Species Abundance Patterns in Complex Evolutionary Dynamics

An analytic theory of species abundance patterns (SAPs) in biological networks is presented. The theory is based on multispecies replicator dynamics equivalent to the Lotka-Volterra equation, with diverse interspecies interactions. Various SAPs observed in nature are derived from a single parameter. The abundance distribution is formed like a widely observed left-skewed lognormal distribution. As the model has a general form, the result can be applied to similar patterns in other complex biological networks, e.g. gene expression.Comment: 4 pages, 3 figures. Physical Review Letters, in pres

Instability of spatial patterns and its ambiguous impact on species diversity

Self-arrangement of individuals into spatial patterns often accompanies and promotes species diversity in ecological systems. Here, we investigate pattern formation arising from cyclic dominance of three species, operating near a bifurcation point. In its vicinity, an Eckhaus instability occurs, leading to convectively unstable "blurred" patterns. At the bifurcation point, stochastic effects dominate and induce counterintuitive effects on diversity: Large patterns, emerging for medium values of individuals' mobility, lead to rapid species extinction, while small patterns (low mobility) promote diversity, and high mobilities render spatial structures irrelevant. We provide a quantitative analysis of these phenomena, employing a complex Ginzburg-Landau equation.Comment: 4 pages, 3 figures and supplementary information. To appear in Phys. Rev. Lett

The impact of the populace on government of the city of Rome in the fourth century A.D

The purpose of this study is to show how popular rioting and fear of popular rioting and unrest came to be such a major concern of the Prefect of the City and his subordinates during the fourth century, a period when Emperors no longer lived at Rome (and so did net have to fear for their personal safety, when Plebeians were rioting in Rome), and in the early years of which the Praetorian Guard, the only force in Rome capable of crushing popular riots by brute force, was disbanded. The first chapter deals with the status of Rome in the fourth century. It was no longer the political centre of the Empire, but it seems to have been the centre of patriotic feeling more than ever before, which is perhaps why Emperors were less harsh to the plebeians when they rioted than to provincials, and is why they took pains to help the Prefect of the City in dealing with plebeian grievances. Chapter 2 deals with the discomforts of living in Rome, and subsisting there on the one hand, and the compensations, the bread and circuses, on the other. The third chapter deals with the causes of disturbances at Rome, and how typical of the metropolises of the Empire (Rome, Alexandria, Antioch, Carthage and Constantinople) were the causes of riots, and their level of violence. Fourth century Rome is also compared to Rome in the Severan period to see how much or little it had changed. Chapter 4 concerns the short term solutions to disturbances that is the immediate options available to and adopted by the authorities once the disturbance had started. Chapter 5 deals with the laws passed by Emperors to ensure that the people got their bread and circuses, and with other areas in which Emperors concerned themselves, such as the provision of a rudimentary health service

Kontestasi Pemikiran Dasar Negara dalam Perwujudan Hukum di Indonesia

Pembentukan dasar negara menempati proses penting dalam sejarah kebangsaan.Dari sinilah kita dapat melihat negara ini mau dibawa ke mana oleh founding fathers. Saatmenilik proses kesejarahan panjang itu, tergambar bahwa kontestasi pemikiran pembentukandasar negara tidaklah sederhana. Para tokoh mencoba merebut simpati dan adu gagasan.“Pertaruangan” ide dan gagasan inilah yang menjadikan produk pemikiran dasar negarasenantisa dinamis hingga saat ini. Apalagi dalam perbincangan negara berdasar Pancasilaatau berdasarkan Islam. Peran tokoh nasionalis Islam sangat penting dalam Perumusan dasarnegara Indonesia. Terutama pada penghapusan kata-kata yang kurang berkenan pada butirpertama Piagam Jakarta, hal ini tidak lantas dipandang sebagai suatu kekalahan politik umatIslam. Sebaliknya hal ini harus dipandang sebagai sebuah sikap inklusif umat Islam yanghendak dikembangkan demi mewujudkan prinsip Islam sebagai suatu ajaran yang lebihmementingkan kemaslahatan bersama

Secondary literacy across the curriculum: Challenges and possibilities

This paper discusses the challenges and possibilities attendant upon successfully implementing literacy across the curriculum initiatives – or ‘school language policies’ as they have come to be known - particularly at the secondary or high school level. It provides a theoretical background to these issues, exploring previous academic discussions of school language policies, and highlights key areas of concern as well as opportunity with respect to school implementation of such policies. As such, it provides a necessary conceptual background to the subsequent papers in this special issue, which focus upon the Secondary Schools’ Literacy Initiative (SSLI) – a New Zealand funded programme that aims to establish cross-curricular language and literacy policies in secondary schools

Clustering in complex networks. II. Percolation properties

The percolation properties of clustered networks are analyzed in detail. In the case of weak clustering, we present an analytical approach that allows to find the critical threshold and the size of the giant component. Numerical simulations confirm the accuracy of our results. In more general terms, we show that weak clustering hinders the onset of the giant component whereas strong clustering favors its appearance. This is a direct consequence of the differences in the $k$-core structure of the networks, which are found to be totally different depending on the level of clustering. An empirical analysis of a real social network confirms our predictions.Comment: Updated reference lis

The application of semiconductors to quasi- optical isolators for use at submillimeter wavelengths

Semiconductor application to quasi-optical isolators - nonreciprocal reflection beam isolator and far infrared isolators using Faraday rotatio

The Clumping Transition in Niche Competition: a Robust Critical Phenomenon

We show analytically and numerically that the appearance of lumps and gaps in the distribution of n competing species along a niche axis is a robust phenomenon whenever the finiteness of the niche space is taken into account. In this case depending if the niche width of the species $\sigma$ is above or below a threshold $\sigma_c$, which for large n coincides with 2/n, there are two different regimes. For $\sigma > sigma_c$ the lumpy pattern emerges directly from the dominant eigenvector of the competition matrix because its corresponding eigenvalue becomes negative. For $\sigma </- sigma_c$ the lumpy pattern disappears. Furthermore, this clumping transition exhibits critical slowing down as $\sigma$ is approached from above. We also find that the number of lumps of species vs. $\sigma$ displays a stair-step structure. The positions of these steps are distributed according to a power-law. It is thus straightforward to predict the number of groups that can be packed along a niche axis and it coincides with field measurements for a wide range of the model parameters.Comment: 16 pages, 7 figures; http://iopscience.iop.org/1742-5468/2010/05/P0500