Comment on: “Epidemic spreading on heterogeneous networks with identical infectivity” [Phys. Lett. A 364 (2007) 189]

In [R. Yang, et al., Phys. Lett. A 364 (2007) 189], it has been introduced a network-based Kermack-McKendrick-like SIR epidemic model, in which each node shows an identical capability of contact A and in which it has been claimed that, on scale free networks, the value A⁻¹ would be a threshold value for the density of recovered individuals. We show here that the recovered individuals cannot follow the claimed threshold behaviour. Furthermore, we give a biologically sound threshold ruling the transitory dynamics of the epidemics.     

Epidemic outbreaks in growing scale-free networks with local structure

The class of generative models has already attracted considerable interest from researchers in recent years and much expanded the original ideas described in BA model. Most of these models assume that only one node per time step joins the network. In this paper, we grow the network by adding n interconnected nodes as a local structure into the network at each time step with each new node emanating m new edges linking the node to the preexisting network by preferential attachment. This successfully generates key features observed in social networks. These include power-law degree distribution p_k∼k^−(3+μ), where μ=(n−1)/m is a tuning parameter defined as the modularity strength of the network, nontrivial clustering, assortative mixing, and modular structure. Moreover, all these features are dependent in a similar way on the parameter μ. We then study the susceptible-infected epidemics on this network with identical infectivity, and find that the initial epidemic behavior is governed by both of the infection scheme and the network structure, especially the modularity strength. The modularity of the network makes the spreading velocity much lower than that of the BA model. On the other hand, increasing the modularity strength will accelerate the propagation velocity.     

Comment on: “Synchronization of two chaotic nonlinear gyros using active control” [Phys. Lett. A 343 (2005) 153]

A modification to the control law presented in [Y. Lei, W. Xu, H. Zheng, Synchronization of two chaotic nonlinear gyros using active control, Phys. Lett. A 343 (2005) 153] is proposed.     

Comment on: “Dynamical analysis of Cohen-Grossberg neural networks with distributed delays” [Phys. Lett. A 364 (2007) 38]

It is pointed out that an unnatural assumption is made in the following Letter [Z. Mao, H. Zhao, Phys. Lett. A 364 (1) (2007) 38]. Therefore, the results of the Letter are not relevant to the real Cohen-Grossberg neural network model.     

Reply to: “Comment on: ‘Efficient high-capacity quantum secret sharing with two-photon entanglement’ [Phys. Lett. A 372 (2008) 1957]” [Phys. Lett. A 373 (2009) 396]

A corresponding Comment, raised by Yang and Wen, claimed that (i) our scheme cannot complete the task of secret sharing well even if the agents obtain the information about their measuring bases; (ii) they give a feasible improvement of our protocol. In this Reply, we show that their first judgment is wrong and their improvement is insecure.     

Erratum to: “Comment on: ‘Electromagnetic wave propagation in single-wall carbon nanotubes’ [Phys. Lett. A 333 (2004) 303]” [Phys. Lett. A 364 (2007) 515]

Here we plot the correct form of Fig. 2 in [H. Khosravi, A. Moradi, Phys. Lett. A 364 (2007) 515].     

Reply to: “Comment on: ‘Effects of including the counterrotating term and virtual photons on the eigenfunctions and eigenvalues of a scalar photon collective emission theory’ [Phys. Lett. A 372 (2008) 2514]” [Phys. Lett. A 372 (2008) 5732]

We compute the emission amplitude for the collective emission from a sphere of identical atoms in the scalar photon theory for both the cases of the complex kernel (i.e. including virtual photons) and real kernel. We explicitly show that the single mode theory based on the real kernel neglects the effects of the different decay rates and frequency shifts associated with the eigenfunctions belonging to the same angular index but with different radial indices. We show that these effects modify, for k₀R?1, both the time dependence of the emission amplitude and its angular distribution, in clear contradiction to the assertions made by the Comment's authors.     

Comment on: “Globally exponential synchronization in array of asymmetric coupled neural networks” [Phys. Lett. A 369 (2007) 444]

In this Letter, we indicate that the proposed sufficient condition in Letter [J.Q. Lu, W.C. Ho, M. Liu, Phys. Lett. A 369 (2007) 444] does not hold when coupling matrix G satisfies Assumption 3 in Letter [J.Q. Lu, W.C. Ho, M. Liu, Phys. Lett. A 369 (2007) 444]. Besides, there are some mistakes in deducing Theorem 1. The mistakes have been corrected and a correct version is given in this Letter.     

Reply to “Comment on ‘Piezonuclear decay of thorium’ [Phys. Lett. A 373 (2009) 1956]” [Phys. Lett. A 374 (2009) 696]

In a Letter appearing in this issue of Physics Letters A, Kowalski raises some critical comments on the experiment [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] that we carried out by cavitating a solution of Thorium-228. The experiment highlighted the anomalous decay of Thorium, thus confirming the results previously obtained by Urutskoev et al. by explosion of titanium foils in solutions. In this Letter, we reply to these comments. We agree with Kowalski that critical comments are one of the key factors of the process to improve the quality of experiments and the interpretation of results. However we do hope that these comments together with the details provided in the replies will promote further and better experiments which are certainly worth performing in order to shed a brighter light on this issue, as Kowalski himself suggests in his comment.     

Reply to “Comment on ‘Piezonuclear decay of thorium’ [Phys. Lett. A 373 (2009) 1956]” [Phys. Lett. A 373 (2009) 3795]

In a paper appearing in this issue of Physics Letters A, Ericsson et al. raise some critical comments on the experiment [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] we carried out by cavitating a solution of thorium-228, which evidenced its anomalous decay behaviour, thus confirming the results previously obtained by Urutskoev et al. by explosion of titanium foils in solutions. In this Letter, we reply to these comments. In our opinion, the main shortcomings of the criticism by the Swedish authors are due to their omitting of inserting our experiment in the wider research stream of piezonuclear reactions, and to the statistical analysis they used, which does not comply with the rules generally accepted for samples with small numbers. However, apart from any possible theoretical speculation, there is the basic fact that two different experiments (ours and that by Urutskoev et al.), carried out independently and by different means, highlight an analogous anomaly in the decay of thorium subjected to pressure waves. Such a convergence of results shows that it is worth to further carry on experimental investigations, in order to get either a confirmation or a disproof of the induced-pressure anomalous behaviour of radioactive nuclides even different from thorium.     

Comment on: “Dynamical analysis of Cohen-Grossberg neural networks with continuously distributed delays” [Phys. Lett. A 364 (2007) 38]

Recently, Mao and Zhao [Z. Mao, H. Zhao, Phys. Lett. A 364 (2007) 38] considered the existence and uniqueness of the equilibrium point of the Cohen-Grossberg neural network model with continuously distributed delays. Mao and Zhao established Theorem 1. In this Letter, we would like to point out that Theorem 1 given by Mao and Zhao is incorrect in general.     

Comment on: “Dense coding and teleportation with one-dimensional cluster states” [Phys. Lett. A 364 (2007) 7]

The schemes on quantum dense coding and teleportation [Phys. Lett. A 364 (2007) 7] are revisited. By reformulizing one-dimensional n-qubit cluster states, we decompose the necessary multi-qubit collective unitary operation into a sequence of single-qubit Hadamard (H) and two-qubit controlled-not (C) operations. Our reduction makes the schemes feasible today.     

Comment on: “Efficient high-capacity quantum secret sharing with two-photon entanglement” [Phys. Lett. A 372 (2008) 1957]

In a recent Letter [F.G. Deng, X.H. Li, H.Y. Zhou, Phys. Lett. A 372 (2008) 1957], an efficient high-capacity quantum secret sharing scheme was proposed. However, in this comment, it is shown that the protocol does not complete the task of secret sharing well when the message sender uses the nonorthogonal entangled states as the quantum information carriers. Finally a feasible improvement of this quantum secret sharing protocol is proposed.     

Reply to “Comment on ‘Contextuality within quantum mechanics manifested in subensemble mean values’ [Phys. Lett. A 373 (2009) 3430]” [Phys. Lett. A 374 (2010) 1397]

In this reply, we point out that the claim by De Zela (2010) [2] is unjustified because the setup he discusses is not equivalent to the setup analysed in our paper (Pan and Home (2009) [1]). Hence his subsequent argument claiming the reproducibility of our demonstrated quantum effect of path-spin contextuality by the Kochen-Specker realist model is not relevant.     

Reply to “Comment on: ‘Questions concerning the generalized Hartman effect’ [Phys. Lett. A 375 (2011) 3259]”

Some questions on the generalized Hartman effect presented by Kudaka and Matsumoto [S. Kudaka, S. Matsumoto, Phys. Lett. A 375 (2011) 3259] and a comment on them given by Milanovi? and Radovanovi? are discussed.     

Reply to: “Comment on: ‘From classical to modern ether-drift experiments: the narrow window for a preferred frame’ [Phys. Lett. A 333 (2004) 355]” [Phys. Lett A 361 (2007) 509]

We present some arguments that should induce to re-consider from a new perspective the interference experiments in moving media (Michelson–Morley, Fizeau, …). These considerations are useful to understand and appreciate the experimental test recently proposed by Guerra and de Abreu.