A note on arbitrage under transaction costs

Guasoni (2006) introduced a simple condition for the absence of arbitrage opportunities. In this note we show that his results remain valid under a weaker notion of arbitrage which arises by excluding liquidation costs from the value process of a portfolio

Immunity in barren and enriched housed pigs differing in baseline cortisol concentration

It was shown recently that barren housed pigs (small pens, no substrate) have a blunted circadian rhythm of salivary cortisol as compared to enriched housed pigs (large pens with daily fresh bedding). In the light period, enriched housed pigs showed significantly higher concentrations of cortisol in saliva than barren housed pigs, whereas in the dark period, cortisol concentrations were low in both enriched and barren housed pigs. In the present study, the immunological consequences of the difference in baseline salivary cortisol concentration in the light period were evaluated. It appeared that leukocyte and lymphocyte distributions, and in vitro lymphocyte proliferation following ConcanavalineA (ConA) stimulation in the assay using purified lymphocytes were not affected. However, barren and enriched housed pigs did show a different proliferation response to ConA in the whole blood assay. At day 2 of culture, proliferation was higher in barren housed pigs than in enriched housed pigs, whereas at day 4 of culture, proliferation was higher in enriched housed pigs than in barren housed pigs. Lymphocyte proliferation at day 2 of culture in the whole blood assay correlated negatively with plasma cortisol levels, which might thus explain the higher proliferation in barren housed pigs at day 2 of culture. The in vivo humoral and cellular (delayed type hypersensitivity, DTH) immune response to KLH was not affected by housing conditions. We conclude that, although baseline salivary cortisol concentrations differ between enriched and barren housed pigs, immune function appears to be relatively unaffected.

Establishment of pluripotent cell lines from vertebrate species - Present status and future prospects

Pluripotent embryonic stem (ES) cells are undifferentiated cell lines derived from early embryos and are capable of unlimited undifferentiated proliferation in vitro. They retain the ability to differentiate into all cell types including germ cells in chimeric animals in vivo, and can be induced to form derivatives of all three germ layers in vitro. Mouse ES cells represent one of the most important tools in genetic research. Major applications include the targeted mutation of specific genes by homologous recombination and the discovery of new genes by gene trap strategies. These applications would be of high interest for other model organisms and also for livestock species, However, in spite of tremendous research activities, no proven ES cells colonizing the germ line have been established for vertebrate species other than mouse a nd chicken thus far. This review summarizes the current status of deriving pluripotent embryonic stem cell lines from vertebrates and recent developments in nuclear transfer technology, which may provide an alternative tool for genetic modification of livestock animals. Copyright (C) 1999 S. Karger AG, Basel

Effects of environmental enrichment on behavioral responses to novelty, learning, and memory, and the circadian rhythm in cortisol in growing pigs

Previously we showed that pigs reared in an enriched environment had higher baseline salivary cortisol concentrations during the light period than pigs reared under barren conditions. In the present experiment, it was investigated whether these higher baseline salivary cortisol concentrations were a real difference in cortisol concentration or merely represented a phase difference in circadian rhythm. The effects of different cortisol concentrations on the behavioral responses to novelty and learning and long-term memory in a maze test were also studied in enriched and barren housed pigs. At 9 weeks of age enriched and barren housed pigs did not differ in baseline salivary cortisol concentrations nor in circadian rhythm, but at 22 weeks of age barren housed pigs had a blunted circadian rhythm in salivary cortisol as compared to enriched housed pigs. The differences in baseline salivary cortisol concentrations between enriched- and barren-housed pigs are age-dependent, and become visible after 15 weeks of age. Enriched- and barren-housed piglets did not differ in time spent on exploration in the novel environment test. Barren-housed pigs had an impaired long-term memory in the maze test compared to enriched-housed pigs; however, no differences in learning abilities between enriched- and barren-housed pigs were found. Because blunted circadian cortisol rhythms are often recorded during states of chronic stress in pigs and rats or during depression in humans, it is suggested that the blunted circadian rhythm in cortisol in barren-housed pigs similarily may reflect decreased welfare.

A Method to Tackle First Order Differential Equations with Liouvillian Functions in the Solution - II

We present a semi-decision procedure to tackle first order differential equations, with Liouvillian functions in the solution (LFOODEs). As in the case of the Prelle-Singer procedure, this method is based on the knowledge of the integrating factor structure.Comment: 11 pages, late

A Mycoplasma hyopneumoniae One- Shot vaccine in comparison to a conventional Two- Shot vaccine in a commercial farrow- to- finish pig herd with low health status

Deckblatt-Impressum Inhaltsverzeichnis Abkürzungsverzeichnis Einleitung Literaturübersicht Material und Methoden Ergebnisse Diskussion Schlussfolgerungen Zusammenfassung Summary Literaturverzeichnis Danksagung SelbständigkeitserklärungDas Ziel dieser Studie war, den Einfluss verschiedener Impfprogramme gegen M. hyo auf klinische Parameter, Wachstums- und Schlachtleistung, die Lungengesundheit und Immunitätsentwicklung beim Schwein zu erfassen. Der Vergleich wurde zwischen 3 Gruppen gestellt. Die erste Gruppe wurde mit einem Zweifachimpfstoff am 7. und 28. Lebenstag geimpft, die zweite Gruppe mit einem Einfachimpfstoff am 7. Lebenstag. Die dritte Gruppe wurde mit 0,9%iger Kochsalzlösung, einem Placebo, behandelt und stellte die Kontrollgruppe dar. Der Untersuchungszeitraum lag zwischen August 2004 und März 2005. In dieser Zeit wurden die Tiere in Bezug auf klinische Symptomatik beobachtet und wenn erforderlich behandelt. Einer Stichprobe von Tieren wurde mehrfach Blut entnommen, um dieses immunologisch zu untersuchen. Bei der Schlachtung wurden die Lungen mit einem Lungenscore- System beurteilt und stichprobenartig bakteriologisch untersucht. Gewichte wurden bei der Geburt, beim Absetzen, bei Einstallung in die Mast und auf dem Schlachthof ermittelt. Der Magerfleischanteil wurde am Schlachthof bestimmt. 1\. Klinisch- ökonomische Ergebnisse \- Die einfach geimpften Tiere schnitten während der Läuferphase in Bezug auf die Wachstumsleistung deutlich besser ab als die konventionell zweifach geimpften Tiere und die Kontrollgruppe. Vor allem die Tiere mit schlechtem Gesundheitsstatus konnten von der Impfung profitieren. \- In der Endmast kam es signifikant häufiger in der einmalig vakzinierten Gruppe zu Husten als in der zweimalig geimpften Gruppe und in der Kontrollgruppe. Husten generell konnte mit der Buchtenposition assoziiert werden und hatte bei einer großen Zahl der geschlachteten Tiere einen signifikanten negativen Einfluss auf die Lungengesundheit und das Schlachtgewicht. \- Bei der Schlachtung ergaben sich jedoch weder durch die Einfachvakzine noch durch die konventionelle Zweifachimpfung wirtschaftliche Erfolge. 2\. Immunologische Ergebnisse \- Die Einfachimpfung hat in dieser Studie nicht zu einer Steigerung der Produktion von Antikörpern gegen M. hyo geführt, während die konventionelle Impfung 4 Wochen nach der Boosterung den Antikörpertiter- Spiegel in einigen Tieren ansteigen ließ. Dieser Anstieg zeigte keine Assoziationen mit den klinisch- wirtschaftlichen Parametern. \- Die Infektion mit M. hyo erfolgte wahrscheinlich in den 3 bis 7 Wochen vor dem Schlachttermin. \- Der hohe Antikörpertiter am Ende der Mast war negativ mit dem Schlachtgewicht und der Lungengesundheit assoziiert. \- Der Anteil an B- Zellen ist in der 8. und 12. Lebenswoche in allen Gruppen sehr niedrig. \- Die geimpften Tiere beider Gruppen zeigen einen von der Kontrollgruppe abweichenden Verlauf der CD4+/CD8+ T- Zellratio, unterscheiden sich untereinander aber nicht. Bedingt wird die Abweichung der Kontrollgruppe sowohl durch einen niedrigeren Anteil an CD8+ T-Zellen als auch durch einen höheren Anteil an CD4+ T- Zellen in der 12. und 25. Lebenswoche. Auch hier zeigen sich keine Assoziationen mit den klinisch- wirtschaftlichen Parametern. In dieser Studie zeigte die Einfachimpfung anfänglich Verbesserungen der wirtschaftlichen Leistungen, konnte aber nicht zu einer Langzeitwirkung führen, möglicherweise stand dies in Zusammenhang mit einer Immunsuppression vor Beginn der Mast. Aber auch die konventionelle Impfung erbrachte, im Vergleich zu der nicht geimpften Kontrollgruppe, in diesem Bestand keine Erfolge. Die Möglichkeiten des Impfversagens durch multifaktorielle Einflüsse in diesem Bestand wurden diskutiert. Immunologisch gesehen fehlte beiden Impfregimen eine Serokonversion nach der Impfung. Die hohen Titer gegen Mastende sprechen eher für eine akute Feldinfektion ca. 3- 7 Wochen vor der Schlachtung. Ein geringer Effekt beider Impfungen auf die Zellzusammensetzung konnte zum Zeitpunkt der Infektion mit M. hyo festgestellt werden.The goal of this study was to gather information about the influence of different vaccination schedules on clinics, growth- and slaughter achievements, lung score, and development of immunity in pigs. 3 groups were compared. The first group was vaccinated with a Two- Shot vaccine on day 7 and 28 after birth, the second group was vaccinated with a One- Shot vaccine on day 7 after birth. The third group received 0,9% NaCl as a placebo and served as a control. The study took place between August 2004 and March 2005. In this time period animals were surveyed and if necessary medically treated. Blood was taken regularily from a sample of animals for immunological research. At slaughter the lungs were evaluated with a lung score system and samples were taken for microbiological examination. Weights were taken at birth, after weaning, when moving to the fattening stable and after slaughter. The proportion of lean meat was determined at slaughter. 1\. Clinical and economical results \- The One- Shot vaccine gained better results than the Two- Shot vaccine and the placebo concerning weight gain in the farrowing period. Especially animals with a questionable health status could take profit out of the One- Shot vaccine. \- In the fattening period the animals vaccinated once were coughing more frequently than the animals vaccinated twice or the controls. Coughing at the end of the fattening period could be associated with position of the farrowing pen in the stable implicating the influence of climatic conditions and bad health of the lungs and low weight at slaughter. \- At slaughter neither the One- Shot- nor the Two- Shot vaccine had delivered an economical advantage. 2\. Immunological results \- In the present study the One- Shot vaccine did not lead to an increased production of antibodies against M. hyo, whilst the conventional vaccination increased the antibody- titer 4 weeks after booster in some of the animals. This rise in antibodies did not show any correlation with clinical- economical parameters. \- A field infection with M. hyo probably occurred around 3 to 7 weeks before slaughter. \- The high titer at the end of the fattening period was negatively associated with lung health and carcass weight \- The proportion of B- cells was low at 8 and 12 weeks of age in all groups \- The vaccinated animals showed a course of CD4+/CD8+ T-cell-ratio different from the control group, there was no variation between the two vaccinated groups. The difference of the control group originated in a lower proportion of CD8+ T- cells as well as a higher proportion of CD4+ T- cells at an age of 12 and 25 weeks. Here as well, there were no correlations with clinical- economical parameters. In this herd the One- Shot vaccine could not lead to economical improvements compared to the Two- Shot vaccine. The Two- Shot vaccine could also not surpass the control. The possible reasons for a vaccine failure in this herd were discussed. The results of the immunological tests show that seroconversion after vaccination is missing. The high antibody- titers at the end of the farrowing period rather support the idea of an acute infection with a M. hyo field strain approximately 3- 7 weeks before slaughter. A small effect on proportions of cell populations could be observed at the time of infection

On the nonexistence of Liouvillian first integrals for generalized Liénard polynomial differential systems

International audienceWe consider generalized Liénard polynomial differential systems. In their work, Llibre and Valls have shown that, except in some particular cases, such systems have no Liouvillian first integral. In this letter, we give a direct and shorter proof of this result

Energy efficient plasma processing of industrial wastes

The paper presents the results of thermodynamic modeling of the process of joint plasma treatment of non-combustible and combustible industrial wastes. The compositions of water-salt-organic compositions based on these wastes and regimes providing their energy-efficient joint treatment in air plasma have been determined

Along the ecocline: physiological responses of Baltic Sea and coastal peatland benthic diatoms to abiotic variables

This dissertation focused on the ecophysiological responses of unialgal diatom isolates from the microphytobenthos in the shallow southern Baltic Sea and adjacent coastal peatlands to the fundamental variables salinity, temperature, and light availability in their respective habitats, as well as the influence of potential mixing of waterbodies of the two ecosystems on growth rates and photosynthetic performance of the benthic diatoms. Results within three publications showed eurythermal and euryhaline growth, a high photo-physiological plasticity and stimulated growth by peatland water