Analysing the mechanical performance and growth adaptation of Norway spruce using a non-linear finite-element model and experimental data

Thirteen Norway spruce [Picea abies (L.) Karst.] trees of different size, age, and social status, and grown under varying conditions, were investigated to see how they react to complex natural static loading under summer and winter conditions, and how they have adapted their growth to such combinations of load and tree state. For this purpose a non-linear finite-element model and an extensive experimental data set were used, as well as a new formulation describing the degree to which the exploitation of the bending stress capacity is uniform. The three main findings were: material and geometric non-linearities play important roles when analysing tree deflections and critical loads; the strengths of the stem and the anchorage mutually adapt to the local wind acting on the tree crown in the forest canopy; and the radial stem growth follows a mechanically high-performance path because it adapts to prevailing as well as acute seasonal combinations of the tree state (e.g. frozen or unfrozen stem and anchorage) and load (e.g. wind and vertical and lateral snow pressure). Young trees appeared to adapt to such combinations in a more differentiated way than older trees. In conclusion, the mechanical performance of the Norway spruce studied was mostly very high, indicating that their overall growth had been clearly influenced by the external site- and tree-specific mechanical stres

Flodkräftans biologi och status i fyra sjöar på Ulvöarna

Flodkräftan har minskat i antal efter att kräftpesten införts via signalkräftor till svenska sjöar och vattendrag. Inplantering av signalkräftor har medfört svårigheter för flodkräftsbestånd att återhämta sig då signalkräftan bär kräftpesten, men inte själva påverkas i större utsträckning. Förutom sjukdomar påverkas flodkräftors populationsstorlek också av predation. Om man bortser från pesten är det svårt att fastställa orsaken till populationsminskningen i sjöarna då många faktorer är inblandade. Syftet med detta examensarbete är att genomföra en litteraturstudie och att fastställa förekomst av flodkräfta i fyra sjöar i Västernorrlands län. I litteraturdelen behandlas bla. flodkräftans sjukdomar, beteenden och provfiskemetoder. Fältundersökningar riktade mot flodkräftsinventering och nyttjande av fångst och återfångst metoder förväntades ge bakgrundsfakta för att skapa en åtgärdsplan så att flodkräftans framtid i de undersökta sjöarna på Ulvön kan säkerställas. Ulvöarna ligger ca 2 mil sydost om Örnsköldsvik. Provfiskeresultaten visade att flodkräfta fanns i samtliga undersökta sjöar, och ingen signalkräfta påträffades. Två kräftbestånd var undermåliga och deras fortlevnad på kort sikt var starkt hotad. Den högsta beståndstäthet som påträffades var ca 0,3 kräftor/m2 vilket är under rapporterade litteraturvärden. Riktade åtgärder som t.ex. utsättning av skydd åt kräftorna kan höja produktionen och säkra framtida bestånd i samtliga provfiskade vatten

Influence of harvester size and feeding principle on feeding damage depth at harvest of spruce timber

Vid val av skördare för gallring eller slutavverkning väljs ofta maskiner som finns i närområdet och med högst produktivitet. Detta kan medföra att maskiner väljs trots att de inte är bäst anpassade för den aktuella åtgärden. Risken med detta är en hård behandling av träden under avverkningen som ger onödigt stora stamskador. Arbetet handlar om hur man med aktiva val kan minska dessa skador. De faktorer som analyserades var; typ av matarhjul, storlek på maskin och hur barktjockleken inverkar på matningsskadedjup. Datamaterialet samlades in sommaren 2012 åt Vida AB i Västra Götaland och Småland. Vedprover togs på klentimmerstockar (<18 cm i toppdiameter) i gallring och slutavverkning. Resultaten från analyserna visade att vid val av matarhjul med dubb så kan man förvänta sig att få djupare skador (5,13 mm i genomsnitt) än vid användning av ribb (4,43 mm), en anledning att fortfarande välja dubb kan vara en något högre produktivitet. Gränsen för kvalitetsnedsättande skada vid inmätning är 6,9mm. Maskinstorleken spelar in i form av att om man använder en stor maskin (>16 ton) så kan man förvänta sig djupare matarhjulsskador (5,28 mm) än med en liten (<16 ton) maskin (3,95 mm) på klenare stammar. Med ökad barktjocklek minskar risken för matarhjulsskador. Resultaten visar att det finns anledning att tänka efter en extra gång när man väljer maskin till gallring eller slutavverkning i bestånd där man förväntas ta ut klentimmer för sågning. Om man väljer rätt maskin och matarhjul så kan risken för matarhjulsskador minska.When choosing harvester for thinning or clear cutting, the choice is often based on what machines that are available in the area and the productivity of the machine. Basing the choice only on these factors can result in using a machine that is not fitted for the activity. The result can be a very rough treatment of the logs that causes unnecessary damages. This report quantifies how different factors affect the risk of possible damages. The analyzed factors are; feeder wheels (ribs or spikes), machine size and how bark thickness influence on stud damages. The dataset was collected during the summer of 2012 for the company Vida AB in the regions of Västra Götaland and Småland, Sweden. The measurements were made on small diameter logs (< 18 cm in top). The result indicates that spike-wheels causes deeper damage (5,13 mm in average) than rib-wheels (4,43 mm). A reason to still use spikes might be a higher productivity. The limit for quality suppressant damage at the mill is 6,9mm. The machine size is important in the way that a bigger machine causes deeper damages (5,28 mm) than smaller machines (3,95 mm) on small diameter logs. The bark thickness has a significant effect on the depth of the feed-wheel damages. It is important to be careful when choosing harvester in areas with small diameter logs. The conclusion is that if you choose the correct machine and feed roller, the risk for feed-wheel damages will be reduced

Revisorns roll och uppgift i en föränderlig social kontext

Uppsatsens syfte är att belysa hur revisorns roll och uppgift kan påverkas av förändringar i den sociala kontexten, och vad detta kan få för konsekvenser för revisorsbranschen. Uppsatsen utgår från en fenomenologisk vetenskapsansats, då det är ett fenomen som studeras. Syftet med studien är att bidra med kunskap som inte var känd förut, och därav har ett kvalitativt metodperspektiv valts. Undersökningsansatsen är huvudsakligen induktiv, men även abduktiva inslag förekommer i studien. Referensramen omfattar en genomgång av relevant litteratur för problemområdet. Teorier om social ordning, oberoende och förtroende studeras. Det empiriska materialet utgörs av en fallstudie baserad på nio personliga intervjuer med revisorer. Studien har resulterat i ett praktiskt och ett teoretiskt bidrag. Det praktiska bidraget består av att fem teorier formuleras, som sedan ska kunna testas genom hypotesprövning. Hypotesprövning faller emellertid utanför ramarna för denna uppsats. Det teoretiska bidraget utgörs av en modell som visar hur revisorns roll och uppgift påverkas av och interagerar med den sociala ordningen och revisorns trovärdighet. Denna interaktion och utveckling sker i ett sammanhang som utgör revisorns sociala kontext

Association study between autistic-like traits and polymorphisms in the autism candidate regions RELN, CNTNAP2, SHANK3, and CDH9/10

The Swedish Research CouncilThe Swedish Council for Working Life and Social ResearchThe Petrus and Augusta Hedlund FoundationÅke Wiberg foundationÅhlens FoundationWilhelm and Martina Lundgren FoundationThe Sahlgrenska AcademyPublishe

Association between ASMT and autistic-like traits in children from a Swedish nationwide cohort

Persons with autism spectrum disorders (ASDs) often display low levels of melatonin, and it has been suggested that this decrease may be due to low activity of the acetylserotonin O-methyltransferase (ASMT), the last enzyme in the melatonin synthesis pathway. Moreover, genetic variants in ASMT have been associated with autism, as well as with low ASMT activity and melatonin levels, suggesting that the low ASMT activity observed in autism may partly be due to variation within the ASMT gene. In this study, we present a symptom-based approach to investigate possible associations between ASMT and autistic-like traits (ALTs) in the general population. To this end, continuous measures of ALTs were assessed in a nationally representative twin cohort (n=1771) from Sweden and six Single Nucleotide Polymorphisms (SNP) and a duplication of exon 2 to 8 in ASMT were genotyped. Our results show a nominally significant association, in girls, between one SNP (rs5949028) in the last intron of ASMT and social interaction impairments. No significant association, however, was observed with traits related to language impairment or restricted and repetitive behavior. In conclusion, our results support the possible involvement of the ASMT gene in ASDs and our finding that only one of three traits shows association suggests that genetic research may benefit from taking a symptom-specific approach to identify genes involved in autism psychopathology.VetenskapsrådetAccepte

Further investigations of the relation between polymorphisms in sex steroid related genes and autistic-like traits

Autism spectrum disorders (ASDs) are more prevalent in boys than in girls, indicating that high levels of testosterone during early development may be a risk factor. Evidence for this hypothesis comes from studies showing associations between fetal testosterone levels, as well as indirect measures of prenatal androgenization, and ASDs and autistic-like traits (ALTs). In a recent study we reported associations between ALTs and single nucleotide polymorphisms (SNPs) in the genes encoding estrogen receptor 1 (ESR1), steroid-5-alpha-reductase, type 2 (SRD5A2) and sex hormone-binding globulin (SHBG) in a subset (n=1771) from the Child and Adolescent Twin Study in Sweden (CATSS). The aim of the present study was to try to replicate these findings in an additional, larger, sample of individuals from the CATSS (n=10 654), as well as to analyze additional SNPs of functional importance in SHBG and SRD5A2. No associations between the previously associated SNPs in the genes ESR1 and SRD5A2 and ALTs could be seen in the large replication sample. Still, our results show that two non-linked SNPs (rs6259 and rs9901675) at the SHBG gene locus might be of importance for language impairment problems in boys. The results of the present study do not point towards a major role for the investigated SNPs in the genes ESR1 and SRD5A2 in ALTs, but a possible influence of genetic variation in SHBG, especially for language impairment problems in boys, cannot be ruled out.NoneAccepte

Long-term effects of no-take zones in Swedish waters

Marine protected areas (MPAs) are increasingly established worldwide to protect and restore degraded ecosystems. However, the level of protection varies among MPAs and has been found to affect the outcome of the closure. In no-take zones (NTZs), no fishing or extraction of marine organisms is allowed. The EU Commission recently committed to protect 30% of European waters by 2030 through the updated Biodiversity Strategy. Importantly, one third of these 30% should be of strict protection. Exactly what is meant by strict protection is not entirely clear, but fishing would likely have to be fully or largely prohibited in these areas. This new target for strictly protected areas highlights the need to evaluate the ecological effects of NTZs, particularly in regions like northern Europe where such evaluations are scarce. The Swedish NTZs made up approximately two thirds of the total areal extent of NTZs in Europe a decade ago. Given that these areas have been closed for at least 10 years and can provide insights into long-term effects of NTZs on fish and ecosystems, they are of broad interest in light of the new 10% strict protection by 2030 commitment by EU member states.In total, eight NTZs in Swedish coastal and offshore waters were evaluated in the current report, with respect to primarily the responses of focal species for the conservation measure, but in some of the areas also ecosystem responses. Five of the NTZs were established in 2009-2011, as part of a government commission, while the other three had been established earlier. The results of the evaluations are presented in a synthesis and also in separate, more detailed chapters for each of the eight NTZs. Overall, the results suggest that NTZs can increase abundances and biomasses of fish and decapod crustaceans, given that the closed areas are strategically placed and of an appropriate size in relation to the life cycle of the focal species. A meta-regression of the effects on focal species of the NTZs showed that CPUE was on average 2.6 times higher after three years of protection, and 3.8 times higher than in the fished reference areas after six years of protection. The proportion of old and large individuals increased in most NTZs, and thereby also the reproductive potential of populations. The increase in abundance of large predatory fish also likely contributed to restoring ecosystem functions, such as top-down control. These effects appeared after a 5-year period and in many cases remained and continued to increase in the longer term (>10 years). In the two areas where cod was the focal species of the NTZs, positive responses were weak, likely as an effect of long-term past, and in the Kattegat still present, recruitment overfishing. In the Baltic Sea, predation by grey seal and cormorant was in some cases so high that it likely counteracted the positive effects of removing fisheries and led to stock declines in the NTZs. In most cases, the introduction of the NTZs has likely decreased the total fishing effort rather than displacing it to adjacent areas. In the Kattegat NTZ, however, the purpose was explicitly to displace an unselective coastal mixed bottom-trawl fishery targeting Norway lobster and flatfish to areas where the bycatches of mature cod were smaller. In two areas that were reopened to fishing after 5 years, the positive effects of the NTZs on fish stocks eroded quickly to pre-closure levels despite that the areas remained closed during the spawning period, highlighting that permanent closures may be necessary to maintain positive effects.We conclude from the Swedish case studies that NTZs may well function as a complement to other fisheries management measures, such as catch, effort and gear regulations. The experiences from the current evaluation show that NTZs can be an important tool for fisheries management especially for local coastal fish populations and areas with mixed fisheries, as well as in cases where there is a need to counteract adverse ecosystem effects of fishing. NTZs are also needed as reference for marine environmental management, and for understanding the effects of fishing on fish populations and other ecosystem components in relation to other pressures. MPAs where the protection of both fish and their habitats is combined may be an important instrument for ecosystembased management, where the recovery of large predatory fish may lead to a restoration of important ecosystem functions and contribute to improving decayed habitats.With the new Biodiversity Strategy, EUs level of ambition for marine conservation increases significantly, with the goal of 30% of coastal and marine waters protected by 2030, and, importantly, one third of these areas being strictly protected. From a conservation perspective, rare, sensitive and/or charismatic species or habitats are often in focus when designating MPAs, and displacement of fisheries is then considered an unwanted side effect. However, if the establishment of strictly protected areas also aims to rebuild fish stocks, these MPAs should be placed in heavily fished areas and designed to protect depleted populations by accounting for their home ranges to generate positive outcomes. Thus, extensive displacement of fisheries is required to reach benefits for depleted populations, and need to be accounted for e.g. by specific regulations outside the strictly protected areas. These new extensive EU goals for MPA establishment pose a challenge for management, but at the same time offer an opportunity to bridge the current gap between conservation and fisheries management

Antisocial behavior and polymorphisms in the oxytocin receptor gene : findings in two independent samples

Importance: The quantitative genetic contribution to antisocial behavior is well established, but few, if any, genetic variants are established as risk factors. Emerging evidence suggests that the neuropeptide oxytocin may modulate interpersonal aggression. Objective: To investigate whether single nucleotide polymorphisms in the oxytocin receptor gene are associated with the expression of antisocial behavior. Design, setting, and participants: A discovery sample, including both sexes, was drawn from the Child and Adolescent Twin Study of Sweden (CATSS; n=2,372), and a sample from the Twin Study of Child and Adolescent Development (TCHAD; n=1,232) was used for replication. The participants were assessed for antisocial behavior, measured as continuous traits. Eight single nucleotide polymorphisms in the oxytocin receptor gene, selected on previous associations with social and antisocial behavior, were then genotyped in the participants of CATSS. Significant polymorphisms were subsequently genotyped in TCHAD for replication. Main outcomes and measures: Participants completed self-assessment questionnaires – Life History of Aggression (available only in CATSS), and Self-Reported Delinquency (available in both samples) – designed to capture antisocial behavior. Results: In the discovery sample, the rs7632287 AA genotype was associated with higher frequency of antisocial behavior in boys, and this was then replicated in the second sample. In particular, overt aggression (directly targeting another individual) was strongly associated with this genotype in boys (p=6.2x10-7 in the discovery sample). Meta-analysis of the results for antisocial behavior from both samples yielded p=2.5x10-5. Furthermore, an association between rs4564970 and Life History of Aggression (p=0.00013) survived correction in the discovery sample, but there was no association with the Self-Reported Delinquency in the replication sample. Conclusions and relevance: We conclude that the rs7632287 and rs4564970 polymorphisms in the oxytocin receptor gene may independently influence antisocial behavior in adolescent boys. Further replication of our results will be crucial to understanding how aberrant social behavior arises, and supports the oxytocin receptor as one potential target in the treatment of aggressive antisocial behavior.Swedish Research CouncilSwedish Research Council for Working Life and Social ResearchThe Society of Swedish Literature in FinlandSöderström-Königska FoundationAccepte

Dissemination of Spotted Fever Rickettsia Agents in Europe by Migrating Birds

Migratory birds are known to play a role as long-distance vectors for many microorganisms. To investigate whether this is true of rickettsial agents as well, we characterized tick infestation and gathered ticks from 13,260 migratory passerine birds in Sweden. A total of 1127 Ixodes spp. ticks were removed from these birds and the extracted DNA from 957 of them was available for analyses. The DNA was assayed for detection of Rickettsia spp. using real-time PCR, followed by DNA sequencing for species identification. Rickettsia spp. organisms were detected in 108 (11.3%) of the ticks. Rickettsia helvetica, a spotted fever rickettsia associated with human infections, was predominant among the PCR-positive samples. In 9 (0.8%) of the ticks, the partial sequences of 17kDa and ompB genes showed the greatest similarity to Rickettsia monacensis, an etiologic agent of Mediterranean spotted fever-like illness, previously described in southern Europe as well as to the Rickettsia sp.IrITA3 strain. For 15 (1.4%) of the ticks, the 17kDa, ompB, gltA and ompA genes showed the greatest similarity to Rickettsia sp. strain Davousti, Rickettsia japonica and Rickettsia heilongjiangensis, all closely phylogenetically related, the former previously found in Amblyomma tholloni ticks in Africa and previously not detected in Ixodes spp. ticks. The infestation prevalence of ticks infected with rickettsial organisms was four times higher among ground foraging birds than among other bird species, but the two groups were equally competent in transmitting Rickettsia species. The birds did not seem to serve as reservoir hosts for Rickettsia spp., but in one case it seems likely that the bird was rickettsiemic and that the ticks had acquired the bacteria from the blood of the bird. In conclusion, migratory passerine birds host epidemiologically important vector ticks and Rickettsia species and contribute to the geographic distribution of spotted fever rickettsial agents and their diseases