A travel safety model for women commuters

One of the most serious discussions on the contemporary urban travel in Malaysia is that of the design facilities that have failed to meet the demand of women travelers. This has led to a higher level of concern for a much safer travelling environment for many women travelers within the Kuala Lumpur conurbation. The main aim of this research is to determine the factors of travel safety among women commuter. This empirical research has used the structural fear dimension model as the underpinning theory. A quantitative and personal administered approach through quota sampling was used to conduct the study in Kuala Lumpur urban area. A sample of 312 respondents were selected throughout the survey. The results indicates that only bus service, infrastructure had significantly affect the travel safety of women travelers but when comes to moderating variable effects, only the combination of bus service and infrastructure affect the travel safety of a women travelers

Emerging role of microRNAs in diagnosis and treatment of various diseases including ovarian cancer

MicroRNAs (miRNAs) represent a class of small non-coding RNAs that control gene expression by targeting messenger RNA (mRNA). Recently, it has been demonstrated that miRNA expression is altered in many human diseases including cancers, suggesting that miRNA may play a potential role in the pathogenesis of different diseases. It has also been reported that there is a unique expression pattern of miRNAs in the disease state differing from the normal state. In this review, we focus on the miRNA signatures in different human diseases including cancers. Such signatures may be used as diagnostic and prognostic markers

Ultrafast demagnetization in the sp-d model: a theoretical study

We propose and analyze a theoretical model of ultrafast light-induced magnetization dynamics in systems of localized spins that are coupled to carriers' spins by sp-d exchange interaction. A prominent example of a class of materials falling into this category are ferromagnetic (III,Mn)V semiconductors, in which ultrafast demagnetization has been recently observed. In the proposed model light excitation heats up the population of carriers, taking it out of equilibrium with the localized spins. This triggers the process of energy and angular momentum exchange between the two spin systems, which lasts for the duration of the energy relaxation of the carriers. We derive the Master equation for the density matrix of a localized spin interacting with the hot carriers and couple it with a phenomenological treatment of the carrier dynamics. We develop a general theory within the sp-d model and we apply it to the ferromagnetic semiconductors, taking into account the valence band structure of these materials. We show that the fast spin relaxation of the carriers can sustain the flow of polarization between the localized and itinerant spins leading to significant demagnetization of the localized spin system, observed in (III,Mn)V materials.Comment: 15 pages, 8 figure

Spin relaxation in low-dimensional systems

We review some of the newest findings on the spin dynamics of carriers and excitons in GaAs/GaAlAs quantum wells. In intrinsic wells, where the optical properties are dominated by excitonic effects, we show that exciton-exciton interaction produces a breaking of the spin degeneracy in two-dimensional semiconductors. In doped wells, the two spin components of an optically created two-dimensional electron gas are well described by Fermi-Dirac distributions with a common temperature but different chemical potentials. The rate of the spin depolarization of the electron gas is found to be independent of the mean electron kinetic energy but accelerated by thermal spreading of the carriers.Comment: 1 PDF file, 13 eps figures, Proceedings of the 1998 International Workshop on Nanophysics and Electronics (NPE-98)- Lecce (Italy

Collective oscillations driven by correlation in the nonlinear optical regime

We present an analytical and numerical study of the coherent exciton polarization including exciton-exciton correlation. The time evolution after excitation with ultrashort optical pulses can be divided into a slowly varying polarization component and novel ultrafast collective modes. The frequency and damping of the collective modes are determined by the high-frequency properties of the retarded two-exciton correlation function, which includes Coulomb effects beyond the mean-field approximation. The overall time evolution depends on the low-frequency spectral behavior. The collective mode, well separated from the slower coherent density evolution, manifests itself in the coherent emission of a resonantly excited excitonic system, as demonstrated numerically.Comment: 4 pages, 4 figures, accepted for publication in Physical Review Letter

Nonlinear Optical studies of the Transient Coherence in the Quantum Hall System

We review recent investigations of the femtosecond non-linear optical response of the two-dimensional electron gas (2DEG) in a strong magnetic field. We probe the Quantum Hall (QH) regime for filling factors $\nu \sim 1$. Our focus is on the transient coherence induced via optical excitation and on its time evolution during early femtosecond timescales. We simultaneously study the interband and intraband coherence in this system by using a nonlinear spectroscopic technique, transient three-pulse four wave mixing optical spectroscopy, and a many-body theory. We observe striking differences in the temporal and spectral profile of the nonlinear optical signal between a modulation doped quantum well system (with the 2DEG) and a similar undoped quantum well (without a 2DEG). We attribute these qualitative differences to Coulomb correlations between the photoexcited electron-hole pairs and the 2DEG. We show, in particular, that intraband many-particle coherences assisted by the inter-Landau-level magnetoplasmon excitations of the 2DEG dominate the femtosecond nonlinear optical responce. The most striking effect of these exciton-magnetoplasmon coherences is a large off-resonant four-wave-mixing signal in the case of very low photoexcited carrier densities, not observed in the undoped system, with strong temporal oscillations and unusually symmetric temporal profile.Comment: 22 pages, 9 figures; review article to be published in Solid State Communication

Spin sensitive bleaching and monopolar spin orientation in quantum wells

Spin sensitive bleaching of the absorption of far-infrared radiation has been observed in $p$-type GaAs/AlGaAs quantum well structures. The absorption of circularly polarized radiation saturates at lower intensities than that of linearly polarized light due to monopolar spin orientation in the first heavy hole subband. Spin relaxation times of holes in $p$-type material in the range of tens of ps were derived from the intensity dependence of the absorption.Comment: Figures have been updated due to technical printing problems (Postscript mismatch

Government expenditure, manufacturing growth and CO2 emission: A causality analysis in Malaysia

The main objective of the study is to explore government expenditure, CO2 emission and manufacturing output in one model. These comprehensive literature reviews related to this topic of interest prove evidence upon variations towards the causality relationship that exists between government expenditure, CO2 emission and manufacturing output. Most of past literatures had studied on the relationship of these variables, however separately. This study is done in order to test the relationship between government expenditure. CO2 emission and manufacturing output on pollution in Malaysia. The data is secondarily obtained from The World Bank, The Eurostat, The European Environment Agency (EEA) and the international Monetary Fund (IMF) on the basis of a 39 of data collection from 2005 to 2019. The amounts of government expenditure, CO2 emission and manufactu1ing output are then valued from the data usable. The study aims to analyses to whether or not do the variables hold causal to each other. This study discusses on the impacts of economic sectors on pollution the government expenditure, CO2 emission and manufacturing consumption as its variables. Upon examining the study, an annual time series data covering the period of 2005-2019 in Malaysia were used. Models such as augmented Dickey-Fuller (ADF) unit root test, Johansen and Juselius (1990) co-integration test, vector error correction model test and Granger causality test were employed, each its own purposes. The conclusion on the findings limitation of the studies and suggestion for future references will later on be discussed in this chapter

Government expenditure, manufacturing growth, C02 emission: A causality analysis in Malaysia

The main objective of the study is to explore government expenditure, C02 emission and manufacturing output in one model. These comprehensive literature reviews related to this topic of interest prove evidence upon variations towards the causality relationship that exists between government expenditure, C02 emission and manufacturing output. Most of past literatures had studied on the relationship of these variables, however separately. This study is done in order to test the relationship between government expenditure. C02 emission and manufacturing output on pollution in Malaysia. The data is secondarily obtained from The World Bank, The Eurostat, The European Environment Agency (EEA) and the international Monetary Fund (IMF) on the basis of a 39 of data collection from 2005 to 2019. The amounts of government expenditure, C02 emission and manufactu1ing output are then valued from the data usable. The study aims to analyses to whether or not do the variables hold causal to each other. This study discusses on the impacts of economic sectors on pollution the government expenditure, C02 emission and manufacturing consumption as its variables. Upon examining the study, an annual time series data covering the period of 2005 to 2019 in Malaysia were used. Models such as Augmented Dickey-Fuller (ADF) unit root test, Johansen and Juselius (1990) Co- Integration test, Vector Error Correction Model test and Granger Causality test were employed, each its own purposes. The conclusion on the findings limitation of the studies and suggestion for future references will later on be discussed in this chapter