken coral branches. This study demonstrates that microbial carbonates are developed in coral reefs of South China Sea and indicates that microbial processes may be important in the construction of modern reef systems. The results have significance in the determination of nature and composition in microorganisms implied in the formation ancient microbialites, and permit evaluation of the importance of microbial deposits in modern coral reefs and of ‘microbialites’ in biogeochemical cycles of modern coral reef systems. The results also provide evidence of modern analogues for ancient microbialites in shallow-water settings, and combine with sedimentological studies of ancient microbialites to understand their controls. [ABSTRACT FROM AUTHOR]

Two research methods, geomicrobiology and carbonate sedimentology, were adopted to study the microbial carbonates in the beachrocks, Shuiweiling, Luhuitou, Sanya City, Hainan Island. The results indicate that microbial carbonates occur in Shuiweiling beachrocks and cements related to microbial activitives are common. Microbial carbonates were mainly developed on the surfaces of coral skeletons and within the coral (fragments and shivers) skeletal cavities, and rarely grew in interspaces formed by coral and other biological detritus. The growth morphologies of microbial carbonates are various, including stromatolitic lamination, thin crusts, dome-like, and microbialites. Microbial carbonates commonly trap fine-sized bioclasts, contain tubular filaments, and show laminated growth striation. Microbial carbonates within the coral skeletal cavities are generally stromatolitic cone-shaped, with a random growth direction along the bearing of trend of cavities, showing distinct growth laminae and recognizable growth phases. It is a special growth pattern of crypt microbial carbonates. Microbial cements occur mainly in shape of needle cement, calcified filaments, microborings, and calcified framboidal spheres. The needle cement is the most common type. These microbial cements indicate that microbial activities and microbial carbonates played an important role in beachrock formation in which carbonates were dominant components and the climate of tropical ocean monsoon was influential. Such microbial carbonates and microbial cementation have not been reported here from beachrocks along the northern shorelines of the South China Sea. The results support a clear microbial origin for certain carbonate cements in beachrocks, confirm that microbial carbonates are a significant contributor to carbonate sedimentation, and widen the knowledge of beachrocks from a new field. [ABSTRACT FROM AUTHOR]

Microbial precipitation of calcium carbonate has played a major role in formation of carbonate platforms since the Archean. Also, microbial carbonates and biologically induced cement are important contributors to reef framework volume and rigidity in carbonate platform systems during times of significant environmental change including transgressive events in platform environments and the recovery interval following the major biotic crisis. The stratigraphic distribution of different types of microbial carbonates appears to vary within the sequence stratigraphic framework. Reefs and mounds within the Late Devonian carbonate platforms in Guilin, South China are formed primarily by calcimicrobes and biologically induced cement, representing the microbe-dominated and characteristic carbonate buildups within a reefal ecosystem that nearly all reef-building metazoans were absent after the Frasnian/Famennian biotic crisis. Microbial community and microbialite seem to be linked with specific palaeoenvironment and palaeoclimate, suggesting that they could be used as indicators of environmental change and biotic events. [ABSTRACT FROM AUTHOR]

To achieve a high yield of tropane alkaloids (TA) and exploit the alpine plant sustainably, an optimized protocol for induction and establishment of hairy roots culture of Prezwalskia tangutica Maxim was developed through selection of appropriate Agrobacterium strain and the explant type. The hypocotyl is more readily facile to induce the HR than the cotyledon is when infected with the three different agrobacterium strains. MUS440 has an efficiency (of up to 20%), whereas the ATCC10060 (A4) can induce HR on both types of explants with the highest frequency (33.33%), root length (21.17 ± 2.84 cm), and root number (10.83 ± 1.43) per explant than the other strains. The highest HR production resulted from using hypocotyl as explants. Independent transformed HR was able to grow vigorously and to propagate on a no-hormone 1/2MS liquid medium. The presence of pRi rolB gene in transformation of HR was confirmed by PCR amplification. In the liquid medium, the HR growth curve appeared to be “S” shaped, and ADB had increased to 4.633 g/l. Moreover, HPLC analysis showed that HR lines have an extraordinary ability to produce atropine (229.88 mg/100 g), anisodine (4.09 mg/100 g), anisodamine (12.85 mg/100 g), and scopolamine (10.69 mg/100 g), which were all more significant than the control roots. In conclusion, our study optimized the culture condition and established a feasible genetics reactor for P. tangutica green exploration and biological study in the alpine region. [ABSTRACT FROM AUTHOR]