Multiple Humps Research Articles

Hormetic and synergistic effects of cancer treatments revealed by modelling combinations of radio - or chemotherapy with immunotherapy

BackgroundRadio/chemotherapy and immune systems provide examples of hormesis, as tumours can be stimulated (or reduced) at low radio/chemical or antibody doses but inhibited (or stimulated) by high doses.MethodsInteractions between effector cells, tumour cells and cytokines with pulsed radio/chemo-immunotherapy were modelled using a pulse differential system.ResultsOur results show that radio/chemotherapy (dose) response curves (RCRC) and/or immune response curves (IRC) or a combination of both, undergo homeostatic changes or catastrophic shifts revealing hormesis in many parameter regions. Some mixed response curves had multiple humps, posing challenges for interpretation of clinical trials and experimental design, due to a fuzzy region between an hormetic zone and the toxic threshold. Mixed response curves from two parameter bifurcation analyses demonstrated that low-dose radio/chemotherapy and strong immunotherapy counteract side-effects of radio/chemotherapy on effector cells and cytokines and stimulate effects of immunotherapy on tumour growth. The implications for clinical applications were confirmed by good fits to our model of RCRC and IRC data.ConclusionsThe combination of low-dose radio/chemotherapy and high-dose immunotherapy is very effective for many solid tumours. The net benefit and synergistic effect of combined therapy is conducive to the treatment and inhibition of tumour cells.

Identification of Concurrent Clear-Air and Precipitation Doppler Profiles for VHF Radar and an Incorporating Study of Strongly Convective Precipitation with Dual-Polarized Microwave Radiometer

Two approaches were designed to identify the echoes of clear air and precipitation when both coexist in the very-high-frequency (VHF) radar spectra: contour-based and peak-finding methods. The contour-based approach was used to model a 2D Doppler spectra to determine the locations of multiple spectral humps, and the peak-finding approach was used to find the spectral peaks on request. Grouping, sifting, and Gaussian fitting were performed further for such obtained contour centres and spectral peaks to yield Doppler velocities and spectral widths. In general, the two approaches resulted in corresponding outcomes and can be complementary to find the spectral peaks as fully as possible. The Doppler velocities retrieved from the two approaches were cooperatively used to develop an effective process of Doppler profiling for treating a great amount of radar data, which was validated with the radar data collected during a rainy and strongly convective atmosphere. As an application of Doppler profiling results, the hydrometeor parameters measured by a dual-polarized microwave radiometer were investigated jointly with radar observation, showing that a strong updraft air could bring the liquid water to a height above the melting layer and then the Bergeron effect and coalescence processes on formation of ice crystals and graupel particles occur accordingly.

Numerical study of the Kelvin-Helmholtz instability and its effect on synthetic emission from magnetized jets

Context.Nonthermal emission from active galactic nucleus (AGN) jets extends up to large scales, even though they are prone to many magnetohydrodynamic instabilities.Aims.The main focus of this study is to understand the effect of magnetohydrodynamic instabilities on the nonthermal emission from large-scale AGN jets.Methods.We performed high-resolution three-dimensional numerical magnetohydrodynamic simulations of a plasma column to investigate the dynamical and emission properties of jet configurations at kiloparsec scales with different magnetic field profiles, jet speeds, and density contrast. We also obtained synthetic nonthermal emission signatures for different viewing angles using an approach that assumes static particle spectra and that is obtained by evolving the particle spectra using Lagrangian macroparticles incorporating the effects of shock acceleration and radiative losses.Results.We find that shocks due to the Kelvin-Helmholtz (KH) instability in the axial magnetic field configurations can strongly affect the jet dynamics. Additionally, we also find weak biconical shocks in the underdense jet columns. The helical magnetic field hinders the vortex growth at the shear surface and thereby stabilizes the jet column. With the evolving particle spectra approach, the synthetic spectral energy distributions obtained for cases with strong KH instability show multiple humps ranging from the radio to the TeV gamma-ray band.Conclusions.We conclude that high-energy electrons that are accelerated in the vicinity of freshly formed shocks due to KH instability result in high X-ray emission.

NGA-Inspired Nanorobots-Assisted Detection of Multifocal Cancer.

We propose a new framework of computing-inspired multifocal cancer detection procedure (MCDP). Under the rubric of MCDP, the tumor foci to be detected are regarded as solutions of the objective function, the tissue region around the cancer areas represents the parameter space, and the nanorobots loaded with contrast medium molecules for cancer detection correspond to the optimization agents. The process that the nanorobots detect tumors by swimming in the high-risk tissue region can be regarded as the process that the agents search for the solutions of an objective function in the parameter space with some constraints. For multimodal optimization (MMO) aiming to locate multiple optimal solutions in a single simulation run, the niche technology has been widely used. Specifically, the niche genetic algorithm (NGA) has been shown to be particularly effective in solving MMO. It can be used to identify the global optima of multiple hump functions in a running, effectively keep the diversity of the population, and prematurely avoid the genetic algorithm. Learning from the optimization procedure of NGA, we propose the NGA-inspired MCDP in order to locate the tumor targets efficiently while taking into account realistic in vivo propagation and controlling of nanorobots, which is different from the use scenario of the standard NGA. To improve the performance of the MCDP, we also modify the crossover operator of the original NGA from crossing within a population to crossing between two populations. Finally, we present comprehensive numerical examples to demonstrate the effectiveness of the NGA-inspired MCDP when the biological objective function is associated with the blood flow velocity profile caused by tumor-induced angiogenesis.

Onboard satellite visibility prediction using metamodeling based framework

Satellite autonomous systems are employed to address complex space applications through onboard data processing and mission planning. To take advantage of onboard autonomous systems, rapid onboard satellite visibility predictions are necessary for certain decision-making missions, including Earth observation resource allocation and satellite data transmission. We consider this visibility prediction process as a roots-finding problem for a multiple hump function, and design a metamodeling-based framework with a self-adaptive interpolation method. Metamodels are developed as surrogates for visibility prediction functions to reduce expensive computational costs. Our proposed framework has a broad range of applications for all orbital types and orbit propagators. We conduct the experiments using different metamodeling techniques, radial basis functions, Kriging, and support vector regression based upon real China's satellites. Numerical simulations indicate that the proposed framework outperforms existing interpolation methods, efficiently reducing the onboard computational cost.

Intense keV IAP generation by orthogonally polarized multicycle midinfrared two-color laser fields

We theoretically investigate the generation of intense keV attosecond pulses in an orthogonally polarized multicycle midinfrared two-color laser field. It is demonstrated that multiple continuum-like humps, which have a spectral width of about twenty orders of harmonics and an intensity of about one order higher than adjacent normal harmonic peaks, are generated under proper two-color delays, owing to the reduction of the number of electron-ion recollisions and suppression of inter-half-cycle interference effect of multiple electron trajectories when the long wavelength midinfrared driving field is used. Using the semiclassical trajectory model, we have revealed the two-dimensional manipulation of the electron-ion recollision process, which agrees well with the time frequency analysis. By filtering these humps, intense isolated attosecond pulses are directly generated without any phase compensation. Our proposal provides a simple technique to generate intense isolated attosecond pulses with various central photon energies covering the multi-keV spectral regime by using multicycle driving pulses with high pump energy in experiment.

Displacement back analysis for underground engineering based on immunized continuous ant colony optimization

The objective function of displacement back analysis for rock parameters in underground engineering is a very complicated nonlinear multiple hump function. The global optimization method can solve this problem very well. However, many numerical simulations must be performed during the optimization process, which is very time consuming. Therefore, it is important to improve the computational efficiency of optimization back analysis. To improve optimization back analysis, a new global optimization, immunized continuous ant colony optimization, is proposed. This is an improved continuous ant colony optimization using the basic principles of an artificial immune system and evolutionary algorithm. Based on this new global optimization, a new displacement optimization back analysis for rock parameters is proposed. The computational performance of the new back analysis is verified through a numerical example and a real engineering example. The results show that this new method can be used to obtain suitable parameters of rock mass with higher accuracy and less effort than previous methods. Moreover, the new back analysis is very robust.

Calibrating probability distributions with convex-concave-convex functions: application to CDO pricing

This paper considers a class of functions referred to as convex-concave-convex (CCC) functions to calibrate unimodal or multimodal probability distributions. In discrete case, this class of functions can be expressed by a system of linear constraints and incorporated into an optimization problem. We use CCC functions for calibrating a risk-neutral probability distribution of obligors default intensities (hazard rates) in collateral debt obligations (CDO). The optimal distribution is calculated by maximizing the entropy function with no-arbitrage constraints given by bid and ask prices of CDO tranches. Such distribution reflects the views of market participants on the future market environments. We provide an explanation of why CCC functions may be applicable for capturing a non-data information about the considered distribution. The numerical experiments conducted on market quotes for the iTraxx index with different maturities and starting dates support our ideas and demonstrate that the proposed approach has stable performance. Distribution generalizations with multiple humps and their applications in credit risk are also discussed.

A Study of Genetic Algorithm Based on Niche Technique

Compared to simple genetic algorithm which has a disadvantage of slow speed in early and later convergence, genetic algorithm which is based on niche technique and keeping the diversity of individuals, helps prevent prematurity and shows a better performance. The paper tries to solve the problem of multiple hump function optimization based on niche genetic algorithm. The simulation results show that the niche genetic algorithm can maintain the relative stability of diversity of individuals in the evolution process, speeding up the rate of convergence to a large extent.

Dynamics of a thin viscoelastic film on an inclined plane

A theory for two-dimensional long and stationary waves of finite-amplitude on a thin viscoelastic fluid (weakly elastic) layer flowing down an inclined plane is investigated. A set of exact averaged equations for the viscoelastic film flow system is described and linearised stability analysis of the uniform flow is performed using normal-mode formulation and the critical condition for linear instability is obtained. The linearised instability for the permanent wave equation, consistent to the second order in ϵ ( ϵ = h ¯ 0 / L , h ¯ 0 – unperturbed film thickness, L – characteristic length) is examined and the eigenvalue properties of the fixed points are classified in various parametric regimes. The possible domains of heteroclinic orbits and the regions of possible nonlinear bifurcations are analysed for different values of viscoelastic parameter Γ. Numerical integration of the permanent wave equation as a third order dynamical system is carried out. While wave transitions in real life involve complex spatio-temporal dynamics and many of these transitions lead to chaotic waves that are not stationary traveling waves, bifurcation of stationary traveling waves has been examined as a preliminary study of the more complex transitions. Different bifurcation scenarios leading to multiple hump solitary waves or leading to chaos are exhibited in the parametric space. The results are compared and contrasted with the Newtonian results. A summary of the bifurcation scenarios in the We versus cot θ/ Re plane is obtained for different values of viscoelastic parameter Γ, when Re ≈ 13.33 and Re = 100.

A linear filter approximation to the hammer/string interaction for use in a commuted synthesis piano model

In commuted synthesis of string instruments, the soundboard/body resonator is commuted to the excitation point and replaced by its own impulse response [Smith and Van Duyne, elsewhere in this session]. Hence, the highly nonlinear hammer/string interaction must be replaced by a commutable linear filter. Using the wave digital hammer computational model of the piano hammer [ 3300(A) (1994)], it was observed that the force pulse of a hammer striking an infinite string was qualitatively similar to the impulse response of a second-order filter with two real poles. Hence, good second- and higher-order filter designs based on physical data were possible. However, multiple humps may appear in the hammer force pulse on a terminated string due to returning string waves. It was observed that the magnitude spectra of the single hump spectrum and the multiple hump spectrum were similar in bandwidth, differing only in a slight ringing in the lower spectrum due to the lowpassed combing effect of the returning string waves. Therefore, an equalization filter was designed to summarize this combing effect by fitting a bank of parallel second-order sections to the complex ratio spectrum. Excellent linear piano hammer simulations were produced.

Acoustooptic spectrum analyzer: detection of pulsed signals

This paper describes the temporal response of an acoustooptic spectrum analyzer to pulse-modulated cw signals. The detected waveforms from a real-time photodetector array are analyzed as a function of pulse width, weighting function parameters, and relative photodetector to spectral centroid location. The input pulse envelope is modified in the forms of signal duration stretching, the appearance of a flattop, multiple humps, and longer rise and fall times. Various schemes are discussed on the determination of the pulse width from the detected waveform.

Stochastic analysis of explosive behaviour: A qualitative approach

In many instances, the evolution of physico-chemical systems involves a long slow induction period followed by an abrupt switching to a final stable attractor. In the present paper the properties of fluctuations during this explosive stage of evolution are analyzed. Qualitative arguments, confirmed by an exactly soluble model, establish that this regime is characterized by the development of long tails and multiple humps in the probability distribution. The implications of this phenomenon of transient bimodality are discussed.

Transient evolution towards a unique stable state: Stochastic analysis of explosive behavior in a chemical system

A stochastic description of an isothermal chemical system showing explosive behavior is developed. Numerical analysis shows the appearance of multiple humps of the probability distribution. This implies the onset of chaotic behavior reflecting the random character of the ignition process. Various characteristics of the phenomenon, such as onset time and duration, are studied in terms of the size of the system, the intrinsic parameters, and initial conditions. The implications of the results in combustion are discussed.

Stochastic theory of adiabatic explosion

A stochastic description of an exothermic reaction leading to adiabatic explosion is set up. The numerical solution of the master equation reveals the appearance of a long tail and of multiple humps of the probability distribution, which subsist for a certain period of time. During this interval the system displays a markedly chaotic behavior, reflecting the random character of the ignition process. An analytical description of this transient evolution is developed, using a piecewise linear approximation of the transition rates. A comparison with other transient phenomena observed in stochastic theory is carried out.

Angiocardiography. Assessment of the Procedure

It is our feeling that the emphasis on the diagnosis of cardiac malformations is misplaced and that the emphasis should be primarily on angiocardiography with physiologic See Images in the PDF File determinations kept at a minimum and used selectively to point up the physiologic abnormalities that relate directly to the abnormal anatomy visualized by angiocardiography. We further believe that all phases of the angiocardiographic segment of cardiac diagnosis properly belong in the hands of the trained cardiovascular radiologist. During the past four years in our institution, this approach has been effective. The primary emphasis is on angiocardiography and only a minimal amount of physiologic data is obtained, primarily pressure studies. In many cases of cyanotic heart disease, the entire evaluation can be made on the basis of angiocardiography. Physiologic studies are, in our opinion, often irrelevant. It is also extremely important in young infants with cyanotic heart disease that the diagnostic procedure be short and precise, and prolonged procedures, in order to gather yards of paper with multiple humps, curves and wiggly lines is, in a practical sense, unnecessary and inadvisable.