3,323 research outputs found
Geometric Asian option: Geometric Ornstein-Uhlenbeck process
Asian options, also known as average value options, are exotic options whose payoffs are dependent on the average prices of the underlying assets over the life of the options. The Asian options are very popular among the market participants when dealing with thinly traded commodities because the average property of the Asian options makes it very difficult to manipulate the payoffs of the options. Another reason for the popularity of Asian options is that they are cheaper than the corresponding portfolio of standard options to hedge the same exposure. The pricing of Asian options has been the subject of continuous studies. In previous studies, Asian options have been priced based on the assumption that the underlying asset follows a geometric Brownian motion. This dissertation, however, assumes that the underlying asset follows a geometric Ornstein-Uhlenbeck process and provides an explicit formula for the geometric Asian options. The geometric Ornstein-Uhlenbeck process is more economically appropriate than the geometric Brownian motion for modelling commodity prices, exchange rates and interest rates due to its mean-reverting property
Elevation of High-Mobility Group Protein Box-1 in Serum Correlates with Severity of Acute Intracerebral Hemorrhage
High-mobility group protein box-1 (HMGB1) is a proinflammatory involved in many inflammatory diseases. However, its roles in intracerebral hemorrhage (ICH) remain unknown. The purpose of this study was to examine the correlation between changes in serum levels of HMGB1 following acute ICH and the severity of stroke as well as the underlying mechanism. Changes in serum levels of HMGB1 in 60 consecutive patients with primary hemispheric ICH within 12 hours of onset of symptoms were determined. The correlation of HMGB1 with disease severity, IL-6, and TNF-α was analyzed. Changes in HMGB1 levels were detected with ELISA and Western blot. Compared with normal controls, patients with ICH had markedly elevated levels of HMGB1, which was significantly correlated with the levels of IL-6 and TNF-α, NIHSS score at the 10th day, and mRS score at 3 months. In comparison with the control group, the levels of HMGB1 in the perihematomal tissue in mice with ICH increased dramatically, peaked at 72 hours, and decreased at 5 days. Meanwhile, heme could stimulate cultured microglia to release large amounts of HMGB1 whereas Fe2+/3+ ions failed to stimulate HMGB1 production from microglia. Our findings suggest that HMGB1 may play an essential role in the ICH-caused inflammatory injury
Stunting and soil-transmitted-helminth infections among school-age pupils in rural areas of southern China
<p>Abstract</p> <p>Background</p> <p>Stunting and soil-transmitted helminth (STH) infections including ascariasis, trichuriasis and hookworm remain major public health problems in school-age pupils in developing countries. The objectives of this study were to determine the prevalence of stunting for children and its association with three major soil-transmitted helminths (STH) in rural areas of southern China. The study also aims to determine risk factors for stunting and to provide guidance on the prevention and control of stunting and STH infections for future studies in this field.</p> <p>Results</p> <p>A cross-sectional survey was carried out in the poor rural areas in Guangxi Autonomous Regional and Hainan Province where STH prevalence was higher between September and November 2009. Pupils were from 15 primary schools. All the school-age pupils aged between 9 and 12 years old (mean age 11.2 ± 3.2 years), from grades three to six took part in this study. Study contents include questionnaire surveys, physical examination and laboratory methods (stool checking for eggs of three major STH infections and haemoglobin determination was performed for the anaemia test). Finally 1031 school-age pupils took part in survey. The results showed that the overall prevalence of stunting (HAZ < 2SD) was 25.6%, based on the WHO Child Growth Standards (2007). Risk factors for stunting based on logistic regression analyses were: (1) STH moderate-to-heavy intensity infections (OR = 1.93;95%CI:1.19,3.11); (2) anaemia (OR = 3.26;95%CI: 2.02,5.27); (3) education level of mother (OR = 2.13; 95%CI: 1.39,3.25). The overall prevalence of major STH infections was 36.7%, STH moderate-to-heavy intensity infections was 16.7%. The overall prevalence of ascariasis, trichuriasis, hookworm and co-infection were 18.5%, 11.2%, 14.7% and 9.1% respectively. The prevalence of anaemic children (HB < 12 g/dl) was 13.1%.</p> <p>Conclusion</p> <p>The present study showed that stunting was highly prevalent among the study population and STH infection is one of the important risk factors for stunting, with moderate-to-heavy intensity infections being the main predictor of stunting. Hence, additional interventions measures such as to promote de-worming treatment, to enhance health education and to improve hygiene and sanitation in order to reduce stunting in this population, are needed throughout the primary school age group.</p
Multiple Unpinned Dirac Points in Group-Va Single-layers with Phosphorene Structure
Emergent Dirac fermion states underlie many intriguing properties of
graphene, and the search for them constitute one strong motivation to explore
two-dimensional (2D) allotropes of other elements. Phosphorene, the ultrathin
layers of black phosphorous, has been a subject of intense investigations
recently, and it was found that other group-Va elements could also form 2D
layers with similar puckered lattice structure. Here, by a close examination of
their electronic band structure evolution, we discover two types of Dirac
fermion states emerging in the low-energy spectrum. One pair of (type-I) Dirac
points is sitting on high-symmetry lines, while two pairs of (type-II) Dirac
points are located at generic -points, with different anisotropic
dispersions determined by the reduced symmetries at their locations. Such
fully-unpinned (type-II) 2D Dirac points are discovered for the first time. In
the absence of spin-orbit coupling, we find that each Dirac node is protected
by the sublattice symmetry from gap opening, which is in turn ensured by any
one of three point group symmetries. The spin-orbit coupling generally gaps the
Dirac nodes, and for the type-I case, this drives the system into a quantum
spin Hall insulator phase. We suggest possible ways to realize the unpinned
Dirac points in strained phosphorene.Comment: 30 pages, 6 figure
Predictive value of CpG island methylator phenotype for tumor recurrence in hepatitis B virus-associated hepatocellular carcinoma following liver transplantation
<p>Abstract</p> <p>Background</p> <p>CpG island methylator phenotype (CIMP), in which multiple genes concordantly methylated, has been demonstrated to be associated with progression, recurrence, as well as overall survival in some types of cancer.</p> <p>Methods</p> <p>We examined the promoter methylation status of seven genes including <it>P16, CDH1, GSTP1, DAPK, XAF1, SOCS1 </it>and <it>SYK </it>in 65 cases of HCC treated with LT by methylation-specific PCR. CIMP+ was defined as having three or more genes that are concordantly methylated. The relationship between CIMP status and clinicopathological parameters, as well as tumor recurrence was further analyzed.</p> <p>Results</p> <p>CIMP+ was more frequent in HCC with AFP > 400 ng/ml than those with AFP ≤ 400 ng/ml (<it>P </it>= 0.017). In addition, patients with CIMP+ were prone to have multiple tumor numbers than those with CIMP- (<it>P </it>= 0.007). Patients with CIMP+ tumors had significantly worse recurrence-free survival (RFS) than patients with CIMP-tumors by Kaplan-Meier estimates (<it>P </it>= 0.004). Multivariate analysis also revealed that CIMP status might be a novel independent prognostic factor of RFS for HCC patients treated with LT (HR: 3.581; 95% CI: 1.473-8.710, <it>P </it>= 0.005).</p> <p>Conclusion</p> <p>Our results suggested that CIMP could serve as a new prognostic biomarker to predict the risk of tumor recurrence in HCC after transplantation.</p
Learning Disentangled Feature Representation for Hybrid-distorted Image Restoration
Hybrid-distorted image restoration (HD-IR) is dedicated to restore real
distorted image that is degraded by multiple distortions. Existing HD-IR
approaches usually ignore the inherent interference among hybrid distortions
which compromises the restoration performance. To decompose such interference,
we introduce the concept of Disentangled Feature Learning to achieve the
feature-level divide-and-conquer of hybrid distortions. Specifically, we
propose the feature disentanglement module (FDM) to distribute feature
representations of different distortions into different channels by revising
gain-control-based normalization. We also propose a feature aggregation module
(FAM) with channel-wise attention to adaptively filter out the distortion
representations and aggregate useful content information from different
channels for the construction of raw image. The effectiveness of the proposed
scheme is verified by visualizing the correlation matrix of features and
channel responses of different distortions. Extensive experimental results also
prove superior performance of our approach compared with the latest HD-IR
schemes.Comment: Accepted by ECCV202
PO-165 Effects of Living-High Training-Low on HIF-1α Transcriptional Regulatory Factors MAPKs mRNA in Gastrocnemius of Rats
Objective To evaluate the effects of Living-High Training-Low on HIF-1α transcriptional regulatory factors MAPKs mRNA in gastrocnemius of Rats.
Methods After adaptive training, 40 8-weeks-old male SD rats were divided into living-low quiet control group (LC), living-low training-low group (LoLo), living-high quiet control group (HC), living-high training-low group (HiLo). All living-high groups stayed in the environment with 13.6% oxygen concentration, about altitude of 3500 m, for 12h/day. All training groups underwent treadmill training with 35m/min for 1hour/day, 5days/week. 4 weeks later, the gastrocnemius was sampled 24 hours after the last training. The ERK, p38MAPK, JNK and HIF-1α mRNA genes expressions in gastrocnemius were measured by real-time quantitative PCR.
Results The gastrocnemius ERK mRNA of HiLo group was significantly higher than LC (P<0.01), LoLo and HC groups (P<0.05). The p38MAPK mRNA of HiLo group was significantly higher than LC and LoLo groups (P<0.01 and P<0.05), and there was no significant difference between HiLo and HC group (P>0.05). The JNK and HIF-1α mRNA of HiLo group were significantly higher than other groups (P<0.01).
Conclusions Living-High Training-Low significantly raise ERK、p38MAPK、JNK and HIF-1α gene expression in gastrocnemius of Rats. ERK, p38MAPK and JNK may be one of the transcription factors regulating HIF-1α mRNA expression in Living-High Training-Low in gastrocnemius of Rats
Determination of DQ-798 in rat plasma by UHPLC-MS/MS and its application to a pharmacokinetic study
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