5,278 research outputs found

    Generalization of the coupled dipole method to periodic structures

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    We present a generalization of the coupled dipole method to the scattering of light by arbitrary periodic structures. This new formulation of the coupled dipole method relies on the same direct-space discretization scheme that is widely used to study the scattering of light by finite objects. Therefore, all the knowledge acquired previously for finite systems can be transposed to the study of periodic structures.Comment: 5 pages, 2 figures, and 1 tabl

    The effect of 12 weeks regular physical activity and vitamin E in the treatment of non-alcoholic steatohepatitis: A pilot study

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    Background: Despite the prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH), there was no treatment has been proven to be effective in these common diseases. Although many studies have shown that lifestyle modifications such as increasing physical activities and exercise could be effective in the treatment of these common diseases, the optimal strategy was still not determined. According to the beneficial effects of antioxidant agents in the treatment of NASH, vitamin E has been used for this purpose by some clinicians. We designed this study for assessing beneficial effects of regular physical activity on the biochemical and imaging responses in patients with NASH and comparing this with vitamin E as an accepted treatment for NASH. Materials and Methods: This study was Randomized and single-blind clinical trials were carried out in Gonbad-e Kavus through which a total of 30 consecutive patients with the ultra sonographic diagnosis of non-alcoholic steatohepatitis (NASH)were enrolled and randomized to one of the three groups: Vitamin E 800 mg/day, regular physical activity, or both. Results: In all treatment groups improvement in liver transaminases level, serum lipids and ultrasonographic grading of fatty liver occurred after three months of treatment. When these decrement was compared between the treatment groups, there was no statistically significant difference in the value of improvement between the three groups (ANOVA: p>0.5). I.e. all three interventions improved the biochemical and ultrasonographic finding of fatty liver in the same way. Both groups with regular exercise had significant mean weight loss in comparison with the vitamin E group (a mean decrease of 3.0 kg in exercise group, 5.8 kg in subjects on regular exercise plus vitamin E and 0.2 kg in vitamin E group, ANOVA: p=0.04). Conclusion: There were no significant differences between exercise and vitamin E alone or in combination regarding the reduction in the level of liver enzymes and sonographic evidences of fatty liver although both resulted in significant improvements in biochemical endpoints. This implies that physical activity could be considered as effective as vitamin E in the improvement of biochemical and ultrasonographic presentations of NASH and the addition of Vitamin E does not offer any benefits. According to the findings of this pilot study a full-powered study with a control group should be designed. © 2015, Iranian Association of Gastroenterology and Hepatology. All rights reserved

    The effect of 12 weeks regular physical activity and vitamin E in the treatment of non-alcoholic steatohepatitis: A pilot study

    Get PDF
    Background: Despite the prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH), there was no treatment has been proven to be effective in these common diseases. Although many studies have shown that lifestyle modifications such as increasing physical activities and exercise could be effective in the treatment of these common diseases, the optimal strategy was still not determined. According to the beneficial effects of antioxidant agents in the treatment of NASH, vitamin E has been used for this purpose by some clinicians. We designed this study for assessing beneficial effects of regular physical activity on the biochemical and imaging responses in patients with NASH and comparing this with vitamin E as an accepted treatment for NASH. Materials and Methods: This study was Randomized and single-blind clinical trials were carried out in Gonbad-e Kavus through which a total of 30 consecutive patients with the ultra sonographic diagnosis of non-alcoholic steatohepatitis (NASH)were enrolled and randomized to one of the three groups: Vitamin E 800 mg/day, regular physical activity, or both. Results: In all treatment groups improvement in liver transaminases level, serum lipids and ultrasonographic grading of fatty liver occurred after three months of treatment. When these decrement was compared between the treatment groups, there was no statistically significant difference in the value of improvement between the three groups (ANOVA: p>0.5). I.e. all three interventions improved the biochemical and ultrasonographic finding of fatty liver in the same way. Both groups with regular exercise had significant mean weight loss in comparison with the vitamin E group (a mean decrease of 3.0 kg in exercise group, 5.8 kg in subjects on regular exercise plus vitamin E and 0.2 kg in vitamin E group, ANOVA: p=0.04). Conclusion: There were no significant differences between exercise and vitamin E alone or in combination regarding the reduction in the level of liver enzymes and sonographic evidences of fatty liver although both resulted in significant improvements in biochemical endpoints. This implies that physical activity could be considered as effective as vitamin E in the improvement of biochemical and ultrasonographic presentations of NASH and the addition of Vitamin E does not offer any benefits. According to the findings of this pilot study a full-powered study with a control group should be designed. © 2015, Iranian Association of Gastroenterology and Hepatology. All rights reserved

    Genetic relationships among Rosa species based on random amplified polymorphic DNA (RAPD) markers

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    To investigate the genetic diversity of Rosa accessions, random amplified polymorphism DNA (RAPD) approach was employed. Nine of ten primers amplified 138 scorable RAPD loci with 111 polymorphic bands (80%). Percentages of polymorphic bands ranged from 75 to 100%. Sizes of amplified DNA fragments ranged from 250 to 6000 bp and were used for statistical analyses. Cluster analysis based on presence-absence of bands used Jaccard similarity coefficient and the unweighted pair group method with arithmetic averages (UPGMA). Genetic similarities between Rosa cultivars ranged from 0.42 to 0.84. The dendrogram revealed two main clusters, revealing considerable genetic diversity among these cultivars. Cluster I was divided into two subgroups. RAPD proves a useful tool for evaluating genetic diversity and relationships among different rose cultivars.Key words: Genetic diversity, (random amplified polymorphism DNA) RAPD markers, polymorphism, Rosaceae

    Assessing drivers’ preferences for hybrid electric vehicles (HEV) in Spain

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    With the aim of analyzing preferences for hybrid electric vehicles (HEVs), two stated preference methods (a contingent valuation exercise and a discrete choice experiment (DCE)) were used in a survey conducted in a representative sample of Spanish drivers. Overall, our findings show robustness between the willingness to pay (WTP) estimates elicited via a latent class model (LCM) and those from a payment card question. In both cases results show an average positive WTP, although insufficient to actually cover the extra cost of HEVs. The lack of interest for HEVs may be motivated by different reasons, including the low level of information related to this technology, and additional false believes about the autonomy of these vehicles. Furthermore, drivers who declare a willingness to buy HEVs do not always do so for environmental reasons, but rather for reputational issues related to their self-image. Thus, in order to increase the market share for HEV vehicles in the Spanish market, informative campaigns and additional economic incentives may be designed.info:eu-repo/semantics/acceptedVersio

    Raman spectroscopy of iodine-doped double-walled carbon nanotubes

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    We present a Raman spectroscopy study of iodine-intercalated (p-type-doped) double-walled carbon nanotubes. Double-walled carbon nanotubes (DWCNTs) are synthesized by catalytic chemical vapor deposition and characterized by Raman spectroscopy. The assignment of the radial breathing modes and the tangential modes of pristine DWCNTs is done in the framework of the bond polarization theory, using the spectral moment method. The changes in the Raman spectrum upon iodine doping are analyzed. Poly-iodine anions are identi- fied, and the Raman spectra reveal that the charge transfer between iodine and DWCNTs only involves the outer tubes

    Tingkat Pelayanan Selasar Pejalan Kaki Di Pasar Kahayan Palangkaraya

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    Pedestrians have a weak position when mixed with vehicular traffic . Therefore, it required facilities for pedestrians , which can be a pedestrian corridor. In reality, it is often found that the pedestrian corridors are improperly used, when the carridor is used for trading places resulting reduced spaces for pedestrians. All of these in turn reduces the level of service for pedestrians. This study was conducted in the market area of Jalan Kahayan, Cilik Riwut, in the City of Palangkaraya. Observations were made at the peak and at the normal time. The level of service is measured based on the concept of Level of Service described in the US Highway Capacity Manual 1994. The results of this study are expected to be used as a reference material for designing pedestrian facilities which are not at present available in the Indonesian Highway Capacity Manual . The results indicate that the level of service in the pedestrian corridor of Pasar Kahayan is D in peak condition, C in normal conditions, and D in a combined time conditions

    Tracking Multidecadal Lake Water Dynamics with Landsat Imagery and Topography/Bathymetry

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    An edited version of this paper was published by AGU. Copyright 2019 American Geophysical Union.Water resource management is of critical importance due to its close relationship with nearly every industry, field, and lifeform on this planet. The success of future water management will rely upon having detailed data of current and historic water dynamics. This research leverages Google Earth Engine and uses Landsat 5 imagery in conjunction with bathymetry and Shuttle Radar Topography Mission digital elevation model data to analyze long‐term lake dynamics (water surface elevation, surface area, volume, volume change, and frequency) for Lake McConaughy in Nebraska, USA. Water surface elevation was estimated by extracting elevation values from underlying bathymetry and digital elevations models using 5,994 different combinations of water indices, water boundaries, and statistics for 100 time periods spanning 1985–2009. Surface elevation calculations were as accurate as 0.768 m root mean square error (CI95% [0.657, 0.885]). Water volume change calculations found a maximum change of 1.568 km3 and a minimum total volume of only 23.97% of the maximum reservoir volume. Seasonal and long‐term trends were identified, which have major affects regarding regional agriculture, local recreation, and lake water quality. This research fills an existing gap in optical remote sensing‐based monitoring of lakes and reservoirs, is more robust and outperforms other commonly used monitoring techniques, increases the number of water bodies available for long‐term studies, introduces a scalable framework deployable within Google Earth Engine, and enables data collection of both gauged and ungauged water bodies, which will substantially increase our knowledge and understanding of these critical ecosystems

    Dynamics of single polymers under extreme confinement

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    We study the dynamics of a single chain polymer confined to a two dimensional cell. We introduce a kinetically constrained lattice gas model that preserves the connectivity of the chain, and we use this kinetically constrained model to study the dynamics of the polymer at varying densities through Monte Carlo simulations. Even at densities close to the fully-packed configuration, we find that the monomers comprising the chain manage to diffuse around the box with a root mean square displacement of the order of the box dimensions over time scales for which the overall geometry of the polymer is, nevertheless, largely preserved. To capture this shape persistence, we define the local tangent field and study the two-time tangent-tangent correlation function, which exhibits a glass-like behavior. In both closed and open chains, we observe reptational motion and reshaping through local fingering events which entail global monomer displacement.Comment: 22 pages, 18 figures, slightly extended version to appear in JSTA

    Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

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    Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation
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