UNDERSTANDING WORLD COMMODITY PRICES Returns, Volatility and Diversification

In recent times, the prices of internationally-traded commodities have reached record highs and there is considerable uncertainty regarding their future. This phenomenon is partially driven by strong demand from a small number of emerging economies, such as China and India. This paper places the recent commodity price boom in historical context, drawing on an investigation of the long-term time-series properties, and presents unique features for 33 individual commodity prices. Using a new methodology for examining cross-sectional variation of commodity returns and its components, we find strong evidence that the prices of world primary commodities are extremely volatile. In addition, prices are roughly 30 percent more volatile under floating than under fixed exchange rate regimes. Finally, using the capital asset pricing model as a loose framework, we find that global macroeconomic risk components have become relatively more important in explaining commodity price volatility.

Site-directed mutagenesis to enhance thermostability of Aspergillus awamori glucoamylase expressed in Saccharomyces cerevisiae

A program of site-directed mutagenesis was undertaken to enhance thermostability of Aspergillus awamori glucoamylase. Nine mutations were designed, based on three different irreversible thermoinactivation mechanisms of glucoamylase. Each mutant was expressed in Saccharomyces cerevisiae, and their production, activities, and irreversible thermoinactivation rates were determined;First, the Asn182 and Asn395 residues were each replaced with Gln to reduce their deamidation rates. Asn395, but not Asn182, was N-glycosylated by yeast. Deletion of the N-glycan linked to Asn395 did not affect specific activity, but greatly decreased enzyme secretion and thermostability. Replacement of Asn182 by Gln did not change glucoamylase specific activity or thermostability, while replacement by Asp, which was previously performed by Dr. Ufuk Bakir, decreased specific activity about 25% but increased thermostability moderately at pH 4.5 below 70°C. Both mutations of Asn182 increased glucoamylase production;Second, by analyzing N-terminal sequences and amino acid compositions of hydrolyzed enzyme fragments after heating, the Asp126-Gly127, Asp257-Pro258, and Asp293-Gly294 bonds in Aspergillus niger glucoamylase were found to undergo hydrolysis at elevated temperatures and mildly acidic pHs, causing irreversible thermoinactivation. Mutations Asp126 → Glu and Gly127 → Ala in recombinant A. awamori glucoamylase decreased specific activities and increased irreversible thermoinactivation rates at pH 4.5. Replacement of Asp257 with Glu and Asp293 with Glu or Gln moderately decreased specific activities, but greatly reduced cleavage of the Asp257-Pro258 and Asp293-Gly294 bonds. Mutation Asp257 → Glu significantly decreased protein production and moderately increased thermostability at pH 4.5 up to 70°C, but not at pHs 3.5 and 5.5. Replacement of Asp293 with either Glu or Gln significantly raised protein production and slightly increased thermostability at pH 3.5 and 4.5, but not at pH 5.5;Finally, three Gly residues that impart flexibility to the helices to which they belong were substituted with Ala. Mutation Gly57 → Ala did not affect irreversible glucoamylase thermostability, but greatly improved glucoamylase production. In contrast, simultaneous substitution of Gly137 and Gly139 with Ala decreased irreversible thermoinactivation rates at pH 4.5 by half, but greatly impeded protein production. Neither mutation affected enzyme specific activity

Adaptive Ttwo-phase spatial association rules mining method

Since huge amounts of spatial data can be easily collected from various applications, ranging from remote sensing technology to geographical information system, the extraction and comprehension of spatial knowledge is a more and more important task. Many excellent studies on Remote Sensed Image (RSI) have been conducted for potential relationships of crop yield. However, most of them suffer from the performance problem because their techniques for mining association rules are based on Apriori algorithm. In this paper, two efficient algorithms, two-phase spatial association rules mining and adaptive two-phase spatial association rules mining, are proposed for address the above problem. Both methods primarily conduct two phase algorithms by creating Histogram Generators for fast generating coarse-grained spatial association rules, and further mining the fine-grained spatial association rules w.r.t the coarse-grained frequently patterns obtained in the first phase. Adaptive two-phase spatial association rules mining method conducts the idea of partition on an image for efficiently quantizing out non-frequent patterns and thus facilitate the following two phase process. Such two-phase approaches save much computations and will be shown by lots of experimental results in the paper.Facultad de Informátic

The Relationship between Knowledge and Medication Compliance Behavior among Patients with Tuberculosis

Tuberculosis (TB) remains the highest priority among infectious diseases in the world today with increasing morbidity and mortality every year. Adherence to treatment plays an important role in the success of therapy among TB patients. This study aims to explore the relationship between demographic characteristics, knowledge, and medication compliance behavior among patients with tuberculosis in Indonesia. This study was descriptive correlational and cross-sectional design with the total sample was 150 tuberculosis confirmed in Medan Pulmonary Hospital, Indonesia. In this study found that there is a significant relationship between ethnicity and medication adherence (continues variable) with p = 0.01. Meanwhile when medication compliance behavior was treated as categorical variables, a significant relationship was found between medication compliance behavior and medical history (p = 0.03), smoking (p = 0.005), and alcohol (p = 0.03) among tuberculosis patients in Indonesia. In the multivariate analysis, multiple linear regression was performed which surprisingly shows that education was significantly associated with knowledge of TB (p = 0,02), and ethnicity (0.04)

Development and validation of the short-form Adolescent Health Promotion Scale.

BACKGROUND: Health-promoting lifestyle choices of adolescents are closely related to current and subsequent health status. However, parsimonious yet reliable and valid screening tools are scarce. The original 40-item adolescent health promotion (AHP) scale was developed by our research team and has been applied to measure adolescent health-promoting behaviors worldwide. The aim of our study was to examine the psychometric properties of a newly developed short-form version of the AHP (AHP-SF) including tests of its reliability and validity. METHODS: The study was conducted in nine middle and high schools in southern Taiwan. Participants were 814 adolescents randomly divided into two subgroups with equal size and homogeneity of baseline characteristics. The first subsample (calibration sample) was used to modify and shorten the factorial model while the second subsample (validation sample) was utilized to validate the result obtained from the first one. The psychometric testing of the AHP-SF included internal reliability of McDonald's omega and Cronbach's alpha, convergent validity, discriminant validity, and construct validity with confirmatory factor analysis (CFA). RESULTS: The results of the CFA supported a six-factor model and 21 items were retained in the AHP-SF with acceptable model fit. For the discriminant validity test, results indicated that adolescents with lower AHP-SF scores were more likely to be overweight or obese, skip breakfast, and spend more time watching TV and playing computer games. The AHP-SF also showed excellent internal consistency with a McDonald's omega of 0.904 (Cronbach's alpha 0.905) in the calibration group. CONCLUSION: The current findings suggest that the AHP-SF is a valid and reliable instrument for the evaluation of adolescent health-promoting behaviors. Primary health care providers and clinicians can use the AHP-SF to assess these behaviors and evaluate the outcome of health promotion programs in the adolescent population

Adaptive Ttwo-phase spatial association rules mining method

Since huge amounts of spatial data can be easily collected from various applications, ranging from remote sensing technology to geographical information system, the extraction and comprehension of spatial knowledge is a more and more important task. Many excellent studies on Remote Sensed Image (RSI) have been conducted for potential relationships of crop yield. However, most of them suffer from the performance problem because their techniques for mining association rules are based on Apriori algorithm. In this paper, two efficient algorithms, two-phase spatial association rules mining and adaptive two-phase spatial association rules mining, are proposed for address the above problem. Both methods primarily conduct two phase algorithms by creating Histogram Generators for fast generating coarse-grained spatial association rules, and further mining the fine-grained spatial association rules w.r.t the coarse-grained frequently patterns obtained in the first phase. Adaptive two-phase spatial association rules mining method conducts the idea of partition on an image for efficiently quantizing out non-frequent patterns and thus facilitate the following two phase process. Such two-phase approaches save much computations and will be shown by lots of experimental results in the paper.Facultad de Informátic