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PubMed2005

Molecular cloning and functional analysis of a novel 6&1-FEH from wheat (Triticum aestivum L.) preferentially degrading small graminans like bifurcose.

Like barley and other cereals, wheat (Triticum aestivum L.) accumulates branched graminan-type fructans containing both beta-(2,1) and beta-(2,6) fructosyl linkages, mainly with a quite low degree of polymerization (DP). 1&6-kestotetraose (bifurcose) is the major fructan oligosaccharide accumulating in crown tissues and leaves of cereals exposed to chilling. The fructan exohydrolase (FEH) cDNAs 1-FEH w1 and w2 were previously cloned from wheat crowns sampled in mid-November. Here, we report the cloning and functional analysis of another FEH cDNA from a mid-November wheat crown cDNA library. The cDNA encodes a long open reading frame (ORF) of 595 amino acids. Like other FEHs, it has a low iso-electric point (5.2) and it groups together with cell-wall type invertases and not with vacuolar invertases. The deduced amino acid sequence shows 67% identity to wheat 1-FEH w1 and w2. Functional characterization of the recombinant proteins in Pichia pastoris demonstrated that the recombinant enzyme had FEH activity towards the pure compounds 1-kestose, 6-kestose, 1,1-nystose and 1,1,1-kestopentaose. However, when incubated with its putative natural substrates (a mixture of low DP graminans from wheat crowns), it was shown that 1&6-kestotetraose (bifurcose) was preferentially removed from the graminan mixture. High DP wheat graminan and bacterial levan were only poor substrates. No hydrolase activities could be detected towards sucrose and high DP inulin, convincingly demonstrating that the enzyme is not a classic invertase or 1-FEH. The enzyme was termed 6&1-FEH w1. Northern blot analyses showed that 6&1-FEH w1 was expressed in crown tissue from autumn through winter under snow, while the expression levels in leaves were minimal or not detectable. The results strongly suggest that this unique FEH might play an important role in the degradation of branched, low DP wheat graminan (like bifurcose) in wheat crowns in the high fructan content season.

Amino Acid Sequence↗
PubMed2005

Evolutionary analysis of a large mtDNA translocation (numt) into the nuclear genome of the Panthera genus species.

Translocation of cymtDNA into the nuclear genome, also referred to as numt, has been reported in many species, including several closely related to the domestic cat (Felis catus). We describe the recent transposition of 12,536 bp of the 17 kb mitochondrial genome into the nucleus of the common ancestor of the five Panthera genus species: tiger, P. tigris; snow leopard, P. uncia; jaguar, P. onca; leopard, P. pardus; and lion, P. leo. This nuclear integration, representing 74% of the mitochondrial genome, is one of the largest to be reported in eukaryotes. The Panthera genus numt differs from the numt previously described in the Felis genus in: (1) chromosomal location (F2-telomeric region vs. D2-centromeric region), (2) gene make up (from the ND5 to the ATP8 vs. from the CR to the COII), (3) size (12.5 vs. 7.9 kb), and (4) structure (single monomer vs. tandemly repeated in Felis). These distinctions indicate that the origin of this large numt fragment in the nuclear genome of the Panthera species is an independent insertion from that of the domestic cat lineage, which has been further supported by phylogenetic analyses. The tiger cymtDNA shared around 90% sequence identity with the homologous numt sequence, suggesting an origin for the Panthera numt at around 3.5 million years ago, prior to the radiation of the five extant Panthera species.

Animals↗
PubMed2006

Impact of weather and climate on the incidence of acute coronary syndromes.

BACKGROUND: First investigations of the interactions between weather and the incidence of acute myocardial infarctions date back to 1938. The early observation of a higher incidence of myocardial infarctions in the cold season could be confirmed in very different geographical regions and cohorts. While the influence of seasonal variations on the incidence of myocardial infarctions has been extensively documented, the impact of individual meteorological parameters on the disease has so far not been investigated systematically. Hence the present study intended to assess the impact of the essential variables of weather and climate on the incidence of myocardial infarctions. METHODS: The daily incidence of myocardial infarctions was calculated from a national hospitalization survey. The hourly weather and climate data were provided by the database of the national weather forecast. The epidemiological and meteorological data were correlated by multivariate analysis based on a generalized linear model assuming a log-link-function and a Poisson distribution. RESULTS: High ambient pressure, high pressure gradients, and heavy wind activity were associated with an increase in the incidence of the totally 6560 hospitalizations for myocardial infarction irrespective of the geographical region. Snow- and rainfall had inconsistent effects. Temperature, Foehn, and lightning showed no statistically significant impact. CONCLUSIONS: Ambient pressure, pressure gradient, and wind activity had a statistical impact on the incidence of myocardial infarctions in Switzerland from 1990 to 1994. To establish a cause-and-effect relationship more data are needed on the interaction between the pathophysiological mechanisms of the acute coronary syndrome and weather and climate variables.

Climate↗
PubMed2006

Evaluating the clinical significance of responses by psychiatric inpatients to the mental health subscales of the SF-36.

BACKGROUND: The Mental Health subscales of the Medical Outcomes Short Form Questionnaire (SF-36; [Ware, J.E., Snow, K.K., Kosinski, M., Gandek, B., 1993. SF-36 Health Survey: Manual and Interpretation Guide. Boston: The Health Institute, New England Medical Center]) are increasingly being used to evaluate treatment outcomes, but data to assess the clinical significance of changes are absent. The present study applied Jacobson and Truax's [Jacobson, N.S., Truax, P. 1991. CLINICAL SIGNIFICANCE: a statistical approach to defining meaningful change in psychotherapy research. Journal of Consulting and Clinical Psychology 59, 12-19] criteria for clinical significance to the mental health items of the SF-36. METHOD: Admission and discharge data were collated from 1830 consecutive inpatients at a psychiatric hospital, using the SF-36, the Depression Anxiety Stress Scale, the Quality of Life Enjoyment and Satisfaction Questionnaire and the clinician-rated Health of the Nation Outcome Scale. RESULTS: Appropriate improvement cut-off scores for the mental health subscales of the SF-36 are reported, and significant differences were found between outcome groups according to clinically significant improvement. LIMITATIONS: CLINICAL SIGNIFICANCE as a means of assessing outcome should be used with caution in inpatient settings, as further improvement is often expected upon discharge from the hospital. CONCLUSIONS: Assessing clinically significant improvement is an effective means of measuring treatment outcome in terms of quality of life and symptom improvement in psychiatric care.

Australia↗
PubMed2006

Human hoppers compensate for simultaneous changes in surface compression and damping.

On a range of elastic and damped surfaces, human hoppers and runners adjust leg mechanics to maintain similar spring-like mechanics of the leg and surface combination. In a previous study of adaptations to damped surfaces, we changed surface damping and stiffness simultaneously to maintain constant surface compression. The current study investigated whether hoppers maintain spring-like mechanics of the leg-surface combination when surface damping alone changes (elastic and 1000-4800 N s m(-1)). We found that hoppers adjusted leg mechanics to maintain similar spring-like mechanics of the leg-surface combination and center of mass dynamics on all surfaces. Over the range of surface damping, vertical stiffness of the leg-surface combination increased by only 12% and center of mass displacement decreased by only 6% despite up to 55% less compression of more heavily damped surfaces. In contrast, a simulation predicted a 44% decrease in vertical displacement with no adjustment to leg mechanics. To compensate for the smaller and slower compression of more heavily damped surfaces, the stance legs compressed by up to 4.1 +/- 0.2 cm further and reached peak compression sooner. To replace energy lost by damped surfaces, hoppers performed additional leg work by extending the legs during takeoff by up to 3.1 +/- 0.2 cm further than they compressed during landing. We conclude that humans simultaneously adjust leg compression magnitude and timing, as well as mechanical work output, to conserve center of mass dynamics on damped surfaces. Runners may use similar strategies on natural energy-dissipating surfaces such as sand, mud and snow.

Adult↗
PubMed2006

A degloving foot injury in a traffic accident.

An unusual human remain found on a road became one key to reconstruct the traffic accident. A woman was found dead on a snow-covered road. Her left foot showed a large deficit of skin and underlying fat tissue. The detached skin and tissue were found into her left sock and shoe lying at a distance of 23 m from the body. There were multiple fractures on her back and occipital cranial bone. Severe injuries revealed in heart, liver, and brain. The neck remained intact. These findings suggested that her back has been strongly hit by the object with the flat surface, for example, the front side of a cab-over or truck, from behind at a high speed. Furthermore, the degloving injury in her left foot suggested that a vehicle ran over the foot which faced the vehicle. We reconstructed the accident as follows. Firstly the wheel of the vehicle ran over the victim's foot, and then, the victim turned away from the vehicle. Finally, the front side hit her twisted body from behind, resulting in a traumatic degloving injury.

Accidents, Traffic↗
PubMed2005

Prescribed burning effects on summer elk forage availability in the subalpine zone, Banff National Park, Canada.

The effects of prescribed burning on forage abundance and suitability for elk (Cervus elaphus) during the snow-free season was evaluated in east-central Banff National Park, Canada. Six coniferous forest and mixed shrub-herb plant communities (n=144 plots), and 5223ha of burned (n=131) vegetation <12 years old were sampled using a stratified semi-random design. Sampling units represented various combinations of vegetation, terrain conditions, and stand ages that were derived from digital biophysical data, with plant communities the basic unit of analysis. Burning coniferous forest stands reduced woody biomass, and increased herbaceous forage from 146 to 790 kg/ha. Increases commonly occurred in the percent cover of hairy wild rye (Leymus innovatus (Beal) Pigler) and fireweed (Chamerion angustifolium (L.) Holub.). The herbaceous components of mixed shrub-herb communities increased from 336-747 kg/ha to 517-1104 kg/ha in response to burning (P<0.025, Mann-Whitney U-test). Browse biomass (mostly Salix spp. and Betula nana L.) increased >or=220% (P<or=0.003, Mann-Whitney U-test) from 653 kg/ha in deciduous shrub types. Elk preferences for unburned and burned vegetation-types were assessed as low and moderate, respectively. Potential summer carrying capacity, based on forage availability, increased from eight to 28 elk/100 km2 within burned areas, whereas spring grazing potential rose from 13 to 45 elk/100 km2. Most of the increase (73%) was attributable to changes within burned Engelmann Spruce stands, which composed 58% of the burned area.

Alberta↗
PubMed2006

Generation of urban road dust from anti-skid and asphalt concrete aggregates.

Road dust forms an important component of airborne particulate matter in urban areas. In many winter cities the use of anti-skid aggregates and studded tires enhance the generation of mineral particles. The abrasion particles dominate the PM10 during springtime when the material deposited in snow is resuspended. This paper summarizes the results from three test series performed in a test facility to assess the factors that affect the generation of abrasion components of road dust. Concentrations, mass size distribution and composition of the particles were studied. Over 90% of the particles were aluminosilicates from either anti-skid or asphalt concrete aggregates. Mineral particles were observed mainly in the PM10 fraction, the fine fraction being 12% and submicron size being 6% of PM10 mass. The PM10 concentrations increased as a function of the amount of anti-skid aggregate dispersed. The use of anti-skid aggregate increased substantially the amount of PM10 originated from the asphalt concrete. It was concluded that anti-skid aggregate grains contribute to pavement wear. The particle size distribution of the anti-skid aggregates had great impact on PM10 emissions which were additionally enhanced by studded tires, modal composition, and texture of anti-skid aggregates. The results emphasize the interaction of tires, anti-skid aggregate, and asphalt concrete pavement in the production of dust emissions. They all must be taken into account when measures to reduce road dust are considered. The winter maintenance and springtime cleaning must be performed properly with methods which are efficient in reducing PM10 dust.

Air Pollutants↗
PubMed2006

Decline in ascorbate peroxidase activity--a prerequisite factor for tepal senescence in gladiolus.

Flower senescence was studied in Gladiolus cv. "Snow Princess" over five arbitrarily divided developmental stages (stage 1, half bloom; stage 2, full bloom; stage 3, beginning of wilting; stage 4, 50% wilting; stage 5, complete wilting) in terms of changes in fresh weight, antioxidant enzymes (superoxide dismutase, SOD; ascorbate peroxidase, APX; glutathione reductase, GR) activities and membrane integrity. A significant decrease in tepal fresh weight was observed over the senescence period (after stage 2). Membrane integrity was studied by measuring lipid peroxidation [in terms of thiobarbituric acid reactive substances (TBARS) content] and membrane stability index (MSI) percentage. Maximum TBARS content was recorded in stage 4 (50% wilting). This increase in lipid peroxidation over the senescence period was in close association with high degree of membrane deterioration expressed as decrease in membrane stability index percentage. A significant decrease (two and half-fold) in MSI% in stage 5 (as compared to stage 1) indicates complete membrane deterioration. Progressive increase in endogenous H2O2 level was recorded over senescence period. Maximum H2O2 content (19.7+/-1.4 micromol g(-1) DW) was recorded at stage 5 (complete wilting). Three different patterns were observed in antioxidant enzymes behavior over the senescence period. APX activity was declined significantly as, the flower entered stage 3 (beginning of wilting) from full bloom condition (stage 2). Progressive and significant increase in SOD activity was measured as a function of time. Maximum SOD activity (24.2+/-0.8 U mg(-1) DW) was recorded in stage 5 (three-fold increase over stage 1). GR activity initially increased up to stage 4 (50% wilting) and declined significantly thereafter (approximately seven-fold). An increase in endogenous H2O2 level during senescence may be the result of a programmed down-regulation of APX enzyme activity, which seems to be the prerequisite factor for initiating senescence process in gladiolus tepal.

Antioxidants↗
PubMed2006

The replicator equation on graphs.

We study evolutionary games on graphs. Each player is represented by a vertex of the graph. The edges denote who meets whom. A player can use any one of n strategies. Players obtain a payoff from interaction with all their immediate neighbors. We consider three different update rules, called 'birth-death', 'death-birth' and 'imitation'. A fourth update rule, 'pairwise comparison', is shown to be equivalent to birth-death updating in our model. We use pair approximation to describe the evolutionary game dynamics on regular graphs of degree k. In the limit of weak selection, we can derive a differential equation which describes how the average frequency of each strategy on the graph changes over time. Remarkably, this equation is a replicator equation with a transformed payoff matrix. Therefore, moving a game from a well-mixed population (the complete graph) onto a regular graph simply results in a transformation of the payoff matrix. The new payoff matrix is the sum of the original payoff matrix plus another matrix, which describes the local competition of strategies. We discuss the application of our theory to four particular examples, the Prisoner's Dilemma, the Snow-Drift game, a coordination game and the Rock-Scissors-Paper game.

Animals↗
PubMed2006

Surprising niche for the plant pathogen Pseudomonas syringae.

The biology and ecology of plant pathogenic bacteria have been studied almost exclusively in agricultural contexts. In contrast, for numerous human pathogens their biological activity in niches outside of medical contexts is well-known. Whereas there is increasing evidence that traits fostering survival in 'environmental' niches can be the basis for virulence factors of human pathogens, niches for plant pathogenic bacteria outside of plants or of agricultural settings have not been elucidated. Most phytopathogenic bacteria are not obligate parasites, some of them can be transported to altitudes of several kilometres, they are scrubbed from the atmosphere by rainfall, and thus they are presumably transported to and might survive in a wide range of habitats. We isolated Pseudomonas syringae from river epilithon (rock-attached biofilms composed of algae, diatoms, rotifers, bacteria and nematodes) at densities up to 6000 cells g(-1) in France and the USA, some in pristine settings where waters flowed directly from snow melt and had not passed through agricultural zones. These strains induced hypersensitivity in indicator plants (tobacco) suggesting the presence of functional pathogenicity systems, and many induced disease in 1-7 of the plant species tested and produced a syringomycin-like toxin. Strains also were resistant to some antibiotics used to control plant diseases but not to copper sulphate. Sequencing of the 16S rDNA of epilithon strains and of reference strains of P. syringae revealed that a genetic lineage containing the strains with the broadest host range was distributed across several continents. Is it likely that wide spread dissemination of P. syringae occurs via aerosols and precipitation. This work highlights our limited understanding of non-agricultural niches in the ecology and evolution of plant pathogenic bacteria, of their role in the development of agricultural epidemics both as sources of inoculum and as sources of novel traits that may enhance bacterial pathogenicity and fitness.

Bacterial Physiological Phenomena↗
PubMed2006

Activity and heart rate in semi-domesticated reindeer during adaptation to emergency feeding.

Although reindeer are well adapted to limited food resources during winter, semi-domesticated reindeer are regularly fed when snow conditions are bad in order to prevent starvation. Feeding sometimes results in health problems and loss of animals. This study was made to assess if activity pattern in reindeer could be used as a tool for the reindeer herder in early detection of animals that are not adapting to feeding. The frequency of 10 behavioural categories was recorded in five groups of penned, eight-month-old, female semi-domesticated reindeer. Three reindeer per group were fitted with heart rate monitors. Lying was the most frequent behaviour, whilst there were few cases of agonistic behaviour. Heart rate varied during the day, with peaks during feeding and low heart rates in the early morning. Restricted feed intake resulted in more locomotion and seeking but less ruminating compared to feeding ad libitum. This was followed by a generally lower heart rate in reindeer in the restricted groups compared to controls. Subsequent feeding with different combinations of lichens, silage and pellets ad libitum resulted initially in significantly more of the animals lying curled up, compared to controls, combined with increased heart rates. As the experiment continued the general activity pattern, as well as the heart rate, gradually became more similar in all groups. Lying curled was the behavioural indicator most consistently affected by feed deprivation and adaptation to feeding and may thus be a useful indicator to distinguish individual reindeer that are not adjusting to feeding.

Acclimatization↗
PubMed2006

A pollen-specific polygalacturonase from lily is related to major grass pollen allergens.

A pollen-specific gene from lily (Lilium longiflorum Thunb. cv. Snow Queen), designated LLP-PG, was characterized. Southern blots of lily genomic DNA indicated that LLP-PG is a member of a small gene family. A thorough sequence analysis revealed that the LLP-PG gene is interrupted by two introns and encodes a protein of 413 amino acids, with a calculated molecular mass of 44 kDa, and a pI of 8.1. Evaluation of the hydropathy profile showed that the protein has a hydrophobic segment at the N-terminus, indicating the presence of a putative signal peptide. A sequence similarity search showed a significant homology of the encoded protein to pollen polygalacturonases (PGs) from various plant species and to an important group (group 13) of grass pollen allergens. The LLP-PG transcript is pollen-specific and it accumulates only at the latest stage during pollen development, in the mature pollen. In contrast to other "late genes" LLP-PG transcript can neither be induced by abscisic acid (ABA) nor by dehydration. Immunoblot analyses of pollen protein extracts from lily, timothy grass and tobacco with IgG antibodies directed against LLP-PG and against the timothy grass pollen allergen, Phl p 13, indicated that lily LLP-PG shares surface-exposed epitopes with pollen PGs from monocotyledonous and dicotyledonous plants. Enzyme-linked immunosorbent assay (ELISA) analyses and inhibition ELISA assays with patients' IgE demonstrated a very low IgE reactivity of lily rLLP-PG and a lack of cross-reactivity between rLLP-PG and the timothy grass pollen allergen, rPhl p 13. These data demonstrated that despite the significant sequence homology and the conserved surface-exposed epitopes LLP-PG represents a low-allergenic member of pollen PGs.

Allergens↗
PubMed2004

Human exposure to contaminants in the traditional Greenland diet.

The traditional diet is a significant source of contaminants to people in Greenland, although contaminant levels vary widely among species and tissue from very low in many to very high in a few. Our study has included cadmium, mercury, selenium, polychlorinated biphenyls (PCB), dichlorophenyltrichloroethane (DDT), chlordane, hexachlorocyclohexanes (HCH), chlorobenzenes, dieldrin and toxaphene in the major species and tissues consumed by Greenlanders. In general, the levels of these are very low in terrestrial species and in muscle of many marine species. High organochlorines concentrations are typically found in blubber of marine mammals and high metal levels in liver and kidney of seals and whales. In this study, the mean intakes of cadmium, chlordanes and toxaphene significantly exceed 'acceptable/tolerable intakes' (ADI/TDI) by a factor between 2.5 and 6. Mean intakes of mercury, PCB and dieldrin also exceed ADI/TDI by up to approximately 50%. However as these figures are mean intakes and as variation in both food intake and contaminant levels is large, the variation of contaminant intake among individuals is also large, and some individuals will be exposed to significantly higher intakes. The mean intakes of DDT, HCH and chlorobenzenes are well below the ADI/TDI values, and it seems unlikely that the TDI for these contaminants normally is exceeded in the Greenland population. The evaluation of contaminant intake in this study points to seal muscle, seal liver, seal kidney, seal blubber and whale blubber as the dominant contributors of contaminants in the traditional diet. Levels in liver from Greenland halibut, snow crab, king eider, kittiwake, beluga and narwhal and kidney of beluga and narwhal are also high but were, with the exception of toxaphene in Greenland halibut liver, not important sources in this study, because they were eaten in low quantities. A way to minimize contaminant intake would be to avoid or limit the consumption of diet items with high contaminant levels. If we assume a traditional diet composition in this study without fish liver, bird liver, seal liver, seal kidney, seal blubber, whale liver, whale kidney and whale blubber, the intake of all contaminants would be below the TDIs for these. This will result in a reduction of the intake of the amount of traditional food of only 24-25%, and it is not likely that this changed diet will result in deficiency of minerals, vitamins or other nutritional compounds.

Adolescent↗
PubMed2005

Heavy metals in Lake Balaton: water column, suspended matter, sediment and biota.

During the period 1999-2002, five sampling cruises have been carried out on Lake Balaton to assess trace metal distribution in the lake and to identify major sources. Eighteen elements, including Cr, Co, Ni, Cu, Zn, Cd, Pb (trace metals) and Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Sr (major metals), were determined in one or more of the lake's compartments. Lower trace metal concentrations in rainwater were observed in June and February 2000, while much higher levels were present in September 2001 (during a storm event) and in snow (February 2000). In the Northern and Western parts of the lake, especially at the inflow of river Zala and the locations of the yacht harbours, metal concentrations were higher in almost all compartments. Because the lake is very shallow, storm conditions also change significantly the metal distributions in the dissolved and particulate phases. The Kis-Balaton protection system located on Zala river functions very efficiently for retaining suspended particulate matter (SPM; 72% retention) and associated metals. Metal concentrations in surface sediments of the lake showed a high variability. After normalisation for the fine sediment fraction, only a few stations including Zala mouth appeared to be enriched in trace metals. In zooplankton, Zn seemed to be much more elevated compared to the other trace metals. Based on the molar ratios of the trace metals in the various compartments and input flows of the lake, several trends could be deduced. For example, molar ratios of the trace metals in the dissolved and solid (suspended particulate matter and sediments) phases in the lake are fairly similar to those in Zala River.

Animals↗
PubMed2005

Mercury distribution and speciation in Lake Balaton, Hungary.

The distribution and speciation of mercury in air, rain, lake water, sediment, and zooplankton in Lake Balaton (Hungary) were investigated between 1999 and 2002. In air, total gaseous mercury (TGM) ranged from 0.4 to 5.9 ng m(-3) and particulate phase mercury (PPM) from 0.01 to 0.39 ng m(-3). Higher concentrations of both TGM and PPM occurred during daytime. Higher concentrations of PPM occurred in winter. In rain and snow, total mercury ranged from 10.8 to 36.7 ng L(-1) in summer but levels up to 191 ng L(-1) in winter. Monomethylmercury (MMHg) concentrations ranged from 0.09 to 1.26 ng L(-1) and showed no seasonal variations. Total Hg in the unfiltered lake water varied spatially, with concentrations ranging from 1.4 to 6.5 ng L(-1). Approximately 70% of the total Hg is dissolved. MMHg levels ranged from 0.08 to 0.44 ng L(-1) as total and from 0.05 to 0.37 ng L(-1) in the dissolved form. Lower Hg concentrations in the water column occurred in winter. In suspended particulate matter and in sediment, total mercury ranged from 9 to 160 ng g(-1) dw, and MMHg ranged from 0.07 to 0.84 ng g(-1) dw. In zooplankton, an average mercury level of 31.0+/-6.8 ng g(-1) dw occurred, with MMHg accounting for approximately 17%. In sediments, suspended-matter- and zooplankton-high Hg and MMHg levels occurred at the mouth of the River Zala, but, in the lake, higher concentrations occurred on the Northern side, and an increasing trend from north-west to north-east was observed. In general, regarding Hg, Lake Balaton can be considered as a relatively uncontaminated site. The high-pH and well-oxygenated water as well as the low organic matter content of the sediment does not favour the methylation of Hg. In addition, bioconcentration and bioaccumulation factors are relatively low compared to other aquatic systems.

Air Pollutants↗
PubMed2006

Linked models to assess the impacts of climate change on nitrogen in a Norwegian river basin and FJORD system.

Dynamically downscaled data from two Atmosphere-Ocean General Circulation Models (AOGCMs), ECHAM4 from the Max-Planck Institute (MPI), Germany and HadAm3H from the Hadley Centre (HAD), UK, driven with two scenarios of greenhouse gas emissions (IS92a and A2, respectively) were used to make climate change projections. These projections were then used to drive four effect models linked to assess the effects on hydrology, and nitrogen (N) concentrations and fluxes, in the Bjerkreim river basin (685-km(2)) and its coastal fjord, southwestern Norway. The four effect models were the hydrological model HBV, the water quality models MAGIC, INCA-N and the NIVA FJORD model. The downscaled climate scenarios project a general temperature increase in the study region of approximately 1 degrees C by 2030-2049 (MPI IS92a) and approximately 3 degrees C by 2071-2100 (HAD A2). Both scenarios imply increased winter precipitation, whereas the projections of summer and autumn precipitation are quite different, with the MPI scenario projecting a slight increase and the HAD scenario a significant decrease. As a response to increased winter temperature, the HBV model simulates a dramatic reduction of snow accumulation in the upper parts of the catchment, which in turn lead to higher runoff during winter and lower runoff during snowmelt in the spring. With the HAD scenario, runoff in summer and early autumn is substantially reduced as a result of reduced precipitation, increased temperatures and thereby increased evapotranspiration. The water quality models, MAGIC and INCA-N project no major changes in nitrate (NO(3)(-)) concentrations and fluxes within the MPI scenario, but a significant increase in concentrations and a 40-50% increase in fluxes in the HAD scenario. As a consequence, the acidification of the river could increase, thus offsetting ongoing recovery from acidification due to reductions in acid deposition. Additionally, the increased N loading may stimulate growth of N-limited benthic algae and macrophytes along the river channels and lead to undesirable eutrophication effects in the estuarine area. Simulations made by the FJORD model and the HAD scenario indicate that primary production in the estuary might increase up to 15-20%, based on the climate-induced changes in river flow and nitrate concentrations alone.

Acid Rain↗
PubMed2006

From dust to dose: Effects of forest disturbance on increased inhalation exposure.

Ecosystem disturbances that remove vegetation and disturb surface soils are major causes of excessive soil erosion and can result in accelerated transport of soils contaminated with hazardous materials. Accelerated wind erosion in disturbed lands that are contaminated is of particular concern because of potential increased inhalation exposure, yet measurements regarding these relationships are lacking. The importance of this was highlighted when, in May of 2000, the Cerro Grande fire burned over roughly 30% of Los Alamos National Laboratory (LANL), mostly in ponderosa pine (Pinus ponderosa) forest, and through areas with soils containing contaminants, particularly excess depleted and natural uranium. Additionally, post-fire thinning was performed in burned and unburned forests on about 25% of LANL land. The first goal of this study was to assess the potential for increased inhalation dose from uranium contaminated soils via wind-driven resuspension of soil following the Cerro Grande Fire and subsequent forest thinning. This was done through analysis of post-disturbance measurements of uranium air concentrations and their relationships with wind velocity and seasonal vegetation cover. We found a 14% average increase in uranium air concentrations at LANL perimeter locations after the fire, and the greatest air concentrations occurred during the months of April-June when wind velocities are highest, no snow cover, and low vegetation cover. The second goal was to develop a methodology to assess the relative contribution of each disturbance type towards increasing public and worker exposure to these resuspended soils. Measurements of wind-driven dust flux in severely burned, moderately burned, thinned, and unburned/unthinned forest areas were used to assess horizontal dust flux (HDF) in these areas. Using empirically derived relationships between measurements of HDF and respirible dust, coupled with onsite uranium soil concentrations, we estimate relative increases in inhalation doses for workers ranging from 15% to 38%. Despite the potential for increased doses resulting from these forest disturbances, the estimated annual dose rate for the public was <1 microSv yr(-1), which is far below the dose limits for public exposures, and the upper-bound dose rate for a LANL worker was estimated to be 140 microSv yr(-1), far below the 5 x 10(4) microSv yr(-1) occupational dose limit. These results show the importance of ecosystem disturbance in increasing mobility of soil-bound contaminants, which can ultimately increase exposure. However, it is important to investigate the magnitude of the increases when deciding appropriate strategies for management and long-term stewardship of contaminated lands.

Air Pollutants, Radioactive↗