Purebred or hybrid?: Reproducing the volatility in term structure dynamics

This paper investigates the ability of mixtures of affine, quadratic, and non-linear models to track the volatility in the term structure of interest rates. Term structure dynamics appear to exhibit pronounced time varying or stochastic volatility. Ahn et al. (Rev. Financial Stud. xx (2001) xxx) provide evidence suggesting that term structure models incorporating a set of quadratic factors are better able to reproduce term structure dynamics than affine models, although neither class of models is able to fully capture term structure volatility. In this study, we combine affine, quadratic and non-linear factors in order to maximize the ability of a term structure model to generate heteroskedastic volatility. We show that this combination entails a tradeoff between specification of heteroskedastic volatility and correlations among the factors. By combining factors, we are able to gauge the cost of this tradeoff. Using efficient method of moments (Gallant and Tauchen, Econometric Theory 12 (1996) 657), we find that augmenting a quadratic model with a non-linear factor results in improvement in fit over a model comprised solely of quadratic factors when the model only has to confront first and second moment dynamics. When the full dynamics are confronted, this result reverses. Since the non-linear factor is characterized by stronger dependence of volatility on the level of the factor, we conclude that flexibility in the specification of both level dependence and correlation structure of the factors are important for describing term structure dynamics

Elevated CO2 may alter pheromonal communication in Helicoverpa armigera (Lepidoptera: Noctuidae)

Carbon dioxide (CO2) as a greenhouse gas has been increasing in recent decades. Because an elevated atmospheric CO2 influences insect physiology and behaviour, we hypothesize that pheromone-mediated communication in the moth is affected by an increased CO2 level. We test the behavioural responses of male Helicoverpa armigera to sex pheromone in a wind tunnel, demonstrating a significant reduction of approaching behaviour to the odour source at a high CO2 level (1000ppm). Electroantennogram (EAG) responses of male to the pheromone component are also significantly suppressed in high CO2 environments (600 and 1000ppm), indicating that a high CO2 level inhibits both behavioural and electrophysiological responses of male to the sex pheromone. Interestingly, the EAG response of the whole head preparation of males is influenced more by the elevated CO2 level than that of the antenna-cut preparation. A sequential increase of CO2 levels from an ambient CO2 level also decreases the EAG response of the whole head but not of the labial palp-removed head, implying a potential mediation of labial palp in the head where the CO2 receptor is located. By contrast, sex pheromone production in females reared under or shifted to an elevated CO2 condition is increased, and the putative underlying mechanism for this is discussed. The present study provides an insight into the adaptive strategy of moth pheromone communication in a changing environment

Lysis of Microcystis aeruginosa with Extracts from Chinese Medicinal Herbs

Boiling water extracts of 66 selected Chinese medicinal herbs were screened for their anticyanobaterial activity against Microcystis aeruginosa by the soft-agar overlayer (SAO) method. Results indicated that extracts from 16 materials could inhibit the growth of this bacterial species. Among these anticyanobacterial samples, eight extracts showed low minimum inhibitory concentrations (MIC), including four extracts with MICs between 1 and 6 mg/mL, and four extracts with MICs < 1 mg/mL which could be considered useful to prevent the outbreak of cyanobacteria before the appearance of cyanobacterial blooms. Further study showed that three extracts with MIC values < 1 mg/mL induced intensive chlorophyll-a lysis within 7 days at the MIC. The results suggested that highly efficient anticyanobacterial compounds must be involved in the inhibitory activities. The final results indicated these three extracts (from Malaphis chinensis, Cynips gallae-tinctoriae and Fructus mume) had the potential to be developed as algicides due to their remarkably anticyanobacterial activities

Construction of a DNA Chip for Screening of Genetic Hearing Loss

ObjectivesHearing loss is the most common sensory disorder in humans and genetic causes are estimated to cause more than 50% of all incidents of congenital hearing loss. To develop an efficient method for a genetic diagnosis of hearing loss, we have developed and validated a genetic hearing loss DNA chip that allows the simultaneous analysis of 7 different mutations in the GJB2, SLC26A4, and the mtDNA 12S rRNA genes in Koreans.MethodsA genotyping microarray, based on the allele-specific primer extension (ASPE) method, was used and preliminary validation was examined from the five patients and five controls that were already known their genotypes by DNA sequencing analysis.ResultsThe cutoff Genotyping index (GI) of genotyping for each mutation was set up and validated to discriminate among the genotypes. The result of the DNA chip assay was identical to those of previous results.ConclusionWe successfully designed the genetic hearing loss DNA chip for the first time in Korea and it would be useful for a clinical genetic diagnosis of hearing loss. Further consideration will be needed in order to examine the accuracy of this DNA chip with much larger patient sample numbers

Expression of Pro-inflammatory Protein S100A12 (EN-RAGE) in Behçet's Disease and Its Association with Disease Activity: A Pilot Study

BACKGROUND: S100A12 is a member of the S100 family of calcium-binding proteins and is secreted either in inflamed tissues or in the bloodstream by activated neutrophils. Expression of S100A12 has been reported in various diseases, especially non-infectious inflammatory diseases, such as Kawasaki disease, giant cell arteritis and inflammatory bowel disease. OBJECTIVE: This study was conducted to determine both the tissue expression and the serum levels of S100A12 in Behçet's disease (BD) patients and the correlation of the S100A12 serum level with disease activity of BD. METHODS: We included in this study ten BD patients who fulfilled the criteria for diagnosis, according to the International Study Group for BD. The activity of BD was calculated using the BD Current Activity Form. The serum concentrations of both S100A12 and interleukin-8 were measured by the enzyme-linked immunosorbent assay, before and after treatment. Immunohistochemical studies were also performed to detect S100A12 expression in the skin. RESULTS: The serum S100A12 level was significantly increased in the active BD period (p<0.001), in the inactive BD period (p=0.041) and in patients with active Kawasaki disease (p=0.028), compared with the serum level in the healthy controls. The serum S100A12 level decreased significantly from baseline, compared to post-treatment (p=0.017). The activity score of BD was significantly correlated with the serum level of S100A12 (Spearman's coefficient=0.464, p=0.039). Immunohistochemical studies showed that S100A12 was strongly expressed in the erythema nodosum-like skin lesions of patients. CONCLUSION: S100A12 contributes to the pathogenesis of BD related to neutrophil hyperactivity and reflects the disease activity in BD patientsope

Abnormal Integrity of Corticocortical Tracts in Mild Cognitive Impairment: A Diffusion Tensor Imaging Study

Mild cognitive impairment (MCI) has been defined as a transitional state between normal aging and Alzheimer disease. Diffusion tensor imaging (DTI) can estimate the microstructural integrity of white matter tracts in MCI. We evaluated the microstructural changes in the white matter of MCI patients with DTI. We recruited 11 patients with MCI who met the working criteria of MCI and 11 elderly normal controls. The mean diffusivity (MD) and fractional anisotropy (FA) were measured in 26 regions of the brain with the regions of interest (ROIs) method. In the MCI patients, FA values were significantly decreased in the hippocampus, the posterior limb of the internal capsule, the splenium of corpus callosum, and in the superior and inferior longitudinal fasciculus compared to the control group. MD values were significantly increased in the hippocampus, the anterior and posterior limbs of the internal capsules, the splenium of the corpus callosum, the right frontal lobe, and in the superior and the inferior longitudinal fasciculus. Microstructural changes of several corticocortical tracts associated with cognition were identified in patients with MCI. FA and MD values of DTI may be used as novel biomarkers for the evaluation of neurodegenerative disorders

Ischemic and Bleeding Events Associated with Thrombocytopenia and Thrombocytosis after Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction

The early and late ischemic and bleeding clinical outcomes according to baseline platelet count after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) remain unclear. Overall, 10,667 patients from the Cardiovascular Risk and identification of potential high-risk population in AMI (COREA-AMI) I and II registries were classified according to the following universal criteria on baseline platelet counts: (1) moderate to severe thrombocytopenia (platelet \u3c 100 K/µL, n = 101), (2) mild thrombocytopenia (platelet = 100~149 K/µL, n = 631), (3) normal reference (platelet = 150~450 K/µL, n = 9832), and (4) thrombocytosis (platelet \u3e 450 K/µL, n = 103). The primary endpoint was the occurrence of major adverse cardiovascular events (MACE). The secondary outcome was Bleeding Academic Research Consortium (BARC) 2, 3, and 5 bleeding. After adjusting for confounders, the moderate to severe thrombocytopenia (HR, 2.03; 95% CI, 1.49–2.78); p \u3c 0.001), mild thrombocytopenia (HR, 1.15; 95% CI, 1.01–1.34; p = 0.045), and thrombocytosis groups (HR, 1.47; 95% CI, 1.07–2.03; p = 0.019) showed higher 5-year MACE rates than the normal reference. In BARC 2, 3, and 5 bleeding outcomes, the bleedings rates were higher than the normal range in the moderate to severe thrombocytopenia (HR, 2.18; 95% CI, 1.36–3.49; p = 0.001) and mild thrombocytopenia (HR, 1.41; 95% CI, 1.12–1.78; p = 0.004) groups. Patients with AMI had higher 5-year MACE rates after PCI if they had lower- or higher-than-normal platelet counts. Thrombocytopenia revealed higher early and late bleeding rates whereas thrombocytosis showed long-term bleeding trends, although these trends were not statistically significant

Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)

PurposePrevious studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort.MethodsThe levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia.ResultsThe median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ≥75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend=0.0004).ConclusionThe results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants

Pre-Engraftment Syndrome after Unrelated Cord Blood Transplantation: A Predictor of Engraftment and Acute Graft-versus-Host Disease

AbstractPre-engraftment syndrome (PES) is poorly characterized, and its clinical significance and the prognostic impact after unrelated cord blood transplantation (CBT) are unclear. To address these issues, we retrospectively analyzed the incidence, risk factors, and clinical outcomes of PES in unrelated CBT recipients. Data of 381 patients who received unrelated CBT from 18 medical centers in Korea were reviewed. PES was defined as unexplained fever >38.3°C not associated with infection, and/or unexplained skin rash with or without evidence of fluid retention before neutrophil recovery. PES developed in 102 patients (26.8%) at a median of 7 days after CBT. Of these patients, 74 patients (72.5%) received intravenous corticosteroid at a median dose of 1 mg/kg/day, and of these, 95% showed clinical improvement. Risk factors for developing PES included low risk disease, myeloablative conditioning, graft-versus-host disease (GVHD) prophylaxis without methotrexate or corticosteroid, and >5.43 x 107/kg infused nucleated cells. Absence of PES was one of the risk factors for graft failure in multivariate analysis. The cumulative incidence of grade II to grade IV acute GVHD by 100 days after CBT was higher in patients with PES than in those without PES (56.0% versus 34.4%, P < .01). PES was not associated with chronic GVHD, treatment-related mortality, relapse, or overall survival. PES seems to be common after CBT and may be associated with enhanced engraftment without significant morbidity