Variability of nutrient limitation in the Archipelago Sea, SW Finland

Eutrophication is the most acute environmental problem in the Archipelago Sea, SW Finland. When analysing the factors behind this escalating eutrophication the determination of limiting nutrient at a given time is essential. Besides experimentations, nutrient limitation of plankton has been extensively studied by direct chemical analyses. We used the latter approach in this work. Nutrient limitation was studied by calculating different nutrient ratios - total nitrogen:phosphorus, inorganic nitrogen:phosphorus, and nutrient balance ratio. Results showed that phosphorus usually limited primary production only near the coast line. In the middle zone of the Archipelago Sea the limiting factor varied temporally. Outer in the open sea nitrogen limited primary production during most of the year. Phosphorus limited phytoplankton growth especially in spring and in summer and nitrogen in late summer and in autumn. Our results suggested that nitrogen is an important limiting nutrient in the Archipelago Sea. In recent years when the eutrophication has proceeded there has been a shift from.production limitation by both nutrients to limitation by nitrogen alone. But if we want to define and characterize the nutrient limitation of the entire ecosystem of the Archipelago Sea, budgets have to be calculated for both N and P and internal recycling must be taken into account as well as external supply of nutrients and loss processes.</p

Multiple psychological factors predict pain and disability among community-dwelling knee osteoarthritis patients : a five-year prospective study

Objective: To identify predictors of long-term pain and disability in knee osteoarthritis. Design: A longitudinal cohort study of five years. Setting: Primary care providers. Subjects: In all, 108 patients (mean age = 63.6 years, standard deviation (SD) = 7.2 years) with knee pain (> 40 mm on a 100 mm visual analogue scale in the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index pain scale) and radiographic grading (Kellgren-Lawrence: 2-4) of knee osteoarthritis who participated in a randomized controlled trial. Main measures: Disease-specific pain and functioning were assessed using the corresponding WOMAC subscales. Generic functioning was assessed by the RAND-36 subscales for function and physical and mental component summary scores. Possible baseline predictors for these outcomes were (1) demographic and disease-related variables and (2) psychological variables of mood (anxiety, depression), pain-related cognitions (pain self-efficacy, pain catastrophizing, kinesiophobia), and positive resource factors (life satisfaction, sense of coherence). Results: Multivariate linear mixed model analyses revealed that minimal anxiety at baseline predicted significantly better results for pain (WOMAC, P = 0.019) and function (WOMAC, P = 0.001, RAND-36 function P = 0.001). High pain self-efficacy predicted significantly better scores in RAND-36 function (P = 0.006), physical (P = 0.004) and mental (P = 0.001) component summaries. Pain catastrophizing predicted higher pain (P = 0.015), whereas fear of movement predicted poorer functioning in RAND-36 physical (P = 0.016) and mental (P = 0.009) component summaries. Those satisfied with life reported higher scores in RAND-36 function (P = 0.002) and mental component summary (P = 0.041). A low number of comorbidities predicted significantly better results in pain (WOMAC P = 0.019) and function (WOMAC P = 0.033, RAND-36 P = 0.009). Conclusion: Anxiety, pain-related cognitions, and psychological resources predict symptoms in knee osteoarthritis in the long term.Peer reviewe

A New Application of the Gursey and Radicati Mass Formula

We study the spin- and flavour- dependent SU(6) violations in the baryon spectrum by means of a G\"ursey Radicati mass formula. The average energy of each SU(6)-multiplet is described using the SU(6) invariant interaction given by a hypercentral potential containing a linear and a hypercoulomb term. We show that the non strange and strange baryon masses are in general fairly well reproduced and moreover that the G\"ursey Radicati formula holds in a satisfactory way also for the excited states up to 2 GeV. The coefficients of the G\"ursey Radicati SU(6) breaking part obtained by the fit of the three-quark spectrum can be used to evaluate in first approximation the splitting within multiplets also for exotic baryon systems.Comment: 9 pages, 2 figures, 2 table, submitted to Eur. Phys. J.

Meson exchange and nucleon polarizabilities in the quark model

Modifications to the nucleon electric polarizability induced by pion and sigma exchange in the q-q potentials are studied by means of sum rule techniques within a non-relativistic quark model. Contributions from meson exchange interactions are found to be small and in general reduce the quark core polarizability for a number of hybrid and one-boson-exchange q-q models. These results can be explained by the constraints that the baryonic spectrum impose on the short range behavior of the mesonic interactions.Comment: 11 pages, 1 figure added, expanded discussio

The π−\pi-Gluon Exchange Interaction Between Constituent Quarks

The interaction mediated by irreducible pion and gluon exchange between constituent quarks is calculated and shown to have a strong tensor component, which tends to cancel the pion exchange tensor interaction between quarks. Its spin-spin component is somewhat weaker than the pion exchange spin-spin interaction, while its central and spin-orbit components are small in comparison to the corresponding single gluon exchange interactions. The combination of the $\pi-$gluon exchange interaction with the single pion exchange interaction and a weak gluon exchange interaction between constituent quarks has the qualitative features required for understanding the hyperfine splittings of the spectra of the nucleon and the $\Delta$ resonances.Comment: LaTeX, 17 pages, 5 Postscript figure

Sustainability of cellulose dissolution and regeneration in 1,5-diazabicyclo[4.3.0]non-5-enium acetate : a batch simulation of the IONCELL-F process

The recyclability of 1,5-diazabicyclo[4.3.0] non-5-enium acetate ([DBNH][OAc]), as a direct dissolution solvent for cellulose, was evaluated during laboratory scale recycling trials. The main objective was to simulate the conditions of a spinning bath from a Lyocell-type air-gap spinning process, called the IONCELL-F process. The saline solution was then concentrated, recycled and reused as many times as possible before cellulose dissolution was no longer possible. The chemical compositions of the ionic liquid and pulp were recorded throughout the experiments. The results of the experiments showed that [DBNH][OAc] can be recycled from aqueous media with an average recovery rate of 95.6 wt% using basic laboratory equipment, without any further process intensification or optimisation. The recycling of the ionic liquid did not change the chemical composition or degree of polymerisation of the recovered pulp but the colour of the regenerated pulps gradually darkened as the recycling times increased. The ionic liquid was found to hydrolyse 6.0-13.6 mol% per cycle, under these conditions. The build-up of the hydrolysis product, 3-( aminopropyl)-2-pyrrolidonium acetate, killed the dissolution feature at between 30.6-45.6 wt% hydrolysis product. The enzymatic digestibility of the regenerated pulp samples was studied with both a monocomponent endoglucanase and a cellulase mixture. The amount of residual [DBNH][OAc] in the regenerated pulps was determined, by both NMR and capillary electrophoresis. Although hydrolysis of the ionic liquid occurs, this study clearly shows potential for industrial application, with appropriate process equipment and recycling conditions.Peer reviewe

Decline after immobilisation and recovery after remobilisation of synovial fluid IL1, TIMP, and chondroitin sulphate levels in young beagle dogs

OBJECTIVE: To monitor the concentration of markers of cartilage and synovium metabolism in the knee (stifle) joint synovial fluid of young beagles subjected to immobilisation and subsequent remobilisation.METHODS: The right hind limb of 17 dogs was immobilised in flexion for 11 weeks. Simultaneously, the contralateral left knee was exposed to increased weight bearing. The remobilisation period lasted 50 weeks. Litter mates served as controls. The concentration in joint lavage fluid of interleukin 1 (IL1) was measured by immunoassay, the activity of phospholipase A2 (PLA2) was determined by an extraction method, chondroitin sulphate (CS) concentration by precipitation with Alcian blue, hyaluronan (HA) by an ELISA-like assay using biotinylated HA-binding complexes, matrix metalloproteinase 3 (MMP-3), and tissue inhibitor of metalloproteinases 1 (TIMP-1) by sandwich ELISA, and synovitis was scored by light microscopy.RESULTS: Synovitis or effusion was absent in all experimental and control groups. Immobilisation decreased the joint lavage fluid levels of IL1 (p<0.05), TIMP (p< 0.05), and the concentration of CS down to 38 (p<0.05) in comparison with untreated litter mates with normal weight bearing. Immobilisation did not affect the activity of PLA2, or the concentration of MMP-3 or HA in synovial fluid. Joint remobilisation restored the decreased concentrations of markers to control levels. Increased weight bearing did not change the concentrations of markers in comparison with the control joints with normal weight bearing.CONCLUSIONS: 11 weeks joint immobilisation decreased the concentration of markers of cartilage and synovium metabolism in the synovial fluid, and remobilisation restored the concentrations to control levels. The changes in joint metabolism induced by immobilisation, as reflected by the markers, are thus different from those found in osteoarthritis, where increased levels of these markers are associated with enhanced degradation and synthesis. These findings suggest that the change induced in joint metabolism by immobilisation is reversible in its early stages