Pulse Solutions Research Articles

Efficacy of postharvest treatments with sodium nitroprusside and gibberellic acid on physio-biochemical modifications and vase life of dahlia cut flower

The goal of the current study was to evaluate the impacts of both sodium nitroprusside (SNP) and gibberellic acid (GA3) separately and in combination on the longevity of Dahlia cut flowers. Additionally, the potential physiological and biochemical changes associated with these treatments are also examined. Cut flowers treated with nitric oxide donor SNP and GA3 significantly improved all postharvest characteristics of cut flowers, including vase life and other physiological characteristics, as compared to control. Flowers treated with T15 (SNP 20 mg L-l + GA3 20 mg L-l) resulted in maximum vase life, followed by treatment T3 (SNP 20 mg-l) and minimum vase life recorded in control. Treatment T15 (SNP 20 mg L-l + GA3 20 mg L-l) shows an improvement in all biochemical activities, including superoxide dismutase, catalase, and peroxidase activity, except malondialdehyde accumulation, as compared with untreated cut flowers. Thus, SNP alone or along with GA3 as a pulsing solution could be a promising approach to improving the postharvest quality of dahlia cut flowers by influencing physiological and biochemical modifications.

Polypropylene Packaged Ten Days Cold Stored Rose Cut Flowers cv. Bordeaux Influenced by Different Pulsing Solution

The study included different pulsing solution viz., water, HQC 200mg/l, sucrose 50g/l + HQC 200 mg/l, citric acid 200mg/l, α-lipoic acid 200mg/l, GA3 100 mg/l and BA 100mg/l to study the effect on flower quality and vase life of PP (polypropylene) packaged cold storage (at 2°C) rose cv. Bordeaux, for the period of 10 days. Pre-storage pulsing of GA3 100mg/l solution treatment showed highly promising results in extending flowers vase life along with maintained flower quality just after storage and at 4th DAS in vase life. Further, GA3 100mg/l solution treatment recorded significantly higher water up take (175.65 ml), change in fresh weight (10.50%) at 4th DAS, total dissolve solids (8.85 °brix, 8.05 °brix and 6.75 °brix) and membrane stability index (81.97 %, 65.97 % and 37.88 %) at 2nd, 4th and 6th DAS. Moreover, it was evident from the results that same treatment recoded significantly higher total soluble sugar (59.65 mg/g fresh weight), Estimated protein (18.79 mg/g fresh weight), catalase activity (20.42 µ mol H2O2 min-1 g-1 protein), peroxidation activity (40.30 µ mol H2O2 min-1 g-1 protein), pigment content (15.82 mg/g fresh weight) anthocyanin content in the petals at 4th DAS. Whereas, GA3 100 mg/l pulsing solution treated PP packaged cold stored rose cut flowers cv. Bordeaux recorded significantly higher vase life (6.88 days) which was at par with treatment P2 (Sucrose 50 g/l + HQC 200 mg/l).

Pulse instabilities can shape virus-immune coevolution

Adaptive immune systems engage in an arms race with evolving viruses, trying to generate new responses to viral strains that continually move away from the set of genetically varying strains that have already elicited a functional immune response. It has been argued that this dynamical process can lead to a propagating pulse of an ever-changing viral population and concomitant immune response. Here, we introduce a new stochastic model of viral-host coevolution, taking into account finite-sized host populations and varying processes of immune “forgetting”. Using both stochastic and deterministic calculations, we show that there is indeed a possible pulse solution, but for a large host population size and for finite memory capacity, the pulse becomes unstable to the generation of new infections in its wake. This instability leads to an extended endemic infection pattern, demonstrating that the population-level behavior of virus infections can exhibit a wider range of behavior than had been previously realized. Published by the American Physical Society 2024

Pulsed corona discharge: an advanced treatment method for antibiotic-contaminated water

Water pollution is one of the most significant problems of the current century. With the increase in medicine availability and use, pharmaceutical pollutants such as antibiotics become more prevalent in natural environments with potentially negative impact. In this study, a pulsed corona discharge was investigated as a possible treatment method of water contaminated with amoxicillin (AMX). Two system configurations were used: plasma and plasma-ozonation. In order to better grasp the effect of system and water matrix on degradation, different pulse widths, solutions pH and conductivity values, as well as the nature of the dissolved salts were investigated. Decreasing the pulse width from 300 ns to 106 ns (full width at half maximum) led to almost a two-fold increase in energy yield at 50% pollutant removal, and the addition of the ozonation reactor resulted six times enhancement in efficiency. While the water matrix had little impact on AMX degradation, the buffering capacity of carbonates has proven beneficial by preventing pH decrease during treatment. Under optimum conditions, the energy yield was 57 g kWh−1 at 93% removal of AMX in tap water. A number of 26 potential degradation products have been identified, resulting from hydroxylation of the benzene ring, oxidation of the thioester and amine groups, hydrolysis, and cleavage of the benzene, β-lactam and thiazole rings, along with fragmentation of the resulting compounds. All but seven degradation intermediates are completely removed by extending treatment duration to 60 min and the persistent ones are less toxic than the parent compound.

Travelling pulses on three spatial scales in a Klausmeier-type vegetation-autotoxicity model

Reaction-diffusion models describing interactions between vegetation and water reveal the emergence of several types of patterns and travelling wave solutions corresponding to structures observed in real-life. Increasing their accuracy by also considering the ecological factor known as autotoxicity has lead to more involved models supporting the existence of complex dynamic patterns. In this work, we include an additional carrying capacity for the biomass in a Klausmeier-type vegetation-water-autotoxicity model, which induces the presence of two asymptotically small parameters: ɛ, representing the usual scale separation in vegetation-water models, and δ, directly linked to autotoxicity. We construct three separate types of homoclinic travelling pulse solutions based on two different scaling regimes involving ɛ and δ, with and without a so-called superslow plateau. The relative ordering of the small parameters significantly influences the phase space geometry underlying the construction of the pulse solutions. We complement the analysis by numerical continuation of the constructed pulse solutions, and demonstrate their existence (and stability) by direct numerical simulation of the full partial differential equation model.

Lax pairs informed neural networks solving integrable systems

Lax pairs are one of the most important features of integrable system. In this work, we propose the Lax pairs informed neural networks (LPNNs) tailored for the integrable systems with Lax pairs by designing novel network architectures and loss functions, comprising LPNN-v1 and LPNN-v2. The most noteworthy advantage of LPNN-v1 is that it can transform the solving of complex integrable systems into the solving of relatively simple Lax pairs, and it not only efficiently solves data-driven localized wave solutions, but also obtains spectral parameter and corresponding spectral function in spectral problems of the integrable systems. On the basis of LPNN-v1, we additionally incorporate the compatibility condition/zero curvature equation of Lax pairs in LPNN-v2, its major advantage is the ability to solve and explore high-accuracy data-driven localized wave solutions and associated spectral problems for integrable systems with Lax pairs. The numerical experiments focus on studying abundant localized wave solutions for very important and representative integrable systems with Lax pairs, including the soliton solution of the Korteweg-de Vries (KdV) equation and modified KdV equation, rogue wave solution of the nonlinear Schrödinger equation, kink solution of the sine-Gordon equation, non-smooth peakon solution of the Camassa-Holm equation and pulse solution of the short pulse equation, as well as the line-soliton solution of Kadomtsev-Petviashvili equation and lump solution of high-dimensional KdV equation. The innovation of this work lies in the pioneering integration of Lax pairs informed of integrable systems into deep neural networks, thereby presenting a fresh methodology and pathway for investigating data-driven localized wave solutions and spectral problems.

Traveling waves in a model of calcium ions influx via mechanically stimulated membrane channels

We consider the problem of existence and properties of pulse solutions to a system of equations modeling fast calcium waves in long cells. These waves have the speed up to 1000 m/s. They propagate via the inflow of calcium ions from the extracellular space through the mechanically stimulated membrane channels. The channels open due to mechano‐chemical interaction, in which stretching of the cell's membrane at a point opens the calcium channels at neighboring points due to the forces exerted by the actomyosin network. The existence of homoclinic solutions is based on the celebrated exchange lemma, which cannot be applied straightforwardly due to some specificities of the model equations.

Reflection of conormal pulse solutions to large variable-coefficient semilinear hyperbolic systems

We provide a rigorous justication of nonlinear geometric optics expansions for reflecting pulses in space dimensions n>1. The pulses arise as solutions to variable coefficient semilinear first-order hyperbolic systems. The justification applies to N×N systems with N interacting pulses which depend on phases that may be nonlinear. The coherence assumption made in a number of earlier works is dropped. We consider problems in which incoming pulses are generated from pulse boundary data as well as problems in which a single outgoing pulse reflects off a possibly curved boundary to produce a number of incoming pulses. Although we focus here on boundary problems, it is clear that similar results hold by similar methods for the Cauchy problem for N×N systems in free space.

Travelling modulating pulse solutions with small tails for a nonlinear wave equation in periodic media

Travelling modulating pulse solutions consist of a small amplitude pulse-like envelope moving with a constant speed and modulating a harmonic carrier wave. Such solutions can be approximated by solitons of an effective nonlinear Schrödinger equation arising as the envelope equation. We are interested in a rigorous existence proof of such solutions for a nonlinear wave equation with spatially periodic coefficients. Such solutions are quasi-periodic in a reference frame co-moving with the envelope. We use spatial dynamics, invariant manifolds, and near-identity transformations to construct such solutions on large domains in time and space. Although the spectrum of the linearised equations in the spatial dynamics formulation contains infinitely many eigenvalues on the imaginary axis or in the worst case the complete imaginary axis, a small denominator problem is avoided when the solutions are localised on a finite spatial domain with small tails in far fields.

Análise da degradação foliar de Lisianthus (Eustoma grandiflorum) na pós-colheita por espectroscopia de reflectância VIS-NIR-SWIR

ABSTRACT: It is known that floriculture is very important for the world economic scenario. Nevertheless, the vase life of cut flowers is determined by a short time span. This study evaluated the spectral behavior during leaf degradation of lisianthus (Eustoma grandiflorum) flower stems in the postharvest, in different preservative solutions, and estimating its leaf pigments by hyperspectral data. Lisianthus floral stems were subjected to preservative solutions with different concentrations of sucrose, glucose, phytohormones and deionized water. Leaves from these stems were collected every 4 days for further hyperspectral analysis. Spectra was determined in laboratory with a sensor collecting at the range of 350-2500 nm. In order to analyze the use of the spectra to detect the performance of the preservative solutions, statistical tests were used at each wavelength. Pigment prediction was assessed by the CAR/CLF ratio (Ratio between Carotenoids and Chlorophyll) from the spectral curves, using PLSR and RRMSE. The glucose-based solutions registered positive effects on the preservation of floral stems, especially at the dose of 180 g/L. The solutions based on sucrose and phytohormones registered similarities in the spectral curves among the doses, demonstrating equality in leaf preservation. The discriminant analyses demonstrated there was statistical difference in the spectral responses in the doses for each solution used. The CAR/CLF ratio had reasonable coefficients of 0.6 and RRMSE below 6.99%. The hyperspectral analyses presented a potential for the evaluation of leaf degradation in lisianthus floral stems in different pulsing solutions used in the postharvest.

Magnetic multi-walled carbon nanotubes modified with surface-imprinted polymers for ultrasensitive electrochemical detection of trace-level nickel ions in groundwater

Magnetic multi-walled carbon nanotubes (Fe3O4@MWCNTs) were synthesized utilizing a solvothermal technique in this study, followed by the synthesis of Ni(II)-imprinted polymers (IIP) using a surface imprinting technique in this study. The materials' morphologies, structures, and chemical compositions were characterized using several techniques: Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The IIP was loaded onto a carbon-paste electrode using differential pulsed anodic solution voltammetry (DPASV) to form an electrochemical sensor (IIP-CPE) that could effectively identify Ni(II). The effects of the electrode composition, solution pH, deposition potential, and deposition time on the response of the IIP-CPE electrochemical sensor to Ni(II) peak currents were also investigated. The IIP-CPE demonstrated secondary linearity within the concentration ranges of 0.5–20 μg/L and 20–200 μg/L for Ni(II), with a detection limit of 0.27 μg/L under optimized conditions. It also maintained good selectivity, anti-interference, reproducibility, and stability and showed good accuracy in actual water samples. The constructed IIP-CPE has promising applications for the rapid monitoring trace-level Ni(II) in water bodies.

Exposure to the insecticide, imidacloprid, impairs predator-recognition learning in damselfly larvae

Many aquatic organisms use chemosensory information to learn about local predation threats, but contaminants in their environment may impair such cognitive processes. Neonicotinoids are a class of water-soluble systemic insecticides that have become a major concern in aquatic systems. In this study, we explored how a 10-day exposure to various concentrations (0, 0.1, 1.0, or 10.0 μg/L) of the neonicotinoid imidacloprid affects the learned recognition of predator odour by non-target damselfly larvae (Lestes spp). Unexposed larvae and those exposed to the low concentration (0.1 μg/L) demonstrated an appropriate learned response to a novel predator odour following a conditioning with the odour paired with chemical alarm cues. However, such learning failed to occur for larvae that were exposed to imidacloprid concentrations of 1.0 and 10.0 μg/L. Thus, either the cognitive processing of the chemical information was impaired or the chemistry of one or both of the conditioning cues was altered, making them ineffective for learning. In a second experiment, we found evidence for this latter hypothesis. In the absence of background imidacloprid exposure, larvae did not show significant learned responses to the predator odour when the conditioning cues were mixed with imidacloprid (initial pulse solution of 3.0 μg/L) at the start of conditioning (reaching a final concentration of 0.01 μg/L). These findings indicate that even low levels of imidacloprid can have important implications for chemosensory cognition of non-target species in aquatic environments.

Velocity selective spin labeling using parallel transmission.

Ultra-high field (UHF) provides improved SNR which greatly benefits SNR starved imaging techniques such as perfusion imaging. However, transmit field (B1 + ) inhomogeneities commonly observed at UHF hinders the excitation uniformity. Here we show how replacing standard excitation pulses with parallel transmit pulses can improve efficiency of velocity selective labeling. The standard tip-down and tip-up excitation pulses found in a velocity selective preparation module were replaced with tailored non-selective kT -points pulse solutions. Bloch simulations and experimental validation on a custom-built flow phantom and in vivo was performed to evaluate different pulse configurations in circularly polarized mode (CP-mode) and parallel transmit (pTx) mode. Tailored pTx pulses significantly improved velocity selective labeling fidelity and signal uniformity. The transverse magnetization normalized RMS error was reduced from 0.489 to 0.047 when compared to standard rectangular pulses played in CP-mode. Simulations showed that manipulation of time symmetry in the tailored pTx pulses is vital in minimizing residual magnetization. In addition, in vivo experiments achieved a 44% lower RF power output and a shorter pulse duration when compared to using adiabatic pulses in CP-mode. Using tailored pTx pulses for excitation within a velocity selective labeling preparation mitigated transmit field artifacts and improved SNR and contrast fidelity. The improvement in labeling efficiency highlights the potential of using pTx to improve robustness and accessibility of flow-based sequences such as velocity selective spin labeling at ultra-high field.

Increasing the Vase Life of Chrysanthemum Cut Flowers by Using Silver and Zinc Nanoparticles.

Cut flowers are horticultural products that have great potential to be developed. Efforts to maintain quality and extend the shelf life of cut flowers are very important to obtain a product that is accepted in the market. The main problems of chrysanthemum cut flowers are the leaves easily turning yellow, wilting, and failure to fully open flowers. This study aimed to obtain the best pulsing solution formulation that increases vase life and maintains the freshness of chrysanthemum cut flowers. Pulsing solution treatment was carried out on chrysanthemum cut flowers during the evaluation period. Pulsing solution treatment consisted of control, AgNO3, nano-Ag (NAg), ZnO, and nano-Zn (NZn). The results showed that NAg20 treatment increased the vase life of chrysanthemum cut flowers up to 23 days, which was 19 days longer than the control. Nano-Ag inhibits bacterial growth, flower wilting, color degradation, and carotenoids. In addition, nano-Ag increased the size of the bloom-flower diameter. Considering the results of all postharvest quality parameters mentioned above, NAg20 extends the vase life of chrysanthemum cut flowers.

Effect of some chemical and natural preservative solutions on vase life, water relations and some chemical composition of Dianthus caryophyllus L. cut flowers

To investigate the effect of some pulsing and holding solutions on the quality of carnation cv. Turbo cut flowers, a laboratory experiment was conducted in the Agricultural Research Center and Cairo University, Egypt during 2020 and 2021 seasons. In this regard distilled water, silver thiosulfate (STS) at 0.4 ppm + sucrose 10% (PS1) and AgNO3 at 10.0 ppm + sucrose 10% (PS2) were employed as a pulsing solution for 15 min while distilled water, sucrose 4% (HS1), boric acid (BoA) at 200 ppm + sucrose 4% (HS2), 8-hydroxyquinoline sulfate (8-HQS) at 300 ppm + sucrose 4% (HS3), Amino-oxyacetic acid (AOA) at 250 ppm + sucrose 4% (HS4), 8-HQS + AOA + sucrose 4% (HS5), BoA + 8-HQS + sucrose 4% (HS6), BoA + AOA + sucrose 4% (HS7), BoA + 8-HQS + AOA + sucrose 4% (HS8), rosemary extract at 25% + sucrose 2% (HS9) and thyme extract at 25% + sucrose 2% (HS10) were used as holding solutions. Regarding pulsing solutions, PS2 and PS1 exhibited a positive effect on all studied traits, while the mastery was to HS8 concerning the effect of holding solutions. Pulsing cut carnations in a solution containing PS2 followed by holding in HS8 resulted in the highest values in terms of vase life, water balance, chlorophyll a, carotenoids and total sugars, while the highest water uptake and loss and chlorophyll b were obtained by pulsing in PS1 followed by holding in HS8. It is recommended to pulse carnation cv. Turbo cut flowers in AgNO3 at 10.0 ppm + sucrose 10% solution for 15 min followed by holding in BoA + 8-HQS + AOA + sucrose 4% for getting the longest vase life, enhancing water uptake and maintaining water balance. Additionally, this preservative solution effectively reduces chlorophyll degradation and preserves the content of carbohydrates throughout the postharvest period.

Influence of Different Pulsing Solutions on Postharvest Life of Tuberose (Polianthes tuberosa L.) cv. Prajwal

Tuberose flower (Polianthes tuberosa L.) is a perennial and bulbous flowering plant, related to the Amaryllidaceae family and now it is placed in family Agavaceae. The investigation entitled “Influence of different pulsing solutions on postharvest life of tuberose (Polianthes tuberosa L.) cv. Prajwal” was carried out at the experimental farm and laboratory of Department of Floriculture and Landscape Architecture, College of Horticulture, SVPUAT, Meerut during the year of 2021-22 & 2022-23. Experiment was laid out in Completely Randomized Design with 10 treatments and 3 replications. In the present experiment we aimed at prolonging the vase life and improving the quality of cut spike of tuberose by Pulsing or hydration procedure using different noble treatments in tuberose, as the main challenge was to reduce abscission of buds, initiation of bud opening mechanism and leaf yellowing due to the sensitivity, vascular infections, high rate of respiration and inhibition of ethylene production. These differences in physiological behavior of cut stem dipped in different pulsing solution are very important to consider when developing post harvest physiology of tuberose. In the present finding we have primarily focused and observed under the light of pertinent literature available substantiated with robust evidence thus we derived the overall best treatment for different parameters for improving the vase life of tuberose that were recorded under the treatment T9 (Sucrose 15% + 8-HQC 300 ppm) followed by the treatment T6 (Sucrose 10% + 8-HQC 300 ppm) and T8 (Sucrose 15% + 8-HQC 200 ppm) resulted in most of the postharvest parameters such as amount of pulsing solution consumed (13.16, 15.82 ml), days taken to opening of floret (2.53, 2.54 days), floret diameter (3.38, 3.40 cm), vase life (10.78, 10.80 days), weight change/loss in cut spike (13.29 %, 14.52 %), fungal infection, fragrance score (2.95, 2.96), freshness index (4.97, 4.98) and moisture content (89.89, 85.60, 83.21%).

Propagation of solitons in inhomogeneous birefringent nonlinear dispersive media

We study the existence and wave-speed management of nonlinear localized waves in an inhomogeneous birefringent nonlinear dispersive medium in the presence of external potential. The coupled nonlinear Schrödinger equation with varying coefficients which can be applied to model the interaction among the modes in nonlinear optics and in Bose–Einstein condensation is considered. By means of a complex transformation, we derive new types of periodic nonlinear waves for the present coupled system which are expressed in terms of Jacobi elliptic functions. Novel soliton pulse solutions including bright-dipole and bright–dark solutions are identified in the long-wave limit of these periodic solutions. As an application of these soliton pulses, we discuss their wave-speed management for the different choices of dispersion parameter. The results show that the varied dispersion parameter can be used to control effectively the wave speed of propagating localized waves.

The dynamics of unsteady frictional slip pulses

Self-healing slip pulses are major spatiotemporal failure modes of frictional systems, featuring a characteristic size [Formula: see text] and a propagation velocity [Formula: see text] ([Formula: see text] is time). Here, we develop a theory of slip pulses in realistic rate- and state-dependent frictional systems. We show that slip pulses are intrinsically unsteady objects-in agreement with previous findings-yet their dynamical evolution is closely related to their unstable steady-state counterparts. In particular, we show that each point along the time-independent [Formula: see text] line, obtained from a family of steady-state pulse solutions parameterized by the driving shear stress [Formula: see text], is unstable. Nevertheless, and remarkably, the [Formula: see text] line is a dynamic attractor such that the unsteady dynamics of slip pulses (when they exist)-whether growing ([Formula: see text]) or decaying ([Formula: see text])-reside on the steady-state line. The unsteady dynamics along the line are controlled by a single slow unstable mode. The slow dynamics of growing pulses, manifested by [Formula: see text], explain the existence of sustained pulses, i.e., pulses that propagate many times their characteristic size without appreciably changing their properties. Our theoretical picture of unsteady frictional slip pulses is quantitatively supported by large-scale, dynamic boundary-integral method simulations.

Transient behaviors of pulse breaking and recovering in a dispersion-managed mode-locked Yb fiber laser

Various pulse regimes have been discovered in mode-locked fiber lasers with carefully designed cavity setups. However, the transitions between different types of stable pulse solutions are rarely observed in a laser with the same cavity configuration. Here, we report on the experimental observation of the transformation from stretched pulses (SPs) to dissipative solitons (DSs) in an all-polarization-maintaining dispersion-managed mode-locked Yb fiber laser for the first time. By means of the time-stretch dispersive Fourier transform technique, the temporal and spectral dynamics of transient behaviors from pulse breaking to pulse recovering are identified in real time. It is revealed that the overdriven nonlinear effect induced by pump increase triggers the wave breaking of SPs, and the improved net-cavity dispersion originated from wavelength shift helps the self-recovering of DSs. Numerical simulations validate the experimental observations and bring insights to the understanding of transient nonlinear dynamics in ultrafast fiber lasers.

Controlling pulse stability in singularly perturbed reaction-diffusion systems

The aim of this paper is to investigate the use of Pyragas control on the stability of stationary, localized coherent structures in a general class of two-component, singularly perturbed, reaction-diffusion systems. We use noninvasive Pyragas-like proportional feedback control to stabilize a singular pulse solution to a two-component, singularly perturbed reaction-diffusion system. We show that in a significant region of parameter space, the control can be adjusted to stabilize an otherwise unstable pulse.