Моделирование изменения цен финансовых активов

В работе представлена модель процесса изменения цен финансовых активов на рынке. Описан путь построения модели, ее экономическая интерпретация, найдены моменты процесса и исследовано его поведение в предельном случае. Для сравнения с данной моделью приведены примеры некоторых других существующих моделей.У рoботi представлена модель процесу змiни цiн фiнансових активiв на ринку. Описано шлях побудови моделi, її економiчна iнтерпретацiя, знайдено моменти процесу, дослiджено його поведiнку у граничному випадку. Для порiвняння з даною моделлю наведено приклади деяких iнших моделей, що iснують.A model of process for financial assets — prices changing on market is presented. The way of the model’s construction is described, its economic interpretation, a moments of the process are obtained, its behavior in limit case is investigated. For comparison with the given model examples of other models are presented

Immunization of young heifers with staphylococcal immune evasion proteins before natural exposure to Staphylococcus aureus induces a humoral immune response in serum and milk

Background: Staphylococcus aureus, a leading cause of mastitis in dairy cattle, causes severe mastitis and/or chronic persistent infections with detrimental effects on the cows' wellbeing, lifespan and milk production. Despite years of research there is no effective vaccine against S. aureus mastitis. Boosting of non-protective pre-existing immunity to S. aureus, induced by natural exposure to S. aureus, by vaccination may interfere with vaccine efficacy. The aim was to assess whether experimental immunization of S. aureus naïve animals results in an immune response that differs from immunity following natural exposure to S. aureus. Results: First, to define the period during which calves are immunologically naïve for S. aureus, Efb, LukM, and whole-cell S. aureus specific serum antibodies were measured in a cohort of newborn calves by ELISA. Rising S. aureus specific antibodies indicated that from week 12 onward calves mounted an immune response to S. aureus due to natural exposure. Next, an experimental immunization trial was set up using 8-week-old heifer calves (n = 16), half of which were immunized with the immune evasion molecules Efb and LukM. Immunization was repeated after one year and before parturition and humoral and cellular immunity specific for Efb and LukM was determined throughout the study. Post-partum, antibody levels against LukM and EfB were significantly higher in serum, colostrum and milk in the experimentally immunized animals compared to animals naturally exposed to S. aureus. LukM specific IL17a responses were also significantly higher in the immunized cows post-partum. Conclusions: Experimental immunization with staphylococcal immune evasion molecules starting before natural exposure resulted in significantly higher antibody levels against Efb and LukM around parturition in serum as well as the site of infection, i.e. in colostrum and milk, compared to natural exposure to S. aureus. This study showed that it is practically feasible to vaccinate S. aureus naïve cattle and that experimental immunization induced a humoral immune response that differed from that after natural exposure only.</p

Simultaneous Quantification and Differentiation of Streptococcus suis Serotypes 2 and 9 by Quantitative Real-Time PCR, Evaluated in Tonsillar and Nasal Samples of Pigs : Gelijktijdige kwantificering en differentiatie van Streptococcus suis serotypes 2 en 9 met kwantitatieve Real-Time PCR, onderzocht in tonsil en neus monsters van varkens

Invasive Streptococcus suis (S. suis) infections in pigs are often associated with serotypes 2 and 9. Mucosal sites of healthy pigs can be colonized with these serotypes, often multiple serotypes per pig. To unravel the contribution of these serotypes in pathogenesis and epidemiology, simultaneous quantification of serotypes is needed. A quantitative real-time PCR (qPCR) targeting cps2J (serotypes 2 and 1/2) and cps9H (serotype 9) was evaluated with nasal and tonsillar samples from S. suis exposed pigs. qPCR specifically detected serotypes in all pig samples. The serotypes loads in pig samples estimated by qPCR showed, except for serotype 9 in tonsillar samples (correlation coefficient = 0.25), moderate to strong correlation with loads detected by culture (correlation coefficient > 0.65), and also in pigs exposed to both serotypes (correlation coefficient > 0.75). This qPCR is suitable for simultaneous differentiation and quantification of important S. suis serotypes

Simultaneous Quantification and Differentiation of Streptococcus suis Serotypes 2 and 9 by Quantitative Real-time PCR, Evaluated in Tonsillar and Nasal Samples of Pigs

Abstract Invasive Streptococcus suis (S. suis) infections in pigs are often associated with serotypes 2 and 9. Mucosal sites of healthy pigs can be colonized with these serotypes, often multiple serotypes per pig. To unravel the contribution of these serotypes in pathogenesis and epidemiology, simultaneous quantification of serotypes is needed. A quantitative real-time PCR (qPCR) targeting cps2J (serotypes 2 and 1/2) and cps9H (serotype 9) was evaluated with nasal and tonsillar samples from S. suis exposed pigs. qPCR specifically detected serotypes in all pig samples. The serotypes loads in pig samples estimated by qPCR showed, except for serotype 9 in tonsillar samples (correlation coefficient = 0.25), moderate to strong correlation with loads detected by culture (correlation coefficient > 0.65), and also in pigs exposed to both serotypes (correlation coefficient > 0.75). This qPCR is suitable for simultaneous differentiation and quantification of important S. suis serotype

Effect of simultaneous exposure of pigs to Streptococcus suis serotypes 2 and 9 on colonization and transmission of these serotypes, and on mortality

Introduction Streptococcus suis (S. suis) is a major pathogen in pigs worldwide, causing meningitis, septicemia, arthritis, endocarditis, and mortality. S. suis in humans is considered as an emerging life-threatening infection, especially in Asia. Main risk factor for human infection is direct contact with infected pigs or their products.In pigs, various serotypes of S. suis have been identified as cause of clinical infection. Comparable to e.g. Streptococcus pneumoniae in human, the presence of S. suis serotypes in pigs, however, differs between geographical areas, and varies over time. In several European countries, including The Netherlands, there has been a shift in predominant serotype from serotype 2 towards serotype 9 in the last two decades.We hypothesize a relation with one serotype affecting the other in colonization, transmission and invasion. The aim of this study was to evaluate whether simultaneous exposure of pigs to serotypes 2 and 9 affects the colonization and transmission of each serotype, and affects mortality. Methods Thirty-six caesarean-derived/colostrum-deprived piglets were randomly assigned to three groups, and there housed pair-wise. At 6 weeks-of-age one pig per pair was inoculated intranasally with either one (serotype 2 or 9; ‘mono-group’) or two serotypes simultaneously (‘dual-group’). Pigs in the mono-groups received 1x109 CFU serotype 2 or 9, and in the dual-group a mixture of 1x109 CFU serotype 2 and 1x109 CFU serotype 9 (i.e. 2x109 CFU S. suis/pig). The other pig of each pair was contact-exposed. Tonsillar brushing samples were collected from all pigs during three weeks post inoculation. Bacterial loads in the samples were quantified using multiplex real-time PCR. Transmission rates of the serotypes among pigs were estimated using a mathematical SI-model. Results The transmission rates for serotype 9 were 67/day (95%CI: 0-∞) and 4.1/day (95%CI: 1.6-10.6), for the mono- and dual-group, respectively (P=0.99). The transmission rates for serotype 2 were estimated at 29.4/day (95%CI: 0-∞) in the mono-group, and 2.9/day (95%CI: 1.2-6.9) in the dual-group (P=0.99). Bacterial loads did not differ significantly between serotypes (P=0.99). In the dual-group the average serotype 2 load in tonsillar samples from contact pigs was 1.4-1.8 10LogCFU/sample (i.e. 25-40 fold) reduced on days 1 to 4 and 6, in comparison to the mono-group (P<0.01).Simultaneous exposure to the serotypes reduced the mortality hazard 6.3 times (95%CI: 2.0-19.8) compared to exposure to serotype 2 only, and increased it 6.6 times (95%CI: 1.4–30.9) compared to exposure to serotype 9 only. Conclusions Transmission rates for serotype 2 did neither differ significantly between serotypes, nor for a single serotype between the mono- and dual-group. This implies that simultaneous exposure to serotypes 2 and 9 does not affect the relative transmission rates of each serotype.Natural contact exposure to serotypes 2 and 9 simultaneously affects the clinical outcome of an infection of a particular serotype in a population, possibly by affecting the mucosal load. This might have contributed to the observed shift in distribution of clinical isolates in the field from serotype 2 to 9

Metabolic response of porcine colon explants to in vitro infection by Brachyspira hyodysenteriae: a leap into disease pathophysiology

Introduction: Swine dysentery caused by Brachyspira hyodysenteriae is a production limiting disease in pig farming. Currently antimicrobial therapy is the only treatment and control method available. Objective: The aim of this study was to characterize the metabolic response of porcine colon explants to infection by B. hyodysenteriae. Methods: Porcine colon explants exposed to B. hyodysenteriae were analyzed for histopathological, metabolic and pro-inflammatory gene expression changes. Results: Significant epithelial necrosis, increased levels of l-citrulline and IL-1α were observed on explants infected with B. hyodysenteriae. Conclusions: The spirochete induces necrosis in vitro likely through an inflammatory process mediated by IL-1α and NO

Metabolic response of porcine colon explants to in vitro infection by Brachyspira hyodysenteriae : a leap into disease pathophysiology

Introduction: Swine dysentery caused by Brachyspira hyodysenteriae is a production limiting disease in pig farming. Currently antimicrobial therapy is the only treatment and control method available. Objective: The aim of this study was to characterize the metabolic response of porcine colon explants to infection by B. hyodysenteriae. Methods: Porcine colon explants exposed to B. hyodysenteriae were analyzed for histopathological, metabolic and pro-inflammatory gene expression changes. Results: Significant epithelial necrosis, increased levels of l-citrulline and IL-1α were observed on explants infected with B. hyodysenteriae. Conclusions: The spirochete induces necrosis in vitro likely through an inflammatory process mediated by IL-1α and NO

Effect of Simultaneous Exposure of Pigs to Streptococcus suis Serotypes 2 and 9 on Their Colonization and Transmission, and on Mortality

The distribution of Streptococcus suis serotypes isolated from clinically infected pigs differs between geographical areas, and varies over time. In several European countries, predomination of serotype 2 has changed to serotype 9. We hypothesize a relation, with one serotype affecting the other in colonization and invasion. The aim of this study was to evaluate whether simultaneous exposure of pigs to serotypes 2 and 9 affects colonization and transmission of each type, and mortality. Thirty-six caesarean-derived/colostrum-deprived piglets were randomly assigned to three groups, and there housed pair-wise. At six weeks old, one pig per pair was inoculated with either one (serotype 2 or 9; mono-group) or two serotypes simultaneously (dual-group); the other pig was contact-exposed. Tonsillar and nasal samples were collected within three weeks post inoculation. Bacterial loads in samples were quantified using multiplex real-time polymerase chain reaction (PCR). Transmission rates of the serotypes among pigs were estimated using a mathematical Susceptible-Infectious (SI) model. Bacterial loads and transmission rates did not differ significantly between serotypes. Compared to the mono-group, in the dual-group the average serotype 2 load in tonsillar samples from contact pigs was reduced on days 1 to 4 and on day 6. Simultaneous exposure to the serotypes reduced the mortality hazard 6.3 times (95% C.I.: 2.0-19.8) compared to exposure to serotype 2 only, and increased it 6.6 times (95% C.I.: 1.4-30.9) compared to exposure to serotype 9 only. This study indicates that serotype 2 load and mortality were affected in pigs exposed to these two serotypes

Effect of Simultaneous Exposure of Pigs to Streptococcus suis Serotypes 2 and 9 on Their Colonization and Transmission, and on Mortality

The distribution of Streptococcus suis serotypes isolated from clinically infected pigs differs between geographical areas, and varies over time. In several European countries, predomination of serotype 2 has changed to serotype 9. We hypothesize a relation, with one serotype affecting the other in colonization and invasion. The aim of this study was to evaluate whether simultaneous exposure of pigs to serotypes 2 and 9 affects colonization and transmission of each type, and mortality. Thirty-six caesarean-derived/colostrum-deprived piglets were randomly assigned to three groups, and there housed pair-wise. At six weeks old, one pig per pair was inoculated with either one (serotype 2 or 9; mono-group) or two serotypes simultaneously (dual-group); the other pig was contact-exposed. Tonsillar and nasal samples were collected within three weeks post inoculation. Bacterial loads in samples were quantified using multiplex real-time polymerase chain reaction (PCR). Transmission rates of the serotypes among pigs were estimated using a mathematical Susceptible-Infectious (SI) model. Bacterial loads and transmission rates did not differ significantly between serotypes. Compared to the mono-group, in the dual-group the average serotype 2 load in tonsillar samples from contact pigs was reduced on days 1 to 4 and on day 6. Simultaneous exposure to the serotypes reduced the mortality hazard 6.3 times (95% C.I.: 2.0-19.8) compared to exposure to serotype 2 only, and increased it 6.6 times (95% C.I.: 1.4-30.9) compared to exposure to serotype 9 only. This study indicates that serotype 2 load and mortality were affected in pigs exposed to these two serotypes