7,155 research outputs found

    Growth and physiological responses of Kandelia candel and Bruguiera gymnorrhiza to livestock wastewater

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    Growth and physiological responses of two mangrove species (Kandelia candel and Bruguiera gymnorrhiza) to livestock wastewater under two salinity conditions (seawater with salinity of 30p and freshwater) were examined in greenhouse pot-cultivation systems for 144 days. Wastewater treatment significantly enhanced growth of Kandelia candel and Bruguiera gymnorrhiza in terms of stem height, stem basal diameter, leaf production, maximum unit leaf area and relative growth rate. Wastewater discharges and salinity levels did not significantly change biomass partitioning of Kandelia candel, however, more biomass of Bruguiera gymnorrhiza was allocated to leaf due to wastewater discharges. In Bruguiera gymnorrhiza, contents of chlorophyll a and chlorophyll b increased with wastewater discharges but such increase was not observed in Kandelia candel. On the other hand, livestock wastewater increased leaf electric conductance in Kandelia candel but not in Bruguiera gymnorrhiza. The peroxidase activity in stem and root of Kandelia candel under both salinity conditions increased due to wastewater discharges, while the activity in root of the treated Bruguiera gymnorrhiza seedlings decreased under freshwater condition but increased at seawater salinity. The superoxide dismutase activity in treated Bruguiera gymnorrhiza decreased but did not show any significant change in Kandelia candel receiving livestock wastewater

    Calculation of two-particle quantities in the typical medium dynamical cluster approximation

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    The mean-field theory for disordered electron systems without interaction is widely and successfully used to describe equilibrium properties of materials over the whole range of disorder strengths. However, it fails to take into account the effects of quantum coherence and information of localization. Vertex corrections due to multiple backscatterings may drive the electrical conductivity to zero and make expansions around the mean field in strong disorder problematic. Here, we present a method for the calculation of two-particle quantities which enables us to characterize the metal-insulator transitions in disordered electron systems by using the typical medium dynamical cluster approximation. We show how to include vertex corrections and information about the mobility edge in the typical mean-field theory. We successfully demonstrate the application of the developed method by showing that the conductivity formulated in this way properly characterizes the metal-insulator transition in disordered systems

    Analytical results for random walk persistence

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    In this paper, we present the detailed calculation of the persistence exponent θ\theta for a nearly-Markovian Gaussian process X(t)X(t), a problem initially introduced in [Phys. Rev. Lett. 77, 1420 (1996)], describing the probability that the walker never crosses the origin. New resummed perturbative and non-perturbative expressions for θ\theta are obtained, which suggest a connection with the result of the alternative independent interval approximation (IIA). The perturbation theory is extended to the calculation of θ\theta for non-Gaussian processes, by making a strong connection between the problem of persistence and the calculation of the energy eigenfunctions of a quantum mechanical problem. Finally, we give perturbative and non-perturbative expressions for the persistence exponent θ(X0)\theta(X_0), describing the probability that the process remains bigger than X0X_0\sqrt{}.Comment: 23 pages; accepted for publication to Phys. Rev. E (Dec. 98

    Cardiovascular sequalae in uncomplicated COVID-19 survivors

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    BACKGROUND: A high proportion of COVID-19 patients were reported to have cardiac involvements. Data pertaining to cardiac sequalae is of urgent importance to define subsequent cardiac surveillance. METHODS: We performed a systematic cardiac screening for 97 consecutive COVID-19 survivors including electrocardiogram (ECG), echocardiography, serum troponin and NT-proBNP assay 1-4 weeks after hospital discharge. Treadmill exercise test and cardiac magnetic resonance imaging (CMR) were performed according to initial screening results. RESULTS: The mean age was 46.5 ± 18.6 years; 53.6% were men. All were classified with non-severe disease without overt cardiac manifestations and did not require intensive care. Median hospitalization stay was 17 days and median duration from discharge to screening was 11 days. Cardiac abnormalities were detected in 42.3% including sinus bradycardia (29.9%), newly detected T-wave abnormality (8.2%), elevated troponin level (6.2%), newly detected atrial fibrillation (1.0%), and newly detected left ventricular systolic dysfunction with elevated NT-proBNP level (1.0%). Significant sinus bradycardia with heart rate below 50 bpm was detected in 7.2% COVID-19 survivors, which appeared to be self-limiting and recovered over time. For COVID-19 survivors with persistent elevation of troponin level after discharge or newly detected T wave abnormality, echocardiography and CMR did not reveal any evidence of infarct, myocarditis, or left ventricular systolic dysfunction. CONCLUSION: Cardiac abnormality is common amongst COVID-survivors with mild disease, which is mostly self-limiting. Nonetheless, cardiac surveillance in form of ECG and/or serum biomarkers may be advisable to detect more severe cardiac involvement including atrial fibrillation and left ventricular dysfunction

    Persistence with Partial Survival

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    We introduce a parameter pp, called partial survival, in the persistence of stochastic processes and show that for smooth processes the persistence exponent θ(p)\theta(p) changes continuously with pp, θ(0)\theta(0) being the usual persistence exponent. We compute θ(p)\theta(p) exactly for a one-dimensional deterministic coarsening model, and approximately for the diffusion equation. Finally we develop an exact, systematic series expansion for θ(p)\theta(p), in powers of ϵ=1p\epsilon=1-p, for a general Gaussian process with finite density of zero crossings.Comment: 5 pages, 2 figures, references added, to appear in Phys.Rev.Let

    Scaling of thermal conductivity of helium confined in pores

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    We have studied the thermal conductivity of confined superfluids on a bar-like geometry. We use the planar magnet lattice model on a lattice H×H×LH\times H\times L with LHL \gg H. We have applied open boundary conditions on the bar sides (the confined directions of length HH) and periodic along the long direction. We have adopted a hybrid Monte Carlo algorithm to efficiently deal with the critical slowing down and in order to solve the dynamical equations of motion we use a discretization technique which introduces errors only O((δt)6)O((\delta t)^6) in the time step δt\delta t. Our results demonstrate the validity of scaling using known values of the critical exponents and we obtained the scaling function of the thermal resistivity. We find that our results for the thermal resistivity scaling function are in very good agreement with the available experimental results for pores using the tempComment: 5 two-column pages, 3 figures, Revtex

    Observation of bound states of solitons in a passively mode-locked fiber laser

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    We report on an experimental observation of bound states of solitons in a passively mode-locked fiber soliton ring laser. The observed bound solitons are stable and have discrete, fixed soliton separations that are independent of the experimental conditions

    Logarithmic perturbation theory for quasinormal modes

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    Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is briefly discussed. A numerical method is developed that handles the exponentially large wavefunctions which appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st
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