Optimizing hydropower reservoir operation using hybrid genetic algorithm and chaos

Author name used in this publication: Chun-tian CheungAuthor name used in this publication: K. W. Chau2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

The carbon border adjustment mechanism is inefficient in addressing carbon leakage and results in unfair welfare losses

The European Commission has proposed a Carbon Border Adjustment Mechanism (CBAM) to reduce carbon leakage and create a level playing field for its domestic products and imported goods. Nevertheless, the effectiveness of the proposal remains unclear, especially when it triggers threats of retaliation from trading partners of the European Union (EU). We apply a Computable General Equilibrium (CGE) model - Global Trade Analysis Project (GTAP) - to assess the economic and environmental impacts of different CBAM schemes. Here we show that the effectiveness of the CBAM to address carbon leakage risks is rather limited, and the CBAM raises concerns over global welfare costs, GDP losses, and violation of equality principles. Trade retaliation leads to multiplied welfare losses, which would mostly be borne by poor countries. Our results question the carbon leakage reduction effect of a unilateral trade policy and suggest that climate change mitigation still needs to be performed within the framework of international cooperation

Floating Microparticulate Oral Diltiazem Hydrochloride Delivery System for Improved Delivery to Heart

Purpose: To formulate and evaluate floating microparticulate oral diltiazem delivery system for possible delivery to the heart.Method: Floating microspheres were prepared using cellulose acetate and Eudragit RS100 polymers by emulsion solvent evaporation technique. The dried floating microspheres were evaluated for micromeritic properties (flow properties, density, particle size determination) scanning as well as by electron microscopy, and in vitro floatability and drug release studies.Results: The microspheres showed good buoyancy, good flow properties (angle of repose ranging from 24.29 to 29.02 º), particle size (262.09 to 409.60 μm) and good drug loading (74.29 to 92.09 %). The microspheres were porous, hollow and spherical. All the formulations showed good in vitro controlled drug release in the range of 77.62 ± 2.12 to 97.50 ± 1.04 % at the end of 12 h. Drug release was diffusion-controlled and followed zero order kinetics.Conclusion: Microparticulate floating (gastroretentive) oral drug delivery system of diltiazem prepared using cellulose acetate and Eudragit R5100 may be an effective alternative to conventional oral tablets for cardiac drug delivery.Keywords: Cardiac, Microparticulate, Drug release, Gastroretentive, Floating microspheres, Diltiazem hydrochlorid

The synchrotron self-compton model for x-ray and γ-ray emission from pulsars

We compare the observed X-ray luminosity emitted from pulsars with that calculated from various theoretical models and find that the X-ray emission from six pulsars is much stronger than that predicted by theoretical models. We suggest that these pulsars with unusually intense X-ray emission could also be γ-ray emitters. Electrons/positrons are accelerated in the outer magnetospheric gap and lose most of their energy via curvature radiation (primary photons), which will be converted to secondary e ± pairs outside the gap in collision with the secondary X-rays. A simple synchrotron self-Compton model is then used to calculate the X-ray and γ-ray emission from the secondary e ± pairs. This model only contains a single free parameter, which characterizes the size of the acceleration region and can be estimated by comparison with that of the Crab pulsar. Our model results are consistent with the observed data and upper limits of γ-ray emission and phase separation between pulses. Other implications for future observations are also discussed in the text.published_or_final_versio

Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity

Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))

Qualitative characterization of healthcare wastes

The biological hazard inherent in the clinical wastes should be considered during the management and treatment process as well as the disposal into the environment. In this chapter, the risks associated with the clinical wastes as well as the management of these wastes are discussed. The chapter focused on reviewing the types of healthcare wastes generated from hospitals and clinics as well as the regulations and management practices used for these wastes. Moreover, the health risk associated with the infectious agents which have the potential to be transmitted into the environment. It has appeared that the clinical wastes represent real hazards for the human health and the environment if they were not managed properly

Pulsed and unpulsed gamma-ray emission from millisecond pulsars

We use the outer gap model to study the gamma-ray emission and pair production processes of millisecond pulsars. The small light cylinder of millisecond pulsars results in a large optical depth for gamma rays produced inside the light cylinder. Electron/position cascade will take place until the energy of emitted gamma rays is less than a specific threshold energy (E crit). The model for the pulsed gamma-ray spectrum is F1(Eγ) ∼ Eγ -2 for Eγ ≤ E crit. Furthermore, electrons/positrons accelerated in the outer gap can continue to interact with the low-energy gamma rays beyond the light cylinder to produce very high energy gamma rays. The subsequent pair production and radiation processes can produce unpulsed high-energy photons in the energy range of the EGRET detector on board the Compton Gamma Ray Observatory with a model spectrum F 2(Eγ) ∼ Eγ∼ -3/2 for most millisecond pulsars. We have calculated the theoretical spectra of PSR J0751 + 18, PSR 1821-24, and PSR 1937+21 to illustrate our model. Unpulsed gamma-ray emission from other sources, e.g., 47 Tuc, are discussed also. © 1996. The American Astronomical Society. All rights reserved.published_or_final_versio

A case-control study and meta-analysis of the association of eNOS rs1799983 SNP with stroke risk

The endothelial nitric oxide synthase (eNOS) rs1799983 polymorphism is known to increase the risk towards stroke, but data is under-reported in Malaysian population. Therefore, this study sought to investigate this association in a Malaysian population and in a comprehensive meta-analysis. Genotyping of the eNOS rs1799983 polymorphism was performed for 241 Malaysians using a hydrolysis probe. Odd ratio with 95% confidence interval was calculated. Meta-analysis was conducted using the Comprehensive Meta-Analysis software ver. 2.2.064. A p-value less than 0.05 was considered statistically significant. Overall, our results showed that the presence of eNOS rs1799983-T allele increases the risk towards stroke, particularly in males, fast-food goers and Malaysian Chinese. The meta-analysis showed that the rs1799983 polymorphism is significantly associated with an increase ischemic stroke risk in the recessive and allelic models. After stratified with population, these associations remain significant in the Asian population but not in the Caucasian population. In summary, this study establishes a significant relationship between the eNOS rs1799983 polymorphism with gender, lifestyle and ethnicity differences towards stroke risk in the Malaysian population. In addition, our meta-analysis suggests that the eNOS rs1799983 polymorphism is associated with an increase risk of ischemic stroke

Inclusive wealth index measuring sustainable development potentials for Chinese cities

The UN Sustainable Development Goals (SDGs) are the blueprint to achieve a better and more sustainable future. To achieve the goal, tracking progress — not just on a national level, but locally — is crucial to guide future policy development. While sustainability assessment at the national evel is quite advanced in China, similar assessments focusing at the regional or even at the city-level are currently lacking. Here, we advanced the Inclusive Wealth Index (IWI) framework, which is firstly proposed by the United Nations Development Programme, through taking water wealth into account and adjusting the variable based on data availability. Then we investigate the sustainability performance of 210 cities in China in 2016 via the advanced version of the IWI framework. The analysis makes a holistic assessment based on produced, human, and natural capital, as well as considering heterogeneities in economy, social, and environmental conditions across these cities. We find that cities clustered in the eastern parts of China are characterized by high levels of sustainability performance and increasing capacities for sustainability, largely driven by their high quality and quantity of human capital. In comparison, the western cities have a large amount of low-skilled human capital and low levels of produced capital, which determines their low sustainability performance. Cities clustered in the north are heavily dependent on low value-added products and resource-intensive industries. Furthermore, we make projections of the IWI and its three components for different cities from 2020 to 2030, referring to the index systems presented in city planning which describe the development speed of income, education, fixed asset investment, forests etc. In the future, cities in central and western clusters show considerable potential for increasing IWI per capita, whereas cities with a dominant energy sector in the north would face declining capacity for sustainability due to the exhaustion of fossil fuels and raw materials. By fully taking account of and adapting to local circumstances, we tailor-design pathways for different types of cities to grow their sustainability potentials. Those resources-dependent cities in the north could avoid the impending decline by gradually developing their human and produced capital while abandoning their resource dependency. Our study contributes to city-level sustainable development in China through the lens of per capita IWI and the potential future dynamics of changing compositions in their capital

Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption

Explosive energy release is a common phenomenon occurring in magnetized plasma systems ranging from laboratories, Earth's magnetosphere, the solar corona and astrophysical environments. Its physical explanation is usually attributed to magnetic reconnection in a thin current sheet. Here we report the important role of magnetic flux rope structure, a volumetric current channel, in producing explosive events. The flux rope is observed as a hot channel prior to and during a solar eruption from the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamic Observatory (SDO). It initially appears as a twisted and writhed sigmoidal structure with a temperature as high as 10 MK and then transforms toward a semi-circular shape during a slow rise phase, which is followed by fast acceleration and onset of a flare. The observations suggest that the instability of the magnetic flux rope trigger the eruption, thus making a major addition to the traditional magnetic-reconnection paradigm.Comment: 13 pages, 3 figure