4,159 research outputs found
Exchange Rate Pass-through and Industry Characteristics: The Case of Taiwan's Exports of Midstream Petrochemical Products
Based on 1986-1992 survey data of 22 midstream petrochemical industries in Taiwan, the empirical results of the export price, the markup ratio and the price-cost margin equations in this study show that Taiwan's petrochemical firms absorb only a small portion of a given weighted exchange rate change in their export prices, markup ratios and price-cost margins. It implies that Taiwan's petrochemical firms have a weak pricing-to-market pattern. The empirical results may be explained by the volatility of profitability, high market concentration and small export/domestic production share. However, the impacts of the exchange rate change on the export price, markup ratio and price-cost margin have a tendency to increase during the period of 1987" to 1992. The tendency might be attributed to increasing competition of the petrochemical markets in the world, or Taiwanese firms' gradual realization of the importance of holding their world market shares in response to the exchange rate change.
Trade in Services in the Asia Pacific Region, NBER East Asia Seminar on Economics (EASE), Volume 11
Gene Regulatory Network Reconstruction Using Conditional Mutual Information
<p/> <p>The inference of gene regulatory network from expression data is an important area of research that provides insight to the inner workings of a biological system. The relevance-network-based approaches provide a simple and easily-scalable solution to the understanding of interaction between genes. Up until now, most works based on relevance network focus on the discovery of direct regulation using correlation coefficient or mutual information. However, some of the more complicated interactions such as interactive regulation and coregulation are not easily detected. In this work, we propose a relevance network model for gene regulatory network inference which employs both mutual information and conditional mutual information to determine the interactions between genes. For this purpose, we propose a conditional mutual information estimator based on adaptive partitioning which allows us to condition on both discrete and continuous random variables. We provide experimental results that demonstrate that the proposed regulatory network inference algorithm can provide better performance when the target network contains coregulated and interactively regulated genes.</p
Research on the Architecture Model of Volatile Data Forensics
AbstractThis paper proposed a new architecture model of volatile data forensic. The model applied to all the volatile data sources is a general model. It can rebuild the evidence data fragment to chains of evidence which contains the behavior characteristics, so as to assist investigators to do case analysis. With the accumulated experience, the model can help judicial officers to intelligently analyze the same type of computer crimes, and based on currently available information to predict the impending crimes
Robust discovery of periodically expressed genes using the laplace periodogram
<p>Abstract</p> <p>Background</p> <p>Time-course gene expression analysis has become important in recent developments due to the increasingly available experimental data. The detection of genes that are periodically expressed is an important step which allows us to study the regulatory mechanisms associated with the cell cycle.</p> <p>Results</p> <p>In this work, we present the Laplace periodogram which employs the least absolute deviation criterion to provide a more robust detection of periodic gene expression in the presence of outliers. The Laplace periodogram is shown to perform comparably to existing methods for the <it>Sacharomyces cerevisiae</it> and <it>Arabidopsis</it> time-course datasets, and to outperform existing methods when outliers are present.</p> <p>Conclusion</p> <p>Time-course gene expression data are often noisy due to the limitations of current technology, and may include outliers. These artifacts corrupt the available data and make the detection of periodicity difficult in many cases. The Laplace periodogram is shown to perform well for both data with and without the presence of outliers, and also for data that are non-uniformly sampled.</p
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
Understorey plant community and light availability in conifer plantations and natural hardwood forests in Taiwan
Questions: What are the effects of replacing mixed species natural forests with Cryptomeria japonica plantations on understorey plant functional and species diversity? What is the role of the understorey light environment in determining understorey diversity and community in the two types of forest?
Location: Subtropical northeast Taiwan.
Methods: We examined light environments using hemispherical photography, and diversity and composition of understorey plants of a 35âyr C. japonica plantation and an adjacent natural hardwood forest.
Results: Understorey plant species richness was similar in the two forests, but the communities were different; only 18 of the 91 recorded understorey plant species occurred in both forests. Relative abundance of plants among different functional groups differed between the two forests. Relative numbers of shadeâtolerant and shadeâintolerant seedling individuals were also different between the two forest types with only one shadeâintolerant seedling in the plantation compared to 23 seedlings belonging to two species in the natural forest. In the natural forest 11 species of tree seedling were found, while in the plantation only five were found, and the seedling density was only one third of that in the natural forest. Across plots in both forests, understorey plant richness and diversity were negatively correlated with direct sunlight but not indirect sunlight, possibly because direct light plays a more important role in understorey plant growth.
Conclusions: We report lower species and functional diversity and higher light availability in a natural hardwood forest than an adjacent 30âyr C. japonica plantation, possibly due to the increased dominance of shadeâintolerant species associated with higher light availability. To maintain plant diversity, management efforts must be made to prevent localized losses of shadeâadapted understorey plants
The role of cytochrome c oxidase subunit Va in non-small cell lung carcinoma cells: association with migration, invasion and prediction of distant metastasis
BACKGROUND: Lung cancer is one of the most lethal malignancies worldwide, but useful biomarkers of lung cancer are still insufficient. The aim of this study is to identify some membrane-bound protein(s) associated with migration and invasion in human non-small cell lung cancer (NSCLC) cells. METHODS: We classified four NSCLC cell lines into high and low migration/invasion groups by Transwell and Matrigel assays. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), we identified 10 membrane-associated proteins being significantly overexpressed in the high migration/invasion group. The expression of the target protein in the four NSCLC cell lines was then confirmed by reverse transcription polymerase chain reaction (RT-PCR), western blot and immunostaining. RNA interference technique was applied to observe the influence of the target protein on migration and invasion. Gelatin zymography was also performed to evaluate the activities of matrix metalloproteinase (MMP)-2 and MMP-9. Expression condition of the target protein on surgical specimens was further examined by immunohistochemical staining and the clinicopathologic data were analyzed. RESULTS: We identified a mitochondria-bound protein cytochrome c oxidase subunit Va (COX Va) because of its abundant presence found exclusively in tumorous areas. We also demonstrated that migration and invasion of NSCLC cells decreased substantially after knocking down COX Va by siRNA. Meanwhile, we found a positive correlation between COX Va expression, Bcl-2 expression and activities of MMP-2 and MMP-9 in NSCLC cells. Immunohistochemical staining of surgically resected lung adenocarcinomas in 250 consecutive patients revealed that strong COX Va expression was found in 54.8% (137/250) of patients and correlated positively with the status of lymph node metastasis (Pâ=â0.032). Furthermore, strong COX Va expression was associated with the presence of distant metastasis (Pâ=â0.033). CONCLUSIONS: Our current study showed that COX Va may play a role in migration and invasion of NSCLC cells and can be used as a biomarker to predict aggressiveness of NSCLC
Colchicine protects against acute pancreatitis via downregulation of cytokine levels
Purpose: To investigate the effect of colchicine on acute pancreatitis (AP) in a rat model, and the molecular mechanism involved.
Methods: Acute pancreatitis (AP) was induced in rats by injection with 5 % sodium taurocholate. Changes in histology of pancreatic tissues were determined following treatment with colchicine. Serum amylase activity was measured using Automated Biochemistry Analyser.
Results: Hematoxylin and eosin (H & E) staining showed that colchicine prevented histopathological changes such as infiltration of interstitial leukocytes and erythrocytes, cell necrosis, oedema formation and vacuolization in the rat pancreas. Treatment of AP rats with colchicine significantly and dosedependently decreased ascite volume in the abdominal cavity. Serum amylase activity was significantly suppressed in AP rats on treatment with 100 mg/kg colchicine. Furthermore, treatment of the AP rats with colchicine caused marked decrease in the expressions of interleukin 6 and tumor necrosis factor α, and upregulated expressions of IL 10 in serum. Colchicine treatment of AP rats also caused significant increase in CGRP level in the plasma.
Conclusion: Colchicine prevents pancreatic tissue damage induced by AP by down-regulating proinflammatory cytokines, upregulation of anti-inflammatory cytokines, and enhancing CGRP release. Therefore, colchicine may be useful for the treatment of acute pancreatitis
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