Indirect Signals Research Articles

Double Photodiode Readout System for the Calorimeter of the HERD Experiment: Challenges and New Horizons in Technology for the Direct Detection of High-Energy Cosmic Rays

The HERD experiment is a future experiment for the direct detection of high-energy cosmic rays and is to be installed on the Chinese space station in 2027. The main objectives of HERD are the first direct measurement of the knee of the cosmic ray spectrum, the extension of electron+positron flux measurement up to tens of TeV, gamma ray astronomy, and the search for indirect signals of dark matter. The main component of the HERD detector is an innovative calorimeter composed of about 7500 LYSO scintillating crystals assembled in a spherical shape. Two independent readout systems of the LYSO scintillation light will be installed on each crystal: the wavelength-shifting fibers system developed by IHEP and the double photodiode readout system developed by INFN and CIEMAT. In order to measure protons in the cosmic ray knee region, we must be able to measure energy release of about 250 TeV in a single crystal. In addition, in order to calibrate the system, we need to measure typical releases of minimum ionizing particles that are about 30 MeV. Thus, the readout systems should have a dynamic range of about 107. In this article, we analyze the development and the performance of the double photodiode readout system. In particular, we show the performance of a prototype readout by the double photodiode system for electromagnetic showers as measured during a beam test carried out at the CERN SPS in October 2021 with high-energy electron beams.

Plant-derived monoterpene S-linalool and β-ocimene generated by CsLIS and CsOCS-SCZ are key chemical cues for attracting parasitoid wasps for suppressing Ectropis obliqua infestation in Camellia sinensis L.

Insect-induced plant volatile organic compounds (VOCs) may function as either direct defence molecules to deter insects or indirect defence signals to attract the natural enemies of the invading insects. Tea (Camellia sinensis L.), an important leaf-based beverage crop, is mainly infested by Ectropis obliqua which causes the most serious damage. Here, we report a mechanistic investigation of tea plant-derived VOCs in an indirect defence mechanism against E. obliqua. Parasitoid wasp Parapanteles hyposidrae, a natural enemy of E. obliqua, showed strong electrophysiological response and selection behaviour towards S-linalool and β-ocimene, two monoterpenes with elevated emission from E. obliqua-damaged tea plants. Larvae frass of E. obliqua, which also released S-linalool and β-ocimene, was found to attract both mated female or male Pa. hyposidrae according to gas chromatography-electroantennogram detection and Y-tube olfactometer assays. In a field setting, both S-linalool and β-ocimene were effective in recruiting both female and male Pa. hyposidrae wasps. To understand the molecular mechanism of monoterpenes-mediated indirect defence in tea plants, two novel monoterpene synthase genes, CsLIS and CsOCS-SCZ, involved in the biosynthesis of S-linalool or β-ocimene, respectively, were identified and biochemically characterised. When the expression of these two genes in tea plants was inhibited by antisense oligodeoxynucleotide, both volatile emission and attraction of wasps were reduced. Furthermore, gene expression analysis suggested that the expression of CsLIS and CsOCS-SCZ is regulated by the jasmonic acid signalling pathway in the tea plant.

Global boundedness in a Keller-Segel system with nonlinear indirect signal consumption mechanism

<p>In this paper, we study a quasilinear chemotaxis model with a nonlinear indirect consumption mechanism</p><p><disp-formula> <label/> <tex-math id="FE1"> \begin{document}$ \begin{equation*} \left\{ \begin{array}{ll} v_{1t} = \nabla \cdot\big(\psi(v_{1})\nabla v_{1}-\chi \phi(v_{1})\nabla v_{2}\big)+\lambda_{1}v_{1}-\lambda_{2}v_{1}^{\beta},\ &\ \ x\in \Omega, \ t>0,\\[2.5mm] v_{2t} = \Delta v_{2}-w^{\theta}v_{2}, \ &\ \ x\in \Omega, \ t>0,\\[2.5mm] 0 = \Delta w-w+v_{1}^{\alpha}, \ &\ \ x\in \Omega, \ t>0 ,\\[2.5mm] \end{array} \right. \end{equation*} $\end{document} </tex-math></disp-formula></p><p>in a smooth and bounded domain $ \Omega\subset\mathbb{R}^{n}(n\geq 1) $ with homogeneous Neumann boundary conditions, where $ \chi, \; \lambda_{1}, \; \lambda_{2}, \; \theta > 0, \; 0 < \alpha\leq\frac{1}{\theta}, \; \beta\geq 2, \; $ $ \psi $, and $ \phi $ are nonlinear functions that satisfy $ \psi(s)\geq a_{0}(s+1)^{r_{1}} $ and $ 0\leq\phi(s)\leq b_{0}s(s+1)^{r_{2}} $ for all $ s\geq 0 $ with $ a_{0}, b_{0} > 0 $ and $ r_{1}, r_{2}\in \mathbb{R}. $ It has been proven that if $ r_{1} > 2r_{2}+1, $ then the problem admits a global and bounded classical solution for some appropriate nonnegative initial data.</p>

Global boundedness and large time behavior of a two-species competition system with indirect signal consumption

Global boundedness and large time behavior of a two-species competition system with indirect signal consumption

Boundedness and stability for an indirect signal absorption chemotaxis system with signal-dependent motility

Boundedness and stability for an indirect signal absorption chemotaxis system with signal-dependent motility

Global stabilization in a Keller-Segel-growth system with indirect signal production

Global stabilization in a Keller-Segel-growth system with indirect signal production

Global boundedness in a chemotaxis system with signal-dependent motility and indirect signal consumption and logistic source

Global boundedness in a chemotaxis system with signal-dependent motility and indirect signal consumption and logistic source

Analysis of global dynamics in an attraction-repulsion model with nonlinear indirect signal and logistic source

<p>The following chemotaxis system has been considered:</p><p><disp-formula> <label/> <tex-math id="FE1"> \begin{document}$ \begin{equation*} \left\{ \begin{array}{ll} v_{t} = \Delta v-\xi \nabla\cdot(v \nabla w_{1})+\chi \nabla\cdot(v \nabla w_{2})+\lambda v-\mu v^{\kappa},\ &\ \ x\in \Omega, \ t>0,\\[2.5mm] w_{1t} = \Delta w_{1}-w_{1}+w^{\kappa_{1}}, \ 0 = \Delta w-w+v^{\kappa_{2}}, \ &\ \ x\in \Omega, \ t>0,\\[2.5mm] 0 = \Delta w_{2}-w_{2}+v^{\kappa_{3}}, \ &\ \ x\in \Omega, \ t>0 , \end{array} \right. \end{equation*} $\end{document} </tex-math></disp-formula></p><p>under the boundary conditions of $ \frac{\partial{v}}{\partial{\nu}} = \frac{\partial{w_{1}}}{\partial{\nu}} = \frac{\partial{w}}{\partial{\nu}} = \frac{\partial{w_{2}}}{\partial{\nu}} $ on $ \partial \Omega, $ where $ \Omega $ was a bounded smooth domain of $ \mathbb{R}^{n}(n\geq 1), \; \nu $ was the normal vector of $ \partial\Omega, $ and the parameters were $ \lambda, \mu, \xi, \chi, \kappa_{1}, \; \kappa_{2}, \kappa_{3} > 0, $ and $ \kappa > 1. $ In this paper, we showed that if either $ \kappa_{1}\kappa_{2} < \max\{\frac{2}{n}, \kappa_{3}, \kappa-1\} $ or $ \kappa_{1}\kappa_{2} = \max\{\frac{2}{n}, \kappa_{3}, \kappa-1\} $ with the coefficients and initial data satisfying appropriate conditions, then the system possessed a global classical solution. Furthermore, we also have studied the convergence of solutions to a special case of the above system with $ \kappa = \delta+1, \kappa_{1} = 1, \kappa_{2} = \kappa_{3} = \delta $ for $ \delta > 0. $ It has been proven that if $ \mu > 0 $ is large enough, then the corresponding classical solutions exponentially converged to $ ((\frac{\lambda}{\mu})^{\frac{1}{\delta}}, \frac{\lambda}{\mu}, \frac{\lambda}{\mu}, \frac{\lambda}{\mu}), $ where the convergence rate could be formally expressed by the parameters of the system.</p>

How far do indirect signal production mechanisms influence regularity in the three-dimensional Keller–Segel–Navier–Stokes system?

This paper reconsiders the Keller–Segel–Navier–Stokes model with indirect signal production and weak logistic-type degradation in a three-dimensional (3D) bounded and smooth domain. One recent literature has asserted that for all reasonably regular initial data, the associated initial-boundary value problem with certain sub-quadratic degradation possesses at least one global generalized solution which is uniformly bounded and converges to the constant equilibrium in [Formula: see text] with any [Formula: see text]. Nevertheless, the knowledge on regularity properties of solution has not yet exceeded some information on fairly basic integrability features. The present study firstly elevates the regularities of some solution components under the same assumption on degradation exponent, especially establishes the global boundedness in [Formula: see text] with [Formula: see text], and secondly asserts that each of these generalized solutions becomes eventually classical and bounded in [Formula: see text] under some suitably strong sub-quadratic degradation assumption and an explicit smallness condition on the intrinsic growth rate of cells relative to some powers of the degradation coefficient. As a by-product of the latter, these solutions are shown to stabilize toward the corresponding spatially homogeneous state in [Formula: see text]. Our results indeed provide a more in-depth understanding on the global dynamics of solutions, and significantly improve previously known ones. In comparison to the related contributions in the case of direct signal production, our findings inter alia rigorously reveal that the indirect signal production mechanism results in some genuine regularizing effects in the sense that the possibly destabilizing action of chemotactic cross-diffusion in the 3D Keller–Segel–Navier–Stokes system can be greatly weakened or even completely excluded by this indirectness.

Nonlinear transmission exponent for boundedness of solutions to a chemotaxis system with indirect signal production

This paper deals with the Neumann initial–boundary problem for a fully parabolic chemotaxis system with indirect signal production, and the size of phenotypic transmission exponent is identified to guarantee the global existence and boundedness of classical solutions to the problem with suitably regular initial data.

Global dynamics in a chemotaxis system involving nonlinear indirect signal secretion and logistic source

Global dynamics in a chemotaxis system involving nonlinear indirect signal secretion and logistic source

Global boundedness in an attraction-repulsion chemotaxis system involving nonlinear indirect signal mechanism

We study the following chemotaxis system involving nonlinear indirect signal mechanism{ut=Δu−ξ∇⋅(u∇v)+χ∇⋅(u∇z),x∈Ω,t>0,vt=Δv−v+wγ1,x∈Ω,t>0,0=Δw−w+uγ2,x∈Ω,t>0,0=Δz−z+uγ3,x∈Ω, under homogeneous Neumann boundary conditions in a bounded and smooth domain Ω⊂Rn(n≥1), where ξ,χ,γ1,γ2,γ3>0. With the aid of maximum Sobolev regularity and a priori estimates of w and z, it has been proved that if either random diffusion or repulsion mechanism dominates the nonlinear indirect attraction mechanism with γ1γ2<max⁡{2n,γ3}, then the system admits a global classical solution, which is bounded in Ω×(0,∞). Moreover, we also show that under balance situations with γ1γ2=max⁡{2n,γ3}, the existence of global classical solution is determined by the sizes of chemotaxis sensitivity coefficients ξ and χ as well as the initial data u0. This work extends the previous results, where the production of signal is nonlinear mechanism.

Global boundedness and large time behavior in a chemotaxis system with indirect signal consumption

Global boundedness and large time behavior in a chemotaxis system with indirect signal consumption

Source range and depth estimation of propeller cavitation bubble collapse transients in a multipath environment

An experiment is conducted in which a wide aperture array, which is proximate to the sea floor in water 20 m deep, records transits of two motorboats. Occasionally, acoustic transients, which are attributed to collapsing propeller cavitation bubbles, are observed to be superimposed on the continuous broadband radiated noise component of each of the array’s three widely spaced hydrophones. By measuring the time differences of arrival of the transient signals propagating via the direct path at adjacent pairs of hydrophones, passive ranging by wavefront curvature is used to estimate the range and bearing of the transient source. Next, the source depth is estimated by measuring the multipath delay of the surface reflected transient signal. Also, the spectrogram of a single hydrophone’s output is observed to display a Lloyd’s mirror interference pattern due to the direct propagation path of the broadband radiated noise combining with the indirect propagation path signal reflected from the sea floor. The reciprocal of the frequency difference between adjacent destructive interference fringe minima is equal to the multipath time delay. This multipath delay, which equates to the quefrency of the cepstrum’s first rahmonic, contains source range information. The results of the two passive ranging methods are presented.

An Update on Role of Bile Acids in Neurological Functions and Neurodegenerative Diseases: A Narrative Review

Having previously reviewed the role of Bile Acids (BAs) in obesity, NAFLD/NASH/HCC and crosstalk of Gut Microbiome in numerous body disorders here we further attempted to assess part of BAs in normal brain physiology and in different Neurodegenerative Diseases (NDD). BAs constitute significant physiological molecules which apart from modulating nutrient absorption as well as metabolism in peripheral tissues influence neuromodulatory actions in the Central Nervous System (CNS). The formation of bile acids takes place basically from cholesterol in the liver by the canonical as well as alternate pathwaysor in the brain started by the neuron particular sterol Cholesterol-24 hydroxylase (CYP46A1) modulated pathway. Circulating BAs possess the capacity of crossing the Blood Brain Barrier (BBB) and thus gaining entry into the CNS via passive diffusion or through BAs transporters. Brain BAs act in the CNS via activation of membrane or nuclear receptors or influence the working of the neurotransmitter receptors. Indirect signal might be further given to the CNS through the Farsenoid X Receptor (FXR) based Fibroblast growth factor 15/19 (FGF15/19) pathway or the takeda G Protein Coupled (GPC) bile acid receptor 5 (TGR5) based Glucagon Like Peptide 1(GLP) pathway. In case of pathological situations, changes in BAs have been observed to probably aid in the pathogenesis of different neurological diseases. Of greater significance is the supplementationof hydrophilic amidated Ursodeoxycholic Acid (UDCA) or Tauroursodeoxycholic Acid (TUDCA) have been corroborated to illustrate therapeutic advantagesby hampering the neuroinflammatory reactions, apoptosis, Oxidative Stress (OS), Endoplasmic Reticulum (ER) stress, mitochondrial protection or work in the form of probable chaperone for correction of misfolding of proteins in the treatment of different neurological diseases. This yields opportunity of utilization of UDCA along with TUDCA in the treatment of different neurodegenerative diseases inclusive of Alzheimer’s disease; Parkinson’s disease, Huntingtons disease, Amyotrophic Lateral sclerosis, and prion disease.

Global boundedness in a chemotaxis system with signal-dependent motility and indirect signal consumption

This paper deals with the following chemotaxis system ut=Δuγv,x∈Ω,t>0,vt=Δv−vw,x∈Ω,t>0,wt=−δw+u,x∈Ω,t>0,under homogeneous Neumann boundary conditions in a smooth bounded domain Ω⊂Rn (n≤3), where the motility function γ∈C30,+∞ is positive on [0,∞). For all suitably regular initial data, then the corresponding initial boundary value problem possesses a unique global classical solution which is uniformly bounded. The purpose of this work is to remove the smallness assumption on ‖v0‖L∞(Ω) in three dimension (Xu et al., 0000).

Boundedness on a fully parabolic singular chemotaxis system with indirect signal production and logistic source

In this paper, we study the following quasilinear chemotaxis model with singular sensitivity and indirect signal production (0.1)ut=∇⋅(D(u)∇u)−χ∇⋅(uvk∇v)+u(a−bu),t>0,x∈Ω,vt=Δv−v+w,t>0,x∈Ω,wt=Δw−w+u,t>0,x∈Ω,under homogeneous Neumann boundary conditions in a convex smooth bounded domain Ω⊂RN,N≥3, where, χ,a,b>0,k∈(0,12)∪(12,1] and D(u) is smooth function satisfying D(u)≥(u+1)αwithα>0.By constructing suitable Lyapunov functional, we prove that if a>χ24, there exists a positive constant m∗ such that ∫Ωu≥m∗.Based on above result, the lower bound estimates for w and v have been established. When b is large enough and α>max{0,1−4N}, we further prove that the system has a global bounded classical solution. Finally, it is shown that the solution exponentially converges to the constant stationary solution (ab,ab,ab) as t→∞.

A Y-shape-structured electrochemiluminescence biosensor based on carbon quantum dots and locked nucleic acid probe for microRNA determination with single-base resolution

Since microRNAs (miRNAs) are predictors of tumorigenesis, accurate identification and quantification of miRNAs with highly similar sequences are expected to reflect tumor diagnosis and treatment. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor was constructed for miRNAs determination based on Y-shaped junction structure equipped with locked nucleic acids (LNA), graphene oxide-based nanocomposite to enrich luminophores, and conductive matrix. Specifically, two LNA-modified probes were designed for specific miRNA recognition, that is, a dual-amine functionalized hairpin capture probe and a signal probe. A Y-shaped DNA junction structure was generated on the electrode surface upon miRNA hybridizing across the two branches, so as to enhance the selectivity. Carbon quantum dots-polyethylene imine-graphene oxide (CQDs-PEI-GO) nanocomposites were developed to enrich luminophores CQDs, and thus enhancing the ECL intensity. For indirect signal amplification, an electrochemically activated poly(2-aminoterephthalic acid) (ATA) film decorated with gold nanoparticles was prepared on electrode as an effective matrix to accelerate the electron transfer. The fabricated ECL biosensor achieved sensitive determination of miRNA-222 with a limit-of-detection (LOD) as low as 1.95 fM (S/N = 3). Notably, Y-shaped junction structures equipped with LNA probes endowed ECL biosensor with salient single-base discrimination ability and anti-interference capacity. Overall, the proposed Y-shaped ECL biosensor has considerable promise for clinical biomarker determination.

Asymptotic stabilization in a three-dimensional Keller-Segel-Stokes system with indirect signal production and subquadratic degradation

This paper deals with the Keller-Segel-Stokes system with indirect signal production and subquadratic degradation(⋆){nt+u⋅∇n=Δn−χ∇⋅(n∇v)+rn−μnα,vt+u⋅∇v=Δv−v+w,wt+u⋅∇w=Δw−w+n,ut=Δu−∇P+n∇ϕ,∇⋅u=0 in a bounded domain Ω⊂R3 with smooth boundary, where χ>0, r∈R, μ>0, α∈(1,2) and ϕ∈W2,∞(Ω). A recent literature has asserted that for all reasonably regular initial data, the no-flux/no-flux/no-flux/Dirichlet initial-boundary value problem of (⋆) possesses a global bounded classical solution whenever α∈(53,2), but qualitative information on the behavior of solution for such subquadratic degradation cases has never been touched so far. The present study reveals that for the cases r>0 and r=0, such solution exponentially and algebraically approaches the trivial steady state as time goes to infinity, respectively. As for the involved case r>0, it is shown that this solution not only uniformly converges to the spatially homogeneous steady state ((rμ)1α−1,(rμ)1α−1,(rμ)1α−1,0) under an explicit largeness condition on μ, but also exponentially stabilizes toward the corresponding spatially homogeneous steady state under an implicit largeness condition on μ. Our results inter alia provide a more in-depth understanding on the asymptotic behavior of solution to system (⋆), especially explicitly determining the convergence rates for the essentially complicated case of subquadratic degradation.

Implementation of an Adaptive Method for Changing the Frequency Division of the Counter Clock Signal in a Frequency-to-Code Converter

Processing physical quantities into an indirect signal is a standard method of transferring information about the measured quantity to the master system, which analyzes the data obtained from the acquisition system. The intermediate signal is very often the voltage, but another transmission medium can be the frequency of the output signal of the “physical quantity-to-frequency” converter. The article presents the implementation of the adaptive method of selecting the clock signal frequency of the counter working in the converter. The issue of selecting the clock signal frequency for the required processing range of the transducer is discussed in detail. The application of the method using the STM32L476RG microcontroller is presented. The principle of checking the processing range of the developed transducer model is discussed. The algorithms of transducer operation in basic and adaptive modes of measuring the period of the variable frequency signal are proposed. The results of operation, in both modes, of the transducer model of frequency processing are presented, along with the metrological analysis of the results. The influence of selected approximations used to reconstruct the measured quantity on the final presentation of the measurement result is discussed.