One-parameter scaling theory for DNA extension in a nanochannel

Experiments measuring DNA extension in nanochannels are at odds with even the most basic predictions of current scaling arguments for the conformations of confined semiflexible polymers such as DNA. We show that a theory based on a weakly self-avoiding, one-dimensional "telegraph" process collapses experimental data and simulation results onto a single master curve throughout the experimentally relevant region of parameter space and explains the mechanisms at play.Comment: Revised version. 5 pages, 4 figures, revised version, supplementary informatio

Generating compact classifier systems using a simple artificial immune system

Current artificial immune system (AIS) classifiers have two major problems: 1) their populations of B-cells can grow to huge proportions, and 2) optimizing one B-cell (part of the classifier) at a time does not necessarily guarantee that the B-cell pool (the whole classifier) will be optimized. In this paper, the design of a new AIS algorithm and classifier system called simple AIS is described. It is different from traditional AIS classifiers in that it takes only one B-cell, instead of a B-cell pool, to represent the classifier. This approach ensures global optimization of the whole system, and in addition, no population control mechanism is needed. The classifier was tested on seven benchmark data sets using different classification techniques and was found to be very competitive when compared to other classifiers

FOREIGN DIRECT INVESTMENT AND SERVICES TRADE: EVIDENCE FROM MALAYSIA AND SINGAPORE

Services trade is an important source of growth in Malaysia and Singapore. Both economies are export-oriented and actively court foreign direct investment (FDI) to advance their economic objectives of industrialisation and economic development. This paper examines the causal linkages between inward FDI and the country’s engagement in services trade in bi-variate and tri-variate VAR frameworks. The empirical findings for Singapore show evidence of bidirectional causality between inward FDI and the total trade volume in services (i.e. the absolute sum of payments and receipts) as well as between FDI and services imports (in the tri-variate specification). This may reflect her relative open foreign investment policy and free trade regime in services. For Malaysia, the evidence of causality is weaker and unidirectional, from inward FDI to services imports. These findings are consistent with the different stages of economic development and openness attained by the two sample countries, and they provide useful background for trade and foreign investment policies and development strategies.Causality; services trade; foreign direct investment

Exact ground states and correlation functions of chain and ladder models of interacting hardcore bosons or spinless fermions

By removing one empty site between two occupied sites, we map the ground states of chains of hardcore bosons and spinless fermions with infinite nearest-neighbor repulsion to ground states of chains of hardcore bosons and spinless fermions without nearest-neighbor repulsion respectively, and ultimately in terms of the one-dimensional Fermi sea. We then introduce the intervening-particle expansion, where we write correlation functions in such ground states as a systematic sum over conditional expectations, each of which can be ultimately mapped to a one-dimensional Fermi-sea expectation. Various ground-state correlation functions are calculated for the bosonic and fermionic chains with infinite nearest-neighbor repulsion, as well as for a ladder model of spinless fermions with infinite nearest-neighbor repulsion and correlated hopping in three limiting cases. We find that the decay of these correlation functions are governed by surprising power-law exponents.Comment: 20 pages, 18 figures, RevTeX4 clas

Removal of Linear Alkyl Benzenesulphonate by Quaternized Rice Husk

The potential for the use of quaternized rice husk as a sorbent for the removal of linear alkyl benzenesulphonate from aqueous solution was investigated. Both batch and column studies were carried out. The results of the batch studies indicate that sorption was pH dependent, with maximum sorption being attained at pH 2.2. The removal of linear alkyl increased as the temperature increased from 4 to 50°C; thereafter uptake remained constant with further increase in temperature. The presence of anions such as CI', Hl04 ', HPO/ and SO/, had little effect on sorption. Experimental data could be fitted into the Langmuir isotherm with a maximum sorption capacity of 243.9 mg/g at pH 2.2 and 28 ± 2C. In the column studies, results show that a linear relationship existed between service time and bed-depth. However, flow rate of influent had no effect on breakthrough time once it was above 10 ml/min

Fe-doping-induced evolution of charge-orbital ordering in a bicritical-state manganite

Impurity effects on the stability of a ferromagnetic metallic state in a bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of metal-insulator transition have been investigated by substituting a variety of transition-metal atoms for Mn ones. Among them, Fe doping exhibits the exceptional ability to dramatically decrease the ferromagnetic transition temperature. Systematic studies on the magnetotransport properties and x-ray diffraction for the Fe-doped crystals have revealed that charge-orbital ordering evolves down to low temperatures, which strongly suppresses the ferromagnetic metallic state. The observed glassy magnetic and transport properties as well as diffuse phase transition can be attributed to the phase-separated state where short-range charge-orbital-ordered clusters are embedded in the ferromagnetic metallic matrix. Such a behavior in the Fe-doped manganites form a marked contrast to the Cr-doping effects on charge-orbital-ordered manganites known as impurity-induced collapse of charge-orbital ordering.Comment: 8 pages, 7 figure