Evaluation of sources of variation on in vitro fermentation kinetics of feedstuffs in a gas production system.

PubMed

Keim, Juan P; Alvarado-Gilis, Christian; Arias, Rodrigo A; Gandarillas, Mónica; Cabanilla, Jaime

2017-10-01

The aim of this study was to evaluate the effect of different sources of variation in gas production technique on the in vitro gas production kinetics of feedstuffs. Triplicates of commercial concentrate, grass silage, grass hay and grass pasture were incubated in three experiments: experiment 1 assessed two agitation methods; experiment 2 evaluated different rumen inocula (pooled or different donor cows for each incubation run); and experiment 3 used Goering-Van Soest or Mould buffers for media preparation. Gas production data were fitted into the Michaelis-Menten model and then subjected to analysis of variance. Gas production (GP) at 48 h and asymptote gas production (A) were lower when bottles were continuously under horizontal movement. Time to produce half and 75% of A, and A were affected by rumen inocula, while buffer type affected time to produce half and 25% of A and GP. No interactions between substrates and sources of variation were observed, suggesting that the effects of substrates on GP parameters were not modified. It is concluded that comparison of numerical data from in vitro experiments that follow different protocols must be done carefully. However, the ranking of different substrates is more robust and less affected by the sources of variation. © 2017 Japanese Society of Animal Science.

Microhabitats and canopy cover moderate high summer temperatures in a fragmented Mediterranean landscape.

PubMed

Keppel, Gunnar; Anderson, Sharolyn; Williams, Craig; Kleindorfer, Sonia; O'Connell, Christopher

2017-01-01

Extreme heat events will become more frequent under anthropogenic climate change, especially in Mediterranean ecosystems. Microhabitats can considerably moderate (buffer) the effects of extreme weather events and hence facilitate the persistence of some components of the biodiversity. We investigate the microclimatic moderation provided by two important microhabitats (cavities formed by the leaves of the grass-tree Xanthorrhoea semiplana F.Muell., Xanthorrhoeaceae; and inside the leaf-litter) during the summer of 2015/16 on the Fleurieu Peninsula of South Australia. We placed microsensors inside and outside these microhabitats, as well as above the ground below the forest canopy. Grass-tree and leaf-litter microhabitats significantly buffered against high temperatures and low relative humidity, compared to ground-below-canopy sensors. There was no significant difference between grass-tree and leaf-litter temperatures: in both microhabitats, daily temperature variation was reduced, day temperatures were 1-5°C cooler, night temperatures were 0.5-3°C warmer, and maximum temperatures were up to 14.4°C lower, compared to ground-below-canopy sensors. Grass-tree and leaf-litter microhabitats moderated heat increase at an average rate of 0.24°C temperature per 1°C increase of ambient temperature in the ground-below-canopy microhabitat. The average daily variation in temperature was determined by the type (grass-tree and leaf-litter versus ground-below-canopy) of microhabitat (explaining 67%), the amount of canopy cover and the area of the vegetation fragment (together explaining almost 10% of the variation). Greater canopy cover increased the amount of microclimatic moderation provided, especially in the leaf-litter. Our study highlights the importance of microhabitats in moderating macroclimatic conditions. However, this moderating effect is currently not considered in species distribution modelling under anthropogenic climate change nor in the management of vegetation. This shortcoming will have to be addressed to obtain realistic forecasts of future species distributions and to achieve effective management of biodiversity.

APEX simulation: environmental benefits of agroforestry and grass buffers on corn-soybean watersheds

USDA-ARS?s Scientific Manuscript database

The Agricultural Policy Environmental Extender (APEX) model has the ability to simulate the effects of vegetative filter strips on runoff and pollutant loadings from agricultural watersheds. The objectives of this study were to calibrate and validate the APEX model for three adjacent watersheds and...

Apex simulation: environmental benefits of agroforestry and grass buffers for corn-soybean watersheds

USDA-ARS?s Scientific Manuscript database

The Agricultural Policy Environmental Extender (APEX) model is used to simulate the effects of vegetative filter strips on runoff and pollutant loadings from agricultural watersheds. A long-term paired watershed study under corn (Zea mays L-soybean [Glycine max (L.) Merr.] rotation with agroforestr...

Ecotype-specific improvement of nitrogen status in European grasses after drought combined with rewetting

NASA Astrophysics Data System (ADS)

Arfin Khan, Mohammed A. S.; Kreyling, Juergen; Beierkuhnlein, Carl; Jentsch, Anke

2016-11-01

Drought stress and associated low soil moisture can decrease N status of forage plants by reducing nitrogen (N) uptake. Conversely, rainfall and associated favorable soil moisture can improve plant N status. Yet, it is unclear to which degree drought combined with rewetting can buffer negative effects of drought on N status of forage plants and their populations. Here, we compared shoot N status (N concentration, total N uptake and C/N ratio) of four temperate grass species. Particularly, we investigated ecotypes (populations) grown from seeds from four to six European provenances/species after a drought treatment combined with rewetting (10 day harvest delay) versus continuously watered conditions for control. The experimental combination of drought and rewetting significantly increased shoot N concentration (+96%), N uptake (+31%); and decreased C/N ratio (-46%), biomass production (-29%) and C concentration (-1.4%) compared to control. Shoot N status was found to be different between target grass species and also within their populations under drought combined with rewetting treatment. Presumably drought-adapted populations did not perform better than populations from moist sites indicating no evidence of local adaptation. The drought combined with rewetting event could buffer the negative effects of drought. Shoot N status of grasses after drought and rewetting even exceeded control plants. This surprising finding can potentially be explained by higher N uptake, lack of growth dilution effects or delayed plant maturation. Furthermore, within-species shoot N status responses to drought combined with rewetting event were ecotype-specific, hinting at diverse responses of different population. For rangeland management, we recommend that if a drought event occurs during the growing season, harvesting should be delayed beyond a following rain event.

Grass buffers for playas in agricultural landscapes: An annotated bibliography

USGS Publications Warehouse

Melcher, Cynthia P.; Skagen, Susan K.

2005-01-01

References on best management practices (BMPs) for agricultural lands were included because certain BMPs are crucial for informing decisions about buffer design/ effectiveness and overall playa ecology. We also included various papers that increase the spectrum of time over which buffer theories and practices have evolved. An unannotated section lists references that we did not prioritize for annotation and references that may be helpful but were beyond the scope of this document. Finally, we provide notes on conversations we had with scientists, land managers, and other buffer experts whom we consulted, and their contact information. We conclude the bibliography with appendices of common and scientific names of birds and plants and acronyms used in both the bibliography. In the annotations, italicized text signifies our own editorial remarks. Readers should also note that much of the work on buffers has been designed using English units of measure rather than metrics; in most cases, their results have been converted to metrics for publication, explaining the seemingly odd or irregular buffer widths and other parameters reported.

Soil quality indicator responses to row crop, grazed pasture, and agroforestry buffer management

USDA-ARS?s Scientific Manuscript database

Incorporation of trees and establishment of grass buffers within agroecosystems are management practices shown to enhance soil quality. Soil enzyme activities and water stable aggregates (WSA) have been identified as sensitive soil quality indicators to evaluate early responses to soil management. ...

APEX Model Simulation for Row Crop Watersheds with Agroforestry and Grass Buffers

USDA-ARS?s Scientific Manuscript database

Watershed model simulation has become an important tool in studying ways and means to reduce transport of agricultural pollutants. Conducting field experiments to assess buffer influences on water quality are constrained by the large-scale nature of watersheds, high experimental costs, private owner...

Utilizing vegetative environmental buffers to mitigate ammonia and particulate matter emissions from poultry houses

USDA-ARS?s Scientific Manuscript database

Vegetative Environmental Buffers (VEBs) are vegetation designed as a visual screen, which usually consist of trees, shrubs, grass and other potential plants. VEBs are placed around the poultry houses for the purpose of minimizing the air pollutant emissions. The expansion of the poultry industry due...

Nitrous Oxide Emissions from Riparian Forest Buffers, Warm-Season and Cool-Season Grass Filters, and Crop Fields

USDA-ARS?s Scientific Manuscript database

Increasing denitrification rates in riparian buffers may be trading the problem of nonpoint source (NPS) pollution of surface waters for atmospheric deterioration and increased global warming potential because denitrification produces nitrous oxide (N2O), a greenhouse gas also involved in stratosphe...

Gypsum's influence on corn yield and p loss from an eroded southern piedmont soil

USDA-ARS?s Scientific Manuscript database

Gypsum (CaSO4) has been shown to reduce dissolved P in surface water runoff from pastures fertilized with poultry litter (PL). However, limited research has evaluated gypsum’s influence on P loss under row crops. Moreover, can gypsum effectively reduce P loss when applied only to grass buffer strips...

Provisioning of nestling Dickcissels in native warm-season grass field buffers

USGS Publications Warehouse

Mitchell, K.L.; Riffell, Samuel K.; Burger, L. Wes; Vilella, Francisco

2012-01-01

We used video cameras in 2008–2009 to record provisioning activities at Dickcissel (Spiza americana) nests in and around Conservation Reserve Program field buffers in north-central Mississippi, USA. We simultaneously observed foraging flight distances of parents. Provisioning rate (P  =  0.412), biomass (P  =  0.161), and foraging distance (P  =  0.159) did not increase with nestling age. Parents delivered larger items to meet demand associated with older nestlings (P  =  0.010–0.001). This suggests energetic costs of changes in prey selection were less than costs of increasing the number or distance of provisioning trips. Presence of male helpers increased provisioning rate (P < 0.001) but not biomass (P  =  0.992) because males brought smaller prey items (P  =  0.001–0.021). Presence of observers 30 m from the nest reduced provisioning rates (P  =  0.005) and biomass delivered (P  =  0.066). Lack of habitat effects for any aspect of provisioning suggests grass field buffers provided nestling food resources similar to surrounding habitats. Use of continuous video monitoring of nest activity allows well-concealed activities including provisioning and male helping to be directly observed and better quantified.

Watershed scale assessment of the impact of forested riparian zones on stream water quality

Treesearch

J. A. Webber; K. W. J. Williard; M. R. Whiles; M. L. Stone; J. J. Zaczek; D. K. Davie

2003-01-01

Federal and state land management agencies have been promoting forest and grass riparian zones to combat non-point source nutrient and sediment pollution of our nations' waters. The majority of research examining the effectiveness of riparian buffers at reducing nutrient and sediment inputs to streams has been conducted at the field scale. This study took a...

Weed control and persistence of two oxyfluorfen formulations in olive groves under non tillage conditions.

PubMed

Martínez, M J; Farsaoui, K; de Prado, R

2004-01-01

To obtain profitable yields in olive groves, residual preemergence herbicides are applied in October or November before the winter rains, and before the winter annual weeds germinate. Simazine, one of the herbicides most used for weed control in olive groves, has recently been banned. Oxyfluorfen is presented as a good alternative to simazine in olive fields. Experiments were carried out in 2002 and 2003 to evaluate the behaviour of two oxyfluorfen formulations, 2XL and G4F, at 480 g a.i. ha(-1) for three different soil management systems with three replications (1. bare soil; 2. bare soil and grassed buffer strips, chemically controlled and 3. bare soil and grassed buffer strips with controlled mowing; under non tillage conditions in all three cases). The most important species that survived 2XL and G4F treatments was Sagina apetala ARD. Oxyfluorfen residues were evaluated throughout 158 days after the applications. Three soil samples from each plot were collected, mixed and air dried. The herbicide extractions were made with methanol and the residues were analyzed by HPLC. We found no differences between the two formulations, but results showed that recoveries of oxyfluorfen were higher in plots with chemically controlled buffer grassed strips than in the other soil management types.

Sidewalk Landscape Structure and Thermal Conditions for Child and Adult Pedestrians

PubMed Central

Kim, Young-Jae; Lee, Chanam; Kim, Jun-Hyun

2018-01-01

Walking is being promoted for health and transportation purposes across all climatic regions in the US and beyond. Despite this, an uncomfortable microclimate condition along sidewalks is one of the major deterrents of walking, and more empirical research is needed to determine the risks of heat exposure to pedestrians while walking. This study examined the effect of street trees and grass along sidewalks on air temperatures. A series of thermal images were taken at the average heights of adults and children in the US to objectively measure the air temperatures of 10 sidewalk segments in College Station, TX, USA. After controlling the other key physical environmental conditions, sidewalks with more trees or wider grass buffer areas had lower air temperatures than those with less vegetation. Children were exposed to higher temperatures due to the greater exposure or proximity to the pavement surface, which tends to have higher radiant heat. Multivariate regression analysis suggested that the configuration of trees and grass buffers along the sidewalks helped to promote pleasant thermal conditions and reduced the differences in ambient air temperatures measured at child and adult heights. This study suggests that street trees and vegetated ground help reduce the air temperatures, leading to more thermally comfortable environments for both child and adult pedestrians in warm climates. The thermal implications of street landscape require further attention by researchers and policy makers that are interested in promoting outdoor walking. PMID:29346312

Denitrification and N2O emissions in annual croplands, perennial grass buffers, and restored perennial grasslands

USDA-ARS?s Scientific Manuscript database

Inclusion of perennial vegetation filter strips (PFS) in the toeslope of annual cropland watersheds can decrease nitrate (NO3) losses to ground and surface waters. Although PFS are similar to riparian buffers, PFS are a relatively new conservation tool and the processes responsible for NO3 removal f...

Perennial grass and native wildflowers: a synergistic approach to habitat management

USDA-ARS?s Scientific Manuscript database

A total of 19 buffer plots were established on University of Georgia experimental farms and lands near Tifton, GA in 2015. The buffer plots were assigned to a 2 x 2 design of local spatial context and irrigation. For local spatial context, ten plots were located adjacent to woodland (“T”) and ten in...

Phosphorus mitigation during springtime runoff by amendments applied to grassed soil.

PubMed

Uusi-Kämppä, J; Turtola, E; Närvänen, A; Jauhiainen, L; Uusitalo, R

2012-01-01

Permanent grass vegetation on sloping soils is an option to protect fields from erosion, but decaying grass may liberate considerable amounts of dissolved reactive P (DRP) in springtime runoff. We studied the effects of freezing and thawing of grassed soil on surface runoff P concentrations by indoor rainfall simulations and tested whether the peak P concentrations could be reduced by amending the soil with P-binding materials containing Ca or Fe. Forty grass-vegetated soil blocks (surface area 0.045 m, depth 0.07 m) were retrieved from two permanent buffer zones on a clay and loam soil in southwest Finland. Four replicates were amended with either: (i) gypsum from phosphoric acid processing (CaSO × 2HO, 6 t ha), (ii) chalk powder (CaCO, 3.3 t ha), (iii) Fe-gypsum (6 t ha) from TiO processing, or (iv) granulated ferric sulfate (Fe[SO], 0.7 t ha), with four replicates serving as untreated controls. Rainfall (3.3 h × 5 mm h) was applied on presaturated samples set at a slope of 5% and the surface runoff was analyzed for DRP, total dissolved P (TDP), total P (TP), and suspended solids. Rainfall simulation was repeated twice after the samples were frozen. Freezing and thawing of the samples increased the surface runoff DRP concentration of the control treatment from 0.19 to 0.46 mg L, up to 2.6-3.7 mg L, with DRP being the main P form in surface runoff. Compared with the controls, surface runoff from soils amended with Fe compounds had 57 to 80% and 47 to 72% lower concentrations of DRP and TP, respectively, but the gypsum and chalk powder did not affect the P concentrations. Thus, amendments containing Fe might be an option to improve DRP retention in, e.g., buffer zones. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

7 CFR 1410.30 - Signup.

Code of Federal Regulations, 2012 CFR

2012-01-01

... highly under § 1410.31(b) and may include high priority practices such as filter strips, riparian buffers, shelterbelts, field windbreaks, and living snow fences, grass waterways, shallow water areas for wildlife, salt...

7 CFR 1410.30 - Signup.

Code of Federal Regulations, 2010 CFR

2010-01-01

... highly under § 1410.31(b) and may include high priority practices such as filter strips, riparian buffers, shelterbelts, field windbreaks, and living snow fences, grass waterways, shallow water areas for wildlife, salt...

7 CFR 1410.30 - Signup.

Code of Federal Regulations, 2014 CFR

2014-01-01

... highly under § 1410.31(b) and may include high priority practices such as filter strips, riparian buffers, shelterbelts, field windbreaks, and living snow fences, grass waterways, shallow water areas for wildlife, salt...

7 CFR 1410.30 - Signup.

Code of Federal Regulations, 2011 CFR

2011-01-01

... highly under § 1410.31(b) and may include high priority practices such as filter strips, riparian buffers, shelterbelts, field windbreaks, and living snow fences, grass waterways, shallow water areas for wildlife, salt...

7 CFR 1410.30 - Signup.

Code of Federal Regulations, 2013 CFR

2013-01-01

... highly under § 1410.31(b) and may include high priority practices such as filter strips, riparian buffers, shelterbelts, field windbreaks, and living snow fences, grass waterways, shallow water areas for wildlife, salt...

Dynamics and mitigation of six pesticides in a "Wet" forest buffer zone.

PubMed

Passeport, Elodie; Richard, Benjamin; Chaumont, Cédric; Margoum, Christelle; Liger, Lucie; Gril, Jean-Joël; Tournebize, Julien

2014-04-01

Pesticide pollution is one of the main current threats on water quality. This paper presents the potential and functioning principles of a "Wet" forest buffer zone for reducing concentrations and loads of glyphosate, isoproturon, metazachlor, azoxystrobin, epoxiconazole, and cyproconazole. A tracer injection experiment was conducted in the field in a forest buffer zone at Bray (France). A fine time-scale sampling enabled to illustrate that interactions between pesticides and forest buffer substrates (soil and organic-rich litter layer), had a retarding effect on molecule transfer. Low concentrations were observed for all pesticides at the forest buffer outlet thus demonstrating the efficiency of "Wet" forest buffer zone for pesticide dissipation. Pesticide masses injected in the forest buffer inlet directly determined concentration peaks observed at the outlet. Rapid and partially reversible adsorption was likely the major process affecting pesticide transfer for short retention times (a few hours to a few days). Remobilization of metazachlor, isoproturon, desmethylisoproturon, and AMPA was observed when non-contaminated water flows passed through the forest buffer. Our data suggest that pesticide sorption properties alone could not explain the complex reaction mechanisms that affected pesticide transfer in the forest buffer. Nevertheless, the thick layer of organic matter litter on the top of the forest soil was a key parameter, which enhanced partially reversible sorption of pesticide, thus retarded their transfer, decreased concentration peaks, and likely increased degradation of the pesticides. Consequently, to limit pesticide pollution transported by surface water, the use of already existing forest areas as buffer zones should be equally considered as the most commonly implemented grass buffer strips.

Imidacloprid sorption and transport in cropland, grass buffer and riparian buffer soils

USGS Publications Warehouse

Satkowski, Laura E.; Goyne, Keith W.; Anderson, Stephen H.; Lerch, Robert N.; Allen, Craig R.; Snow, Daniel D.

2018-01-01

An understanding of neonicotinoid sorption and transport in soil is critical for determining and mitigating environmental risk associated with the most widely used class of insecticides. The objective of this study was to evaluate mobility and transport of the neonicotinoid imidacloprid (ICD) in soils collected from cropland, grass vegetative buffer strip (VBS), and riparian VBS soils. Soils were collected at six randomly chosen sites within grids that encompassed all three land uses. Single-point equilibrium batch sorption experiments were conducted using radio-labeled (14C) ICD to determine solid–solution partition coefficients (Kd). Column experiments were conducted using soils collected from the three vegetation treatments at one site by packing soil into glass columns. Water flow was characterized by applying Br− as a nonreactive tracer. A single pulse of 14C-ICD was then applied, and ICD leaching was monitored for up to 45 d. Bromide and ICD breakthrough curves for each column were simulated using CXTFIT and HYDRUS-1D models. Sorption results indicated that ICD sorbs more strongly to riparian VBS (Kd = 22.6 L kg−1) than crop (Kd = 11.3 L kg−1) soils. Soil organic C was the strongest predictor of ICD sorption (p < 0.0001). The column transport study found mean peak concentrations of ICD at 5.83, 10.84, and 23.8 pore volumes for crop, grass VBS, and riparian VBS soils, respectively. HYDRUS-1D results indicated that the two-site, one-rate linear reversible model best described results of the breakthrough curves, indicating the complexity of ICD sorption and demonstrating its mobility in soil. Greater sorption and longer retention by the grass and riparian VBS soils than the cropland soil suggests that VBS may be a viable means to mitigate ICD loss from agroecosystems, thereby preventing ICD transport into surface water, groundwater, or drinking water resources.

Bird community response to filter strips in Maryland

USGS Publications Warehouse

Blank, P.J.; Dively, G.P.; Gill, D.E.; Rewa, C.A.

2011-01-01

Filter strips are strips of herbaceous vegetation planted along agricultural field margins adjacent to streams or wetlands and are designed to intercept sediment, nutrients, and agrichemicals. Roughly 16,000 ha of filter strips have been established in Maryland through the United States Department of Agriculture's Conservation Reserve Enhancement Program. Filter strips often represent the only uncultivated herbaceous areas on farmland in Maryland and therefore may be important habitat for early-successional bird species. Most filter strips in Maryland are planted to either native warm-season grasses or cool-season grasses and range in width from 10.7 m to 91.4 m. From 2004 to 2007 we studied the breeding and wintering bird communities in filter strips adjacent to wooded edges and non-buffered field edges and the effect that grass type and width of filter strips had on bird community composition. We used 5 bird community metrics (total bird density, species richness, scrub-shrub bird density, grassland bird density, and total avian conservation value), species-specific densities, nest densities, and nest survival estimates to assess the habitat value of filter strips for birds. Breeding and wintering bird community metrics were greater in filter strips than in non-buffered field edges but did not differ between cool-season and warm-season grass filter strips. Most breeding bird community metrics were negatively related to the percent cover of orchardgrass (Dactylis glomerata) in ???1 yr. Breeding bird density was greater in narrow (60 m) filter strips. Our results suggest that narrow filter strips adjacent to wooded edges can provide habitat for many bird species but that wide filter strips provide better habitat for grassland birds, particularly obligate grassland species. If bird conservation is an objective, avoid planting orchardgrass in filter strips and reduce or eliminate orchardgrass from filter strips through management practices. Copyright ?? 2011 The Wildlife Society.

Use of Fuzzy rainfall-runoff predictions for claypan watersheds with conservation buffers in Northeast Missouri

NASA Astrophysics Data System (ADS)

Anomaa Senaviratne, G. M. M. M.; Udawatta, Ranjith P.; Anderson, Stephen H.; Baffaut, Claire; Thompson, Allen

2014-09-01

Fuzzy rainfall-runoff models are often used to forecast flood or water supply in large catchments and applications at small/field scale agricultural watersheds are limited. The study objectives were to develop, calibrate, and validate a fuzzy rainfall-runoff model using long-term data of three adjacent field scale row crop watersheds (1.65-4.44 ha) with intermittent discharge in the claypan soils of Northeast Missouri. The watersheds were monitored for a six-year calibration period starting 1991 (pre-buffer period). Thereafter, two of them were treated with upland contour grass and agroforestry (tree + grass) buffers (4.5 m wide, 36.5 m apart) to study water quality benefits. The fuzzy system was based on Mamdani method using MATLAB 7.10.0. The model predicted event-based runoff with model performance coefficients of r2 and Nash-Sutcliffe Coefficient (NSC) values greater than 0.65 for calibration and validation. The pre-buffer fuzzy system predicted event-based runoff for 30-50 times larger corn/soybean watersheds with r2 values of 0.82 and 0.68 and NSC values of 0.77 and 0.53, respectively. The runoff predicted by the fuzzy system closely agreed with values predicted by physically-based Agricultural Policy Environmental eXtender model (APEX) for the pre-buffer watersheds. The fuzzy rainfall-runoff model has the potential for runoff predictions at field-scale watersheds with minimum input. It also could up-scale the predictions for large-scale watersheds to evaluate the benefits of conservation practices.

Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study.

PubMed

Radcliffe, Michael J; Lewith, George T; Turner, Richard G; Prescott, Philip; Church, Martin K; Holgate, Stephen T

2003-08-02

To assess the efficacy of enzyme potentiated desensitisation in the treatment of severe summer hay fever poorly controlled by pharmacotherapy. Double blind randomised placebo controlled parallel group study. Hospital in Hampshire. 183 participants aged between 18 and 64 with a history of severe summer hay fever for at least two years; all were skin prick test positive to timothy grass pollen. 90 randomised to active treatment; 93 randomised to placebo. Active treatment: two injections of enzyme potentiated desensitisation, given between eight and 11 weeks apart, each comprising 200 Fishman units of beta glucuronidase, 50 pg 1,3-cyclohexanediol, 50 ng protamine sulphate, and a mixed inhaled allergen extract (pollen mixes for trees, grasses, and weeds; allergenic fungal spores; cat and dog danders; dust and storage mites) in a total volume of 0.05 ml of buffered saline. Placebo: two injections of 0.05 ml buffered saline solution. Proportion of problem-free days; global rhinoconjunctivitis quality of life scores assessed weekly during pollen season. The active treatment group and the placebo group did not differ in the proportion of problem-free days, quality of life scores, symptom severity scores, change in quantitative skin prick provocation threshold, or change in conjunctival provocation threshold. No clinically significant adverse reactions occurred. Enzyme potentiated desensitisation showed no treatment effect in this study.

The impact of inter-annual rainfall variability on African savannas changes with mean rainfall.

PubMed

Synodinos, Alexis D; Tietjen, Britta; Lohmann, Dirk; Jeltsch, Florian

2018-01-21

Savannas are mixed tree-grass ecosystems whose dynamics are predominantly regulated by resource competition and the temporal variability in climatic and environmental factors such as rainfall and fire. Hence, increasing inter-annual rainfall variability due to climate change could have a significant impact on savannas. To investigate this, we used an ecohydrological model of stochastic differential equations and simulated African savanna dynamics along a gradient of mean annual rainfall (520-780 mm/year) for a range of inter-annual rainfall variabilities. Our simulations produced alternative states of grassland and savanna across the mean rainfall gradient. Increasing inter-annual variability had a negative effect on the savanna state under dry conditions (520 mm/year), and a positive effect under moister conditions (580-780 mm/year). The former resulted from the net negative effect of dry and wet extremes on trees. In semi-arid conditions (520 mm/year), dry extremes caused a loss of tree cover, which could not be recovered during wet extremes because of strong resource competition and the increased frequency of fires. At high mean rainfall (780 mm/year), increased variability enhanced savanna resilience. Here, resources were no longer limiting and the slow tree dynamics buffered against variability by maintaining a stable population during 'dry' extremes, providing the basis for growth during wet extremes. Simultaneously, high rainfall years had a weak marginal benefit on grass cover due to density-regulation and grazing. Our results suggest that the effects of the slow tree and fast grass dynamics on tree-grass interactions will become a major determinant of the savanna vegetation composition with increasing rainfall variability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-structural carbohydrate partitioning in grass stems: a target to increase yield stability, stress tolerance, and biofuel production.

PubMed

Slewinski, Thomas L

2012-08-01

A dramatic change in agricultural crops is needed in order to keep pace with the demands of an increasing human population, exponential need for renewable fuels, and uncertain climatic changes. Grasses make up the vast majority of agricultural commodities. How these grasses capture, transport, and store carbohydrates underpins all aspects of crop productivity. Sink-source dynamics within the plant direct how much, where, and when carbohydrates are allocated, as well as determine the harvestable tissue. Carbohydrate partitioning can limit the yield capacity of these plants, thus offering a potential target for crop improvement. Grasses have the ability to buffer this sink-source interaction by transiently storing carbohydrates in stem tissue when production from the source is greater than whole-plant demand. These reserves improve yield stability in grain crops by providing an alternative source when photosynthetic capacity is reduced during the later phases of grain filling, or during periods of environmental and biotic stresses. Domesticated grasses such as sugarcane and sweet sorghum have undergone selection for high accumulation of stem carbohydrates, which serve as the primary sources of sugars for human and animal consumption, as well as ethanol production for fuel. With the enormous expectations placed on agricultural production in the near future, research into carbohydrate partitioning in grasses is essential for maintaining and increasing yields in grass crops. This review highlights the current knowledge of non-structural carbohydrate dynamics in grass stems and discusses the impacts of stem reserves in essential agronomic grasses.

Estimating the financial risks of Andropogon gayanus to greenhouse gas abatement projects in northern Australia

NASA Astrophysics Data System (ADS)

Adams, Vanessa M.; Setterfield, Samantha A.

2013-06-01

Financial mechanisms such as offsets are one strategy to abate greenhouse gas emissions, and the carbon market is expanding with a growing demand for offset products. However, in the case of carbon offsets, if the carbon is released due to intentional or unintentional reversal through environmental events such as fire, the financial liability to replace lost offsets will likely fall on the provider. This liability may have implications for future participation in programmes, but common strategies such as buffer pool and insurance products can be used to minimize this liability. In order for these strategies to be effective, an understanding of the spatial and temporal distributions of expected reversals is needed. We use the case study of savanna burning, an approved greenhouse gas abatement methodology under the Carbon Farming Initiative in Australia, to examine potential risks to carbon markets in northern Australia and quantify the financial risks. We focus our analysis on the threat of Andropogon gayanus (gamba grass) to savanna burning due to its documented impacts of increased fuel loads and altered fire regimes. We assess the spatial and financial extent to which gamba grass poses a risk to savanna burning programmes in northern Australia. We find that 75% of the eligible area for savanna burning is spatially coincident with the high suitability range for gamba grass. Our analysis demonstrates that the presence of gamba grass seriously impacts the financial viability of savanna burning projects. For example, in order to recuperate the annual costs of controlling 1 ha of gamba grass infestation, 290 ha of land must be enrolled in annual carbon abatement credits. Our results show an immediate need to contain gamba grass to its current extent to avoid future spread into large expanses of land, which are currently profitable for savanna burning.

7 CFR 1410.6 - Eligible land.

Code of Federal Regulations, 2014 CFR

2014-01-01

... riparian buffer only if, as determined by CCC, it: (A) Is located adjacent to permanent stream corridors excluding corridors that are considered gullies or sod waterways; and (B) Is capable, when permanent grass... vegetation suitable for wetland restoration or wildlife habitat, as determined appropriate by the CCC, of...

7 CFR 1410.6 - Eligible land.

Code of Federal Regulations, 2012 CFR

2012-01-01

... riparian buffer only if, as determined by CCC, it: (A) Is located adjacent to permanent stream corridors excluding corridors that are considered gullies or sod waterways; and (B) Is capable, when permanent grass... vegetation suitable for wetland restoration or wildlife habitat, as determined appropriate by the CCC, of...

7 CFR 1410.6 - Eligible land.

Code of Federal Regulations, 2013 CFR

2013-01-01

... riparian buffer only if, as determined by CCC, it: (A) Is located adjacent to permanent stream corridors excluding corridors that are considered gullies or sod waterways; and (B) Is capable, when permanent grass... vegetation suitable for wetland restoration or wildlife habitat, as determined appropriate by the CCC, of...

Riparian Sediment Delivery Ratio: Stiff Diagrams and Artifical Neural Networks

EPA Science Inventory

Various methods are used to estimate sediment transport through riparian buffers and grass jilters with the sediment delivery ratio having been the most widely applied. The U.S. Forest Service developed a sediment delivery ratio using the stiff diagram and a logistic curve to int...

Modelling the effectiveness of grass buffer strips in managing muddy floods under a changing climate

NASA Astrophysics Data System (ADS)

Mullan, Donal; Vandaele, Karel; Boardman, John; Meneely, John; Crossley, Laura H.

2016-10-01

Muddy floods occur when rainfall generates runoff on agricultural land, detaching and transporting sediment into the surrounding natural and built environment. In the Belgian Loess Belt, muddy floods occur regularly and lead to considerable economic costs associated with damage to property and infrastructure. Mitigation measures designed to manage the problem have been tested in a pilot area within Flanders and were found to be cost-effective within three years. This study assesses whether these mitigation measures will remain effective under a changing climate. To test this, the Water Erosion Prediction Project (WEPP) model was used to examine muddy flooding diagnostics (precipitation, runoff, soil loss and sediment yield) for a case study hillslope in Flanders where grass buffer strips are currently used as a mitigation measure. The model was run for present day conditions and then under 33 future site-specific climate scenarios. These future scenarios were generated from three earth system models driven by four representative concentration pathways and downscaled using quantile mapping and the weather generator CLIGEN. Results reveal that under the majority of future scenarios, muddy flooding diagnostics are projected to increase, mostly as a consequence of large scale precipitation events rather than mean changes. The magnitude of muddy flood events for a given return period is also generally projected to increase. These findings indicate that present day mitigation measures may have a reduced capacity to manage muddy flooding given the changes imposed by a warming climate with an enhanced hydrological cycle. Revisions to the design of existing mitigation measures within existing policy frameworks are considered the most effective way to account for the impacts of climate change in future mitigation planning.

Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study

PubMed Central

Radcliffe, Michael J; Lewith, George T; Turner, Richard G; Prescott, Philip; Church, Martin K; Holgate, Stephen T

2003-01-01

Objective To assess the efficacy of enzyme potentiated desensitisation in the treatment of severe summer hay fever poorly controlled by pharmacotherapy. Design Double blind randomised placebo controlled parallel group study. Setting Hospital in Hampshire. Participants 183 participants aged between 18 and 64 with a history of severe summer hay fever for at least two years; all were skin prick test positive to timothy grass pollen. 90 randomised to active treatment; 93 randomised to placebo. Interventions Active treatment: two injections of enzyme potentiated desensitisation, given between eight and 11 weeks apart, each comprising 200 Fishman units of β glucuronidase, 50 pg 1,3-cyclohexanediol, 50 ng protamine sulphate, and a mixed inhaled allergen extract (pollen mixes for trees, grasses, and weeds; allergenic fungal spores; cat and dog danders; dust and storage mites) in a total volume of 0.05 ml of buffered saline. Placebo: two injections of 0.05 ml buffered saline solution. Main outcome measures Proportion of problem-free days; global rhinoconjunctivitis quality of life scores assessed weekly during pollen season. Results The active treatment group and the placebo group did not differ in the proportion of problem-free days, quality of life scores, symptom severity scores, change in quantitative skin prick provocation threshold, or change in conjunctival provocation threshold. No clinically significant adverse reactions occurred. Conclusions Enzyme potentiated desensitisation showed no treatment effect in this study. PMID:12896934

Assessment and placement of living snow fences to reduce highway maintenance costs and improve safety (living snow fences).

DOT National Transportation Integrated Search

2015-05-01

Living snow fences (LSF) are designed plantings of trees and/or shrubs and native grasses along highways, roads : and ditches that create a vegetative buffer that traps and controls blowing and drifting snow. These strategically : placed fences have ...

Plant Growth and Phosphorus Uptake of Three Riparian Grass Species

USDA-ARS?s Scientific Manuscript database

Riparian buffers can significantly reduce sediment-bound phosphorus (P) entering surface water, but control of dissolved P inputs is more challenging. Because plant roots remove P from soil solution, it follows that plant uptake will reduce dissolved P losses. We evaluated P uptake of smooth bromegr...

Agroforestry practices, runoff, and nutrient loss: a paired watershed comparison.

PubMed

Udawatta, Ranjith P; Krstansky, J John; Henderson, Gray S; Garrett, Harold E

2002-01-01

A paired watershed study consisting of agroforestry (trees plus grass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation was used to examine treatment effects on runoff, sediment, and nutrient losses. During the (1991-1997) calibration and subsequent three-year treatment periods, runoff was measured in 0.91- and 1.37-m H-flumes with bubbler flow meters. Composite samples were analyzed for sediment, total phosphorus (TP), total nitrogen (TN), nitrate, and ammonium. Calibration equations developed to predict runoff, sediment, and nutrients losses explained 66 to 97% of the variability between treatment watersheds. The contour strip and agroforestry treatments reduced runoff by 10 and 1% during the treatment period. In both treatments, most runoff reductions occurred in the second and third years after treatment establishment. The contour strip treatment reduced erosion by 19% in 1999, while erosion in the agroforestry treatment exceeded the predicted loss. Treatments reduced TP loss by 8 and 17% on contour strip and agroforestry watersheds. Treatments did not result in reductions in TN during the first two years of the treatment period. The contour strip and agroforestry treatments reduced TN loss by 21 and 20%, respectively, during a large precipitation event in the third year. During the third year of treatments, nitrate N loss was reduced 24 and 37% by contour strip and agroforestry treatments. Contour strip and agroforestry management practices effectively reduced nonpoint-source pollution in runoff from a corn-soybean rotation in the clay pan soils of northeastern Missouri.

Co-digestion of manure with grass silage and pulp and paper mill sludge using nutrient additions.

PubMed

Hagelqvist, Alina; Granström, Karin

2016-08-01

There is an increasing worldwide demand for biogas. Anaerobic co-digestion involves the treatment of different substrates with the aim of improving the production of biogas and the stability of the process. This study evaluates how methane production is affected by the co-digestion of pig and dairy manure with grass silage and pulp and paper mill sludge and assesses whether methane production is affected by factors other than nutrient deficiency, low buffering capacity, inadequate dilution, and an insufficient activity and amount of microorganism culture. Anaerobic digestion was performed in batch reactors under mesophilic conditions for 20 days. The season of grass silage and manure collection proved to be an important factor affecting methane production. Spring grass silage produced a maximum of 250 mL/VSadded and spring manure 150 mL/VSadded, whereas autumn grass silage produced at most 140 ml/VSadded and autumn manure 45 mL/VSadded. The pulp mill sludge used is comprised of both primary and secondary sludge and produced at most 50 mL/VSadded regardless of season; this substrate benefitted most from co-digestion.

Climate variability has a stabilizing effect on the coexistence of prairie grasses

PubMed Central

Adler, Peter B.; HilleRisLambers, Janneke; Kyriakidis, Phaedon C.; Guan, Qingfeng; Levine, Jonathan M.

2006-01-01

How expected increases in climate variability will affect species diversity depends on the role of such variability in regulating the coexistence of competing species. Despite theory linking temporal environmental fluctuations with the maintenance of diversity, the importance of climate variability for stabilizing coexistence remains unknown because of a lack of appropriate long-term observations. Here, we analyze three decades of demographic data from a Kansas prairie to demonstrate that interannual climate variability promotes the coexistence of three common grass species. Specifically, we show that (i) the dynamics of the three species satisfy all requirements of “storage effect” theory based on recruitment variability with overlapping generations, (ii) climate variables are correlated with interannual variation in species performance, and (iii) temporal variability increases low-density growth rates, buffering these species against competitive exclusion. Given that environmental fluctuations are ubiquitous in natural systems, our results suggest that coexistence based on the storage effect may be underappreciated and could provide an important alternative to recent neutral theories of diversity. Field evidence for positive effects of variability on coexistence also emphasizes the need to consider changes in both climate means and variances when forecasting the effects of global change on species diversity. PMID:16908862

Effects of buffers on milk fatty acids and mammary arteriovenous differences in dairy cows fed Ca salts of fatty acids.

PubMed

Thivierge, M C; Chouinard, P Y; Lévesque, J; Girard, V; Seoane, J R; Brisson, G J

1998-07-01

Ten Holstein cows in early lactation were used in a replicated 5 x 5 Latin square design to study the effects of MgO and three buffers added to diets containing Ca salts of canola oil fatty acids. Treatments were 1) control (basal diet; no buffer). 2) 1.1% NaHCO3 plus 1.1% KHCO3, 3) 1.9% NaHCO3, 4) 0.5% MgO, and 5) 2.0% Na sesquicarbonate (percentage of dry matter). The control diet contained 53% grass silage, 43% concentrate, and 4% Ca salts. Body weight, intake, milk yield, and percentages of milk fat, protein, and lactose were unaffected by treatments. Buffers and MgO tended to increase triacylglycerol extraction by the mammary gland and changed the proportions of some fatty acids in milk. Arterial concentrations of acetate and triacylglycerol were correlated with their respective arteriovenous differences. Extraction by the mammary gland was high for acetate (approximately equal to 58.2%), triacylglycerol (approximately equal to 47.3%) propionate (approximately equal to 34.6%), and glucose (approximately equal to 24.3%). Extraction of free fatty acids, phospholipids, or cholesterol was negligible. Mammary triacylglycerol arteriovenous difference tended to be higher than when MgO was fed than when NaHCO3 was fed. Sodium sesquicarbonate, NaHCO3, and the blend of bicarbonate buffers increased C18:2 in milk fat when compared with the control treatment. The concentration of C18:2 in milk fat decreased when MgO was fed, but the ratio of cis-C18:1 to trans-C18:1 increased compared with effects of dietary NaHCO3. Medium-chain fatty acids in milk fat tended to be higher than Na sesquicarbonate than with NaHCO3. Buffers and MgO modified the profiles of fatty acids in milk.

Isolation and partial purification of cadmium-binding protein from roots of the grass Agrostis gigantea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rauser, W.E.

1984-04-01

A cadmium-binding protein was isolated from roots of the grass Agrostis gigantea Roth. Heat-stable proteins were chromatographed on the anion exchanger QAE-Sephadex A-25. The major cadmium fraction was purified further by gel filtration of Sephadex G-75 in 1 molar KCI buffer. The resulting protein preparation was light brown, had an apparent molecular weight of 3700, contained 29% cysteine and close to 4 gram atoms cadmium/mole. The cadmium:cysteine ratio was l:2.7. Spectroscopic measurments indicated cadmium-thiolate coordination. The roots produced the metallothionein-like protein when they were exposed to cadmium for 7 days.

Responses to riparian restoration in the Spring Creek watershed, Central Pennsylvania

USGS Publications Warehouse

Carline, R.F.; Walsh, M.C.

2007-01-01

Riparian treatments, consisting of 3- to 4-m buffer strips, stream bank stabilization, and rock-lined stream crossings, were installed in two streams with livestock grazing to reduce sediment loading and stream bank erosion. Cedar Run and Slab Cabin Run, the treatment streams, and Spring Creek, an adjacent reference stream without riparian grazing, were monitored prior to (1991-1992) and 3-5 years after (2001-2003) riparian buffer installation to assess channel morphology, stream substrate composition, suspended sediments, and macroinvertebrate communities. Few changes were found in channel widths and depths, but channel-structuring flow events were rare in the drought period after restoration. Stream bank vegetation increased from 50% or less to 100% in nearly all formerly grazed riparian buffers. The proportion of fine sediments in stream substrates decreased in Cedar Run but not in Slab Cabin Run. After riparian treatments, suspended sediments during base flow and storm flow decreased 47-87% in both streams. Macroinvertebrate diversity did not improve after restoration in either treated stream. Relative to Spring Creek, macroinvertebrate densities increased in both treated streams by the end of the posttreatment sampling period. Despite drought conditions that may have altered physical and biological effects of riparian treatments, goals of the riparian restoration to minimize erosion and sedimentation were met. A relatively narrow grass buffer along 2.4 km of each stream was effective in improving water quality, stream substrates, and some biological metrics. ?? 2007 Society for Ecological Restoration International.

Effect of vegetated filter strips on transport and deposition rates of Escherichia coli in overland flow in the eastern escarpments of the Mau Forest, Njoro River Watershed, Kenya

PubMed Central

Onyando, J. O.; Moturi, W. N.; Muia, A. W.; Ombui, P.; Shivoga, W. A.; Roegner, A. F.

2016-01-01

The fate and transport of Escherichia coli (E. coli) in lotic waters through vegetated filter strips (VFSs) was evaluated in a field model pasture, utilizing VFSMOD Windows along with direct pathogen testing. This study assessed effects of VFS on transport and deposition rates of E. coli in lotic overland flow waters. The VFS measured 44 m long by 40 m wide, covering an area of 1584 m2 and land slope of 15 %. Cowpat was applied onto the model pasture and washed by overland flow into the VFS. The 4-methylumbelliferyl β-D-glucuronide substrate confirmed the identity of E. coli prior to cowpat application and after isolating them from soil using centrifugation and membrane filtration techniques. Napier grass root system recorded the highest recovery rates of E. coli at 99.9 % along the length of VFS III. This efficiency reduced significantly (p < 0.05; df = 29) to 95 % in Kikuyu grass and 75 % in Couch grass–Buffer grass. The data demonstrated similarity in transport of manure-borne E. coli and organic carbon (OC) through all the simulated VFS. These results indicated that OC could be used as a true natural tracer of manure-borne E. coli, a pollution indicator organism of lentic and lotic surface waters provided the OC release kinetics from cowpat were similar to that of E. coli kinetics. Thus, efficient filtering to reduce E. coli concentrations and load in overland flows requires managing combined grass species, agro-pastoral systems models and dispersed or preferential flows to enhance surface water quality standards. PMID:28393102

Sulfamethazine Sorption to Soil: Vegetative Management, pH, and Dissolved Organic Matter Effects.

PubMed

Chu, Bei; Goyne, Keith W; Anderson, Stephen H; Lin, Chung-Ho; Lerch, Robert N

2013-01-01

Elucidating veterinary antibiotic interactions with soil is important for assessing and mitigating possible environmental hazards. The objectives of this study were to investigate the effects of vegetative management, soil properties, and >1000 Da dissolved organic matter (DOM) on sulfamethazine (SMZ) behavior in soil. Sorption experiments were performed over a range of SMZ concentrations (2.5-50 μmol L) using samples from three soils (Armstrong, Huntington, and Menfro), each planted to one of three vegetation treatments: agroforestry buffers strips (ABS), grass buffer strips (GBS), and row crops (RC). Our results show that SMZ sorption isotherms are well fitted by the Freundlich isotherm model (log = 0.44-0.93; Freundlich nonlinearity parameter = 0.59-0.79). Further investigation of solid-to-solution distribution coefficients () demonstrated that vegetative management significantly ( < 0.05) influences SMZ sorption (ABS > GBS > RC). Multiple linear regression analyses indicated that organic carbon (OC) content, pH, and initial SMZ concentration were important properties controlling SMZ sorption. Study of the two most contrasting soils in our sample set revealed that increasing solution pH (pH 6.0-7.5) reduced SMZ sorption to the Armstrong GBS soil, but little pH effect was observed for the Huntington GBS soil containing 50% kaolinite in the clay fraction. The presence of DOM (150 mg L OC) had little significant effect on the Freundlich nonlinearity parameter; however, DOM slightly reduced SMZ values overall. Our results support the use of vegetative buffers to mitigate veterinary antibiotic loss from agroecosystems, provide guidance for properly managing vegetative buffer strips to increase SMZ sorption, and enhance understanding of SMZ sorption to soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

EnviroAtlas - Paterson, NJ - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the Atlas Area. EnviroAtlas defines vegetated buffer for this community as trees and forest and grass and herbaceous. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Long-term assessment of runoff and sediment transport from grass and agroforestry buffers in corn/soybean watersheds using APEX

USDA-ARS?s Scientific Manuscript database

Existence of a claypan layer in soils at depths ranging from 4 to 37 cm restricts water movement and has contributed significantly to high rates of runoff, sediment transport, and other non-point source loadings from croplands in watersheds. The deposition of these pollutants in rivers, streams and...

Using satellite vegetation and compound topographic indices to map highly erodible cropland buffers for cellulosic biofuel crop developments in eastern Nebraska, USA

USGS Publications Warehouse

Gu, Yingxin; Wylie, Bruce K.

2015-01-01

Cultivating annual row crops in high topographic relief waterway buffers has negative environmental effects and can be environmentally unsustainable. Growing perennial grasses such as switchgrass (Panicum virgatum L.) for biomass (e.g., cellulosic biofuel feedstocks) instead of annual row crops in these high relief waterway buffers can improve local environmental conditions (e.g., reduce soil erosion and improve water quality through lower use of fertilizers and pesticides) and ecosystem services (e.g., minimize drought and flood impacts on production; improve wildlife habitat, plant vigor, and nitrogen retention due to post-senescence harvest for cellulosic biofuels; and serve as carbon sinks). The main objectives of this study are to: (1) identify cropland areas with high topographic relief (high runoff potentials) and high switchgrass productivity potential in eastern Nebraska that may be suitable for growing switchgrass, and (2) estimate the total switchgrass production gain from the potential biofuel areas. Results indicate that about 140,000 hectares of waterway buffers in eastern Nebraska are suitable for switchgrass development and the total annual estimated switchgrass biomass production for these suitable areas is approximately 1.2 million metric tons. The resulting map delineates high topographic relief croplands and provides useful information to land managers and biofuel plant investors to make optimal land use decisions regarding biofuel crop development and ecosystem service optimization in eastern Nebraska.

Use of black soldier fly larvae (Hermetia illucens) to substitute soybean meal in ruminant diet: An in vitro rumen fermentation study

PubMed Central

Jayanegara, Anuraga; Novandri, Briliannanda; Yantina, Nover; Ridla, Muhammad

2017-01-01

Aim: This experiment aimed to evaluate substitution of soybean meal (SBM) by black soldier fly (BSF) larvae meal in a napier grass diet as performed by an in vitro rumen fermentation system. Materials and Methods: Samples of napier grass, SBM, and BSF larvae age 1 week (BSF1) and 2 weeks (BSF2) were arranged according to the following dietary treatments (dry matter [DM] basis): T1, 100% napier grass; T2, 60% napier grass + 40% SBM; T3, 60% napier grass + 40% BSF1; T4, 60% napier grass + 40% BSF2; T5, 60% napier grass + 20% SBM + 20% BSF1; and T6, 60% napier grass + 20% SBM + 20% BSF2. The samples were determined for their chemical composition and were incubated in vitro using buffered rumen fluid for 48 h at 39°C. In vitro incubation was carried out in three runs and represented by two incubation bottles per run. Results: Supplementation of BSF, both BSF1 and BSF2, increased ether extract, neutral- and acid-detergent insoluble crude protein contents of T3-T6 diets. The T3 or T4 diet resulted in lower ruminal ammonia concentration, in vitro DM digestibility, and in vitro organic matter (OM) digestibility as compared to those in T2 (p<0.05). Diet supplemented with BSF produced lower methane emission in comparison to that of supplemented with SBM (p<0.05). Diet containing BSF2 produced lower methane and methane per digestible OM than that containing BSF1 (p<0.05). Conclusion: Substitution of SBM by BSF in ruminant diet results in a lower nutritional value in vitro but with an advantage of lowering ruminal methane emission. PMID:29391684

EnviroAtlas - New York, NY - One Meter Resolution Urban Land Cover Data (2008)

EPA Pesticide Factsheets

The New York, NY EnviroAtlas Meter-scale Urban Land Cover (MULC) Data were generated by the University of Vermont Spatial Analysis Laboratory (SAL) under the direction of Jarlath O'Neil-Dunne as part of the United States Forest Service Urban Tree Canopy (UTC) assessment program. Seven classes were mapped using LiDAR and high resolution orthophotography: Tree Canopy, Grass/Shrub, Bare Soil, Water, Buildings, Roads/Railroads, and Other Paved Surfaces. These data were subsequently merged to fit with the EPA classification. The SAL project covered the five boroughs within the NYC city limits. However the EPA study area encompassed that area plus a 1 kilometer buffer. Additional land cover for the buffer area was generated from United States Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP) four band (red, green, blue, and near infrared) aerial photography at 1 m spatial resolution from July, 2011 and LiDAR from 2010. Six land cover classes were mapped: water, impervious surfaces, soil and barren land, trees, grass-herbaceous non-woody vegetation, and agriculture. An accuracy assessment of 600 completely random and 55 stratified random photo interpreted reference points yielded an overall User's fuzzy accuracy of 87 percent. The area mapped is the US Census Bureau's 2010 Urban Statistical Area for New York City plus a 1 km buffer. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAt

Activation of inoculum microorganism from dairy cattle feces

NASA Astrophysics Data System (ADS)

Ayuningtyas, Widya D.; Ridwan, Roni; Joni, I. M.; Marlina, E. T.; Harlia, Ellin

2018-02-01

Coal produces Coal Bed Methane (CBM) which is formed both biogenically and thermogenically. Lignite is not utilized optimally because it has low heat content and productivity time limit that decreases CBM production. In order to utilize lignite waste, adding inoculum consortium microorganism from dairy cattle waste as starter for biogas process can be a solution. This study aimed to produce inoculum consortium microorganism as biogas starter from dairy cattle feces through in vitro activation process by Theoudorou modification method. The research used complete randomized design with 3 replications. The treatments were blank (R0), 100% concentrate (R1), 70% concentrate+30% grass (R2), 70% grass+30% concentrate (R3) and 100% grass (R4). All treatments were added by buffer solution and feces with ratio of 2:1 into 100 ml serum injection bottle with anaerobic conditions. The parameters observed were gas production, pH and gas kinetics (orskov's equation) for 2, 4, 6, 8, 10, 12, 24 and 48 hours. The results showed that the treatment had significant effect (P <0.05) on the observed parameters. The highest total gas production was for R2 and R3 treatments with total production of 91.17 ml and 101.17 ml, pH (6.62 and 6.57), maximum gas production (94.03 and 97.62 ml), speed of gas production (0.066 and 0.084 ml/hour). There is not a significant difference for both the treatments. The source of inoculum consortium microorganisms for biogas starter selected based on the observed parameters and potential availability of proteolytic and fibrocytic microorganisms is R2 (70% concentrate +30% grass).

Assessing benefits and risk of using flue gas desulfurized gypsum (FGDG) as soil amendment in a Coastal Plain soil

USDA-ARS?s Scientific Manuscript database

The influence of FGDG and grass buffers on runoff water quality and corn production following poultry litter (PL) application is being evaluated as part of a regional USDA-ARS project (Auburn-AL, Oxford-MS, and Tifton-GA). Treatments at Tifton were laid out in a randomized complete block design wit...

ArcAPEX modeling of optimum widths and placement of grass and agroforestry buffers to reduce runoff and sediment transport in claypan watersheds

USDA-ARS?s Scientific Manuscript database

Existence of a claypan layer in soils at depths ranging from 4 to 37 cm restricts vertical water movement and has contributed significantly to high rates of runoff, sediment transport, and other non-point source loadings from croplands in watersheds. The deposition of these pollutants in rivers, st...

Comparison of fractionation methods for nitrogen and starch in maize and grass silages.

PubMed

Ali, M; de Jonge, L H; Cone, J W; van Duinkerken, G; Blok, M C; Bruinenberg, M H; Hendriks, W H

2016-06-01

In in situ nylon bag technique, many feed evaluation systems use a washing machine method (WMM) to determine the washout (W) fraction and to wash the rumen incubated nylon bags. As this method has some disadvantages, an alternate modified method (MM) was recently introduced. The aim of this study was to determine and compare the W and non-washout (D+U) fractions of nitrogen (N) and/or starch of maize and grass silages, using the WMM and the MM. Ninety-nine maize silage and 99 grass silage samples were selected with a broad range in chemical composition. The results showed a large range in the W, soluble (S) and D+U fractions of N of maize and grass silages and the W, insoluble washout (W-S) and D+U fractions of starch of maize silages, determined by both methods, due to variation in their chemical composition. The values for N fractions of maize and grass silages obtained with both methods were found different (p < 0.001). Large differences (p < 0.001) were found in the D+U fraction of starch of maize silages which might be due to different methodological approaches, such as different rinsing procedures (washing vs. shaking), duration of rinsing (40 min vs. 60 min) and different solvents (water vs. buffer solution). The large differences (p < 0.001) in the W-S and D+U fractions of starch determined with both methods can led to different predicted values for the effective rumen starch degradability. In conclusion, the MM with one recommended shaking procedure, performed under identical and controlled experimental conditions, can give more reliable results compared to the WMM, using different washing programs and procedures. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

EnviroAtlas - Austin, TX - 15m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. Vegetated cover is defined as Trees & Forest and Grass & Herbaceous. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

EnviroAtlas - Des Moines, IA - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. Vegetated cover is defined as Trees & Forest and Grass & Herbaceous. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://enviroatlas.epa.gov/EnviroAtlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets)

EnviroAtlas - New York, NY - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest and Grass & Herbaceous. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets)

EnviroAtlas - Austin, TX - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. Vegetated cover is defined as Trees & Forest and Grass & Herbaceous. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

EnviroAtlas - Memphis, TN - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. Vegetated cover is defined as Trees & Forest, Grass & Herbaceous, Woody Wetlands, and Emergent Wetlands. There is a potential for decreased water quality in areas where the riparian buffer is less forested. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

EnviroAtlas - Cleveland, OH - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest, Grass & Herbaceous, Woody Wetlands, and Emergent Wetlands. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas ) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets)

The Role of Legacy Effects and Reactive Amendments on Phosphorus Retention Within Riparian Zones

NASA Astrophysics Data System (ADS)

Surridge, B.; Habibiandehkordi, R.; Quinton, J.

2014-12-01

Undisturbed riparian zones, including river floodplains and field buffer strips, can significantly reduce phosphorus (P) export associated with agricultural production. However, riparian zones are frequently disturbed, including through conversion to agricultural land. Restoring disturbed riparian zones is promoted widely within agri-environment schemes. However, restoration presents significant challenges, two of which are considered in this paper: understanding the impacts of restoration on legacy P within riparian zone soils; and maximising the efficacy of riparian zones for removal of all P fractions, including the more immediately bioavailable soluble P fractions. Firstly, we examine changes in porewater soluble P concentration following re-wetting of a river floodplain in Norfolk, UK, using laboratory mesocosms and in-situ field monitoring. Substantial release of P from sediment to porewater was observed following re-wetting (porewater soluble P concentration exceeded 6.5 mg P L-1), probably associated with reductive-dissolution of iron-bound P within floodplain sediments. Export of soluble P from porewater into adjacent receiving waters was observed following both natural hydrological events and management of the hydrological regime within the floodplain. Secondly, we examine how retention of soluble P with grass buffer strips can be enhanced through application of reactive industrial by-products, focussing on ochre and aluminium-based water treatment residuals. Application of these by-products to buffer strips increased removal of soluble P from surface runoff by over 50% compared to non-amended buffer strips. The long-term effectiveness of reactive amendments is also considered, using repeated runoff events under field conditions. Taken together, the research offers new insights into riparian zone P biogeochemistry within agricultural landscapes.

Pollution Swapping in Agricultural Systems: deciding between mitigation measures with conflicting outcomes

NASA Astrophysics Data System (ADS)

Quinton, John; Stevens, Carly

2010-05-01

Pollution swapping occurs when a mitigation option introduced to reduce one pollutant results in an increase in a different pollutant. Although the concept of pollution swapping is widely understood it has received little attention in research and policy design. This study investigated diffuse pollution mitigation options applied in combinable crop systems. They are: cover crops, residue management, no-tillage, riparian buffer zones, contour grass strips and constructed wetlands. A wide range of water and atmospheric pollutants were considered, including nitrogen, phosphorus, carbon and sulphur. It is clear from this investigation that there is no single mitigation option that will reduce all pollutants and in this poster we consider how choices may be made between mitigation measures which may have a positive effect on one pollutant but a negative effect on another.

EnviroAtlas - Minneapolis/St. Paul, MN - 51m Riparian Buffer Vegetated Cover

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees and Forest, Grass and Herbaceous, Woody Wetlands, and Emergent Wetlands. There is a potential for decreased water quality in areas where the riparian buffer is less vegetated. The displayed line represents the center of the analyzed riparian buffer. The water bodies analyzed include hydrologically connected streams, rivers, connectors, reservoirs, lakes/ponds, ice masses, washes, locks, and rapids within the EnviroAtlas community area. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

Emission reduction by multipurpose buffer strips on arable fields.

PubMed

Sloots, K; van der Vlies, A W

2007-01-01

In the area managed by Hollandse Delta, agriculture is under great pressure and the social awareness of the agricultural sector is increasing steadily. In recent years, a stand-still has been observed in water quality, in terms of agrochemicals, and concentrations even exceed the standard. To improve the waterquality a multi-purpose Field Margin Regulation was drafted for the Hoeksche Waard island in 2005. The regulation prescribes a crop-free strip, 3.5 m wide, alongside wet drainage ditches. The strip must be sown with mixtures of grasses, flowers or herbs. No crop protection chemicals or fertilizer may be used on the strips. A total length of approximately 200 km of buffer strip has now been laid. Besides reducing emissions, the buffer strips also stimulate natural pest control methods and encourage local tourism. Finally, the strips should lead to an improvement in the farmers' image. The regulation has proved to be successful. The buffer strips boosted both local tourism and the image of the agricultural sector. Above all, the strips provided a natural shield for emission to surface water, which will lead to an improvement of the water quality and raise the farmers' awareness of water quality and the environment.

EnviroAtlas - New York, NY - One Meter Resolution Urban Land Cover Data (2008) Web Service

EPA Pesticide Factsheets

This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas ). The New York, NY EnviroAtlas Meter-scale Urban Land Cover (MULC) Data were generated by the University of Vermont Spatial Analysis Laboratory (SAL) under the direction of Jarlath O'Neil-Dunne as part of the United States Forest Service Urban Tree Canopy (UTC) assessment program. Seven classes were mapped using LiDAR and high resolution orthophotography: Tree Canopy, Grass/Shrub, Bare Soil, Water, Buildings, Roads/Railroads, and Other Paved Surfaces. These data were subsequently merged to fit with the EPA classification. The SAL project covered the five boroughs within the NYC city limits. However the EPA study area encompassed that area plus a 1 kilometer buffer. Additional land cover for the buffer area was generated from United States Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP) four band (red, green, blue, and near infrared) aerial photography at 1 m spatial resolution from July, 2011 and LiDAR from 2010. Six land cover classes were mapped: water, impervious surfaces, soil and barren land, trees, grass-herbaceous non-woody vegetation, and agriculture. An accuracy assessment of 600 completely random and 55 stratified random photo interpreted reference points yielded an overall User's fuzzy accuracy of 87 percent. The area mapped is the US Census Bureau's 2010 Urban Statistical Area for New Yor

Separation of dietary omega-3 and omega-6 fatty acids in food by capillary electrophoresis.

PubMed

Soliman, Laiel C; Donkor, Kingsley K; Church, John S; Cinel, Bruno; Prema, Dipesh; Dugan, Michael E R

2013-10-01

A lower dietary omega-6/omega-3 (n-6/n-3) fatty acid ratio (<4) has been shown to be beneficial in preventing a number of chronic illnesses. Interest exists in developing more rapid and sensitive analytical methods for profiling fatty acid levels in foods. An aqueous CE method was developed for the simultaneous determination of 15 n-3 and n-6 relevant fatty acids. The effect of pH and concentration of buffer, type and concentration of organic modifier, and additive on the separation was investigated in order to determine the best conditions for the analysis. Baseline separations of the 15 fatty acids were achieved using 40 mM borate buffer at pH 9.50 containing 50 mM SDS, 10 mM β-cyclodextrin, and 10% acetonitrile. The developed CE method has LODs of <5 mg/L and good linearity (R(2) > 0.980) for all fatty acids studied. The proposed method was successfully applied to the determination of n-3 and n-6 fatty acids in flax seed, Udo® oils and a selection of grass-fed and grain-fed beef muscle samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Linking Microbial Community Structure and Function During the Acidified Anaerobic Digestion of Grass

PubMed Central

Joyce, Aoife; Ijaz, Umer Z.; Nzeteu, Corine; Vaughan, Aoife; Shirran, Sally L.; Botting, Catherine H.; Quince, Christopher; O’Flaherty, Vincent; Abram, Florence

2018-01-01

Harvesting valuable bioproducts from various renewable feedstocks is necessary for the critical development of a sustainable bioeconomy. Anaerobic digestion is a well-established technology for the conversion of wastewater and solid feedstocks to energy with the additional potential for production of process intermediates of high market values (e.g., carboxylates). In recent years, first-generation biofuels typically derived from food crops have been widely utilized as a renewable source of energy. The environmental and socioeconomic limitations of such strategy, however, have led to the development of second-generation biofuels utilizing, amongst other feedstocks, lignocellulosic biomass. In this context, the anaerobic digestion of perennial grass holds great promise for the conversion of sustainable renewable feedstock to energy and other process intermediates. The advancement of this technology however, and its implementation for industrial applications, relies on a greater understanding of the microbiome underpinning the process. To this end, microbial communities recovered from replicated anaerobic bioreactors digesting grass were analyzed. The bioreactors leachates were not buffered and acidic pH (between 5.5 and 6.3) prevailed at the time of sampling as a result of microbial activities. Community composition and transcriptionally active taxa were examined using 16S rRNA sequencing and microbial functions were investigated using metaproteomics. Bioreactor fraction, i.e., grass or leachate, was found to be the main discriminator of community analysis across the three molecular level of investigation (DNA, RNA, and proteins). Six taxa, namely Bacteroidia, Betaproteobacteria, Clostridia, Gammaproteobacteria, Methanomicrobia, and Negativicutes accounted for the large majority of the three datasets. The initial stages of grass hydrolysis were carried out by Bacteroidia, Gammaproteobacteria, and Negativicutes in the grass biofilms, in addition to Clostridia in the bioreactor leachates. Numerous glycolytic enzymes and carbohydrate transporters were detected throughout the bioreactors in addition to proteins involved in butanol and lactate production. Finally, evidence of the prevalence of stressful conditions within the bioreactors and particularly impacting Clostridia was observed in the metaproteomes. Taken together, this study highlights the functional importance of Clostridia during the anaerobic digestion of grass and thus research avenues allowing members of this taxon to thrive should be explored. PMID:29619022

Climate Change and Mountain Community Fire Management in the Cordillera Blanca, Peru

NASA Astrophysics Data System (ADS)

All, J.; Medler, M.; Cole, R. J.; Arques, S.; Schmitt, C. G.

2014-12-01

In the central Andes of Peru, climate change is altering fire risk through changes in local meteorology and fuel loading. Greater moisture and favorable growing conditions are increasing vegetative productivity, which in turn increases fuel loads. This process is accentuated during El Nino events and potentially results in increased fire occurrence and frequency during relatively dry La Nina events. Park officials are concerned about the ramification of the changes on local ecology and tourist use of the resources. However, using a time-series of two different products from the MODIS Terra and Aqua platforms (Active Fire and Burned Area), TRMM 3B43 precipitation data, and Multivariate ENSO Index data we document fire occurrence and extent from 2000 to 2010 and our analysis indicates that fires are burning exclusively during winter months when there are no natural ignition sources. Globally, fire is used in conjunction with grazing to improve the regeneration and yield of grasses. During our interviews, locals claimed to only set fires in the buffer zone outside of the park, but our analysis indicates that the buffer zone rarely burns and that most fires begin within the park and only occasionally move into the buffer zones. Additionally, we determined that although this is small-scale fire activity every year, overall fire is having a very minor effect on local systems. The park service must develop programs to work with local grazing stakeholders to better limit the impacts of fire, while also address the negative perceptions from tourists in the future. In this instance, fire perception and fire reality are not the same and the challenge for resource managers is how to reconcile these two factors in order to more effectively manage the parklands.

Facilitation or Competition? Tree Effects on Grass Biomass across a Precipitation Gradient

PubMed Central

Moustakas, Aristides; Kunin, William E.; Cameron, Tom C.; Sankaran, Mahesh

2013-01-01

Savanna ecosystems are dominated by two distinct plant life forms, grasses and trees, but the interactions between them are poorly understood. Here, we quantified the effects of isolated savanna trees on grass biomass as a function of distance from the base of the tree and tree height, across a precipitation gradient in the Kruger National Park, South Africa. Our results suggest that mean annual precipitation (MAP) mediates the nature of tree-grass interactions in these ecosystems, with the impact of trees on grass biomass shifting qualitatively between 550 and 737 mm MAP. Tree effects on grass biomass were facilitative in drier sites (MAP≤550 mm), with higher grass biomass observed beneath tree canopies than outside. In contrast, at the wettest site (MAP = 737 mm), grass biomass did not differ significantly beneath and outside tree canopies. Within this overall precipitation-driven pattern, tree height had positive effect on sub-canopy grass biomass at some sites, but these effects were weak and not consistent across the rainfall gradient. For a more synthetic understanding of tree-grass interactions in savannas, future studies should focus on isolating the different mechanisms by which trees influence grass biomass, both positively and negatively, and elucidate how their relative strengths change over broad environmental gradients. PMID:23451137

Local versus landscape-scale effects of savanna trees on grasses

USGS Publications Warehouse

Riginos, C.; Grace, J.B.; Augustine, D.J.; Young, T.P.

2009-01-01

1. Savanna ecosystems - defined by the coexistence of trees and grasses - cover more than one-fifth the world's land surface and harbour most of the world's rangelands, livestock and large mammal diversity. Savanna trees can have a variety of effects on grasses, with consequences for the wild and domestic herbivores that depend on them. 2.Studies of these effects have focused on two different spatial scales. At the scale of individual trees, many studies have shown net positive effects of trees on sub-canopy grass nutrient concentrations and biomass. At the landscape scale, other studies have shown negative effects of high tree densities on grass productivity. These disparate results have led to different conclusions about the effects of trees on forage quality and ungulate nutrition in savannas. 3.We integrate these approaches by examining the effects of trees on grasses at both spatial scales and across a range of landscape-scale tree densities. 4.We quantified grass biomass, species composition and nutrient concentrations in these different contexts in an Acacia drepanolobium savanna in Laikipia, Kenya. Individual trees had positive effects on grass biomass, most likely because trees enrich soil nitrogen. Grass leaf phosphorus in sub-canopy areas, however, was depressed. The effects of individual trees could explain the effects of increasing landscape-scale tree cover for the biomass of only two of the four dominant grass species. 5.The negative effects of trees on grass and soil phosphorus, combined with depressed grass productivity in areas of high tree cover, suggest that ungulate nutrition may be compromised in areas with many trees. 6.Synthesis. We conclude that few, isolated trees may have positive local effects on savanna grasses and forage, but in areas of high tree density the negative landscape-scale effects of trees are likely to outweigh these positive effects. In savannas and other patchy landscapes, attempts to predict the consequences of changes in patch abundances for ecosystem services (e.g. rangeland productivity and carbon sequestration) will depend on our understanding of the extent to which local, patch-scale dynamics do or do not predict landscape-scale dynamics. ?? 2009 British Ecological Society.

[Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].

PubMed

Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen

2013-01-01

By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0.925 Pa, respectively.

Methane Production of Different Forages in In vitro Ruminal Fermentation

PubMed Central

Meale, S. J.; Chaves, A. V.; Baah, J.; McAllister, T. A.

2012-01-01

An in vitro rumen batch culture study was completed to compare effects of common grasses, leguminous shrubs and non-leguminous shrubs used for livestock grazing in Australia and Ghana on CH4 production and fermentation characteristics. Grass species included Andropodon gayanus, Brachiaria ruziziensis and Pennisetum purpureum. Leguminous shrub species included Cajanus cajan, Cratylia argentea, Gliricidia sepium, Leucaena leucocephala and Stylosanthes guianensis and non-leguminous shrub species included Annona senegalensis, Moringa oleifera, Securinega virosa and Vitellaria paradoxa. Leaves were harvested, dried at 55°C and ground through a 1 mm screen. Serum bottles containing 500 mg of forage, modified McDougall’s buffer and rumen fluid were incubated under anaerobic conditions at 39°C for 24 h. Samples of each forage type were removed after 0, 2, 6, 12 and 24 h of incubation for determination of cumulative gas production. Methane production, ammonia concentration and proportions of VFA were measured at 24 h. Concentration of aNDF (g/kg DM) ranged from 671 to 713 (grasses), 377 to 590 (leguminous shrubs) and 288 to 517 (non-leguminous shrubs). After 24 h of in vitro incubation, cumulative gas, CH4 production, ammonia concentration, proportion of propionate in VFA and IVDMD differed (p<0.05) within each forage type. B. ruziziensis and G. sepium produced the highest cumulative gas, IVDMD, total VFA, proportion of propionate in VFA and the lowest A:P ratios within their forage types. Consequently, these two species produced moderate CH4 emissions without compromising digestion. Grazing of these two species may be a strategy to reduce CH4 emissions however further assessment in in vivo trials and at different stages of maturity is recommended. PMID:25049482

Spatial-Temporal Variations of Water Quality and Its Relationship to Land Use and Land Cover in Beijing, China

PubMed Central

Chen, Xiang; Zhou, Weiqi; Pickett, Steward T. A.; Li, Weifeng; Han, Lijian

2016-01-01

Rapid urbanization with intense land use and land cover (LULC) change and explosive population growth has a great impact on water quality. The relationship between LULC characteristics and water quality provides important information for non-point sources (NPS) pollution management. In this study, we first quantified the spatial-temporal patterns of five water quality variables in four watersheds with different levels of urbanization in Beijing, China. We then examined the effects of LULC on water quality across different scales, using Pearson correlation analysis, redundancy analysis, and multiple regressions. The results showed that water quality was improved over the sampled years but with no significant difference (p > 0.05). However, water quality was significantly different among nonurban and both exurban and urban sites (p < 0.05). Forest land was positively correlated with water quality and affected water quality significantly (p < 0.05) within a 200 m buffer zone. Impervious surfaces, water, and crop land were negatively correlated with water quality. Crop land and impervious surfaces, however, affected water quality significantly (p < 0.05) for buffer sizes greater than 800 m. Grass land had different effects on water quality with the scales. The results provide important insights into the relationship between LULC and water quality, and thus for controlling NPS pollution in urban areas. PMID:27128934

Nitrous oxide emission from cropland and adjacent riparian buffers in contrasting hydrogeomorphic settings.

PubMed

Fisher, K; Jacinthe, P A; Vidon, P; Liu, X; Baker, M E

2014-01-01

Riparian buffers are important nitrate (NO) sinks in agricultural watersheds, but limited information is available regarding the intensity and control of nitrous oxide (NO) emission from these buffers. This study monitored (December 2009-May 2011) NO fluxes at two agricultural riparian buffers in the White River watershed in Indiana to assess the impact of land use and hydrogeomorphologic (HGM) attributes on emission. The study sites included a riparian forest in a glacial outwash/alluvium setting (White River [WR]) and a grassed riparian buffer in tile-drained till plains (Leary Weber Ditch [LWD]). Adjacent corn ( L.) fields were monitored for land use assessment. Analysis of variance identified season, land use (riparian buffer vs. crop field), and site geomorphology as major drivers of NO fluxes. Strong relationships between N mineralization and NO fluxes were found at both sites, but relationships with other nutrient cycling indicators (C/N ratio, dissolved organic C, microbial biomass C) were detected only at LWD. Nitrous oxide emission showed strong seasonal variability; the largest NO peaks occurred in late spring/early summer as a result of flooding at the WR riparian buffer (up to 27.8 mg NO-N m d) and N fertilizer application to crop fields. Annual NO emission (kg NO-N ha) was higher in the crop fields (WR: 7.82; LWD: 6.37) than in the riparian areas. A significant difference ( < 0.02) in annual NO emission between the riparian buffers was detected (4.32 vs. 1.03 kg NO-N ha at WR and LWD, respectively), and this difference was attributed to site geomorphology and flooding (WR is flood prone; no flooding occurred at tile-drained LWD). The study results demonstrate the significance of landscape geomorphology and land-stream connection (i.e., flood potential) as drivers of NO emission in riparian buffers and therefore argue that an HGM-based approach should be especially suitable for determination of regional NO budget in riparian ecosystems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Reversing land degradation through grasses: a systematic meta-analysis in the Indian tropics

NASA Astrophysics Data System (ADS)

Mandal, Debashis; Srivastava, Pankaj; Giri, Nishita; Kaushal, Rajesh; Cerda, Artemi; Meherul Alam, Nurnabi

2017-02-01

Although intensive agriculture is necessary to sustain the world's growing population, accelerated soil erosion contributes to a decrease in the environmental health of ecosystems at local, regional and global scales. Reversing the process of land degradation using vegetative measures is of utmost importance in such ecosystems. The present study critically analyzes the effect of grasses in reversing the process of land degradation using a systematic review. The collected information was segregated under three different land use and land management situations. Meta-analysis was applied to test the hypothesis that the use of grasses reduces runoff and soil erosion. The effect of grasses was deduced for grass strip and in combination with physical structures. Similarly, the effects of grasses were analyzed in degraded pasture lands. The overall result of the meta-analysis showed that infiltration capacity increased approximately 2-fold after planting grasses across the slopes in agricultural fields. Grazing land management through a cut-and-carry system increased conservation efficiencies by 42 and 63 % with respect to reduction in runoff and erosion, respectively. Considering the comprehensive performance index (CPI), it has been observed that hybrid Napier (Pennisetum purpureum) and sambuta (Saccharum munja) grass seem to posses the most desirable attributes as an effective grass barrier for the western Himalayas and Eastern Ghats, while natural grass (Dichanthium annulatum) and broom grass (Thysanolaena maxima) are found to be most promising grass species for the Konkan region of the Western Ghats and the northeastern Himalayan region, respectively. In addition to these benefits, it was also observed that soil carbon loss can be reduced by 83 % with the use of grasses. Overall, efficacy for erosion control of various grasses was more than 60 %; hence, their selection should be based on the production potential of these grasses under given edaphic and agro-ecological conditions. The present analysis also indicated that grass must be used as a vegetative strip to maintain soil quality in sloppy arable areas (8.5 Mha) of Indian hilly regions. Similarly, due attention should be paid for establishing grasses in 3 Mha of degraded pasture lands and 3.5 Mha of shifting cultivation areas in India to reverse the land degradation.

Agricultural runoff pollution control by a grassed swales coupled with wetland detention ponds system: a case study in Taihu Basin, China.

PubMed

Zhao, Jinhui; Zhao, Yaqian; Zhao, Xiaoli; Jiang, Cheng

2016-05-01

The performance of a field grassed swales (GSs) coupled with wetland detention ponds (WDPs) system was monitored under four typical rainfall events to assess its effectiveness on agricultural runoff pollution control in Taihu Basin, China. The results indicated that suspended solids (SS) derived from the flush process has significant influence on pollution loads in agricultural runoff. Determination of first flush effect (FFE) indicated that total suspended solids (TSS) and total phosphorus (TP) exhibited moderate FFE, while chemical oxygen demand (COD) and total nitrogen (TN) showed weak FFE. Average removal efficiencies of 83.5 ± 4.5, 65.3 ± 6.8, 91.6 ± 3.8, and 81.3 ± 5.8 % for TSS, COD, TN, and TP were achieved, respectively. The GSs played an important role in removing TSS and TP and acted as a pre-treatment process to prevent clogging of the subsequent WDPs. Particle size distributions (PSDs) analysis indicated that coarse particles larger than 75 μm accounted for 80 % by weight of the total particles in the runoff. GSs can effectively reduce coarse particles (≥75 μm) in runoff, while its removal efficiency for fine particles (<75 μm) was low, even minus results being recorded, especially for particles smaller than 25 μm. The length of GSs is a key factor in its performance. The WDPs can remove particles of all sizes by sedimentation. In addition, WDPs can improve water quality due to their buffering and dilution capacity during rainfall as well as their water purification ability during dry periods. Overall, the ecological system of GSs coupled with WDPs is an effective system for agricultural runoff pollution control.

Magnitude of efficacy measurements in grass allergy immunotherapy trials is highly dependent on pollen exposure.

PubMed

Durham, S R; Nelson, H S; Nolte, H; Bernstein, D I; Creticos, P S; Li, Z; Andersen, J S

2014-05-01

The objective was to evaluate the association between grass pollen exposure, allergy symptoms and impact on measured treatment effect after grass sublingual immunotherapy (SLIT)-tablet treatment. The association between grass pollen counts and total combined rhinoconjunctivitis symptom and medication score (TCS) was based on a post hoc analysis of data collected over six trials and seven grass pollen seasons across North America and Europe, including 2363 subjects treated with grass SLIT-tablet or placebo. Daily pollen counts were obtained from centralized pollen databases. The effect of treatment on the relationship between the TCS and pollen counts was investigated, and the relative difference between grass SLIT-tablet and placebo as a function of average grass pollen counts was modelled by linear regression. The magnitude of treatment effect based on TCS was greater with higher pollen exposure (P < 0.001). The relative treatment effect in terms of TCS for each trial was correlated with the average grass pollen exposure during the first period of the season, with predicted reduction in TCS = 12% + 0.35% × pollen count (slope significantly different from 0, P = 0.003; R(2)  = 0.66). Corresponding correlations to the entire grass pollen season and to the peak season were equally good, whereas there was a poor correlation between difference in measured efficacy and pollen exposure during the last part of the season. In seasonal allergy trials with grass SLIT-tablet, the observed treatment effect is highly dependent on pollen exposure with the magnitude being greater with higher pollen exposure. This is an important relationship to consider when interpreting individual clinical trial results. © 2014 The Authors. Allergy Published by John Wiley & Sons Ltd.

Magnitude of efficacy measurements in grass allergy immunotherapy trials is highly dependent on pollen exposure

PubMed Central

Durham, S R; Nelson, H S; Nolte, H; Bernstein, D I; Creticos, P S; Li, Z; Andersen, J S

2014-01-01

Background The objective was to evaluate the association between grass pollen exposure, allergy symptoms and impact on measured treatment effect after grass sublingual immunotherapy (SLIT)-tablet treatment. Methods The association between grass pollen counts and total combined rhinoconjunctivitis symptom and medication score (TCS) was based on a post hoc analysis of data collected over six trials and seven grass pollen seasons across North America and Europe, including 2363 subjects treated with grass SLIT-tablet or placebo. Daily pollen counts were obtained from centralized pollen databases. The effect of treatment on the relationship between the TCS and pollen counts was investigated, and the relative difference between grass SLIT-tablet and placebo as a function of average grass pollen counts was modelled by linear regression. Results The magnitude of treatment effect based on TCS was greater with higher pollen exposure (P < 0.001). The relative treatment effect in terms of TCS for each trial was correlated with the average grass pollen exposure during the first period of the season, with predicted reduction in TCS = 12% + 0.35% × pollen count (slope significantly different from 0, P = 0.003; R2 = 0.66). Corresponding correlations to the entire grass pollen season and to the peak season were equally good, whereas there was a poor correlation between difference in measured efficacy and pollen exposure during the last part of the season. Conclusions In seasonal allergy trials with grass SLIT-tablet, the observed treatment effect is highly dependent on pollen exposure with the magnitude being greater with higher pollen exposure. This is an important relationship to consider when interpreting individual clinical trial results. PMID:24605984

Impacts of hydraulic redistribution on overstory-understory interactions in a semiarid savanna

NASA Astrophysics Data System (ADS)

Barron-Gafford, G.; Minor, R. L.; Hendryx, S.; Lee, E.; Sutter, L., Jr.; Colella, A.; Murphy, P.; Sanchez-Canete, E. P.; Hamerlynck, E. P.; Kumar, P.; Scott, R. L.

2016-12-01

Hydraulic redistribution (HR) is an important ecohydrological process in dryland environments by which plants preferentially move water from wet to dry soil layers. How does this water movement by the overstory influence physiological activity in the understory? Are there periods of facilitation when the tree is lifting water and periods of competition when the water is being moved deeper in the profile? We combined trunk, lateral root, and taproot sap flow data, and linked these measures with shallow and deep soil moisture data to show that soil moisture gradients control hydraulic redistribution in overstory mesquite trees. During prolonged inter-rain periods of drought and in response to periods of high vapor pressure deficits, mesquites drew upon this deeper, stored water to meet biological demands. We created plots under mesquite that experienced HR and plots where HR was physically prohibited to quantify the impacts of HR on understory performance. We measured carbon and water exchange at the leaf-level on mesquite and understory grass and for entire understory ecosystem using a large, portable chamber. We found that HR provided a drought-buffering capacity for the overstory mesquite and a significant decrease in mesquite photosynthesis in trees where the capacity for HR was reduced. While we had hypothesized that water lifted by the mesquite in periods of drought would facilitate understory grass function, we found no evidence for this. In fact, we found that grasses actually conducted higher rates of photosynthesis in plots where HR was eliminated. Ultimately, we found that HR in upland savannas, where there is little to no access to deep water, yields a competitive interaction between overstory mesquites and understory grasses at the scale of individual precipitation pulse events and across entire growing seasons.

Positive and negative effects of grass, cattle, and wild herbivores on Acacia saplings in an East African savanna.

PubMed

Riginos, Corinna; Young, Truman P

2007-10-01

Plant-plant interactions can be a complex mixture of positive and negative interactions, with the net outcome depending on abiotic and community contexts. In savanna systems, the effects of large herbivores on tree-grass interactions have rarely been studied experimentally, though these herbivores are major players in these systems. In African savannas, trees often become more abundant under heavy cattle grazing but less abundant in wildlife preserves. Woody encroachment where cattle have replaced wild herbivores may be caused by a shift in the competitive balance between trees and grasses. Here we report the results of an experiment designed to quantify the positive, negative, and net effects of grasses, wild herbivores, and cattle on Acacia saplings in a Kenyan savanna. Acacia drepanolobium saplings under four long-term herbivore regimes (wild herbivores, cattle, cattle + wild herbivores, and no large herbivores) were cleared of surrounding grass or left with the surrounding grass intact. After two years, grass-removal saplings exhibited 86% more browse damage than control saplings, suggesting that grass benefited saplings by protecting them from herbivory. However, the negative effect of grass on saplings was far greater; grass-removal trees accrued more than twice the total stem length of control trees. Where wild herbivores were present, saplings were browsed more and produced more new stem growth. Thus, the net effect of wild herbivores was positive, possibly due to the indirect effects of lower competitor tree density in areas accessible to elephants. Additionally, colonization of saplings by symbiotic ants tracked growth patterns, and colonized saplings experienced lower rates of browse damage. These results suggest that savanna tree growth and woody encroachment cannot be predicted by grass cover or herbivore type alone. Rather, tree growth appears to depend on a variety of factors that may be acting together or antagonistically at different stages of the tree's life cycle.

Research on screening of suitable forage grasses in coastal saline - alkaline soil

NASA Astrophysics Data System (ADS)

Yue, Xiaoyu; Han, Xin; Song, Qianhong; Yang, Xu; Zhou, Qingyun

2017-11-01

The screening of salt-tolerant plants can provide suitable tree species for the afforestation of coastal salinity and maintain biodiversity and ecological stability. The research was based on the study of seven grasses, such as high fescue, the bermuda grass, the thyme, the rye grass, the precocious grass, the third leaf, and the red three leaves. Each pasture was planted in three different kinds of soil, such as salt alkali soil, salt alkali soil + ecological bag and non-saline alkali soil. The effect of salt alkali soil on germinating time, germination rate and grass growth was analyzed. The effects of ecological bag on soil salt and the growth and germination of grass was also analyzed in order to provide the reference basis for the widespread and systematic selection of salt-tolerant plants, with the grass being selected for the suitable ecological bag.

Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

NASA Astrophysics Data System (ADS)

Sharma, Disha; Kulshrestha, Umesh

Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

Soil conservation through sediment trapping: A review

NASA Astrophysics Data System (ADS)

Mekonnen, Mulatie; Keesstra, Saskia; Baartman, Jantiene; Maroulis, Jerry; Stroosnijder, Leo

2014-05-01

Preventing the off-site effects of soil erosion is an essential part of good catchment management. Most efforts are in the form of on-site soil and water conservation measures. However, sediment trapping (ST) can be an alternative (or additional) measure to prevent the negative off-site effects of soil erosion. Therefore, not all efforts should focus solely on on-site soil conservation, but also on the safe routing of sediment-laden flows and on creating sites and conditions where sediment can be trapped, preferably in a cost effective or even profitable way. ST can be applied on-site (in-field) and off-site and involves both vegetative and structural measures. The main vegetative measures include grass strips, tree or bush buffers, grassed waterways and restoration of the waterways and their riparian zone; while structural measures include terraces, ponds and check dams. This paper provides a review of studies that have assessed the sediment trapping efficacy (STE) of such vegetative and structural measures. Vegetation type and integration of two or more measures (vegetative as well as structural) are important factors influencing STE. In this review, the STE of most measures was evaluated either individually or in such combinations. In real landscape situations, it is not only important to select the most efficient erosion control measures, but also to determine their optimum location in the catchment. Hence, there is a need for research that shows a more integrated determination of STE at the catchment scale. If integrated measures are implemented at the most appropriate spatial locations within a catchment where they can disconnect landscape units from each other, they will decrease runoff velocity and sediment transport and, subsequently, reduce downstream flooding and sedimentation problems. KEY WORDS: Integrated sediment trapping, sediment trapping efficacy, vegetative, structural, on-site and off-site measures.

The buffering capacity of stems: genetic architecture of nonstructural carbohydrates in cultivated Asian rice, Oryza sativa.

PubMed

Wang, Diane R; Han, Rongkui; Wolfrum, Edward J; McCouch, Susan R

2017-07-01

Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant-based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves. We map out a blueprint of the genetic architecture of rice (Oryza sativa) stem nonstructural carbohydrates (NSC) at two critical developmental time-points using a subpopulation-specific genome-wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population. Overall, 26 QTL are identified; three are detected in multiple panels and are associated with starch-at-maturity, sucrose-at-maturity and NSC-at-heading. They tag OsHXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters. This study provides the foundation for more in-depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The buffering capacity of stems: genetic architecture of nonstructural carbohydrates in cultivated Asian rice, Oryza sativa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Diane R.; Han, Rongkui; Wolfrum, Edward J.

Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant-based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves. We map out a blueprint of the genetic architecture of rice ( Oryza sativa) stem nonstructural carbohydrates (NSC) at two critical developmental time-points using a subpopulation-specific genome-wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population. Overall, 26 QTL are identified; three are detected in multiple panels and are associatedmore » with starch-at-maturity, sucrose-at-maturity and NSC-at-heading. They tag OsHXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters. Furthermore, this study provides the foundation for more in-depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species.« less

The buffering capacity of stems: genetic architecture of nonstructural carbohydrates in cultivated Asian rice, Oryza sativa

DOE PAGES

Wang, Diane R.; Han, Rongkui; Wolfrum, Edward J.; ...

2017-05-30

Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant-based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves. We map out a blueprint of the genetic architecture of rice ( Oryza sativa) stem nonstructural carbohydrates (NSC) at two critical developmental time-points using a subpopulation-specific genome-wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population. Overall, 26 QTL are identified; three are detected in multiple panels and are associatedmore » with starch-at-maturity, sucrose-at-maturity and NSC-at-heading. They tag OsHXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters. Furthermore, this study provides the foundation for more in-depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species.« less

Changes of the Shrub/Grass balance under Climate Change: Mechanisms and Consequences

NASA Astrophysics Data System (ADS)

Sala, O.; Gherardi, L.; Anadon, J.

2016-12-01

Most arid and semiarid ecosystems are made up of grasses and shrubs; and their balance could be altered by changes in climate, fire and grazing among others. Here, we focus on the effects of climate change on the shrub/grass balance and the mechanisms mediating alterations of the balance. We assess hypotheses that state that climate change affects shrub/grass balance by affecting the distribution of soil water in the profile. We report on studies that range from the plot to the sub-continental scale using manipulative experiments, simulation modelling and remote sensing tools. Specifically, we evaluate the effect of amount of precipitation on the shrub/grass balance. In Chihuahuan desert ecosystems, prolonged drought drove shrub encroachment as a result of a-symmetric competition between shrubs and grasses. Demise of shallow-rooted grasses after prolonged drought resulted in an increase in soil-water resources for deep-rooted shrubs. We also quantitatively assessed the effect of changes in shrub/grass balance on the provisioning of ecosystem services in North and South America. In both regions, woody-plant encroachment reduced livestock production, which is the main ecosystem service provided by drylands. However, the effect of woody-plant encroachment had a larger impact in South than North America. The differential effect of changes in the shrub/balance was mediated by differences in the demand of ecosystem services.

Cost-effectiveness of grass allergen tablet (GRAZAX) for the prevention of seasonal grass pollen induced rhinoconjunctivitis - a Northern European perspective.

PubMed

Bachert, C; Vestenbaek, U; Christensen, J; Griffiths, U K; Poulsen, P B

2007-05-01

The prevalence of allergic rhinoconjunctivitis has increased dramatically. Seventeen million people in the United Kingdom, Germany, the Netherlands, Sweden, Denmark, Norway and Finland suffer from grass pollen induced allergic rhinitis. Symptomatic therapy with antihistamines and topical steroids is partially effective but allergen-specific immunotherapy by injection or sublingual routes is superior. The grass allergen tablet (GRAZAX) is a new allergen-specific immunotherapy for home administration. To assess the cost-effectiveness of the grass allergen tablet compared with symptomatic medication in seven Northern European countries. A prospective pharmacoeconomic analysis was carried out alongside a multinational clinical trial. Pooled data on resource use and health outcomes were collected. A societal perspective was adopted, and the analysis had a 9-year time horizon. The outcome measure was Quality Adjusted Life Years (QALYs). The grass allergen tablet was clinically superior to symptomatic treatment, producing statistically significant differences for all efficacy end-points, including the number of QALYs gained - 0.976 vs. 0.947 QALYs gained. There was a significantly higher usage of the rescue medications loratadine and budesonide, and more hours missed from work (production loss), in the symptomatic treatment group. The cost per QALY gained in the grass allergen tablet group was similar in the seven countries (euro 12,930 to euro 18,263 for an annual cost of the grass allergen tablet of euro 1500). The analysis showed that the grass allergen tablet was cost-effective for all countries for an annual treatment cost below euro 2200. The pharmacoeconomic analysis illustrated that allergen-specific immunotherapy with the grass allergen tablet is a cost-effective intervention for the prevention of grass pollen induced rhinoconjunctivitis in Northern European countries, for a tablet price below euro 6. In Germany for example the price of the tablet is euro 2.95 corresponding to a yearly treatment cost of euro 358 - based on a 9-year time horizon.

Guidelines for prescribed burning sagebrush-grass rangelands in the northern Great Basin

Treesearch

Stephen C. Bunting; Bruce M. Kilgore; Charles L. Bushey

1987-01-01

Summarizes recent literature on the effects of fire on sagebrush-grass vegetation. Also outlines procedures and considerations for planning and conducting prescribed fires and monitoring effects. Includes a comprehensive annotated bibliography of the fire-sagebrush-grass literature published since 1980.

Phosphorus load to surface water from bank erosion in a Danish lowland river basin.

PubMed

Kronvang, Brian; Audet, Joachim; Baattrup-Pedersen, Annette; Jensen, Henning S; Larsen, Søren E

2012-01-01

Phosphorus loss from bank erosion was studied in the catchment of River Odense, a lowland Danish river basin, with the aim of testing the hypothesis of whether stream banks act as major diffuse phosphorus (P) sources at catchment scale. Furthermore, the study aimed at analyzing the impact of different factors influencing bank erosion and P loss such as stream order, anthropogenic disturbances, width of uncultivated buffer strips, and the vegetation of buffer strips. A random stratified procedure in geographical information system (GIS) was used to select two replicate stream reaches covering different stream orders, channelized vs. naturally meandering channels, width of uncultivated buffer strips (≤ 2 m and ≥ 10 m), and buffer strips with different vegetation types. Thirty-six 100-m stream reaches with 180 bank plots and a total of 3000 erosion pins were established in autumn 2006, and readings were conducted during a 3-yr period (2006-2009). The results show that neither stream size nor stream disturbance measured as channelization of channel or the width of uncultivated buffer strip had any significant ( < 0.05) influence on bank erosion and P losses during each of the 3 yr studied. In buffer strips with natural trees bank erosion was significantly ( < 0.05) lower than in buffer strips dominated by grass and herbs. Gross and net P input from bank erosion amounted to 13.8 to 16.5 and 2.4 to 6.3 t P, respectively, in the River Odense catchment during the three study years. The net P input from bank erosion equaled 17 to 29% of the annual total P export and 21 to 62% of the annual export of P from diffuse sources from the River Odense catchment. Most of the exported total P was found to be bioavailable (71.7%) based on a P speciation of monthly suspended sediment samples collected at the outlet of the river basin. The results found in this study have a great importance for managers working with P mitigation and modeling at catchment scale. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Beneficial effects of neotyphodium tembladerae and neotyphodium pampeanum on a wild forage grass

USDA-ARS?s Scientific Manuscript database

Asexual, vertically transmitted fungal endophytes of the genus Neotyphodium are considered to enhance growth, stress resistance and competitiveness of agronomic grasses, but have been suggested to have neutral or deleterious effects on wild grasses. We studied whether the associations between Bromus...

Beneficial effects of Neotyphodium tembladerae and Neotyphodium pampeanum on a wild forage grass

USDA-ARS?s Scientific Manuscript database

Asexual, vertically transmitted fungal endophytes of the genus Neotyphodium are considered to enhance growth, stress resistance and competitiveness of agronomic grasses, but have been suggested to have neutral or deleterious effects on wild grasses. We studied whether the associations between Bromus...

Effects of triploid grass carp on aquatic plants, water quality, and public satisfaction in Washington State

USGS Publications Warehouse

Bonar, Scott A.; Bolding, B.; Divens, M.

2002-01-01

We investigated effects of triploid grass carp Ctenopharyngodon idella on aquatic macrophyte communities, water quality, and public satisfaction for 98 lakes and ponds in Washington State stocked with grass carp between 1990 and 1995. Grass carp had few noticeable effects on macrophyte communities until 19 months following stocking. After 19 months, submersed macrophytes were either completely eradicated (39% of the lakes) or not controlled (42% of the lakes) in most lakes. Intermediate control of submersed macrophytes occurred in 18% of lakes at a median stocking rate of 24 fish per vegetated surface acre. Most of the landowners interviewed (83%) were satisfied with the results of introducing grass carp. For sites where all submersed macrophytes were eradicated, average turbidity was higher (11 nephelometric turbidity units, NTU) than at sites where macrophytes were controlled to intermediate levels (4 NTU) or unaffected by grass carp grazing (5 NTU). Chlorophyll a was not significantly different between levels of macrophyte control; therefore, we concluded that most of this turbidity was abiotic and not algal. Triploid grass carp were a popular control option and effectively grazed most submersed macrophytes in Washington State. However, calculating stocking rates based on landowner estimates of aquatic plant coverage rarely resulted in intermediate levels of aquatic plant control. Additionally, the effects of particular stocking rates varied considerably. We recommend against using grass carp in Washington lakes where eradication of submersed vegetation cannot be tolerated.

A decade of evaluating the ecological effects of grass filter strips on channelized agricultural headwater streams

USDA-ARS?s Scientific Manuscript database

Grass filter strips are a widely used conservation practice in the Midwestern United States for reducing nutrient, pesticide, and sediment inputs into agricultural streams. Previous studies have documented the effectiveness of grass filter strips in reducing the input of agricultural pollutants, bu...

Effects of grass competition on bitterbrush: second-year report

Treesearch

H. Reed Sanderson; Richard L. Hubbard; Donald W. Seegrist

1963-01-01

The second year's data of a study designed to test the effects of perennial grass competition on the vigor of bitterbrush (Purshia tridentata) in an area of heavy bitterbrush mortality are reported. The data demonstrated that competition from other plants, mainly perennial grass, significantly reduced bitterbrush growth.

Detrimental and neutral effects of a wild grass-fungal endophyte symbiotum on insect preference and performance.

PubMed

Clement, Stephen L; Hu, Jinguo; Stewart, Alan V; Wang, Bingrui; Elberson, Leslie R

2011-01-01

Seed-borne Epichloë/Neotyphodium Glenn, Bacon, Hanlin (Ascomycota: Hypocreales: Clavicipitaceae) fungal endophytes in temperate grasses can provide protection against insect attack with the degree of host resistance related to the grass-endophyte symbiotum and the insect species involved in an interaction. Few experimental studies with wild grass-endophyte symbiota, compared to endophyte-infected agricultural grasses, have tested for anti-insect benefits, let alone for resistance against more than one insect species. This study quantified the preference and performance of the bird cherry oat-aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) and the cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae), two important pests of forage and cereal grasses, on Neotyphodium-infected (E+) and uninfected (E-) plants of the wild grass Alpine timothy, Phleum alpinum L. (Poales: Poaceae). The experiments tested for both constitutive and wound-induced resistance in E+ plants to characterize possible plasticity of defense responses by a wild E+ grass. The aphid, R. padi preferred E- over E+ test plants in choice experiments and E+ undamaged test plants constitutively expressed antibiosis resistance to this aphid by suppressing population growth. Prior damage of E+ test plants did not induce higher levels of resistance to R. padi. By contrast, the beetle, O. melanopus showed no preference for E+ or E- test plants and endophyte infection did not adversely affect the survival and development of larvae. These results extend the phenomenon of variable effects of E+ wild grasses on the preference and performance of phytophagous insects. The wild grass- Neotyphodium symbiotum in this study broadens the number of wild E+ grasses available for expanded explorations into the effects of endophyte metabolites on insect herbivory.

Indirect effects of an invasive annual grass on seed fates of two native perennial grass species

Treesearch

Susan E. Meyer; Katherine T. Merrill; Phil S. Allen; Julie Beckstead; Anna S. Norte

2014-01-01

Invasive plants exhibit both direct and indirect negative effects on recruitment of natives following invasion. We examined indirect effects of the invader Bromus tectorum (cheatgrass) on seed fates of two native grass species, Elymus elymoides and Pseudoroegneria spicata, by removing B. tectorum and by adding inoculum of the shared seed pathogen Pyrenophora...

Inter-annual Variability of Evapotranspiration in a Semi-arid Oak-savanna Ecosystem: Measured and Modeled Buffering to Precipitation Changes

NASA Astrophysics Data System (ADS)

Raz-Yaseef, N.; Sonnentag, O.; Kobayashi, H.; Baldocchi, D. D.

2010-12-01

Precipitation (P) is the primary control on vegetation dynamics and productivity, implying that climate induced disturbances in frequency and timing of P are intimately coupled with fluxes of carbon, water and energy. Future climate change is expected to increase extreme rainfall events as well as droughts, suggesting linked vegetation changes to an unknown extent. Semi-arid climates experience large inter-annual variability (IAV) in P, creating natural conditions adequate to study how year-to-year changes in P affect atmosphere-biosphere fluxes. We used a 10-year flux database collected at a semi-arid savanna site in order to: (1) define IAV in P by means of frequency and timing; (2) investigate how changes in P affect the ecohydrology of the forest and its partitioning into the main vapor fluxes, and (3) evaluate model capability to predict IAV of carbon and water fluxes above and below the canopy. This is based on the perception that the capability of process-oriented models to construct the deviation, and not the average, is important in order to correctly predict ecosystem sensitivity to climate change. Our research site was a low density and low LAI (0.8) semi-arid (P=523±180 mm yr-1) savanna site, combined of oaks and grass, and located at Tonzi ranch, California. Measurements of carbon and water fluxes above and below the tree canopy using eddy covariance and supplementary measurements have been made since 2001. Measured fluxes were compared to modeled based on two bio-meteorological process-oriented ecosystem models: BEPS and 3D-CAONAK. Our results show that IAV in P was large, and standard deviation (STD) was 38% of the average. Accordingly, the wet soil period (measured volumetric water content > 8%) varied between 156 days in dry years to 301 days in wet years. IAV of the vapor fluxes were lower than that of P (STD was 17% for the trees and 23% for the floor components), suggesting on ecosystem buffering to changes in P. The timing of grass green up was correlated with the timing of first rains, emphasizing the higher dependence of the floor component on P, as reflected in higher IAV of the grasses compared to the trees. On average, models simulated annual fluxes well (R2>0.93), but IAV of the trees was higher than measured (24%), mostly due to model underestimation during dry years. A threshold at P~500 mm yr-1 was observed (both in measurements and modeled results), above which tree transpiration barely increased. The high IAV of the floor component was not replicated in the models (SDV=5%), although this flux accounted for 55% of total ET. Based on our study we conclude that trees in this semi-arid ecosystem have developed adaptive mechanisms that buffer themselves from the year-to-year variations in precipitation.

Effects of dormant- vs. growing-season fire in shortgrass steppe: Biological soil crust and perennial grass responses

Treesearch

P. L. (Paulette) Ford; G. V. Johnson

2006-01-01

This research experimentally examined seasonal effects of fire on biological soil crusts and perennial grasses in shortgrass steppe. We predicted dormant-season fire would have greater negative effects on biological soil crusts than fire during the growing season, but less of an impact on perennial grasses than fire during the growing season. Treatments were dormant-...

Pesticide-contaminated feeds in integrated grass carp aquaculture: toxicology and bioaccumulation.

PubMed

Pucher, J; Gut, T; Mayrhofer, R; El-Matbouli, M; Viet, P H; Ngoc, N T; Lamers, M; Streck, T; Focken, U

2014-02-19

Effects of dissolved pesticides on fish are widely described, but little is known about effects of pesticide-contaminated feeds taken up orally by fish. In integrated farms, pesticides used on crops may affect grass carp that feed on plants from these fields. In northern Vietnam, grass carp suffer seasonal mass mortalities which may be caused by pesticide-contaminated plants. To test effects of pesticide-contaminated feeds on health and bioaccumulation in grass carp, a net-cage trial was conducted with 5 differently contaminated grasses. Grass was spiked with 2 levels of trichlorfon/fenitrothion and fenobucarb. Unspiked grass was used as a control. Fish were fed at a daily rate of 20% of body mass for 10 d. The concentrations of fenitrothion and fenobucarb in pond water increased over time. Effects on fish mortality were not found. Fenobucarb in feed showed the strongest effects on fish by lowering feed uptake, deforming the liver, increasing blood glucose and reducing cholinesterase activity in blood serum, depending on feed uptake. Fenobucarb showed increased levels in flesh in all treatments, suggesting bio-concentration. Trichlorfon and fenitrothion did not significantly affect feed uptake but showed concentration-dependent reduction of cholinesterase activity and liver changes. Fenitrothion showed bioaccumulation in flesh which was dependant on feed uptake, whereas trichlorfon was only detected in very low concentrations in all treatments. Pesticide levels were all detected below the maximum residue levels in food. The pesticide-contaminated feeds tested did not cause mortality in grass carp but were associated with negative physiological responses and may increase susceptibility to diseases.

Distribution, densities, and ecology of Siberian cranes in the Khroma River region of northern Yakutia in northeastern Russia

USGS Publications Warehouse

Bysykatova, Inga P.; Krapu, Gary L.; Germogenov, Nicolai I.; Buhl, Deborah A.; Aborn, David

2014-01-01

The Siberian crane (Grus leucogeranus) is the third rarest crane species in the world with a breeding range now centered on 3 core areas and a buffer zone in the arctic of northern Yakutia in northeastern Russia. During 16 July-2 August 2009, we undertook ground surveys within the Khroma River core breeding area, surrounding buffer zone, and lands lying to the west of the known rbeeding range to estimate densities and determine habitat use and social status of Siberian cranes. A total of 142 Siberian cranes were sighted (including 55 pairs) at 54 locations with 32 cranes (including 13 pairs) sighted outside the currently known breeding range in the lower drainages of the Syalakh and Syuryuktyakh Rivers. After adjusting for a probability of detection of 0.484 (95% CI = 0.281-0.833), Siberian crane densities in the Khroma core area and the buffer zone averaged 0.0921 cranes/km2 and 0.0363 cranes/km2, respectively. A majority of cranes (n = 93 [65%]) occurred in complexes of large basin wetlands, with use centered in those having extensive beds of pendant grass (Arctophila fulva). Of the 142 cranes seen, 110 (77%) were paired, 21 (15%) were singles, and 11 (8%) were in groups of 3-5. The Khroma core supports 1 of 2 large concentrations of breeding Siberian cranes remaining in the wild; therefore, we recommend that consideration be given to designating a nature reserve that would encompass the Khroma core, adjacent buffer zone, and lands to the west (including coastal tundra areas along the lower drainages of the Syalah and Syuryuktyah Rivers). Further research is needed to gain additional insight into Siberian crane distribution and numbers on lands beyond the currently delineated western boundary of the Siberian crane breeding range in the Ust-Yana District of northern Yakutia. Important gaps remain in information needed to effectively guide conservation efforts for the Eastern Population, and recent advances in remote tracking technology offer potential opportunities to help address several key information needs.

Anaerobic digestion of grass: the effect of temperature applied during the storage of substrate on the methane production.

PubMed

Míchal, Pavel; Švehla, Pavel; Plachý, Vladimír; Tlustoš, Pavel

2017-07-01

Within this research, biogas production, representation of methane in biogas and volatile solids (VSs) removal efficiency were compared using batch tests performed with the samples of intensively and extensively planted grasses originating from public areas. Before the batch tests, the samples were stored at different temperatures achievable on biogas plants applying trigeneration strategy (-18°C, +3°C, +18°C and +35°C). Specific methane production from intensively planted grasses was relatively high (0.33-0.41 m 3 /kg VS) compared to extensively planted grasses (0.20-0.33 m 3 /kg VS). VSs removal efficiency reached 59.8-68.8% for intensively planted grasses and 34.6-56.5% for extensively planted grasses. Freezing the intensively planted grasses at -18°C proved to be an effective thermal pretreatment leading to high biogas production (0.61 m 3 /kg total solid (TS)), high representation of methane (64.0%) in biogas and good VSs removal efficiency (68.8%). The results of this research suggest that public areas or sport parks seem to be available, cheap and at the same time very effective feedstock for biogas production.

Preliminary studies on allelopatic effect of some woody plants on seed germination of rye-grass and tall fescue.

PubMed

Arouiee, H; Nazdar, T; Mousavi, A

2010-11-01

In order to investigation of allelopathic effects of some ornamental trees on seed germination of rye-grass (Lolium prenne) and tall fescue (Festuca arundinaceae), this experiment was conducted in a randomized complete block design with 3 replicates at the laboratory of Horticultural Sciences Department of Ferdowsi University of Mashhad, during 2008. In this research, we studied the effect of aqueous and hydro-alcoholic extracts of Afghanistan pine (Pinus eldarica), arizona cypress (Cupressus arizonica), black locust (Robinia psedue acacia) and box elder (Acer negundo) leaves that prepared in 1:5 ratio on seed germination percent and rate for two grasses. The results showed that all extracts decreased statistically seed germination in compared to control treatment. The highest germination percentage and germination rate of tested grass detected in control treatment. Hydro-alcoholic extracts of all woody plants (15, 30%) were completely inhibited seed germination of rye-grass and tall fescue. Also aqueous extract of arizona cypress was completely inhibited seed germination of tall fescue and had more inhibitory activity than other aqueous extracts on rye-grass. Between aqueous extracts, the highest and lowest seed germination of rye-grass was found in Afghanistan pine and arizona cypress, respectively.

The Effects of Seed Ingestion by Livestock, Dung Fertilization, Trampling, Grass Competition and Fire on Seedling Establishment of Two Woody Plant Species

PubMed Central

Tjelele, Julius; Ward, David; Dziba, Luthando

2015-01-01

The increasing rate of woody plant encroachment in grasslands or savannas remains a challenge to livestock farmers. The causes and control measures of woody plant encroachment are of common interest, especially where it negatively affects the objectives of an agricultural enterprise. The objectives of this study were to determine the effects of gut passage (goats, cattle), dung (nutrients), fire, grass competition and trampling on establishment of A. nilotica and D. cinerea seedlings. Germination trials were subjected to the following treatments: 1) seed passage through the gut of cattle and goats and unpassed/ untreated seeds (i.e. not ingested), 2) dung and control (no dung), 3) grass and control (mowed grass), 4) fire and control (no fire), 5) trampling and control (no trampling). The interaction of animal species, grass and fire had an effect on seedling recruitment (P < 0.0052). Seeds retrieved from goats and planted with no grass and with fire (6.81% ± 0.33) had a significant effect on seedling recruitment than seeds retrieved from goats and planted with grass and no fire (2.98% ± 0.33). Significantly more D. cinerea and A. nilotica seeds germinated following seed ingestion by goats (3.59% ± 0.16) than cattle (1.93% ± 0.09) and control or untreated seeds (1.69% ± 0.11). Less dense grass cover, which resulted in reduced grass competition with tree seedlings for light, space and water, and improved seed scarification due to gut passage were vital for emergence and recruitment of Acacia seedlings. These results will contribute considerably to the understanding of the recruitment phase of woody plant encroachment. PMID:25695765

Development of new techniques of using irradiation in the genetic improvement of warm season grasses and an assessment of the genetic and cytogenetic effects. Progress report, November 1, 1977--October 31, 1978. [Pearl millet, Bermuda-grass, and coastcross

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanna, W.W.; Burton, G.W.

1978-05-01

Progress is reported on plant breeding programs for the genetic improvement of warm season grasses using irradiation as a tool. Data are included from studies on alteration of the protein quantity and quality in pearl millet grain by irradiation and mutation breeding; the effects of nitrogen and genotype on pearl millet grain; the effects of seed size on quality in pearl millet; irradiation breeding of sterile triploid turf Bermuda grasses; irradiation breeding of sterile coastcross-1, a forage grass, to increase winter hardiness; use of irradiation to induce resistance to rust disease; and an economic assessment of irradiation-induced mutants for plantmore » breeding programs.« less

Silicon, endophytes and secondary metabolites as grass defenses against mammalian herbivores

PubMed Central

Huitu, Otso; Forbes, Kristian M.; Helander, Marjo; Julkunen-Tiitto, Riitta; Lambin, Xavier; Saikkonen, Kari; Stuart, Peter; Sulkama, Sini; Hartley, Sue

2014-01-01

Grasses have been considered to primarily employ tolerance in lieu of defense in mitigating damage caused by herbivory. Yet a number of mechanisms have been identified in grasses, which may deter feeding by grazers. These include enhanced silicon uptake, hosting of toxin-producing endophytic fungi and induction of secondary metabolites. While these mechanisms have been individually studied, their synergistic responses to grazing, as well as their effects on grazers, are poorly known. A field experiment was carried out in 5 × 5 m outdoor enclosures to quantify phytochemical changes of either endophyte-infected (E+) or endophyte-free (E-) meadow fescue (Schedonorus pratensis) in response to medium intensity (corresponding with densities of ca. 1200 voles/ha for 5 weeks during 3 months) or heavy intensity (ca. 1200 voles/ha for 8 weeks during 3 months) grazing by a mammalian herbivore, the field vole (Microtus agrestis). A laboratory experiment was then conducted to evaluate the effects of endophyte infection status and grazing history of the grass diet on vole performance. As predicted, grazing increased foliar silicon content, by up to 13%. Grazing also increased foliar levels of phosphorous and several phenolic compounds, most notably those of the flavonols isorhamnetin-diglycoside and rhamnetin derivative. Silicon concentrations were consistently circa 16% higher in E+ grasses than in E-grasses, at all levels of grazing. Similarly, concentrations of chlorogenic acid derivative were found to be consistently higher in E+ than in E- grasses. Female voles maintained on heavily grazed grasses suffered higher mortality rates in the laboratory than female voles fed ungrazed grass, regardless of endophyte infection status. Our results conclusively demonstrate that, in addition to tolerance, grasses employ multi-tiered, effective defenses against mammalian grazers. PMID:25278951

The effect of trace element addition to mono-digestion of grass silage at high organic loading rates.

PubMed

Wall, David M; Allen, Eoin; Straccialini, Barbara; O'Kiely, Padraig; Murphy, Jerry D

2014-11-01

This study investigated the effect of trace element addition to mono-digestion of grass silage at high organic loading rates. Two continuous reactors were compared. The first mono-digested grass silage whilst the second operated in co-digestion, 80% grass silage with 20% dairy slurry (VS basis). The reactors were run for 65weeks with a further 5weeks taken for trace element supplementation for the mono-digestion of grass silage. The co-digestion reactor reported a higher biomethane efficiency (1.01) than mono-digestion (0.90) at an OLR of 4.0kgVSm(-3)d(-1) prior to addition of trace elements. Addition of cobalt, iron and nickel, led to an increase in the SMY in mono-digestion of grass silage by 12% to 404LCH4kg(-1)VS and attained a biomethane efficiency of 1.01. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blue wild-rye grass competition increases the effect of ozone on ponderosa pine seedlings.

PubMed

Andersen, C P; Hogsett, W E; Plocher, M; Rodecap, K; Lee, E H

2001-03-01

Individual ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings were grown in mesocosms with three densities of blue wild-rye grass (Elymus glaucus Buckl.) (equivalent to 0, 32 or 88 plants m-2) to determine if the presence of a natural competitor alters the response of ponderosa pine seedlings to ozone. After 3 years of ozone exposure, grass presence reduced total ponderosa pine dry mass by nearly 50%, whereas ozone alone had no significant effect on ponderosa pine growth. The combination of ozone and grass further reduced needle, stem and branch dry mass significantly below that induced by grass competition alone. Root:shoot ratios increased in response to the combined grass and ozone treatments. Grass competition significantly reduced soluble sugar concentrations in all ponderosa pine tissue components examined. Starch concentrations were highly variable but did not differ significantly between treatments. Ozone significantly reduced soluble sugar concentrations in fine roots and stems. In the absence of grass, ozone-treated seedlings tended to have higher tissue N concentrations than controls. In the presence of grass, ozone-treated seedlings had lower N concentrations than controls, resulting in a significant interaction between these two stresses in 1- and 2-year-old needles. Needle C:N ratios decreased in response to grass competition, as a result of increased N concentration and no change in C concentration. The opposite response was observed in ozone-treated seedlings as a result of decreased N concentrations, indicating that ozone-treated seedlings were unable to take up or retain as much nitrogen when grown in the presence of grass. We conclude that ponderosa pine seedlings are more susceptible to ozone when grown in competition with blue wild-rye grass.

Low night temperature effect on photosynthate translocation of two C4 grasses.

PubMed

Potvin, C; Strain, B R; Goeschl, J D

1985-10-01

Translocation of assimilates in plants of Echinochloa crus-galli, from Quebec and Mississippi, and of Eleusine indica from Mississippi was monitored, before and after night chilling, using radioactive tracing with the short-life isotope 11 C. Plants were grown at 28°/22°C (day/night temperatures) under either 350 or 675 μl·l -1 CO 2 . Low night temperature reduced translocation mainly by increasing the turn-over times of the export pool. E. crus-galli plants from Mississippi were the most susceptible to chilling; translocation being completely inhibited by exposure for one night to 7°C at 350 μl·l -1 CO 2 . Overall, plants from Quebec were the most tolerant to chilling-stress. For plants of all three populations, growth under CO 2 enrichment resulted in higher 11 C activity in the leaf phloem. High CO 2 concentrations also seemed to buffer the transport system against chilling injuries.

Modeled hydraulic redistribution in tree-grass, CAM-grass, and tree-CAM associations: the implications of crassulacean acid metabolism (CAM).

PubMed

Yu, Kailiang; Foster, Adrianna

2016-04-01

Past studies have largely focused on hydraulic redistribution (HR) in trees, shrubs, and grasses, and recognized its role in interspecies interactions. HR in plants that conduct crassulacean acid metabolism (CAM), however, remains poorly investigated, as does the effect of HR on transpiration in different vegetation associations (i.e., tree-grass, CAM-grass, and tree-CAM associations). We have developed a mechanistic model to investigate the net direction and magnitude of HR at the patch scale for tree-grass, CAM-grass, and tree-CAM associations at the growing season to yearly timescale. The modeling results show that deep-rooted CAM plants in CAM-grass associations could perform hydraulic lift at a higher rate than trees in tree-grass associations in a relatively wet environment, as explained by a significant increase in grass transpiration rate in the shallow soil layer, balancing a lower transpiration rate by CAM plants. By comparison, trees in tree-CAM associations may perform hydraulic descent at a higher rate than those in tree-grass associations in a dry environment. Model simulations also show that hydraulic lift increases the transpiration of shallow-rooted plants, while hydraulic descent increases that of deep-rooted plants. CAM plants transpire during the night and thus perform HR during the day. Based on these model simulations, we suggest that the ability of CAM plants to perform HR at a higher rate may have different effects on the surrounding plant community than those of plants with C3 or C4 photosynthetic pathways (i.e., diurnal transpiration).

Preventive and Therapeutic Role of Functional Ingredients of Barley Grass for Chronic Diseases in Human Beings

PubMed Central

Du, Juan; Yang, Xiaomeng; Li, Xia; Li, Ling; Zhou, Yan; Yang, Tao

2018-01-01

Barley grass powder is the best functional food that provides nutrition and eliminates toxins from cells in human beings; however, its functional ingredients have played an important role as health benefit. In order to better cognize the preventive and therapeutic role of barley grass for chronic diseases, we carried out the systematic strategies for functional ingredients of barley grass, based on the comprehensive databases, especially the PubMed, Baidu, ISI Web of Science, and CNKI, between 2008 and 2017. Barley grass is rich in functional ingredients, such as gamma-aminobutyric acid (GABA), flavonoids, saponarin, lutonarin, superoxide dismutase (SOD), K, Ca, Se, tryptophan, chlorophyll, vitamins (A, B1, C, and E), dietary fiber, polysaccharide, alkaloid, metallothioneins, and polyphenols. Barley grass promotes sleep; has antidiabetic effect; regulates blood pressure; enhances immunity; protects liver; has anti-acne/detoxifying and antidepressant effects; improves gastrointestinal function; has anticancer, anti-inflammatory, antioxidant, hypolipidemic, and antigout effects; reduces hyperuricemia; prevents hypoxia, cardiovascular diseases, fatigue, and constipation; alleviates atopic dermatitis; is a calcium supplement; improves cognition; and so on. These results support that barley grass may be one of the best functional foods for preventive chronic diseases and the best raw material of modern diet structure in promoting the development of large health industry and further reveal that GABA, flavonoids, SOD, K-Ca, vitamins, and tryptophan mechanism of barley grass have preventive and therapeutic role for chronic diseases. This paper can be used as a scientific evidence for developing functional foods and novel drugs for barley grass for preventive chronic diseases.

The interplay between the effectiveness of the grass-endophyte mutualism and the genetic variability of the host plant

PubMed Central

Gundel, Pedro E; Omacini, Marina; Sadras, Victor O; Ghersa, Claudio M

2010-01-01

Neotyphodium endophytic fungi, the asexual state of Epichloë species, protect cool-season grasses against stresses. The outcomes of Neotyphodium-grass symbioses are agronomically relevant as they may affect the productivity of pastures. It has been suggested that the mutualism is characteristic of agronomic grasses and that differential rates of gene flow between both partners’ populations are expected to disrupt the specificity of the association and, thus, the mutualism in wild grasses. We propose that compatibility is necessary but not sufficient to explain the outcomes of Neotyphodium-grass symbiosis, and advance a model that links genetic compatibility, mutualism effectiveness, and endophyte transmission efficiency. For endophytes that reproduce clonally and depend on allogamous hosts for reproduction and dissemination, we propose that this symbiosis works as an integrated entity where gene flow promotes its fitness and evolution. Compatibility between the host plant and the fungal endophyte would be high in genetically close parents; however, mutualism effectiveness and transmission efficiency would be low in fitness depressed host plants. Increasing the genetic distance of mating parents would increase mutualism effectiveness and transmission efficiency. This tendency would be broken when the genetic distance between parents is high (out-breeding depression). Our model allows for testable hypotheses that would contribute to understand the coevolutionary origin and future of the endophyte-grass mutualism. PMID:25567945

Comparison of trees and grasses for rhizoremediation of petroleum hydrocarbons.

PubMed

Cook, Rachel L; Hesterberg, Dean

2013-01-01

Rhizoremediation of petroleum contaminants is a phytoremediation process that depends on interactions among plants, microbes, and soils. Trees and grasses are commonly used for phytoremediation, with trees typically being chosen for remediation of BTEX while grasses are more commonly used for remediation of PAHs and total petroleum hydrocarbons. The objective of this review was to compare the effectiveness of trees and grasses for rhizoremediation of hydrocarbons and address the advantages of each vegetation type. Grasses were more heavily represented in the literature and therefore demonstrated a wider range of effectiveness. However, the greater biomass and depth of tree roots may have greater potential for promoting environmental conditions that can improve rhizoremediation, such as increased metabolizable organic carbon, oxygen, and water. Overall, we found little difference between grasses and trees with respect to average reduction of hydrocarbons for studies that compared planted treatments with a control. Additional detailed investigations into plant attributes that most influence hydrocarbon degradation rates should provide data needed to determine the potential for rhizoremediation with trees or grasses for a given site and identify which plant characteristics are most important.

Effects of neighbor species and distance on 2- and 4-year survival of Lehmann lovegrass and native grasses

Treesearch

Sharon H. Biedenbender; Mitchel P. McClaran; Bruce A. Roundy

2003-01-01

The relationship between Lehmann lovegrass, an invasive African grass, and native Southwestern grasses has not been fully determined. The first purpose of this study was to compare the survival of Lehmann lovegrass with two native grasses (plains lovegrass and Arizona cottontop) seeded on the Santa Rita Experimental Range in southeast Arizona in 1994. One year after...

Investigation of the Acoustics of Marine Sediments Using an Impedance Tube

DTIC Science & Technology

2008-09-30

acoustic properties of three gulf-coast species, Thalassia testudinum (turtle grass), Syringodium filiforme (manatee grass), and Halodule wrightii...effective medium. A typical result for the species Thalassia testudinum (turtle grass) is shown in Fig. 9. The two curves show plant volume fraction...the Thalassia testudinum (turtle grass) rhizomes (underground root structures) and the leaves and rhizomes of the other two species tested

Gulf Coast Deep Water Port Facilities Study. Appendix D. Adverse Environmental Effects.

DTIC Science & Technology

1973-04-01

mds 2. Thigmotropic effect of submerged structures 3. Attachment or shelter for marine organisms 4. Gain of sheltered habitat (lee of islands) 5...marshplants Bay margin marine grass, clams, snails and blue crab Grass flats marine grass, clams, snails, black drum and t other fish Open bay with tidal...surrounding area. F. CONCLUSION The most direct and easily understood effects of dredging projects on marine biota are: I) the destruction and removal of

Effect of cattle grazing, seeded grass, and an herbicide on ponderosa pine seedling survival and growth

Treesearch

Philip M. McDonald; Gary O. Fiddler

1999-01-01

On a site of above-average quality in northern California, an early shrub-forb-grass plant community was treated by artificially seeding two forage grass species at plantation age 3, cattle grazing with and without seeded grasses, and applying a soil-active chemical (Velpar). Planted ponderosa pines were part of this community. Results for a 10-year period (1988-1997)...

Investigation of the Acoustics of Marine Sediments using an Impedance Tube

DTIC Science & Technology

2007-09-30

Thalassia testudinum (turtle grass), Syringodium filiforme (manatee grass), and Halodule wrightii (shoal grass). The work led to an invited paper and...equation could be used to model sound propagation in seagrass beds as an effective medium. A typical result for the species Thalassia testudinum (turtle...analysis (Fig. 13), was found to be χleaf = 0.23. Similar results were found the Thalassia testudinum (turtle grass) rhizomes (underground root

Phenology largely explains taller grass at successful nests in greater sage-grouse.

PubMed

Smith, Joseph T; Tack, Jason D; Doherty, Kevin E; Allred, Brady W; Maestas, Jeremy D; Berkeley, Lorelle I; Dettenmaier, Seth J; Messmer, Terry A; Naugle, David E

2018-01-01

Much interest lies in the identification of manageable habitat variables that affect key vital rates for species of concern. For ground-nesting birds, vegetation surrounding the nest may play an important role in mediating nest success by providing concealment from predators. Height of grasses surrounding the nest is thought to be a driver of nest survival in greater sage-grouse ( Centrocercus urophasianus ; sage-grouse), a species that has experienced widespread population declines throughout their range. However, a growing body of the literature has found that widely used field methods can produce misleading inference on the relationship between grass height and nest success. Specifically, it has been demonstrated that measuring concealment following nest fate (failure or hatch) introduces a temporal bias whereby successful nests are measured later in the season, on average, than failed nests. This sampling bias can produce inference suggesting a positive effect of grass height on nest survival, though the relationship arises due to the confounding effect of plant phenology, not an effect on predation risk. To test the generality of this finding for sage-grouse, we reanalyzed existing datasets comprising >800 sage-grouse nests from three independent studies across the range where there was a positive relationship found between grass height and nest survival, including two using methods now known to be biased. Correcting for phenology produced equivocal relationships between grass height and sage-grouse nest survival. Viewed in total, evidence for a ubiquitous biological effect of grass height on sage-grouse nest success across time and space is lacking. In light of these findings, a reevaluation of land management guidelines emphasizing specific grass height targets to promote nest success may be merited.

Effect of pH buffer molecules on the light-induced currents from oriented purple membrane.

PubMed Central

Liu, S Y; Kono, M; Ebrey, T G

1991-01-01

The effect of pH buffers on the microsecond photocurrent component, B2, of oriented purple membranes has been studied. We found that under low salt conditions (less than 10 mM monovalent cationic salt) pH buffers can dramatically alter the waveform of the B2 component. The effect is induced by the protonation process of the buffer molecules by protons expelled from the membrane. These effects can be classified according to the charge transition upon protonation of the buffer. Buffers that carry two positive charges in their protonated form add a negative current component (N component) to B2. Almost all of the other buffers add a positive current component (P component) to B2, which is essentially a mirror image of the N component. Buffers with a pK less than 5.5 have only a small positive buffer component. The pH dependence of the buffer effect is closely related to the pK of the buffer; it requires that the buffer be in its unprotonated form. The rise time of the buffer component increases with the concentration of the buffer molecules. All the buffer effects can be inhibited by the addition of 5 mM of a divalent cation such as Ca2+. Reducing the surface potential slows down the N component but accelerates the P component without affecting the amplitude of the buffer effect significantly. Many of the buffer effects can be explained if we assume that upon protonation of the buffer by a proton expelled from the membrane by light, the buffer molecules move toward the membrane. This backward movement of buffer molecules forms a counter current very similar to that due to cations discussed in Liu, S. Y., R. Govindjee, and T. G. Ebrey. (1990. Biophys. J. 57:951-963). PMID:1883939

Coexistence of Trees and Grass: Importance of climate and fire within the tropics

NASA Astrophysics Data System (ADS)

Shuman, J. K.; Fisher, R.; Koven, C.; Knox, R. G.; Andre, B.; Kluzek, E. B.

2017-12-01

Tropical forests are characterized by transition zones where dominance shifts between trees and grasses with some areas exhibiting bistability of the two. The cause of this transition and bistability has been linked to the interacting effects of climate, vegetation structure and fire behavior. Utilizing the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), a demographic vegetation model, and the CESM ESM, we explore the coexistence of trees and grass across the tropics with an active fire regime. FATES has been updated to use a fire module based on Spitfire. FATES-Spitfire tracks fire ignition, spread and impact based on fuel state and combustion. Fire occurs within the model with variable intensity that kills trees according to the combined effects of cambial damage and crown scorch due to flame height and fire intensity. As a size-structured model, FATES allows for variable mortality based on the size of tree cohorts, where larger trees experience lower morality compared to small trees. Results for simulation scenarios where vegetation is represented by all trees, all grass, or a combination of competing trees and grass are compared to assess changes in biomass, fire regime and tree-grass coexistence. Within the forest-grass transition area there is a critical time during which grass fuels fire spread and prevents the establishment of trees. If trees are able to escape mortality a tree-grass bistable area is successful. The ability to simulate the bistability and transition of trees and grass throughout the tropics is critical to representing vegetation dynamics in response to changing climate and CO2.

Effect of Two Oil Dispersants on Larval Grass Shrimp (Palaemonetes pugio) Development.

NASA Astrophysics Data System (ADS)

Betancourt, P.; Key, P. B.; Chung, K. W.; DeLorenzo, M. E.

2015-12-01

The study focused on the effects that two oil dispersants, Corexit® EC9500A and Finasol® OSR52, have on the development of larval grass shrimp, (Palaemonetes pugio). The hypothesis was that Finasol would have a greater effect on larval grass shrimp development than Corexit. The experiment was conducted using 300 grass shrimp larvae that were 24 hours old. Each larva was exposed individually. In total, five sub-lethal concentrations were tested for each dispersant (control, 1.25, 2.50, 5.0,10.0 mg/L). The larvae were exposed for five days then transferred to clean seawater until metamorphosis into the juvenile stage. Key data measurements recorded included number of days to become juveniles, number of instars, length, dry weight, and mortality. Data from exposed shrimp was compared to the results of the control for each dispersant concentration. Corexit and Finasol exposure treatments of 5 mg/L and 10 mg/L showed significantly higher values for number of days and number of instars to reach juvenile status than values obtained from unexposed, control shrimp. Overall, mortality was higher in the Finasol treatments but the two dispersants did not respond significantly different from one another. Future studies are needed to determine the long term effects of dispersant exposure on all grass shrimp life stages and how any dispersant exposure impacts grass shrimp populations. Grass shrimp serve as excellent toxicity indicators of estuaries, and further studies will help to develop better oil spill mitigation techniques.

Impact of grass cover on the magnetic susceptibility measurements for assessing metal contamination in urban topsoil.

PubMed

Golden, Nessa; Zhang, Chaosheng; Potito, Aaron P; Gibson, Paul J; Bargary, Norma; Morrison, Liam

2017-05-01

In recent decades, magnetic susceptibility monitoring has developed as a useful technique in environmental pollution studies, particularly metal contamination of soil. This study provides the first ever examination of the effects of grass cover on magnetic susceptibility (MS) measurements of underlying urban soils. Magnetic measurements were taken in situ to determine the effects on κ (volume magnetic susceptibility) when the grass layer was present (κ grass ) and after the grass layer was trimmed down to the root (κ no grass ). Height of grass was recorded in situ at each grid point. Soil samples (n=185) were collected and measurements of mass specific magnetic susceptibility (χ) were performed in the laboratory and frequency dependence (χ fd %) calculated. Metal concentrations (Pb, Cu, Zn and Fe) in the soil samples were determined and a gradiometry survey carried out in situ on a section of the study area. Significant correlations were found between each of the MS measurements and the metal content of the soil at the p<0.01 level. Spatial distribution maps were created using Inverse Distance Weighting (IDW) and Local Indicators of Spatial Association (LISA) to identify common patterns. κ grass (ranged from 1.67 to 301.00×10 -5 SI) and κ no grass (ranged from 2.08 to 530.67×10 -5 SI) measured in situ are highly correlated [r=0.966, n=194, p<0.01]. The volume susceptibility datasets in the presence and absence of grass coverage share a similar spatial distribution pattern. This study re-evaluates in situ κ monitoring techniques and the results suggest that the removal of grass coverage prior to obtaining in situ κ measurements of urban soil is unnecessary. This layer does not impede the MS sensor from accurately measuring elevated κ in soils, and therefore κ measurements recorded with grass coverage present can be reliably used to identify areas of urban soil metal contamination. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands

Treesearch

J.D. Reeder; G.E. Schuman

2001-01-01

We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in...

EFFECTS OF FOOD AVAILABILITY ON SURVIVAL, GROWTH, AND REPRODUCTION OF THE GRASS SHRIMP PALAEMONETES PUGIO: A LABORATORY STUDY

EPA Science Inventory

Grass shrimp are abundant, ecologically important inhabitants of estuarine ecosystems; adults and embryos have been used extensively in laboratory experiments, including studies of the impacts of environmental toxicants. However, optimal laboratory feeding conditions for grass sh...

Assessing impacts of introduced aquatic species: Grass carp in large systems

NASA Astrophysics Data System (ADS)

Bain, Mark B.

1993-03-01

Introduced species have created environmental benefits and unanticipated disasters so a priori assessments of species introductions are needed for environmental management. A checklist for assessing impacts of introduced species was developed from studies of introduced species and recommendations for planning introductions. Sterile, triploid grass carp ( Ctenopharyngodon idella) are just beginning to be used as a biocontrol agent for the management of aquatic vegetation in open waterways. Potential impacts of grass carp in open systems were identified by reviewing grass carp biology relative to the impact assessment checklist. The potential consequences of introduced grass carp were reviewed for one case study. The case study demonstrated that conclusions about potential impacts and monitoring needs can be made despite incomplete information and uncertainty. Indicators of environmental impact and vulnerability of host systems were grouped into six categories: population control, hybridization, diseases and parasites, habitat alterations, biological effects, and management issues. Triploid grass carp can significantly alter habitat and biological resources through the secondary effects of reductions in aquatic vegetation. Potential impacts and significant uncertainties involve fish dispersions from plant control areas, inability to control vegetation loss, loss of diverse plant communities and their dependent species, and conflicts with human use of the water resource. Adequate knowledge existed to assess most potential consequences of releasing large numbers of triploid grass carp in Guntersville Reservoir, Alabama. However, the assessment of potential impacts indicated that moderate, incremental stockings combined with monitoring of vegetation and biological resources are necessary to control the effects of grass carp and achieve desirable, intermediate plant densities.

Headwater fish population responses to planting grass filter strips adjacent to channelized agricultural headwater streams

USDA-ARS?s Scientific Manuscript database

Grass filter strips are a widely used conservation practice in the Midwestern United States for reducing nutrient, pesticide, and sediment inputs into agricultural streams. Only a limited amount of information is available on the ecological effects of planting grass filter strips adjacent to channe...

16 CFR 1205.8 - Findings.

Code of Federal Regulations, 2011 CFR

2011-01-01

... a relatively quick and effective way to cut grass, is substantial. Riding mowers, lawn and garden tractors, hand reel mowers, trimmers and edgers, and sickle-bar mowers also provide grass-cutting services... operator to use the clutch to prevent stalling when the mower bogs down in heavy grass. On the other hand...

16 CFR 1205.8 - Findings.

Code of Federal Regulations, 2010 CFR

2010-01-01

... a relatively quick and effective way to cut grass, is substantial. Riding mowers, lawn and garden tractors, hand reel mowers, trimmers and edgers, and sickle-bar mowers also provide grass-cutting services... operator to use the clutch to prevent stalling when the mower bogs down in heavy grass. On the other hand...

Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses

PubMed Central

Silvério, Divino V.; Brando, Paulo M.; Balch, Jennifer K.; Putz, Francis E.; Nepstad, Daniel C.; Oliveira-Santos, Claudinei; Bustamante, Mercedes M. C.

2013-01-01

Changes in climate and land use that interact synergistically to increase fire frequencies and intensities in tropical regions are predicted to drive forests to new grass-dominated stable states. To reveal the mechanisms for such a transition, we established 50 ha plots in a transitional forest in the southwestern Brazilian Amazon to different fire treatments (unburned, burned annually (B1yr) or at 3-year intervals (B3yr)). Over an 8-year period since the commencement of these treatments, we documented: (i) the annual rate of pasture and native grass invasion in response to increasing fire frequency; (ii) the establishment of Brachiaria decumbens (an African C4 grass) as a function of decreasing canopy cover and (iii) the effects of grass fine fuel on fire intensity. Grasses invaded approximately 200 m from the edge into the interiors of burned plots (B1yr: 4.31 ha; B3yr: 4.96 ha) but invaded less than 10 m into the unburned plot (0.33 ha). The probability of B. decumbens establishment increased with seed availability and decreased with leaf area index. Fine fuel loads along the forest edge were more than three times higher in grass-dominated areas, which resulted in especially intense fires. Our results indicate that synergies between fires and invasive C4 grasses jeopardize the future of tropical forests. PMID:23610179

The impact of invasive grasses on the population growth of Anemone patens, a long-lived native forb.

PubMed

Williams, Jennifer L; Crone, Elizabeth E

2006-12-01

Negative impacts of invasive plants on natives have been well documented, but much less is known about whether invasive plants can cause population level declines. We used demographic models to investigate the effects of two invasive grasses on the demography and population growth of Anemone patens, a long-lived native perennial of North American grasslands. Demographic data of A. patens growing in patches characterized by Bromus inermis, Poa pratensis, or native grasses were used to parameterize integral projection models. Models based on both average conditions and those allowing for environmental stochasticity indicate that A. patens is slowly increasing in patches of native grass (lambda = 1.02) and declining in patches of invasive grasses, particularly those dominated by B. inermis (lambda = 0.93). Extinction probabilities indicate that A. patens should persist in native grass patches, but has a much higher probability of extinction in Bromus patches compared to Poa patches. While sensitivity analyses showed that survival had the biggest effect on population growth rates in all habitats, results of a Life Table Response Experiment (LTRE) revealed that slower individual growth rates in patches of invasive grasses contributed the most to the observed reduction in population growth. These results suggest that invasive grasses may cause slow declines in A. patens, despite short-term coexistence, and that controlling B. inermis only would not be sufficient to ensure A. patens persistence.

The effect of seaweed Ecklonia maxima extract and mineral nitrogen on fodder grass chemical composition.

PubMed

Ciepiela, Grażyna Anna; Godlewska, Agnieszka; Jankowska, Jolanta

2016-02-01

The objective of this study was to determine the effect of the biostimulant Kelpak and different nitrogen rates on cellulose, hemicellulose and lignin contents as well as non-structural carbohydrates in orchard grass and Braun's festulolium. The experiment was a split-plot arrangement with three replicates. It was set up at the experimental facility of the University of Natural Sciences and Humanities, Siedlce, in late April 2009. The following factors were examined: biostimulant with the trade name Kelpak SL applied at 2 dm(3) ha(-1) and a control-no biostimulant; nitrogen application rates 50 and 150 kg ha(-1) and a control (0 kg ha(-1)); pure stands of grass species grown in monoculture--orchard grass (Dactylis glomerata), cv. Amila,-Braun's festulolium (Festulolium braunii), cv. Felopa. Kelpak significantly increased non-structural carbohydrates, and increasing nitrogen rates reduced the concentration of these components in plants. Increasing nitrogen rates significantly decreased cellulose, hemicellulose, lignin and non-structural carbohydrate contents. Compared with orchard grass, Braun's festulolium proved to be of a higher nutritional value due to lower cellulose, hemicellulose and lignin contents and more non-structural carbohydrates. The aforementioned contents in the grasses differed significantly depending on the cut. Most cellulose and non-structural carbohydrates were determined in second-cut grass whereas most hemicellulose and lignin in second-cut grass.

Effects of soil water content and grass recycling on N2O emission in an urban lawn under laboratory incubation study

NASA Astrophysics Data System (ADS)

Nataningtyas, Dilin Rahayu; Morita, Shunsuke; Hatano, Ryusuke

2017-12-01

In the context of global warming, the increase of N2O gas production from the agricultural area has gained enhancing concern due to N2O is a potent greenhouse gas and an ozone depleted substance. While adding clipping grass has been accepted to replace N-fertilizer input in urban law management its effect on soil gas emission still questionable. A laboratory incubation study had been conducted to evaluate the effect of soil water content and grass recycling on greenhouse gas emission from an urban lawn. The soil samples were taken from Yurigahara Park, Sapporo, Hokkaido Japan. The 17 days at 25°C incubation study was started after adjusting soil water content to 35% and 50% with and without adding the clipping grass on soil surfaces. Greenhouse gas emissions were higher with the addition of grass, however, for NO and N2O considerably higher in 35% than 50% water content. The denitrification process was responsible for the N2O increase in this action. Soil chemical and microbial properties, pH, WEOC, NO3--N, NH4+-N and microbial biomass nitrogen (MBN) as well as N-grass content were also measured to know their correlation with N2O emission. The fine-scale heterogeneity occurred in the soil has impact on the variability of soil chemical properties that influenced the N2O emission. In the other hand, the effect of grass recycling appeared to increased soil N-inorganic contents and stimulated the N-gaseous concentration.

Evaluation of three ancillary treatments in the management of equine grass sickness.

PubMed

Fintl, C; McGorum, B C

2002-09-28

Brotizolam, acetylcysteine and aloe vera gel were evaluated as ancillary treatments for 29 cases of equine grass sickness. None of the treatments had any significant beneficial effect on the survival of the horses. However, 11 of 13 horses with mild chronic grass sickness survived solely with intensive nursing care.

Screening of Balansia epichloe-infected grass species for in situ ergot alkaloids using laser ablation electrospray ionization-mass spectrometry

USDA-ARS?s Scientific Manuscript database

The Balansia are clavicipitaceous symbiotic species associated with various species of tropical grasses. Laboratory culture procedures established that the Balansia species are often conspecific with grasses in tall fescue pastures that produced ergot alkaloids. However, any effects of hosts on the...

Sprouting Interest in Photosynthesis.

ERIC Educational Resources Information Center

Doughty, Janet

1997-01-01

Describes an alternative approach to the familiar paper cup and seed project in which students make grass heads out of nylon mesh stockings, sawdust, wire, rubber bands, plastic eyes, and grass seed. Students can observe the effects of light, sprouting rates, and the height and color of the sprouts on these grass heads. This creative activity is…

Enhanced precipitation variability decreases grass- and increases shrub-productivity

PubMed Central

Gherardi, Laureano A.; Sala, Osvaldo E.

2015-01-01

Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

[Runoff loss of soil mineral nitrogen and its relationship with grass coverage on Loess slope land].

PubMed

Zhang, Yali; Li, Huai'en; Zhang, Xingchang; Xiao, Bo

2006-12-01

In a simulated rainfall experiment on Loess slope land, this paper determined the rainfall, surface runoff and the effective depth of interaction (EDI) between rainfall and soil mineral nitrogen, and studied the effects of grass coverage on the EDI and the runoff loss of soil mineral nitrogen. The results showed that with the increase of EDI, soil nitrogen in deeper layers could be released into surface runoff through dissolution and desorption. The higher the grass coverage, the deeper the EDI was. Grass coverage promoted the interaction between surface runoff and surface soil. On the slope land with 60%, 80% and 100% of grass coverage, the mean content of runoff mineral nitrogen increased by 34.52%, 32.67% and 6.00%, while surface runoff decreased by 4.72%, 9.84% and 12.89%, and eroded sediment decreased by 83.55%, 87.11% and 89.01%, respectively, compared with bare slope land. The total runoff loss of soil mineral nitrogen on the lands with 60%, 80%, and 100% of grass coverage was 95.73%, 109.04%, and 84.05% of that on bare land, respectively. Grass cover had dual effects on the surface runoff of soil mineral nitrogen. On one hand, it enhanced the influx of soil mineral nitrogen to surface runoff, and on the other hand, it markedly decreased the runoff, resulting in the decrease of soil mineral nitrogen loss through runoff and sediment. These two distinct factors codetermined the total runoff loss of soil mineral nitrogen.

Competitive and Allelopathic Effects of Wild Rice Accessions (Oryza longistaminata) at Different Growth Stages.

PubMed

Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Zhang, Fudou; Tao, Dayun; Xu, Peng

2016-01-01

The competitive and allelopathic effects of wild rice (Oryza longistaminata) accessions on barnyard grass at different growth stages determined by days after sowing (0, 30, 60 and 90 days) were studied in greenhouse pot experiments. Wild rice accession RL159 exhibited the greatest height and tillering. The weed suppression rates of wild rice accessions OL and F1 on barnyard grass were significantly higher than for other rice accessions, with the lowest being O. sativa cultivar RD23. The highest suppression rates of OL and F1 were 80.23 and 73.96% at barnyard grass growth stages of 90 days and 60 days. At a 90 growth stage, wild rice accessions RL159 and RL169 caused 61.33 and 54.51% inhibition in barnyard grass growth, respectively. Under the same conditions, the competitive inhibition rates of OL, F1, RL159, RL169 and RL219 against barnyard grass were markedly lower than their weed suppressive effects, but were relatively similar for RD23. The allelopathic inhibition of OL and F1 on barnyard grass was significantly higher than other rice accessions. The highest allelopathic rates of OL and F1 were 60.61 and 56.87% at the 0 day growth stage. It is concluded that wild rice accessions OL and F1 exhibited the highest allelopathic activity along with moderate competitive ability against barnyard grass; wild rice accession RL159 had the highest competitive ability and moderate allelopathic activity on barnyard grass. Thus, the three wild rice accessions OL, F1 and RL159 could be used as ideal breeding materials for cultivated rice improvement.

Ultra-short-course booster is effective in recurrent grass pollen-induced allergic rhinoconjunctivitis.

PubMed

Pfaar, O; Lang, S; Pieper-Fürst, U; Astvatsatourov, A; Gerich, F; Klimek, L; Kramer, M F; Reydelet, Y; Shah-Hosseini, K; Mösges, R

2018-01-01

A relevant proportion of allergic rhinoconjunctivitis (ARC) patients experience recurrent symptoms after successfully completing allergen immunotherapy (AIT). This prospective, controlled, noninterventional study used internationally standardized instruments to determine the clinical effects of a preseasonal, ultra-short-course booster AIT on clinical outcome parameters. This two-arm study included patients aged ≥12 years with recurrent grass pollen-induced seasonal AR who had completed a successful course of any grass pollen AIT at least 5 years before enrolment. Overall, 56 patients received one preseasonal short-course booster AIT using tyrosine-absorbed grass pollen allergoids containing the adjuvant monophosphoryl lipid A (MPL ® ); 51 control patients received symptomatic medication. The combined symptom and medication score (CSMS) was recorded in the (peak) grass pollen season. Furthermore, concomitant (antiallergic) medication use, the patients' state of health, Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) results and safety/tolerability of the treatment were assessed. The CSMS in the peak grass pollen season was significantly lower in the booster AIT group (Δ=38.4%, P<.01). Moreover, significantly more patients in this group used no concomitant antiallergic medication throughout the peak grass pollen season. Twice as many patients in the booster AIT group as in the control group reported having a better state of health than in the preceding season. MiniRQLQ results showed significant differences favouring the booster AIT. The booster AIT was generally well tolerated, with only two patients reporting mild, grade 1 systemic adverse events. Booster AIT using tyrosine-absorbed allergoids containing the adjuvant MPL ® effectively prevents re-occurrence of symptoms in patients with grass pollen-induced ARC. © 2017 The Authors. Allergy Published by John Wiley & Sons Ltd.

Detrimental and Neutral Effects of a Wild Grass-Fungal Endophyte Symbiotum on Insect Preference and Performance

PubMed Central

Clement, Stephen L.; Hu, Jinguo; Stewart, Alan V.; Wang, Bingrui; Elberson, Leslie R.

2011-01-01

Seed-borne Epichloë/Neotyphodium Glenn, Bacon, Hanlin (Ascomycota: Hypocreales: Clavicipitaceae) fungal endophytes in temperate grasses can provide protection against insect attack with the degree of host resistance related to the grass—endophyte symbiotum and the insect species involved in an interaction. Few experimental studies with wild grass—endophyte symbiota, compared to endophyte-infected agricultural grasses, have tested for anti-insect benefits, let alone for resistance against more than one insect species. This study quantified the preference and performance of the bird cherry oat-aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) and the cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae), two important pests of forage and cereal grasses, on Neotyphodium-infected (E+) and uninfected (E-) plants of the wild grass Alpine timothy, Phleum alpinum L. (Poales: Poaceae). The experiments tested for both constitutive and wound-induced resistance in E+ plants to characterize possible plasticity of defense responses by a wild E+ grass. The aphid, R. padi preferred E- over E+ test plants in choice experiments and E+ undamaged test plants constitutively expressed antibiosis resistance to this aphid by suppressing population growth. Prior damage of E+ test plants did not induce higher levels of resistance to R. padi. By contrast, the beetle, O. melanopus showed no preference for E+ or E- test plants and endophyte infection did not adversely affect the survival and development of larvae. These results extend the phenomenon of variable effects of E+ wild grasses on the preference and performance of phytophagous insects. The wild grass— Neotyphodium symbiotum in this study broadens the number of wild E+ grasses available for expanded explorations into the effects of endophyte metabolites on insect herbivory. PMID:21867443

Phytophagous insect fauna tracks host plant responses to exotic grass invasion.

PubMed

Almeida-Neto, Mário; Prado, Paulo I; Lewinsohn, Thomas M

2011-04-01

The high dependence of herbivorous insects on their host plants implies that plant invaders can affect these insects directly, by not providing a suitable habitat, or indirectly, by altering host plant availability. In this study, we sampled Asteraceae flower heads in cerrado remnants with varying levels of exotic grass invasion to evaluate whether invasive grasses have a direct effect on herbivore richness independent of the current disturbance level and host plant richness. By classifying herbivores according to the degree of host plant specialization, we also investigated whether invasive grasses reduce the uniqueness of the herbivorous assemblages. Herbivorous insect richness showed a unimodal relationship with invasive grass cover that was significantly explained only by way of the variation in host plant richness. The same result was found for polyphagous and oligophagous insects, but monophages showed a significant negative response to the intensity of the grass invasion that was independent of host plant richness. Our findings lend support to the hypothesis that the aggregate effect of invasive plants on herbivores tends to mirror the effects of invasive plants on host plants. In addition, exotic plants affect specialist insects differently from generalist insects; thus exotic plants affect not only the size but also the structural profile of herbivorous insect assemblages.

Experimental demonstration of the antiherbivore effects of silica in grasses: impacts on foliage digestibility and vole growth rates

PubMed Central

Massey, Fergus P; Hartley, Sue E

2006-01-01

The impact of plant-based factors on the population dynamics of mammalian herbivores has been the subject of much debate in ecology, but the role of antiherbivore defences in grasses has received relatively little attention. Silica has been proposed as the primary defence in grasses and is thought to lead to increased abrasiveness of foliage so deterring feeding, as well as reducing foliage digestibility and herbivore performance. However, at present there is little direct experimental evidence to support these ideas. In this study, we tested the effects of manipulating silica levels on the abrasiveness of grasses and on the feeding preference and growth performance of field voles, specialist grass-feeding herbivores. Elevated silica levels did increase the abrasiveness of grasses and deterred feeding by voles. We also demonstrated, for the first time, that silica reduced the growth rates of both juvenile and mature female voles by reducing the nitrogen they could absorb from the foliage. Furthermore, we found that vole feeding leads to increased levels of silica in leaves, suggesting a dynamic feedback between grasses and their herbivores. We propose that silica induction due to vole grazing reduces vole performance and hence could contribute to cyclic dynamics in vole populations. PMID:16928631

Herbaceous Legume Encroachment Reduces Grass Productivity and Density in Arid Rangelands.

PubMed

Wagner, Thomas C; Hane, Susanne; Joubert, Dave F; Fischer, Christina

2016-01-01

Worldwide savannas and arid grasslands are mainly used for livestock grazing, providing livelihood to over a billion people. While normally dominated by perennial C4 grasses, these rangelands are increasingly affected by the massive spread of native, mainly woody legumes. The consequences are often a repression of grass cover and productivity, leading to a reduced carrying capacity. While such encroachment by woody plants has been extensively researched, studies on similar processes involving herbaceous species are rare. We studied the impact of a sustained and massive spread of the native herbaceous legume Crotalaria podocarpa in Namibia's escarpment region on the locally dominant fodder grasses Stipagrostis ciliata and Stipagrostis uniplumis. We measured tussock densities, biomass production of individual tussocks and tussock dormancy state of Stipagrostis on ten 10 m x 10 m plots affected and ten similarly-sized plots unaffected by C. podocarpa over eight consecutive years and under different seasonal rainfalls and estimated the potential relative productivity of the land. We found the percentage of active Stipagrostis tussocks and the biomass production of individual tussocks to increase asymptotically with higher seasonal rainfall reaching a maximum around 300 mm while the land's relative productivity under average local rainfall conditions reached only 40% of its potential. Crotalaria podocarpa encroachment had no effect on the proportion of productive grass tussocks, but reduced he productivity of individual Stipagrostis tussocks by a third. This effect of C. podocarpa on grass productivity was immediate and direct and was not compensated for by above-average rainfall. Besides this immediate effect, over time, the density of grass tussocks declined by more than 50% in areas encroached by C. podocarpa further and lastingly reducing the lands carrying capacity. The effects of C. podocarpa on grass productivity hereby resemble those of woody encroachers. Therefore, against the background of global change, the spread of herbaceous legumes and the underlying patterns needs to be further investigated to develop adequate counter measures for a sustainable land use.

Effects of extreme drought on specific leaf area of grassland species: A meta-analysis of experimental studies in temperate and sub-Mediterranean systems.

PubMed

Wellstein, Camilla; Poschlod, Peter; Gohlke, Andreas; Chelli, Stefano; Campetella, Giandiego; Rosbakh, Sergey; Canullo, Roberto; Kreyling, Jürgen; Jentsch, Anke; Beierkuhnlein, Carl

2017-06-01

Here, we conducted a meta-analysis of experimental drought manipulation studies using rainout shelters in five sites of natural grassland ecosystems of Europe. The single studies assess the effects of extreme drought on the intraspecific variation of the specific leaf area (SLA), a proxy of plant growth. We evaluate and compare the effect size of the SLA response for the functional groups of forbs and grasses in temperate and sub-Mediterranean systems. We hypothesized that the functional groups of grasses and forbs from temperate grassland systems have different strategies in short-term drought response, measured as adjustment of SLA, with SLA-reduction in grasses and SLA-maintenance in forbs. Second, we hypothesized that grasses and forbs from sub-Mediterranean systems do not differ in their drought response as both groups maintain their SLA. We found a significant decrease of SLA in grasses of the temperate systems in response to drought while SLA of forbs showed no significant response. Lower SLA is associated with enhanced water-use efficiency under water stress and thus can be seen as a strategy of phenotypic adjustment. By contrast, in the sub-Mediterranean systems, grasses significantly increased their SLA in the drought treatment. This result points towards a better growth performance of these grasses, which is most likely related to their strategy to allocate resources to belowground parts. The observed SLA reduction of forbs is most likely a direct drought response given that competitive effect of grasses is unlikely due to the scanty vegetation cover. We point out that phenotypic adjustment is an important driver of short-term functional plant response to climatic extremes such as drought. Differential reactions of functional groups have to be interpreted against the background of the group's evolutionary configuration that can differ between climatic zones. © 2017 John Wiley & Sons Ltd.

Effectiveness of narrow grass hedges in reducing atrazine runoff under different slope gradient conditions.

PubMed

Wang, Qinghai; Li, Cui; Chen, Chao; Chen, Jie; Zheng, Ruilun; Que, Xiaoe

2018-03-01

Atrazine is frequently detected in surface runoff and poses a potential threat to the environment. Grass hedges may minimize runoff loss of atrazine from crop fields. Therefore, the effectiveness of two grass hedges (Melilotus albus and Pennisetum alopecuroides) in controlling atrazine runoff was investigated using simulated rainfall on lands at different slope gradients (15 and 20%) in northern China. Results showed that a storm (40 mm in 1 h), occurring 4 h after atrazine application, caused a loss of 3% of the applied amount. Atrazine loss under 20% slope was significantly greater than that under 15% slope in control plots. Atrazine exports associated with the water fraction accounted for the majority of total loss. Pennisetum hedges were more efficient in controlling atrazine loss with runoff compared to Melilotus hedges. No significant difference in the capacity of grass hedges to reduce atrazine exports was observed between 15 and 20% slopes. These findings suggest grass hedges are effective in minimizing atrazine runoff in northern China, and Pennisetum hedges should be preferentially used on sloping croplands in similar climatic regions.

Grass seeding as a control for roadbank erosion.

Treesearch

A.G. Wollum

1962-01-01

Grass, seeded on a steep roadcut in western Oregon, reduced erosion but caused increased surface runoff during a 3-year period of observation. These results were obtained at H. J. Andrews Experimental Forest from a study designed to measure effectiveness of grass in controlling soil erosion from exposed roadbanks. Additional measurements for varying soil types will be...

The effects of precipitation and soil type on three invasive annual grasses in the western United States

Treesearch

Sheel Bansal; Jeremy J. James; Roger L. Sheley

2014-01-01

Multiple species of annual grasses are invading sagebrush-steppe communities throughout the western United States. Most research has focused on dominant species such as Bromus tectorum (cheatgrass), yet other, less studied annual grasses such as Taeniatherum caput-medusae (medusahead) and Ventenata dubia (ventenata) are spreading rapidly. Future precipitation regimes...

Breeding bird territory placement in riparian wet meadows in relation to invasive reed canary grass, Phalaris arundinacea

USGS Publications Warehouse

Kirsch, E.M.; Gray, B.R.; Fox, T.J.; Thogmartin, W.E.

2007-01-01

Invasive plants are a growing concern worldwide for conservation of native habitats. In endangered wet meadow habitat in the Upper Midwestern United States, reed canary grass (Phalaris arundinacea) is a recognized problem and its prevalence is more widespread than the better-known invasive wetland plant purple loosestrife (Lythrum salicaria). Although resource managers are concerned about the effect of reed canary grass on birds, this is the first study to report how common wet meadow birds use habitat in relation to reed canary grass cover and dominance. We examined three response variables: territory placement, size of territories, and numbers of territories per plot in relation to cover of reed canary grass. Territory locations for Sedge Wren (Cistothorus platensis) and Song Sparrow (Melospiza melodia) were positively associated with reed canary grass cover, while those for Common Yellowthroat (Geothlypis trichas) were not. Only Swamp Sparrow (M. georgiana) territory locations were negatively associated with reed canary grass cover and dominance (which indicated a tendency to place territories where there was no reed canary grass or where many plant species occurred with reed canary grass). Swamp Sparrow territories were positively associated with vegetation height density and litter depth. Common Yellowthroat territories were positively associated with vegetation height density and shrub cover. Song Sparrow territories were negatively associated with litter depth. Reed canary grass cover within territories was not associated with territory size for any of these four bird species. Territory density per plot was not associated with average reed canary grass cover of plots for all four species. Sedge Wrens and Song Sparrows may not respond negatively to reed canary grass because this grass is native to wet meadows of North America, and in the study area it merely replaces other tall lush plants. Avoidance of reed canary grass by Swamp Sparrows may be mediated through their preference for wet areas where reed canary grass typically does not dominate. ?? 2007, The Society of Wetland Scientists.

Phytomining Perspectives in Rehabilitation of Mining and Industrial Areas of South Ural

NASA Astrophysics Data System (ADS)

Timofeeva, S. S.; Ulrikh, D. V.; Timofeev, S. S.

2017-05-01

The ability of midland hawthorn (Crataegus laevigata (Poir)), common barberry (Berberis vulgaris), red elder (Sambucus racemosa), cinnamon rose (Rosa cinnamomea L.), couch grass (Elytrigia repens), crested wheat grass (Agropyron cristatum), meadow fescue (Festuca pratensis) and meadow grass (Poa pratensis) for phytoextraction of heavy metals from technogenic soil is proved in the article. The possibility of effective phytoextraction with the use of hawthorn and elder is shown. Maximum accumulation of zinc takes place in the surface mass of couch grass and meadow fescue. In regard to the conditions of South Ural, planting of elder and hawthorn with seeding of couch grass and meadow fescue is recommended for phytomining purposes.

The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

DOE PAGES

Yang, Yurong; Liang, Yan; Han, Xiaozhen; ...

2016-02-04

Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. Here, our study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizalmore » legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.« less

The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

PubMed Central

Yang, Yurong; Liang, Yan; Han, Xiaozhen; Chiu, Tsan-Yu; Ghosh, Amit; Chen, Hui; Tang, Ming

2016-01-01

Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation. PMID:26842958

The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yurong; Liang, Yan; Han, Xiaozhen

Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. Here, our study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizalmore » legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.« less

Seasonal, inter-annual and decadal drivers of tree and grass productivity in an Australian tropical savanna.

NASA Astrophysics Data System (ADS)

Moore, C.; Beringer, J.; Hutley, L. B.; Evans, B. J.; Tapper, N. J.; Donohue, R. J.; Exbrayat, J. F.

2016-12-01

Tree-grass savannas are a widespread biome and are highly valued for their ecosystem services. Natural or anthropogenic shifts in the savanna tree-grass ratio have wide-reaching implications for food production, timber harvesting, biodiversity, the water cycle and carbon sequestration. It is important to understand the long-term dynamics and drivers of both tree and grass productivity separately, in order to successfully manage savannas in the future. This study investigates the inter-annual variability (IAV) of tree (overstory) and grass (understory) productivity at the Howard Springs OzFlux/Fluxnet site by combining a long-term (15 year) eddy covariance flux record and DIFFUSE model estimates of tree and grass productivity inferred from satellite remote sensing. On a seasonal basis, the primary drivers of overstory and understory productivity were solar radiation in the wet season and soil moisture in the dry season, with deeper soil layers becoming more important as the dry season progressed. On an inter-annual basis, variability in the amount of annual rainfall and length of the rainy season determined soil water availability, which had a positive effect on overstory productivity and a negative effect on understory productivity. No linear trend in the tree-grass ratio was observed over the 15-year study period, indicating that woody encroachment was not occurring to a significant degree at the study site. However, the tree-grass ratio was well correlated with modes of climate variability, namely the Southern Oscillation Index. This study has provided important insight into the long-term contributions of trees and grasses to savanna productivity, along with the respective drivers of IAV. The results will contribute towards model development and building better links with remote sensing techniques in order to more comprehensively monitor savanna structure and function across space and time.

Bermuda grass as feedstock for biofuel production: a review.

PubMed

Xu, Jiele; Wang, Ziyu; Cheng, Jay J

2011-09-01

Bermuda grass is a promising feedstock for the production of fuel ethanol in the Southern United States. This paper presents a review of the significant amount of research on the conversion of Bermuda grass to ethanol and a brief discussion on the factors affecting the biomass production in the field. The biggest challenge of biomass conversion comes from the recalcitrance of lignocellulose. A variety of chemical, physico-chemical, and biological pretreatment methods have been investigated to improve the digestibility of Bermuda grass with encouraging results reported. The subsequent enzymatic hydrolysis and fermentation steps have also been extensively studied and effectively optimized. It is expected that the development of genetic engineering technologies for the grass and fermenting organisms has the potential to greatly improve the economic viability of Bermuda grass-based fuel ethanol production systems. Other energy applications of Bermuda grass include anaerobic digestion for biogas generation and pyrolysis for syngas production. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of nitrogen fertilisation rate and maturity of grass silage on methane emission by lactating dairy cows.

PubMed

Warner, D; Hatew, B; Podesta, S C; Klop, G; van Gastelen, S; van Laar, H; Dijkstra, J; Bannink, A

2016-01-01

Grass silage is typically fed to dairy cows in temperate regions. However, in vivo information on methane (CH(4)) emission from grass silage of varying quality is limited. We evaluated the effect of two rates of nitrogen (N) fertilisation of grassland (low fertilisation (LF), 65 kg of N/ha; and high fertilisation (HF), 150 kg of N/ha) and of three stages of maturity of grass at cutting: early maturity (EM; 28 days of regrowth), mid maturity (MM; 41 days of regrowth) and late maturity (LM; 62 days of regrowth) on CH(4) production by lactating dairy cows. In a randomised block design, 54 lactating Holstein-Friesian dairy cows (168±11 days in milk; mean±standard error of mean) received grass silage (mainly ryegrass) and compound feed at 80 : 20 on dry matter basis. Cows were adapted to the diet for 12 days and CH(4) production was measured in climate respiration chambers for 5 days. Dry matter intake (DMI; 14.9±0.56 kg/day) decreased with increasing N fertilisation and grass maturity. Production of fat- and protein-corrected milk (FPCM; 24.0±1.57 kg/day) decreased with advancing grass maturity but was not affected by N fertilisation. Apparent total-tract feed digestibility decreased with advancing grass maturity but was unaffected by N fertilisation except for an increase and decrease in N and fat digestibility with increasing N fertilisation, respectively. Total CH(4) production per cow (347±13.6 g/day) decreased with increasing N fertilisation by 4% and grass maturity by 6%. The smaller CH(4) production with advancing grass maturity was offset by a smaller FPCM and lower feed digestibility. As a result, with advancing grass maturity CH(4) emission intensity increased per units of FPCM (15.0±1.00 g CH(4)/kg) by 31% and digestible organic matter intake (33.1±0.78 g CH(4)/kg) by 15%. In addition, emission intensity increased per units of DMI (23.5±0.43 g CH(4)/kg) by 7% and gross energy intake (7.0±0.14% CH(4)) by 9%, implying an increased loss of dietary energy with advancing grass maturity. Rate of N fertilisation had no effect on CH(4) emissions per units of FPCM, DMI and gross energy intake. These results suggest that despite a lower absolute daily CH(4) production with a higher N fertilisation rate, CH(4) emission intensity remains unchanged. A significant reduction of CH(4) emission intensity can be achieved by feeding dairy cows silage of grass harvested at an earlier stage of maturity.

Health economic comparison of SLIT allergen and SCIT allergoid immunotherapy in patients with seasonal grass-allergic rhinoconjunctivitis in Germany.

PubMed

Verheggen, Bram G; Westerhout, Kirsten Y; Schreder, Carl H; Augustin, Matthias

2015-01-01

Allergoids are chemically modified allergen extracts administered to reduce allergenicity and to maintain immunogenicity. Oralair® (the 5-grass tablet) is a sublingual native grass allergen tablet for pre- and co-seasonal treatment. Based on a literature review, meta-analysis, and cost-effectiveness analysis the relative effects and costs of the 5-grass tablet versus a mix of subcutaneous allergoid compounds for grass pollen allergic rhinoconjunctivitis were assessed. A Markov model with a time horizon of nine years was used to assess the costs and effects of three-year immunotherapy treatment. Relative efficacy expressed as standardized mean differences was estimated using an indirect comparison on symptom scores extracted from available clinical trials. The Rhinitis Symptom Utility Index (RSUI) was applied as a proxy to estimate utility values for symptom scores. Drug acquisition and other medical costs were derived from published sources as well as estimates for resource use, immunotherapy persistence, and occurrence of asthma. The analysis was executed from the German payer's perspective, which includes payments of the Statutory Health Insurance (SHI) and additional payments by insurants. Comprehensive deterministic and probabilistic sensitivity analyses and different scenarios were performed to test the uncertainty concerning the incremental model outcomes. The applied model predicted a cost-utility ratio of the 5-grass tablet versus a market mix of injectable allergoid products of € 12,593 per QALY in the base case analysis. Predicted incremental costs and QALYs were € 458 (95% confidence interval, CI: € 220; € 739) and 0.036 (95% CI: 0.002; 0.078), respectively. Compared to the allergoid mix the probability of the 5-grass tablet being the most cost-effective treatment option was predicted to be 76% at a willingness-to-pay threshold of € 20,000. The results were most sensitive to changes in efficacy estimates, duration of the pollen season, and immunotherapy persistence rates. This analysis suggests the sublingual native 5-grass tablet to be cost-effective relative to a mix of subcutaneous allergoid compounds. The robustness of these statements has been confirmed in extensive sensitivity and scenario analyses.

Buffer Therapy for Cancer

PubMed Central

Ribeiro, Maria de Lourdes C; Silva, Ariosto S.; Bailey, Kate M.; Kumar, Nagi B.; Sellers, Thomas A.; Gatenby, Robert A.; Ibrahim-Hashim, Arig; Gillies, Robert J.

2013-01-01

Oral administration of pH buffers can reduce the development of spontaneous and experimental metastases in mice, and has been proposed in clinical trials. Effectiveness of buffer therapy is likely to be affected by diet, which could contribute or interfere with the therapeutic alkalinizing effect. Little data on food pH buffering capacity was available. This study evaluated the pH and buffering capacity of different foods to guide prospective trials and test the effect of the same buffer (lysine) at two different ionization states. Food groups were derived from the Harvard Food Frequency Questionnaire. Foods were blended and pH titrated with acid from initial pH values until 4.0 to determine “buffering score”, in mmol H+/pH unit. A “buffering score” was derived as the mEq H+ consumed per serving size to lower from initial to a pH 4.0, the postprandial pH of the distal duodenum. To differentiate buffering effect from any metabolic byproduct effects, we compared the effects of oral lysine buffers prepared at either pH 10.0 or 8.4, which contain 2 and 1 free base amines, respectively. The effect of these on experimental metastases formation in mice following tail vein injection of PC-3M prostate cancer cells were monitored with in vivo bioluminescence. Carbohydrates and dairy products’ buffering score varied between 0.5 and 19. Fruits and vegetables showed a low to zero buffering score. The score of meats varied between 6 and 22. Wine and juices had negative scores. Among supplements, sodium bicarbonate and Tums® had the highest buffering capacities, with scores of 11 and 20 per serving size, respectively. The “de-buffered” lysine had a less pronounced effect of prevention of metastases compared to lysine at pH 10. This study has demonstrated the anti-cancer effects of buffer therapy and suggests foods that can contribute to or compete with this approach to manage cancer. PMID:24371544

Effect of yeast extract addition to a mineral salts medium containing hydrolyzed plant xylan on fungal pullulan production.

PubMed

Kennedy Ii, Daniel E; West, Thomas P

2018-05-16

The ability of the fungus Aureobasidium pullulans ATCC 42023 to produce pullulan from yeast extract-supplemented xylan hydrolysates of the prairie grass prairie cordgrass was examined relative to polysaccharide and cell biomass production, yield, and pullulan content of the polysaccharide. A pullulan concentration of 11.2 g L-1 and yield of 0.79 g g-1 was produced by ATCC 42023 when grown for 168 h at 30°C on the phosphate-buffered hydrolysate supplemented with yeast extract. The highest biomass level being 8.8 g L-1 was produced by ATCC 42023 after 168 h on a yeast extract-supplemented, hydrolysate-containing complete medium lacking sodium chloride. The highest pullulan content of the polysaccharide produced by ATCC 42023 after 168 h on the hydrolysate medium supplemented with yeast extract and ammonium sulfate was 70%. The findings indicate that a polysaccharide with a high pullulan content can be produced at a relatively high yield by the fungus grown on a yeast extract-supplemented xylan hydrolysate, suggesting that pullulan could be produced using a biomass-based process.

Complexity in African savannas: Direct, indirect, and cascading effects of animal densities, rainfall and vegetation availability

PubMed Central

Leeuwis, Tim; Peel, Mike

2018-01-01

Savanna ecosystems are popular subjects for interaction studies. Multiple studies have been done on the impact of elephants on vegetation, the impact of grass and browse availability on animal densities or on competition between herbivore species. Previous studies showed that elephant densities are frequently negatively correlated with densities of tall trees, and that browse and grass availability are correlated with browser and grazer density respectively. Additionally, a competition effect between browse and grass availability has been reported. These relationships are usually analysed by testing direct relationships between e.g., herbivore densities and food availability, without addressing competition effects or other indirect effects. In this study, multiple interactions in a savanna system have been analysed simultaneously using Partial Least Square-Path Modelling (PLS-PM) using mammal and vegetation data from three different wildlife reserves in southern KwaZulu-Natal. The results showed that the processes that three separate models for the three areas provided the best understanding of the importance of the different interactions. These models suggest that elephants had a negative impact on trees, but also on grass availability. The impact is stronger when elephants are not able to migrate during the dry season. Browsers and grazers were correlated with browse and grass availability, but competition between browse and grass was not detected. This study shows that due to the complexity of the interactions in an ecosystem and differences in environmental factors, these interactions are best studied per area. PLS-PM can be a useful tool for estimating direct, indirect, and cascading effects of changing animal densities in conservation areas. PMID:29768481

Stability of exotic annual grasses following restoration efforts in southern California coastal sage scrub

Treesearch

Robert D. Cox; Edith B. Allen

2008-01-01

Restoration of semi-arid shrub ecosystems often requires control of invasive grasses but the effects of these grass-control treatments on native and exotic forbs have not been investigated adequately to assess long-term stability. In southern California, coastal sage scrub (CSS) vegetation is one semi-arid shrub community that has been invaded extensively by both...

Root and soil total carbon and nitrogen under bioenergy perennial grasses with various nitrogen rates

USDA-ARS?s Scientific Manuscript database

Information is scanty about root and soil C and N under bioenergy perennial grasses with various N fertilization rates in semiarid regions. We evaluated the effect of perennial grasses and N rates on root biomass C and N and soil total C (STC) and total N (STN) stocks at the 0-120 cm depth from 2011...

Drought and ozone stress effects on competition among selected prairie grass species and Giant Foxtail

Treesearch

Gregory A. Endress; Anton G. Endress; Louis R. Iverson; Louis R. Iverson

1999-01-01

Differential responses of species to environmental stress may interfere with restoration of prairie ecosystems or change community structure. The impact of increasing atmospheric ozone (O3) concentrations and/or low water on the growth of Andropogon gerardii Vitm. (big bluestem) and Sorghastrum nutans (L.) Nash (Indian grass), two common warm-season native grasses,...

Effects of grazing management treatment on grassland plant communities and prairie grouse habitat

Treesearch

Llewellyn L. Manske; William T. Barker; Mario E. Biondini

1988-01-01

Seasonlong grazing treatments show no benefit to grass basal cover and visual obstruction is not adequate. Pastures with one grazing period in mid season show no positive change in grass basal cover but have better visual obstruction than seasonlong. Deferred grazing decreases basal cover of warm season grasses and visual obstruction reduced to inadequate levels the...

Five-grass-pollen sublingual immunotherapy tablet for the treatment of grass-pollen-induced allergic rhinoconjunctivitis: 5 years of experience.

PubMed

Didier, Alain; Wahn, Ulrich; Horak, Friedrich; Cox, Linda S

2014-10-01

Oralair(®) (OA) (Stallergenes, Antony, France) is a unique pre- and co-seasonal 5-grass-pollen sublingual immunotherapy tablet launched in 2008, and now approved in 31 countries worldwide for the treatment of grass-pollen allergic rhinitis and rhinoconjunctivitis. OA is the first oral treatment with a consistent, well-balanced allergen extract that mimics natural exposure and sensitization. A wealth of data exists from over 5 years of clinical and real-world experience demonstrating the efficacy and safety of OA for grass-pollen-allergy treatment. OA is highly effective from the first pollen season in all patient subgroups, including children and those with comorbid mild asthma, irrespective of sensitization status and symptom severity. OA also has sustained long-term benefits for symptom control and quality of life. This article provides an overview of the pharmacodynamics and pharmacology of OA; its efficacy, safety, tolerability and cost-effectiveness for the treatment of allergic rhinitis and rhinoconjunctivitis and its role in clinical practice.

Mapping grass communities based on multi-temporal Landsat TM imagery and environmental variables

NASA Astrophysics Data System (ADS)

Zeng, Yuandi; Liu, Yanfang; Liu, Yaolin; de Leeuw, Jan

2007-06-01

Information on the spatial distribution of grass communities in wetland is increasingly recognized as important for effective wetland management and biological conservation. Remote sensing techniques has been proved to be an effective alternative to intensive and costly ground surveys for mapping grass community. However, the mapping accuracy of grass communities in wetland is still not preferable. The aim of this paper is to develop an effective method to map grass communities in Poyang Lake Natural Reserve. Through statistic analysis, elevation is selected as an environmental variable for its high relationship with the distribution of grass communities; NDVI stacked from images of different months was used to generate Carex community map; the image in October was used to discriminate Miscanthus and Cynodon communities. Classifications were firstly performed with maximum likelihood classifier using single date satellite image with and without elevation; then layered classifications were performed using multi-temporal satellite imagery and elevation with maximum likelihood classifier, decision tree and artificial neural network separately. The results show that environmental variables can improve the mapping accuracy; and the classification with multitemporal imagery and elevation is significantly better than that with single date image and elevation (p=0.001). Besides, maximum likelihood (a=92.71%, k=0.90) and artificial neural network (a=94.79%, k=0.93) perform significantly better than decision tree (a=86.46%, k=0.83).

Evaluation of the effects of dietary particle fractions on fermentation profile and concentration of microbiota in the rumen of dairy cows fed grass silage-based diets.

PubMed

Zebeli, Qendrim; Tafaj, Myqerem; Junck, Benjamin; Mansmann, Dominik; Steingass, Herbert; Drochner, Winfried

2008-06-01

The study evaluated the effects of three different theoretical particle lengths (TPL) of grass silage on the distribution of particle fractions of the diet and the resulting effects on fermentation profile and concentrations of protozoa and mixed bacterial mass in the rumen of three lactating Holstein cows fed total mixed rations (45% grass silage, 5% grass hay and 50% concentrate) ad libitum. Decreasing TPL of grass silage (long, medium, short) reduced particles retained on the 19-mm sieve of the Penn State Particle Separator, while particle fractions from 8 mm to 19 mm and smaller than 8 mm were increased. Different TPL did not affect pH and the concentration of volatile fatty acids in the rumen. However, lowering the TPL from long to medium increased significantly the bicarbonate concentration, acetate proportion and protozoal number in the rumen, whereas the proportion of bacterial protein in ruminal digesta and its amino acid concentration were significantly increased by the short TPL. For the current feeding conditions, it can be concluded that increasing the fraction of particles between 8 and 19 mm and probably even the fraction below 8 mm by decreasing TPL of grass silage do not adversely affect rumen conditions and can be beneficial in terms of optimising concentration and activity of ruminal microbiota in high-yielding dairy cows.

Effects of climate and water balance across grasslands of varying C3 and C4 grass cover

USGS Publications Warehouse

Witwicki, Dana L.; Munson, Seth M.; Thoma, David P.

2016-01-01

Climate change in grassland ecosystems may lead to divergent shifts in the abundance and distribution of C3 and C4 grasses. Many studies relate mean climate conditions over relatively long time periods to plant cover, but there is still much uncertainty about how the balance of C3and C4 species will be affected by climate at a finer temporal scale than season (individual events to months). We monitored cover at five grassland sites with co-dominant C3 and C4 grass species or only dominant C3 grass species for 6 yr in national parks across the Colorado Plateau region to assess the influence of specific months of climate and water balance on changes in grass cover. C4 grass cover increased and decreased to a larger degree than C3 grass cover with extremely dry and wet consecutive years, but this response varied by ecological site. Climate and water balance explained 10–49% of the inter-annual variability of cover of C3 and C4 grasses at all sites. High precipitation in the spring and in previous year monsoon storms influenced changes in cover of C4 grasses, with measures of water balance in the same months explaining additional variability. C3 grasses in grasslands where they were dominant were influenced primarily by longer periods of climate, while C3 grasses in grasslands where they were co-dominant with C4 grasses were influenced little by climate anomalies at either short or long periods of time. Our results suggest that future changes in spring and summer climate and water balance are likely to affect cover of both C3 and C4 grasses, but cover of C4 grasses may be affected more strongly, and the degree of change will depend on soils and topography where they are growing and the timing of the growing season.

Negative impacts of invasive plants on conservation of sensitive desert wildlife

USGS Publications Warehouse

Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.

2016-01-01

Habitat disturbance from development, resource extraction, off-road vehicle use, and energy development ranks highly among threats to desert systems worldwide. In the Mojave Desert, United States, these disturbances have promoted the establishment of nonnative plants, so that native grasses and forbs are now intermixed with, or have been replaced by invasive, nonnative Mediterranean grasses. This shift in plant composition has altered food availability for Mojave Desert tortoises (Gopherus agassizii), a federally listed species. We hypothesized that this change in forage would negatively influence the physiological ecology, immune competence, and health of neonatal and yearling tortoises. To test this, we monitored the effects of diet on growth, body condition, immunological responses (measured by gene transcription), and survival for 100 captive Mojave tortoises. Tortoises were assigned to one of five diets: native forbs, native grass, invasive grass, and native forbs combined with either the native or invasive grass. Tortoises eating native forbs had better body condition and immune functions, grew more, and had higher survival rates (>95%) than tortoises consuming any other diet. At the end of the experiment, 32% of individuals fed only native grass and 37% fed only invasive grass were found dead or removed from the experiment due to poor body conditions. In contrast, all tortoises fed either the native forb or combined native forb and native grass diets survived and were in good condition. Health and body condition quickly declined for tortoises fed only the native grass (Festuca octoflora) or invasive grass (Bromus rubens) with notable loss of fat and muscle mass and increased muscular atrophy. Bromus rubens seeds were found embedded in the oral mucosa and tongue in most individuals eating that diet, which led to mucosal inflammation. Genes indicative of physiological, immune, and metabolic functions were transcribed at lower levels for individuals fed B. rubens, indicating potential greater susceptibility to disease or other health-related problems. This study highlights the negative indirect effects of invasive grasses, such as red brome, in desert ecosystems, and provides definitive evidence of a larger negative consequence to health, survival, and ultimately population recruitment for Mojave Desert tortoises than previously understood.

Development of new techniques of using irradiation in the genetic improvement of warm season grasses and an assessment of the genetic and cytogenetic effects. Annual report, August 1, 1976--October 31, 1977. [Breeding of pearl millet and radioinduction of mutants of bermudagrasses by. gamma. irradiation of dormant rhizomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burton, G.W.; Hanna, W.W.

1977-08-01

New techniques of using irradiation in the genetic improvement of several warm season grasses are described. The economic value of radiation induced plant mutants and the genetic and cytogenetic effects of these treatments are discussed. Alterations in protein quality in pearl millet grain and improved varieties of Bermuda grass following radiation treatment are reported.

Herbaceous Forage and Selection Patterns by Ungulates across Varying Herbivore Assemblages in a South African Savanna

PubMed Central

Treydte, Anna Christina; Baumgartner, Sabine; Heitkönig, Ignas M. A.; Grant, Catharina C.; Getz, Wayne M.

2013-01-01

Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types. PMID:24358228

Climate drives shifts in grass reproductive phenology across the western USA

USGS Publications Warehouse

Munson, Seth M.; Long, A. Lexine

2016-01-01

The capacity of grass species to alter their reproductive timing across space and through time can indicate their ability to cope with environmental variability and help predict their future performance under climate change.We determined the long-term (1895–2013) relationship between flowering times of grass species and climate in space and time using herbarium records across ecoregions of the western USA.There was widespread concordance of C3 grasses accelerating flowering time and general delays for C4 grasses with increasing mean annual temperature, with the largest changes for annuals and individuals occurring in more northerly, wetter ecoregions. Flowering time was delayed for most grass species with increasing mean annual precipitation across space, while phenology–precipitation relationships through time were more mixed.Our results suggest that the phenology of most grass species has the capacity to respond to increases in temperature and altered precipitation expected with climate change, but weak relationships for some species in time suggest that climate tracking via migration or adaptation may be required. Divergence in phenological responses among grass functional types, species, and ecoregions suggests that climate change will have unequal effects across the western USA.

Rangeland -- Plant responses to elevated CO sub 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owensby, C.E.; Coyne, P.I.; Ham, J.M.

1992-01-01

Several broad conclusions which can be drawn from the work that was accomplished during the first 3-year phase of the study is described. In prairie ecosystems dominated by C{sub 4} grasses, it is likely that elevated atmospheric CO{sub 2} will increase ecosystem level productivity, with a greater increase in belowground productivity. The increased productivity will primarily result from increased water use efficiency due to the anti-transpirant action of CO{sub 2}. Fumigation chambers are directly confounded with elevated CO{sub 2} effects, in that both reduce evapotranspiration. The reduced evapotranspiration of the fumigation chamber is primarily through reduced wind speeds and reducedmore » radiation. In very dry years, fumigation chamber effects are negligible, but in years with normal precipitation, chamber effects and elevated CO{sub 2} effects are essentially equal with respect to reduced evapotranspiration effects. Increased production under elevated CO{sub 2} results in reduced nitrogen concentration in the herbage and increased fiber concentrations. Consequently, digestibility of the herbage is reduced, and microbial degradation of surface litter and soil organic matter is slowed. On the negative side, ruminant productivity will likely be reduced substantially, but increased carbon storage in the soil may buffer against future rise in atmospheric CO{sub 2}. Tallgrass prairie will not likely change greatly in botanical composition, since the C{sub 4} dominants responded to elevated CO{sub 2} more than the C{sub 3} subdominants.« less

A grass-fire cycle eliminates an obligate-seeding tree in a tropical savanna.

PubMed

Bowman, David M J S; MacDermott, Harry J; Nichols, Scott C; Murphy, Brett P

2014-11-01

A grass-fire cycle in Australian tropical savannas has been postulated as driving the regional decline of the obligate-seeding conifer Callitris intratropica and other fire-sensitive components of the regional flora and fauna, due to proliferation of flammable native grasses. We tested the hypothesis that a high-biomass invasive savanna grass drives a positive feedback process where intense fires destroy fire-sensitive trees, and the reduction in canopy cover facilitates further invasion by grass. We undertook an observational and experimental study using, as a model system, a plantation of C. intratropica that has been invaded by an African grass, gamba (Andropogon gayanus) in the Northern Territory, Australia. We found that high grass biomass was associated with reduced canopy cover and restriction of foliage to the upper canopy of surviving stems, and mortality of adult trees was very high (>50%) even in areas with low fuel loads (1 t·ha(-1)). Experimental fires, with fuel loads >10 t·ha(-1), typical of the grass-invasion front, caused significant mortality due to complete crown scorch. Lower fuel loads cause reduced canopy cover through defoliation of the lower canopy. These results help explain how increases in grass biomass are coupled with the decline of C. intratropica throughout northern Australia by causing a switch from litter and sparse perennial grass fuels, and hence low-intensity surface fires, to heavy annual grass fuel loads that sustain fires that burn into the midstorey. This study demonstrates that changes in fuel type can alter fire regimes with substantial knock-on effects on the biota.

Acute toxic effects of endosulfan sulfate on three life stages of grass shrimp, Palaemonetes pugio.

PubMed

Key, Peter B; Chung, Katy W; Venturella, John J; Shaddrick, Brian; Fulton, Michael H

2010-01-01

In this study, the toxicity of endosulfan sulfate, the primary degradation product of the insecticide endosulfan, was determined in three life stages of the grass shrimp (Palaemonetes pugio). After 96 h exposure to endosulfan sulfate, the grass shrimp adult LC50 was 0.86 microg/L (95% CI 0.56-1.31), the grass shrimp larvae LC50 was 1.64 microg/L (95% CI 1.09-2.47) and the grass shrimp embryo LC50 was 45.85 microg/L (95% CI 23.72-88.61 microg/L). This was compared to the previously published grass shrimp 96-h LC50s for endosulfan. The toxicity of the two compounds was similar for the grass shrimp life stages with adults more sensitive than larvae and embryos. The presence of sediment in 24h endosulfan sulfate-exposures raised LC50s for both adult and larval grass shrimp but not significantly. The USEPA expected environmental concentrations (EEC) for total endosulfan and endosulfan sulfate and the calculations of risk quotients (RQ) based on the more sensitive adult grass shrimp 96-h LC50 clearly show that environmental concentrations equal to acute EECs would prove detrimental to grass shrimp or other similarly sensitive aquatic organisms. These results indicate that given the persistence and toxicity of endosulfan sulfate, future risk assessments should consider the toxicity potential of the parent compound as well as this degradation product.

Feedlot manure top dressing for irrigated pasture: good agricultural practice or a health hazard?

PubMed

Bell, R G; Wilson, D B; Dew, E J

1976-11-01

Top dressing a spray-irrigated pasture of orchard-grass with 125 t/ha of overwintered beef feedlot manure almost doubled the yield of dry forage: 6353 kg/ha vs. 3578 kg/ha for the plots receiving no manure. Even at this rate of application, the manure did not contaminate the irrigated grass with enteropathogenic bacteria after irrigation. When the grass became contaminated through the use of fecally polluted irrigation water, the fecal coliforms, indicator organisms with survival characteristics similar to the salmonellae, were effectively eliminated from the grass after exposure to 65 hr of bright sunlight.

Pretreatment of grass waste using combined ionizing radiation-acid treatment for enhancing fermentative hydrogen production.

PubMed

Yang, Guang; Wang, Jianlong

2018-05-01

In this study, the combined ionizing radiation-acid pretreatment process was firstly applied to enhance hydrogen fermentation of grass waste. Results showed that the combined pretreatment synergistically enhanced hydrogen fermentation of grass waste. The SCOD and soluble polysaccharide contents of grass waste increased by 1.6 and 2.91 times after the combined pretreatment, respectively. SEM observation and crystallinity test showed the combined pretreatment effectively disrupted the grass structure. Owing to the more favorable substrate conditions, the hydrogen yield achieved 68 mL/g-dry grass added after the combined pretreatment, which was 161.5%, 112.5% and 28.3% higher than those from raw, ionizing radiation pretreated and acid pretreated grass waste, respectively. The VS removal also increased from 13.9% to 25.6% by the combined pretreatment. Microbial community analysis showed that the abundance of dominant hydrogen producing genus Clostridium sensu stricto 1 increased from 37.9% to 69.4% after the combined pretreatment, which contributed to more efficient hydrogen fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of fire on bird populations in mixed-grass prairie: Chapter 8

USGS Publications Warehouse

Johnson, Douglas H.; Knopf, F.L.; Samson, F.B.

1997-01-01

The mixed-grass prairie is one of the largest ecosystems in North America, originally covering about 69 million hectares (Bragg and Steuter 1995). Although much of the natural vegetation has been replaced by cropland and other uses (Samson and Knopf 1994, Bragg and Steuter 1995), significant areas have been preserved in national wildlife refuges, waterfowl production areas, state game management areas, and nature preserves. Mixed-grass prairie evolved with fire (Bragg 1995), and fire is frequently used as a management tool for prairie (Berkey et al. 1993). Much of the mixed-grass prairie that has been protected is managed to enhance the reproductive success of waterfowl and other gamebirds, but nongame birds now are receiving increasing emphasis. Despite the importance of the area to numerous species of birds and the aggressive management applied to many sites, relatively little is known about the effects of fire on the suitability of mixed-grass prairie for breeding birds. Several studies have examined effects of fire on breeding birds in the tallgrass prairie (e.g., Tester and Marshall 1961, Eddleman 1974, Halvorsen and Anderson 1983, Westenmeier and Buhnerkempe 1983, Zimmerman 1992, Herkert 1994), in western sagebrush grasslands (Peterson and Best 1987), and in shrubsteppe (Bock and Bock 1987). Studies of fire effects in the mixed-grass prairie are limited. Huber and Steuter (1984) examined the effects on birds during the breeding season following an early-May prescribed burn on a 122-ha site in South Dakota. They contrasted the bird populations on that site to those on a nearby 462-ha unburned site that had been lightly grazed by bison (Bison bison). Pylypec (1991) monitored breeding bird populations occurring in fescue prairies of Canada on a single 12.9-ha burned area and on an adjacent 5.6-ha unburned fescue prairie for three years after a prescribed burn. This chapter describes the effects of prescribed fire on common terrestrial birds at a mixed-grass prairie site in east-central North Dakota. Birds were censused annually during 1972-95 on seven plots subjected to various regimes of prescribed fire.

Competitive Effects of Various Grasses and Forbs on Ponderosa Pine Seedlings

Treesearch

Katherine J. Elliott; Alan S. White

1987-01-01

Competition between ponderosa pine seedlings and various grasses and forbs was studied on :I site in northern Arizona burned in 1982 by a wildfire. Two-year-old pine seedlings were planted in 3.05 x 3.05 m plots in April 1983, followed by the sowing of grass and forb seeds on the same plots in July 1983 after summer rains had begun. Predawn xylem water potential...

Plant litter effects on soil nutrient availability and vegetation dynamics: changes that occur when annual grasses invade shrub-steppe communities

Treesearch

Sheel Bansal; Roger L. Sheley; Bob Blank; Edward A. Vasquez

2014-01-01

Changes in the quantity and quality of plant litter occur in many ecosystems as they are invaded by exotic species, which impact soil nutrient cycling and plant community composition. Such changes in sagebrush-steppe communities are occurring with invasion of annual grasses (AG) into a perennial grass (PG) dominated system. We conducted a 5-year litter manipulation...

Optimal prescribed burn frequency to manage foundation California perennial grass species and enhance native flora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlsen, Tina M.; Espeland, Erin K.; Paterson, Lisa E.

Grasslands can be diverse assemblages of grasses and forbs but not much is known how perennial grass species management affects native plant diversity except in a few instances. We studied the use of late-spring prescribed burns over a span of 11 years where the perennial grass Poa secunda was the foundation species, with four additional years of measurements after the final burn. We also evaluated burn effects on P. secunda, the rare native annual forb Amsinckia grandiflora and local native and exotic species. Annual burning maintained P. secunda number, resulted in significant expansion, the lowest thatch and exotic grass cover,more » the highest percentage of bare ground, but also the lowest native forb and highest exotic forb cover. Burning approximately every 3 years maintained a lower number of P. secunda plants, allowed for expansion, and resulted in the highest native forb cover with a low exotic grass cover. Burning approximately every 5 years and the control (burned once from a wildfire) resulted in a decline in P. secunda number, the highest exotic grass and thatch cover and the lowest percentage of bare ground. P. secunda numbers were maintained up to 4 years after the final burn. And while local native forbs benefited from burning approximately every 3 years, planted A. grandiflora performed best in the control treatment. A. grandiflora did not occur naturally at the site; therefore, no seed bank was present to provide across-year protection from the effects of the burns. Thus, perennial grass species management must also consider other native species life history and phenology to enhance native flora diversity.« less

Optimal prescribed burn frequency to manage foundation California perennial grass species and enhance native flora

DOE PAGES

Carlsen, Tina M.; Espeland, Erin K.; Paterson, Lisa E.; ...

2017-06-06

Grasslands can be diverse assemblages of grasses and forbs but not much is known how perennial grass species management affects native plant diversity except in a few instances. We studied the use of late-spring prescribed burns over a span of 11 years where the perennial grass Poa secunda was the foundation species, with four additional years of measurements after the final burn. We also evaluated burn effects on P. secunda, the rare native annual forb Amsinckia grandiflora and local native and exotic species. Annual burning maintained P. secunda number, resulted in significant expansion, the lowest thatch and exotic grass cover,more » the highest percentage of bare ground, but also the lowest native forb and highest exotic forb cover. Burning approximately every 3 years maintained a lower number of P. secunda plants, allowed for expansion, and resulted in the highest native forb cover with a low exotic grass cover. Burning approximately every 5 years and the control (burned once from a wildfire) resulted in a decline in P. secunda number, the highest exotic grass and thatch cover and the lowest percentage of bare ground. P. secunda numbers were maintained up to 4 years after the final burn. And while local native forbs benefited from burning approximately every 3 years, planted A. grandiflora performed best in the control treatment. A. grandiflora did not occur naturally at the site; therefore, no seed bank was present to provide across-year protection from the effects of the burns. Thus, perennial grass species management must also consider other native species life history and phenology to enhance native flora diversity.« less

Flammulina velutipes treatment of non-sterile tall wheat grass for enhancing biodegradability and methane production.

PubMed

Kasprzycka, Agnieszka; Lalak-Kańczugowska, Justyna; Tys, Jerzy

2018-05-09

In this study fungal pretreatment of non-sterile tall wheat grass via the white rot fungi Flammulina velutipes was studied and the effect on biodegradability of lignocellulosic biomass and methane production, was evaluated. Degradation of lignin, cellulose, hemicellulose, and dry matter in non-sterile tall wheat grass during 28 days of fungal pretreatment using different inoculum ratio (0%-50%) and moisture content (MC) (45% MC, 65% MC, and 75% MC) were assessed via comparison to untreated biomass. Pretreatment with F. velutipes was most effective at 65% MC and 40% inoculum ratio, resulting in 22% lignin removal. The corresponding methane yields were 181.3 Ndm 3 ·kg VS -1 , which were 280% higher than for the untreated tall wheat grass. Copyright © 2018 Elsevier Ltd. All rights reserved.

Plant community patterns in unburned and burned blackbrush (Coleogyne ramosissima) shrublands in the Mojave Desert

USGS Publications Warehouse

Brooks, Matthew L.; Matchett, John R.

2003-01-01

The blackbrush vegetation type is dominated by Coleogyne ramossisima, which is thought to preclude the coexistence of many other plant species. Fire can remove blackbrush cover and possibly increase plant species richness and evenness. Fire also may increase the frequency and cover of alien annual grasses, thereby intensifying landscape flammability. We tested these predictions in unburned and burned (6-14 years postfire) blackbrush at 3 sites spanning the range of this vegetation type in the Mojave Desert. Species richness in unburned blackbrush was similar to published values for other vegetation types in western North America, but richness varied significantly among the 3 sites and 4 spatial scales (1, 10, 100, and 1000 m2). Richness values declined in order from annual forbs, woody perennials, herbaceous perennials, annual grasses, cacti, to perennial grasses. Fire reduced Coleogyne cover, thus boosting species evenness. In contrast, species richness decreased after burning, although the results varied among spatial scales. Total cover was unaffected by fire because cover of woody perennials decreased, while cover of annual forbs, annual grasses, herbaceous perennials, and perennial grasses increased. Native species richness and cover decreased, whereas alien richness and cover increased after burning, especially where the alien forb Erodium cicutarium was present. Fire had no effect on frequency and variable effects on cover of alien annual grasses. These results indicate that in blackbrush species richness can vary among sites and local spatial scales, and effects of fire can vary among plant life-forms and between natives and aliens.

The role of seasonal grass pollen on childhood asthma emergency department presentations.

PubMed

Erbas, B; Akram, M; Dharmage, S C; Tham, R; Dennekamp, M; Newbigin, E; Taylor, P; Tang, M L K; Abramson, M J

2012-05-01

Few studies have focused on the role of grass pollen on asthma emergency department (ED) presentations among children. None have examined whether a dose-response effect exists between grass pollen levels and these asthma exacerbations. To examine the association between increasing ambient levels of grass pollen and asthma ED presentations in children. To determine whether these associations are seen only after a thunderstorm, or whether grass pollen levels have a consistent influence on childhood asthma ED visits during the season. A short time series ecological study was conducted for asthma presentations to ED among children in Melbourne, Victoria, and grass pollen, meteorological and air quality measurements recorded during the selected 2003 period. A semi-parametric Poisson regression model was used to examine dose-response associations between daily grass pollen levels and mean daily ED attendance for asthma. A smoothed plot suggested a dose-response association. As ambient grass pollen increased to about 19 grains/m(3) , the same day risk of childhood ED presentations also increased linearly (P < 0.001). Grass pollen levels were also associated with an increased risk in asthma ED presentations on the following day (lag 1, P < 0.001). This is the first study to establish a clear relationship between increased risk of childhood asthma ED attendance and levels of ambient grass pollen below 20 grains/m(3) , independent of any impact of thunderstorm-associated asthma. These findings have important implications for patient care, such as asthma management programs that notify the general public regarding periods of high grass pollen exposure, as well as defining the timing of initiation of pollen immunotherapy. © 2012 Blackwell Publishing Ltd.

Climate change drives a northward expansion of C4 grasses in North America by the end of the century

NASA Astrophysics Data System (ADS)

Cotton, J. M.; Mosier, T. M.; Cerling, T. E.; Ehleringer, J. R.; Hoppe, K. A.; Still, C. J.

2016-12-01

C4 grasses currently cover 18% of the earth's surface and are critically important as food sources, and account for roughly 25% of terrestrial productivity. Yet in the future these patterns will change as a result of the opposing impacts of atmospheric CO2 and climate on C3 and C4 physiologies. Here, we use the carbon isotope ratio (d13C) of modern and fossil bison and mammoth tissues as a proxy for the abundance of C3 and C4 vegetation across North American habitats. We then combine stable isotope data with CMIP5 climate model simulations, and used eight different climatic predictor variables and advanced statistical techniques to model the spatial distributions of C3 and C4 grasses from today through the year 2100 for two fossil-fuel emissions scenarios. For both scenarios, our vegetation model predicts increases in C4 grass abundance of up to 50% in the northern Great Plains and moderate decreases in C4 grass abundance in the central and southern Great Plains. The overall effect of these C3/C4 distribution changes will be a decreases in the magnitude of the north-south grass gradient in the Great Plains ecoregion with the loss of the highest abundance of C4 ecosystems in the panhandles of Texas, Oklahoma and western Kansas. These results have important implications for future changes in animal and plant biodiversity, agricultural productivity, and C4 grass invasions in North America. Our study suggests that changing climates will likely start to favor C4 crops over C3 crops in the northern Great Plains, potentially influencing the nature of different grain food supplies. Additionally, changes in C3 and C4 grass distributions, including decreases in the abundance of C3 grasses in native grasslands in the northern Great Plains, could have negative effects on the fauna that feed preferentially on those C3 grasses, and may also reduce also the number of unique habitats that currently maintain high biodiversity.

Equine Grazing in Managed Subalpine Wetlands: Effects on Arthropods and Plant Structure as a Function of Habitat

NASA Astrophysics Data System (ADS)

Holmquist, Jeffrey G.; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A.

2013-12-01

Grazing management necessarily emphasizes the most spatially extensive vegetation assemblages, but landscapes are mosaics, often with more mesic vegetation types embedded within a matrix of drier vegetation. Our primary objective was to contrast effects of equine grazing on both subalpine vegetation structure and associated arthropods in a drier reed grass ( Calamagrostis muiriana) dominated habitat versus a wetter, more productive sedge habitat ( Carex utriculata). A second objective was to compare reed grass and sedge as habitats for fauna, irrespective of grazing. All work was done in Sequoia National Park (CA, USA), where detailed, long-term records of stock management were available. We sampled paired grazed and control wet meadows that contained both habitats. There were moderate negative effects of grazing on vegetation, and effects were greater in sedge than in reed grass. Conversely, negative grazing effects on arthropods, albeit limited, were greater in the drier reed grass, possibly due to microhabitat differences. The differing effects on plants and animals as a function of habitat emphasize the importance of considering both flora and fauna, as well as multiple habitat types, when making management decisions. Sedge supported twice the overall arthropod abundance of reed grass as well as greater diversity; hemipteran and dipteran taxa were particularly abundant in sedge. Given the greater grazing effects on sedge vegetation, greater habitat provision for terrestrial arthropods, and value as aquatic arthropod habitat, the wetter sedge assemblage is worthy of additional consideration by managers when planning for grazing and other aspects of land usage.

Uses of thaxtomin and thaxtomin compositions as herbicides

DOEpatents

Koivunen, Marja; Marrone, Pamela

2016-12-27

There is a need for a selective, low-risk herbicide that can be used to control weeds in cereal cultures and turf. The present invention discloses that a bacterial secondary metabolite, thaxtomin and optionally another herbicide is an effective herbicide on broadleaved, sedge and grass weeds. Thaxtomin A and structurally similar compounds can be used as natural herbicides to control the germination and growth of weeds in cereal, turf grass, Timothy grass and pasture grass cultures with no phytotoxicity to these crops. As a natural, non-toxic compound, thaxtomin can be used as a safe alternative for weed control in both conventional and organic farming and gardening systems.

Glyphosate decreases mycorrhizal colonization and affects plant-soil feedback.

PubMed

Helander, Marjo; Saloniemi, Irma; Omacini, Marina; Druille, Magdalena; Salminen, Juha-Pekka; Saikkonen, Kari

2018-06-11

Our aim was to study the effects of glyphosate, tilling practice and cultivation history on mycorrhizal colonization and growth of target (weeds) and non-target (crops) plants. Glyphosate, the world's most widely used pesticide, inhibits an enzyme found in plants but also in microbes. We examined the effects of glyphosate treatment applied in the preceding fall on growth of a perennial weed, Elymus repens (target plant) and a forage grass, Festuca pratensis (non-target plant) and their arbuscular mycorrhizal fungal (AMF) root colonization in a field pot experiment. Non-target plants were sown in the following spring. Furthermore, we tested if glyphosate effects depend on tillage or soil properties modulated by long cultivation history of endophyte symbiotic grass (E+ grass). AMF root colonization, plant establishment and growth, glyphosate residues in plants, and soil chemistry were measured. Glyphosate reduced the mycorrhizal colonization and growth of both target and non-target grasses. The magnitude of reduction depended on tillage and soil properties due to cultivation history of E+ grass. We detected glyphosate residues in weeds and crop plants in the growing season following the glyphosate treatment. Residues were higher in plants growing in no-till pots compared to conspecifics in tilled pots. These results demonstrate negative effects of glyphosate on non-target organisms in agricultural environments and grassland ecosystems. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

26 CFR 56.4911-1 - Tax on excess lobbying expenditures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... expenditure test election under section 501(h) is in effect (an “electing public charity”). An electing public... legislation through grass roots lobbying, the grass roots nontaxable amount (see paragraph (c) of this section... expenditures. For any taxable year for which the expenditure test election under section 501(h) is in effect...

26 CFR 56.4911-1 - Tax on excess lobbying expenditures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... expenditure test election under section 501(h) is in effect (an “electing public charity”). An electing public... legislation through grass roots lobbying, the grass roots nontaxable amount (see paragraph (c) of this section... expenditures. For any taxable year for which the expenditure test election under section 501(h) is in effect...

Narrow grass hedge effects on nutrient transport following swine slurry application

USDA-ARS?s Scientific Manuscript database

The effectiveness of a narrow grass hedge in reducing runoff nutrient loads following swine slurry application was examined in this study. Slurry was applied to 0.75-m wide by 4.0-m long plots established on an Aksarben silty clay loam soil located in southeast Nebraska. Manure treatments consisted ...

Interactions among resource partitioning, sampling effect, and facilitation on the biodiversity effect: a modeling approach.

PubMed

Flombaum, Pedro; Sala, Osvaldo E; Rastetter, Edward B

2014-02-01

Resource partitioning, facilitation, and sampling effect are the three mechanisms behind the biodiversity effect, which is depicted usually as the effect of plant-species richness on aboveground net primary production. These mechanisms operate simultaneously but their relative importance and interactions are difficult to unravel experimentally. Thus, niche differentiation and facilitation have been lumped together and separated from the sampling effect. Here, we propose three hypotheses about interactions among the three mechanisms and test them using a simulation model. The model simulated water movement through soil and vegetation, and net primary production mimicking the Patagonian steppe. Using the model, we created grass and shrub monocultures and mixtures, controlled root overlap and grass water-use efficiency (WUE) to simulate gradients of biodiversity, resource partitioning and facilitation. The presence of shrubs facilitated grass growth by increasing its WUE and in turn increased the sampling effect, whereas root overlap (resource partitioning) had, on average, no effect on sampling effect. Interestingly, resource partitioning and facilitation interacted so the effect of facilitation on sampling effect decreased as resource partitioning increased. Sampling effect was enhanced by the difference between the two functional groups in their efficiency in using resources. Morphological and physiological differences make one group outperform the other; once these differences were established further differences did not enhance the sampling effect. In addition, grass WUE and root overlap positively influence the biodiversity effect but showed no interactions.

Performance of vegetated swales for improving road runoff quality in a moderate traffic urban area.

PubMed

Leroy, Marie-Charlotte; Portet-Koltalo, Florence; Legras, Marc; Lederf, Franck; Moncond'huy, Vincent; Polaert, Isabelle; Marcotte, Stéphane

2016-10-01

In recent years, due to their economic and ecological advantages, green infrastructures for stormwater management have been widely implemented. The present study focused on vegetated swales and compared two vegetated covers, grassed or planted with macrophytes in order to evaluate their performance in terms of water quality improvement. These swales collected runoff of a moderately busy road (<2500vehday(-1)) in a commercial area. Twelve storm events were analyzed over a two year period with measurement of total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total hydrocarbons (THC), total phosphorous (TP), total Kjeldahl nitrogen (TKN), trace elements and 16 polycyclic aromatic hydrocarbons (PAHs). The grass cover led to poor results due to lower retention of soil particles on which trace elements and PAHs are bounded. The swales planted with macrophytes, with a deeper root system more capable of retaining soil particles, led to reductions of concentrations from 17 to 45% for trace elements such as lead, zinc and copper and 30% for the 16 PAHs in infiltrated waters. In addition, the macrophyte cover showed lower variability of pollutant concentrations in infiltrated waters compared to incoming waters. This buffering capacity is interesting to mitigate the impact of moderate peak pollution on surface water or ground water quality. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of different levels of raw and heated grass pea seed (Lathyrus sativus) on nutrient digestibility, intestinal villus morphology and growth performance of broiler chicks.

PubMed

Riasi, A; Mahdavi, A H; Bayat, E

2015-10-01

This study aimed to investigate chemical composition and effect of different levels (0%, 10% and 20%) of raw grass pea (RGP) and heat-treated (120 °C for 30 min) grass pea seed (HGP) on nutrient digestibility, dressing percentage, relative internal organ weights, intestinal villous morphology and broiler chicks' performance. A total number of 200 day-old male chicks were raised under similar condition for 10 days. On day 11, chicks were randomly assigned to five dietary treatments and four replicates of 10 birds each. The result of chemical analysis indicated that Iranian grass pea seed has low levels of total and condensed tannin, and it may be considered as a good source of protein (36.1%) and energy (17.09 kJ GE/g). Heat treatment reduced (p < 0.05) the total and condensed tannin to 21% and 78% respectively. Grass peas seed had higher levels of nitrogen-free extract, P, Na, Mg and Zn than soya bean meal. The apparent digestibility of gross energy and lipid was affected (p < 0.01) by the treatment diets, and it was the lowest after feeding 20% of HGP (p < 0.05). The relative weight of breast and pancreas (p < 0.05) was affected by treatments. Percentage weight of breast and pancreas increased (p < 0.05) after feeding high levels (20%) of RGP and HGP. Substitution of 20% of RGP and HGP increased the duodenal crypt depth (p < 0.05); however, it had no suppressive effect on villus height as the absorptive surface of intestine. The feed conversion ratio was not affected by the treatments in the total experimental period. This study showed that, although the high level of grass pea seed caused a remarkable increase in the relative weight of pancreas and decreased the apparent digestibility of gross energy and lipid, it had beneficial effect on breast relative weight. It seems that heat processing is not effective method for improving quality of Iranian grass pea seed. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

76 FR 71935 - Humboldt-Toiyabe National Forest, Carson Ranger District, Nevada and California, Bordertown to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-21

... medusahead grass and bull thistle from construction of temporary roads. Ability to reclaim temporary roads... and bulbous blue grass in the area. Potential effects to historic properties, including the National...

The Effects of High Steady State Auxin Levels on Root Cell Elongation in Brachypodium[OPEN

PubMed Central

Pacheco-Villalobos, David; Tamaki, Takayuki; Gujas, Bojan; Jaspert, Nina; Oecking, Claudia; Bulone, Vincent; Hardtke, Christian S.

2016-01-01

The long-standing Acid Growth Theory of plant cell elongation posits that auxin promotes cell elongation by stimulating cell wall acidification and thus expansin action. To date, the paucity of pertinent genetic materials has precluded thorough analysis of the importance of this concept in roots. The recent isolation of mutants of the model grass species Brachypodium distachyon with dramatically enhanced root cell elongation due to increased cellular auxin levels has allowed us to address this question. We found that the primary transcriptomic effect associated with elevated steady state auxin concentration in elongating root cells is upregulation of cell wall remodeling factors, notably expansins, while plant hormone signaling pathways maintain remarkable homeostasis. These changes are specifically accompanied by reduced cell wall arabinogalactan complexity but not by increased proton excretion. On the contrary, we observed a tendency for decreased rather than increased proton extrusion from root elongation zones with higher cellular auxin levels. Moreover, similar to Brachypodium, root cell elongation is, in general, robustly buffered against external pH fluctuation in Arabidopsis thaliana. However, forced acidification through artificial proton pump activation inhibits root cell elongation. Thus, the interplay between auxin, proton pump activation, and expansin action may be more flexible in roots than in shoots. PMID:27169463

Development of a Tool for Siting Low Impact Development in Urban Watersheds

NASA Astrophysics Data System (ADS)

Martin-Mikle, C.; de Beurs, K.; Julian, J.

2013-12-01

Low impact development (LID) -- a comprehensive land use planning and design approach with the goal of mitigating development impacts on hydrologic/nutrient cycles and ecosystems -- is increasingly being touted as an effective approach to lessen overland runoff and pollutant loadings. Examples of LIDs include riparian buffers, grassed swales, detention/retention ponds, rain gardens, green roofs and rain barrels. Broad-scale decision support tools for siting LIDs have been developed for agricultural watersheds, but are rare for urban watersheds, largely due to greater land use complexity and lack of necessary high-resolution geospatial data. Here, we develop a framework to assist city planners and water quality managers in siting LIDs in urban watersheds. One key component of this research is a framework accessible to those interested in using it. Hence, development of the framework has centered around 1) determining optimal data requirements for siting LID in an urban watershed and 2) developing a tool compatible with both open-source and commercial GIS software. We employ a wide variety of landscape metrics to evaluate the tool. A case study of the Lake Thunderbird Watershed, an urbanized watershed southeast of Oklahoma City, illustrates the effectiveness of a tool that is capable of siting LID in an urban watershed.

Establishing native grasses in a big sagebrush-dominated site: an intermediate restoration step

USGS Publications Warehouse

Huber-Sannwald, Elisabeth; Pyke, David A.

2005-01-01

Many semiarid rangelands in the Great Basin, U.S.A., are shifting dominance to woody species as a consequence of land degradation including intense livestock grazing and fire suppression. Whereas past rehabilitation efforts in Big sagebrush (Artemisia tridentata) steppes removed the shrub and added introduced forage grasses to successfully shift communities from shrublands to grasslands, current consensus is that native species should be included in restoration projects and that retention of some woody plants is desirable. We examined the potential for interseeding grasses into dense shrub communities as a precursor to thinning shrubs and releasing grasses from shrub interference. We compared seedling establishment of the native grass, Bluebunch wheatgrass (Pseudoroegneria spicata), with that of the Eurasia grass, Crested wheatgrass (Agropyron desertorum), in dense Ar. tridentata stands. Shrubs may play an important role as nurse plants for seedling establishment (reduced solar radiation, 'island of fertility' effect) but result in highly contrasting light environments and root interference for seedlings. In experimental plots, we examined effects of Ar. tridentata shade levels (0, 40, 70, and 90% reduction of solar radiation) and initial root exclusion (present/absent) on the establishment and growth of P. spicata and Ag. desertorum seedlings. With this design we evaluated the interference effects of Ar. tridentata on the two grasses and identified the most beneficial microsites for grass restoration in Ar. tridentataa??dominated communities. We predicted seedling survival and growth to be greater under moderate shade (40% reduction) and limited root competition than under no or strong shade conditions (0 and 90%) and unrestricted root interactions. Fifty to 85% of the P. spicata and Ag. desertorum seedlings survived the dry summer months of 1995 and 1996 and the intervening winter. Neither shading nor root exclusion from Ar. tridentata affected final seedling survival of either species. Seedling biomass of both grass species was negatively affected by initial root interactions with Ar. tridentata. However, the analysis of seedling biomass variability (coefficient of variation) indicated that in all shade and root-exclusion treatments, some seedlings of both species developed to large individuals to survive in Ar. tridentataa??dominated rangelands. Thus, the use of interseeding techniques shows promise for restoring herbaceous species in dense Ar. tridentata stands and should be given further consideration when shrub retention is an important consideration.

Effects of field-grown genetically modified Zoysia grass on bacterial community structure.

PubMed

Lee, Yong-Eok; Yang, Sang-Hwan; Bae, Tae-Woong; Kang, Hong-Gyu; Lim, Pyung-Ok; Lee, Hyo-Yeon

2011-04-01

Herbicide-tolerant Zoysia grass has been previously developed through Agrobacterium-mediated transformation. We investigated the effects of genetically modified (GM) Zoysia grass and the associated herbicide application on bacterial community structure by using culture-independent approaches. To assess the possible horizontal gene transfer (HGT) of transgenic DNA to soil microorganisms, total soil DNAs were amplified by PCR with two primer sets for the bar and hpt genes, which were introduced into the GM Zoysia grass by a callus-type transformation. The transgenic genes were not detected from the total genomic DNAs extracted from 1.5 g of each rhizosphere soils of GM and non-GM Zoysia grasses. The structures and diversities of the bacterial communities in rhizosphere soils of GM and non-GM Zoysia grasses were investigated by constructing 16S rDNA clone libraries. Classifier, provided in the RDP II, assigned 100 clones in the 16S rRNA gene sequences library into 11 bacterial phyla. The most abundant phyla in both clone libraries were Acidobacteria and Proteobacteria. The bacterial diversity of the GM clone library was lower than that of the non- GM library. The former contained four phyla, whereas the latter had seven phyla. Phylogenetic trees were constructed to confirm these results. Phylogenetic analyses of the two clone libraries revealed considerable difference from each other. The significance of difference between clone libraries was examined with LIBSHUFF statistics. LIBSHUFF analysis revealed that the two clone libraries differed significantly (P〈0.025), suggesting alterations in the composition of the microbial community associated with GM Zoysia grass.

Effects of an invasive grass on the demography of the Caribbean cactus Harrisia portoricensis: Implications for cacti conservation

NASA Astrophysics Data System (ADS)

Rojas-Sandoval, Julissa; Meléndez-Ackerman, Elvia

2012-05-01

The impact of exotic species around the world is among the primary threats to the conservation and management of rare and endangered species. In this work we asked whether or not the presence of the African grass Megathyrsus maximus on Mona Island was associated with negative impacts on the demography of the endangered Caribbean cactus Harrisia portoricensis. To address this question we performed field observations where we compared demographic data collected at un-manipulated areas invaded by Megathyrsus with un-manipulated areas non-invaded by this exotic grass. Additionally, demographic data were also collected in areas in which we removed the exotic grass biomass using two alternative treatments: complete and partial grass removal. Results demonstrated that the presence of Megathyrsus has negative effects on demographic parameters of Harrisia at various stages throughout its life cycle. In general, the survival, growth, and reproduction of Harrisia plants were depressed under the presence of Megathyrsus. Growth and survival of seedlings and juveniles of Harrisia were more impacted by the presence of Megathyrsus than adult performance and seedling recruitment only occurred in areas with grass absence. Our combined results suggest that modifications of the micro-environment by the presence of Megathyrsus may add an additional level of vulnerability to the persistence of Harrisia, and as such this factor must be considered when designing conservation strategies for this endangered species. This study highlights the need for a greater emphasis on understanding the interactions between invasive grass species and native cacti, and the importance of such information in designing conservation strategies for cacti species elsewhere.

Costs of Producing Biomass from Riparian Buffer Strips

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turhollow, A.

2000-09-01

Nutrient runoff from poultry litter applied to agricultural fields in the Delmarva Peninsula contributes to high nutrient loadings in Chesapeake Bay. One potential means of ameliorating this problem is the use of riparian buffer strips. Riparian buffer strips intercept overland flows of water, sediments, nutrients, and pollutants; and ground water flows of nutrients and pollutants. Costs are estimated for three biomass systems grown on buffer strips: willow planted at a density of 15,300 trees/ha (6200 trees/acre); poplar planted at a density of 1345 trees/ha (545 trees/acre); and switchgrass. These costs are estimated for five different scenarios: (1) total economic costs,more » where everything is costed [cash costs, noncash costs (e.g., depreciation), land rent, labor]; (2) costs with Conservation Reserve Program (CRP) payments (which pays 50% of establishment costs and an annual land rent); (3) costs with enhanced CRP payments (which pays 95% of establishment costs and an annual payment of approximately 170% of land rent for trees and 150% of land rent for grasses); (4) costs when buffer strips are required, but harvest of biomass is not required [costs borne by biomass are for yield enhancing activities (e.g., fertilization), harvest, and transport]; and (5) costs when buffer strips are required. and harvest of biomass is required to remove nutrients (costs borne by biomass are for yield enhancing activities and transport). CRP regulations would have to change to allow harvest. Delivered costs of willow, poplar, and switchgrass [including transportation costs of $0.38/GJ ($0.40/million Btu) for switchgrass and $0.57/GJ ($0.60/million Btu) for willow and poplar] at 11.2 dry Mg/ha-year (5 dry tons/acre-year) for the five cost scenarios listed above are [$/GJ ($million BIN)]: (1) 3.30-5.45 (3.45-5.75); (2) 2.30-3.80 (2.45-4.00); (3) 1.70-2.45 (1.80-2.60); (4) l-85-3.80 (1.95-4.05); and (5) 0.80-1.50 (0.85-1.60). At yields of 15.7 to 17.9 GJ/ha-year (7 to 8 dry tons/acre-year), lower willow and poplar establishment costs, transportation costs of $0.30 to $0.45/GJ ($0.30-$0.50/million Btu), and lower willow and poplar harvest costs, total economic costs for willow (19-year stand life), poplar, and switchgrass are $2.35 to $2.6O/GJ ($2.50 to $2.75/million Btu). The potential production of biomass from riparian buffer strips in the Delmarva Peninsula ranges from 190,000 to 380,000 Mg (2 10,000 to 420,000 dry tons) per year.« less

Prairie and turf buffer strips for controlling runoff from paved surfaces.

PubMed

Steinke, K; Stier, J C; Kussow, W R; Thompson, A

2007-01-01

Eutrophication of surface waters due to nonpoint source pollution from urban environments has raised awareness of the need to decrease runoff from roads and other impervious surfaces. These concerns have led to precautionary P application restrictions on turf and requirements for vegetative buffer strips. The impacts of two plant communities and three impervious/pervious surface ratios were assessed on runoff water quality and quantity. A mixed forb/grass prairie and a Kentucky bluegrass (Poa pratensis L.) blend were seeded and runoff was monitored and analyzed for total volume, total P, soluble P, soluble organic P, bioavailable P, total suspended solids, and total organic suspended solids. Mean annual runoff volumes, all types of mean annual P nutrient losses, and sediment loads were not significantly affected by treatments because over 80% of runoff occurred during frozen soil conditions. Total P losses from prairie and turf were similar, averaging 1.96 and 2.12 kg ha(-1) yr(-1), respectively. Vegetation appeared to be a likely contributor of nutrients, particularly from prairie during winter dormancy. When runoff occurred during non-frozen soil conditions turf allowed significantly (P < or = 0.10) lower runoff volumes compared with prairie vegetation and the 1:2 and 1:4 impervious/pervious surface ratios had less runoff than the 1:1 ratio (P < or = 0.05). In climates where the majority of runoff occurs during frozen ground conditions, vegetative buffers strips alone are unlikely to dramatically reduce runoff and nutrient loading into surface waters. Regardless of vegetation type or size, natural nutrient biogeochemical cycling will cause nutrient loss in surface runoff waters, and these values may represent baseline thresholds below which values cannot be obtained.

Ensiling and hydrothermal pretreatment of grass: consequences for enzymatic biomass conversion and total monosaccharide yields

PubMed Central

2014-01-01

Background Ensiling may act as a pretreatment of fresh grass biomass and increase the enzymatic conversion of structural carbohydrates to fermentable sugars. However, ensiling does not provide sufficient severity to be a standalone pretreatment method. Here, ensiling of grass is combined with hydrothermal treatment (HTT) with the aim of improving the enzymatic biomass convertibility and decrease the required temperature of the HTT. Results Grass silage (Festulolium Hykor) was hydrothermally treated at temperatures of 170, 180, and 190°C for 10 minutes. Relative to HTT treated dry grass, ensiling increased the solubilization of dry matter (DM) during HTT and gave increased glucan content, but lower lignin in the insoluble fiber fraction. Ensiling improved glucose yields in the enzymatic hydrolysis of the washed solid fiber fraction at the lower HTT temperatures. At 170°C glucose yield improved from 17 to 24 (w/w)% (45 to 57% cellulose convertibility), and at 180°C glucose yield improved from 22 to 29 (w/w)% (54 to 69% cellulose convertibility). Direct HTT of grass at 190°C gave the same high glucose yield as for grass silage (35 (w/w)% (77% cellulose convertibility)) and improved xylan yields (27% xylan convertibility). The effect of ensiling of grass prior to HTT improved the enzymatic conversion of cellulose for HTT at 170 and 180°C, but the increased glucose release did not make up for the loss of water soluble carbohydrates (WSC) during ensiling. Overall, sugar yields (C6 + C5) were similar for HTT of grass and grass silage at both 170 and 180°C, but at 190°C the overall sugar yield was better for HTT of dry grass. Conclusions This study unequivocally establishes that ensiling of grass as a biomass pretreatment method comes with a loss of WSC. The loss of WSC by ensiling is not necessarily compensated for by providing a lower temperature requirement for HTT for high enzymatic monosaccharide release. However, ensiling can be an advantageous storage method prior to grass processing. PMID:25024743

Performance Enhancement of Small Molecular Solar Cells by Bilayer Cathode Buffer.

PubMed

Sun, Qinjun; Zhao, Huanbin; Zhou, Miao; Gao, Liyan; Hao, Yuying

2016-04-01

An effective composite bilayer cathode buffer structure is proposed for use in small molecular solar cells. CsF was doped in Alq3 to form the first cathode buffer, leading to small serial resistances. BCP was used as the second cathode buffer to block the holes to the electrode. The optimized bilayer cathode buffer significantly increased the short circuit and fill factor of devices. By integrating this bilayer cathode buffer, the CuPc/C60 small molecular heterojunction cell exhibited a power conversion efficiency of up to 0.8%, which was an improvement of 56% compared to a device with only the Alq3 cathode buffer. Meanwhile, the bilayer cathode buffer still has a good protective effect on the performance of the device.

Designing bioenergy crop buffers to mitigate nitrous oxide emissions and water quality impacts from agriculture

NASA Astrophysics Data System (ADS)

Gopalakrishnan, G.; Negri, C. M.

2010-12-01

There is a strong societal need to evaluate and understand the environmental aspects of bioenergy production, especially due to the significant increases in production mandated by many countries, including the United States. Bioenergy is a land-based renewable resource and increases in production are likely to result in large-scale conversion of land from current uses to bioenergy crop production; potentially causing increases in the prices of food, land and agricultural commodities as well as disruption of ecosystems. Current research on the environmental sustainability of bioenergy has largely focused on the potential of bioenergy crops to sequester carbon and mitigate greenhouse gas (GHG) emissions and possible impacts on water quality and quantity. A key assumption in these studies is that bioenergy crops will be grown in a manner similar to current agricultural crops such as corn and hence would affect the environment similarly. This study presents a systems approach where the agricultural, energy and environmental sectors are considered as components of a single system, and bioenergy crops are used to design multi-functional agricultural landscapes that meet society’s requirements for food, energy and environmental protection. We evaluate the production of bioenergy crop buffers on marginal land and using degraded water and discuss the potential for growing cellulosic bioenergy crops such as miscanthus and switchgrass in optimized systems such that (1) marginal land is brought into productive use; (2) impaired water is used to boost yields (3); clean freshwater is left for other uses that require higher water quality; and (4) feedstock diversification is achieved that helps ecological sustainability, biodiversity, and economic opportunities for farmers. The process-based biogeochemical model DNDC was used to simulate crop yield, nitrous oxide production and nitrate concentrations in groundwater when bioenergy crops were grown in buffer strips adjacent to corn fields. The bioenergy crops used in this study were miscanthus, switchgrass and native prairie grasses. Results indicated that growing bioenergy crops in buffer strips mitigated nutrient runoff and reduced nitrate concentrations in groundwater to below EPA’s mandated drinking water limit (10 mg/l). Additionally, nitrous oxide emissions in these systems were reduced by 50-90% when compared to corn fields without the bioenergy buffer strips. While all the bioenergy crop buffers had significant positive environmental benefits, switchgrass performed the best with respect to minimizing nutrient runoff and nitrous oxide emissions. The findings of this research have important implications with respect to land management for agriculture and bioenergy.

Composition and design of vegetative filter strips instrumental in improving water quality by mass reduction of suspended sediment, nutrients and Escherichia coli in overland flows in eastern escarpment of Mau Forest, Njoro River Watershed, Kenya

PubMed Central

Olilo, C. O.; Onyando, J. O.; Moturi, W. N.; Muia, A. W.; Roegner, Amber F.; Ogari, Z.; Ombui, P. N.; Shivoga, W. A.

2016-01-01

This study assessed the effect of vegetative filter strip (VFS) in removal of suspended sediment (SS), total nitrogen, total phosphorus and Escherichia coli (E. coli) in overland flow to improve receiving water quality standards. Four and half kilograms of cowpat manure was applied to the model pasture 14 m beyond the edge of vegetated filter strip (VFS) comprising 10-m Napier grass draining into 20-m Kikuyu grass (VFS II), 10-m Kikuyu grass draining into 20-m Napier grass (VFS III) and native grass mixture of Couch–Buffel (VFS I-control). Overland flow water samples were collected from the sites at positions 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25 and 30 m along the length of VFSs. E. coli removal by Napier grass VFS was on the order of log unit, which provided an important level of protection and reduced surface-flow concentrations of E. coli to below the 200 (CFU 100 mL−1) recommended water quality standards, but not for nutrients and SS. The Napier grass showed highest efficiency (99.6 %), thus outperforming both Kikuyu grass (85.8 %) and Couch–Buffel grasses VFS (67.9 ± 4.2 %) in removing E. coli from overland flow. The low-level efficiency of native Couch–Buffel grasses in reducing E. coli in overland flow was because of preferential flow. Composition and design of VFS was instrumental and could be applied with a high potential of contracting the uncertainty in improving water quality standards through mass reduction of SS, nutrients and E. coli load in watersheds. PMID:28133624

Belowground impacts of perennial grass cultivation for sustainable biofuel feedstock production in the tropics

DOE PAGES

Sumiyoshi, Yudai; Crow, Susan E.; Litton, Creighton M.; ...

2016-07-08

Perennial grasses can sequester soil organic carbon (SOC) in sustainably managed biofuel systems, directly mitigating atmospheric CO 2 concentrations while simultaneously generating biomass for renewable energy. Our objective was to quantify SOC accumulation and identify the primary drivers of belowground C dynamics in a zero-tillage production system of tropical perennial C4 grasses grown for biofuel feedstock in Hawaii. Specifically, the quantity, quality, and fate of soil C inputs were determined for eight grass accessions – four varieties each of napier grass and guinea grass. Carbon fluxes (soil CO 2 efflux, aboveground net primary productivity, litterfall, total belowground carbon flux, rootmore » decay constant), C pools (SOC pool and root biomass), and C quality (root chemistry, C and nitrogen concentrations, and ratios) were measured through three harvest cycles following conversion of a fallow field to cultivated perennial grasses. A wide range of SOC accumulation occurred, with both significant species and accession effects. Aboveground biomass yield was greater, and root lignin concentration was lower for napier grass than guinea grass. Structural equation modeling revealed that root lignin concentration was the most important driver of SOC pool: varieties with low root lignin concentration, which was significantly related to rapid root decomposition, accumulated the greatest amount of SOC. Roots with low lignin concentration decomposed rapidly, but the residue and associated microbial biomass/by-products accumulated as SOC. In general, napier grass was better suited for promoting soil C sequestration in this system. Further, high-yielding varieties with low root lignin concentration provided the greatest climate change mitigation potential in a ratoon system. By understanding the factors affecting SOC accumulation and the net greenhouse gas trade-offs within a biofuel production system will aid in crop selection to meet multiple goals toward environmental and economic sustainability.« less

Long-term effects of seeding after wildfire on vegetation in Great Basin shrubland ecosystems

USGS Publications Warehouse

Knutson, Kevin C.; Pyke, David A.; Wirth, Troy A.; Arkle, Robert S.; Pilliod, David S.; Brooks, Matthew L.; Chambers, Jeanne C.; Grace, James B.

2014-01-01

1. Invasive annual grasses alter fire regimes in shrubland ecosystems of the western USA, threatening ecosystem function and fragmenting habitats necessary for shrub-obligate species such as greater sage-grouse. Post-fire stabilization and rehabilitation treatments have been administered to stabilize soils, reduce invasive species spread and restore or establish sustainable ecosystems in which native species are well represented. Long-term effectiveness of these treatments has rarely been evaluated. 2. We studied vegetation at 88 sites where aerial or drill seeding was implemented following fires between 1990 and 2003 in Great Basin (USA) shrublands. We examined sites on loamy soils that burned only once since 1970 to eliminate confounding effects of recurrent fire and to assess soils most conducive to establishment of seeded species. We evaluated whether seeding provided greater cover of perennial seeded species than burned–unseeded and unburned–unseeded sites, while also accounting for environmental variation. 3. Post-fire seeding of native perennial grasses generally did not increase cover relative to burned–unseeded areas. Native perennial grass cover did, however, increase after drill seeding when competitive non-natives were not included in mixes. Seeding non-native perennial grasses and the shrub Bassia prostrata resulted in more vegetative cover in aerial and drill seeding, with non-native perennial grass cover increasing with annual precipitation. Seeding native shrubs, particularly Artemisia tridentata, did not increase shrub cover or density in burned areas. Cover of undesirable, non-native annual grasses was lower in drill seeded relative to unseeded areas, but only at higher elevations. 4. Synthesis and applications. Management objectives are more likely to be met in high-elevation or precipitation locations where establishment of perennial grasses occurred. On lower and drier sites, management objectives are unlikely to be met with seeding alone. Intensive restoration methods such as invasive plant control and/or repeated sowings after establishment failures due to weather may be required in subsequent years. Managers might consider using native-only seed mixtures when establishment of native perennial grasses is the goal. Post-fire rehabilitation provides a land treatment example where long-term monitoring can inform adaptive management decisions to meet future objectives, particularly in arid landscapes where recovery is slow.

Effects of fire and emergency seeding on hillslope erosion in southern California chaparral

Treesearch

Pete Wohlgemuth; Jan Beyers; C.D. Wakeman; S.G. Conard

2002-01-01

Catastrophic wildfires can set the stage for massive postfire erosion and sedimentation in southern California chaparral ecosystems with the onset of heavy winter rainstorms. As a mitigation measure, land managers have typically used grass seeding as a standard emergency rehabilitation technique. However, the effectiveness of grass seeding as a watershed protection...

Abiotic factors affect the recruitment and biomass of perennial grass and evergreen shrub seedlings in denuded areas of Patagonian Monte rangelands.

PubMed

Bosco, Tomás; Bertiller, Mónica Beatriz; Carrera, Analía Lorena

2018-07-15

Assessing the ability of key species to cope with environmental stresses in disturbed areas is an important issue for recovery of degraded arid ecosystem. Our objective was to evaluate the effect of soil moisture, exposure to UV radiation, and presence/absence of litter with different chemistry on soil N, recruitment and biomass of seedlings of perennial grass (Poa ligularis and Nassella tenuis) and evergreen shrub species (Atriplex lampa and Larrea divaricata) in denuded areas. We carried out a microcosm experiment with soil blocks (28 cm depth) sowed with seeds of the target species, subjected to different levels of litter type (perennial grass-evergreen shrub mixture, evergreen shrub mixture, and no litter), UV radiation (near ambient and reduced UV), and soil water (high: 15-25% and low 5-15%). Periodically, during 6 months, we assessed soil-N (total and inorganic) at two depths and species seedling recruitment at microcosms. Additionally, emerged seedlings of each species were transplanted to individual pots containing soil and subjected to the same previous factors during 12 months. Then, all plants were harvested and biomass assessed. Only inorganic soil-N at the upper soil varied among treatments increasing with the presence of evergreen shrub litter, exposure to ambient UV, and high soil water. Inorganic soil-N, promoted by near ambient UV and high soil water, had a positive effect on recruitment of perennial grasses and A. lampa. Both litter types promoted the recruitment of perennial grasses. Evergreen shrub litter and high soil water promoted the recruitment of L. divaricata. Seedling biomass of perennial grasses increased with high soil water and reduced UV. Ambient UV had positive or null effects on biomass of evergreen shrub seedlings. High soil water increased biomass of L. divaricata seedlings. We concluded that soil water appeared as the most limiting factor for seedling recruitment of all species whereas inorganic soil N limited the recruitment of the small-seeded perennial grasses and A. lampa. Ambient UV had negative effects on seedling biomass of perennial grasses. These complex relationships among abiotic factors and seed and plant traits should be taken into account when planning management actions after disturbances. Copyright © 2018 Elsevier Ltd. All rights reserved.

Persistence and Effective Half-Life of Chemical Warfare Agent VX on Grass Foliage

DTIC Science & Technology

2017-08-01

obtain results applicable to VX- contaminated battlefields. The Effective Half-Life of VX on grass foliage was determined as the net effect of factors...Soldiers on VX- contaminated battlefields. 15. SUBJECT TERMS Chemical warfare agent (CWA) Agent–plant Echinochloa crus-galli Foliage Effective Half...The use of either trade or manufacturers ’ names in this report does not constitute an official endorsement of any commercial products. This report may

Stream water responses to timber harvest: Riparian buffer width effectiveness

Treesearch

Barton D. Clinton

2011-01-01

Vegetated riparian buffers are critical for protecting aquatic and terrestrial processes and habitats in southern Appalachian ecosystems. In this case study, we examined the effect of riparian buffer width on stream water quality following upland forest management activities in four headwater catchments. Three riparian buffer widths were delineated prior to cutting; 0m...

Determination of the acute toxicity of isoniazid to three invasive carp species and rainbow trout in static exposures

USGS Publications Warehouse

Schreier, Theresa M.; Hubert, Terrance D.

2015-01-01

Three invasive fishes of considerable concern to aquatic resource managers are the Hypophthalmichthys nobilis (bighead carp),Hypophthalmichthys molitrix (silver carp), and Ctenopharyngodon idella (grass carp), collectively known as Asian carps. There is a need for an effective chemical control agent for Asian carps. Isoniazid was identified as a potential toxicant for grass carp. The selective toxicity of isoniazid to grass carp was verified as a response to an anecdotal report received in 2013. In addition, the toxicity of isoniazid to bighead carp, silver carp, and Oncorhynchus mykiss (rainbow trout) was evaluated. Isoniazid was not toxic to grass carp at the reported anecdotal concentration, which was 13 milligrams per liter. Isoniazid (130 milligrams per liter) was not selectively toxic to bighead carp, silver carp, or grass carp when compared to rainbow trout.

Determination of Flow Resistance Coefficient for Vegetation in Open Channel: Laboratory study

NASA Astrophysics Data System (ADS)

Aliza Ahmad, Noor; Ali, ZarinaMd; Arish, Nur Aini Mohd; Munirah Mat Daud, Azra; Fatin Amirah Alias, Nur

2018-04-01

This study focused on determination of flow resistances coefficient for grass in an open channel. Laboratory works were conducted to examine the effects of varying of roughness elements on the flume to determine flow resistance coefficient and also to determine the optimum flow resistance with five different flow rate, Q. Laboratory study with two type of vegetation which are Cow Grass and Pearl Grass were implementing to the bed of a flume. The roughness coefficient, n value is determine using Manning’s equation while Soil Conservation Services (SCS) method was used to determine the surface resistance. From the experiment, the flow resistance coefficient for Cow Grass in range 0.0008 - 0.0039 while Pearl Grass value for the flow resistance coefficient are in between 0.0013 - 0.0054. As a conclusion the vegetation roughness value in open channel are depends on density, distribution type of vegetation used and physical characteristic of the vegetation itself

Effect of forage conservation method on ruminal lipid metabolism and microbial ecology in lactating cows fed diets containing a 60:40 forage-to-concentrate ratio.

PubMed

Halmemies-Beauchet-Filleau, A; Kairenius, P; Ahvenjärvi, S; Crosley, L K; Muetzel, S; Huhtanen, P; Vanhatalo, A; Toivonen, V; Wallace, R J; Shingfield, K J

2013-04-01

The effect of forage conservation method on ruminal lipid metabolism and microbial ecology was examined in 2 complementary experiments in cows. Treatments comprised fresh chopped grass, barn-dried hay, or untreated (UTS) or formic acid-treated silage (FAS) prepared from the same grass sward. Preparation of conserved forages coincided with the collection of samples from cows offered fresh grass. In the first experiment, 5 multiparous Finnish Ayrshire cows (229 d in milk) were used to compare the effects of feeding diets based on grass followed by hay during 2 consecutive 14-d periods separated by a 5-d transition during which extensively wilted grass was fed. In the second experiment, 5 multiparous Finnish Ayrshire cows (53 d in milk) were assigned to 1 of 2 blocks and allocated treatments according to a replicated 3×3 Latin square design with 14-d periods to compare the effects of hay, UTS, and FAS. Cows received 7 or 9 kg/d of the same concentrate in experiments 1 and 2, respectively. Conservation of grass by drying, but not ensiling, decreased forage fatty acid content primarily due to losses of 18:2n-6 and 18:3n-3. Compared with grass, feeding hay had no effect on dry matter intake (DMI), rumen pH, or fermentation characteristics, other than increasing ammonia content, but lowered whole-tract organic matter and fiber digestibility (experiment 1). Relative to hay, silage increased DMI, rumen volatile fatty acid (VFA) concentrations, and molar proportions of butyrate, and decreased molar acetate proportions (experiment 2). Compared with UTS, FAS increased DMI, had no effect on rumen ammonia or VFA concentrations, but tended to lower rumen pH and the molar ratio of lipogenic to glucogenic VFA. Conservation method had no substantial effect on ruminal or whole-tract digestibility coefficients. Compared with fresh grass and silages, hay decreased lipolysis and biohydrogenation (BH) of dietary unsaturates in the rumen, resulting in similar flows of 18:2n-6 and 18:3n-3, but lower amounts of trans-11 18:1 and Δ11,13 18:2 at the omasum. The extent of silage fermentation had minimal influence on ruminal lipid metabolism. Treatments were not associated with changes in the relative abundance of specific bacteria known to be capable of BH or rumen protozoal numbers. In conclusion, conservation method altered forage lipids, the extent of lipolysis and BH in the rumen, and the flow of fatty acids at the omasum, in the absence of substantial changes in ruminal Butyrivibrio populations. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Grass-legume mixtures sustain strong yield advantage over monocultures under cool maritime growing conditions over a period of 5 years.

PubMed

Helgadóttir, Áslaug; Suter, Matthias; Gylfadóttir, Thórey Ó; Kristjánsdóttir, Thórdís A; Lüscher, Andreas

2018-05-22

Grassland-based livestock systems in cool maritime regions are commonly dominated by grass monocultures receiving relatively high levels of fertilizer. The current study investigated whether grass-legume mixtures can improve the productivity, resource efficiency and robustness of yield persistence of cultivated grassland under extreme growing conditions over a period of 5 years. Monocultures and mixtures of two grasses (Phleum pratense and Festuca pratensis) and two legumes (Trifolium pratense and Trifolium repens), one of which was fast establishing and the other temporally persistent, were sown in a field trial. Relative abundance of the four species in the mixtures was systematically varied at sowing. The plots were maintained under three N levels (20, 70 and 220 kg N ha-1 year-1) and harvested twice a year for five consecutive years. Yields of individual species and interactions between all species present were modelled to estimate the species diversity effects. Significant positive diversity effects in all individual years and averaged across the 5 years were observed. Across years, the four-species equi-proportional mixture was 71 % (N20: 20 kg N ha-1 year-1) and 51 % (N70: 70 kg N ha-1 year-1) more productive than the average of monocultures, and the highest yielding mixture was 36 % (N20) and 39 % (N70) more productive than the highest yielding monoculture. Importantly, diversity effects were also evident at low relative abundances of either species group, grasses or legumes in the mixture. Mixtures suppressed weeds significantly better than monocultures consistently during the course of the experiment at all N levels. The results show that even in the less productive agricultural systems in the cool maritime regions grass-legume mixtures can contribute substantially and persistently to a more sustainable agriculture. Positive grass-legume interactions suggest that symbiotic N2 fixation is maintained even under these marginal conditions, provided that adapted species and cultivars are used.

Impact of grassland management regimes on bacterial endophyte diversity differs with grass species.

PubMed

Wemheuer, F; Wemheuer, B; Kretzschmar, D; Pfeiffer, B; Herzog, S; Daniel, R; Vidal, S

2016-04-01

Most plant species are colonized by endophytic bacteria. Despite their importance for plant health and growth, the response of these bacteria to grassland management regimes is still not understood. Hence, we investigated the bacterial community structure in three agricultural important grass species Dactylis glomerata L., Festuca rubra L. and Lolium perenne L. with regard to fertilizer application and different mowing frequencies. For this purpose, above-ground plant material was collected from the Grassland Management Experiment (GrassMan) in Germany in September 2010 and 2011. DNA was extracted from surface-sterilized plant tissue and subjected to 16S rRNA gene PCRs. Endophytic community structures were assessed by denaturing gradient gel electrophoresis (DGGE)-based analysis of obtained PCR products. DGGE fingerprints revealed that fertilizer application significantly altered the endophytic communities in L. perenne and F. rubra but not in D. glomerata. Although no direct effect of mowing was observed, mowing frequencies in combination with fertilizer application had a significant impact on endophyte bacterial community structures. However, this effect was not observed for all three grass species in both years. Therefore, our results showed that management regimes changed the bacterial endophyte communities, but this effect was plant-specific and varied over time. Endophytic bacteria play an important role in plant health and growth. However, studies addressing the influence of grassland management regimes on these bacteria in above-ground plant parts are still missing. In this study, we present first evidence that fertilizer application significantly impacted bacterial community structures in three agricultural important grass species, whereas mowing had only a minor effect. Moreover, this effect was plant-specific and thus not visible for all grass species in each year. Consequently, this study sheds new light into the complex interaction of microbes and plants. © 2016 The Society for Applied Microbiology.

E-learning for grass-roots emergency public health personnel: Preliminary lessons from a national program in China.

PubMed

Xu, Wangquan; Jiang, Qicheng; Qin, Xia; Fang, Guixia; Hu, Zhi

2016-07-19

In China, grass-roots emergency public health personnel have relatively limited emergency response capabilities and they are constantly required to update their professional knowledge and skills due to recurring and new public health emergencies. However, professional training, a principal solution to this problem, is inadequate because of limitations in manpower and financial resources at grass-roots public health agencies. In order to provide a cost-effective and easily expandable way for grass-roots personnel to acquire knowledge and skills, the National Health Planning Commission of China developed an emergency response information platform and provided trial access to this platform in Anhui and Heilongjiang provinces in China. E-learning was one of the modules of the platform and this paper has focused on an e-learning pilot program. Results indicated that e-learning had satisfactorily improved the knowledge and ability of grass-roots emergency public health personnel, and the program provided an opportunity to gain experience in e-course design and implementing e-learning. Issues such as the lack of personalized e-courses and the difficulty of evaluating the effectiveness of e-learning are topics for further study.

Variable effects of fungal endophyte-infected grasses on the performance of pestiferous aphids

USDA-ARS?s Scientific Manuscript database

The extent of fungal endophyte (Neotyphodium) based antibiosis resistance in temperate grasses (Lolium spp., Hordeum spp.) to five pestiferous aphid species (Rhopalosiphum padi (L.), Diuraphis noxia (Kurdjumov), Schizaphis graminum (Rondani), Metopolophium dirhodum (Walker), Aploneura lentisci (Pass...

Ecophysiological aspects of the interactions between Bromus kopetdaghensis and two nurse shrubs, Astragalus meschedensis and Acantholimon raddeanam in a semiarid rangeland.

PubMed

Jankju, M; Maghamnia, A

2010-07-01

Plant-plant interactions are known as the main biotic drivers of the vegetation dynamics. Therefore, understanding such processes is beneficial for the applied vegetation management. The aim of this research was to investigate the type and intensity of plant-plant interaction during the time course of a growth season. We studied ecophysiological aspects of facilitation and competition between two aridland shrubs, A. meschedensis Bunge and A. raddeanam Czernjak and one perennial grass, B. kopetdaghensis Krasch. Soil and plant sampling were carried out for shrubs and the grass that were either growing alone or the grass was growing under the canopy of shrubs. In Spring (May), soil humidity weight was higher under the shrubs+grass than the grass-only site. By the beginning of Summer (July) grass consumed the common soil water and rapidly terminated its yearly growth. Therefore, in August and September, soil humidity weight was lower under the shrubs+grass than shrub-only sites. Photosynthesis rate of B. kopetdaghensis was sharply reduced from the beginning towards the end of growth season, but was not varied between the different plant combinations. Leaf proline measurement in July indicated higher stress for B. kopetdaghensis that were growing under shrubs than those of open areas. In conclusion, we found facilitation effects of shrubs on the grass at the early times of growth season, but it shifted into the competition for water during summer times. The outcome of plant interaction was positive for the grass but negative for the shrubs, especially A. meschedensis.

A grass–fire cycle eliminates an obligate-seeding tree in a tropical savanna

PubMed Central

Bowman, David M J S; MacDermott, Harry J; Nichols, Scott C; Murphy, Brett P

2014-01-01

A grass–fire cycle in Australian tropical savannas has been postulated as driving the regional decline of the obligate-seeding conifer Callitris intratropica and other fire-sensitive components of the regional flora and fauna, due to proliferation of flammable native grasses. We tested the hypothesis that a high-biomass invasive savanna grass drives a positive feedback process where intense fires destroy fire-sensitive trees, and the reduction in canopy cover facilitates further invasion by grass. We undertook an observational and experimental study using, as a model system, a plantation of C. intratropica that has been invaded by an African grass, gamba (Andropogon gayanus) in the Northern Territory, Australia. We found that high grass biomass was associated with reduced canopy cover and restriction of foliage to the upper canopy of surviving stems, and mortality of adult trees was very high (>50%) even in areas with low fuel loads (1 t·ha−1). Experimental fires, with fuel loads >10 t·ha−1, typical of the grass-invasion front, caused significant mortality due to complete crown scorch. Lower fuel loads cause reduced canopy cover through defoliation of the lower canopy. These results help explain how increases in grass biomass are coupled with the decline of C. intratropica throughout northern Australia by causing a switch from litter and sparse perennial grass fuels, and hence low-intensity surface fires, to heavy annual grass fuel loads that sustain fires that burn into the midstorey. This study demonstrates that changes in fuel type can alter fire regimes with substantial knock-on effects on the biota. PMID:25505543

Herbivore impacts to the moss layer determine tundra ecosystem response to grazing and warming.

PubMed

Gornall, Jemma L; Woodin, Sarah J; Jónsdóttir, Ingibjörg S; Van der Wal, Rene

2009-10-01

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.

Phytoremediation of disturbed lands in Polar Regions of Russia

NASA Astrophysics Data System (ADS)

Shamsutdinova, Evgeniya

2017-04-01

In the Northern regions the problem of restoration of disturbed lands as a result of anthropogenic activities is particularly acut. A large role for the success of native plants to take hold and re-establish themselves is to allow the natural process to work without human intervention. However observation shows that low reserves of available moisture, poor soil nutrients, exposure to wind and water erosion make impossible of a complete restoration of lands due to natural revegetation. One of the methods used to minimize the effect of these factors is the phytoremediation. Research on the Pelyatinskom gas condensate field in the Taimyr Dolgano-Nenets municipal district revealed the efficacy of biological remediation of awnless brome, wildrye siberian, red fescue and kentucky bluegrass. Geobotanical studies of the tailings fields in Yakutia showed that for the phytoremediation of tailings of alluvial deposits of diamonds slough grass can be successfully used, and on the dumps of coal deposits with a high degree of survival of the willow, poplar, larch, alder stand and pine. Development of technology for remediation of placer gold deposits of the Komsomol mine and Bilibino in Chukotka has shown the effectiveness of sowing common oat, wildrye and larch. The study of the experience of recultivation on objects of the "Transneft-Baltic" in the North-Western Federal district allowed us to select as the recommended mixtures of species: meadow fescue, cocksfoot, timothy grass, white and alsike clover and alfalfa. The multicomponent mixture of red fescue, awnless brome, meadow fescue, timothy grass, couch grass, kentucky bluegrass, beckman's grass were successfully used at the mine of the Bovanenkovo oil and gas condensate field. On the technological grounds of the complex pumping station in the Yamalo-Nenets Autonomous area willows were planted. Pine and willow trees were planted on quarry workings in the Northern taiga of Western Siberia land .Planting of pines has shown its effectiveness in quarries and construction materials in the vicinity of Syktyvkar. In the course of practical activities carried out in the area of Monchegorsk, on the copper-Nickel plant, the possibility of using willow for remediation of metal contaminated land is also being discussed, as this plant is efficient for phytoextraction. For land reclamation along the pipeline messoyakha-Noril'sk in the region of the drilling rigs on the Taimyr Peninsula and industrial tailings of the Norilsk industrial district, it is recommended to use the red and sheep fescue, Alpine and meadow bluegrass, arctophila reddish, meadow foxtail. In biological recultivation of disturbed territories on the Yamal Peninsula to accelerate the growth and development of plants peat textiles with sowing of red and meadow fescue, awnless brome, timothy grass, couch grass, kentucky bluegrass, beckman's grass were used. The technology of phytoremediation is widely used in Alaska. For recultivation of zinc mines in Northwest Alaska glaucous spear grass, blue joint grass, slough grass were used. The positive effect of Alaska red fescue and ryegrass multiflorous on degradation of hydrocarbons in contaminated soils was also studied. To clean the territory of Alaska from the polychlorinated biphenyls arctic willow and spruce were used.

Leakage effects in n-GaAs MESFET with n-GaAs buffer layer

NASA Technical Reports Server (NTRS)

Wang, Y. C.; Bahrami, M.

1983-01-01

Whereas improvement of the interface between the active layer and the buffer layer has been demonstrated, the leakage effects can be important if the buffer layer resistivity is not sufficiently high and/or the buffer layer thickness is not sufficiently small. It was found that two buffer leakage currents exist from the channel under the gate to the source and from drain to the channel in addition to the buffer leakage resistance between drain and source. It is shown that for a 1 micron gate-length n-GaAs MESFET, if the buffer layer resistivity is 12 OHM-CM and the buffer layer thickness h is 2 microns, the performance of the device degrades drastically. It is suggested that h should be below 2 microns.

The Interplay between Feedback and Buffering in Cellular Homeostasis.

PubMed

Hancock, Edward J; Ang, Jordan; Papachristodoulou, Antonis; Stan, Guy-Bart

2017-11-22

Buffering, the use of reservoirs of molecules to maintain concentrations of key molecular species, and negative feedback are the primary known mechanisms for robust homeostatic regulation. To our knowledge, however, the fundamental principles behind their combined effect have not been elucidated. Here, we study the interplay between buffering and negative feedback in the context of cellular homeostasis. We show that negative feedback counteracts slow-changing disturbances, whereas buffering counteracts fast-changing disturbances. Furthermore, feedback and buffering have limitations that create trade-offs for regulation: instability in the case of feedback and molecular noise in the case of buffering. However, because buffering stabilizes feedback and feedback attenuates noise from slower-acting buffering, their combined effect on homeostasis can be synergistic. These effects can be explained within a traditional control theory framework and are consistent with experimental observations of both ATP homeostasis and pH regulation in vivo. These principles are critical for studying robustness and homeostasis in biology and biotechnology. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of Introduced Grasses, Grazing and Fire on Regional Biogeochemistry in Hawaii

NASA Astrophysics Data System (ADS)

Elmore, A. J.; Asner, G. P.

2003-12-01

African grasses introduced for grazing have expanded in geographic extent in mesic tropical systems of Hawaii and other regions of the world. Grassland expansion leads to increases in fire frequency, speeding woodland and forest destruction at greater geographic scales than occurs with grazing alone. At Pu'uwa'awa'a Ranch, Hawaii, restoration of the native woodland habitat has become a critical objective following the introduction and dominance of the African grass species Pennisetum clandestinum and P. setaceum. Grazing and grass-fueled fires have destroyed over 60% of the original forest. To stabilize these communities, managers must balance the combined effects of grazing and fire. Grazing reduces the recruitment success of native tropical trees, but grazing also reduces fire risk by moderating grass fuel conditions and restricting the extent and density of the most flammable grass species. Our study focuses on two questions: (1) What grazing intensity is necessary to change the fire conditions of a region given in situ soil and precipitation conditions? (2) Have long-term grazing conditions altered soil carbon and nitrogen stocks? We used high resolution imaging spectrometer data to measure photosynthetic and non-photosynthetic vegetation cover, analysis of soil carbon and nitrogen stocks, and measurements of plant community composition along gradients in grazing intensity. P. setaceum, the more flammable alien grass, was dominant where grazing intensity was low and at lower elevations where precipitation is low. The less flammable grass, P. clandestinum, occurred in regions of high grazing intensity and higher precipitation. Grazing influenced the dominance of P. setaceum and P. clandestinum only where precipitation and soil characteristics were suitable for both grasses to occur. At suitable sites, grazing reduced fire conditions through a species sift towards P. clandestinum. Soil carbon and nitrogen stocks decreased with grazing intensity, which was correlated with the fractional cover of P. setaceum. Soil carbon also increased with precipitation. These results show how grazing impacts fire conditions and soil chemistry through changes in species composition, and not through removal of carbon inputs (direct removal of biomass).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Voris, P.; Cataldo, D.A.; Garland, T.R.

An evaluation of the terrestrial transport, transformations and ecological effects of phosphorus (red phosphorus-butyl rubber (RP/BR)), smoke/obscurant was performed to characterize the effects on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of representative of soils of those sites; and (3) soil microbiological communities. The influence and interactions of smoke/obscurant concentration relative humidity and wind speed was assessed. Toxicity symptoms for plants from repeated or a single exposure included leaf tip burn, leaf curl, leaf abscission and drop, floral abortion, chlorosis, neucrotic spotting, wilting, dessication and dieback for ponderosa pine,more » short needle pine, sagebrush, a native grass (Blando Brome) and bushbean. Soils data suggest an increase in the mobility of selected trace elements after exposure; however, this effect appears to be ameliorated with time. This phenomenon is influenced by soil type, which is a reflection of the buffering capacity of the exposed soil (i.e., Burbank, Quallayute, Shawano, and Yamac) as well as the concentration and duration of exposure. Increased mobility of trace elements is also evidenced in the trace element content of plants grown on soils after exposure to RP/BR smoke. Soil Microbial Community effects show a reduction in the production of nitrate after soil is exposed to RP/BR smoke. This indicates a reduction in ammonium oxidizing bacterial populations, specifically Nitrosomonas and probably Nitrobacter. For the most part most of the plant, soil and soil microbial effects are transient.« less

Rangeland -- Plant responses to elevated CO{sub 2}. Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owensby, C.E.; Coyne, P.I.; Ham, J.M.

1992-10-01

Several broad conclusions which can be drawn from the work that was accomplished during the first 3-year phase of the study is described. In prairie ecosystems dominated by C{sub 4} grasses, it is likely that elevated atmospheric CO{sub 2} will increase ecosystem level productivity, with a greater increase in belowground productivity. The increased productivity will primarily result from increased water use efficiency due to the anti-transpirant action of CO{sub 2}. Fumigation chambers are directly confounded with elevated CO{sub 2} effects, in that both reduce evapotranspiration. The reduced evapotranspiration of the fumigation chamber is primarily through reduced wind speeds and reducedmore » radiation. In very dry years, fumigation chamber effects are negligible, but in years with normal precipitation, chamber effects and elevated CO{sub 2} effects are essentially equal with respect to reduced evapotranspiration effects. Increased production under elevated CO{sub 2} results in reduced nitrogen concentration in the herbage and increased fiber concentrations. Consequently, digestibility of the herbage is reduced, and microbial degradation of surface litter and soil organic matter is slowed. On the negative side, ruminant productivity will likely be reduced substantially, but increased carbon storage in the soil may buffer against future rise in atmospheric CO{sub 2}. Tallgrass prairie will not likely change greatly in botanical composition, since the C{sub 4} dominants responded to elevated CO{sub 2} more than the C{sub 3} subdominants.« less

The effects of forest residual debris disposal on perennial grass emergence, growth, and survival in a ponderosa pine ecotone

Treesearch

Darin J. Law; Peter F. Kolb

2007-01-01

Soil surface conditions can have profound effects on plant seedling emergence and subsequent seedling survival. To test the hypothesis that different soil-surface treatments with logging residue affect range grass seedling emergence and survival, 6 alternative forest-residual treatments were established in the summer of 1998 following thinning of mature trees from...

Hydraulic lift as a determinant of tree-grass coexistence on savannas.

PubMed

Yu, Kailiang; D'Odorico, Paolo

2015-09-01

The coexistence of woody plants and grasses in savannas is determined by a complex set of interacting factors that determine access to resources and demographic dynamics, under the control of external drivers and vegetation feedbacks with the physical environment. Existing theories explain coexistence mainly as an effect of competitive relations and/or disturbances. However, theoretical studies on the way facilitative interactions resulting from hydraulic lift affect tree-grass coexistence and the range of environmental conditions in which savannas are stable are still lacking. We investigated the role of hydraulic lift in the stability of tree-grass coexistence in savannas. To that end, we developed a new mechanistic model that accounts for both competition for soil water in the shallow soil and fire-induced disturbance. We found that hydraulic lift favors grasses, which scavenge the water lifted by woody plants. Thus, hydraulic lift expands (at the expenses of woodlands) the range of environmental conditions in which savannas are stable. These results indicate that hydraulic lift can be an important mechanism responsible for the coexistence of woody plants and grasses in savannas. Grass facilitation by trees through the process of hydraulic lift could allow savannas to persist stably in mesic regions that would otherwise exhibit a forest cover. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Positive versus negative environmental impacts of tree encroachment in South Africa

NASA Astrophysics Data System (ADS)

Grellier, Séraphine; Ward, David; Janeau, Jean-Louis; Podwojewski, Pascal; Lorentz, Simon; Abbadie, Luc; Valentin, Christian; Barot, Sébastien

2013-11-01

Woody plant encroachment in grasslands is a worldwide phenomenon. Despite many studies, the consequences of woody plant encroachment on sub-canopy vegetation and soil properties are still unclear. To better understand the impacts of trees on grassland properties we examined the following questions using a mountainous sub-tropical grassland of South Africa encroached by an indigenous tree, Acacia sieberiana as a case study: (1) Do trees increase sub-canopy herbaceous diversity, quality and biomass and soil nitrogen content? (2) Do large trees have a stronger effect than medium-sized trees on grass and soil properties? (3) Does the impact of trees change with the presence of livestock and position of trees in a catena? We studied grass and non-graminoid species diversity and biomass, grass quality and soil properties during the wet season of 2009. Nitrogen in grass leaves, soil cation exchange capacity and calcium and magnesium ion concentrations in the soil increased under tall Acacia versus open areas. Medium-sized Acacia decreased the gross energy content, digestibility and neutral detergent fibre of grasses but increased the species richness of non-graminoids. Tall and medium Acacia trees were associated with the presence of Senecio inaequidens, an indigenous species that is toxic to horses and cattle. The presence of livestock resulted in a decrease in herbaceous root biomass and an increase in soil carbon and leaf biomass of grass under Acacia. Tree position in the catena did not modify the impact of trees on the herbaceous layer and soil properties. For management of livestock we recommend retaining tall Acacia trees and partially removing medium-sized Acacia trees because the latter had negative effects on grass quality.

Assessment of grass root effects on soil piping in sandy soils using the pinhole test

NASA Astrophysics Data System (ADS)

Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

2017-10-01

Soil piping is an important land degradation process that occurs in a wide range of environments. Despite an increasing number of studies on this type of subsurface erosion, the impact of vegetation on piping erosion is still unclear. It can be hypothesized that vegetation, and in particular plant roots, may reduce piping susceptibility of soils because roots of vegetation also control concentrated flow erosion rates or shallow mass movements. Therefore, this paper aims to assess the impact of grass roots on piping erosion susceptibility of a sandy soil. The pinhole test was used as it provides quantitative data on pipeflow discharge, sediment concentration and sediment discharge. Tests were conducted at different hydraulic heads (i.e., 50 mm, 180 mm, 380 mm and 1020 mm). Results showed that the hydraulic head was positively correlated with pipeflow discharge, sediment concentration and sediment discharge, while the presence of grass roots (expressed as root density) was negatively correlated with these pipeflow characteristics. Smaller sediment concentrations and sediment discharges were observed in root-permeated samples compared to root-free samples. When root density exceeds 0.5 kg m- 3, piping erosion rates decreased by 50% compared to root-free soil samples. Moreover, if grass roots are present, the positive correlation between hydraulic head and both sediment discharge and sediment concentration is less pronounced, demonstrating that grass roots become more effective in reducing piping erosion rates at larger hydraulic heads. Overall, this study demonstrates that grass roots are quite efficient in reducing piping erosion rates in sandy soils, even at high hydraulic head (> 1 m). As such, grass roots may therefore be used to efficiently control piping erosion rates in topsoils.

Differential effect of buffering agents on the crystallization of gemcitabine hydrochloride in frozen solutions.

PubMed

Patel, Mehulkumar; Munjal, Bhushan; Bansal, Arvind K

2014-08-25

The purpose of this study was to evaluate the differential effect of buffering agents on the crystallization of gemcitabine hydrochloride (GHCl) in frozen solutions. Four buffering agents, viz. citric acid (CA), malic acid (MA), succinic acid (SA) and tartaric acid (TA) were selected and their effect on GHCl crystallization was monitored using standard DSC and low temperature XRD. Onset of GHCl crystallization during heating run in DSC was measured to compare the differential effect of buffering agents. Glass transition temperature (Tg'), unfrozen water content in the freeze concentrate and crystallization propensity of the buffering agents was also determined for mechanistic understanding of the underlying effects. CA and MA inhibited while SA facilitated crystallization of GHCl even at 25 mM concentration. Increasing the concentration enhanced their effect. However, TA inhibited GHCl crystallization at concentrations <100mM and facilitated it at concentrations ≥100 mM. Lyophilization of GHCl with either SA or TA yielded elegant cakes, while CA and MA caused collapse. Tg' failed to explain the inhibitory effects of CA, MA and TA as all buffering agents lowered the Tg' of the system. Differential effect of buffering agents on GHCl crystallization could be explained by consideration of two opposing factors: (i) their own crystallization tendency and (ii) unfrozen water content in the freeze concentrate. In conclusion, it was established that API crystallization in frozen solution is affected by the type and concentration of the buffering agents. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of Residential Scale Biofuel Boilers and Fuels

NASA Astrophysics Data System (ADS)

Chandrasekaran, Sriraam R.

The objectives of this study were to: 1) characterize commercially available wood pellets and wood chips for basic properties such as calorific, ash, moisture contents; 2) analyze elements and ions and other possible contamination during the pellet manufacturing processes; 3) characterize the chemical and thermo-chemical property of grass pellets for their combustion potential; 4) characterize the emissions from 6 different residential scale boiler/furnace appliances burning grass and wood pellets; 5) characterize the emitted particulate matter for toxic and marker species with respect to combustion appliance and combustion conditions; and 6) determine the effects of the biomass fuel properties of 5 different grass pellets on particulate and gaseous emissions from a single type of boiler. The results from characterization of wood pellets and chips indicated that the wood pellet samples generally meet the quality standards. However, there are some samples that would fail the ash content requirements. Only the German standards have extensive trace element limits. Most of the samples would meet these standards, but some samples failed to meet these standards based on their lead, arsenic, cadmium, and copper concentrations. It is likely that inclusion of extraneous materials such as painted or pressure treated lumber led to the observed high concentrations. Given increasing use of pellets and chips as a renewable fuel, standards for the elemental composition of commercial wood pellets and chips are needed in United States to avoid the inclusion of extraneous materials. Such standards would reduce the environmental impact of toxic species that would be released when the wood is burned. Grass pellets were characterized for chemical and thermochemical properties. Switch grass pellets were studied for it thermal degradation process under inert and oxidizing atmosphere using TGA. The thermal degradation of grass pellet measured the activation energy and pre-exponential factors for switch grass decomposition. Two major losses occurred due to volatilization of cellulose, hemicelluloses, and lignin and burning or slow oxidation of residual char. The parameters were high for oxidative environment indicating high temperature sensitivity of the charcoal formation reaction. There was a substantial effect of heating rate on the mass loss and mass loss rate. The TG curve shifted to higher temperature ranges on increasing the heating rate. In both pyrolyzing and oxidizing conditions, average combustion and devolatlization rates increased. Emissions measurements and efficiency estimation were conducted on six commercially available residential scale appliances that utilize different technologies including direct combustion, gasification, lambda control, or fixed air flow rates that were designed to burn low ash wood (less than 1%). The grass has high ash and chlorine content producing more PM and chlorinated hydrocarbons including dioxins and furans. The results also indicated that the air supply and geometry of the furnace, and the type of furnace are also major influencing factors that affect the pollutant formation. To determine the effect of fuel properties on emissions formation, gaseous and particulate characterization was conducted of six fuels that include five different grass pellets types with ash content ranging from 3% to 13% and a premium wood pellet with ash content 0.6% on a boiler. Emissions from grass pellets were found to be higher than wood pellets and the PM; SO2 and NOx emissions were strongly related to the fuel properties such as ash content, sulfur and nitrogen content, respectively. CO emissions that indicate the completeness of reactions were higher for grass pellets and were strongly correlated to PAHs emissions. The PCDD/F emission was clearly a function of chlorine content of the fuel. A strong correlation existed between levoglucosan and PM2.5 concentrations indicated that levoglucosan is also a molecular marker for grass pellet combustion. All of the emissions were found to be higher for grass pellets when compared to the wood pellets and are higher at high loads than at low loads. These results show that the grass pellets cannot be used as a fuel in current generation wood pellet systems. It will be necessary to design systems that effectively deal with the higher ash and chlorine content if grass pellets are to be a significant fuel for home heating. (Abstract shortened by UMI.)

Little effect of HSP90 inhibition on the quantitative wing traits variation in Drosophila melanogaster.

PubMed

Takahashi, Kazuo H

2017-02-01

Drosophila wings have been a model system to study the effect of HSP90 on quantitative trait variation. The effect of HSP90 inhibition on environmental buffering of wing morphology varies among studies while the genetic buffering effect of it was examined in only one study and was not detected. Variable results so far might show that the genetic background influences the environmental and genetic buffering effect of HSP90. In the previous studies, the number of the genetic backgrounds used is limited. To examine the effect of HSP90 inhibition with a larger number of genetic backgrounds than the previous studies, 20 wild-type strains of Drosophila melanogaster were used in this study. Here I investigated the effect of HSP90 inhibition on the environmental buffering of wing shape and size by assessing within-individual and among-individual variations, and as a result, I found little or very weak effects on environmental and genetic buffering. The current results suggest that the role of HSP90 as a global regulator of environmental and genetic buffering is limited at least in quantitative traits.

Electrophoretic mobilities of erythrocytes in various buffers

NASA Technical Reports Server (NTRS)

Plank, L. D.; Kunze, M. E.; Todd, P. W.

1985-01-01

The calibration of space flight equipment depends on a source of standard test particles, this test particle of choice is the fixed erythrocyte. Erythrocytes from different species have different electrophoretic mobilities. Electrophoretic mobility depends upon zeta potential, which, in turn depends upon ionic strength. Zeta potential decreases with increasing ionic strength, so cells have high electrophoretic mobility in space electrophoresis buffers than in typical physiological buffers. The electrophoretic mobilities of fixed human, rat, and rabbit erythrocytes in 0.145 M salt and buffers of varying ionic strength, temperature, and composition, to assess the effects of some of the unique combinations used in space buffers were characterized. Several effects were assessed: glycerol or DMSO (dimethylsulfoxide) were considered for use as cryoprotectants. The effect of these substances on erythrocyte electrophoretic mobility was examined. The choice of buffer depended upon cell mobility. Primary experiments with kidney cells established the choice of buffer and cryoprotectant. A nonstandard temperature of EPM in the suitable buffer was determined. A loss of ionic strength control occurs in the course of preparing columns for flight, the effects of small increases in ionic strength over the expected low values need to be evaluated.

CO2 and Er:YAG laser interaction with grass tissues

NASA Astrophysics Data System (ADS)

Kim, Jaehun; Ki, Hyungson

2013-01-01

Plant leaves are multi-component optical materials consisting of water, pigments, and dry matter, among which water is the predominant constituent. In this article, we investigate laser interaction with grass using CO2 and Er:YAG lasers theoretically and experimentally, especially targeting water in grass tissues. We have first studied the optical properties of light absorbing constituents of grass theoretically, and then have identified interaction regimes and constructed interaction maps through a systematic experiment. Using the interaction maps, we have studied how interaction regimes change as process parameters are varied. This study reveals some interesting findings concerning carbonization and ablation mechanisms, the effect of laser beam diameter, and the ablation efficiency and quality of CO2 and Er:YAG lasers.

Designing hybrid grass genomes to control runoff generation

NASA Astrophysics Data System (ADS)

MacLeod, C.; Binley, A.; Humphreys, M.; King, I. P.; O'Donovan, S.; Papadopoulos, A.; Turner, L. B.; Watts, C.; Whalley, W. R.; Haygarth, P.

2010-12-01

Sustainable management of water in landscapes requires balancing demands of agricultural production whilst moderating downstream effects like flooding. Pasture comprises 69% of global agricultural areas and is essential for producing food and fibre alongside environmental goods and services. Thus there is a need to breed forage grasses that deliver multiple benefits through increased levels of productivity whilst moderating fluxes of water. Here we show that a novel grass hybrid that combines the entire genomes of perennial ryegrass (Lolium perenne - the grass of choice for Europe’s forage agriculture) and meadow fescue (Festuca pratensis) has a significant role in flood prevention. Field plot experiments established differences in runoff generation with the hybrid cultivar reducing runoff by 50% compared to perennial ryegrass cultivar, and by 35% compared to a meadow fescue cultivar (34 events over two years, replicated randomized-block design, statistically significant differences). This important research outcome was the result of a project that combined plant genetics, soil physics and plot scale hydrology to identify novel grass genotypes that can reduce runoff from grassland systems. Through a coordinated series of experiments examining effects from the gene to plot scale, we have identified that the rapid growth and then turnover of roots in the L. perenne x F. pratensis hybrid is likely to be a key mechanism in reducing runoff generation. More broadly this is an exciting first step to realizing the potential to design grass genomes to achieve both food production, and to deliver flood control, a key ecosystem service.

Suitability of multipurpose trees, shrubs and grasses to rehabilitate gullies in the sub-humid tropics

NASA Astrophysics Data System (ADS)

Talema, Ayalew; Muys, Bart; Poesen, Jean; Padro, Roc; Dibaba, Hirko; Diels, Jan

2017-04-01

Vegetation plays a vital role for sustainable rehabilitation of degraded lands. However, the selection of suitable and effective plant species remains a long-lasting challenge in most parts of the sub-humid tropics. To address this challenge 18 multipurpose plant species (6 trees, 3 shrubs and 9 grasses), preselected from the regional species pool in Southwest Ethiopia were planted in severely degraded gullies and monitored from July 2011 to June 2014. The experiment had a split-plot design with farmyard manure (FYM) application, as main plot and plant species as sub-plot factors repeated in three blocks. The study revealed that grasses were the most successful to rehabilitate the gully within the monitoring period, compared to trees and shrubs. The survival rate of the four most successful grass species, Chrysopogon zizanioides, Pennisetum macrourum, Pennisetum polystachion and Pennisetum purpureum ranged from 61 to 90% with FYM application and from 20 to 85% without FYM, while most of the well-known indigenous and exotic trees and shrubs failed to survive. For the grass Pennisetum purpureum, shoot height, shoot and root dry biomass increased by 300%, 342% and 578% respectively due to FYM application, with a remarkably higher response to FYM compared to all the other studied species. The overall results demonstrate that severely degraded lands can be effectively restored by using early successional species such as locally adapted and selected grasses before the plantation of trees and shrubs.

Subtropical grass pollen allergens are important for allergic respiratory diseases in subtropical regions

PubMed Central

2012-01-01

Background Grass pollen allergens are a major cause of allergic respiratory disease but traditionally prescribing practice for grass pollen allergen-specific immunotherapy has favoured pollen extracts of temperate grasses. Here we aim to compare allergy to subtropical and temperate grass pollens in patients with allergic rhinitis from a subtropical region of Australia. Methods Sensitization to pollen extracts of the subtropical Bahia grass (Paspalum notatum), Johnson grass (Sorghum halepense) and Bermuda grass (Cynodon dactylon) as well as the temperate Ryegrass (Lolium perenne) were measured by skin prick in 233 subjects from Brisbane. Grass pollen-specific IgE reactivity was tested by ELISA and cross-inhibition ELISA. Results Patients with grass pollen allergy from a subtropical region showed higher skin prick diameters with subtropical Bahia grass and Bermuda grass pollens than with Johnson grass and Ryegrass pollens. IgE reactivity was higher with pollen of Bahia grass than Bermuda grass, Johnson grass and Ryegrass. Patients showed asymmetric cross-inhibition of IgE reactivity with subtropical grass pollens that was not blocked by temperate grass pollen allergens indicating the presence of species-specific IgE binding sites of subtropical grass pollen allergens that are not represented in temperate grass pollens. Conclusions Subtropical grass pollens are more important allergen sources than temperate grass pollens for patients from a subtropical region. Targeting allergen-specific immunotherapy to subtropical grass pollen allergens in patients with allergic rhinitis in subtropical regions could improve treatment efficacy thereby reducing the burden of allergic rhinitis and asthma. PMID:22409901

Narrow grass hedges reduce tylosin and associated antimicrobial resistance genes in agricultural runoff

USDA-ARS?s Scientific Manuscript database

Agricultural runoff from areas receiving livestock manure can potentially contaminate surface water with antimicrobials and antimicrobial resistance genes (ARGs). The objective of this study was to investigate the effectiveness of narrow grass hedges (NGHs) on reducing the transport of antimicrobial...

Development of a sublingual allergy vaccine for grass pollinosis

PubMed Central

Frati, Franco; Scurati, Silvia; Puccinelli, Paola; David, Marie; Hilaire, Cecile; Capecce, Maurizio; Marcucci, Francesco; Incorvaia, Cristoforo

2010-01-01

Grass pollen is a very common cause of allergic rhinitis and asthma. The only treatment targeting the underlying causes of allergy is immunotherapy (IT). Sublingual immunotherapy (SLIT) has been introduced to solve the problem of systemic reactions to subcutaneous IT (SCIT). This article evaluates the characteristics of the allergen extract, Staloral, in terms of practical administration, effectiveness, safety, and mechanism of action. Efficacy data were obtained from double-blind, placebo-controlled studies using Staloral in patients sensitized to grass pollen, while practical administration, cost-effectiveness, and mechanism of action data were provided by well designed studies. The efficacy and safety of Staloral, as demonstrated by review of published studies which used doses up to 1125 times those administered with SCIT, shows that this allergen extract has optimal characteristics for treating patients with seasonal allergies due to grass pollens. The main mechanism of action is the interaction between dendritic cells of the oral mucosa and the subsequent tolerance induced in T-cells. PMID:20689696

Effects of forage types on digestibility, methane emissions, and nitrogen utilization efficiency in two genotypes of hill ewes.

PubMed

Zhao, Y G; Annett, R; Yan, T

2017-08-01

Thirty-six nonpregnant hill ewes (18 pure Scottish Blackface and 18 Swaledale × Scottish Blackface) aged 18 mo and weighing 48 ± 4.8 kg were allocated to 3 forage treatments balanced for genotype and BW. Each genotype was offered 3 forages (pelleted ryegrass, fresh lowland grass, and fresh hill grass) ad libitum with 6 ewes for each of the 6 genotype × diet combination treatments. Pelleted ryegrass was sourced from a commercial supplier (Drygrass South Western Ltd, Burrington, UK). Fresh lowland grass was harvested daily in the morning from a third regrowth perennial ryegrass () sward. Fresh hill grass was harvested from a seminatural hill grassland every 2 d and stored in plastic bags at 4 to 5°C until offered. The animals were individually housed in pens and offered experimental diets for 14 d before being transferred to 6 individual respiration chambers for a further 4 d, during which feed intake, fecal and urine outputs, and CH emissions were measured. There was no interaction between genotype and forage types on any variable measured. In a comparison of effects of the 3 forages, pelleted ryegrass had the greatest ( < 0.001) values in DMI, GE intake, CH emissions, N intake (NI), and fecal N (FN), urine N (UN), and manure N (MN) outputs, whereas hill grass had the lowest ( < 0.001) values in DMI, energy (GE, DE, and ME) intake, CH emissions, NI, UN, and MN. However, pelleted ryegrass had the lowest ratio in CH emissions per unit DMI ( = 0.022) or GE intake ( = 0.026) or UN excretion as a proportion of NI or MN ( < 0.001). Lowland grass had a greater ( < 0.001) digestibility of DM, OM, CP, NDF, ADF, and GE and a greater ( < 0.001) ME:GE ratio or retained N:NI ratio than pelleted ryegrass and hill grass. Genotypes of sheep had no effect on any variable in feed intake, digestibility, CH emissions, or N utilization. The CH conversion factors (CH energy/GE) for pelleted ryegrass, lowland grass, and hill grass were 4.4, 5.7, and 5.6%, respectively. All data were then pooled to develop regression equations between CH and DMI or between N excretions (FN, UN, and MN) and NI. Methane emissions and N excretions were positively related to DMI and NI ( < 0.001), respectively. However, increasing DMI could reduce CH emissions per kilogram DMI. These equations add new information in predicting enteric CH emissions and N utilization efficiency and can be used to quantify the environmental footprint of hill sheep production systems.

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 2. Lipids.

PubMed

Lee, M R F; Connelly, P L; Tweed, J K S; Dewhurst, R J; Merry, R J; Scollan, N D

2006-11-01

The experiment investigated the digestion of lipids from different forage silages in beef steers. Six Hereford x Friesian steers prepared with rumen and duodenal cannulas were given ad libitum access to a high-sugar grass silage, control grass silage, red clover silage, or mixtures of the red clover and each of the grass silages (50:50, DM basis). The experiment was conducted as an incomplete 5 x 5 Latin square, with an additional randomly repeated sequence. Total fatty acid and C18:3n-3 concentrations were greater (P < 0.05) for the high-sugar grass silage than the control grass silage or the red clover silage. Dry matter and total fatty acid intake were less (P < 0.05) for steers fed the control grass silage than for steers fed the other diets. Duodenal flow of C18:3n-3 was greater (P < 0.05), and flows of C18:0 and total C18:1 trans were less (P < 0.05), for the red clover silage compared with the 2 grass silage diets, with the mixtures intermediate. These results were supported by a reduction (P < 0.05) in biohydrogenation of C18:3n-3 for the red clover silage, with the mixtures again being intermediate. Flows of total branched- and odd-chain fatty acids were greater (P < 0.05) for the high-sugar grass silage diet, possibly as a result of greater microbial flow, because these fatty acids are associated with bacterial lipid. Duodenal flows of the chlorophyll metabolite, phytanic acid, were greater (P < 0.05) for animals fed the high-sugar grass silage treatments compared with the other treatments. These results confirm the potential for modifying the fatty acid composition of ruminant products by feeding red clover silage.

A molecular identification system for grasses: a novel technology for forensic botany.

PubMed

Ward, J; Peakall, R; Gilmore, S R; Robertson, J

2005-09-10

Our present inability to rapidly, accurately and cost-effectively identify trace botanical evidence remains the major impediment to the routine application of forensic botany. Grasses are amongst the most likely plant species encountered as forensic trace evidence and have the potential to provide links between crime scenes and individuals or other vital crime scene information. We are designing a molecular DNA-based identification system for grasses consisting of several PCR assays that, like a traditional morphological taxonomic key, provide criteria that progressively identify an unknown grass sample to a given taxonomic rank. In a prior study of DNA sequences across 20 phylogenetically representative grass species, we identified a series of potentially informative indels in the grass mitochondrial genome. In this study we designed and tested five PCR assays spanning these indels and assessed the feasibility of these assays to aid identification of unknown grass samples. We confirmed that for our control set of 20 samples, on which the design of the PCR assays was based, the five primer combinations produced the expected results. Using these PCR assays in a 'blind test', we were able to identify 25 unknown grass samples with some restrictions. Species belonging to genera represented in our control set were all correctly identified to genus with one exception. Similarly, genera belonging to tribes in the control set were correctly identified to the tribal level. Finally, for those samples for which neither the tribal or genus specific PCR assays were designed, we could confidently exclude these samples from belonging to certain tribes and genera. The results confirmed the utility of the PCR assays and the feasibility of developing a robust full-scale usable grass identification system for forensic purposes.

Invasion of a semi-arid shrubland by annual grasses increases autotrophic and heterotrophic soil respiration rates due to altered soil moisture and temperature patterns

NASA Astrophysics Data System (ADS)

Mauritz, M.; Hale, I.; Lipson, D.

2010-12-01

Shrub <-> grassland conversions are a globally occurring phenomenon altering habitat structure, quality and nutrient cycling. Grasses and shrubs differ in their above and belowground biomass allocation, root architecture, phenology, litter quality and quantity. Conversion affects soil microbial communities, soil moisture and temperature and carbon (C) allocation patterns. However, the effect of conversion on C storage is regionally variable and there is no consistent direction of change. In Southern California invasion by annual grasses is a major threat to native shrub communities and it has been proposed that grass invasion increases NPP and ecosystem C storage (Wolkovich et al, 2009). In order to better understand how this shrub <-> grassland conversion changes ecosystem C storage it is important to understand the partitioning of soil respiration into autotrophic and heterotrophic components. Respiration was measured in plots under shrubs and grasses from February when it was cold and wet to July when it was hot and dry, capturing seasonal transitions in temperature and water availability. Roots were excluded under shrubs and grasses with root exclusion cores to quantify heterotrophic respiration. Using total soil respiration (Rt) = autotrophic respiration (root) (Ra)+ heterotrophic respiration (microbial) (Rh) the components contributing to total soil respiration can be evaluated. Respiration, soil moisture and temperature were measured daily at four hour intervals using Licor 8100 automated chamber measurements. Throughout the measurement period, Rt under grasses exceeded Rt under shrubs. Higher Rt levels under grasses were mainly due to higher Ra in grasses rather than changes in Rh. On average grass Ra was almost double shrub Ra. Higher grass respiration levels are partially explained by differences in soil moisture and temperature between shrubs and grasses. Respiration rates responded similarly to seasonal transitions regardless of treatment although Ra had a much stronger seasonal response. Across all months changes in respiration rates are explained by changes in soil moisture. However, within wet periods respiration rates increase with temperature. From February to April the soil was wet and respiration levels gradually increased as day time soil temperatures increased. From April onwards absence of precipitation events and rising soil temperatures caused the soils to rapidly dry out. As a result Rt rates declined and gradually converged with Rh levels. As soils dried, grass Ra declined more gradually than shrub Ra. This was contrary to our expectation that shrub roots would respire longer into the dry season because they have deeper roots and can access water. The high late-season levels of respiration observed in the grass community are possibly due to the presence of invasive forbs which have deep tap roots and continue to grow after the grasses have senesced. Conversion from native shrubs to annual invasive grasses increased both Rt and Rh which indicates changes in plant C allocation and decomposition rates of soil C. The continued encroachment of grasses on shrubland has important implications for the future of C storage in this system.

Influence of herbivory and competition on invasive weed fitness: Observed effects of Cyphocleonus achates (Coleoptera: Curculionidae) and grass-seeding treatments on spotted knapweed performance

Treesearch

James S. Jacobs; Sharlene E. Sing; John M. Martin

2006-01-01

The root-feeding weevil Cyphocleonus achates (Fahraeus) is a promising biological control agent for managing the exotic, invasive weed spotted knapweed. The objective of this study was to compare the relative and potentially interactive effects of competition and specialized herbivory on spotted knapweed fitness. Competition was assessed through three grass seeding...

Effects of prescribed burning and litter type on litter decomposition and nutrient release in mixed-grass prairie in Eastern Montana

USDA-ARS?s Scientific Manuscript database

Fire can affect litter decomposition and carbon (C) and nitrogen (N) dynamics. Here, we examined the effect of summer fire and three litter types on litter decomposition and litter C and N dynamics in a northern mixed-grass prairie over a 24 month period starting ca. 14 months after fire. Over all...

Presence of Trifolium repens Promotes Complementarity of Water Use and N Facilitation in Diverse Grass Mixtures.

PubMed

Hernandez, Pauline; Picon-Cochard, Catherine

2016-01-01

Legume species promote productivity and increase the digestibility of herbage in grasslands. Considerable experimental data also indicate that communities with legumes produce more above-ground biomass than is expected from monocultures. While it has been attributed to N facilitation, evidence to identify the mechanisms involved is still lacking and the role of complementarity in soil water acquisition by vertical root differentiation remains unclear. We used a 20-months mesocosm experiment to investigate the effects of species richness (single species, two- and five-species mixtures) and functional diversity (presence of the legume Trifolium repens) on a set of traits related to light, N and water use and measured at community level. We found a positive effect of Trifolium presence and abundance on biomass production and complementarity effects in the two-species mixtures from the second year. In addition the community traits related to water and N acquisition and use (leaf area, N, water-use efficiency, and deep root growth) were higher in the presence of Trifolium. With a multiple regression approach, we showed that the traits related to water acquisition and use were with N the main determinants of biomass production and complementarity effects in diverse mixtures. At shallow soil layers, lower root mass of Trifolium and higher soil moisture should increase soil water availability for the associated grass species. Conversely at deep soil layer, higher root growth and lower soil moisture mirror soil resource use increase of mixtures. Altogether, these results highlight N facilitation but almost soil vertical differentiation and thus complementarity for water acquisition and use in mixtures with Trifolium. Contrary to grass-Trifolium mixtures, no significant over-yielding was measured for grass mixtures even those having complementary traits (short and shallow vs. tall and deep). Thus, vertical complementarity for soil resources uptake in mixtures was not only dependant on the inherent root system architecture but also on root plasticity. We also observed a time-dependence for positive complementarity effects due to the slow development of Trifolium in mixtures, possibly induced by competition with grasses. Overall, our data underlined that soil water resource was an important driver of over-yielding and complementarity effects in Trifolium-grass mixtures.

META-ANALYSIS OF NITROGEN REMOVAL IN RIPARIAN BUFFERS

EPA Science Inventory

Riparian buffer zones, the vegetated region adjacent to streams and wetlands, are thought to be effective at intercepting and controlling nitrogen loads entering water bodies. Riparian buffer width may be positively related to nitrogen removal effectiveness by influencing nitrog...

High effective cytosolic H+ buffering in mouse cortical astrocytes attributable to fast bicarbonate transport.

PubMed

Theparambil, Shefeeq M; Deitmer, Joachim W

2015-09-01

Cytosolic H(+) buffering plays a major role for shaping intracellular H(+) shifts and hence for the availability of H(+) for biochemical reactions and acid/base-coupled transport processes. H(+) buffering is one of the prime means to protect the cell from large acid/base shifts. We have used the H(+) indicator dye BCECF and confocal microscopy to monitor the cytosolic H(+) concentration, [H(+)]i, in cultured cortical astrocytes of wild-type mice and of mice deficient in sodium/bicarbonate cotransporter NBCe1 (NBCe1-KO) or in carbonic anhydrase isoform II (CAII-KO). The steady-state buffer strength was calculated from the amplitude of [H(+)]i transients as evoked by CO2/HCO3(-) and by butyric acid in the presence and absence of CO2/HCO3(-). We tested the hypotheses if, in addition to instantaneous physicochemical H(+) buffering, rapid acid/base transport across the cell membrane contributes to the total, "effective" cytosolic H(+) buffering. In the presence of 5% CO2/26 mM HCO3(-), H(+) buffer strength in astrocytes was increased 4-6 fold, as compared with that in non-bicarbonate, HEPES-buffered solution, which was largely attributable to fast HCO3 (-) transport into the cells via NBCe1, supported by CAII activity. Our results show that within the time frame of determining physiological H(+) buffering in cells, fast transport and equilibration of CO2/H(+)/HCO3(-) can make a major contribution to the total "effective" H(+) buffer strength. Thus, "effective" cellular H(+) buffering is, to a large extent, attributable to membrane transport of base equivalents rather than a purely passive physicochemical process, and can be much larger than reported so far. Not only physicochemical H(+) buffering, but also rapid import of HCO3(-) via the electrogenic sodium-bicarbonate cotransporter NBCe1, supported by carbonic anhydrase II (CA II), was identified to enhance cytosolic H(+) buffer strength substantially. © 2015 Wiley Periodicals, Inc.

Semi Automated Ferrous Material Scouring System (SAFMSS)

DTIC Science & Technology

2016-03-14

represent real world conditions with various shrubs or grasses entangled with the debris preventing easy removal. Our second tests were performed at...would expect on a range. Soil types, compaction, shrubs , grasses and roots as well as ferrous content vs item weight all have an effect on actual

Suppression of cheatgrass by established perennial grasses: I. mechanisms

USDA-ARS?s Scientific Manuscript database

Cheatgrass is often considered a competitive species. In a greenhouse experiment using rhizotrons, we tested the effect of established perennial grasses (Indian ricegrass, creeping wildrye, and Snake River wheatgrass) on the growth of cheatgrass. The soil was a sandy loam A horizon of a Xeric Haploc...

Associations between grass and weed pollen and emergency department visits for asthma among children in Montreal.

PubMed

Héguy, Léa; Garneau, Michelle; Goldberg, Mark S; Raphoz, Marie; Guay, Frédéric; Valois, Marie-France

2008-02-01

Asthma among children is a major public health problem worldwide. There are increasing number of studies suggesting a possible association between allergenic pollen and exacerbations of asthma. In the context of global climate change, a number of future climate and air pollution scenarios predict increases in concentrations of pollen, an extension of the pollen season, and an increase in the allergenicity of pollen. The goal of the present study is to evaluate the short-term effects of exposure to grass and weed pollen on emergency department visits and readmissions for asthma among children aged 0-9 years living in Montreal between April and October, 1994-2004. Time-series analyses were carried out using parametric log-linear overdispersed Poisson models that were adjusted for temporal variations, daily weather conditions (temperature, atmospheric pressure), and gaseous air pollutants (ozone and nitrogen dioxide). We have found positive associations between emergency department visits and concentrations of grass pollen 3 days after exposure. The effect of grass pollen was higher on emergency department readmissions as compared to initial visits. Weak negative associations were found between weed pollen (including ragweed pollen) and emergency department visits 2 days after exposure. The data indicate that among children, emergency department visits increased with increasing concentrations of grass pollen.

Photo-protective mechanisms in reed canary grass to alleviate photo-inhibition of PSII on the Qinghai-Tibet Plateau.

PubMed

Zhang, Chao; Zhang, Da-Wei; Sun, Yan-Ni; Arfan, Muhammad; Li, Da-Xu; Yan, Jia-Jun; You, Ming-Hong; Bai, Shi-Qie; Lin, Hong-Hui

2017-08-01

Due to its characteristic of high biomass yield potential, there is considerable interest in cultivating Phalaris arundinacea L. cv. 'chuancaoyin No.3' (reed canary grass) on the Qinghai-Tibet Plateau where there is an abundance of alpine steppe meadow and a potential large market for animal husbandry. In this study, we 1) investigate whether reed canary grass exhibits superior productive capacity to Elymus nutans 'Aba' (E. nutans), ordinary common pasture, during the long warm days of summer at high-altitude; and 2) compare the cold tolerance between reed canary grass and E. nutans, including photosynthesis, photo-inhibition, and photo-protection. The results suggest that reed canary grass exhibits higher photosynthetic capacity compared to E. nutans at latitudes of the cool temperate zone. Meanwhile, cold-induced photo-inhibition and photo-damage at high altitudes in reed canary grass were due to both stomatal and non-stomatal limitation, and the enhancement in photo-respiration, thermal dissipation, and Mehler reaction are important processes to minimize the negative effects of high elevation and a cold environment. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Invasion of non-native grasses causes a drop in soil carbon storage in California grasslands

NASA Astrophysics Data System (ADS)

Koteen, Laura E.; Baldocchi, Dennis D.; Harte, John

2011-10-01

Vegetation change can affect the magnitude and direction of global climate change via its effect on carbon cycling among plants, the soil and the atmosphere. The invasion of non-native plants is a major cause of land cover change, of biodiversity loss, and of other changes in ecosystem structure and function. In California, annual grasses from Mediterranean Europe have nearly displaced native perennial grasses across the coastal hillsides and terraces of the state. Our study examines the impact of this invasion on carbon cycling and storage at two sites in northern coastal California. The results suggest that annual grass invasion has caused an average drop in soil carbon storage of 40 Mg/ha in the top half meter of soil, although additional mechanisms may also contribute to soil carbon losses. We attribute the reduction in soil carbon storage to low rates of net primary production in non-native annuals relative to perennial grasses, a shift in rooting depth and water use to primarily shallow sources, and soil respiratory losses in non-native grass soils that exceed production rates. These results indicate that even seemingly subtle land cover changes can significantly impact ecosystem functions in general, and carbon storage in particular.

Coyote (Canis latrans) mammalian prey diet shifts in response to seasonal vegetation change.

PubMed

Seamster, Virginia A; Waits, Lisette P; Macko, Stephen A; Shugart, Herman H

2014-01-01

Drylands typically have strong seasonal variation in rainfall and primary productivity. This study examines the effects of seasonal change in grass-derived resource availability on the base of the food chain of a mammalian predator. Seasonal changes in live grass cover were measured in two vegetation types at the Sevilleta National Wildlife Refuge in central New Mexico, USA. Non-invasive genetic sampling of scat was used to identify individuals in the local coyote (Canis latrans) population. Stable carbon and nitrogen isotope analysis of hair removed from scats of 45 different coyotes was used to assess seasonal variation in the diet of mammalian coyote prey that came from C4 grasses. Live grass cover increased from the spring to the summer and fall; contribution of C4 grasses to the diet of mammalian coyote prey increased from the summer to the fall and was higher in grassland areas. There were significant differences in the seasonal patterns in the prey diet between grassland and shrubland areas.

Study of variability in antioxidant composition and fatty acids profile of Longissimus dorsi and Serratus ventralis muscles from Iberian pigs reared in two different Montanera seasons.

PubMed

Tejerina, D; García-Torres, S; de Vaca, M Cabeza; Vázquez, F M; Cava, R

2012-02-01

This investigation was designed to evaluate the effects of variations in antioxidant and fatty acids composition of acorns and grass from two Montanera (free-range system and feeding based on acorns and grass) seasons (2006/07 and 2007/08) on the antioxidant composition and fatty acids profile of m. Longissimus dorsi (LD) and m. Serratus ventralis (SV) from Iberian pigs reared under these Montanera seasons. Acorn and grass composition was affected by Montanera season and consequently, LD and SV muscles showed different contents of α-tocopherol, total phenols, hydrophilic and lipophilic antioxidant activity and fatty acid profile, according with the composition of acorns and grass ingested. Results suggest a lack of uniformity in meat quality between different seasons. This could be due to the variable nature of extensive pig production as reflected in the variability in the composition of the diet (acorns and grass). Copyright © 2011 Elsevier Ltd. All rights reserved.

Direct Solvothermal Liquefaction of Pennisetum purpureum Biomass to Produce Biocrude Using Ethanol Solvent

NASA Astrophysics Data System (ADS)

Adriane Ochiai, Mikael; Marrod Cruz, Salvador; Oporto, Louiellyn; de Leon, Rizalinda

2018-03-01

Direct solvothermal liquefaction was used in converting the lignocellulosic biomass, Pennisetum purpureum or Napier grass using ethanol as solvent. Liquefaction of Napier grass resulted in a dark and viscous bio-crude product and exhibited promising yields (34.6377% to 48.6267%). It was determined that the effects of temperature and residence time were statistically significant with the residence time having the greatest positive effect on yield. High yields of bio-crude from Napier grass seem to occur when solvothermal temperature, residence time increased and as solids ratio decreased. However, elemental analysis showed that the bio-crude produced needs to undergo deoxygenation (O: 14.25 - 49.42%) before mixing with petroleum. For the higher heating value (HHV), the parameters observed in the study were statistically insignificant, however, temperature was determined to have the greatest positive effect on HHV. It was observed that high HHV bio-crude were produced at high temperatures, low solids ratio, and low residence times. The acquired averages for the HHV (20.0333 MJ/kg to 29.7744 MJ/kg) were all higher than the HHV of the Napier grass sample used in the study (12.9394 MJ/kg). It was observed in the study, that even though solids ratio has the least effect on both responses, the choice of solids ratio is dependent on its interaction effects with the other parameters as its effects contribute to the observed responses.

Silage preparation and fermentation quality of natural grasses treated with lactic acid bacteria and cellulase in meadow steppe and typical steppe

PubMed Central

Hou, Meiling; Gentu, Ge; Liu, Tingyu; Jia, Yushan; Cai, Yimin

2017-01-01

Objective In order to improve fermentation quality of natural grasses, their silage preparation and fermentation quality in meadow steppe (MS) and typical steppe (TS) were studied. Methods The small-scale silages and round bale silages of mixed natural grasses in both steppes were prepared using the commercial lactic acid bacteria (LAB) inoculants Chikuso-1 (CH, Lactobacillus plantarum) and cellulase enzyme (AC, Acremonium cellulase) as additives. Results MS and TS contained 33 and 9 species of natural grasses, respectively. Stipa baicalensis in MS and Stipa grandi in TS were the dominant grasses with the highest dry matter (DM) yield. The crude protein (CP), neutral detergent fiber and water-soluble carbohydrate of the mixed natural grasses in both steppes were 8.02% to 9.03%, 66.75% to 69.47%, and 2.02% to 2.20% on a DM basis, respectively. All silages treated with LAB and cellulase were well preserved with lower pH, butyric acid and ammonia-N content, and higher lactic acid and CP content than those of control in four kinds of silages. Compared with CH- or AC-treated silages, the CH+ AC-treated silages had higher lactic acid content. Conclusion The results confirmed that combination with LAB and cellulase may result in beneficial effects by improving the natural grass silage fermentation in both grasslands. PMID:27703133

EnviroAtlas -- Fresno, California -- One Meter Resolution Urban Land Cover Data (2010)

EPA Pesticide Factsheets

The Fresno, CA EnviroAtlas One-Meter-scale Urban Land Cover Data were generated via supervised classification of combined aerial photography and LiDAR data. The air photos were United States Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP) four band (red, green, blue, and near infrared) aerial photography at 1-m spatial resolution. Aerial photography ('imagery') was collected on multiple dates in summer 2010. Seven land cover classes were mapped: Water, impervious surfaces (Impervious), soil and barren (Soil), trees and forest (Tree), and grass and herbaceous non-woody vegetation (Grass), agriculture (Ag), and Orchards. An accuracy assessment of 500 completely random and 103 stratified random points yielded an overall User's fuzzy accuracy of 81.1 percent (see below). The area mapped is defined by the US Census Bureau's 2010 Urban Statistical Area for Fresno, CA plus a 1-km buffer. Where imagery was available, additional areas outside the 1-km boundary were also mapped but not included in the accuracy assessment. We expect the accuracy of the areas outside of the 1-km boundary to be consistent with those within. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The da

EnviroAtlas -- Fresno, California -- One Meter Resolution Urban Land Cover Data (2010) Web Service

EPA Pesticide Factsheets

This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). The Fresno, CA EnviroAtlas One-Meter-scale Urban Land Cover Data were generated via supervised classification of combined aerial photography and LiDAR data. The air photos were United States Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP) four band (red, green, blue, and near infrared) aerial photography at 1-m spatial resolution. Aerial photography ('imagery') was collected on multiple dates in summer 2010. Seven land cover classes were mapped: Water, impervious surfaces (Impervious), soil and barren (Soil), trees and forest (Tree), and grass and herbaceous non-woody vegetation (Grass), agriculture (Ag), and Orchards. An accuracy assessment of 500 completely random and 103 stratified random points yielded an overall User's fuzzy accuracy of 81.1 percent (see below). The area mapped is defined by the US Census Bureau's 2010 Urban Statistical Area for Fresno, CA plus a 1-km buffer. Where imagery was available, additional areas outside the 1-km boundary were also mapped but not included in the accuracy assessment. We expect the accuracy of the areas outside of the 1-km boundary to be consistent with those within. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with

Nutritive Value Response of Native Warm-Season Forage Grasses to Harvest Intervals and Durations in Mixed Stands

PubMed Central

Temu, Vitalis W.; Rude, Brian J.; Baldwin, Brian S.

2014-01-01

Interest in management of native warm-season grasses for multiple uses is growing in southeastern USA. Forage quality response of early-succession mixed stands of big bluestem (BB, Andropogon gerardii), indiangrass (IG, Sorghastrum nutans), and little bluestem (SG, Schizachyrium scoparium) to harvest intervals (30-, 40-, 60-, 90 or 120-d) and durations (one or two years) were assessed in crop-field buffers. Over three years, phased harvestings were initiated in May, on sets of randomized plots, ≥90 cm apart, in five replications (blocks) to produce one-, two-, and three-year-old stands, by the third year. Whole-plot regrowths were machine-harvested after collecting species (IG and LB) sample tillers for leafiness estimates. Species-specific leaf area (SLA) and leaf-to-stem ratio (LSR) were greater for early-season harvests and shorter intervals. In a similar pattern, whole-plot crude protein concentrations were greatest for the 30-d (74 g·kg−1 DM) and the least (40 g·kg−1 DM) for the 120-d interval. Corresponding neutral detergent fiber (NDF) values were the lowest (620 g·kg−1 DM) and highest (710 g·kg−1 DM), respectively. In vitro dry matter and NDF digestibility were greater for early-season harvests at shorter intervals (63 and 720 g·kg−1 DM). With strategic harvesting, similar stands may produce quality hay for beef cattle weight gain. PMID:27135504

A VSA-based strategy for placing conservation buffers in agricultural watersheds.

PubMed

Qiu, Zeyuan

2003-09-01

Conservation buffers have the potential to reduce agricultural nonpoint source pollution and improve terrestrial wildlife habitat, landscape biodiversity, flood control, recreation, and aesthetics. Conservation buffers, streamside areas and riparian wetlands are being used or have been proposed to control agricultural nonpoint source pollution. This paper proposes an innovative strategy for placing conservation buffers based on the able source area (VSA) hydrology. VSAs are small, variable but predictable portion of a watershed that regularly contributes to runoff generation. The VSA-based strategy involves the following three steps: first, identifying VSAs in landscapes based on natural characteristics such as hydrology, land use/cover, topography and soils; second, targeting areas within VSAs for conservation buffers; third, refining the size and location of conservation buffers based on other factors such as weather, environmental objectives, available funding and other best management practices. Building conservation buffers in VSAs allows agricultural runoff to more uniformly enter buffers and stay there longer, which increases the buffer's capacity to remove sediments and nutrients. A field-scale example is presented to demonstrate the effectiveness and cost-effectiveness of the within-VSA conservation buffer scenario relative to a typical edge-of-field buffer scenario. The results enhance the understanding of hydrological processes and interactions between agricultural lands and conservation buffers in agricultural landscapes, and provide practical guidance for land resource managers and conservationists who use conservation buffers to improve water quality and amenity values of agricultural landscape.

Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells.

PubMed

Nam, Joo-Youn; Kim, Hyun-Woo; Lim, Kyeong-Ho; Shin, Hang-Sik; Logan, Bruce E

2010-01-15

Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pK(a) of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities. Copyright 2009 Elsevier B.V. All rights reserved.

Effects of hypertonic buffer composition on lymph node uptake and bioavailability of rituximab, after subcutaneous administration.

PubMed

Fathallah, Anas M; Turner, Michael R; Mager, Donald E; Balu-Iyer, Sathy V

2015-03-01

The subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after s.c. administration remains a major challenge. In this work we investigated the effects of excipient dependent hyperosmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as the animal model, we compared the effects of NaCl, mannitol and O-phospho-L-serine (OPLS) on the plasma concentration of rituximab over 5 days after s.c. administration. An increase was observed in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, compared with isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to the improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph nodes in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatics, as estimated by the model, increased from 0.05% in isotonic buffer to 13% in hypertonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. The data suggest that hypertonic solutions may be a viable option for improving s.c. bioavailability. Copyright © 2014 John Wiley & Sons, Ltd.

Effects of hypertonic buffer composition on lymph node uptake and bioavailability of rituximab, after subcutaneous administration

PubMed Central

Fathallah, Anas M.; Turner, Michael R.; Balu-Iyer, Sathy V.

2015-01-01

Subcutaneous administration of biologics is highly desirable; however, incomplete bioavailability after sc administration remains a major challenge. In this work we investigated the effects of excipient dependent hyper-osmolarity on lymphatic uptake and plasma exposure of rituximab as a model protein. Using Swiss Webster (SW) mice as our animal model, we compared the effects of NaCl, mannitol and, O-Phospho-L-Serine (OPLS) on plasma concentration of rituximab over 5 days after sc administration. We observed an increase in plasma concentrations in animals administered rituximab in hypertonic buffer solutions, as compared to isotonic buffer. Bioavailability, as estimated by our pharmacokinetic model, increased from 29% in isotonic buffer to 54% in hypertonic buffer containing NaCl, to almost complete bioavailability in hypertonic buffers containing high dose OPLS or mannitol. This improvement in plasma exposure is due to improved lymphatic trafficking as evident from the increase in the fraction of dose trafficked through the lymph node in the presence of hypertonic buffers. The fraction of the dose trafficked through the lymphatic, as estimated by the model, increased from 0.05 % in isotonic buffer to 13% in hyper-tonic buffer containing NaCl to about 30% for hypertonic buffers containing high dose OPLS and mannitol. Our data suggests that hypertonic solutions may be a viable option to improve sc bioavailability. PMID:25377184

Grass mulching effect on infiltration, surface runoff and soil loss of three agricultural soils in Nigeria.

PubMed

Adekalu, K O; Olorunfemi, I A; Osunbitan, J A

2007-03-01

Mulching the soil surface with a layer of plant residue is an effective method of conserving water and soil because it reduces surface runoff, increases infiltration of water into the soil and retard soil erosion. The effectiveness of using elephant grass (Pennisetum purpureum) as mulching material was evaluated in the laboratory using a rainfall simulator set at rainfall intensities typical of the tropics. Six soil samples, two from each of the three major soil series representing the main agricultural soils in South Western Nigeria were collected, placed on three different slopes, and mulched with different rates of the grass. The surface runoff, soil loss, and apparent cumulative infiltration were then measured under each condition. The results with elephant grass compared favorably with results from previous experiments using rice straw. Runoff and soil loss decreased with the amount of mulch used and increased with slope. Surface runoff, infiltration and soil loss had high correlations (R = 0.90, 0.89, and 0.86, respectively) with slope and mulch cover using surface response analysis. The mean surface runoff was correlated negatively with sand content, while mean soil loss was correlated positively with colloidal content (clay and organic matter) of the soil. Infiltration was increased and soil loss was reduced greatly with the highest cover. Mulching the soils with elephant grass residue may benefit late cropping (second cropping) by increasing stored soil water for use during dry weather and help to reduce erosion on sloping land.

EnviroAtlas - Austin, TX - Riparian Buffer Land Cover by Block Group

EPA Pesticide Factsheets

This EnviroAtlas dataset describes the percentage of forested, vegetated, and impervious land within 15- and 50-meters of hydrologically connected streams, rivers, and other water bodies within the EnviroAtlas community area. Forest is defined as Trees & Forest. Vegetated cover is defined as Trees & Forest and Grass & Herbaceous. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

The Influence of Ca2+ Buffers on Free [Ca2+] Fluctuations and the Effective Volume of Ca2+ Microdomains

PubMed Central

Weinberg, Seth H.; Smith, Gregory D.

2014-01-01

Intracellular calcium (Ca2+) plays a significant role in many cell signaling pathways, some of which are localized to spatially restricted microdomains. Ca2+ binding proteins (Ca2+ buffers) play an important role in regulating Ca2+ concentration ([Ca2+]). Buffers typically slow [Ca2+] temporal dynamics and increase the effective volume of Ca2+ domains. Because fluctuations in [Ca2+] decrease in proportion to the square-root of a domain’s physical volume, one might conjecture that buffers decrease [Ca2+] fluctuations and, consequently, mitigate the significance of small domain volume concerning Ca2+ signaling. We test this hypothesis through mathematical and computational analysis of idealized buffer-containing domains and their stochastic dynamics during free Ca2+ influx with passive exchange of both Ca2+ and buffer with bulk concentrations. We derive Langevin equations for the fluctuating dynamics of Ca2+ and buffer and use these stochastic differential equations to determine the magnitude of [Ca2+] fluctuations for different buffer parameters (e.g., dissociation constant and concentration). In marked contrast to expectations based on a naive application of the principle of effective volume as employed in deterministic models of Ca2+ signaling, we find that mobile and rapid buffers typically increase the magnitude of domain [Ca2+] fluctuations during periods of Ca2+ influx, whereas stationary (immobile) Ca2+ buffers do not. Also contrary to expectations, we find that in the absence of Ca2+ influx, buffers influence the temporal characteristics, but not the magnitude, of [Ca2+] fluctuations. We derive an analytical formula describing the influence of rapid Ca2+ buffers on [Ca2+] fluctuations and, importantly, identify the stochastic analog of (deterministic) effective domain volume. Our results demonstrate that Ca2+ buffers alter the dynamics of [Ca2+] fluctuations in a nonintuitive manner. The finding that Ca2+ buffers do not suppress intrinsic domain [Ca2+] fluctuations raises the intriguing question of whether or not [Ca2+] fluctuations are a physiologically significant aspect of local Ca2+ signaling. PMID:24940787

The influence of Ca²⁺ buffers on free [Ca²⁺] fluctuations and the effective volume of Ca²⁺ microdomains.

PubMed

Weinberg, Seth H; Smith, Gregory D

2014-06-17

Intracellular calcium (Ca(2+)) plays a significant role in many cell signaling pathways, some of which are localized to spatially restricted microdomains. Ca(2+) binding proteins (Ca(2+) buffers) play an important role in regulating Ca(2+) concentration ([Ca(2+)]). Buffers typically slow [Ca(2+)] temporal dynamics and increase the effective volume of Ca(2+) domains. Because fluctuations in [Ca(2+)] decrease in proportion to the square-root of a domain's physical volume, one might conjecture that buffers decrease [Ca(2+)] fluctuations and, consequently, mitigate the significance of small domain volume concerning Ca(2+) signaling. We test this hypothesis through mathematical and computational analysis of idealized buffer-containing domains and their stochastic dynamics during free Ca(2+) influx with passive exchange of both Ca(2+) and buffer with bulk concentrations. We derive Langevin equations for the fluctuating dynamics of Ca(2+) and buffer and use these stochastic differential equations to determine the magnitude of [Ca(2+)] fluctuations for different buffer parameters (e.g., dissociation constant and concentration). In marked contrast to expectations based on a naive application of the principle of effective volume as employed in deterministic models of Ca(2+) signaling, we find that mobile and rapid buffers typically increase the magnitude of domain [Ca(2+)] fluctuations during periods of Ca(2+) influx, whereas stationary (immobile) Ca(2+) buffers do not. Also contrary to expectations, we find that in the absence of Ca(2+) influx, buffers influence the temporal characteristics, but not the magnitude, of [Ca(2+)] fluctuations. We derive an analytical formula describing the influence of rapid Ca(2+) buffers on [Ca(2+)] fluctuations and, importantly, identify the stochastic analog of (deterministic) effective domain volume. Our results demonstrate that Ca(2+) buffers alter the dynamics of [Ca(2+)] fluctuations in a nonintuitive manner. The finding that Ca(2+) buffers do not suppress intrinsic domain [Ca(2+)] fluctuations raises the intriguing question of whether or not [Ca(2+)] fluctuations are a physiologically significant aspect of local Ca(2+) signaling. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Monitoring Liverworts to Evaluate the Effectiveness of Hydroriparian Buffers

NASA Astrophysics Data System (ADS)

Higgins, Kellina L.; Yasué, Maï

2014-01-01

In the coastal temperate rainforest of British Columbia (BC) in western Canada, government policies stipulate that foresters leave unlogged hydroriparian buffer strips up to 25 m on each side of streams to protect wildlife habitat. At present, studies on the effectiveness of these buffers focus on mammals, birds, and amphibians while there is comparably little information on smaller organisms such as liverworts in these hydroriparian buffers. To address this gap of knowledge, we conducted field surveys of liverworts comparing the percent cover and community composition in hydroriparian forested areas ( n = 4 sites, n = 32 plots with nested design) to hydroriparian buffer zones ( n = 4 sites, n = 32 plots). We also examined how substrate type affected the cover of liverworts. Liverwort communities in buffers were similar to those in riparian forest areas and most liverworts were found on downed wood. Thus, hydroriparian buffers of 25-35 m on each side in a coastal temperate rainforest effectively provide habitat for liverworts as long as downed wood is left intact in the landscape. Because liverworts are particularly sensitive to changes in humidity, these results may indicate that hydroriparian buffers are an effective management strategy for bryophytes and possibly for a range of other riparian species that are particularly sensitive to forestry-related changes in microclimate.

Impacts of leguminous shrub encroachment on neighboring grasses include transfer of fixed nitrogen.

PubMed

Zhang, Hai-Yang; Yu, Qiang; Lü, Xiao-Tao; Trumbore, Susan E; Yang, Jun-Jie; Han, Xing-Guo

2016-04-01

Shrub encroachment induced by global change and human disturbance strongly affects ecosystem structure and function. In this study, we explore the degree to which invading leguminous shrubs affected neighboring grasses, including via the transfer of fixed nitrogen (N). We measured N concentrations and natural abundance (15)N of shoot tissues from three dominant grasses from different plant functional groups across seven distances along a local transect (up to 500 cm) to the leguminous shrub, Caragana microphylla. C. microphylla did transfer fixed N to neighboring grasses, but the amount and distance of N transferred were strongly species-specific. Shoot N concentrations decreased significantly with distance from C. microphylla, for a rhizomatous grass, Leymus chinensis, and a bunchgrass, Achnatherum sibiricum. However, N concentrations of another bunchgrass, Stipa grandis, were higher only directly underneath the shrub canopy. Shoot δ(15)N values of L. chinensis were enriched up to 500 cm from the shrub, but for S. grandis were enriched only below the shrub canopy. In contrast, δ(15)N of A. sibiricum did not change along the 500-cm transect. Our results indicated the rhizomatous grass transferred fixed N over long distances while bunchgrasses did not. The presence of C. microphylla increased the shoot biomass of L. chinensis but decreased that of S. grandis and A. sibiricum. These findings highlight the potential role of nutrient-acquisition strategies of neighboring grasses in moderating the interspecific variation of fixed N transfer from the leguminous shrub. Overall, leguminous shrubs have either positive or negative effects on the neighboring grasses and dramatically affect plant community composition and structure.

Methane production by anaerobic digestion of Bermuda grass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klass, D.L.; Ghosh, S.

1981-01-01

Bermuda grass (Cynodon dactylon) is one of the high-yield warm-season grasses that has been suggested as a promising raw material for conversion to methane. Experimental work performed with laboratory digesters to study the anaerobic digestion of Coastal Bermuda grass harvested in Louisiana and having a C/N ratio of 24 is described. Methane yields of about 1.9 SCF/lb of volatile solids (VS) added were observed under conventional mesophilic high-rate conditions. When supplemental nitrogen additions were made, the methane yields increased. This observation along with the compositional data compiled on the grass used in this work indicated that the nitrogen content ofmore » the unsupplemented grass was insufficient to sustain high-rate digestion at the higher yield level. However, as the C/N ratio was reduced by addition of ammonium chloride, the methane yield continually increased up to 3.5 SCF/lb added at the lowest C/N ratio examined (6.3) even after relatively high concentrations of ammonium nitrogen were measured in the effluent. It appears that the added nutrient had a stimulatory effect on methane production above the point where nitrogen was not limiting. Thermophilic digestion with supplemental nitrogen additions afforded methane yields of about 2.7 SCF/lb VS added. Carbon and energy balances were calculated and the relative biodegradabilities of the organics were estimated. It was concluded from this work that Coastal Bermuda grass can be converted to high-methane gas under conventional anaerobic digestion conditions. The performance of the particular lot of grass studied was substantially improved by supplemental nitrogen additions. (Refs. 12).« less

Competition effects from cheatgrass (Bromus tectorum) differs among perennial grasses of the Great Basin

USDA-ARS?s Scientific Manuscript database

Competition from the exotic annual grass, cheatgrass (Bromus tectorum), threatens millions of hectares of native plant communities throughout the Great Basin. The Nature Conservancy has identified the Great Basin as the third most endangered ecosystem in the United States. Not only has increased fue...

Life cycle expression analysis of three cell wall degradation-related genes in ethylene-treated grass

USDA-ARS?s Scientific Manuscript database

Ethylene regulates multiple developmental processes during a plant life cycle, but the effect of ethylene on the upregulation of senescence-, stress-, and post-harvest-related genes in forage grasses is poorly understood. In this work, we used quantitative PCR to determine whether ethylene applicat...

The effect of ensiling and haymaking on the concentrations of steroidal saponin in two Brachiaria grass species

USDA-ARS?s Scientific Manuscript database

Brachiaria (signalgrass) is now the most widely used tropical grass genus in Central and South America. However, Brachiaria spp. can cause hepatogenous photosensitization in livestock. Steroidal saponins, specifically protodioscin, present in Brachiaria spp. may be responsible for liver injury and s...

Plant-soil feedbacks and the reversal of desertification with climate change

USDA-ARS?s Scientific Manuscript database

Our objective was to provide a conceptual framework for perennial grass recovery in a series of wet years, which includes both plant-soil feedbacks that increase available water to grasses and effects of precipitation on a sequence of recovery-related processes. We tested hypotheses based on this fr...

Effects of grass silage quality and level of feed intake on enteric methane production in lactating dairy cows.

PubMed

Warner, D; Bannink, A; Hatew, B; van Laar, H; Dijkstra, J

2017-08-01

The objective of this study was to determine the effect of level of feed intake and quality of ryegrass silage as well as their interaction on enteric methane (CH) emission from dairy cows. In a randomized block design, 56 lactating dairy cows received a diet of grass silage, corn silage, and a compound feed meal (70:10:20 on DM basis). Treatments consisted of 4 grass silage qualities prepared from grass harvested from leafy through late heading stage, and offered to dairy cows at 96 ± 2.4 (mean ± SEM) days in milk (namely, high intake) and 217 ± 2.4 d in milk (namely, low intake). Grass silage CP content varied between 124 and 286 g/kg of DM, and NDF content between 365 and 546 g/kg of DM. After 12 d of adaptation, enteric CH production of cows was measured in open-circuit climate-controlled respiration chambers for 5 d. No interaction between DMI and grass quality on CH emission, or on milk production, diet digestibility, and energy, and N retention was found ( ≥ 0.17). Cows had a greater DMI (16.6 vs. 15.5 kg/d; SEM 0.46) and greater fat- and protein-corrected milk (FPCM) yield (29.9 vs. 25.4 kg/d; SEM 1.24) at high than low intake (both ≤ 0.001). Apparent total-tract nutrient digestibility was not affected ( ≥ 0.08) by DMI level. Total enteric CH production (346 ± 10.9 g/d) was not affected ( = 0.15) by DMI level. A small, significant ( = 0.025) decrease at high compared with low intake occurred for CH yield (21.8 ± 0.59 g/kg of DMI; -4%). Methane emission intensity (12.8 ± 0.56 g/kg of FPCM; -12%) was considerably smaller ( ≤ 0.001) at high intake as a result of greater milk yields realized in early lactation. As grass quality decreased from leafy through late heading stage, FPCM yield and apparent total-tract OM digestibility declined (-12%; ≤ 0.015), whereas total CH production (+13%), CH yield (+21%), and CH emission intensity (+28%) increased ( ≤ 0.001). Our results suggest that improving grass silage quality by cutting grass at an earlier stage considerably reduces enteric CH emissions from dairy cows, independent of DMI. In contrast, losses of N in manure increased for the earlier cut grass silage treatments. The small increase in DMI at high intake was associated with a small to moderate reduction in CH emission per unit of DMI and GE intake. This study confirmed that enteric CH emissions from dairy cows at distinct levels of feed intake depend on the nutritive value and chemical composition of the grass silage.

Social Support for Divorced Fathers' Parenting: Testing a Stress-Buffering Model*

PubMed Central

DeGarmo, David S.; Patras, Joshua; Eap, Sopagna

2008-01-01

A stress-buffering hypothesis for parenting was tested in a county-representative sample of 218 divorced fathers. Social support for parenting (emergency and nonemergency child care, practical support, financial support) was hypothesized to moderate effects of stress (role overload, coparental conflict, and daily hassles) on fathers’ quality parenting. No custody fathers relied more on relatives compared with custodial fathers, who relied more on new partners for parenting support. No differences by custody status were found on levels of support or parenting over time. Parenting support buffered effects of change in role overload and coparenting conflict on coercive parenting and buffered effects of change in daily hassles on prosocial parenting. Buffer effects were more predictive over time. Implications for practice and preventive intervention strategies are discussed. PMID:19177181

Globes from global data: Charting international research networks with the GRASS GIS r.out.polycones add-on module.

NASA Astrophysics Data System (ADS)

Löwe, Peter

2015-04-01

Many Free and Open Source Software (FOSS) tools have been created for the various application fields within geoscience. While FOSS allows re-implementation of functionalities in new environments by access to the original codebase, the easiest approach to build new software solutions for new problems is the combination or merging of existing software tools. Such mash-ups are implemented by embedding and encapsulating FOSS tools within each another, effectively focusing the use of the embedded software to the specific role it needs to perform in the given scenario, while ignoring all its other capabilities. GRASS GIS is a powerful and established FOSS GIS for raster, vector and volume data processing while the Generic Mapping Tools (GMT) are a suite of powerful Open Source mapping tools, which exceed the mapping capabilities of GRASS GIS. This poster reports on the new GRASS GIS add-on module r.out.polycones. It enables users to utilize non-continuous projections for map production within the GRASS production environment. This is implemented on the software level by encapsulating a subset of GMT mapping capabilities into a GRASS GIS (Version 6.x) add-on module. The module was developed at the German National Library of Science and Technology (TIB) to provide custom global maps of scientific collaboration networks, such as the DataCite consortium, the registration agency for Digital Object Identifiers (DOI) for research data. The GRASS GIS add-on module can be used for global mapping of raster data into a variety of non continuous sinosoidal projections, allowing the creation of printable biangles (gores) to be used for globe making. Due to the well structured modular nature of GRASS modules, technical follow-up work will focus on API-level Python-based integration in GRASS 7 [1]. Based on this, GMT based mapping capabilities in GRASS will be extended beyond non-continuous sinosoidal maps and advanced from raster-layers to content GRASS display monitors. References: [1] Petras, V., Petrasova, A., Chemin, Y., Zambelli, P., Landa, M., Gebbert, S., Neteler, N., Löwe, P.: Analyzing rasters, vectors and time series using new Python interfaces in GRASS GIS 7, Geophysical Research Abstracts Vol. 17, EGU2015-8142, 2015 (in preparation)

A genome-wide meta-analysis of genetic variants associated with allergic rhinitis and grass sensitization and their interaction with birth order.

PubMed

Ramasamy, Adaikalavan; Curjuric, Ivan; Coin, Lachlan J; Kumar, Ashish; McArdle, Wendy L; Imboden, Medea; Leynaert, Benedicte; Kogevinas, Manolis; Schmid-Grendelmeier, Peter; Pekkanen, Juha; Wjst, Matthias; Bircher, Andreas J; Sovio, Ulla; Rochat, Thierry; Hartikainen, Anna-Liisa; Balding, David J; Jarvelin, Marjo-Riitta; Probst-Hensch, Nicole; Strachan, David P; Jarvis, Deborah L

2011-11-01

Hay fever or seasonal allergic rhinitis (AR) is a chronic disorder associated with IgE sensitization to grass. The underlying genetic variants have not been studied comprehensively. There is overwhelming evidence that those who have older siblings have less AR, although the mechanism for this remains unclear. We sought to identify common genetic variant associations with prevalent AR and grass sensitization using existing genome-wide association study (GWAS) data and to determine whether genetic variants modify the protective effect of older siblings. Approximately 2.2 million genotyped or imputed single nucleotide polymorphisms were investigated in 4 large European adult cohorts for AR (3,933 self-reported cases vs 8,965 control subjects) and grass sensitization (2,315 cases vs 10,032 control subjects). Three loci reached genome-wide significance for either phenotype. The HLA variant rs7775228, which cis-regulates HLA-DRB4, was strongly associated with grass sensitization and weakly with AR (P(grass) = 1.6 × 10(-9); P(AR) = 8.0 × 10(-3)). Variants in a locus near chromosome 11 open reading frame 30 (C11orf30) and leucine-rich repeat containing 32 (LRRC32), which was previously associated with atopic dermatitis and eczema, were also strongly associated with both phenotypes (rs2155219; P(grass) = 9.4 × 10(-9); P(AR) = 3.8 × 10(-8)). The third genome-wide significant variant was rs17513503 (P(grass) = 1.2 × 10(-8); PAR = 7.4 × 10(-7)) which was located near transmembrane protein 232 (TMEM232) and solute carrier family 25, member 46 (SLC25A46). Twelve further loci with suggestive associations were also identified. Using a candidate gene approach, where we considered variants within 164 genes previously thought to be important, we found variants in 3 further genes that may be of interest: thymic stromal lymphopoietin (TSLP), Toll-like receptor 6 (TLR6) and nucleotide-binding oligomerization domain containing 1 (NOD1/CARD4). We found no evidence for variants that modified the effect of birth order on either phenotype. This relatively large meta-analysis of GWASs identified few loci associated with AR and grass sensitization. No birth order interaction was identified in the current analyses. Copyright © 2011 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Effect of Chemicals on the Cell Membrane Transport of Nucleosides.

DTIC Science & Technology

1983-08-01

hypoxanthine in the external buffer and the efflux mte is decreased by uric acid in tne buffer. Perfluorodecanoic acid ( PFDA ), adenine, or xanthlne...uric acid in the buffer. Perfluorodecanoic acid ( PFDA ), Sadenine, or xanthine in the external buffer have no direct effect on the rate of AP efflux, in...observed that perfluorooctanoic acid ( PFOA ) produces a transient weight N loss, but no mortality in young rats. By contrast, the treatment of rats with

Buffer layer dependence of magnetoresistance effects in Co2Fe0.4Mn0.6Si/MgO/Co50Fe50 tunnel junctions

NASA Astrophysics Data System (ADS)

Sun, Mingling; Kubota, Takahide; Takahashi, Shigeki; Kawato, Yoshiaki; Sonobe, Yoshiaki; Takanashi, Koki

2018-05-01

Buffer layer dependence of tunnel magnetoresistance (TMR) effects was investigated in Co2Fe0.4Mn0.6Si (CFMS)/MgO/Co50Fe50 magnetic tunnel junctions (MTJs). Pd, Ru and Cr were selected for the buffer layer materials, and MTJs with three different CFMS thicknesses (30, 5, and 0.8 nm) were fabricated. A maximum TMR ratio of 136% was observed in the Ru buffer layer sample with a 30-nm-thick CFMS layer. TMR ratios drastically degraded for the CFMS thickness of 0.8 nm, and the values were 26% for Cr buffer layer and less than 1% for Pd and Ru buffer layers. From the annealing temperature dependence of the TMR ratios, amounts of interdiffusion and effects from the lattice mismatch were discussed.

Uptake of 2,4,6-Trinitrotoluene (TNT) by Vetiver grass (Vetiviera ziznoides L.) -- Preliminary results from a hydroponic study

NASA Astrophysics Data System (ADS)

Shakya, K. M.; Sarkar, D.; Datta, R.; Makris, K.; Pachanoor, D.

2006-05-01

2,4,6-Trinitrotoluene(TNT) is a potent mutagen and a Group C human carcinogen that has been widely used to produce munitions and explosives. As a result, vast areas that have been previously used as military ranges, munition burning and open detonation sites have been heavily contaminated with TNT. Conventional remedial activities in such contaminated sites commonly rely on methods such as incineration, land filling and soil composting. Phytoremediation offers a cost-effective solution, utilizing plants to phytoextract TNT from the contaminated soil. We propose the use of vetiver grass (Vetiveria zizanoides) to remove TNT from such contaminated soils. Vetiver is a fast-growing and adaptive grass, enabling its use in TNT-contaminated sites in a wide variety of soil types and climate. We also hypothesized that TNT removal by vetiver grass will be enhanced by utilizing a chaotropic agent (urea) to alter rhizosphere/root hair chemical environment. The objectives of this preliminary hydroponic study were: i) to investigate the effectiveness of vetiver grass in removing TNT from solution, and ii) to evaluate the use of a common agrochemical (urea) in enhancing TNT removal by vetiver grass. Vetiver plants were grown in a hydroponic system with five different TNT concentrations (0, 5, 10, 25, and 50 mg TNT L-1) and three urea concentrations (0, 0.01 and 0.1%). A plant density of 10 g L-1 and three replicate vessels per treatment were used. Aliquots were collected at several time intervals up to 192 hour, and were analyzed for TNT with HPLC. Results showed that vetiver was able to remove TNT from hydroponic solutions. The overall magnitude and kinetics of TNT removal by vetiver grass was enhanced in the presence of urea. TNT removal kinetics depended on TNT and urea initial concentrations, suggestive of second-order kinetic reactions. Preliminary results are encouraging, but in need for verification using more detailed studies involving TNT-contaminated soils. Ongoing research in our lab attempts to elucidate TNT fate and stability upon uptake by vetiver grass using plant extraction methods and enzyme activity assays.

Reprogrammable read only variable threshold transistor memory with isolated addressing buffer

DOEpatents

Lodi, Robert J.

1976-01-01

A monolithic integrated circuit, fully decoded memory comprises a rectangular array of variable threshold field effect transistors organized into a plurality of multi-bit words. Binary address inputs to the memory are decoded by a field effect transistor decoder into a plurality of word selection lines each of which activates an address buffer circuit. Each address buffer circuit, in turn, drives a word line of the memory array. In accordance with the word line selected by the decoder the activated buffer circuit directs reading or writing voltages to the transistors comprising the memory words. All of the buffer circuits additionally are connected to a common terminal for clearing all of the memory transistors to a predetermined state by the application to the common terminal of a large magnitude voltage of a predetermined polarity. The address decoder, the buffer and the memory array, as well as control and input/output control and buffer field effect transistor circuits, are fabricated on a common substrate with means provided to isolate the substrate of the address buffer transistors from the remainder of the substrate so that the bulk clearing function of simultaneously placing all of the memory transistors into a predetermined state can be performed.

Modeling of the Modulation by Buffers of Ca2+ Release through Clusters of IP3 Receptors

PubMed Central

Zeller, S.; Rüdiger, S.; Engel, H.; Sneyd, J.; Warnecke, G.; Parker, I.; Falcke, M.

2009-01-01

Abstract Intracellular Ca2+ release is a versatile second messenger system. It is modeled here by reaction-diffusion equations for the free Ca2+ and Ca2+ buffers, with spatially discrete clusters of stochastic IP3 receptor channels (IP3Rs) controlling the release of Ca2+ from the endoplasmic reticulum. IP3Rs are activated by a small rise of the cytosolic Ca2+ concentration and inhibited by large concentrations. Buffering of cytosolic Ca2+ shapes global Ca2+ transients. Here we use a model to investigate the effect of buffers with slow and fast reaction rates on single release spikes. We find that, depending on their diffusion coefficient, fast buffers can either decouple clusters or delay inhibition. Slow buffers have little effect on Ca2+ release, but affect the time course of the signals from the fluorescent Ca2+ indicator mainly by competing for Ca2+. At low [IP3], fast buffers suppress fluorescence signals, slow buffers increase the contrast between bulk signals and signals at open clusters, and large concentrations of buffers, either fast or slow, decouple clusters. PMID:19686646

Field effect transistors improve buffer amplifier

NASA Technical Reports Server (NTRS)

1967-01-01

Unity gain buffer amplifier with a Field Effect Transistor /FET/ differential input stage responds much faster than bipolar transistors when operated at low current levels. The circuit uses a dual FET in a unity gain buffer amplifier having extremely high input impedance, low bias current requirements, and wide bandwidth.

Grass pollen allergens globally: the contribution of subtropical grasses to burden of allergic respiratory diseases.

PubMed

Davies, J M

2014-06-01

Grass pollens of the temperate (Pooideae) subfamily and subtropical subfamilies of grasses are major aeroallergen sources worldwide. The subtropical Chloridoideae (e.g. Cynodon dactylon; Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass) species are abundant in parts of Africa, India, Asia, Australia and the Americas, where a large and increasing proportion of the world's population abide. These grasses are phylogenetically and ecologically distinct from temperate grasses. With the advent of global warming, it is conceivable that the geographic distribution of subtropical grasses and the contribution of their pollen to the burden of allergic rhinitis and asthma will increase. This review aims to provide a comprehensive synthesis of the current global knowledge of (i) regional variation in allergic sensitivity to subtropical grass pollens, (ii) molecular allergenic components of subtropical grass pollens and (iii) allergic responses to subtropical grass pollen allergens in relevant populations. Patients from subtropical regions of the world show higher allergic sensitivity to grass pollens of Chloridoideae and Panicoideae grasses, than to temperate grass pollens. The group 1 allergens are amongst the allergen components of subtropical grass pollens, but the group 5 allergens, by which temperate grass pollen extracts are standardized for allergen content, appear to be absent from both subfamilies of subtropical grasses. Whilst there are shared allergenic components and antigenic determinants, there are additional clinically relevant subfamily-specific differences, at T- and B-cell levels, between pollen allergens of subtropical and temperate grasses. Differential immune recognition of subtropical grass pollens is likely to impact upon the efficacy of allergen immunotherapy of patients who are primarily sensitized to subtropical grass pollens. The literature reviewed herein highlights the clinical need to standardize allergen preparations for both types of subtropical grass pollens to achieve optimal diagnosis and treatment of patients with allergic respiratory disease in subtropical regions of the world. © 2014 John Wiley & Sons Ltd.

50 CFR 21.49 - Control order for resident Canada geese at airports and military airfields.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., (F) Registered animal drugs, pesticides, and repellants, (G) Cervical dislocation, and (H) CO2..., fleshy owl's clover, Colusa grass, hairy Orcutt grass, Solano grass, Greene's tuctoria, Sacramento Valley Orcutt grass, San Joaquin Valley Orcutt grass, slender Orcutt grass, California Orcutt grass, spreading...

50 CFR 21.49 - Control order for resident Canada geese at airports and military airfields.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., (F) Registered animal drugs, pesticides, and repellants, (G) Cervical dislocation, and (H) CO2..., fleshy owl's clover, Colusa grass, hairy Orcutt grass, Solano grass, Greene's tuctoria, Sacramento Valley Orcutt grass, San Joaquin Valley Orcutt grass, slender Orcutt grass, California Orcutt grass, spreading...

50 CFR 21.50 - Depredation order for resident Canada geese nests and eggs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... goldfields, Hoover's spurge, fleshy owl's clover, Colusa grass, hairy Orcutt grass, Solano grass, Greene's tuctoria, Sacramento Valley Orcutt grass, San Joaquin Valley Orcutt grass, slender Orcutt grass, California Orcutt grass, spreading navarretia, and San Jacinto Valley crownscale. (e) Can the depredation order be...

50 CFR 21.50 - Depredation order for resident Canada geese nests and eggs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... goldfields, Hoover's spurge, fleshy owl's clover, Colusa grass, hairy Orcutt grass, Solano grass, Greene's tuctoria, Sacramento Valley Orcutt grass, San Joaquin Valley Orcutt grass, slender Orcutt grass, California Orcutt grass, spreading navarretia, and San Jacinto Valley crownscale. (e) Can the depredation order be...

Small mammal use of native warm-season and non-native cool-season grass forage fields

USGS Publications Warehouse

Ryan L Klimstra,; Christopher E Moorman,; Converse, Sarah J.; Royle, J. Andrew; Craig A Harper,

2015-01-01

Recent emphasis has been put on establishing native warm-season grasses for forage production because it is thought native warm-season grasses provide higher quality wildlife habitat than do non-native cool-season grasses. However, it is not clear whether native warm-season grass fields provide better resources for small mammals than currently are available in non-native cool-season grass forage production fields. We developed a hierarchical spatially explicit capture-recapture model to compare abundance of hispid cotton rats (Sigmodon hispidus), white-footed mice (Peromyscus leucopus), and house mice (Mus musculus) among 4 hayed non-native cool-season grass fields, 4 hayed native warm-season grass fields, and 4 native warm-season grass-forb ("wildlife") fields managed for wildlife during 2 summer trapping periods in 2009 and 2010 of the western piedmont of North Carolina, USA. Cotton rat abundance estimates were greater in wildlife fields than in native warm-season grass and non-native cool-season grass fields and greater in native warm-season grass fields than in non-native cool-season grass fields. Abundances of white-footed mouse and house mouse populations were lower in wildlife fields than in native warm-season grass and non-native cool-season grass fields, but the abundances were not different between the native warm-season grass and non-native cool-season grass fields. Lack of cover following haying in non-native cool-season grass and native warm-season grass fields likely was the key factor limiting small mammal abundance, especially cotton rats, in forage fields. Retention of vegetation structure in managed forage production systems, either by alternately resting cool-season and warm-season grass forage fields or by leaving unharvested field borders, should provide refugia for small mammals during haying events.

Occupational endotoxin exposure in association with atopic sensitization and respiratory health in adults: Results of a 5-year follow-up.

PubMed

Spierenburg, Elisabeth A J; Smit, Lidwien A M; Krop, Esmeralda J M; Heederik, Dick; Hylkema, Machteld N; Wouters, Inge M

2017-01-01

The objective of the present longitudinal study was to investigate the effects of occupational endotoxin exposure on respiratory health and atopic sensitization in adults. Health outcomes and personal endotoxin exposure estimates were determined for 234 farmers and agricultural workers both at baseline and 5 years later. A questionnaire was used to assess respiratory symptoms, spirometry tests were performed and total and specific IgE levels were measured in serum. A twofold increase in personal endotoxin exposure was associated with less hay fever (OR 0.68, 95%CI 0.54-0.87) and grass IgE positivity (OR 0.81, 95%CI 0.68-0.97) at both time points ("persistent" versus "never"). Although not statistically significant, a consistent protective pattern was observed for an increased loss of hay fever symptoms (OR 2.19, 95%CI 0.96-4.99) and grass IgE positivity (OR 1.24, 95%CI 0.76-2.02), and for less new-onset of hay fever (OR 0.87, 95%CI 0.65-1.17), grass IgE positivity (OR 0.83, 95%CI 0.61-1.12) and atopic sensitization (OR 0.75, 95%CI 0.55-1.02). Endotoxin exposure was not associated with changes in lung function. We showed that occupational endotoxin exposure is associated with a long-term protective effect on hay fever and grass IgE positivity. Results on longitudinal changes in hay fever, atopy and grass IgE positivity in adulthood were consistent with a protective effect of endotoxin exposure, but results need to be confirmed in larger cohorts. An effect of endotoxin exposure on lung function decline was not found.

Interaction between C 4 barnyard grass and C 3 upland rice under elevated CO 2: Impact of mycorrhizae

NASA Astrophysics Data System (ADS)

Tang, Jianjun; Xu, Liming; Chen, Xin; Hu, Shuijin

2009-03-01

Atmospheric CO 2 enrichment may impact arbuscular mycorrhizae (AM) development and function, which could have subsequent effects on host plant species interactions by differentially affecting plant nutrient acquisition. However, direct evidence illustrating this scenario is limited. We examined how elevated CO 2 affects plant growth and whether mycorrhizae mediate interactions between C 4 barnyard grass ( Echinochloa crusgalli (L.) Beauv.) and C 3 upland rice ( Oryza sativa L.) in a low nutrient soil. The monocultures and combinations with or without mycorrhizal inoculation were grown at ambient (400 ± 20 μmol mol -1) and elevated CO 2 (700 ± 20 μmol mol -1) levels. The 15N isotope tracer was introduced to quantify the mycorrhizally mediated N acquisition of plants. Elevated CO 2 stimulated the growth of C 3 upland rice but not that of C 4 barnyard grass under monoculture. Elevated CO 2 also increased mycorrhizal colonization of C 4 barnyard grass but did not affect mycorrhizal colonization of C 3 upland rice. Mycorrhizal inoculation increased the shoot biomass ratio of C 4 barnyard grass to C 3 upland rice under both CO 2 concentrations but had a greater impact under the elevated than ambient CO 2 level. Mycorrhizae decreased relative interaction index (RII) of C 3 plants under both ambient and elevated CO 2, but mycorrhizae increased RII of C 4 plants only under elevated CO 2. Elevated CO 2 and mycorrhizal inoculation enhanced 15N and total N and P uptake of C 4 barnyard grass in mixture but had no effects on N and P acquisition of C 3 upland rice, thus altering the distribution of N and P between the species in mixture. These results implied that CO 2 stimulation of mycorrhizae and their nutrient acquisition may impact competitive interaction of C 4 barnyard grass and C 3 upland rice under future CO 2 scenarios.

Atmospheric optical depth effects on angular anisotropy of plant canopy reflectance

NASA Technical Reports Server (NTRS)

Deering, Donald W.; Eck, Thomas F.

1987-01-01

The effects of varying atmospheric aerosol optical depth on the bidirectional reflectance distribution of vegetation canopies is investigated. The reflectance distributions of two pasture grass canopies and one soya bean canopy under different sky irradiance distributions were measured, and the data were analyzed in the visible and IR spectral bands. It is observed that, for the pasture grass canopies, the change in reflectance is due to the percentage of shadowed area viewed by the sensor, and for the soya bean, the specular reflection effect and increased diffuse irradiance penetration into the canopy cause reflectance changes. It is detected that the reflectivity for the soya bean canopy on a hazy day is lower than on a clear day; however, the opposite change is observed for the pasture grass. It is also detected that the normalized difference vegetation index values differ under clear and hazy conditions for the same vegetation canopy conditions.

Common garden comparisons of reproductive, forage and weed suppression potential of rangeland rehabilitation grasses of the Great Basin

USDA-ARS?s Scientific Manuscript database

Common garden experiments are a means to remove environmental effects. Using 8 species of perennial rangeland grasses, we established a common garden (3 reps x28 plants = 84 plants/species). We found that ‘Hycrest’ crested wheatgrass (Agropyron cristatum) and bluebunch wheatgrass (Pseudoroegneria sp...

75 FR 46924 - Notice of Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-04

... high and adverse human health impacts or environmental effects from exposure to the pesticides... regulator, trinexapac-ethyl: 4-(cyclopropyl-[alpha]-hydroxy-methylene)- 3,5-dioxo-cyclohexanecarboxylic acid...,5-dioxo-cyclohexanecarboxylic acid, in or on grass, forage, grown for seed at 1.60 ppm; grass, hay...

Genetic Dissection of Seed Production Traits and Identification of a Major-Effect Seed Retention QTL in Hybrid Leymus (Triticeae) Wildryes

USDA-ARS?s Scientific Manuscript database

Many native grasses display seed shattering and other seed production problems. Basin wildrye (Leymus cinereus) and creeping wildrye (L. triticoides) are perennial Triticeae grasses native to western North America. In this study, variation in the number of florets per inflorescence, percent seed s...

Drought effects on composition and yield for corn stover, mixed grasses, and Miscanthus as bioenergy feedstocks

USDA-ARS?s Scientific Manuscript database

Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study was to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed perennial grasses from Conservation Reserve Program de...

Consumption of endophyte-infected fescue seed during the dry period does not decrease milk production in the following lactation

USDA-ARS?s Scientific Manuscript database

Ergot alkaloids in endophyte-infected grasses inhibit prolactin (PRL) secretion and may reduce milk production of cows consuming endophyte-infected grasses. We investigated the effects of consuming endophyte-infected fescue during late lactation and the dry period on mammary growth, differentiation ...

The effect of rodent seed predation on four species of California annual grasses.

PubMed

Borchert, M I; Jain, S K

1978-01-01

The effect of seed predation by Microtus californicus and Mus musculus on plant numbers of four species of California annual grasses was investigated for one year period on a grassland near Davis, California. In winter, mice utilized dead star thistle plants for cover when grasses in open areas were short, but moved into open areas when grass grew tall in spring.Using exclosures and plots sown with known quantities of seed, it was estimated that a mouse population (approximate density 120/acre) consumed 75% of Avena fatua seed, 44% of Hordeum leporinum seed, and 37% of Bromus diandrus seed. Mice showed a strong preference for Avena seed.Plant numbers of Avena and Hordeum were reduced by 62% and 30%, respectively. Hordeum, Lolium, and to a lesser extent, Bromus responded to a competitive release from Avena by increases in plant size and reproductive output. In addition, seed predation markedly increased seed to adult plant survivorship of Avena, Hordeum, and Bromus.Vertebrate seed predation is discussed as a potentially important factor in the yearly patterns of plant population regulation in California annual grasslands.

High-pressure carbon dioxide/water pre-treatment of sugarcane bagasse and elephant grass: Assessment of the effect of biomass composition on process efficiency.

PubMed

Toscan, Andréia; Morais, Ana Rita C; Paixão, Susana M; Alves, Luís; Andreaus, Jürgen; Camassola, Marli; Dillon, Aldo José Pinheiro; Lukasik, Rafal M

2017-01-01

The performance of two lignocellulosic biomasses was studied in high-pressure carbon dioxide/water pre-treatment. Sugarcane bagasse and elephant grass were used to produce C 5 -sugars from hemicellulose and, simultaneously, to promote cellulose digestibility for enzymatic saccharification. Different pre-treatment conditions, with combined severity factor ranging from -1.17 to -0.04, were evaluated and maximal total xylan to xylose yields of 59.2wt.% (34.4wt.% xylooligomers) and 46.4wt.% (34.9wt.% xylooligomers) were attained for sugarcane bagasse and elephant grass, respectively. Furthermore, pre-treated biomasses were highly digestible, with glucan to glucose yields of 77.2mol% and 72.4mol% for sugarcane bagasse and elephant grass, respectively. High-pressure carbon dioxide/water pre-treatment provides high total C 5 -sugars and glucose recovery from both lignocellulosic biomasses; however it is highly influenced by composition and intrinsic features of each biomass. The obtained results confirm this approach as an effective and greener alternative to conventional pre-treatment processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of fatigue and environment on residual strengths of center-cracked graphite/epoxy buffer strip panels

NASA Technical Reports Server (NTRS)

Bigelow, Catherine A.

1989-01-01

The effects of fatigue, moisture conditioning, and heating on the residual tension strengths of center-cracked graphite/epoxy buffer strip panels were evaluated using specimens made with T300/5208 graphite epoxy in a 16-ply quasi-isotropic layup, with two different buffer strip materials, Kevlar-49 or S-glass. It was found that, for panels subjected to fatigue loading, the residual strengths were not significantly affected by the fatigue loading, the number of repetitions of the loading spectrum, or the maximum strain level. The moisture conditioning reduced the residual strengths of the S-glass buffer strip panels by 10 to 15 percent below the ambient results, but increased the residual strengths of the Kevlar-49 buffer strip panels slightly. For both buffer strip materials, the heat increased the residual strengths of the buffer strip panels slightly over the ambient results.

Buffer salt effects in off-line coupling of capillary electrophoresis and mass spectrometry.

PubMed

Marák, Jozef; Stanová, Andrea

2014-05-01

In this work, the impact of buffer salts/matrix effects on the signal in direct injection MS with an electrospray interface (DI-ESI-MS) following pITP fractionation of the sample was studied. A range of buffers frequently used in CE analyses (pH 3-10) was prepared containing 10, 50, and 90% v/v of ACN, respectively. The sets of calibration solutions of cetirizine (an antihistaminic drug with an amphiprotic character) within a 0.05-2.0 mg/L concentration range were prepared in different buffers. The greatest enhancements in the MS signal (in terms of change in the slope of the calibration line) were obtained for the beta-alanine buffer (pH 3.5) in positive ionization and for the borate buffer (pH 9.2) in negative ionization, respectively. The procedure was successfully applied to the analysis of buserelin (a peptidic drug). The slope of the calibration line for solutions containing the beta-alanine buffer with 50% of ACN was 4 times higher than for water or urine, respectively. This study clearly demonstrates that the buffer salt/matrix effects in an offline combination of pITP and DI-ESI-MS can also play a positive role, as they can enhance the signal in MS. A similar influence of the above effects can also be presumed in the CE techniques combined on-line with ESI-MS.

Modified band alignment effect in ZnO/Cu2O heterojunction solar cells via Cs2O buffer insertion

NASA Astrophysics Data System (ADS)

Eom, Kiryung; Lee, Dongyoon; Kim, Seunghwan; Seo, Hyungtak

2018-02-01

The effects of a complex buffer layer of cesium oxide (Cs2O) on the photocurrent response in oxide heterojunction solar cells (HSCs) were investigated. A p-n junction oxide HSC was fabricated using p-type copper (I) oxide (Cu2O) and n-type zinc oxide (ZnO); the buffer layer was inserted between the Cu2O and fluorine-doped tin oxide (FTO). Ultraviolet-visible (UV-vis) and x-ray and ultraviolet photoelectron spectroscopy analyses were performed to characterize the electronic band structures of cells, both with and without this buffer layer. In conjunction with the measured band electronic structures, the significantly improved visible-range photocurrent spectra of the buffer-inserted HSC were analyzed in-depth. As a result, the 1 sun power conversion efficiency was increased by about three times by the insertion of buffer layer. The physicochemical origin of the photocurrent enhancement was mainly ascribed to the increased photocarrier density in the buffer layer and modified valence band offset to promote the effective hole transfer at the interface to FTO on the band-alignment model.

Effect of buffer at nanoscale molecular recognition interfaces - electrostatic binding of biological polyanions.

PubMed

Rodrigo, Ana C; Laurini, Erik; Vieira, Vânia M P; Pricl, Sabrina; Smith, David K

2017-10-19

We investigate the impact of an over-looked component on molecular recognition in water-buffer. The binding of a cationic dye to biological polyanion heparin is shown by isothermal calorimetry to depend on buffer (Tris-HCl > HEPES > PBS). The heparin binding of self-assembled multivalent (SAMul) cationic micelles is even more buffer dependent. Multivalent electrostatic molecular recognition is buffer dependent as a result of competitive interactions between the cationic binding interface and anions present in the buffer.

Divergent evapotranspiration partition dynamics between shrubs and grasses in a shrub-encroached steppe ecosystem.

PubMed

Wang, Pei; Li, Xiao-Yan; Wang, Lixin; Wu, Xiuchen; Hu, Xia; Fan, Ying; Tong, Yaqin

2018-06-04

Previous evapotranspiration (ET) partitioning studies have usually neglected competitions and interactions between antagonistic plant functional types. This study investigated whether shrubs and grasses have divergent ET partition dynamics impacted by different water-use patterns, canopy structures, and physiological properties in a shrub-encroached steppe ecosystem in Inner Mongolia, China. The soil water-use patterns of shrubs and grasses have been quantified by an isotopic tracing approach and coupled into an improved multisource energy balance model to partition ET fluxes into soil evaporation, grass transpiration, and shrub transpiration. The mean fractional contributions to total ET were 24 ± 13%, 20 ± 4%, and 56 ± 16% for shrub transpiration, grass transpiration, and soil evaporation respectively during the growing season. Difference in ecohydrological connectivity and leaf development both contributed to divergent transpiration partitioning between shrubs and grasses. Shrub-encroachment processes result in larger changes in the ET components than in total ET flux, which could be well explained by changes in canopy resistance, an ecosystem function dominated by the interaction of soil water-use patterns and ecosystem structure. The analyses presented here highlight the crucial effects of vegetation structural changes on the processes of land-atmosphere interaction and climate feedback. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Intake and digestion of wethers fed with dwarf elephant grass hay with or without the inclusion of peanut hay.

PubMed

Schnaider, Maria Alice; Ribeiro-Filho, Henrique Mendonça Nunes; Vilmar Kozloski, Gilberto; Reiter, Tatiana; Dall Orsoletta, Aline Cristina; Dallabrida, Ademar Luiz

2014-08-01

The aim of this study was to evaluate the effect of the inclusion of peanut (Arachis pintoi cv. Amarillo) hay in diets based on dwarf elephant grass (DEG, Pennisetum purpureum Schum cv. Kurumi) hay of different regrowth ages on forage intake and digestibility in wether lambs. The experimental treatments consisted of DEG hay with an interval of regrowth of 30 or 45 days offered as the only feed or in mixture with peanut hay (300 g/kg of total dry matter (DM)), which were tested in eight Texel × Suffolk crossbred wethers in a replicated 4 × 4 Latin square experiment. Both organic matter (OM) and digestible OM intakes were higher (P < 0.05) in animals receiving the legume forage. Total apparent OM digestibility was higher (P < 0.05) at an increased grass regrowth age. Ruminal OM digestibility increased (P < 0.05) with legume inclusion and at a higher grass regrowth age. The nitrogen (N) intake was higher (P < 0.05) in legume treatments and lower (P < 0.05) as the grass regrowth age increased, but retention of N was not affected by treatments. Duodenal flow of both, non-ammonia N and microbial N, were not affected by legume inclusion and were lower (P < 0.05) as grass regrowth age increased. The efficiency of rumen microbial protein synthesis (ERMPS) was negatively affected (P < 0.05) by legume inclusion and was lower (P < 0.05) as the grass regrowth age increased. Supplementation of dwarf elephant grass hay cut at the vegetative stage with peanut legume hay improves nutritional supply to wethers due to an increase in the forage intake.

Plant assemblage composition and soil P concentration differentially affect communities of AM and total fungi in a semi-arid grassland.

PubMed

Klabi, Rim; Bell, Terrence H; Hamel, Chantal; Iwaasa, Alan; Schellenberg, Mike; Raies, Aly; St-Arnaud, Marc

2015-01-01

Adding inorganic P- and N-fixing legumes to semi-arid grasslands can increase forage yield, but soil nutrient concentrations and plant cover may also interact to modify soil fungal populations, impacting short- and long-term forage production. We tested the effect of plant assemblage (seven native grasses, seven native grasses + the domesticated N-fixing legume Medicago sativa, seven native grasses + the native N-fixing legume Dalea purpurea or the introduced grass Bromus biebersteinii + M. sativa) and soil P concentration (addition of 0 or 200 P2O5 kg ha(-1) at sowing) on the diversity and community structure of arbuscular mycorrhizal (AM) fungi and total fungi over two consecutive years, using 454-pyrosequencing of 18S rDNA and ITS amplicons. Treatment effects were stronger in the wet year (2008) than the dry year (2009). The presence of an N-fixing legume with native grasses generally increased AM fungal diversity, while the interaction between soil P concentration and plant assemblage modified total fungal community structure in 2008. Excluding interannual variations, which are likely driven by moisture and plant productivity, AM fungal communities in semi-arid grasslands appear to be primarily affected by plant assemblage composition, while the composition of other fungi is more closely linked to soil P. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of the heterogeneous landscape on a predator-prey system

NASA Astrophysics Data System (ADS)

Lee, Sang-Hee

2010-01-01

In order to understand how a heterogeneous landscape affects a predator-prey system, a spatially explicit lattice model consisting of predators, prey, grass, and landscape was constructed. The predators and preys randomly move on the lattice space and the grass grows in its neighboring site according to its growth probability. When predators and preys meet at the same site at the same time, a number of prey, equal to the number of predators are eaten. This rule was also applied to the relationship between the prey and grass. The predator (prey) could give birth to an offspring when it ate prey (grass), with a birth probability. When a predator or prey animal was initially introduced, or newly born, its health state was set at a given high value. This health state decreased by one with every time step. When the state of an animal decreased to less than zero, the animal died and was removed from the system. The heterogeneous landscape was characterized by parameter H, which controlled the heterogeneity according to the neutral model. The simulation results showed that H positively or negatively affected a predator’s survival, while its effect on prey and grass was less pronounced. The results can be understood by the disturbance of the balance between the prey and predator densities in the areas where the animals aggregated.

C4 grasses prosper as carbon dioxide eliminates desiccation in warmed semi-arid grassland.

PubMed

Morgan, Jack A; LeCain, Daniel R; Pendall, Elise; Blumenthal, Dana M; Kimball, Bruce A; Carrillo, Yolima; Williams, David G; Heisler-White, Jana; Dijkstra, Feike A; West, Mark

2011-08-03

Global warming is predicted to induce desiccation in many world regions through increases in evaporative demand. Rising CO(2) may counter that trend by improving plant water-use efficiency. However, it is not clear how important this CO(2)-enhanced water use efficiency might be in offsetting warming-induced desiccation because higher CO(2) also leads to higher plant biomass, and therefore greater transpirational surface. Furthermore, although warming is predicted to favour warm-season, C(4) grasses, rising CO(2) should favour C(3), or cool-season plants. Here we show in a semi-arid grassland that elevated CO(2) can completely reverse the desiccating effects of moderate warming. Although enrichment of air to 600 p.p.m.v. CO(2) increased soil water content (SWC), 1.5/3.0 °C day/night warming resulted in desiccation, such that combined CO(2) enrichment and warming had no effect on SWC relative to control plots. As predicted, elevated CO(2) favoured C(3) grasses and enhanced stand productivity, whereas warming favoured C(4) grasses. Combined warming and CO(2) enrichment stimulated above-ground growth of C(4) grasses in 2 of 3 years when soil moisture most limited plant productivity. The results indicate that in a warmer, CO(2)-enriched world, both SWC and productivity in semi-arid grasslands may be higher than previously expected.

Evaluation of Feed for Thin-Tailed Sheep Fattening with Supplemented Protected and Unprotected Aldehide

NASA Astrophysics Data System (ADS)

Riyanto, J.; Sudibya

2018-02-01

The purpose of this study was to determine the effect of the use of soybean protection supplements in sheep ration in vivo in terms of consumption, digestibility, nutrient value index, and the digestible nutrients in the ration. Livestock used in this study were 15 heads of thintailed sheep male with an average body weight of 20.81 ± 1.40kg. The rations used in this study consisted of elephant grass, basal concentrate, soybean groats protected and without protected. The comparison between elephant grass and basalt concentrate is 30:70. Feed treatment in the form of supplementary concentrate from soybean groats ingredients without protection and protection. Protection of soybeans using 37% formaldehyde. The treatment given is P0 = 30% Elephant grass + 70% Basal concentrate, P1 = 30% Elephant grass + 60% Basal Concentrate + 10% soybeans groats without formaldehyde protection, and P2 = 30% Elephant grass + 60% Basal Concentrate + 10% soybeans groats formaldehyde protection. Supplementation of 10% soybean protected feeding in male thin tail sheep fattening ration had significant effect (P <0.05) on crude protein digestibility, nutrient value index and digested crude protein. The use of 10% of soybean protected 37% formaldehyde protected soy by 1% of the dry weight of the concentrate in thin tail fattening rations could improve protein digestibility, nutrient value index and abrasive proteins that can be ingested in vivo.

Lead phytoremediation potential of Vetiver grass: a hydroponic study

NASA Astrophysics Data System (ADS)

Pachanoor, D. S.; Andra, S. P.; Datta, R.; Sarkar, D.

2006-05-01

Lead (Pb) is a toxic heavy metal that is released into the environment from a variety of sources. Sources of Pb contamination in soils can be divided into three broad categories: industrial activities, such as mining and smelting processes, agricultural activities, such as application of insecticide and municipal sewage sludge, and urban activities, such as use of Pb in gasoline, paints, and other materials. Severe Pb contamination of soils may cause a variety of environmental problems, including loss of vegetation, groundwater contamination and Pb toxicity in plants, animals and humans. The use of plants to remove toxic metals from soils (phytoremediation) is fast emerging as an acceptable strategy for cost-effective and environmentally sound remediation of contaminated soils. The objective of this study was to gain insight into the lead uptake potential and biochemical stress response mechanism in vetiver grass (Vetiveria zizanioides L.) upon exposure to Pb in contaminated soils. We investigated the effect of increasing concentrations of Pb on vetiver grass grown in a hydroponic system. Plant response to the addition of phosphate in the presence of Pb was also studied. Biochemical stress response was studied by monitoring the activities of Superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes. The results indicated that exposure to Pb in the range of 0 ppm -1200 ppm had no significant negative effects on the growth of vetiver grass. There was no considerable decrease in vetiver biomass, implying the potential of this grass for Pb phytoremediation. The translocation of Pb from the root to the shoot was up to 20%. The SOD activity was in positive correlation with Pb concentrations in the solution, but no such trend was observed with GPx. In systems containing phosphate fertilizer, lead precipitated out immediately, thereby decreasing the soluble concentration of lead, resulting in less availability of Pb to the grass.

Dry matter intake, body condition score, and grazing behavior of nonlactating, pregnant dairy cows fed kale or grass once versus twice daily during winter.

PubMed

Rugoho, I; Edwards, G R

2018-01-01

The objective of this study was to examine the effect of wintering pregnant, nonlactating dairy cows outdoors on either kale or grass, fed in 1 [11 kg dry matter (DM) of kale or grass + 3 kg DM of baled barley straw offered in the morning] or 2 allocations (5.5 kg DM of kale or grass grazed + 1.5 kg DM of barley straw offered morning and afternoon) per day. The body condition score (BCS) gain over the 47-d winter feeding period was higher for grass-fed (0.5 BCS units) than kale-fed cows (0.3 BCS units), but was unaffected by feeding frequency. Forage DM utilization was higher for kale-fed (97%) than grass-fed cows (76%), leading to higher estimated dry matter intake (DMI) in kale-fed (10.7 kg of DM/cow per day) than grass-fed cows (7.7 kg of DM/cow per day). Forage DM utilization and estimated DMI were not affected by feeding frequency. Prehension bite rate was greater for grass-fed (37.3 bites/min) than kale-fed cows (7.6 bites/min), but more mastication bites were required for kale-fed cows. Cumulative DMI after 2, 3, and 6 h was greater in cows allocated forage once than twice a day and for kale than grass after 3 and 6 h. Mean eating time was greater for cows offered forage once (477 min) than twice (414 min) per day. In conclusion, increasing feeding frequency from once to twice per day decreased the intake rate within the first 6 h after allocation, but did not affect total daily DMI, DM utilization or BCS gain. Thus, moving cows more frequently would not have any significant advantage. It may increase labor requirements, thereby creating a more challenging wintering management than feeding once per day. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Dose-response relationship of a new Timothy grass pollen allergoid in comparison with a 6-grass pollen allergoid.

PubMed

Pfaar, O; Hohlfeld, J M; Al-Kadah, B; Hauswald, B; Homey, B; Hunzelmann, N; Schliemann, S; Velling, P; Worm, M; Klimek, L

2017-11-01

Subcutaneous allergen immunotherapy with grass pollen allergoids has been proven to be effective and safe in the treatment of patients with allergic rhinoconjunctivitis. Based on the extensive cross-reactivity among Pooideae species, it has been suggested that grass pollen extracts could be prepared from a single species, rather than from a multiple species mixture. To find the optimal dose of a Phleum pratense (P. pratense) allergoid preparation and compare its efficacy and safety to a 6-grass pollen allergoid preparation. In this double-blind, placebo-controlled study (EudraCT: 2011-000674-58), three doses of P. pratense allergoid (1800 therapeutic units (TU), standard-dose 6000 TU and 18 000 TU) were compared with placebo and the marketed 6-grass pollen allergoid (6000 TU). In a pre-seasonal dosing regimen, 102 patients were randomized to five treatment groups and received nine subcutaneous injections. The primary efficacy endpoint was the change in weal size (late-phase reaction [LPR]) in response to the intracutaneous testing (ICT) before and after treatment, comparing the active allergoids to placebo. Secondary outcomes were the change in Total Nasal Symptom Score (TNSS) assessed in the allergen exposure chamber (AEC), the changes in P. pratense-serum-specific IgG 4 and the incidence of adverse events (AEs). All three doses of the P. pratense and the 6-grass pollen allergoid preparations were significantly superior to placebo for the primary outcome, whereas there were no significant differences in the change in TNSS. Compared to the standard-dose, the high-dose of P. pratense did not produce any additional significant benefit, but showed a slight increase in AEs. Yet this increase in AEs was lower than for the 6-grass pollen preparation. The standard-dose of the new P. pratense allergoid was comparable to the marketed 6-grass pollen preparation at equal dose for the parameters measured. © 2017 The Authors. Clinical & Experimental Allergy Published by John Wiley & Sons Ltd.

Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

USGS Publications Warehouse

Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

2006-01-01

Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

Effects of climate on deer bone δ15N and δ13C: Lack of precipitation effects on δ15N for animals consuming low amounts of C 4 plants

NASA Astrophysics Data System (ADS)

Cormie, A. B.; Schwarcz, H. P.

1996-11-01

We have examined the relationship of bone collagen δ15N and δ13C to climatic variables, humidity, temperature, and amount of precipitation using fifty-nine specimens of North American white-tailed deer ( Odocoileus virginianus) from forty-six different locations. In previous studies of African mammals there was a significant correlation between bone collagen δ15N and local amount of precipitation. Results presented here similarly show an increase in δ15N with decreasing amount of precipitation but only for 25% of the animals, namely those consuming more than 10% C 4 plants. These animals also exhibited a significant correlation between δ13C and temperature which mirrors previous observations for grasses suggesting that these deer consume grasses during times of population and nutrient stress. In contrast, even in dry areas containing high proportions of C 4 grasses, the majority of the deer had consumed low amounts of C 4 plants and these deer did not have δ15N which correlate with amount of precipitation. Only when deer deviated from their normal feeding pattern by consuming C 4 plants or grasses did their δ15N correlate with amount of rainfall. For these animals, consumption of C 4 plants or grasses may signal conditions of water and nutrient stress. An increase in δ15N of bone collagen may result from combined effects from excretion of concentrated urine (to conserve water) and increased internal recycling of nitrogen (to conserve nitrogen).

Structural practices for controlling sediment transport from erosion

NASA Astrophysics Data System (ADS)

Gabriels, Donald; Verbist, Koen; Van de Linden, Bruno

2013-04-01

Erosion on agricultural fields in the hilly regions of Flanders, Belgium has been recognized as an important economical and ecological problem that requires effective control measures. This has led to the implementation of on-site and off-site measures such as reduced tillage and the installation of grass buffers trips, and dams made of vegetative materials. Dams made out of coir (coconut) and wood chips were evaluated on three different levels of complexity. Under laboratory conditions, one meter long dams were submitted to two different discharges and three sediment concentrations under two different slopes, to assess the sediment delivery ratios under variable conditions. At the field scale, discharge and sediment concentrations were monitored under natural rainfall conditions on six 3 m wide plots, of which three were equipped with coir dams, while the other three served as control plots. The same plots were also used for rainfall simulations, which allowed controlling sediment delivery boundary conditions more precisely. Results show a clear advantage of these dams to reduce discharge by minimum 49% under both field and laboratory conditions. Sediment delivery ratios (SDR) were very small under laboratory and field rainfall simulations (4-9% and 2% respectively), while larger SDRs were observed under natural conditions (43%), probably due to the small sediment concentrations (1-5 g l-1) observed and as such a larger influence of boundary effects. Also a clear enrichment of larger sand particles (+167%) could be observed behind the dams, showing a significant selective filtering effect.

Effects of flood inundation and invasion by Phalaris arundinacea on nitrogen cycling in an Upper Mississippi River floodplain forest

USGS Publications Warehouse

Swanson, Whitney; DeJager, Nathan R.; Strauss, Eric A.; Thomsen, Meredith

2017-01-01

Although floodplains are thought to serve as important buffers against nitrogen (N) transport to aquatic systems, frequent flooding and high levels of nutrient availability also make these systems prone to invasion by exotic plant species. Invasive plants could modify the cycling and availability of nutrients within floodplains, with effects that could feedback to promote the persistence of the invasive species and impact N export to riverine and coastal areas. We examined the effect of flooding on soil properties and N cycling at a floodplain site in Pool 8 of the Upper Mississippi River with 2 plant communities: mature native forest (Acer saccharinum) and patches of an invasive grass (Phalaris arundinacea). Plots were established within each vegetation type along an elevation gradient and sampled throughout the summers of 2013 and 2014. Spatial trends in flooding resulted in higher soil organic matter, porosity, and total nitrogen and carbon in low elevations. Nutrient processes and NH4+ and NO3− availability, however, were best explained by vegetation type and time after flooding. Phalaris plots maintained higher rates of nitrification and higher concentrations of available NH4+ and NO3−. These results suggest that invasion by Phalarismay make nitrogen more readily available and could help to reinforce this species' persistence in floodplain wetlands. They also raise the possibility that Phalaris may decrease floodplain N storage capacity and influence downstream transport of N to coastal zones.

Complementarity among four highly productive grassland species depends on resource availability.

PubMed

Roscher, Christiane; Schmid, Bernhard; Kolle, Olaf; Schulze, Ernst-Detlef

2016-06-01

Positive species richness-productivity relationships are common in biodiversity experiments, but how resource availability modifies biodiversity effects in grass-legume mixtures composed of highly productive species is yet to be explicitly tested. We addressed this question by choosing two grasses (Arrhenatherum elatius and Dactylis glomerata) and two legumes (Medicago × varia and Onobrychis viciifolia) which are highly productive in monocultures and dominant in mixtures (the Jena Experiment). We established monocultures, all possible two- and three-species mixtures, and the four-species mixture under three different resource supply conditions (control, fertilization, and shading). Compared to the control, community biomass production decreased under shading (-56 %) and increased under fertilization (+12 %). Net diversity effects (i.e., mixture minus mean monoculture biomass) were positive in the control and under shading (on average +15 and +72 %, respectively) and negative under fertilization (-10 %). Positive complementarity effects in the control suggested resource partitioning and facilitation of growth through symbiotic N2 fixation by legumes. Positive complementarity effects under shading indicated that resource partitioning is also possible when growth is carbon-limited. Negative complementarity effects under fertilization suggested that external nutrient supply depressed facilitative grass-legume interactions due to increased competition for light. Selection effects, which quantify the dominance of species with particularly high monoculture biomasses in the mixture, were generally small compared to complementarity effects, and indicated that these species had comparable competitive strengths in the mixture. Our study shows that resource availability has a strong impact on the occurrence of positive diversity effects among tall and highly productive grass and legume species.

Changes in Seagrass Species Composition in Northwestern Gulf of Mexico Estuaries: Effects on Associated Seagrass Fauna

PubMed Central

Ray, Brandon R.; Johnson, Matthew W.; Cammarata, Kirk; Smee, Delbert L.

2014-01-01

The objective of this study was to measure the communities associated with different seagrass species to predict how shifts in seagrass species composition may affect associated fauna. In the northwestern Gulf of Mexico, coverage of the historically dominant shoal grass (Halodule wrightii) is decreasing, while coverage of manatee grass (Syringodium filiforme) and turtle grass (Thalassia testudinum) is increasing. We conducted a survey of fishes, crabs, and shrimp in monospecific beds of shoal, manatee, and turtle grass habitats of South Texas, USA to assess how changes in sea grass species composition would affect associated fauna. We measured seagrass parameters including shoot density, above ground biomass, epiphyte type, and epiphyte abundance to investigate relationships between faunal abundance and these seagrass parameters. We observed significant differences in communities among three seagrass species, even though these organisms are highly motile and could easily travel among the different seagrasses. Results showed species specific relationships among several different characteristics of the seagrass community and individual species abundance. More work is needed to discern the drivers of the complex relationships between individual seagrass species and their associated fauna. PMID:25229897

The relative importance of different grass components in controlling runoff and erosion on a hillslope under simulated rainfall

NASA Astrophysics Data System (ADS)

Li, Changjia; Pan, Chengzhong

2018-03-01

The effects of vegetation cover on overland flow and erosion processes on hillslopes vary with vegetation type and spatial distribution and the different vegetation components, including the above- and below-ground biomass. However, few attempts have been made to quantify how these factors affect erosion processes. Field experimental plots (5 m × 2 m) with a slope of approximately 25° were constructed and simulated rainfall (60 mm hr-1) (Rainfall) and simulated rainfall combined with upslope overland flow (20 L min-1) (Rainfall + Flow) were applied. Three grass species were planted, specifically Astragalus adsurgens (A. adsurgens), Medicago sativa (M. sativa) and Cosmos bipinnatus (C. bipinnatus). To isolate and quantify the relative contributions of the above-ground grass parts (stems, litter cover and leaves) and the roots to reducing surface runoff and erosion, each of the three grass species was subjected to three treatments: intact grass control (IG), no litter or leaves (only the grass stems and roots were reserved) (NLL), and only roots remaining (OR). The results showed that planting grass significantly reduced overland flow rate and velocity and sediment yield, and the mean reductions were 21.8%, 29.1% and 67.1%, respectively. M. sativa performed the best in controlling water and soil losses due to its thick canopy and dense, fine roots. Grasses reduced soil erosion mainly during the early stage of overland flow generation. The above-ground grass parts primarily contributed to reducing overland flow rate and velocity, with mean relative contributions of 64% and 86%, respectively. The roots played a predominant role in reducing soil erosion, with mean contribution of 84%. Due to the impact of upslope inflow, overland flow rate and velocity and sediment yield increased under the Rainfall + Flow conditions. The results suggest that grass species on downslope parts of semi-arid hillslopes performed better in reducing water and soil losses. This study is beneficial for forage selection, allocation and management practices, such as forage harvesting, when implementing restoration strategies to control soil and water losses.

Estimates of spatial and temporal variation of energy crops biomass yields in the US

NASA Astrophysics Data System (ADS)

Song, Y.; Jain, A. K.; Landuyt, W.; Kheshgi, H. S.

2013-12-01

Perennial grasses, such as switchgrass (Panicum viragatum) and Miscanthus (Miscanthus x giganteus) have been identified for potential use as biomass feedstocks in the US. Current research on perennial grass biomass production has been evaluated on small-scale plots. However, the extent to which this potential can be realized at a landscape-scale will depend on the biophysical potential to grow these grasses with minimum possible amount of land that needs to be diverted from food to fuel production. To assess this potential three questions about the biomass yield for these grasses need to be answered: (1) how the yields for different grasses are varied spatially and temporally across the US; (2) whether the yields are temporally stable or not; and (3) how the spatial and temporal trends in yields of these perennial grasses are controlled by limiting factors, including soil type, water availability, climate, and crop varieties. To answer these questions, the growth processes of the perennial grasses are implemented into a coupled biophysical, physiological and biogeochemical model (ISAM). The model has been applied to quantitatively investigate the spatial and temporal trends in biomass yields for over the period 1980 -2010 in the US. The bioenergy grasses considered in this study include Miscanthus, Cave-in-Rock switchgrass and Alamo switchgrass. The effects of climate, soil and topography on the spatial and temporal trends of biomass yields are quantitatively analyzed using principal component analysis and GIS based geographically weighted regression. The spatial temporal trend results are evaluated further to classify each part of the US into four homogeneous potential yield zones: high and stable yield zone (HS), high but unstable yield zone (HU), low and stable yield zone (LS) and low but unstable yield zone (LU). Our preliminary results indicate that the yields for perennial grasses among different zones are strongly related to the different controlling factors. For example, the yield in HS zone is depended on soil and topography factors. However, the yields in HU zone are more controlled by climate factors, leading to a large uncertainty in yield potential of bioenergy grasses under future climate change.

Implications for Ophthalmic Formulations: Ocular Buffers Show Varied Cytotoxic Impact on Human Corneal-Limbal and Human Conjunctival Epithelial Cells.

PubMed

Schuerer, Nadine; Stein, Elisabeth; Inic-Kanada, Aleksandra; Pucher, Marion; Hohenadl, Christine; Bintner, Nora; Ghasemian, Ehsan; Montanaro, Jacqueline; Barisani-Asenbauer, Talin

2017-06-01

To investigate toxicity associated with buffers commonly used in topical ocular drug formulations using a human corneal-limbal epithelial (HCLE) and a human conjunctival epithelial (HCjE) cell model. HCLE and HCjE cells were incubated for 10, 30, or 60 minutes with 4 different buffers based on borate, citrate, phosphate, and Tris-HCl at 10, 50, and 100 mM concentrations. To detect possible delayed effects on cell viability, after 60 minutes of buffer incubation, cells were further incubated for 24 hours with a cell medium. Cell viability was determined using a colorimetric XTT-based assay. The morphology of cells was also investigated. HCjE cells showed more sensitivity to buffer incubation than HCLE cells. The 100 mM phosphate buffer displayed significant delayed effects on cell viability of HCLE 16.8 ± 4.8% and HCjE 39.2 ± 6.1% cells after 60 minutes of exposure (P < 0.05). HCjE cell viability was reduced after 60 minutes incubations with 50 and 100 mM citrate buffer to 42.8 ± 6.5% and 39.3 ± 7.9%, respectively, and even lower percentages at the delayed time point (both P < 0.05). HCLE cell morphology was distinctly altered by 100 mM phosphate and Tris buffers after 30 minutes, whereas HCjE cells already showed marked changes after 10 minutes of exposure to 100 mM citrate and phosphate buffers. We observed a time-dependent decrease of viability in both HCLE and HCjE cells exposed to higher buffer concentrations. Therefore, we propose further in vivo studies to translate these finding to humans to discern the real effects of the buffer concentration in eye drops on the ocular surface.

Implications for Ophthalmic Formulations: Ocular Buffers Show Varied Cytotoxic Impact on Human Corneal–Limbal and Human Conjunctival Epithelial Cells

PubMed Central

Schuerer, Nadine; Stein, Elisabeth; Inic-Kanada, Aleksandra; Pucher, Marion; Hohenadl, Christine; Bintner, Nora; Ghasemian, Ehsan; Montanaro, Jacqueline

2017-01-01

Purpose: To investigate toxicity associated with buffers commonly used in topical ocular drug formulations using a human corneal–limbal epithelial (HCLE) and a human conjunctival epithelial (HCjE) cell model. Methods: HCLE and HCjE cells were incubated for 10, 30, or 60 minutes with 4 different buffers based on borate, citrate, phosphate, and Tris-HCl at 10, 50, and 100 mM concentrations. To detect possible delayed effects on cell viability, after 60 minutes of buffer incubation, cells were further incubated for 24 hours with a cell medium. Cell viability was determined using a colorimetric XTT–based assay. The morphology of cells was also investigated. Results: HCjE cells showed more sensitivity to buffer incubation than HCLE cells. The 100 mM phosphate buffer displayed significant delayed effects on cell viability of HCLE 16.8 ± 4.8% and HCjE 39.2 ± 6.1% cells after 60 minutes of exposure (P < 0.05). HCjE cell viability was reduced after 60 minutes incubations with 50 and 100 mM citrate buffer to 42.8 ± 6.5% and 39.3 ± 7.9%, respectively, and even lower percentages at the delayed time point (both P < 0.05). HCLE cell morphology was distinctly altered by 100 mM phosphate and Tris buffers after 30 minutes, whereas HCjE cells already showed marked changes after 10 minutes of exposure to 100 mM citrate and phosphate buffers. Conclusions: We observed a time-dependent decrease of viability in both HCLE and HCjE cells exposed to higher buffer concentrations. Therefore, we propose further in vivo studies to translate these finding to humans to discern the real effects of the buffer concentration in eye drops on the ocular surface. PMID:28399036

Silymarin inhibits adipogenesis in the adipocytes in grass carp Ctenopharyngodon idellus in vitro and in vivo.

PubMed

Xiao, Peizhen; Yang, Zhou; Sun, Jian; Tian, Jingjing; Chang, Zhiguang; Li, Xuexian; Zhang, Baotong; Ye, Yuantu; Ji, Hong; Yu, Ermeng; Xie, Jun

2017-12-01

In this study, two experiments were performed to explore the function of silymarin in adipogenesis in grass carp (Ctenopharyngodon idellus) using in vitro and in vivo models. In experiment 1, differentiated grass carp pre-adipocytes were treated with silymarin for 6 days. Treatment with 100 μg mL -1 silymarin (SM100 group) significantly reduced triglyceride accumulation at day 6. The adipogenic gene expression levels of PPARγ, C/EBPα, SREBP1c, FAS, SCD1, and LPL, and the protein expression level of PPARγ were significantly down-regulated in the SM100 group. Additionally, the SM100 group had significantly lower reactive oxygen species production and reduced glutathione contents compared with the control in vitro. In experiment 2, the juvenile grass carp (mean body weight= 27.4 ± 0.17 g) were fed six isonitrogenous and isocaloric diets in a factorial design containing 0, 100, or 200 mg kg -1 silymarin (SM0, SM100, SM200) associated with either 4 or 8% lipid levels (low lipid, LL, and high lipid, HL, respectively) for 82 days. The results demonstrated that dietary silymarin supplementation significantly reduced the elevated intraperitoneal fat index in grass carp fed with high-lipid diets, and the gene expression of adipogenesis (PPARγ, FAS) when supplemented with dietary silymarin was notably lower than when no silymarin was supplemented under the high-lipid diets. Thus, our data suggest that silymarin suppressed lipid accumulation in grass carp both in vitro and in vivo, and the effect might be due to an influence on the expression of adipogenesis factors and ROS production partly associated with effects on antioxidant capability.

Woody-grass ratios in a grassy arid system are limited by multi-causal interactions of abiotic constraint, competition and fire.

PubMed

Nano, Catherine E M; Clarke, Peter J

2010-03-01

Predicting changes in vegetation structure in fire-prone arid/semi-arid systems is fraught with uncertainty because the limiting factors to coexistence between grasses and woody plants are unknown. We investigated abiotic and biotic factors influencing boundaries and habitat membership in grassland (Triodia or 'spinifex' grassland)-shrubland (Acacia aneura or 'mulga' shrubland) mosaics in semi-arid central Australia. We used a field experiment to test for the effects of: (1) topographic relief (dune/swale habitat), (2) adult neighbour removal, and (3) soil type (sand/clay) on seedling survival in three shrub and two grass species in reciprocal field plantings. Our results showed that invasion of the shrubland (swale) by neighbouring grassland species is negated by abiotic limitations but competition limits shrubland invasion of the grassland (dune). All species from both habitats had significantly reduced survival in the grassland (dune) in the presence of the dominant grass (Triodia) regardless of soil type or shade. Further, the removal of the dominant grass allowed the shrubland dominant (A. aneura) to establish outside its usual range. Seedling growth and sexual maturation of the shrubland dominant (A. aneura) was slow, implying that repeated fire creates an immaturity risk for this non-sprouter in flammable grassland. By contrast, rapid growth and seed set in the grassland shrubs (facultative sprouters) provides a solution to fire exposure prior to reproductive onset. In terms of landscape dynamics, we argue that grass competition and fire effects are important constraints on shrubland patch expansion, but that their relative importance will vary spatially throughout the landscape because of spatial and temporal rainfall variability.

Oral administration of Lactobacillus paracasei NCC 2461 for the modulation of grass pollen allergic rhinitis: a randomized, placebo-controlled study during the pollen season.

PubMed

Nembrini, Chiara; Singh, Anurag; De Castro, Carlos Antonio; Mercenier, Annick; Nutten, Sophie

2015-01-01

The efficacy of Lactobacillus paracasei NCC 2461 in modulating allergic rhinitis was previously evaluated in two exploratory clinical studies. Oral administration with NCC 2461 reduced specific subjective symptoms following nasal provocation tests with controlled grass pollen allergen concentrations. Our aim was to confirm the anti-allergic effect of NCC 2461 in grass pollen allergic subjects exposed to natural doses of allergens during the pollen season. A double-blind, randomized, placebo-controlled, parallel study was conducted with 131 grass pollen allergic subjects from May to July 2012 in concomitance with the pollen season in Berlin. NCC 2461 or placebo was administered daily for an 8-week period to adult subjects with clinical history of allergic rhinitis to grass pollen, positive skin prick test and IgE to grass pollen. During the 8 weeks, symptoms and quality of life questionnaires were filled out, and plasma was collected for IgE analysis at screening and at the end of the intervention. All subjects were included within a 5-day interval, ensuring exposure to similar air pollen counts for each individual during the trial period. The results obtained show that symptoms increased with pollen loads, confirming a natural exposure to the allergen and presence of pollen-induced allergic rhinitis in the subjects. However, no significant differences were observed in allergic rhinitis symptoms scores, quality of life, or specific IgE levels between subjects receiving NCC 2461 as compared to placebo administration. In contrast to previous findings, oral administration of NCC 2461 did not show a beneficial effect on allergic rhinitis in a field trial. The influence of study design, allergen exposure and intervention window on the efficacy of NCC 2461 in modulating respiratory allergy should be further evaluated.

Effects of grazing management and buffer strips on metal runoff from pastures fertilized with poultry litter

USDA-ARS?s Scientific Manuscript database

Metal runoff from fields fertilized with poultry litter may pose a threat to aquatic systems. Buffer strips have been added to fields to reduce nutrients and solids runoff. However, scant information exists on the effects of buffer strips combined with grazing management strategies on metal runoff f...

Effects of riparian buffers on hydrology of northern seasonal ponds

Treesearch

Randall K. Kolka; Brian J. Palik; Daniel P. Tersteeg; James C. Bell

2011-01-01

Although seasonal ponds are common in northern, glaciated, forested landscapes, forest management guidelines are generally lacking for these systems. The objective of this study was to determine the effect of riparian buffer type on seasonal pond hydrology following harvest of the adjacent upland forest. A replicated block design consisting of four buffer treatments...

High precipitation and seeded species competition reduce seeded shrub establishment during dryland restoration.

PubMed

Rinella, Matthew J; Hammond, Darcy H; Bryant, Ana-Elisa M; Kozar, Brian J

2015-06-01

Drylands comprise 40% of Earth's land mass and are critical to food security, carbon sequestration, and threatened and endangered wildlife. Exotic weed invasions, overgrazing, energy extraction, and other factors have degraded many drylands, and this has placed an increased emphasis on dryland restoration. The increased restoration focus has generated a wealth of experience, innovations and empirical data, yet the goal of restoring diverse, native, dryland plant assemblages composed of grasses, forbs, and shrubs has generally proven beyond reach. Of particular concern are shrubs, which often fail to establish or establish at trivially low densities. We used data from two Great Plains, USA coal mines to explore factors regulating shrub establishment. Our predictor data related to weather and restoration (e.g., seed rates, rock cover) variables, and our response data described shrub abundances on fields of the mines. We found that seeded non-shrubs, especially grasses, formed an important competitive barrier to shrub establishment: With every one standard deviation increase in non-shrub seed rate, the probability shrubs were present decreased ~0.1 and shrub cover decreased ~35%. Since new fields were seeded almost every year for > 20 years, the data also provided a unique opportunity to explore effects of stochastic drivers (i.e., precipitation, year effects). With every one standard deviation increase in precipitation the first growing season following seeding, the probability shrubs were present decreased ~0.07 and shrub cover decreased ~47%. High precipitation appeared to harm shrubs by increasing grass growth/competition. Also, weak evidence suggested shrub establishment was better in rockier fields where grass abundance/competition was lower. Multiple lines of evidence suggest reducing grass seed rates below levels typically used in Great Plains restoration would benefit shrubs without substantially impacting grass stand development over the long term. We used Bayesian statistics to estimate effects of seed rates and other restoration predictors probabilistically to allow knowledge of the predictors' effects to be refined through time in an adaptive management framework. We believe this framework could improve restoration planning in a variety of systems where restoration outcomes remain highly uncertain and ongoing restoration efforts are continually providing new data of value for reducing the uncertainty.

Effect of frame size and season on enteric methane (CH4) and carbon dioxide (CO2)emissions in Angus brood cows grazing native tall-grass prairie in central Oklahoma USA

USDA-ARS?s Scientific Manuscript database

Effect of frame size and season on enteric methane (CH4) and carbon dioxide (CO2) emissions in Angus brood cows grazing native tall-grass prairie in central Oklahoma, USA J.P.S. Neel USDA ARS, El Reno, OK A reduction in enteric CH4 production in ruminants is associated with improved production effic...

The effect of essential oils on microbial composition and quality of grass carp (Ctenopharyngodon idellus) fillets during chilled storage.

PubMed

Huang, Zhan; Liu, Xiaochang; Jia, Shiliang; Zhang, Longteng; Luo, Yongkang

2018-02-02

Antimicrobial and antioxidant effects of essential oils (oregano, thyme, and star anise) on microbial composition and quality of grass carp fillets were investigated. Essential oils treatment was found to be effective in inhibiting microbial growth, delaying lipid oxidation, and retarding the increase of TVB-N, putrescine, hypoxanthine, and K-value. Based on sensory analysis, shelf-life of grass carp fillets was 6days for control and 8days for treatment groups. Among the essential oils, oregano essential oil exhibited the highest antimicrobial and antioxidant activities. GC-MS analysis of essential oils components revealed that carvacrol (88.64%) was the major component of oregano essential oil. According to the results of high-throughput sequencing, Aeromonas, Glutamicibacter, and Aequorivita were the predominant microbiota in fresh control samples. However, oregano essential oil decreased the relative abundance of Aeromonas, while thyme and star anise essential oils decreased the relative abundance of Glutamicibacter and Aequorivita in fresh treated samples. The microbial composition of both control and treatment groups became less diverse as storage time increased. Aeromonas and Pseudomonas were dominant in spoiled samples and contributed to fish spoilage. Compared to the control, essential oils effectively inhibited the growth of Aeromonas and Shewanella in grass carp fillets during chilled storage. Copyright © 2017 Elsevier B.V. All rights reserved.

Noise characteristics of grass-trimming machine engines and their effect on operators.

PubMed

Mallick, Zulquernain; Badruddin, Irfan Anjum; Khaleed Hussain, M T; Salman Ahmed, N J; Kanesan, Jeevan

2009-01-01

Over the last few years, interaction of humans with noisy power-driven agricultural tools and its possible adverse after effects have been realized. Grass-trimmer engine is the primary source of noise and the use of motorized cutter, spinning at high speed, is the secondary source of noise to which operators are exposed. In the present study, investigation was carried out to determine the effect of two types of grass-trimming machine engines (SUM 328 SE and BG 328) noise on the operators in real working environment. It was found that BG-328 and SUM-328 SE produced high levels of noise, of the order of 100 and 105 dB(A), respectively, to which operators are exposed while working. It was also observed that situation aggravates when a number of operators simultaneously operate resulting in still higher levels of noise. Operators should be separated 15 meters from each other in order to avoid the combined level of noise exposure while working with these machines. It was found that SPL, of the grass-trimmer machine engines (BG-328 and SUM-328 SE), were higher than the limit of noise recommended by ISO, NIOSH, and OSHA for an 8-hour workday. Such a high level of noise exposure may cause physiological and psychological problems to the operators in long run.

The effect of surfactant on headspace single drop microextraction for the determination of some volatile aroma compounds in citronella grass and lemongrass leaves by gas chromatography

USDA-ARS?s Scientific Manuscript database

A rapid method for the determination of some volatile aromatic compounds (VACs), including citronellal, citronellol, neral, geranial, geraniol, and eugenol in citronella grass and lemongrass leaves, was developed using surfactant as a surface tension modifier while performing headspace single drop m...

Evidence for an Alternative Landscape Potential in California Annual Rangelands

Treesearch

Richard J. King

1989-01-01

The basic tenet of annual range management in California is that perennial grasses are unable to effectively compete with the naturalized alien annual species. Evidence from the field in northern California is not consistent with this thinking. An alternative view that perennial grasses are restricted in importance from overgrazing and excessive rest is presented....

EFFECTS OF FOOD AVAILABILITY ON LIPID CLASS COMPOSITION AND C AND N ACCUMULATION IN HEPATOPANCREATIC, OVARIAN AND EMBRYONIC TISSUES OF THE GRASS SHRIMP PALAEMONETES PUGIO: A LABORATORY STUDY

EPA Science Inventory

In a laboratory experiment, limited food availability caused severe mortality and reduced growth of adult female grass shrimp Palaemonetes pugio. However, reproduction, measured by % gravid females and clutch size, was unaffected by food availability. It appears that female shrim...

Restoration of native plant communities in a Hawaiian dry lowland ecosystem dominated by the invasive grass Megathyrsus maximus

Treesearch

Selita A. Ammondt; Creighton M. Litton; Lisa M. Ellsworth; James K. Leary

2012-01-01

How does a highly degraded Hawaiian tropical dry lowland ecosystem dominated by the non-native invasive Megathyrsus maximus (guinea grass) respond to different restoration treatments (three native species outplanting treatments; four native broadcast seed treatments)? What effect do restoration treatments have on invasive and native species...

Effects of sampling time, cultivar, and methodology on water- and ethanol-soluble carbohydrate profiles of three cool-season grasses in Central Kentucky

USDA-ARS?s Scientific Manuscript database

Cool-season grasses (CSG) accumulate variable amounts of water-soluble carbohydrates (WSC, mono- and disaccharides and fructans), depending on climate, time of day and year, and genotype. Fructan concentrations in CSG are sometimes estimated as the difference between concentrations of WSC and ethano...

Use of a mixed sericea lespedeza and grass pasture system for control of gastrointestinal nematodes in lambs and kids

USDA-ARS?s Scientific Manuscript database

Because of a high prevalence of anthelmintic resistance and consumer demand for chemical free meat products, management tools to minimize the need for deworming are needed. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) in a mixed grass or a pure forage system for ...

Managing soil nitrogen to restore annual grass-infested plant communities: Effective strategy or incomplete framework?

Treesearch

J. J. James; R. E. Drenovsky; T. A. Monaco; M. J. Rinella

2011-01-01

Theoretical and empirical work has established a positive relationship between resource availability and habitat invasibility. For nonnative invasive annual grasses, similar to other invasive species, invader success has been tied most often to increased nitrogen (N) availability. These observations have led to the logical assumption that managing soils for low N...

Surface Erosion Control Techniques on Newly Constructed Forest Roads

Treesearch

Johnny M. Grace; John Wilhoit; Robert Rummer; Bryce Stokes

1999-01-01

A newly constructed forest road was treated with three erosion control treatments: wood excelsior erosion mat, native grass species, and exotic grass species. The study evaluates treatment methods on the basis of sediment reduction and runoff volume reduction compared to no treatment. The erosion mat treatment was most effective in mitigating erosion losses with a 98...

Cumulative effects of sewage sludge and effluent mixture application on soil properties of a sandy soil under a mixture of star and kikuyu grasses in Zimbabwe

NASA Astrophysics Data System (ADS)

Madyiwa, S.; Chimbari, M.; Nyamangara, J.; Bangira, C.

Although sewage effluent and sludge provides nutrients for plant growth, its continual use over extended periods can result in the accumulation of heavy metals in soils and in grass to levels that are detrimental to the food chain. This study was carried in 2001 out at Firle farm, owned by the Municipality of Harare, to assess heavy metal loading on a sandy soil and uptake of the metals by pasture grass consisting of a mixture of Cynodon nlemfuensis (star grass) and Pennisetum clandestinum Chiov (kikuyu grass) following sewage effluent and sludge application for 29 years. Firle Farm receives treated effluent and sludge emanating from domestic and industrial sources. Soil and grass samples were taken from the study area, consisting of 3 ha of non-irrigated area (control) and 1.3 ha of irrigated area. Both the soil and grass samples were tested for Cu, Zn, Ni and Pb using atomic absorption spectrophotometry. Sewage sludge addition resulted in high levels of soil pollution, especially in the 20 cm horizon, in the irrigated area when compared to the control. Grasses took up moderate levels of Cu and Zn, and limited levels of Pb. Nickel was not detectable in grasses despite high levels in the irrigated soil. Copper uptake was several times higher than the suggested potentially toxic level of 12 mg/kg [Soil Science Society of America, Micronutrients in agriculture, second ed., Wisconsin, USA, 1991]. Lead uptake averaged 1.0 mg/kg, which was below 10 mg/kg the suggested limit for agronomic crops [E.M. Seaker, Zinc, copper, cadmium and lead in minespoil, water and plants from reclaimed mine land amended with sewage sludge, 1991]. Cu and Zn showed relatively higher mobility down the soil profile than Ni and Pb. Even then, the concentrations in the lower soil layers were very small, suggesting that the metals were unlikely to contaminate groundwater. There was no direct correlation between metal levels in soils and grasses. It was postulated that it is the bio-available metal fraction in the soil that is correlated to plant uptake. The grasses appeared healthy even though they contained moderately high levels of Zn and Cu. This raises the possibility of beef animals grazing on ;healthy; looking grass that has very high concentrations of heavy metals. The fact that the total metal concentrations in the experimental soil were very high but did not cause any toxicity symptoms to the grass suggested that the limit soil concentration do not necessarily imply toxicity to all plants. However, limit concentrations are set not only for plant growth, but also for the protection of soil microorganisms and the latter are more sensitive to heavy metal pollution.

Effect of ZnO seed layer on the morphology and optical properties of ZnO nanorods grown on GaN buffer layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nandi, R., E-mail: rajunandi@iitb.ac.in; Mohan, S., E-mail: rajunandi@iitb.ac.in; Major, S. S.

2014-04-24

ZnO nanorods were grown by chemical bath deposition on sputtered, polycrystalline GaN buffer layers with and without ZnO seed layer. Scanning electron microscopy and X-ray diffraction show that the ZnO nanorods on GaN buffer layers are not vertically well aligned. Photoluminescence spectrum of ZnO nanorods grown on GaN buffer layer, however exhibits a much stronger near-band-edge emission and negligible defect emission, compared to the nanorods grown on ZnO buffer layer. These features are attributed to gallium incorporation at the ZnO-GaN interface. The introduction of a thin (25 nm) ZnO seed layer on GaN buffer layer significantly improves the morphology andmore » vertical alignment of ZnO-NRs without sacrificing the high optical quality of ZnO nanorods on GaN buffer layer. The presence of a thick (200 nm) ZnO seed layer completely masks the effect of the underlying GaN buffer layer on the morphology and optical properties of nanorods.« less

Alkaloids of Stipa robusta (sleepygrass) infected with an Acremonium endophyte.

PubMed

Petroski, R J; Powell, R G; Clay, K

1992-01-01

Stipa robusta (= Stipa vaseyi) is a perennial grass found in certain areas of the southwestern United States. It is commonly known as sleepygrass, as horses that ingest this grass may become profoundly somnolent or stuporous for periods of time lasting up to several days. In an attempt to determine the active principle(s), fractionation of a methanolic extract of sleepygrass infected with an Acremonium endophyte has yielded lysergic acid amide (20 micrograms/g dry wt), isolysergic amide (8), 8-hydroxylsergic acid amide (0.3), ergonovine (7), chanoclavine-I (15), and N-formylloline (18). Related alkaloids have been found in many endophyte-infected grasses. The dominant alkaloid constituent in sleepygrass, lysergic acid amide, has not previously been identified in a grass in such high concentration. Lysergic acid amide is likely to be the basis for the extreme sedative effects on animals, given past pharmacological work on the compound from the ergot fungus Claviceps paspali.

Optimization of gelatine extraction from grass carp (Catenopharyngodon idella) fish skin by response surface methodology.

PubMed

Kasankala, Ladislaus M; Xue, Yan; Weilong, Yao; Hong, Sun D; He, Qian

2007-12-01

To establish the optimum gelatine extraction conditions from grass carp fish skin, response surface methodology (RSM) was adopted in this study. The effects of concentration of HCl (%, A), pre-treatment time (h, B), extraction temperature ( degrees C, C) and extraction time (h, D) were studied. The responses were yield (%) and gel strength (g). A=1.19%, B=24 h, C=52.61 degrees C and D=5.12h were determined as the optimum conditions while the predicted responses were 19.83% yield and 267 g gel strength. Gelling and melting points were 19.5 degrees C and 26.8 degrees C, respectively. Moreover, grass carp gelatine showed high contents of imino acids (proline and hydroxyproline) 19.47%. RSM provided a powerful tool to optimize the extraction parameters and the results may be adapted for industrial extraction of gelatine from grass carp fish skins.

Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer x Spanish goats.

PubMed

Puchala, R; Animut, G; Patra, A K; Detweiler, G D; Wells, J E; Varel, V H; Sahlu, T; Goetsch, A L

2012-08-01

Twenty-four yearling Boer × Spanish wethers were used to assess effects of different forages, either fresh (Exp. 1) or as hay (Exp. 2), on feed intake, digestibilities, heat production, and ruminal methane emission. Treatments were: 1) Sericea lespedeza (SER; Lespedeza cuneata), a legume high in condensed tannins (CT; 20% and 15% in fresh forage and hay, respectively), 2) SER supplemented with polyethylene glycol (SER-PEG; 25 g/d), 3) alfalfa (Medicago sativa), a legume low in CT (ALF), and 4) sorghum-sudangrass (Sorghum bicolor), a grass low in CT (GRASS). Experiments were 22 d, which included 16 d for acclimatization followed by a 6-d period for fecal and urine collection, and gas exchange measurement (last 2 d). Intake of OM was 867, 823, 694, and 691 g/d (SEM = 20.1) with fresh forage, and 806, 887, 681, and 607 g/d with hay for SER, SER-PEG, ALF, and GRASS, respectively (SEM = 46.6). Apparent total tract N digestion was greater for SER-PEG vs. SER (P < 0.001) with fresh forage (46.3%, 66.5%, 81.7%, and 73.2%; SEM = 1.71) and hay (49.7%, 71.4%, 65.4%, and 54.8% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.57). Intake of ME was similar among treatments with fresh forage (8.24, 8.06, 7.42, and 7.70 MJ/d; SEM = 0.434) and with hay was greater for SER-PEG than ALF (P < 0.03) and GRASS (P < 0.001) (8.63, 10.40, 8.15, and 6.74 MJ/d for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.655). The number of ciliate protozoa in ruminal fluid was least for SER with fresh forage (P < 0.01) (9.8, 20.1, 21.0, and 33.6 × 10(5)/ml; SEM = 2.76) and hay (P < 0.02) (6.3, 11.4, 13.6, and 12.5 × 10(5)/ml for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.43). Methane emission as a percentage of DE intake was lower (P < 0.01) for SER vs. ALF and GRASS with fresh forage (6.6, 8.3, 9.4, and 9.2%; SEM = 0.64) and hay (4.3, 4.9, 6.4, and 6.7% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.38). In summary, methane emission in this short-term experiment was similar between a legume and grass low in CT as fresh forage and hay. The CT in SER markedly decreased N digestibility and elicited a moderate decline in ruminal methane emission. Supplementation with PEG alleviated the effect of CT on N digestibility but not ruminal methane emission, presumably because of different modes of action. In conclusion, potential of using CT-containing forage as a means of decreasing ruminal methane emission requires further study, such as with longer feeding periods.

Physiological and morphological effects of high water tables on early growth of giant reed ( Arundo donax), elephant grass ( Pennisetum purpureum), energycane and sugarcane ( Saccharum spp.)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jennewein, Stephen Peter

Here, an increasing demand for renewable energy sources has spurred interest in high-biomass crops used for energy production. Species potentially well-suited for biofuel production in the seasonally wet organic Everglades Agricultural Area (EAA) of Florida include giant reed ( Arundo donax), elephant grass ( Pennisetum Purpureum), energycane ( Saccharum spp.), and sugarcane ( Saccharum spp.). The objectives in this study were to evaluate the role of fluctuating water tables on the morphology, physiology, and early season growth of these four genotypes. The candidate genotypes were grown in a greenhouse under three water table depths, defined by distance of the watermore » table from the soil surface: two constant water tables (-16 cm and -40 cm) along with a flood cycle (2 weeks of flood to the soil level followed by 2 weeks at -40 cm from the soil level). The genotypes included CP 89-2143 (sugarcane), L 79-1002 (energycane), Merkeron (elephant grass), and wild type (giant reed). The experiment was repeated for plant cane, first ratoon, and successive plant cane crop cycles. Reductions in dry matter yield were observed among genotypes subjected to the -40 cm drained, periodically flooded (40F) water table relative to the -40 cm constant (40C) or -16 cm constant (16C). Plant cane dry weights were reduced by 37% in giant reed, 52% in elephant grass, 42% in energycane, and 34% in sugarcane in the 40F compared to 40C water table treatments. Similarly, in the first ratoon crop dry weights were reduced by 29% in giant reed, 42% in elephant grass, 27% in energycane, and 62% in sugarcane. In plant cane and successive plant cane, average total dry weight was greatest for elephant grass whereas ratoon total dry weight was greatest for energycane. Genotype had more pronounced effects on physiological attributes than water table including the highest stomatal conductance and SPAD values in giant reed, and the highest stalk populations in elephant grass and energycane. Aerenchyma presence and volume increased under higher water tables with elephant grass having the greatest aerenchyma production. Because of the high yields and stalk populations in energycane and elephant grass for all crop stages seen in this study, these two genotypes show potential for bioenergy production in the EAA, but field trials are recommended to confirm this.« less

25 CFR 309.12 - What are examples of basketry that are Indian products?

Code of Federal Regulations, 2011 CFR

2011-04-01

..., spruce root, rye grass, sweet grass, yucca, bear grass, beach grass, rabbit brush, fiber, maidenhair fern..., pine needle/raffia effigy baskets, oak splint and braided sweet grass fancy baskets, birchbark containers, baleen baskets, rye grass dance fans, brown ash strawberry baskets, sumac wedding baskets, cedar...

25 CFR 309.12 - What are examples of basketry that are Indian products?

Code of Federal Regulations, 2010 CFR

2010-04-01

..., spruce root, rye grass, sweet grass, yucca, bear grass, beach grass, rabbit brush, fiber, maidenhair fern..., pine needle/raffia effigy baskets, oak splint and braided sweet grass fancy baskets, birchbark containers, baleen baskets, rye grass dance fans, brown ash strawberry baskets, sumac wedding baskets, cedar...

Urban Runoff: Model Ordinances for Aquatic Buffers

EPA Pesticide Factsheets

Aquatic Buffers serve as natural boundaries between local waterways and existing development. The model and example ordinaces below provide suggested language or technical guidance designed to create the most effective stream buffer zones possible.

Carbamylated monomeric allergoids as a therapeutic option for sublingual immunotherapy of dust mite- and grass pollen-induced allergic rhinoconjunctivitis: a systematic review of published trials with a meta-analysis of treatment using Lais® tablets.

PubMed

Mösges, R; Ritter, B; Kayoko, G; Allekotte, S

2010-10-01

Lais® allergoid tablets contain allergens that are modified by carbamylation. Due to their modified chemical structure, they are suitable for sublingual immunotherapy (SLIT) (13, 16, 17, 24). Based on their small molecule size of 12 to 40 kDa, they can be easily absorbed via the oral mucosa (1). In this review, we studied the efficacy of SLIT with carbamylated monomeric allergoid tablets in the treatment of grass pollen- and dust mite-induced allergic rhinoconjunctivitis on the basis of symptom and medication score improvements. Following a selective internet and databank search, six trials-some placebo-controlled-regarding the treatment of grass pollen- (n = 266) and dust mite-induced (n = 241) allergic rhinoconjunctivitis were used to draw conclusions regarding the clinical efficacy of allergoid tablets. The primary endpoints in these trials were decreases in the need for allergy medications and/or reductions in the occurrence of rhinoconjunctivitis symptoms. Data was recorded from patient diaries regarding their symptoms and medications used and conclusions were then drawn about the effectiveness and tolerabieity of Lais® tablets. The average improvement in symptom score in three trials of grass pollen allergy treatment was 34% in comparison to the placebo group. The treatment of dust mite-induced rhinoconjunctivitis produced an average symptom score improvement of 22% compared to the placebo or control groups. The intake of symptomatic rescue medication during allergoid tablet therapy declined. Treatment of grass pollen allergies and dust mite-induced rhinoconjunctivitis showed an average medication score improvement of 49% and 24%, respectively. Few side effects were documented in the trials and predominantly local effects were observed. Severe systemic side effects did not occur. On the basis of the trial results summarized in this review, we suggest that SLIT using Lais® sublingual tablets is an effective and well-tolerated form of treatment.

Soil nutrients and liming on dry weight yields and forage quality of Signal grass (Brachiaria decumbens Stapf.), grown on Korat soil series (oxic paleustults) in northeast Thailand.

PubMed

Pholsen, Suradej

2010-07-01

This experiment was carried out at Khon Kaen University Experimental Farm, Khon Kaen University, Thailand during the 2004-2005 aiming to investigate effect of phosphorus (P) and dolomite levels on dry weight yields (DWYs) and forage quality of Signal grass. A 4x3 factorial arranged in a Randomized Complete Block Design (RCBD) was used. Four P levels were: 0, 100, 200 and 400 kg P2O5 ha-1 and three dolomite levels were: 0, 625 and 2,500 kg ha-1. The Signal grass plants were grown on Korat soil series, (Oxic Paleustults). A quadrat with a dimension of 50x50 cm was used for grass yield harvests. Crude Protein (CP), Acid Detergent Fibre (ADF), Neutral Detergent Fibre (NDF) and Dry Matter Degradability (DMD) contents were determined. Tissues phosphorus and calcium contents were also analysed. The results showed that an increase in dolomite levels increased soil pH from 4.4 to 5.1 for levels 1 and 3, respectively. An increase in P levels increased available soil P from 4.56 to 28.38 ppm for levels 1 and 4, respectively. For the first year experiment, dolomite levels had no significant effect on DWYs, whilst P levels significantly increased but only up to level 2. The 2-year average DWYs reached 11,368 kg ha-1 for level 4 of P. With the first year rainy season harvests, P levels had its significant effect on ADF and DMD up to level 2 but not with CP and NDF. For the dry season harvests, P and dolomite levels had no significant effects on forage quality. Dolomite levels had no significant effect on P and Ca contents of the Signal grass tissues but an increase in P levels increased P contents. P and Ca contents, in most cases, were higher for the dry season than the rainy season.

Vegetative buffer strips for reducing herbicide transport in runoff: effects of buffer width, vegetation, and season

USDA-ARS?s Scientific Manuscript database

The effect of vegetative buffer strip (VBS) width, vegetation, and season of the year on herbicide transport in runoff has not been well documented for runoff prone soils. A multi-year replicated plot-scale study was conducted on an eroded claypan soil with the following objectives: 1) assess the ef...

On Buffers and Boosters: Social Support for Negative and Positive Life Events.

ERIC Educational Resources Information Center

Sandler, Irwin N.

Social support has been studied in the context of its relationship to and effect on negative experiences. While this buffer aspect of social support is important, support may also play a satisfaction-enhancing role. Both the negative event-buffering and positive event-boosting effect of social support on students' satisfaction with their college…

Control of short-channel effects in InAlN/GaN high-electron mobility transistors using graded AlGaN buffer

NASA Astrophysics Data System (ADS)

Han, Tiecheng; Zhao, Hongdong; Peng, Xiaocan; Li, Yuhai

2018-04-01

A graded AlGaN buffer is designed to realize the p-type buffer by inducing polarization-doping holes. Based on the two-dimensional device simulator, the effect of the graded AlGaN buffer on the direct-current (DC) and radio-frequency (RF) performance of short-gate InAlN/GaN high-electron mobility transistors (HEMTs) are investigated, theoretically. Compared to standard HEMT, an enhancement of electron confinement and a good control of short-channel effect (SCEs) are demonstrated in the graded AlGaN buffer HEMT. Accordingly, the pinched-off behavior and the ability of gate modulation are significantly improved. And, no serious SCEs are observed in the graded AlGaN buffer HEMT with an aspect ratio (LG/tch) of about 6.7, much lower than that of the standard HEMT (LG/tch = 13). In addition, for a 70-nm gate length, a peak current gain cutoff frequency (fT) of 171 GHz and power gain cutoff frequency (fmax) of 191 GHz are obtained in the grade buffer HEMT, which are higher than those of the standard one with the same gate length.

How does altered precipitation and annual grass invasion affect plant N uptake in a native semi-arid shrub community?

NASA Astrophysics Data System (ADS)

Mauritz, M.; Lipson, D.; Cleland, E. E.

2012-12-01

Climate change is expected to alter precipitation patterns, which will change the timing and amount of plant resources. Precipitation patterns determine water and nitrogen (N) availability, because water stimulates microbial N turnover and N transport. In order for plants to utilize water and N, they must coincide with the phenology and meet physiological requirements of the plant. As resource supply shifts, differences in species' ability to acquire resources will affect plant community composition. Semiarid ecosystems, such as shrublands in Southern California, are particularly sensitive to shifts in precipitation because they are severely water limited. This study takes advantage of the altered phenology and resource demands presented by invasive annual grasses in a native semiarid shrubland. The goal is to understand how altered precipitation patterns affect plant N uptake. Rainfall levels were manipulated to 50% and 150% of ambient levels. It is expected that higher rainfall levels promote annual grass invasion because grasses have higher water and N requirements and begin to grow earlier in the season than shrubs. A 15N tracer was added with the first rain event and plant samples were collected regularly to track the movement of N into the plants. Net soil N accumulation was determined using resin bags. Invasive grasses altered the timing and amount of N uptake but amount of rainfall had less effect on N distribution. 15N was detected sooner and at higher level in grasses than shrubs. 24hours after the first rain event 15N was detectable in grasses, 15N accumulated rapidly and peaked 2 months earlier than shrubs. Shrub 15N levels remained at pre-rain event levels for the first 2 months and began to increase at the beginning of spring, peak mid-spring and decline as the shrubs entered summer dormancy. One year later 15N levels in annual grass litter remained high, while 15N levels in shrubs returned to initial background levels as a result of resorption. 15N concentrations are more variable in grasses which could indicate higher plasticity in grass N uptake compared to shrubs. Resin N supports the 15N patterns. Resin N declined more rapidly under grasses and was lower than under shrubs, presumably due to high grass N uptake. Resin N was particularly high under shrubs in wetter conditions indicating that shrubs could not take advantage of high N supply. Together the 15N and resin N patterns indicate that grasses accumulate more N and begin N uptake earlier in the season than shrubs. Although 15N did not differ in response to rainfall, invasion alters the distribution of N in the system. Rain was only manipulated for one growing season; multiple years of altered precipitation may yield significant differences. Early season N uptake by grasses, the low variability in shrub 15N and low shrub 15N in wetter conditions, despite high resin N, indicates that N competition between invasive grasses and native shrubs is weak. If N supply is sufficient for shrub demands, invasive grasses and shrubs could coexist. This study contributes to a broader understanding of how changes in resource supply, plant phenology and functional type interact and respond to climate change.

76 FR 26927 - National Organic Program; Notice on the Ruminant Slaughter Stock Provision of the Access to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-10

... Received on Labeling and Grass-Fed Products Many commenters suggested that there is a place for both grass... labeling system: ``Organic--Grass Fed/Grain Finished,'' ``Organic--Grass Fed/Finished on Pasture with Supplemental Grain Feeding,'' ``Organic--100% Grass Fed/Grass Finished.'' Their recommendation suggested that...

Exotic Grass Yields Under Southern Pines

Treesearch

H.A. Pearson

1975-01-01

Kentucky 31 and Kenwell tall fescue, Pensacola bahia, and Brunswick grasses yielded nea,rly three times more forage under an established pine stand than native grasses 7 years after seeding. Introducing exotic grasses did not significantly increase total grass production but did enhance range quality since the cool-season grasses are green during winter and are higher...

Herbicide treatment effects on properties of mountain big sagebrush soils after fourteen years

NASA Technical Reports Server (NTRS)

Burke, I. C.; Reiners, W. A.; Sturges, D. L.; Matson, P. A.

1987-01-01

The effects of sagebrush conversion on the soil properties of a high-elevation portion of the Western Intermountain Sagebrush Steppe (West, 1983) are described. Changes were found in only a few soil chemical properties after conversion to grassland. It was found that surface concentrations of N were lower under grass vegetation than under undisturbed vegetation. Undershrub net N mineralization rates were higher under shrubs in the sagebrush vegetation than under former shrubs in the grass vegetation.

Heed the head: buffer benefits along headwater streams

Treesearch

Rhonda Mazza; Deanna (Dede) Olson

2015-01-01

Since the Northwest Forest Plan implemented riparian buffers along non-fish bearing streams in 1994, there have been questions about how wide those buffers need to be to protect aquatic and riparian resources from upland forest management activities. The Density Management and Riparian Buffer Study of western Oregon, also initiated in 1994, examines the effects of...

VAM populations in relation to grass invasion associated with forest decline.

PubMed

Vosatka, M; Cudlin, P; Mejstrik, V

1991-01-01

Spruce stands in Northern Bohemia forests, damaged to various degrees by industrial pollution, have shown establishment of grass cover following tree defoliation. Populations of vesicular-arbuscular mycorrhizal (VAM) fungi were studied under this grass cover in four permanent plots with spruce under different levels of pollution stress. Soil and root samples were collected in April and June within each plot as follows: (1) sites without grass, (2) sites with initial stages of grass invasion, and (3) sites with fully developed grass cover. In all plots, the highest number of propagules were recovered from samples taken from sites having full grass cover. Mycorrhizal infection of grass was highest in the plot with the severest pollution damage and lowest in the least damaged plot. The development of grass cover and VAM infection of grass increased with tree defoliation caused by air pollution.

On-farm feeding interventions to increase milk production in lactating dairy cows.

PubMed

Wanapat, Metha; Foiklang, Suban; Phesatcha, Kampanat; Paoinn, Chainarong; Ampapon, Thiwakorn; Norrapoke, Thitima; Kang, Sungchhang

2017-04-01

The objective of this study was to investigate the effect of tropical legume (Phaseolus calcaratus) mixed with ruzi grass feeding on the performance of lactating dairy cows. Eighty-eight lactating dairy cows from 22 smallholder dairy farms northeast of Thailand were assigned to respective dietary treatments according to a Randomized Completely Block Design (RCBD). Four cows were selected from each farm and were allocated into two different feeding groups as follows: ruzi grass and P. calcaratus mixed with ruzi grass (1:1 ratio), respectively. All cows were fed with roughage ad libitum with 1:2 ratio of concentrate diet to milk yield. The results revealed that total dry matter intake, ruminal volatile fatty acids, and ammonia nitrogen concentration were enhanced when cows were fed with P. calcaratus mixed with ruzi grass (P < 0.05). Moreover, feeding tropical legume mixed with ruzi grass could increase milk production and milk protein in this study. Importantly, an economical assessment showed that milk income and the profit from milk sale were significantly greater in cows fed the mixture of roughage than those from the non-mixed group. This study concluded that high-quality roughage as tropical legume mixed with ruzi grass at the ratio of 1:1 brought out the remarkable and practical implementation for smallholder dairy farms, and the intervention was practical and deserving of more on-farm intervention.

Feasibility of an implantable capsule for limiting lifespan of grass carp

USGS Publications Warehouse

Thomas, R.M.; Miranda, L.E.; Kirk, J.P.

2006-01-01

The grass carp (Ctenopharyngodon idella) is an herbivorous cyprinid stocked to control undesirable aquatic vegetation. However, stocking grass carp presents several problems including complete eradication of submersed aquatic vegetation, dispersal out of the target area, adverse effects on fish communities, and damage to waterfowl habitat and native vegetation. The purpose of this research was to consider the feasibility of an implantable capsule for limiting the lifespan of grass carp. Stainless steel dowel pins were inserted into 49 fish to identify the most appropriate site to implant the capsule. The throat region along the body's longitudinal axis was identified as the most suitable location because it resulted in minimal loss over an 8-month holding period. Rotenone solutions were injected into the ventral surface between the pelvic fins to determine the lethal dosage to 95% of the population (LD 95). The LD95 for grass carp increased curvilin-early with fish weight. Four polymers that merit further evaluation in constructing the capsule are poly[bis(p-carboxyphenoxy) propane anhydride], poly[bis(p- carboxyphenoxy) hexane anhydride], poly-1-lactide, and poly(??-caprolactone) . Implants are commonly used to deliver pharmaceutical products in medical and veterinarian applications, and have been used in fish. Developing a bioerodible capsule could increase the safety and flexibility of stocking grass carp for control of aquatic plants, and may also be applicable for management of other exotic species.

Microsatellite genetic diversity and differentiation of native and introduced grass carp populations in three continents

USGS Publications Warehouse

Chapman, Duane C.; Chen, Qin; Wang, Chenghui; Zhao, Jinlian; Lu, Guoqing; Zsigmond, Jeney; Li, Si-Fa

2012-01-01

Grass carp (Ctenopharyngodon idella), a freshwater species native to China, has been introduced to about 100 countries/regions and poses both biological and environmental challenges to the receiving ecosystems. In this study, we analyzed genetic variation in grass carp from three introduced river systems (Mississippi River Basin in US, Danube River in Hungary, and Tone River in Japan) as well as its native ranges (Yangtze, Pearl, and Amur Rivers) in China using 21 novel microsatellite loci. The allelic richness, observed heterozygosity, and within-population gene diversity were found to be lower in the introduced populations than in the native populations, presumably due to the small founder population size of the former. Significant genetic differentiation was found between all pairwise populations from different rivers. Both principal component analysis and Bayesian clustering analysis revealed obvious genetic distinction between the native and introduced populations. Interestingly, genetic bottlenecks were detected in the Hungarian and Japanese grass carp populations, but not in the North American population, suggesting that the Mississippi River Basin grass carp has experienced rapid population expansion with potential genetic diversification during the half-century since its introduction. Consequently, the combined forces of the founder effect, introduction history, and rapid population expansion help explaining the observed patterns of genetic diversity within and among both native and introduced populations of the grass carp.

Greenhouse studies on the phyto-extraction capacity of Cynodon nlemfuensis for lead and cadmium under irrigation with treated wastewater

NASA Astrophysics Data System (ADS)

Madyiwa, S.; Chimbari, M. J.; Schutte, C. F.; Nyamangara, J.

For over 30 years, discharge of sewage effluent and sludge on pasturelands has been used in Zimbabwe as a cheap method for secondary treatment of wastewater without any monitoring of accumulation of heavy metals in soils and grasses, let alone in animals grazing on the pastures. Cynodon nlemfuensis (star grass) has been the main grass planted on the wastewater irrigated pasturelands. This study was conducted to assess the capacity of star grass to accumulate lead (Pb) and cadmium (Cd) and develop models incorporating grass yield, metal uptake and soil bio-available (EDTA extractable) metal content, that could be used to determine critical grass and soil concentrations at which grass productivity declines. Star grass was planted in 30 fertilized pots containing sandy soil within a greenhouse. The pots consisted of nine treatments of varying levels of added inorganic Pb and Cd subjected to treated wastewater application and one control that had no added metals and received water application only. The elements were applied to the soils once just after planting the grass. Chemical analyses showed that star grass had a relatively high phyto-extraction capacity of Pb and Cd, comparable to that of hyper-accumulating grasses such as Lolium perenne (rye grass). It accumulated Pb and Cd to levels far beyond the recommended maximum limits for pasture grass. Analysis of variance on log-normal transformed data showed that bio-available soil metal concentrations correlated strongly with grass metal content and grass metal content correlated strongly with the yield. There was however a weak correlation between the yield and bio-available soil levels. The yield versus grass metal content models that were developed for the first crop and re-growth predicted similar critical metal concentrations and yields. Using the critical grass metal concentrations in the soil bio-available metal concentration versus grass metal concentration models allowed for the prediction of the corresponding critical soil concentrations.

Use of eyeballs for establishing ploidy of Asian carp

USGS Publications Warehouse

Jenkins, J.A.; Thomas, R.G.

2007-01-01

Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve black carp Mylopharyngodon piceus were recently captured from the Mississippi and Atchafalaya River system, and 10 were analyzed for ploidy. By using the methods described herein, all 10 fish were determined to be diploid. Such correct identifications of ploidy of feral Asian carp species, as well as other species, would provide science-based information constructive for meeting reporting requirements, tracking fish movements, and forecasting expansion of species distribution. To investigate the postmortem period for sample collection and to lessen demands on field operations for obtaining samples, a laboratory study was performed to determine the length of time for which eyeballs from postmortem black carp could be used for ploidy determinations. Acquiring eyes rather than blood is simpler and quicker and requires no special supplies. An internal DNA reference standard with a documented genome size, including erythrocytes from diploid black carp or Nile tilapia Oreochromis niloticus, was analyzed simultaneously with cells from seven known triploid black carp to assess ploidy through 12 d after extraction. Ploidy determinations were reliable through 8 d postmortem. The field process entails excision of an eyeball, storage in a physiological buffer, and shipment within 8 d at refrigeration temperatures (4??C) to the laboratory for analysis by flow cytometry. ?? Copyright by the American Fisheries Society 2007.

ECOSYS-87: Model calculations of the activity in cattle meat related to deposition time and feeding regimes after a nuclear fallout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riesen, T.K.; Gottofrey, J.; Heiz, H.J.

1996-12-01

The radioecological model ECOSYS087 was used to evaluate the effect of countermeasures for reducing the ingestion dose by eating cattle meat after an accidental release of radioactive material. Calculations were performed using a database adapted to Swiss conditions for the case that (1) contaminated grass or hay is replaced by clean fodder; (2) the last 100 days before slaughter, taking place one year after an accident, only uncontaminated fodder is given; and (3) alternative feeding regimes are chosen. Seasonal effects were considered by doing all calculations for a deposition at each month of the year. Feeding uncontaminated forage 100 dmore » before slaughter (case 2) proved to be the most effective countermeasure and reduced the integrated activity in meat by 90% to 99%. The effect of replacing contaminated grass (case 1) was less uniform and depended strongly on the time a deposition occurred. In this case the reduction was between 50% and 100% one year after deposition. The substitution of contaminated hay (case 1) was less effective compared to the substitution of grass. The choice of alternative feeding regimes (case 1) was less effective compared to the substitution of grass. The choice of alternative feeding regimes (case 3) led to a reduction of the integrated activity of up to 40% one year after deposition. The present model calculations clearly reveal the importance of the seasonality and demonstrate the usefulness of such calculations as a basis for generating countermeasures in decision support systems. 8 refs., 1 fig., 5 tabs.« less

Modified batch anaerobic digestion assay for testing efficiencies of trace metal additives to enhance methane production of energy crops.

PubMed

Brulé, Mathieu; Bolduan, Rainer; Seidelt, Stephan; Schlagermann, Pascal; Bott, Armin

2013-01-01

Batch biochemical methane potential (BMP) assays to evaluate the methane yield of biogas substrates such as energy crops are usually carried out with undiluted inoculum. A BMP assay was performed on two energy crops (green cuttings and grass silage). Anaerobic digestion was performed both with and without supplementation of three commercial additives containing trace metals in liquid, solid or adsorbed form (on clay particles). In order to reveal positive effects of trace metal supplementation on the methane yield, besides undiluted inoculum, 3-fold and 10-fold dilutions of the inoculum were applied for substrate digestion. Diluted inoculum variants were supplemented with both mineral nutrients and pH-buffering substances to prevent a collapse of the digestion process. As expected, commercial additives had no effect on the digestion process performed with undiluted inoculum, while significant increases of methane production through trace element supplementation could be observed on the diluted variants. The effect of inoculum dilution may be twofold: (1) decrease in trace metal supplementation from the inoculum and (2) reduction in the initial number of bacterial cells. Bacteria require higher growth rates for substrate degradation and hence have higher trace element consumption. According to common knowledge of the biogas process, periods with volatile fatty acids accumulation and decreased pH may have occurred in the course ofanaerobic digestion. These effects may have led to inhibition, not only ofmethanogenes and acetogenes involved in the final phases of methane production, but also offibre-degrading bacterial strains involved in polymer hydrolysis. Further research is required to confirm this hypothesis.

Modeling framework for representing long-term effectiveness of best management practices in addressing hydrology and water quality problems: Framework development and demonstration using a Bayesian method

NASA Astrophysics Data System (ADS)

Liu, Yaoze; Engel, Bernard A.; Flanagan, Dennis C.; Gitau, Margaret W.; McMillan, Sara K.; Chaubey, Indrajeet; Singh, Shweta

2018-05-01

Best management practices (BMPs) are popular approaches used to improve hydrology and water quality. Uncertainties in BMP effectiveness over time may result in overestimating long-term efficiency in watershed planning strategies. To represent varying long-term BMP effectiveness in hydrologic/water quality models, a high level and forward-looking modeling framework was developed. The components in the framework consist of establishment period efficiency, starting efficiency, efficiency for each storm event, efficiency between maintenance, and efficiency over the life cycle. Combined, they represent long-term efficiency for a specific type of practice and specific environmental concern (runoff/pollutant). An approach for possible implementation of the framework was discussed. The long-term impacts of grass buffer strips (agricultural BMP) and bioretention systems (urban BMP) in reducing total phosphorus were simulated to demonstrate the framework. Data gaps were captured in estimating the long-term performance of the BMPs. A Bayesian method was used to match the simulated distribution of long-term BMP efficiencies with the observed distribution with the assumption that the observed data represented long-term BMP efficiencies. The simulated distribution matched the observed distribution well with only small total predictive uncertainties. With additional data, the same method can be used to further improve the simulation results. The modeling framework and results of this study, which can be adopted in hydrologic/water quality models to better represent long-term BMP effectiveness, can help improve decision support systems for creating long-term stormwater management strategies for watershed management projects.

C₃ and C₄ plant responses to increased temperatures and altered monsoonal precipitation in a cool desert on the Colorado Plateau, USA.

PubMed

Wertin, Timothy M; Reed, Sasha C; Belnap, Jayne

2015-04-01

Dryland ecosystems represent >40% of the terrestrial landscape and support over two billion people; consequently, it is vital to understand how drylands will respond to climatic change. However, while arid and semiarid ecosystems commonly experience extremely hot and dry conditions, our understanding of how further temperature increases or altered precipitation will affect dryland plant communities remains poor. To address this question, we assessed plant physiology and growth at a long-term (7-year) climate experiment on the Colorado Plateau, USA, where the community is a mix of shallow-rooted C3 and C4 grasses and deep-rooted C4 shrubs. The experiment maintained elevated-temperature treatments (+2 or +4 °C) in combination with altered summer monsoonal precipitation (+small frequent precipitation events or +large infrequent events). Increased temperature negatively affected photosynthesis and growth of the C3 and C4 grasses, but effects varied in their timing: +4 °C treatments negatively affected the C3 grass early in the growing season of both years, while the negative effects of temperature on the C4 grass were seen in the +2 and +4 °C treatments, but only during the late growing season of the drier year. Increased summer precipitation did not affect photosynthesis or biomass for any species, either in the year the precipitation was applied or the following year. Although previous research suggests dryland plants, and C4 grasses in particular, may respond positively to elevated temperature, our findings from a cool desert show marked declines in C3 and C4 photosynthesis and growth, with temperature effects dependent on the degree of warming and growing-season precipitation.

C3 and C4 plant responses to increased temperatures and altered monsoonal precipitation in a cool desert on the Colorado Plateau, USA

USGS Publications Warehouse

Wertin, Timothy M.; Reed, Sasha C.; Belnap, Jayne

2015-01-01

Dryland ecosystems represent >40 % of the terrestrial landscape and support over two billion people; consequently, it is vital to understand how drylands will respond to climatic change. However, while arid and semiarid ecosystems commonly experience extremely hot and dry conditions, our understanding of how further temperature increases or altered precipitation will affect dryland plant communities remains poor. To address this question, we assessed plant physiology and growth at a long-term (7-year) climate experiment on the Colorado Plateau, USA, where the community is a mix of shallow-rooted C3 and C4 grasses and deep-rooted C4 shrubs. The experiment maintained elevated-temperature treatments (+2 or +4 °C) in combination with altered summer monsoonal precipitation (+small frequent precipitation events or +large infrequent events). Increased temperature negatively affected photosynthesis and growth of the C3 and C4 grasses, but effects varied in their timing: +4 °C treatments negatively affected the C3 grass early in the growing season of both years, while the negative effects of temperature on the C4 grass were seen in the +2 and +4 °C treatments, but only during the late growing season of the drier year. Increased summer precipitation did not affect photosynthesis or biomass for any species, either in the year the precipitation was applied or the following year. Although previous research suggests dryland plants, and C4 grasses in particular, may respond positively to elevated temperature, our findings from a cool desert show marked declines in C3 and C4 photosynthesis and growth, with temperature effects dependent on the degree of warming and growing-season precipitation.

Equipment and strategies to enhance the post-wildfire establishment and persistence of Great Basin native plants

Treesearch

Nancy Shaw; Beth Newingham; Amy C. Ganguli; Ann L. Hild; Robert D. Cox; Jim Truax; Mike Pellant; David Pyke; Dan Ogle

2011-01-01

Annual grass invasion in the Great Basin has increased fire size, frequency and severity. Post-fire restoration to provide functional native plant communities is critical to improve resistance to weed invasion. Our ability to successfully re-establish mixtures of native grasses, forbs and shrubs, however, is limited. We examined the effects of the standard rangeland...

Effects of post-fire grass seeding on native vegetation in southern California chaparral

Treesearch

Jan L. Beyers; Carla D. Wakeman; Peter M. Wohlgemuth; Susan G. Conard

1998-01-01

For decades, managers have seeded burned slopes with annual grass in an attempt to increase postfire plant cover and reduce the accelerated hillslope erosion, runoff, and debris flows that typically occur during the first winter after fire. In California, annual ryegrass (Lolium multiflorum) was commonly used for this purpose. Critics argue that ryegrass and other...

Physiological and Morphological Effects of High Water Tables on Early Growth of Giant Reed (Arundo donax), Elephant Grass (Pennisetum purpureum), Energycane and Sugarcane (Saccharum spp.)

USDA-ARS?s Scientific Manuscript database

Increasing demand for renewable energy sources has led to interest in high-biomass crops. Species that have been proposed as well-suited for biofuel production in the Everglades Agricultural Area (EAA) of Florida include Giant Reed (Arundo donax), Elephant Grass (Pennisetum purpureum), Energycane (S...

Per capita community-level effects of an invasive grass, Microstegium vimineum, on vegetation in mesic forests in northern Mississippi (USA)

Treesearch

J. Stephen Brewer

2010-01-01

Quantifying per capita impacts of invasive species on resident communities requires integrating regression analyses with experiments under natural conditions. Using multivariate and univariate approaches, I regressed the abundance of 105 resident species of groundcover plants and tree seedlings against the abundance and height of an invasive grass, Microstegium...

Effect of an Invasive Grass on Ambient Rates of Decomposition and Microbial Community Structure: A Search for Causality

USDA-ARS?s Scientific Manuscript database

In sutu decomposition of above and below ground plant biomass of the native grass species Andropogon glmoeratus (Walt.) B.S.P and exotic Imperata cylindrica (L.) Beauv. (cogongrass) was investigated using litter bags over the course of a 12 month period. The above and below ground biomass of the inv...

26 CFR 1.6033-2 - Returns by exempt organizations (taxable years beginning after December 31, 1969) and returns by...

Code of Federal Regulations, 2011 CFR

2011-04-01

... for the performance of such services. (h) A schedule showing the compensation and other payments made... expenditures, grass roots expenditures, exempt purpose expenditures, lobbying nontaxable amount, and grass... meaning of § 1.501(h)-3(c)(7)), if the organization has an election under section 501(h) in effect for the...

The effects of fire events on soil geochemistry in semi-arid grasslands

Treesearch

Thomas H. Biggs; Lisa N. Florkowski; Philip A. Pearthree; Pei-Jen L. Shaner

2005-01-01

Throughout the southwestern United States, vegetation in what historically was grassland has changed to a mixture of trees and shrubs; exotic grass species and undesirable shrubs have also invaded the grasslands at the expense of native grasses. The availability and amount of soil nutrients influence the relative success of plants, but few studies have examined fire...

Effect on Grass and Cereal Seedlings of Hydrogen Cyanide Produced by Mycelium and Sporophores of Marasmius oreades

Treesearch

T. H. Filer

1966-01-01

Hydrogen cyanide caused root damage to Poa pratensis, Festuca rubra, and Agrostis tenuis when the grasses were suspended 7 days above a 28-day-old viable culture Marasmius oreades (Bolt. ) Fr. The amount of HCN produced by this culture (Washington isolate 1) averaged 49 ppm per 24 hours collected in 5 ml of...

Native species regeneration following ungulate exclusion and nonnative grass removal in a remnant Hawaiian dry forest

Treesearch

Jarrod M. Thaxton; T. Colleen Cole; Susan Cordell; Robert J. Cabin; Darren R. Sandquist; Creighton M. Litton

2010-01-01

Hawaiian lowland dry forests have been reduced by >90% since first human contact. Restoration has focused on protection from fire and ungulates, and removal of invasive grasses as ways to stimulate native forest regeneration. Despite these efforts, natural regeneration of native plants has been infrequent. To assess effects of previous restoration treatments on...

Growth projection and valuation of restoration of the shortleaf pine-bluestem grass ecosystem

Treesearch

Difei Zhang; Michael M. Huebschmann; Thomas B. Lynch; James M. Guldin

2012-01-01

The fire-dependent shortleaf pine–bluestem grass ecosystem that existed prior to European settlement is being restored on approximately 62,700 ha in the Ouachita National Forest. The restoration effort's economic effects are not completely understood. This study will provide the Forest Service with a framework for better communicating the biological and economic...

Evaluating the effects of buffer conditions and extremolytes on thermostability of granulocyte colony-stimulating factor using high-throughput screening combined with design of experiments.

PubMed

Ablinger, Elisabeth; Hellweger, Monika; Leitgeb, Stefan; Zimmer, Andreas

2012-10-15

In this study, we combined a high-throughput screening method, differential scanning fluorimetry (DSF), with design of experiments (DoE) methodology to evaluate the effects of several formulation components on the thermostability of granulocyte colony stimulating factor (G-CSF). First we performed a primary buffer screening where we tested thermal stability of G-CSF in different buffers, pH values and buffer concentrations. The significance of each factor and the two-way interactions between them were studied by multivariable regression analysis. pH was identified as most critical factor regarding thermal stability. The most stabilizing buffer, sodium glutamate, and sodium acetate were determined for further investigations. Second we tested the effect of 6 naturally occurring extremolytes (trehalose, sucrose, ectoine, hydroxyectoine, sorbitol, mannitol) on the thermal stability of G-CSF, using a central composite circumscribed design. At low pH (3.8) and low buffer concentration (5 mM) all extremolytes led to a significant increase in thermal stability except the addition of ectoine which resulted in a strong destabilization of G-CSF. Increasing pH and buffer concentration led to an increase in thermal stability with all investigated extremolytes. The described systematic approach allowed to create a ranking of stabilizing extremolytes at different buffer conditions. Copyright © 2012. Published by Elsevier B.V.

Hydrochemical buffer assessment in agricultural landscapes: from local to catchment scale.

PubMed

Viaud, Valérie; Merot, Philippe; Baudry, Jacques

2004-10-01

Non-point-source pollution of surface and groundwater is a prominent environmental issue in rural catchments, with major consequences on water supply and aquatic ecosystem quality. Among surface-water protection measures, environmental or landscape management policies support the implementation and the management of buffer zones. Although a great number of studies have focused on buffer zones, quantification of the buffer effect is still a recurring question. The purpose of this article is a critical review of the assessment of buffer-zone functioning. Our objective is to provide land planners and managers with a set of variables to assess the limits and possibilities for quantifying buffer impact at the catchment scale. We first consider the scale of the local landscape feature. The most commonly used empirical method for assessing buffers is to calculate water/nutrient budgets from inflow-outflow monitoring at the level of landscape structures. We show that several other parameters apart from mean depletion of flux can be used to describe buffer functions. Such parameters include variability, with major implication for water management. We develop a theoretical framework to clarify the assessment of the buffer effect and propose a systematic analysis taking account of temporal variability. Second, we review the current assessment of buffer effects at the catchment scale according to the theoretical framework established at the local scale. Finally, we stress the limits of direct empirical assessment at the catchment scale and, in particular, we emphasize the hierarchy in hydrological processes involved at the catchment scale: The landscape feature function is constrained by other factors (climate and geology) that are of importance at a broader spatial and temporal scale.

A comparison of alternative strategies for cost-effective water quality management in lakes.

PubMed

Kramer, Daniel Boyd; Polasky, Stephen; Starfield, Anthony; Palik, Brian; Westphal, Lynne; Snyder, Stephanie; Jakes, Pamela; Hudson, Rachel; Gustafson, Eric

2006-09-01

Roughly 45% of the assessed lakes in the United States are impaired for one or more reasons. Eutrophication due to excess phosphorus loading is common in many impaired lakes. Various strategies are available to lake residents for addressing declining lake water quality, including septic system upgrades and establishing riparian buffers. This study examines 25 lakes to determine whether septic upgrades or riparian buffers are a more cost-effective strategy to meet a phosphorus reduction target. We find that riparian buffers are the more cost-effective strategy in every case but one. Large transaction costs associated with the negotiation and monitoring of riparian buffers, however, may be prohibiting lake residents from implementing the most cost-effective strategy.

A Comparison of Alternative Strategies for Cost-Effective Water Quality Management in Lakes

NASA Astrophysics Data System (ADS)

Kramer, Daniel Boyd; Polasky, Stephen; Starfield, Anthony; Palik, Brian; Westphal, Lynne; Snyder, Stephanie; Jakes, Pamela; Hudson, Rachel; Gustafson, Eric

2006-09-01

Roughly 45% of the assessed lakes in the United States are impaired for one or more reasons. Eutrophication due to excess phosphorus loading is common in many impaired lakes. Various strategies are available to lake residents for addressing declining lake water quality, including septic system upgrades and establishing riparian buffers. This study examines 25 lakes to determine whether septic upgrades or riparian buffers are a more cost-effective strategy to meet a phosphorus reduction target. We find that riparian buffers are the more cost-effective strategy in every case but one. Large transaction costs associated with the negotiation and monitoring of riparian buffers, however, may be prohibiting lake residents from implementing the most cost-effective strategy.

Effects of Fixatives and Buffers upon the Morphology of Heart and Skeletal Muscle Mitochondria from Exhausted Rats.

ERIC Educational Resources Information Center

Gale, James B.

This study describes the effects of several fixatives and buffers on the morphology of mitochondria from resting and exhausted rats. Rats were run to exhaustion and adjacent portions from the left ventricle or from the soleus were treated with the following fixation procedures: (a) glutaraldehyde buffered with cacodylate, S-collidine, or phosphate…

Bacterial rhizosphere and endosphere populations associated with grasses and trees to be used for phytoremediation of crude oil contaminated soil.

PubMed

Fatima, Kaneez; Afzal, Muhammad; Imran, Asma; Khan, Qaiser M

2015-03-01

Different grasses and trees were tested for their growth in a crude oil contaminated soil. Three grasses, Lolium perenne, Leptochloa fusca, Brachiaria mutica, and two trees, Lecucaena leucocephala and Acacia ampliceps, were selected to investigate the diversity of hydrocarbon-degrading rhizospheric and endophytic bacteria. We found a higher number of hydrocarbon degrading bacteria associated with grasses than trees and that the endophytic bacteria were taxonomically different from rhizosphere associated bacteria showing their spatial distribution with reference to plant compartment as well as genotype. The rhizospheric soil yielded 22 (59.45 %), root interior yielded 9 (24.32 %) and shoot interior yielded 6 (16.21 %) hydrocarbon-degrading bacteria. These bacteria possessed genes encoding alkane hydroxylase and showed multiple plant growth-promoting activities. Bacillus (48.64 %) and Acinetobacter (18.91 %) were dominant genera found in this study. At 2 % crude oil concentration, all bacterial isolates exhibited 25 %-78 % oil degradation and Acinetobacter sp. strain BRSI56 degraded maximum. Our study suggests that for practical application, support of potential bacteria combined with the grasses is more effective approach than trees to remediate oil contaminated soils.

Molecular detection of genotype II grass carp reovirus based on nucleic acid sequence-based amplification combined with enzyme-linked immunosorbent assay (NASBA-ELISA).

PubMed

Zeng, Weiwei; Yao, Wei; Wang, Yingying; Li, Yingying; Bermann, Sven M; Ren, Yan; Shi, Cunbin; Song, Xinjian; Huang, Qiwen; Zheng, Shuchen; Wang, Qing

2017-05-01

Grass carp reovirus (GCRV) is the causative agent of the grass carp hemorrhagic disease that has resulted in severe economic losses in the grass carp (Ctenopharyngodon idella) farming industry in China. Early diagnosis and vaccine administration are important priorities for GCRV control. In this study, a nucleic acid sequence-based amplification with enzyme-linked immunosorbent assay (NASBA-ELISA) was developed for to detect genotype II GCRV (GCRV- II). Primers specifically targeting viral RNA genome segment 6 were utilized for amplification in an isothermal digoxigenin-labeling NASBA process, resulting in DIG-labeled RNA amplicons. The amplicons were hybridized to specific biotinylated DNA probes and the products were detected colorimetrically using horseradish peroxidase and a microplate reader. The new method is able to detect GCRV at 14 copies/μL within 5h and had a diagnostic sensitivity and a specificity of 100% when GCRV-II and non-target virus were tested. This NASBA-ELISA was evaluated using a panel of clinical samples (n=103) to demonstrate that it is a rapid, effective and sensitive method for GCRV detection in grass carp aquaculture. Copyright © 2017 Elsevier B.V. All rights reserved.

An African grassland responds similarly to long-term fertilization to the Park Grass experiment.

PubMed

Ward, David; Kirkman, Kevin; Tsvuura, Zivanai

2017-01-01

We compared the results of a long-term (65 years) experiment in a South African grassland with the world's longest-running ecological experiment, the Park Grass study at Rothamsted, U.K. The climate is warm and humid in South Africa and cool and temperate in England. The African grassland has been fertilized with two forms of nitrogen applied at four levels, phosphorus and lime in a crossed design in 96 plots. In 1951, about 84% of plant cover consisted of Themeda triandra, Tristachya leucothrix and Setaria nigrirostris. Currently, the dominant species are Panicum maximum, Setaria sphacelata and Eragrostis curvula, making up 71% of total biomass. As in the Park Grass experiment, we found a significant (additive) interaction effect on ANPP of nitrogen and phosphorus, and a (marginally significant) negative correlation between ANPP and species richness. Unlike the Park Grass experiment, there was no correlation between ANPP and species richness when pH was included as a covariate. There was also a significant negative effect of nitrogen amount and nitrogen form and a positive effect of lime on species richness and species diversity. Soil pH had an important effect on species richness. Liming was insufficient to balance the negative effects on species richness of nitrogen fertilization. There was a significant effect of pH on biomass of three abundant species. There were also significant effects of light on the biomass of four species, with only Panicum maximum having a negative response to light. In all of the abundant species, adding total species richness and ANPP to the model increased the amount of variance explained. The biomass of Eragrostis curvula and P. maximum were negatively correlated with species richness while three other abundant species increased with species richness, suggesting that competition and facilitation were active. Consistent with the results from the Park Grass and other long-term fertilization experiments of grasslands, we found a positive effect of soil pH and a negative effect of nitrogen amount on species richness, a more acutely negative effect on species richness of acidic ammonium sulphate fertilizer than limestone ammonium nitrate, a negative relationship between species richness and biomass, and a positive effect on species richness of lime interacting with nitrogen.

Effect of pH buffering capacity and sources of dietary sulfur on rumen fermentation, sulfide production, methane production, sulfate reducing bacteria, and total Archaea in in vitro rumen cultures.

PubMed

Wu, Hao; Meng, Qingxiang; Yu, Zhongtang

2015-06-01

The effects of three types of dietary sulfur on in vitro fermentation characteristics, sulfide production, methane production, and microbial populations at two different buffer capacities were examined using in vitro rumen cultures. Addition of dry distilled grain with soluble (DDGS) generally decreased total gas production, degradation of dry matter and neutral detergent fiber, and concentration of total volatile fatty acids, while increasing ammonia concentration. High buffering capacity alleviated these adverse effects on fermentation. Increased sulfur content resulted in decreased methane emission, but total Archaea population was not changed significantly. The population of sulfate reducing bacteria was increased in a sulfur type-dependent manner. These results suggest that types of dietary sulfur and buffering capacity can affect rumen fermentation and sulfide production. Diet buffering capacity, and probably alkalinity, may be increased to alleviate some of the adverse effects associated with feeding DDGS at high levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study on the reduction and hysteresis effect of soil nitrogen pollution by Alfalfa in channel buffer bank

NASA Astrophysics Data System (ADS)

Chi, Yixia; Xue, Lianqing; Zhang, Zhanyu; Li, Dongying

2018-01-01

Based on the simulation experiments of solute transport in channel buffer bank and pot experiments, this study analyzed the transport of nitrogen pollution from farmland drains along the South-North Water Transfer east route project; and compared the nitrogen transport rule and purification effect of alfalfa in channel buffer bank soil under situations of bare land and alfalfa mulching. The results showed that: (1) soil nitrogen content decreased gradually with the width increase of channel buffer bank by the soil adsorption and decomposition; (2) the migration rates of nitrogen were 0.06 g·kg-1 by the alfalfa mulching; (3) the removed rates of nitrogen from the soil were 0.088 g·kg-1 by cutting alfalfa; (4) the residual nitrogen of soil with alfalfa was 10% of the bare land. Alfalfa in channel buffer bank had obvious reduction and hysteresis effect to soil nitrogen pollution.

Grass fungal endophytes and uses thereof

DOEpatents

Craven, Kelly

2015-03-10

The invention provides isolated fungal endophytes and synthetic combinations thereof with host grass plants. Methods for inoculating grass plant with the endophytes, for propagating the grass-endophyte combinations, and for producing feeds and biofuels from grass-endophyte combinations are also provided.

Effects of vegetation on runoff generation, sediment yield and soil shear strength on road-side slopes under a simulation rainfall test in the Three Gorges Reservoir Area, China.

PubMed

Liu, Yao-Jun; Wang, Tian-Wei; Cai, Chong-Fa; Li, Zhao-Xia; Cheng, Dong-Bing

2014-07-01

Vegetation recolonization has often been used to control roadside slope erosion, and in this paper, four restoration models - Natural Restoration, Grass, Grass & Shrub, Sodded Strip - were chosen to recolonize the plants on a newly built unpaved roadside slope in the Three Gorges Reservoir Area. After eight months growth, eight rainfall simulations (intensity of 90 mm h(-1) for 60 min) and in-situ soil shear strength test were then carried out to identify the impacts of vegetation on roadside slope erosion and soil shear strength. The erosion on cutslopes was higher than that on fillslopes. The runoff coefficient and soil detachment rate were significantly lower on the Grass & Shrub model (4.3% and 1.99 g m(-2) min(-1), respectively) compared with the other three, which had the highest surface cover (91.4%), aboveground biomass (1.44 kg m(-2)) and root weight density (3.94 kg m(-3)). The runoff coefficient and soil detachment rate on roadside slopes showed a logarithmic decrease with the root weight density, root length density and aboveground biomass. The soil shear strength measured before and after the rainfall was higher on Grass & Shrub (59.29 and 53.73 kPa) and decreased on Grass (46.93 and 40.48 kPa), Sodded Strip (31.20 and 18.87 kPa) and Natural Restoration (25.31 and 9.36 kPa). Negative linear correlations were found between the soil shear strength reduction and aboveground biomass, root weight density and root length density. The variation of soil shear strength reduction was closely related to the roadside slope erosion, a positive linear correlation was found between runoff coefficient and soil shear strength reduction, and a power function was shown between soil detachment rate and soil shear strength reduction. This study demonstrated that Grass and Grass & Shrub were more suitable and highly cost-effective in controlling initial period erosion of newly built low-volume unpaved road. Copyright © 2014 Elsevier B.V. All rights reserved.

Alternative pathways to landscape transformation: Invasive grasses, burn severity and fire frequency in arid ecosystems

USGS Publications Warehouse

Klinger, Robert C.; Brooks, Matthew L.

2017-01-01

Arid ecosystems are often vulnerable to transformation to invasive-dominated states following fire, but data on persistence of these states are sparse. The grass/fire cycle is a feedback process between invasive annual grasses and fire frequency that often leads to the formation of alternative vegetation states dominated by the invasive grasses. However, other components of fire regimes, such as burn severity, also have the potential to produce long-term vegetation transformations. Our goal was to evaluate the influence of both fire frequency and burn severity on the transformation of woody-dominated communities to communities dominated by invasive grasses in major elevation zones of the Mojave Desert of western North America.We used a chronosequence design to collect data on herbaceous and woody cover at 229 unburned reference plots and 578 plots that burned between 1972 and 2010. We stratified the plots by elevation zone (low, mid, high), fire frequency (1–3 times) and years post-fire (YPF; 1–5, 6–10, 11–20 and 21–40 YPF). Burn severity for each plot was estimated by the difference normalized burn ratio.We identified two broad post-fire successional pathways. One was an outcome of fire frequency, resulting in a strong potential transformation via the grass/fire cycle. The second pathway was driven by burn severity, the critical aspect being that long-term transformation of a community could occur from just one fire in areas that burned at high or sometimes moderate severity. Dominance by invasive grasses was most likely to occur in low-and high-elevation communities; cover of native herbaceous species was often greater than that of invasive grasses in the mid-elevation zone.Synthesis. Invasive grasses can dominate a site that burned only one time in many decades at high severity, or a site that burned at low severity but multiple times in the same time period. However, high burn severity may predispose areas to more frequent fire because they have relatively high cover of invasive annual grass, suggesting burn severity and fire frequency have both independent and synergistic effects. Resilience in vegetation structure following fire in many arid communities may be limited to a narrow window of low burn severity in areas that have not burned in many decades.

Prediction of enteric methane emissions from sheep offered fresh perennial ryegrass () using data measured in indirect open-circuit respiration chambers.

PubMed

Zhao, Y G; O'Connell, N E; Yan, T

2016-06-01

Development of effective methane (CH) mitigation strategies for grazing sheep requires accurate prediction tools. The present study aimed to identify key parameters influencing enteric CH emissions and develop prediction equations for enteric CH emissions from sheep offered fresh grass. The data used were collected from 82 sheep offered fresh perennial ryegrass () as sole diets in 6 metabolism experiments (data from non-grass-only diets were not used). Sheep were from breeds of Highlander, Texel, Scottish Blackface, and Swaledale at the age of 5 to 18 mo and weighing from 24.5 to 62.7 kg. Grass was harvested daily from 6 swards on contrasting harvest dates (May to December). Before the commencement of each study, the experimental sward was harvested at a residual height of 4 cm and allowed to grow for 2 to 4 wk. The feeding trials commenced when the grass sward was suitable to zero grazing (average grass height = 15 cm), thus offering grass of a quality similar to what grazing animals would receive under routine grazing management. Sheep were housed in individual pens for 14 d and then moved to individual calorimeter chambers for 4 d. Feed intake, fecal and urine outputs, and CH emissions were measured during the final 4 d. Data were analyzed using the REML procedure to develop prediction equations for CH emissions. Linear and multiple prediction equations were developed using BW, DMI, GE intake (GEI), and grass chemical concentrations (DM, OM, water-soluble carbohydrates [WSC], NDF, ADF, nitrogen [N], GE, DE, and ME) as explanatory variables. The mean CH production was 21.1 g/kg DMI or 0.062 MJ/MJ GEI. Dry matter intake and GEI were much more accurate predictors for CH emissions than BW ( < 0.001, = 0.86 and = 0.87 vs. = 0.09, respectively). Adding grass DE and ME concentrations and grass nutrient concentrations (e.g., OM, N, GE, NDF, and WSC) to the relationships between DMI or GEI and CH emissions improved prediction accuracy with values increased to 0.93. Models based on farm-level data, for example, BW and grass nutrient (i.e., DM, GE, OM, and N) concentrations, were also developed and performed satisfactorily ( < 0.001, = 0.63). These models can contribute to improve prediction accuracy for enteric CH emissions from sheep grazing on ryegrass pasture.

Influence of grass pellet production on pyrrolizidine alkaloids occurring in Senecio aquaticus-infested grassland.

PubMed

Gottschalk, Christoph; Ostertag, Johannes; Meyer, Karsten; Gehring, Klaus; Thyssen, Stefan; Gareis, Manfred

2018-04-01

1,2-Dehydro-pyrrolizidine alkaloids (PA) and their N-oxides (PANO) exhibit acute and chronic toxic effects on the liver and other organs and therefore are a hazard for animal and human health. In certain regions of Germany, an increasing spread of Senecio spp. (ragwort) on grassland and farmland areas has been observed during the last years leading to a PA/PANO-contamination of feed and food of animal and plant origin. This project was carried out to elucidate whether the process of grass pellet production applying hot air drying influences the content of PA and PANO. Samples of hay (n = 22) and grass pellets (n = 28) originated from naturally infested grassland (around 10% and 30% dominance of Senecio aquaticus) and from a trial plot with around 50% dominance. Grass pellets were prepared from grass originating from exactly the same plots as the hay samples. The samples were analysed by liquid chromatography-tandem mass spectrometry for PA/PANO typically produced by this weed. The results of the study revealed that PA/PANO levels (predominantly sum of senecionine, seneciphylline, erucifoline and their N-oxides) in hay ranged between 2.1 and 12.6 mg kg -1 dry matter in samples with 10% and 30% dominance of S. aquaticus, respectively. Samples from the trial plot (50% dominance) had levels of up to 52.9 mg kg -1 . Notably, the hot air drying process during the production of grass pellets did not lead to a reduction of PA/PANO levels. Instead, the levels in grass pellets with 10% and 30% S. aquaticus ranged from 3.1 to 55.1 mg kg -1 . Grass pellets from the trial plot contained up to 96.8 mg kg -1 . In conclusion, hot air drying and grass pellet production did not affect PA/PANO contents in plant material and therefore, heat-dried products cannot be regarded as safe in view of the toxic potential of 1,2-dehydro-pyrrolizidine alkaloids.

Temporal variability in the life history and reproductive biology of female dugongs in Torres Strait: The likely role of sea grass dieback

NASA Astrophysics Data System (ADS)

Marsh, Helene; Kwan, Donna

2008-09-01

The extensive sea grass meadows in Torres Strait enable it to be a globally important habitat for the dugong, Dugong dugon, a marine mammal of cultural and dietary significance to Torres Strait Islanders and the basis for the substantial island-based fishery in the Torres Strait Protected Zone. Torres Strait sea grass communities are subjected to episodic diebacks which are now believed to be largely natural events. Information on dugong life history was obtained from specimens obtained from female dugongs as they were butchered for food by Indigenous hunters at two major dugong hunting communities in Torres Strait: Daru (9.04°S, 143.21°E) in 1978-1982 (a time of sea grass dieback and recovery) and Mabuiag Island (9.95°S, 142.15°E) in 1997-1999 (when sea grasses were abundant). Dugongs sampled in 1997-1999 had their first calf at younger ages (minimum of 6 cf. 10 years), and more frequently (interbirth interval based on all possible pregnancies 2.6±0.4 (S.E.) yr cf. 5.8±1.0 yr) than the dugongs sampled in 1978-1982. Pregnancy rates increased monotonically during 1978-1982, coincident with sea grass recovery. The age distribution of the female dugongs collected in 1997-1999 also suggested a low birth rate between 1973 and 1983 and/or or a high level of mortality for animals born during this period. These results add to the evidence from other regions that the life history and reproductive rate of female dugongs are adversely affected by sea grass loss, the effect of which cannot be separated from a possible density-dependent response to changes in dugong population size. Many green turtles in Torres Strait were also in poor body condition coincident with the 1970s sea grass dieback. The impacts of future sea grass diebacks need to be anticipated when management options for the traditional Torres Strait fisheries for dugongs and green turtles are evaluated.

Adverse postresuscitation myocardial effects elicited by buffer-induced alkalemia ameliorated by NHE-1 inhibition in a rat model of ventricular fibrillation.

PubMed

Lamoureux, Lorissa; Radhakrishnan, Jeejabai; Mason, Thomas G; Kraut, Jeffrey A; Gazmuri, Raúl J

2016-11-01

Major myocardial abnormalities occur during cardiac arrest and resuscitation including intracellular acidosis-partly caused by CO 2 accumulation-and activation of the Na + -H + exchanger isoform-1 (NHE-1). We hypothesized that a favorable interaction may result from NHE-1 inhibition during cardiac resuscitation followed by administration of a CO 2 -consuming buffer upon return of spontaneous circulation (ROSC). Ventricular fibrillation was electrically induced in 24 male rats and left untreated for 8 min followed by defibrillation after 8 min of cardiopulmonary resuscitation (CPR). Rats were randomized 1:1:1 to the NHE-1 inhibitor zoniporide or vehicle during CPR and disodium carbonate/sodium bicarbonate buffer or normal saline (30 ml/kg) after ROSC. Survival at 240 min declined from 100% with Zoniporide/Saline to 50% with Zoniporide/Buffer and 25% with Vehicle/Buffer (P = 0.004), explained by worsening postresuscitation myocardial dysfunction. Marked alkalemia occurred after buffer administration along with lactatemia that was maximal after Vehicle/Buffer, attenuated by Zoniporide/Buffer, and minimal with Zoniporide/Saline [13.3 ± 4.8 (SD), 9.2 ± 4.6, and 2.7 ± 1.0 mmol/l; P ≤ 0.001]. We attributed the intense postresuscitation lactatemia to enhanced glycolysis consequent to severe buffer-induced alkalemia transmitted intracellularly by an active NHE-1. We attributed the worsened postresuscitation myocardial dysfunction also to severe alkalemia intensifying Na + entry via NHE-1 with consequent Ca 2+ overload injuring mitochondria, evidenced by increased plasma cytochrome c Both buffer-induced effects were ameliorated by zoniporide. Accordingly, buffer-induced alkalemia after ROSC worsened myocardial function and survival, likely through enhancing NHE-1 activity. Zoniporide attenuated these effects and uncovered a complex postresuscitation acid-base physiology whereby blood pH drives NHE-1 activity and compromises mitochondrial function and integrity along with myocardial function and survival.

Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter

USGS Publications Warehouse

Yelenik, Stephanie G.

2017-01-01

Large areas of tropical forest have been cleared and planted with exotic grass species for use as cattle pasture. These often remain persistent grasslands after grazer removal, which is problematic for restoring native forest communities. It is often hoped that remnant and/or planted trees can jump-start forest succession; however, there is little mechanistic information on how different canopy species affect community trajectories. To investigate this, I surveyed understory communities, exotic grass biomass, standing litter pools, and soil properties under two dominant canopy trees—Metrosideros polymorpha (‘ōhi‘a) and Acacia koa (koa)—in recovering Hawaiian forests. I then used structural equation models (SEMs) to elucidate direct and indirect effects of trees on native understory. Native understory communities developed under ‘ōhi‘a, which had larger standing litter pools, lower soil nitrogen, and lower exotic grass biomass than koa. This pattern was variable, potentially due to historical site differences and/or distance to intact forest. Koa, in contrast, showed little understory development. Instead, data suggest that increased soil nitrogen under koa leads to high grass biomass that stalls native recruitment. SEMs suggested that indirect effects of trees via litter and soils were as or more important than direct effects for determining native cover. It is suggested that diverse plantings which incorporate species that have high carbon to nitrogen ratios may help ameliorate the negative indirect effects of koa on natural understory regeneration.

Assessing protected area effectiveness using surrounding (buffer) areas environmentally similar to the target area.

PubMed

Mas, Jean-François

2005-06-01

Many studies are based on the assumption that an area and its surrounding (buffer) area present similar environmental conditions and can be compared. For example, in order to assess the effectiveness of a protected area, the land use/cover changes are compared inside the park with its surroundings. However, the heterogeneity in spatial variables can bias this assessment: we have shown that most of the protected areas in Mexico present significant environmental differences between their interior and their surroundings. Therefore, a comparison that aims at assessing the effectiveness of conservation strategies, must be cautioned. In this paper, a simple method which allows the generation of a buffer area that presents similar conditions with respect to a set of environmental variables is presented. The method was used in order to assess the effectiveness of the Calakmul Biosphere Reserve, a protected area located in the south-eastern part of Mexico. The annual rate of deforestation inside the protected area, the standard buffer area (based upon distance from the protected area only) and the similar buffer area (taking into account distance along with some environmental variables) were 0.3, 1.3 and 0.6%, respectively. These results showed that the protected area was effective in preventing land clearing, but that the comparison with the standard buffer area gave an over-optimistic vision of its effectiveness.

76 FR 33337 - Endangered Species Recovery Permit Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

... No. TE-036090 Applicant: Virginia S. Moran, Grass Valley, California. The applicant requests a permit... sunburst), Orcutttia pilosa (hairy Orcutt grass), Orcuttia viscida (Sacramento Orcutt grass), Tuctoria greenei (Green's awnless Orcutt grass), Tuctoria mucronata (Mucronata Orcutt grass), and Sidalcea keckii...

40 CFR 180.547 - Prohexadione calcium; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... byproducts, except kidney 0.05 Grass, forage 1 0.10 Grass, hay 1 0.10 Grass, seed screenings 1 3.5 Grass... kidney 0.05 1Registration is limited to grass grown for seed. (b) Section 18 emergency exemptions...

40 CFR 180.547 - Prohexadione calcium; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... byproducts, except kidney 0.05 Grass, forage 1 0.10 Grass, hay 1 0.10 Grass, seed screenings 1 3.5 Grass... kidney 0.05 1Registration is limited to grass grown for seed. (b) Section 18 emergency exemptions...

Exserohilum rostratum: characterization of a cross-kingdom pathogen of plants and humans.

PubMed

Sharma, Kalpana; Goss, Erica M; Dickstein, Ellen R; Smith, Matthew E; Johnson, Judith A; Southwick, Frederick S; van Bruggen, Ariena H C

2014-01-01

Pathogen host shifts represent a major source of new infectious diseases. There are several examples of cross-genus host jumps that have caused catastrophic epidemics in animal and plant species worldwide. Cross-kingdom jumps are rare, and are often associated with nosocomial infections. Here we provide an example of human-mediated cross-kingdom jumping of Exserohilum rostratum isolated from a patient who had received a corticosteroid injection and died of fungal meningitis in a Florida hospital in 2012. The clinical isolate of E. rostratum was compared with two plant pathogenic isolates of E. rostratum and an isolate of the closely related genus Bipolaris in terms of morphology, phylogeny, and pathogenicity on one C3 grass, Gulf annual rye grass (Lolium multiflorum), and two C4 grasses, Japanese stilt grass (Microstegium vimineum) and bahia grass (Paspalum notatum). Colony growth and color, as well as conidia shape and size were the same for the clinical and plant isolates of E. rostratum, while these characteristics differed slightly for the Bipolaris sp. isolate. The plant pathogenic and clinical isolates of E. rostratum were indistinguishable based on morphology and ITS and 28S rDNA sequence analysis. The clinical isolate was as pathogenic to all grass species tested as the plant pathogenic strains that were originally isolated from plant hosts. The clinical isolate induced more severe symptoms on stilt grass than on rye grass, while this was the reverse for the plant isolates of E. rostratum. The phylogenetic similarity between the clinical and plant-associated E. rostratum isolates and the ability of the clinical isolate to infect plants suggests that a plant pathogenic strain of E. rostratum contaminated the corticosteroid injection fluid and was able to cause systemic disease in the affected patient. This is the first proof that a clinical isolate of E. rostratum is also an effective plant pathogen.

Exserohilum rostratum: Characterization of a Cross-Kingdom Pathogen of Plants and Humans

PubMed Central

Sharma, Kalpana; Goss, Erica M.; Dickstein, Ellen R.; Smith, Matthew E.; Johnson, Judith A.; Southwick, Frederick S.; van Bruggen, Ariena H. C.

2014-01-01

Pathogen host shifts represent a major source of new infectious diseases. There are several examples of cross-genus host jumps that have caused catastrophic epidemics in animal and plant species worldwide. Cross-kingdom jumps are rare, and are often associated with nosocomial infections. Here we provide an example of human-mediated cross-kingdom jumping of Exserohilum rostratum isolated from a patient who had received a corticosteroid injection and died of fungal meningitis in a Florida hospital in 2012. The clinical isolate of E. rostratum was compared with two plant pathogenic isolates of E. rostratum and an isolate of the closely related genus Bipolaris in terms of morphology, phylogeny, and pathogenicity on one C3 grass, Gulf annual rye grass (Lolium multiflorum), and two C4 grasses, Japanese stilt grass (Microstegium vimineum) and bahia grass (Paspalum notatum). Colony growth and color, as well as conidia shape and size were the same for the clinical and plant isolates of E. rostratum, while these characteristics differed slightly for the Bipolaris sp. isolate. The plant pathogenic and clinical isolates of E. rostratum were indistinguishable based on morphology and ITS and 28S rDNA sequence analysis. The clinical isolate was as pathogenic to all grass species tested as the plant pathogenic strains that were originally isolated from plant hosts. The clinical isolate induced more severe symptoms on stilt grass than on rye grass, while this was the reverse for the plant isolates of E. rostratum. The phylogenetic similarity between the clinical and plant-associated E. rostratum isolates and the ability of the clinical isolate to infect plants suggests that a plant pathogenic strain of E. rostratum contaminated the corticosteroid injection fluid and was able to cause systemic disease in the affected patient. This is the first proof that a clinical isolate of E. rostratum is also an effective plant pathogen. PMID:25285444

Use of bicarbonate buffer systems for dissolution characterization of enteric-coated proton pump inhibitor tablets.

PubMed

Shibata, Hiroko; Yoshida, Hiroyuki; Izutsu, Ken-Ichi; Goda, Yukihiro

2016-04-01

The aim of this study was to assess the effects of buffer systems (bicarbonate or phosphate at different concentrations) on the in vitro dissolution profiles of commercially available enteric-coated tablets. In vitro dissolution tests were conducted using an USP apparatus II on 12 enteric-coated omeprazole and rabeprazole tablets, including innovator and generic formulations in phosphate buffers, bicarbonate buffers and a media modified Hanks (mHanks) buffer. Both omeprazole and rabeprazole tablets showed similar dissolution profiles among products in the compendial phosphate buffer system. However, there were large differences between products in dissolution lag time in mHanks buffer and bicarbonate buffers. All formulations showed longer dissolution lag times at lower concentrations of bicarbonate or phosphate buffers. The dissolution rank order of each formulation differed between mHanks buffer and bicarbonate buffers. A rabeprazole formulation coated with a methacrylic acid copolymer showed the shortest lag time in the high concentration bicarbonate buffer, suggesting varied responses depending on the coating layer and buffer components. Use of multiple dissolution media during in vitro testing, including high concentration bicarbonate buffer, would contribute to the efficient design of enteric-coated drug formulations. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

Global grass (Poaceae) success underpinned by traits facilitating colonization, persistence and habitat transformation.

PubMed

Linder, H P; Lehmann, Caroline E R; Archibald, Sally; Osborne, Colin P; Richardson, David M

2018-05-01

Poaceae (the grasses) is arguably the most successful plant family, in terms of its global occurrence in (almost) all ecosystems with angiosperms, its ecological dominance in many ecosystems, and high species richness. We suggest that the success of grasses is best understood in context of their capacity to colonize, persist, and transform environments (the "Viking syndrome"). This results from combining effective long-distance dispersal, efficacious establishment biology, ecological flexibility, resilience to disturbance and the capacity to modify environments by changing the nature of fire and mammalian herbivory. We identify a diverse set of functional traits linked to dispersal, establishment and competitive abilities. Enhanced long-distance dispersal is determined by anemochory, epizoochory and endozoochory and is facilitated via the spikelet (and especially the awned lemma) which functions as the dispersal unit. Establishment success could be a consequence of the precocious embryo and large starch reserves, which may underpin the extremely short generation times in grasses. Post-establishment genetic bottlenecks may be mitigated by wind pollination and the widespread occurrence of polyploidy, in combination with gametic self-incompatibility. The ecological competitiveness of grasses is corroborated by their dominance across the range of environmental extremes tolerated by angiosperms, facilitated by both C 3 and C 4 photosynthesis, well-developed frost tolerance in several clades, and a sympodial growth form that enabled the evolution of both annual and long-lived life forms. Finally, absence of investment in wood (except in bamboos), and the presence of persistent buds at or below ground level, provides tolerance of repeated defoliation (whether by fire, frost, drought or herbivores). Biotic modification of environments via feedbacks with herbivory or fire reinforce grass dominance leading to open ecosystems. Grasses can be both palatable and productive, fostering high biomass and diversity of mammalian herbivores. Many grasses have a suite of architectural and functional traits that facilitate frequent fire, including a tufted growth form, and tannin-like substances in leaves which slow decomposition. We mapped these traits over the phylogeny of the Poales, spanning the grasses and their relatives, and demonstrated the accumulation of traits since monocots originated in the mid-Cretaceous. Although the sympodial growth form is a monocot trait, tillering resulting in the tufted growth form most likely evolved within the grasses. Similarly, although an ovary apparently constructed of a single carpel evolved in the most recent grass ancestor, spikelets and the awned lemma dispersal units evolved within the grasses. Frost tolerance and C 4 photosynthesis evolved relatively late (late Palaeogene), and the last significant trait to evolve was probably the production of tannins, associated with pyrophytic savannas. This fits palaeobotanical data, suggesting several phases in the grass success story: from a late Cretaceous origin, to occasional tropical grassland patches in the later Palaeogene, to extensive C 3 grassy woodlands in the early-middle Miocene, to the dramatic expansion of the tropical C 4 grass savannas and grasslands in the Pliocene, and the C 3 steppe grasslands during the Pleistocene glacial periods. Modern grasslands depend heavily on strongly seasonal climates, making them sensitive to climate change. © 2017 Cambridge Philosophical Society.

Effects of sediment burial on grass carp, Ctenopharyngodon idella (Valenciennes,1844), eggs

USGS Publications Warehouse

George, Amy E.; Chapman, Duane C.; Deters, Joseph E.; Erwin, Susannah O.; Hayer, Cari-Ann

2015-01-01

It is thought that grass carp (Ctenopharyngodon idella) eggs must remain suspended in the water column in order to hatch successfully. Using sand, the effects of varying sediment levels on grass carp eggs were tested at different developmental states and temperatures. Survival was high (15–35%, depending on temperature and trial) in the unburied treatment where eggs rested on a sand bed but were not covered by sediment. Survival was lower in the partial burial (5–10%) and very low (0–4%) in the full burial treatment. In all treatments, delayed hatching (organisms remaining in membranes past the stage of hatching competence) was noted. Deformities such as missing heads and pericardial edema occurred at high rates in the partial and full burials. Eggs that come in contact with the benthos and are resuspended in the water column should be considered in embryonic drift models.

Role of mycorrhizal colonization in plant establishment on an alkaline gold mine tailing.

PubMed

Orłowska, Elzbieta; Orłowski, Dariusz; Mesjasz-Przybyłowicz, Jolanta; Turnau, Katarzyna

2011-02-01

The potential role of arbuscular mycorrhizal fungi (AMF) in the revegetation of an alkaline gold mine tailing was studied in Barberton, South Africa. The tailing, characterized by a slow spontaneous plant succession, is colonized by the shrub Dodonaea viscosa and the grasses, Andropogon eucomus and Imperata cylindrica, all colonized by AMF. The effectiveness of mycorrhizal colonization in grasses was tested under laboratory conditions using fungal isolates of various origins. Both grasses were highly mycorrhiza dependent, and the presence of mycorrhizal colonization significantly increased their biomass and survival rates. The fungi originating from the gold tailing were better adapted to the special conditions of the tailing than the control isolate. Although the total colonization rate found for native fungi was lower than for fungi from non-polluted sites, they were more vital and more effective in promoting plant growth. The results obtained might serve as a practical approach to the phytostabilization of alkaline gold tailings.

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. III. Efficacy and safety of unfractionated and high-molecular-weight preparations in rhinoconjunctivitis and asthma.

PubMed

Bousquet, J; Maasch, H J; Hejjaoui, A; Skassa-Brociek, W; Wahl, R; Dhivert, H; Michel, F B

1989-10-01

Specific immunotherapy with unmodified formalinized allergoids is effective in grass-pollen allergy, but systemic reactions have been observed. A high-molecular-weight formalinized allergoid (HMW-GOID) was fractionated by gel filtration, retaining molecules of greater than 85,000 daltons in the expectation of improving safety without sacrificing efficacy. HMW-GOID and unfractionated allergoid (GOID) had a similar allergenic activity assessed by RAST inhibition, but the HMW-GOID preparation was 65 times less reactive when it was tested by skin prick test than the GOID preparation. A double-blind, placebo-controlled study was carried out in grass pollen-allergic patients with placebo (14 patients), GOID (15 patients), and HMW-GOID (13 patients). An additional group of 18 patients was treated by a rush schedule with a standardized orchard grass-pollen extract. A similar mean cumulative dose was administered with both allergoids. The fractionated allergoid only elicited minor systemic reactions similar to reactions elicited by placebo, whereas 20% of patients treated by GOID and 5.5% of patients receiving the standardized extract had a severe systemic reaction. For rhinitis, conjunctivitis, and asthma, the HMW-GOID and the standardized extract had a similar efficacy, significantly greater than placebo. GOID was less effective than the other two active treatments but was significantly more effective than placebo treatment for asthma and conjunctivitis.

[Effects of different patterns surface mulching on soil properties and fruit trees growth and yield in an apple orchard].

PubMed

Zhang, Yi; Xie, Yong-Sheng; Hao, Ming-De; She, Xiao-Yan

2010-02-01

Taking a nine-year-old Fuji apple orchard in Loess Plateau as test object, this paper studied the effects of different patterns surface mulching (clean tillage, grass cover, plastic film mulch, straw mulch, and gravel mulch) on the soil properties and fruit trees growth and yield in this orchard. Grass cover induced the lowest differentiation of soil moisture profile, while gravel mulch induced the highest one. In treatment gravel mulch, the soil moisture content in apple trees root zone was the highest, which meant that there was more water available to apple trees. Surface mulching had significant effects on soil temperature, and generally resulted in a decrease in the maximum soil temperature. The exception was treatment plastic film mulch, in which, the soil temperature in summer exceeded the maximum allowable temperature for continuous root growth and physiological function. With the exception of treatment plastic film mulch, surface mulching increased the soil CO2 flux, which was the highest in treatment grass cover. Surface mulching also affected the proportion of various branch types and fruit yield. The proportion of medium-sized branches and fruit yield were the highest in treatment gravel mulch, while the fruit yield was the lowest in treatment grass cover. Factor analysis indicated that among the test surface mulching patterns, gravel mulch was most suitable for the apple orchards in gully region of Loess Plateau.

75 FR 69666 - Granting of Request for Early Termination of the Waiting Period Under the Premerger Notification...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

....P. G Technicolor S.A. G Thomson 000. G Grass Valley Spain SA. G Brazil GV Newco. G Thomson Licensing SAS. G Grass Valley Germany GmbH. G Grass Valley Australia PTY Limited. G Grass Valley Singapore PTE Ltd. G Canopus Asia Co. Limited. G Grass Valley Canada, Inc. G US GV Newco (to be formed). G Grass...

Functional Group, Biomass, and Climate Change Effects on Ecological Drought in Semiarid Grasslands

NASA Astrophysics Data System (ADS)

Wilson, S. D.; Schlaepfer, D. R.; Bradford, J. B.; Lauenroth, W. K.; Duniway, M. C.; Hall, S. A.; Jamiyansharav, K.; Jia, G.; Lkhagva, A.; Munson, S. M.; Pyke, D. A.; Tietjen, B.

2018-03-01

Water relations in plant communities are influenced both by contrasting functional groups (grasses and shrubs) and by climate change via complex effects on interception, uptake, and transpiration. We modeled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30 year periods. Relative to control vegetation (climate and site-determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally increased biomass (i.e., the effects of invasions that increase community biomass or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought in both current and future climates.

Functional group, biomass, and climate change effects on ecological drought in semiarid grasslands

USGS Publications Warehouse

Wilson, Scott D.; Schlaepfer, Daniel R.; Bradford, John B.; Lauenroth, William K.; Duniway, Michael C.; Hall, Sonia A.; Jamiyansharav, Khishigbayar; Jia, Gensuo; Lkhagva, Ariuntsetseg; Munson, Seth M.; Pyke, David A.; Tietjen, Britta

2018-01-01

Water relations in plant communities are influenced both by contrasting functional groups (grasses, shrubs) and by climate change via complex effects on interception, uptake and transpiration. We modelled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30‐year periods. Relative to control vegetation (climate and site‐determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally‐increased biomass (i.e. the effects of invasions that increase community biomass, or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration, and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought both in current and future climates.

Effects of the statin antihyperlipidemic agent simvastatin on grass shrimp, Palaemonetes pugio.

PubMed

Key, Peter B; Hoguet, Jennifer; Reed, Lou Ann; Chung, Katy W; Fulton, Michael H

2008-04-01

This study investigated lethal effects (i.e., survival) and sublethal effects (glutathione, GSH; lipid peroxidation, LPx; cholesterol, CHL; and acetylcholinesterase, AChE) of the antihyperlipidemic drug simvastatin on larval and adult grass shrimp (Palaemonetes pugio). The 96-h LC50 test for larvae resulted in an estimated LC50 of 1.18 mg/L (95% confidence interval 0.98-1.42 mg/L). The adult 96-h LC50 was >10.0 mg/L. GSH and AChE levels for both the larvae and the adults were not significantly affected by simvastatin exposure. LPx levels in the larvae were significantly higher than controls in the lowest and the highest simvastatin exposures. In adult grass shrimp, LPx levels were highest in the three lowest simvastatin exposures. CHL levels were significantly reduced in larvae at the highest simvastatin exposure level of 1 mg/L while adult CHL was not affected. Both lethal and sublethal effects associated with simvastatin exposure were only observed at concentrations well above those reported in the environment. (Copyright) 2008 Wiley Periodicals, Inc.

Effect of Tylenchorhynchus robustoides on Growth of Buffalo Grass and Western Wheatgrass.

PubMed

Smolik, J D

1982-10-01

Tylenchorhynchus robustoides reduced (P = 0.05) growth of Agropyron smithii (western wheatgrass) at soil temperatures of 20, 25, 30, and 35 C. Growth reduction increased with increasing soil temperatures. Highest populations of T. robustoides were recovered at 25 and 30 C. Clipping weights of Buchloe dactyloides (buffalo grass) were reduced at 25 and 30 C; however, root/crown weights were reduced at 15, 20, 30, and 35 C in nematode infested vs. noninfested soil. Reproduction of T. robustoides was greater at 25, 30, and 35 C than at 20 C on B. dactyloides. In a greenhouse study, T. robustoides reduced clipping and root/crown weights of both grasses 24-64%.

Application of MOS-1 MESSR image to the investigation of wetlands in Poyang Lake

NASA Astrophysics Data System (ADS)

Chen, Shuisen; Li, Yan

1998-08-01

The lake beach and grass moor land is a kind of typical wetlands. The area varies greatly with season in Poyang Lake region. Moreover, the field investigation of wetlands is almost impossible as geographical features and difficulties in transportation. The notes address the potential role of remote sensing in the surveying of the lake beach and grass moor land. In particular, the notes reflect the characteristics relationships between MOS-1 MESSR image and the wetlands. The application results show that MOS-1 MESSR image is effective in surveying the wetland area variation and distribution (lake, river, grass moor, mud flat, sand beach, etc.). detecting lake base shape, and analyzing eco-environment surrounded.

Environmental Assessment for Military Family Housing Privatization Initiative

DTIC Science & Technology

2006-01-01

grass Bouteloua radicosa Grama grass Bouteloua parryi Grama grass Bouteloua barbata Grama grass Cathestecum erectum False grama grass Aristida...Leptonycteris curasoae yerbabuenae Lesser long- nosed bat LE WSC Desert scrub habitat with agave and columnar cacti present as food plants. May Occur

Use of a mixed sericea lespedeza and grass pasture system for control of gastrointestinal nematodes in lambs and kids.

PubMed

Burke, J M; Miller, J E; Mosjidis, J A; Terrill, T H

2012-05-25

Because of a high prevalence of anthelmintic resistance and consumer demand for chemical free meat products, management tools to minimize the need for deworming are needed. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) in a mixed grass or a pure forage system for control of gastrointestinal nematodes (GIN); in other words pasture systems included grass, grass plus SL, or SL alone (Experiments 2 and 3). Selective use of copper oxide wire particles (COWP) based on the FAMACHA(©) system was used to aid in GIN control. In Experiment 1, lambs co-grazed bermudagrass (BG; n=21) or SL in a mixed grass pasture (SLM; n=22) with dams for 14 days. In Experiment 2, lambs grazed BG (n=14), SLM (n=13), or pure SL (SLP; n=13) pastures for 56 days. In Experiment 3, doe kids grazed BG (n=12), SLM (n=13), or SLP (n=13) for 84 days. Animals were fed a 16% crude protein supplement based on NRC requirements and estimated forage quality of pastures, so that 454, 389, and 200 g/lamb (Experiment 2), or 454, 300, and 150 g of supplement/goat (Experiment 3) was fed to BG, SLM, and SLP, respectively. Animals were dewormed with COWP if FAMACHA(©) was >3. Coprocultures were conducted to identify GIN genus. In Experiment 1, FEC were reduced in lambs grazing SLM compared with BG pastures. In Experiment 2, FEC were reduced in SLP compared with BG lambs on all days, and reduced in SLM compared with BG lambs on day 56. Initially, Haemonchus contortus was the predominant nematode, but the population shifted to other species in the SL groups by the end of the study. The mean number of dewormings/lamb was 0.71, 0.20, and 0.21±0.13 for BG, SLM, and SLP groups, respectively. In goats in Experiment 3, Trichostrongylus spp. was the predominant nematode in May and June and H. contortus in July. There was little meaningful effect of forage treatments on GIN infection in kids. Because H. contortus was not the predominant nematode in kids, the integrated approaches used may not have been effective in controlling GIN. Grazing SL was effective for GIN control in lambs in early summer, but the effect was delayed in lambs grazing a mixed SL/grass pasture unless lambs initially grazed with dams. An integrated approach used that included SL grazing and COWP for deworming was effective in lambs. Published by Elsevier B.V.

AmeriFlux CA-Let Alberta - Mixed Grass Prairie

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flanagan, Lawrence B.

This is the AmeriFlux version of the carbon flux data for the site CA-Let Alberta - Mixed Grass Prairie. Site Description - Latitude 49.43° N; Longitude 112.56° W, altitude 951 meters,Mixed Grass Prairie that includes the following major species: Agropyron spp. (Wheat Grasses), Tragopogon dubius (Goat’s Beard), Vicia americana (Wild Vetch), Koleria cristata (June Grass), Eurotia lanata (Winter Fat), Stipa comata (Spear Grass), Achillea millefolium (Yarrow); Artemisia frigida (Pasture Sage); Carex spp. (Sedges), Bouteloua gracilis (Blue Grama Grass). Maximum canopy height varies from year to year

Satisfaction and quality of life of allergic patients following sublingual five-grass pollen tablet immunotherapy in Spain.

PubMed

Antolín-Amerigo, Darío; Tabar, Isabel A; Del Mar Fernández-Nieto, Maria; Callejo-Melgosa, Anna M; Muñoz-Bellido, Francisco J; Martínez-Alonso, José C; Méndez-Alcalde, Jorge D; Reche, Marta; Rodríguez-Trabado, Ana; Rosado-Ingelmo, Ana; Alonso-Gómez, Alicia; Blanco-González, Rosa; Alvarez-Fernandez, José A; Botella, Isabel; Valls, Ana; Cimarra, Mercedes; Blanco, Carlos

2017-01-01

Five-grass pollen tablet is an effective and well-tolerated therapy for patients with allergic rhinoconjunctivitis (ARC). This trial sought to determine the satisfaction and health-related quality of life (HRQoL) of patients undergoing this treatment. This was a cross-sectional, multicentre, observational, naturalistic study, following a discontinuous pre- and co-seasonal five-grass pollen regimen over two seasons in Spain (2012, 2013). The HRQoL of the patients was measured with the specific Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) for adults, adolescent (AdolRQLQ), or paediatric (PRQLQ) patients. Treatment satisfaction was assessed by the Satisfaction Scale for Patients Receiving Allergen Immunotherapy (ESPIA) questionnaire. Patients/investigators were surveyed on beliefs and attitudes towards the five-grass pollen tablet. ARC evolution according to allergic rhinitis and its impact on asthma (ARIA) criteria and treatment adherence were evaluated. Among the 591 ARC patients included, the mean (SD) HRQoL scores were 1.40 (1.1) in adults, 1.33 (1.1) in adolescents, and 1.15 (1.1) in children, indicating low levels of impairment (scale 0-6). ESPIA answers showed high levels of satisfaction, with an average score of 69.2 (scale 0-100). According to ARIA criteria, 88.2% of patients reported improvement of ARC. Moreover, this was accompanied by a reduced use of symptomatic medication. Adherence to treatment was estimated at 96.8%. In general, both patients and specialists exhibited a positive attitude towards five-grass pollen tablet treatment. ARC patients treated with five-grass pollen tablet showed favourable levels of HRQoL and treatment satisfaction, with concomitant improvements in ARC and symptomatic medication use, which translated into high levels of treatment adherence and a positive attitude towards five-grass pollen tablet.

Satisfaction and quality of life of allergic patients following sublingual five-grass pollen tablet immunotherapy in Spain

PubMed Central

Antolín-Amerigo, Darío; Tabar, Isabel A; del Mar Fernández-Nieto, Maria; Callejo-Melgosa, Anna M; Muñoz-Bellido, Francisco J; Martínez-Alonso, José C; Méndez-Alcalde, Jorge D; Reche, Marta; Rodríguez-Trabado, Ana; Rosado-Ingelmo, Ana; Alonso-Gómez, Alicia; Blanco-González, Rosa; Alvarez-Fernandez, José A; Botella, Isabel; Valls, Ana; Cimarra, Mercedes; Blanco, Carlos

2017-01-01

Background Five-grass pollen tablet is an effective and well-tolerated therapy for patients with allergic rhinoconjunctivitis (ARC). This trial sought to determine the satisfaction and health-related quality of life (HRQoL) of patients undergoing this treatment. Methods This was a cross-sectional, multicentre, observational, naturalistic study, following a discontinuous pre- and co-seasonal five-grass pollen regimen over two seasons in Spain (2012, 2013). The HRQoL of the patients was measured with the specific Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) for adults, adolescent (AdolRQLQ), or paediatric (PRQLQ) patients. Treatment satisfaction was assessed by the Satisfaction Scale for Patients Receiving Allergen Immunotherapy (ESPIA) questionnaire. Patients/investigators were surveyed on beliefs and attitudes towards the five-grass pollen tablet. ARC evolution according to allergic rhinitis and its impact on asthma (ARIA) criteria and treatment adherence were evaluated. Results Among the 591 ARC patients included, the mean (SD) HRQoL scores were 1.40 (1.1) in adults, 1.33 (1.1) in adolescents, and 1.15 (1.1) in children, indicating low levels of impairment (scale 0–6). ESPIA answers showed high levels of satisfaction, with an average score of 69.2 (scale 0–100). According to ARIA criteria, 88.2% of patients reported improvement of ARC. Moreover, this was accompanied by a reduced use of symptomatic medication. Adherence to treatment was estimated at 96.8%. In general, both patients and specialists exhibited a positive attitude towards five-grass pollen tablet treatment. Conclusion ARC patients treated with five-grass pollen tablet showed favourable levels of HRQoL and treatment satisfaction, with concomitant improvements in ARC and symptomatic medication use, which translated into high levels of treatment adherence and a positive attitude towards five-grass pollen tablet. PMID:29225657

Effects of glucose, insulin and triiodothyroxine on leptin and leptin receptor expression and the effects of leptin on activities of enzymes related to glucose metabolism in grass carp (Ctenopharyngodon idella) hepatocytes.

PubMed

Lu, Rong-Hua; Zhou, Yi; Yuan, Xiao-Chen; Liang, Xu-Fang; Fang, Liu; Bai, Xiao-Li; Wang, Min; Zhao, Yu-Hua

2015-08-01

Leptin is an important regulator of appetite and energy expenditure in mammals, but its role in fish metabolism control is poorly understood. Our previous studies demonstrated that leptin has an effect on the regulation of food intake and energy expenditure as well as lipid metabolism (stimulation of lipolysis and inhibition of adipogenesis) in the grass carp Ctenopharyngodon idella. To further investigate the role of leptin in fish, the effects of glucose, insulin and triiodothyroxine (T3) on the expression levels of leptin and leptin receptor (Lepr) and the effects of leptin on the activities of critical glucose metabolism enzymes in grass carp hepatocytes were evaluated in the present study. Our data indicated that leptin gene expression was induced by glucose in a dose-dependent manner, while Lepr gene expression exhibited a biphasic change. A high dose of insulin (100 ng/mL) significantly up-regulated the expression of leptin and Lepr. Leptin expression was markedly up-regulated by a low concentration of T3 but inhibited by a high concentration of T3. T3 up-regulated Lepr expression in a dose-dependent manner. Together, these data suggest that leptin had a close relationship with three factors (glucose, insulin and T3) and might participate in the regulation of glucose metabolism in grass carp. In addition, we also found that leptin affected the activities of key enzymes that are involved in glucose metabolism, which might be mediated by insulin receptor substrate-phosphoinositol 3-kinase signaling.

Responses of tropical native and invader C4 grasses to water stress, clipping and increased atmospheric CO2 concentration.

PubMed

Baruch, Zdravko; Jackson, Robert B

2005-10-01

The invasion of African grasses into Neotropical savannas has altered savanna composition, structure and function. The projected increase in atmospheric CO(2) concentration has the potential to further alter the competitive relationship between native and invader grasses. The objective of this study was to quantify the responses of two populations of a widespread native C(4) grass (Trachypogon plumosus) and two African C(4) grass invaders (Hyparrhenia rufa and Melinis minutiflora) to high CO(2) concentration interacting with two primary savanna stressors: drought and herbivory. Elevated CO(2) increased the competitive potential of invader grasses in several ways. Germination and seedling size was promoted in introduced grasses. Under high CO(2), the relative growth rate of young introduced grasses was twice that of native grass (0.58 g g(-1) week(-1) vs 0.25 g g(-1) week(-1)). This initial growth advantage was maintained throughout the course of the study. Well-watered and unstressed African grasses also responded more to high CO(2) than did the native grass (biomass increases of 21-47% compared with decreases of 13-51%). Observed higher water and nitrogen use efficiency of invader grasses may aid their establishment and competitive strength in unfertile sites, specially if the climate becomes drier. In addition, high CO(2) promoted lower leaf N content more in the invader grasses. The more intensive land use, predicted to occur in this region, may interact with high CO(2) to favor the African grasses, as they generally recovered faster after simulated herbivory. The superiority of invader grasses under high CO(2) suggests further increases in their competitive strength and a potential increased rate of displacement of the native savannas in the future by grasslands dominated by introduced African species.

Early growth tolerances of grasses, shrubs, and trees to boron in tunnel spoil

Treesearch

Parker F. Pratt; Eamor C. Nord; Francis L. Bair

1971-01-01

The effects of boron and salts in spoil material on survival and growth of 44 grass, shrub, and tree species were tested under greenhouse conditions. The spoil used was from the Angeles Tunnel of the California Aqueduct's West Branch now being built. Several species within each plant group apparently can tolerate boron, but field tests will be needed before most...

26 CFR 1.6033-2 - Returns by exempt organizations (taxable years beginning after December 31, 1969) and returns by...

Code of Federal Regulations, 2010 CFR

2010-04-01

... contractors who received in excess of $30,000 for the year for the performance of such services. (h) A... expenditures, grass roots expenditures, exempt purpose expenditures, lobbying nontaxable amount, and grass... meaning of § 1.501(h)-3(c)(7)), if the organization has an election under section 501(h) in effect for the...

A comparison of soil organic carbon stocks between residential turf grass and native soil

Treesearch

Richard V. Pouyat; Ian D. Yesilonis; Nancy E. Golubiewski

2009-01-01

A central principle in urban ecological theory implies that in urbanized landscapes anthropogenic drivers will dominate natural drivers in the control of soil organic carbon storage (SOC). To assess the effect of urban land-use change on the storage of SOC, we compared SOC stocks of turf grass and native cover types of two metropolitan areas (Baltimore, MD, and Denver...

Selective excitation of window and buffer layers in chalcopyrite devices and modules

DOE PAGES

Glynn, Stephen; Repins, Ingrid L.; Burst, James M.; ...

2018-02-02

Window and buffer layers in chalcopyrite devices are well known to affect junctions, conduction, and photo-absorption properties of the device. Some of these layers, particularly 'buffers,' which are deposited directly on top of the absorber, exhibit metastable effects upon exposure to light. Thus, to understand device performance and/or metastability, it is sometimes desirable to selectively excite different layers in the device stack. Absorption characteristics of various window and buffer layers used in chalcopyrite devices are measured. These characteristics are compared with emission spectra of common and available light sources that might be used to optically excite such layers. Effects ofmore » the window and buffer absorption on device quantum efficiency and metastability are discussed. For the case of bath-deposited Zn(O,S) buffers, we conclude that this layer is not optically excited in research devices or modules. Furthermore, this provides a complimentary mechanism to the chemical differences that may cause long time constants (compared to devices with CdS buffers) associated with reaching a stable 'light-soaked' state.« less

Study of the effects of GaN buffer layer quality on the dc characteristics of AlGaN/GaN high electron mobility transistors

DOE PAGES

Ahn, Shihyun; Zhu, Weidi; Dong, Chen; ...

2015-04-21

Here we studied the effect of buffer layer quality on dc characteristics of AlGaN/GaN high electron mobility (HEMTs). AlGaN/GaN HEMT structures with 2 and 5 μm GaN buffer layers on sapphire substrates from two different vendors with the same Al concentration of AlGaN were used. The defect densities of HEMT structures with 2 and 5 μm GaN buffer layer were 7 × 10 9 and 5 × 10 8 cm ₋2, respectively, as measured by transmission electron microscopy. There was little difference in drain saturation current or in transfer characteristics in HEMTs on these two types of buffer. However, theremore » was no dispersion observed on the nonpassivated HEMTs with 5 μm GaN buffer layer for gate-lag pulsed measurement at 100 kHz, which was in sharp contrast to the 71% drain current reduction for the HEMT with 2 μm GaN buffer layer.« less

Selective excitation of window and buffer layers in chalcopyrite devices and modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glynn, Stephen; Repins, Ingrid L.; Burst, James M.

Window and buffer layers in chalcopyrite devices are well known to affect junctions, conduction, and photo-absorption properties of the device. Some of these layers, particularly 'buffers,' which are deposited directly on top of the absorber, exhibit metastable effects upon exposure to light. Thus, to understand device performance and/or metastability, it is sometimes desirable to selectively excite different layers in the device stack. Absorption characteristics of various window and buffer layers used in chalcopyrite devices are measured. These characteristics are compared with emission spectra of common and available light sources that might be used to optically excite such layers. Effects ofmore » the window and buffer absorption on device quantum efficiency and metastability are discussed. For the case of bath-deposited Zn(O,S) buffers, we conclude that this layer is not optically excited in research devices or modules. Furthermore, this provides a complimentary mechanism to the chemical differences that may cause long time constants (compared to devices with CdS buffers) associated with reaching a stable 'light-soaked' state.« less

A Tensile Strength of Bermuda Grass and Vetiver Grass in Terms of Root Reinforcement Ability Toward Soil Slope Stabilization

NASA Astrophysics Data System (ADS)

Noorasyikin, M. N.; Zainab, M.

2016-07-01

An examination on root characteristics and root properties has been implemented in this study. Two types of bioengineering were chose which are Vetiver grass and Bermuda grass as these grasses were widely applied for slope stabilization. The root samples were taken to the laboratory to investigate its classification, characteristics and strength. The root of both grasses was found grow with fibrous root matrix system. In terms of root anchorage, the root matrix system of Vetiver grass was exhibits more strengthen than the Bermuda grass. However, observation on root image from Scanning Electron Microscope test reveals that the root of Vetiver grass becomes non-porous as the moisture content reduced. Meanwhile, the root tensile strength of Bermuda grass was obtained acquired low value with higher percentage of moisture content, root morphology and bonding strength. The results indicated that the root tensile strength is mainly influence by percentage of moisture content and root morphology.

Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest

PubMed Central

2015-01-01

Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1–2 years) and long-term (~10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (~13m) forested buffers on each side of the stream, and sites with wider (~30m) and more variable width unharvested buffer. Buffer treatments exhibited a 31–44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63–74%) relative to the controls (29%). We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals) for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29%) and Wide buffers (short-term: 21%; long-term 93%) relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that range from ~22–25 m. Guidelines for this region are within the range of buffers included in our study, in which we observed no evidence for avian species loss or for a decline in species abundance (including riparian associated species). PMID:26637120

Physical and vegetative characteristics of a relocated stream reach, constructed wetland, and riparian buffer, Upper Saucon Township, Lehigh County, Pennsylvania, 2000-04

USGS Publications Warehouse

Chaplin, Jeffrey J.; White, Kirk E.; Loper, Connie A.

2006-01-01

The U.S. Geological Survey, in cooperation with the Pennsylvania Department of Transportation, Engineering District 5-0, investigated physical and vegetative changes within a relocated stream reach, constructed wetland, and riparian buffer from September 2000 to October 2004. This report presents an evaluation of data collected using methods from multiple sources that have been adapted into a consistent approach. This approach is intended to satisfy a need for consistent collection of different types of data with the goal of transferring technology and findings to similar projects. Survey data indicate that adjustment of the upstream part of the relocated stream reach slowed over the monitoring period, but the downstream channel remains unstable as evidenced by excessive deposition. Upstream migration of a nick point has slowed or stopped altogether as of the 2003 assessment when this feature came in contact with the upstream-most part of the channel that is lined with riprap. Documented streambed erosion in the upstream cross sections, along with deposition downstream, has resulted in an overall decrease in slope of the stream channel over the monitoring period. Most streambed erosion took place prior to the 2002 assessment when annual mean streamflows were less than those in the final 2 years of monitoring. An abundance of fine sediment dominates the substrate of the relocated channel. Annual fluctuations of large particles within each cross section demonstrates the capacity of the relocated channel to transport the entire range of sediment. The substrate within the 0.28-acre constructed wetland (a mixture of soil from an off-site naturally occurring wetland and woodchips) supported a hydrophytic-vegetation community throughout the investigation. Eleocharis obtusa (spike rush), an obligate-wetland herb, was the most prevalent species, having a maximum areal cover of 90 percent in fall 2001 and a minimum of 23 percent in fall 2004. Drought-like conditions in water year 2002 (cumulative precipitation was 28.11 inches) allowed species like Panicum dichotomiflorum (witch grass), Salix sp. (willow), Leersia oryzoides (rice cutgrass), and Echinocloa crusgalli (barnyard grass) to become established by fall 2002. Above-average precipitation in water years 2003 and 2004 (58.55 and 53.17 inches, respectively) coincided with increased areal cover by E. obtusa in fall 2003 (56 percent) and decreased areal cover in fall 2004 (23 percent). Pond-like conditions that probably persisted throughout the 2004 growing season favored aquatic species like Alisma subcordatum (water plantain) to the detriment of many emergent species, including E. obtusa. Despite the pond-like conditions, L. oryzoides, an obligate-wetland grass, increased in areal cover (from 12 to 34 percent) between the 2003 and 2004 growing seasons because it was established in the higher elevations and the peripheral areas of the constructed wetland that were less prone to persistent inundation. Canopy development by trees and shrubs in the riparian buffer was initially (fall 2000) poor (39.7 percent), resulting in more available sunlight for the herbaceous understory than in any other growing season. As a result, areal cover of herbaceous species and trees and shrubs less than 1-meter tall was 108 percent in fall 2000 with Lolium perenne (perennial rye), Polygonum persicaria (lady's thumb), and Setaria faberi (foxtail) collectively contributing nearly half the cover (59.2 percent). Because of increases in canopy cover by trees and shrubs (39.7 percent in fall 2000 to 127 percent in fall 2004), herbaceous cover decreased to 76 percent by the fall of 2001 and varied between 72 and 77 percent for the rest of the study period. Tree density in the riparian buffer ranged from 3,078 and 4,130 plants per acre (fall 2000 and 2003, respectively) over the study period but essentially remained constant after fall 2001; computations reported each fall between fall 2001 and fall 2004 are within 10 percent of one another. When the study ended in fall 2004, Acer negundo (box elder) and Fraxinus pennsylvanica (green ash) were the most populous tree species (1,526 and 1,084 plants per acre, respectively) followed by Quercus bicolor (swamp white oak; 720 plants per acre). A. negundo, F. pennsylvanica, and Q. bicolor also contributed the greatest areal cover in fall 2004 (31.2, 24.0, and 18.5 percent,respectively). 

Experimental studies of the effects of buffered particle dampers attached to a multi-degree-of-freedom system under dynamic loads

NASA Astrophysics Data System (ADS)

Lu, Zheng; Lu, Xilin; Lu, Wensheng; Masri, Sami F.

2012-04-01

This paper presents a systematic experimental investigation of the effects of buffered particle dampers attached to a multi-degree-of-freedom (mdof) system under different dynamic loads (free vibration, random excitation as well as real onsite earthquake excitations), and analytical/computational study of such a system. A series of shaking table tests of a three-storey steel frame with the buffered particle damper system are carried out to evaluate the performance and to verify the analysis method. It is shown that buffered particle dampers have good performance in reducing the response of structures under dynamic loads, especially under random excitation case. It can effectively control the fundamental mode of the mdof primary system; however, the control effect for higher modes is variable. It is also shown that, for a specific container geometry, a certain mass ratio leads to more efficient momentum transfer from the primary system to the particles with a better vibration attenuation effect, and that buffered particle dampers have better control effect than the conventional rigid ones. An analytical solution based on the discrete element method is also presented. Comparison between the experimental and computational results shows that reasonably accurate estimates of the response of a primary system can be obtained. Properly designed buffered particle dampers can effectively reduce the response of lightly damped mdof primary system with a small weight penalty, under different dynamic loads.

Photo-induced wettability of TiO{sub 2} film with Au buffer layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam

2014-04-24

The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

Effect of annealing on magnetoresistance and microstructure of multilayered CoFe/Cu systems with different buffer layer

NASA Astrophysics Data System (ADS)

Bannikova, N. S.; Milyaev, M. A.; Naumova, L. I.; Proglyado, V. V.; Krinitsina, T. P.; Chernyshova, T. A.; Ustinov, V. V.

2015-02-01

The effects of annealing on the structure, magnetic hysteresis, and magnetoresistance of [Co90Fe10(15 Å)/Cu(23 Å)] n superlattices with Cr and Co90Fe10 buffer layers of different thicknesses have been studied. The optimum temperature and time of annealing that increase the magnetoresistance were shown to depend on the buffer layer thickness. The coefficients of effective interlayer diffusion due to the annealing have been determined.

40 CFR 180.34 - Tests on the amount of residue remaining.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., barley, oats, rice, rye (each in grain form). (25) Alfalfa, Bermuda grass, bluegrass, brome grass, clovers, cowpea hay, fescue, lespedeza, lupines, orchard grass, peanut hay, peavine hay, rye grass, soybean hay, sudan grass, timothy, and vetch. (26) Corn forage, sorghum forage. (27) Sugarcane, cane...

40 CFR 180.34 - Tests on the amount of residue remaining.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., barley, oats, rice, rye (each in grain form). (25) Alfalfa, Bermuda grass, bluegrass, brome grass, clovers, cowpea hay, fescue, lespedeza, lupines, orchard grass, peanut hay, peavine hay, rye grass, soybean hay, sudan grass, timothy, and vetch. (26) Corn forage, sorghum forage. (27) Sugarcane, cane...

Crop-associated virus reduces the rooting depth of non-crop perennial native grass more than non-crop-associated virus with known viral suppressor of RNA silencing (VSR).

PubMed

Malmstrom, Carolyn M; Bigelow, Patrick; Trębicki, Piotr; Busch, Anna K; Friel, Colleen; Cole, Ellen; Abdel-Azim, Heba; Phillippo, Colin; Alexander, Helen M

2017-09-15

As agricultural acreage expanded and came to dominate landscapes across the world, viruses gained opportunities to move between crop and wild native plants. In the Midwestern USA, virus exchange currently occurs between widespread annual Poaceae crops and remnant native perennial prairie grasses now under consideration as bioenergy feedstocks. In this region, the common aphid species Rhopalosiphum padi L. (the bird cherry-oat aphid) transmits several virus species in the family Luteoviridae, including Barley yellow dwarf virus (BYDV-PAV, genus Luteovirus) and Cereal yellow dwarf virus (CYDV-RPV and -RPS, genus Polerovirus). The yellow dwarf virus (YDV) species in these two genera share genetic similarities in their 3'-ends, but diverge in the 5'-regions. Most notably, CYDVs encode a P0 viral suppressor of RNA silencing (VSR) absent in BYDV-PAV. Because BYDV-PAV has been reported more frequently in annual cereals and CYDVs in perennial non-crop grasses, we examine the hypothesis that the viruses' genetic differences reflect different affinities for crop and non-crop hosts. Specifically, we ask (i) whether CYDVs might persist within and affect a native non-crop grass more strongly than BYDV-PAV, on the grounds that the polerovirus VSR could better moderate the defenses of a well-defended perennial, and (ii) whether the opposite pattern of effects might occur in a less defended annual crop. Because previous work found that the VSR of CYDV-RPS possessed greater silencing suppressor efficiency than that of CYDV-RPV, we further explored (iii) whether a novel grass-associated CYDV-RPS isolate would influence a native non-crop grass more strongly than a comparable CYDV-RPV isolate. In growth chamber studies, we found support for this hypothesis: only grass-associated CYDV-RPS stunted the shoots and crowns of Panicum virgatum L. (switchgrass), a perennial native North American prairie grass, whereas crop-associated BYDV-PAV (and coinfection with BYDV-PAV and CYDV-RPS) most stunted annual Avena sativa L. (oats). These findings suggest that some of the diversity in grass-infecting Luteoviridae reflects viral capacity to modulate defenses in different host types. Intriguingly, while all virus treatments also reduced root production in both host species, only crop-associated BYDV-PAV (or co-infection) reduced rooting depths. Such root effects may increase host susceptibility to drought, and indicate that BYDV-PAV pathogenicity is determined by something other than a P0 VSR. These findings contribute to growing evidence that pathogenic crop-associated viruses may harm native species as well as crops. Critical next questions include the extent to which crop-associated selection pressures drive viral pathogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Different Buffers on the Construction of Aptamer Sensors

NASA Astrophysics Data System (ADS)

Yu, Quan; Dai, Zhao; Wu, Wenjing; Zhu, Haijia; Ji, Luyu

2017-12-01

In this paper, the effect of different buffers, PBS and TBE, on the construction of an aptamer sensor (apt sensor) for ATP was investigated. The apt sensor was based on fluorescence energy resonance transfer (FRET), when the energy donor was 5'-carboxyfluorescein (5'-FAM) and the energy receptor was Au nanoparticles (AuNPs), respectively. Both the donor and acceptor were conjugated with complementary and single stranded DNA (ssDNA). The fluorescent changes of the sensors were measured to investigate the influence of different buffers during the whole preparation and detection process. The results indicated that when the AuNPs and ssDNA (Au-DNA1) were conjugated in PBS buffer, the corresponding apt sensors would obtain a better detection ability of ATP than in TBE buffer.

Effect of sample storage temperature and buffer formulation on faecal immunochemical test haemoglobin measurements.

PubMed

Symonds, Erin L; Cole, Stephen R; Bastin, Dawn; Fraser, Robert Jl; Young, Graeme P

2017-12-01

Objectives Faecal immunochemical test accuracy may be adversely affected when samples are exposed to high temperatures. This study evaluated the effect of two sample collection buffer formulations (OC-Sensor, Eiken) and storage temperatures on faecal haemoglobin readings. Methods Faecal immunochemical test samples returned in a screening programme and with ≥10 µg Hb/g faeces in either the original or new formulation haemoglobin stabilizing buffer were stored in the freezer, refrigerator, or at room temperature (22℃-24℃), and reanalysed after 1-14 days. Samples in the new buffer were also reanalysed after storage at 35℃ and 50℃. Results were expressed as percentage of the initial concentration, and the number of days that levels were maintained to at least 80% was calculated. Results Haemoglobin concentrations were maintained above 80% of their initial concentration with both freezer and refrigerator storage, regardless of buffer formulation or storage duration. Stability at room temperature was significantly better in the new buffer, with haemoglobin remaining above 80% for 20 days compared with six days in the original buffer. Storage at 35℃ or 50℃ in the new buffer maintained haemoglobin above 80% for eight and two days, respectively. Conclusion The new formulation buffer has enhanced haemoglobin stabilizing properties when samples are exposed to temperatures greater than 22℃.

Use of seeded exotic grasslands by wintering birds

USGS Publications Warehouse

George, Andrew D.; O'Connell, Timothy J.; Hickman, Karen R.; Leslie,, David M.

2013-01-01

Despite widespread population declines of North American grassland birds, effects of anthropogenic disturbance of wintering habitat of this guild remain poorly understood. We compared avian abundance and habitat structure in fields planted by the exotic grass Old World bluestem (Bothriochloa ischaemum; OWB) to that in native mixed-grass prairie. During winters of 2007-2008 and 2008-2009, we conducted bird and vegetation surveys in six native grass and six OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. We recorded 24 species of wintering birds in native fields and 14 species in OWB monocultures. While vegetation structure was similar between field types, abundance of short-eared owls (Asio flammeus), northern harriers (Circus cyaneus) and Smith's longspurs (Calcarius pictus) was higher in OWB fields during at least one year. The use of OWB fields by multiple species occupying different trophic positions suggested that vegetation structure of OWB can meet habitat requirements of some wintering birds, but there is insufficient evidence to determine if it provides superior conditions to native grasses.

Longleaf Pine Ground-Layer Vegetation in Francis Marion National Forest: Reintroduction, Restoration, and Vegetation Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glitzenstein, J.; Streng, D.; Wade, D.

2001-01-01

Study represents significant progress in understanding of compositional gradients in longleaf pine plant communities of Central South Carolina. Study shows the importance of water table depths as a controlling variable with vegetation patterns in the field and similar effects in a garden experiment. Grass planting study suggests that observed field distributions of dormant pine savannah grasses derive from complex interactive effects of fire history, hydrology and light environments. Use of regional longleaf data set to identify candidate species for introduction also appears to be a pioneering effort.

Effects of liquid chromatography mobile phases and buffer salts on phosphorus inductively coupled plasma atomic emission and mass spectrometries utilizing ultrasonic nebulization and membrane desolvation.

PubMed

Carr, John E; Kwok, Kaho; Webster, Gregory K; Carnahan, Jon W

2006-01-23

Atomic spectrometry, specifically inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) show promise for heteroatom-based detection of pharmaceutical compounds. The combination of ultrasonic nebulization (USN) with membrane desolvation (MD) greatly enhances detection limits with these approaches. Because pharmaceutical analyses often incorporate liquid chromatography, the study herein was performed to examine the effects of solvent composition on the analytical behaviors of these approaches. The target analyte was phosphorus, introduced as phosphomycin. AES response was examined at the 253.7 nm atom line and mass 31 ions were monitored for the MS experiments. With pure aqueous solutions, detection limits of 5 ppb (0.5 ng in 0.1 mL injection volumes) were obtained with ICP-MS. The ICP-AES detection limit was 150 ppb. Solvent compositions were varied from 0 to 80% organic (acetonitrile and methanol) with nine buffers at concentrations typically used in liquid chromatography. In general, solvents and buffers had statistically significant, albeit small, effects on ICP-AES sensitivities. A few exceptions occurred in cases where typical liquid chromatography buffer concentrations produced higher mass loadings on the plasma. Indications are that isocratic separations can be reliably performed. Within reasonable accuracy tolerances, it appears that gradient chromatography can be performed without the need for signal response normalization. Organic solvent and buffer effects were more significant with ICP-MS. Sensitivities varied significantly with different buffers and organic solvent content. In these cases, gradient chromatography will require careful analytical calibration as solvent and buffer content is varied. However, for most buffer and solvent combinations, signal and detection limits are only moderately affected. Isocratic separations and detection are feasible.

Pulse-drought atop press-drought: unexpected plant responses and implications for dryland ecosystems.

PubMed

Hoover, David L; Duniway, Michael C; Belnap, Jayne

2015-12-01

In drylands, climate change is predicted to cause chronic reductions in water availability (press-droughts) through reduced precipitation and increased temperatures as well as increase the frequency and intensity of short-term extreme droughts (pulse-droughts). These changes in precipitation patterns may have profound ecosystem effects, depending on the sensitivities of the dominant plant functional types (PFTs). Here we present the responses of four Colorado Plateau PFTs to an experimentally imposed, 4-year, press-drought during which a natural pulse-drought occurred. Our objectives were to (1) identify the drought sensitivities of the PFTs, (2) assess the additive effects of the press- and pulse-drought, and (3) examine the interactive effects of soils and drought. Our results revealed that the C3 grasses were the most sensitive PFT to drought, the C3 shrubs were the most resistant, and the C4 grasses and shrubs had intermediate drought sensitivities. Although we expected the C3 grasses would have the greatest response to drought, the higher resistance of C3 shrubs relative to the C4 shrubs was contrary to our predictions based on the higher water use efficiency of C4 photosynthesis. Also, the additive effects of press- and pulse-droughts caused high morality in C3 grasses, which has large ecological and economic ramifications for this region. Furthermore, despite predictions based on the inverse texture hypothesis, we observed no interactive effects of soils with the drought treatment on cover or mortality. These results suggest that plant responses to droughts in drylands may differ from expectations and have large ecological effects if press- and pulse-droughts push species beyond physiological and mortality thresholds.

Pulse-drought atop press-drought: unexpected plant responses and implications for dryland ecosystems

USGS Publications Warehouse

Hoover, David L.; Duniway, Michael C.; Belnap, Jayne

2015-01-01

In drylands, climate change is predicted to cause chronic reductions in water availability (press-droughts) through reduced precipitation and increased temperatures as well as increase the frequency and intensity of short-term extreme droughts (pulse-droughts). These changes in precipitation patterns may have profound ecosystem effects, depending on the sensitivities of the dominant plant functional types (PFTs). Here we present the responses of four Colorado Plateau PFTs to an experimentally imposed, 4-year, press-drought during which a natural pulse-drought occurred. Our objectives were to (1) identify the drought sensitivities of the PFTs, (2) assess the additive effects of the press- and pulse-drought, and (3) examine the interactive effects of soils and drought. Our results revealed that the C3 grasses were the most sensitive PFT to drought, the C3shrubs were the most resistant, and the C4 grasses and shrubs had intermediate drought sensitivities. Although we expected the C3 grasses would have the greatest response to drought, the higher resistance of C3 shrubs relative to the C4 shrubs was contrary to our predictions based on the higher water use efficiency of C4 photosynthesis. Also, the additive effects of press- and pulse-droughts caused high morality in C3 grasses, which has large ecological and economic ramifications for this region. Furthermore, despite predictions based on the inverse texture hypothesis, we observed no interactive effects of soils with the drought treatment on cover or mortality. These results suggest that plant responses to droughts in drylands may differ from expectations and have large ecological effects if press- and pulse-droughts push species beyond physiological and mortality thresholds.

Direct effects of soil amendments on field emergence and growth of the invasive annual grass Bromus tectorum L. and the native perennial grass Hilaria jamesii (Torr.) Benth

USGS Publications Warehouse

Newingham, B.A.; Belnap, J.

2006-01-01

Bromus tectorum L. is a non-native, annual grass that has invaded western North America. In SE Utah, B. tectorum generally occurs in grasslands dominated by the native perennial grass, Hilaria jamesii (Torr.) Benth. and rarely where the natives Stipa hymenoides Roem. and Schult. and S. comata Trin. & Rupr. are dominant. This patchy invasion is likely due to differences in soil chemistry. Previous laboratory experiments investigated using soil amendments that would allow B. tectorum to germinate but would reduce B. tectorum emergence without affecting H. jamesii. For this study we selected the most successful treatments (CaCl2, MgCl2, NaCl and zeolite) from a previous laboratory study and applied them in the field in two different years at B. tectorum-dominated field sites. All amendments except the lowest level of CaCl2 and zeolite negatively affected B. tectorum emergence and/or biomass. No amendments negatively affected the biomass of H. jamesii but NaCl reduced emergence. Amendment effectiveness depended on year of application and the length of time since application. The medium concentration of zeolite had the strongest negative effect on B. tectorum with little effect on H. jamesii. We conducted a laboratory experiment to determine why zeolite was effective and found it released large amounts of Na+, adsorbed Ca2+, and increased Zn2+, Fe2+, Mn2+, Cu2+, exchangeable Mg2+, exchangeable K, and NH 4+ in the soil. Our results suggest several possible amendments to control B. tectorum. However, variability in effectiveness due to abiotic factors such as precipitation and soil type must be accounted for when establishing management plans. ?? Springer 2006.

Final Environmental Assessment For Wing Infrastructure Development Outlook (WINDO) Davis-Monthan Air Force Base, Tucson, Arizona

DTIC Science & Technology

2005-06-01

rothrockii Grama grass Bouteloua californica Grama grass Bouteloua radicosa Grama grass Bouteloua parryi Grama grass Bouteloua barbata Grama grass...with agave and columnar cacti present as food plants. May Occur Mammal Myotis velifer Cave myotis SC Desertscrub of creosote, brittlebush

50 CFR 21.52 - Public health control order for resident Canada geese.

Code of Federal Regulations, 2011 CFR

2011-10-01

... repellants, (G) Cervical dislocation, and (H) CO2 asphyxiation. (ii) Birds caught live may be euthanized or... lomatium, Contra Costa goldfields, Hoover's spurge, fleshy owl's clover, Colusa grass, hairy Orcutt grass, Solano grass, Greene's tuctoria, Sacramento Valley Orcutt grass, San Joaquin Valley Orcutt grass, slender...

75 FR 35801 - Notice of Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-23

....05 ppm; grass, hay at 0.05 ppm; and grass, forage at 1.5 ppm. An enforcement method for plants has...; sorghum, stover at 0.35 ppm; grass, hay at 2.5 ppm; and grass, forage at 10 ppm. The analytical method is... on sorghum, grain at 0.2 ppm; grass, hay at 5.0 ppm; and grass, forage at 18 ppm. Since bromoxynil...

Native Grasses as a Management Alternative on Vegetated Closure Caps

NASA Astrophysics Data System (ADS)

Kwit, Charles; Collins, Beverly

2008-06-01

Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainable alternative to turf grass communities. To determine if oldfield vegetation can establish on caps, we (1) compared establishment of a dominant oldfield grass and a commercial turf grass under different combinations of new closure cap management: spring or summer planting and presence or absence of amendments to alleviate drought (watering, mulch) or increase soil fertility (fertilizer, lime, a nitrogen-fixing legume); (2) surveyed existing caps to determine if oldfield species establish naturally; and (3) performed a greenhouse experiment to compare growth of two native grasses under low and amended (added water, soil nutrients) conditions. Both the commercial grass and oldfield species established under new cap conditions; fertilizer, water, and mulch improved vegetation establishment in spring or summer, but legumes decreased grass cover. In the greenhouse, both native grasses grew best with amendments; however, substantial stem and root length were obtained with no fertilizer and only once-weekly watering. Existing vegetated caps supported planted grasses and naturally established oldfield species. Overall, the results indicate native grasses can establish on new caps and oldfields can serve as a management model; further work is needed to determine the management strategy to maintain herbaceous vegetation and slow woody species invasion.

Treatment with grass allergen peptides improves symptoms of grass pollen-induced allergic rhinoconjunctivitis.

PubMed

Ellis, Anne K; Frankish, Charles W; O'Hehir, Robyn E; Armstrong, Kristen; Steacy, Lisa; Larché, Mark; Hafner, Roderick P

2017-08-01

Synthetic peptide immunoregulatory epitopes are a new class of immunotherapy to treat allergic rhinoconjunctivitis (ARC). Grass allergen peptides, comprising 7 synthetic T-cell epitopes derived from Cyn d 1, Lol p 5, Dac g 5, Hol l 5, and Phl p 5, is investigated for treatment of grass pollen-induced ARC. We sought to evaluate the efficacy, safety, and tolerability of intradermally administered grass allergen peptides. A multicenter, randomized, double-blind, placebo-controlled study evaluated 3 regimens of grass allergen peptides versus placebo in patients with grass pollen-induced allergy (18-65 years). After a 4-day baseline challenge to rye grass in the environmental exposure unit (EEU), subjects were randomized to receive grass allergen peptides at 6 nmol at 2-week intervals for a total of 8 doses (8x6Q2W), grass allergen peptides at 12 nmol at 4-week intervals for a total of 4 doses (4x12Q4W), or grass allergen peptides at 12 nmol at 2-week intervals for a total of 8 doses (8x12Q2W) or placebo and treated before the grass pollen season. The primary efficacy end point was change from baseline in total rhinoconjunctivitis symptom score across days 2 to 4 of a 4-day posttreatment challenge (PTC) in the EEU after the grass pollen season. Secondary efficacy end points and safety were also assessed. Two hundred eighty-two subjects were randomized. Significantly greater improvement (reduction of total rhinoconjunctivitis symptom score from baseline to PTC) occurred across days 2 to 4 with grass allergen peptide 8x6Q2W versus placebo (-5.4 vs -3.8, respectively; P = .0346). Greater improvement at PTC also occurred for grass allergen peptide 8x6Q2W versus placebo (P = .0403) in patients with more symptomatic ARC. No safety signals were detected. Grass allergen peptide 8x6Q2W significantly improved ARC symptoms after rye grass allergen challenge in an EEU with an acceptable safety profile. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

The effect of respiration buffer composition on mitochondrial metabolism and function.

PubMed

Wollenman, Lucas C; Vander Ploeg, Matthew R; Miller, Mackinzie L; Zhang, Yizhu; Bazil, Jason N

2017-01-01

Functional studies on isolated mitochondria critically rely on the right choice of respiration buffer. Differences in buffer composition can lead to dramatically different respiration rates leading to difficulties in comparing prior studies. The ideal buffer facilities high ADP-stimulated respiratory rates and minimizes substrate transport effects so that the ability to distinguish between various treatments and conditions is maximal. In this study, we analyzed a variety of respiration buffers and substrate combinations to determine the optimal conditions to support mitochondrial function through ADP-stimulated respiration and uncoupled respiration using FCCP. The buffers consisted of a standard KCl based buffer (B1) and three modified buffers with chloride replaced by the K-lactobionate, sucrose, and the antioxidant taurine (B2) or K-gluconate (B3). The fourth buffer (B4) was identical to B2 except that K-lactobionate was replaced with K-gluconate. The substrate combinations consisted of metabolites that utilize different pathways of mitochondrial metabolism. To test mitochondrial function, we used isolated cardiac guinea pig mitochondria and measured oxygen consumption for three respiratory states using an Oroboros Oxygraph-2k. These states were the leak state (energized mitochondria in the absence of adenylates), ADP-stimulated state (energized mitochondria in the presence of saturating ADP concentrations), and uncoupled state (energized mitochondria in the presence of FCCP). On average across all substrate combinations, buffers B2, B3, and B4 had an increase of 16%, 26%, and 35% for the leak state, ADP-simulated state, and uncoupled state, respectively, relative to rates using B1. The common feature distinguishing these buffers from B1 is the notable lack of high chloride concentrations. Based on the respiratory rate metrics obtained with the substrate combinations, we conclude that the adenine nucleotide translocase, the dicarboxylate carrier, and the alpha-ketoglutarate exchanger are partially inhibited by chloride. Therefore, when the goal is to maximize ADP-stimulated respiration, buffers containing K-lactobionate or K-gluconate are superior choices compared to the standard KCl-based buffers.

The effect of respiration buffer composition on mitochondrial metabolism and function

PubMed Central

Wollenman, Lucas C.; Vander Ploeg, Matthew R.; Miller, Mackinzie L.; Zhang, Yizhu

2017-01-01

Functional studies on isolated mitochondria critically rely on the right choice of respiration buffer. Differences in buffer composition can lead to dramatically different respiration rates leading to difficulties in comparing prior studies. The ideal buffer facilities high ADP-stimulated respiratory rates and minimizes substrate transport effects so that the ability to distinguish between various treatments and conditions is maximal. In this study, we analyzed a variety of respiration buffers and substrate combinations to determine the optimal conditions to support mitochondrial function through ADP-stimulated respiration and uncoupled respiration using FCCP. The buffers consisted of a standard KCl based buffer (B1) and three modified buffers with chloride replaced by the K-lactobionate, sucrose, and the antioxidant taurine (B2) or K-gluconate (B3). The fourth buffer (B4) was identical to B2 except that K-lactobionate was replaced with K-gluconate. The substrate combinations consisted of metabolites that utilize different pathways of mitochondrial metabolism. To test mitochondrial function, we used isolated cardiac guinea pig mitochondria and measured oxygen consumption for three respiratory states using an Oroboros Oxygraph-2k. These states were the leak state (energized mitochondria in the absence of adenylates), ADP-stimulated state (energized mitochondria in the presence of saturating ADP concentrations), and uncoupled state (energized mitochondria in the presence of FCCP). On average across all substrate combinations, buffers B2, B3, and B4 had an increase of 16%, 26%, and 35% for the leak state, ADP-simulated state, and uncoupled state, respectively, relative to rates using B1. The common feature distinguishing these buffers from B1 is the notable lack of high chloride concentrations. Based on the respiratory rate metrics obtained with the substrate combinations, we conclude that the adenine nucleotide translocase, the dicarboxylate carrier, and the alpha-ketoglutarate exchanger are partially inhibited by chloride. Therefore, when the goal is to maximize ADP-stimulated respiration, buffers containing K-lactobionate or K-gluconate are superior choices compared to the standard KCl-based buffers. PMID:29091971

What Drives the Occurrence of the Melioidosis Bacterium Burkholderia pseudomallei in Domestic Gardens?

PubMed Central

Kaestli, Mirjam; Harrington, Glenda; Mayo, Mark; Chatfield, Mark D.; Harrington, Ian; Hill, Audrey; Munksgaard, Niels; Gibb, Karen; Currie, Bart J.

2015-01-01

Melioidosis is an often fatal infectious disease affecting humans and animals in tropical regions and is caused by the saprophytic environmental bacterium Burkholderia pseudomallei. Domestic gardens are not only a common source of exposure to soil and thus to B. pseudomallei, but they also have been found to contain more B. pseudomallei than other environments. In this study we addressed whether anthropogenic manipulations common to gardens such as irrigation or fertilizers change the occurrence of B. pseudomallei. We conducted a soil microcosm experiment with a range of fertilizers and soil types as well as a longitudinal interventional study over three years on an experimental fertilized field site in an area naturally positive for B. pseudomallei. Irrigation was the only consistent treatment to increase B. pseudomallei occurrence over time. The effects of fertilizers upon these bacteria depended on soil texture, physicochemical soil properties and biotic factors. Nitrates and urea increased B. pseudomallei load in sand while phosphates had a positive effect in clay. The high buffering and cation exchange capacities of organic material found in a commercial potting mix led to a marked increase in soil salinity with no survival of B. pseudomallei after four weeks in the potting mix sampled. Imported grasses were also associated with B. pseudomallei occurrence in a multivariate model. With increasing population density in endemic areas these findings inform the identification of areas in the anthropogenic environment with increased risk of exposure to B. pseudomallei. PMID:25803046

Rapid sequencing of the bamboo mitochondrial genome using Illumina technology and parallel episodic evolution of organelle genomes in grasses.

PubMed

Ma, Peng-Fei; Guo, Zhen-Hua; Li, De-Zhu

2012-01-01

Compared to their counterparts in animals, the mitochondrial (mt) genomes of angiosperms exhibit a number of unique features. However, unravelling their evolution is hindered by the few completed genomes, of which are essentially Sanger sequenced. While next-generation sequencing technologies have revolutionized chloroplast genome sequencing, they are just beginning to be applied to angiosperm mt genomes. Chloroplast genomes of grasses (Poaceae) have undergone episodic evolution and the evolutionary rate was suggested to be correlated between chloroplast and mt genomes in Poaceae. It is interesting to investigate whether correlated rate change also occurred in grass mt genomes as expected under lineage effects. A time-calibrated phylogenetic tree is needed to examine rate change. We determined a largely completed mt genome from a bamboo, Ferrocalamus rimosivaginus (Poaceae), through Illumina sequencing of total DNA. With combination of de novo and reference-guided assembly, 39.5-fold coverage Illumina reads were finally assembled into scaffolds totalling 432,839 bp. The assembled genome contains nearly the same genes as the completed mt genomes in Poaceae. For examining evolutionary rate in grass mt genomes, we reconstructed a phylogenetic tree including 22 taxa based on 31 mt genes. The topology of the well-resolved tree was almost identical to that inferred from chloroplast genome with only minor difference. The inconsistency possibly derived from long branch attraction in mtDNA tree. By calculating absolute substitution rates, we found significant rate change (∼4-fold) in mt genome before and after the diversification of Poaceae both in synonymous and nonsynonymous terms. Furthermore, the rate change was correlated with that of chloroplast genomes in grasses. Our result demonstrates that it is a rapid and efficient approach to obtain angiosperm mt genome sequences using Illumina sequencing technology. The parallel episodic evolution of mt and chloroplast genomes in grasses is consistent with lineage effects.

Performance and carcass characteristics of lambs fed diets with increasing levels of Mimosa tenuiflora (Willd.) hay replacing Buffel grass hay.

PubMed

Bandeira, Paulo André Vidal; Filho, José Morais Pereira; de Azevêdo Silva, Aderbal Marcos; Cezar, Marcílio Fontes; Bakke, Olaf Andreas; Silva, Uilma Laurentino; Borburema, Jucileide Barbosa; Bezerra, Leilson Rocha

2017-06-01

This study evaluated the performance and carcass characteristics of lambs fed diets with increasing levels of Mimosa tenuiflora (Willd.) hay replacing Buffel grass (Cenchrus ciliaris). Twenty-eight Santa Inês male lambs with an average body weight (BW) of 20.3 ± 1.49 kg(mean ± SD) were allocated in individual stalls and distributed in a completely random design with four treatments (0, 20, 40, and 60 g/100 g total DM M. tenuiflora hay replacing Buffel grass hay in diet) with seven replications. M. tenuiflora hay at the level of 20% dry matter (DM) total replacing Buffel grass hay increased final weight (P = 0.006), total weight gain (P < 0.001), average daily weight gain (ADWG; P < 0.001), DM intake (P < 0.001), and feed efficiency (P < 0.001). Intake of crude protein, NDF ap , ADF ap , ash, ether extract, total and non-fibrous carbohydrates, and total digestible nutrients presented a positive quadratic effect with M. tenuiflora hay replacing Buffel grass hay and 40 g/100 g total DM level presented greater intake. There were positive quadratic effects by M. tenuiflora hay inclusion at 20 g/100 g total DM level on slaughtering weight (P = 0.005), hot carcass weight (P = 0.002), cold carcass weight (P = 0.002), empty body weight (P = 0.001), hot carcass yield (P = 0.002), cold carcass yield (P = 0.003), and increase linear on biological yield (P = 0.003). There was no influence on cooling weight loss (P = 0.284). M. tenuiflora hay may be included in lamb diets at amounts up to 20 g/100 g total DM substitution of Buffel grass hay because increase in the nutrients intake, growth performance, and carcass characteristics.

Rapid Sequencing of the Bamboo Mitochondrial Genome Using Illumina Technology and Parallel Episodic Evolution of Organelle Genomes in Grasses

PubMed Central

Ma, Peng-Fei; Guo, Zhen-Hua; Li, De-Zhu

2012-01-01

Background Compared to their counterparts in animals, the mitochondrial (mt) genomes of angiosperms exhibit a number of unique features. However, unravelling their evolution is hindered by the few completed genomes, of which are essentially Sanger sequenced. While next-generation sequencing technologies have revolutionized chloroplast genome sequencing, they are just beginning to be applied to angiosperm mt genomes. Chloroplast genomes of grasses (Poaceae) have undergone episodic evolution and the evolutionary rate was suggested to be correlated between chloroplast and mt genomes in Poaceae. It is interesting to investigate whether correlated rate change also occurred in grass mt genomes as expected under lineage effects. A time-calibrated phylogenetic tree is needed to examine rate change. Methodology/Principal Findings We determined a largely completed mt genome from a bamboo, Ferrocalamus rimosivaginus (Poaceae), through Illumina sequencing of total DNA. With combination of de novo and reference-guided assembly, 39.5-fold coverage Illumina reads were finally assembled into scaffolds totalling 432,839 bp. The assembled genome contains nearly the same genes as the completed mt genomes in Poaceae. For examining evolutionary rate in grass mt genomes, we reconstructed a phylogenetic tree including 22 taxa based on 31 mt genes. The topology of the well-resolved tree was almost identical to that inferred from chloroplast genome with only minor difference. The inconsistency possibly derived from long branch attraction in mtDNA tree. By calculating absolute substitution rates, we found significant rate change (∼4-fold) in mt genome before and after the diversification of Poaceae both in synonymous and nonsynonymous terms. Furthermore, the rate change was correlated with that of chloroplast genomes in grasses. Conclusions/Significance Our result demonstrates that it is a rapid and efficient approach to obtain angiosperm mt genome sequences using Illumina sequencing technology. The parallel episodic evolution of mt and chloroplast genomes in grasses is consistent with lineage effects. PMID:22272330

The negative effects of cadmium on Bermuda grass growth might be offset by submergence.

PubMed

Tan, Shuduan; Huang, Huang; Zhu, Mingyong; Zhang, Kerong; Xu, Huaqin; Wang, Zhi; Wu, Xiaoling; Zhang, Quanfa

2013-10-01

Revegetation in the water-level-fluctuation zone (WLFZ) could stabilize riverbanks, maintain local biodiversity, and improve reservoir water quality in the Three Gorges Reservoir Region (TGRR). However, submergence and cadmium (Cd) may seriously affect the survival of transplantations. Bermuda grass (Cynodon dactylon) is a stoloniferous and rhizomatous prostrate weed displaying high growth rate. A previous study has demonstrated that Bermuda grass can tolerate deep submergence and Cd stress, respectively. In the present study, we further analyzed physiological responses of Bermuda grass induced by Cd-and-submergence stress. The ultimate goal was to explore the possibility of using Bermuda grass for revegetation in the WLFZ of China's TGRR and other riparian areas. The Cd-and-submergence-treated plants had higher malondialdehyde contents and peroxidase than control, and both increased with the Cd concentration increase. All treated plants catalase activity increased with the experimental duration increases, and their superoxide dismutase also gradually increased with the Cd concentration from 1 day to 15 days. Total biomass of the same Cd-and-submergence plants increased along the experimental duration as well. Plants exposed to Cd-and-submergence stress showed shoot elongation. The heights of all treated plants were taller than those of the control. Leaf chlorophyll contents, maximum leaf length, and soluble sugars contents of all the Cd-and-submergence-treated plants were more than those of the untreated control. Although Cd inhibits plants growth, decreases chlorophyll and biomass content, and with the submergence induced the leaf and shoot elongation, more part of the Cd-and-submergence stress plants appeared in the air, exhibited fast growth with maintenance of leaf color, which guaranteed the plants' photosynthesis, and ensured the total biomass and carbohydrate sustainability, further promoting Cd-and-submergence tolerance. The results imply that the negative effects of cadmium on Bermuda grass growth might be offset by submergence.

[Allelopathic effects of extracts from tuberous roots of Aconitum carmichaeli on three pasture grasses].

PubMed

Jiao, Yu-jie; Wang, Ya-qi; Yuan, Ling

2015-11-01

The tuberous roots of Aconitum carmichaeli are largely used in traditional Chinese medicine and widely grown in Jiangyou, Sichuan, China. During the growth process, this medicinal plant releases a large amount of allelochemicals into soil, which retard the growth and development of near and late crops. Therefore, a pure culture experiment was thus carried out by seed soaking to study the allelopathic effects of extracts from tuberous roots of A. carmichaeli (ETR) on the seed germination and young seedling growth of Lolium perenne, Trifolium repens, and Medicago sativa, the late pasture grasses after cultivation of A. carmichaeli. The results showed that three pasture grasses varied significantly in seed germination and young seedling growth in response to ETR concentrations. Seed germination of M. sativa was stimulated by low ERT concentration (0.01 x g(-1)), while all of pasture grass seeds germinated poorly in solution with 1.00 g x L(-1). Seed soaking with 1.00 g x L(-1) also inhibited significantly the growth of pasture young seedlings, with M. sativa showing the highest seedling height reduction of 42.05% in seeding height, followed by T. repens (40.21%) and L. perenne with about 11%. Cultivation of L. perenne could thus be beneficial to increase whole land productivity in A. carmichaeli-pasture grass cropping systems. In addition, hydrolysis of protein, starch, and inositol phosphates was blocked and free amino acids, soluble sugars and phosphorus were decreased in seeds by seed soaking with ETR, which could be one of the reason for the inhibition of seed germination. There was a significant reduction in root vigor, nitrate reductase, and chlorophyll after the seed treatment with ETR, indicating the suppression of nutrient uptake, nitrate assimilation, and photosynthesis by allelopathic chemicals in ETR, which could lead to the slow growth rate of pasture grass seedlings.

Differential effects of lichens, mosses and grasses on respiration and nitrogen mineralization in soils of the New Jersey Pinelands.

PubMed

Sedia, Ekaterina G; Ehrenfeld, Joan G

2005-06-01

In the New Jersey Pinelands, severely disturbed areas often do not undergo a rapid succession to forest; rather, a patchy cover of lichens, mosses and grasses persists for decades. We hypothesized that these plant covers affect soil microbial processes in different ways, and that these effects may alter the successional dynamics of the patches. We predicted that the moss and grass covers stimulate soil microbial activity, whereas lichens inhibit it, which may in turn inhibit succession. We collected soil cores from beneath each type of cover plus bare soil within two types of highly disturbed areas--sites subjected to hot wildfires, and areas mined for sand. Organic matter (OM) content, soil respiration and potential N mineralization were measured in the cores. Soils under mosses were similar to those under grasses; they accumulated more OM and produced more mineral N, predominantly in the form of ammonium, than either the bare soils or the soils beneath lichens. Mineralization under lichens, like that of the bare soils but unlike the soils beneath mosses or grasses, was dominated by net nitrification. These patterns were reproduced in experimentally transplanted moss and lichen mats. Mosses appear to create high-nutrient microsites via high rates of OM accumulation and production of ammonium, whereas lichens maintain low-nutrient patches similar to bare soil via low OM accumulation rates and production of mineral N predominantly in the mobile nitrate form. These differences in soil properties may explain the lack of vascular plant invasion in lichen mats, in contrast to the moss-dominated areas.

Maternal buffering beyond glucocorticoids: impact of early life stress on corticolimbic circuits that control infant responses to novelty

PubMed Central

Howell, Brittany R.; McMurray, Matthew S.; Guzman, Dora B.; Nair, Govind; Shi, Yundi; McCormack, Kai M.; Hu, Xiaoping; Styner, Martin A.; Sanchez, Mar M.

2017-01-01

Maternal presence has a potent buffering effect on infant fear and stress responses in primates. We previously reported that maternal presence is not effective in buffering the endocrine stress response in infant rhesus monkeys reared by maltreating mothers. We have also reported that maltreating mothers show low maternal responsiveness and permissiveness/secure-base behavior. Although still not understood, it is possible that this maternal buffering effect is mediated, at least partially, through deactivation of amygdala response circuits when mothers are present. Here we studied rhesus monkey infants that differed in the quality of early maternal care to investigate how this early experience modulated maternal buffering effects on behavioral responses to novelty during the weaning period. We also examined the relationship between these behavioral responses and structural connectivity in one of the underlying regulatory neural circuits: amygdala-prefrontal pathways. Our findings suggest that infant exploration in a novel situation is predicted by maternal responsiveness and structural integrity of amygdala-prefrontal white matter depending on maternal presence (positive relationships when mother is absent). These results provide evidence that maternal buffering of infant behavioral inhibition is dependent on the quality of maternal care and structural connectivity of neural pathways that are sensitive to early life stress. PMID:27295326

Riparian buffer strips as a multifunctional management tool in agricultural landscapes: introduction.

PubMed

Stutter, Marc I; Chardon, Wim J; Kronvang, Brian

2012-01-01

Catchment riparian areas are considered key zones to target mitigation measures aimed at interrupting the movement of diffuse substances from agricultural land to surface waters. Hence, unfertilized buffer strips have become a widely studied and implemented "edge of field" mitigation measure assumed to provide an effective physical barrier against nitrogen (N), phosphorus (P), and sediment transfer. To ease the legislative process, these buffers are often narrow mandatory strips along streams and rivers, across different riparian soil water conditions, between bordering land uses of differing pollution burdens, and without prescribed buffer management. It would be easy to criticize such regulation for not providing the opportunity for riparian ecosystems to maximize their provision for a wider range of ecosystem goods and services. The scientific basis for judging the best course of action in designing and placing buffers to enhance their multifunctionality has slowly increased over the last five years. This collection of papers aims to add to this body of knowledge by giving examples of studies related to riparian buffer management and assessment throughout Europe. This introductory paper summarizes discussion sessions and 13 selected papers from a workshop held in Ballater, UK, highlighting research on riparian buffers brought together under the EU COST Action 869 knowledge exchange program. The themes addressed are (i) evidence of catchment- to national-scale effectiveness, (ii) ecological functioning linking terrestrial and aquatic habitats, (iii) modeling tools for assessment of effectiveness and costs, and (iv) process understanding enabling management and manipulation to enhance pollutant retention in buffers. The combined understanding led us to consider four principle key questions to challenge buffer strip research and policy. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Intra- and Inter-personal Consequences of Protective Buffering among Cancer Patients and Caregivers

PubMed Central

Langer, Shelby L.; Brown, Jonathon D.; Syrjala, Karen L.

2009-01-01

BACKGROUND Protective buffering refers to hiding cancer-related thoughts and concerns from one’s spouse or partner. This study sought to examine the intra- and inter-personal consequences of protective buffering and motivations for such (desire to shield partner from distress, desire to shield self from distress). METHODS Eighty hematopoietic stem cell transplant patients and their spousal caregivers/ partners completed measures designed to assess protective buffering and relationship satisfaction at two time points: prior to the transplant (T1) and 50 days post-transplant (T2). Overall mental health was also assessed at T2. RESULTS There was moderate agreement between one dyad member’s reported buffering of his/ her partner, and the partner’s perception of the extent to which s/he felt buffered. Caregivers buffered patients more than patients buffered caregivers, especially at T2. The more participants buffered their partners at T2, and the more they felt buffered, the lower their concurrent relationship satisfaction and the poorer their mental health. The latter effect was particularly true for patients who buffered, and patients who felt buffered. With respect to motivations, patients who buffered primarily to protect their partner at T1 reported increases in relationship satisfaction over time, but when they did so at T2, their caregiver reported concurrent decreases in relationship satisfaction. CONCLUSIONS Protective buffering is costly, in that those who buffer and those who feel buffered report adverse psychosocial outcomes. In addition, buffering enacted by patients with an intention to help may prove counterproductive, ultimately hurting the object of such protection. PMID:19731352

How do earthworms, soil texture and plant composition affect infiltration along an experimental plant diversity gradient in grassland?

PubMed

Fischer, Christine; Roscher, Christiane; Jensen, Britta; Eisenhauer, Nico; Baade, Jussi; Attinger, Sabine; Scheu, Stefan; Weisser, Wolfgang W; Schumacher, Jens; Hildebrandt, Anke

2014-01-01

Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied. We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species) and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs). In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i) direct, probably by modifying the pore spectrum and (ii) indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms. Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications.

Fragmentation impairs the microclimate buffering effect of tropical forests.

PubMed

Ewers, Robert M; Banks-Leite, Cristina

2013-01-01

Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered microclimate conditions driven by edge effects, and extrapolate these results to the whole Atlantic Forest biome, one of the most disturbed biodiversity hotspots. To address these questions, we collected above and below ground temperature for a full year using temperature sensors placed in forest fragments of different sizes, and at different distances from the forest edge. In the Atlantic forests of Brazil, we found that the buffering effect of forests reduced maximum outside temperatures by one third or more at ground level within a forest, with the buffering effect being stronger below-ground than one metre above-ground. The temperature buffering effect of forests was, however, reduced near forest edges with the edge effect extending up to 20 m inside the forest. The heavily fragmented nature of the Brazilian Atlantic forest means that 12% of the remaining biome experiences altered microclimate conditions. Our results add further information about the extent of edge effects in the Atlantic Forest, and we suggest that maintaining a low perimeter-to-area ratio may be a judicious method for minimizing the amount of forest area that experiences altered microclimatic conditions in this ecosystem.

Fragmentation Impairs the Microclimate Buffering Effect of Tropical Forests

PubMed Central

Ewers, Robert M.; Banks-Leite, Cristina

2013-01-01

Background Tropical forest species are among the most sensitive to changing climatic conditions, and the forest they inhabit helps to buffer their microclimate from the variable climatic conditions outside the forest. However, habitat fragmentation and edge effects exposes vegetation to outside microclimatic conditions, thereby reducing the ability of the forest to buffer climatic variation. In this paper, we ask what proportion of forest in a fragmented ecosystem is impacted by altered microclimate conditions driven by edge effects, and extrapolate these results to the whole Atlantic Forest biome, one of the most disturbed biodiversity hotspots. To address these questions, we collected above and below ground temperature for a full year using temperature sensors placed in forest fragments of different sizes, and at different distances from the forest edge. Principal Findings In the Atlantic forests of Brazil, we found that the buffering effect of forests reduced maximum outside temperatures by one third or more at ground level within a forest, with the buffering effect being stronger below-ground than one metre above-ground. The temperature buffering effect of forests was, however, reduced near forest edges with the edge effect extending up to 20 m inside the forest. The heavily fragmented nature of the Brazilian Atlantic forest means that 12% of the remaining biome experiences altered microclimate conditions. Conclusions Our results add further information about the extent of edge effects in the Atlantic Forest, and we suggest that maintaining a low perimeter-to-area ratio may be a judicious method for minimizing the amount of forest area that experiences altered microclimatic conditions in this ecosystem. PMID:23483976

AlGaSb Buffer Layers for Sb-Based Transistors

DTIC Science & Technology

2010-01-01

transistor ( HEMT ), molecular beam epitaxy (MBE), field-effect transistor (FET), buffer layer INTRODUCTION High-electron-mobility transistors ( HEMTs ) with InAs...monolayers/s. The use of thinner buffer layers reduces molecular beam epitaxial growth time and source consumption. The buffer layers also exhibit...source. In addition, some of the flux from an Sb cell in a molecular beam epitaxy (MBE) system will deposit near the mouth of the cell, eventually

Quantitative and qualitative optimization of allergen extraction from peanut and selected tree nuts. Part 2. Optimization of buffer and ionic strength using a full factorial experimental design.

PubMed

L'Hocine, Lamia; Pitre, Mélanie

2016-03-01

A full factorial design was used to assess the single and interactive effects of three non-denaturing aqueous (phosphate, borate, and carbonate) buffers at various ionic strengths (I) on allergen extractability from and immunoglobulin E (IgE) immunoreactivity of peanut, almond, hazelnut, and pistachio. The results indicated that the type and ionic strength of the buffer had different effects on protein recovery from the nuts under study. Substantial differences in protein profiles, abundance, and IgE-binding intensity with different combinations of pH and ionic strength were found. A significant interaction between pH and ionic strength was observed for pistachio and almond. The optimal buffer system conditions, which maximized the IgE-binding efficiency of allergens and provided satisfactory to superior protein recovery yield and profiles, were carbonate buffer at an ionic strength of I=0.075 for peanut, carbonate buffer at I=0.15 for almond, phosphate buffer at I=0.5 for hazelnut, and borate at I=0.15 for pistachio. The buffer type and its ionic strength could be manipulated to achieve the selective solubility of desired allergens. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Protocol for buffer space negotiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nessett, D.

There are at least two ways to manage the buffer memory of a communications node. On etechnique veiws the buffer as a single resource that is to be reserved and released as a unit for a particular communication transaction. A more common approach treats the node's buffer space as a collection of resources (e.g., bytes, words, packet slots) capable of being allocated among multiple concurrent conversations. To achieve buffer space multiplexing, some sort of negotiation for buffer space must take place between source and sink nodes before a transaction can commence. Results are presented which indicate that, for an applicationmore » involving a CSMA broadcast network, buffer space multiplexing offers better performance than buffer reservation. To achieve this improvement, a simple protocol is presented that features flow-control information traveling both from source to sink as well as from sink to source. It is argued that this bidirectionality allows the sink to allocate buffer space among its active communication paths more effectively. 13 figures.« less

Interactions with parents and friends among chronically ill children: examining social networks.

PubMed

Herzer, Michele; Umfress, Kris; Aljadeff, Gabriel; Ghai, Kanika; Zakowski, Sandra G

2009-12-01

Children with medical conditions often experience a combination of positive and negative social interactions with parents and friends. Adult research examining cross-domain buffering effects has documented that supportive social ties can make up for shortcomings in other social relationships. This study examined whether negative effects of strained relationships with loved ones can be buffered when children feel supported by individuals in different support networks (i.e., cross-domain buffering effects). Children with Type I diabetes (n = 56), chronic asthma (n = 54), and cystic fibrosis (n = 17) completed questionnaires during an outpatient hospital visit that assessed perceptions of support and strain from parents and friends, quality of life, self-concept, and emotional/behavioral difficulties. Parental strain was conceptualized as parental overprotection and parental rejection. Hierarchical regression analyses showed that friend support buffered the adverse effects of parental strain on child quality of life, self-concept, and emotional/behavioral difficulties. Interestingly, parental support did not buffer the negative effects of experiencing strained relationships with friends; only main effects on outcome were found. These findings partially support our hypotheses of cross-domain buffering. In this study, friendships were a protective factor for children who experienced strained relationships with parents. In contrast, although parent support had a direct impact on child outcome, it did not make up for feeling rejected by friends. Because close relationships are often strained during medical stressors, findings underscore the importance of promoting social connectedness in chronically ill children to maximize opportunities for experiencing positive social relationships.

With a little help from my assistant: buffering the negative effects of emotional dissonance on dentist performance.

PubMed

Rodríguez-Sánchez, Alma M; Hakanen, Jari J; Perhoniemi, Riku; Salanova, Marisa

2013-10-01

In this study, we hypothesized that dentist' interpersonal resources (good cooperation with one's assistant) together with their personal resources (optimism) buffer the negative effects of emotional dissonance (a demand that occurs when there is a difference between felt and displayed emotions) on job performance (in-role and extra-role performance) over time. We carried out Hierarchical Regression Modeling on a sample of 1954 Finnish dentists who participated in a two-wave 4-year longitudinal study. Results showed that good cooperation with dental assistants buffered the negative effects of emotional dissonance on both in-role and extra-role performance among the dentists in the long term. However, unexpectedly, dentists' high optimism did not buffer their in-role nor extra-role performance over time under conditions of experiencing high emotional dissonance. We conclude that interpersonal job resources such as good cooperation with one's colleagues may buffer the negative effect of emotional dissonance on dentists' job performance even in the long term, whereas the role of personal resources (e.g., optimism) may be less important for maintaining high job performance under conditions of emotional dissonance. The study novelties include the test of the negative effects of emotional dissonance on long-term performance in dentistry and the identification of the job rather than personal resources as the buffers against the negative effects of emotional dissonance on long-term performance. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Grass competition suppresses savanna tree growth across multiple demographic stages.

PubMed

Riginos, Corinna

2009-02-01

Savanna ecosystems, defined by the codominance of trees and grasses, cover one-fifth of the world's land surface and are of great socioeconomic and biological importance. Yet, the fundamental question of how trees and grasses coexist to maintain the savanna state remains poorly understood. Many models have been put forward to explain tree-grass coexistence, but nearly all have assumed that grasses do not limit tree growth and demography beyond the sapling stage. This assumption, however, has rarely been tested. Here I show that grass can strongly suppress the growth of trees. I removed grass around trees of three size classes in an Acacia drepanolobium savanna in Laikipia, Kenya. For even the largest trees, grass removal led to a doubling in growth and a doubling in the probability of transitioning to the next size class over two years. These results suggest that grass competition in productive (nutrient-rich) savannas may limit tree growth as much as herbivory and fire (the main factors thought to determine tree demography within a rainfall region) and should be incorporated into savanna models if tree-grass coexistence and savanna dynamics are to be understood.

Effects on the equine colon ecosystem of grass silage and haylage diets after an abrupt change from hay.

PubMed

Muhonen, S; Julliand, V; Lindberg, J E; Bertilsson, J; Jansson, A

2009-07-01

The objective of this study was to investigate the effect of an abrupt change from grass hay (81% DM) to grass silage (36% DM) or grass haylage (55% DM), fed at similar DM intakes, and to compare the effects of silage and haylage on the composition and activities of the colon microflora. The forages were from the same swath harvested on the same day. Four adult colon-fistulated geldings were randomly assigned to diets in a crossover design. The study started with a preperiod when all 4 horses received the hay diet, followed by an abrupt feed change to the haylage diet for 2 horses and the silage diet for 2 horses. All 4 horses then had a new second preperiod of hay, followed by an abrupt feed change to the opposite haylage and silage diet. The periods were 21 d long, and the forage-only diets were supplemented with minerals and salt. The abrupt feed changes were made at 0800 h. Colon samples were taken before the abrupt feed change, 4 and 28 h after the feed change, and 8, 15, and 21 d after the feed change, all at 1200 h. Colon bacterial counts, VFA, pH, and DM concentrations were unchanged throughout the first 28 h after the abrupt feed change from hay to haylage and silage. Also, fecal pH and DM concentrations were unchanged during the first 28 h. During the weekly observations, colon lactobacilli counts increased (P = 0.023) in horses receiving the silage diet and were greater than on the haylage diet at 21 d. Streptococci counts decreased (P = 0.046) in horses receiving the haylage diet and were less than on the silage diet at 15 and 21 d. Total VFA concentrations and colon and fecal pH did not differ between diets and were unchanged throughout the weekly observations. The DM concentration of colon digesta and feces decreased (P = 0.030 and 0.049, respectively) on both diets during the weekly observations. The results suggest that in horses fed at the maintenance level of energy intake, an abrupt feed change from grass hay to grass silage or grass haylage from the same crop does not induce any major alterations in the colon ecosystem during the first 28 h. During the subsequent 3-wk period, colon and fecal DM decreased and there were alterations in the lactobacilli and streptococci bacterial counts. The changes in lactobacilli and streptococci counts need further investigation.