Computing option pricing models under transaction costs

AbstractThis paper deals with the Barles–Soner model arising in the hedging of portfolios for option pricing with transaction costs. This model is based on a correction volatility function Ψ solution of a nonlinear ordinary differential equation. In this paper we obtain relevant properties of the function Ψ which are crucial in the numerical analysis and computing of the underlying nonlinear Black–Scholes equation. Consistency and stability of the proposed numerical method are detailed and illustrative examples are given

MMP-2 and sTNF-R1 variability in patients with essential hypertension: 1-year follow-up study

The aim of this study is to analyze MMP-2 and sTNF-R1 variability, potent predictors of cardiovascular events, in stable hypertensive patients during a 12-month followup. 234 asymptomatic patients (age 6 0 ± 1 3 , 136 male) out of 252 patients with essential hypertension were followed up. MMP-2 and sTNF-R1 were measured at baseline and after 12 months (stage I). To compare MMP-2 and sTNF-R1 levels over time interval, we used the statistical method of Bland-Altman. MMP-2 and sTNF-R1 reproducibility was good in our patients for the two intervals with a coefficient of reproducibility of 8.2% and 11.3%, respectively. The percentages of patients within 1.96 × standard deviation of the mean were 93.6% and 92.7%. An elevated coefficient of correlation was obtained for MMP-2, basal versus stage I

Presión arterial : ¿esfigmomanómetro manual o digital?

El presente es un estudio prospectivo y comparativo entre la medición de la presión arterial obtenida de manera manual con esfigmomanómetro aneroide y la obtenida mediante monitor automático. El desarrollo de la práctica se realizó sobre un grupo de 100 pacientes hospitalizados en el servicio de Neurocirugía y Otorrinolaringología del Consorcio Hospital General de Valencia durante el primer trimestre del año 2007, mediante mediciones secuenciales y efectuadas por el mismo observador con ambos aparatos bien calibrados. Se observó mediante el método de correlación bivariada de Pearson que no existen diferencias estadísticamente significativas entre las presiones tomadas por ambos aparatos determinando así la fiabilidad del aparato automático utilizado en esta sala para el registro de la tensión arterial.This is a prospective and comparative work between arterial pressure obtained through manual measurement with aneroid sphygmomanometer and the arterial pressure obtained through automatic monitor. The practice was carried out in a group of 100 inpatients in the Neurosurgery and Otolaryngology Service in the Consortium of the General Hospital of Valencia during the first term of 2007. The development of this hospital training was made on each individual through sequential measurements and executed by the same observer with both well-calibrated machines. It was observed that through the method of Pearson's bivaried correlation there are not statistically significant differences between the pressures taken by both machines. As regards this fact, both automatic machines of arterial pressure register are [email protected] [email protected]

Role of PEG35, Mitochondrial ALDH2, and Glutathione in Cold Fatty Liver Graft Preservation: An IGL-2 Approach.

The total damage inflicted on the liver before transplantation is associated with severalsurgical manipulations, such as organ recovery, washout of the graft, cold conservation in organpreservation solutions (UW, Celsior, HTK, IGL-1), and rinsing of the organ before implantation.Polyethylene glycol 35 (PEG35) is the oncotic agent present in the IGL-1 solution, which is an alterna-tive to UW and Celsior solutions in liver clinical transplantation. In a model of cold preservation inrats (4◦C; 24 h), we evaluated the effects induced by PEG35 on detoxifying enzymes and nitric oxide,comparing IGL-1 to IGL-0 (which is the same as IGL-1 without PEG). The benefits were also assessedin a new IGL-2 solution characterized by increased concentrations of PEG35 (from 1 g/L to 5 g/L)and glutathione (from 3 mmol/L to 9 mmol/L) compared to IGL-1. We demonstrated that PEG35promoted the mitochondrial enzyme ALDH2, and in combination with glutathione, prevented theformation of toxic aldehyde adducts (measured as 4-hydroxynonenal) and oxidized proteins (AOPP).In addition, PEG35 promoted the vasodilator factor nitric oxide, which may improve the microcircu-latory disturbances in steatotic grafts during preservation and revascularization. All of these resultslead to a reduction in damage inflicted on the fatty liver graft during the cold storage preservation.In this communication, we report on the benefits of IGL-2 in hypothermic static preservation, whichhas already been proved to confer benefits in hypothermic oxygenated dynamic preservation. Hence,the data reported here reinforce the fact that IGL-2 is a suitable alternative to be used as a uniquesolution/perfusate when hypothermic static and preservation strategies are used, either separately orcombined, easing the logistics and avoiding the mixture of different solutions/perfusates, especiallywhen fatty liver grafts are used. Further research regarding new therapeutic and pharmacologicalinsights is needed to explore the underlying mitochondrial mechanisms exerted by PEG35 in staticand dynamic graft preservation strategies for clinical liver transplantation purpos

Role of aldehyde dehydrogenase 2 in ischemia reperfusion injury: An update

Aldehyde dehydrogenase 2 (ALDH2) is best known for its critical detoxifying role in liver alcohol metabolism. However, ALDH2 dysfunction is also involved in a wide range of human pathophysiological situations and is associated with complications such as cardiovascular diseases, diabetes mellitus, neurodegenerative diseases and aging. A growing body of research has shown that ALDH2 provides important protection against oxidative stress and the subsequent loading of toxic aldehydes such as 4-hydroxy-2-nonenal and adducts that occur in human diseases, including ischemia reperfusion injury (IRI). There is increasing evidence of its role in IRI pathophysiology in organs such as heart, brain, small intestine and kidney; however, surprisingly few studies have been carried out in the liver, where ALDH2 is found in abundance. This study reviews the role of ALDH2 in modulating the pathways involved in the pathophysiology of IRI associated with oxidative stress, autophagy and apoptosis. Special emphasis is placed on the role of ALDH2 in different organs, on therapeutic "preconditioning" strategies, and on the use of ALDH2 agonists such as Alda-1, which may become a useful therapeutic tool for preventing the deleterious effects of IRI in organ transplantation

Current status of bacterial spot of stone fruits and almond caused by Xanthomonas arboricola pv. pruni in Spain

In 2002, typical symptoms of bacterial spot disease of stone fruits caused by Xanthomomas arboricola pv. pruni (Xap) were observed for the first time on Japanese plum in Badajoz (south-western Spain). During the following years, the pathogen was found in seven other eastern and northern Spanish provinces (Valencia, Alicante, Zaragoza, Huesca, Navarra, Lérida and Mallorca) affecting different cultivars of Japanese plum, nectarine, peach and almond. There are few previous reports of Xap on almond, the Spanish outbreaks constituting its first detection on this host in the European Union (EU). Identification of the pathogen was performed using biochemical tests, fatty acid methyl esters (FAME) profiles, conventional and real-time PCR, and hypersensitivity reaction on tobacco leaves. Pathogenicity was demonstrated by inoculation of young potted plants of peach, plum or almond and successful re-isolations from plants with symptoms. In areas where infected plants were found, eradication programs were set up since Xap has a quarantine status according to phytosanitary EU legislation.Publishe

Aldehyde Dehydrogenase 2 (ALDH2) in Rat Fatty Liver Cold Ischemia Injury

Institut George Lopez-1 (IGL-1) and Histidine-tryptophan-ketoglutarate (HTK) solutions are proposed as alternatives to UW (gold standard) in liver preservation. Their composition differs in terms of the presence/absence of oncotic agents such as HES or PEG, and is decisive for graft conservation before transplantation. This is especially so when fatty (steatotic) livers are used since these grafts are more vulnerable to ischemia insult during conservation. Their composition determines the extent of the subsequent reperfusion injury after transplantation. Aldehyde dehydrogenase-2 (ALDH2), a mitochondrial enzyme, has been reported to play a protective role in warm ischemia-reperfusion injury (IRI), but its potential in fatty liver cold ischemic injury has not yet been investigated. We evaluated the relevance of ALDH2 activity in cold ischemia injury when fatty liver grafts from Zucker Obese rats were preserved in UW, HTK, and IGL-1 solutions, in order to study the mechanisms involved. ALDH2 upregulation was highest in livers preserved in IGL-1. It was accompanied by a decrease in transaminases, apoptosis (Caspase 3 and TUNEL assay), and lipoperoxidation, which was concomitant with the effective clearance of toxic aldehydes such as 4-hydroxy-nonenal. Variations in ATP levels were also determined. The results were consistent with levels of NF-E2 p45-related factor 2 (Nrf2), an antioxidant factor. Here we report for the first time the relevance of mitochondrial ALDH2 in fatty liver cold preservation and suggest that ALDH2 could be considered a potential therapeutic target or regulator in clinical transplantation

The relevance of the UPS in the fatty liver graft preservation: a new approach for IGL-1 and HTK solutions

The 26S proteasome is the central proteolytic machinery of the ubiquitin proteasome system (UPS), which is involved in the degradation of ubiquitinated protein substrates. Recently, UPS inhibition has been shown to be a key factor in fatty liver graft preservation during organ cold storage using University of Wisconsin solution (UW) and Institute Georges Lopez (IGL-1) solutions. However, the merits of IGL-1 and histidine-tryptophan-ketoglutarate (HTK) solutions for fatty liver preservation have not been compared. Fatty liver grafts from obese Zücker rats were preserved for 24 h at 4 °C. Aspartate aminotransferase and alanine aminotransferase (AST/ALT), glutamate dehydrogenase (GLDH), ATP, adenosine monophosphate protein kinase (AMPK), e-NOS, proteasome activity and liver polyubiquitinated proteins were determined. IGL-1 solution prevented ATP breakdown during cold-storage preservation of steatotic livers to a greater extent than HTK solution. There were concomitant increases in AMPK activation, e-NOS (endothelial NOS (NO synthase)) expression and UPS inhibition. UPS activity is closely related to the composition of the solution used to preserve the organ. IGL-1 solution provided significantly better protection against ischemia-reperfusion for cold-stored fatty liver grafts than HTK solution. The effect is exerted through the activation of the protective AMPK signaling pathway, an increase in e-NOS expression and a dysregulation of the UPS

Comparación de diversos sustratos para su utilización en viveros ecológicos

Se comparan 20 tipos de mezclas de sustratos diferentes, bajo la base de 8 materiales: turba, compost, sustrato forestal, fibra de coco, arena, cascarilla de arroz (en cuatro medidas de triturado), perlita y vermiculita. La mezcla de turba con perlita y vermiculita se tomó como testigo. El ensayo se realiza en bandejas de poliestireno expandido, con dos tipos de especies hortícolas (tomat cult. Rio Grande, y lechuga cult. Inverna). Se miden diversas características: germinación, precocidad, altura de la planta, peso del vuelo y de las raíces, y dificultades durante su cuidado en vivero. Pese a no ser los más precoces, los mejores resultados se obtienen con aquellas mezclas en las cuales se encuentra presente el compost. El mayor desarrollo se adquiere en las de compost con perlita y vermiculita, compost con arroz y compost con fibra de coco. La mezcla de compost con arroz y coco dieron resultados medianos. Las mezclas con arena eran poco manejables, y dieron resultados muy negativos con arroz o coco