50 research outputs found

    A Gene Expression Screen Identifies \u3cem\u3eEARLI1\u3c/em\u3e as a Novel Vernalization-Responsive Gene in \u3cem\u3eArabidopsis Thaliana\u3c/em\u3e

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    Vernalization promotes early ïŹ‚owering in late ecotypes of Arabidopsis thaliana. The mechanisms of vernalization are poorly understood. A subtractive hybridization approach was used to isolate vernalization-responsive genes from a late-ïŹ‚owering ecotype of Arabidopsis thaliana based on the premise that transcript levels of such genes would increase with cold treatment and remain high even after removal of the vernalization stimulus. EARLI1 is the ïŹrst Arabidopsis gene shown to be stably activated by vernalization. The abundance of its RNA is progressively elevated by vernalization and remains high for at least 20 days at room temperature. The basal level of EARLI1 RNA is higher in early-ïŹ‚owering ecotypes, but is increased also after vernalization. Vernalization and subsequent growth in long-day photoperiods have an additive or synergistic effect on EARLI1 activation. EARLI1 RNA levels are also transiently induced by brief exposures to cold, but not to abscisic acid. EARLI1 is thus a novel vernalization-responsive gene in Arabidopsis thaliana that can be used to investigate vernalization-speciïŹc transcriptional regulation

    A Two-Stage Method of Localization of Sources of Harmonics in Current in a Power System

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    The paper deals with localization of sources of harmonics in a power system. At the beginning, the reasons for undertaking investigations are outlined. Then, the theoretical background of the presented method is presented. The method uses examination of the so-called voltage rate to localize the dominant harmonic source. During this examination it is assumed that (i) the voltage and current at the point of common coupling are measured, (ii) at the first stage internal impedances of equivalent sources representing the customer and utility sides are known, (iii) at the second stage only approximate knowledge of the mentioned impedances is possessed. After the principle of the method is described, features of the method are analyzed. At the end, the attention is paid to the main advantages of the method

    Impact of today's media on university student's body image in Pakistan: a conservative, developing country's perspective

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    <p>Abstract</p> <p>Background</p> <p>Living in a world greatly controlled by mass media makes it impossible to escape its pervading influence. As media in Pakistan has been free in the true sense of the word for only a few years, its impact on individuals is yet to be assessed. Our study aims to be the first to look at the effect media has on the body image of university students in a conservative, developing country like Pakistan. Also, we introduced the novel concept of body image dissatisfaction as being both negative and positive.</p> <p>Methods</p> <p>A cross-sectional study was conducted among 7 private universities over a period of two weeks in the city of Karachi, Pakistan's largest and most populous city. Convenience sampling was used to select both male and female undergraduate students aged between 18 and 25 and a sample size of 783 was calculated.</p> <p>Results</p> <p>Of the 784 final respondents, 376 (48%) were males and 408 (52%) females. The mean age of males was 20.77 (+/- 1.85) years and females was 20.38 (+/- 1.63) years. Out of these, 358 (45.6%) respondents had a positive BID (body image dissatisfaction) score while 426 (54.4%) had a negative BID score. Of the respondents who had positive BID scores, 93 (24.7%) were male and 265 (65.0%) were female. Of the respondents with a negative BID score, 283 (75.3%) were male and 143 (35.0%) were female. The results for BID vs. media exposure were similar in both high and low peer pressure groups. Low media exposure meant positive BID scores and vice versa in both groups (p < 0.0001) showing a statistically significant association between high media exposure and negative body image dissatisfaction. Finally, we looked at the association between gender and image dissatisfaction. Again a statistically significant association was found between positive body image dissatisfaction and female gender and negative body image dissatisfaction and male gender (p < 0.0001).</p> <p>Conclusions</p> <p>Our study confirmed the tendency of the media to have an overall negative effect on individuals' body image. A striking feature of our study, however, was the finding that negative body image dissatisfaction was found to be more prevalent in males as compared to females. Likewise, positive BID scores were more prevalent amongst females.</p

    Gender and ethnic disparities contributing to overweight in California adolescents

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    To explore differences in health behaviors and factors contributing to overweight among 12 to 17 year olds in California. Data from the 2005 California Health Interview Survey for 3,315 adolescents self-identified as Latino, Asian, or white were reviewed. Adolescents reported their weight, height, gender, ethnicity, parents’ educational level, household income, physical activity, sedentary activity, breakfast consumption, and family meals. Overall 34% of boys and 22% of girls in this study were overweight (&gt;85th percentile for age and gender). Approximately 38% of Latinos, 25% of whites, and 16% of Asians were overweight. Latinos were more than twice as likely to be overweight as whites (2.07) and Asians (2.53). Younger adolescents (12–13 years old) and adolescents whose family income is less than 200% of the federal poverty level were more likely to be overweight. Low level of parental education is a risk factor for Latino and Asian girls and white and Latino boys. White girls with a lower socioeconomic status and white boys with more than 2 h daily of television, video, and computer time were more likely to be overweight. Results suggest gender and ethnic variations in factors that contribute to overweight in California adolescents. To influence the current overweight epidemic, clinicians must develop culturally sensitive and gender-specific interventions that address the unique needs of an ethnically diverse adolescent population

    Isolation and characterization of EARLI1, a vernalization-responsive gene in Arabidopsis thaliana

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    In order to gain a clearer understanding of the molecular processes that are induced by vernalization, a subtractive hybridization technique was employed to isolate vernalization-responsive genes from very-late flowering Col- FRI -SF2 Arabidopsis thaliana seedlings. An up-regulated cDNA fragment was isolated that corresponds to the EARLI1 gene which has previously been shown to be responsive to aluminum induction. We have found that EARLI1 is expressed in all vegetative tissues of 7-day-old vernalized seedlings grown under short days and that long day photoperiod has an additive effect on vernalization-induced EARLI1 expression. EARLI1 is also up regulated in early-flowering Nossen and Columbia ecotypes in response to vernalization. However, in the very early-flowering Landsberg ecotype, EARLI1 is expressed equally in unvernalized and vernalized plants. There are no significant ecotype-specific polymorphisms within a 1300-by region upstream from the EARLI1 start codon in Columbia, Nossen and Landsberg plants, which show greater than 95% nucleotide identity. EARLI1 is transiently induced by cold shock but not by exogenous abscisic acid, a stress phytohormone. In contrast to other cold shock genes EARLI1 expression is maintained at least 20 days after vernalization treatment and RNA levels progressively increase with increasing periods of vernalization. Sequence analysis of EARLI1 upstream DNA predicts putative abscisic acid, G-box, light regulated and an ethylene response element. In addition, a canonical low-temperature response element lays 2000bp upstream of and oriented away from EARLI1 . Transgenic plants containing an EARLI1 -genomic -500 bp::GUS reporter gene fusion did not exhibit detectable GUS activity. However, a -1500 by fusion exhibited spatial expression in the root elongation zone, root/hypocotyl transition zone, cotyledons, premature leaves, trichomes, dihescence zone, sepals, stamens and carpel tips in unvernalized Col-FRI -Sf2 plants. One of these transgenic plants also exhibited differential GUS expression in response to cold shock and touch but not to vernalization. A central proline-rich and predicted C-terminal transmembrane domain suggests EARLI1 may function in cell wall modification

    Application of the Tabu Search algorithm for localization of capacitor banks in a power system

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    ArtykuƂ traktuje o znajdowaniu najkorzystniejszej lokalizacji baterii kondensatorĂłw w sieci elektroenergetycznej. Po ogĂłlnym omĂłwieniu rozwiązywania tego zadania autorzy skupili uwagę na wykorzystaniu algorytmu poszukiwania z tabu (Tabu Search). W dalszej częƛci pracy znajdujemy zasady postępowania wedƂug algorytmu poszukiwania z tabu. Po tym zaprezentowano charakterystykę rĂłĆŒnych metod znajdowania optymalnej lokalizacji baterii kondensatorĂłw, ktĂłrych wspĂłlną cechą jest stosowanie algorytmu poszukiwania z tabu. Na zakoƄczenie artykuƂu dokonano porĂłwnania przedstawionych metod lokalizacji baterii kondensatorĂłw.The paper discusses the process of finding the most optimal locations for capacitor banks within a power network. After general presenting the solution of this task, the authors focused on the application of the tabu search algorithm. A further part of the paper presents rules for applying the tabu search algorithm to the considered task, and various methods for finding the optimal capacitor bank locations using that algorithm are presented. Finally, the previously presented methods for finding the optimal capacitor bank locations are compared
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