Utilizing ubiquitous commodity graphics hardware for scientific computing

Current GPUs have many times the memory bandwidth and computing power compared to CPUs. The difference in performance is getting bigger as the evolution speed of the GPUs is higher than of the CPUs. This make it interesting to use the GPU for general purpose computing (GPGPU). I begin by looking at the architecture of the GPU, and some different techniques for programming on a GPU, including some of the available high-level languages. I have implemented the Mandelbrot computation on a cluster of GPUs (the HPDC display wall), and compared it against two different CPU implementations on the cluster. I have also implemented the Mandelbrot computation in both Cg and Brook, and compared the performance of the two languages. My experimental study shows that the GPU implementation of the Mandelbrot application is up to twice as fast as the load-balanced CPU implementation on the cluster of 28 computers, and up to 6 times faster on one computer

Multinasjonale selskapers skattemessige tilpasning av kapitalstruktur. En empirisk studie av norsk og britisk kontinentalsokkel

Denne utredningen tar for seg multinasjonale selskapers skattemessige tilpasning av kapitalstruktur. Ettersom rentekostnader, i motsetning til utbytte, vanligvis er fradragsberettiget på selskapets hånd, vil skattesystemene i de landene et multinasjonalt selskap opererer, være svært avgjørende for en slik tilpasning. Vi viser hvordan slike konsern minimerer sin totale skattebyrde ved å drive profittflytting mellom datterselskaper i ulike land. For å belyse i hvilken grad multinasjonale selskaper tilpasser sin kapitalstruktur i praksis, vil vi også gjøre en empirisk studie på multinasjonale petroleumsselskaper på norsk og britisk sokkel. Vi gjennomgår derfor skattereglene i disse landene grundig. Våre funn viser at multinasjonale petroleumsselskaper i høy grad tilpasser seg de skattemessige forskjellene som foreligger mellom norsk og britisk sokkel. Det foreligger betydelige forskjeller i bruken av gjeld mellom selskaper på norsk og britisk sokkel. Et norsk regime med høye skatter favoriserer bruk av gjeld. I tillegg ser man også at det foreligger egenskaper på konsernnivå som har betydning for gjeldsallokeringen. Våre funn impliserer dermed viktigheten av myndighetenes skattepolitikk i land hvor det foregår utvinning av petroleum

Dark neutrino interactions make gravitational waves blue

New interactions of neutrinos can stop them from free streaming in the early Universe even after the weak decoupling epoch. This results in the enhancement of the primordial gravitational wave amplitude on small scales compared to the standard $\Lambda$CDM prediction. In this paper we calculate the effect of dark matter neutrino interactions in CMB tensor $B$-modes spectrum. We show that the effect of new neutrino interactions generates a scale or $\ell$ dependent imprint in the CMB $B$-modes power spectrum at $\ell \gtrsim 100$. In the event that primordial $B$-modes are detected by future experiments, a departure from scale invariance, with a blue spectrum, may not necessarily mean failure of simple inflationary models but instead may be a sign of non-standard interactions of relativistic particles. New interactions of neutrinos also induce a phase shift in the CMB B-mode power spectrum which cannot be mimicked by simple modifications of the primordial tensor power spectrum. There is rich information hidden in the CMB $B$-modes spectrum beyond just the tensor to scalar ratio.Comment: 31 pages, 10 figures. Version published in Phys. Rev.

Annual report on health monitoring of wild anadromous salmonids in Norway 2021 - Screening of Atlantic salmon (Salmo salar) postsmolts for viral infections

Havforskningsinstituttet har undersøkt utbredelsen av infeksiøs lakseanemi virus (ILAV) og salmonid alfavirus (SAV, PD-virus) infeksjoner i utvandrende vill atlantisk postsmolt fanget i 2020 i tre fjordsystemer lokalisert i tre akvakultur produksjonsområder (PO3, 5, 12). Fisken ble samlet inn som en del av NALO-programmet i de ytre delene av fjordene; Hardangerfjorden (N = 100), Romsdalsfjorden (N = 100) og Altafjorden (N = 100) ved tråling i perioden mai-juni. SAV ble påvist i én postsmolt fra Hardangerfjorden og ILAV i én smolt fra Altafjorden. Høy Ct-verdi (37,6) i den SAV-positive fisken kan imidlertid tyde på et falskt positivt resultat. ILAV påvisningen var sannsynligvis av den apatogene HPR0-varianten av viruset. Funnene fra den nåværende rapporten indikerer en svært lav forekomst av disse virusene i vill migrerende postsmolt av laks. Disse funnene utfyller og støtter våre tidligere rapporterte data, og kan antyde at utbredelsen av ILAV- eller SAV-infeksjoner i villaks postsmolt ikke er signifikant påvirket av forekomsten av disse infeksjonene i fiskeoppdrett.publishedVersio

Annual report on health monitoring of wild anadromous salmonids in Norway 2020 - Screening of wild Atlantic salmon (Salmo salar) postsmolts for viral infections

The Institute of Marine Research has investigated the prevalence of infectious salmon anaemia virus (ISAV) and salmonid alphavirus (SAV, PD-virus) infections in migrating wild Atlantic salmon postsmolts captured in 2019 in three fjord systems located in three aquaculture production areas (PO2-4). These areas have had a sporadic case of ISA and a stable high incidence rate of PD, as well as a very high aquaculture intensity. The fish were collected as part of the national salmon lice monitoring program in the outer parts of the Bokna (N=132), Hardanger (N=110) and Sogne (N=110) fjords by trawling during the period May-June. ISAV was detected in two postsmolts from Hardanger fjord and SAV in one smolt from Sogne fjord. The Ct-value of SAV-positive fish was very high (38.9) which may suggest a false positive result. The findings from the current report indicate a very low prevalence of these viruses in wild migrating postsmolts. These findings complement and corroborate our previously reported data and may suggest that prevalence of ISAV or SAV infections in wild salmon postsmolts are not significantly influenced by the occurrence of these infections in fish farming.publishedVersio

Predictors of rate of change for children and youth with emotional disorders: a naturalistic observational study

Published version. Source at http://dx.doi.org/10.1186/s13034-016-0098-3 Background: To examine demographic and clinical characteristics as potential predictors of change for children and youth with emotional disorders treated at two child and adolescent mental health outpatient services (CAMHS) in Norway. Methods: The study was of naturalistic observational type with “treatment as usual” (TAU). The sample consisted of 84 children and youth with emotional disorders. The Health of the Nation Outcome Scale (HONOSCA), and the Children’s Global Assessment Scale (CGAS) were administered at intake (T0), during the assessment (T1) and approximately six months after assessment (T2). Change was analysed by means of the linear mixed models procedure. Results: For the HONOSCA total score, youths with a diagnosis of depression had statistically higher symptom severity levels at baseline and significantly lower change rates as compared to youths with an anxiety disorder. Conclusions: The current study adds to the limited knowledge of predictors of rate of change for children and adolescents with emotional disorders treated within CAMHS. Our results point to a special need to improve clinical care for depressed children and adolescents. Important limitations comprising the external validity of the study concern missing data, a small study sample, and lack of information regarding the content and extent of the service provided

Effects of environmental stress on mRNA expression levels of seven genes related to oxidative stress and growth in Atlantic salmon Salmo salar L. of farmed, hybrid and wild origin

Background: Ten generations of domestication selection has caused farmed Atlantic salmon Salmo salar L. to deviate from wild salmon in a range of traits. Each year hundreds of thousands of farmed salmon escape into the wild. Thus, interbreeding between farmed escapees and wild conspecifics represents a significant threat to the genetic integrity of wild salmon populations. In a previous study we demonstrated how domestication has inadvertently selected for reduced responsiveness to stress in farmed salmon. To complement that study, we have evaluated the expression of seven stress-related genes in head kidney of salmon of farmed, hybrid and wild origin exposed to environmentally induced stress. Results: In general, the crowding stressor used to induce environmental stress did not have a strong impact on mRNA expression levels of the seven genes, except for insulin-like growth factor-1 (IGF-1) that was downregulated in the stress treatment relative to the control treatment. mRNA expression levels of glutathione reductase (GR), Cu/Zn superoxide dismutase (Cu/Zn SOD), Mn superoxide dismutase (Mn SOD), glutathione peroxidase (GP) and IGF-1 were affected by genetic origin, thus expressed significantly different between the salmon of farmed, hybrid or wild origin. A positive relationship was detected between body size of wild salmon and mRNA expression level of the IGF-1 gene, in both environments. No such relationship was observed for the hybrid or farmed salmon. Conclusion: Farmed salmon in this study displayed significantly elevated mRNA levels of the IGF-1 gene relative to the wild salmon, in both treatments, while hybrids displayed a non additive pattern of inheritance. As IGF-1 mRNA levels are positively correlated to growth rate, the observed positive relationship between body size and IGF-1 mRNA levels detected in the wild but neither in the farmed nor the hybrid salmon, could indicate that growth selection has increased IGF-1 levels in farmed salmon to the extent that they may not be limiting growth rate.publishedVersio

Annual report on health monitoring of wild anadromous salmonids in Norway 2022 - Screening of Atlantic salmon (Salmo salar) postsmolts from Boknafjorden, Hardangerfjorden and Romsdalsfjorden for viral infections

The Institute of Marine Research has investigated the prevalence of infectious salmon anaemia virus (ISAV), salmonid alphavirus (SAV, PD-virus), piscine orthoreovirus 1 (PRV-1), piscine myocarditis virus (PMCV) and infectious pancreatic necrosis virus (IPNV) infections in migrating wild Atlantic salmon postsmolts captured in 2021 in three fjord systems located in three aquaculture production areas (PO2, 3 and 5). The fish were collected as part of the national salmon lice monitoring program in the outer parts of Boknafjord (N = 50), Hardangerfjord (N = 57) and Romsdalsfjord (N = 73) by trawling during the period May-June. SAV was detected in 2 postsmolts from Romsdalsfjord. PRV-1 was detected in 11 (6%) of postsmolts (8 from Boknafjord, 1 from Hardangerfjord and 2 from Romsdalsfjord). Low concentrations of PMCV-RNA were detected in 19 (11 %) of postsmolts (13 from Boknafjord and 6 from Romsdalsfjord). ISAV and IPNV were not detected in any of the test fish. Generally, the virus-positive fish had high Ct-values which may indicate very low virus concentrations. The results in the current report showed that migrating postsmolts from fjords had a very low occurrence of virus infections common in Norwegian aquaculture. These findings complement and corroborate our previously reported data and may suggest that prevalence virus infections in wild salmon postsmolts is not significantly influenced by the occurrence of these infections in fish farming.Annual report on health monitoring of wild anadromous salmonids in Norway 2022 - Screening of Atlantic salmon (Salmo salar) postsmolts from Boknafjorden, Hardangerfjorden and Romsdalsfjorden for viral infectionspublishedVersio

Clinical expressions, characteristics and treatments of confirmed COVID-19 in nursing home residents : a systematic review

Background: The coronavirus 2019 (COVID-19) pandemic has led to a high rate of infections, frequent outbreaks, and high mortality rates in nursing homes (NH) worldwide. To protect and improve the treatment and care of the vulnerable NH population, it is pivotal to systematise and synthesise data from cases of COVID-19 among NH residents. In our systematic review, we therefore aimed to describe the clinical expressions, characteristics, and treatments of NH residents confirmed to have COVID-19. Methods: We conducted two comprehensive literature searches in several electronic databases: (1) PubMed, (2) CINAHL, (3) AgeLine, (4) Embase, and (5) PsycINFO in April and July 2021. Of the 438 articles screened, 19 were included in our sample, and we used the Newcastle–Ottawa Assessment Scale to assess the quality of the reported studies. A weighted mean (Mweighted), was calculated to account for the large variation in sample sizes of the studies, and due to heterogeneity among the studies, we report our findings in a narrative synthesis. Results: According to the mean weights (Mweighted), common symptoms and signs in NH residents confirmed to have COVID-19 were fever (53.7%), cough (56.5%), hypoxia (32.3%), and delirium or confusion (31.2%). Common comorbidities were hypertension (78.6%), dementia or cognitive impairment (55.3%), and cardiovascular diseases (52.0%). Six studies presented data concerning medical and pharmacological treatments, such as inhalers, oxygen supplementation, anticoagulation, and parenteral/enteral fluids or nutrition. The treatments were used to improve outcomes, as part of palliative care, or as end-of-life treatment. Transfers to hospital for NH residents with confirmed COVID-19 were reported in six of the included studies, and the rate of hospital transfers ranged from 6.9% to 50% in this population. In the 17 studies reporting mortality, 40.2% of the NH residents died during the studies’ observation periods. Conclusions: Our systematic review allowed us to summarise important clinical findings about COVID-19 among NH residents and to identify the population’s risk factors for serious illness and death caused by the disease. However, the treatment and care of NH residents with severe COVID-19 warrant further investigation.publishedVersio