Reduction of algal vegetation in Helgeland coastal waters

Reduced densities of Laminaria have been reported from coastal waters in Sør-Trøndelag, Nord-Trøndelag and Nordland counties. A provisional study of algal vegetation and benthic fauna was made by diving west of Vega in Helgeland, Nordland county (position 65°41'N 11°43 'E), 17-19 October 1979. The study revealed a significant difference in sublittoral density of sea urchins between three locations selected for abundant, scattered and no Laminaria growth. Strongylocentrotus droebachiensis dominated over Echinus esculentus at all three locations. The lowest sea urchin density was found at the location with abundant Laminaria, and a high density of sea urchins at the location with no or scattered Laminaria. It is therefore presumed that grazing by increasing numbers of sea urchins is a major factor causing a reduction of Laminaria. The catfish (Anarhichas lupus) may be the most important predator on sea urchins in these waters, and the catfish is preyed upon by seals. It is therefore suggested that increasing local stocks of grey seals (Halichoerus grypus), may have influenced the catfish abundance, and thus allowed the sea urchins to increase with a subsequant detrimental effect on the vegetation of Laminaria

Monitoreringssystem for forskning og innovasjon innen helse og omsorg. Et forprosjekt for å undersøke mulighetene

I dette forprosjektet undersøkes mulighetene for å etablere et helhetlig monitoreringssystem som kan gi et løpende kunnskapsgrunnlag for prioritering av og satsing på forskning og innovasjon innen helse og omsorg. Dette kan skje ved at indikatorene for forskning og innovasjon knyttes til helseindikatorer.Norges forskningsrå

Sleep disturbances in an arctic population: The Tromsø Study

<p>Abstract</p> <p>Background</p> <p>Prevalence estimates for insomnia range from 10 to 50% in the adult general population. Sleep disturbances cause great impairment in quality of life, which might even rival or exceed the impairment in other chronic medical disorders. The economic implications and use of health-care services related to chronic insomnia represent a clinical concern as well as a pronounced public health problem. Hypnotics are frequently prescribed for insomnia, but alcohol and over-the-counter sleep aids seem to be more widely used by insomniacs than prescription medications. Despite the complex relationship between insomnia and physical and mental health factors, the condition appears to be underrecognized and undertreated by health care providers, probably due to the generally limited knowledge of the causes and natural development of insomnia.</p> <p>Methods/Design</p> <p>The Tromsø Study is an ongoing population-based cohort study with five previous health studies undertaken between 1974 and 2001. This protocol outlines a planned study within the sixth Tromsø Study (Tromsø VI), aiming at; 1) describing sleep patterns in a community-based sample representative of the general population of northern Norway, and 2) examining outcome variables of sleep disturbances against possible explanatory and confounding variables, both within a cross-sectional approach, as well as retrospectively in a longitudinal study – exploring sleep patterns in subjects who have attended two or more of the previous Tromsø studies between 1974 and 2009. First, we plan to perform a simple screening in order to identify those participants with probable sleep disturbances, and secondly to investigate these sleep disturbances further, using an extensive sleep-questionnaire. We will also collect biological explanatory variables, i.e. blood samples, weight, height and blood pressure. We plan to merge data on an individual level from the Tromsø VI Study with data from the Norwegian Prescription Database (NorPD), which is a national registry including data for all prescription drugs issued at Norwegian pharmacies. Participants with sleep disturbances will be compared with pair-matched controls without sleep disturbances.</p> <p>Discussion</p> <p>Despite ongoing research, many challenges remain in the characterization of sleep disturbances and its correlates. Future mapping of the biological dimensions, natural history, as well as the behavioral and drug-related aspects of sleep disturbances in a representative population samples is clearly needed.</p

Reduksjon av tareskogen på Helgelandskysten

Reduced densities of Laminaria have been reported from coastal waters in Sør-Trøndelag, Nord-Trøndelag and Nordland counties. A provisional study of algal vegetation and benthic fauna was made by diving west of Vega in Helgeland, Nordland county (position 65°41'N 11°43 'E), 17-19 October 1979. The study revealed a significant difference in sublittoral density of sea urchins between three locations selected for abundant, scattered and no Laminaria growth. Strongylocentrotus droebachiensis dominated over Echinus esculentus at all three locations. The lowest sea urchin density was found at the location with abundant Laminaria, and a high density of sea urchins at the location with no or scattered Laminaria. It is therefore presumed that grazing by increasing numbers of sea urchins is a major factor causing a reduction of Laminaria. The catfish (Anarhichas lupus) may be the most important predator on sea urchins in these waters, and the catfish is preyed upon by seals. It is therefore suggested that increasing local stocks of grey seals (Halichoerus grypus), may have influenced the catfish abundance, and thus allowed the sea urchins to increase with a subsequant detrimental effect on the vegetation of Laminaria

Dynamic Identification and Modelling of a Pantograph

The main objective of this thesis is to measure and determine the dynamic properties of a measurement pantograph, and then create a numerical model with the same properties. The purpose of the model is to give a better representation of the actual behavior of the pantograph compared to the previously used lumped mass models. The thesis presents the process from very simple operation of the pantograph and contact force measurements, to more advanced studies of the attachment of the accelerometers and the development of test setups and procedures to measure the dynamic properties. The measurements done on the dynamic properties are then analyzed using scripts in MATLAB and the modal analysis software ARTeMIS. Using the results from the dynamic analysis, a numerical 3D model is created in Abaqus CAE with the same dynamic behavior as the pantograph in the lab

On the brink of the Arctic: Unusual intertidal sub-Arctic kelp associations in the Porsangerfjord, North Norway

<div><p></p><p>The kelps <i>Laminaria digitata</i> and <i>Saccharina latissima</i> are typically sub-littoral species. It is therefore surprising to find large intertidal kelp beds dominated by these two species in the inner Porsangerfjord, North Norway. The areas of the nine intertidal kelp beds ranged from 0.01 to 3 km² and covered a total area of 8.3 km². Both species had a prostrate growth form with short stipes, usually less than 10 cm long, independent of the length of the lamina. The laminae of <i>L. digitata</i> and <i>S. latissima</i> measured 77.0 ± 35.2 cm and 99.4 ± 41.0 cm (mean ± 1 SD), respectively. The associations occurred in sheltered areas with a muddy bottom on wide, flat areas of moraine. The areas are completely drained at low tide. The holdfasts were attached to small pebbles sunk in the mud. The mean biomass density of the two dominant kelp species was 4.1 ± 1.8 kg m⁻². The mean biomass of all the algal species in the association was 6.1 ± 2.2 kg m⁻². A total of 32 species were identified in the association, of which 16 species were annuals and 16 were perennials. All the species found in the kelp associations are also found in the Arctic. The prostrate growth form of <i>L. digitata</i> and <i>S. latissima</i>, the topography and substrate of the intertidal zone, low summer temperatures, low desiccation and protective sea ice during winter are possible factors contributing to the formation of these unusual intertidal kelp associations.</p></div

Design Sensitivities By the Adjoint Variable Method in Nonlinear Structural Dynamics

This paper describes a new algorithm to calculate gradients of system responses with respect to design changes. The algorithm uses the adjoint variable method, and is compared with an algorithm employing the direct differentiation method. Both algorithms are closely related to the response calculation by the Newmark and Newton-Raphson methods in nonlinear mechanical and structural systems. In linear dynamics the method yielding the smallest number of sensitivity equations is preferred. In nonlinear structural dynamics the direct method is better included in the response calculation, hence the adjoint method can be less efficient for large structural systems even with a smaller number of sensitivity equations. 1 Introduction In a sensitivity analysis the gradients of response functionals with respect to the design variables are calculated. These gradients, sometimes denoted design sensitivities, are used to evaluate the effects of design variations, and are used by gradient-based mathe..