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Objective: The insufficient diagnostic accuracy for differentiation between benign and malignant adrenocortical disease and lack of sensitive markers reflecting tumor load emphasize the need for novel biomarkers for diagnosis and follow-up of adrenocortical carcinoma (ACC)., Design: Since the inhibin α-subunit is expressed within the adrenal cortex, the role of serum inhibin pro-αC as a tumor marker for ACC was studied in patients., Methods: Regulation of adrenal pro-αC secretion was investigated by adrenocortical function tests. Serum inhibin pro-αC levels were measured in controls (n=181) and patients with adrenocortical hyperplasia (n=45), adrenocortical adenoma (ADA, n=32), ACC (n=32), or non-cortical tumors (n=12). Steroid hormone, ACTH, and inhibin A and B levels were also estimated in patient subsets., Results: Serum inhibin pro-αC levels increased by 16% after stimulation with ACTH (P=0.043). ACC patients had higher serum inhibin pro-αC levels than controls (medians 733 vs 307 ng/l, P<0.0001) and patients with adrenocortical hyperplasia, ADA, or non-adrenocortical adrenal tumors (148, 208, and 131 ng/l, respectively, P=0.0003). Inhibin pro-αC measurement in ACC patients had a sensitivity of 59% and specificity of 84% for differentiation from ADA patients. Receiver operating characteristic analysis displayed areas under the curve of 0.87 for ACC vs controls and 0.81 for ACC vs ADA (P<0.0001). Surgery or mitotane therapy was followed by a decrease of inhibin pro-αC levels in 10/10 ACC patients tested during follow-up (P=0.0065)., Conclusions: Inhibin pro-αC is produced by the adrenal gland. Differentiation between ADA and ACC by serum inhibin pro-αC is limited, but its levels may constitute a novel tumor marker for ACC.

Our understanding of positive and negative plant interactions is primarily based on vascular plants, as is the prediction that facilitative effects dominate in harsh environments. It remains unclear whether this understanding is also applicable to moss-vascular plant interactions, which are likely to be influential in low-temperature environments with extensive moss ground cover such as boreal forest and arctic tundra. In a field experiment in high-arctic tundra, we investigated positive and negative impacts of the moss layer on vascular plants. Ramets of the shrub Salix polaris, herb Bistorta vivipara, grass Alopecurus borealis and rush Luzula confusa were transplanted into plots manipulated to contain bare soil, shallow moss (3 cm) and deep moss (6 cm) and harvested after three growing seasons. The moss layer had both positive and negative impacts upon vascular plant growth, the relative extent of which varied among vascular plant species. Deep moss cover reduced soil temperature and nitrogen availability, and this was reflected in reduced graminoid productivity. Shrub and herb biomass were greatest in shallow moss, where soil moisture also appeared to be highest. The relative importance of the mechanisms by which moss may influence vascular plants, through effects on soil temperature, moisture and nitrogen availability, was investigated in a phytotron growth experiment. Soil temperature, and not nutrient availability, determined Alopecurus growth, whereas Salix only responded to increased temperature if soil nitrogen was also increased. We propose a conceptual model showing the relative importance of positive and negative influences of the moss mat on vascular plants along a gradient of moss depth and illustrate species-specific outcomes. Our findings suggest that, through their strong influence on the soil environment, mat-forming mosses structure the composition of vascular plant communities. Thus, for plant interaction theory to be widely applicable to extreme environments such as the Arctic, growth forms other than vascular plants should be considered.

The potential of alpine moss-sedge heath to recover from elevated nitrogen (N) deposition was assessed by transplanting Racomitrium lanuginosum shoots and vegetation turfs between 10 elevated N deposition sites (8.2-32.9 kg ha(-1) yr(-1)) and a low N deposition site, Ben Wyvis (7.2 kg ha(-1) yr(-1)). After two years, tissue N of Racomitrium shoots transplanted from higher N sites to Ben Wyvis only partially equilibrated to reduced N deposition whereas reciprocal transplants almost matched the tissue N of indigenous moss. Unexpectedly, moss shoot growth was stimulated at higher N deposition sites. However, moss depth and biomass increased in turfs transplanted to Ben Wyvis, apparently due to slower shoot turnover (suggested to result partly from decreased tissue C:N slowing decomposition), whilst abundance of vascular species declined. Racomitrium heath has the potential to recover from the impacts of N deposition; however, this is constrained by the persistence of enhanced moss tissue N contents., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The carbon (C) sink strength of arctic tundra is under pressure from increasing populations of arctic breeding geese. In this study we examined how CO 2 and CH 4 fluxes, plant biomass and soil C responded to the removal of vertebrate herbivores in a high arctic wet moss meadow that has been intensively used by barnacle geese ( Branta leucopsis ) for ca. 20 years. We used 4 and 9 years old grazing exclosures to investigate the potential for recovery of ecosystem function during the growing season (July 2007). The results show greater above- and below-ground vascular plant biomass within the grazing exclosures with graminoid biomass being most responsive to the removal of herbivory whilst moss biomass remained unchanged. The changes in biomass switched the system from net emission to net uptake of CO 2 (0.47 and -0.77 μmol m -2  s -1 in grazed and exclosure plots, respectively) during the growing season and doubled the C storage in live biomass. In contrast, the treatment had no impact on the CH 4 fluxes, the total litter C pool or the soil C concentration. The rapid recovery of the above ground biomass and CO 2 fluxes demonstrates the plasticity of this high arctic ecosystem in terms of response to changing herbivore pressure.

Background: "The enigma of soil animal species diversity" was the title of a popular article by J. M. Anderson published in 1975. In that paper, Anderson provided insights on the great richness of species found in soils, but emphasized that the mechanisms contributing to the high species richness belowground were largely unknown. Yet, exploration of the mechanisms driving species richness has focused, almost exclusively, on above-ground plant and animal communities, and nearly 35 years later we have several new hypotheses but are not much closer to revealing why soils are so rich in species. One persistent but untested hypothesis is that species richness is promoted by small-scale environmental heterogeneity., Methodology/principal Findings: To test this hypothesis we manipulated small-scale heterogeneity in soil properties in a one-year field experiment and investigated the impacts on the richness of soil fauna and evenness of the microbial communities. We found that heterogeneity substantially increased the species richness of oribatid mites, collembolans and nematodes, whereas heterogeneity had no direct influence on the evenness of either the fungal, bacterial or archaeal communities or on species richness of the large and mobile mesostigmatid mites. These results suggest that the heterogeneity-species richness relationship is scale dependent., Conclusions: Our results provide direct evidence for the hypothesis that small-scale heterogeneity in soils increase species richness of intermediate-sized soil fauna. The concordance of mechanisms between above and belowground communities suggests that the relationship between environmental heterogeneity and species richness may be a general property of ecological communities.

Herbivory and climate are key environmental drivers, shaping ecosystems at high latitudes. Here, we focus on how these two drivers act in concert, influencing the high arctic tundra. We aim to investigate mechanisms through which herbivory by geese influences vegetation and soil processes in tundra ecosystems under ambient and warmed conditions. To achieve this, two grazing treatments, clipping plus faecal additions and moss removal, were implemented in conjunction with passive warming. Our key finding was that, in many cases, the tundra ecosystem response was determined by treatment impacts on the moss layer. Moss removal reduced the remaining moss layer depth by 30% and increased peak grass biomass by 27%. These impacts were probably due to observed higher soil temperatures and decomposition rates associated with moss removal. The positive impact of moss removal on grass biomass was even greater with warming, further supporting this conclusion. In contrast, moss removal reduced dwarf shrub biomass possibly resulting from increased exposure to desiccating winds. An intact moss layer buffered the soil to increased air temperature and as a result there was no response of vascular plant productivity to warming over the course of this study. In fact, moss removal impacts on soil temperature were nearly double those of warming, suggesting that the moss layer is a key component in controlling soil conditions. The moss layer also absorbed nutrients from faeces, promoting moss growth. We conclude that both herbivory and warming influence this high arctic ecosystem but that herbivory is the stronger driver of the two. Disturbance to the moss layer resulted in a shift towards a more grass-dominated system with less abundant mosses and shrubs, a trend that was further enhanced by warming. Thus herbivore impacts to the moss layer are key to understanding arctic ecosystem response to grazing and warming.

At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These rapid changes may be a bellwether of changes to come at lower latitudes and have the potential to affect ecosystem services related to natural resources, food production, climate regulation, and cultural integrity. We highlight areas of ecological research that deserve priority as the Arctic continues to warm.

Debate on the relationship between diversity and stability has been driven by the recognition that species loss may influence ecosystem properties and processes. We conducted a litterbag experiment in the Scottish Highlands, United Kingdom, to examine the effects of altering plant litter diversity on decomposition, microbial biomass, and microfaunal abundance. The design of treatments was fully factorial and included five species from an upland plant community (silver birch, Betula pendula; Scots' pine, Pinus sylvestris; heather, Calluna vulgaris; bilberry, Vaccinium myrtillus; wavy-hair grass, Deschampsia flexuosa); species richness ranged from one to five species. We tested the effects of litter species richness and composition on variable means, whether increasing litter species richness reduced variability in the decomposer system, and whether any richness-variability relationships were maintained over time (196 vs. 564 days). While litter species composition effects controlled variable means, we revealed reductions in variability with increasing litter species richness, even after accounting for differences between litter types. These findings suggest that higher plant species richness per se may result in more stable ecosystem processes (e.g., decomposition) and decomposer communities. Negative richness-variation relationships generally relaxed over time, presumably because properties of litter mixtures became more homogeneous. However, given that plant litter inputs continue to enter the belowground system over time, we conclude that variation in ecosystem properties may be buffered by greater litter species richness.

This paper reports on the intervention phase of a participatory action study designed to improve the practice environment within a critical care unit in a research teaching hospital. The intervention strategy involved the hiring of a facilitator who worked with unit staff to engage in a process of addressing their priority issues related to the practice environment. Examples of interventions included staff retreats, communication workshops, task groups and leadership training. Challenges and key learnings are reported.

High-latitude ecosystems store large amounts of carbon (C); however, the C storage of these ecosystems is under threat from both climate warming and increased levels of herbivory. In this study we examined the combined role of herbivores and climate warming as drivers of CO2 fluxes in two typical high-latitude habitats (mesic heath and wet meadow). We hypothesized that both herbivory and climate warming would reduce the C sink strength of Arctic tundra through their combined effects on plant biomass and gross ecosystem photosynthesis and on decomposition rates and the abiotic environment. To test this hypothesis we employed experimental warming (via International Tundra Experiment [ITEX] chambers) and grazing (via captive Barnacle Geese) in a three-year factorial field experiment. Ecosystem CO2 fluxes (net ecosystem exchange of CO2, ecosystem respiration, and gross ecosystem photosynthesis) were measured in all treatments at varying intensity over the three growing seasons to capture the impact of the treatments on a range of temporal scales (diurnal, seasonal, and interannual). Grazing and warming treatments had markedly different effects on CO2 fluxes in the two tundra habitats. Grazing caused a strong reduction in CO2 assimilation in the wet meadow, while warming reduced CO2 efflux from the mesic heath. Treatment effects on net ecosystem exchange largely derived from the modification of gross ecosystem photosynthesis rather than ecosystem respiration. In this study we have demonstrated that on the habitat scale, grazing by geese is a strong driver of net ecosystem exchange of CO2, with the potential to reduce the CO2 sink strength of Arctic ecosystems. Our results highlight that the large reduction in plant biomass due to goose grazing in the Arctic noted in several studies can alter the C balance of wet tundra ecosystems. We conclude that herbivory will modulate direct climate warming responses of Arctic tundra with implications for the ecosystem C balance; however, the magnitude and direction of the response will be habitat-specific.

The objective of this pilot project was to determine whether engaging critical care unit staff in designing and implementing enhancements to the practice environment would positively impact the clinical environment and staff outcomes. The project used a one-group pre-post test design and a participatory action process. Significant changes in the practice environment were observed in the priority areas identified by the unit staff. Results indicated that team collaboration and respectful work relationships improved following interventions.

Mosses are one of the most diverse and widespread groups of plants and often form the dominant vegetation in montane, boreal and arctic ecosystems. However, unlike higher plants, mosses lack developed root and vascular systems, which is thought to limit their access to soil nutrients. Here, we test the ability of two physiologically and taxonomically distinct moss species to take up soil- and wet deposition-derived nitrogen (N) in natural intact turfs using stable isotopic techniques (15N). Both species exhibited increased concentrations of shoot 15N when exposed to either soil- or wet deposition-derived 15N, demonstrating conclusively and for the first time, that mosses derive N from the soil. Given the broad physiological and taxonomic differences between these moss species, we suggest soil N uptake may be common among mosses, although further studies are required to test this prediction. Soil N uptake by moss species may allow them to compete for soil N in a wide range of ecosystems. Moreover, since many terrestrial ecosystems are N limited, soil N uptake by mosses may have implications for plant community structure and nutrient cycling. Finally, soil N uptake may place some moss species at greater risk from N pollution than previously appreciated.

The impact of reduced light conditions as an indirect effect of nitrogen (N) deposition was determined on three mosses in a montane ecosystem, where sedge and grass cover increase due to N enrichment. Additionally, in the greenhouse we established the importance of low light to moss growth as an indirect N deposition effect relative to the direct toxic effects of N. The amount of light reaching the moss layer was strongly and negatively related to graminoid abundance. Mosses showed differing sensitivities to reduced light in the field. Racomitrium lanuginosum biomass was found to be highest under high-light conditions, Polytrichum alpinum at intermediate light levels, whilst that of Dicranum fuscescens was unrelated to light availability. Moreover, Racomitrium biomass decreased with increasing amounts of graminoid litter, whereas the other species were little affected. All three mosses responded differently to the combination of elevated N (20 vs 10 kg N ha(-1) year(-1)) and reduced light (60 and 80% reduction) in the greenhouse. Racomitrium growth was strongly influenced by both light reduction and elevated N, in combination reducing shoot biomass up to 76%. There was a tendency for Dicranum growth to be modestly reduced by elevated N when shaded, causing up to 19% growth reduction. Polytrichum growth was not influenced by elevated N but was reduced up to 40% by shading. We conclude that competition for light, induced by vascular plants, can strongly influence moss performance even in unproductive low biomass ecosystems. The effects of reduced light arising from N pollution can be as important to mosses as direct toxicity from N deposition. Yet, different sensitivities of mosses to both toxic and shading effects of elevated N prevent generalisation and can lead to competitive species replacement within moss communities. This study demonstrates the importance of understanding moss-vascular plant interactions to allow interpretation and prediction of ecosystem responses to anthropogenic drivers such as atmospheric N deposition or climate change.

Soil net N-mineralization rate was measured along a successional gradient in salt-marsh sites that were grazed by vertebrate herbivores, and in 5-year-old exclosures from which the animals were excluded. Mineralization rate was significantly higher at ungrazed than at grazed sites. In the absence of grazing, mineralization rate increased over the course of succession, whereas it remained relatively low when sites were grazed. The largest differences in mineralization rate between grazed and ungrazed sites were found at late successional stages where grazing pressure was lowest. The amount of plant litter was significantly lower at grazed sites. In addition, the amount of litter and potential litter (non-woody, live shoots) was linearly related to net N-mineralization rate. This implies that herbivores reduced mineralization rate by preventing litter accumulation. Bulk density was higher at grazed salt-marsh sites than at ungrazed sites. This factor may also have contributed to the differences in net N-mineralization rate between grazed and ungrazed sites.

An acute care hospital was closed by the British Columbia Ministry of Health in 1993. A research study was conducted to investigate the ways closure of the hospital affected hospital employees and to identify ways to facilitate the closure/reorganization process. Unstructured interviews were conducted with 25 employees around the time of closure and six months after the closure. In the category Living with Closure, six themes arose from the qualitative analysis. They related to (1) provision of information; (2) effect of closure on the working environment and colleagues; (3) perceived stress; (4) recognition of one's worth; (5) provision of support services; and (6) the process of having a new job. The authors offer recommendations stemming from the analysis, which are intended to assist others planning for future hospital reorganizations or closures.

In this study we accumulate evidence that brown hare competes with brent goose for food resources in a temperate salt marsh. We show that both species overlap in habitat use and share food plants. The two herbivores mainly used the common habitat at different times of the day, with hares active in the dark and geese during the daylight. During the morning and evening, however, the habitat was exploited simultaneously. Food availability was manipulated by excluding brent geese on both small-scale (30 m 2 ) and large-scale (0.96 ha) plots, while hares had free access everywhere. Exclusion of brent geese enhanced the level of utilisation by hares in both Festuca and Puccinellia dominated marshes, which are among the most intensively grazed parts of the salt marsh. The increase in hare grazing pressure following goose exclusion was stronger, when the adjacent control plots had attracted more goose visitation. When geese were excluded, the decrease in Festuca consumption by geese was completely matched by increased hare grazing, while for Puccinellia only part of the `surplus' was harvested. Enhanced levels of hare utilisation were not due to geese interfering directly with hare, nor due to hares avoiding goose droppings. Considering the interaction from the other perspective, hares were observed to disturb geese effectively in every spring. This might have reduced exploitation by geese of the shared resources. On the basis of our experimental results, we conclude that in this salt- marsh system competition for food with brent geese plays a role in the habitat use of hares, and that hares can reduce goose exploitation of shared habitats.

Objective: To conduct a feasibility study on stress management for patients with heart disease; more specifically, to test the availability of patients, determine dropout rates, and investigate the sensitivity to change of a large number of psychologic and biologic stress indexes., Design: Random assignment, two-group clinical trial., Setting: Pacific Northwest university-affiliated teaching hospital., Patients: Forty-five patients with heart disease (mean age 56 years), who either had a myocardial infarction or coronary bypass surgery., Outcome Measures: Hostility, subjective distress, resting electrocardiogram, resting blood pressure and blood pressure reactivity to a psychologic stressor, and blood lipid, cortisol, and catecholamine levels., Intervention: Patients were randomly assigned to either (1) exercise rehabilitation (ER) and an 8-week stress management (SM) program (ER + SM) or (2) ER only. Although the recruitment rate was satisfactory, 67% of patients assigned to the control condition and 40% of the SM subjects were not available for posttesting., Results: Computed effect sizes indicated that blood pressure reactivity to a psychologic challenge was reduced after treatment in the ER + SM group but not in ER group. The ER + SM group showed improvement in perceived health status and had clinically meaningful reductions in triglyceride levels, whereas the ER group did not. The ER group had a reduction in high-density lipoproteins, whereas the high-density lipoprotein levels of the ER + SM group did not change., Conclusions: Patients randomly assigned to a control condition may be less willing to participate in time-consuming and invasive posttests than treated patients. Reducing the invasiveness of measurement may increase cost-effectiveness and reduce the dropout rate under controlled conditions. Blood pressure reactivity to a psychologic stress test and changes in serum lipid levels may be sensitive and cost-effective measures to include in future studies of cardiac rehabilitation.

In previous studies basophil-bound IgE was measured by means of quantitative immunofluorescence miscroscopy. But mast cells are of particular importance in local atopic reactions, we thought it necessary to investigate the IgE-load on both cell types. The amount of mast cell-bound IgE can be estimated in a semiquantitative way by end point titration with a fluoresceinated sheep antihuman IgE (FlaIgE). The amount of mast cell-bound IgE was estimated this way in tonsils, adenoids, bronchial and tracheal tissues, and was compared with the amount of IgE on the basophils. A correlation was found between the IgE-load on mast cells and on basophils. Atopic patients had a higher mast cell fluorescence titer (MCFT) than nonatopic controls. It was demonstrated that, as on basophils, the IgE level of the serum contributes to this difference.