4,212 research outputs found
Schwarzschild-de Sitter Metric and Inertial Beltrami Coordinates
Under consideration of coordinate conditions, we get the
Schwarzschild-Beltrami-de Sitter (S-BdS) metric solution of the Einstein field
equations with a cosmological constant . A brief review to the de
Sitter invariant special relativity (dS-SR), and de Sitter general relativity
(dS-GR, or GR with a ) is presented. The Beltrami metric
provides inertial reference frame for the dS-spacetime. By examining the
Schwarzschild-de Sitter (S-dS) metric existed in literatures
since 1918, we find that the existed S-dS metric describes
some mixing effects of gravity and inertial-force, instead of a pure gravity
effect arisen from "solar mass" in dS-GR. In this paper, we solve the
vacuum Einstein equation of dS-GR, with the requirement of gravity-free metric
. In this way we find S-BdS
solution of dS-GR, written in inertial Beltrami coordinates. This is a new form
of S-dS metric. Its physical meaning and possible applications are discussed.Comment: 16 pages, 1 figur
The hidden treasure: four impressions by Charles T. Griffes
In the second half of the 19th century, Wagner awakened the world with his yearning opening motif in his music drama Tristan und Isolde which directly stimulated the blossoming of literature and music. Educated in Germany at fin de siècle, Charles Tomlinson Griffes (1884-1920) was an American composer whose works are saturated with the changing current of compositional methods. While Griffes is remembered primarily as an American Impressionist through his orchestral works, his art songs follow in the footsteps of the three Lieder giants, embrace the mythical and philosophical effects of Wagner’s music dramas, and infuse all these influences with a responsiveness and complete understanding of the musical languages. This document discusses the personal influences on Griffes’s art songs, theoretical connections to the three Lieder giants, aesthetic parallels between Griffes and Oscar Wilde, and highlights the melodic, rhythmic, and harmonic Wagnerian influences on Griffes’s Four Impressions. A hidden treasure, this study strives to cast light on the work, illuminate the interpretation of the song cycle, and support musicians in the preparation for an informed performance
What Factors Satisfy E-Book Platform Customers? Development of A Model to Evaluate E-Book User Behavior and Satisfaction
The use of e-book readers has become increasingly widespread; however, there are few studies to evaluate e-book user behavior and satisfaction on e-book platforms, and even fewer approaches the subject from the perspective of task-technology fit. In order to fill this gap, this study adopts task-technology fit theory to explore the factors that affect the behavior satisfaction of users on commercial e-book platforms. Our research model excludes utility and performance from task-technology fit theory to focus on individual user satisfaction measurement because general e-book platform users are not concerned about work performance issues in leisure activities. The results show that functional service, convenience, and searching task are important factors that influence users\u27 task-technology fit behavior. Moreover, task-technology fit may improve users\u27 satisfaction, flow and scanpath. Finally, satisfaction is affected by task-technology fit and flow factors. An analysis of the research explained 61 percent of the variance in users’ task-technology fit, and 59 percent of the variance in satisfaction to use e-book platform. These results provide a new perspective to e-book researchers and can help e-book platform managers and designers in making policies and designing platforms
Bacteria in the apical root canals of teeth with apical periodontitis
Background/PurposeBacteria in the tooth root canal may cause apical periodontitis. This study examined the bacterial species present in the apical root canal of teeth with apical periodontitis. Antibiotic sensitivity tests were performed to evaluate whether these identified bacterial species were susceptible to specific kinds of antibiotics.MethodsSelective media plating and biochemical tests were used first to detect the bacterial species in samples taken from the apical portion of root canals of 62 teeth with apical periodontitis. The isolated bacterial species were further confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry.ResultsWe found concomitant presence of two (32 teeth) or three species (18 teeth) of bacteria in 50 (80.6%) out of 62 tested teeth. However, only 34 bacterial species were identified. Of a total of 118 bacterial isolates (83 anaerobes and 35 aerobes), Prophyromonas endodontalis was detected in 10; Bacteroides, Dialister invisus or Fusobacterium nucleatum in 9; Treponema denticola or Enterococcus faecalis in 8; Peptostreptococcus or Olsenella uli in 6; and Veillonella in 5 teeth. The other 25 bacterial species were detected in fewer than five teeth. Approximately 80–95% of bacterial isolates of anaerobes were sensitive to ampicillin/sulbactam (Unasyn), amoxicillin/clavulanate (Augmentin), cefoxitin, and clindamycin. For E. faecalis, 85–90% of bacterial isolates were sensitive to gentamicin and linezolid.ConclusionRoot canal infections are usually caused by a mixture of two or three species of bacteria. Specific kinds of antibiotic can be selected to control these bacterial infections after antibiotic sensitivity testing
The Relationship Between Information Transparency And The Informativeness Of Accounting Earnings
The issue of corporate governance has prompted calls for greater transparency and disclosure on companies around the world. As a result, a disclosure ranking system, Information Transparency and Disclosure Ranking System (ITDRS) was launched in Taiwan since 2003 by the request of Taiwan Stock Exchange Corporation (TSEC). This paper examines the relationship between information transparency and the informativeness of accounting earnings. The empirical tests are conducted using TEJ database for firms listed on the Taiwan Stock Exchange with fiscal year ends between 2003 and 2004. Empirical results indicate that, information transparency, measured by the ranking of ITDRS, reduces the informativeness of accounting earnings. However, if information transparency is measured by the ratio of long-term investment in stocks, evidences show higher earnings response coefficients (ERC) for the more transparent firms. The results suggest that accounting numbers are more useful or valuable than the ITDRS ranking results from investors’ perspective. It also suggests that the ITDRS may be not a good proxy for financial transparency
Regulator of the mucoid phenotype A gene increases the virulent ability of extended-spectrum beta-lactamase-producing serotype non-K1/K2 Klebsiella pneumonia
BackgroundTo determine whether the presence of a capsule regulator gene [i.e., regulator of mucoid phenotype A (rmpA) gene] contributes to virulence on extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) with serotype non-K1/K2 strains.MethodsTwenty-eight ESBL-KP and non-ESBL-KP isolates were collected from the Tri-Service General Hospital (Taipei, Taiwan). The impact of the virulent rmpA gene in different capsular polysaccharide serotypes on ESBL-KP and non-ESBL-KP isolates was studied by a neutrophil phagocytosis reaction, a serum bactericidal assay, and an animal survival model.ResultsResistance to broad spectrum antibiotics was more prevalent in ESBL-KP strains than in non-ESBL-KP strains (p < 0.01). The ESBL-KP strains had different molecular patterns from non-ESBL-KP strains, based on pulsed-field gel electrophoresis. The frequency of serum-resistant isolates was the highest among ESBL-KP strains with rmpA (i.e., rmpA+) [71.4% (5/7)] than among of non-ESBL-KP rmpA+ strains [42.8% (6/14)], ESBL-KP strains without rmpA (rmpA−) [33.3% (7/21)], and non-ESBL-KP rmpA− strains [14.2% (2/14)]. The most significant increase in neutrophil resistance occurred in the ESBL-KP rmpA+ strains in comparison to the non-ESBL-KP rmpA+, ESBL-KP rmpA−, and non-ESBL-KP rmpA− strains (p < 0.01). The results of the animal survival model were compatible with the neutrophil phagocytosis reaction and serum bactericidal assay.ConclusionWe conclude that the pathogenic potential is greater in rmpA+ ESBL-KP strains than in rmpA– ESBL-KP and non-ESBL-KP strains
The Relationship between Coenzyme Q10, Oxidative Stress, and Antioxidant Enzymes Activities and Coronary Artery Disease
A higher oxidative stress may contribute to the pathogenesis of coronary artery disease (CAD). The purpose of this study was to investigate the relationship between coenzyme Q10 concentration and lipid peroxidation, antioxidant enzymes activities and the risk of CAD. Patients who were identified by cardiac catheterization as having at least 50% stenosis of one major coronary artery were assigned to the case group (n = 51). The control group (n = 102) comprised healthy individuals with normal blood biochemical values. The plasma coenzyme Q10, malondialdehyde (MDA) and antioxidant enzymes activities (catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx)) were measured. Subjects with CAD had significant lower plasma coenzyme Q10, CAT and GPx activities and higher MDA and SOD levels compared to those of the control group. The plasma coenzyme Q10 was positively correlated with CAT and GPx activities and negatively correlated with MDA and SOD. However, the correlations were not significant after adjusting for the potential confounders of CAD with the exception of SOD. A higher level of plasma coenzyme Q10 (≥0.52 μmol/L) was significantly associated with reducing the risk of CAD. Our results support the potential cardioprotective impact of coenzyme Q10
The Complete Chloroplast Genome of Ginkgo biloba Reveals the Mechanism of Inverted Repeat Contraction
We determined the complete chloroplast genome (cpDNA) of Ginkgo biloba (common name: ginkgo), the only relict of ginkgophytes from the Triassic Period. The cpDNA molecule of ginkgo is quadripartite and circular, with a length of 156,945 bp, which is 6,458 bp shorter than that of Cycas taitungensis. In ginkgo cpDNA, rpl23 becomes pseudo, only one copy of ycf2 is retained, and there are at least five editing sites. We propose that the retained ycf2 is a duplicate of the ancestral ycf2, and the ancestral one has been lost from the inverted repeat A (IRA). This loss event should have occurred and led to the contraction of IRs after ginkgos diverged from other gymnosperms. A novel cluster of three transfer RNA (tRNA) genes, trnY-AUA, trnC-ACA, and trnSeC-UCA, was predicted to be located between trnC-GCA and rpoB of the large single-copy region. Our phylogenetic analysis strongly suggests that the three predicted tRNA genes are duplicates of trnC-GCA. Interestingly, in ginkgo cpDNA, the loss of one ycf2 copy does not significantly elevate the synonymous rate (Ks) of the retained copy, which disagrees with the view of Perry and Wolfe (2002) that one of the two-copy genes is subjected to elevated Ks when its counterpart has been lost. We hypothesize that the loss of one ycf2 is likely recent, and therefore, the acquired Ks of the retained copy is low. Our data reveal that ginkgo possesses several unique features that contribute to our understanding of the cpDNA evolution in seed plants
Effects of natto extract on endothelial injury in a rat model
Vascular endothelial damage has been found to be associated with thrombus formation, which is considered to be a risk factor for cardiovascular disease. A diet of natto leads to a low prevalence of cardiovascular disease. The aim of the present study was to investigate the effects of natto extract on vascular endothelia damage with exposure to laser irradiation. Endothelial damage both in vitro and in vivo was induced by irradiation of rose bengal using a DPSS green laser. Cell viability was determined by MTS assay, and the intimal thickening was verified by a histological approach. The antioxidant content of natto extract was determined for the free radical scavenging activity. Endothelial cells were injured in the presence of rose bengal irradiated in a dose-dependent manner. Natto extract exhibits high levels of antioxidant activity compared with purified natto kinase. Apoptosis of laser-injured endothelial cells was significantly reduced in the presence of natto extract. Both the natto extract and natto kinase suppressed intimal thickening in rats with endothelial injury. The present findings suggest that natto extract suppresses vessel thickening as a synergic effect attributed to its antioxidant and anti-apoptosis properties
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