777 research outputs found

    Time Series and Related Topics. In Memory of Ching-Zong Wei

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    A major research area of Ching-Zong Wei (1949--2004) was time series models and their applications in econometrics and engineering, to which he made many important contributions. A conference on time series and related topics in memory of him was held on December 12--14, 2005, at Academia Sinica in Taipei, where he was Director of the Institute of Statistical Science from 1993 to 1999. Of the forty-two speakers at the conference, twenty contributed to this volume. These papers are listed under the following three headings.Comment: Published at http://dx.doi.org/10.1214/074921706000001120 in the IMS Lecture Notes Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

    Global versus local brand: perceived quality and status-seeking motivation in the automobile industry

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    The purpose of this research is to examine the influence of status-seeking motivation on perceived quality of a global versus local automobile brand in Malaysia. The data for this research was collected through 303 questionnaires from young working adults within the Klang Valley. Data was analysed using repeated measure t-test and results show that a global brand is generally preferred in terms of perceived quality in regards to wealth, achievement and enhance social standings. Likewise, regardless of high or low status-seeking motivation, a global brand is still preferred over a local brand

    Involvement of µ-Opioid Receptor in Methamphetamine-Induced Behavioral Sensitization

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    Methamphetamine is a potent addictive stimulant drug that activates certain systems in the brain. It is a member of the amphetamine family, but the effects of methamphetamine are much more potent, longer lasting, and more harmful to the central nervous system. Repeated administration of methamphetamine induces behavioral sensitization, which is considered to be related to compulsive drug-seeking behavior. Although the mechanism responsible for methamphetamine-induced behavioral sensitization remains unclear, it is believed that the mesolimbic dopaminergic system in the central nervous system plays a critical role in the development of behavioral sensitization. Our previous studies indicate that the involvement of the μ-opioid receptor system underlies the development of methamphetamine-induced behavioral sensitization. Understanding the mechanisms of behavioral sensitization that are regulated by the μ-opioid receptor system would be helpful in developing therapeutic programs against methamphetamine addiction. This review briefly discusses the neural circuitry and cellular mechanisms that are known to play a central role in methamphetamine-induced behavioral sensitization and outlines the role of the μ-opioid receptor system in the development of methamphetamine-induced sensitization

    Cost-Benefit Analysis for the MIL-STD-1916: A Case Study

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    The purpose of this study is to numerically investigate the MIL-STD-1916 sampling plans, via the relationships between sampling verification levels and gross profits. The producer’s viewpoint, expected sampling inspection costs, costs due to customer rejection and the final gross profits are evaluated in a pseudo data case study. A hyper-geometric distribution compound with Poisson distribution is used to compute the qualifying probability and the customer rejection probability. The empirical results reveal that the industry must pay more attention to the impact of sampling inspection costs; if commercial quality control is not rigorous, gross profits could be seriously eroded.Key words: Gross profit; Hyper-geometric distribution; MIL-STD-1916 sampling plans; Poisson distribution; Qualifying probabilit

    TESTING OF CONNECTIONS TAKEN FROM OLD NAILED ROOF TRUSSES

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    Experimental testing of nailed connections taken from old roof trusses is presented in this paper. To enable the further use and preservation of nailed roof trusses, it is important to understand how the nail corrosion and aging processes of steel and wood affect the load-bearing capacity and deformation behaviour of such structures. The hypothesis was investigated whether corroded nails allow an increase in load-bearing capacity. Several old and new joints were tested in a first test series, and the results were very promising regarding the initial assumption. However, more tests must be carried out to verify the results

    1,3-Bis(2-chloro­phen­yl)thio­urea: a monoclinic polymorph

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    The title compound, C13H10Cl2N2S, represents a monoclinic polymorph of the previously reported ortho­rhom­bic form [Ramnathan et al. (1996 ▶). Acta Cryst. C52, 134–136]. The mol­ecule is twisted with the dihedral angle between the benzene rings being 55.37 (7)°. The N—H atoms are syn to each other, which contrasts their anti disposition in the ortho­rhom­bic form. In the crystal, mol­ecules assemble into zigzag chains along the c axis via N—H⋯S hydrogen bonds. Chains are connected into layers via C—H⋯Cl inter­actions, and these stack along the a axis

    Enhancement of tolerance development to morphine in rats prenatally exposed to morphine, methadone, and buprenorphine

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    [[abstract]]BACKGROUND: Abuse of addictive substances is a serious problem that has a significant impact on areas such as health, the economy, and public safety. Heroin use among young women of reproductive age has drawn much attention around the world. However, there is a lack of information on effects of prenatal exposure to opioids on their offspring. In this study, an animal model was established to study effects of prenatal exposure to opioids on offspring. METHODS: Female pregnant Sprague-Dawley rats were sub-grouped to receive (1) vehicle, (2) 2-4 mg/kg morphine (1 mg/kg increment per week), (3) 7 mg/kg methadone, and (4) 3 mg/kg buprenorphine, subcutaneously, once or twice a day from E3 to E20. The experiments were conducted on animals 8-12 weeks old and with body weight between 250 and 350 g. RESULTS: Results showed that prenatal exposure to buprenorphine caused higher mortality than other tested substance groups. Although we observed a significantly lower increase in body weight in all of the opioid-administered dams, the birth weight of the offspring was not altered in all treated groups. Moreover, no obvious behavioral abnormality or body-weight difference was noted during the growing period (8-12 weeks) in all offspring. When the male offspring received morphine injection twice a day for 4 days, the prenatally opioid-exposed rats more quickly developed a tolerance to morphine (as shown by the tail-flick tests), most notably the prenatally buprenorphine-exposed offspring. However, the tolerance development to methadone or buprenorphine was not different in offspring exposed prenatally to methadone or buprenorphine, respectively, when compared with that of the vehicle controlled group. Similar results were also obtained in the female animals. CONCLUSIONS: Animals prenatally exposed to morphine, methadone, or buprenorphine developed tolerance to morphine faster than their controlled mates. In our animal model, prenatal exposure to buprenorphine also resulted in higher mortality and much less sensitivity to morphine-induced antinociception than prenatal exposure to morphine or methadone. This indicates that buprenorphine in higher doses may not be an ideal maintenance drug for treating pregnant women. This study provides a reference in selecting doses for clinical usage in treating pregnant heroin addicts

    Functional phosphoproteomic profiling of phosphorylation sites in membrane fractions of salt-stressed Arabidopsis thaliana

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    <p>Abstract</p> <p>Background</p> <p>Under conditions of salt stress, plants respond by initiating phosphorylation cascades. Many key phosphorylation events occur at the membrane. However, to date only limited sites have been identified that are phosphorylated in response to salt stress in plants.</p> <p>Results</p> <p>Membrane fractions from three-day and 200 mM salt-treated Arabidopsis suspension plants were isolated, followed by protease shaving and enrichment using Zirconium ion-charged magnetic beads, and tandem mass spectrometry analyses. From this isolation, 18 phosphorylation sites from 15 <it>Arabidopsis </it>proteins were identified. A unique phosphorylation site in 14-3-3-interacting protein AHA1 was predominately identified in 200 mM salt-treated plants. We also identified some phosphorylation sites in aquaporins. A doubly phosphorylated peptide of PIP2;1 as well as a phosphopeptide containing a single phosphorylation site (Ser-283) and a phosphopeptide containing another site (Ser-286) of aquaporin PIP2;4 were identified respectively. These two sites appeared to be novel of which were not reported before. In addition, quantitative analyses of protein phosphorylation with either label-free or stable-isotope labeling were also employed in this study. The results indicated that level of phosphopeptides on five membrane proteins such as AHA1, STP1, Patellin-2, probable inactive receptor kinase (At3g02880), and probable purine permease 18 showed at least two-fold increase in comparison to control in response to 200 mM salt-stress.</p> <p>Conclusion</p> <p>In this study, we successfully identified novel salt stress-responsive protein phosphorylation sites from membrane isolates of abiotic-stressed plants by membrane shaving followed by Zr<sup>4+</sup>-IMAC enrichment. The identified phosphorylation sites can be important in the salt stress response in plants.</p

    Durability properties of mortar containing steel slag as supplementary cementitious material

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    The use of steel slag (SS) as supplementary cementitious material (SCM) is promising from the perspective of environmental protection and resource utilization. Previous studies have shown that using 20% SS replacement tends to decrease the strength of concrete. However, few studies have investigated the effect of SS on the durability properties of concrete, such as resistance to ammonium nitrate attack and resistance to sulfate attack. In this study, SS powder has been used as SCM with replacement ratio of 0, 10%, 20%, 30% and 40% to manufacture mortar. Compressive strength test, ammonium nitrate attack test and sulfate attack test have been conducted to investigate the properties of hardened mortar specimens. From this study, it is concluded that the increase in SS replacement ratio caused the decrease in mortar strength, the exposure to sulfate solution could increase the strength of mortar, and the exposure to ammonium nitrate solution led to the decrease in strength of mortar

    The effect of particle sizes of steel slag as cement replacement in high strength concrete under elevated temperatures

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    This study investigates the impact of utilizing steel slag (SS) as a partial substitute for cement in high strength concrete (HSC) under high temperatures covering a range from 200 °C to 800 °C over a duration of 2 h. Two particle sizes of SS: 75 µm and 150 µm, were utilized as fine steel slag (FSS) and coarse steel slag (CSS). This study evaluates several physicochemical and compressive strengths of the HSC. After conducting the compressive strength, both residual compressive strength (RCS) and relative residual compressive strength (RRCS) were calculated. Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and X-Ray Diffraction (XRD) analysis were carried out to analyze the physicochemical properties of HSC before and after subjected to elevated temperatures. The findings indicate an increase in the RCS of all specimens up to 400 °C. The replacement of FSS for cement enhances the compressive strength of HSC at ambient temperature, and FSS performs better than CSS up to 200 °C. However, beyond 400 °C, CSS exhibits a superior RRCS compared to FSS. XRD analysis confirms mineralogical changes in the HSC after exposure to fire, including the decomposition of C-S-H gel and the conversion of calcium hydroxide into calcium carbonate. The present study suggests that incorporating CSS in HSC has the potential to enhance its performance under high temperature conditions
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