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In this study, our primary emphasis lies in examining and exploring the decay rate of solutions of a Lord‐Shulman thermoelastic Timoshenko model with microtemperature impact. Through the application of the energy method within the Fourier space and subject to appropriate assumptions, we prove that the decay rate of the solution is of the form (1+t)−18$$ {\left(1+t\right)}^{-\frac{1}{8}} $$ in the case of absence of mechanical damping term. [ABSTRACT FROM AUTHOR]

This paper investigates the stability problem and large time behavior of solutions to the three‐dimensional magnetohydrodynamic equations with horizontal velocity dissipation and magnetic diffusion only in the x2$x_2$ direction. By applying the structure of the system, time‐weighted methods, and the method of bootstrapping argument, we prove that any perturbation near the background magnetic field (1, 0, 0) is globally stable in the Sobolev space H3(R3)$H^3(\mathbb {R}^3)$. Furthermore, explicit decay rates in H2(R3)$H^2(\mathbb {R}^3)$ are obtained. Motivated by the stability of the three‐dimensional Navier–Stokes equations with horizontal dissipation, this paper aims to understand the stability of perturbations near a magnetic background field and reveal the mechanism of how the magnetic field generates enhanced dissipation and helps stabilize the fluid. [ABSTRACT FROM AUTHOR]

Persistence of spatial analyticity is studied for solutions of the generalized Korteweg‐de Vries (KdV) equation with higher order dispersion ∂tu+(−1)j+1∂x2j+1u=∂xu2k+1,$$\begin{equation*} \partial _{t} u+(-1)^{j+1}\partial _{x}^{2j+1} u= \partial _x{\left(u^{2k+1} \right)}, \end{equation*}$$where j≥2$j\ge 2$, k≥1$k\ge 1$ are integers. For a class of analytic initial data with a fixed radius of analyticity σ0$\sigma _0$, we show that the uniform radius of spatial analyticity σ(t)$\sigma (t)$ of solutions at time t$t$ cannot decay faster than 1t$\frac{1}{\sqrt t}$ as t→∞$t\rightarrow \infty$. In particular, this improves a recent result due to Petronilho and Silva [Math. Nachr. 292 (2019), no. 9, 2032–2047] for the modified Kawahara equation (j=2$j=2$, k=1$k=1$), where they obtained a decay rate of order t−4+$ t^{-4 +}$. Our proof relies on an approximate conservation law in a modified Gevrey spaces, local smoothing, and maximal function estimates. [ABSTRACT FROM AUTHOR]

We consider the Cauchy problem of the compressible quantum Navier–Stokes–Maxwell equations with the linear damping in the isentropic case under the small perturbation of the constant equilibrium state in three dimensions. Based on the refined energy method, we establish the classical solution globally in time in Sobolev space. By the combination of the energy estimates with the interpolation between the positive Sobolev norms and the negative Sobolev norms ∥·∥Ḣ−s$\Vert \cdot \Vert _{\dot{H}^{-s}}$ with 0⩽s<3/2$0\leqslant s<3/2$ , we also obtain the algebraic decay rates of the classical solution. What is more, the Lp$L^p$–L2(1

In this paper, we consider the initial boundary value problem of the generalized pseudo‐parabolic equation containing viscoelastic terms and associated with Robin conditions. We establish first the local existence of solutions by the standard Galerkin method. Then, we prove blow‐up results for solutions when the initial energy is negative or nonnegative but small enough or positive arbitrary high initial energy, respectively. We also establish the lifespan and the blow‐up rate for the weak solution by finding the upper bound and the lower bound for the blow‐up times and the upper bound and the lower bound for the blow‐up rate. For negative energy, we introduce a new method to prove blow‐up results with a sharper estimate for the upper bound for the blow‐up times. Finally, we prove both the global existence of the solution and the general decay of the energy functions under some restrictions on the initial data. [ABSTRACT FROM AUTHOR]

Mnemiopsin 1 (Mn1) and Mnemiopsin 2 (Mn2) are photoproteins found in Mnemiopsis leidyi. We have tried to answer the question of whether the structural features of photoproteins can explain the observed activity data. According to the activity measurements data, they have the same characteristic wavelength. However, the initial intensity of Mn2 is significantly higher than that of Mn1, and decay time of Mn1 (0.92 s−1) is lower than that of Mn2 (1.46 s−1). The phylogenetic analysis demonstrates that, compared with Obelin and Aequorin from Obelia longissima and Aequorea victoria, respectively, a gene modification event may have caused the expansion of the N‐terminal side of all photoproteins from M. leidyi. An in silico study has shown that the stability of the photoprotein–substrate complex of Mn2 is higher than that of Mn1, indicating a higher affinity of the substrate for Mn2 compared with Mn1. It was revealed that the active EF‐hand loops 1 and III in Mn2 is locally more rigid compared with those in Mn1. We concluded that different stability of the photoprotein complexes leads to different initial intensity. While different patterns of the local dynamics of loops I and III may influence the decay rate. [ABSTRACT FROM AUTHOR]

This paper is concerned with the stability analysis and stabilization of periodic piecewise positive systems. By constructing a time‐scheduled copositive Lyapunov function with a time segmentation approach, an equivalent stability condition, determined via linear programming, for periodic piecewise positive systems is established. Based on the asymptotic stability condition, the spectral radius characterization of the state transition matrix is proposed. The relation between the spectral radius of the state transition matrix and the convergent rate of the system is also revealed. An iterative algorithm is developed to stabilize the system by decreasing the spectral radius of the state transition matrix. Finally, numerical examples are given to illustrate the results. [ABSTRACT FROM AUTHOR]

In this paper, we study the full parabolic attraction–repulsion Keller–Segel model with a fractional diffusion in ℝn$$ {\mathbb{R}}^n $$ for n=2$$ n=2 $$ or 3. We are more interested in the question that whether the solutions exist globally or blow up in finite time, which was studied in the classical attraction‐repulsion Keller‐Segel model by Jin and Wang (J. Differential Equations, 2016) through constructing a suitable energy functional. However, for the fractional attraction–repulsion Keller–Segel model, it is challenging to find a similar energy functional to study the existence of the solutions. In the present paper, under the condition of ξγ=χα$$ \xi \gamma =\chi \alpha $$, we introduce the Lp$$ {L}_p $$‐ Lq$$ {L}_q $$ estimates of the fractional derivative modulus of the solution to carry out the first step of the problem. Armed with a priori estimate, it is sufficient for us to obtain the global existence of the solutions by the Moser–Alikakos iterative method and finally arrive at the decay estimates of the solutions. [ABSTRACT FROM AUTHOR]

Plasmonic nanostructures offer an enticing prospect in many applications, ranging from lasing to biosensing, due to their unrivaled light concentration beyond the diffraction limit. However, this promise is substantially undercut by the intrinsically high losses in metals. Here, an experimental ultra‐high‐Q plasmon resonance with a linewidth down to 2 nm (Q‐factor ≈ 350) and a resonance intensity of 51% in an ultrasmooth gold nanogroove array is reported. Such an experimental ultranarrow resonance arises from two key factors. First, a geometrical‐induced coupling between the Fabry–Pérot and Wood's anomaly modes significantly suppresses the groove array's radiative damping. Second, an ultrasmooth gold surface fabricated by template stripping minimizes its surface scattering and grain boundary scattering. Benefiting from this ultranarrow resonance, a figure of merit (FOM) of 284 and an FOM* of 617 in refraction index (RI) sensing under normally incident detection are demonstrated, the former of which is the record FOM in all reported broad‐RI‐range plasmonic RI sensors. The array is further demonstrated as a surface thickness sensor for detecting mercaptocarboxylic acids with the surface sensitivity of 0.18 nm/CH2, which suggests that the array is a promising platform for thickness detection of surface analytes and label‐free biomedical sensing. [ABSTRACT FROM AUTHOR]

In this paper, we establish the Lp-norm (1 < p ≤ ∞) algebraic decay rate of solutions and higher-order derivative of solutions for 3D generalized Hall-MHD systemprovided that the L¹-norm of initial data is sufficiently small and the parameters α ∈ [ 5 4, 2 ],β ∈ [ 7 4, 2 ] . [ABSTRACT FROM AUTHOR]

We consider a coupled system of viscoelastic wave equation with weak, strong damping and power nonlinearity. For a single viscoelastic wave equation, we have already obtained a global solution, its decay rate and finite‐time blow‐up [1]. In this paper, we extend these results to a coupled system. First, we obtain a global solution and derive its decay rate by a decreasing energy. Finally, we apply the concavity method in order to show that the solution blows up in finite time under nonclassic constraint on kernel functions. [ABSTRACT FROM AUTHOR]

Viruses span an impressive size range, with genome length varying a thousandfold and virion volume nearly a millionfold. For cellular organisms the scaling of traits with size is a pervasive influence on ecological processes, but whether size plays a central role in viral ecology is unknown. Here, we focus on viruses of aquatic unicellular organisms, which exhibit the greatest known range of virus size. We outline hypotheses within a quantitative framework, and analyse data where available, to consider how size affects the primary components of viral fitness. We argue that larger viruses have fewer offspring per infection and slower contact rates with host cells, but a larger genome tends to increase infection efficiency, broaden host range, and potentially increase attachment success and decrease decay rate. These countervailing selective pressures may explain why a breadth of sizes exist and even coexist when infecting the same host populations. Oligotrophic ecosystems may be enriched in "giant" viruses, because environments with resource‐limited phagotrophs at low concentrations may select for broader host range, better control of host metabolism, lower decay rate and a physical size that mimics bacterial prey. Finally, we describe where further research is needed to understand the ecology and evolution of viral size diversity. [ABSTRACT FROM AUTHOR]

Optimised quantity of nano‐aluminium (Al) filler mixed with epoxy resin using percolation threshold criteria was adapted to fabricate nanocomposite with desired space‐charge and charge‐trap properties. Surface potential variation due to charge deposition on to the insulating material under transient voltages was investigated, and it showed the improved decay rate with reduced trap depth for the nanocomposites with nanofillers addition in the range between 0.5 and 5 wt%. Threshold electric field calculated based on space‐charge density variation by pulsed electroacoustic measurement was found to be between 7–9 kV/mm and maximum electric field calculated through polarity reversal test is about 9 kV/mm, for 5 wt% (for the optimised value of nanofiller) epoxy nano‐Al composites. [ABSTRACT FROM AUTHOR]

We consider a viscoelastic wave equation with power nonlinearity. First, we construct a local solution by the Faedo‐Galerkin approximation scheme and contraction mapping theorem. Next, we continue the local solution to the global one by a priori estimates obtained from a decreasing energy. Finally, we discuss the decay rate of the global solution by assuming that the kernel function is convex. [ABSTRACT FROM AUTHOR]

Environmental DNA (eDNA) analysis has successfully detected organisms in various aquatic environments. However, there is little basic information on eDNA, including the eDNA shedding and degradation processes. This study focused on water temperature and fish biomass and showed that eDNA shedding, degradation, and size distribution varied depending on water temperature and fish biomass. The tank experiments consisted of four temperature levels and three fish biomass levels. The total eDNA and size‐fractioned eDNA from Japanese Jack Mackerels (Trachurus japonicus) were quantified before and after removing the fish. The results showed that the eDNA shedding rate increased at higher water temperature and larger fish biomass, and the eDNA decay rate also increased at higher temperature and fish biomass. In addition, the small‐sized eDNA fractions were proportionally larger at higher temperatures, and these proportions varied among fish biomass. After removing the fish from the tanks, the percentage of eDNA temporally decreased when the eDNA size fraction was >10 µm, while the smaller size fractions increased. These results have the potential to make the use of eDNA analysis more widespread in the future. This study showed that the Japanese Jack Mackerel eDNA shedding rate increased at higher water temperatures and larger fish biomass, and the most supported model for the eDNA decay curves included both temperature and fish density as explanatory variables. In addition, eDNA size distribution varied depending on temperature, fish biomass, and time passage. [ABSTRACT FROM AUTHOR]

The effect of a homogeneous weak magnetic field on the decay process of a neutral scalar particle to a pair of charged fermions is studied. The decay rate is calculated through the imaginary part of the self‐energy of the scalar particle interacting with the charged fermions, at one loop. The weak field approximation can be performed in different ways, depending on the hierarchy of scales. Here, we explore the regime where the progenitor particle has a high transverse momentum and we find that the process is favored by the increase of the magnetic field. We compare our results with recent findings for a different kinematical regime and briefly discuss the possible physical reasons for the different behaviors. The phenomenon can be relevant in early universe events or in high‐energy collisions. [ABSTRACT FROM AUTHOR]

No in‐depth studies covering litter decomposition were previously conducted on afforested postmining sites despite the importance of litter decomposition on soil formation, especially in degraded areas. We aimed to compare leaf litter decomposition rates of 14 tree species growing in mixed stands on a postmining spoil heap, and to compare their decay rates with those obtained in pure stands of tree species that are very often planted in postmining areas. The study was conducted on the Bełchatów Lignite Mine spoil heap, central Poland. We studied litter decomposition rates over 5 years using the litterbag method. Leaf litter decomposition rates (k constants; yr−1) after 5 years of the experiment were arranged from highest to lowest as follows: Prunus serotina (1.04), Alnus glutinosa (0.86), Fraxinus excelsior (0.81), Ulmus laevis (0.73), Acer pseudoplatanus (0.68), Populus tremula (0.63), Populus × canadensis (0.59), Betula pendula (0.54), Populus nigra 'Italica' (0.38), Quercus rubra (0.36), Pinus sylvestris (0.34), Robinia pseudoacacia (0.34), Fagus sylvatica (0.25), and Quercus robur (0.22). Decomposition rates increased with Mg, Ca, and summed Mg + Ca + P + K contents in freshly fallen leaves (%). All species‐specific decomposition rates were higher in mixed than in Scots pine stands. Half of them were also higher than in pure stands of other tree species. Our results indicate that tree species composition could significantly affect the physiochemical properties of upper soil horizons on reclaimed areas. Based on these findings, we recommend planting high share of not only A. pseudoplatanus, A. glutinosa, and U. laevis but also F. sylvatica and Q. robur in stands on postmining spoil heaps, because mixed stands can accelerate soil development more than pure stands. [ABSTRACT FROM AUTHOR]

In this paper, we numerically investigate the BBM‐Burgers equation with a nonlocal viscous term u t + u x − β u t x x + ν π ∂ ∂ t ∫ 0 t u ( s ) t − s d s + γ u u x = α u x x , where 1 π ∂ ∂ t ∫ 0 t u ( s ) t − s d s is the Riemann‐Liouville half derivative. In particular, we implement different numerical schemes to approximate the solution and its asymptotical behavior. Also, we compare our numerical results with those given in for similar models. [ABSTRACT FROM AUTHOR]

In this paper, we numerically study the water wave model with a nonlocal viscous term u t + u x + β u x x x + ν D 1 / 2 u ( t ) + γ u u x = α u x x , where D 1 / 2 u ( t ) = 1 π ∂ ∂ t ∫ 0 t u ( s ) t − s d s is the Riemann‐Liouville half‐order derivative in time. We propose and compare different numerical schemes based on the diffusive realizations of fractional operators. [ABSTRACT FROM AUTHOR]

The optical bistability (OB) in the quantum dot molecules with four energy levels in a unidirectional ring cavity has been investigated. The authors find that the OB behaviour in the proposed system can be controlled by the system's different parameters such as electronic cooperation parameter, Rabi frequency of the two coupling laser field, decay rate, three frequency detuning, in which the parameters sensitivity is studied. The proposed system can be used for all optical switching and logic. [ABSTRACT FROM AUTHOR]

In this paper, we consider the Bresse‐Cattaneo system with a frictional damping term and prove some optimal decay results for the L2‐norm of the solution and its higher order derivatives. In fact, we show that there is a completely new stability number δ that controls the decay rate of the solution. To prove our results, we use the energy method in the Fourier space to build some very delicate Lyapunov functionals that give the desired results. We also prove the optimality of the results by using the eigenvalues expansion method. In addition, we show that for the absence of the frictional damping term, the solution of our problem does not decay at all. This result improves some early results [ABSTRACT FROM AUTHOR]

This study investigates the stochastic suppression and stabilisation of non‐linear hybrid delay systems with general one‐sided polynomial growth condition and decay rate. Given an unstable non‐linear hybrid delay system x˙(t)=f(x(t),x(t−τ(t)),r(t),t) with general one‐sided polynomial growth condition, the authors introduce two independent Brownian noise and perturb this system into stochastic hybrid delay system dx(t)=f(x(t),x(t−τ(t)),r(t),t)dt+h(x(t),r(t),t)dB1(t)+g(x(t),r(t),t)dB2(t). It is shown that the non‐linear diffusion term g(x(t),r(t),t) may suppress the potential explosion of hybrid delay system. Under a stronger condition, another linear diffusion term h(x(t),r(t),t) will make the perturbed stochastic hybrid delay system is almost surely stable with general decay rate. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with optimal decay rates for higher‐order spatial derivatives of classical solution to the compressible Navier‐Stokes‐Maxwell equations in three‐dimensional whole space. If the initial perturbation is small in H 3 ∩ L 1‐norm, we apply the Fourier splitting method to establish optimal decay rates for the second‐order spatial derivatives of a solution. As a by‐product, the rate of classical solution converging to the constant equilibrium state in L ∞‐norm is ( 1 + t ) − 3 2. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the exponential stability analysis of linear delay difference systems. Firstly, a set of weighted discrete orthogonal polynomials (WDOPs) is established by using the Gram‐Schmidt orthogonalization process, and then two WDOPs‐based summation inequalities, including some existing summation inequalities as special cases, are developed. Secondly, these WDOPs‐based summation inequalities are applied to investigate the exponential stability criteria and explicit exponential estimates of solutions of linear delay difference systems. Finally, two numerical examples indicate that the proposed WDOPs‐based approach can derive the exponential stability condition with larger decay rate than the existing ones. [ABSTRACT FROM AUTHOR]

The advent of environmental DNA ( eDNA) analysis methods has enabled rapid and wide-range ecological monitoring in aquatic ecosystems, but there is a dearth of information on eDNA degradation. The results of previous studies suggest that the decay rate of eDNA varies depending on the length of DNA fragments. To examine this hypothesis, we compared temporal change in copy number of long eDNA fragments (719 bp) with that of short eDNA fragments (127 bp). First, we isolated rearing water from a target fish species, Japanese Jack Mackerel ( Trachurus japonicus), and then quantified the copy number of the long and short eDNA fragments in 1 L water samples after isolating the water from the fish. Long DNA fragments showed a higher decay rate than short fragments. Next, we measured the eDNA copy numbers of long and short DNA fragments using field samples, and compared them with fish biomass as measured by echo intensity. Although a previous study suggested that short eDNA fragments could be overestimated because of nontarget eDNA from a nearby fish market and carcasses, the eDNA concentrations of long fragments were correlated with echo intensity. This suggests that the concentration of longer eDNA fragments reflects fish biomass more accurately than the previous study by removing the effects of the fish market and carcasses. The length-related differences in eDNA have a substantial potential to improve estimation of species biomass. [ABSTRACT FROM AUTHOR]

In this work, we consider a nonlinear coupled wave equations with initial-boundary value conditions and nonlinear damping and source terms. Under suitable assumptions on the damping terms and source terms and initial data in the stable set, we obtain that the decay estimates of the energy function is exponential or polynomial by using Nakao's method. By using the energy method, we obtain the blow-up result of solution with some positive or nonpositive initial energy. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We study the convergence to equilibria, as time tends to infinity, of trajectories of dissipative wave systems with time-dependent velocity feedbacks and subject to nonlinear potential energies. Estimates for the speed of convergence are obtained in terms of the damping coefficient and the Łojasiewicz-Simon exponent. We allow for both restoring and amplifying effects of exterior forces, which makes our results possess wide applicability. As an example of application, we show that the trajectories of a sine-Gordon system, with nonautonomous damping, approach equilibria at least polynomially. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we consider the Bresse system coupled with the Fourier law of heat conduction. We prove that the decay rate of the solution is very slow. In fact, we show that the L2-norm of the solution decays with the rate of (1 + t)-1/12 similar to the one obtained for the Timoshenko system. In addition, we found that the wave speed of the first two equations still control the decay rate of the solution with respect to the regularity of the initial data. This seems to be the first result dealing with the behavior of the Cauchy problem in the Bresse-Fourier model. [ABSTRACT FROM AUTHOR]

The sensitivity of organic-rich archaeological layers at Bryggen in Bergen, Norway, to changes in soil temperatures, water contents and oxygen concentrations is investigated. This is done by linking measurements of oxic decay at varying temperatures and water contents with on-site monitoring data using a one-pool decomposition model. The results show that the model can be used to elucidate the current in situ decay and to evaluate where and when the decay takes place. Future investigations need to include long-term incubation experiments and decay studies at zero or very low oxygen contents in order to improve the robustness of predictions. [ABSTRACT FROM AUTHOR]

This study is concerned with the dominant pole analysis of asymptotically stable time‐delay positive systems (TDPSs). It is known that a TDPS is asymptotically stable if and only if its corresponding delay‐free system is asymptotically stable, and this property holds irrespective of the length of delays. However, convergence performance (decay rate) should degrade according to the increase of delays and this intuition motivates us to analyse the dominant pole of TDPSs. As a preliminary result, in this study, the authors show that the dominant pole of a TDPS is always real. They also construct a bisection search algorithm for the dominant pole computation, which readily follows from recent results on α ‐exponential stability of asymptotically stable TDPSs. Then, they next characterise a lower bound of the dominant pole as an explicit function of delays. On the basis of the lower bound characterisation, they finally show that the dominant pole of an asymptotically stable TDPS is affected by delays if and only if associated coefficient matrices satisfy eigenvalue‐sensitivity condition to be defined in this study. Moreover, they clarify that the dominant pole goes to zero (from negative side) as time‐delay goes to infinity if and only if the coefficient matrices are eigenvalue‐sensitive. [ABSTRACT FROM AUTHOR]

Valnoctamide ( VCD), a derivative of valproate, suppresses electrographic seizures in animal models of status epilepticus ( SE), even when the seizures are resistant to benzodiazepines ( BZDs). We therefore tested the effect of VCD on miniature inhibitory postsynaptic currents (m IPSCs) in CA1 pyramidal cells to determine if VCD acts directly on γ-aminobutyric acid ( GABA)A receptors. Bath-applied VCD induced a specific, rapid, dose-dependent, and reversible slowing of the decay of m IPSCs (i.e., increased time constant) with no effect on their frequency or amplitude. This is similar to the effect of BZDs on m IPSCs, but the effect of VCD persisted in the presence of the BZD-binding site antagonist flumazenil, and was additive to the effect of the BZD, diazepam. These data suggest that VCD acts through a different binding site than that of BZDs, which likely accounts for its effect on BZD-refractory SE. A PowerPoint slide summarizing this article is available for download in the Supporting Information section . [ABSTRACT FROM AUTHOR]

The degradation of archaeological wood at freezing and thawing temperatures is studied at the site of Qajaa in West Greenland through a combination of environmental monitoring, measurement of oxygen consumption and microscopy of wood samples. Permanently frozen wood is still very well preserved after 2-4000 years, while wood samples that thaw every summer show attack by soft rot and an average density loss of 0.1 g cm-3 (corresponding to 25% of the dry mass) over the past 27 years. Future increases in temperature may increase the decay rate significantly ( Q10 = 4.2 at 0-10°C) but the effects on site depend on local hydrology. [ABSTRACT FROM AUTHOR]

This article describes the first systematic investigation of how the efficiency roll-off in organic light-emitting diodes (OLEDs) is influenced by the position and orientation of the emitter molecules within the OLED cavity. The efficiency roll-off is investigated for two OLED stacks containing either the phosphorescent emitter Ir(MDQ)2(acac) or Ir(ppy)3 by varying the distance between emitter and metal cathode; a strong influence of emitter position and orientation on roll-off is observed. The measurements are modeled by triplet-triplet-annihilation (TTA) theory yielding the critical current density and the TTA rate constant. It is found that Ir(MDQ)2(acac) shows the lowest roll-off when the emitter is located in the first optical maximum of the electromagnetic field, whereas the roll-off of the Ir(ppy)3 stack is lowest when the emitter is positioned closer to the metal cathode. Measurement and modeling of time-resolved electroluminescence show that the different roll-off behavior is due to the different orientation and the corresponding change of the decay rate of the emissive dipoles of Ir(MDQ)2(acac) and Ir(ppy)3. Finally, design principles are developed for optimal high-brightness performance by modeling the roll-off as a function of emitter-cathode distance, emissive dipole orientation, and radiative efficiency. [ABSTRACT FROM AUTHOR]

ABSTRACT The ecological responses of large rivers to human pressure can be assessed at multiple scales using a variety of indicators, but little is known about how the responses of ecological indicators vary over small spatial scales. We sampled phytoplankton, zooplankton and macroinvertebrates and measured river metabolism and cotton strip breakdown rates (loss in tensile strength) in contrasting habitats along a 21-km urban-industrial reach on a constrained section of the Waikato River, New Zealand's longest river. Rates of gross primary production (2.8-7.8 g O2/m2/d) and ecosystem respiration (3.5-12.7 g O2/m2/d) did not differ consistently between near-shore (2-3 m from river side) and far-shore (ca. 10 m from side) locations, urban and industrial reaches or between autumn and spring sampling occasions. Rates of cotton decay (− k) ranged from 0.014 to 0.112 per day and were typically faster at far-shore locations and in the section of river receiving industrial inputs, but slower in spring compared with autumn. Nonmetric multidimensional scaling analysis of phytoplankton and zooplankton data did not reveal spatial patterns relating to pressure or location (embayment, edge, mid-river). However, the macroinvertebrate ordination suggested distinct communities for the mid-river benthos compared with near-shore communities and a distinction between sites in the urban reach and the industrial reach. Our results suggest that large-river macroinvertebrate communities and cotton decay rates can be influenced to varying degrees by reach-scale pressures and local habitat conditions. Monitoring designs in spatially complex rivers should account for habitat heterogeneity that can lead to differences in structural and functional indicator responses. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We consider the asymptotic behavior of the strong solution to the incompressible magnetohydrodynamics (MHD) equations in a half space. The L r-decay rates of the strong solution and its derivatives with respect to space variables and time variable, including the L1 and L ∞ decay rates of its first order derivatives with respect to space variables, are derived by using L q − L r estimates of the Stokes semigroup and employing a decomposition for the nonlinear terms in MHD equations. In addition, if the given initial data lie in a suitable weighted space, we obtain more rapid decay rates than observed in general. Similar results are known for incompressible Navier-Stokes equations in a half space under same assumption. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We investigate the effect of silver nanostructures and nanofilms on fluorescence resonance energy transfer (FRET). Thin layers of poly (vinyl alcohol) of 10 or 20 nm with homogenously distributed donor (Cy3) and acceptor (Cy5) molecules were coated on silver islands and continuous silver films. Several geometrical configurations were studied with multiple donor-acceptor (D-A) samples with various acceptor concentrations. The acceptor concentrations were adjusted to yield FRET efficiencies from about 10 to 92% on bare glass surfaces. Time-resolved fluorescence spectroscopy was used to determine the energy transfer efficiency and the relative transfer rate. It was found that the relative transfer rate increased 2-fold in the presence of continuous silver films and about 25-fold in presence of silver island films. The largest enhancements in the energy transfer efficiency, up to 90%, were observed for low acceptor concentrations (large donor-acceptor separations). To a first approximation, observed changes in FRET efficiencies were explained by an increase of the quantum yield of the donor molecules in the presence of silver islands. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The article relates a study which estimates orangutan nests in a lowland forest in East Kalimtan, Indonesia, using an established line-transect methodology. The decay of 663 nests was monitored for 20 months. The decay time of 602 days was calculated using Markov chain analysis. The study reveals a lower population density estimate, suggestive that short-term studies where decay times are determined using matrix mathematics may produce unreliable decay times. The authors noted that their findings have implications for other parts of the orangutan range where population estimates are based on potentially unreliable nest decay estimates.

The article focuses on a study related to examining the modes of decay and temporal patterns in the availability of Picea abies logs in an old-growth forest affected by internal disturbance. The study was conducted in Norra Gardfjäallet State Forest Reserve in Västerbotten County, Sweden. Almost 90 percent of the logs took about 60 years to decay beyond a deformed trunk with soft wood. Heart-rot fungi were found to be important factors behind the dynamics of dead wood. The impact of log size on wood decay rates was also examined.

Abstract: Structural properties of a bacterial luciferase mutant, evolved by random mutagenesis, have been investigated. Bacterial luciferases (LuxAB) can be readily classed as slow or fast decay luciferases based on their rates of luminescence decay in a single turnover assay. By random mutagenesis, one of the mutants generated by a single mutation on LuxA at position 175 (E175G) resulted in the “slow decay” Xenorhabdus luminescens luciferase was converted into a luciferase with a significantly more rapid decay rate [Hosseinkhani, S., Szittner, R. and Meighen, E.A. (2005) Biochemical Journal 385, 575–580]. A single mutation (E175G), in a loop that connects α helix 5 and β sheet 5 brought about changes in the kinetic and structural properties of the enzyme. Enhancement of tryptophan fluorescence was observed with a lower degree of fluorescence quenching by acrylamide upon mutation. Near- and far-UV circular dichroism spectra of the native and mutant forms suggested formation of an intermediate structure, further supported by 8-anilino-1-naphthalene-sulphonic acid (ANS) fluorescence which indicated lower exposure of hydrophobic residues as a result of mutation. Fluorescence quenching studies utilizing acrylamide indicated a more accessible fluor for the native form. Thus, the E175G point mutation appears to change the enzymatic decay rate by inducing a substantial tertiary structural change, without a large effect on secondary structural elements, as revealed by Fourier transform IR spectroscopy. Overall, the mutation caused structural changes that go beyond the simple change in orientation of Glu175. [Copyright &y& Elsevier]

Filamentous bulking in activated sludge systems occurs when filamentous organisms outgrow floc-forming bacteria and interfere with sludge settling. The competition between filaments and floc formers has been described previously using the kinetic selection and filamentous backbone theories. We hypothesized that differences in decay rates and storage abilities also affect this competition. We tested this hypothesis by integrating these four factors into a substrate-utilization model to predict and explain coexistence in a completely mixed reactor. In addition, filamentous and nonfilamentous sludges were developed in laboratory-scale reactors and analyzed to determine decay rates. The modeling results showed coexistence of the two organism types, and sensitivity analysis showed that the kinetic parameters, storage rate constants, and backbone coefficient had the greatest effect on the simulation results. Monte Carlo simulation showed the effect of storage, and the ranges of dilution rates wherein one group outcompeted the other were delineated. [ABSTRACT FROM AUTHOR]

Summary An ESR (Electron Spin Resonance) investigation on irradiated dry broad bean gave a spectrum which was composed of an equally spaced sextet and a single resonance line. These lines appeared at g = 2.0045 (±0.0005) and originated from Mn2+ ions and radiation induced radicals, respectively. Ground broad bean was used throughout the work to avoid any artefacts arising from a microwave cavity filling factor. Free radical signal intensity was observed to increase exponentially in relation to the increase in absorbed dose over the dose range 1.25–15 kGy. Although the Mn2+ signal increases below room temperature, the signal due to the natural and radiation induced radicals decreases. Above room temperature, they both decreased and these decreases were irreversible. The kinetics of these decreases were studied in detail over a temperature range of 308–373 K by annealing samples at different temperatures for various times. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the vibratory characteristics of three designs of the Class I Kennedy maxillary removable partial denture frameworks as the basic study. Their major connectors comprised a U-shaped palatal connector (UPC), single palatal bar (SPB), and anterior–posterior palatal bars (APB). Frequency response functions were measured when the framework was impacted. The modal shape was observed and the decay rate was calculated using modal analysis software. The results showed that the vibratory properties of each framework differed from each other. Within the range of frequencies from 10 to 2000 Hz, the UPC type had seven natural frequencies, while the SPB and the APB types had six. The UPC type had a greater number of natural modes accompanied by elastic deformation, including fluttering and twisting, than the other type, and the UPC type was considered to be unfavourable. The decay rate of the APB type was significantly higher than those of the UPC and the SPB types (P < 0·01). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of the continuous compression assumed as a result of light clenching on the blood flow of the denture underlying mucosa in tissue-supported or tooth-tissue-supported denture wearers. Measurements were carried out on eight removable partial denture wearers (three males and five females, from 50 to 72 years, mean age: 61·5 years). The blood flow in the denture underlying mucosa was measured at the unilateral mandibular first molar region using an experimental denture base equipped with a laser Doppler flowmeter. The area of the experimental denture base was 2 cm2 , and the loading force was 1 kgf. The loading time was set at 5, 10, 20, 30 and 60 s. The blood flow after 20 s loading was <15% in rest. The times from release of loading to the maximum blood flow and from release of loading to recovery up to 110% of the blood flow at pre-loading were significantly prolonged by an increase in the loading time. Even if it is light, a continuous clenching results in ischaemia and delays the recovery of blood flow in the mucosa underlying the denture after release of compression. [ABSTRACT FROM AUTHOR]

Many fungi commonly isolated (> 5% isolation frequency) from dead attached ash (Fraxinus excelsior L.), beech (Fagus sylvatica L.) and oak (Quercus robur L.) twigs were capable of growth at water potentials below -6 MPa, including Phomopsis spp., Cryptosporiopsis spp., Libertella fraxinea Oganova, Fusarium lateritium Nees. and Aureobasidium pullulans (De Bary) Arnaud. Several of these underwent morphological switches at low water potentials. Growth of almost all basidiomycetes common in dead twigs, including Peniophora spp. and Vuilleminia comedens (Nees. : Fr.) Maire, was inhibited at water potentials below -4 MPa. The ecology of fungi commonly isolated from dead ash twigs was studied in greater detail. All except Peniophora lycii (Pers.) V. Hohn & Litch and L. fraxinea, survived in wood for 1 yr at extremely low water potentials (below -200 MPa). P. lycii was the only species that grew at low temperatures (<5 °C). Water potential was a major determinant of decay rate. Generally, even at high water potentials, decay by individual fungi over a 1 yr period was limited to 20-30% dry weight losses. However, at -0.05 and -0.8 MPa P. lycii caused 70% weight loss, and L. fraxinea caused 50% weight loss at -4.1MPa (its optimal water potential for decay). At water potentials between -4 and -9 MPa L. fraxinea, Phomopsis platanoidis Died. and unidentified sp. 12 were capable of producing significant lignocellulose decay. [ABSTRACT FROM AUTHOR]

Pharmacokinetic studies of biomarkers for environmental contaminantsin humans are generally restricted to a few measurements per subjecttaken after the initial exposure. Subjects are selected for inclusion in the study if their measured body burden is above a threshold determined by the distribution of the biomarker in a control population.Such selection procedures introduce bias in the ordinary weighted least squares estimate of the decay rate lambda caused by the truncation. We show that if the data are conditioned to lie above a line with slope - lambda on the log scale then the weighted least squares estimate of lambda is unbiased. We give an iterative estimation algorithm that produces this unbiased estimate with commercially available software for fitting a repeated measures linear model. The estimate and its efficiency are discussed in the context of a pharmacokinetic studyof 2,3,7,8-tetrachlorodibenzo-p-dioxin. Unbiasedness and efficiency are demonstrated with a simulation. [ABSTRACT FROM AUTHOR]