Curie Temperature for Small World Ising Systems of Different Dimensions

For Small World Ising systems of different dimensions, "concentration" dependencies T_C(p) of the Curie temperature upon the fraction p of long-range links have been derived on a basis of simple physical considerations. We have found T_C(p) ~ 1/ln|p| for 1D, T_C(p) ~ p^{1/2} for 2D, and T_C(p) ~ p^{2/3} for 3D.Comment: 3 pages, 2 figure

Outward FDI of Malaysia: An Empirical Examination from Macroeconomic Perspective

Outward FDI of Malaysia was nearly non-existent prior to 1970s. Nonetheless, recently Malaysia has not only been able to sustain FDI inflows position, but also emerged as the fifth largest investor among the developing economies in Asia region (UNTACD, 2005). This study aims to investigate the selected macroeconomic determinants of outward FDI of Malaysia, namely income, exchange rate and openness. The Johansen and Juselius cointegration test and the vector error correction model are applied in this study to analyze the quarterly data from 1991:Q1 to 2004:Q4. The findings verified that the outward FDI of Malaysia is determined by income, exchange rate and openness of the economy in both the short- and long-run.

Enhancing Engagement In Virtual Communities

Virtual communities have been growing in the last two decades and have become an important business tool for various purposes. This paper studied the relationships among three constructs—conflict, dissonance, and engagement—in their interaction with one another in virtual communities. Using dissonance as a mediating variable, the relationship between conflict and engagement was analyzed using data collected from 327 virtual community members. The results suggest that conflict has a positive influence on both dissonance and engagement. Dissonance was also positively associated with engagement. To confirm the findings and to fully understand the effect of conflict, more research is needed. For operators of virtual communities and their associated businesses, the most significant implication is that the existence of conflict may heighten the level of engagement. This study is the first step in understanding the relationship between dissonance, perceived conflict, and engagement in the context of virtual communities

Competition between B-Z and B-L transitions in a single DNA molecule: Computational studies

Under negative torsion, DNA adopts left-handed helical forms, such as Z-DNA and L-DNA. Using the random copolymer model developed for a wormlike chain, we represent a single DNA molecule with structural heterogeneity as a helical chain consisting of monomers which can be characterized by different helical senses and pitches. By Monte Carlo simulation, where we take into account bending and twist fluctuations explicitly, we study sequence dependence of B-Z transitions under torsional stress and tension focusing on the interaction with B-L transitions. We consider core sequences, (GC)(n) repeats or (TG)(n) repeats, which can interconvert between the right-handed B form and the left-handed Z form, imbedded in a random sequence, which can convert to left-handed L form with different (tension dependent) helical pitch. We show that Z-DNA formation from the (GC)(n) sequence is always supported by unwinding torsional stress but Z-DNA formation from the (TG)(n) sequence, which are more costly to convert but numerous, can be strongly influenced by the quenched disorder in the surrounding random sequence.National Research Foundation NRF-2012 R1A1A3013044 NRF-2014R1A1A2055681NRF-2012R1A1A2021736IBS-R023-D1NRF-2015R1A2A2A01005916Chemistr

Ultra narrow AuPd and Al wires

In this letter we discuss a novel and versatile template technique aimed to the fabrication of sub-10 nm wide wires. Using this technique, we have successfully measured AuPd wires, 12 nm wide and as long as 20 $\mu$m. Even materials that form a strong superficial oxide, and thus not suited to be used in combination with other techniques, can be successfully employed. In particular we have measured Al wires, with lateral width smaller or comparable to 10 nm, and length exceeding 10 $\mu$m.Comment: 4 pages, 4 figures. Pubblished in APL 86, 172501 (2005). Added erratum and revised Fig.

MOOC Relevance: A Key Determinant of the Success for Massive Open Online Courses

The MOOC (Massive Open Online Course) providers promote their courses as education that builds marketable skills. However, little research examines the role of relevance in the success of MOOCs or how this relevance influences learner behaviors. This study highlights the importance of MOOC relevance by decomposing it into personal relevance and social relevance and then examining their effects on learner satisfaction. Based on Expectation-Confirmation Model and DeLone and McLean’s information system success model, our proposed theoretical framework elaborates on the relationship among personal relevance, social relevance, perceived usefulness, subjective norms, confirmation, satisfaction, and continuance intention. We analyzed survey data collected from 343 MOOC learners, finding both personal and social relevance positively associated with confirmation and satisfaction. Confirmation positively influences perceived usefulness and satisfaction, while continuance intention is enhanced by learner satisfaction and subjective norms. However, the impact of perceived usefulness on satisfaction is not significant. This study contributes to Information Systems (IS) literature by demonstrating the role of relevance in the growth and success of MOOCs. Additionally, our findings contribute to the IS education literature by highlighting the need for more personally and socially relevant curricula if traditional IS programs are to remain competitive in an era of increasing educational opportunities

Ultrafast optical switching of three-dimensional Si inverse opal photonic band gap crystals

We present ultrafast optical switching experiments on 3D photonic band gap crystals. Switching the Si inverse opal is achieved by optically exciting free carriers by a two-photon process. We probe reflectivity in the frequency range of second order Bragg diffraction where the photonic band gap is predicted. We find good experimental switching conditions for free-carrier plasma frequencies between 0.3 and 0.7 times the optical frequency: we thus observe a large frequency shift of up to D omega/omega= 1.5% of all spectral features including the peak that corresponds to the photonic band gap. We deduce a corresponding large refractive index change of Dn'_Si/n'_Si= 2.0% and an induced absorption length that is longer than the sample thickness. We observe a fast decay time of 21 ps, which implies that switching could potentially be repeated at GHz rates. Such a high switching rate is relevant to future switching and modulation applications