Summary 1 Analysis of the dynamics rust disease caused by Uromyces valerianae in 30 discrete populations Valeriana salina occurring on an archipelago small islands Gulf Bothnia, central Sweden, showed strong temporal and spatial effects. 2 Over a 13‐year period, population pathogen varied across metapopulation, with incidence (presence/absence), prevalence severity all showing year effects, indicative heterogeneity among years host suitability conditions for pathogen. While some individual...

Enhancement of tumor cell growth and invasiveness by transforming factor-β (TGF-β) requires constitutive activation the ras/MAPK pathway. Here we have investigated how MEK epidermal factor (EGF) influences response fully differentiated growth-arrested pig thyroid epithelial cells in primary culture to TGF-β1. The tightness was maintained after single stimulation with EGF or TGF-β1 (both 10 ng/ml) for 48 hours. In contrast, co-stimulation abolished transepithelial resistance increased...

Associational resistance occurs when herbivore damage to a focal plant is reduced by the presence of other species. Neighboring plants can reduce (1) their effects on predator community, (2) reducing ability herbivores find host plants, and (3) time remain plants. We examined how aromatic low shrub Myrica gale predatory lady beetles affected reproductive output in population perennial herb Lythrum salicaria northern Sweden. An observational study showed that L. growing thickets were less...

To improve our knowledge regarding plant responses to herbivory we subjected juvenile birches (Betula pubescens) different types of simulated herbivory, i.e., removal the top (1 cm) main stem or defoliaiton (including top), and levels intraspecific competition (i.e., three stand densities). Treatments were also repeated during following year. Birch these treatments measured as changes in height dry mass. Defoliated plants showed reduced growth irrespective level competition. Topped...

The aim of this study was to detect vegetation change and examine trophic interactions in a Sphagnum-dominated mire response raised temperature nitrogen (N) addition. A long-term global-change experiment established 1995, with monthly additions N (30 kg x ha(-1) yr(-1)) sulfur (20 during the period. Mean air by 3.6 degrees C warming chambers. Vegetation responses were negligible for all treatments first four years, no effect seen course experiment. However, after eight years continuous...

1 A set of metapopulation models representing non-exclusive hypotheses for the persistence a parasite in time were used to examine spatial patterns and processes Triphragmium ulmariae–Filipendula ulmaria parasite–host interaction from Skeppsvik Archipelago, northern Sweden, using ecological data an 11-year study. 2 Models fitted maximum likelihood subsequently ranked parsimony criteria derived information theory. 3 Over intermediate time-scales (10–100 years), is determined by core-satellite...

Summary Ecosystem recovery after decreased input of nitrogen was examined in two different fertilization experiments where the had been terminated for 9 and 47 years, respectively. The species composition understorey vegetation showed no signs years terminated. Increased sporocarp production mycorrhizal fungi seen on formerly fertilized plots compared with still receiving N, but large differences to control plots. In second experiment, termination fertilization, N favoured bryophytes such as...

Summary Experimental additions of N to an old‐growth boreal forest resulted in elevated levels free amino acids leaves the dominant dwarf‐shrub Vaccinium myrtillus and increased attack from a parasitic fungus, Valdensia heterodoxa . Glutamine leaf surface V. disease incidence by average almost three times compared controls suggested causal connection between acid availability fungal infection. Increased abundance grass Deschampsia flexuosa followed addition but infection which causes...

7 clinically stable, “osseointegrated”, titanium implants, inserted in human jaws for l–16 years, were retrieved morphological analysis of the bone‐titanium interface, using 3 different preparation techniques. The interface varied as judged from light microscopy ground sections. threads implants well filled 79–95% with dense lamellar bone quantified morphometry. A large fraction implant surface (56–85%) appeared to be direct contact mineralized bone. In general, non‐boric areas consisted...

1. We report the short‐term effects of simulated nitrogen (N) deposition on understorey a boreal forest in northern Sweden. Doses 15 N double‐labelled NH 4 NO 3 (0·5, 12·5, 25·0 and 50·0 kg ha –1 ) were applied to 1 m 2 plots summer 1995 plants harvested following autumn. 2. No significant treatment found either above‐ or below‐ground biomass which was distributed as follows: ericaceous shrub Vaccinium myrtillus contributed 76%, grass Deschampsia flexuosa 4%, bryophytes Dicranum majus...

The objective was to examine injury rates and associated risk factors in a representative sample of climbers. A random ( n =606) the Swedish Climbing Association members sent postal survey, with an effective response rate 63%. Self‐reported data regarding climbing history, safety practices retrospective accounts events (recall period 1.5 years) were obtained. Descriptive statistical methods used calculate incidences, two‐step method including zero‐inflated Poisson's regression analysis...