Analysis of planetary evolution with emphasis on differentiation and dynamics

In order to address the early stages of nebula evolution, a three-dimensional collapse code which includes not only hydrodynamics and radiative transfer, but also the effects of ionization and, possibly, magnetic fields is being addressed. As part of the examination of solar system evolution, an N-body code was developed which describes the latter stages of planet formation from the accretion of planetesimals. To test the code for accuracy and run-time efficiency, and to develop a stronger theoretical foundation, problems were studied in orbital dynamics. A regional analysis of the correlation in the gravity and topography fields of Venus was performed in order to determine the small and intermediate scale subsurface structure

Control of electron spin decoherence caused by electron-nuclear spin dynamics in a quantum dot

Control of electron spin decoherence in contact with a mesoscopic bath of many interacting nuclear spins in an InAs quantum dot is studied by solving the coupled quantum dynamics. The nuclear spin bath, because of its bifurcated evolution predicated on the electron spin up or down state, measures the which-state information of the electron spin and hence diminishes its coherence. The many-body dynamics of nuclear spin bath is solved with a pair-correlation approximation. In the relevant timescale, nuclear pair-wise flip-flops, as elementary excitations in the mesoscopic bath, can be mapped into the precession of non-interacting pseudo-spins. Such mapping provides a geometrical picture for understanding the decoherence and for devising control schemes. A close examination of nuclear bath dynamics reveals a wealth of phenomena and new possibilities of controlling the electron spin decoherence. For example, when the electron spin is flipped by a $\pi$-pulse at $\tau$, its coherence will partially recover at $\sqrt{2}\tau$ as a consequence of quantum disentanglement from the mesoscopic bath. In contrast to the re-focusing of inhomogeneously broadened phases by conventional spin-echoes, the disentanglement is realized through shepherding quantum evolution of the bath state via control of the quantum object. A concatenated construction of pulse sequences can eliminate the decoherence with arbitrary accuracy, with the nuclear-nuclear spin interaction strength acting as the controlling small parameter

The Dynamics of the Creation, Evolution, and Disappearance of Terrorist Internet Forums

An examination of the organizational nature of the threat posed by jihadi terrorism, supplying quantitative and qualitative data on the dynamics behind the creation, evolution, and disappearance of the main jihadi Internet forums during the period 2008–2012. An analysis of the origins and functions of the forums, their links with terrorist organizations, their internal structures, and the processes accounting for their stability in cyberspace shows that far from representing a horizontal structure where the main actors are a network of followers, the terrorist presence on the Internet is in fact a hierarchical organization in which intervention by formal terrorist organizations plays a crucial role

A brief overview of the evolution and main features of the biotechnology industry

This paper offers an overview of the origin, evolution and main features of the biotechnology industry, putting particular emphasis on the behaviour of one key actor – the dedicated biotechnology firm. It starts with a brief historical background detailing the origin and dynamics of the industry, which is followed by a more detailed examination of the firms’ strategies, business models and networking behaviour. It concludes with a discussion on the constraints and opportunities faced by firms operating outside the main centres of knowledge production and business in biotechnology, as is the case of dedicated biotechnology firms located in Portugal.FC

A bully in the playground : examining the role of neoliberal economic globalisation in children’s struggle to become ‘fully human’

This article begins by exploring the Western historical progression of the conceptual place of children along a Property-Welfare-Rights continuum. It applies Baxi’s “logics of exclusion and inclusion” to the complex dynamic of children’s advancement in becoming ‘fully human’ through their achievement of internationally recognised human rights. It critically considers the comprehensive vulnerability of children based both on their evolving levels of development and on the multifaceted challenges of the application and enforcement of their rights. The ideological and practical realities influencing this evolution exist in an increasingly globalised world in which international economic dynamics play a particularly influential role. The character and substance of these are explored. This follows with an examination of the influence of these dynamics on both the environment in which the struggle for children’s rights to be recognised takes place, and on the ideological concepts of these rights themselves. It is proposed that the dominant form of globalisation, NEG, perpetuates ideological exclusionary criteria which thwart children’s achievement of becoming “fully human”. This is most evident in the neoliberal views on the paramount importance of the individual, and on the limited role for the state. It is the NEG perception of the child, in locating her/him within an individualistic framework and dismissing the wider societal context, which justifies at best a welfare-entitlement agenda and denies children rights. Further, this results in a justification of the effects of poverty, in particular for children of the South. This exclusion of children from bearing rights is achieved globally through NEG systems and processes which handicap the autonomy of states. The NEG maintains this exclusion of children through its deemed legitimate and commonsensical hegemony. Through these mechanisms, NEG bullies states into advancing a new form of colonialism that discriminates against children. The related way in which human rights discourse has itself been influenced by NEG ideology is also explored. The article concludes with the proposal that the effective recognition of children’s rights necessitates an understanding of the exclusionary criteria imposed by NEG. A fundamental modification of the terms and mechanisms within which NEG functions is essential to compensate for children’s unique and disproportionate vulnerabilities

Assessing a Hydrodynamic Description for Instabilities in Highly Dissipative, Freely Cooling Granular Gases

An intriguing phenomenon displayed by granular flows and predicted by kinetic-theory-based models is the instability known as particle "clustering," which refers to the tendency of dissipative grains to form transient, loose regions of relatively high concentration. In this work, we assess a modified-Sonine approximation recently proposed [Garz\'o et al., Physica A 376, 94 (2007)] for a granular gas via an examination of system stability. In particular, we determine the critical length scale associated with the onset of two types of instabilities -vortices and clusters- via stability analyses of the Navier-Stokes-order hydrodynamic equations by using the expressions of the transport coefficients obtained from both the standard and the modified-Sonine approximations. We examine the impact of both Sonine approximations over a range of solids fraction \phi <0.2 for small restitution coefficients e=0.25--0.4, where the standard and modified theories exhibit discrepancies. The theoretical predictions for the critical length scales are compared to molecular dynamics (MD) simulations, of which a small percentage were not considered due to inelastic collapse. Results show excellent quantitative agreement between MD and the modified-Sonine theory, while the standard theory loses accuracy for this highly dissipative parameter space. The modified theory also remedies a (highdissipation) qualitative mismatch between the standard theory and MD for the instability that forms more readily. Furthermore, the evolution of cluster size is briefly examined via MD, indicating that domain-size clusters may remain stable or halve in size, depending on system parameters.Comment: 4 figures; to be published in Phys. Rev.

Evaluating codon bias perspective in barbiturase gene using multivariate analysis

Barbiturases exist solely in bacteria and encompass an undistinguished protein family. s-Triazine compound introduction into the environment owing to recent industrial practices have revitalized barbiturases. Codon usage patterns were analysed in this study for 17 barbiturase genes encoded by 16 bacterial species. Multivariate and correspondence study of amino acid and codon usage was employed for detecting the cause of variation in the gene content. GC3 of synonymously variable codons, RSCU, NC and CAI were estimated with statistical softwares. Examination of DNA composition along with codon usage was done to reveal dynamics of gene evolution and expression of this enzyme.Keywords: Codon usage, barbiturase gene, multivariate statistical analysisAfrican Journal of Biotechnology, Vol. 13(2), pp. 194-201, 8 January, 201