23,413 research outputs found
Character-Level Language Modeling with Deeper Self-Attention
LSTMs and other RNN variants have shown strong performance on character-level
language modeling. These models are typically trained using truncated
backpropagation through time, and it is common to assume that their success
stems from their ability to remember long-term contexts. In this paper, we show
that a deep (64-layer) transformer model with fixed context outperforms RNN
variants by a large margin, achieving state of the art on two popular
benchmarks: 1.13 bits per character on text8 and 1.06 on enwik8. To get good
results at this depth, we show that it is important to add auxiliary losses,
both at intermediate network layers and intermediate sequence positions.Comment: 8 pages, 7 figure
Numerical approximations for population growth model by Rational Chebyshev and Hermite Functions collocation approach: A comparison
This paper aims to compare rational Chebyshev (RC) and Hermite functions (HF)
collocation approach to solve the Volterra's model for population growth of a
species within a closed system. This model is a nonlinear integro-differential
equation where the integral term represents the effect of toxin. This approach
is based on orthogonal functions which will be defined. The collocation method
reduces the solution of this problem to the solution of a system of algebraic
equations. We also compare these methods with some other numerical results and
show that the present approach is applicable for solving nonlinear
integro-differential equations.Comment: 18 pages, 5 figures; Published online in the journal of "Mathematical
Methods in the Applied Sciences
Investigating the Spectrum of Biological Activity of Substituted Quinoline-2-Carboxamides and Their Isosteres
In this study, a series of thirty-five substituted quinoline-2-carboxamides and thirty-three substituted naphthalene-2-carboxamides were prepared and characterized. They were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial species. N-Cycloheptylquinoline-2-carboxamide, N-cyclohexylquinoline-2-carboxamide and N-(2-phenylethyl)quinoline-2-carboxamide showed higher activity against M. tuberculosis than the standards isoniazid or pyrazinamide and 2-(pyrrolidin-1-ylcarbonyl)quinoline and 1-(2-naphthoyl)pyrrolidine expressed higher activity against M. kansasii and M. avium paratuberculosis than the standards isoniazid or pyrazinamide. The most effective antimycobacterial compounds demonstrated insignificant toxicity against the human monocytic leukemia THP-1 cell line. The PET-inhibiting activity expressed by IC50 value of the most active compound N-benzyl-2-naphthamide was 7.5 μmol/L. For all compounds, the structure-activity relationships are discussed
Study of Aging and Production of Wine from Grape Fruit by Fermentation Process
Fermentation biotechnology is an important industrial process for the production of alcoholic beverages including wine. However, aging of wine is always an important issue during production. In present study a attempt has made to produce wine by fermentation process along with the assesment of aging of wine. In this experiment Grape fruit (jufeng) was used as a raw material and fermentation process was carried out with yeast (Saccharomyces cerevisiae) at 28 degrees C. During experiment growth of yeast cell, total solid contents and degree of liquor alcohol was considered critically. The various alcoholic compounds were analyzed with selective method of gas chromatography. Results obtained in the present study indicates that volume of all compounds like ethyl acetate, propyl alcohol, isobutyl alcohol, isoamyl acetate,isoamyl alcohol and ethyl formate was increased with the function of time during fermentation. While during aging process the contents of methyl acetate, ethyl acetate, isoamyl acetate and ethyl lactate were increased but isoamyl alcohol decreased. The levels of propyl alcohol and isobutyl alcohol fell after short period of time. However, no significant effects of aging process on methyl acetate, ethyl acetate, isobutyl alcohol, isoamyl alcohol and ethyl lactate (p\u3e0.05) were observed. Whereas significant effects of aging on the propyl alcohol and isoamyl acetate (p\u3c0.05) were observed
N-Substituted 5-Amino-6-methylpyrazine-2,3-dicarbonitriles: Microwave-Assisted Synthesis and Biological Properties
In this work a series of 15 N-benzylamine substituted 5-amino-6-methyl-pyrazine-2,3-dicarbonitriles was prepared by the aminodehalogenation reactions using microwave assisted synthesis with experimentally set and proven conditions. This approach for the aminodehalogenation reaction was chosen due to its higher yields and shorter reaction times. The products of this reaction were characterized by IR, NMR and other analytical data. The compounds were evaluated for their antibacterial, antifungal and herbicidal activity. Compounds 3 (R = 3,4-Cl), 9 (R = 2-Cl) and 11 (R = 4-CF3) showed good antimycobacterial activity against Mycobacterium tuberculosis (MIC = 6.25 µg/mL). It was found that the lipophilicity is important for antimycobacterial activity and the best substitution on the benzyl moiety of the compounds is a halogen or trifluoromethyl group according to Craig’s plot. The activities against bacteria or fungi were insignificant. The presented compounds also inhibited photosynthetic electron transport in spinach chloroplasts and the IC50 values of the active compounds varied in the range from 16.4 to 487.0 µmol/L. The most active substances were 2 (R = 3-CF3), 3 (R = 3,4-Cl) and 11 (R = 4-CF3). A linear dependence between lipophilicity and herbicidal activity was observed
Catalytic Wet Oxidation of Phenol by Hydrogen Peroxide over Pillared Clay Catalyst
Extrudates of Al-Fe Pillared Clay Catalyst Suitable for Packed-Bed Operations Are Evaluated for Wastewater Treatment Via a Wet Oxidation Process Employing Hydrogen Peroxide as the Oxidant. the Reaction Was Carried Out in a Semibatch Basket Reactor under Rather Mild Conditions. Operational Parameters Were Studied under the Following Conditions: Temperature from 25 to 90 °C, Atmospheric Pressure, Initial Phenol Concentration from 100 to 2000 Ppm of the Liquid Phase, Catalyst Loading from 0 to 10 G/L, and Input H2O2 Concentration from 0.15 to 0.6 Mol/L. under These Conditions, the Al-Fe Pillared Clay Catalyst Achieves a Total Elimination of Phenol and Significant Total Organic Carbon (TOC) Removal. This Catalyst Can Be Used Several Times Without Any Change in its Catalytic Properties, and Hence, It Would Be a Promising Catalyst for Industrial Wastewater Treatment. the Reaction Takes Place to a Significant Extent Both in the Liquid Phase and on the Catalyst Surface. Hence, Apparent Kinetic Models Were Developed by Formulating the Reaction Rate in Two Kinetic Expressions that Separately Consider the Homogeneous and Heterogeneous Contributions. using the Second-Order Approach for the Homogeneous Reaction and the Langmuir-Hinshelwood Approach for the Heterogeneous Reaction, the Developed Kinetic Models Describe Well the Removal of Phenol and the Formed Intermediate Carbon over the Entire Range of the Variables Studied
Liquid Holdup and Pressure Drop in the Gas-Liquid Cocurrent Downflow Packed-Bed Reactor under Elevated Pressures
An Experimental Investigation of the Residence Time Distribution, Liquid Holdup, and Pressure Drop in a Gas-Liquid Downflow Packed Bed Reactor with Porous Particles Operated under Elevated Pressures is Presented. the Effects of the Two-Phase Flow Rates and Reactor Pressures on the External Liquid Holdup and Pressure Drop Are Discussed. a Mechanistic Model, Which Accounts for the Interaction between the Gas and Liquid Phases by Incorporating the Shear and Velocity Slip Factors between Phases, is Employed to Predict the External Liquid Holdup and Pressure Drop for the Experimentally Covered Flow Regime. the Involved Parameters, Such as Shear and Velocity Slip Factors and Ergun Single-Phase Flow Bed Constants, Are Calculated from the Correlations Developed Via Neural Network Regression. the Model\u27s Predictions and the Experimental Observations at Elevated Pressure Are Compared. © 2004 Elsevier Ltd. All Rights Reserved
Catalytic Wet Air Oxidation of Phenol in Concurrent Downflow and Upflow Packed-Bed Reactors over Pillared Clay Catalyst
An Experimental Study is Presented for Comparing the Behavior of a Packed Bed Reactor in the Catalytic Liquid-Phase Oxidation of Aqueous Phenol with Two Modes of Operation, Downflow and Upflow. the Operating Parameters Investigated Included Temperature, Reactor Pressure, Gas Flowrate, Liquid Hourly Space Velocity and Feed Concentration. Because of the Completely Wetted Catalyst, the Upflow Reactor Generally Performs Better for High Pressures and Low Feed Concentrations When the Liquid Reactant Limitation Controls the Rate. the Interaction between the Reactor Hydrodynamics, Mass Transfer, and Reaction Kinetics is Discussed. for Both Operation Modes, Complete Phenol Removal and Significant Total Organic Carbon (TOC) Reduction Can Be Achieved at Rather Mild Conditions of Temperature (150-170°C) and Total Pressure (1.5-3.2 MPa). the Results Show that the Phenol and TOC Conversion Are Considerably Affected by the Temperature, While the Air Pressure Only Has Minor Influence. Total Elimination of TOC is Difficult Since Acetic Acid, as the Main Intermediate, is Resistant to Catalytic Wet Oxidation. All Tests Were Conducted over Extrudates of Fe-Al Pillared Clay Catalyst, Which is Stable and Maintains its Activity during the Long-Term Experimental Process. No Significant Catalyst Deactivation Due to Metal Ion Leaching and Polymer Deposition Was Detected. © 2004 Elsevier Ltd. All Rights Reserved
Job Allocations as Cultural Sorting in a Culturally Diverse Organizational Context
This study addresses the inadequacy of the career and diversity literatures in explaining the dynamics of job allocations in a culturally diverse organizational context. In order to better understand this topic, we conducted a qualitative study involving personal interviews with 50 Emiratis and international employees who worked in managerial positions in the United Arab Emirates (UAE). The purpose of the study was to explore the unique challenges associated with managing a culturally diverse workforce and explore the role of culture in allocating jobs among employees with diverse cultural backgrounds. Despite the perceived value of having a culturally diverse workforce, our findings indicate a lack of effective diversity management strategies for dealing with challenges and issues associated with a high level of cultural diversity in the participating organizations. This study provides insights into the impact of cultural/nationality-based stereotypes on job allocations as well as on organizational outcomes. Based on the findings, we discussed implications for research and practice and as well as for policy makers
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