Variability in modelled Arctic Sea-Ice Volume

In this thesis, the Arctic sea ice volume and thickness evolution over the time period 1850-2100 is analysed. The analysed data is provided by the CMIP5 climate models, which contributed their output for the IPCC Fifth Assessment. The results were compared to the reanalysis data series PIOMAS. Three RCP projections, with different greenhouse gas emission scenarios, were used for the time period 2006- 2100. The change in seasonal cycle was investigated throughout the time period and for the three RCP scenarios. Two of the models were evaluated in more detail, these were MPI-ESM and EC-EARTH. Maps showing the thickness change, according to the two models MPI-ESM and EC-EARTH, were made. The evolution of the sea ice volume shows a dependence on the change in radiative forcing, thus the emissions of greenhouse gases. For the high emission scenario, ice-free conditions in September are reached before 2100. The models are able to reproduce some characteristics of the sea-ice, but are generally underestimating the total volume. The most important finding is that none of the models is able to reproduce the rapid decrease in volume which is seen in PIOMAS and supported by observations. This indicates that there is some component missing in the models. The sea-ice retreat can also be expected to go faster than seen in the models if greenhouse emissions are not decreased. The reduction would, according to the models, slow down when the ice gets thinner, since thick ice reacts stronger than thin to changes in radiative forcing. The models show that the sea-ice would have some quasi-equilibrium, depending on the climate, and no so called tipping point after which the sea-ice would not be able to recover. It would then still be possible for us to stop further sea-ice reduction

Smärtlindring i samband med vaccination av fisk

Vaccination of fish can be assumed to cause pain. This study was designed to see if we can minimize the suffering of fish following vaccination. Fishes are cold-blooded animals and thus more primitive than warm-blooded animals. Despite this, many organs, e.g. the nervous system, have the same basic structure as that of other vertebrates. The fibre system for conducting pain is more diffuse than in humans. No specific pain conducting tract seems necessary for pain transmission. All ethical rules and laws for animals include fish, but pain killing is still not common in fish production. Prostaglandins and bradykinin are substances which are released in the inflammatory process and cause pain. Vaccination causes peritonitis and adherence between organs and the abdominal wall (scarring). The peritonitis can be assumed to cause pain, which may be one reason why the fish stops feeding for several days following vaccination. Many analgesics inhibit the synthesis of prostaglandin, and thus inhibit both pain and inflammation. The local anasthetics used to immobilize fish are given in the water and taken up via the gills. This gives systemic effects. Atlantic salmon, Salmo salar, was used. 1980 parr were allocated in 14 tubs. Later another 400 parr in two tubs were used. The fish had free access to feed and had continuous daylight. The study was split into two parts. In the first part, two methods for measurement of feed intake was evaluated. In the second part different feeding models (starvation/feeding) and Aqui-S (isoeugenol, which probably diminishes the pain), was used to see if we could affect the time for recovery following vaccination. Before vaccination all groups besides the feed group were starved for two days. Following vaccination, the fish was fed again, except for the starvation group, that was not fed until day three after vaccination. The first feeding day the fish was fed for 10 hours. The pain level was measured as feed intake in percent of biomass, since feed intake is a very good indicator of the well-being of the fish. Before vaccination the fish was sedated with benzocain, the routine sedative at vaccination. The vaccine used was Norvax Compact 6 vet. for furunculosis, cold water vibriosis, vibriosis, winter wounds and IPN. The injection dose was 0,1 ml. This dose is used independent of the size of the fish. The group of fish that was fed all the way through the study recovered fastest; followed by the group that was starved for three days following vaccination. The Aqui-SÔgroup recovered much slower, and the feed intake was significantly lower than for the feed- and starving groups. The control group recovered more slowly than the starvation group but faster than the Aqui-S group. The Aqui-SÔgroup had most adherences, and the feed group had the least. The study clearly shows that starvation prior to vaccination of the fish is wrong. The pharmacological effects of Aqui-S need to be evaluated and more experiments need to be done before we can come to any conclusions about its effectiveness as an analgesic.Det finns anledning att tro att vaccinering av fisk orsakar smärta. Målet med denna studie var att se om vi kunde minska fiskens lidande efter vaccination. Fisken är ett kallblodigt djur och mer primitivt än varmblodiga djur, men bl.a. nervsystemet har samma basala byggnad som hos övriga vertebrater. Smärtfibersystemet är dock mer diffust än hos oss, och ingen specifik smärtledningsbana verkar vara nödvändig för smärtöverföring. Alla djuretiska regler och lagar gäller även för fisk, men smärtlindring är ändå ett eftersatt område inom fiskerinäringen. Smärta medieras av bl.a. prostaglandiner och bradykinin, ämnen som också är aktiva i den inflammatoriska processen. Vaccinering framkallar en inflammation, ofta med adherenser som följd. Fisken slutar äta dagarna efter vaccinering, vilket tyder på att inflammationen orsakar smärta. Många analgesipreparat hämmar prostaglandinsyntesen, och skyddar på så sätt mot både smärta och inflammation. De (lokal)anestesi- och analgesipreparat som används på fisk tillförs via vattnet och tas upp över gälarna. Därmed påverkas hela kroppen. Fisken som användes är Atlantlax, Salmo salar. Initialt användes 1980 fiskar, fördelade på 14 kar, och senare ytterligare 400 st. fördelade på två kar. Fisken utfodrades 24 timmar om dygnet och hade också belysning dygnet runt. Försöket delades upp i två delar. Under den första delen utvärderades olika metoder för mätning av foderintag. Under den andra delen, vaccinationsförsöket, undersöktes om olika utfodringsmodeller (svält/full utfodring) eller Aqui-S (isoeugenol, trolig smärtlindrare), kunde ha någon effekt på återhämtningen efter vaccination. Inför vaccinering svältes alla grupper utom fodergruppen under två dygn. Efter utförd vaccinering utfodrades fisken igen, utom svältgruppen som inte utfodrades förrän dag tre efter vaccinering. Denna första utfodringsdag fick fisken foder under 10 timmar. För att registrera fiskens återhämtning användes foderintag i procent av biomassan, eftersom foderintaget är en mycket bra indikator på hur fisken mår. Inför vaccineringen sederades fisken med benzocain. Vaccinet som användes var Norvax Compact 6 vet. mot furunkulos, kallvattenvibrios, vibrios, vintersår och IPN. Injektionsdosen var 0,1 ml. Denna dos används oavsett fiskens storlek. Den fisk som utfodrades genom hela försöket återhämtade sig snabbast, tätt följd av svältgruppen. Aqui-Sgruppen återhämtade sig långsammast och foderintaget var signifikant lägre än foder- och svältgruppernas foderintag. Kontrollgruppen hamnade mellan svältgruppen och Aqui-Sgruppen i återhämtning. Aqui-Sgruppen hade också mest adherenser, medan fodergruppen hade minst adherenser. Försöket visar att det är olämpligt att svälta fisken inför vaccinering, men vad gäller Aqui-S behöver fler försök utföras och substansens farmakologiska effekter utredas innan några riktiga slutsatser kan dras

Sprickor i anläggningskonstruktioner av betong : bakomliggande orsaker, bedömning och möjliga åtgärder

Inom den Svenska byggindustrin har Betonghandboken Material länge tjänat som ett naturligt val av hjälpmedel för ingenjörer som har stött på ett betongtekniskt problem. Den senaste utgåvan av Betonghandboken material publicerades 1994. Detta gör att många av de kunskaper vi har idag inom betongområdet går outnyttjade då man använder sig av Betonghandboken. Det finns ett behov att sammanfatta de kunskaper som finns gällande sprickorsaker, bedömning och reparation och presentera dem på ett överskådligt sätt. Studien syftar till att beskriva orsaker, bedömning och möjliga åtgärder till sprickbildning i anläggningskonstruktioner av betong samt utreda för och nackdelar med de olika reparationsmetoder och material som finns tillgängliga på dagens marknad. Resultatet presenteras i form av en modell för hantering av sprickor i anläggningskonstruktioner av betong. Denna modell är användbar som ett hjälpmedel för entreprenörer vid bedömning av sprickor och val av reparationsmetoder. Dock bör det slutgiltiga valet av reparationsprodukt göras i samråd med en materialleverantör

The Nordic Subpopulation Research Programme: prediction of treatment outcome in patients with low back pain treated by chiropractors - does the psychological profile matter?

<p>Abstract</p> <p>Background</p> <p>It is clinically important to be able to select patients suitable for treatment and to be able to predict with some certainty the outcome for patients treated for low back pain (LBP). It is not known to what degree outcome among chiropractic patients is affected by psychological factors.</p> <p>Objectives</p> <p>To investigate if some demographic, psychological, and clinical variables can predict outcome with chiropractic care in patients with LBP.</p> <p>Methods</p> <p>A prospective multi-center practice-based study was carried out, in which demographic, clinical and psychological information was collected at base-line. Outcome was established at the 4^thvisit and after three months. The predictive value was studied for all base-line variables, individually and in a multivariable analysis.</p> <p>Results</p> <p>In all, 55 of 99 invited chiropractors collected information on 731 patients. At the 4^thvisit data were available on 626 patients and on 464 patients after 3 months. Fee subsidization (OR 3.2; 95% CI 1.9-5.5), total duration of pain in the past year (OR 1.5; 95% CI 1.0-2.2), and general health (OR 1.2; 95% CI 1.1-1.4) remained in the final model as predictors of treatment outcome at the 4^thvisit. The sensitivity was low (12%), whereas the specificity was high (97%). At the three months follow-up, duration of pain in the past year (OR 2.1; 95% CI 1.4-3.1), and pain in other parts of the spine in the past year (OR1.6; 1.1-2.5) were independently associated with outcome. However, both the sensitivity and specificity were relatively low (60% and 50%). The addition of the psychological variables did not improve the models and none of the psychological variables remained significant in the final analyses. There was a positive gradient in relation to the number of positive predictor variables and outcome, both at the 4^thvisit and after 3 months.</p> <p>Conclusion</p> <p>Psychological factors were not found to be relevant in the prediction of treatment outcome in Swedish chiropractic patients with LBP.</p

Analyzing repeated data collected by mobile phones and frequent text messages. An example of Low back pain measured weekly for 18 weeks

BACKGROUND: Repeated data collection is desirable when monitoring fluctuating conditions. Mobile phones can be used to gather such data from large groups of respondents by sending and receiving frequently repeated short questions and answers as text messages. The analysis of repeated data involves some challenges. Vital issues to consider are the within-subject correlation, the between measurement occasion correlation and the presence of missing values. The overall aim of this commentary is to describe different methods of analyzing repeated data. It is meant to give an overview for the clinical researcher in order for complex outcome measures to be interpreted in a clinically meaningful way. METHODS: A model data set was formed using data from two clinical studies, where patients with low back pain were followed with weekly text messages for 18 weeks. Different research questions and analytic approaches were illustrated and discussed, as well as the handling of missing data. In the applications the weekly outcome “number of days with pain” was analyzed in relation to the patients’ “previous duration of pain” (categorized as more or less than 30 days in the previous year). Research questions with appropriate analytical methods 1: How many days with pain do patients experience? This question was answered with data summaries. 2: What is the proportion of participants “recovered” at a specific time point? This question was answered using logistic regression analysis. 3: What is the time to recovery? This question was answered using survival analysis, illustrated in Kaplan-Meier curves, Proportional Hazard regression analyses and spline regression analyses. 4: How is the repeatedly measured data associated with baseline (predictor) variables? This question was answered using generalized Estimating Equations, Poisson regression and Mixed linear models analyses. 5: Are there subgroups of patients with similar courses of pain within the studied population? A visual approach and hierarchical cluster analyses revealed different subgroups using subsets of the model data. CONCLUSIONS: We have illustrated several ways of analysing repeated measures with both traditional analytic approaches using standard statistical packages, as well as recently developed statistical methods that will utilize all the vital features inherent in the data

The Nordic back pain subpopulation program: predicting outcome among chiropractic patients in Finland

<p>Abstract</p> <p>Background</p> <p>In a previous Swedish study it was shown that it is possible to predict which chiropractic patients with persistent LBP will not report definite improvement early in the course of treatment, namely those with LBP for altogether at least 30 days in the past year, who had leg pain, and who did not report definite general improvement by the second treatment. The objectives of this study were to investigate if the predictive value of this set of variables could be reproduced among chiropractic patients in Finland, and if the model could be improved by adding some new potential predictor variables.</p> <p>Methods</p> <p>The study was a multi-centre prospective outcome study with internal control groups, carried out in private chiropractic practices in Finland. Chiropractors collected data at the 1st, 2^ndand 4^thvisits using standardized questionnaires on new patients with LBP and/or radiating leg pain. Status at base-line was identified in relation to pain and disability, at the 2^ndvisit in relation to disability, and "definitely better" at the 4^thvisit in relation to a global assessment. The Swedish questionnaire was used including three new questions on general health, pain in other parts of the spine, and body mass index.</p> <p>Results</p> <p>The Swedish model was reproduced in this study sample. An alternative model including leg pain (yes/no), improvement at 2^ndvisit (yes/no) and BMI (underweight/normal/overweight or obese) was also identified with similar predictive values. Common throughout the testing of various models was that improvement at the 2^ndvisit had an odds ratio of approximately 5. Additional analyses revealed a dose-response in that 84% of those patients who fulfilled none of these (bad) criteria were classified as "definitely better" at the 4^thvisit, vs. 75%, 60% and 34% of those who fulfilled 1, 2 or all 3 of the criteria, respectively.</p> <p>Conclusion</p> <p>When treating patients with LBP, at the first visits, the treatment strategy should be different for overweight/obese patients with leg pain as it should be for all patients who fail to improve by the 2^ndvisit. The number of predictors is also important.</p

Översikt, riskbedömning och förslag på åtgärder för puckellax (Oncorhynchus gorbuscha)

Puckellaxen (Oncorhynchus gorbuscha) tillhör ett släkte med tolv arter som brukar kallas stillahavslaxar. Flera arter inom släktet, däribland puckellaxen, är semelpara, d.v.s. de leker endast en gång och dör efter leken. Puckellaxen är den minsta av stillahavslaxarna och är i sitt ursprungsområde i Stilla havet den talrikaste. Flera av arterna i släktet, däribland puckellaxen, har introducerats på olika platser i världen – utanför arternas naturliga utbredningsområde. Det finns en befogad farhåga att invasiva främmande arter ska ha negativ påverkan på inhemska arter. En sammanställning som gjordes 2004 visade att invasiva arter är inblandade direkt eller indirekt i 6 % av alla utdöende eller kraftiga populationsminskningar av inhemska arter. I Sverige finns det idag ca 2000 introducerade arter av vilka 350 är klassificerade som invasiva, d.v.s. de hotar den biologiska mångfalden och ekosystemtjänster. Puckellaxen har på senare tid, framförallt under 2017, fångats eller observerats längs norska kusten, den svenska västkusten, Jylland i Danmark och även i Irland och Skottland. Flertalet av dessa puckellaxar härrör från ryska (sovjetiska) utsättningar runt Kolahalvön under perioden 1956 – 1998. Allt pekar på att arten har etablerat sig i området vid Norra ishavet och nu är inne i en snabb spridningsfas. Möjligheterna att utrota arten är förmodligen helt borta och det är osäkert om de ryska myndigheterna har önskan eller möjligheterna att vidta några åtgärder. Arten kan komma att påverka inhemska laxfiskar negativt och ur ett faunavårdsperspektiv vore det därför bra om puckellaxen kunde begränsas, både dess numerär och dess spridning. Puckellaxen har en strikt två-årscykel och i ursprungsområdena runt Stilla havet förekommer både udda- och jämna-års-bestånd. Eftersom det är udda-års-bestånden som lyckats bäst i nordvästra Ryssland så kommer förmodligen färre puckellaxar att observeras 2018, men eventuellt kan det bli än fler under 2019, färre 2020, fler 2021, och så vidare