concentration parameter
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2021 ◽  
Vol 136 (11) ◽  
Author(s):  
Irina Bashkirtseva ◽  
Lev Ryashko ◽  
Jorge Duarte ◽  
Jesús M. Seoane ◽  
Miguel A. F. Sanjuan

AbstractDynamical systems modeling tumor growth have been investigated to analyze the dynamics between tumor and healthy cells. Recent theoretical studies indicate that these interactions may lead to different dynamical outcomes under the effect of particular cancer therapies. In the present paper, we derive a system of nonlinear differential equations, in order to investigate solid tumors in vivo, taking into account the impact of chemotherapy on both tumor and healthy cells. We start by studying our model only in terms of deterministic dynamics under the variation of a drug concentration parameter. Later, with the introduction of noise, a stochastic model is used to analyze the impact of the unavoidable random fluctuations. As a result, new insights into noise-induced transitions are provided and illustrated in detail using techniques from dynamical systems and from the theory of stochastic processes.


2021 ◽  
Vol 54 (3) ◽  
pp. 453-460
Author(s):  
Phat Nguyen Huu ◽  
Hoan Nguyen Duc

The underwater environmental monitoring system applying IoT is now developing for 4.0 industry. It helps not only to simplify work but also to increase efficiency and reduce costs and execution time as well as ensure health to avoid contact with toxic solutions. In this paper, we first model the process of measuring NH3 concentration manually to automate. Secondly, the proposed model is combined with the process of processing output image automatically and displaying the results on the server. Thirdly, the system is able to measure the concentration by VNC viewer connecting with Raspberry pi4 via WiFi. The result of the NH3 concentration parameter is sent to users quickly to alert promptly when it reaches a dangerous threshold. Experiments show that the system not only ensures fast processing time (less than 5 minutes) but also improves accuracy (up to 80%) comparing with real devices.


2021 ◽  
Vol 496 (1) ◽  
pp. 80-85
Author(s):  
L. R. Botvina ◽  
A. D. Zavyalov ◽  
I. O. Sinev

2020 ◽  
Vol 498 (4) ◽  
pp. 5916-5935
Author(s):  
Denis Tramonte ◽  
Yin-Zhe Ma

ABSTRACT We detect the neutral hydrogen (H i) radial brightness temperature profile in large-scale haloes by stacking 48 430 galaxies selected from the 2dFGRS catalogue on to a set of 21-cm intensity maps obtained with the Parkes radio telescope, spanning a total area of ∼1300 deg2 on the sky and covering the redshift range 0.06 ≲ z ≲ 0.10. Maps are obtained by removing both 10 and 20 foreground modes in the principal component analysis. We perform the stack at the map level and extract the profile from a circularly symmetrized version of the halo emission. We detect the H i halo emission with the significance 12.5σ for the 10-mode and 13.5σ for the 20-mode removed maps at the profile peak. We jointly fit for the observed halo mass Mv and the normalization $c_{0,\rm H\, \small{I}}$ for the H i concentration parameter against the reconstructed profiles, using functional forms for the H i halo abundance proposed in the literature. We find $\log _{10}{(M_{\rm v}/\text{M}_{\odot })}= 16.1^{+0.1}_{-0.2}$, $c_{0,\rm H\, \small{I}}=3.5^{+0.7}_{-1.0}$ for the 10-mode and $\log _{10}{(M_{\rm v}/\text{M}_{\odot })}= 16.5^{+0.1}_{-0.2}$, $c_{0,\rm H\, \small{I}}=5.3^{+1.1}_{-1.7}$ for the 20-mode removed maps. These estimates show the detection of the integrated contribution from multiple galaxies located inside very massive haloes. We also consider subsamples of 13 979 central and 34 361 satellite 2dF galaxies separately, and obtain marginal differences suggesting satellite galaxies are H i-richer. This work shows for the first time the feasibility of testing theoretical models for the H i halo content directly on profiles extracted from 21-cm maps and opens future possibilities for exploiting upcoming H i intensity-mapping data.


2020 ◽  
Vol 499 (2) ◽  
pp. 2912-2933
Author(s):  
Jonathan Freundlich ◽  
Fangzhou Jiang ◽  
Avishai Dekel ◽  
Nicolas Cornuault ◽  
Omry Ginzburg ◽  
...  

ABSTRACT We explore a function with two shape parameters for the dark-matter halo density profile subject to baryonic effects, which is a special case of the general Zhao family of models applied to simulated dark-matter haloes by Dekel et al. This profile has variable inner slope and concentration parameter, and analytic expressions for the gravitational potential, velocity dispersion, and lensing properties. Using the Numerical Investigation of a Hundred Astrophysical Objects cosmological simulations, we find that it provides better fits than the Einasto profile and the generalized NFW profile with variable inner slope, in particular towards the halo centres. We show that the profile parameters are correlated with the stellar-to-halo mass ratio Mstar/Mvir. This defines a mass-dependent density profile describing the average dark-matter profiles in all galaxies, which can be directly applied to observed rotation curves of galaxies, gravitational lenses, and semi-analytic models of galaxy formation or satellite–galaxy evolution. The effect of baryons manifests itself by a significant flattening of the inner density slope and a 20 per cent decrease of the concentration parameter for Mstar/Mvir = 10−3.5–10−2, corresponding to $M_{\rm star} \!\sim \! 10^{7-10}\, \mathrm{ M}_\odot$. The accuracy by which this profile fits simulated galaxies is similar to certain multiparameter mass-dependent profiles, but its fewer parameters and analytic nature make it most desirable for many purposes.


2020 ◽  
Vol 498 (3) ◽  
pp. 4450-4464
Author(s):  
Kuan Wang ◽  
Yao-Yuan Mao ◽  
Andrew R Zentner ◽  
Johannes U Lange ◽  
Frank C van den Bosch ◽  
...  

ABSTRACT The concentration parameter is a key characteristic of a dark matter halo that conveniently connects the halo’s present-day structure with its assembly history. Using ‘Dark Sky’, a suite of cosmological N-body simulations, we investigate how halo concentration evolves with time and emerges from the mass assembly history. We also explore the origin of the scatter in the relation between concentration and assembly history. We show that the evolution of halo concentration has two primary modes: (1) smooth increase due to pseudo-evolution; and (2) intense responses to physical merger events. Merger events induce lasting and substantial changes in halo structures, and we observe a universal response in the concentration parameter. We argue that merger events are a major contributor to the uncertainty in halo concentration at fixed halo mass and formation time. In fact, even haloes that are typically classified as having quiescent formation histories experience multiple minor mergers. These minor mergers drive small deviations from pseudo-evolution, which cause fluctuations in the concentration parameters and result in effectively irreducible scatter in the relation between concentration and assembly history. Hence, caution should be taken when using present-day halo concentration parameter as a proxy for the halo assembly history, especially if the recent merger history is unknown.


Author(s):  
Fatin Najihah Badarisam ◽  
Adzhar Rambli ◽  
Mohammad Illyas Sidik

<span>This paper focuses on comparing two discordancy tests between robust and non-robust statistic to detect a single outlier in univariate circular data. So far, to the best author knowledge that there is no literature make a comparison between both tests of <em>RCDu Statistic</em> and </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span>. The test statistics are based on the circular median and spacing theory. In addition, those statistics can detect multiple and patches outliers. The performance tests of <em>RCDu Statistic</em> and </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span> are tested in outlier proportion of correct detection, masking and swamping effect. At the beginning stage, we obtained the cut-off points for the <em>RCDu Statistic</em> and </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span> by applying Monte Carlo simulation studies. Then, generated sample from von Mises (VM) with the combination of sample size and concentration parameter. The estimating process of cut-off points for both statistics is repeated 3000 times at 10%, 5% and 1% upper percentiles. As a result, the <em>RCDu Statistic</em> perform well in detecting a correct single outlier. Moreover, the <em>RCDu Statistic</em> has a lower masking rate compared to </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span>.  However, the </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span> is better than <em>RCDu Statistic</em> for swamping effect due to a lower swamping rate. Thus, <em>RCDu Statistic</em> performs better than </span><em><span>𝐺</span><sub><span>1</span></sub><span> Statistic</span></em><span> in detecting a single outlier for von Mises (VM) sample. As an illustration, both statistics were applied to the real data set from a conducted experiments series to investigate the northen cricket frogs homing ability.</span>


2020 ◽  
pp. 1-7
Author(s):  
Nor Hafizah Moslim ◽  
Yong Zulina Zubairi ◽  
Abdul Ghapor Hussin ◽  
Siti Fatimah Hassan ◽  
Nurkhairany Amyra Mokhtar

Bootstrap method is a computer-based technique for making certain kind of statistical inferences which can simplify the often intricate calculations of traditional statistical theory. Recently, bootstrapping has been widely used for the parameter estimation of linear data. In this paper, we consider bootstrapping methods in the construction of the confidence interval of concentration parameter, for the von Mises distribution. The performances of confidence interval based on percentile bootstrap, bootstrap-t and calibration bootstrap are evaluated via simulation study. The numerical results found that confidence interval based on the calibration bootstrap is good in terms of coverage probability. Meanwhile, confidence interval based on the bootstrap-t method has a shorter expected length. The confidence intervals were illustrated using daily wind direction data recorded at maximum wind speed for four stations in Malaysia. From point estimates of the concentration parameter and the respective confidence interval, we note that the method works well for a wide range of values. The implication of the study is that confidence interval of the concentration parameter can be obtained using bootstrap as it provides good estimates. Keywords: bootstrap-t; calibration bootstrap; concentration parameter; percentile bootstrap; von Mises distribution


2019 ◽  
Vol 488 (2) ◽  
pp. 1635-1651 ◽  
Author(s):  
M S Angelo ◽  
A E Piatti ◽  
W S Dias ◽  
F F S Maia

Abstract The study of dynamical properties of Galactic open clusters (OCs) is a fundamental prerequisite for the comprehension of their dissolution processes. In this work, we characterized 12 OCs, namely: Collinder 258, NGC 6756, Czernik 37, NGC 5381, Ruprecht 111, Ruprecht 102, NGC 6249, Basel 5, Ruprecht 97, Trumpler 25, ESO 129−SC32, and BH 150, projected against dense stellar fields. In order to do that, we employed Washington CT1 photometry and Gaia DR2 astrometry, combined with a decontamination algorithm applied to the three-dimensional astrometric space of proper motions and parallaxes. From the derived membership likelihoods, we built decontaminated colour–magnitude diagrams, while structural parameters were obtained from King profiles fitting. Our analysis revealed that they are relatively young OCs (log(t  yr−1) ∼7.3–8.6), placed along the Sagittarius spiral arm, and at different internal dynamical stages. We found that the half-light radius to Jacobi radius ratio, the concentration parameter and the age to relaxation time ratio describe satisfactorily their different stages of dynamical evolution. Those relative more dynamically evolved OCs have apparently experienced more important low-mass star loss.


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