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Natural State (natural + state)

Distribution by Scientific Domains

Life Sciences	33%

Selected Abstracts

Use of episcopic differential interference contrast microscopy to identify bacterial biofilms on salad leaves and track colonization by Salmonella Thompson

ENVIRONMENTAL MICROBIOLOGY, Issue 4 2008
J. C. Warner
Summary Zoonotic pathogens such as Salmonella can cause gastrointestinal illness if they are ingested with food. Foods such as salads pose a greater risk because they are consumed raw and have been the source of major outbreaks of disease from fresh produce. The novel light microscopy methods used in this study allow detailed, high resolution imaging of the leaf surface environment (the phyllosphere) and allow pathogen tracking. Episcopic differential interference contrast microscopy coupled with epifluorescence was used to view the natural microflora in situ on salad leaves and their topographical distribution. Fluorescent nucleic acid staining was used to differentiate between bacterial colonists and inorganic debris. Salmonella enterica serovar Thompson expressing green fluorescent protein was inoculated onto individual spinach leaves for 24 h at 22°C in order to observe spatial and temporal patterning of colonization on the two surfaces of each leaf under different osmotic conditions. The results obtained show that salad leaves are host to high numbers of bacteria, typically 105 per square millimetre. Cells are present in complex three-dimensional aggregations which often have a slimy appearance, suggesting the presence of biofilms. Washing of the leaves had little effect on the number of adherent pathogens, suggesting very strong attachment. Episcopic differential interference contrast microscopy is a rapid alternative to both scanning electron microscopy and confocal laser scanning microscopy for visualizing leaf topography and biofilm formation in the natural state. [source]

Instream and catchment characteristics affecting the occurrence and population density of brown trout, Salmo trutta L., in forest brooks of a boreal river basin

FISHERIES MANAGEMENT & ECOLOGY, Issue 6 2001
E. Jutila
The occurrence and density of , 1+ brown trout, Salmo trutta L., and their relationship with prevailing instream and catchment characteristics were studied in 50 small forest streams, partially dredged for forest ditching. The occurrence of trout at a stream site was largely determined by the abundance of pools, size of upper catchment and water pH. Moreover, at sites where trout occurred, the abundance of pools was lower at dredged locations than at those in a natural state. In riffles in a natural state, there was a positive relationship between trout density and three instream variables: the abundance of stream pools, cascades and instream vegetation, while an inverse relationship was found with the abundance of substratum of 2,10 cm in diameter. Of the catchment variables, correspondingly, the proportion of forest in the upper catchment was positively related and the proportion of peatland negatively related to trout density. No significant regression model could be fitted for dredged riffles. The possibility of enhancing trout populations in dredged riffles is discussed. [source]

Atmospheric nitrogen deposition has caused nitrogen enrichment and eutrophication of lakes in the northern hemisphere

GLOBAL CHANGE BIOLOGY, Issue 4 2006
ANN-KRISTIN BERGSTRÖM
Abstract We compiled chemical data and phytoplankton biomass (PB) data (chlorophyll a) from unproductive lakes in 42 different regions in Europe and North America, and compared these data to inorganic nitrogen (N) deposition over these regions. We demonstrate that increased deposition of inorganic N over large areas of Europe and North America has caused elevated concentrations of inorganic N in lakes. In addition, the unproductive lakes in high N deposition areas had clearly higher PB relative to the total phosphorus (P) concentrations illustrating that the elevated inorganic N concentrations has resulted in eutrophication and increased biomass of phytoplankton. The eutrophication caused by inorganic N deposition indicates that PB yield in a majority of lakes in the northern hemisphere is (was) limited by N in their natural state. We, therefore, suggest that P limitation largely concerns lakes where the balance between N and P has been changed because of increased anthropogenic input of N. [source]

Estimating Ground Water Recharge from Topography, Hydrogeology, and Land Cover

GROUND WATER, Issue 1 2005
Douglas S. Cherkauer
Proper management of ground water resources requires knowledge of the rates and spatial distribution of recharge to aquifers. This information is needed at scales ranging from that of individual communities to regional. This paper presents a methodology to calculate recharge from readily available ground surface information without long-term monitoring. The method is viewed as providing a reasonable, but conservative, first approximation of recharge, which can then be fine-tuned with other methods as time permits. Stream baseflow was measured as a surrogate for recharge in small watersheds in southeastern Wisconsin. It is equated to recharge (R) and then normalized to observed annual precipitation (P). Regression analysis was constrained by requiring that the independent and dependent variables be dimensionally consistent. It shows that R/P is controlled by three dimensionless ratios: (1) infiltrating to overland water flux, (2) vertical to lateral distance water must travel, and (3) percentage of land cover in the natural state. The individual watershed properties that comprise these ratios are now commonly available in GIS data bases. The empirical relationship for predicting R/P developed for the study watersheds is shown to be statistically viable and is then tested outside the study area and against other methods of calculating recharge. The method produces values that agree with baseflow separation from streamflow hydrographs (to within 15% to 20%), ground water budget analysis (4%), well hydrograph analysis (12%), and a distributed-parameter watershed model calibrated to total streamflow (18%). It has also reproduced the temporal variation over 5 yr observed at a well site with an average error < 12%. [source]

The Benefits of Sunflower Oleodistillate (SOD) in Pediatric Dermatology

PEDIATRIC DERMATOLOGY, Issue 6 2009
Lawrence F. Eichenfield M.D.
In its natural state, the oil contains high levels of essential fatty acids, particularly linoleic acid, which has skin barrier-enhancing properties. A sunflower oleodistillate (SOD), which is produced through a molecular distillation process without the use of solvents, has been shown to increase the epidermal key lipid synthesis and to reduce inflammation in vitro and in animal models. It has also been shown to activate peroxisome proliferative-activated receptor-, (PPAR-,) in vitro. As PPAR-, agonists have been shown to stimulate keratinocyte differentiation, improve barrier function, and enhance lipid metabolism in the skin, it has been suggested that SOD might also be efficacious in atopic dermatitis (AD). An initial clinical evaluation of the care effect of a 2% SOD emulsion in 20 adult volunteers with atopic skin revealed the moisturizing properties of SOD. Finally, a strong steroid-sparing effect and a positive effect on quality-of-life parameters were clearly demonstrated for the 2% SOD cream in studies in infants and babies with AD. [source]

Hybrid Research Models: Natural Opportunities for Examining Mental Health in Context

CLINICAL PSYCHOLOGY: SCIENCE AND PRACTICE, Issue 1 2006
Marc S. Atkins
The articles in this series promote hybrid research models to bridge the gap between efficacy and effectiveness. We suggest that efforts such as those described in these articles are long overdue. Given the enormous public health consequences of the lack of available and effective mental health services, we no longer can afford research that neglects the natural state of affairs or that leaves others to translate research into practice. It is time to acknowledge that the process of testing interventions in the university for transfer to the community is neither efficient nor empirically justified. Guided by the articles in this series, we focus on the ways in which hybrid models can provide natural opportunities to advance the field and lead to a new generation of research that is both contextually relevant and methodologically rigorous. An iterative process of research and practice is proposed that can lead to stronger theories and methods and enhanced understanding of mental health in context. [source]