Norske rederiers multinasjonale virksomhet

Dette arbeidsnotatet inngår i prosjektet ” Norske rederiers multinasjonale virksomhet” som er finansiert av NFR. Hensikten med prosjektet er å studere konsekvenser og sammensetningen av rederinæringens multinasjonale virksomhet generelt, og utenlandske direkteinvesteringer spesielt. Hauge og Stokke har gjennomført casestudier av to tradisjonsrike norske rederier og en utstyrleverandør til den maritime næringen, og analyserer de strategiske vurderingene som disse selskapene foretok i forkant av at de etablerte seg i Singapore. Konsekvensene av utenlandsinvesteringene blir også analysert, og funnene knyttes opp mot eksisterende teori på området. Hauge og Stokke identifiserte både lokaliserings-, eierskaps- og internaliseringsfordeler. Motivene for å lokalisere seg i Singapore, i stedet for å eksportere fra Norge, var ikke ensartet. To av selskapene la avgjørende vekt på at Singapore gir god tilgang til et stort marked, mens det siste selskapet etablerte seg i Singapore for å få gunstigere og mer stabile rammebetingelse. Alle selskapene hadde eierskapsfordeler i form av bedriftsspesifikk kunnskap som de fant det hensiktsmessig å internalisere, selv om ett av selskapene vurderte så vel lisensiering av produksjonen til etablerte bedrifter i Singapore som joint venture. Ex post vurderingene er i hovedsak positive, og spesielt pekte et av selskapene på at de ved å være etablert i Singapore raskt oppfattet signalene om en finansiell krise i Asia i 1997. Hauge og Stokke er siviløkonomstudenter ved NHH

Matsvinn: ambivalente studenter. En kvalitativ sosiologisk studie av studenters holdninger og handlinger knyttet til matsvinn

Denne masteroppgaven handler om studenter og deres forhold til kasting av mat. I forbrukersamfunnet kastes det store mengder spiselig mat, og som en konsekvens av alt matsvinnet følger betydelige klimagassutslipp. Målet med oppgaven er derfor både å belyse enkeltindividers ansvar for å begrense sitt matsvinn, men også å se på hvordan sosiale strukturer kan virke muliggjørende og begrensende. Jeg ser på ulike praksiser som kan fremprovosere og redusere matsvinn, og undersøker hvordan ulike sosiale faktorer i studenters hverdag kan påvirke deres praksiser. Oppgavens empiri baserer seg på ti kvalitative intervjuer med fulltidsstudenter i starten av 20-årene. Problemstillingen og forskningsspørsmålene blir belyst teoretisk gjennom Bente Halkiers ambivalensbegrep, Erving Goffmans dramaturgiske samfunnssyn, samt Pierre Bourdieus habitusbegrep som utgangspunkt for analytisk tilnærming. Et av oppgavens hovedfunn er at studentene er opptatte av å framstille seg selv som miljøbevisste, og at de ønsker å unngå å kaste spiselig mat foran andre. For å framstå som troverdige aktører, blir inntrykkskontrollen en sentral sosial ferdighet som studentene må mestre. I sosiale interaksjoner forhandles kollektive verdier frem, og disse verdiene gjenspeiler ikke nødvendigvis enkeltindividets egne verdier. Studentenes økologiske habitus kan også overskride deres uttalte verdier og holdninger, noe som kan føre til at de havner i en ambivalent tilstand. Studentenes vurdering av matens verdi blir sentral for hvorvidt maten utnyttes eller ikke. Intervjuene viser at studentene hovedsakelig motiveres av økonomiske årsaker, og at billig mat i større grad kastes enn dyr mat. Maten kan også tillegges en følelsesverdi som gjør den vanskeligere å kaste. I tillegg til billig mat, tillegges delvis utnyttet mat og mat med manglende bruksområde lav verdi. Når studentene finner det ubeleilig å skulle utnytte maten med lav verdi, kan de havne i en ambivalent tilstand hvor de dras mellom å handle utfra et altruistisk eller et egoistisk ståsted. Jeg anvender Bourdieus habitusbegrep og hans forståelse av kulturell kapital til å belyse viktigheten av studentenes vaner og rutiner for mathåndtering fra oppveksten. Samtidig som at praksisene i stor grad er inkorporert i studentenes habitus, bør ikke deres individuelle og rasjonelle målsetninger overses

Low rank positive partial transpose states and their relation to product vectors

It is known that entangled mixed states that are positive under partial transposition (PPT states) must have rank at least four. In a previous paper we presented a classification of rank four entangled PPT states which we believe to be complete. In the present paper we continue our investigations of the low rank entangled PPT states. We use perturbation theory in order to construct rank five entangled PPT states close to the known rank four states, and in order to compute dimensions and study the geometry of surfaces of low rank PPT states. We exploit the close connection between low rank PPT states and product vectors. In particular, we show how to reconstruct a PPT state from a sufficient number of product vectors in its kernel. It may seem surprising that the number of product vectors needed may be smaller than the dimension of the kernel.Comment: 29 pages, 4 figure

A case-control study of linear energy transfer and relative biological effectiveness related to symptomatic brainstem toxicity following pediatric proton therapy

Background and purpose A fixed relative biological effectiveness (RBE) of 1.1 (RBE1.1) is used clinically in proton therapy even though the RBE varies with properties such as dose level and linear energy transfer (LET). We therefore investigated if symptomatic brainstem toxicity in pediatric brain tumor patients treated with proton therapy could be associated with a variable LET and RBE. Materials and methods 36 patients treated with passive scattering proton therapy were selected for a case-control study from a cohort of 954 pediatric brain tumor patients. Nine children with symptomatic brainstem toxicity were each matched to three controls based on age, diagnosis, adjuvant therapy, and brainstem RBE1.1 dose characteristics. Differences across cases and controls related to the dose-averaged LET (LETd) and variable RBE-weighted dose from two RBE models were analyzed in the high-dose region. Results LETd metrics were marginally higher for cases vs. controls for the majority of dose levels and brainstem substructures. Considering areas with doses above 54 Gy(RBE1.1), we found a moderate trend of 13% higher median LETd in the brainstem for cases compared to controls (P =.08), while the difference in the median variable RBE-weighted dose for the same structure was only 2% (P =.6). Conclusion Trends towards higher LETd for cases compared to controls were noticeable across structures and LETd metrics for this patient cohort. While case-control differences were minor, an association with the observed symptomatic brainstem toxicity cannot be ruled out.publishedVersio

Influence of beam pruning techniques on LET and RBE in proton arc therapy

Introduction: Proton arc therapy (PAT) is an emerging treatment modality that holds promise to improve target volume coverage and reduce linear energy transfer (LET) in organs at risk. We aimed to investigate if pruning the highest energy layers in each beam direction could increase the LET in the target and reduce LET in tissue and organs at risk (OAR) surrounding the target volume, thus reducing the relative biological effectiveness (RBE)-weighted dose and sparing healthy tissue. Methods: PAT plans for a germinoma, an ependymoma and a rhabdomyosarcoma patient were created in the Eclipse treatment planning system with a prescribed dose of 54 Gy(RBE) using a constant RBE of 1.1 (RBE1.1). The PAT plans was pruned for high energy spots, creating several PAT plans with different amounts of pruning while maintaining tumor coverage, denoted PX-PAT plans, where X represents the amount of pruning. All plans were recalculated in the FLUKA Monte Carlo software, and the LET, physical dose, and variable RBE-weighted dose from the phenomenological Rørvik (ROR) model and an LET weighted dose (LWD) model were evaluated. Results and discussion: For the germinoma case, all plans but the P6-PAT reduced the mean RBE-weighted dose to the surrounding healthy tissue compared to the PAT plan. The LET was increasingly higher within the PTV for each pruning iteration, where the mean LET from the P6-PAT plan was 1.5 keV/μm higher than for the PAT plan, while the P4- and P5-PAT plans provided an increase of 0.4 and 0.7 keV/μm, respectively. The other plans increased the LET by a smaller margin compared to the PAT plan. Likewise, the LET values to the healthy tissue were reduced for each degree of pruning. Similar results were found for the ependymoma and the rhabdomyosarcoma case. We demonstrated a PAT pruning technique that can increase both LET and RBE in the target volume and at the same time decreased values in healthy tissue, without affecting the target volume dose coverage.publishedVersio

Influence of beam pruning techniques on LET and RBE in proton arc therapy

IntroductionProton arc therapy (PAT) is an emerging treatment modality that holds promise to improve target volume coverage and reduce linear energy transfer (LET) in organs at risk. We aimed to investigate if pruning the highest energy layers in each beam direction could increase the LET in the target and reduce LET in tissue and organs at risk (OAR) surrounding the target volume, thus reducing the relative biological effectiveness (RBE)-weighted dose and sparing healthy tissue.MethodsPAT plans for a germinoma, an ependymoma and a rhabdomyosarcoma patient were created in the Eclipse treatment planning system with a prescribed dose of 54 Gy(RBE) using a constant RBE of 1.1 (RBE1.1). The PAT plans was pruned for high energy spots, creating several PAT plans with different amounts of pruning while maintaining tumor coverage, denoted PX-PAT plans, where X represents the amount of pruning. All plans were recalculated in the FLUKA Monte Carlo software, and the LET, physical dose, and variable RBE-weighted dose from the phenomenological Rørvik (ROR) model and an LET weighted dose (LWD) model were evaluated.Results and discussionFor the germinoma case, all plans but the P6-PAT reduced the mean RBE-weighted dose to the surrounding healthy tissue compared to the PAT plan. The LET was increasingly higher within the PTV for each pruning iteration, where the mean LET from the P6-PAT plan was 1.5 keV/μm higher than for the PAT plan, while the P4- and P5-PAT plans provided an increase of 0.4 and 0.7 keV/μm, respectively. The other plans increased the LET by a smaller margin compared to the PAT plan. Likewise, the LET values to the healthy tissue were reduced for each degree of pruning. Similar results were found for the ependymoma and the rhabdomyosarcoma case. We demonstrated a PAT pruning technique that can increase both LET and RBE in the target volume and at the same time decreased values in healthy tissue, without affecting the target volume dose coverage

Differential contributions of specimen types, culturing, and 16S rRNA sequencing in diagnosis of prosthetic joint infections

ABSTRACT Prosthetic joint failure is mainly caused by infection, aseptic failure (AF), and mechanical problems. Infection detection has been improved with modified culture methods and molecular diagnostics. However, comparisons between modified and conventional microbiology methods are difficult due to variations in specimen sampling. In this prospective, multidisciplinary study of hip or knee prosthetic failures, we assessed the contributions of different specimen types, extended culture incubations, and 16S rRNA sequencing for diagnosing prosthetic joint infections (PJI). Project specimens included joint fluid (JF), bone biopsy specimens (BB), soft-tissue biopsy specimens (STB), and swabs (SW) from the prosthesis, collected in situ , and sonication fluid collected from prosthetic components (PC). Specimens were cultured for 6 (conventional) or 14 days, and 16S rRNA sequencing was performed at study completion. Of the 156 patients enrolled, 111 underwent 114 surgical revisions (cases) due to indications of either PJI ( n = 43) or AF ( n = 71). Conventional tissue biopsy cultures confirmed PJI in 28/43 (65%) cases and refuted AF in 3/71 (4%) cases; one case was not evaluable. Based on these results, minor diagnostic adjustments were made. Fourteen-day cultures of JF, STB, and PC specimens confirmed PJI in 39/42 (93%) cases, and 16S rRNA sequencing confirmed PJI in 33/42 (83%) cases. One PJI case was confirmed with 16S rRNA sequencing alone and five with cultures of project specimens alone. These findings indicated that JF, STB, and PC specimen cultures qualified as an optimal diagnostic set. The contribution of sequencing to diagnosis of PJI may depend on patient selection; this hypothesis requires further investigation. </jats:p