275 research outputs found

    Validation of the Malaysian Chinese-version of the EORTC QLQ-CR29 among Colorectal cancer patients in Malaysia

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    Patient reported outcome research are becoming a very important way of understanding patient’s satisfaction and tolerance with the treatment they receive. This study examined the validity and reliability of the Malaysian Chinese version of the European Organization for Research and Treatment of Cancer (EORTC) colorectal cancer-specific quality of life questionnaire (QLQ-CR29). Patients were recruited at the outpatient clinics of the University of Malaya and Universiti Kebangsaan Medical Centre, Malaysia. The QLQ-CR29 and Karnofsky Performance Scales (KPS) were used. Multi-traits scaling analysis such as Cronbach’s alpha, inter-class correlation (ICC) and known-groups comparisons (Wilcoxon-rank sum test) were performed. Significant level was pre-set at ≤ 0.05. Patients mean age (standard deviation, SD) was 64 (10) years, and 60% were male. Colon cancer was 50%. While 60% had advanced stage (Dukes’ C/D) cancers and about 30% of patients had a stoma. The mean KPS was 80% (SD 10). The internal consistency coefficient (ICC) was 0.89, 0.84, 0.46, and 0.73 for body image, urinary frequency, blood & mucus in stool and stool frequency scales respectively. The correlation coefficients for convergent validity were moderate to large (r ranged from 0.72 to 0.93) across all scales. For the discriminant validity measurements, small to moderate correlations were observed across the scales. The psychometric properties of the Malaysian Chinese version of the QLQ-CR29 were comparable to the original English version. This work provides a translated, culturally adapted, reliable and valid measure of HRQOL for use among Malaysian Chinese patients with colorectal cancer

    Ant Colony Optimization for the Design of Water Distribution Systems

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    During the last decade, evolutionary methods such as genetic algorithms have been developed for the optimal design and operation of water distribution systems. More recently, ant colony optimization algorithms (ACOAs), which are evolutionary methods based on the foraging behavior of ants, been successfully applied to a number of benchmark combinatorial optimization problems. For example, when applied to the traveling salesman problem, ACOAs have been shown to outperform genetic algorithms. In this paper, a formulation is developed which enables ACOAs to be used for the optimal design of water distribution systems. This formulation is applied to a benchmark water distribution system optimization problem and the results are compared with those obtained using genetic algorithms. The findings of this study indicate that the performance of ACOAs is comparable with that of GAs for the case study considered. The GA performed slightly better in terms of finding the optimal solution from different starting positions in the search space, whereas the ACOA perfomed better in terms of the number of evaluations needed to reach the optimum.Holger R. Maier, Angus R. Simpson, W. K. Foong, K. Y. Phang, H. Y. Seah, and C. L. Ta

    Statistical distribution of quantum entanglement for a random bipartite state

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    We compute analytically the statistics of the Renyi and von Neumann entropies (standard measures of entanglement), for a random pure state in a large bipartite quantum system. The full probability distribution is computed by first mapping the problem to a random matrix model and then using a Coulomb gas method. We identify three different regimes in the entropy distribution, which correspond to two phase transitions in the associated Coulomb gas. The two critical points correspond to sudden changes in the shape of the Coulomb charge density: the appearance of an integrable singularity at the origin for the first critical point, and the detachement of the rightmost charge (largest eigenvalue) from the sea of the other charges at the second critical point. Analytical results are verified by Monte Carlo numerical simulations. A short account of some of these results appeared recently in Phys. Rev. Lett. {\bf 104}, 110501 (2010).Comment: 7 figure

    Power plant maintenance scheduling using ant colony optimization: an improved formulation

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    Abstract It is common practice in the hydropower industry to either shorten the maintenance duration or to postpone maintenance tasks in a hydropower system when there is expected unserved energy based on current water storage levels and forecast storage inflows. It is therefore essential that a maintenance scheduling optimizer can incorporate the options of shortening the maintenance duration and/or deferring maintenance tasks in the search for practical maintenance schedules. In this article, an improved ant colony optimization-power plant maintenance scheduling optimization (ACO-PPMSO) formulation that considers such options in the optimization process is introduced. As a result, both the optimum commencement time and the optimum outage duration are determined for each of the maintenance tasks that need to be scheduled. In addition, a local search strategy is presented in this article to boost the robustness of the algorithm. When tested on a five-station hydropower system problem, the improved formulation is shown to be capable of allowing shortening of maintenance duration in the event of expected demand shortfalls. In addition, the new local search strategy is also shown to have significantly improved the optimization ability of the ACO-PPMSO algorithm

    Multiple Neural Oscillators and Muscle Feedback Are Required for the Intestinal Fed State Motor Program

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    After a meal, the gastrointestinal tract exhibits a set of behaviours known as the fed state. A major feature of the fed state is a little understood motor pattern known as segmentation, which is essential for digestion and nutrient absorption. Segmentation manifests as rhythmic local constrictions that do not propagate along the intestine. In guinea-pig jejunum in vitro segmentation constrictions occur in short bursts together with other motor patterns in episodes of activity lasting 40–60 s and separated by quiescent episodes lasting 40–200 s. This activity is induced by luminal nutrients and abolished by blocking activity in the enteric nervous system (ENS). We investigated the enteric circuits that regulate segmentation focusing on a central feature of the ENS: a recurrent excitatory network of intrinsic sensory neurons (ISNs) which are characterized by prolonged after-hyperpolarizing potentials (AHPs) following their action potentials. We first examined the effects of depressing AHPs with blockers of the underlying channels (TRAM-34 and clotrimazole) on motor patterns induced in guinea-pig jejunum, in vitro, by luminal decanoic acid. Contractile episode durations increased markedly, but the frequency and number of constrictions within segmenting bursts and quiescent period durations were unaffected. We used these observations to develop a computational model of activity in ISNs, excitatory and inhibitory motor neurons and the muscle. The model predicted that: i) feedback to ISNs from contractions in the circular muscle is required to produce alternating activity and quiescence with the right durations; ii) transmission from ISNs to excitatory motor neurons is via fast excitatory synaptic potentials (EPSPs) and to inhibitory motor neurons via slow EPSPs. We conclude that two rhythm generators regulate segmentation: one drives contractions within segmentation bursts, the other the occurrence of bursts. The latter depends on AHPs in ISNs and feedback to these neurons from contraction of the circular muscle

    Many body physics from a quantum information perspective

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    The quantum information approach to many body physics has been very successful in giving new insight and novel numerical methods. In these lecture notes we take a vertical view of the subject, starting from general concepts and at each step delving into applications or consequences of a particular topic. We first review some general quantum information concepts like entanglement and entanglement measures, which leads us to entanglement area laws. We then continue with one of the most famous examples of area-law abiding states: matrix product states, and tensor product states in general. Of these, we choose one example (classical superposition states) to introduce recent developments on a novel quantum many body approach: quantum kinetic Ising models. We conclude with a brief outlook of the field.Comment: Lectures from the Les Houches School on "Modern theories of correlated electron systems". Improved version new references adde

    Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

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    Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

    Nonlinear characterization of a bistable energy harvester dynamical system

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    International audienceThis chapter explores the nonlinear dynamics of a piezo-magneto-elastic bistable energy device system regards the influence of external forcing parameters influence on system response. Time series, Poincaré maps, phase space trajectories, and bifurcation diagrams are employed in order to reveals system dynamics complexity and nonlinear effects, such as chaos incidence and hysteresis
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