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Search Results: 1 - 10 of 3499 matches for " Dung-Ching Perng "
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Non-contact monitoring of Ge and B diffusion in B-doped epitaxial Si1-xGex bi-layers on silicon substrates during rapid thermal annealing by multiwavelength Raman spectroscopy
Min-Hao Hong,Chun-Wei Chang,Dung-Ching Perng,Kuan-Ching Lee
AIP Advances , 2012, DOI: 10.1063/1.4748294
Abstract: B-doped, thin Si1-xGex bi-layers with different Ge content and B concentrations were epitaxially grown on Si(100) device wafers. Diffusion behavior of Ge and B atoms during rapid thermal annealing were monitored by multiwavelength micro-Raman spectroscopy. Raman spectra indicating possible Ge and B redistribution by thermal diffusion was observed from B-doped, thin Si1-xGex bi-layers on Si(100) wafers after rapid thermal annealing at 950°C or higher. Significant Ge and B diffusion in Si1-xGex bi-layers and Si substrates was verified by secondary ion mass spectroscopy. Pile up of B atoms at the surface and at the boundary between Si1-xGex bi-layers was observed in the early stages of thermal diffusion.
Aspergillus parasiticus crzA, Which Encodes Calcineurin Response Zinc-Finger Protein, Is Required for Aflatoxin Production under Calcium Stress
Perng-Kuang Chang
International Journal of Molecular Sciences , 2008, DOI: 10.3390/ijms9102027
Abstract: Two morphologically different Aspergillus parasiticus strains, one producing aflatoxins, abundant conidia but few sclerotia (BN9) and the other producing O-methylsterimatocystin (OMST), copious sclerotia but a low number of conidia (RH), were used to assess the role of crzA which encodes a putative calcium-signaling pathway regulatory protein. Under standard culture conditions, BN9ΔcrzA mutants conidiated normally but decreased slightly in radial growth, regardless of illumination conditions. RHΔcrzA mutants produced only conidia under light and showed decreased conidiation and delayed sclerotial formation in the dark. Regulation of conidiation of both A. parasiticus strains by light was independent of crzA. Increased concentrations of lithium, sodium, and potassium impaired conidiation and sclerotial formation of the RHΔcrzA mutants but they did not affect conidiation of the BN9ΔcrzA mutants. Vegetative growth and asexual development of both ΔcrzA mutants were hypersensitive to increased calcium concentrations. Calcium supplementation (10 mM) resulted in 3-fold and 2-fold decreases in the relative expression of the endoplasmic reticulum calcium ATPase 2 gene in the BN9 and RH parental strains, respectively, but changes in both ΔcrzA mutants were less significant. Compared to the parental strains, the ΔcrzA mutants barely produced aflatoxins or OMST after the calcium supplementation. The relative expression levels of aflatoxin biosynthesis genes, nor1, ver1, and omtA, in both ΔcrzA mutants were decreased significantly, but the decreases in the parental strains were at much lower extents. CrzA is required for growth and development and for aflatoxin biosynthesis under calcium stress conditions.
A short note on universality of some quadratic forms
Cherng-tiao Perng
International Mathematical Forum , 2013,
Abstract: In a paper by J. Deutsch [1], a quaternionic proof of the universalityof seven quaternary quadratic forms was given. The proof relieson a construction very similar to that of Hurwitz quaternions, and itsassociated division algorithm. Of course, these results are evident, ifone uses the Conway-Schneeberger Fifteen Theorem [2], as the authoralso mentioned, however it is interesting to give a direct proof for somespecific quadratic forms based on simple argument. It is the purposeof this short note to prove five of the seven quadratic forms mentionedand proven by Deutsch, using the universality of the classical quadraticform associated to the celebrated Lagrange’s Theorem of Four Squaresand Euler’s trick.
A simple computational approach to the fundamental theorem of asset pricing
Cherng-tiao Perng
Applied Mathematical Sciences , 2012,
Abstract:
On Conserved Quantities at Spatial Infinity
Shyan-Ming Perng
Physics , 1998, DOI: 10.1063/1.532841
Abstract: There is a well-known short list of asymptotic conserved quantities for a physical system at spatial infinity. We search for new ones.This is carried outwithin the asymptotic framework of Ashtekar and Romano, in which spatial infinity is represented as a smooth boundary of space-time. We first introduce, for physical fields on space-time,a characterization of their asymptotic behavior as certain fields on this boundary. Conserved quantities at spatial infinity, in turn, are constructed from these fields. We find,in Minkowski space-time, that each of a Klein-Gordon field, a Maxwell field, and a linearized gravitational field yields an entire hierarchy of conserved quantities. Only certain quantities in this hierarchy survive into curved space-time.
Spatial autocorrelation analysis of 13 leading malignant neoplasms in Taiwan: a comparison between the 1995-1998 and 2005-2008 periods  [PDF]
Pui-Jen Tsai, Cheng-Hwang Perng
Health (Health) , 2011, DOI: 10.4236/health.2011.312120
Abstract: Spatial autocorrelation methodologies, including Global Moran’s I and Local Indicators of Spatial Association statistic (LISA), were used to describe and map spatial clusters of 13 leading malignant neoplasms in Taiwan. A logistic regression fit model was also used to identify similar characteristics over time. Two time periods (1995-1998 and 2005-2008) were compared in an attempt to formulate common spatio-temporal risks. Spatial cluster patterns were identified using local spatial autocorrelation analysis. We found a significant spatio-temporal variation between the leading malignant neoplasms and well-documented spatial risk factors. For instance, in Taiwan, cancer of the oral cavity in males was found to be clustered in locations in central Taiwan, with distinct differences between the two time periods. Stomach cancer morbidity clustered in aboriginal townships, where the prevalence of Helicobacter pylori is high and even quite marked differences between the two time periods were found. A method which combines LISA statistics and logistic regression is an effective tool for the detection of space-time patterns with discontinuous data. Spatio-temporal mapping comparison helps to clarify issues such as the spatial aspects of both two time periods for leading malignant neoplasms. This helps planners to assess spatio-temporal risk factors, and to ascertain what would be the most advantageous types of health care policies for the planning and implementation of health care services. These issues can greatly affect the performance and effectiveness of health care services and also provide a clear outline for helping us to better understand the results in depth.
The Effect of Cold Temperature on Increased Exacerbation of Chronic Obstructive Pulmonary Disease: A Nationwide Study
Ching-Min Tseng, Yung-Tai Chen, Shuo-Ming Ou, Yi-Han Hsiao, Szu-Yuan Li, Shuu-Jiun Wang, Albert C. Yang, Tzeng-Ji Chen, Diahn-Warng Perng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057066
Abstract: Background Seasonal variations in the acute exacerbation of chronic obstructive pulmonary disease (COPD) have been reported. However, the influence of air temperature and other meteorological factors on COPD exacerbation remains unclear. Methods National Health Insurance registry data from January 1, 1999 to December 1, 2009 and meteorological variables from the Taiwan Central Weather Bureau for the same period were analyzed. A case-crossover study design was used to investigate the association between COPD exacerbation and meteorological variables. Results A total of 16,254 cases who suffered from COPD exacerbation were enrolled. We found that a 1°C decrease in air temperature was associated with a 0.8% increase in the exacerbation rate on event-days (95% confidence interval (CI), 1.015–1.138, p = 0.015). With a 5°C decrease in mean temperature, the cold temperature (28-day average temperature) had a long-term effect on the exacerbation of COPD (odds ratio (OR), 1.106, 95% CI 1.063–1.152, p<0.001). In addition, elderly patients and those who did not receive inhaled medication tended to suffer an exacerbation when the mean temperature dropped 5°C. Higher barometric pressure, more hours of sunshine, and lower humidity were associated with an increase in COPD exacerbation. Conclusions This study demonstrated the effect of cold temperatures on the COPD exacerbation rate. Elderly patients and those without inhaled medicine before the exacerbation event were affected significantly by lower mean temperatures. A more comprehensive program to prevent cold stress in COPD patients may lead to a reduction in the exacerbations rate of COPD.
A First Principles Simulation Framework for the Interactions between a Si(001) Surface and a Scanning Probe  [PDF]
Dung Q. Ly, Charalampos Makatsoris
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2012, DOI: 10.4236/jsemat.2012.223030
Abstract: By means of total energy calculations within the framework of the local density approximation (LDA), the interactions between a silicon Si(001) surface and a scanning probe are investigated. The tip of the probe, comprising 4 Si atoms scans along the dimer lines above an asymmetric p(2 × 1) surface, at a distance where the chemical interaction between tip-surface is dominant and responsible for image resolution. At that distance, the tip causes the dimer to toggle when it scans above the lower atom of a dimer. The toggled dimers create an alternating pattern, where the immediately adjacent neighbours of a toggled dimer remain unchanged. After the tip has fully scanned across the p(2 × 1) surface, causes the dimers to arrange in a p(2 × 2) reconstruction, reproducing the images obtained in scanning probe experiments. Our modelling methodology includes simulations that reveal the energy input required to overcome the barrier to the onset of dimer toggling. The results show that the energy input to overcome this barrier is lower for the p(2 × 1) surface than that for the p(2 × 2) or c(4 × 2) surfaces.
Household Savings and Productive Capital Formation in Rural Vietnam: Insurance vs. Social Network  [PDF]
Thomas Gries, Ha Van Dung
Modern Economy (ME) , 2014, DOI: 10.4236/me.2014.58081
Abstract:

In this paper, we investigate the role of the social network nexus and the insurance nexus in determining household savings and productive capital formation in rural Vietnam. We analyze the issue in two dimensions, stocks and flows, and consider the exposure to negative shocks. The instrumental variable method is employed and unlike previous studies, we account for the endogeneity of all concerned variables. The results indicate that the social network nexus has more impacts in “ex ante” rather than in “ex post” households. In both households groups, the effects of the insurance nexus dominate over those of the social network nexus. In the case of the stocks, we also find that the precautionary view holds in liquid assets but not in productive assets.

Deep Poisson Factorization Machines: factor analysis for mapping behaviors in journalist ecosystem
Pau Perng-Hwa Kung
Computer Science , 2015,
Abstract: Newsroom in online ecosystem is difficult to untangle. With prevalence of social media, interactions between journalists and individuals become visible, but lack of understanding to inner processing of information feedback loop in public sphere leave most journalists baffled. Can we provide an organized view to characterize journalist behaviors on individual level to know better of the ecosystem? To this end, I propose Poisson Factorization Machine (PFM), a Bayesian analogue to matrix factorization that assumes Poisson distribution for generative process. The model generalizes recent studies on Poisson Matrix Factorization to account temporal interaction which involves tensor-like structure, and label information. Two inference procedures are designed, one based on batch variational EM and another stochastic variational inference scheme that efficiently scales with data size. An important novelty in this note is that I show how to stack layers of PFM to introduce a deep architecture. This work discusses some potential results applying the model and explains how such latent factors may be useful for analyzing latent behaviors for data exploration.
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