32 resultados para Volatilità implicita, formula di Black and Scholes


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Intrasexual selection on body coloration is thought to play an important role in the evolution of colour polymorphism, but its physiological underpinnings have received limited attention. In the colour polymorphic cichlid Neochromis omnicaeruleus, three fully sympatric female colour morphs— a plain morph (P) and two conspicuously coloured blotched morphs, black-and-white blotched (WB) and orange blotched (OB)—differ in agonistic behaviour. We compared routine metabolic rate (when females were housed in social isolation), short-term energetic costs of interacting with a same-colour rival housed in an adjacent transparent chamber and oxidative stress between the three female colour morphs. WB females had a lower routine metabolic rate compared with the other colour morphs. WB females also had a lower active metabolic rate during inter-female interactions than OB females, while OB females used more oxygen per unit aggressive act than the other two colour morphs. However, there were no consistent differences in oxidative stress between the three morphs. Concerted divergence in colour, behaviour and metabolism might contribute to the evolution of these polymorphisms in sympatry.

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BACKGROUND Low levels of testosterone in men and changes in retinal microvascular calibre are both associated with hypertension and cardiovascular disease risk. Sex hormones are also associated with blood flow in microvascular beds which might be a key intermediate mechanism in the development of hypertension. Whether a direct association between endogenous testosterone and retinal microvascular calibre exists is currently unknown. We aimed to determine whether testosterone is independently associated with ocular perfusion via a possible association with retinal vascular calibre or whether it plays only a secondary role via its effect on blood pressure in a bi-ethnic male cohort. PROBANDS AND METHODS A total of 72 black and 81 white men (28-68 years of age) from the follow-up phase of the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study were included in this sub-study. Ambulatory pulse pressure and intraocular perfusion pressures were obtained, while metabolic variables and testosterone were measured from fasting venous blood samples. Retinal vascular calibre was quantified from digital photographs using standardised protocols. RESULTS The black men revealed a poorer cardiometabolic profile and higher pulsatile pressure (>50 mm Hg), intraocular pressure and diastolic ocular perfusion pressure than the white men (p≤0.05). Only in the white men was free testosterone positively associated with retinal calibre, i.e. arterio-venular ratio and central retinal arterial calibre and inversely with central retinal venular calibre. These associations were not found in the black men, independent of whether pulse pressure and ocular perfusion pressure were part of the model. CONCLUSIONS These results suggest an independent, protective effect of testosterone on the retinal vasculature where an apparent vasodilatory response in the retinal resistance microvessels was observed in white men.

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UNLABELLED Obesity is a well-recognized risk factor for atrial fibrillation (AF), yet adiposity measures other than body mass index (BMI) have had limited assessment in relation to AF risk. We examined the associations of adiposity measures with AF in a biracial cohort of older adults. Given established racial differences in obesity and AF, we assessed for differences by black and white race in relating adiposity and AF. METHODS We analyzed data from 2,717 participants of the Health, Aging, and Body Composition Study. Adiposity measures were BMI, abdominal circumference, subcutaneous and visceral fat area, and total and percent fat mass. We determined the associations between the adiposity measures and 10-year incidence of AF using Cox proportional hazards models and assessed for their racial differences in these estimates. RESULTS In multivariable-adjusted models, 1-SD increases in BMI, abdominal circumference, and total fat mass were associated with a 13% to 16% increased AF risk (hazard ratio [HR] 1.14, 95% CI 1.02-1.28; HR 1.16, 95% CI 1.04-1.28; and HR 1.13, 95% CI 1.002-1.27). Subcutaneous and visceral fat areas were not significantly associated with incident AF. We did not identify racial differences in the associations between the adiposity measures and AF. CONCLUSION Body mass index, abdominal circumference, and total fat mass are associated with risk of AF for 10years among white and black older adults. Obesity is one of a limited number of modifiable risk factors for AF; future studies are essential to evaluate how obesity reduction can modify the incidence of AF.

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BACKGROUND Racial disparities in kidney transplantation in children have been found in the United States, but have not been studied before in Europe. STUDY DESIGN Cohort study. SETTING & PARTICIPANTS Data were derived from the ESPN/ERA-EDTA Registry, an international pediatric renal registry collecting data from 36 European countries. This analysis included 1,134 young patients (aged ≤19 years) from 8 medium- to high-income countries who initiated renal replacement therapy (RRT) in 2006 to 2012. FACTOR Racial background. OUTCOMES & MEASUREMENTS Differences between racial groups in access to kidney transplantation, transplant survival, and overall survival on RRT were examined using Cox regression analysis while adjusting for age at RRT initiation, sex, and country of residence. RESULTS 868 (76.5%) patients were white; 59 (5.2%), black; 116 (10.2%), Asian; and 91 (8.0%), from other racial groups. After a median follow-up of 2.8 (range, 0.1-3.0) years, we found that black (HR, 0.49; 95% CI, 0.34-0.72) and Asian (HR, 0.54; 95% CI, 0.41-0.71) patients were less likely to receive a kidney transplant than white patients. These disparities persisted after adjustment for primary renal disease. Transplant survival rates were similar across racial groups. Asian patients had higher overall mortality risk on RRT compared with white patients (HR, 2.50; 95% CI, 1.14-5.49). Adjustment for primary kidney disease reduced the effect of Asian background, suggesting that part of the association may be explained by differences in the underlying kidney disease between racial groups. LIMITATIONS No data for socioeconomic status, blood group, and HLA profile. CONCLUSIONS We believe this is the first study examining racial differences in access to and outcomes of kidney transplantation in a large European population. We found important differences with less favorable outcomes for black and Asian patients. Further research is required to address the barriers to optimal treatment among racial minority groups.

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A black and white German Holstein calf displayed a complex double malformation in shape of a thoracopagus parasiticus. By means of a molecular genetic investigation the genesis of the malformation from one zygote could be demonstrated. Both vertebral columns showed a pronounced lordosis, with the vertebral column of one animal ending in a rudimentary head. Close to this rudiment two derivates of branchial arches were found. The two thoracic cavities merged into one "thorax". In the shared thoracic cavity one heart was found. In its right atrium, a cherry-sized structure was found in which heart- and vascular smooth muscles were demonstrated histologically. The aorta split shortly after its origin to provide both animals with one aorta each. The larger pair of lungs was connected with a trachea leading to the head while the smaller pair of lungs originated from a trachea deriving from the rudimentary head. The diaphragm jejunum and split afterwards. The pedigree of the affected animal showed neither inbreeding nor any other affected animal.

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Congenital syndactyly with a variable number of affected feet was observed in eight black and white German Holstein calves. Analysis of the pedigree data revealed that all affected individuals could be traced back to a single founder. The pedigree was consistent with monogenic autosomal recessive inheritance and variable expressivity. Bovine syndactyly or "mulefoot" has been previously shown to map on the telomeric end of bovine chromosome 15 and we performed PCR genotyping of microsatellite markers spanning 27 cM of this chromosomal region to test the new cases for genetic linkage with the phenotype. The haplotype segregation confirmed the suggested inheritance pattern of the mulefoot mutation in this family and markers RM004, BM848 and BMS820 showed significant linkage to the phenotype. The results confirmed the chromosomal location of the mulefoot gene in this pedigree. Furthermore the study demonstrated that although marker testing has been available for nearly a decade the use of mulefoot carriers in cattle breeding remains uncontrolled. The presented family provides a resource for positional cloning of the causative mutation.

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PURPOSE: To compare adjuvant dose-intensive epirubicin and cyclophosphamide chemotherapy administered with filgrastim and progenitor cell support (DI-EC) with standard-dose anthracycline-based chemotherapy (SD-CT) for patients with early-stage breast cancer and a high risk of relapse, defined as stage II disease with 10 or more positive axillary nodes; or an estrogen receptor-negative or stage III tumor with five or more positive axillary nodes. PATIENTS AND METHODS: Three hundred forty-four patients were randomized after surgery to receive seven cycles of SD-CT over 22 weeks, or three cycles of DI-EC (epirubicin 200 mg/m2 plus cyclophosphamide 4 gm/m2 with filgrastim and progenitor cell support) over 6 weeks. All patients were assigned tamoxifen at the completion of chemotherapy. The primary end point was disease-free survival (DFS). RESULTS: After a median follow-up of 5.8 years (range, 3 to 8.4 years), 188 DFS events had occurred (DI-EC, 86 events; SD-CT, 102 events). The 5-year DFS was 52% for DI-EC and 43% for SD-CT, with hazard ratio of DI-EC compared with SD-CT of 0.77 (95% CI, 0.58 to 1.02; P = .07). The 5-year overall survival was 70% for DI-EC and 61% for SD-CT, with a hazard ratio of 0.79 (95% CI, 0.56 to 1.11; P = .17). There were eight cases (5%) of anthracycline-induced cardiomyopathy (two fatal) among those who received DI-EC. Women with hormone receptor-positive tumors benefited significantly from DI-EC. CONCLUSION: There was a trend in favor of DI-EC with respect to disease-free survival. A larger trial or meta-analysis will be required to reveal the true effect of dose-intensive therapy.

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Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces that maintain heritable phenotypic variation in nature. Male color morphs often differ in behavioral dominance, affecting the evolution of color polymorphisms. However, behavioral dominance among female color morphs has received far less attention. We studied a polymorphic population of the cichlid fish Neochromis omnicaeruleus from Lake Victoria, in which 3 distinct female color morphs coexist, black-and-white blotched (WB), orange blotched (OB), and plain (P) color morphs. First, we investigated dominance relationships among female morphs using triadic and dyadic encounters in the laboratory. In triadic encounters, both WB and OB females dominated plain, whereas WB females dominated OB females. Dominance of WB over OB was confirmed using dyadic encounters. In a second experiment, blotched (WB or OB) and plain full-sib sisters were bred by crossing a blotched and a plain parent. In dyadic encounters, WB female morphs dominated their plain sisters, suggesting that dominance of WB females is a pleiotropic effect of color or that genes coding for color and those influencing behavioral dominance are genetically linked, explaining the association between color and behavioral dominance despite gene flow. We conclude that behavioral dominance asymmetries exist among female color morphs of the fish N. omnicaeruleus, and discuss possible mechanisms that may account for the tight association between color and behavioral dominance.

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Most published genomewide association studies (GWAS) in sheep have investigated recessively inherited monogenic traits. The objective here was to assess the feasibility of performing GWAS for a dominant trait for which the genetic basis was already known. A total of 42 Manchega and Rasa Aragonesa sheep that segregate solid black or white coat pigmentation were genotyped using the SNP50 BeadChip. Previous analysis in Manchegas demonstrated a complete association between the pigmentation trait and alleles of the MC1R gene, setting an a priori expectation for GWAS. Multiple methods were used to identify and quantify the strength of population substructure between black and white animals, before allelic association testing was performed for 49 034 SNPs. Following correction for substructure, GWAS identified the most strongly associated SNP (s26449) was also the closest to the MC1R gene. The finding was strongly supported by the permutation tree-based random forest (RF) analysis. Importantly, GWAS identified unlinked SNP with only slightly lower p-values than for s26449. Random forest analysis indicated these were false positives, suggesting interpretation based on both approaches was beneficial. The results indicate that a combined analytical approach can be successful in studies where a modest number of animals are available and substantial population stratification exists.

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The recent development of a goat SNP genotyping microarray enables genome-wide association studies in this important livestock species. We investigated the genetic basis of the black and brown coat colour in Valais Blacknecked and Coppernecked goats. A genome-wide association analysis using goat SNP50 BeadChip genotypes of 22 cases and 23 controls allowed us to map the locus for the brown coat colour to goat chromosome 8. The TYRP1 gene is located within the associated chromosomal region, and TYRP1 variants cause similar coat colour phenotypes in different species. We thus considered TYRP1 as a strong positional and functional candidate. We resequenced the caprine TYRP1 gene by Sanger and Illumina sequencing and identified two non-synonymous variants, p.Ile478Thr and p.Gly496Asp, that might have a functional impact on the TYRP1 protein. However, based on the obtained pedigree and genotype data, the brown coat colour in these goats is not due to a single recessive loss-of-function allele. Surprisingly, the genotype distribution and the pedigree data suggest that the (496) Asp allele might possibly act in a dominant manner. The (496) Asp allele was present in 77 of 81 investigated Coppernecked goats and did not occur in black goats. This strongly suggests heterogeneity underlying the brown coat colour in Coppernecked goats. Functional experiments or targeted matings will be required to verify the unexpected preliminary findings.

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AIMS To estimate physical activity trajectories for people who quit smoking, and compare them to what would have been expected had smoking continued. DESIGN, SETTING AND PARTICIPANTS A total of 5115 participants in the Coronary Artery Risk Development in Young Adults Study (CARDIA) study, a population-based study of African American and European American people recruited at age 18-30 years in 1985/6 and followed over 25 years. MEASUREMENTS Physical activity was self-reported during clinical examinations at baseline (1985/6) and at years 2, 5, 7, 10, 15, 20 and 25 (2010/11); smoking status was reported each year (at examinations or by telephone, and imputed where missing). We used mixed linear models to estimate trajectories of physical activity under varying smoking conditions, with adjustment for participant characteristics and secular trends. FINDINGS We found significant interactions by race/sex (P = 0.02 for the interaction with cumulative years of smoking), hence we investigated the subgroups separately. Increasing years of smoking were associated with a decline in physical activity in black and white women and black men [e.g. coefficient for 10 years of smoking: -0.14; 95% confidence interval (CI) = -0.20 to -0.07, P < 0.001 for white women]. An increase in physical activity was associated with years since smoking cessation in white men (coefficient 0.06; 95% CI = 0 to 0.13, P = 0.05). The physical activity trajectory for people who quit diverged progressively towards higher physical activity from the expected trajectory had smoking continued. For example, physical activity was 34% higher (95% CI = 18 to 52%; P < 0.001) for white women 10 years after stopping compared with continuing smoking for those 10 years (P = 0.21 for race/sex differences). CONCLUSIONS Smokers who quit have progressively higher levels of physical activity in the years after quitting compared with continuing smokers.

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The results of Eurosceptic parties in the recent European parliament election provide further evidence that the “permissive consensus” on European integration blurred. This paper focuses on the structure of the debate on EU integration issues. Which EU integration issues and positions do parties put forward? Can the debate on EU integration issues be subsumed in one or several dimensions? Do they reflect national political conflicts such as the left-right and the ‘new politics’/cultural divide? Or do they form one unique or several EU-specific dimensions, e.g. national sovereignty versus integration? In order to address these questions, this paper departs from the assumption that debate on European integration is multidimensional in its nature and therefore entails a multitude of issue areas. In other words, it does not look at how socio-economic and cultural issues are related to European integration but focuses on its components, i.e. particular EU-specific policies such as EU-wide employment, environment, immigration and monetary policy. The paper departs from the cleavage theory on political di-visions and different approaches transferring them to EU politics. Two points should be noted; first, this paper does not compare the debate on European integration issues between the national level and the EU level, but whether domestic divisions are reflected at the EU level. Second, it is not concerned with the general ideo-logical profile of political parties on EU integration issues, but on EU issues that parties communicated through press releases. By doing this, the paper is concerned with the salient EU issues that parties touch upon.

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BACKGROUND Pinschers and other dogs with coat color dilution show a characteristic pigmentation phenotype. The fur colors are a lighter shade, e.g. silvery grey (blue) instead of black and a sandy color (Isabella fawn) instead of red or brown. In some dogs the coat color dilution is sometimes accompanied by hair loss and recurrent skin inflammation, the so called color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD). In humans and mice a comparable pigmentation phenotype without any documented hair loss is caused by mutations within the melanophilin gene (MLPH). RESULTS We sequenced the canine MLPH gene and performed a mutation analysis of the MLPH exons in 6 Doberman Pinschers and 5 German Pinschers. A total of 48 sequence variations was identified within and between the breeds. Three families of dogs showed co-segregation for at least one polymorphism in an MLPH exon and the dilute phenotype. No single polymorphism was identified in the coding sequences or at splice sites that is likely to be causative for the dilute phenotype of all dogs examined. In 18 German Pinschers a mutation in exon 7 (R199H) was consistently associated with the dilute phenotype. However, as this mutation was present in homozygous state in four dogs of other breeds with wildtype pigmentation, it seems unlikely that this mutation is truly causative for coat color dilution. In Doberman Pinschers as well as in Large Munsterlanders with BHFD, a set of single nucleotide polymorphisms (SNPs) around exon 2 was identified that show a highly significant association to the dilute phenotype. CONCLUSION This study provides evidence that coat color dilution is caused by one or more mutations within or near the MLPH gene in several dog breeds. The data on polymorphisms that are strongly associated with the dilute phenotype will allow the genetic testing of Pinschers to facilitate the breeding of dogs with defined coat colors and to select against Large Munsterlanders carrying BHFD.