Polarizing versus depolarizing blood cardioplegia: An experimental study of myocardial function, metabolism and ultrastructure following cardiopulmonary bypass and cardioplegic arrest

In cardiothoracic surgery, the use of the heart-lung machine for cardiopulmonary bypass (CPB) and induced cardiac arrest, cardioplegia, is required for performing the majority of the surgical procedures. Myocardial protection is essential during the ischemic period of cardioplegia. The aim of this project is to evaluate and verify if a recently developed routine for myocardial protection is feasible, safe and suited for use in clinical practice. This pre-clinical translational animal research project is designed to bridge the gap between basic research and new routines that may benefit the patient. In three different protocols, two groups of animals (10 in each group) are randomized to polarized or depolarized cardioplegic arrest. The novel and unexplored cardioplegic solution with esmolol, adenosine and magnesium; St Thomas’ Hospital polarizing cardioplegia (STH-POL) is compared with today’s gold standard; potassium-based St Thomas’ depolarizing solution (STH-2), both administered as repeated, cold, oxygenated blood. Left ventricular regional and global function in the early hours after weaning from CPB are evaluated together with myocardial ultrastructure and metabolism. Our hypothesis is that STH-POL improves myocardial protection demonstrated as better preserved postoperative cardiac function in a large animal translational model. This knowledge is essential before initiating clinical studies and implementation. An optimal myocardial protection is important when performing cardiac surgery in an ageing population with increased occurrence of more complex heart diseases and comorbidity. Paper I demonstrated improved regional and global contractility following 60 min of cardioplegic arrest with STH-POL compared to STH-2 blood cardioplegia. After weaning from CPB and following reperfusion, left ventricular dP/dtmax, Preload Recruitable Stroke Work and radial peak systolic strain rate were maintained 180 min after declamping in the group with polarized arrest and decreased with depolarized arrest. Paper II focused on energy metabolism and ultrastructure with the STH-POL compared to the STH-2 cardioplegia during 60 min of cardiac arrest and at early reperfusion. The study demonstrated increased levels of creatine phosphate in left ventricular myocardial tissue samples at the end of the period of cardioplegic arrest and early after reperfusion in the STH-POL compared to the STH-2 group. Furthermore, the adenosine triphosphate content was increased and the mitochondrial surface-to-volume ratio decreased with polarizing compared to depolarizing cardioplegia 20 min after reperfusion. However, at 180 min after reperfusion these group differences were negligible. Paper III addressed myocardial function after prolonged cardioplegic arrest for 120 min. A temporary increase in the load-independent contractility variable Preload Recruitable Stroke Work was seen in the STH-POL compared to the STH-2 group 150 min after declamping. Neither regional nor global left ventricular function differed between groups up to 240 min after declamping. However, compared to the STH-2 group, the left ventricular myocardial tissue blood flow rate decreased in the STHPOL group at 150 and 240 min compared to 60 min after declamping. The relationship between the left ventricular total pressure-volume area and blood flow rate was maintained after declamping in the STH-POL group and decreased in the STH-2 group. Thus, cardioplegic arrest with STH-POL alleviated the mismatch between myocardial function and perfusion after weaning from CPB compared to STH-2. Conclusion: In a porcine model, cardioplegic arrest with St. Thomas´ Hospital polarizing solution offered comparable myocardial protection and improved myocardial function (Paper I), preserved energy status (Paper II) and enhanced contractile efficiency (Paper III) in the early hours after weaning from cardiopulmonary bypass compared to St. Thomas´ Hospital No 2 blood cardioplegia

Kommunikasjon i endringsprosesser : en studie av en endringsprosess i SAS

Formålet med avhandlingen er å bidra til økt kunnskap om kommunikasjonens innvirkning på holdninger og atferd hos endringsmottaker underveis i endringsprosesser og dens utfall for organisasjonen. Rammeverket for studien er basert på teori om kommunikasjon i endringsprosesser. Vi har benyttet en forskningsmodell med tilhørende hypoteser for å teste teoretiske sammenhenger opp mot en konkret endringsprosess. Endringsprosessen kalles ”den kulturell turnaround” og foretas av flyselskapet Scandinavian Airlines System (SAS). For å trekke slutninger har vi foretatt en kvantitativ spørreundersøkelse samt intervju. Spørreundersøkelsen ble gjennomført og analysert ved hjelp av et statistisk analyseverktøy. Resultatene våre viser at kommunikasjon har en innvirkning på utfallet av endringsprosessen og for organisasjonen, ved at endringsmottaker utviler holdninger og atferd underveis i endringsprosessen. Funnene kan dermed ha implikasjoner for organisering og ledelse av endringsprosesser

Underpricing and long-run performance of Norwegian initial public offerings : An empirical investigation of factors that impacts short and longterm returns of Norwegian initial public offerings

In this master's thesis, we have investigated several factors that could account for the underpricing and long-term performance of initial public offerings in Norway. We used size, equity beta, and a PE/VC dummy variable as explanatory factors for underpricing. We extended the Fama-French (1992) multifactor model to account for liquidity and momentum in the long-run performance. We also utilize both cumulative abnormal returns (CAR) and buy-and-hold returns (BHR) for the long-run analysis. Our findings show that PE/VC-sponsored IPOs are more underpriced, but not at a statistically significant level. Size and risk do not impact the level of underpricing at a statistically significant level either. In terms of long-run performance, CAR exhibits underperformance of PE/VC-sponsored IPOs, with smaller firms underperforming to a larger extent. BHR results vary drastically over time between PE/VC and non-sponsored firms, but this seems to be a result of market dynamics as opposed to sponsoring. None of the risk-adjusted models return significant alphas, but value-weighted portfolios indicate slight underperformance for PE/VCsponsored IPOs. Covid-19 also had an influence on our results, as PE/VC-sponsored IPOs significantly outperformed non-sponsored IPOs for a short duration. Lastly, both equally- and value-weighted portfolios’ market exposure was influenced by the pandemic.nhhma

Å investere i volatilitet : egenskaper, marked og nytte i porteføljesammenheng

Utredningen tar for seg flere aspekter ved investering i volatilitet. For det første ser vi på de mest benyttede instrumentene for å oppnå en ren eksponering mot volatilitet, herunder volatilitetsfutures, volatilitetsopsjoner og varians-swapper. Vi forklarer derivatenes egenskaper, samt forskjeller og likheter mellom dem. Deretter følger en kartlegging av tidligere litteratur som tar for seg inkludering av volatilitetsinstrumenter i porteføljer bestående av andre aktiva. Vi går i dybden på fire av disse studiene. Den tidligere litteraturen viser seg å være preget av et stort mangfold av metoder og tilnærminger, med svært varierende resultater. Videre undersøker vi markedet for volatilitetsinstrumenter ved blant annet å samle inn primærdata fra markedsaktører i form av en spørreundersøkelse. Vi fokuserer på de forskjellige aktørenes motiver for å investere i volatilitetsinstrumenter. Basert på praksis i eksisterende litteratur, skiller vi mellom motivene spekulasjon, diversifisering og sikring. Vi fokuserer også på hvilke instrumenter aktørene benytter. Resultatene viser at forskjellige motiver for investering i volatilitet er utbredt blant aktørene, men at spekulasjon og sikring er hovedmotivene. I tillegg har vi vurdert nytten av å inkludere volatilitetsfutures i en aksjeportefølje ved bruk av en dynamisk, betinget optimaliseringsmodell foreslått av Brandt og Santa-Clara (2006). Vi tester modellen «in-sample» og «out-of-sample», for én og to investeringsperioder. Betingede variabler velges på grunnlag av hvorvidt de viser tegn til å predikere fremtidig avkastningsfordeling. Vi får blandede resultater. Den betingede enkeltperiodeporteføljen gir signifikant forbedring av risikojustert avkastning, sammenlignet med en ren aksjeportefølje «out-of-sample». Den betingede toperiodeporteføljen gir derimot svakest resultater av samtlige porteføljer «out-of-sample».nhhma

Økonomiske virkninger av avbestilling i entreprisekontrakter

En avbestilling innebærer at kontraktsforholdet ikke blir gjennomført som forutsatt, og spørsmålet som drøftes i oppgaven er hvilken innvirkning avbestillingen før på det økonomiske oppgjøret mellom byggherren og entreprenøren

Management Strategies for Enhanced Beef Production on Suckler Cow Farms

While around two thirds the Norwegian beef is produced on dairy cow farms, meat production on specialized beef farms has increased in recent years. The specialized beef industry consists of suckler cow herds producing calves, and farm operations that purchase weaned calves for fattening. A linear programming (LP) model of suckler cow herds, selling weaned calves at 200 days, was developed to study the influence of certain management strategies on profitability. The data were derived from the records of 31 suckler cow herds from three Norwegian regions. The feed costs for silage (roughly half of the feed), NH3-treated straw, concentrate and farm and range pastures were calculated and used as model input. In the model pasture could account for as much as half of the annual feed intake with spring calving on small British breeds and 30% with autumn calving on large continental breeds. In region 1 and 2 in south Norway, late harvesting of roughages and using NH3 treated straw was advantageous compared to earlier harvesting and less concentrates. The growth rate of calves was demonstrated to be an important parameter for the economy in both British and continental breeds. Shortening age at first calving to 2 years, and the calving interval to 12 months was profitable but the gains were small. Similarly, the front-end loading concept with 2/3 of the calves after the first ovulation period, and the remaining in the next, was profitable compared to a similar number (1/3) in three subsequent periods. The economics of a high or low replacement rate was also examined

Retten til erstatning for psykisk sjokk - En analyse av adekvanskravet når nærstående har bevitnet en skadevoldende handling gjennom multimedier

Master i rettsvitenskapJUS399MAJU

Simulations of feed intake, production output, and economic result within extensive and intensive suckler cow beef production systems

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Elsevier in Livestock Science on 24/08/2020.Available online: https://www.sciencedirect.com/science/article/pii/S1871141320305758?via%3DihubacceptedVersio

Estimation of breed and heterosis effects for cow productivity, carcass traits and income in beef × beef and dairy × beef crosses in commercial suckler cow production

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Taylor & Francis in Acta Agriculturae Scandinavia, Section A - Animal Science on 1 April 2020.Available online: 10.1080/09064702.2020.1746825This study aims to investigate calving difficulties, birth-, weaning- and carcass weight, herd life of cow, age at slaughter, average daily carcass gain, carcass conformation, carcass fatness and carcass income per carcass, kg or day, in Aberdeen Angus (A), Hereford (H), Charolais (C), Limousin (L), Simmental (S), Norwegian red (N) and their crosses, in order to evaluate crossbreeding strategies. Direct and maternal breed additive and heterosis effects and predicted phenotypic means were estimated with multiple regression using SAS. Crosses with N resulted in higher weaning weight and less calving difficulties than beef purebreds. Due to favourable maternal additive effects of N on carcass weight and -income, crosses with British breeds had higher performance than the purebreds. (A × C) × C had overall high performance due to beneficial maternal heterosis effects on calving difficulties and carcass weight. In conclusion, utilising profitable heterosis effects have potential in commercial production, but are dependent on production systems.acceptedVersio