4,241 research outputs found

    A comparative study on financial performance of hotel industry in Pakistan (Sarena Hotel & Marriott Hotel)

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    The aim of this research is to analyse the financial performance of two big names of Hotel industry of Pakistan (Serena Hotel and Marriott Hotel). Specifically, the study seeks to analyse both hotels using financial ratios. Firstly, a review of the literature on the financial performance of Hotel Industry and use of Ratio analysis is done in order to understand its use for analysis. Financial statements of Hotels are mainly used to conduct this research. Overall, the findings show that both hotels have performed better in 2012 than previous years. It is also seen that both hotels are not maintaining sufficient assets with respect to liabilities (Liquidity ratios). Serena’s profit margin ratio is higher than that of Marriott Hotel. Given the importance of understanding the ratio analysis with need to fill the niche of research on the topic in our country; this study is of great importance to both academia and practitioners in the Hotel Industry of Pakistan. Keywords: Financial Statements, Ratio analysis, Liquidity ratio, Profit margin rati

    Hybrid electric vehicle fuel minimization by DC-DC converter dual-phase-shift control

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    The paper introduces an advanced DC-link variable voltage control methodology that improves significantly the fuel economy of series Hybrid Electric Vehicles (HEVs). The DC-link connects a rectifier, a Dual Active Bridge (DAB) DC-DC converter and an inverter, interfacing respectively the two sources and the load in a series HEV powertrain. The introduced Dual Phase Shift (DPS) proportional voltage conversion ratio control scheme is realized by manipulating the phase shifts of the gating signals in the DAB converter, to regulate the amount of DAB converter power flow in and out of the DC-link. Dynamic converter efficiency models are utilized to account for switching, conduction, copper and core losses. The control methodology is proposed on the basis of improving the individual efficiency of the DAB converter but with its parameters tuned to minimize the powertrain fuel consumption. Since DPS control has one additional degree of freedom as compared to Single Phase Shift (SPS) voltage control schemes, a Lagrange Multiplier optimization method is applied to minimize the leakage inductance peak current, the main cause for switching and conduction losses. The DPS control scheme is tested in simulations with a full HEV model and two associated conventional supervisory control algorithms, together with a tuned SPS proportional voltage conversion ratio control scheme, against a conventional PI control in which the DC-link voltage follows a constant reference. Nonlinear coupling difficulties associated with the integration of varying DC-link voltage in the powertrain are also exposed and addressed

    Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes

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    Purpose: Sub-foveal choroidal thickness (SFCT) is affected in many ocular diseases. The aim of this study was to compare SFCT measurements between Topcon 3D 2000 spectral-domain optical coherence tomography (SD-OCT) and Topcon swept-source OCT (SS-OCT), with different laser wavelengths, in normal and diseased populations.MATERIALS AND Methods: This was a prospective, cross-sectional, noninterventional study including 27 normal volunteers and 27 participants with retinal disease. OCT scans were performed sequentially and under standardized conditions using both SD-OCT and SS-OCT. The OCT scans were evaluated by two independent graders. Paired t-tests and intraclass correlation coefficients (ICCs) were used to assess the statistically significant difference between SFCT measurements as measured by the two devices.Results: Mean SFCT measurements for all 54 participants were 264.9±103.1 mum using SD-OCT (range: 47-470 mum) and 278.5±110.5 mum using SS-OCT (range: 56-502 mum), with an inter-device ICC of 0.850. Greater variability was noted in the diseased eyes. Inter-device ICCs were 0.870 (95% CI; 0.760-0.924) and 0.840 (95% CI; 0.654-0.930) for normal and diseased eyes, respectively. However, the difference was not statistically significant (P=0.132).CONCLUSION: Both machines reliably measure SFCT. Larger studies are needed to confirm these findings

    Synthesis, characterization and antimicrobial potential of transition metal complexes of triacetic lactone

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    Seven novel and biological active transition metal complexes were prepared using 3-nitro- 4-hydroxy -6-methyl-pyran-2-one derivative of triacetic lactone as ligand. These complexes were characterized by elemental analysis, magnetic susceptibility measurement, UV/Vis, FTIR and NMR spectroscopy. These data showed that solid complexes of Ni (II), Co (II), Mn (II), Zn (II) and Fe (II) indicated octahedral geometries while Cu (II) complex was assigned square planar geometry. The antimicrobial activities ofall above mentioned complexes along with ligand were tested against eleven different bacterial strains and ten fungal strains using agar well diffusion assay. Cu (II) complex showed highest inhibition zone against Shigella dysentriae (22.3 mm), greater than standard drug, while the Zn (II) complex showed maximum antifungal activity against Trichophyton simii (18.7 mm). The antimicrobial activities indicated that metal complexes showed enhanced activity as compared to the free ligand

    Synthesis and antibacterial study of some s-substituted aliphatic analogues of 2-mercapto-5-(1-(4-toluenesulfonyl) piperidin-4-yl)-1,3,4-oxadiazole

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    Purpose: To synthesize a series of analogues of 1,3,4-oxadiazole and to evaluate their antibacterial activity.Methods: Ethyl piperidin-4-carboxylate (1) was mixed with 4-toluenesulfonyl chloride (2) in benignant conditions to yield ethyl 1-(4-toluenesulfonyl)piperidin-4-carboxylate (3) and then 1-(4- toluenesulfonyl)piperidin-4-carbohydrazide (4). Intermolecular cyclization of 4 into 2-mercapto-5-(1-(4- toluenesulfonyl) piperidin-4-yl)-1,3,4-oxadiazole (5) was obtained on reflux with CS2 in the presence of KOH. Molecule 5 was stirred with alkyl halides, 6a-i, in DMF in the presence of LiH to synthesize the final compounds, 7a-i. The structures of these molecules were elucidated by Fourier transform infra-red (FTIR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) and electron impact mass spectrometry (EI-MS). Antibacterial activity was evaluated against five bacterial strains, namely, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis, with ciprofloxacin used as standard antibacterial agent.Results: Out of nine synthesized derivatives, compound 7a was the most active against three bacterial strains, S. typhi, E. coli and P. aeruginosa, with minimum inhibitory concentration (MIC) of 9.11 ± 0.40, 9.89 ± 0.45 and 9.14 ± 0.72 μM, respectively, compared with 7.45 ± 0.58, 7.16 ± 0.58 and 7.14 ± 0.18 μM, respectively, for the reference standard (ciprofloxacin). Similarly, compounds 7a - 7c showed relatively good antibacterial activity against B. subtilis strain while compound 7e - 7g revealed good results against S. typhi bacterial strain.Conclusion: The results indicate that S-substituted derivatives of the parent compound are more effective antibacterial agents than the parent compound, even with minor differences in substituents.Keywords: 1,3,4-Oxadiazole, Antibacterial activity, Ethyl piperidin-4-carboxylate, Sulfonamid

    AudioInceptionNeXt: TCL AI LAB Submission to EPIC-SOUND Audio-Based-Interaction-Recognition Challenge 2023

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    This report presents the technical details of our submission to the 2023 Epic-Kitchen EPIC-SOUNDS Audio-Based Interaction Recognition Challenge. The task is to learn the mapping from audio samples to their corresponding action labels. To achieve this goal, we propose a simple yet effective single-stream CNN-based architecture called AudioInceptionNeXt that operates on the time-frequency log-mel-spectrogram of the audio samples. Motivated by the design of the InceptionNeXt, we propose parallel multi-scale depthwise separable convolutional kernels in the AudioInceptionNeXt block, which enable the model to learn the time and frequency information more effectively. The large-scale separable kernels capture the long duration of activities and the global frequency semantic information, while the small-scale separable kernels capture the short duration of activities and local details of frequency information. Our approach achieved 55.43% of top-1 accuracy on the challenge test set, ranked as 1st on the public leaderboard. Codes are available anonymously at https://github.com/StevenLauHKHK/AudioInceptionNeXt.git

    Non-cascaded short-term pumped-storage hydro-thermal scheduling using accelerated particle swarm optimization

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    © 2018 IEEE. This paper presents the implementation of a variant of the famous particle swarm optimization, known as Accelerated Particle Swarm Optimization (APSO), on a non-cascaded or a two-unit hydro-thermal system with consideration of hydal pumping in light loading intervals of hydro-thermal scheduling period. APSO is an easy to program and easy to implement variant of Particle Swarm Optimization (PSO) that has the ability to converge to a good approximate to global optimum within a few iterations. A standard pumped-storage hydrothermal scheduling problem, discussed in existing literature, is considered for the implementation of APSO. A comparison of this implementation is also given with the previously existing implementations of other algorithms

    Antioxidant activities of the selected plants from the family Euphorbiaceae, Lauraceae, Malvaceae and Balsaminaceae

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    Extraction of nine plants selected from the family Euphorbiaceae, Lauraceae, Malvaceae and Balsaminaceae was done in petroleum ether, chloroform, ethyl acetate and methanol/n-butanol in order of increasing polarity using soxhlet apparatus. Total phenolic contents were determined with Folin- Ciocalteu reagent which ranged from 30.5 to 547.0 mg GAE/g of extract. Maximum phenolic contents were found in n-butanol extract of Ricinus communis. Antioxidant activities of these extracts were evaluated through DPPH• radical scavenging, phosphomolybdate and ferric thiocyanate (FTC) methods. Methanolic extract of Cinnamomum zeylanicum and Cinnamomum tamala showed highest antiradical (96.8%) and phosphomolybdate (1.131) activity, respectively, while ethyl acetate extract of R. communis exhibited maximum lipid per-oxidation (FTC) activity (79.3%). IC50 value of chloroform extract of C. tamala (2.2 g/ml) was less than gallic acid (4.4 g/ml), while ethyl acetate and methanol extracts of Abutilon bidentatum, Impatiens bicolor and Impatiens edgeworthii exhibited the IC50 values in the range of 10.0 - 20.0 g/ml

    Synthesis and antibacterial evaluation of 2-(1,3- Benzodioxol-5-ylcarbonyl)arylsulfonohydrazide derivatives

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    Purpose: To study the antibacterial activity of various sulfonamides derived from 1,3-benzodioxol-5- carbohydrazide.Methods: The synthesis involved the conversion of 1,3-benzodioxol-5-carboxylic acid (1) to ethyl 1,3- benzodioxol-5-carboxylate (2) and then to 1,3-benzodioxol-5-carbohydrazide (3). The target molecules, 2-(1,3-benzodioxol-5-ylcarbonyl)arylsulfonohydrazide derivatives (5a-l) were synthesized through a benignant method from aqueous medium by the reaction of 3 and arylsulfonyl chlorides (4a-l). The structural formulae of the synthesized compounds were characterized by infra red spectroscopy (IR), proton nuclear magnetic resonance (1H-NMR) and electron impact mass spectrometry (EI-MS). The compounds were screened for in vitro antibacterial activity by determining their minimum inhibitory concentration (MIC).Results: The molecule, 5k, bearing 2-hydroxy-3,5-dichlorophenyl group exhibited the highest activity with MIC of 11.92 ± 3.40 (S. typhi), 8.37 ± 2.22 (E. coli), 9.28 ± 2.31 (P. aeroginosa), 11.76 ± 1.30 (B. subtilis) and 10.30 ± 1.63 (S. aureus) μmoles/L relative to that of ciprofloxacin with 9.42 ± 1.09, 8.02 ± 2.17, 8.11 ± 1.32, 8.88 ± 2.00 and 9.23 ± 1.87 μmoles/L respectively.Conclusion: The most potent of the synthesized compounds (5k) posesses moderate activity against all the bacterial strains, while 5g remained completely inactive.Keywords: 1,3-Benzodioxol-5-carboxylic acid, Antibacterial activity, Sulfonohydrazide, Synthesi

    Synthesis of N'-Substituted-2-(5-(4-Chlorophenyl)-1,3,4- oxadiazol-2-ylthio)acetohydrazide Derivatives as Suitable Antibacterial Agents

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    Purpose: To evaluate antibacterial activity of a series of molecules bearing 1,3,4-oxadiazole and azomethine moieties.Methods: The 4-chlorobenzoic acid (1) was precursor to N'-substituted-2-(5-(4-chlorophenyl)-1,3,4- oxadiazol-2-ylthio)acetohydrazide, 8a-p, through a multistep synthesis of corresponding ester, 2, hydrazide, 3 and 1,3,4-oxadiazole, 4. The molecule, 4, was subjected to electrophilic substitution by ethyl-2-bromoacetate to yield 5 which was stepped to 2-(5-(4-chlorophenyl)-1,3,4-oxadiazol-2- ylthio)acetohydrazide (6). The target molecules, 8a-p, were synthesized by nucleophilic addition of 6 to arylaldehydes, 7a-p. The proposed structures of all the synthesized molecules were elucidated by Infra Red (IR), Proton Nuclear Magnetic Resonance (1H-NMR) and Electron Impact Mass Spectrometry (EIMS) spectral data. Antibacterial activity was evaluated by the principle that microbial growth is in a log phase of growth and so results in increased absorbance of broth medium which is observed.Results: The molecule, 8b, was active against S. aureus and 8c against S. typhi only. The molecule, 8p, was the most active against S. typhi with minimum inhibitory concentration (MIC) value of 10.04 ± 1.25 μM while 8e was active against E. coli with MIC of 9.45 ± 1.00 μM, both relative to the reference standard, ciprofloxacin, which displayed MIC of 9.13 ± 2.00 and 8.90 ± 1.65 μM, respectively.Conclusion: Most of the synthesized molecules exhibit 50 % antibacterial activity relative to the reference. Molecules 8b and 8c are the least active compounds.Keywords: 1,3,4-Oxadiazole, 4-Chlorobenzoic acid, Antibacterial activity, Azomethin
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