Spectral and Rotational Changes in the Isolated Neutron Star RX J0720.4-3125

RX J0720.4-3125 is an isolated neutron star that, uniquely in its class, has shown changes in its thermal X-ray spectrum. We use new spectra taken with Chandra's Low Energy Transmission Grating Spectrometer, as well as archival observations, to try to understand the timescale and nature of these changes. We construct lightcurves, which show both small, slow variations on a timescale of years, and a larger event that occurred more quickly, within half a year. From timing, we find evidence for a `glitch' coincident with this larger event, with a fractional increase in spin frequency of 5x10^{-8}. We compare the `before' and `after' spectra with those from RX J1308.6+2127, an isolated neutron star with similar temperature and magnetic field strength, but with a much stronger absorption feature in its spectrum. We find that the `after' spectrum can be represented remarkably well by the superposition of the `before' spectrum, scaled by two thirds, and the spectrum of RX J1308.6+2127, thus suggesting that the event affected approximately one third of the surface. We speculate the event reflects a change in surface composition caused by, e.g., an accretion episode.Comment: 4 pages, 2 figures, 2 tables, emulateapj format. ApJL, accepte

Origins of Chevron Rollovers in Non-Two-State Protein Folding Kinetics

Chevron rollovers of some proteins imply that their logarithmic folding rates are nonlinear in native stability. This is predicted by lattice and continuum G\=o models to arise from diminished accessibilities of the ground state from transiently populated compact conformations under strongly native conditions. Despite these models' native-centric interactions, the slowdown is due partly to kinetic trapping caused by some of the folding intermediates' nonnative topologies. Notably, simple two-state folding kinetics of small single-domain proteins are not reproduced by common G\=o-like schemes.Comment: 10 pages, 4 Postscript figures (will appear on PRL

Delocalization Transition of a Rough Adsorption-Reaction Interface

We introduce a new kinetic interface model suitable for simulating adsorption-reaction processes which take place preferentially at surface defects such as steps and vacancies. As the average interface velocity is taken to zero, the self- affine interface with Kardar-Parisi-Zhang like scaling behaviour undergoes a delocalization transition with critical exponents that fall into a novel universality class. As the critical point is approached, the interface becomes a multi-valued, multiply connected self-similar fractal set. The scaling behaviour and critical exponents of the relevant correlation functions are determined from Monte Carlo simulations and scaling arguments.Comment: 4 pages with 6 figures, new comment

Interfaces in the returnees' heritage language: Is the complete (re-)activation possible?

Aims and objectives/purpose/research questions: The aim of this study is to examine whether the complete (re-)activation of interface domains in the heritage language (HL) is possible or whether interfaces are likely to preserve features typical for the HL even after many years of residing in the country of origin. Design/methodology/approach: We present the group analysis of direct object marking in Turkish, which is a morphology-syntax-pragmatics interface, of Turkish-German returnees, who returned to Turkey after puberty and have been residing in the country for a minimum of 10 and a maximum of 34 years, and compare them with the control group consisting of Turkish speakers who have been living in Turkey all their lives. Data and analysis: The data were collected using a narrative task, a completion task and a grammaticality judgement task, and analysed both quantitatively and qualitatively. Findings/conclusions: The analysis of the narrative task revealed that the returnee participants used case-marking on direct objects productively depending on the discourse and syntactic position of the direct object in their heritage Turkish. However, their performance on the completion and grammaticality judgement tasks diverged from those of the control group. These findings can be considered as a piece of evidence that interface domains stay obstinate to complete (re-)activation and may preserve features typical for the HL many years after the return to the country of origin. Originality: The study suggests relevance of the Interface Hypothesis to the process of HL (re-)activation. Significance/implications: The study contributes to the research on the HL development of returnees after their return to the country of origin

A Research on the Association between Corporate Governance and Corporate Performance in Turkish Energy Sector

Today’s harsh market conditions prompt companiesto allocate the highest level of emphasis on corporateperformance. However, in some cases interests of managementand shareholders may clash. Subsequently providing investorswith timely, accurate and valid information in today’s everchanging economic environment is vital for transparency. Aim ofthis paper is to measure the association between corporategovernance and corporate performance within companies in theenergy sector listed at Borsa Istanbul (formerly known asIstanbul Stock Exchange)

Hydrodynamic Equations in Quantum Hall Systems at Large Currents

Hydrodynamic equations (HDEQs) are derived which describe spatio-temporal evolutions of the electron temperature and the chemical potential of two-dimensional systems in strong magnetic fields in states with large diagonal resistivity appearing at the breakdown of the quantum Hall effect. The derivation is based on microscopic electronic processes consisting of drift motions in a slowly-fluctuating potential and scattering processes due to electron-electron and electron-phonon interactions. In contrast with the usual HDEQs, one of the derived HDEQs has a term with an energy flux perpendicular to the electric field due to the drift motions in the magnetic field. As an illustration, the current distribution is calculated using the derived HDEQs.Comment: 10 pages, 2 Postscript figures, to be published in J. Phys. Soc. Jpn. 71 (2002) No.

Lms Selection Process For Effective Distance Education System In Organizations

 Towards the end of the 20th century, especially development of science and technology brought some innovation to some conceptual area such as education. In society, to build a quality and civilized life, education emerges as a one of the most important actors. Unfortunately, the rights in education of the every person in society may be delayed due to financial problems, physical disabilities, time pressure, geographical distances or any other reasons. Distance learning is a one of the method that provides education for people by eliminating these disadvantages. Since end of the 19th century, distance education has been provided with some methods such as TV, radio, mail and etc. Especially, in the beginning of 21th century; internet is widely used by everybody. New technological environment has brought a new opportunity for distance education. Learning Management System (LMS) is the most important actor of the internet based distance learning that brings together educators and students for training. LMS allows to deliver materials, having assignment and quizzes and other educational activities. Whether educational institutions or organizations that are emphasis on the training of employees can use LMS platform. Every organization has to decide which LMS is suitable for them. Decision makers face to solve this kind of problems because every LMS has different characteristics and different learning process. This study is focused on choosing suitable LMS for organizations by using AHP methods. Two groups of LMS, open source software’s (Moodle and Sakai) and commercial software’s (BlackBoard and Sharepoint LMS), are compared by using selecting criteria’s. These criteria’s are license costs, flexibility, security, user interface and prevalence of use. In the decision process, different weight ratios are used depending on their priority. The findings of this AHP Process are discussed. Keywords: Distance Learning, LMS, AHP, Decision Making Proces

Hydrodynamic Equation for the Breakdown of the Quantum Hall Effect in a Uniform Current

The hydrodynamic equation for the spatial and temporal evolution of the electron temperature T_e in the breakdown of the quantum Hall effect at even-integer filling factors in a uniform current density j is derived from the Boltzmann-type equation, which takes into account electron-electron and electron-phonon scatterings. The derived equation has a drift term, which is proportional to j and to the first spatial derivative of T_e. Applied to the spatial evolution of T_e in a sample with an abrupt change of the width along the current direction, the equation gives a distinct dependence on the current direction as well as a critical relaxation, in agreement with the recent experiments.Comment: 4 pages, 1 Postscript figure, corrected equations, to be published in J. Phys. Soc. Jpn. 70 (2001) No.