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Search Results: 1 - 10 of 4290 matches for " Anders Leung "
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Constrained Wiener Processes and Their Financial Applications  [PDF]
Andrew Leung
Journal of Mathematical Finance (JMF) , 2018, DOI: 10.4236/jmf.2018.84043
Abstract: The extrema of Wiener processes are relevant to the pricing of so-called exotic options, which have many financial applications. The probability densities of such extrema are well known for one dimensional Wiener processes. We employ elementary methods to derive analytical expressions for the densities for multidimensional Wiener processes, with multiple extrema. These take the form of (possibly infinite) series expansions of Gaussian densities. This is undertaken using the characterization of the Wiener process by the heat equation, a well known connection in mathematical physics.
Immunopathogenesis of Severe Acute Respiratory Disease in Zaire ebolavirus-Infected Pigs
Charles K. Nfon, Anders Leung, Greg Smith, Carissa Embury-Hyatt, Gary Kobinger, Hana M. Weingartl
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061904
Abstract: Ebola viruses (EBOV) are filamentous single-stranded RNA viruses of the family Filoviridae. Zaire ebolavirus (ZEBOV) causes severe haemorrhagic fever in humans, great apes and non-human primates (NHPs) with high fatality rates. In contrast, Reston ebolavirus (REBOV), the only species found outside Africa, is lethal to some NHPs but has never been linked to clinical disease in humans despite documented exposure. REBOV was isolated from pigs in the Philippines and subsequent experiments confirmed the susceptibility of pigs to both REBOV and ZEBOV with predilection for the lungs. However, only ZEBOV caused severe lung pathology in 5–6 weeks old pigs leading to respiratory distress. To further elucidate the mechanisms for lung pathology, microarray analysis of changes in gene expression was performed on lung tissue from ZEBOV-infected pigs. Furthermore, systemic effects were monitored by looking at changes in peripheral blood leukocyte subsets and systemic cytokine responses. Following oro-nasal challenge, ZEBOV replicated mainly in the respiratory tract, causing severe inflammation of the lungs and consequently rapid and difficult breathing. Neutrophils and macrophages infiltrated the lungs but only the latter were positive for ZEBOV antigen. Genes for proinflammatory cytokines, chemokines and acute phase proteins, known to attract immune cells to sites of infection, were upregulated in the lungs, causing the heavy influx of cells into this site. Systemic effects included a decline in the proportion of monocyte/dendritic and B cells and a mild proinflammatory cytokine response. Serum IgM was detected on day 5 and 6 post infection. In conclusion, a dysregulation/over-activation of the pulmonary proinflammatory response may play a crucial role in the pathogenesis of ZEBOV infection in 5–6 weeks old pigs by attracting inflammatory cells to the lungs.
Ocular and Extraocular Expression of Opsins in the Rhopalium of Tripedalia cystophora (Cnidaria: Cubozoa)
Jan Bielecki, Alexander K. Zaharoff, Nicole Y. Leung, Anders Garm, Todd H. Oakley
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098870
Abstract: A growing body of work on the neuroethology of cubozoans is based largely on the capabilities of the photoreceptive tissues, and it is important to determine the molecular basis of their light sensitivity. The cubozoans rely on 24 special purpose eyes to extract specific information from a complex visual scene to guide their behavior in the habitat. The lens eyes are the most studied photoreceptive structures, and the phototransduction in the photoreceptor cells is based on light sensitive opsin molecules. Opsins are photosensitive transmembrane proteins associated with photoreceptors in eyes, and the amino acid sequence of the opsins determines the spectral properties of the photoreceptors. Here we show that two distinct opsins (Tripedalia cystophora-lens eye expressed opsin and Tripedalia cystophora-neuropil expressed opsin, or Tc-leo and Tc-neo) are expressed in the Tripedalia cystophora rhopalium. Quantitative PCR determined the level of expression of the two opsins, and we found Tc-leo to have a higher amount of expression than Tc-neo. In situ hybridization located Tc-leo expression in the retinal photoreceptors of the lens eyes where the opsin is involved in image formation. Tc-neo is expressed in a confined part of the neuropil and is probably involved in extraocular light sensation, presumably in relation to diurnal activity.
Cycling as Innovation in Norway and Sweden—A Narrative Study of the Acceptance of a Technical Novelty  [PDF]
Anders Gustavsson
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.21009
Abstract: This paper deals with the acceptance of a technical novelty, in this case cycling, during the late nineteenth and early twentieth century. Experiences and feelings are the focus. The analytical perspectives are: social status, economy, age, gender, work/leisure, safety/danger. The innovation process of cycling conducted by a contrast between two neighbouring countries of Norway and Sweden respectively. The oral source material is found in Norwegian and Swedish folklore archives. The earliest design of bicycle was called velocipede. The bicycles began to appear around 1900. The first owners of bicycles were mostly well-to-do people in both rural and urban areas. As long as there was a shortage of bicycles, a certain collegiality existed, which implied that several people could use the same
Swedish Belief Narratives on Afterlife Earlier and Today  [PDF]
Anders Gustavsson
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.211026
Abstract: My aim is to examine afterlife beliefs in Sweden, partly from the late 1800s and the early 1900s, partly from the 2000s. It will be a contrastive study of two different periods and not a diachronic study of developments across a continuous stretch of time. Since this is a study of popular beliefs, ordinary people are in the center. My research questions are: What types of popular beliefs can be traced in the pre-industrial society? What types of beliefs are characteristic of the present-day society? Which differences and similarities can be found in belief narratives of these periods? How can scholars get information about belief in afterlife in older times and nowadays? In the 1800s this is documented through narratives in folklore archives and inscriptions on grave memorials, nowadays—by means of memorial websites on the Internet.
Traditional Chinese Medicine in orthopaedics—Problems and future direction  [PDF]
Ping-Chung Leung
Open Journal of Therapy and Rehabilitation (OJTR) , 2014, DOI: 10.4236/ojtr.2014.21001
Abstract: Introduction: Orthopaedic surgery includes varieties of injuries and other pathologies. Treatments are complicated while healing and recovery take time. Rehabilitation needs planning and commitment. In the Chinese Communities, traditional medicine has been popular since hundreds of years ago and has remained so in spite of the current advances in medicine. The purpose of this review is to identify the techniques being used in current situations, the indications and problems. Varieties of Traditional Treatments: 1) Topical applications of herbs are very much welcome after joint sprains, inflammatory conditions and even fractures. 2) On the wide area of physical training, the Chinese Tai-chi and Qigong are excellent gentle exercises for personal pursues. These exercises emphasize on body-mind interactions and carry strong philosophical insights. 3) Acupuncture has become standard rehabilitation practice in some hospitals and is getting even more popular in pain control and rehabilitation training after nerve injuries. Problems: Topical agents for pain and inflammation are not totally safe because allergic adverse conditions could happen from time to time. The major concern could be the unawareness of non-unions or delayed unions in fracture cases after herbal applications because the traditional healers are using too little modern assessment tools. Physical trainings and acupunctures are on the whole safe, only that indications are not clearly defined. Future Direction: 1) Concerning the topical agents used for pain and swelling, the essential research requirements include demonstration on the topical agents’ anti inflammatory, angiogenic and cell regenerative effects. The capability of skin penetration needs to be confirmed and a final clinical trial will further confirm the efficacy. 2) Clinical researches trying to obtain evidence on the use of Tai-chi and Qigong on the neuromuscular recovery are plentiful, while their effects on cardiovascular and respiratory health are likewise encouraging. 3) Acupuncture has already become a standard treatment option for pain control, nausea/vomiting and neuromuscular recoveries.
Schur Complement Computations in Intel? Math Kernel Library PARDISO  [PDF]
Alexander Kalinkin, Anton Anders, Roman Anders
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.62028
Abstract: This paper describes a method of calculating the Schur complement of a sparse positive definite matrix A. The main idea of this approach is to represent matrix A in the form of an elimination tree using a reordering algorithm like METIS and putting columns/rows for which the Schur complement is needed into the top node of the elimination tree. Any problem with a degenerate part of the initial matrix can be resolved with the help of iterative refinement. The proposed approach is close to the “multifrontal” one which was implemented by Ian Duff and others in 1980s. Schur complement computations described in this paper are available in Intel® Math Kernel Library (Intel® MKL). In this paper we present the algorithm for Schur complement computations, experiments that demonstrate a negligible increase in the number of elements in the factored matrix, and comparison with existing alternatives.
Intel® Math Kernel Library PARDISO* for Intel® Xeon PhiTM Manycore Coprocessor  [PDF]
Alexander Kalinkin, Anton Anders, Roman Anders
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.68121
Abstract: The paper describes an efficient direct method to solve an equation Ax = b, where A is a sparse matrix, on the Intel® Xeon PhiTM coprocessor. The main challenge for such a system is how to engage all available threads (about 240) and how to reduce OpenMP* synchronization overhead, which is very expensive for hundreds of threads. The method consists of decomposing A into a product of lower-triangular, diagonal, and upper triangular matrices followed by solves of the resulting three subsystems. The main idea is based on the hybrid parallel algorithm used in the Intel® Math Kernel Library Parallel Direct Sparse Solver for Clusters [1]. Our implementation exploits a static scheduling algorithm during the factorization step to reduce OpenMP synchronization overhead. To effectively engage all available threads, a three-level approach of parallelization is used. Furthermore, we demonstrate that our implementation can perform up to 100 times better on factorization step and up to 65 times better in terms of overall performance on the 240 threads of the Intel® Xeon PhiTM coprocessor.
An Extension of Some Results Due to Cox and Leland  [PDF]
Andrew P. Leung, Wen Shi
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.34043
Abstract:

We investigate an optimal portfolio allocation problem between a risky and a risk-free asset, as in [1]. They obtained explicit conditions for path-independence and optimality of allocation strategies when the price of the risky asset follows a geometric Brownian motion with constant asset characteristics. This paper analyzes and extends their results for dynamic investment strategies by allowing for non-constant returns and volatility. We adopt a continuous-time approach and appeal to well established results in stochastic calculus for doing so.

Use of Lexical Stress during Oral Reading among Japanese EFL Learners  [PDF]
Lisa Yoshikawa, Chi Yui Leung
Open Journal of Modern Linguistics (OJML) , 2014, DOI: 10.4236/ojml.2014.45050
Abstract: The purpose of the present study is to examine second language (L2) oral reading with a focus on lexical stress. We conducted oral reading tasks to investigate whether 14 Japanese learners of English as a foreign language (EFL) read words aloud with different lexical stress (one- or two- stress words) with appropriate stress assignment, similar to a comparison group of 14 native English speakers, in order to see whether EFL learners, who have fewer verbal input and output opportunities, assign the proper stress(es) in oral reading contexts. The participants read 18 pairs of four-syllable one- and two-stress words both in isolation and in sentence context conditions, and the whole word duration, syllable duration, and syllable intensity were analyzed. The results showed that both groups of readers (1) read two-stress words longer than one-stress words and (2) read stressed syllables longer than unstressed syllables with appropriate stress assignment. Our findings suggest that intermediate EFL learners can recognize and manipulate L2 prosodic information, even though their L1 does not possess the property. Future directions for L2 oral reading research development are discussed.
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