COMPARATIVE Studies | Academic Articles

May 2013
M	T	W	T	F	S	S
« Nov
	1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22	23	24	25	26
27	28	29	30	31

Posts Tagged ‘COMPARATIVE studies’

Comparative functional analysis of cyp71av1 natural variants reveals an important residue for the successive oxidation of amorpha-4,11-diene

Abstract: Artemisinin is an antimalarial sesquiterpenoid isolated from the aerial parts of the plant Artemisia annua. CYP71AV1, a cytochrome P450 monooxygenase was identified in the artemisinin biosynthetic pathway. CYP71AV1 catalyzes three successive oxidation steps at the C12 position of amorpha-4,11-diene to produce artemisinic acid. In this study, we isolated putative CYP71AV1 orthologs in different species of Artemisia. Comparative functional analysis of CYP71AV1 and its putative orthologs, together with homology modeling, enabled us to identify an amino acid residue (Ser479) critical for the second oxidation reaction catalyzed by CYP71AV1. Our results clearly show that a comparative study of natural variants is useful to investigate the structure–function relationships of CYP71AV1. [Copyright &y& Elsevier]

November 1, 2012 Tags: AMINO acids, ARTEMISIA annua, BIOSYNTHESIS, COMPARATIVE studies, FUNCTIONAL analysis, OXIDATION
Category: Articles No Comments

The relationship between bank performance and intellectual capital in east asia

In this paper, we develop a performance efficiency value by using data envelopment analysis (DEA) to integrate five perspectives of CAMEL (Capital Adequacy, Asset Quality, Management, Earnings, Liquidity), which is used by the Federal Deposit Insurance Corporation to evaluate banking performance. In addition, we utilize a tiered DEA to categorize banks into four groups. One-way ANOVA is used to analyze differences in CAMEL and intellectual capital (IC) variables across the four groups. CAMEL variables are manifested more strongly in highly efficient groups when compared with inefficient groups. The findings also reveal the importance of IC in achieving high levels of bank efficiency. [ABSTRACT FROM AUTHOR]

October 28, 2012 Tags: BANKING industry, COMPARATIVE studies, DATA envelopment analysis, INTELLECTUAL capital, PERFORMANCE evaluation
Category: Articles No Comments

Fractional mortality rate based on rational interpolating method and its application in actuarial science

This paper attempts to introduce a new method with adjustable parameter for estimating the mortality of fractional age based on rational interpolating theory. The efficiency analysis of the method is given and some conditions the adjustable parameter should satisfy are given in order to meet the need of actuarial practice. We also analyze the relationship between our estimating method and the one based on UDD assumption-the most commonly used in actuarial study and practice. The result shows that the latter is just a special case of our results. Finally we apply our method to the calculations of actuarial present value of life insurance and annuities. Simulations are also done to give a clear comparison between traditional method and our method specified in this paper. [ABSTRACT FROM AUTHOR]

October 25, 2012 Tags: ACTUARIAL science, ANNUITIES, COMPARATIVE studies, LIFE insurance, MORTALITY, PARAMETER estimation, RATIONAL interpolation
Category: Articles No Comments

Mental health of african americans and caribbean blacks in the united states: results from the national epidemiological survey on alcohol and related conditions

Objectives. Previous epidemiological studies have found lower mood, anxiety, and substance use disorder prevalence in Black Americans, in general, compared with White Americans. We estimated the prevalence and persistence of psychiatric disorders in African Americans, Caribbean Blacks, and non-Hispanic Whites. Methods. We drew data from wave 1 (2001-2002) of the National Epidemiological Survey of Alcohol and Related Conditions, a nationally representative sample of US adults, which included 7529 African Americans, 469 Caribbean Blacks, and 24 502 non-Hispanic Whites. Results. Blacks had equal or lower prevalence than Whites of lifetime (adjusted odds ratio [AOR] = 0.6 for African Americans; 0.3 for Caribbean Blacks) and 12-month (AOR = 0.7 for African Americans; 0.4 for Caribbean Blacks) Axis I psychiatric disorders, but higher prevalence of several personality disorders. Among Blacks, Caribbean Blacks had higher prevalence of 12-month psychotic disorders and lower lifetime prevalence of major depressive disorder, alcohol dependence, and drug abuse than African Americans. There were no differences in persistence of disorders between Caribbean Blacks and African Americans. Conclusions. This study yielded new data on prevalence of mental disorders in these groups, which has important implications for clinical work with US Blacks. [ABSTRACT FROM AUTHOR]

October 24, 2012 Tags: BIRTHPLACES, BLACKS -- United States, COMPARATIVE studies, CONFIDENCE intervals, CORRELATION (Statistics), CROSS-sectional method, DATA analysis, DESCRIPTIVE statistics, DISEASE duration, DISEASE prevalence, EPIDEMIOLOGY, LOGISTIC regression analysis, MENTAL depression, PERSONALITY disorders, PSYCHIATRIC epidemiology, PSYCHOSES, RESEARCH -- Finance, SECONDARY analysis, SUBSTANCE abuse, WHITES
Category: Articles No Comments

Sorption of tetracycline on organo-montmorillonites

Abstract: Tetracycline (TC) is a veterinary antibiotic that is frequently detected as pollutant in the environment. Powerful adsorbents are required for removing TC. The present paper compares the TC adsorption capacity of Na-montmorillonite (Na-mont) with six organo-montmorillonites (organo-monts). Three quaternary ammonium cations (QACs) with different alkyl-chain lengths were used as modifiers. Powder X-ray diffraction indicated that the d 001 values of organo-monts increased with increasing the QACs loading and alkyl-chain length. The CECs of the organo-monts were substantially lower than that of Na-mont and decreased with QACs chain length and increased loading. The modeling of the adsorption kinetics revealed that the processes of TC adsorption on the tested samples could be well fitted by the pseudo-second-order equation. The maximum adsorption capacities of TC on the organo-monts (1000–2000mmol/kg) were considerably higher than that on Na-mont (769mmol/kg). Both the Langmuir and Freundlich model could fit the adsorption isotherms. The TC adsorption to the organo-monts increase significantly with decreasing the pH below 5.5 because of the electrostatic interaction, and a high QACs loading performed better than a low loading at around pH 3. [Copyright &y& Elsevier]

July 25, 2012 Tags: ALUMINUM silicates, ANTIBIOTICS, COMPARATIVE studies, POLLUTANTS, QUATERNARY ammonium compounds, SORPTION, TETRACYCLINE, VETERINARY medicine
Category: Articles No Comments

Occurrence, accumulation, attenuation and priority of typical antibiotics in sediments based on long-term field and modeling studies

Abstract: Long-term field and modeling studies were performed to measure and predict occurrence, accumulation, attenuation and priority of typical antibiotics in sediments of the Dagu River in China. The results indicated that the concentrations of antibiotics ranged from lower than the limit of detection to 12.4mg/kg, depending on the accumulation time of these antibiotics in sediments. Compared with the residential and industrial areas, the agricultural region of the watershed was a major source of antibiotic contamination in sediments. Accumulation and attenuation kinetics models were established and successfully applied in the field study. For instance, by 2100, the accumulation model predicted that the concentrations of roxithromycin and oxytetracycline would rise to 13 and 7.3mg/kg, respectively. The first and second order attenuation kinetics models revealed the fate of these antibiotics along the downstream and upstream sediments, respectively. The half-life distances of antibiotic attenuation ranged from 3.5 to 12.4km. Based on the contamination level and trend, a priority factor and an accumulation growth factor were defined to identify the priority pollutants from the antibiotics. Gentamicin and roxithromycin were recognized as the top priority pollutants among the tested antibiotics. In the future, a wider applicability of the methods and models needs to be explored and suggested. [Copyright &y& Elsevier]

July 22, 2012 Tags: ANTIBIOTICS, BIOACCUMULATION, CHEMICAL kinetics, COMPARATIVE studies, INDUSTRIAL sites, MATHEMATICAL models, SEDIMENTS (Geology), WATERSHEDS -- China
Category: Articles No Comments

Bayesian adaptive lasso quantile regression

Recently, variable selection by penalized likelihood has attracted much research interest. In this paper, we propose adaptive Lasso quantile regression (BALQR) from a Bayesian perspective. The method extends the Bayesian Lasso quantile regression by allowing different penalization parameters for different regression coefficients. Inverse gamma prior distributions are placed on the penalty parameters. We treat the hyperparameters of the inverse gamma prior as unknowns and estimate them along with the other parameters. A Gibbs sampler is developed to simulate the parameters from the posterior distributions. Through simulation studies and analysis of a prostate cancer dataset, we compare the performance of the BALQR method proposed with six existing Bayesian and non-Bayesian methods. The simulation studies and the prostate cancer data analysis indicate that the BALQR method performs well in comparison to the other approaches.

July 8, 2012 Tags: BAYESIAN statistical decision theory, CANCER -- Research, COMPARATIVE studies, DATA analysis, GIBBS phenomenon, PERFORMANCE evaluation, REGRESSION analysis, SIMULATION methods
Category: Articles No Comments

Magnetic characteristics analysis of permanent magnet motor by using complex approximation taking account of two-dimensional magnetic properties

This paper presents a complex E&S modeling approach, which is developed with a complex approximation for conventional E&S modeling. Complex E&S modeling is used to analyze a permanent magnet motor and the validity of complex E&S modeling is demonstrated. The computation time of complex E&S modeling can be considerably reduced in comparison with conventional E&S modeling. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(2): 9-16, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21268 [ABSTRACT FROM AUTHOR]

June 23, 2012 Tags: APPROXIMATION theory, COMPARATIVE studies, COMPUTATIONAL complexity, MAGNETIC properties, MATHEMATICAL models, PERMANENT magnet motors
Category: Articles No Comments

Affine-invariant character recognition by progressive removing

Recognizing characters in scene images suffering from perspective distortion is a challenge. Although there are some methods to overcome this difficulty, they are time-consuming. In this paper, we propose a set of affine-invariant features and a new recognition scheme called ‘progressive removing’ that can help reduce the processing time. Progressive removing gradually removes less feasible categories and skew angles by using multiple classifiers. We observed that progressive removing and the use of the affine invariant features reduced the processing time by about 60% in comparison to a trivial algorithm without decreasing the recognition rate. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(2): 55-63, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.22276 [ABSTRACT FROM AUTHOR]

June 16, 2012 Tags: ALGORITHMS, APPROXIMATION theory, COMPARATIVE studies, ELECTRIC distortion, IMAGE analysis, OBSERVATION (Scientific method)
Category: Articles No Comments

academic articles on popular topics

Academic Articles

Archives

Recent Posts