Exploring the Future of Fuel Loads in Tasmania, Australia: Shifts in Vegetation in Response to Changing Fire Weather, Productivity, and Fire Frequency

Directory of Open Access Journals (Sweden)

Rebecca Mary Bernadette Harris

2018-04-01

Full Text Available Changes to the frequency of fire due to management decisions and climate change have the potential to affect the flammability of vegetation, with long-term effects on the vegetation structure and composition. Frequent fire in some vegetation types can lead to transformational change beyond which the vegetation type is radically altered. Such feedbacks limit our ability to project fuel loads under future climatic conditions or to consider the ecological tradeoffs associated with management burns. We present a “pathway modelling” approach to consider multiple transitional pathways that may occur under different fire frequencies. The model combines spatial layers representing current and future fire danger, biomass, flammability, and sensitivity to fire to assess potential future fire activity. The layers are derived from a dynamically downscaled regional climate model, attributes from a regional vegetation map, and information about fuel characteristics. Fire frequency is demonstrated to be an important factor influencing flammability and availability to burn and therefore an important determinant of future fire activity. Regional shifts in vegetation type occur in response to frequent fire, as the rate of change differs across vegetation type. Fire-sensitive vegetation types move towards drier, more fire-adapted vegetation quickly, as they may be irreversibly impacted by even a single fire, and require very long recovery times. Understanding the interaction between climate change and fire is important to identify appropriate management regimes to sustain fire-sensitive communities and maintain the distribution of broad vegetation types across the landscape.

The shifting nature of vegetation controls on peak snowpack with varying slope and aspect

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Biederman, J. A.; Harpold, A. A.; Broxton, P. D.; Brooks, P. D.

2012-12-01

The controls on peak seasonal snowpack are known to shift between forested and open environments as well as with slope and aspect. Peak snowpack is predicted well by interception models under uniformly dense canopy, while topography, wind and radiation are strong predictors in open areas. However, many basins have complex mosaics of forest canopy and small gaps, where snowpack controls involve complex interactions among climate, topography and forest structure. In this presentation we use a new fully distributed tree-scale model to investigate vegetation controls on snowpack for a range of slope and aspect, and we evaluate the energy balance in forest canopy and gap environments. The model is informed by airborne LiDAR and ground-based observations of climate, vegetation and snowpack. It represents interception, snow distribution by wind, latent and sensible heat fluxes, and radiative fluxes above and below the canopy at a grid scale of 1 m square on an hourly time step. First, the model is minimally calibrated using continuous records of snow depth and snow water equivalent (SWE). Next, the model is evaluated using distributed observations at peak accumulation. Finally, the domain is synthetically altered to introduce ranges of slope and aspect. Northerly aspects accumulate greater peak SWE than southerly aspects (e.g. 275 mm vs. 250 mm at a slope of 28 %) but show lower spatial variability (e. g. CV = 0.14 vs. CV = 0.17 at slope of 28 %). On northerly aspects, most of the snowpack remains shaded by vegetation, whereas on southerly aspects the northern portions of gaps and southern forest edges receive direct insolation during late winter. This difference in net radiation makes peak SWE in forest gaps and adjacent forest edges more sensitive to topography than SWE in areas under dense canopy. Tree-scale modeling of snow dynamics over synthetic terrain offers extensive possibilities to test interactions among vegetation and topographic controls.

Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa

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Theo H.C. Mostert

2008-10-01

Full Text Available The Major Megetation Types (MVT and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN. The resulting classification was further refined with table-sorting procedures based on the Braun–Blanquet floristic–sociological approach of vegetation classification using MEGATAB. Eight MVT’s were identified and described as Eragrostis lehmanniana var. lehmanniana–Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum–Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum–Combretum molle Blouberg Mountain Bushveld, Adansonia digitata–Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis–Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon–Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida–Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora–Rhus chirendensis Soutpansberg Forest Vegetation.

Trend shifts in satellite-derived vegetation growth in Central Eurasia, 1982-2013.

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Xu, Hao-Jie; Wang, Xin-Ping; Yang, Tai-Bao

2017-02-01

Central Eurasian vegetation is critical for the regional ecological security and the global carbon cycle. However, climatic impacts on vegetation growth in Central Eurasia are uncertain. The reason for this uncertainty lies in the fact that the response of vegetation to climate change showed nonlinearity, seasonality and differences among plant functional types. Based on remotely sensed vegetation index and in-situ meteorological data for the years 1982-2013, in conjunction with the latest land cover type product, we analyzed how vegetation growth trend varied across different seasons and evaluated vegetation response to climate variables at regional, biome and pixel scales. We found a persistent increase in the growing season NDVI over Central Eurasia during 1982-1994, whereas this greening trend has stalled since the mid-1990s in response to increased water deficit. The stalled trend in the growing season NDVI was largely attributed by summer and autumn NDVI changes. Enhanced spring vegetation growth after 2002 was caused by rapid spring warming. The response of vegetation to climatic factors varied in different seasons. Precipitation was the main climate driver for the growing season and summer vegetation growth. Changes in temperature and precipitation during winter and spring controlled the spring vegetation growth. Autumn vegetation growth was mainly dependent on the vegetation growth in summer. We found diverse responses of different vegetation types to climate drivers in Central Eurasia. Forests were more responsive to temperature than to precipitation. Grassland and desert vegetation responded more strongly to precipitation than to temperature in summer but more strongly to temperature than to precipitation in spring. In addition, the growth of desert vegetation was more dependent on winter precipitation than that of grasslands. This study has important implications for improving the performance of terrestrial ecosystem models to predict future vegetation

Climate change-induced vegetation shifts lead to more ecological droughts despite projected rainfall increases in many global temperate drylands.

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Tietjen, Britta; Schlaepfer, Daniel R; Bradford, John B; Lauenroth, William K; Hall, Sonia A; Duniway, Michael C; Hochstrasser, Tamara; Jia, Gensuo; Munson, Seth M; Pyke, David A; Wilson, Scott D

2017-07-01

Drylands occur worldwide and are particularly vulnerable to climate change because dryland ecosystems depend directly on soil water availability that may become increasingly limited as temperatures rise. Climate change will both directly impact soil water availability and change plant biomass, with resulting indirect feedbacks on soil moisture. Thus, the net impact of direct and indirect climate change effects on soil moisture requires better understanding. We used the ecohydrological simulation model SOILWAT at sites from temperate dryland ecosystems around the globe to disentangle the contributions of direct climate change effects and of additional indirect, climate change-induced changes in vegetation on soil water availability. We simulated current and future climate conditions projected by 16 GCMs under RCP 4.5 and RCP 8.5 for the end of the century. We determined shifts in water availability due to climate change alone and due to combined changes of climate and the growth form and biomass of vegetation. Vegetation change will mostly exacerbate low soil water availability in regions already expected to suffer from negative direct impacts of climate change (with the two RCP scenarios giving us qualitatively similar effects). By contrast, in regions that will likely experience increased water availability due to climate change alone, vegetation changes will counteract these increases due to increased water losses by interception. In only a small minority of locations, climate change-induced vegetation changes may lead to a net increase in water availability. These results suggest that changes in vegetation in response to climate change may exacerbate drought conditions and may dampen the effects of increased precipitation, that is, leading to more ecological droughts despite higher precipitation in some regions. Our results underscore the value of considering indirect effects of climate change on vegetation when assessing future soil moisture conditions in water

Climate change-induced vegetation shifts lead to more ecological droughts despite projected rainfall increases in many global temperate drylands

Science.gov (United States)

Tietjen, Britta; Schlaepfer, Daniel R.; Bradford, John B.; Laurenroth, William K.; Hall, Sonia A.; Duniway, Michael C.; Hochstrasser, Tamara; Jia, Gensuo; Munson, Seth M.; Pyke, David A.; Wilson, Scott D.

2017-01-01

Drylands occur world-wide and are particularly vulnerable to climate change since dryland ecosystems depend directly on soil water availability that may become increasingly limited as temperatures rise. Climate change will both directly impact soil water availability, and also change plant biomass, with resulting indirect feedbacks on soil moisture. Thus, the net impact of direct and indirect climate change effects on soil moisture requires better understanding.We used the ecohydrological simulation model SOILWAT at sites from temperate dryland ecosystems around the globe to disentangle the contributions of direct climate change effects and of additional indirect, climate change-induced changes in vegetation on soil water availability. We simulated current and future climate conditions projected by 16 GCMs under RCP 4.5 and RCP 8.5 for the end of the century. We determined shifts in water availability due to climate change alone and due to combined changes of climate and the growth form and biomass of vegetation.Vegetation change will mostly exacerbate low soil water availability in regions already expected to suffer from negative direct impacts of climate change (with the two RCP scenarios giving us qualitatively similar effects). By contrast, in regions that will likely experience increased water availability due to climate change alone, vegetation changes will counteract these increases due to increased water losses by interception. In only a small minority of locations, climate change induced vegetation changes may lead to a net increase in water availability. These results suggest that changes in vegetation in response to climate change may exacerbate drought conditions and may dampen the effects of increased precipitation, i.e. leading to more ecological droughts despite higher precipitation in some regions. Our results underscore the value of considering indirect effects of climate change on vegetation when assessing future soil moisture conditions in water

A minimal model of fire-vegetation feedbacks and disturbance stochasticity generates alternative stable states in grassland–shrubland–woodland systems

International Nuclear Information System (INIS)

Batllori, Enric; Ackerly, David D; Moritz, Max A

2015-01-01

Altered disturbance regimes in the context of global change are likely to have profound consequences for ecosystems. Interactions between fire and vegetation are of particular interest, as fire is a major driver of vegetation change, and vegetation properties (e.g., amount, flammability) alter fire regimes. Mediterranean-type ecosystems (MTEs) constitute a paradigmatic example of temperate fire-prone vegetation. Although these ecosystems may be heavily impacted by global change, disturbance regime shifts and the implications of fire-vegetation feedbacks in the dynamics of such biomes are still poorly characterized. We developed a minimal modeling framework incorporating key aspects of fire ecology and successional processes to evaluate the relative influence of extrinsic and intrinsic factors on disturbance and vegetation dynamics in systems composed of grassland, shrubland, and woodland mosaics, which characterize many MTEs. In this theoretical investigation, we performed extensive simulations representing different background rates of vegetation succession and disturbance regime (fire frequency and severity) processes that reflect a broad range of MTE environmental conditions. Varying fire-vegetation feedbacks can lead to different critical points in underlying processes of disturbance and sudden shifts in the vegetation state of grassland–shrubland–woodland systems, despite gradual changes in ecosystem drivers as defined by the environment. Vegetation flammability and disturbance stochasticity effectively modify system behavior, determining its heterogeneity and the existence of alternative stable states in MTEs. Small variations in system flammability and fire recurrence induced by climate or vegetation changes may trigger sudden shifts in the state of such ecosystems. The existence of threshold dynamics, alternative stable states, and contrasting system responses to environmental change has broad implications for MTE management. (letter)

Prevalence of intestinal parasites in vegetables sold in major ...

African Journals Online (AJOL)

Studies were carried out in Ibadan City, South-West Nigeria between March and June 2011, to determine the prevalence of intestinal parasites in vegetables sold in various markets within the city. Fifty samples each of 5 different vegetable types, Cabbage (Brassica deracea), Lettuce (Lactus sativa), Carrot (Daucus carota), ...

Halotolerant PGPRs Prevent Major Shifts in Indigenous Microbial Community Structure Under Salinity Stress.

Science.gov (United States)

Bharti, Nidhi; Barnawal, Deepti; Maji, Deepamala; Kalra, Alok

2015-07-01

The resilience of soil microbial populations and processes to environmental perturbation is of increasing interest as alteration in rhizosphere microbial community dynamics impacts the combined functions of plant-microbe interactions. The present study was conducted to investigate the effect of inoculation with halotolerant rhizobacteria Bacillus pumilus (STR2), Halomonas desiderata (STR8), and Exiguobacterium oxidotolerans (STR36) on the indigenous root-associated microbial (bacterial and fungal) communities in maize under non-saline and salinity stress. Plants inoculated with halotolerant rhizobacteria recorded improved growth as illustrated by significantly higher shoot and root dry weight and elongation in comparison to un-inoculated control plants under both non-saline and saline conditions. Additive main effect and multiplicative interaction ordination analysis revealed that plant growth promoting rhizobacteria (PGPR) inoculations as well as salinity are major drivers of microbial community shift in maize rhizosphere. Salinity negatively impacts microbial community as analysed through diversity indices; among the PGPR-inoculated plants, STR2-inoculated plants recorded higher values of diversity indices. As observed in the terminal-restriction fragment length polymorphism analysis, the inoculation of halotolerant rhizobacteria prevents major shift of the microbial community structure, thus enhancing the resilience capacity of the microbial communities.

A plant distribution shift: temperature, drought or past disturbance?

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Dylan W Schwilk

Full Text Available Simple models of plant response to warming climates predict vegetation moving to cooler and/or wetter locations: in mountainous regions shifting upslope. However, species-specific responses to climate change are likely to be much more complex. We re-examined a recently reported vegetation shift in the Santa Rosa Mountains, California, to better understand the mechanisms behind the reported shift of a plant distribution upslope. We focused on five elevational zones near the center of the gradient that captured many of the reported shifts and which are dominated by fire-prone chaparral. Using growth rings, we determined that a major assumption of the previous work was wrong: past fire histories differed among elevations. To examine the potential effect that this difference might have on the reported upward shift, we focused on one species, Ceanothus greggii: a shrub that only recruits post-fire from a soil stored seedbank. For five elevations used in the prior study, we calculated time series of past per-capita mortality rates by counting growth rings on live and dead individuals. We tested three alternative hypotheses explaining the past patterns of mortality: 1 mortality increased over time consistent with climate warming, 2 mortality was correlated with drought indices, and 3 mortality peaked 40-50 years post fire at each site, consistent with self-thinning. We found that the sites were different ages since the last fire, and that the reported increase in the mean elevation of C. greggii was due to higher recent mortality at the lower elevations, which were younger sites. The time-series pattern of mortality was best explained by the self-thinning hypothesis and poorly explained by gradual warming or drought. At least for this species, the reported distribution shift appears to be an artifact of disturbance history and is not evidence of a climate warming effect.

Soil warming and CO2 enrichment induce biomass shifts in alpine tree line vegetation.

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Dawes, Melissa A; Philipson, Christopher D; Fonti, Patrick; Bebi, Peter; Hättenschwiler, Stephan; Hagedorn, Frank; Rixen, Christian

2015-05-01

Responses of alpine tree line ecosystems to increasing atmospheric CO2 concentrations and global warming are poorly understood. We used an experiment at the Swiss tree line to investigate changes in vegetation biomass after 9 years of free air CO2 enrichment (+200 ppm; 2001-2009) and 6 years of soil warming (+4 °C; 2007-2012). The study contained two key tree line species, Larix decidua and Pinus uncinata, both approximately 40 years old, growing in heath vegetation dominated by dwarf shrubs. In 2012, we harvested and measured biomass of all trees (including root systems), above-ground understorey vegetation and fine roots. Overall, soil warming had clearer effects on plant biomass than CO2 enrichment, and there were no interactive effects between treatments. Total plant biomass increased in warmed plots containing Pinus but not in those with Larix. This response was driven by changes in tree mass (+50%), which contributed an average of 84% (5.7 kg m(-2) ) of total plant mass. Pinus coarse root mass was especially enhanced by warming (+100%), yielding an increased root mass fraction. Elevated CO2 led to an increased relative growth rate of Larix stem basal area but no change in the final biomass of either tree species. Total understorey above-ground mass was not altered by soil warming or elevated CO2 . However, Vaccinium myrtillus mass increased with both treatments, graminoid mass declined with warming, and forb and nonvascular plant (moss and lichen) mass decreased with both treatments. Fine roots showed a substantial reduction under soil warming (-40% for all roots soil depth) but no change with CO2 enrichment. Our findings suggest that enhanced overall productivity and shifts in biomass allocation will occur at the tree line, particularly with global warming. However, individual species and functional groups will respond differently to these environmental changes, with consequences for ecosystem structure and functioning. © 2014 John Wiley & Sons Ltd.

Treeline advances and associated shifts in the ground vegetation alter fine root dynamics and mycelia production in the South and Polar Urals.

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Solly, Emily F; Djukic, Ika; Moiseev, Pavel A; Andreyashkina, Nelly I; Devi, Nadezhda M; Göransson, Hans; Mazepa, Valeriy S; Shiyatov, Stepan G; Trubina, Marina R; Schweingruber, Fritz H; Wilmking, Martin; Hagedorn, Frank

2017-02-01

Climate warming is shifting the elevational boundary between forests and tundra upwards, but the related belowground responses are poorly understood. In the pristine South and Polar Urals with shifts of the treeline ecotone documented by historical photographs, we investigated fine root dynamics and production of extramatrical mycorrhizal mycelia (EMM) along four elevational transects reaching from the closed forest to the treeless tundra. In addition, we analysed elevational differences in climate and vegetation structure, and excavated trees to estimate related changes in the partitioning between below- and aboveground biomass. Fine root biomass of trees (<2 mm) increased by 13-79% with elevation, paralleled by a 35-72% increase in ground vegetation fine roots from the closed forest to the tundra. During the first year of decomposition, mass loss of fine root litter from different vegetation types was greater at lower elevations in the forest-tundra ecotone. The ratio between fine roots of trees and stem biomass largely increased with elevation in both regions, but these increases were not accompanied by a distinct production of EMM. Production of EMM, however, increased with the presence of ectomycorrhizal trees at the transition from the tundra to the forest. Our results imply that the recorded upward expansion of forest into former tundra in the Ural Mountains by 4-8 m per decade is decreasing the partitioning of plant biomass to fine roots. They further suggest that climate-driven forest advances will alter EMM production rates with potential feedbacks on soil carbon and nutrient cycling in these ecosystems.

Major role of marine vegetation on the oceanic carbon cycle

NARCIS (Netherlands)

Duarte, C.M.; Middelburg, J.J.; Caraco, N.

2005-01-01

The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove

Major role of marine vegetation on the oceanic carbon cycle

Directory of Open Access Journals (Sweden)

C. M. Duarte

2005-01-01

Full Text Available The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove forests to the global level and a top-down approach derived from considerations of global sediment balance and a compilation of the organic carbon content of vegeatated sediments. Up-scaling of individual burial estimates values yielded a total carbon burial in vegetated habitats of 111 Tmol C y-1. The total burial in unvegetated sediments was estimated to be 126 Tg C y-1, resulting in a bottom-up estimate of total burial in the ocean of about 244 Tg C y-1, two-fold higher than estimates of oceanic carbon burial that presently enter global carbon budgets. The organic carbon concentrations in vegetated marine sediments exceeds by 2 to 10-fold those in shelf/deltaic sediments. Top-down recalculation of ocean sediment budgets to account for these, previously neglected, organic-rich sediments, yields a top-down carbon burial estimate of 216 Tg C y-1, with vegetated coastal habitats contributing about 50%. Even though vegetated carbon burial contributes about half of the total carbon burial in the ocean, burial represents a small fraction of the net production of these ecosystems, estimated at about 3388 Tg C y-1, suggesting that bulk of the benthic net ecosystem production must support excess respiration in other compartments, such as unvegetated sediments and the coastal pelagic compartment. The total excess organic carbon available to be exported to the ocean is estimated at between 1126 to 3534 Tg C y-1, the bulk of which must be respired in the open ocean. Widespread loss of vegetated coastal habitats must have reduced carbon burial in the ocean by about 30 Tg C y-1, identifying the destruction of these ecosystems as an important loss of CO

Successional changes in forest vegetation of National Nature Reserve Dubnik

International Nuclear Information System (INIS)

Hrabovsky, A.; Balkovic, J.; Kollar, J.

2011-01-01

The aim of this is paper is phyto-sociological assessment of the current status of forest vegetation in the National Nature Reserve Dubnik (Slovakia) towards state documented in 1965. The observed state is assigned to progressive succession, which resulted in regression of large group of light-requiring species and extinction of oak forest community Quercetum pubescenti-roboris. During the reporting period there was a shift towards mezophilest types of forest with relative homogenization of habitat conditions on the major environmental gradients. (authors)

Multielement determination of major-to-ultratrace elements in vegetable samples by ICP-MS and ICP-AES after acid digestion

Energy Technology Data Exchange (ETDEWEB)

Hokura, Akiko; Oguri, Sachiko; Matsuura, Hirotaka; Haraguchi, Hiroki [Dept. of Applied Chemistry, Graduate School of Engineering, Nagoya Univ. (Japan)

2000-06-01

A multielement determination of major-to-ultratrace elements in vegetable samples was carried out by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Spinach samples (0.5 g) were digested with nitric acid and hydrofluoric acid in a Teflon beaker on a hot plate. The decomposed samples were dissolved in a 1 M ( = mol dm{sup -3}) HNO{sub 3} solution containing internal standard elements (Ge, In, and Re, 10 ppb each), and were subjected to multielement analyses by ICP-AES and ICP-MS. As a result, about 40 elements were successfully determined over a wide concentration range from % to ppb level. Spinach samples grown in different production areas were also analyzed in order to understand the influences of the environmental conditions on growth. Among the major and minor elements, the values of the coefficient of variance (CV) for B, Mg, P, and K were < 20%, and those for Ca, Na, Al, and Mn were higher than 50%. On the other hand, the values of CV for trace and ultratrace elements were significantly high. Furthermore, the present analytical method was also applied to the determination of major-to-ultratrace elements in various vegetable samples (23 species in 11 families); the similarities and differences of the elemental distributions in vegetables were found in the experimental results. (author)

Multielement determination of major-to-ultratrace elements in vegetable samples by ICP-MS and ICP-AES after acid digestion

International Nuclear Information System (INIS)

Hokura, Akiko; Oguri, Sachiko; Matsuura, Hirotaka; Haraguchi, Hiroki

2000-01-01

A multielement determination of major-to-ultratrace elements in vegetable samples was carried out by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Spinach samples (0.5 g) were digested with nitric acid and hydrofluoric acid in a Teflon beaker on a hot plate. The decomposed samples were dissolved in a 1 M ( = mol dm -3 ) HNO 3 solution containing internal standard elements (Ge, In, and Re, 10 ppb each), and were subjected to multielement analyses by ICP-AES and ICP-MS. As a result, about 40 elements were successfully determined over a wide concentration range from % to ppb level. Spinach samples grown in different production areas were also analyzed in order to understand the influences of the environmental conditions on growth. Among the major and minor elements, the values of the coefficient of variance (CV) for B, Mg, P, and K were < 20%, and those for Ca, Na, Al, and Mn were higher than 50%. On the other hand, the values of CV for trace and ultratrace elements were significantly high. Furthermore, the present analytical method was also applied to the determination of major-to-ultratrace elements in various vegetable samples (23 species in 11 families); the similarities and differences of the elemental distributions in vegetables were found in the experimental results. (author)

Carbon sequestration capacity of shifting sand dune after establishing new vegetation in the Tengger Desert, northern China.

Science.gov (United States)

Yang, Haotian; Li, Xinrong; Wang, Zengru; Jia, Rongliang; Liu, Lichao; Chen, Yongle; Wei, Yongping; Gao, Yanhong; Li, Gang

2014-04-15

Reconstructing vegetation in arid and semiarid areas has become an increasingly important management strategy to realize habitat recovery, mitigate desertification and global climate change. To assess the carbon sequestration potential in areas where sand-binding vegetation has been established on shifting sand dunes by planting xeric shrubs located near the southeastern edge of the Tengger Desert in northern China, we conducted a field investigation of restored dune regions that were established at different times (20, 30, 47, and 55 years ago) in the same area. We quantified the total organic carbon (TOC) in each ecosystem by summing the individual carbon contributions from the soil (soil organic carbon; SOC), shrubs, and grasses in each system. We found that the TOC, as well as the amount of organic carbon in the soil, shrubs, and grasses, significantly increased over time in the restored areas. The average annual rate of carbon sequestration was highest in the first 20 years after restoration (3.26 × 10(-2)kg·m(-2) ·year(-1)), and reached a stable rate (2.14 × 10(-2) kg·m(-2) ·year(-1)) after 47 years. Organic carbon storage in soil represented the largest carbon pool for both restored systems and a system containing native vegetation, accounting for 67.6%-85.0% of the TOC. Carbon in grass root biomass, aboveground grass biomass, litter, aboveground shrub biomass, and shrub root biomass account for 10.0%-21.0%, 0.2%-0.6%, 0.1%-0.2%, 1.7%-12.1% and 0.9%-6.2% of the TOC, respectively. Furthermore, we found that the 55-year-old restored system has the capacity to accumulate more TOC (1.02 kg·m(-2) more) to reach the TOC level found in the natural vegetation system. These results suggest that restoring desert ecosystems may be a cost-effective and environmentally friendly way to sequester CO2 from the atmosphere and mitigate the effects of global climate change. Copyright © 2014 Elsevier B.V. All rights reserved.

Vegetation shift from deciduous to evergreen dwarf shrubs in response to selective herbivory offsets carbon losses: evidence from 19 years of warming and simulated herbivory in the subarctic tundra.

Science.gov (United States)

Ylänne, Henni; Stark, Sari; Tolvanen, Anne

2015-10-01

Selective herbivory of palatable plant species provides a competitive advantage for unpalatable plant species, which often have slow growth rates and produce slowly decomposable litter. We hypothesized that through a shift in the vegetation community from palatable, deciduous dwarf shrubs to unpalatable, evergreen dwarf shrubs, selective herbivory may counteract the increased shrub abundance that is otherwise found in tundra ecosystems, in turn interacting with the responses of ecosystem carbon (C) stocks and CO2 balance to climatic warming. We tested this hypothesis in a 19-year field experiment with factorial treatments of warming and simulated herbivory on the dominant deciduous dwarf shrub Vaccinium myrtillus. Warming was associated with a significantly increased vegetation abundance, with the strongest effect on deciduous dwarf shrubs, resulting in greater rates of both gross ecosystem production (GEP) and ecosystem respiration (ER) as well as increased C stocks. Simulated herbivory increased the abundance of evergreen dwarf shrubs, most importantly Empetrum nigrum ssp. hermaphroditum, which led to a recent shift in the dominant vegetation from deciduous to evergreen dwarf shrubs. Simulated herbivory caused no effect on GEP and ER or the total ecosystem C stocks, indicating that the vegetation shift counteracted the herbivore-induced C loss from the system. A larger proportion of the total ecosystem C stock was found aboveground, rather than belowground, in plots treated with simulated herbivory. We conclude that by providing a competitive advantage to unpalatable plant species with slow growth rates and long life spans, selective herbivory may promote aboveground C stocks in a warming tundra ecosystem and, through this mechanism, counteract C losses that result from plant biomass consumption. © 2015 John Wiley & Sons Ltd.

Heavy metals accumulation in roadside soil and vegetation along a major highway in Libya

International Nuclear Information System (INIS)

Voegborlo, R.B.; Chirgawi, M.B.

2007-01-01

Levels of some heavy metals in soil and vegetation along a major highway in Libya were determined by Atomic Absorption Spectrophotometry. The concentrations of Pb, Cd, Ni, Zn, Cu, Cr and Mn in soil and vegetation all decreased with distance from the road, indicating their relation to traffic. The concentrations of the metals also decreased with depth in the soil profile indicating that the source of the metals was aerial deposition from motor vehicles. Inter-relationships between metals in the soil were highly significant (p < 0.05) suggesting a common source for these metals. Pb and Zn were found to be deposited more than the other metals. Average values for citrus lemon leaves were generally 30 - 65 % of those for Olea europaea leaves. In most cases, between 20-40% of the metals was removable by simple washing with water, indicating that a significant, but not predominant fraction of the metals is in the form of easily-removed particulate matter. Discussion of the results of this study is based on statistical treatment of the data. (au)

Phylogenetic signal and major ecological shifts in the ecomorphological structure of stream fish in two river basins in Brazil

Directory of Open Access Journals (Sweden)

Camilo Andrés Roa-Fuentes

Full Text Available We tested the contribution of the phylogenetic and specific components to the ecomorphological structure of stream fish from the upper Paraguai River and upper São Francisco River basins, and identified nodes in the phylogenetic tree at which major ecological shifts occurred. Fish were sampled between June and October of 2008 in 12 streams (six in each basin. In total, 22 species from the upper Paraguai River basin and 12 from the upper São Francisco River were analyzed. The ecomorphological patterns exhibited phylogenetic signal, indicating that the ecomorphological similarity among species is associated with the degree of relatedness. A strong habitat template is most likely to be the primary cause for a high phylogenetic signal. A significant contribution from the specific component was also detected, supporting the idea that the phylogenetic signal occurs in some clades for some traits, but not in others. The major ecological shifts were observed in the basal nodes, suggesting that ecological niche differences appear to accumulate early in the evolutionary history of major clades. This finding reinforces the role of key traits in the diversification of Neotropical fishes. Ecological shifts in recent groups could be related to morphological modifications associated with habitat use.

The extent of shifts in vegetation phenology between rural and urban areas within a human-dominated region.

Science.gov (United States)

Dallimer, Martin; Tang, Zhiyao; Gaston, Kevin J; Davies, Zoe G

2016-04-01

Urbanization is one of the major environmental challenges facing the world today. One of its particularly pressing effects is alterations to local and regional climate through, for example, the Urban Heat Island. Such changes in conditions are likely to have an impact on the phenology of urban vegetation, which will have knock-on implications for the role that urban green infrastructure can play in delivering multiple ecosystem services. Here, in a human-dominated region, we undertake an explicit comparison of vegetation phenology between urban and rural zones. Using satellite-derived MODIS-EVI data from the first decade of the 20th century, we extract metrics of vegetation phenology (date of start of growing season, date of end of growing season, and length of season) for Britain's 15 largest cities and their rural surrounds. On average, urban areas experienced a growing season 8.8 days longer than surrounding rural zones. As would be expected, there was a significant decline in growing season length with latitude (by 3.4 and 2.4 days/degree latitude in rural and urban areas respectively). Although there is considerable variability in how phenology in urban and rural areas differs across our study cities, we found no evidence that built urban form influences the start, end, or length of the growing season. However, the difference in the length of the growing season between rural and urban areas was significantly negatively associated with the mean disposable household income for a city. Vegetation in urban areas deliver many ecosystem services such as temperature mitigation, pollution removal, carbon uptake and storage, the provision of amenity value for humans and habitat for biodiversity. Given the rapid pace of urbanization and ongoing climate change, understanding how vegetation phenology will alter in the future is important if we wish to be able to manage urban greenspaces effectively.

Understanding Spatial and Temporal Shifts in Blue Carbon, Piermont Marsh, Lower Hudson Estuary, NY

Science.gov (United States)

Peteet, D. M.; Nichols, J. E.; Kenna, T. C.; Corbett, E. J.; Allen, K. A.; Newton, R.; Vincent, S.; Haroon, A.; Shumer, M.

2015-12-01

Piermont Marsh is a National Estuarine Research Reserve (NERR) protected brackish wetland in the lower Hudson Valley. It serves as a nursery for fish, a coastal buffer in storms, a repository of native wetland species unique to the Hudson, and a paleoenvironmental archive. At risk for disappearance due to rising sea level, we assess the present carbon stores and their spatial and temporal variability through time. Determining the depth of peat in transects throughout Piermont Marsh (41°N, 73°55'W), is one step in reconstructing the stores of carbon in the marsh and how they have shifted over millennia. Through the last decade, we have focused field efforts on probing the depths of the marsh through a series of transects and in acquiring sediment cores from which we establish sedimentation rates and carbon storage through time. AMS C-14 dating, XRF fluorescence, pollen analysis, and Cesium-137 provide chronological control for the sedimentation rates, pollution history, and an understanding of the regional and local shifts in vegetation. C-13 and pollen measurements in selected cores indicate major shifts in local vegetation with coastal eutrophication as the marsh has been invaded, first by Typha angustifolia in the nineteenth century and then by Phragmites australis in the twentieth century up to the present. N-15 measurements indicate a large shift in nitrogen as humans have impacted the marsh. We present a comprehensive, three-dimensional view of the effects of climate, vegetation, and human impact on the carbon storage of Piermont Marsh. This project provided a site for a place- and project-based learning through Lamont-Doherty's Secondary School Field Research Program. Many of the field samples were collected by young investigators from schools in New York City and towns near Piermont.

Persistent natural acidification drives major distribution shifts in marine benthic ecosystems

Science.gov (United States)

Linares, C.; Vidal, M.; Canals, M.; Kersting, D. K.; Amblas, D.; Aspillaga, E.; Cebrián, E.; Delgado-Huertas, A.; Díaz, D.; Garrabou, J.; Hereu, B.; Navarro, L.; Teixidó, N.; Ballesteros, E.

2015-01-01

Ocean acidification is receiving increasing attention because of its potential to affect marine ecosystems. Rare CO2 vents offer a unique opportunity to investigate the response of benthic ecosystems to acidification. However, the benthic habitats investigated so far are mainly found at very shallow water (less than or equal to 5 m depth) and therefore are not representative of the broad range of continental shelf habitats. Here, we show that a decrease from pH 8.1 to 7.9 observed in a CO2 vent system at 40 m depth leads to a dramatic shift in highly diverse and structurally complex habitats. Forests of the kelp Laminaria rodriguezii usually found at larger depths (greater than 65 m) replace the otherwise dominant habitats (i.e. coralligenous outcrops and rhodolith beds), which are mainly characterized by calcifying organisms. Only the aragonite-calcifying algae are able to survive in acidified waters, while high-magnesium-calcite organisms are almost completely absent. Although a long-term survey of the venting area would be necessary to fully understand the effects of the variability of pH and other carbonate parameters over the structure and functioning of the investigated mesophotic habitats, our results suggest that in addition of significant changes at species level, moderate ocean acidification may entail major shifts in the distribution and dominance of key benthic ecosystems at regional scale, which could have broad ecological and socio-economic implications. PMID:26511045

Importance of vegetation dynamics for future terrestrial carbon cycling

International Nuclear Information System (INIS)

Ahlström, Anders; Smith, Benjamin; Xia, Jianyang; Luo, Yiqi; Arneth, Almut

2015-01-01

Terrestrial ecosystems currently sequester about one third of anthropogenic CO 2 emissions each year, an important ecosystem service that dampens climate change. The future fate of this net uptake of CO 2 by land based ecosystems is highly uncertain. Most ecosystem models used to predict the future terrestrial carbon cycle share a common architecture, whereby carbon that enters the system as net primary production (NPP) is distributed to plant compartments, transferred to litter and soil through vegetation turnover and then re-emitted to the atmosphere in conjunction with soil decomposition. However, while all models represent the processes of NPP and soil decomposition, they vary greatly in their representations of vegetation turnover and the associated processes governing mortality, disturbance and biome shifts. Here we used a detailed second generation dynamic global vegetation model with advanced representation of vegetation growth and mortality, and the associated turnover. We apply an emulator that describes the carbon flows and pools exactly as in simulations with the full model. The emulator simulates ecosystem dynamics in response to 13 different climate or Earth system model simulations from the Coupled Model Intercomparison Project Phase 5 ensemble under RCP8.5 radiative forcing. By exchanging carbon cycle processes between these 13 simulations we quantified the relative roles of three main driving processes of the carbon cycle; (I) NPP, (II) vegetation dynamics and turnover and (III) soil decomposition, in terms of their contribution to future carbon (C) uptake uncertainties among the ensemble of climate change scenarios. We found that NPP, vegetation turnover (including structural shifts, wild fires and mortality) and soil decomposition rates explained 49%, 17% and 33%, respectively, of uncertainties in modelled global C-uptake. Uncertainty due to vegetation turnover was further partitioned into stand-clearing disturbances (16%), wild fires (0%), stand

Burn Severities, Fire Intensities, and Impacts to Major Vegetation Types from the Cerro Grande Fire

Energy Technology Data Exchange (ETDEWEB)

Balice, Randy G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, Kathryn D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wright, Marjorie A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2004-12-15

The Cerro Grande Fire resulted in major impacts and changes to the ecosystems that were burned. To partially document these effects, we estimated the acreage of major vegetation types that were burned at selected burn severity levels and fire intensity levels. To accomplish this, we adopted independently developed burn severity and fire intensity maps, in combination with a land cover map developed for habitat management purposes, as a basis for the analysis. To provide a measure of confidence in the acreage estimates, the accuracies of these maps were also assessed. In addition, two other maps of comparable quality were assessed for accuracy: one that was developed for mapping fuel risk and a second map that resulted from a preliminary application of an evolutionary computation software system, called GENIE.

Tundra shrubification and tree-line advance amplify arctic climate warming: results from an individual-based dynamic vegetation model

Science.gov (United States)

Zhang, Wenxin; Miller, Paul A.; Smith, Benjamin; Wania, Rita; Koenigk, Torben; Döscher, Ralf

2013-09-01

One major challenge to the improvement of regional climate scenarios for the northern high latitudes is to understand land surface feedbacks associated with vegetation shifts and ecosystem biogeochemical cycling. We employed a customized, Arctic version of the individual-based dynamic vegetation model LPJ-GUESS to simulate the dynamics of upland and wetland ecosystems under a regional climate model-downscaled future climate projection for the Arctic and Subarctic. The simulated vegetation distribution (1961-1990) agreed well with a composite map of actual arctic vegetation. In the future (2051-2080), a poleward advance of the forest-tundra boundary, an expansion of tall shrub tundra, and a dominance shift from deciduous to evergreen boreal conifer forest over northern Eurasia were simulated. Ecosystems continued to sink carbon for the next few decades, although the size of these sinks diminished by the late 21st century. Hot spots of increased CH4 emission were identified in the peatlands near Hudson Bay and western Siberia. In terms of their net impact on regional climate forcing, positive feedbacks associated with the negative effects of tree-line, shrub cover and forest phenology changes on snow-season albedo, as well as the larger sources of CH4, may potentially dominate over negative feedbacks due to increased carbon sequestration and increased latent heat flux.

Quantifying the effects of land use and climate on Holocene vegetation in Europe

Science.gov (United States)

Marquer, Laurent; Gaillard, Marie-José; Sugita, Shinya; Poska, Anneli; Trondman, Anna-Kari; Mazier, Florence; Nielsen, Anne Birgitte; Fyfe, Ralph M.; Jönsson, Anna Maria; Smith, Benjamin; Kaplan, Jed O.; Alenius, Teija; Birks, H. John B.; Bjune, Anne E.; Christiansen, Jörg; Dodson, John; Edwards, Kevin J.; Giesecke, Thomas; Herzschuh, Ulrike; Kangur, Mihkel; Koff, Tiiu; Latałowa, Małgorzata; Lechterbeck, Jutta; Olofsson, Jörgen; Seppä, Heikki

2017-09-01

Early agriculture can be detected in palaeovegetation records, but quantification of the relative importance of climate and land use in influencing regional vegetation composition since the onset of agriculture is a topic that is rarely addressed. We present a novel approach that combines pollen-based REVEALS estimates of plant cover with climate, anthropogenic land-cover and dynamic vegetation modelling results. This is used to quantify the relative impacts of land use and climate on Holocene vegetation at a sub-continental scale, i.e. northern and western Europe north of the Alps. We use redundancy analysis and variation partitioning to quantify the percentage of variation in vegetation composition explained by the climate and land-use variables, and Monte Carlo permutation tests to assess the statistical significance of each variable. We further use a similarity index to combine pollen-based REVEALS estimates with climate-driven dynamic vegetation modelling results. The overall results indicate that climate is the major driver of vegetation when the Holocene is considered as a whole and at the sub-continental scale, although land use is important regionally. Four critical phases of land-use effects on vegetation are identified. The first phase (from 7000 to 6500 BP) corresponds to the early impacts on vegetation of farming and Neolithic forest clearance and to the dominance of climate as a driver of vegetation change. During the second phase (from 4500 to 4000 BP), land use becomes a major control of vegetation. Climate is still the principal driver, although its influence decreases gradually. The third phase (from 2000 to 1500 BP) is characterised by the continued role of climate on vegetation as a consequence of late-Holocene climate shifts and specific climate events that influence vegetation as well as land use. The last phase (from 500 to 350 BP) shows an acceleration of vegetation changes, in particular during the last century, caused by new farming

Remotely Sensed Northern Vegetation Response to Changing Climate: Growing Season and Productivity Perspective

Science.gov (United States)

Ganguly, S.; Park, Taejin; Choi, Sungho; Bi, Jian; Knyazikhin, Yuri; Myneni, Ranga

2016-01-01

Vegetation growing season and maximum photosynthetic state determine spatiotemporal variability of seasonal total gross primary productivity of vegetation. Recent warming induced impacts accelerate shifts on growing season and physiological status over Northern vegetated land. Thus, understanding and quantifying these changes are very important. Here, we first investigate how vegetation growing season and maximum photosynthesis state are evolved and how such components contribute on inter-annual variation of seasonal total gross primary productivity. Furthermore, seasonally different response of northern vegetation to changing temperature and water availability is also investigated. We utilized both long-term remotely sensed data to extract larger scale growing season metrics (growing season start, end and duration) and productivity (i.e., growing season summed vegetation index, GSSVI) for answering these questions. We find that regionally diverged growing season shift and maximum photosynthetic state contribute differently characterized productivity inter-annual variability and trend. Also seasonally different response of vegetation gives different view of spatially varying interaction between vegetation and climate. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern vegetation to changing climate.

Albedo and land surface temperature shift in hydrocarbon seepage potential area, case study in Miri Sarawak Malaysia

International Nuclear Information System (INIS)

Suherman, A; Rahman, M Z A; Busu, I

2014-01-01

The presence of hydrocarbon seepage is generally associated with rock or mineral alteration product exposures, and changes of soil properties which manifest with bare development and stress vegetation. This alters the surface thermodynamic properties, changes the energy balance related to the surface reflection, absorption and emission, and leads to shift in albedo and LST. Those phenomena may provide a guide for seepage detection which can be recognized inexpensively by remote sensing method. District of Miri is used for study area. Available topographic maps of Miri and LANDSAT ETM+ were used for boundary construction and determination albedo and LST. Three land use classification methods, namely fixed, supervised and NDVI base classifications were employed for this study. By the intensive land use classification and corresponding statistical comparison was found a clearly shift on albedo and land surface temperature between internal and external seepage potential area. The shift shows a regular pattern related to vegetation density or NDVI value. In the low vegetation density or low NDVI value, albedo of internal area turned to lower value than external area. Conversely in the high vegetation density or high NDVI value, albedo of internal area turned to higher value than external area. Land surface temperature of internal seepage potential was generally shifted to higher value than external area in all of land use classes. In dense vegetation area tend to shift the temperature more than poor vegetation area

Albedo and land surface temperature shift in hydrocarbon seepage potential area, case study in Miri Sarawak Malaysia

Science.gov (United States)

Suherman, A.; Rahman, M. Z. A.; Busu, I.

2014-02-01

The presence of hydrocarbon seepage is generally associated with rock or mineral alteration product exposures, and changes of soil properties which manifest with bare development and stress vegetation. This alters the surface thermodynamic properties, changes the energy balance related to the surface reflection, absorption and emission, and leads to shift in albedo and LST. Those phenomena may provide a guide for seepage detection which can be recognized inexpensively by remote sensing method. District of Miri is used for study area. Available topographic maps of Miri and LANDSAT ETM+ were used for boundary construction and determination albedo and LST. Three land use classification methods, namely fixed, supervised and NDVI base classifications were employed for this study. By the intensive land use classification and corresponding statistical comparison was found a clearly shift on albedo and land surface temperature between internal and external seepage potential area. The shift shows a regular pattern related to vegetation density or NDVI value. In the low vegetation density or low NDVI value, albedo of internal area turned to lower value than external area. Conversely in the high vegetation density or high NDVI value, albedo of internal area turned to higher value than external area. Land surface temperature of internal seepage potential was generally shifted to higher value than external area in all of land use classes. In dense vegetation area tend to shift the temperature more than poor vegetation area.

Soil-geomorphic heterogeneity governs patchy vegetation dynamics at an arid ecotone.

Science.gov (United States)

Bestelmeyer, Brandon T; Ward, Judy P; Havstad, Kris M

2006-04-01

Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable over a 60-year period, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (<40 m2) patches throughout the study area. The probability that patches were presently vegetated or bare, as well as the probability that vegetation persisted and/or established over the 60-year period, was negatively related to surface calcium carbonate and positively related to subsurface clay content. Thus, only a fraction of the landscape was susceptible to vegetation change, and the sparsely vegetated area probably featured a higher frequency of susceptible soil patches. Patch dynamics and self-organizing processes can be constrained by subtle (and often unrecognized) soil heterogeneity.

ALPINE VEGETATION ECOTONE DYNAMICS IN GANGOTRI CATCHMENT USING REMOTE SENSING TECHNIQUES

Directory of Open Access Journals (Sweden)

C. P. Singh

2012-09-01

Full Text Available Analysis of the satellite imagery reveals two different perspectives of the vegetation ecotone dynamics in Gangotri catchment. On one hand, there is evidence of upward shift in the alpine tree and vegetation ecotone over three decades. On the other hand, there has been densification happening at the past treeline. The time series fAPAR data of two decades from NOAA-AVHRR confirms the greening trend in the area. The density of trees in Chirbasa has gone up whereas in Bhojbasa there is no significant change in NDVI but the number of groves has increased. Near Gaumukh the vegetal activity has not shown any significant change. We found that the treeline extracted from satellite imagery has moved up about 327±80m and other vegetation line has moved up about 401±77m in three decades. The vertical rate of treeline shift is found to be 11m/yr with reference to 1976 treeline; however, this can be 5m/yr if past toposheet records (1924 – 45 are considered as reliable reference. However, the future IPCC scenario based bioclimatic fundamental niche modelling of the Betula utilis (a surrogate to alpine treeline suggests that treeline could be moving upward with an average rate of 3m/yr. This study not only confirms that there is an upward shift of vegetation in the alpine zone of Himalayas, but also indicate that old vegetation ecotones have grown denser

Global vegetation change predicted by the modified Budyko model

Energy Technology Data Exchange (ETDEWEB)

Monserud, R.A.; Tchebakova, N.M.; Leemans, R. (US Department of Agriculture, Moscow, ID (United States). Intermountain Research Station, Forest Service)

1993-09-01

A modified Budyko global vegetation model is used to predict changes in global vegetation patterns resulting from climate change (CO[sub 2] doubling). Vegetation patterns are predicted using a model based on a dryness index and potential evaporation determined by solving radiation balance equations. Climate change scenarios are derived from predictions from four General Circulation Models (GCM's) of the atmosphere (GFDL, GISS, OSU, and UKMO). All four GCM scenarios show similar trends in vegetation shifts and in areas that remain stable, although the UKMO scenario predicts greater warming than the others. Climate change maps produced by all four GCM scenarios show good agreement with the current climate vegetation map for the globe as a whole, although over half of the vegetation classes show only poor to fair agreement. The most stable areas are Desert and Ice/Polar Desert. Because most of the predicted warming is concentrated in the Boreal and Temperate zones, vegetation there is predicted to undergo the greatest change. Most vegetation classes in the Subtropics and Tropics are predicted to expand. Any shift in the Tropics favouring either Forest over Savanna, or vice versa, will be determined by the magnitude of the increased precipitation accompanying global warming. Although the model predicts equilibrium conditions to which many plant species cannot adjust (through migration or microevolution) in the 50-100 y needed for CO[sub 2] doubling, it is not clear if projected global warming will result in drastic or benign vegetation change. 72 refs., 3 figs., 3 tabs.

On the precipice of a "majority-minority" America: perceived status threat from the racial demographic shift affects White Americans' political ideology.

Science.gov (United States)

Craig, Maureen A; Richeson, Jennifer A

2014-06-01

The U.S. Census Bureau projects that racial minority groups will make up a majority of the U.S. national population in 2042, effectively creating a so-called majority-minority nation. In four experiments, we explored how salience of such racial demographic shifts affects White Americans' political-party leanings and expressed political ideology. Study 1 revealed that making California's majority-minority shift salient led politically unaffiliated White Americans to lean more toward the Republican Party and express greater political conservatism. Studies 2, 3a, and 3b revealed that making the changing national racial demographics salient led White Americans (regardless of political affiliation) to endorse conservative policy positions more strongly. Moreover, the results implicate group-status threat as the mechanism underlying these effects. Taken together, this work suggests that the increasing diversity of the nation may engender a widening partisan divide. © The Author(s) 2014.

Tundra shrubification and tree-line advance amplify arctic climate warming: results from an individual-based dynamic vegetation model

International Nuclear Information System (INIS)

Zhang Wenxin; Miller, Paul A; Smith, Benjamin; Wania, Rita; Koenigk, Torben; Döscher, Ralf

2013-01-01

One major challenge to the improvement of regional climate scenarios for the northern high latitudes is to understand land surface feedbacks associated with vegetation shifts and ecosystem biogeochemical cycling. We employed a customized, Arctic version of the individual-based dynamic vegetation model LPJ-GUESS to simulate the dynamics of upland and wetland ecosystems under a regional climate model–downscaled future climate projection for the Arctic and Subarctic. The simulated vegetation distribution (1961–1990) agreed well with a composite map of actual arctic vegetation. In the future (2051–2080), a poleward advance of the forest–tundra boundary, an expansion of tall shrub tundra, and a dominance shift from deciduous to evergreen boreal conifer forest over northern Eurasia were simulated. Ecosystems continued to sink carbon for the next few decades, although the size of these sinks diminished by the late 21st century. Hot spots of increased CH 4 emission were identified in the peatlands near Hudson Bay and western Siberia. In terms of their net impact on regional climate forcing, positive feedbacks associated with the negative effects of tree-line, shrub cover and forest phenology changes on snow-season albedo, as well as the larger sources of CH 4 , may potentially dominate over negative feedbacks due to increased carbon sequestration and increased latent heat flux. (letter)

Association of habitual dietary intake with morningness-eveningness and rotating shift work in Japanese female nurses.

Science.gov (United States)

Yoshizaki, Takahiro; Komatsu, Taiki; Tada, Yuki; Hida, Azumi; Kawano, Yukari; Togo, Fumiharu

2018-03-01

Rotating shift workers are associated with imbalanced dietary intakes. Rotating shift workers and dietary intakes in adults who do not engage in night work have also been shown to be associated with chronotype. However, no studies have examined associations between morningness-eveningness (i.e., the degree to which people prefer to be active in the morning or the evening), rotating shift work and dietary intakes. Therefore, our first purpose was to elucidate the association between morningness-eveningness and habitual food group intakes in rotating shift workers. The second purpose was to elucidate the association of morningness-eveningness and rotating shift work with food group intakes, considering habitual sleep durations. Japanese nurses (1095 day workers and 1464 rotating shift workers) were studied using a self-administered questionnaire. The questionnaire covered habitual dietary intakes, morningness-eveningness and demographic characteristics of the participants. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure self-rated morningness-eveningness. Dietary intakes over the previous 1 month were evaluated using a semi-quantitative food frequency questionnaire. Intakes of pulses, green/yellow vegetables, white vegetables, fruits, algae, eggs, confectioneries/savory snacks and sugar-sweetened beverages were significantly (p food groups, intakes of green/yellow vegetables, white vegetables, fruits and algae were significantly (p food groups were also significantly (p food groups, while rotating shift work was associated only with confectioneries/savory snacks. These results suggest that morningness-eveningness is associated with unbalanced dietary intakes in rotating shift workers as well as day workers, which may partially explain associations between rotating shift work and unfavorable dietary intakes. These findings have important implications for the development of novel strategies for preventing poor health caused

Spatio-Temporal Analysis of Vegetation Dynamics in Relation to Shifting Inundation and Fire Regimes: Disentangling Environmental Variability from Land Management Decisions in a Southern African Transboundary Watershed

Directory of Open Access Journals (Sweden)

Narcisa G. Pricope

2015-07-01

Full Text Available Increasing temperatures and wildfire incidence and decreasing precipitation and river runoff in southern Africa are predicted to have a variety of impacts on the ecology, structure, and function of semi-arid savannas, which provide innumerable livelihood resources for millions of people. This paper builds on previous research that documents change in inundation and fire regimes in the Chobe River Basin (CRB in Namibia and Botswana and proposes to demonstrate a methodology that can be applied to disentangle the effect of environmental variability from land management decisions on changing and ecologically sensitive savanna ecosystems in transboundary contexts. We characterized the temporal dynamics (1985–2010 of vegetation productivity for the CRB using proxies of vegetation productivity and examine the relative importance of shifts in flooding and fire patterns to vegetation dynamics and effects of the association of phases of the El Niño—Southern Oscillation (ENSO on vegetation greenness. Our results indicate that vegetation in these semi-arid environments is highly responsive to climatic fluctuations and the long-term trend is one of increased but heterogeneous vegetation cover. The increased cover and heterogeneity during the growing season is especially noted in communally-managed areas of Botswana where long-term fire suppression has been instituted, in contrast to communal areas in Namibia where heterogeneity in vegetation cover is mostly increasing primarily outside of the growing season and may correspond to mosaic early dry season burns. Observed patterns of increased vegetation productivity and heterogeneity may relate to more frequent and intense burning and higher spatial variability in surface water availability from both precipitation and regional inundation patterns, with implications for global environmental change and adaptation in subsistence-based communities.

Intimations on the Tertiary vegetation of southern Africa

Directory of Open Access Journals (Sweden)

J. A. Coetzee

1983-11-01

Full Text Available Fossil pollen sequences from the Cape Peninsula and the Saldanha region indicate that sub tropical vegetation and climates existed in these regions during the Miocene. The pollen record from the Cape Peninsula may point to the extinction of some taxa by the terminal Miocene/Early Pliocene with the subsequent strong development of macchia. This major change can probably be related to the maximum build-up of the Antarctic ice-cap in the latest Miocene and the accompanying profound palaeoceanographic changes such as the major cooling of the Benguela current with its effect on the aridification of the Namib desert, and the global glacio-eustatic sea level drop.Parallel palynological and lithological studies in the Saldanha region show that prominent Miocene vegetation shifts were linked to profound local changes in the palaeoenvironment associated with the northward migration of the Miocene Berg River. Such studies are of paramount importance for the possible assessment of the causes of changes in the palaeoenvironment and should first be carried out at many more sites over a wide region. It is to some extent premature to draw firm conclusions as to the origin and migration of some taxa in southern Africa. The record of very primitive angiosperms such as the ClavatipolleniteslAscarina complex and Winteraceae is of considerable phytogeographic interest.

Network based early warning indicators of vegetation changes in a land–atmosphere model

NARCIS (Netherlands)

Yin, Z.; Dekker, S.C.; Rietkerk, M.; Hurk, B.J.J.M. van den; Dijkstra, H.A.

2016-01-01

Abstract Numerous model studies demonstrate that ecosystems might not shift smoothly with a gradual change in resource concentration. At specific points, vegetation can suddenly shift from one stable state to another. To predict such undesirable shifts, statistical indicators are proposed for early

Shifting cultivation effects on creek water quality around Barkal Upazila in Chittagong Hill Tracts, Bangladesh

Institute of Scientific and Technical Information of China (English)

Shyamal Karmakar; S.M.Sirajul Haque; M.Mozaffar Hossain; Sohag Miah

2012-01-01

We report the effects of shifting cultivation on water quality in 16 creeks investigated once in 2007 and twice in 2008 in 16 apparently similar small neighboring watersheds,each of 3 to 5 ha,at four locations around Barkal sub-district under Rangamati District of Chittagong Hill Tracts in Bangladesh.Concentrations of SO42-and K+,and pH in creek water were lower,and NO3-N and Na+ concentrations were higher in shifting-cultivation land compared to land with either plantation or natural forest or a combination of these cover types.Shifting cultivation effects on some water quality parameters were not significant due to change in land cover of the watershed between two sampling periods either through introduction of planted tree species or naturally regenerated vegetation.Conductivity and concentrations of HCO3-.PO43-,Ca2+ and Mg2+ in creek water showed no definite trend between shifting cultivation and the other land cover types.At one area near the Forest Range Office of Barkal,creek water pH was 5.8 under land cover with a combination of shifting cultivation and plantation.At this area Na+ concentration in shifting-cultivation land ranged from 32.33 to 33.00 mg·L-1 and in vegetated area from 25.00 to 30.50 mg·L-1 in 2007.At another area,Chaliatali Chara,SO42-concentration in a shifting-cultivation watershed ranged from 4.46 to 10.51 mg·L-1,lower than in a vegetated watershed that ranged from 11.69 to 19.98 mg·L-1 in 2007.SO42-concentration in this shifting-cultivation area ranged from 1.28 to 1.37 mg·L-1 and in the vegetated area from 1.37 to 3.50 mg·L-1 in 2008.

Changes in forest productivity across Alaska consistent with biome shift

Science.gov (United States)

Peter S.A. Beck; Glenn P. Juday; Claire Alix; Valerie A. Barber; Stephen E. Winslow; Emily E. Sousa; Patricia Heiser; James D. Herriges; Scott J. Goetz

2011-01-01

Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest...

Climate change and fire effects on a prairie-woodland ecotone: projecting species range shifts with a dynamic global vegetation model

Science.gov (United States)

King, David A.; Bachelet, Dominique M.; Symstad, Amy J.

2013-01-01

Large shifts in species ranges have been predicted under future climate scenarios based primarily on niche-based species distribution models. However, the mechanisms that would cause such shifts are uncertain. Natural and anthropogenic fires have shaped the distributions of many plant species, but their effects have seldom been included in future projections of species ranges. Here, we examine how the combination of climate and fire influence historical and future distributions of the ponderosa pine–prairie ecotone at the edge of the Black Hills in South Dakota, USA, as simulated by MC1, a dynamic global vegetation model that includes the effects of fire, climate, and atmospheric CO2 concentration on vegetation dynamics. For this purpose, we parameterized MC1 for ponderosa pine in the Black Hills, designating the revised model as MC1-WCNP. Results show that fire frequency, as affected by humidity and temperature, is central to the simulation of historical prairies in the warmer lowlands versus woodlands in the cooler, moister highlands. Based on three downscaled general circulation model climate projections for the 21st century, we simulate greater frequencies of natural fire throughout the area due to substantial warming and, for two of the climate projections, lower relative humidity. However, established ponderosa pine forests are relatively fire resistant, and areas that were initially wooded remained so over the 21st century for most of our future climate x fire management scenarios. This result contrasts with projections for ponderosa pine based on climatic niches, which suggest that its suitable habitat in the Black Hills will be greatly diminished by the middle of the 21st century. We hypothesize that the differences between the future predictions from these two approaches are due in part to the inclusion of fire effects in MC1, and we highlight the importance of accounting for fire as managed by humans in assessing both historical species distributions

Climate change and fire effects on a prairie–woodland ecotone: projecting species range shifts with a dynamic global vegetation model

Science.gov (United States)

King, David A; Bachelet, Dominique M; Symstad, Amy J

2013-01-01

Large shifts in species ranges have been predicted under future climate scenarios based primarily on niche-based species distribution models. However, the mechanisms that would cause such shifts are uncertain. Natural and anthropogenic fires have shaped the distributions of many plant species, but their effects have seldom been included in future projections of species ranges. Here, we examine how the combination of climate and fire influence historical and future distributions of the ponderosa pine–prairie ecotone at the edge of the Black Hills in South Dakota, USA, as simulated by MC1, a dynamic global vegetation model that includes the effects of fire, climate, and atmospheric CO2 concentration on vegetation dynamics. For this purpose, we parameterized MC1 for ponderosa pine in the Black Hills, designating the revised model as MC1-WCNP. Results show that fire frequency, as affected by humidity and temperature, is central to the simulation of historical prairies in the warmer lowlands versus woodlands in the cooler, moister highlands. Based on three downscaled general circulation model climate projections for the 21st century, we simulate greater frequencies of natural fire throughout the area due to substantial warming and, for two of the climate projections, lower relative humidity. However, established ponderosa pine forests are relatively fire resistant, and areas that were initially wooded remained so over the 21st century for most of our future climate x fire management scenarios. This result contrasts with projections for ponderosa pine based on climatic niches, which suggest that its suitable habitat in the Black Hills will be greatly diminished by the middle of the 21st century. We hypothesize that the differences between the future predictions from these two approaches are due in part to the inclusion of fire effects in MC1, and we highlight the importance of accounting for fire as managed by humans in assessing both historical species distributions

Climate change and fire effects on a prairie-woodland ecotone: projecting species range shifts with a dynamic global vegetation model.

Science.gov (United States)

King, David A; Bachelet, Dominique M; Symstad, Amy J

2013-12-01

Large shifts in species ranges have been predicted under future climate scenarios based primarily on niche-based species distribution models. However, the mechanisms that would cause such shifts are uncertain. Natural and anthropogenic fires have shaped the distributions of many plant species, but their effects have seldom been included in future projections of species ranges. Here, we examine how the combination of climate and fire influence historical and future distributions of the ponderosa pine-prairie ecotone at the edge of the Black Hills in South Dakota, USA, as simulated by MC1, a dynamic global vegetation model that includes the effects of fire, climate, and atmospheric CO2 concentration on vegetation dynamics. For this purpose, we parameterized MC1 for ponderosa pine in the Black Hills, designating the revised model as MC1-WCNP. Results show that fire frequency, as affected by humidity and temperature, is central to the simulation of historical prairies in the warmer lowlands versus woodlands in the cooler, moister highlands. Based on three downscaled general circulation model climate projections for the 21st century, we simulate greater frequencies of natural fire throughout the area due to substantial warming and, for two of the climate projections, lower relative humidity. However, established ponderosa pine forests are relatively fire resistant, and areas that were initially wooded remained so over the 21st century for most of our future climate x fire management scenarios. This result contrasts with projections for ponderosa pine based on climatic niches, which suggest that its suitable habitat in the Black Hills will be greatly diminished by the middle of the 21st century. We hypothesize that the differences between the future predictions from these two approaches are due in part to the inclusion of fire effects in MC1, and we highlight the importance of accounting for fire as managed by humans in assessing both historical species distributions and

Lateral variations in vegetation in the Himalaya since the Miocene and implications for climate evolution

Science.gov (United States)

Vögeli, Natalie; Najman, Yani; van der Beek, Peter; Huyghe, Pascale; Wynn, Peter M.; Govin, Gwladys; van der Veen, Iris; Sachse, Dirk

2017-08-01

The Himalaya has a major influence on global and regional climate, in particular on the Asian monsoon system. The foreland basin of the Himalaya contains a record of tectonics and paleoclimate since the Miocene. Previous work on the evolution of vegetation and climate has focused on the central and western Himalaya, where a shift from C3 to C4 vegetation has been observed at ∼7 Ma and linked to increased seasonality, but the climatic evolution of the eastern part of the orogen is less well understood. In order to track vegetation as a marker of monsoon intensity and seasonality, we analyzed δ13 C and δ18 O values of soil carbonate and associated δ13 C values of bulk organic carbon from previously dated sedimentary sections exposing the syn-orogenic detrital Dharamsala and Siwalik Groups in the west, and, for the first time, the Siwalik Group in the east of the Himalayan foreland basin. Sedimentary records span from 20 to 1 Myr in the west (Joginder Nagar, Jawalamukhi, and Haripur Kolar sections) and from 13 to 1 Myr in the east (Kameng section), respectively. The presence of soil carbonate in the west and its absence in the east is a first indication of long-term lateral climatic variation, as soil carbonate requires seasonally arid conditions to develop. δ13 C values in soil carbonate show a shift from around -10‰ to -2‰ at ∼7 Ma in the west, which is confirmed by δ13 C analyses on bulk organic carbon that show a shift from around -23‰ to -19‰ at the same time. Such a shift in isotopic values is likely to be associated with a change from C3 to C4 vegetation. In contrast, δ13 C values of bulk organic carbon remain at ∼ - 23 ‰ in the east. Thus, our data show that the current east-west variation in climate was established at 7 Ma. We propose that the regional change towards a more seasonal climate in the west is linked to a decrease of the influence of the Westerlies, delivering less winter precipitation to the western Himalaya, while the east

The influence of vegetation dynamics on anthropogenic climate change

Directory of Open Access Journals (Sweden)

U. Port

2012-11-01

Full Text Available In this study, vegetation–climate and vegetation–carbon cycle interactions during anthropogenic climate change are assessed by using the Earth System Model of the Max Planck Institute for Meteorology (MPI ESM that includes vegetation dynamics and an interactive carbon cycle. We assume anthropogenic CO₂ emissions according to the RCP 8.5 scenario in the time period from 1850 to 2120. For the time after 2120, we assume zero emissions to evaluate the response of the stabilising Earth System by 2300.

Our results suggest that vegetation dynamics have a considerable influence on the changing global and regional climate. In the simulations, global mean tree cover extends by 2300 due to increased atmospheric CO₂ concentration and global warming. Thus, land carbon uptake is higher and atmospheric CO₂ concentration is lower by about 40 ppm when considering dynamic vegetation compared to the static pre-industrial vegetation cover. The reduced atmospheric CO₂ concentration is equivalent to a lower global mean temperature. Moreover, biogeophysical effects of vegetation cover shifts influence the climate on a regional scale. Expanded tree cover in the northern high latitudes results in a reduced albedo and additional warming. In the Amazon region, declined tree cover causes a regional warming due to reduced evapotranspiration. As a net effect, vegetation dynamics have a slight attenuating effect on global climate change as the global climate cools by 0.22 K due to natural vegetation cover shifts in 2300.

A new method to infer vegetation boundary movement from 'snapshot' data

NARCIS (Netherlands)

Eppinga, M.B.; Pucko, C.A.; Baudena, M.; Beckage, B.; Molofsky, J.

2012-01-01

Global change may induce shifts in plant community distributions at multiple spatial scales. At the ecosystem scale, such shifts may result in movement of ecotones or vegetation boundaries. Most indicators for ecosystem change require timeseries data, but here a new method is proposed enabling

Humid to arid to subhumid vegetation shift on Pilliga Sandstone, Ulungra Springs, New South Wales

Science.gov (United States)

Dodson, J. R.; Wright, R. V. S.

1989-09-01

The Pilliga Sandstone region of the northwest slope of New South Wales has a natural vegetation cover of sclerophyllous relatively closed to open forests with a largely heathy understorey, and a warm, subhumid and continental climate. Pollen analysis of spring-fed deposits gives a vegetation history extending from at least 30,000 yr B.P. to the late Holocene. Tree pollen became scarce after about 25,000 yr B.P. and an assemblage dominated by Chenopodiaceae, Liguliflorae, Tubuliflorae, and probably Poaceae developed. No similar assemblage is known from present pollen rain studies carried out in Australia. However, it clearly represents a treeless open shrub-steppe formation and therefore an arid or semiarid environment. The site thus provides evidence of an eastward late Pleistocene extension of the arid zone in Australia, and is the first full-glacial vegetation record between 20° and 35° latitude in Australia. The present vegetation cover did not become reestablished until the beginning of the Holocene, which raises questions about the form in which Pilliga Sandstone vegetation survived full-glacial conditions.

High pressure effects on fruits and vegetables

NARCIS (Netherlands)

Timmermans, R.A.H.; Matser, A.M.

2016-01-01

The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure

Acceleration and Counteraction of Changes in Vegetation Seasonality and Patterns using CMIP5 Projections from Different ESMs.

Science.gov (United States)

Chavaillaz, Y.; Joussaume, S.; De Noblet-Decoudre, N.

2017-12-01

Most climatological studies characterize future climate change as the evolution between a fixed current baseline and the future. Considering the pace of future climate change is however of major importance, since it may strongly influence how we experience climate hazards. To complement previous work related to the pace of temperature and precipitation changes, we propose here to study how fast vegetation seasonality and patterns of climate change evolve in different future configurations according to CMIP5 simulations of several Earth system models. The pace is defined as the difference in relevant metrics between two successive 20-year periods, i.e. with a continually moving baseline. Shifts of vegetation groups and changes in the characteristics of the seasonal cycle are considered. Both accelerate in close relationship with the warming rate regardless of the selected scenario, but they balance each other out, especially for trees in northern mid- and high-latitudes. Efforts are nevertheless strongly needed to harmonize the representation of vegetation in new versions of model inter-comparison projects, in order to properly conduct multi-model analyses related to vegetation changes.

Relationships between vegetation and climate change in Transbaikalia, Siberia

Energy Technology Data Exchange (ETDEWEB)

Tchebakova, N.M.; Parfenova, E.I. [V.N. Sukachev Inst. of Forest, Russian Academy of Sciences, Siberian Branch, Akademgorodok, Krasnoyarsk (Russian Federation)

2002-10-01

This paper demonstrated how vegetation of the Lake Baikal basin may respond to climate change at a mountain biome (an orobiome over the entire basin) and a stand in a locality. An orobiome vegetation model was developed along with a higher resolution stand model based on climatic parameters. Regional climates were modeled based on physiology and site climates based on topography. Bioclimatic multiple regression models were then developed to predict regional vegetation and forest stand characteristics distribution over a mountain range in Central Transbaikalia under current and future climate scenarios. Bioclimatic models were combined with climatic layers of different resolutions. Tree species composition and wood volume was predicted based on 2 climate indices - temperature sums (base 5 degrees C) and the dryness index. Results indicate that lowland vegetation will shift 250 m upslope and highland vegetation will shift 450 m upslope. This will significantly reduce the tundra and light-needled taiga, and will expand the forest-steppe. Results also indicate that the total phytomass within the entire basin will not change much. Stand phytomass across the basin will, however, increase. The model used in this study does not include climate-forcing factors such as wind, snow and permafrost. The model is open to new development to include a dynamic components that would inject vitality into the model. 13 refs., 2 tabs., 3 figs.

Large-scale impact of climate change vs. land-use change on future biome shifts in Latin America.

Science.gov (United States)

Boit, Alice; Sakschewski, Boris; Boysen, Lena; Cano-Crespo, Ana; Clement, Jan; Garcia-Alaniz, Nashieli; Kok, Kasper; Kolb, Melanie; Langerwisch, Fanny; Rammig, Anja; Sachse, René; van Eupen, Michiel; von Bloh, Werner; Clara Zemp, Delphine; Thonicke, Kirsten

2016-11-01

Climate change and land-use change are two major drivers of biome shifts causing habitat and biodiversity loss. What is missing is a continental-scale future projection of the estimated relative impacts of both drivers on biome shifts over the course of this century. Here, we provide such a projection for the biodiverse region of Latin America under four socio-economic development scenarios. We find that across all scenarios 5-6% of the total area will undergo biome shifts that can be attributed to climate change until 2099. The relative impact of climate change on biome shifts may overtake land-use change even under an optimistic climate scenario, if land-use expansion is halted by the mid-century. We suggest that constraining land-use change and preserving the remaining natural vegetation early during this century creates opportunities to mitigate climate-change impacts during the second half of this century. Our results may guide the evaluation of socio-economic scenarios in terms of their potential for biome conservation under global change. © 2016 John Wiley & Sons Ltd.

Vegetation dynamics at the upper elevational limit of vascular plants in Himalaya.

Science.gov (United States)

Dolezal, Jiri; Dvorsky, Miroslav; Kopecky, Martin; Liancourt, Pierre; Hiiesalu, Inga; Macek, Martin; Altman, Jan; Chlumska, Zuzana; Rehakova, Klara; Capkova, Katerina; Borovec, Jakub; Mudrak, Ondrej; Wild, Jan; Schweingruber, Fritz

2016-05-04

A rapid warming in Himalayas is predicted to increase plant upper distributional limits, vegetation cover and abundance of species adapted to warmer climate. We explored these predictions in NW Himalayas, by revisiting uppermost plant populations after ten years (2003-2013), detailed monitoring of vegetation changes in permanent plots (2009-2012), and age analysis of plants growing from 5500 to 6150 m. Plant traits and microclimate variables were recorded to explain observed vegetation changes. The elevation limits of several species shifted up to 6150 m, about 150 vertical meters above the limit of continuous plant distribution. The plant age analysis corroborated the hypothesis of warming-driven uphill migration. However, the impact of warming interacts with increasing precipitation and physical disturbance. The extreme summer snowfall event in 2010 is likely responsible for substantial decrease in plant cover in both alpine and subnival vegetation and compositional shift towards species preferring wetter habitats. Simultaneous increase in summer temperature and precipitation caused rapid snow melt and, coupled with frequent night frosts, generated multiple freeze-thaw cycles detrimental to subnival plants. Our results suggest that plant species responses to ongoing climate change will not be unidirectional upward range shifts but rather multi-dimensional, species-specific and spatially variable.

Seasonally asymmetric enhancement of northern vegetation productivity

Science.gov (United States)

Park, T.; Myneni, R.

2017-12-01

Multiple evidences of widespread greening and increasing terrestrial carbon uptake have been documented. In particular, enhanced gross productivity of northern vegetation has been a critical role leading to observed carbon uptake trend. However, seasonal photosynthetic activity and its contribution to observed annual carbon uptake trend and interannual variability are not well understood. Here, we introduce a multiple-source of datasets including ground, atmospheric and satellite observations, and multiple process-based global vegetation models to understand how seasonal variation of land surface vegetation controls a large-scale carbon exchange. Our analysis clearly shows a seasonally asymmetric enhancement of northern vegetation productivity in growing season during last decades. Particularly, increasing gross productivity in late spring and early summer is obvious and dominant driver explaining observed trend and variability. We observe more asymmetric productivity enhancement in warmer region and this spatially varying asymmetricity in northern vegetation are likely explained by canopy development rate, thermal and light availability. These results imply that continued warming may facilitate amplifying asymmetric vegetation activity and cause these trends to become more pervasive, in turn warming induced regime shift in northern land.

The impact of the expansion of urban vegetable farming on malaria transmission in major cities of Benin

Directory of Open Access Journals (Sweden)

Kindé Gazard

2010-12-01

Full Text Available Abstract Background Urban agricultural practices are expanding in several cities of the Republic of Benin. This study aims to assess the impact of such practices on transmission of the malaria parasite in major cities of Benin. Method A cross sectional entomological study was carried out from January to December 2009 in two vegetable farming sites in southern Benin (Houeyiho and Acron and one in the northern area (Azèrèkè. The study was based on sampling of mosquitoes by Human Landing Catches (HLC in households close to the vegetable farms and in others located far from the farms. Results During the year of study, 71,678 female mosquitoes were caught by HLC of which 25% (17,920/71,678 were Anopheles species. In the areas surveyed, the main malaria parasite, Plasmodium falciparum was transmitted in the south by Anopheles gambiae s.s. Transmission was high during the two rainy seasons (April to July and October to November but declined in the two dry seasons (December to March and August to September. In the north, transmission occurred from June to October during the rainy season and was vehicled by two members of the An. gambiae complex: Anopheles gambiae s.s. (98% and Anopheles arabiensis (2%. At Houeyiho, Acron and Azèrèkè, the Entomological Inoculation Rates (EIRs and the Human Biting Rates (HBRs were significantly higher during the dry season in Households Close to Vegetable Farms (HCVF than in those located far from the vegetable areas (HFVF (p 0.05. The knock-down resistance (kdr mutation was the main resistance mechanism detected at high frequency (0.86 to 0.91 in An. gambiae s.l. at all sites. The ace-1R mutation was also found but at a very low frequency ( Conclusion These findings showed that communities living close to vegetable farms are permanently exposed to malaria throughout the year, whereas the risk in those living far from such agricultural practices is limited and only critical during the rainy seasons. Measures must be

Work shift duration: a review comparing eight hour and 12 hour shift systems.

Science.gov (United States)

Smith, L; Folkard, S; Tucker, P; Macdonald, I

1998-04-01

Shiftwork is now a major feature of working life across a broad range of industries. The features of the shift systems operated can impact on the wellbeing, performance, and sleep of shiftworkers. This paper reviews the current state of knowledge on one major characteristic of shift rotas-namely, shift duration. Evidence comparing the relative effects of eight hour and 12 hour shifts on fatigue and job performance, safety, sleep, and physical and psychological health are considered. At the organisational level, factors such as the mode of system implementation, attitudes towards shift rotas, sickness absence and turnover, overtime, and moonlighting are discussed. Manual and electronic searches of the shiftwork research literature were conducted to obtain information on comparisons between eight hour and 12 hour shifts. The research findings are largely equivocal. The bulk of the evidence suggests few differences between eight and 12 hour shifts in the way they affect people. There may even be advantages to 12 hour shifts in terms of lower stress levels, better physical and psychological wellbeing, improved durations and quality of off duty sleep as well as improvements in family relations. On the negative side, the main concerns are fatigue and safety. It is noted that a 12 hour shift does not equate with being active for only 12 hours. There can be considerable extension of the person's time awake either side of the shift. However, the effects of longer term exposure to extended work days have been relatively uncharted in any systematic way. Longitudinal comparative research into the chronic impact of the compressed working week is needed.

Discharge/Stage Relations in Vegetated Danish Streams

DEFF Research Database (Denmark)

Larsen, Torben; Frier, Jens-Ole; Vestergaard, Kristian

1990-01-01

This paper describes how the friction in danish streams varies as function of the vegetation. The major species of vegetation are represented. A series of laboratory and field experiments are described, and a hypothesis for the influence of the vegetation on the Manning's n is discussed....

Palynological evidence for Pennsylvanian (Late Carboniferous) vegetation change in the Sydney Coalfield, eastern Canada

Energy Technology Data Exchange (ETDEWEB)

Dimitrova, T.K.; Zodrow, E.L.; Cleal, C.J.; Thomas, B.A. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Geology

2010-07-15

The palynology of elastic samples from seven stratigraphical levels in the late Moscovian Sydney Mines Formation, exposed along the shore at Bras d'Or, Nova Scotia, has been investigated. Most of the samples were from roof shales of major coals; the one sample that was not yielded a much higher proportion of pollen derived from extra-basinal vegetation. The four stratigraphically lower roof shale samples yielded essentially similar palynological spectra, with 39 {+-} 4% lycophytes, 9 {+-} 4% sphenophylls, 23 {+-} 4% tree-ferns, 12 4% other ferns and 5 {+-} 3% cordaites. The palynology of the upper part of the investigated succession suggests a shift in vegetation towards one favouring more marattialean tree-ferns, cordaites and conifers, and fewer lycophytes. This correlates with changes in drainage patterns as the alluvial plain migrated seawards and thus changed water tables. No evidence was found to suggest significant climate change at this time.

Effects of climate change on forest vegetation in the Northern Rockies Region [Chapter 6

Science.gov (United States)

Keane, Robert E.; Mahalovich, Mary Frances; Bollenbacher, Barry L.; Manning, Mary E.; Loehman, Rachel A.; Jain, Terrie B.; Holsinger, Lisa M.; Larson, Andrew J.; Webster, Meredith M.

2018-01-01

The projected rapid changes in climate will affect the unique vegetation assemblages of the Northern Rockies region in myriad ways, both directly through shifts in vegetation growth, mortality, and regeneration, and indirectly through changes in disturbance regimes and interactions with changes in other ecosystem processes, such as hydrology, snow dynamics, and exotic invasions (Bonan 2008; Hansen and Phillips 2015; Hansen et al. 2001; Notaro et al. 2007). These impacts, taken collectively, could change the way vegetation is managed by public land agencies in this area. Some species may be in danger of rapid decreases in abundance, while others may undergo range expansion (Landhäusser et al. 2010). New vegetation communities may form, while historical vegetation complexes may simply shift to other areas of the landscape or become rare. Juxtaposed with climate change concerns are the consequences of other land management policies and past activities, such as fire exclusion, fuels treatments, and grazing. A thorough assessment of the responses of vegetation to projected climate change is needed, along with an evaluation of the vulnerability of important species, communities, and vegetation-related resources that may be influenced by the effects, both direct and indirect, of climate change. This assessment must also account for past management actions and current vegetation conditions and their interactions with future climates.

The Vegetable industry in China; Developments in policies, production, marketing and international trade

NARCIS (Netherlands)

Liu, Y.M.; Jinsong, C.; Zhang XiaoYong, Xiaoyong; Kamphuis, B.M.

2004-01-01

Development of Chinese vegetable industry over the past three decades. The changes of governmental vegetable policy and the major institutions involved. The major production regions in China, their leading vegetable varieties and cultivation technology. The reform of vegetable marketing structure

Corrigendum: on the precipice of a "majority-minority" america: perceived status threat from the racial demographic shift affects white Americans' political ideology.

Science.gov (United States)

2015-06-01

Craig, M. A., & Richeson, J. A. (2014). On the precipice of a "majority-minority" America: Perceived status threat from the racial demographic shift affects White Americans' political ideology. Psychological Science, 25, 1189-1197. (Original DOI: 10.1177/0956797614527113). © The Author(s) 2015.

Dynamics of climatic characteristics influencing vegetation in Siberia

International Nuclear Information System (INIS)

Shulgina, Tamara M; Genina, Elena Yu; Gordov, Evgeny P

2011-01-01

The spatiotemporal pattern of the dynamics of surface air temperature and precipitation and those bioclimatic indices that are based upon factors which control vegetation cover are investigated. Surface air temperature and precipitation data are retrieved from the ECMWF ERA Interim reanalysis and APHRODITE JMA datasets, respectively, which were found to be the closest to the observational data. We created an archive of bioclimatic indices for further detailed studies of interrelations between local climate and vegetation cover changes, which include carbon uptake changes related to changes of vegetation types and amount, as well as with spatial shifts of vegetation zones. Meanwhile, analysis reveals significant positive trends of the growing season length accompanied by a statistically significant increase of the sums of the growing degree days and precipitation over the south of West Siberia. The trends hint at a tendency for an increase of vegetation ecosystems' productivity across the south of West Siberia (55°–60°N, 59°–84°E) in the past several decades and (if sustained) may lead to a future increase of vegetation productivity in this region.

Advances in Remote Sensing for Vegetation Dynamics and Agricultural Management

Science.gov (United States)

Tucker, Compton; Puma, Michael

2015-01-01

Spaceborne remote sensing has led to great advances in the global monitoring of vegetation. For example, the NASA Global Inventory Modeling and Mapping Studies (GIMMS) group has developed widely used datasets from the Advanced Very High Resolution Radiometer (AVHRR) sensors as well as the Moderate Resolution Imaging Spectroradiometer (MODIS) map imagery and normalized difference vegetation index datasets. These data are valuable for analyzing vegetation trends and variability at the regional and global levels. Numerous studies have investigated such trends and variability for both natural vegetation (e.g., re-greening of the Sahel, shifts in the Eurasian boreal forest, Amazonian drought sensitivity) and crops (e.g., impacts of extremes on agricultural production). Here, a critical overview is presented on recent developments and opportunities in the use of remote sensing for monitoring vegetation and crop dynamics.

A morphometric analysis of vegetation patterns in dryland ecosystems

Science.gov (United States)

Mander, Luke; Dekker, Stefan C.; Li, Mao; Mio, Washington; Punyasena, Surangi W.; Lenton, Timothy M.

2017-02-01

Vegetation in dryland ecosystems often forms remarkable spatial patterns. These range from regular bands of vegetation alternating with bare ground, to vegetated spots and labyrinths, to regular gaps of bare ground within an otherwise continuous expanse of vegetation. It has been suggested that spotted vegetation patterns could indicate that collapse into a bare ground state is imminent, and the morphology of spatial vegetation patterns, therefore, represents a potentially valuable source of information on the proximity of regime shifts in dryland ecosystems. In this paper, we have developed quantitative methods to characterize the morphology of spatial patterns in dryland vegetation. Our approach is based on algorithmic techniques that have been used to classify pollen grains on the basis of textural patterning, and involves constructing feature vectors to quantify the shapes formed by vegetation patterns. We have analysed images of patterned vegetation produced by a computational model and a small set of satellite images from South Kordofan (South Sudan), which illustrates that our methods are applicable to both simulated and real-world data. Our approach provides a means of quantifying patterns that are frequently described using qualitative terminology, and could be used to classify vegetation patterns in large-scale satellite surveys of dryland ecosystems.

Post-fire vegetation recovery in Portugal based on spot/vegetation data

Science.gov (United States)

Gouveia, C.; Dacamara, C. C.; Trigo, R. M.

2010-04-01

A procedure is presented that allows identifying large burned scars and the monitoring of vegetation recovery in the years following major fire episodes. The procedure relies on 10-day fields of Maximum Value Composites of Normalized Difference Vegetation Index (MVC-NDVI), with a 1 km×1 km spatial resolution obtained from the VEGETATION instrument. The identification of fire scars during the extremely severe 2003 fire season is performed based on cluster analysis of NDVI anomalies that persist during the vegetative cycle of the year following the fire event. Two regions containing very large burned scars were selected, located in Central and Southwestern Portugal, respectively, and time series of MVC-NDVI analysed before the fire events took place and throughout the post-fire period. It is shown that post-fire vegetation dynamics in the two selected regions may be characterised based on maps of recovery rates as estimated by fitting a monoparametric model of vegetation recovery to MVC-NDVI data over each burned scar. Results indicated that the recovery process in the region located in Central Portugal is mostly related to fire damage rather than to vegetation density before 2003, whereas the latter seems to have a more prominent role than vegetation conditions after the fire episode, e.g. in the case of the region in Southwestern Portugal. These differences are consistent with the respective predominant types of vegetation. The burned area located in Central Portugal is dominated by Pinus Pinaster whose natural regeneration crucially depends on the destruction of seeds present on the soil surface during the fire, whereas the burned scar in Southwestern Portugal was populated by Eucalyptus that may quickly re-sprout from buds after fire. Besides its simplicity, the monoparametric model of vegetation recovery has the advantage of being easily adapted to other low-resolution satellite data, as well as to other types of vegetation indices.

Potential of satellite-derived ecosystem functional attributes to anticipate species range shifts

Science.gov (United States)

Alcaraz-Segura, Domingo; Lomba, Angela; Sousa-Silva, Rita; Nieto-Lugilde, Diego; Alves, Paulo; Georges, Damien; Vicente, Joana R.; Honrado, João P.

2017-05-01

In a world facing rapid environmental changes, anticipating their impacts on biodiversity is of utmost relevance. Remotely-sensed Ecosystem Functional Attributes (EFAs) are promising predictors for Species Distribution Models (SDMs) by offering an early and integrative response of vegetation performance to environmental drivers. Species of high conservation concern would benefit the most from a better ability to anticipate changes in habitat suitability. Here we illustrate how yearly projections from SDMs based on EFAs could reveal short-term changes in potential habitat suitability, anticipating mid-term shifts predicted by climate-change-scenario models. We fitted two sets of SDMs for 41 plant species of conservation concern in the Iberian Peninsula: one calibrated with climate variables for baseline conditions and projected under two climate-change-scenarios (future conditions); and the other calibrated with EFAs for 2001 and projected annually from 2001 to 2013. Range shifts predicted by climate-based models for future conditions were compared to the 2001-2013 trends from EFAs-based models. Projections of EFAs-based models estimated changes (mostly contractions) in habitat suitability that anticipated, for the majority (up to 64%) of species, the mid-term shifts projected by traditional climate-change-scenario forecasting, and showed greater agreement with the business-as-usual scenario than with the sustainable-development one. This study shows how satellite-derived EFAs can be used as meaningful essential biodiversity variables in SDMs to provide early-warnings of range shifts and predictions of short-term fluctuations in suitable conditions for multiple species.

Forest Vegetation Simulator translocation techniques with the Bureau of Land Management's Forest Vegetation Information system database

Science.gov (United States)

Timothy A. Bottomley

2008-01-01

The BLM uses a database, called the Forest Vegetation Information System (FORVIS), to store, retrieve, and analyze forest resource information on a majority of their forested lands. FORVIS also has the capability of easily transferring appropriate data electronically into Forest Vegetation Simulator (FVS) for simulation runs. Only minor additional data inputs or...

Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

DEFF Research Database (Denmark)

Nauta, Ake L.; Heijmans, Monique P.D.; Blok, Daan

2015-01-01

, including expansion of woody vegetation5,6, in response to changing climate conditions. How such vegetation changes contribute to stabilization or destabilization of the permafrost is unknown. Here we present six years of field observations in a shrub removal experiment at a Siberian tundra site. Removing...... the shrub part of the vegetation initiated thawing of ice-rich permafrost, resulting in collapse of the originally elevated shrub patches into waterlogged depressions within five years. This thaw pond development shifted the plots from a methane sink into a methane source. The results of our field......-emitting wet depressions could become more abundant in the lowland tundra landscape, at the cost of permafrost-stabilizing low shrub vegetation....

Effects of Telecoupling on Global Vegetation Dynamics

Science.gov (United States)

Viña, A.; Liu, J.

2016-12-01

With the ever increasing trend in telecoupling processes, such as international trade, all countries around the world are becoming more interdependent. However, the effects of this growing interdependence on vegetation (e.g., shifts in the geographic extent and distribution) remain unknown even though vegetation dynamics are crucially important for food production, carbon sequestration, provision of other ecosystem services, and biodiversity conservation. In this study we evaluate the effects of international trade on the spatio-temporal trajectories of vegetation at national and global scales, using vegetation index imagery collected over more than three decades by the Advanced Very High Resolution Radiometer (AVHRR) satellite sensor series together with concurrent national and international data on international trade (and its associated movement of people, goods, services and information). The spatio-temporal trajectories of vegetation are obtained using the scale of fluctuation technique, which is based on the decomposition of the AVHRR image time series to obtain information on its spatial dependence structure over time. Similar to the correlation length, the scale of fluctuation corresponds to the range over which fluctuations in the vegetation index are spatially correlated. Results indicate that global vegetation has changed drastically over the last three decades. These changes are not uniform across space, with hotspots in active trading countries. This study not only has direct implications for understanding global vegetation dynamics, but also sheds important insights on the complexity of human-nature interactions across telecoupled systems.

Grasshopper species composition shifts following a severe rangeland grasshopper outbreak

Science.gov (United States)

Little is known about how grasshopper species abundances shift during and following severe outbreaks, as sampling efforts usually end when outbreaks subside. Grasshopper densities, species composition and vegetation have infrequently been sampled during and after a severe outbreak in the western U.S...

The marsh vegetation of Kleinmond Lagoon

Directory of Open Access Journals (Sweden)

M. O'Callaghan

1994-10-01

Full Text Available The vegetation of Kleinmond Lagoon suggests that this system is in transition from an estuary to a coastal lake. Two major types of vegetation were recognized, one which is subjected to soil and water conditions of marine origin and the other which is subjected to conditions of terrestrial origin. These vegetation types are discussed and compared to the vegetation of other estuarine systems. Artificial manipulations of the mouth seem to have resulted in sediment deposition and a freshening of the system. These unseasonable manipulations also threaten the continued existence of a number of species in the system.

Collective action on improving environmental and economic performance of vegetable production: Exploring pesticides safety in India

NARCIS (Netherlands)

Aravindakshan, S.; Sherief, A.K.

2015-01-01

From the chemical input-intensive yield-enhancement practices of the Green Revolution era, agricultural research and development focus is gradually shifting towards establishing Good Agricultural Practices (GAP) in fruits and vegetable sector. The dominant problems affecting fruits and vegetables in

Determining productivity gains from herbaceous vegetation management with 'age-shift' calculations

Science.gov (United States)

David B. South; James H. Miller; Mark O. Kimberley; Curtis L. Vanderschaaf

2006-01-01

Gains in stand volume that result from competition control and fertilization are sometimes reported as 'percentage gains'. Because percentage gains arithmetically decline over time asstand volume increases, plantation managers have difficultyin using percentage gains to project growth and revenues. The 'age-shift' method quantifies the year...

Simulated Vegetation Response to Climate Change in California: The Importance of Seasonal Production Patterns

Science.gov (United States)

Kim, J. B.; Pitts, B.

2013-12-01

summarized MC1 outputs under the four climate change projections also by computing statistics by EPA Level 3 Ecoregions. MC1 predicts the greatest shift of vegetation types for the drier biomes of California, including the Sonoran Desert and the Eastern Cascade Slopes and Foothills. Strong shifts are predicted for forest biomes, including the Sierra Nevada (42-74%), and the Coast Range (24-40%). The simulated shifts in vegetation types are mediated by simultaneous changes in live vegetation carbon, which in turn are driven by simulated net primary production (NPP) at a monthly time step. MC1's poor skill in reproducing seasonal variations of NPP when compared to MODIS monthly GPP values suggests that the resulting vegetation type shifts are likely inaccurately predicted by MC1. Improving MC1's algorithm for NPP to more closely track seasonal variations in MODIS GPP should result in more reliable predictions of vegetation response to climate change.

Late Quaternary sedimentary dynamics in Western Amazonia: Implications for the origin of open vegetation/forest contrasts

Science.gov (United States)

Rossetti, D. F.; Bertani, T. C.; Zani, H.; Cremon, E. H.; Hayakawa, E. H.

2012-12-01

This work investigated the evolution of sedimentary environments during the latest Quaternary and their influence on the paradoxical occurrence of open vegetation patches in sharp contact with the Amazonian forest. The approach integrated pre-existing geological and floristic data from lowlands in the Brazilian Amazonia, with remote sensing imagery including multispectral optical images (TM, ETM+, and ASTER), Phased Array L-band Synthetic Aperture Radar (PALSAR), InSAR C-band SRTM-DEMs, and high resolution images obtained from Google Earth™. The detection of an abundance of paleomorphologies provided evidence of a scenario in which constant environmental shifts were linked to the evolution of fluvial and megafan depositional systems. In all studied areas, the open vegetation patches are not random, but associated with sedimentary deposits representative of environments either deactivated during the Holocene or presently in the process of deactivation. Sedimentary evolution would have determined the distribution of wetlands and terra firme in many areas of the Amazonian lowlands, and would have a major impact on the development of open vegetated patches within the modern rainforest. Subsiding areas were filled up with megafan deposits, and many fluvial tributaries were rearranged on the landscape. The close relationship between vegetation and the physical environment suggests that sedimentary history related to the evolution of depositional settings during the latest Quaternary played a major role in the distribution of flooded and non-flooded areas of the Amazonian lowlands, with a direct impact on the distribution of modern floristic patterns. As the depositional sites were abandoned and their sedimentary deposits were exposed to the surface, they became sites suitable for vegetation growth, first of herbaceous species and then of forest. Although climate fluctuations might have been involved, fault reactivation appears to have been the main cause of changes in

Time-delay-induced dynamical behaviors for an ecological vegetation growth system driven by cross-correlated multiplicative and additive noises.

Science.gov (United States)

Wang, Kang-Kang; Ye, Hui; Wang, Ya-Jun; Li, Sheng-Hong

2018-05-14

In this paper, the modified potential function, the stationary probability distribution function (SPDF), the mean growth time and the mean degeneration time for a vegetation growth system with time delay are investigated, where the vegetation system is assumed to be disturbed by cross-correlated multiplicative and additive noises. The results reveal some fact that the multiplicative and additive noises can both reduce the stability and speed up the decline of the vegetation system, while the strength of the noise correlation and time delay can both enhance the stability of the vegetation and slow down the depression process of the ecological system. On the other hand, with regard to the impacts of noises and time delay on the mean development and degeneration processes of the ecological system, it is discovered that 1) in the development process of the vegetation population, the increase of the noise correlation strength and time delay will restrain the regime shift from the barren state to the boom one, while the increase of the additive noise can lead to the fast regime shift from the barren state to the boom one. 2) Conversely, in the depression process of the ecological system, the increase of the strength of the correlation noise and time delay will prevent the regime shift from the boom state to the barren one. Comparatively, the increase of the additive and multiplicative noises can accelerate the regime shift from the boom state to the barren state.

Effects of Solar Geoengineering on Vegetation: Implications for Biodiversity and Conservation

Science.gov (United States)

Dagon, K.; Schrag, D. P.

2017-12-01

Climate change will have significant impacts on vegetation and biodiversity. Solar geoengineering has potential to reduce the climate effects of greenhouse gas emissions through albedo modification, yet more research is needed to better understand how these techniques might impact terrestrial ecosystems. Here we utilize the fully coupled version of the Community Earth System Model to run transient solar geoengineering simulations designed to stabilize radiative forcing starting mid-century, relative to the Representative Concentration Pathway 6 (RCP6) scenario. Using results from 100-year simulations, we analyze model output through the lens of ecosystem-relevant metrics. We find that solar geoengineering improves the conservation outlook under climate change, but there are still potential impacts on biodiversity. Two commonly used climate classification systems show shifts in vegetation under solar geoengineering relative to RCP6, though we acknowledge the associated uncertainties with these systems. We also show that rates of warming and the climate velocity are minimized globally under solar geoengineering by the end of the century, while trends persist over land in the Northern Hemisphere. Shifts in the amplitude of temperature and precipitation seasonal cycles are observed in the results, and have implications for vegetation phenology. Different metrics for vegetation productivity also show decreases under solar geoengineering relative to RCP6, but could be related to the model parameterization of nutrient cycling. Vegetation water cycling is found to be an important mechanism for understanding changes in ecosystems under solar geoengineering.

Climate, people, fire and vegetation: new insights into vegetation dynamics in the Eastern Mediterranean since the 1st century AD

Directory of Open Access Journals (Sweden)

J. Bakker

2013-01-01

Full Text Available Anatolia forms a bridge between Europe, Africa and Asia and is influenced by all three continents in terms of climate, vegetation and human civilisation. Unfortunately, well-dated palynological records focussing on the period from the end of the classical Roman period until subrecent times are rare for Anatolia and completely absent for southwest Turkey, resulting in a lacuna in knowledge concerning the interactions of climatic change, human impact, and environmental change in this important region. Two well-dated palaeoecological records from the Western Taurus Mountains, Turkey, provide a first relatively detailed record of vegetation dynamics from late Roman times until the present in SW Turkey. Combining pollen, non-pollen palynomorphs, charcoal, sedimentological, archaeological data, and newly developed multivariate numerical analyses allows for the disentangling of climatic and anthropogenic influences on vegetation change. Results show changes in both the regional pollen signal as well as local soil sediment characteristics match shifts in regional climatic conditions. Both climatic as well as anthropogenic change had a strong influence on vegetation dynamics and land use. A moist environmental trend during the late-3rd century caused an increase in marshes and wetlands in the moister valley floors, limiting possibilities for intensive crop cultivation at such locations. A mid-7th century shift to pastoralism coincided with a climatic deterioration as well as the start of Arab incursions into the region, the former driving the way in which the vegetation developed afterwards. Resurgence in agriculture was observed in the study during the mid-10th century AD, coinciding with the Medieval Climate Anomaly. An abrupt mid-12th century decrease in agriculture is linked to socio-political change, rather than the onset of the Little Ice Age. Similarly, gradual deforestation occurring from the 16th century onwards has been linked to changes in

Determination of zinc contents in vegetables

International Nuclear Information System (INIS)

Salah-ud-Din; Salariya, A.M.; Yasin, M.

1996-01-01

Zinc content of three groups of vegetables (roots and tuber, leaves and fruits) collected from local markets was determined and are reported here. The determination was made by Atomic Absorption Spectrophotometer. The results obtained show that the zinc content of different vegetables ranged from 6.26-36.80 ppm, 8.80-70-70 ppm and 7.20-35.10 ppm for roots and tubers, fruits of vegetables respectively on dry weight basis. Generally, the values obtained in majority are not above, the maximum permissible limits. (author)

Evaluation of vegetation cover using the normalized difference vegetation index (NDVI

Directory of Open Access Journals (Sweden)

Gabriela Camargos Lima

2013-08-01

Full Text Available Soil loss by water erosion is the main cause of soil degradation in Brazil. However, erosion can be reduced by the presence of vegetation. The Normalized Difference Vegetation Index (NDVI makes it possible to identify the vegetative vigor of crops or natural vegetation which facilities the identification of areas with vegetation covers. This information is very important in identifying the phenomena which might be occurring in a particular area, especially those related to soil degradation by water erosion. Thus, the aim of this work was to assess the canopy cover by using NDVI, checking the image accuracy using the Coverage Index (CI based on the Stocking method, in the Sub-basin of Posses, which belongs to the Cantareira System, located in the Extrema municipality, Minas Gerais, Brazil. Landsat-5 TM images were used. The sub-basin of Posses was very altered in comparison to the surrounding areas. The NDVI technique proved to be a suitable tool to assess the uses that occur in the sub-basin of Posses, as validated by the Stocking methodology. The map derived from NDVI allowed the geographic distribution of different land uses to be observed and allowed for the identification of critical areas in relation to vegetation cover as well. This finding can be used to optimize efforts to recover and protect soil in areas with bare soil and degraded pasture, in order to reduce environmental degradation. The CI has not exceeded 40% for land use classes that occur in the majority of the sub-basin (91%, except in areas of woody vegetation.

Identifying Patterns of Participant Shifts in the Psalms

NARCIS (Netherlands)

Erwich, C.M.

2017-01-01

A great challenge of reading the Hebrew poetry of the Psalms is the identification of participants. The major cause of this problem is a continual shift in person, gender and number (so-called PGN-shifts, or participant shifts) in the text. To account for these PGN-shifts, scholars have always used

Simulating vegetation dynamics in Chile from 21ka BP to present: Effects of climate change on vegetation functions and cover

Science.gov (United States)

Werner, Christian; Liakka, Johan; Schmid, Manuel; Fuentes, Juan-Pablo; Ehlers, Todd A.; Hickler, Thomas

2017-04-01

Vegetation composition and establishment is strongly dependent on climate conditions but also a result of vegetation dynamics (competition for light, water and nutrients). In addition, vegetation exerts control over the development of landscapes as it mediates the climatic and hydrological forces shaping the terrain via hillslope and fluvial processes. At the same time, topography as well as soil texture and soil depth affect the microclimate, soil water storage and rooting space that is defining the environmental envelope for vegetation development. Within the EarthShape research program (www.earthshape.net) we evaluate these interactions by simulating the co-evolution of landscape and vegetation with a dynamic vegetation model (LPJ-GUESS) and a landscape evolution model (LandLab). LPJ-GUESS is a mechanistic model driven by daily or monthly weather data and explicitly simulates vegetation physiology, succession, competition and water and nutrient cycling. Here we present the results of first transient vegetation simulations from 21kyr BP to present-day using the TraCE-21ka climate dataset for four focus sites along the coastal cordillera of Chile that are exposed to a substantial meridional climate gradient (ranging from hyper-arid to humid-temperate conditions). We show that the warming occurring in the region from LGM to present, in addition to the increase of atmospheric CO2 concentrations, led to a shift in vegetation composition and surface cover. Future work will show how these changes resonate in the dynamics of hillslope and fluvial erosion and ultimately bi-directional feedback mechanisms of vegetation development and landscape evolution/ soil formation (see also companion presentation by Schmid et al., this session).

Lead-Lag relationships? Asynchrounous and Abrupt Shifts in Atmospheric Circulation, Temperature, and Vegetation during the 8.2 ka Event in the Eastern Mediterranean at Tenaghi Philippon, Greece

Science.gov (United States)

Niedermeyer, E. M.; Mulch, A.; Pross, J.

2017-12-01

The "8.2 ka event" has been an abrupt and prominent climate perturbation during the Holocene, and is characterized by an episode of generally colder and dryer conditions in the Northern Hemisphere realm. However, evidence to what extent this event has had an impact on climate in the Mediterranean region is ambiguous, in particular with respect to rainfall, temperature and vegetation change on land. Here we present a new, high-resolution record (ø 15 years during the event) of paleotemperatures from the Tenaghi Philippon peat deposit, Eastern Macedonia, Greece, using the MBT'/CBT index based on brGDGTs (branched Glycerol-Dialkyl-Glycerol-Tetraethers). Our data show fairly stable temperatures before the event, which is initiated at 8.1 ka by an abrupt and continuous cooling during the first 35 years of the event. After a short, 10-year episode of minimum temperatures, the event is ended by a similarly abrupt and continuous warming within 38 years. Comparison of our record with a previous study of the stable hydrogen isotopic composition of higher-plant waxes (δDwax) on the same core1 shows that changes in temperature occurred simultaneously with shifts in atmospherics moisture sources (Mediterranean vs Atlantic). Interestingly, further comparison of our data with a previous palynological study of the same core2 reveals that changes in vegetation associated with the 8.2 ka event precede shifts in hydrology and temperature by 100 years. This suggests either pronounced changes in seasonality of temperature and rainfall after the onset of the 8.2 ka event, i.e. at the peak of the event, or that changes in local atmospheric circulation (moisture sources) and temperature where not the initial trigger of changes in vegetation. References: Pross, J., Kotthoff, U., Müller, U.C., Peyron, O., Dormoy, I., Schmiedl, G., Kalaitzidis, S. and Smith, A.M. (2009): Massive perturbation in terrestrial ecosystems of the Eastern Mediterranean region associated with the 8.2 kyr B

Biodiversity of Terrestrial Vegetation during Past Warm Periods

Science.gov (United States)

Davies-Barnard, T.; Valdes, P. J.; Ridgwell, A.

2016-12-01

Previous modelling studies of vegetation have generally used a small number of plant functional types to understand how the terrestrial biosphere responds to climate changes. Whilst being useful for understanding first order climate feedbacks, this climate-envelope approach makes a lot of assumptions about past vegetation being very similar to modern. A trait-based method has the advantage for paleo modelling in that there are substantially less assumptions made. In a novel use of the trait-based dynamic vegetation model JeDi, forced with output from climate model HadCM3, we explore past biodiversity and vegetation carbon changes. We use JeDi to model an optimal 2000 combinations of fifteen different traits to enable assessment of the overall level of biodiversity as well as individual growth strategies. We assess the vegetation shifts and biodiversity changes in past greenhouse periods to better understand the impact on the terrestrial biosphere. This work provides original insights into the response of vegetation and terrestrial carbon to climate and hydrological changes in high carbon dioxide climates over time, including during the Late Permian and Cretaceous. We evaluate how the location of biodiversity hotspots and species richness in past greenhouse climates is different to the present day.

Mechanisms of vegetation-induced channel narrowing of an unregulated canyon river: Results from a natural field-scale experiment

Science.gov (United States)

Manners, Rebecca B.; Schmidt, John C.; Scott, Michael L.

2014-04-01

The lower Yampa River in Yampa Canyon, western Colorado serves as a natural, field-scale experiment, initiated when the invasive riparian plant, tamarisk (Tamarix spp.), colonized an unregulated river. In response to tamarisk's rapid invasion, the channel narrowed by 6% in the widest reaches since 1961. Taking advantage of this unique setting, we reconstructed the geomorphic and vegetation history in order to identify the key mechanisms for which, in the absence of other environmental perturbations, vegetation alters fluvial processes that result in a narrower channel. From our reconstruction, we identified a distinct similarity in the timing and magnitude of tamarisk encroachment and channel change, albeit with a lag in the channel response, thus suggesting tamarisk as the driving force. Within a decade of establishment, tamarisk effectively trapped sediment and, as a result, increased floodplain construction rates. Increasing tamarisk coverage over time also reduced the occurrence of floodplain stripping. Tamarisk recruitment was driven by both hydrologic and hydraulic variables, and the majority of tamarisk plants (84%) established below the stage of the 2-year flood. Thus, upon establishment nearly all plants regularly interact with the flow and sediment transport field. Our analyses were predicated on the hypothesis that the flow regime of the Yampa River was stationary, and that only the riparian vegetation community had changed. While not heavily impacted by water development, we determined that some aspects of the flow regime have shifted. However, this shift, which involved the clustering in time of extremely wet and dry years, did not influence fluvial processes directly. Instead these changes directly impacted riparian vegetation and changes in vegetation cover, in turn, altered fluvial processes. Today, the rate of channel change and new tamarisk recruitment is small. We believe that the rapid expansion of tamarisk and related floodplain construction

Twentieth-century shifts in forest structure in California: Denser forests, smaller trees, and increased dominance of oaks.

Science.gov (United States)

McIntyre, Patrick J; Thorne, James H; Dolanc, Christopher R; Flint, Alan L; Flint, Lorraine E; Kelly, Maggi; Ackerly, David D

2015-02-03

We document changes in forest structure between historical (1930s) and contemporary (2000s) surveys of California vegetation through comparisons of tree abundance and size across the state and within several ecoregions. Across California, tree density in forested regions increased by 30% between the two time periods, whereas forest biomass in the same regions declined, as indicated by a 19% reduction in basal area. These changes reflect a demographic shift in forest structure: larger trees (>61 cm diameter at breast height) have declined, whereas smaller trees (Forest composition in California in the last century has also shifted toward increased dominance by oaks relative to pines, a pattern consistent with warming and increased water stress, and also with paleohistoric shifts in vegetation in California over the last 150,000 y.

Application of a Coupled Vegetation Competition and Groundwater Simulation Model to Study Effects of Sea Level Rise and Storm Surges on Coastal Vegetation

Directory of Open Access Journals (Sweden)

Su Yean Teh

2015-09-01

Full Text Available Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM is integrated into the USGS groundwater model (SUTRA to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

Miocene vegetation shift and climate change: Evidence from the Siwalik of Nepal

Science.gov (United States)

Srivastava, Gaurav; Paudayal, Khum N.; Utescher, Torsten; Mehrotra, R. C.

2018-02-01

We reconstruct climate and vegetation applying the Coexistence Approach (CA) methodology on two palaeofloras recovered from the Lower (middle Miocene; 13-11 Ma) and Middle Siwalik (late Miocene; 9.5-6.8 Ma) sediments of Surai Khola section, Nepal. The reconstructed mean annual temperature (MAT) and cold month mean temperature (CMT) show an increasing trend, while warm month mean temperature (WMT) remains nearly the same during the period. The reconstructed precipitation data indicates that the summer monsoon precipitation was nearly the same during the middle and late Miocene, while the winter season precipitation significantly decreased in the late Miocene. The overall precipitation infers increased rainfall seasonality during the late Miocene. The vegetation during the middle Miocene was dominated by wet evergreen taxa, whereas deciduous ones increased significantly during the late Miocene. The reconstructed climate data indicates that high temperature and significantly low precipitation during the winter season (dry season) in the late Miocene might have enhanced forest fire which favoured the expansion of C4 plants over C3 plants during the period. This idea gets further support not only from a recent forest fire in northern India that was caused by the weakening of winter precipitation, but also from the burnt wood recovered from the late Miocene Siwalik sediments of northern India.

Post-fire vegetation recovery in Portugal based ewline on spot/vegetation data

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C. Gouveia

2010-04-01

Full Text Available A procedure is presented that allows identifying large burned scars and the monitoring of vegetation recovery in the years following major fire episodes. The procedure relies on 10-day fields of Maximum Value Composites of Normalized Difference Vegetation Index (MVC-NDVI, with a 1 km×1 km spatial resolution obtained from the VEGETATION instrument. The identification of fire scars during the extremely severe 2003 fire season is performed based on cluster analysis of NDVI anomalies that persist during the vegetative cycle of the year following the fire event. Two regions containing very large burned scars were selected, located in Central and Southwestern Portugal, respectively, and time series of MVC-NDVI analysed before the fire events took place and throughout the post-fire period. It is shown that post-fire vegetation dynamics in the two selected regions may be characterised based on maps of recovery rates as estimated by fitting a monoparametric model of vegetation recovery to MVC-NDVI data over each burned scar. Results indicated that the recovery process in the region located in Central Portugal is mostly related to fire damage rather than to vegetation density before 2003, whereas the latter seems to have a more prominent role than vegetation conditions after the fire episode, e.g. in the case of the region in Southwestern Portugal. These differences are consistent with the respective predominant types of vegetation. The burned area located in Central Portugal is dominated by Pinus Pinaster whose natural regeneration crucially depends on the destruction of seeds present on the soil surface during the fire, whereas the burned scar in Southwestern Portugal was populated by Eucalyptus that may quickly re-sprout from buds after fire. Besides its simplicity, the monoparametric model of vegetation recovery has the advantage of being easily adapted to other low-resolution satellite data, as well as to other types of vegetation

Atlas of the potential vegetation of Ethiopia

DEFF Research Database (Denmark)

Friis, Ib; Demissew, Sebsebe; van Breugel, Paulo

Based on many years of field work by the two senior authors (Ib Friis and Sebsebe Demissew) and with the application of GIS analyses (by P. van Breugel) 15 major vegetation types in Ethiopia are described and mapped. The book descibes the structure and floristic composition of the vegetation types...

Drivers of treeline shift in different European mountains

Czech Academy of Sciences Publication Activity Database

Cudlín, Pavel; Klopčič, M.; Tognetti, R.; Máliš, F.; Alados, C. L.; Bebi, P.; Grunewald, K.; Zhiyanski, M.; Andonowski, V.; La Porta, N.; Bratanova-Doncheva, S.; Kachaunová, E.; Edwards-Jonášová, Magda; Ninot, J. M.; Rigling, A.; Hofgaard, A.; Hlásný, T.; Skalák, Petr; Wielgolaski, F. E.

2017-01-01

Roč. 73, 1-2 (2017), s. 135-150 ISSN 0936-577X R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LD14039 Institutional support: RVO:67179843 Keywords : Vegetation zone shift * Climate change * Climate models * Treeline ecotone * European mountains * Ecosystem services Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.578, year: 2016

High pressure effects on fruits and vegetables

OpenAIRE

Timmermans, R.A.H.; Matser, A.M.

2016-01-01

The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure treatment can be used for product modification through pressure gelatinization of starch and pressure denaturation of proteins. Key pressure–thermal treatment effects on vitamin, enzymes, flavor, co...

Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming.

Science.gov (United States)

Debouk, Haifa; de Bello, Francesco; Sebastià, Maria-Teresa

2015-01-01

Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only on species diversity and productivity, we further investigated (i) how the structure of community plant functional traits in temperate grasslands respond to experimental warming, and (ii) whether species and functional diversity contribute to a greater stability of grasslands, in terms of vegetation composition and productivity. Intact vegetation turves were extracted from temperate subalpine grassland (highland) in the Eastern Pyrenees and transplanted into a warm continental, experimental site in Lleida, in Western Catalonia (lowland). The impacts of simulated warming on plant production and diversity, functional trait structure, and vegetation compositional stability were assessed. We observed an increase in biomass and a reduction in species and functional diversity under short-term warming. The functional structure of the grassland communities changed significantly, in terms of functional diversity and community-weighted means (CWM) for several traits. Acquisitive and fast-growing species with higher SLA, early flowering, erect growth habit, and rhizomatous strategy became dominant in the lowland. Productivity was significantly positively related to species, and to a lower extent, functional diversity, but productivity and stability after warming were more dependent on trait composition (CWM) than on diversity. The turves with more acquisitive species before warming changed less in composition after warming. Results suggest that (i) the short-term warming can lead to the dominance of acquisitive fast growing species over conservative species, thus reducing species richness, and (ii) the functional traits structure in grassland communities had a greater influence on the productivity and stability of the community under short-term warming

Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming.

Directory of Open Access Journals (Sweden)

Haifa Debouk

Full Text Available Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only on species diversity and productivity, we further investigated (i how the structure of community plant functional traits in temperate grasslands respond to experimental warming, and (ii whether species and functional diversity contribute to a greater stability of grasslands, in terms of vegetation composition and productivity. Intact vegetation turves were extracted from temperate subalpine grassland (highland in the Eastern Pyrenees and transplanted into a warm continental, experimental site in Lleida, in Western Catalonia (lowland. The impacts of simulated warming on plant production and diversity, functional trait structure, and vegetation compositional stability were assessed. We observed an increase in biomass and a reduction in species and functional diversity under short-term warming. The functional structure of the grassland communities changed significantly, in terms of functional diversity and community-weighted means (CWM for several traits. Acquisitive and fast-growing species with higher SLA, early flowering, erect growth habit, and rhizomatous strategy became dominant in the lowland. Productivity was significantly positively related to species, and to a lower extent, functional diversity, but productivity and stability after warming were more dependent on trait composition (CWM than on diversity. The turves with more acquisitive species before warming changed less in composition after warming. Results suggest that (i the short-term warming can lead to the dominance of acquisitive fast growing species over conservative species, thus reducing species richness, and (ii the functional traits structure in grassland communities had a greater influence on the productivity and stability of the community under short

Broad-Scale Environmental Conditions Responsible for Post-Fire Vegetation Dynamics

Directory of Open Access Journals (Sweden)

Stuart E. Marsh

2010-11-01

Full Text Available Ecosystem response to disturbance is influenced by environmental conditions at a number of scales. Changes in climate have altered fire regimes across the western United States, and have also likely altered spatio-temporal patterns of post-fire vegetation regeneration. Fire occurrence data and a vegetation index (NDVI derived from the NOAA Advanced Very High Resolution Radiometer (AVHRR were used to monitor post-fire vegetation from 1989 to 2007. We first investigated differences in post-fire rates of vegetation regeneration between ecoregions. We then related precipitation, temperature, and elevation records at four temporal scales to rates of post-fire vegetation regeneration to ascertain the influence of climate on post-fire vegetation dynamics. We found that broad-scale climate factors are an important influence on post-fire vegetation regeneration. Most notably, higher rates of post-fire regeneration occurred with warmer minimum temperatures. Increases in precipitation also resulted in higher rates of post-fire vegetation growth. While explanatory power was slight, multiple statistical approaches provided evidence for real ecological drivers of post-fire regeneration that should be investigated further at finer scales. The sensitivity of post-disturbance vegetation dynamics to climatic drivers has important ramifications for the management of ecosystems under changing climatic conditions. Shifts in temperature and precipitation regimes are likely to result in changes in post-disturbance dynamics, which could represent important feedbacks into the global climate system.

A survey of brassica vegetable smallholder farmers in the Gauteng and Limpopo provinces of South Africa

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Gloria Mandiriza-Mukwirimba

2016-02-01

Full Text Available A study was taken to investigate the types of brassica vegetables mostly grown by smallholder farmers in two provinces of South Africa. Thirty-one smallholder vegetable farmers in the Gauteng province and Waterberg district in the Limpopo province were surveyed. In addition, the study also sought to establish the common diseases, the management strategies used and problems encountered by the farmers. Farmers were interviewed using a questionnaire with closed and open–ended questions. The results indicated that the smallholder farmers mostly grew cabbage (93.6% as their main brassica crop followed by rape (41.2%. Thirty percent of farmers could not identify or name the predominant disease/s encountered in their fields. Major diseases encountered by farmers surveyed were an unknown disease/s (33.3%, black rot (26.7%, Alternaria leaf spot (6.7% and white rust (6.7%. Smallholder farmers have inadequate technical information available especially relating to crop diseases, their identification and control. Farmers encountered challenges with black rot disease especially on cabbage, rape and kale and the disease was a problem during winter and summer. Generally, the smallholder farmers used crop rotation (74.2% as a major practice to manage the diseases experienced. They rotated their brassica vegetables with other crops/vegetables like tomatoes, onions, beetroots and maize. Most of the farmers interviewed (61.3% did not use chemicals to control diseases, whereas 38.7% of them used chemicals. This was mostly because they lacked information and knowledge, high costs associated with use of chemical fungicides and some were shifting towards organic farming. From the study it was noted that there was a need for technical support to improve farmers’ knowledge on disease identification and control within the surveyed areas.

Vegetation of the Hantam-Tanqua-Roggeveld subregion, South Africa Part 2: Succulent Karoo Biome related vegetation

Directory of Open Access Journals (Sweden)

Helga van der Merwe

2009-03-01

Full Text Available The Hantam-Tanqua-Roggeveld subregion lies within the Succulent Karoo Hotspot that stretches along the western side of the Republic of South Africa and Namibia. This project, carried out to document the botanical diversity in the Hantam-Tanqua-Roggeveld subregion, was part of a project identified as a priority during the SKEP (Succulent Karoo Ecosystem Programme initiative in this Hotspot. Botanical surveys were conducted in an area covering over three million hectares. Satellite images of the area and topocadastral, land type and geology maps were used to stratify the area into relatively homogeneous units. An analysis of the floristic data of 390 sample plots identified two major floristic units, i.e. the Fynbos Biome related vegetation and the Succulent Karoo Biome related vegetation. A description of the vegetation related to the Succulent Karoo Biome is presented in this article. Seven associations, 16 subassociations and several mosaic vegetation units, consisting of more than one vegetation unit, were identified and mapped. Various threats to the vegetation in the region were identified during the survey and are briefly discussed.

Bird species turnover is related to changing predation risk along a vegetation gradient

Science.gov (United States)

LaManna, Joseph A.; Hemenway, Amy B.; Boccadori, Vanna; Martin, Thomas E.

2015-01-01

Turnover in animal species along vegetation gradients is often assumed to reflect adaptive habitat preferences that are narrower than the full gradient. Specifically, animals may decline in abundance where their reproductive success is low, and these poor-quality locations differ among species. Yet habitat use does not always appear adaptive. The crucial tests of how abundances and demographic costs of animals vary along experimentally manipulated vegetation gradients are lacking. We examined habitat use and nest predation rates for 16 bird species that exhibited turnover with shifts in deciduous and coniferous vegetation. For most bird species, decreasing abundance was associated with increasing predation rates along both natural and experimentally modified vegetation gradients. This landscape-scale approach strongly supports the idea that vegetation-mediated effects of predation are associated with animal distributions and species turnover.

Empirical analysis of vegetation dynamics and the possibility of a catastrophic desertification transition.

Science.gov (United States)

Weissmann, Haim; Kent, Rafi; Michael, Yaron; Shnerb, Nadav M

2017-01-01

The process of desertification in the semi-arid climatic zone is considered by many as a catastrophic regime shift, since the positive feedback of vegetation density on growth rates yields a system that admits alternative steady states. Some support to this idea comes from the analysis of static patterns, where peaks of the vegetation density histogram were associated with these alternative states. Here we present a large-scale empirical study of vegetation dynamics, aimed at identifying and quantifying directly the effects of positive feedback. To do that, we have analyzed vegetation density across 2.5 × 106 km2 of the African Sahel region, with spatial resolution of 30 × 30 meters, using three consecutive snapshots. The results are mixed. The local vegetation density (measured at a single pixel) moves towards the average of the corresponding rainfall line, indicating a purely negative feedback. On the other hand, the chance of spatial clusters (of many "green" pixels) to expand in the next census is growing with their size, suggesting some positive feedback. We show that these apparently contradicting results emerge naturally in a model with positive feedback and strong demographic stochasticity, a model that allows for a catastrophic shift only in a certain range of parameters. Static patterns, like the double peak in the histogram of vegetation density, are shown to vary between censuses, with no apparent correlation with the actual dynamical features. Our work emphasizes the importance of dynamic response patterns as indicators of the state of the system, while the usefulness of static modality features appears to be quite limited.

Predicting Changes in Arctic Tundra Vegetation: Towards an Understanding of Plant Trait Uncertainty

Science.gov (United States)

Euskirchen, E. S.; Serbin, S.; Carman, T.; Iversen, C. M.; Salmon, V.; Helene, G.; McGuire, A. D.

2017-12-01

Arctic tundra plant communities are currently undergoing unprecedented changes in both composition and distribution under a warming climate. Predicting how these dynamics may play out in the future is important since these vegetation shifts impact both biogeochemical and biogeophysical processes. More precise estimates of these future vegetation shifts is a key challenge due to both a scarcity of data with which to parameterize vegetation models, particularly in the Arctic, as well as a limited understanding of the importance of each of the model parameters and how they may vary over space and time. Here, we incorporate newly available field data from arctic Alaska into a dynamic vegetation model specifically developed to take into account a particularly wide array of plant species as well as the permafrost soils of the arctic tundra (the Terrestrial Ecosystem Model with Dynamic Vegetation and Dynamic Organic Soil, Terrestrial Ecosystem Model; DVM-DOS-TEM). We integrate the model within the Predicative Ecosystem Analyzer (PEcAn), an open-source integrated ecological bioinformatics toolbox that facilitates the flows of information into and out of process models and model-data integration. We use PEcAn to evaluate the plant functional traits that contribute most to model variability based on a sensitivity analysis. We perform this analysis for the dominant types of tundra in arctic Alaska, including heath, shrub, tussock and wet sedge tundra. The results from this analysis will help inform future data collection in arctic tundra and reduce model uncertainty, thereby improving our ability to simulate Arctic vegetation structure and function in response to global change.

Fine-scale patterns of vegetation assembly in the monitoring of changes in coastal sand-dune landscapes

Directory of Open Access Journals (Sweden)

J. Honrado

2010-02-01

Full Text Available Understanding dune ecosystem responses to multi-scale environmental changes can provide the framework for reliable forecasts and cost-efficient protocols for detecting shifts in prevailing coastal dynamics. Based on the hypothesis that stress and disturbance interact as primary community controls in coastal dunes, we studied the fine-scale floristic assembly of foredune vegetation, in its relation to topography, along regional and local environmental gradients in the 200 km long coastline of northern Portugal, encompassing a major biogeographic transition in western Europe. Thirty topographic profiles perpendicular to the shoreline were recorded at ten sites along the regional climate gradient, and vegetation was sampled by recording the frequency of plant species along those profiles. Quantitative topographic attributes of vegetated dune profiles (e.g. length or height exhibited wide variations relatable to differences in prevailing coastal dynamics. Metrics of taxonomic diversity (e.g. total species richness and its additive beta component and of the functional composition of vegetation were highly correlated to attributes of dune topography. Under transgressive dynamics, vegetation profiles have fewer species, increased dominance, lower turnover rates, and lower total vegetation cover. These changes may drive a decrease in structural and functional diversity, with important consequences for resistance, resilience and other ecosystem properties. Moreover, differences in both vegetation assembly (in meta-stable dunes and response to increased disturbance (in eroding dunes between distinct biogeographic contexts highlight a possible decline in facilitation efficiency under extreme physical stress (i.e. under Mediterranean climate and support the significance of functional approaches in the study of local ecosystem responses to disturbance along regional gradients. Our results strongly suggest that assessing fine-scale community assembly can

Synchronicity in elevation range shifts among small mammal and vegetation over the last century is stronger for omnivores

NARCIS (Netherlands)

Ferreira Dos Santos, Maria Joao; Thorne, James; Moritz, Craig

2015-01-01

In mountain ecosystems, species can be said to respond synchronously to environmental change when the elevation ranges of vegetation types and their associated vertebrates expand or contract in the same direction. Conversely, the response is asynchronous when the elevation ranges of vegetation types

Simulating the vegetation response in western Europe to abrupt climate changes under glacial background conditions

Directory of Open Access Journals (Sweden)

M.-N. Woillez

2013-03-01

Full Text Available The last glacial period has been punctuated by two types of abrupt climatic events, the Dansgaard–Oeschger (DO and Heinrich (HE events. These events, recorded in Greenland ice and in marine sediments, involved changes in the Atlantic Meridional Overturning Circulation (AMOC and led to major changes in the terrestrial biosphere. Here we use the dynamical global vegetation model ORCHIDEE to simulate the response of vegetation to abrupt changes in the AMOC strength. We force ORCHIDEE offline with outputs from the IPSL_CM4 general circulation model, in which the AMOC is forced to change by adding freshwater fluxes in the North Atlantic. We investigate the impact of a collapse and recovery of the AMOC, at different rates, and focus on Western Europe, where many pollen records are available for comparison. The impact of an AMOC collapse on the European mean temperatures and precipitations simulated by the GCM is relatively small but sufficient to drive an important regression of forests and expansion of grasses in ORCHIDEE, in qualitative agreement with pollen data for an HE event. On the contrary, a run with a rapid shift of the AMOC to a hyperactive state of 30 Sv, mimicking the warming phase of a DO event, does not exhibit a strong impact on the European vegetation compared to the glacial control state. For our model, simulating the impact of an HE event thus appears easier than simulating the abrupt transition towards the interstadial phase of a DO. For both a collapse or a recovery of the AMOC, the vegetation starts to respond to climatic changes immediately but reaches equilibrium about 200 yr after the climate equilibrates, suggesting a possible bias in the climatic reconstructions based on pollen records, which assume equilibrium between climate and vegetation. However, our study does not take into account vegetation feedbacks on the atmosphere.

Methodological aspects of shift-work research.

Science.gov (United States)

Knutsson, Anders

2004-01-01

A major issue in shift-work research is to understand the possible ways in which shift work can impact performance and health. Nearly all body functions, from those of the cellular level to those of the entire body, are circadian rhythmic. Disturbances of these rhythms as well as the social consequences of odd work hours are of importance for the health and well-being of shift workers. This article reviews a number of common methodological issues which are of relevance to epidemiological studies in this area of research. It discusses conceptual problems regarding the use of the term "shift work," and it underscores the need to develop models that explain the mechanisms of disease in shift workers.

Trends in landscape and vegetation change and implications for the Santa Cruz Watershed

Science.gov (United States)

Villarreal, Miguel; Norman, Laura M.; Webb, Robert H.; Turner, Raymond M.

2013-01-01

Monitoring and characterizing the interactive effects of land use and climate on land surface processes is a primary focus of land change science, and of particular concern in arid Wells Distribution in Shallow Groundwater Areas Pumping Trends Increase Streamflow Extent Declines 27 environments where both landscapes and livelihoods can be impacted by short-term climate variability. Using a multi-observational approach to land-change analysis that included landownership data as a proxy for land-use practices, multitemporal land-cover maps, and repeat photography dating to the late 19th century, we examine changing spatial and temporal distributions of two vegetation types with high conservation value in the southwestern United States: grasslands and riparian vegetation. Our study area is the bi-national Santa Cruz Watershed, a topographically complex watershed that straddles the Sonoran Desert and the Madrean Archipelago Ecoregions. In this presentation we focus on historical changes in vegetation and land use in grasslands and riparian areas of the Madrean Ecoregion (San Raphael Valley, Cienega Creek, Sonoita), and compare changes in these areas to changes in the warmer and drier Sonoran Ecoregion. Analysis of historical photography confirms major 20th century vegetation shifts documented in other research: woody plant encroachment, desertification of grasslands, and changing riparian and xeroriparian vegetation occurred in both ecoregions following human settlement. However, vegetation changes over the past decade appear to be more subtle and some of the past trajectories appear to be reversing; most notable are recent mesquite declines in xeroriparian and upland areas, and changes from shrubland to grassland area in the Madrean ecoregion. Land cover changes were temporally variable, reflecting broad climate changes. The most dynamic cover changes occurred during the period from 1989 to 1999, a period with two intense droughts. The degree of vegetation change

El Nino Southern Oscillation and vegetation dynamics as predictors of dengue fever cases in Costa Rica

Energy Technology Data Exchange (ETDEWEB)

Fuller, D O [Department of Geography and Regional Studies, University of Miami, Coral Gables, FL 33124-2221 (United States); Troyo, A [Centro de Investigacion en Enfermedades Tropicales, Departamento de ParasitologIa, Facultad de MicrobiologIa, Universidad de Costa Rica, San Jose (Costa Rica); Beier, J C [Global Public Health Program, Department of Epidemiology and Public Health, University of Miami, Miami, FL (United States)], E-mail: dofuller@miami.edu

2009-01-15

Dengue fever (DF) and dengue hemorrhagic fever (DHF) are growing health concerns throughout Latin America and the Caribbean. This study focuses on Costa Rica, which experienced over 100 000 cases of DF/DHF from 2003 to 2007. We utilized data on sea-surface temperature anomalies related to the El Nino Southern Oscillation (ENSO) and two vegetation indices derived from the Moderate Resolution Imaging Spectrometer (MODIS) from the Terra satellite to model the influence of climate and vegetation dynamics on DF/DHF cases in Costa Rica. Cross-correlations were calculated to evaluate both positive and negative lag effects on the relationships between independent variables and DF/DHF cases. The model, which utilizes a sinusoid and non-linear least squares to fit case data, was able to explain 83% of the variance in weekly DF/DHF cases when independent variables were shifted backwards in time. When the independent variables were shifted forward in time, consistently with a forecasting approach, the model explained 64% of the variance. Importantly, when five ENSO and two vegetation indices were included, the model reproduced a major DF/DHF epidemic of 2005. The unexplained variance in the model may be due to herd immunity and vector control measures, although information regarding these aspects of the disease system are generally lacking. Our analysis suggests that the model may be used to predict DF/DHF outbreaks as early as 40 weeks in advance and may also provide valuable information on the magnitude of future epidemics. In its current form it may be used to inform national vector control programs and policies regarding control measures; it is the first climate-based dengue model developed for this country and is potentially scalable to the broader region of Latin America and the Caribbean where dramatic increases in DF/DHF incidence and spread have been observed.

El Nino Southern Oscillation and vegetation dynamics as predictors of dengue fever cases in Costa Rica

International Nuclear Information System (INIS)

Fuller, D O; Troyo, A; Beier, J C

2009-01-01

Dengue fever (DF) and dengue hemorrhagic fever (DHF) are growing health concerns throughout Latin America and the Caribbean. This study focuses on Costa Rica, which experienced over 100 000 cases of DF/DHF from 2003 to 2007. We utilized data on sea-surface temperature anomalies related to the El Nino Southern Oscillation (ENSO) and two vegetation indices derived from the Moderate Resolution Imaging Spectrometer (MODIS) from the Terra satellite to model the influence of climate and vegetation dynamics on DF/DHF cases in Costa Rica. Cross-correlations were calculated to evaluate both positive and negative lag effects on the relationships between independent variables and DF/DHF cases. The model, which utilizes a sinusoid and non-linear least squares to fit case data, was able to explain 83% of the variance in weekly DF/DHF cases when independent variables were shifted backwards in time. When the independent variables were shifted forward in time, consistently with a forecasting approach, the model explained 64% of the variance. Importantly, when five ENSO and two vegetation indices were included, the model reproduced a major DF/DHF epidemic of 2005. The unexplained variance in the model may be due to herd immunity and vector control measures, although information regarding these aspects of the disease system are generally lacking. Our analysis suggests that the model may be used to predict DF/DHF outbreaks as early as 40 weeks in advance and may also provide valuable information on the magnitude of future epidemics. In its current form it may be used to inform national vector control programs and policies regarding control measures; it is the first climate-based dengue model developed for this country and is potentially scalable to the broader region of Latin America and the Caribbean where dramatic increases in DF/DHF incidence and spread have been observed.

Climate-vegetation-fire interactions and their impact on long-term carbon dynamics in a boreal peatland landscape in northern Manitoba, Canada

Science.gov (United States)

Camill, Philip; Barry, Ann; Williams, Evie; Andreassi, Christian; Limmer, Jacob; Solick, Donald

2009-12-01

Climate warming may increase the size and frequency of fires in the boreal biome, possibly causing greater carbon release that amplifies warming. However, in peatlands, vegetation change may also control long-term fire and carbon accumulation, confounding simple relationships between climate, fire, and carbon accumulation. Using 17 peat cores dating to 8000 cal years B.P. from northern Manitoba, Canada, we addressed the following questions: (1) Do past climate changes correlate with shifts in peatland vegetation? (2) What is the relationship between peatland vegetation and fire severity? (3) What is the mean return interval for boreal peat fires, and how does it change across fires of different severities? (4) How does fire severity affect carbon accumulation rates? (5) Do fire and long-term carbon accumulation change directly in response to climate or indirectly though climate-driven changes in vegetation? We measured carbon accumulation rates, fire severity, and return intervals using macroscopic charcoal and changes in vegetation using macrofossils. Climate and vegetation changes covaried, with shifts from wetter fen to drier, forested bog communities during the Holocene Thermal Maximum (HTM). Fires became more severe following the shift to forested bogs, with fire severity peaking after 4000 cal years B.P. rather than during the HTM. Rising fire severity, in turn, was correlated with a significant decrease in carbon accumulation from ˜6000 to 2000 cal years B.P. The Medieval Warm Period and Little Ice Age affected vegetation composition and permafrost, further impacting fire and carbon accumulation. Our results indicate that long-term changes in fire and carbon dynamics are mediated by climate-driven changes in vegetation.

Development of indicators of vegetation recovery based on time series analysis of SPOT Vegetation data

Science.gov (United States)

Lhermitte, S.; Tips, M.; Verbesselt, J.; Jonckheere, I.; Van Aardt, J.; Coppin, Pol

2005-10-01

Large-scale wild fires have direct impacts on natural ecosystems and play a major role in the vegetation ecology and carbon budget. Accurate methods for describing post-fire development of vegetation are therefore essential for the understanding and monitoring of terrestrial ecosystems. Time series analysis of satellite imagery offers the potential to quantify these parameters with spatial and temporal accuracy. Current research focuses on the potential of time series analysis of SPOT Vegetation S10 data (1999-2001) to quantify the vegetation recovery of large-scale burns detected in the framework of GBA2000. The objective of this study was to provide quantitative estimates of the spatio-temporal variation of vegetation recovery based on remote sensing indicators. Southern Africa was used as a pilot study area, given the availability of ground and satellite data. An automated technique was developed to extract consistent indicators of vegetation recovery from the SPOT-VGT time series. Reference areas were used to quantify the vegetation regrowth by means of Regeneration Indices (RI). Two kinds of recovery indicators (time and value- based) were tested for RI's of NDVI, SR, SAVI, NDWI, and pure band information. The effects of vegetation structure and temporal fire regime features on the recovery indicators were subsequently analyzed. Statistical analyses were conducted to assess whether the recovery indicators were different for different vegetation types and dependent on timing of the burning season. Results highlighted the importance of appropriate reference areas and the importance of correct normalization of the SPOT-VGT data.

Authentication of edible vegetable oils adulterated with used frying oil by Fourier Transform Infrared Spectroscopy.

Science.gov (United States)

Zhang, Qing; Liu, Cheng; Sun, Zhijian; Hu, Xiaosong; Shen, Qun; Wu, Jihong

2012-06-01

The application of Fourier Transform Infrared (FTIR) Spectroscopy to authenticate edible vegetable oils (corn, peanut, rapeseed and soybean oil) adulterated with used frying oil was introduced in this paper. The FTIR spectrum of oil was divided into 22 regions which corresponded to the constituents and molecular structures of vegetable oils. Samples of calibration set were classified into four categories for corn and peanut oils and five categories for rapeseed and soybean oils by cluster analysis. Qualitative analysis of validation set was obtained by discriminant analysis. Area ratio between absorption band 19 and 20 and wavenumber shift of band 19 were treated by linear regression for quantitative analysis. For four adulteration types, LODs of area ratio were 6.6%, 7.2%, 5.5%, 3.6% and wavenumber shift were 8.1%, 9.0%, 6.9%, 5.6%, respectively. The proposed methodology is a useful tool to authenticate the edible vegetable oils adulterated with used frying oil. Copyright © 2011 Elsevier Ltd. All rights reserved.

Majority Group Members' Negative Reactions to Future Demographic Shifts Depend on the Perceived Legitimacy of Their Status: Findings from the United States and Portugal.

Science.gov (United States)

Outten, H Robert; Lee, Timothy; Costa-Lopes, Rui; Schmitt, Michael T; Vala, Jorge

2018-01-01

Using concepts from social identity theory (Tajfel and Turner, 1979), we examined whether racial/ethnic majority group members' reactions to future demographic shifts is a function of the degree to which they perceive their ingroup's higher-status in society to be legitimate. In two studies, participants who varied in the degree to which they perceived their group's status to be legitimate were either exposed to real projections for 2060 (i.e., large decline in proportion of population that is the "majority" group), or fake projections for 2060-that resembled current figures (i.e., small decline). In Study 1, White Americans who perceived their status to be highly legitimate expressed greater intergroup threat, and negative feelings (anger and fear) toward minorities after exposure to projections with a large decline in the relative size of the White American population. In contrast, demographic shift condition had no effect on intergroup threat and negative feelings toward minorities among White Americans who perceived their status to be relatively illegitimate; negative feelings and threat remained low across both conditions. Similarly, in Study 2, ethnic Portuguese people in Portugal exposed to projections in which there was a large decline in the relative size of the ethnic Portuguese population experienced more intergroup threat and expressed a greater desire to engage in anti-immigration behaviors. The effect of demographic shift condition on intergroup threat and anti-immigration behaviors was stronger among ethnic Portuguese who perceived their status to be legitimate compared to ethnic Portuguese people who perceived their status to be relatively illegitimate. These results highlight that across different cultural contexts, majority group members' beliefs about the legitimacy of intergroup relations can affect their reactions to the prospect of increased diversity.

Investigating Strategies for Sustainable Vegetable Food Crop System in Three Agro Ecological Zones of the Humid Tropics Area of Cameroon

OpenAIRE

TATA NGOME, Precillia Ijang; AFARI-SEFA, Victor; NTSOMBOH-NTSEFONG, Godswill; OKOLLE, Justin; BILLA, Samuel Fru; MOMA, Crescence; ATEMKENG FONJI, Maureen; NGOME, Ajebesone Francis

2018-01-01

Vegetable cultivation remains an essential component of local people’s livelihoods. However, marked trend shifts in the varieties of vegetables due to large-scale commercial vegetable farming of exotic varieties in the broader market economy have resulted in the gradual disappearance of biodiversity involving vital species. The present study examined the situation of vegetable crop farming in three agro-ecological zones of Cameroon. Data were collected from a random sample of 235 respondents ...

Vegetation changes and human settlement of Easter Island during the last millennia: a multiproxy study of the Lake Raraku sediments

Science.gov (United States)

Cañellas-Boltà, Núria; Rull, Valentí; Sáez, Alberto; Margalef, Olga; Bao, Roberto; Pla-Rabes, Sergi; Blaauw, Maarten; Valero-Garcés, Blas; Giralt, Santiago

2013-07-01

Earlier palynological studies of lake sediments from Easter Island suggest that the island underwent a recent and abrupt replacement of palm-dominated forests by grasslands, interpreted as a deforestation by indigenous people. However, the available evidence is inconclusive due to the existence of extended hiatuses and ambiguous chronological frameworks in most of the sedimentary sequences studied. This has given rise to an ongoing debate about the timing and causes of the assumed ecological degradation and cultural breakdown. Our multiproxy study of a core recovered from Lake Raraku highlights the vegetation dynamics and environmental shifts in the catchment and its surroundings during the late Holocene. The sequence contains shorter hiatuses than in previously recovered cores and provides a more continuous history of environmental changes. The results show a long, gradual and stepped landscape shift from palm-dominated forests to grasslands. This change started c. 450 BC and lasted about two thousand years. The presence of Verbena litoralis, a common weed, which is associated with human activities in the pollen record, the significant correlation between shifts in charcoal influx, and the dominant pollen types suggest human disturbance of the vegetation. Therefore, human settlement on the island occurred c. 450 BC, some 1500 years earlier than is assumed. Climate variability also exerted a major influence on environmental changes. Two sedimentary gaps in the record are interpreted as periods of droughts that could have prevented peat growth and favoured its erosion during the Medieval Climate Anomaly and the Little Ice Age, respectively. At c. AD 1200, the water table rose and the former Raraku mire turned into a shallow lake, suggesting higher precipitation/evaporation rates coeval with a cooler and wetter Pan-Pacific AD 1300 event. Pollen and diatom records show large vegetation changes due to human activities c. AD 1200. Other recent vegetation changes also

Changes in forest productivity across Alaska consistent with biome shift.

Science.gov (United States)

Beck, Pieter S A; Juday, Glenn P; Alix, Claire; Barber, Valerie A; Winslow, Stephen E; Sousa, Emily E; Heiser, Patricia; Herriges, James D; Goetz, Scott J

2011-04-01

Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline. © 2011 Blackwell Publishing Ltd/CNRS.

/sup 1/H-NMR chemical shift imaging suitable for low field systems

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Etsuji; Onodera, Takashi; Shiono, Hidemi; Kohno, Hideki

1986-12-01

An echo-time encoding proton NMR chemical shift imaging proposed by Dixon is extended to be applicable to low filed systems. The method utilizes the small phase angle between magnetic vectors of water and lipid protons to decrease the signal decays with spin-spin relaxation. The inevitable phase error caused by the static field inhomogeneity is corrected by using phase images of phantom measured under the same conditions as the actual measurements. The experiments were carried out using CuSO/sub 4/ doped water and vegetable oil at 0.5 T. Two chemical shift images could be clearly resolved with only one scan when the field inhomogeneity was larger than the chemical shift difference.

Life stage, not climate change, explains observed tree range shifts

Czech Academy of Sciences Publication Activity Database

Máliš, F.; Kopecký, Martin; Petřík, Petr; Vladovič, J.; Merganič, J.; Vida, T.

2016-01-01

Roč. 22, č. 5 (2016), s. 1904-1914 ISSN 1354-1013 R&D Projects: GA MŠk(CZ) EE2.3.20.0267; GA ČR GPP505/10/P173 EU Projects: European Commission(XE) 278065 - LONGWOOD Institutional support: RVO:67985939 Keywords : elevational range shift * vegetation resurvey * temperate forests Subject RIV: EH - Ecology, Behaviour Impact factor: 8.502, year: 2016

Enhanced vegetation growth peak and its key mechanisms

Science.gov (United States)

Huang, K.; Xia, J.; Wang, Y.; Ahlström, A.; Schwalm, C.; Huntzinger, D. N.; Chen, J.; Cook, R. B.; Fang, Y.; Fisher, J. B.; Jacobson, A. R.; Michalak, A.; Schaefer, K. M.; Wei, Y.; Yan, L.; Luo, Y.

2017-12-01

It remains unclear that whether and how the vegetation growth peak has been shifted globally during the past three decades. Here we used two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in seasonal peak vegetation growth. The attribution of changes in peak growth to their driving factors was examined with several datasets. We demonstrated that the growth peak of global vegetation has been linearly increasing during the past three decades. About 65% of this trend is evenly explained by the expanding croplands (21%), rising atmospheric [CO2] (22%), and intensifying nitrogen deposition (22%). The contribution of expanding croplands to the peak growth trend was substantiated by measurements from eddy-flux towers, sun-induced chlorophyll fluorescence and a global database of plant traits, all of which demonstrated that croplands have a higher photosynthetic capacity than other vegetation types. The contribution of rising atmospheric [CO2] and nitrogen deposition are consistent with the positive response of leaf growth to elevated [CO2] (25%) and nitrogen addition (8%) from 346 manipulated experiments. The positive effect of rising atmospheric [CO2] was also well captured by 15 terrestrial biosphere models. However, most models underestimated the contributions of land-cover change and nitrogen deposition, but overestimated the positive effect of climate change.

Social Change and Language Shift: South Africa.

Science.gov (United States)

Kamwangamalu, Nkonko M.

2003-01-01

Examines language shift from majority African languages, such as Sotho, Xhosa, and Zulu to English in South Africa. Examines the extent to which sociopolitical changes that have taken place in South Africa have impacted everyday linguistic interaction and have contributed to language shift from the indigenous African language to English,…

Vegetation extraction from high-resolution satellite imagery using the Normalized Difference Vegetation Index (NDVI)

Science.gov (United States)

AlShamsi, Meera R.

2016-10-01

Over the past years, there has been various urban development all over the UAE. Dubai is one of the cities that experienced rapid growth in both development and population. That growth can have a negative effect on the surrounding environment. Hence, there has been a necessity to protect the environment from these fast pace changes. One of the major impacts this growth can have is on vegetation. As technology is evolving day by day, there is a possibility to monitor changes that are happening on different areas in the world using satellite imagery. The data from these imageries can be utilized to identify vegetation in different areas of an image through a process called vegetation detection. Being able to detect and monitor vegetation is very beneficial for municipal planning and management, and environment authorities. Through this, analysts can monitor vegetation growth in various areas and analyze these changes. By utilizing satellite imagery with the necessary data, different types of vegetation can be studied and analyzed, such as parks, farms, and artificial grass in sports fields. In this paper, vegetation features are detected and extracted through SAFIY system (i.e. the Smart Application for Feature extraction and 3D modeling using high resolution satellite ImagerY) by using high-resolution satellite imagery from DubaiSat-2 and DEIMOS-2 satellites, which provide panchromatic images of 1m resolution and spectral bands (red, green, blue and near infrared) of 4m resolution. SAFIY system is a joint collaboration between MBRSC and DEIMOS Space UK. It uses image-processing algorithms to extract different features (roads, water, vegetation, and buildings) to generate vector maps data. The process to extract green areas (vegetation) utilize spectral information (such as, the red and near infrared bands) from the satellite images. These detected vegetation features will be extracted as vector data in SAFIY system and can be updated and edited by end-users, such as

Radar for Measuring Soil Moisture Under Vegetation

Science.gov (United States)

Moghaddam, Mahta; Moller, Delwyn; Rodriguez, Ernesto; Rahmat-Samii, Yahya

2004-01-01

A two-frequency, polarimetric, spaceborne synthetic-aperture radar (SAR) system has been proposed for measuring the moisture content of soil as a function of depth, even in the presence of overlying vegetation. These measurements are needed because data on soil moisture under vegetation canopies are not available now and are necessary for completing mathematical models of global energy and water balance with major implications for global variations in weather and climate.

Spatiotemporal analysis of the effect of climate change on vegetation health in the Drakensberg Mountain Region of South Africa.

Science.gov (United States)

Mukwada, Geoffrey; Manatsa, Desmond

2018-05-24

The impact of climate change on mountain ecosystems has been in the spotlight for the past three decades. Climate change is generally considered to be a threat to ecosystem health in mountain regions. Vegetation indices can be used to detect shifts in ecosystem phenology and climate change in mountain regions while satellite imagery can play an important role in this process. However, what has remained problematic is determining the extent to which ecosystem phenology is affected by climate change under increasingly warming conditions. In this paper, we use climate and vegetation indices that were derived from satellite data to investigate the link between ecosystem phenology and climate change in the Namahadi Catchment Area of the Drakensberg Mountain Region of South Africa. The time series for climate indices as well as those for gridded precipitation and temperature data were analyzed in order to determine climate shifts, and concomitant changes in vegetation health were assessed in the resultant epochs using vegetation indices. The results indicate that vegetation indices should only be used to assess trends in climate change under relatively pristine conditions, where human influence is limited. This knowledge is important for designing climate change monitoring strategies that are based on ecosystem phenology and vegetation health.

Simulations of Vegetation Impacts on Arctic Climate

Science.gov (United States)

Bonfils, C.; Phillips, T. J.; Riley, W. J.; Post, W. M.; Torn, M. S.

2009-12-01

Because global warming disproportionately influences high-latitude climate, changes in arctic vegetation are in progress. These land-cover changes include redistribution of local vegetation types as well as northward migration of lower-latitude species in response to the increasing warming. The resulting displacement of low-lying tundra vegetation by shrubs and trees darkens the surface, thus accelerating regional warming. As participants in the U.S. Department of Energy IMPACTS Project, we are investigating the potential for abrupt arctic climatic change resulting from such variations in vegetation, among other mechanisms. To estimate the relative magnitudes of effects to be expected from changes in high-latitude land cover, we are conducting several numerical experiments with the Community Climate System Model (CCSM). These experiments include: 1) A “present-day-climate” control experiment with current atmospheric greenhouse-gas concentrations and climatological monthly sea surface temperatures and sea ice extents prescribed, and with “standard” CLM plant functional types (PFTs) specified; 2) A “changed-vegetation-type” experiment that is the same as 1), except that the “standard” PFTs are augmented by additional vegetation types (forbs, sedges, shrubs, mosses, and lichens) that are not presently represented in CLM. This experiment will require information on the location, fractional cover, and physiological parameterizations of these new PFTs. 3) A “changed-vegetation-extent experiment” that is the same as 2), except that the spatial extents of selected PFTs (e.g. shrubs or boreal forest PFTs) are shifted northward from their present locations in the CLM. We will report on the atmospheric climate and land-surface feedbacks associated with these vegetation changes, with emphasis on local and regional surface energy and moisture fluxes and near-surface temperature, humidity, and clouds. Acknowledgments This work was performed under the auspices

Terrestrial transect study on driving mechanism of vegetation changes

Institute of Scientific and Technical Information of China (English)

2008-01-01

In terms of Chinese climate-vegetation model based on the classification of plant functional types, to- gether with climatic data from 1951 to 1980 and two future climatic scenarios (SRES-A2 and SRES-B2) in China from the highest and the lowest emission scenarios of greenhouse gases, the distribution patterns of vegetation types and their changes along the Northeast China Transect (NECT) and the North-South Transect of Eastern China (NSTEC) were simulated in order to understand the driving mechanisms of vegetation changes under climatic change. The results indicated that the vegetation distribution patterns would change significantly under future climate, and the major factors driving the vegetation changes were water and heat. However, the responses of various vegetation types to the changes in water and heat factors were obviously different. The vegetation changes were more sensi- tive to heat factors than to water factors. Thus, in the future climate warming will significantly affect vegetation distribution patterns.

ISLSCP II Potential Natural Vegetation Cover

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set was developed to describe the state of the global land cover in terms of 15 major vegetation types, plus water, before alteration by humans....

South Korea's entry to the global food economy: shifts in consumption of food between 1998 and 2009.

Science.gov (United States)

Lee, Haeng-Shin; Duffey, Kiyah J; Popkin, Barry M

2012-01-01

Korea has undergone a major opening of its food markets and economy in the past decade. Little is understood about the impact of these shifts on the diet of Koreans. This analysis studies the shifts in consumption of foods between 1998 and 2009 to provide a thorough understanding of the transition and insights into directions in the next decades in Korea. Data are from the Korea National Health and Nutrition Examination Survey (KNHANES). The sample used was a nationally representative sample of individuals age ≥2 in 1998 and 2009 (n=10,267 and 9,264, respectively). The data was corrected for seasonality, and the original raw food data was regrouped into 53 food groups. SAS was used to adjust for design effects and weight. Despite a decade of efforts to increase whole grains intake, and fruit and vegetable intake, the mean intake of whole grains increased only a small amount (16 kcal/person/day); however, the proportion consuming any whole grains doubled from 24% to 46.3%. Rice declined significantly, and several important less healthful food trends emerged: total alcohol intake increased from 39 kcal/person/day to 82 kcal/person/day. Also, energy from sugar-sweetened beverages increased among teens and energy from tea and coffee increased among adults. Remarkably, compared to other Asian countries and a general worldwide trend, vegetable intake remained relative high in South Korea during this last decade while fat energy increased modestly from relative low levels. Dynamic causes of these trends and the government's response are discussed.

Interannual water-level fluctuations and the vegetation of prairie potholes: Potential impacts of climate change

Science.gov (United States)

van der Valk, Arnold; Mushet, David M.

2016-01-01

Mean water depth and range of interannual water-level fluctuations over wet-dry cycles in precipitation are major drivers of vegetation zone formation in North American prairie potholes. We used harmonic hydrological models, which require only mean interannual water depth and amplitude of water-level fluctuations over a wet–dry cycle, to examine how the vegetation zones in a pothole would respond to small changes in water depth and/or amplitude of water-level fluctuations. Field data from wetlands in Saskatchewan, North Dakota, and South Dakota were used to parameterize harmonic models for four pothole classes. Six scenarios in which small negative or positive changes in either mean water depth, amplitude of interannual fluctuations, or both, were modeled to predict if they would affect the number of zones in each wetland class. The results indicated that, in some cases, even small changes in mean water depth when coupled with a small change in amplitude of water-level fluctuations can shift a prairie pothole wetland from one class to another. Our results suggest that climate change could alter the relative proportion of different wetland classes in the prairie pothole region.

Using management to address vegetation stress related to land-use and climate change

Science.gov (United States)

Middleton, Beth A.; Boudell, Jere; Fisichelli, Nicholas

2017-01-01

While disturbances such as fire, cutting, and grazing can be an important part of the conservation of natural lands, some adjustments to management designed to mimic natural disturbance may be necessary with ongoing and projected climate change. Stressed vegetation that is incapable of regeneration will be difficult to maintain if adults are experiencing mortality, and/or if their early life-history stages depend on disturbance. A variety of active management strategies employing disturbance are suggested, including resisting, accommodating, or directing vegetation change by manipulating management intensity and frequency. Particularly if land-use change is the main cause of vegetation stress, amelioration of these problems using management may help vegetation resist change (e.g. strategic timing of water release if a water control structure is available). Managers could direct succession by using management to push vegetation toward a new state. Despite the historical effects of management, some vegetation change will not be controllable as climates shift, and managers may have to accept some of these changes. Nevertheless, proactive measures may help managers achieve important conservation goals in the future.

Dissociation from beloved unhealthy brands decreases preference for and consumption of vegetables.

Science.gov (United States)

Trump, Rebecca K; Connell, Paul M; Finkelstein, Stacey R

2015-09-01

Many people form strong bonds with brands, including those for unhealthy foods. Thus, prompting people to dissociate from beloved but unhealthy food brands is an intuitively appealing means to shift consumption away from unhealthy options and toward healthy options. Contrary to this position, we demonstrate that dissociating from unhealthy but beloved brands diminishes people's interest in consuming vegetables because the dissociation depletes self-regulatory resources. Across three experimental studies, we manipulate dissociation from two beloved brands both implicitly (studies 1-2) and explicitly (study 3) and observe effects on both preference for vegetables (studies 2-3) and actual vegetable consumption (study 1). In study 1, participants consumed fewer vegetables following dissociation from (vs. association with) a beloved candy brand. Study 2 demonstrates that the effect of depletion on preference for vegetables is more pronounced for those who strongly identify with the brand, as these individuals are most depleted by the dissociation attempt. Finally, study 3 illustrates that the difficulty experienced when trying to dissociate from beloved brands drives the observed effects on vegetable preference and consumption for those who strongly (vs. weakly) identify with the brand. Copyright © 2015 Elsevier Ltd. All rights reserved.

Vegetation studies on Vandenberg Air Force Base, California

Science.gov (United States)

Schmalzer, Paul A.; Hickson, Diana E.; Hinkle, C. Ross

1988-01-01

Vandenburg Air Force Base, located in coastal central California with an area of 98,400 ac, contains resources of considerable biological significance. Available information on the vegetation and flora of Vandenburg is summarized and new data collected in this project are presented. A bibliography of 621 references dealing with vegetation and related topics related to Vanderburg was compiled from computer and manual literature searches and a review of past studies of the base. A preliminary floristic list of 642 taxa representing 311 genera and 80 families was compiled from past studies and plants identified in the vegetation sampling conducted in this project. Fifty-two special interest plant species are known to occur or were suggested to occur. Vegetation was sampled using permanent plots and transects in all major plant communities including chaparral, Bishop pine forest, tanbark oak forest, annual grassland, oak woodland, coastal sage scrub, purple sage scrub, coastal dune scrub, coastal dunes, box elder riparian woodland, will riparian woodland, freshwater marsh, salt marsh, and seasonal wetlands. Comparison of the new vegetation data to the compostie San Diego State University data does not indicate major changes in most communities since the original study. Recommendations are made for additional studies needed to maintain and extend the environmental data base and for management actions to improve resource protection.

Shrubs in the cold : interactions between vegetation, permafrost and climate in Siberian tundra

NARCIS (Netherlands)

Blok, D.

2011-01-01

The Arctic is experiencing strong increases in air temperature during the last decades. High-latitude tundra regions are very responsive to changes in temperature and may cause a shift in tundra vegetation composition towards greater dominance of deciduous shrubs. With increasing deciduous shrub

Shift work-related health problems in

Directory of Open Access Journals (Sweden)

S. Khavaji

2010-04-01

Full Text Available Background and aimsShift work is a major feature of working life that affects diverse aspects of human life. The main purposes of this study were to investigate shift work-related health problems and their risk factors among workers of "12-hour shift" schedule.MethodsThis cross-sectional study was carried out at 8 petrochemical industries in Asalooyeh area. Study population consisted of 1203 workers including 549 shift worker (46% and 654 day worker (54%. Data on personal details, shift schedule and adverse effects of shift work werecollected by anonymous questionnaire. Statistical analyses were performed using SPSS, version 11.5. The level of significance was set at 5%.ResultsAlthough, the results showed that health problems among shift workers was more prevalent than day workers, but the differences were just significant in gastrointestinal and musculoskeletal disorders (p<0.05. Multiple linear regressions indicated that in addition to shift working, other variants such as long work hours, type of employment, second job, number of children and job title were associated with health problems.ConclusionPrevalence rates of gastrointestinal and musculoskeletal problems among shift workers were significantly higher than that of day workers. Although, working in shift system was the main significant factor associated with the reported problems, but other demographic andwork variables were also found to have association.

South Korea’s entry to the global food economy: Shifts in consumption of food between 1998 and 2009

Science.gov (United States)

Lee, Haeng-Shin; Duffey, Kiyah J.; Popkin, Barry M.

2013-01-01

Korea has undergone a major opening of its food markets and economy in the past decade. Little is understood about the impact of these shifts on the diet of Koreans. This analysis studies the shifts in consumption of foods between 1998 and 2009 to provide a thorough understanding of the transition and insights into directions in the next decades in Korea. Data are from the Korea National Health and Nutrition Examination Survey (KNHANES), a nationally representative sample of individuals age ≥2 in 1998 and 2009 (n=10,267 and 9,264, respectively). The data are corrected for seasonality, and the original raw food data are regrouped into 53 food groups. SAS is used to adjust for design effects and weight the results. Despite a decade of efforts to increase whole grains intake and fruit and vegetable intake, the mean intake of whole grains increased only a small amount (+16 kcal/person/d); however, the proportion consuming any whole grains doubled from 24% to 46.3%. Rice declined significantly, and several important less healthful food trends emerged: total Alcohol intake increased from 39 kcal/person/d to 82 kcal/person/d. Also, energy from Sugar-Sweetened Beverages increased among teens and energy from Tea & Coffee increased among adults. Remarkably, compared to other Asian countries and a general worldwide trend, vegetable intake remained very high in South Korea during this last decade while fat energy increased modestly from very low levels. Dynamic causes of these trends and the government’s response are discussed. PMID:23017321

Food and nutrient intake among workers with different shift systems.

Science.gov (United States)

Hemiö, Katri; Puttonen, Sampsa; Viitasalo, Katriina; Härmä, Mikko; Peltonen, Markku; Lindström, Jaana

2015-07-01

Over 20% of employees in Europe work in shifts. Shift work increases the risk for chronic diseases, but a healthy lifestyle may attenuate the adverse effect of shift work. The aim of this study was to explore food and nutrient intake differences between working time groups. The participants were 1478 employees (55% of men) of an airline divided into three working time groups: day work (n=608), shift work without in-flight work (n=541) and in-flight work (n=329). Measures included laboratory tests, physical measurements, a questionnaire, and food and nutrient intake estimations by a validated 16-item food intake questionnaire. Shift working men were less likely to consume vegetables (p<0.001) and fruits (p=0.049) daily than male day and in-flight workers. In women, energy intake from saturated fat was higher among shift workers compared with day workers (12.6 vs 12.2 E%, p=0.023). In older female participants, energy intake from fat and saturated fat was higher in the shift work and in-flight work groups than in the day work group (p<0.001). In this study, shift work and working environment were associated with dietary habits, and this association was not explained by other characteristics such as workers' educational level. Shift workers' increased risk for chronic diseases should be taken into account and lifestyle counselling including advice in nutrition should be incorporated in routine occupational healthcare of shift workers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Vegetation responses to sagebrush-reduction treatments measured by satellites

Science.gov (United States)

Johnston, Aaron; Beever, Erik; Merkle, Jerod A.; Chong, Geneva W.

2018-01-01

Time series of vegetative indices derived from satellite imagery constitute tools to measure ecological effects of natural and management-induced disturbances to ecosystems. Over the past century, sagebrush-reduction treatments have been applied widely throughout western North America to increase herbaceous vegetation for livestock and wildlife. We used indices from satellite imagery to 1) quantify effects of prescribed-fire, herbicide, and mechanical treatments on vegetative cover, productivity, and phenology, and 2) describe how vegetation changed over time following these treatments. We hypothesized that treatments would increase herbaceous cover and accordingly shift phenologies towards those typical of grass-dominated systems. We expected prescribed burns would lead to the greatest and most-prolonged effects on vegetative cover and phenology, followed by herbicide and mechanical treatments. Treatments appeared to increase herbaceous cover and productivity, which coincided with signs of earlier senescence − signals expected of grass-dominated systems, relative to sagebrush-dominated systems. Spatial heterogeneity for most phenometrics was lower in treated areas relative to controls, which suggested treatment-induced homogenization of vegetative communities. Phenometrics that explain spring migrations of ungulates mostly were unaffected by sagebrush treatments. Fire had the strongest effect on vegetative cover, and yielded the least evidence for sagebrush recovery. Overall, treatment effects were small relative to those reported from field-based studies for reasons most likely related to sagebrush recovery, treatment specification, and untreated patches within mosaicked treatment applications. Treatment effects were also small relative to inter-annual variation in phenology and productivity that was explained by temperature, snowpack, and growing-season precipitation. Our results indicated that cumulative NDVI, late-season phenometrics, and spatial

Limiting factors for vegetation development during the early late glacial in Denmark

DEFF Research Database (Denmark)

Mortensen, Morten Fischer; Odgaard, Bent Vad; Jessen, Cathrine

Slotseng, a small basin in southern Jutland, is the first Danish site with a bio- and chronostratigraphy that unambiguously reflects the environment of the earliest late glacial, the Bølling period. Results of pollen and macrofossil analyses show that the vegetation of the Bølling and Older Dryas...... periods at Slotseng was dominated by Betula nana and Dryas octopetala and associated with many herbs of open habitats. Late-glacial pollen records are frequently interpreted only in the context of climate change. However, the forcing mechanisms of vegetational change may shift over time between e...... to climate change suggests that other factors limited vegetational development. These factors included soil instability, aridity and low soil nitrogen.. This study highlights the multitude of climatic, physical, chemical and biological interactions important for the formation of pollen records of late...

Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

Energy Technology Data Exchange (ETDEWEB)

Peace, Gerald (Jerry) L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

2004-11-01

A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

Quantifying Regional Vegetation Changes in China During Three Contrasting Warming Intervals since the Last Glacial Maximum

Science.gov (United States)

Li, Q.; Wu, H.; Yu, Y.; Sun, A.; Luo, Y.

2017-12-01

Reconstructing patterns of past vegetation change on a large-scale facilitates a better understanding of the interactions and feedbacks between climate change and the terrestrial biosphere. In addition, reducing the uncertainty in predictions of vegetation change under global warming highlights the importance of reconstructing vegetation patterns during past warming intervals. Here, we present a quantitative regional vegetation reconstruction for China during three intervals: Last Glacial Maximum (LGM, 18±2 14C kyr B.P.), early Holocene (8.5±0.5 14C kyr B.P.), and mid-Holocene (6±0.5 14C kyr B.P.). The biomization method, based on 249 pollen records, was used for the reconstructions. The results demonstrate that during the LGM, steppe and desert expanded eastwards and southwards, reaching the present-day temperate deciduous forest (TEDE) zone, and dominated northern China. In contrast, the forest in Eastern China underwent a substantial southwards retreat and the percentage of forest-type sites was at a minimum. In addition, the warm mixed forest (WAMF) and TEDE shifted southwards of 10° N relative to the present-day, and tropical seasonal rain forest (TSFO) was almost absent. At the same time, the forest-steppe boundary shifted southwards to near the middle and lower reaches of Yangtze River. For the early Holocene and mid-Holocene, the TSFO, WAMF, and TEDE shifted northwards by 2-5° relative to today, and the percentage of forest sites increased and reached a maximum in the mid-Holocene. The slight expansion of forest from the early Holocene to the mid-Holocene caused the forest-steppe boundary to shift northwestwards to near the present-day 300 mm isohyet by the mid-Holocene. Our results also indicate that climatic warming since the LGM, which strengthened the East Asian summer monsoon, favored the development of forest in China. This is potentially an important finding for evaluating the possible response of forest in China to future global warming.

Comparative Drought Responses of Quercus ilex L. and Pinus sylvestris L. in a Montane Forest Undergoing a Vegetation Shift

Directory of Open Access Journals (Sweden)

David Aguadé

2015-07-01

Full Text Available Different functional and structural strategies to cope with water shortage exist both within and across plant communities. The current trend towards increasing drought in many regions could drive some species to their physiological limits of drought tolerance, potentially leading to mortality episodes and vegetation shifts. In this paper, we study the drought responses of Quercus ilex and Pinus sylvestris in a montane Mediterranean forest where the former species is replacing the latter in association with recent episodes of drought-induced mortality. Our aim was to compare the physiological responses to variations in soil water content (SWC and vapor pressure deficit (VPD of the two species when living together in a mixed stand or separately in pure stands, where the canopies of both species are completely exposed to high radiation and VPD. P. sylvestris showed typical isohydric behavior, with greater losses of stomatal conductance with declining SWC and greater reductions of stored non-structural carbohydrates during drought, consistent with carbon starvation being an important factor in the mortality of this species. On the other hand, Q. ilex trees showed a more anisohydric behavior, experiencing more negative water potentials and higher levels of xylem embolism under extreme drought, presumably putting them at higher risk of hydraulic failure. In addition, our results show relatively small changes in the physiological responses of Q. ilex in mixed vs. pure stands, suggesting that the current replacement of P. sylvestris by Q. ilex will continue.

Integrated ecological and chemical food web accumulation modeling explains PAH temporal trends during regime shifts in a shallow lake.

Science.gov (United States)

Kong, Xiangzhen; He, Wei; Qin, Ning; Liu, Wenxiu; Yang, Bin; Yang, Chen; Xu, Fuliu; Mooij, Wolf M; Koelmans, Albert A

2017-08-01

Shallow lakes can switch suddenly from a turbid situation with high concentrations of phytoplankton and other suspended solids to a vegetated state with clear water, and vice versa. These alternative stable states may have a substantial impact on the fate of hydrophobic organic compounds (HOCs). Models that are fit to simulate impacts from these complex interactions are scarce. We developed a contaminant fate model which is linked to an ecosystem model (PCLake) for shallow lakes. This integrated model was successful in simulating long-term dynamics (1953-2012) of representative polycyclic aromatic hydrocarbons (PAHs) in the main biotic and abiotic components in a large shallow lake (Chaohu in China), which has undergone regime shifts in this period. Historical records from sediment cores were used to evaluate the model. The model revealed that regime shifts in shallow lakes had a strong impact on the fate of less hydrophobic compounds due to the large storage capacity of macrophytes, which accumulated up to 55.6% of phenanthrene in the clear state. The abrupt disappearance of macrophytes after the regime shift resulted in a sudden change in phenanthrene distribution, as the sediment became the major sink. For more hydrophobic compounds such as benzo(a)pyrene, the modeled impact of the regime shift was negligible for the whole environment, yet large for biotic compartments. This study is the first to provide a full mechanistic analysis of the impact of regime shifts on the fate of PAHs in a real lake ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.

The 2005 and 2012 major drought events in Iberia: monitoring vegetation dynamics and crop yields using satellite data.

Science.gov (United States)

Gouveia, Célia M.; Trigo, Ricardo M.

2014-05-01

The Iberian Peninsula is recurrently affected by drought episodes and therefore by the adverse effects associated that range from severe water shortages to economic losses and related social impacts. During the hydrological years of 2004/2005 and 2011/2012, Iberia was hit by two of the worst drought episodes ever recording in this semi-arid region (Garcia-Herrera at al., 2007; Trigo et al., 2013). These two drought episodes were extreme in both its magnitude and spatial extent. A tendency towards a drier Mediterranean for the period 1970-2010 in comparison with 1901-70 has been identified (Hoerling et al., 2012), reinforcing the need for a continuous monitoring of vegetation stress and reliable estimates of the drought impacts. The strong effect of water scarcity on vegetation dynamics is well documented in Mediterranean and other semi-arid regions. Despite the usual link established between the decrease of vegetation greenness and the lack of precipitation during a considerably long period, the impact on vegetation activity may be amplified by other climatic anomalies, such as high temperature, high wind, and low relative humidity. The recent availability of consistent satellite imagery covering large regions over long periods of time has progressively reinforced the role of remote sensing in environmental studies, in particular in those related to drought episodes (e.g. Gouveia et al., 2009). The aim of the present work is to assess and monitor the cumulative impact over time of drought conditions on vegetation over Iberian Peninsula. For this purpose we have used the regional fields of the Normalized Difference Vegetation Index (NDVI) as obtained from the VEGETATION-SPOT5 instrument, from 1999 to 2013. The entire 15-yr long period was analysed, but particular attention was devoted to the two extreme drought episodes of 2004-2005 and 2011-2012. During the hydrological years of 2004-2005 and 2011-2012 drought episodes negative anomalies of NDVI were observed over

Associations between shift schedule characteristics with sleep, need for recovery, health and performance measures for regular (semi-)continuous 3-shift systems.

Science.gov (United States)

van de Ven, Hardy A; Brouwer, Sandra; Koolhaas, Wendy; Goudswaard, Anneke; de Looze, Michiel P; Kecklund, Göran; Almansa, Josue; Bültmann, Ute; van der Klink, Jac J L

2016-09-01

In this cross-sectional study associations were examined between eight shift schedule characteristics with shift-specific sleep complaints and need for recovery and generic health and performance measures. It was hypothesized that shift schedule characteristics meeting ergonomic recommendations are associated with better sleep, need for recovery, health and performance. Questionnaire data were collected from 491 shift workers of 18 companies with 9 regular (semi)-continuous shift schedules. The shift schedule characteristics were analyzed separately and combined using multilevel linear regression models. The hypothesis was largely not confirmed. Relatively few associations were found, of which the majority was in the direction as expected. In particular early starts of morning shifts and many consecutive shifts seem to be avoided. The healthy worker effect, limited variation between included schedules and the cross-sectional design might explain the paucity of significant results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison and Validation of Long Time Serial Global GEOV1 and Regional Australian MODIS Fractional Vegetation Cover Products Over the Australian Continent

Directory of Open Access Journals (Sweden)

Yanling Ding

2015-05-01

Full Text Available Fractional vegetation cover (FVC is one of the most critical parameters in monitoring vegetation status. Comprehensive assessment of the FVC products is critical for their improvement and use in land surface models. This study investigates the performances of two major long time serial FVC products: GEOV1 and Australian MODIS. The spatial and temporal consistencies of these products were compared during the 2000–2012 period over the main biome types across the Australian continent. Their accuracies were validated by 443 FVC in-situ measurements during the 2011–2012 period. Our results show that there are strong correlations between the GEOV1 and Australian MODIS FVC products over the main Australian continent while they exhibit large differences and uncertainties in the coastal regions covered by dense forests. GEOV1 and Australian MODIS describe similar seasonal variations over the main biome types with differences in magnitude, while Australian MODIS exhibit unstable temporal variations over grasslands and shifted seasonal variations over evergreen broadleaf forests. The GEOV1 and Australian MODIS products overestimate FVC values over the biome types with high vegetation density and underestimate FVC in sparsely vegetated areas and grasslands. Overall, the GEOV1 and Australian MODIS FVC products agree with in-situ FVC values with a RMSE around 0.10 over the Australian continent.

A multi-model analysis of risk of ecosystem shifts under climate change

International Nuclear Information System (INIS)

Warszawski, Lila; Ostberg, Sebastian; Frieler, Katja; Lucht, Wolfgang; Schaphoff, Sibyll; Buechner, Matthias; Piontek, Franziska; Friend, Andrew; Keribin, Rozenn; Rademacher, Tim Tito; Beerling, David; Lomas, Mark; Cadule, Patricia; Ciais, Philippe; Clark, Douglas B; Kahana, Ron; Ito, Akihiko; Nishina, Kazuya; Kleidon, Axel; Pavlick, Ryan

2013-01-01

Climate change may pose a high risk of change to Earth’s ecosystems: shifting climatic boundaries may induce changes in the biogeochemical functioning and structures of ecosystems that render it difficult for endemic plant and animal species to survive in their current habitats. Here we aggregate changes in the biogeochemical ecosystem state as a proxy for the risk of these shifts at different levels of global warming. Estimates are based on simulations from seven global vegetation models (GVMs) driven by future climate scenarios, allowing for a quantification of the related uncertainties. 5–19% of the naturally vegetated land surface is projected to be at risk of severe ecosystem change at 2 ° C of global warming (ΔGMT) above 1980–2010 levels. However, there is limited agreement across the models about which geographical regions face the highest risk of change. The extent of regions at risk of severe ecosystem change is projected to rise with ΔGMT, approximately doubling between ΔGMT = 2 and 3 ° C, and reaching a median value of 35% of the naturally vegetated land surface for ΔGMT = 4 °C. The regions projected to face the highest risk of severe ecosystem changes above ΔGMT = 4 °C or earlier include the tundra and shrublands of the Tibetan Plateau, grasslands of eastern India, the boreal forests of northern Canada and Russia, the savanna region in the Horn of Africa, and the Amazon rainforest. (letter)

Response of Vegetation on Gravel Bars to Management Measures and Floods: Case Study From the Czech Republic

Directory of Open Access Journals (Sweden)

Eremiášová Renata

2014-08-01

Full Text Available This article investigates response of vegetation on gravel bars to management measures and floods. The management measures consisted of the partial removal of gravel and vegetation cover, and were applied to six gravel bars on the Ostravice River, Czech Republic. Unexpected floods occu-rred in 2010, with the amplitude of 5- to 50-year repetition. Research of vegetation on the gravel bars consisted of vegetation survey before the management works; the monitoring of vegetation development over the following year and the verification of the relationships of species diversity, successional stages and the biotope conditions with the help of multivariate analysis (detrended correspondence analysis. Vegetation on the gravel bars was at different successional stages, and had higher diversity and vegetation cover before the management measures and floods. The mul-tivariate analysis revealed a shift toward initial successional stages with high demand on moisture, temperature and light after both management measures and floods.

Direct and terrestrial vegetation-mediated effects of environmental change on aquatic ecosystem processes

Science.gov (United States)

Becky A. Ball; John S. Kominoski; Heather E. Adams; Stuart E. Jones; Evan S. Kane; Terrance D. Loecke; Wendy M. Mahaney; Jason P. Martina; Chelse M. Prather; Todd M.P. Robinson; Christopher T. Solomon

2010-01-01

Global environmental changes have direct effects on aquatic ecosystems, as well as indirect effects through alterations of adjacent terrestrial ecosystem structure and functioning. For example, shifts in terrestrial vegetation communities resulting from global changes can affect the quantity and quality of water, organic matter, and nutrient inputs to aquatic...

Map of mixed prairie grassland vegetation, Rocky Flats, Colorado

Energy Technology Data Exchange (ETDEWEB)

Clark, S J.V.; Webber, P J; Komarkova, V; Weber, W A

1980-01-01

A color vegetation map at the scale of 1:12,000 of the area surrounding the Rocky Flats, Rockwell International Plant near Boulder, Colorado, provides a permanent record of baseline data which can be used to monitor changes in both vegetation and environment and thus to contribute to future land management and land-use policies. Sixteen mapping units based on species composition were identified, and characterized by two 10-m/sup 2/ vegetation stands each. These were grouped into prairie, pasture, and valley side on the basis of their species composition. Both the mapping units and these major groups were later confirmed by agglomerative clustering analysis of the 32 vegetation stands on the basis of species composition. A modified Bray and Curtis ordination was used to determine the environmental factor complexes controlling the distribution of vegetation at Rocky flats. Recommendations are made for future policies of environmental management and predictions of the response to environmental change of the present vegetation at the Rocky Flats site.

Regime shifts, resilience and recovery of a cod stock

DEFF Research Database (Denmark)

Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

2010-01-01

In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...

Vegetable Grafting: The Implications of a Growing Agronomic Imperative for Vegetable Fruit Quality and Nutritive Value

Directory of Open Access Journals (Sweden)

Marios C. Kyriacou

2017-05-01

Full Text Available Grafting has become an imperative for intensive vegetable production since chlorofluorocarbon-based soil fumigants were banned from use on grounds of environmental protection. Compelled by this development, research into rootstock–scion interaction has broadened the potential applications of grafting in the vegetable industry beyond aspects of soil phytopathology. Grafting has been increasingly tapped for cultivation under adverse environs posing abiotic and biotic stresses to vegetable crops, thus enabling expansion of commercial production onto otherwise under-exploited land. Vigorous rootstocks have been employed not only in the open field but also under protected cultivation where increase in productivity improves distribution of infrastructural and energy costs. Applications of grafting have expanded mainly in two families: the Cucurbitaceae and the Solanaceae, both of which comprise major vegetable crops. As the main drives behind the expansion of vegetable grafting have been the resistance to soilborne pathogens, tolerance to abiotic stresses and increase in yields, rootstock selection and breeding have accordingly conformed to the prevailing demand for improving productivity, arguably at the expense of fruit quality. It is, however, compelling to assess the qualitative implications of this growing agronomic practice for human nutrition. Problems of impaired vegetable fruit quality have not infrequently been associated with the practice of grafting. Accordingly, the aim of the current review is to reassess how the practice of grafting and the prevalence of particular types of commercial rootstocks influence vegetable fruit quality and, partly, storability. Physical, sensorial and bioactive aspects of quality are examined with respect to grafting for watermelon, melon, cucumber, tomato, eggplant, and pepper. The physiological mechanisms at play which mediate rootstock effects on scion performance are discussed in interpreting the

Vegetation Activity Trend and Its Relationship with Climate Change in the Three Gorges Area, China

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Guifeng Han

2013-01-01

Full Text Available Based on SPOT/VGT NDVI time series images from 1999 to 2009 in the Three Gorges Area (TGA, we detected vegetation activity and trends using two methods, the Mann-Kendall and Slope tests. The relationships between vegetation activity trends and annual average temperature and annual total precipitation were analyzed using observational data in seven typical meteorological stations. Vegetation activity presents a distinctive uptrend during the study period, especially in Fengjie, Yunyang, Wushan, Wuxi, and Badong counties located in the midstream of the Three Gorges Reservoir. However, in the Chongqing major area (CMA and its surrounding areas and Fuling, Yichang, and part of Wanzhou, vegetation activity shows a decreasing trend as a result of urban expansion. The NDVI has two fluctuation troughs in 2004 and 2006. The annual mean temperature presents a slight overall upward trend, but the annual total precipitation does not present a significant trend. And they almost have no significant correlations with the NDVI. Therefore, temperature and precipitation are not major influences on vegetation activity change. Instead, increasing vegetation cover benefits from a number of environment protection policies and management, and ecological construction is a major factor resulting in the upward trend. In addition, resettlement schemes mitigate the impact of human activity on vegetation activity.

PROBLEMS IN VEGETATION MONITORING IN NATURE MANAGEMENT PRACTICE: TWO CASE STUDIES

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I. DE RONDE

2007-04-01

Full Text Available One of the major requirements of the monitoring of vegetation is the comparability of data between years. Therefore, a proper sampling scheme is essential. However, through the years, in nature management practice lots of data collected without a primary monitoring goal. Afterwards, it often seems very valuable to include these older data in the analysis for several reasons. In two examples from military ranges in the Netherlands, two of the problems which can be met with in comparing unequivalent or biased data in monitoring are shown. In the first example, the frequency of grassland species in two sets of relevés is examined. A solution is presented for the overrepresentation of relevés from one or more vegetation types from the first year, based on the area of the vegetation types on the vegetation map of this same year. In the second example, two sequential vegetation maps are compared. A major problem is often the thematic incongruence of sequential vegetation maps. Afterwards, this can only be resolved by upscaling one or both maps. It is concluded that the use of old data for monitoring purposes can be very valuable, but that this often calls for creative data handling, in which GIS and modern computer programmes are very helpful.

Majority Group Members' Negative Reactions to Future Demographic Shifts Depend on the Perceived Legitimacy of Their Status: Findings from the United States and Portugal

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H. Robert Outten

2018-02-01

Full Text Available Using concepts from social identity theory (Tajfel and Turner, 1979, we examined whether racial/ethnic majority group members' reactions to future demographic shifts is a function of the degree to which they perceive their ingroup's higher-status in society to be legitimate. In two studies, participants who varied in the degree to which they perceived their group's status to be legitimate were either exposed to real projections for 2060 (i.e., large decline in proportion of population that is the “majority” group, or fake projections for 2060—that resembled current figures (i.e., small decline. In Study 1, White Americans who perceived their status to be highly legitimate expressed greater intergroup threat, and negative feelings (anger and fear toward minorities after exposure to projections with a large decline in the relative size of the White American population. In contrast, demographic shift condition had no effect on intergroup threat and negative feelings toward minorities among White Americans who perceived their status to be relatively illegitimate; negative feelings and threat remained low across both conditions. Similarly, in Study 2, ethnic Portuguese people in Portugal exposed to projections in which there was a large decline in the relative size of the ethnic Portuguese population experienced more intergroup threat and expressed a greater desire to engage in anti-immigration behaviors. The effect of demographic shift condition on intergroup threat and anti-immigration behaviors was stronger among ethnic Portuguese who perceived their status to be legitimate compared to ethnic Portuguese people who perceived their status to be relatively illegitimate. These results highlight that across different cultural contexts, majority group members' beliefs about the legitimacy of intergroup relations can affect their reactions to the prospect of increased diversity.

Changes in climatic conditions, vegetation cover and erosion during the Holocene in southeast Spain

Energy Technology Data Exchange (ETDEWEB)

Bellin, N.; Vanacker, V.

2009-07-01

The present-day landscape in Southeast Spain is the result of a long occupation history. To have a better understanding of the impact of human societies on soil degradation, we analysed the main shifts in vegetation cover, climate and human occupation for the last 12000 years. Our analyses use recently published information from continental and marine pollen series. The data suggest that climatic factors appear to be important driving factors of vegetation degradation induced by an increased aridity that is already recorded at about 5000 years ago. (Author) 19 refs.

Changes in climatic conditions, vegetation cover and erosion during the Holocene in southeast Spain

International Nuclear Information System (INIS)

Bellin, N.; Vanacker, V.

2009-01-01

The present-day landscape in Southeast Spain is the result of a long occupation history. To have a better understanding of the impact of human societies on soil degradation, we analysed the main shifts in vegetation cover, climate and human occupation for the last 12000 years. Our analyses use recently published information from continental and marine pollen series. The data suggest that climatic factors appear to be important driving factors of vegetation degradation induced by an increased aridity that is already recorded at about 5000 years ago. (Author) 19 refs.

Assessment of hydrological regimes for vegetation on riparian wetlands in Han River Basin, Korea

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Jaewon Kwak

2017-01-01

Full Text Available Hydrological regimes are regarded as one of the major determinants for wetland ecosystems, for they influence species composition, succession, productivity, and stability of vegetation communities. Since Korea launched the Four Major River Restoration Project in 2007, the water regimes of many of the riparian wetlands have changed, that is potentially affecting vegetation properties. For ecological conservation and management, it is important to connect hydrological characteristics and vegetation properties. The objective of this study is to investigate the influence of hydrological regimes on vegetation community, and develop a methodology that can connect them. Inundated exceedance probability (IEP and its district concept are suggested to gain insights into hydrological regimes on the Binae wetland that is rehabilitated by the Restoration Project in 2012 and belong to the riparian zone. Results of this study indicate that the areas with P = 0.08 or lower IEPs should have the disturbance for vegetation communities, or could be changed to a hydrophilic vegetation in the study area, and it should be considered in the restoration and rehabilitation project to conserve legally protected or endangered vegetation.

Understanding global fire dynamics by classifying and comparing spatial models of vegetation and fire

Science.gov (United States)

Robert E. Keane; Geoffrey J. Cary; Ian D. Davies; Michael D. Flannigan; Robert H. Gardner; Sandra Lavorel; James M. Lenihan; Chao Li; T. Scott Rupp

2007-01-01

Wildland fire is a major disturbance in most ecosystems worldwide (Crutzen and Goldammer 1993). The interaction of fire with climate and vegetation over long time spans, often referred to as the fire regime (Agee 1993; Clark 1993; Swetnam and Baisan 1996; Swetnam 1997), has major effects on dominant vegetation, ecosystem carbon budget, and biodiversity (Gardner et aL...

Plant metabolites and nutritional quality of vegetables.

Science.gov (United States)

Hounsome, N; Hounsome, B; Tomos, D; Edwards-Jones, G

2008-05-01

Vegetables are an important part of the human diet and a major source of biologically active substances such as vitamins, dietary fiber, antioxidants, and cholesterol-lowering compounds. Despite a large amount of information on this topic, the nutritional quality of vegetables has not been defined. Historically, the value of many plant nutrients and health-promoting compounds was discovered by trial and error. By the turn of the century, the application of chromatography, mass spectrometry, infrared spectrometry, and nuclear magnetic resonance allowed quantitative and qualitative measurements of a large number of plant metabolites. Approximately 50000 metabolites have been elucidated in plants, and it is predicted that the final number will exceed 200000. Most of them have unknown function. Metabolites such as carbohydrates, organic and amino acids, vitamins, hormones, flavonoids, phenolics, and glucosinolates are essential for plant growth, development, stress adaptation, and defense. Besides the importance for the plant itself, such metabolites determine the nutritional quality of food, color, taste, smell, antioxidative, anticarcinogenic, antihypertension, anti-inflammatory, antimicrobial, immunostimulating, and cholesterol-lowering properties. This review is focused on major plant metabolites that characterize the nutritional quality of vegetables, and methods of their analysis.

Bonneville - Hood River Vegetation Management Environmental Assessment

Energy Technology Data Exchange (ETDEWEB)

N/A

1998-08-01

To maintain the reliability of its electrical system, BPA, in cooperation with the U.S. Forest Service, needs to expand the range of vegetation management options used to clear unwanted vegetation on about 20 miles of BPA transmission line right-of-way between Bonneville Dam and Hood River; Oregon, within the Columbia Gorge National Scenic Area (NSA). We propose to continue controlling undesirable vegetation using a program of Integrated Vegetation Management (IVM) which includes manual, biological and chemical treatment methods. BPA has prepared an Environmental Assessment (EA) (DOE/EA-1257) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and BPA is issuing this FONSI.

Overnight shift work: factors contributing to diagnostic discrepancies.

Science.gov (United States)

Hanna, Tarek N; Loehfelm, Thomas; Khosa, Faisal; Rohatgi, Saurabh; Johnson, Jamlik-Omari

2016-02-01

The aims of the study are to identify factors contributing to preliminary interpretive discrepancies on overnight radiology resident shifts and apply this data in the context of known literature to draw parallels to attending overnight shift work schedules. Residents in one university-based training program provided preliminary interpretations of 18,488 overnight (11 pm–8 am) studies at a level 1 trauma center between July 1, 2013 and December 31, 2014. As part of their normal workflow and feedback, attendings scored the reports as major discrepancy, minor discrepancy, agree, and agree--good job. We retrospectively obtained the preliminary interpretation scores for each study. Total relative value units (RVUs) per shift were calculated as an indicator of overnight workload. The dataset was supplemented with information on trainee level, number of consecutive nights on night float, hour, modality, and per-shift RVU. The data were analyzed with proportional logistic regression and Fisher's exact test. There were 233 major discrepancies (1.26 %). Trainee level (senior vs. junior residents; 1.08 vs. 1.38 %; p performance. Increased workload affected more junior residents' performance, with R3 residents performing significantly worse on busier nights. Hour of the night was not significantly associated with performance, but there was a trend toward best performance at 2 am, with subsequent decreased accuracy throughout the remaining shift hours. Improved performance occurred after the first six night float shifts, presumably as residents acclimated to a night schedule. As overnight shift work schedules increase in popularity for residents and attendings, focused attention to factors impacting interpretative accuracy is warranted.

Australian consumer awareness of health benefits associated with vegetable consumption.

Science.gov (United States)

Rekhy, Reetica; Khan, Aila; Eason, Jocelyn; Mactavish-West, Hazel; Lister, Carolyn; Mcconchie, Robyn

2017-04-01

The present study investigated the perceived health benefits of specific vegetable consumption to guide the use of nutrition and health claims on vegetable marketing collateral. Free elicitation and consumer ranking data were collected through an online survey of 1000 adults from across Australia and analysed for the perceived importance of vegetables in the daily diet, number of serves consumed per day, knowledge about health-related benefits of specific vegetables and perceived health benefits of vegetable consumption. The importance of vegetables in the diet and daily vegetable consumption was higher in people from an English-speaking background, females, people aged 45 years and over and people living in non-metropolitan areas. Digestion was selected as the major health benefit from consumption of specific vegetables. However, understanding of the health benefits of specific vegetable consumption was relatively low among consumers. Half of the respondents were not sure of the health benefits associated with specific vegetables, except for carrots and spinach. Some respondents volunteered nutrient content or other information. There was no clear indication that consumers understand the specific health benefits conferred by consumption of vegetables. Nutrient and health benefit labelling therefore has the capacity to enhance knowledge of vegetable consumers. It is recommended that health benefit labelling be tailored to promote greater consumption of vegetables in those demographic groups where vegetable consumption was lower. The present study assists the Australian vegetable industry in helping consumers make more informed consumption choices. © 2016 Dietitians Association of Australia.

Vegetable oil spills : oil properties and behaviour

International Nuclear Information System (INIS)

Fingas, M.; Fieldhouse, B.; Jokuty, P.

2001-01-01

In 1997, the United States Environmental Protection Agency conducted a thorough review of the issue regarding vegetable oil spills. Recent attention has refocused on this issue as a result of an incident where 20 tons of canola oil was spilled in the Vancouver Harbour in 2000. In the past, vegetable oils were suggested to be a useful test material because they were thought to be innocuous. It was even suggested they be used to remove petroleum oil residues from beaches. However, recent studies have shown that spills of vegetable oils can have major environmental consequences, equivalent to those of petroleum oil spills. The spills have devastating effects on birds and intertidal organisms. This paper presented a summary of historical vegetable spills from around the world. In this study, specific behaviour tests were examined for several oils including canola, soy bean, olive, castor and corn oils. Evaporation, water-in-oil emulsification and chemical dispersion were measured and were found to be nearly zero, suggesting that vegetable oil spills are not very soluble in water. The aquatic toxicity of vegetable oil is low, but their fate is quite different from petroleum. Vegetable oils do not evaporate to a significant degree, they do not form water-in-oil emulsions, nor do they disperse in water. The physical properties of vegetable oils were also measured, including density and viscosity. This paper presented the aquatic toxicity of several vegetable oils along with other environmental data including the degradation rates noted in the literature. Most environmental damage reported in the literature is by contact with birds feathers resulting in hypothermia and secondly by smothering of intertidal organisms. The effect of vegetable oil on fish has not been well studied, but it is expected that there will be little destructive effect except where smothering can occur. 35 refs., 3 tabs

Vegetable oil spills : oil properties and behaviour

Energy Technology Data Exchange (ETDEWEB)

Fingas, M.; Fieldhouse, B.; Jokuty, P. [Environment Canada, Ottawa, ON (Canada). Emergencies Science Div

2001-07-01

In 1997, the United States Environmental Protection Agency conducted a thorough review of the issue regarding vegetable oil spills. Recent attention has refocused on this issue as a result of an incident where 20 tons of canola oil was spilled in the Vancouver Harbour in 2000. In the past, vegetable oils were suggested to be a useful test material because they were thought to be innocuous. It was even suggested they be used to remove petroleum oil residues from beaches. However, recent studies have shown that spills of vegetable oils can have major environmental consequences, equivalent to those of petroleum oil spills. The spills have devastating effects on birds and intertidal organisms. This paper presented a summary of historical vegetable spills from around the world. In this study, specific behaviour tests were examined for several oils including canola, soy bean, olive, castor and corn oils. Evaporation, water-in-oil emulsification and chemical dispersion were measured and were found to be nearly zero, suggesting that vegetable oil spills are not very soluble in water. The aquatic toxicity of vegetable oil is low, but their fate is quite different from petroleum. Vegetable oils do not evaporate to a significant degree, they do not form water-in-oil emulsions, nor do they disperse in water. The physical properties of vegetable oils were also measured, including density and viscosity. This paper presented the aquatic toxicity of several vegetable oils along with other environmental data including the degradation rates noted in the literature. Most environmental damage reported in the literature is by contact with birds feathers resulting in hypothermia and secondly by smothering of intertidal organisms. The effect of vegetable oil on fish has not been well studied, but it is expected that there will be little destructive effect except where smothering can occur. 35 refs., 3 tabs.

A Modeling Approach for Evaluating the Coupled Riparian Vegetation-Geomorphic Response to Altered Flow Regimes

Science.gov (United States)

Manners, R.; Wilcox, A. C.; Merritt, D. M.

2016-12-01

The ecogeomorphic response of riparian ecosystems to a change in hydrologic properties is difficult to predict because of the interactions and feedbacks among plants, water, and sediment. Most riparian models of community dynamics assume a static channel, yet geomorphic processes strongly control the establishment and survival of riparian vegetation. Using a combination of approaches that includes empirical relationships and hydrodynamic models, we model the coupled vegetation-topographic response of three cross-sections on the Yampa and Green Rivers in Dinosaur National Monument, to a shift in the flow regime. The locations represent the variable geomorphology and vegetation composition of these canyon-bound rivers. We account for the inundation and hydraulic properties of vegetation plots surveyed over three years within International River Interface Cooperative (iRIC) Fastmech, equipped with a vegetation module that accounts for flexible stems and plant reconfiguration. The presence of functional groupings of plants, or those plants that respond similarly to environmental factors such as water availability and disturbance are determined from flow response curves developed for the Yampa River. Using field measurements of vegetation morphology, distance from the channel centerline, and dominant particle size and modeled inundation properties we develop an empirical relationship between these variables and topographic change. We evaluate vegetation and channel form changes over decadal timescales, allowing for the integration of processes over time. From our analyses, we identify thresholds in the flow regime that alter the distribution of plants and reduce geomorphic complexity, predominately through side-channel and backwater infilling. Simplification of some processes (e.g., empirically-derived sedimentation) and detailed treatment of others (e.g., plant-flow interactions) allows us to model the coupled dynamics of riparian ecosystems and evaluate the impact of

Study on the air quality near vegetation along the highway

International Nuclear Information System (INIS)

Weijers, E.P.; Kos, G.P.A.; Van den Bulk, W.C.M.; Vermeulen, A.T.

2007-08-01

The results of downwind measurements of air quality around vegetation near a motorway are presented and discussed. The study (first ever in the Netherlands) was performed by order of the Innovation Programme Air Quality. At a carefully selected location measurements of PM and NOx were carried out downwind from a motorway in front of and (at various distances) behind a parallel orientated vegetation strip. Results are compared with synchronized data collected at a nearby location without vegetation (the 'reference' situation) and at the same distances from the motorway. Major findings are: Comparing measurements in front of and behind the vegetation strip show that the presence of vegetation tends to lower PM10 and PM2.5 concentrations immediately behind the vegetation. However, no such change is apparent in the concentrations of NO and NO2. The comparison with measurements executed without vegetation ('reference') indicate that concentration levels close to the vegetation strip are similar or somewhat higher. At a larger distance from motorway and vegetation (>30 m) NO and NO2 concentrations tend to be lower than what is observed in the reference situation. This could not be determined for PM [nl

Mapping and characterizing the vegetation types of the Democratic Republic of Congo using SPOT VEGETATION time series

Science.gov (United States)

Vancutsem, C.; Pekel, J.-F.; Evrard, C.; Malaisse, F.; Defourny, P.

2009-02-01

The need for quantitative and accurate information to characterize the state and evolution of vegetation types at a national scale is widely recognized. This type of information is crucial for the Democratic Republic of Congo, which contains the majority of the tropical forest cover of Central Africa and a large diversity of habitats. In spite of recent progress in earth observation capabilities, vegetation mapping and seasonality analysis in equatorial areas still represent an outstanding challenge owing to high cloud coverage and the extent and limited accessibility of the territory. On one hand, the use of coarse-resolution optical data is constrained by performance in the presence of cloud screening and by noise arising from the compositing process, which limits the spatial consistency of the composite and the temporal resolution. On the other hand, the use of high-resolution data suffers from heterogeneity of acquisition dates, images and interpretation from one scene to another. The objective of the present study was to propose and demonstrate a semi-automatic processing method for vegetation mapping and seasonality characterization based on temporal and spectral information from SPOT VEGETATION time series. A land cover map with 18 vegetation classes was produced using the proposed method that was fed by ecological knowledge gathered from botanists and reference documents. The floristic composition and physiognomy of each vegetation type are described using the Land Cover Classification System developed by the FAO. Moreover, the seasonality of each class is characterized on a monthly basis and the variation in different vegetation indicators is discussed from a phenological point of view. This mapping exercise delivers the first area estimates of seven different forest types, five different savannas characterized by specific seasonality behavior and two aquatic vegetation types. Finally, the result is compared to two recent land cover maps derived from

A reconnaissance survey of the vegetation of the North Luangwa National Park, Zambia

Directory of Open Access Journals (Sweden)

P. P. Smith

1998-10-01

Full Text Available A comprehensive survey of the vegetation of the North Luangwa National Park (NLNP was carried out over a period of two years. The main aims of the survey were to describe the major vegetation communities in the park and to produce a vegetation map of the NLNP Initial differentiation of vegetation units was established by the appearance of the vegetation on aerial photographs Further information was derived from 353 ground plots in which > 20 000 woody plants were identified and measured Thirteen broad vegetation types were recognised in the NLNP Details of their physiognomy, species composition, distribution, topography and edaphic associations are given.

Small-scale shifting mosaics of two dominant grassland species: the possible role of soil-borne pathogens

NARCIS (Netherlands)

Olff, H.; Hoorens, B.; De Goede, R.G.M.; Van der Putten, W.H.; Gleichman, J.M.

2000-01-01

We analyzed the dynamics of dominant plant species in a grazed grassland over 17 years, and investigated whether local shifts in these dominant species, leading to vegetation mosaics, could be attributed to interactions between plants and soil-borne pathogens. We found that Festuca rubra and Carer

Small-scale shifting mosaics of two dominant grassland species : the possible role of soil-borne pathogens

NARCIS (Netherlands)

Olff, H.; Hoorens, B.; Goede, R.G.M. de; Putten, W.H. van der; Gleichman, J.M.

2000-01-01

We analyzed the dynamics of dominant plant species in a grazed grassland over 17 years, and investigated whether local shifts in these dominant species, leading to vegetation mosaics, could be attributed to interactions between plants and soil-borne pathogens. We found that Festuca rubra and Carex

Vegetation impoverishment despite greening: a case study from central Senegal

Science.gov (United States)

Herrmann, Stefanie M.; Tappan, G. Gray

2013-01-01

Recent remote sensing studies have documented a greening trend in the semi-arid Sahel and Sudan zones of West Africa since the early 1980s, which challenges the mainstream paradigm of irreversible land degradation in this region. What the greening trend means on the ground, however, has not yet been explored. This research focuses on a region in central Senegal to examine changes in woody vegetation abundance and composition in selected sites by means of a botanical inventory of woody vegetation species, repeat photography, and perceptions of local land users. Despite the greening, an impoverishment of the woody vegetation cover was observed in the studied sites, indicated by an overall reduction in woody species richness, a loss of large trees, an increasing dominance of shrubs, and a shift towards more arid-tolerant, Sahelian species since 1983. Thus, interpretation of the satellite-derived greening trend as an improvement or recovery is not always justified. The case of central Senegal represents only one of several possible pathways of greening throughout the region, all of which result in similar satellite-derived greening signals.

Holocene vegetation and climate change on the Haanja heights, South-East Estonia

International Nuclear Information System (INIS)

Saarse, Leili; Rajamaee, Raivo

1997-01-01

The development of forests on the Haanja Heights has been controlled by external factors, including climate, soils, hydrology, and human impact. The sediment sequence from Lake Kirikumaee, which covers about 12 000 years, records the vegetation history throughout the Late Glacial and Holocene. In the Alleroed, woodland tundra with sparse birch and willow was established. Grass-shrub tundra in the Younger Dryas was replaced by birch forest in the Pre-Boreal. During the Holocene two major shifts in vegetation dynamics occurred: the first about 8500 BP with a sharp decline in Betula-Pinus forest and development of broad-leaved forest, and the second about 3500 BP, with a decline in broad-leaved forest and regeneration of Pinus-Betula forest with a high share of Picea. The climate modelling, based on pollen record and lake-level changes, suggest cold, severe climate with low precipitation values in the early Pre-Boreal. Between 9500-8500 BP the climate was rather stable. The lake level first rose, then stabilized, and finally dropped. The sharp climate amelioration in the late Boreal together with the humidity increase resulted in a lake-level rise. The decreased precipitation and rather high summer temperatures, increased evapotranspiration, and reduced water balance are characteristic of the Sub-Boreal. Since 3500 BP, the climate deteriorated and mixed coniferous forest started to dominate. Several small climatic fluctuations, including the Little Ice Age cooling, have been traced by modelling. (author)

Water quality function of an extensive vegetated roof.

Science.gov (United States)

Todorov, Dimitar; Driscoll, Charles T; Todorova, Svetoslava; Montesdeoca, Mario

2018-06-01

In this paper we present the results of a four-year study of water quality in runoff from an extensive, sedum covered, vegetated roof on an urban commercial building. Monitoring commenced seven months after the roof was constructed, with the first growing season. Stormwater drainage quality function of the vegetated roof was compared to a conventional (impermeable, high-albedo) membrane roof in addition to paired measurements of wet and bulk depositions at the study site. We present concentrations and fluxes of nutrients and major solutes. We discuss seasonal and year-to-year variation in water quality of drainage from the vegetated roof and how it compares with atmospheric deposition and drainage from the impermeable roof. Drainage waters from the vegetated roof exhibited a high concentration of nutrients compared to atmospheric deposition, particularly during the warm temperature growing season. However, nutrient losses were generally low because of the strong retention of water by the vegetated roof. There was marked variation in the retention of nutrients by season due to variations in concentrations in drainage from the vegetated roof. The vegetated roof was a sink of nitrogen, total phosphorus and chloride, and a source of phosphate and dissolved inorganic and organic carbon. Chloride exhibited elevated inputs and leaching during the winter. The drainage from the vegetated and impermeable roofs met the United States Environmental Protection Agency freshwater standards for all parameters, except for total phosphorus. Copyright © 2017 Elsevier B.V. All rights reserved.

Vegetation coupling to global climate: Trajectories of vegetation change and phenology modeling from satellite observations

Science.gov (United States)

Fisher, Jeremy Isaac

Important systematic shifts in ecosystem function are often masked by natural variability. The rich legacy of over two decades of continuous satellite observations provides an important database for distinguishing climatological and anthropogenic ecosystem changes. Examples from semi-arid Sudanian West Africa and New England (USA) illustrate the response of vegetation to climate and land-use. In Burkina Faso, West Africa, pastoral and agricultural practices compete for land area, while degradation may follow intensification. The Nouhao Valley is a natural experiment in which pastoral and agricultural land uses were allocated separate, coherent reserves. Trajectories of annual net primary productivity were derived from 18 years of coarse-grain (AVHRR) satellite data. Trends suggested that pastoral lands had responded rigorously to increasing rainfall after the 1980's droughts. A detailed analysis at Landsat resolution (30m) indicated that the increased vegetative cover was concentrated in the river basins of the pastoral region, implying a riparian wood expansion. In comparison, riparian cover was reduced in agricultural regions. We suggest that broad-scale patterns of increasing semi-arid West African greenness may be indicative of climate variability, whereas local losses may be anthropogenic in nature. The contiguous deciduous forests, ocean proximity, topography, and dense urban developments of New England provide an ideal landscape to examine influences of climate variability and the impact of urban development vegetation response. Spatial and temporal patterns of interannual climate variability were examined via green leaf phenology. Phenology, or seasonal growth and senescence, is driven by deficits of light, temperature, and water. In temperate environments, phenology variability is driven by interannual temperature and precipitation shifts. Average and interannual phenology analyses across southern New England were conducted at resolutions of 30m (Landsat

Satellite time-series data for vegetation phenology detection and environmental assessment in Southeast Asia

Science.gov (United States)

Suepa, Tanita

and internal climatic fluctuation. The EVI and phenological patterns varied spatially according to climate variations and human management. The overall regional mean EVI value in SEA from 2001 to 2010 has gradually decreased and phenological trends appeared to shift towards a later and slightly longer growing season. Regional vegetation dynamics over SEA exhibited patterns associated with major climate events such as El Nino in 2005. The rainy season tended to start early and end late and the length of rainy season was slightly longer. However, the amount of rainfall has decreased from 2001 to 2010. The relationship between phenology and rainfall varied among different ecosystems. Additionally, the local scale results indicated that rainfall is a dominant force of phenological changes in naturally vegetated areas and rainfed croplands, whereas human management is a key factor in heavily agricultural areas with irrigated systems. The results of estimating GHG emissions from rice fields in Thailand demonstrated that human management, climate variation, and physical geography had a significant influence on the change in GHG emissions. In addition, the complexity of spatio-temporal patterns in phenology and related variables were displayed on the visualization system with effective functions and an interactive interface. The information and knowledge in this research are useful for local and regional environmental management and for identifying mitigation strategies in the context of climate change and ecosystem dynamics in this region.

The Role of Riparian Vegetation in Protecting and Improving Chemical Water Quality in Streams

Science.gov (United States)

Michael G. Dosskey; Philippe Vidon; Noel P. Gurwick; Craig J. Allan; Tim P. Duval; Richard Lowrance

2010-01-01

We review the research literature and summarize the major processes by which riparian vegetation influences chemical water quality in streams, as well as how these processes vary among vegetation types, and discuss how these processes respond to removal and restoration of riparian vegetation and thereby determine the timing and level of response in stream water quality...

Work-to-family spillover and fruit and vegetable consumption among construction laborers.

Science.gov (United States)

Devine, Carol M; Stoddard, Anne M; Barbeau, Elizabeth M; Naishadham, Deepa; Sorensen, Glorian

2007-01-01

Spillover is the effect of one role on another as working adults attempt to integrate demands from work and family. We conducted a survey to understand how worker, job, and family characteristics were related to negative work-to-family spillover and how spillover was related to fruit and vegetable consumption to inform intervention design. A combined mail and telephone survey. A national random sample in the United States. 1108 (44% response) unionized construction laborers. Personal characteristics, job factors, family factors, work-to-family spillover, and fruit and vegetable consumption. Multivariable logistic and least-squares regression. A range of 20% to 50% of respondents reported negative work-to-family spillover, agreeing that work demands, time, fatigue, and stress interfered with family meals or food choices. Higher spillover was associated with job factors, being of white race/ethnicity, and having children at home. Lower fruit and vegetable consumption was associated with higher work-to-family spillover (p = .002), being of white race or ethnicity (p working the graveyard or day shift (p = .02). Negative experience of work-to-family spillover may link employment to fruit and vegetable consumption and thus to worker health. Understanding the contribution of spillover to fruit and vegetable consumption aids understanding of how work experience affects health.

Simulating the Dependence of Sagebrush Steppe Vegetation on Redistributed Snow in a Semi-Arid Watershed.

Science.gov (United States)

Soderquist, B.; Kavanagh, K.; Link, T. E.; Strand, E. K.; Seyfried, M. S.

2014-12-01

In mountainous regions across the western USA, the composition of aspen (Populus tremuloides) and sagebrush steppe plant communities is often closely related to heterogeneous soil moisture subsidies resulting from redistributed snow. With decades of climate and precipitation data across elevational and precipitation gradients, the Reynolds Creek Experimental Watershed (RCEW) and critical zone observatory (CZO) in southwest Idaho provides a unique opportunity to study the relationship between vegetation types and redistributed snow. Within the RCEW, the total amount of precipitation has remained unchanged over the past 50 years, however the percentage of the precipitation falling as snow has declined by approximately 4% per decade at mid-elevation sites. As shifts in precipitation phase continue, future trends in vegetation composition and net primary productivity (NPP) of different plant functional types remains a critical question. We hypothesize that redistribution of snow may supplement drought sensitive species like aspen more so than drought tolerant species like mountain big sagebrush (Artemisia tridentata spp. vaseyana). To assess the importance of snowdrift subsidies on sagebrush steppe vegetation, NPP of aspen, shrub, and grass species was simulated at three sites using the biogeochemical process model BIOME-BGC. Each site is located directly downslope from snowdrifts providing soil moisture inputs to aspen stands and neighboring vegetation. Drifts vary in size with the largest containing up to four times the snow water equivalent (SWE) of a uniform precipitation layer. Precipitation inputs used by BIOME-BGC were modified to represent the redistribution of snow and simulations were run using daily climate data from 1985-2013. Simulated NPP of annual grasses at each site was not responsive to subsidies from drifting snow. However, at the driest site, aspen and shrub annual NPP was increased by as much as 44 and 30%, respectively, with the redistribution of

Ontogenetic specialism in predators with multiple niche shifts prevents predator population recovery and establishment

NARCIS (Netherlands)

van Leeuwen, A.; Huss, M.; Gårdmark, A.; de Roos, A.M.

2014-01-01

The effects of ontogenetic niche shifts on community structure and dynamics are underexplored, despite the occurrence of such shifts in the majority of animal species. We studied the form of niche shifts in a predator that exhibits multiple ontogenetic niche shifts, and analyzed how this life

Medium Scale Central Valley Riparian Vegetation and Land Use with Aggregated Delta Veg, 2011 [ds724

Data.gov (United States)

California Natural Resource Agency — Geodatabase (SDE) feature class containing map of vegetation along mainstem rivers and major tributaries (including ancillary natural and semi-natural vegetation)...

Leadership Shifts in Changing Field

Science.gov (United States)

Zubrzycki, Jaclyn

2013-01-01

As groups representing local and state education players struggle to remain relevant in a policy conversation often dominated by foundations, think tanks, new advocacy groups, and political and business figures, a shift in leadership has been under way at major associations. Most of the changes have come as part of the natural churn; former…

Spray drying of fruit and vegetable juices--a review.

Science.gov (United States)

Verma, Anjali; Singh, Satya Vir

2015-01-01

The main cause of spray drying is to increase the shelf life and easy handling of juices. In the present paper, the studies carried out so far on spray drying of various fruits and vegetables are reported. The major fruit juices dried are mango, banana, orange, guava, bayberry, watermelon, pineapple, etc. However, study on vegetable juices is limited. In spray drying, the major optimized parameters are inlet air temperature, relative humidity of air, outlet air temperature, and atomizer speed that are given for a particular study. The juices in spray drying require addition of drying agents that include matlodextrin, liquid glucose, etc. The drying agents are added to increase the glass transition temperature. Different approaches for spray dryer design have also been discussed in the present work.

Orbital scale vegetation change in Africa

Science.gov (United States)

Dupont, Lydie

2011-12-01

Palynological records of Middle and Late Pleistocene marine sediments off African shores is reviewed in order to reveal long-term patterns of vegetation change during climate cycles. Whether the transport of pollen and spores from the source areas on the continent to the ocean floor is mainly by wind or predominantly by rivers depends on the region. Despite the differences in transportation, accumulation rates in the marine sediments decline exponentially with distance to the shore. The marine sediments provide well-dated records presenting the vegetation history of the main biomes of western and southern Africa. The extent of different biomes varied with the climate changes of the glacial interglacial cycle. The Mediterranean forest area expanded during interglacials, the northern Saharan desert during glacials, and the semi-desert area in between during the transitions. In the sub-Saharan mountains ericaceous scrubland spread mainly during glacials and the mountainous forest area often increased during intermediate periods. Savannahs extended or shifted to lower latitudes during glacials. While the representation of the tropical rain forest fluctuated with summer insolation and precession, that of the subtropical biomes showed more obliquity variability or followed the pattern of glacial and interglacials.

Suppression of vegetation in LANDSAT ETM+ remote sensing images

Science.gov (United States)

Yu, Le; Porwal, Alok; Holden, Eun-Jung; Dentith, Michael

2010-05-01

value and scaling all pixels at each vegetation index level by an amount that shifts the curve to the target digital number (DN). The main drawback of their algorithm is severe distortions of the DN values of non-vegetated areas, a suggested solution is masking outliers such as cloud, water, etc. We therefore extend this algorithm by masking non-vegetated areas. Our algorithm comprises the following three steps: (1) masking of barren or sparsely vegetated areas using a threshold based on a vegetation index that is calculated after atmosphere correction (dark pixel correction and ACTOR were compared) in order to conserve their original spectral information through the subsequent processing; (2) applying Crippen and Blom's forced invariance algorithm to suppress the spectral response of vegetation only in vegetated areas; and (3) combining the processed vegetated areas with the masked barren or sparsely vegetated areas followed by histogram equalization to eliminate the differences in color-scales between these two types of areas, and enhance the integrated image. The output images of both study areas showed significant improvement over the original images in terms of suppression of vegetation reflectance and enhancement of the underlying geological information. The processed images show clear banding, probably associated with lithological variations in the underlying rock formations. The colors of non-vegetated pixels are distorted in the unmasked results but in the same location the pixels in the masked results show regions of higher contrast. We conclude that the algorithm offers an effective way to enhance geological information in LANDSAT TM/ETM+ images of terrains with significant vegetation cover. It is also suitable to other multispectral satellite data have bands in similar wavelength regions. In addition, an application of this method to hyperspectral data may be possible as long as it can provide the vegetation band ratios.

Towards a theory of ecotone resilience: coastal vegetation on a salinity gradient.

Science.gov (United States)

Jiang, Jiang; Gao, Daozhou; DeAngelis, Donald L

2012-08-01

Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a 'press', for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances. Published by Elsevier Inc.

Urban vegetation and thermal patterns following city growth in different socio-economic contexts

Science.gov (United States)

Dronova, I.; Clinton, N.; Yang, J.; Radke, J.; Marx, S. S.; Gong, P.

2015-12-01

Urban expansion accompanied by losses of vegetated spaces and their ecological services raises significant concerns about the future of humans in metropolitan "habitats". Despite recent growth of urban studies globally, it is still not well understood how environmental effects of urbanization vary with the rate and socioeconomic context of development. Our study hypothesized that with urban development, spatial patterns of surface thermal properties and green plant cover would shift towards higher occurrence of relatively warmer and less vegetated spaces such as built-up areas, followed by losses of greener and cooler areas such as urban forests, and that these shifts would be more pronounced with higher rate of economic and/or population growth. To test these ideas, we compared 1992-2011 changes in remotely sensed patterns of green vegetation and surface temperature in three example cities that experienced peripheral growth under contrasting socio-economic context - Dallas, TX, USA, Beijing, China and Kyiv, Ukraine. To assess their transformation, we proposed a metric of thermal-vegetation angle (TVA) estimated from per-pixel proxies of vegetation greenness and surface temperature from Landsat satellite data and examined changes in TVA distributions within each city's core and two decadal zones of peripheral sprawl delineated from nighttime satellite data. We found that higher economic and population growth were coupled with more pronounced changes in TVA distributions, and more urbanized zones often exhibited higher frequencies of warmer, less green than average TVA values with novel patterns such as "cooler" clusters of building shadows. Although greener and cooler spaces generally diminished with development, they remained relatively prevalent in low-density residential areas of Dallas and peripheral zones of Kyiv with exurban subsistence farming. Overall, results indicate that the effects of modified green space and thermal patterns within growing cities

A west-east vegetation transect through Africa south of the Tropic of Capricorn

Directory of Open Access Journals (Sweden)

B. J. Coetzee

1975-11-01

Full Text Available Changes in predominant vegetation physiognomy, prominent species and physiography along the route following an I 800 km transect across southern Africa near the Tropic of Capricorn, are described. Eleven main discontinuities in the structure and Holistic composition of the vegetation along the transect are related to a climatic gradient across the Continent. Floristic variation within the main structural types is largely related to rainfall, severity of frost, soil conditions, exposure, slope and aspect. The main vegetation classes distinguished coincide largely with major differences in carrying capacity of the vegetation.

A Need For Paradigm Shift to Improve Supply Chain Management of Fruits & Vegetables in India

OpenAIRE

Piali Halder; Simayan Pati

2011-01-01

As the Indian population is increasing, the demand for fresh fruits and vegetables is also increasing. Owing to the perishable nature and very short shelf life, these items require proper storage and transportation facilities in order to reach to the customer in fresh state. A lack of investment in agriculture makes the country vulnerable to international price shocks as well as exchange-rate volatility. This requires a considerable amount of effort from the involved parties. The entire chain...

Night Shift Work and Its Health Effects on Nurses.

Science.gov (United States)

Books, Candie; Coody, Leon C; Kauffman, Ryan; Abraham, Sam

The purpose of this research was to study night shift work and its health effects on nurses. This was a quantitative study using descriptive design; it also incorporated three qualitative open-ended questions to complement the study. The data were collected using Survey Monkey, with an Internet-based confidential data collection tool. The population of relevance to this study was nurses employed in hospital settings in the United States. E-mail addresses and Facebook were used to recruit participants. Results indicated that there is an increased risk of sleep deprivation, family stressors, and mood changes because of working the night shift. Rotating shifts were mentioned as a major concern for night shift nurses. Respondents agreed that complaints about fatigue and fatigue-related illnesses in night shift workers were ignored. There was also a general perception among nurses working the night shift that sleep deprivation leads to negative health consequences including obesity; however, they were not as high a concern as rotating shifts or fatigue.

The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change

Directory of Open Access Journals (Sweden)

B. Reu

2011-05-01

Full Text Available The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current vegetation models employ empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider trade-offs in plant functioning and their responses under climatic changes to forecast and explain changes in plant functional richness and shifts in biome geographic distributions.

The Jena Diversity model (JeDi simulates plant survival according to essential plant functional trade-offs, including ecophysiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We use JeDi to quantify changes in plant functional richness and biome shifts between present-day and a range of possible future climates from two SRES emission scenarios (A2 and B1 and seven global climate models using metrics of plant functional richness and functional identity.

Our results show (i a significant loss of plant functional richness in the tropics, (ii an increase in plant functional richness at mid and high latitudes, and (iii a pole-ward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships. Such a mechanistic approach may be particularly relevant when addressing vegetation responses to climatic changes that encounter novel combinations of climate parameters that do not exist under contemporary climate.

Rendering Future Vegetation Change across Large Regions of the US

Science.gov (United States)

Sant'Anna Dias, Felipe; Gu, Yuting; Agarwalla, Yashika; Cheng, Yiwei; Patil, Sopan; Stieglitz, Marc; Turk, Greg

2015-04-01

the period 2061 - 2080. The predicted mean annual air temperature change for the three sites ranged from + 1.8°C to + 2.3°C. Precipitation for the three sites changed little. In Oregon, this resulted in a 37% shift of forested areas to shrub vegetation. In New Mexico, shrubs and evergreen vegetation increased by 18% and 5%, respectively. Deciduous and grassland vegetation decreased by 90% and 52%, respectively. In Washington, evergreen vegetation cover decreased by 4.5%. Deciduous vegetation increase by 25%. Shrubs and grasslands increased by 15% and 7%, respectively. Perennial snow cover on mountain tops fell by 46%. Beyond rendering a view of future vegetation cover, we also extracted information regarding the relative controls that climate and topography exert over local vegetation. The three most dominant controls are elevation (most dominant), temperature, and precipitation. In summary, we demonstrate a framework for rendering potential future vegetation in a visually realistic way. Moreover, these machine learning techniques provide a computationally fast framework for exploring the effects of climate change over large-areas and at high-spatial resolution that cannot be accomplished through simulation alone.

Dose construction for vegetable ingestion exposure in Hong Kong

International Nuclear Information System (INIS)

Lui, W.S.; Walton, A.; Yeung, M.R.

1997-01-01

The author presents the mathematical model TERRA used for the construction of ingestion doses resulting from the consumption of contaminated vegetables during a nuclear accident in Hong Kong. Using the ground surface deposited radionuclide densities as input, TERRA calculates the concentrations of 54 radionuclides on the surfaces and within the tissue of vegetables as a function of time and the radiation doses delivered to the various vital organs following their consumption by humans. The present model provides a convenient tool to determine the time histories of 54 radionuclides in vegetables and to back track or project the ingestion dose after a major accident such that more appropriate and timely countermeasures can be implemented

Review of vegetable fermentations with particular emphasis on processing modifications, microbial ecology, and spoilage

Science.gov (United States)

The consumption of vegetables is widespread in the world and represents a major component of the human diet. Microorganisms (mainly lactic acid bacteria, yeasts, Enterobacteriaceae, Propionibacterium and Clostridium species) play a significant role in vegetable fermentations, affecting the quality a...

Exploring Demographic Shifts : Aging and Migration Exploratory Group Model Specification & Simulation

NARCIS (Netherlands)

Pruyt, E.; Logtens, T.; Gijsbers, G.

2011-01-01

Plausible dynamics of a major demographic shift –(societal) aging– is studied in this paper, both from a global perspective and from a national perspective. Several economic, political and social implications of aging and aging-related demographic shifts are explored using System Dynamics models as

Modelling post-fire vegetation recovery in Portugal

Science.gov (United States)

Bastos, A.; Gouveia, C. M.; Dacamara, C. C.; Trigo, R. M.

2011-12-01

Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion. The main goals of the present work are (i) to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii) to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii) to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively. The study relies on monthly values of NDVI over 11 years (1998-2009), at 1 km × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus pinaster over the area, and by the fact that coniferous forests tend to recover slower than transitional woodland

The Prediction of Drought-Related Tree Mortality in Vegetation Models

Science.gov (United States)

Schwinning, S.; Jensen, J.; Lomas, M. R.; Schwartz, B.; Woodward, F. I.

2013-12-01

Drought-related tree die-off events at regional scales have been reported from all wooded continents and it has been suggested that their frequency may be increasing. The prediction of these drought-related die-off events from regional to global scales has been recognized as a critical need for the conservation of forest resources and improving the prediction of climate-vegetation interactions. However, there is no conceptual consensus on how to best approach the quantitative prediction of tree mortality. Current models use a variety of mechanisms to represent demographic events. Mortality is modeled to represent a number of different processes, including death by fire, wind throw, extreme temperatures, and self-thinning, and each vegetation model differs in the emphasis they place on specific mechanisms. Dynamic global vegetation models generally operate on the assumption of incremental vegetation shift due to changes in the carbon economy of plant functional types and proportional effects on recruitment, growth, competition and mortality, but this may not capture sudden and sweeping tree death caused by extreme weather conditions. We tested several different approaches to predicting tree mortality within the framework of the Sheffield Dynamic Global Vegetation Model. We applied the model to the state of Texas, USA, which in 2011 experienced extreme drought conditions, causing the death of an estimated 300 million trees statewide. We then compared predicted to actual mortality to determine which algorithms most accurately predicted geographical variation in tree mortality. We discuss implications regarding the ongoing debate on the causes of tree death.

Regime shifts and resilience in China's coastal ecosystems.

Science.gov (United States)

Zhang, Ke

2016-02-01

Regime shift often results in large, abrupt, and persistent changes in the provision of ecosystem services and can therefore have significant impacts on human wellbeing. Understanding regime shifts has profound implications for ecosystem recovery and management. China's coastal ecosystems have experienced substantial deterioration within the past decades, at a scale and speed the world has never seen before. Yet, information about this coastal ecosystem change from a dynamics perspective is quite limited. In this review, I synthesize existing information on coastal ecosystem regime shifts in China and discuss their interactions and cascading effects. The accumulation of regime shifts in China's coastal ecosystems suggests that the desired system resilience has been profoundly eroded, increasing the potential of abrupt shifts to undesirable states at a larger scale, especially given multiple escalating pressures. Policy and management strategies need to incorporate resilience approaches in order to cope with future challenges and avoid major losses in China's coastal ecosystem services.

Nitrogen Isotope Evidence for a Shift in Eastern Beringian Nitrogen Cycle after the Terminal Pleistocene

Science.gov (United States)

Tahmasebi, F.; Longstaffe, F. J.; Zazula, G.

2016-12-01

The loess deposits of eastern Beringia, a region in North America between 60° and 70°N latitude and bounded by Chukchi Sea to the west and the Mackenzie River to the east, are a magnificent repository of Late Pleistocene megafauna fossils. The stable carbon and nitrogen isotope compositions of these fossils are measured to determine the paleodiet of these animals, and hence the paleoenvironment of this ecosystem during the Quaternary. For this approach to be most successful, however, requires consideration of possible changes in nutrient cycling and hence the carbon and nitrogen isotopic compositions of vegetation in this ecosystem. To test for such a shift following the terminal Pleistocene, we analyzed the stable carbon and nitrogen isotope compositions of modern plants and bone collagen of Arctic ground squirrels from Yukon Territory, and fossil plants and bones recovered from Late Pleistocene fossil Arctic ground squirrel nests. The data for modern samples provided a measure of the isotopic fractionation between ground squirrel bone collagen and their diet. The over-wintering isotopic effect of decay on typical forage grasses was also measured to evaluate its role in determining fossil plant isotopic compositions. The grasses showed only a minor change ( 0-1 ‰) in carbon isotope composition, but a major change ( 2-10 ‰) in nitrogen isotope composition over the 317-day experiment. Based on the modern carbon isotope fractionation between ground squirrel bone collagen and their diet, the modern vegetation carbon isotopic baseline provides a suitable proxy for the Late Pleistocene of eastern Beringia, after accounting for the Suess effect. However, the predicted nitrogen isotope composition of vegetation comprising the diet of fossil ground squirrels remains 2.5 ‰ higher than modern grasslands in this area, even after accounting for possible N-15 enrichment during decay. This result suggests a change in N cycling in this region since the Late Pleistocene.

Into the millennium: farewell to majors

International Nuclear Information System (INIS)

Polczer, S.

1999-01-01

Conventional oil discoveries in Alberta peaked in the mid-1960s, marking a shift in the exploration strategies of the oil company majors that established Canada as a player in the world petroleum scene. Increasingly, they are shifting capital out of the country or look to unconventional sources for their new finds. Since they cannot find reserves needed to replace production, major oil companies have began to wind down their exploration programs, or shift to gas or oil sands, or exit altogether. According to the best expert opinion, future traditional exploration and production in Canada will be dominated by technically focused, entrepreneurial niche players using the latest technology to exploit lower quality reservoirs. The same expert source believes that Canada's contribution to the world's petroleum industry after 2000 will be primarily technological development, such as better drilling and well completion techniques. Past evidence suggest that Canada, while not a big player on the world petroleum scene, can and will continue to provide useful contribution to the industry by developing and exporting useful technology

Nutrient Density and the Cost of Vegetables from Elementary School Lunches.

Science.gov (United States)

Ishdorj, Ariun; Capps, Oral; Murano, Peter S

2016-01-01

Vegetables are the major source of the dietary fiber, magnesium, potassium, and vitamins A and C that are crucial in the diets of children. This study assessed the nutrient content of vegetables offered through the National School Lunch Program and examined the relation between the overall nutrient density of vegetable subgroups and the costs of nutrients offered and wasted before and after the changes in school meal standards. Using data collected from 3 elementary schools before and after the changes in school meal standards, we found that vegetable plate waste increased from 52% to 58%. Plate waste for starchy vegetables, exclusive of potatoes, was relatively high compared with other subgroups; however, plate waste for white potatoes was the lowest among any type of vegetable. Energy density; cost per 100 g, per serving, and per 100 kcal; and percentage daily value were calculated and used to estimate nutrient density value and nutrient density per dollar. Cost per 100 kcal was highest for red/orange vegetables followed by dark green vegetables; however, nutrient density for red/orange vegetables was the highest in the group and provided the most nutrients per dollar compared with other subgroups. Given that many vegetables are less energy dense, measuring vegetable costs per 100 g and per serving by accounting for nutrient density perhaps is a better way of calculating the cost of vegetables in school meals. © 2016 American Society for Nutrition.

Remote sensing captures varying temporal patterns of vegetation between human-altered and natural landscapes.

Science.gov (United States)

Leong, Misha; Roderick, George K

2015-01-01

Global change has led to shifts in phenology, potentially disrupting species interactions such as plant-pollinator relationships. Advances in remote sensing techniques allow one to detect vegetation phenological diversity between different land use types, but it is not clear how this translates to other communities in the ecosystem. Here, we investigated the phenological diversity of the vegetation across a human-altered landscape including urban, agricultural, and natural land use types. We found that the patterns of change in the vegetation indices (EVI and NDVI) of human-altered landscapes are out of synchronization with the phenology in neighboring natural California grassland habitat. Comparing these findings to a spatio-temporal pollinator distribution dataset, EVI and NDVI were significant predictors of total bee abundance, a relationship that improved with time lags. This evidence supports the importance of differences in temporal dynamics between land use types. These findings also highlight the potential to utilize remote sensing data to make predictions for components of biodiversity that have tight vegetation associations, such as pollinators.

VEGETATION MAPPING IN WETLANDS

Directory of Open Access Journals (Sweden)

F. PEDROTTI

2004-01-01

Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

Adaptation of Shift Sequence Based Method for High Number in Shifts Rostering Problem for Health Care Workers

Directory of Open Access Journals (Sweden)

Mindaugas Liogys

2013-08-01

is inefficient, because of large amount of shifts sequences (feasible shifts sequences are approximately 260 thousands.In order to speed up roster construction process shifts are grouped to four groups: morning shifts, day shifts, night shifts and duty shifts. There are only 64 feasible shifts sequences, in this case.After roster construction shift groups are replaced with the one of shift belonging to that group of shifts.When all shifts are added to roster, computation of workload for each schedule is performed. If computed workload is equal to the one defined in working contract, then this schedule is complete, else begin shifts revision process. During revision process those schedules are considered which do not meet work contract requirements.If computed workload is larger than the one defined in working contract, each shift is replaced with the shift, if it’s possible, with lesser duration time. If computed workload is lesser than the one defined in working contract, each shift is replaced with the shift, if it’s possible, with larger duration time.This process continues while schedule does not meet workload requirement defined in working contract or no further improvement can be made.Research limitations/implications—Problem dimension: 27 health care workers, 15 shifts, over 20 soft constraints, rostering period—one calendar month.Practical implications – modifications made to shift sequence based approach allows to construct a roster for one of the major Lithuania’s hospitals personnel in shorter time.Originality/Value—modification of shift sequence based approach is proposed.Research type: research paper.

Adaptation of Shift Sequence Based Method for High Number in Shifts Rostering Problem for Health Care Workers

Directory of Open Access Journals (Sweden)

Mindaugas Liogys

2011-08-01

problem is inefficient, because of large amount of shifts sequences (feasible shifts sequences are approximately 260 thousands.In order to speed up roster construction process shifts are grouped to four groups: morning shifts, day shifts, night shifts and duty shifts. There are only 64 feasible shifts sequences, in this case.After roster construction shift groups are replaced with the one of shift belonging to that group of shifts.When all shifts are added to roster, computation of workload for each schedule is performed. If computed workload is equal to the one defined in working contract, then this schedule is complete, else begin shifts revision process. During revision process those schedules are considered which do not meet work contract requirements.If computed workload is larger than the one defined in working contract, each shift is replaced with the shift, if it’s possible, with lesser duration time. If computed workload is lesser than the one defined in working contract, each shift is replaced with the shift, if it’s possible, with larger duration time.This process continues while schedule does not meet workload requirement defined in working contract or no further improvement can be made.Research limitations/implications—Problem dimension: 27 health care workers, 15 shifts, over 20 soft constraints, rostering period—one calendar month.Practical implications – modifications made to shift sequence based approach allows to construct a roster for one of the major Lithuania’s hospitals personnel in shorter time.Originality/Value—modification of shift sequence based approach is proposed.

Anthropometric changes and fluid shifts

Science.gov (United States)

Thornton, W. E.; Hoffler, G. W.; Rummel, J. A.

1974-01-01

Several observations of body size, shape, posture, and configuration were made to document changes resulting from direct effects of weightlessness during the Skylab 4 mission. After the crewmen were placed in orbit, a number of anatomical and anthropometric changes occurred including a straightening of the thoracolumbar spine, a general decrease in truncal girth, and an increase in height. By the time of the earliest in-flight measurement on mission day 3, all crewmen had lost more than two liters of extravascular fluid from the calf and thigh. The puffy facies, the bird legs effect, the engorgement of upper body veins, and the reduced volume of lower body veins were all documented with photographs. Center-of-mass measurements confirmed a fluid shift cephalad. This shift remained throughout the mission until recovery, when a sharp reversal occurred; a major portion of the reversal was completed in a few hours. The anatomical changes are of considerable scientific interest and of import to the human factors design engineer, but the shifts of blood and extravascular fluid are of more consequence. It is hypothesized that the driving force for the fluid shift is the intrinsic and unopposed lower limb elasticity that forces venous blood and then other fluid cephalad.

Canopy Modeling of Aquatic Vegetation: Construction of Submerged Vegetation Index

Science.gov (United States)

Ma, Z.; Zhou, G.

2018-04-01

The unique spectral characteristics of submerged vegetation in wetlands determine that the conventional terrestrial vegetation index cannot be directly employed to species identification and parameter inversion of submerged vegetation. Based on the Aquatic Vegetation Radiative Transfer model (AVRT), this paper attempts to construct an index suitable for submerged vegetation, the model simulated data and a scene of Sentinel-2A image in Taihu Lake, China are utilized for assessing the performance of the newly constructed indices and the existent vegetation indices. The results show that the angle index composed by 525 nm, 555 nm and 670 nm can resist the effects of water columns and is more sensitive to vegetation parameters such as LAI. Furthermore, it makes a well discrimination between submerged vegetation and water bodies in the satellite data. We hope that the new index will provide a theoretical basis for future research.

Current and future fire regimes and their influence on natural vegetation in Ethiopia

DEFF Research Database (Denmark)

van Breugel, Paulo; Friis, Ib; Demissew, Sebsebe

2016-01-01

vegetation types. The effect of climate change varies considerably between climate change models and scenarios, but as general trend expansions of moist Afromontane forest and Combretum–Terminalia woodlands were predicted. Fire-prone areas were also predicted to increase, and including this factor...... in vegetation distribution models resulted in stronger expansion of Combretum–Terminalia woodlands and a more limited increase of moist Afromontane forests. These results underline the importance of fire as a regulating factor of vegetation distribution patterns, and how fire needs to be factored into predict......Fire is a major factor shaping the distribution of vegetation types. In this study, we used a recent high resolution map of potential natural vegetation (PNV) types and MODIS fire products to model and investigate the importance of fire as driver of vegetation distribution patterns in Ethiopia. We...

Paradigm shift from cartography to geo-communication

DEFF Research Database (Denmark)

Brodersen, Lars

2007-01-01

This paper argues that the domain of GIS, cartography, geo-information etc. is facing a paradigm shift. The implication of a paradigm shift is a complete and necessary re-definition of e.g. the philosophical foundation of the system, as well as with a major upgrade and readjustment of procedures......-information is actually not possible at all without having a usage (a project identity and a purpose) in mind. Objective and neutral geo-information does not exist. Therefore the overall philosophy of the geo-domain will be that it is a communication discipline....

Impact of the Little Ice Age cooling and 20th century climate change on peatland vegetation dynamics in central and northern Alberta using a multi-proxy approach and high-resolution peat chronologies

Science.gov (United States)

Magnan, Gabriel; van Bellen, Simon; Davies, Lauren; Froese, Duane; Garneau, Michelle; Mullan-Boudreau, Gillian; Zaccone, Claudio; Shotyk, William

2018-04-01

Northern boreal peatlands are major terrestrial sinks of organic carbon and these ecosystems, which are highly sensitive to human activities and climate change, act as sensitive archives of past environmental change at various timescales. This study aims at understanding how the climate changes of the last 1000 years have affected peatland vegetation dynamics in the boreal region of Alberta in western Canada. Peat cores were collected from five bogs in the Fort McMurray region (56-57° N), at the southern limit of sporadic permafrost, and two in central Alberta (53° N and 55° N) outside the present-day limit of permafrost peatlands. The past changes in vegetation communities were reconstructed using detailed plant macrofossil analyses combined with high-resolution peat chronologies (14C, atmospheric bomb-pulse 14C, 210Pb and cryptotephras). Peat humification proxies (C/N, H/C, bulk density) and records of pH and ash content were also used to improve the interpretation of climate-related vegetation changes. Our study shows important changes in peatland vegetation and physical and chemical peat properties during the Little Ice Age (LIA) cooling period mainly from around 1700 CE and the subsequent climate warming of the 20th century. In some bogs, the plant macrofossils have recorded periods of permafrost aggradation during the LIA with drier surface conditions, increased peat humification and high abundance of ericaceous shrubs and black spruce (Picea mariana). The subsequent permafrost thaw was characterized by a short-term shift towards wetter conditions (Sphagnum sect. Cuspidata) and a decline in Picea mariana. Finally, a shift to a dominance of Sphagnum sect. Acutifolia (mainly Sphagnum fuscum) occurred in all the bogs during the second half of the 20th century, indicating the establishment of dry ombrotrophic conditions under the recent warmer and drier climate conditions.

Marshes on the Move: Testing effects of seawater intrusion on vegetation communities of the salt marsh-upland ecotone

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The Northeastern United States is a hotspot for sea level rise (SLR), subjecting coastal salt marshes to erosive loss, shifts in vegetation communities, and altered biogeochemistry due to seawater intrusion. Salt marsh plant community zonation is driven by tradeoffs in stress to...

Productive vegetation: relationships between net primary productivity, vegetation types and climate change in the Wet Tropics bioregion

International Nuclear Information System (INIS)

Ramirez, Vanessa Valdez; Williams, Stephen E.; VanDerWal, Jeremy

2007-01-01

Full text: Full text: There is now ample evidence demonstrating the impacts of climate change on biodiversity and human society (Walther ef a/. 2002). Numerous studies have shown climate change is one of the most significant threats to tropical forests, such as the Wet Tropics Heritage Area, due to their high biodiversity and endemism (Pounds ef al. 1999; Hughes 2000; Parmesan and Yohe 2003). Williams ef al. (2003) suggested that small shifts in net primary productivity (NPP) as a result of climate change could lead to potentially massive follow-on effects for the extremely diverse and vulnerable rainforest flora and fauna. It is therefore crucial to explore the relationships between NPP and local biodiversity, especially to create models for different climate change scenarios. Nevertheless, NPP in the Wet Tropics has yet to be estimated. This is the first study to provide a general NPP estimate for the Wet Tropics bioregion using climate surrogates (Schuur 2003). This technique estimates NPP in an accurate, repeatable, and cost-effective way. NPP values were linked to vegetation types and examined under various climatic and environmental conditions. Results show a significant difference in productivity according to vegetation types and climatic variables, with temperature and rainfall seasonality as the most important determining variables. Additionally, lowland and upland vegetations showed a significant difference in productivity patterns throughout the year. Vegetation types located above 1000 metres in altitude had the lowest values of mean annual productivity due to their high rainfall and low temperatures; vegetation types located below 600 metres showed increased productivity values during the wet season (December-March). Net primary productivity will certainly be impacted by changes in temperature and rainfall, due to climate change. Although an increase in NPP values can be predicted for upland areas, the more widely distributed lowlands will drastically

Vegetation-climate feedbacks modulate rainfall patterns in Africa under future climate change

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Wu, Minchao; Schurgers, Guy; Rummukainen, Markku; Smith, Benjamin; Samuelsson, Patrick; Jansson, Christer; Siltberg, Joe; May, Wilhelm

2016-07-01

Africa has been undergoing significant changes in climate and vegetation in recent decades, and continued changes may be expected over this century. Vegetation cover and composition impose important influences on the regional climate in Africa. Climate-driven changes in vegetation structure and the distribution of forests versus savannah and grassland may feed back to climate via shifts in the surface energy balance, hydrological cycle and resultant effects on surface pressure and larger-scale atmospheric circulation. We used a regional Earth system model incorporating interactive vegetation-atmosphere coupling to investigate the potential role of vegetation-mediated biophysical feedbacks on climate dynamics in Africa in an RCP8.5-based future climate scenario. The model was applied at high resolution (0.44 × 0.44°) for the CORDEX-Africa domain with boundary conditions from the CanESM2 general circulation model. We found that increased tree cover and leaf-area index (LAI) associated with a CO2 and climate-driven increase in net primary productivity, particularly over subtropical savannah areas, not only imposed important local effect on the regional climate by altering surface energy fluxes but also resulted in remote effects over central Africa by modulating the land-ocean temperature contrast, Atlantic Walker circulation and moisture inflow feeding the central African tropical rainforest region with precipitation. The vegetation-mediated feedbacks were in general negative with respect to temperature, dampening the warming trend simulated in the absence of feedbacks, and positive with respect to precipitation, enhancing rainfall reduction over the rainforest areas. Our results highlight the importance of accounting for vegetation-atmosphere interactions in climate projections for tropical and subtropical Africa.

CYCLICAL MANNER OF VEGETABLE PRODUCTION INDUSTRY; THE EFFICIENCY OF GREENHOUSE BUSINESS

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O. N. Krylov

2017-01-01

Full Text Available Economical  efficiency  of  agricultural  industry  is  a major characteristic of the level of development of an enterprise. A profit from product sale depends on volume and structure of product  sales, self-cost as well as the level of  sales price.  Thus, the gross revenue from cultivated crops and vegetable cultivars can be observed at the time of fruit harvesting. The total sum of  the gross earnings from  the harvest, determining the  efficiency  of  enterprise can  be  calculated  as a product of values of daily price and mass of total harvest. There are no challenging points in the condition of permanent price and vegetable harvest. Even the registration of average-sales prices for vegetable doesn’t make the production difficult. But real market situation essentially differs from accepted practice to register average-sales prices with relatively permanent vegetable  harvest.  The  price  indexes  of  sales  for tomato and cucumber produced in greenhouse in Udmurt Republic with showing the dynamic of retail price for vegetables were presented in the article. It was shown  that  prices  of  tomatoes  and cucumbers had the seasonal factor that meant weekly price wavering.  The  temporal  row  harvest  of  cucumber ‘Tseres           F1’  and  tomato  ‘Admiro  F1’  produced  at Zaviyalovskiy greenhouse enterprise was  described. The average derivation between nearest and last harvest was in the  gap  23%  to  29%  in cucumber  and reached up to 70% in tomato. The values of such derivations were occasionally provoked and determined by some inter-enterprise factors. The construction  of trend lines for such series and further line evaluation with  the aid of  determination  coefficient  R2  showed extremely low quality of model  of the kind y=a•x+b. The value of R2 cubic  polynominals was in the limits R2=0.32-0.46. Essentially, plans for vegetable production

Response of testate amoebae to a late Holocene ecosystem shift in an Amazonian peatland.

Science.gov (United States)

Swindles, Graeme T; Kelly, Thomas J; Roucoux, Katherine H; Lawson, Ian T

2018-03-15

To date there have only been two studies using testate amoebae as palaeoecological indicators in tropical peatlands. Here we present a new ∼500-year testate amoeba record from San Jorge, a domed peatland in Peruvian Amazonia, which has a well-constrained vegetation history based on pollen analysis. We observe a major shift from Hyalosphenia subflava to Cryptodifflugia oviformis-dominated communities at ∼50 cm depth (c. AD 1760), which suggests a change to drier conditions in the peatland. The application of a statistical transfer function also suggests a deepening of the water table at this time. The transition in the microbial assemblage occurs at a time when pollen and geochemical data indicate drier conditions (reduced influence of river flooding), leading to an ecosystem switch to more ombrotrophic-like conditions in the peatland. Our work illustrates the potential of testate amoebae as important tools in tropical peatland palaeoecology, and the power of multiproxy approaches for understanding the long-term development of tropical peatlands. Copyright © 2018 Elsevier GmbH. All rights reserved.

Shift Colors

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Publications & News Shift Colors Pages default Sign In NPC Logo Banner : Shift Colors Search Navy Personnel Command > Reference Library > Publications & News > Shift Colors Top Link Bar Navy Personnel Library Expand Reference Library Quick Launch Shift Colors Shift Colors Archives Mailing Address How to

Nutrient Density and the Cost of Vegetables from Elementary School Lunches123

Science.gov (United States)

Ishdorj, Ariun; Capps, Oral; Murano, Peter S

2016-01-01

Vegetables are the major source of the dietary fiber, magnesium, potassium, and vitamins A and C that are crucial in the diets of children. This study assessed the nutrient content of vegetables offered through the National School Lunch Program and examined the relation between the overall nutrient density of vegetable subgroups and the costs of nutrients offered and wasted before and after the changes in school meal standards. Using data collected from 3 elementary schools before and after the changes in school meal standards, we found that vegetable plate waste increased from 52% to 58%. Plate waste for starchy vegetables, exclusive of potatoes, was relatively high compared with other subgroups; however, plate waste for white potatoes was the lowest among any type of vegetable. Energy density; cost per 100 g, per serving, and per 100 kcal; and percentage daily value were calculated and used to estimate nutrient density value and nutrient density per dollar. Cost per 100 kcal was highest for red/orange vegetables followed by dark green vegetables; however, nutrient density for red/orange vegetables was the highest in the group and provided the most nutrients per dollar compared with other subgroups. Given that many vegetables are less energy dense, measuring vegetable costs per 100 g and per serving by accounting for nutrient density perhaps is a better way of calculating the cost of vegetables in school meals. PMID:26773034

Ergonomic workload and well-being of nurses working in shifts

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Kinga Dorota Kulczycka

2017-10-01

Conclusions Among the most common health problems, up to 63.5% of nurses declares chronic fatigue, 40.6% of cardiovascular problems, and 28.1% gastrointestinal disorders. Employees working in two shifts often have trouble sleeping, consisting of waking several times during the night, than who work in shift system. Physical activity and spending time with your family or loved ones reduces the frequency of problems. The vast majority (65.7% of respondents among shift workers, occupational exposure has been associated with an accident or work.

Unraveling the Shift to the Entrepreneurial Economy

NARCIS (Netherlands)

D.B. Audretsch (David); A.R. Thurik (Roy)

2010-01-01

textabstractA recent literature has emerged providing compelling evidence that a major shift in the organization of the developed economies has been taking place: away from what has been characterized as the managed economy towards the entrepreneurial economy. In particular, the empirical evidence

Temporal shift of sea turtle nest sites in an eroding barrier island beach

Science.gov (United States)

Fujisaki, Ikuko; Lamont, Margaret M.; Carthy, Raymond R.

2018-01-01

Shoreline changes affect functionality of a sandy beach as a wildlife habitat and coastal erosion is among the primary causes of the changes. We examined temporal shifts in locations where loggerheads placed nests in relation to coastal erosion along a barrier island beach in the northern Gulf of Mexico. We first confirmed consistency in long-term (1855–2001), short-term (1976–2001), and more recent (2002–2012) shoreline change rates in two adjacent beach sections, one historically eroding (west beach) and the other accreting (east beach). The mean annual shoreline change rate in the two sections was significantly different in all time periods. The recent (1998–2012) mean change rate was −10.9 ± 9.9 m/year in the west beach and −2.8 ± 4.9 m/year in the east beach, which resulted in the loss of about 70% and 30% of area in the west and east beaches, respectively. Loggerheads nested significantly closer to the vegetation line in 2012 than in 2002 in the west beach but the difference between the two time periods was not significant in the east beach. However, the distance from nests to the vegetation line from 2002 to 2014 was significantly reduced annually in both beaches; on average, loggerheads nested closer to the vegetation line by 9 m/year in the west beach and 5.8 m/year in the east beach. The observed shoreline change rate and corresponding shift of nest placement sites, combined with the forecasted future beach loss, highlighted the importance of addressing the issue of beach erosion to conserve sandy beach habitats.

Vegetation dynamics and dynamic vegetation science

NARCIS (Netherlands)

Van der Maarel, E

1996-01-01

his contribution presents a review of the development of the study of vegetation dynamics since 1979, in the framework of a jubilee meeting on progress in the study of vegetation. However, an exhaustive review is both impossible and unnecessary. It is impossible within the few pages available

Quantitative indicators of fruit and vegetable consumption

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Dagmar Kozelová

2015-12-01

Full Text Available The quantitative research of the market is often based on surveys and questionnaires which are finding out the behavior of customers in observed areas. Before purchasing process consumers consider where they will buy fruit and vegetables, what kind to choose and in what quantity of goods. Consumers' behavior is affected by the factors as: regional gastronomic traditions, price, product appearance, aroma, place of buying, own experience and knowledge, taste preferences as well as specific health issues of consumers and others. The consumption of fruit and vegetables brings into the human body biological active substances that favorably affect the health of consumers. In the presented research study we were interested in differences of consumers' behavior in the consumption of fruit and vegetables according to the place of residence and gender. In the survey 200 respondents has participated; their place of residence was city or village. The existence of dependences and statistical significance were examined by selected statistical testing methods. Firstly we analyzed the responses via statistical F-test whether observed random samples have the same variance. Then we applied two-sample unpaired t-test with equal variance and χ2-test of statistical independence. The statistical significance was tested by corresponding p values. Correlations were proved by the Cramer's V coefficient. We found that place of residence has no impact on the respondents' consumption of fruit. The gender of respondents does not affect their consumption of fruit. Equally, the gender does not affect the respondents' consumption of vegetables. Only in one observed case the significant differences proved that the place of respondent residence has impact on the consumption of vegetables. Higher consumption of vegetables is due to the fact that the majority of citizens, who live in villages, have a possibility to grow their own vegetables and, thus, the demand for it in village

Vegetation survey: a new focus for Applied Vegetation Science

NARCIS (Netherlands)

Chytry, M.; Schaminee, J.H.J.; Schwabe, A.

2011-01-01

Vegetation survey is an important research agenda in vegetation science. It defines vegetation types and helps understand differences among them, which is essential for both basic ecological research and applications in biodiversity conservation and environmental monitoring. In this editorial, we

Beyond the fragmentation threshold hypothesis: regime shifts in biodiversity across fragmented landscapes.

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Renata Pardini

Full Text Available Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andrén proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions--that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework

Rescuing and Sharing Historical Vegetation Data for Ecological Analysis: The California Vegetation Type Mapping Project

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Maggi Kelly

2016-10-01

Full Text Available Research efforts that synthesize historical and contemporary ecological data with modeling approaches improve our understanding of the complex response of species, communities, and landscapes to changing biophysical conditions through time and in space. Historical ecological data are particularly important in this respect. There are remaining barriers that limit such data synthesis, and technological improvements that make multiple diverse datasets more readily available for integration and synthesis are needed. This paper presents one case study of the Wieslander Vegetation Type Mapping project in California and highlights the importance of rescuing, digitizing and sharing historical datasets. We review the varied ecological uses of the historical collection: the vegetation maps have been used to understand legacies of land use change and plan for the future; the plot data have been used to examine changes to chaparral and forest communities around the state and to predict community structure and shifts under a changing climate; the photographs have been used to understand changing vegetation structure; and the voucher specimens in combination with other specimen collections have been used for large scale distribution modeling efforts. The digitization and sharing of the data via the web has broadened the scope and scale of the types of analysis performed. Yet, additional research avenues can be pursued using multiple types of VTM data, and by linking VTM data with contemporary data. The digital VTM collection is an example of a data infrastructure that expands the potential of large scale research through the integration and synthesis of data drawn from numerous data sources; its journey from analog to digital is a cautionary tale of the importance of finding historical data, digitizing it with best practices, linking it with other datasets, and sharing it with the research community.

Shifts in Arctic phenology in response to climate and anthropogenic factors as detected from multiple satellite time series

International Nuclear Information System (INIS)

Zeng, Heqing; Jia, Gensuo; Forbes, Bruce C

2013-01-01

There is an urgent need to reduce the uncertainties in remotely sensed detection of phenological shifts of high latitude ecosystems in response to climate changes in past decades. In this study, vegetation phenology in western Arctic Russia (the Yamal Peninsula) was investigated by analyzing and comparing Normalized Difference Vegetation Index (NDVI) time series derived from the Advanced Very High Resolution Radiometer (AVHRR), the Moderate Resolution Imaging Spectroradiometer (MODIS), and SPOT-Vegetation (VGT) during the decade 2000–2010. The spatial patterns of key phenological parameters were highly heterogeneous along the latitudinal gradients based on multi-satellite data. There was earlier SOS (start of the growing season), later EOS (end of the growing season), longer LOS (length of the growing season), and greater MaxNDVI from north to south in the region. The results based on MODIS and VGT data showed similar trends in phenological changes from 2000 to 2010, while quite a different trend was found based on AVHRR data from 2000 to 2008. A significantly delayed EOS (p < 0.01), thus increasing the LOS, was found from AVHRR data, while no similar trends were detected from MODIS and VGT data. There were no obvious shifts in MaxNDVI during the last decade. MODIS and VGT data were considered to be preferred data for monitoring vegetation phenology in northern high latitudes. Temperature is still a key factor controlling spatial phenological gradients and variability, while anthropogenic factors (reindeer husbandry and resource exploitation) might explain the delayed SOS in southern Yamal. Continuous environmental damage could trigger a positive feedback to the delayed SOS. (letter)

Lanthanide shift reagents, binding, shift mechanisms and exchange

International Nuclear Information System (INIS)

Boer, J.W.M. de

1977-01-01

Paramagnetic lanthanide shift reagents, when added to a solution of a substrate, induce shifts in the nuclear magnetic resonance (NMR) spectrum of the substrate molecules. The induced shifts contain information about the structure of the shift reagent substrate complex. The structural information, however, may be difficult to extract because of the following effects: (1) different complexes between shift reagent and substrate may be present in solution, e.g. 1:1 and 1:2 complexes, and the shift observed is a weighed average of the shifts of the substrate nuclei in the different complexes; (2) the Fermi contact interaction, arising from the spin density at the nucleus, contributes to the induced shift; (3) chemical exchange effects may complicate the NMR spectrum. In this thesis, the results of an investigation into the influence of these effects on the NMR spectra of solutions containing a substrate and LSR are presented. The equations describing the pseudo contact and the Fermi contact shift are derived. In addition, it is shown how the modified Bloch equations describing the effect of the chemical exchange processes occurring in the systems studied can be reduced to the familiar equations for a two-site exchange case. The binding of mono- and bifunctional ethers to the shift reagent are reported. An analysis of the induced shifts is given. Finally, the results of the experiments performed to study the exchange behavior of dimethoxyethane and heptafluorodimethyloctanedionato ligands are presented

A vital link: water and vegetation in the Anthropocene

Directory of Open Access Journals (Sweden)

D. Gerten

2013-10-01

Full Text Available This paper argues that the interplay of water, carbon and vegetation dynamics fundamentally links some global trends in the current and conceivable future Anthropocene, such as cropland expansion, freshwater use, and climate change and its impacts. Based on a review of recent literature including geographically explicit simulation studies with the process-based LPJmL global biosphere model, it demonstrates that the connectivity of water and vegetation dynamics is vital for water security, food security and (terrestrial ecosystem dynamics alike. The water limitation of net primary production of both natural and agricultural plants – already pronounced in many regions – is shown to increase in many places under projected climate change, though this development is partially offset by water-saving direct CO2 effects. Natural vegetation can to some degree adapt dynamically to higher water limitation, but agricultural crops usually require some form of active management to overcome it – among them irrigation, soil conservation and eventually shifts of cropland to areas that are less water-limited due to more favourable climatic conditions. While crucial to secure food production for a growing world population, such human interventions in water–vegetation systems have, as also shown, repercussions on the water cycle. Indeed, land use changes are shown to be the second-most important influence on the terrestrial water balance in recent times. Furthermore, climate change (warming and precipitation changes will in many regions increase irrigation demand and decrease water availability, impeding rainfed and irrigated food production (if not CO2 effects counterbalance this impact – which is unlikely at least in poorly managed systems. Drawing from these exemplary investigations, some research perspectives on how to further improve our knowledge of human–water–vegetation interactions in the Anthropocene are outlined.

Hydrological regulation drives regime shifts: evidence from paleolimnology and ecosystem modeling of a large shallow Chinese lake.

Science.gov (United States)

Kong, Xiangzhen; He, Qishuang; Yang, Bin; He, Wei; Xu, Fuliu; Janssen, Annette B G; Kuiper, Jan J; van Gerven, Luuk P A; Qin, Ning; Jiang, Yujiao; Liu, Wenxiu; Yang, Chen; Bai, Zelin; Zhang, Min; Kong, Fanxiang; Janse, Jan H; Mooij, Wolf M

2017-02-01

Quantitative evidence of sudden shifts in ecological structure and function in large shallow lakes is rare, even though they provide essential benefits to society. Such 'regime shifts' can be driven by human activities which degrade ecological stability including water level control (WLC) and nutrient loading. Interactions between WLC and nutrient loading on the long-term dynamics of shallow lake ecosystems are, however, often overlooked and largely underestimated, which has hampered the effectiveness of lake management. Here, we focus on a large shallow lake (Lake Chaohu) located in one of the most densely populated areas in China, the lower Yangtze River floodplain, which has undergone both WLC and increasing nutrient loading over the last several decades. We applied a novel methodology that combines consistent evidence from both paleolimnological records and ecosystem modeling to overcome the hurdle of data insufficiency and to unravel the drivers and underlying mechanisms in ecosystem dynamics. We identified the occurrence of two regime shifts: one in 1963, characterized by the abrupt disappearance of submerged vegetation, and another around 1980, with strong algal blooms being observed thereafter. Using model scenarios, we further disentangled the roles of WLC and nutrient loading, showing that the 1963 shift was predominantly triggered by WLC, whereas the shift ca. 1980 was attributed to aggravated nutrient loading. Our analysis also shows interactions between these two stressors. Compared to the dynamics driven by nutrient loading alone, WLC reduced the critical P loading and resulted in earlier disappearance of submerged vegetation and emergence of algal blooms by approximately 26 and 10 years, respectively. Overall, our study reveals the significant role of hydrological regulation in driving shallow lake ecosystem dynamics, and it highlights the urgency of using multi-objective management criteria that includes ecological sustainability perspectives when

Increased self-efficacy for vegetable preparation following an online, skill-based intervention and in-class tasting experience as a part of a general education college nutrition course.

Science.gov (United States)

Brown, Katie N; Wengreen, Heidi J; Vitale, Tamara S; Anderson, Janet B

2011-01-01

Assess the effectiveness of the integration of vegetable demonstration videos and tasting experiences into a college nutrition course to influence students' readiness to change vegetable intake, self-efficacy for vegetable preparation, and usual vegetable intake. Quasiexperimental, preintervention-postintervention comparisons. College nutrition course. Of the 376 students enrolled in the course, 186 completed the online assessments (145 female, 41 male; mean age, 20 years). Participants viewed online vegetable preparation videos and participated in vegetable tasting experiences that featured four target vegetables, one vegetable each month for 4 months. Preintervention and postintervention online surveys determined usual vegetable intake, readiness to change vegetable consumption, and self-efficacy of vegetable preparation. Chi-square distribution and paired sample t-tests were used to examine differences preintervention and postintervention. Stage of readiness to change vegetable intake shifted from contemplation toward preparation (p Online vegetable demonstration videos may be an effective and cost-efficient intervention for increasing self-efficacy of vegetable preparation and readiness to increase vegetable consumption among college students. More research is needed to determine long-term effects on vegetable consumption.

Tilt shift determinations with spatial-carrier phase-shift method in temporal phase-shift interferometry

International Nuclear Information System (INIS)

Liu, Qian; Wang, Yang; He, Jianguo; Ji, Fang; Wang, Baorui

2014-01-01

An algorithm is proposed to deal with tilt-shift errors in temporal phase-shift interferometry (PSI). In the algorithm, the tilt shifts are detected with the spatial-carrier phase-shift (SCPS) method and then the tilt shifts are applied as priori information to the least-squares fittings of phase retrieval. The algorithm combines the best features of the SCPS and the temporal PSI. The algorithm could be applied to interferograms of arbitrary aperture without data extrapolation for the Fourier transform is not involved. Simulations and experiments demonstrate the effectiveness of the algorithm. The statistics of simulation results show a satisfied accuracy in detecting tilt-shift errors. Comparisons of the measurements with and without environmental vibration show that the proposed algorithm could compensate tilt-shift errors and retrieve wavefront phase accurately. The algorithm provides an approach to retrieve wavefront phase for the temporal PSI in vibrating environment. (paper)

Written Language Shift among Norwegian Youth

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Kamil ÖZERK

2013-07-01

Full Text Available In Norway there are two written Norwegian languages, Bokmål and Nynorsk. Of these two written languages Bokmål is being used by the majority of the people, and Bokmål has the highest prestige in the society. This article is about the shift of written language from Nynorsk to Bokmål among young people in a traditional Nynorsk district in the country. Drawing on empirical data we conclude that many adolescents are experiencing written language shift. We discuss various reasons for this phenomenon in the linguistic landscape of Norway. In our discussions we emphasize the importance of the school with regard to language maintenance and language revitalization. We call for a new language policy in the educational system that can prevent language shift. Having several dialects and two officially written forms of Norwegian in the country, creates a special linguistic landscape in Norway. Despite the fact that the Norwegian language situation is in several ways unique, it’s done very little research on how the existing policy works in practice. Our research reveals that the existing language policy and practice in the school system is not powerful enough to prevent language shift and language decay among the youngsters. The school system functions like a fabric for language shift.

Cumulative drought and land-use impacts on perennial vegetation across a North American dryland region

Science.gov (United States)

Munson, Seth M.; Long, A. Lexine; Wallace, Cynthia; Webb, Robert H.

2016-01-01

Question The decline and loss of perennial vegetation in dryland ecosystems due to global change pressures can alter ecosystem properties and initiate land degradation processes. We tracked changes of perennial vegetation using remote sensing to address the question of how prolonged drought and land-use intensification have affected perennial vegetation cover across a desert region in the early 21st century? Location Mojave Desert, southeastern California, southern Nevada, southwestern Utah and northwestern Arizona, USA. Methods We coupled the Moderate-Resolution Imaging Spectroradiometer Enhanced Vegetation Index (MODIS-EVI) with ground-based measurements of perennial vegetation cover taken in about 2000 and about 2010. Using the difference between these years, we determined perennial vegetation changes in the early 21st century and related these shifts to climate, soil and landscape properties, and patterns of land use. Results We found a good fit between MODIS-EVI and perennial vegetation cover (2000: R2 = 0.83 and 2010: R2 = 0.74). The southwestern, far southeastern and central Mojave Desert had large declines in perennial vegetation cover in the early 21st century, while the northeastern and southeastern portions of the desert had increases. These changes were explained by 10-yr precipitation anomalies, particularly in the cool season and during extreme dry or wet years. Areas heavily impacted by visitor use or wildfire lost perennial vegetation cover, and vegetation in protected areas increased to a greater degree than in unprotected areas. Conclusions We find that we can extrapolate previously documented declines of perennial plant cover to an entire desert, and demonstrate that prolonged water shortages coupled with land-use intensification create identifiable patterns of vegetation change in dryland regions.

Advances in monitoring vegetation and land use dynamics in the Sahel

DEFF Research Database (Denmark)

Mbow, Cheikh; Fensholt, Rasmus; Nielsen, Thomas Theis

2014-01-01

of CO2 in the atmosphere, grazing pressure, bush fires and agricultural expansion or contraction. The use of satellite data in combination with field data played a major role in the monitoring of vegetation dynamics and land use in the Sahel, since the mega drought of the 1970s and the 1980s. This paper...... briefly reviews the advance of satellite-based monitoring of vegetation dynamics over these 40 years. We discuss the promises of current and likely future data sources and analysis tools, as well as the need to strengthen in situ data collection to support and validate satellite-based vegetation and land...

Serving vegetables first: A strategy to increase vegetable consumption in elementary school cafeterias.

Science.gov (United States)

Elsbernd, S L; Reicks, M M; Mann, T L; Redden, J P; Mykerezi, E; Vickers, Z M

2016-01-01

Vegetable consumption in the United States is low despite the wealth of evidence that vegetables play an important role in reducing risk of various chronic diseases. Because eating patterns developed in childhood continue through adulthood, we need to form healthy eating habits in children. The objective of this study was to determine if offering vegetables before other meal components would increase the overall consumption of vegetables at school lunch. We served kindergarten through fifth-grade students a small portion (26-33 g) of a raw vegetable (red and yellow bell peppers) while they waited in line to receive the rest of their lunch meal. They then had the options to take more of the bell peppers, a different vegetable, or no vegetable from the lunch line. We measured the amount of each vegetable consumed by each child. Serving vegetables first greatly increased the number of students eating vegetables. On intervention days most of the vegetables consumed came from the vegetables-first portions. Total vegetable intake per student eating lunch was low because most students chose to not eat vegetables, but the intervention significantly increased this value. Serving vegetables first is a viable strategy to increase vegetable consumption in elementary schools. Long-term implementation of this strategy may have an important impact on healthy eating habits, vegetable consumption, and the health consequences of vegetable intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modelling post-fire vegetation recovery in Portugal

Directory of Open Access Journals (Sweden)

A. Bastos

2011-12-01

Full Text Available Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion.

The main goals of the present work are (i to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively.

The study relies on monthly values of NDVI over 11 years (1998–2009, at 1 km × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus pinaster over the area, and by the fact that coniferous forests tend to

Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient.

Science.gov (United States)

Becklin, Katie M; Mullinix, George W R; Ward, Joy K

2016-10-01

Rising atmospheric carbon dioxide concentration ([CO 2 ]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO 2 ] gradient (180-1,000 µL L -1 ). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO 2 ] and arbuscular mycorrhizal fungi. To evaluate [CO 2 ] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (M Bio ) and nonmycorrhizal (NM Bio ) plants (R Bio = [M Bio - NM Bio ]/NM Bio ). We then assessed linkages between R Bio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, R Bio increased with rising [CO 2 ], shifting from negative to positive values at 700 µL L -1 [CO 2 ] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in R Bio in this species. For T. ceratophorum, R Bio increased from 180 to 390 µL L -1 and further increases in [CO 2 ] caused R Bio to shift from positive to negative values. [CO 2 ] and fungal effects on plant growth and carbon sink strength were correlated with shifts in R Bio in this species. Overall, we show that rising [CO 2 ] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO 2 ], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO 2 ]. The magnitude and mechanisms driving mycorrhizal-CO 2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. © 2016 American Society of Plant Biologists. All Rights Reserved.

Simulating vegetation response to climate change in the Blue Mountains with MC2 dynamic global vegetation model

Directory of Open Access Journals (Sweden)

John B. Kim

2018-04-01

Full Text Available Warming temperatures are projected to greatly alter many forests in the Pacific Northwest. MC2 is a dynamic global vegetation model, a climate-aware, process-based, and gridded vegetation model. We calibrated and ran MC2 simulations for the Blue Mountains Ecoregion, Oregon, USA, at 30 arc-second spatial resolution. We calibrated MC2 using the best available spatial datasets from land managers. We ran future simulations using climate projections from four global circulation models (GCM under representative concentration pathway 8.5. Under this scenario, forest productivity is projected to increase as the growing season lengthens, and fire occurrence is projected to increase steeply throughout the century, with burned area peaking early- to mid-century. Subalpine forests are projected to disappear, and the coniferous forests to contract by 32.8%. Large portions of the dry and mesic forests are projected to convert to woodlands, unless precipitation were to increase. Low levels of change are projected for the Umatilla National Forest consistently across the four GCM’s. For the Wallowa-Whitman and the Malheur National Forest, forest conversions are projected to vary more across the four GCM-based simulations, reflecting high levels of uncertainty arising from climate. For simulations based on three of the four GCMs, sharply increased fire activity results in decreases in forest carbon stocks by the mid-century, and the fire activity catalyzes widespread biome shift across the study area. We document the full cycle of a structured approach to calibrating and running MC2 for transparency and to serve as a template for applications of MC2. Keywords: Climate change, Regional change, Simulation, Calibration, Forests, Fire, Dynamic global vegetation model

Major shifts in Amazon wildlife populations from recent intensification of floods and drought.

Science.gov (United States)

Bodmer, Richard; Mayor, Pedro; Antunez, Miguel; Chota, Kimberlyn; Fang, Tula; Puertas, Pablo; Pittet, Marlini; Kirkland, Maire; Walkey, Mike; Rios, Claudia; Perez-Peña, Pedro; Henderson, Peter; Bodmer, William; Bicerra, Andy; Zegarra, Joseph; Docherty, Emma

2018-04-01

In the western Amazon Basin, recent intensification of river-level cycles has increased flooding during the wet seasons and decreased precipitation during the dry season. Greater than normal floods occurred in 2009 and in all years from 2011 to 2015 during high-water seasons, and a drought occurred during the 2010 low-water season. During these years, we surveyed populations of terrestrial, arboreal, and aquatic wildlife in a seasonally flooded Amazonian forest in the Loreto region of Peru (99,780 km 2 ) to study the effects of intensification of natural climatic fluctuations on wildlife populations and in turn effects on resource use by local people. Shifts in fish and terrestrial mammal populations occurred during consecutive years of high floods and the drought of 2010. As floods intensified, terrestrial mammal populations decreased by 95%. Fish, waterfowl, and otter (Pteronura brasiliensis) abundances increased during years of intensive floods, whereas river dolphin and caiman populations had stable abundances. Arboreal species, including, macaws, game birds, primates, felids, and other arboreal mammals had stable populations and were not affected directly by high floods. The drought of 2010 had the opposite effect: fish, waterfowl, and dolphin populations decreased, and populations of terrestrial and arboreal species remained stable. Ungulates and large rodents are important sources of food and income for local people, and large declines in these animals has shifted resource use of people living in the flooded forests away from hunting to a greater reliance on fish. © 2017 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Major Shifts in Glial Regional Identity Are a Transcriptional Hallmark of Human Brain Aging

OpenAIRE

Soreq, Lilach; Rose, Jamie; Soreq, Eyal; Hardy, John; Trabzuni, Daniah; Cookson, Mark R.; Smith, Colin; Ryten, Mina; Patani, Rickie; Ule, Jernej

2017-01-01

Summary Gene expression studies suggest that aging of the human brain is determined by a complex interplay of molecular events, although both its region- and cell-type-specific consequences remain poorly understood. Here, we extensively characterized aging-altered gene expression changes across ten human brain regions from 480 individuals ranging in?age from 16 to 106 years. We show that astrocyte-?and oligodendrocyte-specific genes, but not neuron-specific genes, shift their regional express...

Management of soil-borne diseases of organic vegetables

Directory of Open Access Journals (Sweden)

Shafique Hafiza Asma

2016-07-01

Full Text Available With the rising awareness of the adverse effects of chemical pesticides, people are looking for organically grown vegetables. Consumers are increasingly choosing organic foods due to the perception that they are healthier than those conventionally grown. Vegetable crops are vulnerable to a range of pathogenic organisms that reduce yield by killing the plant or damaging the product, thus making it unmarketable. Soil-borne diseases are among the major factors contributing to low yields of organic produce. Apart from chemical pesticides there are several methods that can be used to protect crops from soil-borne pathogens. These include the introduction of biocontrol agents against soil-borne plant pathogens, plants with therapeutic effects and organic soil amendments that stimulate antagonistic activities of microorganisms to soil-borne diseases. The decomposition of organic matter in soil also results in the accumulation of specific compounds that may be antifungal or nematicidal. With the growing interest in organic vegetables, it is necessary to find non chemical means of plant disease control. This review describes the impact of soil-borne diseases on organic vegetables and methods used for their control.

Gradient Analysis and Classification of Carolina Bay Vegetation: A Framework for Bay Wetlands Conservation and Restoration

Energy Technology Data Exchange (ETDEWEB)

Diane De Steven,Ph.D.; Maureen Tone,PhD.

1997-10-01

This report address four project objectives: (1) Gradient model of Carolina bay vegetation on the SRS--The authors use ordination analyses to identify environmental and landscape factors that are correlated with vegetation composition. Significant factors can provide a framework for site-based conservation of existing diversity, and they may also be useful site predictors for potential vegetation in bay restorations. (2) Regional analysis of Carolina bay vegetation diversity--They expand the ordination analyses to assess the degree to which SRS bays encompass the range of vegetation diversity found in the regional landscape of South Carolina's western Upper Coastal Plain. Such comparisons can indicate floristic status relative to regional potentials and identify missing species or community elements that might be re-introduced or restored. (3) Classification of vegetation communities in Upper Coastal Plain bays--They use cluster analysis to identify plant community-types at the regional scale, and explore how this classification may be functional with respect to significant environmental and landscape factors. An environmentally-based classification at the whole-bay level can provide a system of templates for managing bays as individual units and for restoring bays to desired plant communities. (4) Qualitative model for bay vegetation dynamics--They analyze present-day vegetation in relation to historic land uses and disturbances. The distinctive history of SRS bays provides the possibility of assessing pathways of post-disturbance succession. They attempt to develop a coarse-scale model of vegetation shifts in response to changing site factors; such qualitative models can provide a basis for suggesting management interventions that may be needed to maintain desired vegetation in protected or restored bays.

Late-glacial and Holocene Vegetation and Climate Variability, Including Major Droughts, in the Sky Lakes Region of Southeastern New York State

Science.gov (United States)

Menking, Kirsten M.; Peteet, Dorothy M.; Anderson, Roger Y.

2012-01-01

Sediment cores from Lakes Minnewaska and Mohonk in the Shawangunk Mountains of southeastern New York were analyzed for pollen, plantmacrofossils, macroscopic charcoal, organic carbon content, carbon isotopic composition, carbon/nitrogen ratio, and lithologic changes to determine the vegetation and landscape history of the greater Catskill Mountain region since deglaciation. Pollen stratigraphy generally matches the New England pollen zones identified by Deevey (1939) and Davis (1969), with boreal genera (Picea, Abies) present during the late Pleistocene yielding to a mixed Pinus, Quercus and Tsuga forest in the early Holocene. Lake Minnewaska sediments record the Younger Dryas and possibly the 8.2 cal kyr BP climatic events in pollen and sediment chemistry along with an 1400 cal yr interval of wet conditions (increasing Tsuga and declining Quercus) centered about 6400 cal yr BP. BothMinnewaska andMohonk reveal a protracted drought interval in themiddle Holocene, 5700-4100 cal yr BP, during which Pinus rigida colonized the watershed, lake levels fell, and frequent fires led to enhanced hillslope erosion. Together, the records show at least three wet-dry cycles throughout the Holocene and both similarities and differences to climate records in New England and central New York. Drought intervals raise concerns for water resources in the New York City metropolitan area and may reflect a combination of enhanced La Niña, negative phase NAO, and positive phase PNA climatic patterns and/or northward shifts of storm tracks.

Summary of the especies of Spanish vegetation sensitive to different pollutants

International Nuclear Information System (INIS)

Varela Gonzales, J.; Sanchez Cabrero, B.; Sanchez Gimeno, B.

1987-01-01

A detail literature review of the sensitivity of the species of Spanish vegetation to various pollutants was made. An impact scale was created to describe the qualitative degree of sensitivity to which each specie is affected by major atmospheric pollutants: very sensitive, sensitive, intermediate sensitive and resistent. This type of study, combined with studies of emission, concentration and dispersion of air pollution, is of great interest to evaluate the environmental impact to the vegetation community. (author) 45 refs

The oral bioavailability of nitrate from vegetables investigated in healthy volunteers

OpenAIRE

Lambers AC; Kortboyer JM; Schothorst RC; Sips AJAM; Cleven RFMJ; Meulenbelt J; VIC; LBM; ARO; LAC

2000-01-01

The major source of human nitrate exposure comes from vegetables. Several studies were performed to estimate the total daily dietary nitrate intake based on the nitrate contents of food and drinking water. However, only nitrate that is absorbed from the gastro-intestinal tract may contribute to the toxicity of nitrate in the body. At present no data are available on the bioavailability of nitrate from vegetables. Therefore the present study was performed to evaluate the oral bioavailability o...

An 11 000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley

Science.gov (United States)

Walsh, Megan K.; Pearl, Christopher A.; Whitlock, Cathy; Bartlein, Patrick J.; Worona, Marc A.

2010-01-01

High-resolution macroscopic charcoal and pollen analysis were used to reconstruct an 11??000-year-long record of fire and vegetation history from Beaver Lake, Oregon, the first complete Holocene paleoecological record from the floor of the Willamette Valley. In the early Holocene (ca 11??000-7500 calendar years before present [cal??yr??BP]), warmer, drier summers than at present led to the establishment of xeric woodland of Quercus, Corylus, and Pseudotsuga near the site. Disturbances (i.e., floods, fires) were common at this time and as a result Alnus rubra grew nearby. High fire frequency occurred in the early Holocene from ca 11??200-9300??cal??yr??BP. Riparian forest and wet prairie developed in the middle Holocene (ca 7500??cal??yr??BP), likely the result of a decrease in the frequency of flooding and a shift to effectively cooler, wetter conditions than before. The vegetation at Beaver Lake remained generally unchanged into the late Holocene (from 4000??cal??yr??BP to present), with the exception of land clearance associated with Euro-American settlement of the valley (ca 160??cal??yr BP). Middle-to-late Holocene increases in fire frequency, coupled with abrupt shifts in fire-episode magnitude and charcoal composition, likely indicate the influence anthropogenic burning near the site. The paleoecological record from Beaver Lake, and in particular the general increase in fire frequency over the last 8500??years, differs significantly from other low-elevation sites in the Pacific Northwest, which suggests that local controls (e.g., shifts in vegetation structure, intensification of human land-use), rather than regional climatic controls, more strongly influenced its environmental history. ?? 2010 Elsevier Ltd.

Fruit and vegetable consumption and risk of overall mortality and gastrointestinal cancer

OpenAIRE

Leenders, M.B.

2014-01-01

Fruits and vegetables are considered a major part of a healthy diet, because consumption increases satiety and reduces total energy intake by replacing more energy dense foods. In addition, they contain dietary fiber, vitamins, minerals and thousands of naturally occurring biologically active compounds (phytochemicals). A minimum consumption of 400 grams of fruits and vegetables per day is recommended to prevent noncommunicable diseases, such as cardiovascular disease, certain types of cancer...

Transition from Connected to Fragmented Vegetation across an Environmental Gradient: Scaling Laws in Ecotone Geometry.

Science.gov (United States)

Gastner, Michael T; Oborny, Beata; Zimmermann, D K; Pruessner, Gunnar

2009-07-01

A change in the environmental conditions across space-for example, altitude or latitude-can cause significant changes in the density of a vegetation type and, consequently, in spatial connectivity. We use spatially explicit simulations to study the transition from connected to fragmented vegetation. A static (gradient percolation) model is compared to dynamic (gradient contact process) models. Connectivity is characterized from the perspective of various species that use this vegetation type for habitat and differ in dispersal or migration range, that is, "step length" across the landscape. The boundary of connected vegetation delineated by a particular step length is termed the " hull edge." We found that for every step length and for every gradient, the hull edge is a fractal with dimension 7/4. The result is the same for different spatial models, suggesting that there are universal laws in ecotone geometry. To demonstrate that the model is applicable to real data, a hull edge of fractal dimension 7/4 is shown on a satellite image of a piñon-juniper woodland on a hillside. We propose to use the hull edge to define the boundary of a vegetation type unambiguously. This offers a new tool for detecting a shift of the boundary due to a climate change.

Phenology Shifts at Start vs. End of Growing Season in Temperate Vegetation Over the Northern Hemisphere for the Period 1982-2008

Science.gov (United States)

Jeong, Su-Jong; Ho, Chang-Hoi; Gim, Hyeon-Ju; Brown, Molley E.

2011-01-01

Changes in vegetative growing seasons are dominant indicators of the dynamic response of ecosystems to climate change. Therefore, knowledge of growing seasons over the past decades is essential to predict ecosystem changes. In this study, the long-term changes in the growing seasons of temperate vegetation over the Northern Hemisphere were examined by analyzing satellite-measured normalized difference vegetation index and reanalysis temperature during 1982 2008. Results showed that the length of the growing season (LOS) increased over the analysis period; however, the role of changes at the start of the growing season (SOS) and at the end of the growing season (EOS) differed depending on the time period. On a hemispheric scale, SOS advanced by 5.2 days in the early period (1982-1999) but advanced by only 0.2 days in the later period (2000-2008). EOS was delayed by 4.3 days in the early period, and it was further delayed by another 2.3 days in the later period. The difference between SOS and EOS in the later period was due to less warming during the preseason (January-April) before SOS compared with the magnitude of warming in the preseason (June September) before EOS. At a regional scale, delayed EOS in later periods was shown. In North America, EOS was delayed by 8.1 days in the early period and delayed by another 1.3 days in the later period. In Europe, the delayed EOS by 8.2 days was more significant than the advanced SOS by 3.2 days in the later period. However, in East Asia, the overall increase in LOS during the early period was weakened in the later period. Admitting regional heterogeneity, changes in hemispheric features suggest that the longer-lasting vegetation growth in recent decades can be attributed to extended leaf senescence in autumn rather than earlier spring leaf-out. Keywords: climate change, growing season, NDVI (normalized difference vegetation index), Northern Hemisphere, phenology,

Buying health: assessing the impact of a consumer-side vegetable subsidy on purchasing, consumption and waste.

Science.gov (United States)

Smith-Drelich, Noah

2016-02-01

To measure the impact of a reimbursement-based consumer subsidy on vegetable expenditures, consumption and waste. Two-arm randomized controlled trial; two-week baseline observation period, three-week intervention period. Participants' vegetable expenditures, consumption and waste were monitored using receipts collection and through an FFQ. During the intervention period, the treatment group received reimbursement of up to 50 US dollars ($) for purchased vegetables. Participants were solicited from Palo Alto, CA, USA using materials advertising a 'consumer behavior study' and a small participation incentive. To prevent selection bias, solicitation materials did not describe the specific behaviour being evaluated. One hundred and fifty potential participants responded to the solicitations and 144 participants enrolled in the study; 138 participants completed all five weekly surveys. Accounting for the control group (n 69) and the two-week baseline period, the intervention significantly impacted the treatment group's (n 69) vegetable expenditures (+$8.16 (sd 2.67)/week, Pconsumer subsidy significantly increased participants' vegetable expenditures, but not consumption or waste, suggesting that this type of subsidy might not have the effects anticipated. Reimbursement-based consumer subsidies may therefore not be as useful a policy tool for impacting vegetable consumption as earlier studies have suggested. Moreover, moderation analysis revealed that the subsidy's effect on participants' vegetable expenditures was significant only in men. Additional research should seek to determine how far reaching gender-specific effects are in this context. Further research should also examine the effect of a similar consumer subsidy on high-risk populations and explore to what extent increases in participants' expenditures are due to the purchase of more expensive vegetables, purchasing of vegetables during the study period that were consumed outside the study period, or a shift

Even low to medium nitrogen deposition impacts vegetation of dry, coastal dunes around the Baltic Sea

International Nuclear Information System (INIS)

Remke, Eva; Brouwer, Emiel; Kooijman, Annemieke; Blindow, Irmgard; Esselink, Hans; Roelofs, Jan G.M.

2009-01-01

Coastal dunes around the Baltic Sea have received small amounts of atmospheric nitrogen and are rather pristine ecosystems in this respect. In 19 investigated dune sites the atmospheric wet nitrogen deposition is 3-8 kg N ha -1 yr -1 . The nitrogen content of Cladonia portentosa appeared to be a suitable biomonitor of these low to medium deposition levels. Comparison with EMEP-deposition data showed that Cladonia reflects the deposition history of the last 3-6 years. With increasing nitrogen load, we observed a shift from lichen-rich short grass vegetation towards species-poor vegetation dominated by the tall graminoid Carex arenaria. Plant species richness per field site, however, does not decrease directly with these low to medium N deposition loads, but with change in vegetation composition. Critical loads for acidic, dry coastal dunes might be lower than previously thought, in the range of 4-6 kg N ha -1 yr -1 wet deposition. - Even low to medium nitrogen deposition impacts Baltic dune vegetation promoting a dominance of taller graminoids

Millennial-scale variability during the last glacial in vegetation records from North America

Science.gov (United States)

Jiménez-Moreno, Gonzalo; Anderson, R. Scott; Desprat, S.; Grigg, L.D.; Grimm, E.C.; Heusser, L.E.; Jacobs, Brian F.; Lopez-Martinez, C.; Whitlock, C.L.; Willard, D.A.

2010-01-01

High-resolution pollen records from North America show that terrestrial environments were affected by Dansgaard-Oeschger (D-O) and Heinrich climate variability during the last glacial. In the western, more mountainous regions, these climate changes are generally observed in the pollen records as altitudinal movements of climate-sensitive plant species, whereas in the southeast, they are recorded as latitudinal shifts in vegetation. Heinrich (HS) and Greenland (GS) stadials are generally correlated with cold and dry climate and Greenland interstadials (GI) with warm-wet phases. The pollen records from North America confirm that vegetation responds rapidly to millennial-scale climate variability, although the difficulties in establishing independent age models for the pollen records make determination of the absolute phasing of the records to surface temperatures in Greenland somewhat uncertain. ?? 2009 Elsevier Ltd.

INFLEXIBLE COGNITION PREDICTS FIRST ONSET OF MAJOR DEPRESSIVE EPISODES IN ADOLESCENCE.

Science.gov (United States)

Stange, Jonathan P; Connolly, Samantha L; Burke, Taylor A; Hamilton, Jessica L; Hamlat, Elissa J; Abramson, Lyn Y; Alloy, Lauren B

2016-04-19

Major depressive disorder often is characterized by a lack of cognitive and emotional flexibility, resulting in an impaired ability to adapt to situational demands. Adolescence is an important period of risk for the first onset of depression, yet relatively little is known about whether aspects of inflexibility, such as rumination and deficits in attentional shifting, could confer risk for the development of the disorder during this time. In the present study, a sample of 285 never-depressed adolescents completed self-report and behavioral measures of rumination and attentional shifting at a baseline visit, followed by up to 4 years of annual prospective follow-up diagnostic assessments. Survival analyses indicated that adolescents with greater levels of rumination or poorer attentional shifting experienced a shorter time until the first onset of major depressive episodes, even after accounting for baseline symptoms and demographic characteristics. Although girls were twice as likely as boys to experience the first onset of depression, rumination predicted a shorter time until depression onset only for boys. Rumination and attentional shifting were not correlated and predicted time until onset of major depression independently of one another. These results provide evidence that components of cognition that are characterized by rigidity and perseveration confer risk for the first onset of major depression during adolescence. Evaluating rumination and attentional shifting in adolescence may be useful in identifying individuals who are at risk for depression and who may benefit from interventions that target or alter the development of these characteristics. © 2016 Wiley Periodicals, Inc.

Suitability of vegetation for erosion control on uranium mill tailings: a regional analysis

International Nuclear Information System (INIS)

Beedlow, P.A.; McShane, M.C.

1983-11-01

Inactive uranium mill tailings (UMTRAP sites) in the West were grouped into three major climatic regions to evaluate the adequacy of vegetation for long-term stabilization: the Colorado Plateau, the West Slope of the Rocky Mountains, and the Northern Great Plains. Four general vegetation types were found at western sites: grasslands, shrub-steppe, and saltshrub and woodland. Soil-loss rates, calculated using the Universal Soil Loss Equation, were variable within regions and vegetation types, but trends were apparent. Calculations indicated that vegetation or vegetation plus a layer of surface rock provided adequate stabilization against long-term average soil loss for slopes less than 10% at the UMTRAP sites evaluated. However, detailed analyses of erosion due to severe storm events, gully formation and channel cutting is necessary for designing protective covers at each site. 11 references, 3 figures, 3 tables

Energy use pattern analyses of greenhouse vegetable production

Energy Technology Data Exchange (ETDEWEB)

Canakci, M.; Akinci, I. [Department of Agricultural Machinery, Faculty of Agriculture, Akdeniz University, 07070 Antalya (Turkey)

2006-07-15

Greenhouse farming is a growing industry in many states. It is a very expensive way to produce greenhouse crops and there are many variables to consider before the farmer decides to take this route. A good location is essential for crop planning and growing. However, current studies related to energy use patterns and resources present in vegetable production are very limited. This research attempts to investigate the energy use patterns in greenhouse vegetable production, to determine the energy output-input ratio and their relationships. Antalya province, which has greenhouse area of about 13,337ha (30.2%), is the center of greenhouse farming in Turkey. A questionnaire was distributed to 101 greenhouse farms from 11 villages in order to obtain the available data for vegetable production. Power requirement of the machines used in greenhouse operations were measured by using a computer based data acquisition system. Energy and economical variables (i.e. output-input ratio, specific energy, production cost, net return, etc.) were calculated by using the standard equations. As a result, the operational energy and energy source requirements of the greenhouse vegetable production were found between the ranges of 23,883.5-28,034.7 and 45,763.3-49,978.8MJ/1000m{sup 2}, respectively. The energy ratio of four major greenhouse vegetables-tomato, pepper, cucumber and eggplant-was 0.32, 0.19, 0.31, 0.23, respectively. The crop yields increased as a function of the total energy inputs with the best form being second-degree polynomial. The net return of the vegetable production was found in the 595.6-2775.3$/1000m{sup 2} ranges. Among the greenhouse vegetables, tomato cultivation resulted in being the most profitable. (author)

Spatial heterogeneity study of vegetation coverage at Heihe River Basin

Science.gov (United States)

Wu, Lijuan; Zhong, Bo; Guo, Liyu; Zhao, Xiangwei

2014-11-01

Spatial heterogeneity of the animal-landscape system has three major components: heterogeneity of resource distributions in the physical environment, heterogeneity of plant tissue chemistry, heterogeneity of movement modes by the animal. Furthermore, all three different types of heterogeneity interact each other and can either reinforce or offset one another, thereby affecting system stability and dynamics. In previous studies, the study areas are investigated by field sampling, which costs a large amount of manpower. In addition, uncertain in sampling affects the quality of field data, which leads to unsatisfactory results during the entire study. In this study, remote sensing data is used to guide the sampling for research on heterogeneity of vegetation coverage to avoid errors caused by randomness of field sampling. Semi-variance and fractal dimension analysis are used to analyze the spatial heterogeneity of vegetation coverage at Heihe River Basin. The spherical model with nugget is used to fit the semivariogram of vegetation coverage. Based on the experiment above, it is found, (1)there is a strong correlation between vegetation coverage and distance of vegetation populations within the range of 0-28051.3188m at Heihe River Basin, but the correlation loses suddenly when the distance greater than 28051.3188m. (2)The degree of spatial heterogeneity of vegetation coverage at Heihe River Basin is medium. (3)Spatial distribution variability of vegetation occurs mainly on small scales. (4)The degree of spatial autocorrelation is 72.29% between 25% and 75%, which means that spatial correlation of vegetation coverage at Heihe River Basin is medium high.

Vegetable oils as fuels and lubrificants: Commercialization problematics

International Nuclear Information System (INIS)

Bartolelli, V.

1992-01-01

The aim of this paper is to assess the commercialization feasibility of vegetable oils as industrial fuels and lubricants. The paper also discusses what should be the suitable mix of Italian Government agricultural, environmental and fiscal strategies to support and encourage the production and use of industrial vegetable fuel oils and lubricants. It points out the main advantages of bio-fuel oils - they are much less polluting than conventional fossil fuel oils and can be produced domestically, thus reducing national dependency on foreign energy imports and increasing employment opportunities. The major obstacle to their development is identified as being the creation of suitable pricing and fiscal policies in harmony with traditional energy markets

To what extent can vegetation change and plant stress be surveyed by remote sensing?

Energy Technology Data Exchange (ETDEWEB)

Toemmervik, Hans

1998-12-31

Air pollution from the nickel processing industry in the Kola region of Russia accounts for a large part of the environmental problems in the north-eastern parts of Norway and Finland. The objectives of this thesis were to examine if vegetation damage and plant stress can be surveyed by remote sensing and to assess the use of chlorophyll fluorescence measurements to detect plant stress in the field. The study was carried out in the border area between Norway and Russia. Two spaceborne and one airborne sensors were used. Changes in vegetation cover could be monitored with a degree of accuracy varying from 75 to 83%. A hybrid classification method monitored changes in both lichen dominated vegetation and in vegetation cover types dominated by dwarf shrubs and green plants, which were significantly associated with the differences in SO{sub 2} emission during the period from 1973 to 1994. Vegetation indices, change detection maps and prediction maps provided information on biomass and coverage of green vegetation. This was associated with the differences in the SO{sub 2} emissions during the same period. The vegetation and land cover types with the greatest stress and damage had the largest modelled SO{sub 2} concentration levels in the ground air layer while the vegetation cover types with the lowest degree of stress had the lowest. Comparison of the airborne casi map with the previously processed Landsat TM map from the same area showed that the casi map separated the complete vegetation cover into more detail than the Landsat TM map. The casi images indicated a red-edge shift for the medium to heavily damaged vegetation cover types. Problems with using airborne remote sensing by casi include variable clouds, lack of synoptic view, and cost. The variation in chlorophyll fluorescence of 11 plant species at 16 sites was most influenced by precipitation, temperature and continentality. 373 refs., 49 figs., 37 tabs.

Eye blinking in an avian species is associated with gaze shifts.

Science.gov (United States)

Yorzinski, Jessica L

2016-08-30

Even when animals are actively monitoring their environment, they lose access to visual information whenever they blink. They can strategically time their blinks to minimize information loss and improve visual functioning but we have little understanding of how this process operates in birds. This study therefore examined blinking in freely-moving peacocks (Pavo cristatus) to determine the relationship between their blinks, gaze shifts, and context. Peacocks wearing a telemetric eye-tracker were exposed to a taxidermy predator (Vulpes vulpes) and their blinks and gaze shifts were recorded. Peacocks blinked during the majority of their gaze shifts, especially when gaze shifts were large, thereby timing their blinks to coincide with periods when visual information is already suppressed. They inhibited their blinks the most when they exhibited high rates of gaze shifts and were thus highly alert. Alternative hypotheses explaining the link between blinks and gaze shifts are discussed.

A phenomenological view of language shift.

Science.gov (United States)

Tsitsipis, Lukas D

2004-01-01

Sociolinguistic studies of language shift have in their majority framed their research object in a horizon of theoretically received variables such as class, ethnicity, locality, attitudes etc. In spite of a limited usefulness of such conceptual variables, and of a recently emerging focus on agency, negotiation, and praxis the best results we obtain have not questioned in a coherent and theoretically sound manner the continuing hegemony of mechanistic-metaphorical models (language death, language suicide). In this paper I propose to examine language shift as a multifaceted phenomenon, joining in this respect work by other linguistic anthropologists researching similar areas. I specifically argue that by replacing vertical concepts such as age and generation, and dichotomous logics such as center and periphery with phenomenologically inspired concepts such as typifications, consociateship, contemporariness, and stream of consciousness we are in a better position to generalize about language shift dynamics. Data for this work is derived primarily from the Albanian speech communities of modern Greece, but also from other communities for comparative purposes.

The suitability of vegetation for erosion control on uranium mill tailings: A regional analysis

International Nuclear Information System (INIS)

Beedlow, P.A.; McShane, M.C.

1984-01-01

Inactive uranium mill tailings (UMTRAP sites) in the West were grouped into three major climatic regions to evaluate the suitability of vegetation for long-term stabilization: the Colorado Plateau, the West Slope of the Rocky Mountains, and the Northern Great Plains. Four general vegetation types were found at western sites: grassland, shrub, salt shrub and woodland. Soil-loss rates, calculated using the Universal Soil Loss Equation, were variable within regions and vegetation types, but trends were apparent. Calculations indicated that vegetation or vegetation plus a layer of surface rock provided adequate stabilization against long-term average soil loss on slopes of less than 10%. However, at each site, detailed analyses of erosion caused by severe storm events, gully formation and channel cutting is necessary for designing protective covers

Environmental controls on multiscale spatial patterns of salt marsh vegetation

DEFF Research Database (Denmark)

Kim, Daehyun; Cairns, David; Bartholdy, Jesper

2010-01-01

In coastal environments, biogeographic patterns are generally influenced by surface elevation and horizontal distance from sea water. However, it is still unclear whether these major topographic factors are significant controls of vegetation patterns across spatial scales at which different physi...

Short-term fluctuations in vegetation and phytoplankton during the Middle Eocene greenhouse climate: a 640-kyr record from the Messel oil shale (Germany)

Science.gov (United States)

Lenz, Olaf K.; Wilde, Volker; Riegel, Walter

2011-11-01

The Palaeogene was the most recent greenhouse period on Earth. Especially for the Late Palaeocene and Early Eocene, several superimposed short-term hyperthermal events have been described, including extremes such as the Palaeocene-Eocene Thermal Maximum. Major faunal and floral turnovers in the marine and terrestrial realms were recorded in association with these events. High-resolution palynological analysis of the early Middle Eocene maar lake sediments at Messel, near Darmstadt, Germany, provides an insight into the dynamics of a climax vegetation during the Middle Eocene greenhouse climate in a time span without significant climatic excursions. Numerical techniques like detrended correspondence analysis and wavelet analysis have been applied to recognize cyclic fluctuations and long-term trends in the vegetation through a time interval of approximately 640 kyr. Based on the numerical zoning of the pollen diagram, three phases in the development of the vegetation may be distinguished. Throughout these phases, the climax vegetation did not change substantially in qualitative composition, but a trend towards noticeably less humid conditions probably in combination with a drop of the water level in the lake may be recognized. A shift in algal population from the freshwater dinoflagellate cyst Messelodinium thielepfeifferae to a dominance of Botryococcus in the uppermost part of the core is interpreted as a response to changes in acidity and nutrient availability within the lake. Time series analyses of pollen assemblages show that variations in the Milankovitch range of eccentricity, obliquity and precession can be distinguished. In addition, fluctuations in the sub-Milankovitch range are indicated. This demonstrates that floral changes during steady depositional conditions in the Middle Eocene of Messel were controlled by orbital forcing.

The Impact of the Rise in Vegetable Prices on Vegetable Producer Behavior–Based on the survey of vegetable producers in Jiayu, Hubei Province

Directory of Open Access Journals (Sweden)

Liu Pan

2015-01-01

Full Text Available In order to study the impact of the rise in prices of vegetables on vegetable producers, and to increase the revenue of vegetable producers, this paper does a survey by anonymous sampling questionnaire. Results shows that: most vegetable growers think that vegetable prices should rise and would continue to rise, and that vegetable prices would increase their revenue, thus in the coming year they would expand the planting scale of vegetable variety whose increase rate is the largest in this year. But because of the increase of logistics costs and production costs, some farmers benefit very little from the rising trend of vegetable prices. Most farmers expect too much in the trend estimation of the prices of vegetables and also lack of planning and forward-looking in production, thus the planting area of single variety is often decided by the market of previous year. According to analysis of the impact of the rise in vegetable prices on vegetable producer behavior, this paper gives the following suggestions to increase revenue of vegetable producers: change the mode of thinking, improve rural information platform, and increase capital investment for vegetable production base.

Could anthropogenic soil erosion have influenced Mediterranean vegetation distribution over the Holocene?

International Nuclear Information System (INIS)

Collins, Pamela M; Kaplan, Jed O; Davis, Basil A S

2010-01-01

The circum-Mediterranean region is characterized by a strongly seasonal climate with rainy winters and intense summertime drought, steep topography, and a multi-millennial history of intensive human land use, all of which make its soils vulnerable to erosion. The historical and stratigraphic record documents severe and long-term soil erosion in several locations in the Mediterranean. A forest-to-scrub transition in Mediterranean vegetation between the mid-Holocene (6,000 yr BP) and the present is evident in the observational palaeorecord. Debate as to the causes of this shift is ongoing. This study seeks to test the sensitivity of large-scale vegetation patterns to changes in soil physical properties such as depth, content of coarse fragments, and organic matter content using the Mediterranean region as a case study. We find that simulated biomes are sensitive to changes in some soil physical properties at some locations, but that threshold values for soil change to affect vegetation are very high. Additional work is required to analyze the role that other soil physical properties, and climate change, played in influencing Holocene land cover change in the Mediterranean, and to improve model representations of relevant processes.

Could anthropogenic soil erosion have influenced Mediterranean vegetation distribution over the Holocene?

Energy Technology Data Exchange (ETDEWEB)

Collins, Pamela M; Kaplan, Jed O; Davis, Basil A S, E-mail: pamela.collins@epfl.c [Soil-Vegetation-Atmosphere Research Group ARVE, Institute of Environmental Science and Technology, Ecole Polytechnique Federal de Lausanne, Station 2, 1015 Lausanne (Switzerland)

2010-03-15

The circum-Mediterranean region is characterized by a strongly seasonal climate with rainy winters and intense summertime drought, steep topography, and a multi-millennial history of intensive human land use, all of which make its soils vulnerable to erosion. The historical and stratigraphic record documents severe and long-term soil erosion in several locations in the Mediterranean. A forest-to-scrub transition in Mediterranean vegetation between the mid-Holocene (6,000 yr BP) and the present is evident in the observational palaeorecord. Debate as to the causes of this shift is ongoing. This study seeks to test the sensitivity of large-scale vegetation patterns to changes in soil physical properties such as depth, content of coarse fragments, and organic matter content using the Mediterranean region as a case study. We find that simulated biomes are sensitive to changes in some soil physical properties at some locations, but that threshold values for soil change to affect vegetation are very high. Additional work is required to analyze the role that other soil physical properties, and climate change, played in influencing Holocene land cover change in the Mediterranean, and to improve model representations of relevant processes.

Effects of extended work shifts on employee fatigue, health satisfaction, work/family balance, and patient safety.

NARCIS (Netherlands)

Estryn-Behar, M.; van der Heijden, Beatrice

2012-01-01

12-hour shifts are quickly spreading in Europe. From our multivariate analysis concerning 25,924 European nurses, including twenty explanatory variables simultaneously, we found that work schedule itself is not a major determinant factor. Nurses aim to choose or accept night shifts or 12-hour shift

Past and future effects of climate change on spatially heterogeneous vegetation activity in China

Science.gov (United States)

Gao, Jiangbo; Jiao, Kewei; Wu, Shaohong; Ma, Danyang; Zhao, Dongsheng; Yin, Yunhe; Dai, Erfu

2017-07-01

Climate change is a major driver of vegetation activity but its complex ecological relationships impede research efforts. In this study, the spatial distribution and dynamic characteristics of climate change effects on vegetation activity in China from the 1980s to the 2010s and from 2021 to 2050 were investigated using a geographically weighted regression (GWR) model. The GWR model was based on combined datasets of satellite vegetation index, climate observation and projection, and future vegetation productivity simulation. Our results revealed that the significantly positive precipitation-vegetation relationship was and will be mostly distributed in North China. However, the regions with temperature-dominated distribution of vegetation activity were and will be mainly located in South China. Due to the varying climate features and vegetation cover, the spatial correlation between vegetation activity and climate change may be altered. There will be different dominant climatic factors for vegetation activity distribution in some regions such as Northwest China, and even opposite correlations in Northeast China. Additionally, the response of vegetation activity to precipitation will move southward in the next three decades. In contrast, although the high warming rate will restrain the vegetation activity, precipitation variability could modify hydrothermal conditions for vegetation activity. This observation is exemplified in the projected future enhancement of vegetation activity in the Tibetan Plateau and weakened vegetation activity in East and Middle China. Furthermore, the vegetation in most parts of North China may adapt to an arid environment, whereas in many southern areas, vegetation will be repressed by water shortage in the future.

Night shift work and incidence of diabetes in the Danish Nurse Cohort

DEFF Research Database (Denmark)

Hansen, Anne B.; Stayner, Leslie; Hansen, Johnni

2016-01-01

OBJECTIVES: Night shift work has been associated with poor sleep, weight gain, metabolic syndrome, which are recognised risk factor for diabetes. However, only a few studies have examined the effect of shift work on diabetes risk. Here, we study the association between shift work and incidence...... for incidence of diabetes until 2013. Nurses reported whether they worked night, evening, rotating or day shifts. We analysed the association between working time and diabetes incidence using a Cox proportional hazards model adjusted for diabetes risk factors, separately with and without adjustment for body...... mass index (BMI) which might be an intermediate variable. RESULTS: Of 19 873 nurses who worked and were diabetes-free at recruitment, 837 (4.4%) developed diabetes during 15 years of follow-up. The majority of nurses (62.4%) worked day shifts, 21.8% rotating shift, 10.1% evening and 5.5% night shifts...

Business opportunities in the Ethiopian fruit and vegetable sector

NARCIS (Netherlands)

Wiersinga, R.C.; Jager, de A.

2009-01-01

The horticultural sector in Ethiopia is growing strongly. Major part of this growth is created by investments in the floriculture sector. Recently more and more in terest from the Dutch private sector is shown in the Ethiopian fruits and vegeta ble sector. Export of fruit and vegetables has been

Vegetation inventory, mapping, and classification report, Fort Bowie National Historic Site

Science.gov (United States)

Studd, Sarah; Fallon, Elizabeth; Crumbacher, Laura; Drake, Sam; Villarreal, Miguel

2013-01-01

A vegetation mapping and characterization effort was conducted at Fort Bowie National Historic Site in 2008-10 by the Sonoran Desert Network office in collaboration with researchers from the Office of Arid lands studies, Remote Sensing Center at the University of Arizona. This vegetation mapping effort was completed under the National Park Service Vegetation Inventory program which aims to complete baseline mapping inventories at over 270 national park units. The vegetation map data was collected to provide park managers with a digital map product that met national standards of spatial and thematic accuracy, while also placing the vegetation into a regional and even national context. Work comprised of three major field phases 1) concurrent field-based classification data collection and mapping (map unit delineation), 2) development of vegetation community types at the National Vegetation Classification alliance or association level and 3) map accuracy assessment. Phase 1 was completed in late 2008 and early 2009. Community type descriptions were drafted to meet the then-current hierarchy (version 1) of the National Vegetation Classification System (NVCS) and these were applied to each of the mapped areas. This classification was developed from both plot level data and censused polygon data (map units) as this project was conducted as a concurrent mapping and classification effort. The third stage of accuracy assessment completed in the fall of 2010 consisted of a complete census of each map unit and was conducted almost entirely by park staff. Following accuracy assessment the map was amended where needed and final products were developed including this report, a digital map and full vegetation descriptions. Fort Bowie National Historic Site covers only 1000 acres yet has a relatively complex landscape, topography and geology. A total of 16 distinct communities were described and mapped at Fort Bowie NHS. These ranged from lush riparian woodlands lining the

Influence of antioxidant rich fresh vegetable juices on starch induced postprandial hyperglycemia in rats.

Science.gov (United States)

Tiwari, Ashok K; Reddy, K Srikanth; Radhakrishnan, Janani; Kumar, D Anand; Zehra, Amtul; Agawane, Sachin B; Madhusudana, K

2011-09-01

This research analyzed the major chemical components and multiple antioxidant activities present in the fresh juice of eight vegetables, and studied their influence on starch induced postprandial glycemia in rats. A SDS-PAGE based protein fingerprint of each vegetable juice was also prepared. The yields of juice, chemical components like total proteins, total polyphenols, total flavonoids, total anthocyanins and free radicals like the ABTS˙(+) cation, DPPH, H(2)O(2), scavenging activities and reducing properties for NBT and FeCl(3) showed wide variations. Vegetable juice from brinjal ranked first in displaying total antioxidant capacity. Pretreatment of rats with vegetable juices moderated starch induced postprandial glycemia. The fresh juice from the vegetables ridge gourd, bottle gourd, ash gourd and chayote significantly mitigated postprandial hyperglycemic excursion. Total polyphenol concentrations present in vegetable juices positively influenced ABTS˙(+) scavenging activity and total antioxidant capacity. However, NBT reducing activity of juices was positively affected by total protein concentration. Contrarily, however, high polyphenol content in vegetable juice was observed to adversely affect the postprandial antihyperglycemic activity of vegetable juices. This is the first report exploring antihyperglycemic activity in these vegetable juices and highlights the possible adverse influence of high polyphenol content on the antihyperglycemic activity of the vegetable juices. This journal is © The Royal Society of Chemistry 2011

Which Food Security Determinants Predict Adequate Vegetable Consumption among Rural Western Australian Children?

Science.gov (United States)

Godrich, Stephanie L; Lo, Johnny; Davies, Christina R; Darby, Jill; Devine, Amanda

2017-01-03

Improving the suboptimal vegetable consumption among the majority of Australian children is imperative in reducing chronic disease risk. The objective of this research was to determine whether there was a relationship between food security determinants (FSD) (i.e., food availability, access, and utilisation dimensions) and adequate vegetable consumption among children living in regional and remote Western Australia (WA). Caregiver-child dyads ( n = 256) living in non-metropolitan/rural WA completed cross-sectional surveys that included questions on FSD, demographics and usual vegetable intake. A total of 187 dyads were included in analyses, which included descriptive and logistic regression analyses via IBM SPSS (version 23). A total of 13.4% of children in this sample had adequate vegetable intake. FSD that met inclusion criteria ( p ≤ 0.20) for multivariable regression analyses included price; promotion; quality; location of food outlets; variety of vegetable types; financial resources; and transport to outlets. After adjustment for potential demographic confounders, the FSD that predicted adequate vegetable consumption were, variety of vegetable types consumed ( p = 0.007), promotion ( p = 0.017), location of food outlets ( p = 0.027), and price ( p = 0.043). Food retail outlets should ensure that adequate varieties of vegetable types (i.e., fresh, frozen, tinned) are available, vegetable messages should be promoted through food retail outlets and in community settings, towns should include a range of vegetable purchasing options, increase their reliance on a local food supply and increase transport options to enable affordable vegetable purchasing.

Which Food Security Determinants Predict Adequate Vegetable Consumption among Rural Western Australian Children?

Directory of Open Access Journals (Sweden)

Stephanie L. Godrich

2017-01-01

Full Text Available Improving the suboptimal vegetable consumption among the majority of Australian children is imperative in reducing chronic disease risk. The objective of this research was to determine whether there was a relationship between food security determinants (FSD (i.e., food availability, access, and utilisation dimensions and adequate vegetable consumption among children living in regional and remote Western Australia (WA. Caregiver-child dyads (n = 256 living in non-metropolitan/rural WA completed cross-sectional surveys that included questions on FSD, demographics and usual vegetable intake. A total of 187 dyads were included in analyses, which included descriptive and logistic regression analyses via IBM SPSS (version 23. A total of 13.4% of children in this sample had adequate vegetable intake. FSD that met inclusion criteria (p ≤ 0.20 for multivariable regression analyses included price; promotion; quality; location of food outlets; variety of vegetable types; financial resources; and transport to outlets. After adjustment for potential demographic confounders, the FSD that predicted adequate vegetable consumption were, variety of vegetable types consumed (p = 0.007, promotion (p = 0.017, location of food outlets (p = 0.027, and price (p = 0.043. Food retail outlets should ensure that adequate varieties of vegetable types (i.e., fresh, frozen, tinned are available, vegetable messages should be promoted through food retail outlets and in community settings, towns should include a range of vegetable purchasing options, increase their reliance on a local food supply and increase transport options to enable affordable vegetable purchasing.

OPTIMIZATION OF VEGETABLE WASTES FOR LACTIC ACID PRODUCTION: A LABORATORY SCALE APPROACH

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Sailaja Daharbha

2015-04-01

Full Text Available Vegetables wastes are organic materials which are not utilized as vegetables and are discarded at all stages of production, processing and marketing. These wastes form a major part of municipal solid wastes and are cause of foul smell and growth of microorganisms due to their high organic contents. The vegetable wastes can be utilized in many different ways to produces different products. We have shown that they can be utilized for production of lactic acid using anaerobic digestion. The 2nd day was the optimum day for recovery of lactic acid while 1:1 ratio of slurry and water was found to the best ratio for production of lactic acid from vegetable wastes. Effect of salts on lactic acid was also studied and it was found that the production decreased in all the concentrations of salts.

Renewable energy from vegetation; Les energies renouvelables d'origine vegetale

Energy Technology Data Exchange (ETDEWEB)

Sales, C. [Centre francais de cooperation international en recherche agronomique pour le developpement (France)

2009-07-15

Currently, vegetation accounts for 3 major types of energy sources, notably woody biomass, starches and vegetable oils. Bio-ethanol and biodiesel is produced from the fermentation of starches, such as sugar cane, beet sugar, sorghum, corn and potatoes. Biofuels can be produced from palm tree oil, coconut oil , soya oil, sunflower oil or any type of vegetable based oil. This article discussed energy efficiency issues and the environmental impact of developing these energies. In general, the lower energy efficiency of the starches can be attributed to the enzymes responsible for the catalysis. The article also reviewed the thermochemistry and energy efficiency regarding second generation fuels. It also discussed the burning of biomass, including woody biomass, forest waste and agricultural waste. 1 ref., 2 figs.

Household Income and Vegetable Consumption among White, Chinese, Korean and Vietnamese Americans

OpenAIRE

Thanh V Tran; Rita Vatcher; Hae Nim Lee; Phu Tai Phan; Thuc-Nhi Nguyen

2013-01-01

Objectives; This study aims to examine racial/ethnic differences in vegetable consumption between White and three major groups of Asian Americans. We hypothesize that racial/ethnic differences in frequency of vegetable consumption is significantly related to respondents¡¯ household income. Methods; We used the 2009 California Health Survey Interview (CHIS) data set that has a total sample of 47,167 respondents aged 18 and over. The selected sample used in this study consisted of four racial a...

Produce from Africa?s Gardens: Potential for Leafy Vegetable and Fruit Fermentations

OpenAIRE

Oguntoyinbo, Folarin A.; Fusco, Vincenzina; Cho, Gyu-Sung; Kabisch, Jan; Neve, Horst; Bockelmann, Wilhelm; Huch, Melanie; Frommherz, Lara; Trierweiler, Bernhard; Becker, Biserka; Benomar, Nabil; G?lvez, Antonio; Abriouel, Hikmate; Holzapfel, Wilhelm H.; Franz, Charles M. A. P.

2016-01-01

A rich variety of indigenous fruits and vegetables grow in Africa, which contribute to the nutrition and health of Africa’s populations. Fruits and vegetables have high moisture and are thus inherently prone to accelerated spoilage. Food fermentation still plays a major role in combating food spoilage and foodborne diseases that are prevalent in many of Africa’s resource disadvantaged regions. Lactic acid fermentation is probably the oldest and best-accepted food processing method among the A...

Observational Quantification of Climatic and Human Influences on Vegetation Greening in China

Directory of Open Access Journals (Sweden)

Wenjian Hua

2017-04-01

Full Text Available This study attempts to quantify the relative contributions of vegetation greening in China due to climatic and human influences from multiple observational datasets. Satellite measured vegetation greenness, Normalized Difference Vegetation Index (NDVI, and relevant climate, land cover, and socioeconomic data since 1982 are analyzed using a multiple linear regression (MLR method. A statistically significant positive trend of average growing-season (April–October NDVI is found over more than 34% of the vegetated areas, mainly in North China, while significant decreases in NDVI are only seen in less than 5% of the areas. The relationships between vegetation and climate (temperature, precipitation, and radiation vary by geographical location and vegetation type. We estimate the NDVI changes in association with the non-climatic effects by removing the climatic effects from the original NDVI time series using the MLR analysis. Our results indicate that land use change is the dominant factor driving the long-term changes in vegetation greenness. The significant greening in North China is due to the increase in crops, grasslands, and forests. The socioeconomic datasets provide consistent and supportive results for the non-climatic effects at the provincial level that afforestation and reduced fire events generally have a major contribution. This study provides a basis for quantifying the non-climatic effects due to possible human influences on the vegetation greening in China.

Advances in remote sensing of vegetation function and traits

KAUST Repository

Houborg, Rasmus

2015-07-09

Remote sensing of vegetation function and traits has advanced significantly over the past half-century in the capacity to retrieve useful plant biochemical, physiological and structural quantities across a range of spatial and temporal scales. However, the translation of remote sensing signals into meaningful descriptors of vegetation function and traits is still associated with large uncertainties due to complex interactions between leaf, canopy, and atmospheric mediums, and significant challenges in the treatment of confounding factors in spectrum-trait relations. This editorial provides (1) a background on major advances in the remote sensing of vegetation, (2) a detailed timeline and description of relevant historical and planned satellite missions, and (3) an outline of remaining challenges, upcoming opportunities and key research objectives to be tackled. The introduction sets the stage for thirteen Special Issue papers here that focus on novel approaches for exploiting current and future advancements in remote sensor technologies. The described enhancements in spectral, spatial and temporal resolution and radiometric performance provide exciting opportunities to significantly advance the ability to accurately monitor and model the state and function of vegetation canopies at multiple scales on a timely basis.

Analyzing Vegetation Change in an Elephant-Impacted Landscape Using the Moving Standard Deviation Index

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Timothy J. Fullman

2014-01-01

Full Text Available Northern Botswana is influenced by various socio-ecological drivers of landscape change. The African elephant (Loxodonta africana is one of the leading sources of landscape shifts in this region. Developing the ability to assess elephant impacts on savanna vegetation is important to promote effective management strategies. The Moving Standard Deviation Index (MSDI applies a standard deviation calculation to remote sensing imagery to assess degradation of vegetation. Used previously for assessing impacts of livestock on rangelands, we evaluate the ability of the MSDI to detect elephant-modified vegetation along the Chobe riverfront in Botswana, a heavily elephant-impacted landscape. At broad scales, MSDI values are positively related to elephant utilization. At finer scales, using data from 257 sites along the riverfront, MSDI values show a consistent negative relationship with intensity of elephant utilization. We suggest that these differences are due to varying effects of elephants across scales. Elephant utilization of vegetation may increase heterogeneity across the landscape, but decrease it within heavily used patches, resulting in the observed MSDI pattern of divergent trends at different scales. While significant, the low explanatory power of the relationship between the MSDI and elephant utilization suggests the MSDI may have limited use for regional monitoring of elephant impacts.

Analysis of Decadal Vegetation Dynamics Using Multi-Scale Satellite Images

Science.gov (United States)

Chiang, Y.; Chen, K.

2013-12-01

This study aims at quantifying vegetation fractional cover (VFC) by incorporating multi-resolution satellite images, including Formosat-2(RSI), SPOT(HRV/HRG), Landsat (MSS/TM) and Terra/Aqua(MODIS), to investigate long-term and seasonal vegetation dynamics in Taiwan. We used 40-year NDVI records for derivation of VFC, with field campaigns routinely conducted to calibrate the critical NDVI threshold. Given different sensor capabilities in terms of their spatial and spectral properties, translation and infusion of NDVIs was used to assure NDVI coherence and to determine the fraction of vegetation cover at different spatio-temporal scales. Based on the proposed method, a bimodal sequence of intra-annual VFC which corresponds to the dual-cropping agriculture pattern was observed. Compared to seasonal VFC variation (78~90%), decadal VFC reveals moderate oscillations (81~86%), which were strongly linked with landuse changes and several major disturbances. This time-series mapping of VFC can be used to examine vegetation dynamics and its response associated with short-term and long-term anthropogenic/natural events.

Night sleep in patients with vegetative state.

Science.gov (United States)

Pavlov, Yuri G; Gais, Steffen; Müller, Friedemann; Schönauer, Monika; Schäpers, Barbara; Born, Jan; Kotchoubey, Boris

2017-10-01

Polysomnographic recording of night sleep was carried out in 15 patients with the diagnosis vegetative state (syn. unresponsive wakefulness syndrome). Sleep scoring was performed by three raters, and confirmed by means of a spectral power analysis of the electroencephalogram, electrooculogram and electromyogram. All patients but one exhibited at least some signs of sleep. In particular, sleep stage N1 was found in 13 patients, N2 in 14 patients, N3 in nine patients, and rapid eye movement sleep in 10 patients. Three patients exhibited all phenomena characteristic for normal sleep, including spindles and rapid eye movements. However, in all but one patient, sleep patterns were severely disturbed as compared with normative data. All patients had frequent and long periods of wakefulness during the night. In some apparent rapid eye movement sleep episodes, no eye movements were recorded. Sleep spindles were detected in five patients only, and their density was very low. We conclude that the majority of vegetative state patients retain some important circadian changes. Further studies are necessary to disentangle multiple factors potentially affecting sleep pattern of vegetative state patients. © 2017 European Sleep Research Society.

MACROPHYTE RICHNESS AND AQUATIC VEGETATION COMPLEXITY OF THE LAKE IDRO (NORTHERN ITALY

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R. Bolpagni

2013-04-01

Full Text Available A detailed survey was performed to examine the floristic richness and the structural complexity, spatial patterns and conservation value of aquatic plant communities within the littorals of Lake Idro (northern Italy. During the summers of 2010-2011 we proceeded to characterize aquatic macrophyte meadows applying standardized procedures using transects (44 and plots (49 arrayed perpendicular to the shoreline and randomly positioned within the vegetated belt, respectively. Lake Idro is characterized by rather high floristic richness (20 macrophytes but low levels of vegetation structural complexity (8 vegetation units. Nevertheless, a clear zonation of the littoral vegetation was identified with two main macro-layers: a deeper layer (between 6-10 m of depth dominated by Chara globularis and an upper one (from 6 m of depth to water-air atmosphere mainly colonized by alien elodeids (mainly Elodea nuttallii and Lagarosiphon major. For the first time a complete floristic-vegetation analysis of the Lake Idro was presented. Our data confirm the poor ecological status of the basin, even though the lacustrine vegetation can be considered of conservation concern. Further investigations are needed to improve present evaluations, especially with respect to the impact of eutrophication on macrophytic communities.

Pathogenic specifics of development of vegetative dysfunction in adolescents in relation to their morphological status

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O. Skyba

2017-02-01

Full Text Available Exploring the mechanisms of vegetative regulation in children and adolescents of different somatotypes has a prognostic value in regard to the character of adaptive reactions of the organism, as it facilitates the identification of the risk factors of pathological processes and states of vegetative systems, which may cause chronic illness in adulthood. The author defines the pathogenic specifics of development of vegetative dysfunction in adolescents in relation to their morphological status. Cardiointervalography and anthropometric, mathematical and statistical methods of research were used. Based on the results of cardiointervalography, the structure of initial vegetative tonus was established, which was characterized by prevalence of eutonia (38.4 ± 4.9%. The specific weight with background eutonia of adolescent boys and girls tended to be higher among the representatives of the thoracic and muscular somatotypes, compared to adolescents of the alimentive and osseous somatotypes (Р < 0.001–0.05. The established specifics indicate that thoracic and muscular somatotypes ensure optimal adaptation of organisms to the environment. Sympathicotonia was measured among the majority of boys of extreme constitutional variants (alimentive and osseous somatotypes (36.3% and 30.0% respectively, which demonstrates the activation of adaptive mechanisms in the abovementioned category of examined adolescents, while among girls this phenomenon was evident among the representatives of the osseous and thoracic somatotypes (38.5% and 30.8% respectively. We found that the majority of examined adolescents (53.4% had a normal vegetative reactivity. Gender differences in the structure of vegetative reactivity of adolescents could well be explained by the higher number of girls of asympaticotonic type (19.2% compared to boys (7.3%, Р < 0.05. Furthermore, we found that hypersympathicotonic and asympathicotonic types of vegetative reactivity were characteristic of

Host Plant Physiology and Mycorrhizal Functioning Shift across a Glacial through Future [CO2] Gradient1[OPEN

Science.gov (United States)

Mullinix, George W.R.; Ward, Joy K.

2016-01-01

Rising atmospheric carbon dioxide concentration ([CO2]) may modulate the functioning of mycorrhizal associations by altering the relative degree of nutrient and carbohydrate limitations in plants. To test this, we grew Taraxacum ceratophorum and Taraxacum officinale (native and exotic dandelions) with and without mycorrhizal fungi across a broad [CO2] gradient (180–1,000 µL L−1). Differential plant growth rates and vegetative plasticity were hypothesized to drive species-specific responses to [CO2] and arbuscular mycorrhizal fungi. To evaluate [CO2] effects on mycorrhizal functioning, we calculated response ratios based on the relative biomass of mycorrhizal (MBio) and nonmycorrhizal (NMBio) plants (RBio = [MBio − NMBio]/NMBio). We then assessed linkages between RBio and host physiology, fungal growth, and biomass allocation using structural equation modeling. For T. officinale, RBio increased with rising [CO2], shifting from negative to positive values at 700 µL L−1. [CO2] and mycorrhizal effects on photosynthesis and leaf growth rates drove shifts in RBio in this species. For T. ceratophorum, RBio increased from 180 to 390 µL L−1 and further increases in [CO2] caused RBio to shift from positive to negative values. [CO2] and fungal effects on plant growth and carbon sink strength were correlated with shifts in RBio in this species. Overall, we show that rising [CO2] significantly altered the functioning of mycorrhizal associations. These symbioses became more beneficial with rising [CO2], but nonlinear effects may limit plant responses to mycorrhizal fungi under future [CO2]. The magnitude and mechanisms driving mycorrhizal-CO2 responses reflected species-specific differences in growth rate and vegetative plasticity, indicating that these traits may provide a framework for predicting mycorrhizal responses to global change. PMID:27573369

Comparing the response of birds and butterflies to vegetation-based mountain ecotones using boundary detection approaches.

Science.gov (United States)

Kent, Rafi; Levanoni, Oded; Banker, Eran; Pe'er, Guy; Kark, Salit

2013-01-01

Mountains provide an opportunity to examine changes in biodiversity across environmental gradients and areas of transition (ecotones). Mountain ecotones separate vegetation belts. Here, we aimed to examine whether transition areas for birds and butterflies spatially correspond with ecotones between three previously described altitudinal vegetation belts on Mt. Hermon, northern Israel. These include the Mediterranean Maquis, xero-montane open forest and Tragacanthic mountain steppe vegetation belts. We sampled the abundance of bird and butterfly species in 34 sampling locations along an elevational gradient between 500 and 2200 m. We applied wombling, a boundary-detection technique, which detects rapid changes in a continuous variable, in order to locate the transition areas for bird and butterfly communities and compare the location of these areas with the location of vegetation belts as described in earlier studies of Mt. Hermon. We found some correspondence between the areas of transition of both bird and butterfly communities and the ecotones between vegetation belts. For birds and butterflies, important transitions occurred at the lower vegetation ecotone between Mediterranean maquis and the xero-montane open forest vegetation belts, and between the xero-montane open forest and the mountain steppe Tragacanthic belts. While patterns of species turnover with elevation were similar for birds and butterflies, the change in species richness and diversity with elevation differed substantially between the two taxa. Birds and butterflies responded quite similarly to the elevational gradient and to the shift between vegetation belts in terms of species turnover rates. While the mechanisms generating these patterns may differ, the resulting areas of peak turnover in species show correspondence among three different taxa (plants, birds and butterflies).

Novice Nurses’ Perception of Working Night Shifts: A Qualitative Study

Directory of Open Access Journals (Sweden)

Mohsen Faseleh Jahromi

2013-08-01

Full Text Available Introduction: Nursing is always accompanied by shift working and nurses in Iran have to work night shifts in some stages of their professional life. Therefore, the present study aimed to describe the novice nurses’ perception of working night shifts. Methods: The present qualitative study was conducted on 20 novice nurses working in two university hospitals of Jahrom, Iran. The study data were collected through focus group interviews. All the interviews were recorded, transcribed, and analyzed using constant comparative analysis and qualitative content analysis. Results: The study findings revealed five major themes of value system, physical and psychological problems, social relationships, organizational problems, and appropriate opportunity. Conclusion: The study presented a deep understanding of the novice nurses’ perception of working night shifts, which can be used by the managers as a basis for organizing health and treatment systems.

Monitoring leafy vegetables through packaging films with

OpenAIRE

Diezma Iglesias, Belen; Lara, M.A.; Molina, Marta; Lleó García, Lourdes; Ruiz-Altisent, Margarita; Artés Hernández, Francisco; Roger, Jean-Michel

2012-01-01

Fresh-cut or minimally processed fruit and vegetables have been physically modified from its original form (by peeling, trimming, washing and cutting) to obtain a 100% edible product that is subsequently packaged (usually under modified atmosphere packaging –MAP) and kept in refrigerated storage. In fresh-cut products, physiological activity and microbiological spoilage, determine their deterioration and shelf-life. The major preservation techniques applied to delay spoilage are chilling s...

The present flora and vegetation of the moraines of the Klutlan Glacier, Yukon Territory, Canada: A study in plant succession*1

Science.gov (United States)

Birks, H. J. B.

1980-07-01

The flora and vegetation of six ice-cored moraines of the Klutlan Glacier were analyzed in 65 plots by European plant-sociological techniques. The age of each plot was estimated from annual growth rings of shrubs or trees in the plots. Nine major vegetation types are distinguished: Crepis nana, Dryas drummondii, Hedysarum mackenzii, Hedysarum-Salix, Salix-Shepherdia canadensis, Picea-Salix, Picea-Arctostaphylos, Picea-Ledum, and Picea-Rhytidium. These contain plants aged 2-6, 9-23, 10-20, 24-30, 32-58, 58-80, 96-178, 177-240, and >163- >339 yr, respectively. Six other vegetation types are described from windthrow areas, drainage channels, volcanic tephra slopes, lake margins, fens, and drained lakes. The major vegetation types reflect a vegetational succession related to moraine age and stability, with the Crepis nana type as the pioneer vegetation developing through the other vegetation types to the Picea-Rhytidium type on the oldest moraines. Changes in species diversity and soil development, particularly humus accumulation, parallel the vegetational succession. This succession differs from patterns of revegetation of deglaciated landscapes in Alaska and British Columbia today and in Minnesota in late-Wisconsin times because of differences in climate, plant migration, and local ecology.

Using a Dynamic Global Vegetation Model to Simulate the Response of Vegetation to Warming at the Paleocene-Eocene Boundary

Science.gov (United States)

Shellito, C. J.; Sloan, L. C.

2004-12-01

A major turnover in benthic marine and terrestrial fauna marks the Initial Eocene Thermal Maximum (IETM) (~55Ma), a period of ~150 ky in which there was a rapid rise in deep sea and high latitude sea surface temperatures by 5-8C. Curiously, no major responses to this warming in the terrestrial floral record have been detected to date. Here, we present results from experiments examining the response of the global distribution of vegetation to changes in climate at the IETM using the NCAR Land Surface Model (LSM1.2) integrated with a dynamic global vegetation model (DGVM). DGVMs allow vegetation to respond to and interact with climate, and thus, provide a unique new method for addressing questions regarding feedbacks between the ecosystem and climate in Earth's past. However, there are a number of drawbacks to using these models that can affect interpretation of results. More specifically, these drawbacks involve uncertainties in the application of modern plant functional types to paleo-flora simulations, inaccuracies in the model climatology used to drive the DGVM, and lack of available detail regarding paleo-geography and paleo-soil type for use in model boundary conditions. For a better understanding of these drawbacks, we present results from a series of tests in the NCAR LSM-DGVM which examine (1) the effect of removing C4 grasses from the available plant functional types in the model; (2) model sensitivity to a change in soil texture; and (3), model sensitivity to a change in the value of pCO2 used in the photosynthetic rate equations. We consider our DGVM results for the IETM in light of output from these sensitivity experiments.

Variation in vegetable production among urban farmers in Ilorin, Kwara state, Nigeria

Directory of Open Access Journals (Sweden)

Yusuf, O.R.

2012-12-01

Full Text Available Urban agriculture in Nigerian cities has contributed immensely to provision of fresh vegetables and the overall food security in the urban space. Though this vegetable production takes place throughout the year, resource utilization that contributes to productivity among the various groups of urban cultivators is improperly understood. This paper addresses this issue in Ilorin, focusing on seventy farmers drawn from the two major groups of cultivators; Fadama and Okiti. Data were gathered through the use of focus group discussion (FGD, non participant observation, and questionnaire survey. Tabulation, percentages and trend description were employed in data analysis. Multiple Regression Analysis isolated utilization of pump machine, harvest from vegetable plots, utilization of modern input and type of labour used as the determinants of efficiency with a total percentage contribution of 89.6 to land-use, the major resource. Among the major findings is that the operational scale of Fadama cultivators is larger with a corresponding increase in profit compared to Okiti cultivators. It is also discovered that although the two systems are faced with similar constraints of environmental and inaccessibility to input problems, there exist some fundamental differences based on scale and production efficiency. Some solutions proffered to the identified problem include the recognition and integration of urban farmers into urban land use structure so that they can form cooperatives through which they can access productive inputs.

Stochastic radiative transfer model for mixture of discontinuous vegetation canopies

International Nuclear Information System (INIS)

Shabanov, Nikolay V.; Huang, D.; Knjazikhin, Y.; Dickinson, R.E.; Myneni, Ranga B.

2007-01-01

Modeling of the radiation regime of a mixture of vegetation species is a fundamental problem of the Earth's land remote sensing and climate applications. The major existing approaches, including the linear mixture model and the turbid medium (TM) mixture radiative transfer model, provide only an approximate solution to this problem. In this study, we developed the stochastic mixture radiative transfer (SMRT) model, a mathematically exact tool to evaluate radiation regime in a natural canopy with spatially varying optical properties, that is, canopy, which exhibits a structured mixture of vegetation species and gaps. The model solves for the radiation quantities, direct input to the remote sensing/climate applications: mean radiation fluxes over whole mixture and over individual species. The canopy structure is parameterized in the SMRT model in terms of two stochastic moments: the probability of finding species and the conditional pair-correlation of species. The second moment is responsible for the 3D radiation effects, namely, radiation streaming through gaps without interaction with vegetation and variation of the radiation fluxes between different species. We performed analytical and numerical analysis of the radiation effects, simulated with the SMRT model for the three cases of canopy structure: (a) non-ordered mixture of species and gaps (TM); (b) ordered mixture of species without gaps; and (c) ordered mixture of species with gaps. The analysis indicates that the variation of radiation fluxes between different species is proportional to the variation of species optical properties (leaf albedo, density of foliage, etc.) Gaps introduce significant disturbance to the radiation regime in the canopy as their optical properties constitute major contrast to those of any vegetation species. The SMRT model resolves deficiencies of the major existing mixture models: ignorance of species radiation coupling via multiple scattering of photons (the linear mixture model

Effects of Accumulating Work Shifts on Performance-Based Fatigue Using Multiple Strength Measurements in Day and Night Shift Nurses and Aides.

Science.gov (United States)

Thompson, Brennan J; Stock, Matt S; Banuelas, Victoria K

2017-05-01

Objective This study aimed to examine the effects of accumulating nursing work on maximal and rapid strength characteristics in female nurses and compare these effects in day versus night shift workers. Background Nurses exhibit among the highest nonfatal injury rates of all occupations, which may be a consequence of long, cumulative work shift schedules. Fatigue may accumulate across multiple shifts and lead to performance impairments, which in turn may be linked to injury risks. Method Thirty-seven nurses and aides performed isometric strength-based performance testing of three muscle groups, including the knee extensors, knee flexors, and wrist flexors (hand grip), as well as countermovement jumps, at baseline and following exposure to three 12-hour work shifts in a four-day period. Variables included peak torque (PT) and rate of torque development (RTD) from isometric strength testing and jump height and power output. Results The rigorous work period resulted in significant decreases (-7.2% to -19.2%) in a large majority (8/9) of the isometric strength-based measurements. No differences were noted for the day versus night shift workers except for the RTD at 200 millisecond variable, for which the night shift had greater work-induced decreases than the day shift workers. No changes were observed for jump height or power output. Conclusions A compressed nursing work schedule resulted in decreases in strength-based performance abilities, being indicative of performance fatigue. Application Compressed work schedules involving long shifts lead to functional declines in nurse performance capacities that may pose risks for both the nurse and patient quality of care. Fatigue management plans are needed to monitor and regulate increased levels of fatigue.

Albedo and vegetation demand-side management options for warm climates

International Nuclear Information System (INIS)

Hall, Darwin C.

1997-01-01

For electric utilities, demand-side management (DSM) can reduce electric load and shift load from peak to off-peak periods. In general, the investor in DSM collects the reward with lower electric bills, excepting a positive externality because of reduced tropospheric and stratospheric air pollution from fossil fuel power plants. In warm climates, DSM options include increasing albedo and vegetation, respectively, by painting surfaces white and planting trees; these DSM options are distinguished from all other DSM options because of ecosystem effects. Ambient temperature falls, mitigating the urban 'heat island', which reduces electric load and ozone formation. The investor in albedo and vegetation DSM options does not collect all of the reward from lower electric bills, since the lower ambient temperature provides savings to all customers who use electricity for air conditioning and refrigeration. Similar to other DSM options, air pollution is also reduced as a result of lower power plant emissions. Complex airshed models and electric utility system dispatch models are applied in this paper to account for some of these ecosystem effects. Unaccounted ecosystem effects remain, stymieing cost effectiveness analysis

Disentangling Modern Fire-Climate-Vegetation Relationships across the Boreal Forest Biome

Science.gov (United States)

Young, A. M.; Boschetti, L.; Duffy, P.; Hu, F.; Higuera, P.

2015-12-01

Fire regimes differ between Eurasian and North American boreal forests, due in part to differences in climate and the dominant forest types. While North American boreal forests are dominated by stand-replacing fires, much of the Eurasian boreal forest is characterized by lower intensity surface fires. These different fire regimes have important consequences for continental-scale biogeochemical cycling and surface-energy fluxes1. Here, we use generalized linear models (GLM) and boosted regression trees (BRT) to explore the relative importance of vegetation, annual climatic factors, and their interactions in determining annual fire occurrence across Eurasian and North American boreal forests. We use remotely sensed burned area (MCD64A1), land cover (MCD12Q1), and observed climate data (CRU) from 2002-2012 at 0.25° spatial resolution to quantify these relationships at annual temporal scales and continental spatial scales. The spatial distribution of boreal fire occurrence was well explained with climate and vegetation variables, with similarities and differences in fire-climate-vegetation relationships between Eurasia and North America. For example, while GLMs indicate vegetation is a significant factor determining fire occurrence in both continents, the effect of climate differed. Spring temperature and precipitation are significant factors explaining fire occurrence in Eurasia, but no climate variables were significant for explaining fire occurrence in North America. BRTs complement this analysis, highlighting climatic thresholds to fire occurrence in both continents. The nature of these thresholds can vary among vegetation types, even within each continent, further implying regional sensitivity to climate-induced shifts in wildfire activity. To build on these results and better understand regional sensitivity of northern-high latitude fire regimes, future work will explore these relationships in forest-tundra and arctic tundra ecosystems, and apply historical

Site vegetation report: Terrestrial vegetation survey (1993--1995) for the Rocky Flats Environmental Technology Site

International Nuclear Information System (INIS)

1997-06-01

The Ecological Monitoring Program (EcMP) was designed to investigate the long-term ecological trends in terrestrial and aquatic ecosystems at the US Department of energy's (DOE's) Rocky Flats Environmental Technology Site (Site) (DOE 1993). Field sampling was conducted during 1993, 1994, and 1995, until the program was terminated in late 1995. This report presents the terrestrial vegetation data that were gathered by the EcMP. The site is located on the Colorado Piedmont, east of the Front Range, between Boulder and Golden, approximately 25 km (16 miles) northwest of Denver. The topography and proximity of the Site to the mountain front result in an interesting mixture of prairie and mountain plant species. The Site is one of the few large, relatively undisturbed areas of its kind that remains along the Colorado Piedmont. Until 1989, the primary mission of the Site was the production of nuclear weapons components (DOE 1993). After production ceased, Site personnel shifted their focus to cleanup and closure

Site vegetation report: Terrestrial vegetation survey (1993--1995) for the Rocky Flats Environmental Technology Site

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-06-01

The Ecological Monitoring Program (EcMP) was designed to investigate the long-term ecological trends in terrestrial and aquatic ecosystems at the US Department of energy`s (DOE`s) Rocky Flats Environmental Technology Site (Site) (DOE 1993). Field sampling was conducted during 1993, 1994, and 1995, until the program was terminated in late 1995. This report presents the terrestrial vegetation data that were gathered by the EcMP. The site is located on the Colorado Piedmont, east of the Front Range, between Boulder and Golden, approximately 25 km (16 miles) northwest of Denver. The topography and proximity of the Site to the mountain front result in an interesting mixture of prairie and mountain plant species. The Site is one of the few large, relatively undisturbed areas of its kind that remains along the Colorado Piedmont. Until 1989, the primary mission of the Site was the production of nuclear weapons components (DOE 1993). After production ceased, Site personnel shifted their focus to cleanup and closure.

European Vegetation Archive (EVA): an integrated database of European vegetation plots

DEFF Research Database (Denmark)

Chytrý, M; Hennekens, S M; Jiménez-Alfaro, B

2015-01-01

vegetation- plot databases on a single software platform. Data storage in EVA does not affect on-going independent development of the contributing databases, which remain the property of the data contributors. EVA uses a prototype of the database management software TURBOVEG 3 developed for joint management......The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and regional...... data source for large-scale analyses of European vegetation diversity both for fundamental research and nature conservation applications. Updated information on EVA is available online at http://euroveg.org/eva-database....

The role of wild fruits and vegetables in delivering a balanced and healthy diet.

Science.gov (United States)

Bvenura, Callistus; Sivakumar, Dharini

2017-09-01

Without a doubt, fruits and vegetables are important components of a balanced and healthy diet. However, their consumption is very low in the world, with the lowest figures being reported in sub-Saharan Africa. The low consumption of fruits and vegetables means unbalanced and unhealthy diets, which has been linked to various diseases and conditions associated with increased mortality rates in worst cases. Poverty is the major contributor to the low consumption of fruits and vegetables in the majority of cases. However, the world, including sub-Saharan Africa, is endowed with numerous wild fruit and vegetable species which can be exploited and incorporated into the diets and help solve some nutrition related concerns. Therefore, in this review, we explore literature on wild fruits and vegetables with a special emphasis on some of the poorest regions of the world and where the lowest consumption figures are reported; their nutritional compositions; the status of their consumption and their role in the diet with a view to uncover their possible role in delivering a healthy and balanced diet as well as helping lower food and nutrition insecurity. A total of 396 articles were downloaded and analysed but only 213 were considered for this review. The results of the search indicate that wild fruits and vegetables are nutritionally rich and high in phytochemicals, especially antioxidants and therefore can possibly play a significant and positive role in delivering a healthy and balanced diet. However, the major challenge is the acceptability, accessibility as well as a lack of interest in wild fruits and vegetables and sheer neglect. People need to be educated using various forms of media on the nutritional and health benefits of these wild food plants with a view to bring them from the forest to the plate. Researchers need to channel more efforts towards domesticating them for ease of access, among other reasons. Governments need to incentivise the subsistence or

Vegetation composition and structure significantly influence green roof performance

Energy Technology Data Exchange (ETDEWEB)

Dunnett, N.; Nagase, A.; Booth, R.; Grime, P. [Sheffield Univ., Sheffield (United Kingdom). Dept. of Landscape Architecture

2005-07-01

The majority of published literature on green roofs contains little specific information on the contribution of plants to the various functions and properties of green roofs. This paper reviewed previously published material in an attempt to shed light on the role of vegetation composition in green roof systems, with specific reference to hydrology and biodiversity support. Two ongoing experiments at the University of Sheffield were then considered: (1) a comparison of quality and quantity of runoff from different types of vegetation; and (2) a comparison of flowering seasons and biodiversity support of different vegetation. Results of the studies showed that there was no general pattern of variation in runoff that could be related to vegetation complexity or taxonomic composition of the communities. During the winter months, high precipitation quickly saturated the soil and percolate losses were similar for all treatments. In the summer, throughflow losses differed between treatments in relation to the structure of the plant canopy. Differing mechanisms resulted in variations in the volume of percolate that was collected. Lower volumes of percolate were observed in herb-only monocultures of Leontdon hispidus, a species with a high water content. Tap-rooted species were seen to more effectively absorb soil moisture. The biodiversity support study focused on the study of Sedum species and Labiatae species, which suggested that mixed vegetation containing these species had a far greater likelihood of attracting wild bees to support pollination. Results of the studies indicated that green roof vegetation with greater structural and species diversity may provide different benefits than sedum-dominated roots. Further studies are needed to investigate the trade-offs between vegetation types, and green roof functions and performance in order to justify calls for a wider diversity of green roof types. 8 refs., 2 tabs., 1 fig.

The financial feasibility of producing fish and vegetables through aquaponics

NARCIS (Netherlands)

Bosma, Roel H.; Lacambra, Lysette; Landstra, Ynze; Perini, Chiara; Poulie, Joline; Schwaner, Marie J.; Yin, Yi

2017-01-01

Aquaponics, producing fish and vegetables in a closed-loop water system, reduces fertilizer use and water discharge, and is therefore promoted as a sustainable venture. A recent global study found that the majority of 257 surveyed aquaponics farms made losses, but the reasons have been poorly

Vegetation patterns and nutrients in relation to grazing pressure and ...

African Journals Online (AJOL)

A major challenge confronting managers of extensive grazing systems is uneven use of erbaceous forage plants by livestock. The concentration of grazing in preferred areas or around foci points (e.g. water points) eventually results in adverse impacts in soil nutrients, vegetation structure, production and composition.

The human factors of implementing shift work in logging operations.

Science.gov (United States)

Mitchell, D L; Gallagher, T V; Thomas, R E

2008-10-01

A fairly recent development in the forest industry is the use of shift work in logging in the southeastern U.S. Logging company owners are implementing shift work as an opportunity to increase production and potentially reduce the cost of producing each unit of wood, without consideration of the potential impacts on the logging crew. There are many documented physiological and psychological impacts on workers from shift work in a variety of industries, although few address forestry workers in the U.S. Semi-structured interviews were performed to gather information about how logging company owners were implementing shift work in seven southeastern states. Data collected during the interviews included employee turnover, shift hours, shift scheduling, safety considerations, and production impacts. Various work schedules were employed. The majority of the schedules encompassed less than 24 hours per day. Permanent and rotating shift schedules were found. None of the logging company owners used more than two crews in a 24-hour period. Additional safety precautions were implemented as a result of working after dark. No in-woods worker accidents or injuries were reported by any of those interviewed. Results indicate that a variety of work schedules can be successfully implemented in the southeastern logging industry.

Detecting vegetation change using multi-temporal aerial photographs at Cadillac Mountain in Acadia National Park, Maine

Science.gov (United States)

Min Kook Kim; Andrea J. Ednie; John J. Daigle

2007-01-01

Cadillac Mountain, the highest peak on the Eastern Seaboard, is a major destination for Acadia National Park visitors. Managing vegetation impacts on Cadillac is extremely challenging given the high use and fragile environmental conditions. A number of direct and indirect management strategies have been employed to help to reduce the amount of vegetation impact. The...

Genotoxicity of diesel engine emissions during combustion of vegetable oils, mineral oil, and their blends; Gentoxizitaet von Dieselmotoremissionen bei Verbrennung von Pflanzenoelen, Mineraloeldiesel und deren Mischkraftstoffen

Energy Technology Data Exchange (ETDEWEB)

Buenger, Joern

2013-07-09

High particle emissions and strong mutagenic effects were observed after combustion of vegetable oil in diesel engines. This study tested the hypothesis that these results are affected by the amount of unsaturated or polyunsaturated fatty acids of vegetable oils and that blends of diesel fuel and vegetable oil are mutagenic. Three different vegetable oils (linseed oil, LO; palm tree oil, PO; rapeseed oil, RO), blends of 20% vegetable oil and 80% diesel fuel (B20) and 50% vegetable oil and 50% diesel fuel (B50) as well as common diesel fuel (DF) were combusted in a heavy duty diesel engine. The exhaust was investigated for particle emissions and its mutagenic effect in comparison to emissions of DF. The engine was operated using European Stationary Cycle. Particle mass was determined gravimetrically while mutagenicity was determined using the bacterial reverse mutation assay with tester strains TA98 and TA100. Combustion of LO caused the largest amount of total particulate matter (TPM). In comparison to DF it particularly raised the soluble organic fraction (SOF). RO presented second highest TPM and SOF, followed by PO which was scarcely above DF. B50 revealed the lowest amount of TPM while B20 reached as high as DF. RO revealed the highest number of mutations of the vegetable oils closely followed by LO. PO was less mutagenic, but still induced stronger effects than DF. B50 showed higher mutagenic potential than B20. While TPM and SOF were strongly correlated with the content of polyunsaturated fatty acids in the vegetable oils, mutagenicity had a significant correlation with the amount of total unsaturated fatty acids. Vegetable oil blends seem to be less mutagenic than the pure oils with a shifted maximum compared to blends with biodiesel and DF. This study supports the hypothesis that numbers of double bounds in unsaturated fatty acids of vegetable oils combusted in diesel engines influence the amount of emitted particles and the mutagenicity of the exhaust. And

Rapid characterisation of vegetation structure to predict refugia and climate change impacts across a global biodiversity hotspot.

Directory of Open Access Journals (Sweden)

Antonius G T Schut

Full Text Available Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR. However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR data and Red Green and Blue (RGB imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region. Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8 and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R(2 of 0.8-0.9 allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented

Vegetation Variability And Its Effect On Monsoon Rainfall Over South East Asia: Observational and Modeling Results

Science.gov (United States)

Sarkar, S.; Peters-Lidard, C.; Chiu, L.; Kafatos, M.

2005-12-01

Increasing population and urbanization have created stress on developing nations. The quickly shifting patterns of vegetation change in different parts of the world have given rise to the pertinent question of feedback on the climate prevailing on local to regional scales. It is now known with some certainty, that vegetation changes can affect the climate by influencing the heat and water balance. The hydrological cycle particularly is susceptible to changes in vegetation. The Monsoon rainfall forms a vital link in the hydrological cycle prevailing over South East Asia This work examines the variability of vegetation over South East Asia and assesses its impact on the monsoon rainfall. We explain the role of changing vegetation and show how this change has affected the heat and energy balance. We demonstrate the role of vegetation one season earlier in influencing rainfall intensity over specific areas in South East Asia and show the ramification of vegetation change on the summer rainfall behavior. The vegetation variability study specifically focuses on India and China, two of the largest and most populous nations. We have done an assessment to find out the key meteorological and human induced parameters affecting vegetation over the study area through a spatial analysis of monthly NDVI values. This study highlights the role of monsoon rainfall, regional climate dynamics and large scale human induced pollution to be the crucial factors governing the vegetation and vegetation distribution. The vegetation is seen to follow distinct spatial patterns that have been found to be crucial in its eventual impact on monsoon rainfall. We have carried out a series of sensitivity experiments using a land surface hydrologic modeling scheme. The vital energy and water balance parameters are identified and the daily climatological cycles are examined for possible change in behavior for different boundary conditions. It is found that the change from native deciduous forest

Climate and Vegetation Effects on Temperate Mountain Forest ...

Science.gov (United States)

Current forest composition may be resilient to typical climatic variability; however, climate trends, combined with projected changes in species composition, may increase tree vulnerability to water stress. A shift in forest composition toward tree species with higher water use has implications for biogenic emissions and deposition of reactive nitrogen and carbon compounds. Forest evapotranspiration (ET) can vary greatly at daily and seasonal time scales, but compared to carbon fluxes, often exhibits relatively consistent inter-annual behavior. The processes controlling ET involve the combined effects of physical and biological factors. Atmospheric conditions that promote high ET, consisting of high radiation and vapor pressure deficit (D), are often characterized by rainless periods when soil water supply to vegetation may be limiting and plant stomata may close to prevent excessive water loss. In contrast, periods of high ecosystem water availability require frequent precipitation and are characterized by low D. Thus, the combination of these contrasting conditions throughout a growing season may explain some of the consistency in ET. Additionally, vegetation composition is also an important factor in determining ET. In mixed species forests, physiological differences in water use strategies (e.g. isohydric/anisohydric species) can produce conservative water use throughout wet and dry phases of the growing season. Furthermore, transpiration by evergreen specie

EVALUATING THE TECHNICAL EFFICIENCY OF SMALLHOLDER VEGETABLE FARMS IN DIVERSE AGROECOLOGICAL REGIONS OF NEPAL

Directory of Open Access Journals (Sweden)

Rudra Bahadur Shrestha

2017-01-01

Full Text Available Enhancing the efficiency of vegetable farms is crucial to increase the vegetable outputs for meeting the demand for growing population. This study evaluated the technical efficiency and explored factors determining the efficiencies of smallholder vegetable farms in diversified agro-ecological regions using Stochastic Frontier Analysis (SFA with cross-section data collected in 2013. The results revealed that average technical efficiency was found to be 0.77 and the variance parameters were highly significant indicating that the inefficiency existed in vegetable farms. The inefficiency gap could improve by operating the farms at the frontier level. The input variables consisting of land, labor, animal power, fertilizer, compost, pesticide, and capital were proved to be the important factors in determining the level of outputs. Meanwhile, the major sources of the inefficiencies identified were: age of farmer, training to the farmers, and infrastructure development. The efficiency in vegetable production can be improved by allocating input resources at the optimum levels, encouraging younger farmers in vegetable production, increasing training and extension activities, enhancing market access to the farmers, and developing infrastructures with regard to vegetable production.

Carbohydrates and phenols as quantitative molecular vegetation proxies in peats

Science.gov (United States)

Kaiser, K.; Benner, R. H.

2012-12-01

Vegetation in peatlands is intricately linked to local environmental conditions and climate. Here we use chemical analyses of carbohydrates and phenols to reconstruct paleovegetation in peat cores collected from 56.8°N (SIB04), 58.4°N (SIB06), 63.8°N (G137) and 66.5°N (E113) in the Western Siberian Lowland. Lignin phenols (vanillyl and syringyl phenols) were sensitive biomarkers for vascular plant contributions and provided additional information on the relative contributions of angiosperm and gymnosperm plants. Specific neutral sugar compositions allowed identification of sphagnum mosses, sedges (Cyperaceae) and lichens. Hydroxyphenols released by CuO oxidation were useful tracers of sphagnum moss contributions. The three independent molecular proxies were calibrated with a diverse group of peat-forming plants to yield quantitative estimates (%C) of vascular plant, sphagnum moss and lichen contributions in peat core samples. Correlation analysis indicated the three molecular proxies produced fairly similar results for paleovegetation compositions, generally within the error interval of each approach (≤26%). The lignin-based method generally lead to higher estimates of vascular plant vegetation. Several significant deviations were also observed due to different reactivities of carbohydrate and phenolic polymers during peat decomposition. Rapid vegetation changes on timescales of 50-200 years were observed in the southern cores SIB04 and SIB06 over the last 2000 years. Vanillyl and syringyl phenol ratios indicated these vegetation changes were largely due to varying inputs of angiosperm and gymnosperm plants. The northern permafrost cores G137 and E113 showed a more stable development. Lichens briefly replaced sphagnum mosses and vascular plants in both of these cores. Shifts in vegetation did not correlate well with Northern hemisphere climate variability over the last 2000 years. This suggested that direct climate forcing of peatland dynamics was overridden

Climate and vegetation in a semi-arid savanna: Development of a climate–vegetation response model linking plant metabolic performance to climate and the effects on forage availability for large herbivores

Directory of Open Access Journals (Sweden)

Armin H. Seydack

2012-02-01

Developing the climate–vegetation response model involved three main components, namely (1 defining indicators of forage availability to herbivores (nitrogen productivity, nitrogen quality, carbon-nutrient quality, (2 identifying herbivore species guilds of similar nutritional requirements with respect to these indicators [bulk feeders with tolerance to fibrous herbage (buffalo, waterbuck, bulk feeders with preference for high nitrogen quality forage (short grass preference grazers: blue wildebeest and zebra and selective feeders where dietary items of relatively high carbon-nutrient quality represented key forage resources (selective grazers: sable antelope, roan antelope, tsessebe, eland] and (3 developing a process model where the expected effects of plant metabolic responses to climate on key forage resources were made explicit. According to the climate–vegetation response model both shorter-term transient temperature acclimation pulses and longer-term shifts in plant metabolic functionality settings were predicted to have occurred in response to temperature trends over the past century. These temperature acclimation responses were expected to have resulted in transient pulses of increased forage availability (increased nitrogen- and carbon-nutrient quality, as well as the progressive long-term decline of the carbon-nutrient quality of forage. Conservation implications: The climate–vegetation response model represents a research framework for further studies contributing towards the enhanced understanding of landscape-scale functioning of savanna systems with reference to the interplay between climate, vegetation and herbivore population dynamics. Gains in such understanding can support sound conservation management.

Perception of non-communicable diseases predicts consumption of fruits and vegetables

Directory of Open Access Journals (Sweden)

Charles Surjadi

2012-12-01

Full Text Available Background Nutrition has come to the fore as one of the major modifiable determinants of chronic disease. Establishing healthy eating habits during adolescence is important given that fruit and vegetable consumption has long-term health-protective benefits. The objective of this study was to investigate the determinant factors of fruit and vegetable consumption habits among Padang inhabitants Methods We conducted a questionnaire-based rapid assessment of 150 respondents who came from different settings: The questionnaire consisted of items on personal characteristics such as age, working status, gender, and personal knowledge of the subjects about the cause of non-communicable diseases (NCDs and their activities to prevent NCDs. Bivariate analysis was applied to look for variables significantly related to healthy eating (vegetable and fruit consumption. We applied multiple logistic regression to look for the best model to explain factors related to regular fruit and vegetable consumption. Results The age range of the subjects was 14 to 76 years, 60% of subjects were women, and 40% were men. The study indicated that 64.7% of the respondents perceived that eating habits relate to NCD, while 67.3% consumed fruits and vegetables regularly. Multivariate logistic regression analysis indicated that gender (O.R.=2.74; 95% C.I. 1.54-5.27 and perception of NCD as being related to healthy eating (O.R.=5.62;95% C.I. 2.93-10.76 were significantly related to regular fruit and vegetable consumption. Conclusion This study demonstrated that perception of NCD was the most determinant factor of regular fruit and vegetable consumption. Activities to improve practice of regular fruit and vegetable consumption are part of control of NCD risk factors.

Shift Work Disorder and Mental and Physical Effects of Shift Work

Directory of Open Access Journals (Sweden)

Pinar Guzel Ozdemir

2018-03-01

Full Text Available With the growing prevalence of shift work all over the the world, the relationship between the daily lives of irregular lifestyles and rhythms is being investigated for those working as shift workers and their families. The effect of shift work on physical and mental health is a very important field of research in recent years. The onset and persistence of medical complications in shift workers includes impaired synchronization between work schedule rhythms and circadian clock. In this context, studies have been carried out showing the increased risk of sleep-wake disorders, gastrointestinal problems, and cardiovascular diseases. There is little information about the actual frequency, effect on health and treatment of shift work disorder, known as circadian rhythm sleep disorder. Shift work disorder includes insomnia and/or excessive sleepiness related with the work schedule. The aim of this rewiev, mentioning about the physical and mental effects of shift work, and to provide information about the diagnosis, clinic and treatment methods of shift-work disorder.

Mode Shift Control for a Hybrid Heavy-Duty Vehicle with Power-Split Transmission

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Kun Huang

2017-02-01

Full Text Available Given that power-split transmission (PST is considered to be a major powertrain technology for hybrid heavy-duty vehicles (HDVs, the development and application of PST in the HDVs make mode shift control an essential aspect of powertrain system design. This paper presents a shift schedule design and torque control strategy for a hybrid HDV with PST during mode shift, intended to reduce the output torque variation and improve the shift quality (SQ. Firstly, detailed dynamic models of the hybrid HDV are developed to analyze the mode shift characteristics. Then, a gear shift schedule calculation method including a dynamic shift schedule and an economic shift schedule is provided. Based on the dynamic models and the designed shift schedule, a mode shift performance simulator is built using MATLAB/Simulink, and simulations are carried out. Through analysis of the dynamic equations, it is seen that the inertia torques of the motor–generator lead to the occurrence of transition torque. To avoid the unwanted transition torque, we use a mode shift control strategy that coordinates the motor–generator torque to compensate for the transition torque. The simulation and experimental results demonstrate that the output torque variation during mode shift is effectively reduced by the proposed control strategy, thereby improving the SQ.

Fruits and vegetables dehydration

International Nuclear Information System (INIS)

De Ita, A; Flores, G; Franco, F

2015-01-01

Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different

Fruits and vegetables dehydration

Science.gov (United States)

de Ita, A.; Flores, G.; Franco, F.

2015-01-01

Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different.

Extent of Microbial Contamination of Refined and Unrefined Vegetable oils sold in South-west Nigeria

Directory of Open Access Journals (Sweden)

Oluwafemi Flora

2018-04-01

Full Text Available Oils constitute a major source of plant-based protein. A major limitation to optimal oil consumption in sub-tropical region is fungal infestation and consequent mycotoxin contamination. Ten refined and eight unrefined vegetable oils were randomly purchase from open markets and screened for microbial contamination using standard microbial procedures. Twenty six fungi isolates were obtained from the vegetable oil samples, the isolates were identified as Aspergillus fumigatus (43.0%, Mucor (17.9%, Saccharomyces cerevisiae (10.7%, Aspergillus niger (7.1%, Aspergillus flavus (7.1%, Penicillium spp (7.1%, Aspergillus oryzae (3.6%, Mucor (17.9% and Rhizopus spp (3.6%. Five out of the ten refined vegetable oil samples had no fungal contamination. A. flavus and A. oryzae were absent in all the refined oil samples while A. niger was absent in all the unrefined oil samples. Isolation of mycotoxigenic fungi such as Aspergillus spp. is of vital importance in the food industry. Education and training of processors and consumers is recommended.

Post-fire vegetation behaviour in large burnt scars from 2005 fire season in Spain

Science.gov (United States)

Bastos, A.; Gouveia, C. M.; DaCamara, C. C.; Trigo, R. M.

2012-04-01

Wildfires have a wide diversity of impacts on landscape which, in turn, depend on the interaction of fire regimes (e.g. intensity, extent, frequency) and the response of vegetation to them in short and long-terms. The increase in erosion rates and the loss of nutrients by runoff in the first months following the fire are among the major impacts of wildfires. A minimum of 30% of vegetation cover is enough to protect soils against erosion but vegetation may require a long period to reach this threshold after severe fires. Since erosion risk is strongly linked to vegetation recovery rates, post-fire vegetation monitoring becomes crucial in land management. Fire regimes in the Mediterranean have been changing in the past decades due to modifications in both socio-economic and climate patterns. Although many vegetation species in Mediterranean ecosystems are adapted to wildfires, changes in fire regime characteristics affect the ability of ecosystems to recover to their previous state. In Spain, fire is an important driver of changes in landscape composition, leading to dominance of shrubland following fire and to a major decrease of pine woodlands (Viedma et al., 2006). Remote sensing is a powerful tool in land management, allowing vegetation monitoring on large spatial scales for relatively long periods of time. In order to assess vegetation dynamics, monthly NDVI data from 1998-2009 from SPOT/VEGETATION at 1km spatial resolution over the Iberian Peninsula were used. This work focuses on 2005 fire season in Spain, which registered the highest amount of burnt area since 1994, with more than 188000 ha burnt. Burnt scars in this fire season were identified by cluster analysis. Post-fire vegetation recovery was assessed based on the monoparametric model developed by Gouveia et al. (2010) that was applied to four large scars located in different geographical settings with different land cover characteristics. While the two northern regions presented fast recovery, in the

Non-occupational physical activity levels of shift workers compared with non-shift workers

Science.gov (United States)

Loef, Bette; Hulsegge, Gerben; Wendel-Vos, G C Wanda; Verschuren, W M Monique; Bakker, Marije F; van der Beek, Allard J; Proper, Karin I

2017-01-01

Objectives Lack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between shift workers and non-shift workers. Furthermore, exposure–response relationships for frequency of night shifts and years of shift work regarding non-occupational PA levels were studied. Methods Data of 5980 non-shift workers and 532 shift workers from the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) were used in these cross-sectional analyses. Time spent (hours/week) in different PA types (walking/cycling/exercise/chores) and intensities (moderate/vigorous) were calculated based on self-reported PA. Furthermore, sports were operationalised as: playing sports (no/yes), individual versus non-individual sports, and non-vigorous-intensity versus vigorous-intensity sports. PA levels were compared between shift workers and non-shift workers using Generalized Estimating Equations and logistic regression. Results Shift workers reported spending more time walking than non-shift workers (B=2.3 (95% CI 1.2 to 3.4)), but shift work was not associated with other PA types and any of the sports activities. Shift workers who worked 1–4 night shifts/month (B=2.4 (95% CI 0.6 to 4.3)) and ≥5 night shifts/month (B=3.7 (95% CI 1.8 to 5.6)) spent more time walking than non-shift workers. No exposure–response relationships were found between years of shift work and PA levels. Conclusions Shift workers spent more time walking than non-shift workers, but we observed no differences in other non-occupational PA levels. To better understand if and how PA plays a role in the negative health consequences of shift work, our findings need to be confirmed in future studies. PMID:27872151

Surface energy exchanges over contrasting vegetation types on a subtropical sand island

Science.gov (United States)

Gray, Michael; McGowan, Hamish; Lowry, Andrew; Guyot, Adrien

2017-04-01

The surface energy balance of subtropical coastal vegetation communities has thus far received little attention. Here we present a multi-year observational data set using the eddy covariance method to quantify for the first time the surface energy balance over three contrasting vegetation types on a subtropical sand island in eastern Australia: a periodically inundated sedge swamp, an exotic pine plantation and a coastal heath. Maximum daily sensible heat flux varied between sites but was typically > 280 Wm-2 in the coastal heath and pine plantation but no more than 250 Wm-2 in the swamp when dry and 1. The partitioning of energy, as represented by β, is similar to a variety of Australian ecosystems, and a range of coastal vegetation types in other latitudes, but differs from other tropical or subtropical locations which have strongly seasonal rainfall patterns and therefore a switch from β > 1 before rainfall to β changes in background meteorology with the most important influences being net radiation, absolute humidity, and rainfall. The main factor differentiating the sites was soil water content, with the remnant coastal heath and swamp having ready access to water but the exotic pine plantation having much drier soils. Should the current balance between remnant vegetation and the pine plantation undergo changes there would be a corresponding shift in the surface energy balance of the island as a whole, and altered plant water use may lead to reduced water table depth, important because the groundwater of the local islands is used as part of a regional water grid. A better understanding of the response of coastal vegetation to atmospheric forcing will enable more informed decision making on land use changes, as coastal regions the world over face development pressure.

Vegetation monitoring for Guatemala: a comparison between simulated VIIRS and MODIS satellite data

Science.gov (United States)

Boken, Vijendra K.; Easson, Gregory L.; Rowland, James

2010-01-01

The advanced very high resolution radiometer (AVHRR) and moderate resolution imaging spectroradiometer (MODIS) data are being widely used for vegetation monitoring across the globe. However, sensors will discontinue collecting these data in the near future. National Aeronautics and Space Administration is planning to launch a new sensor, visible infrared imaging radiometer suite (VIIRS), to continue to provide satellite data for vegetation monitoring. This article presents a case study of Guatemala and compares the simulated VIIRS-Normalized Difference Vegetation Index (NDVI) with MODIS-NDVI for four different dates each in 2003 and 2005. The dissimilarity between VIIRS-NDVI and MODIS-NDVI was examined on the basis of the percent difference, the two-tailed student's t-test, and the coefficient of determination, R 2. The per cent difference was found to be within 3%, the p-value ranged between 0.52 and 0.99, and R 2 exceeded 0.88 for all major types of vegetation (basic grains, rubber, sugarcane, coffee and forests) found in Guatemala. It was therefore concluded that VIIRS will be almost equally capable of vegetation monitoring as MODIS.

Soil respiration shifts as drought-induced tree substitution advances from Scots pine to Holm oak forest

Science.gov (United States)

Barba, Josep; Curiel Yuste, Jorge; Poyatos, Rafael; Janssens, Ivan A.; Lloret, Francisco

2014-05-01

There is more and more evidences that the current global warming trend and the increase of frequency and intensity of drought events during the last decades in the Northern hemisphere are currently producing an increment of drought-induced forest die-off events, being the Mediterranean region one of the most affected areas. This drought-induced mortality could lead in a vegetation shift with unpredicted consequences in carbon pools, where soils are the most determinant factor in this carbon balance as they contain over two-thirds of carbon on forest ecosystems. There are several uncertainties related on the interaction between soil, environmental conditions and vegetation shifts that could modify their capability to be net carbon sinks or sources in a warming context. We studied soil respiration and its heterotrophic (RH) and autotrophic (Ra) (split in fine roots [Rr] and mycorrhizal respiration [Rs]) components in a mixed Mediterranean forest where Scots pine (Pinus sylvestris L.) are suffering from drought-induced die-off and replaced by Holm oak (Quercus ilex L.) as the dominant tree species. Soil respiration fluxes and its fractions were measured every two weeks during one year at four stages of the substitution process (non defoliated pines [NDP], defoliated pines [DFP], dead pines [DP] and Holm oak [HO]), using the mesh exclusion method. The aims were (i) to describe soil respiration fluxes in a drought-induced secondary successional process, (ii) to test whether the changes in vegetation affected soil respiration fluxes and (iii) to determine the influence of environmental and abiotic variables on the different soil respiration fractions. Total soil respiration was 10.10±6.17 TC ha-1 y-1, RH represented the 67% of the total, Ra represented the 34% of the total, and Rr and Rs were the 22 and 12%, respectively. Significant differences were found in total soil respiration and RH between NDP and HO, being lower in HO than in NDP (34% in total and 48% in RH). No

Analysis of a micropolarizer array-based simultaneous phase-shifting interferometer.

Science.gov (United States)

Novak, Matt; Millerd, James; Brock, Neal; North-Morris, Michael; Hayes, John; Wyant, James

2005-11-10

Recent technological innovations have enabled the development of a new class of dynamic (vibration-insensitive) interferometer based on a CCD pixel-level phase-shifting approach. We present theoretical and experimental results for an interferometer based on this pixelated phase-shifting technique. Analyses of component errors and instrument functionality are presented. We show that the majority of error sources cause relatively small magnitude peak-to-valley errors in measurement of the order of 0.002-0.005lambda. These errors are largely mitigated by high-rate data acquisition and consequent data averaging.

Method of producing vegetable puree

DEFF Research Database (Denmark)

2004-01-01

A process for producing a vegetable puree, comprising the sequential steps of: a)crushing, chopping or slicing the vegetable into pieces of 1 to 30 mm; b) blanching the vegetable pieces at a temperature of 60 to 90°C; c) contacted the blanched vegetable pieces with a macerating enzyme activity; d......) blending the macerated vegetable pieces and obtaining a puree....

Enhanced preference for high-fat foods following a simulated night shift.

Science.gov (United States)

Cain, Sean W; Filtness, Ashleigh J; Phillips, Craig L; Anderson, Clare

2015-05-01

Shift workers are prone to obesity and associated co-morbidities such as diabetes and cardiovascular disease. Sleep restriction associated with shift work results in dramatic endocrine and metabolic effects that predispose shift workers to these adverse health consequences. While sleep restriction has been associated with increased caloric intake, food preference may also play a key role in weight gain associated with shift work. This study examined the impact of an overnight simulated night shift on food preference. Sixteen participants [mean 20.1, standard deviation (SD) 1.4 years; 8 women] underwent a simulated night shift and control condition in a counterbalanced order. On the following morning, participants were provided an opportunity for breakfast that included high- and low-fat food options (mean 64.8% and 6.4% fat, respectively). Participants ate significantly more high-fat breakfast items after the simulated night shift than after the control condition [167.3, standard error of the mean (SEM 28.7) g versus 211.4 (SEM 35.6) g; P=0.012]. The preference for high-fat food was apparent among the majority of individuals following the simulated night shift (81%), but not for the control condition (31%). Shift work and control conditions did not differ, however, in the total amount of food or calories consumed. A simulated night shift leads to preference for high-fat food during a subsequent breakfast opportunity. These results suggest that food choice may contribute to weight-related chronic health problems commonly seen among night shift workers.

The experience of being a shift-leader in a hospital ward.

Science.gov (United States)

Goldblatt, Hadass; Granot, Michal; Admi, Hanna; Drach-Zahavy, Anat

2008-07-01

This paper is a report of a study to explore the experience of being a shift-leader, and how these nurses view the management of their shift. Professional demands on skilled and capable shift-leaders, who competently handle multi-disciplinary staff and patients, as well as operations and information, call for the development of efficient nursing leadership roles. Nevertheless, knowledge of shift-leaders' perspectives concerning their task management and leadership styles is relatively limited. Twenty-eight Registered Nurses working in an Israeli medical centre participated in this qualitative study. Data were gathered through in-depth interviews conducted in two phases between February and October 2005: three focus group interviews (phase 1) followed by seven individual interviews (phase 2). Content analysis revealed two major themes which constitute the essence of being a shift-leader: (1) a burden of responsibility, where the shift-leader moves between positions of maximum control and delegating some responsibility to other nurses; (2) the role's temporal dimension, expressed as a strong desire to reach the end of the shift safely, and taking managerial perspectives beyond the boundaries of the specific shift. The core of the shift-leader's position is an immense sense of responsibility. However, this managerial role is transient and therefore lacks an established authority. A two-dimensional taxonomy of these themes reveals four types of potential and actual coping among shift-leaders, indicating the need to train them in leadership skills and systemic thinking. Interventions to limit the potential stress hazards should be focused simultaneously on shift-leaders themselves and on job restructuring.

Vegetables. Learning Activity Pack and Instructor's Guide 5.14. Commercial Foods and Culinary Arts Competency-Based Series. Section 5: Basic Food Preparation.

Science.gov (United States)

Florida State Univ., Tallahassee. Center for Studies in Vocational Education.

This document consists of a learning activity packet (LAP) for the student and an instructor's guide for the teacher. The LAP is intended to acquaint occupational home economics students with the major types of vegetables, with the procedures for storing vegetables, and with the general rules and methods of vegetable cookery. Illustrated…

Vegetation and environmental dynamics in the Páramo of Jimbura region in the southeastern Ecuadorian Andes during the late Quaternary

Science.gov (United States)

Villota, Andrea; León-Yánez, Susana; Behling, Hermann

2012-12-01

The last 15,000 years of vegetation, fire and climate history were reconstructed from the Laguna Natosa Peat bog core (3600 m elevation) in the Páramo of Jimbura region in the Cordillera Real, close to the Peruvian border of southern Ecuador in the southernmost part of the Andean depression. The pollen record, dated by 5 radiocarbon dates, indicates that during the late Glacial (ca. 15,000-12,000 cal yr BP) a gradual expansion of mountain forest, restricting the páramo vegetation to small patches, and a shift of the forest line to higher elevation took place; reflecting an increase in temperature. However, a clear signal of the warmer Bølling/Allerød interstadial and the cooler Younger Dryas period, are not reflected in the record. During the transition from the late Glacial to the early/mid-Holocene (ca. 12,000-4800 cal yr BP), tree taxa such as Hedyosmum and Podocarpaceae are well represented, suggesting that the upper forest line, especially in the mid-Holocene, reached slightly higher elevations than at present. Hence, páramo vegetation was limited, indicating warmer climatic conditions for the early to mid-Holocene period than today. The late Holocene from 4800 cal yr BP until the present is characterized by higher occurrences of páramo taxa. During this period, the upper forest line shifted downwards giving room to the expansion of the páramo vegetation to its current size. Fire was rare during the late Glacial period but became more frequent after about 8000 cal yr BP, probably due to the dry event during the mid-Holocene and increased human activity.

Impacts of 21st century climate changes on flora and vegetation in Denmark

International Nuclear Information System (INIS)

Skov, Flemming; Nygaard, Bettina; Wind, Peter; Floejgaard, Camilla; Borchsenius, Finn; Normand, Signe; Balslev, Henrik; Svenning, Jens-Christian

2009-01-01

In this paper we examined the potential impacts of predicted climatic changes on the flora and vegetation in Denmark using data from a digital database on the natural vegetation of Europe. Climate scenarios A2 and B2 were used to find regions with present climatic conditions similar to Denmark's climate in the year 2100. The potential natural vegetation of Denmark today is predominantly deciduous forest that would cover more than 90% of the landscape. Swamps, bogs, and wet forest would be found under moist or wet conditions. Dwarf shrub heaths would be naturally occurring on poor soils along the coast together with dune systems and salt-marsh vegetation. When comparing the natural vegetation of Denmark to the vegetation of five future-climate analogue areas, the most obvious trend is a shift from deciduous to thermophilous broadleaved forest currently found in Southern and Eastern Europe. A total of 983 taxa were recorded for this study of which 539 were found in Denmark. The Soerensen index was used to measure the floristic similarity between Denmark and the five subregions. Deciduous forest, dwarf shrub heath, and coastal vegetation were treated in more detail, focusing on potential new immigrant species to Denmark. Finally, implications for management were discussed. The floristic similarity between Denmark and regions in Europe with a climate similar to what is expected for Denmark in year 2100 was found to vary between 48-78%, decreasing from North to South. Hence, it seems inevitable that climate changes of the magnitudes foreseen will alter the distribution of individual species and the composition of natural vegetation units. Changes, however, will not be immediate. Historic evidence shows a considerable lag in response to climatic change under natural conditions, but little is known about the effects of human land-use and pollution on this process. Facing such uncertainties we suggested that a dynamic strategy based on modeling, monitoring and adaptive

Impacts of 21st century climate changes on flora and vegetation in Denmark

Science.gov (United States)

Skov, Flemming; Nygaard, Bettina; Wind, Peter; Borchsenius, Finn; Normand, Signe; Balslev, Henrik; Fløjgaard, Camilla; Svenning, Jens-Christian

2009-11-01

In this paper we examined the potential impacts of predicted climatic changes on the flora and vegetation in Denmark using data from a digital database on the natural vegetation of Europe. Climate scenarios A2 and B2 were used to find regions with present climatic conditions similar to Denmark's climate in the year 2100. The potential natural vegetation of Denmark today is predominantly deciduous forest that would cover more than 90% of the landscape. Swamps, bogs, and wet forest would be found under moist or wet conditions. Dwarf shrub heaths would be naturally occurring on poor soils along the coast together with dune systems and salt-marsh vegetation. When comparing the natural vegetation of Denmark to the vegetation of five future-climate analogue areas, the most obvious trend is a shift from deciduous to thermophilous broadleaved forest currently found in Southern and Eastern Europe. A total of 983 taxa were recorded for this study of which 539 were found in Denmark. The Sørensen index was used to measure the floristic similarity between Denmark and the five subregions. Deciduous forest, dwarf shrub heath, and coastal vegetation were treated in more detail, focusing on potential new immigrant species to Denmark. Finally, implications for management were discussed. The floristic similarity between Denmark and regions in Europe with a climate similar to what is expected for Denmark in year 2100 was found to vary between 48-78%, decreasing from North to South. Hence, it seems inevitable that climate changes of the magnitudes foreseen will alter the distribution of individual species and the composition of natural vegetation units. Changes, however, will not be immediate. Historic evidence shows a considerable lag in response to climatic change under natural conditions, but little is known about the effects of human land-use and pollution on this process. Facing such uncertainties we suggested that a dynamic strategy based on modeling, monitoring and adaptive

Impacts of 21st century climate changes on flora and vegetation in Denmark

Energy Technology Data Exchange (ETDEWEB)

Skov, Flemming; Nygaard, Bettina; Wind, Peter; Floejgaard, Camilla [Department of Wildlife Ecology and Biodiversity, National Environmental Research Institute, Aarhus University, Grenaavej 14, DK-8410 Roende (Denmark); Borchsenius, Finn; Normand, Signe; Balslev, Henrik; Svenning, Jens-Christian, E-mail: fs@dmu.d [Department of Biological Sciences, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C (Denmark)

2009-11-01

In this paper we examined the potential impacts of predicted climatic changes on the flora and vegetation in Denmark using data from a digital database on the natural vegetation of Europe. Climate scenarios A2 and B2 were used to find regions with present climatic conditions similar to Denmark's climate in the year 2100. The potential natural vegetation of Denmark today is predominantly deciduous forest that would cover more than 90% of the landscape. Swamps, bogs, and wet forest would be found under moist or wet conditions. Dwarf shrub heaths would be naturally occurring on poor soils along the coast together with dune systems and salt-marsh vegetation. When comparing the natural vegetation of Denmark to the vegetation of five future-climate analogue areas, the most obvious trend is a shift from deciduous to thermophilous broadleaved forest currently found in Southern and Eastern Europe. A total of 983 taxa were recorded for this study of which 539 were found in Denmark. The Soerensen index was used to measure the floristic similarity between Denmark and the five subregions. Deciduous forest, dwarf shrub heath, and coastal vegetation were treated in more detail, focusing on potential new immigrant species to Denmark. Finally, implications for management were discussed. The floristic similarity between Denmark and regions in Europe with a climate similar to what is expected for Denmark in year 2100 was found to vary between 48-78%, decreasing from North to South. Hence, it seems inevitable that climate changes of the magnitudes foreseen will alter the distribution of individual species and the composition of natural vegetation units. Changes, however, will not be immediate. Historic evidence shows a considerable lag in response to climatic change under natural conditions, but little is known about the effects of human land-use and pollution on this process. Facing such uncertainties we suggested that a dynamic strategy based on modeling, monitoring and

Estimating vegetation dryness to optimize fire risk assessment with spot vegetation satellite data in savanna ecosystems

Science.gov (United States)

Verbesselt, J.; Somers, B.; Lhermitte, S.; van Aardt, J.; Jonckheere, I.; Coppin, P.

2005-10-01

The lack of information on vegetation dryness prior to the use of fire as a management tool often leads to a significant deterioration of the savanna ecosystem. This paper therefore evaluated the capacity of SPOT VEGETATION time-series to monitor the vegetation dryness (i.e., vegetation moisture content per vegetation amount) in order to optimize fire risk assessment in the savanna ecosystem of Kruger National Park in South Africa. The integrated Relative Vegetation Index approach (iRVI) to quantify the amount of herbaceous biomass at the end of the rain season and the Accumulated Relative Normalized Difference vegetation index decrement (ARND) related to vegetation moisture content were selected. The iRVI and ARND related to vegetation amount and moisture content, respectively, were combined in order to monitor vegetation dryness and optimize fire risk assessment in the savanna ecosystems. In situ fire activity data was used to evaluate the significance of the iRVI and ARND to monitor vegetation dryness for fire risk assessment. Results from the binary logistic regression analysis confirmed that the assessment of fire risk was optimized by integration of both the vegetation quantity (iRVI) and vegetation moisture content (ARND) as statistically significant explanatory variables. Consequently, the integrated use of both iRVI and ARND to monitor vegetation dryness provides a more suitable tool for fire management and suppression compared to other traditional satellite-based fire risk assessment methods, only related to vegetation moisture content.

1989 vegetation studies at Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

1990-02-01

The overall purpose of the 1989 vegetation ecology studies was to describe the existing vegetation and baseline ecological conditions of the Yucca Mountain study area, before further disturbances due to site characterization occur. Extensive disturbances have already occurred due to preliminary studies associated with the waste repository. If the site is determined to be unsuitable for a waste repository, then reclamation of disturbed sites will be required. Biotic conditions are described within both regional and local contexts because the intensity of local disturbances may result in impacts to outlying areas. The most detailed data collection was conducted in the Focused Baseline Study Area where site characterization activities will be concentrated. Less detailed information was obtained for adjacent areas in the Core Study Area and Cumulative Assessment Study Area. The major tasks of this study were as follows: describe and map the vegetation of the Yucca Mountain study area; identify important relationships between the biotic and physical elements of the ecosystem; identify unique or sensitive resources; preliminary assessment of the baseline ecological conditions of the area

Reduced Tolerance to Night Shift in Chronic Shift Workers: Insight From Fractal Regulation.

Science.gov (United States)

Li, Peng; Morris, Christopher J; Patxot, Melissa; Yugay, Tatiana; Mistretta, Joseph; Purvis, Taylor E; Scheer, Frank A J L; Hu, Kun

2017-07-01

Healthy physiology is characterized by fractal regulation (FR) that generates similar structures in the fluctuations of physiological outputs at different time scales. Perturbed FR is associated with aging and age-related pathological conditions. Shift work, involving repeated and chronic exposure to misaligned environmental and behavioral cycles, disrupts circadian coordination. We tested whether night shifts perturb FR in motor activity and whether night shifts affect FR in chronic shift workers and non-shift workers differently. We studied 13 chronic shift workers and 14 non-shift workers as controls using both field and in-laboratory experiments. In the in-laboratory study, simulated night shifts were used to induce a misalignment between the endogenous circadian pacemaker and the sleep-wake cycles (ie, circadian misalignment) while environmental conditions and food intake were controlled. In the field study, we found that FR was robust in controls but broke down in shift workers during night shifts, leading to more random activity fluctuations as observed in patients with dementia. The night shift effect was present even 2 days after ending night shifts. The in-laboratory study confirmed that night shifts perturbed FR in chronic shift workers and showed that FR in controls was more resilience to the circadian misalignment. Moreover, FR during real and simulated night shifts was more perturbed in those who started shift work at older ages. Chronic shift work causes night shift intolerance, which is probably linked to the degraded plasticity of the circadian control system. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C(4) -C(3) semi-arid vegetation transitions.

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Puttock, Alan; Dungait, Jennifer A J; Bol, Roland; Dixon, Elizabeth R; Macleod, Christopher J A; Brazier, Richard E

2012-10-30

Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C(4) to C(3) vegetation with characteristic δ(13) C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C(4) -C(3) dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 20-22 isotope ratio mass spectrometer to determine bulk δ(13) C values. Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p fluvially eroded sediment from each of the sites, with no significant variation between surface sediment and eroded sediment values. The significant differences in bulk δ(13) C values between sites were dependent on vegetation input. Importantly, these values were robustly expressed in fluvially eroded sediments, suggesting that stable isotope analysis is suitable for tracing sediment fluxes. Due to the prevalent nature of these dryland vegetation transitions in the USA and globally, further development of stable isotope ratio mass spectrometry has provided a valuable tool for enhanced understanding of functional changes in these ecosystems. Copyright © 2012 John Wiley & Sons, Ltd.

Co-evolution of soils and vegetation in the Aísa Valley Experimental Station (Central Pyrenees)

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Serrano Muela, Maria Pilar; Nadal Romero, Estela; Lasanta, Teodoro; María García Ruiz, José

2013-04-01

Soils and vegetation tend to evolve jointly in relation to climate evolution and the impacts of human activity. This study analyzes soil and vegetation characteristics under various plant covers, using information from the Aísa Valley Experimental Station (AVES), Spanish Pyrenees, from 1991 to 2010. The land uses considered were: dense shrub cover, grazing meadow, abandoned field, cereal (barley), abandoned shifting agriculture, active shifting agriculture, burnt1 and burnt2 plots, and in-fallow plot. All the plots were installed on a field abandoned 45 years ago. Some of the plots did not change in plant cover through the study period (e.g., the meadow, cereal and shifting agriculture plots), but others underwent changes in density and composition, such as: (i) The dense shrub cover plot represents the natural evolution of the abandoned field. When the AVES was equipped, this plot was completely dominated by Genista scorpius, with a few stands of Rosa gr. Canina. Twenty years later, Genista scorpius is affected of senescence and shows almost no regeneration capacity. (ii) The abandoned field had previously been cultivated with cereals until 1993. Once abandoned, the progression of plant colonization was very rapid. Firstly with grasses and, 10 years later, with Genista scorpius. At present, this latter occupies more than 50% of the plot. (iii) The evolution of plant colonization in the abandoned shifting agriculture plot was slower than that in the 'normal' abandoned field, mainly because of the differences in fertilization when they were cultivated. (iv) One of the burnt plots evolved from 0% to a coverage of almost 100% in a shot period, whereas the other plot remained with a shrub density of about 60% several years after the fire. Soil samples (superficial and depth) were analyzed to obtain physical and chemical properties: structure, texture, pH, CaCO3, Organic Matter and various anions and cations. The main purpose was to detect differences in the soil

Comparison between remote sensing and a dynamic vegetation model for estimating terrestrial primary production of Africa.

Science.gov (United States)

Ardö, Jonas

2015-12-01

Africa is an important part of the global carbon cycle. It is also a continent facing potential problems due to increasing resource demand in combination with climate change-induced changes in resource supply. Quantifying the pools and fluxes constituting the terrestrial African carbon cycle is a challenge, because of uncertainties in meteorological driver data, lack of validation data, and potentially uncertain representation of important processes in major ecosystems. In this paper, terrestrial primary production estimates derived from remote sensing and a dynamic vegetation model are compared and quantified for major African land cover types. Continental gross primary production estimates derived from remote sensing were higher than corresponding estimates derived from a dynamic vegetation model. However, estimates of continental net primary production from remote sensing were lower than corresponding estimates from the dynamic vegetation model. Variation was found among land cover classes, and the largest differences in gross primary production were found in the evergreen broadleaf forest. Average carbon use efficiency (NPP/GPP) was 0.58 for the vegetation model and 0.46 for the remote sensing method. Validation versus in situ data of aboveground net primary production revealed significant positive relationships for both methods. A combination of the remote sensing method with the dynamic vegetation model did not strongly affect this relationship. Observed significant differences in estimated vegetation productivity may have several causes, including model design and temperature sensitivity. Differences in carbon use efficiency reflect underlying model assumptions. Integrating the realistic process representation of dynamic vegetation models with the high resolution observational strength of remote sensing may support realistic estimation of components of the carbon cycle and enhance resource monitoring, providing suitable validation data is available.

Impact of dam-induced hydrological changes on riparian vegetation

Science.gov (United States)

Tealdi, Stefano; Camporeale, Carlo; Ridolfi, Luca

2010-05-01

Hydrological disturbances are a key factor for the riparian vegetation, which is a highly dynamic ecosystem prone to external forcing. Random fluctuations of water stages drive in fact the alternation of periods of floods and exposure of the vegetated plots. During flooding, the plots are submerged and vegetation is damaged by burial, uprooting and anoxia, while during exposure periods vegetation grows according to the soil moisture content and the phreatic water table depth. The distribution of vegetation along the riparian transect is then directly connected to the stochasticity of river discharges. River damming can have remarkable impacts on the hydrology of a river and, consequently, on the riparian vegetation. Several field studies show how the river regulation induced by artificial reservoirs can greatly modify the statistical moments and the autocorrelation of the discharge time series. The vegetation responds to these changes reducing its overall heterogeneity, declining - substituted by exotic species - and shifting its starting position nearer or far away from the channel center. These latter processes are known as narrowing and widening, respectively. In our work we explore the effects of dam-induced hydrological changes on the narrowing/widening process and on the total biomass along the transect. To this aim we use an eco-hydrological stochastic model developed by Camporeale and Ridolfi [2006], which is able to give a realistic distribution of the biomass along the transect as a function of a few hydrologic, hydraulic and vegetation parameters. We apply the model to an exemplifying case, by investigating the vegetation response to a set of changes in mean discharge and coefficient of variation. The range of these changes is deduced from the analysis of field data in pre- and post-dam conditions. Firstly, we analyze the narrowing/widening process. In particular, we analyze two percentage differences of the starting transversal position with respect to

Using a descriptive social norm to increase vegetable selection in workplace restaurant settings.

Science.gov (United States)

Thomas, Jason M; Ursell, Amanda; Robinson, Eric L; Aveyard, Paul; Jebb, Susan A; Herman, C Peter; Higgs, Suzanne

2017-11-01

Recent work has shown that exposure to social norm messages may enhance the consumption of vegetables. However, the majority of this work has been conducted in laboratories, often with student populations. Little is known about whether this approach can be successfully used in other contexts. In this study, a poster featuring a message based on social norms was tested to examine whether it could increase and maintain the purchase of meals with vegetables in workplace restaurants. A pretest-posttest design with 3 phases was used in 3 workplace restaurants in the United Kingdom. The first 2 weeks formed the preintervention phase, the second 2 weeks the intervention phase, and the last 2 weeks the postintervention phase. During the intervention phase only, posters containing a social norm message relaying information about vegetable purchases of other diners were placed in each restaurant. The main outcome measure was the percentage of meals purchased with vegetables, which was analyzed using Pearson's chi-squared test. Participants were judged to be male (57%), not overweight (75%), and under the age of 60 (98%). The intervention was positively associated with the percentage of meals purchased with vegetables: baseline versus intervention (60% vs. 64% of meals purchased with vegetables; p < .01); intervention versus postintervention (64% vs. 67% of meals purchased with vegetables; p < .01); and baseline versus postintervention (60% vs. 67% of meals purchased with vegetables; p < .001). Social norm messages may increase the purchase of vegetables in workplace settings. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Time to address continued poor vegetable intake in Australia for prevention of chronic disease.

Science.gov (United States)

Chapman, Kathryn; Havill, Michelle; Watson, Wendy L; Wellard, Lyndal; Hughes, Clare; Bauman, Adrian; Allman-Farinelli, Margaret

2016-12-01

Australian and most international Dietary Guidelines recommend people consume more fruits and vegetables (F&V) to maintain a healthy weight and reduce chronic disease risk. Previous Australian and international surveys have shown sub-optimal consumption of F&V. This study aimed to assess adults' F&V consumption, knowledge of recommended servings, readiness to change, barriers/enabling factors, so that this knowledge might be used for campaigns that support improved consumption. An online survey of a representative sample of adults living in New South Wales, Australia (n = 2474) measuring self-reported F&V consumption; attitudes towards F&V consumption; stage of change for increasing F&V; barriers to consumption; and knowledge of cancer-health benefits. F&V consumption was below recommendations, with vegetable consumption notably low. Only 10% of participants ate at least five servings of vegetables/day (median intake was two daily servings), and 57% consumed two servings fruit/day. There was poor recognition that intake of vegetables was inadequate and this was a barrier to improving vegetable consumption; with preferences for other foods, habit and cost also important barriers. Key barriers to increasing fruit intake were habit, preferences for other foods, perishability, and cost. For vegetable consumption, 49% of participants were in the pre-contemplation stage of change, whereas for fruits 56% were in the action/maintenance stage. Sixty-four percent of respondents believed that eating F&V would protect against cancer, with 56% reporting they thought not eating enough F&V would cause cancer. Understanding what motivates and prevents people from consuming F&V is important for developing effective health promotion programs. Similar to previous surveys, there has been little shift in F&V consumption. Social marketing campaigns have been shown to improve health-related behaviours, and this study may assist in identifying audience segmentation for better targeted

Non-occupational physical activity levels of shift workers compared with non-shift workers.

Science.gov (United States)

Loef, Bette; Hulsegge, Gerben; Wendel-Vos, G C Wanda; Verschuren, W M Monique; Vermeulen, Roel C H; Bakker, Marije F; van der Beek, Allard J; Proper, Karin I

2017-05-01

Lack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between shift workers and non-shift workers. Furthermore, exposure-response relationships for frequency of night shifts and years of shift work regarding non-occupational PA levels were studied. Data of 5980 non-shift workers and 532 shift workers from the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) were used in these cross-sectional analyses. Time spent (hours/week) in different PA types (walking/cycling/exercise/chores) and intensities (moderate/vigorous) were calculated based on self-reported PA. Furthermore, sports were operationalised as: playing sports (no/yes), individual versus non-individual sports, and non-vigorous-intensity versus vigorous-intensity sports. PA levels were compared between shift workers and non-shift workers using Generalized Estimating Equations and logistic regression. Shift workers reported spending more time walking than non-shift workers (B=2.3 (95% CI 1.2 to 3.4)), but shift work was not associated with other PA types and any of the sports activities. Shift workers who worked 1-4 night shifts/month (B=2.4 (95% CI 0.6 to 4.3)) and ≥5 night shifts/month (B=3.7 (95% CI 1.8 to 5.6)) spent more time walking than non-shift workers. No exposure-response relationships were found between years of shift work and PA levels. Shift workers spent more time walking than non-shift workers, but we observed no differences in other non-occupational PA levels. To better understand if and how PA plays a role in the negative health consequences of shift work, our findings need to be confirmed in future studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Using Linear and Non-Linear Temporal Adjustments to Align Multiple Phenology Curves, Making Vegetation Status and Health Directly Comparable

Science.gov (United States)

Hargrove, W. W.; Norman, S. P.; Kumar, J.; Hoffman, F. M.

2017-12-01

National-scale polar analysis of MODIS NDVI allows quantification of degree of seasonality expressed by local vegetation, and also selects the most optimum start/end of a local "phenological year" that is empirically customized for the vegetation that is growing at each location. Interannual differences in timing of phenology make direct comparisons of vegetation health and performance between years difficult, whether at the same or different locations. By "sliding" the two phenologies in time using a Procrustean linear time shift, any particular phenological event or "completion milestone" can be synchronized, allowing direct comparison of differences in timing of other remaining milestones. Going beyond a simple linear translation, time can be "rubber-sheeted," compressed or dilated. Considering one phenology curve to be a reference, the second phenology can be "rubber-sheeted" to fit that baseline as well as possible by stretching or shrinking time to match multiple control points, which can be any recognizable phenological events. Similar to "rubber sheeting" to georectify a map inside a GIS, rubber sheeting a phenology curve also yields a warping signature that shows at every time and every location how many days the adjusted phenology is ahead or behind the phenological development of the reference vegetation. Using such temporal methods to "adjust" phenologies may help to quantify vegetation impacts from frost, drought, wildfire, insects and diseases by permitting the most commensurate quantitative comparisons with unaffected vegetation.

How light competition between plants affects trait optimization and vegetation-atmosphere feedbacks

NARCIS (Netherlands)

van Loon, M.P.

2016-01-01

How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation

The oral bioavailability of nitrate from vegetables investigated in healthy volunteers

NARCIS (Netherlands)

Lambers AC; Kortboyer JM; Schothorst RC; Sips AJAM; Cleven RFMJ; Meulenbelt J; VIC; LBM; ARO; LAC

2000-01-01

The major source of human nitrate exposure comes from vegetables. Several studies were performed to estimate the total daily dietary nitrate intake based on the nitrate contents of food and drinking water. However, only nitrate that is absorbed from the gastro-intestinal tract may contribute to

The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

Science.gov (United States)

Ritson, Jonathan P.; Brazier, Richard E.; Graham, Nigel J. D.; Freeman, Chris; Templeton, Michael R.; Clark, Joanna M.

2017-06-01

Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.

Satellite-Based Assessment of the spatial extent of Aquatic Vegetation in Lake Victoria

Science.gov (United States)

Clark, W.; Aligeti, N.; Jeyaprakash, T.; Martins, M.; Stodghill, J.; Winstanley, H.

2011-12-01

Lake Victoria in Africa is the second largest freshwater lake in the world and is known for its abundance of aquatic wildlife. In particular over 200 different fish species are caught and sold by local fisherman. The lake is a major contributor to the local economy as a corridor of transportation, source of drinking water, and source of hydropower. However, the invasion of aquatic vegetation such as water hyacinth in the lake has disrupted each of these markets. Aquatic vegetation now covers a substantial area of the coastline blocking waterways, disrupting hydropower, hindering the collection of drinking water and decreasing the profitability of fishing. The vegetation serves as a habitat for disease carrying mosquitoes as well as snakes and snails that spread the parasitic disease bilharzia. The current control measures of invasive aquatic vegetation rely on biological, chemical and mechanical control. The objective of this study was to utilize remote sensing to map aquatic vegetation within Lake Victoria from 2000 to 2011. MODIS, Landsat 4-5TM, and Landsat 7-ETM imagery was employed to perform change detections in vegetation and identify the extent of aquatic vegetation throughout the years. The efficiency of containment efforts were evaluated and ideal time for application of such efforts were suggested. A methodology for aquatic vegetation surveillance was created. The results of this project were presented as a workshop to the Lake Victoria Fisheries Organization, SERVIR, and other partner organizations. The workshop provided instruction into the use of NASA and other satellite derived products. Time series animations of the spatial extent of aquatic vegetation within the lake were created. By identifying seasons of decreased aquatic vegetation, ideal times to employ control efforts were identified. SERVIR will subsequently utilize the methodologies and mapping results of this study to develop operational aquatic vegetation surveillance for Lake Victoria.

miRNA control of vegetative phase change in trees.

Directory of Open Access Journals (Sweden)

Jia-Wei Wang

2011-02-01

Full Text Available After germination, plants enter juvenile vegetative phase and then transition to an adult vegetative phase before producing reproductive structures. The character and timing of the juvenile-to-adult transition vary widely between species. In annual plants, this transition occurs soon after germination and usually involves relatively minor morphological changes, whereas in trees and other perennial woody plants it occurs after months or years and can involve major changes in shoot architecture. Whether this transition is controlled by the same mechanism in annual and perennial plants is unknown. In the annual forb Arabidopsis thaliana and in maize (Zea mays, vegetative phase change is controlled by the sequential activity of microRNAs miR156 and miR172. miR156 is highly abundant in seedlings and decreases during the juvenile-to-adult transition, while miR172 has an opposite expression pattern. We observed similar changes in the expression of these genes in woody species with highly differentiated, well-characterized juvenile and adult phases (Acacia confusa, Acacia colei, Eucalyptus globulus, Hedera helix, Quercus acutissima, as well as in the tree Populus x canadensis, where vegetative phase change is marked by relatively minor changes in leaf morphology and internode length. Overexpression of miR156 in transgenic P. x canadensis reduced the expression of miR156-targeted SPL genes and miR172, and it drastically prolonged the juvenile phase. Our results indicate that miR156 is an evolutionarily conserved regulator of vegetative phase change in both annual herbaceous plants and perennial trees.

European Vegetation Archive (EVA)

NARCIS (Netherlands)

Chytrý, Milan; Hennekens, S.M.; Jiménez-Alfaro, Borja; Schaminée, J.H.J.; Haveman, Rense; Janssen, J.A.M.

2016-01-01

The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and

Object-based vegetation classification with high resolution remote sensing imagery

Science.gov (United States)

Yu, Qian

Vegetation species are valuable indicators to understand the earth system. Information from mapping of vegetation species and community distribution at large scales provides important insight for studying the phenological (growth) cycles of vegetation and plant physiology. Such information plays an important role in land process modeling including climate, ecosystem and hydrological models. The rapidly growing remote sensing technology has increased its potential in vegetation species mapping. However, extracting information at a species level is still a challenging research topic. I proposed an effective method for extracting vegetation species distribution from remotely sensed data and investigated some ways for accuracy improvement. The study consists of three phases. Firstly, a statistical analysis was conducted to explore the spatial variation and class separability of vegetation as a function of image scale. This analysis aimed to confirm that high resolution imagery contains the information on spatial vegetation variation and these species classes can be potentially separable. The second phase was a major effort in advancing classification by proposing a method for extracting vegetation species from high spatial resolution remote sensing data. The proposed classification employs an object-based approach that integrates GIS and remote sensing data and explores the usefulness of ancillary information. The whole process includes image segmentation, feature generation and selection, and nearest neighbor classification. The third phase introduces a spatial regression model for evaluating the mapping quality from the above vegetation classification results. The effects of six categories of sample characteristics on the classification uncertainty are examined: topography, sample membership, sample density, spatial composition characteristics, training reliability and sample object features. This evaluation analysis answered several interesting scientific questions

Vegetation in the Forsmark biotest basin, 1974-1986

International Nuclear Information System (INIS)

Renstroem, S.; Svensson, Roger; Wigren-Svensson, M.

1990-05-01

Since 1980, Forsmark Power Plants has discharged large amount of cooling water into the Biotest basin. In 1974, before the dam was constructed, and 1980 to 1986, the macrophytic algae and higher vegetation inside and around the basin has been investigated. The observed changes are mainly caused by the increased water temperature causing lack of ice cover during the winter, the embankment reducing the exposition, the heavy water stream through the basin and the reduced light transmission in the water. The macroscopic vegetation in the Biotest basin was originally distributed all over the lake, but is now mainly found in more shallow water. The deepest part, a passage from the input of the cooling water to the output, totally lack vegetation. The reason for this is a combination of the heavy stream, raised temperature and reduced light transmission. The total biomass of macroscopic vegetation in the basin has been reduced from c. 70 metric ton in 1980 to c. 27 ton in 1982 and 1986. Among the most important species, the production of Chara spp. and Potamogeton pectinatus have been strongly reduced, while Cladophora glomerata and Vaucheria sp. have increased. Especially for Vaucheria, the raised temperature has been of vital importance. Among other species, Tolypella nidifica first increased, but has now totally disappeared. Zannichellia palustris was the only phanerogam which increased all the time. It is Z. palustris var. major which stands for the increase, while Z. palustris var. repens has disappeared from the basin. The shore vegetation, mainly reeds, has expanded conspicuously. From 1974 to 1980, the shore vegetation was favoured by the reduced exposition caused by the embankment. Since then, the raised temperature and absence of ice cover have resulted in an accelerating expansion of mainly Phragmites communis. Scirpus tabernaemontani and S. maritimus were first increasing, but do not seem to be able to compete with Phragmites in the long run. (au)

Remotely sensed vegetation moisture as explanatory variable of Lyme borreliosis incidence

Science.gov (United States)

Barrios, J. M.; Verstraeten, W. W.; Maes, P.; Clement, J.; Aerts, J. M.; Farifteh, J.; Lagrou, K.; Van Ranst, M.; Coppin, P.

2012-08-01

The strong correlation between environmental conditions and abundance and spatial spread of the tick Ixodes ricinus is widely documented. I. ricinus is in Europe the main vector of the bacterium Borrelia burgdorferi, the pathogen causing Lyme borreliosis (LB). Humidity in vegetated systems is a major factor in tick ecology and its effects might translate into disease incidence in humans. Time series of two remotely sensed indices with sensitivity to vegetation greenness and moisture were tested as explanatory variables of LB incidence. Wavelet-based multiresolution analysis allowed the examination of these signals at different temporal scales in study sites in Belgium, where increases in LB incidence were reported in recent years. The analysis showed the potential of the tested indices for disease monitoring, the usefulness of analyzing the signal in different time frames and the importance of local characteristics of the study area for the selection of the vegetation index.

Vegetation component of geothermal EIS studies: Introduced plants, ecosystem stability, and geothermal development

International Nuclear Information System (INIS)

1994-10-01

This paper contributes new information about the impacts from introduced plant invasions on the native Hawaiian vegetation as consequences of land disturbance and geothermal development activities. In this regard, most geothermal development is expected to act as another recurring source of physical disturbance which favors the spread and maintenance of introduced organisms throughout the region. Where geothermal exploration and development activities extend beyond existing agricultural and residential development, they will become the initial or sole source of disturbance to the naturalized vegetation of the area. Kilauea has a unique ecosystem adapted to the dynamics of a volcanically active landscape. The characteristics of this ecosystem need to be realized in order to understand the major threats to the ecosystem and to evaluate the effects of and mitigation for geothermal development in Puna. The native Puna vegetation is well adapted to disturbances associated with volcanic eruption, but it is ill-adapted to compete with alien plant species in secondary disturbances produced by human activities. Introduced plant and animal species have become a major threat to the continued presence of the native biota in the Puna region of reference

Vegetation component of geothermal EIS studies: Introduced plants, ecosystem stability, and geothermal development

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-10-01

This paper contributes new information about the impacts from introduced plant invasions on the native Hawaiian vegetation as consequences of land disturbance and geothermal development activities. In this regard, most geothermal development is expected to act as another recurring source of physical disturbance which favors the spread and maintenance of introduced organisms throughout the region. Where geothermal exploration and development activities extend beyond existing agricultural and residential development, they will become the initial or sole source of disturbance to the naturalized vegetation of the area. Kilauea has a unique ecosystem adapted to the dynamics of a volcanically active landscape. The characteristics of this ecosystem need to be realized in order to understand the major threats to the ecosystem and to evaluate the effects of and mitigation for geothermal development in Puna. The native Puna vegetation is well adapted to disturbances associated with volcanic eruption, but it is ill-adapted to compete with alien plant species in secondary disturbances produced by human activities. Introduced plant and animal species have become a major threat to the continued presence of the native biota in the Puna region of reference.

Multi-scale associations between vegetation cover and woodland bird communities across a large agricultural region.

Directory of Open Access Journals (Sweden)

Karen Ikin

Full Text Available Improving biodiversity conservation in fragmented agricultural landscapes has become an important global issue. Vegetation at the patch and landscape-scale is important for species occupancy and diversity, yet few previous studies have explored multi-scale associations between vegetation and community assemblages. Here, we investigated how patch and landscape-scale vegetation cover structure woodland bird communities. We asked: (1 How is the bird community associated with the vegetation structure of woodland patches and the amount of vegetation cover in the surrounding landscape? (2 Do species of conservation concern respond to woodland vegetation structure and surrounding vegetation cover differently to other species in the community? And (3 Can the relationships between the bird community and the woodland vegetation structure and surrounding vegetation cover be explained by the ecological traits of the species comprising the bird community? We studied 103 woodland patches (0.5 - 53.8 ha over two time periods across a large (6,800 km(2 agricultural region in southeastern Australia. We found that both patch vegetation and surrounding woody vegetation cover were important for structuring the bird community, and that these relationships were consistent over time. In particular, the occurrence of mistletoe within the patches and high values of woody vegetation cover within 1,000 ha and 10,000 ha were important, especially for bird species of conservation concern. We found that the majority of these species displayed similar, positive responses to patch and landscape vegetation attributes. We also found that these relationships were related to the foraging and nesting traits of the bird community. Our findings suggest that management strategies to increase both remnant vegetation quality and the cover of surrounding woody vegetation in fragmented agricultural landscapes may lead to improved conservation of bird communities.

Children and vegetables: strategies to increase children’s liking and intake of vegetables

NARCIS (Netherlands)

Wild, de V.W.T.

2015-01-01

Background and aim

Children’s vegetable intake is far below that recommended. Despite increased awareness of the importance of vegetable consumption for health, it remains challenging to improve children’s vegetable intake. Since food preferences are central to

Blue and red shifted temperature dependence of implicit phonon shifts in graphene

Science.gov (United States)

Mann, Sarita; Jindal, V. K.

2017-07-01

We have calculated the implicit shift for various modes of frequency in a pure graphene sheet. Thermal expansion and Grüneisen parameter which are required for implicit shift calculation have already been studied and reported. For this calculation, phonon frequencies are obtained using force constants derived from dynamical matrix calculated using VASP code where the density functional perturbation theory (DFPT) is used in interface with phonopy software. The implicit phonon shift shows an unusual behavior as compared to the bulk materials. The frequency shift is large negative (red shift) for ZA and ZO modes and the value of negative shift increases with increase in temperature. On the other hand, blue shift arises for all other longitudinal and transverse modes with a similar trend of increase with increase in temperature. The q dependence of phonon shifts has also been studied. Such simultaneous red and blue shifts in transverse or out plane modes and surface modes, respectively leads to speculation of surface softening in out of plane direction in preference to surface melting.

The role of water availability in controlling coupled vegetation-atmosphere dynamics

Science.gov (United States)

Scanlon, Todd Michael

This work examines how water availability affects vegetation structure and vegetation-atmosphere exchange of water, carbon, and energy for a savanna ecosystem. The study site is the Kalahari Transect (KT), in southern Africa, which follows a north-south decline in mean annual rainfall from ˜1600 mm/yr to ˜250 mm/yr between the latitudes 12°--26°S. Eddy covariance (EC) flux measurements taken over a time frame of 1--9 days at four sites along the transect during the wet (growing) season revealed that the ecosystem water use efficiency for the sites, defined as the ratio of net carbon flux to evapotranspiration, decreased with increasing mean annual rainfall. EC data were used to parameterize a large eddy simulation model, which was applied over a heterogeneous remotely-sensed surface. Water availability for the vegetation was found to affect the relative controls (structural vs. meteorological) on the spatial distribution of vegetation fluxes. When the spatial distribution of vapor pressure deficit, D, was most predictable (i.e. non water-limiting conditions) it was unimportant in shaping the distribution of the vegetation fluxes, while at times when D was least predictable (i.e. water-limiting conditions) it was most important. This observation is explained by the relative degree of vegetation-atmosphere coupling and the complexity of the non-local effects on D , both of which are dependent upon water availability. Based upon the differing ways in which trees and grass respond to interannual variability in rainfall, a new method was developed to estimate fractional tree, grass, and bare soil cover from a synthesis of satellite and ground-based data. This method was applied to the KT where it was found that tree fractional cover declines with mean annual rainfall, while grass fractional cover peaks near the middle of the gradient. A soil moisture model applied to this data indicated a shift from nutrient- to water-limitation from the mesic to arid portions of

Formation of banded vegetation patterns resulted from interactions between sediment deposition and vegetation growth.

Science.gov (United States)

Huang, Tousheng; Zhang, Huayong; Dai, Liming; Cong, Xuebing; Ma, Shengnan

2018-03-01

This research investigates the formation of banded vegetation patterns on hillslopes affected by interactions between sediment deposition and vegetation growth. The following two perspectives in the formation of these patterns are taken into consideration: (a) increased sediment deposition from plant interception, and (b) reduced plant biomass caused by sediment accumulation. A spatial model is proposed to describe how the interactions between sediment deposition and vegetation growth promote self-organization of banded vegetation patterns. Based on theoretical and numerical analyses of the proposed spatial model, vegetation bands can result from a Turing instability mechanism. The banded vegetation patterns obtained in this research resemble patterns reported in the literature. Moreover, measured by sediment dynamics, the variation of hillslope landform can be described. The model predicts how treads on hillslopes evolve with the banded patterns. Thus, we provide a quantitative interpretation for coevolution of vegetation patterns and landforms under effects of sediment redistribution. Copyright © 2018. Published by Elsevier Masson SAS.

Fruit and vegetable consumption and risk of overall mortality and gastrointestinal cancer

NARCIS (Netherlands)

Leenders, M.B.

2014-01-01

Fruits and vegetables are considered a major part of a healthy diet, because consumption increases satiety and reduces total energy intake by replacing more energy dense foods. In addition, they contain dietary fiber, vitamins, minerals and thousands of naturally occurring biologically active

Polarimetric scattering model for estimation of above ground biomass of multilayer vegetation using ALOS-PALSAR quad-pol data

Science.gov (United States)

Sai Bharadwaj, P.; Kumar, Shashi; Kushwaha, S. P. S.; Bijker, Wietske

Forests are important biomes covering a major part of the vegetation on the Earth, and as such account for seventy percent of the carbon present in living beings. The value of a forest's above ground biomass (AGB) is considered as an important parameter for the estimation of global carbon content. In the present study, the quad-pol ALOS-PALSAR data was used for the estimation of AGB for the Dudhwa National Park, India. For this purpose, polarimetric decomposition components and an Extended Water Cloud Model (EWCM) were used. The PolSAR data orientation angle shifts were compensated for before the polarimetric decomposition. The scattering components obtained from the polarimetric decomposition were used in the Water Cloud Model (WCM). The WCM was extended for higher order interactions like double bounce scattering. The parameters of the EWCM were retrieved using the field measurements and the decomposition components. Finally, the relationship between the estimated AGB and measured AGB was assessed. The coefficient of determination (R2) and root mean square error (RMSE) were 0.4341 and 119 t/ha respectively.

Genome Dynamics of Hybrid Saccharomyces cerevisiae During Vegetative and Meiotic Divisions

Directory of Open Access Journals (Sweden)

Abhishek Dutta

2017-11-01

Full Text Available Mutation and recombination are the major sources of genetic diversity in all organisms. In the baker’s yeast, all mutation rate estimates are in homozygous background. We determined the extent of genetic change through mutation and loss of heterozygosity (LOH in a heterozygous Saccharomyces cerevisiae genome during successive vegetative and meiotic divisions. We measured genome-wide LOH and base mutation rates during vegetative and meiotic divisions in a hybrid (S288c/YJM789 S. cerevisiae strain. The S288c/YJM789 hybrid showed nearly complete reduction in heterozygosity within 31 generations of meioses and improved spore viability. LOH in the meiotic lines was driven primarily by the mating of spores within the tetrad. The S288c/YJM789 hybrid lines propagated vegetatively for the same duration as the meiotic lines, showed variable LOH (from 2 to 3% and up to 35%. Two of the vegetative lines with extensive LOH showed frequent and large internal LOH tracts that suggest a high frequency of recombination repair. These results suggest significant LOH can occur in the S288c/YJM789 hybrid during vegetative propagation presumably due to return to growth events. The average base substitution rates for the vegetative lines (1.82 × 10−10 per base per division and the meiotic lines (1.22 × 10−10 per base per division are the first genome-wide mutation rate estimates for a hybrid yeast. This study therefore provides a novel context for the analysis of mutation rates (especially in the context of detecting LOH during vegetative divisions, compared to previous mutation accumulation studies in yeast that used homozygous backgrounds.

OpenShift Workshop

CERN Multimedia

CERN. Geneva; Rodriguez Peon, Alberto

2017-01-01

Workshop to introduce developers to the OpenShift platform available at CERN. Several use cases will be shown, including deploying an existing application into OpenShift. We expect attendees to realize about OpenShift features and general architecture of the service.

Trait-based diversification shifts reflect differential extinction among fossil taxa.

Science.gov (United States)

Wagner, Peter J; Estabrook, George F

2014-11-18

Evolution provides many cases of apparent shifts in diversification associated with particular anatomical traits. Three general models connect these patterns to anatomical evolution: (i) elevated net extinction of taxa bearing particular traits, (ii) elevated net speciation of taxa bearing particular traits, and (iii) elevated evolvability expanding the range of anatomies available to some species. Trait-based diversification shifts predict elevated hierarchical stratigraphic compatibility (i.e., primitive→derived→highly derived sequences) among pairs of anatomical characters. The three specific models further predict (i) early loss of diversity for taxa retaining primitive conditions (elevated net extinction), (ii) increased diversification among later members of a clade (elevated net speciation), and (iii) increased disparity among later members in a clade (elevated evolvability). Analyses of 319 anatomical and stratigraphic datasets for fossil species and genera show that hierarchical stratigraphic compatibility exceeds the expectations of trait-independent diversification in the vast majority of cases, which was expected if trait-dependent diversification shifts are common. Excess hierarchical stratigraphic compatibility correlates with early loss of diversity for groups retaining primitive conditions rather than delayed bursts of diversity or disparity across entire clades. Cambrian clades (predominantly trilobites) alone fit null expectations well. However, it is not clear whether evolution was unusual among Cambrian taxa or only early trilobites. At least among post-Cambrian taxa, these results implicate models, such as competition and extinction selectivity/resistance, as major drivers of trait-based diversification shifts at the species and genus levels while contradicting the predictions of elevated net speciation and elevated evolvability models.

Operator performance on the night shift: phases 1 and 2

International Nuclear Information System (INIS)

Morisseau, Dolores; Beere, Barnaby; Collier, Steve

1999-04-01

The objective of the project on operator performance on the night shift is to determine the effects of circadian rhythms on higher order cognitive processes. The project had two preliminary phases. Subjects were operators from the Halden Boiling Water Reactor, (Phase 1: 7 male operators and shift leaders, aged 26 to 35; Phase 2: 8 male operators and shift leaders, aged 26 to 53). The majority of the operators were the same for both studies. The preliminary work established that Norwegian operators' circadian rhythms fall within universal population norms and, thus, they are suitable subjects for such experiments. During Phase 1, two self-assessment instruments, the Stanford Sleepiness Scale (SSS) and the Global Vigour and Affect Scale (GVA), were administered every hour on all three shifts at the reactor. During Phase 2, three tests from the Walter Reed Performance Assessment Battery were administered at the beginning, middle, and end of each of the three shifts at the reactor. The tests (Serial Add-Subtract, Two-Column Addition, and Logical Reasoning) were administered using a hand-held computer. Both phases were conducted during regular work shifts for one complete shift rota (six weeks). ANOVA with two repeated measures showed that self-reported sleepiness on the night shift, sleepiness with respect to hours into the shift, and the interaction between them all reached statistical significance at p<.001. Data analyses (ANOVA) from Phase 2 indicate that the main effect of SHIFTNO (morning, afternoon, evening) on response times was significant (p<.002); the interaction between SHIFTNO and TINSHIFT (hours into shift) was also significant (p<.009). None of the effects on correctness of response was significant (Phase 2). While correctness of response was not significant for routine cognitive measures, the significant, progressive slowing of response times on the night shift reinforces the concern for possible performance decrements on the night shift. Thus, it

Availability of, access to and consumption of fruits and vegetables in a peri-urban area in KwaZulu-Natal, South Africa.

Science.gov (United States)

Faber, Mieke; Laubscher, Ria; Laurie, Sunette

2013-07-01

Availability and consumption of fruits and vegetables were assessed in peri-urban households in KwaZulu-Natal Province, South Africa. Caregivers of 400 randomly selected grade 6 and 7 learners were interviewed using a questionnaire that included unquantified food frequency questions. Using a repeated 24-h dietary recall, dietary intake was quantified for learners, caregivers and 2- to 5-year-old children in the household. Usual household fruit and vegetable consumption was expressed over three Living Standard Measure (LSM) categories. Average per capita intake of fruit and/or vegetables was 99 g for 2- to 5-year-old children and 124 g for caregivers. For consumers, fruits and/or vegetables contributed towards total dietary intake of fibre (16-21%), calcium (13-21%), vitamin A (27-31%) and vitamin C (47-62%). For households not consuming fruits (n = 297) and vegetables (n = 178) daily, cost was the major constraint (≥75%). Of all households, 52% had fruit trees and 25% had a vegetable garden. Animals destroying vegetables was the major constraint to 59% of vegetable growers. Household consumption of fruits and vegetables increased over the LSM categories. Caregivers in the higher LSM group more likely used printed material for information on healthy eating, had fruit trees, were confident about vegetable gardening and sold some of their produce. To enable peri-urban populations of low socio-economic status to consume more frequently a bigger variety of fruits and vegetables, the cost of purchasing these food items needs to be addressed by government and business sector. Households should further receive support to overcome constraints which hamper the success of home gardens. © 2011 John Wiley & Sons Ltd.

Irradiation of dehydrated vegetables

International Nuclear Information System (INIS)

Esterhuyse, A; Esterhuizen, T.

1985-01-01

The reason for radurization was to decreased the microbial count of dehydrated vegetables. The average absorbed irradiation dose range between 2kGy and 15kGy. The product catagories include a) Green vegetables b) White vegetables c) Powders of a) and b). The microbiological aspects were: Declining curves for the different products of T.P.C., Coliforms, E. Coli, Stap. areus, Yeast + Mold at different doses. The organoleptical aspects were: change in taste, flavour, texture, colour and moisture. The aim is the marketing of irradiated dehydrated vegetables national and international basis

Contributors to shift work tolerance in South Korean nurses working rotating shift.

Science.gov (United States)

Jung, Hye-Sun; Lee, Bokim

2015-05-01

Shift workers have rapidly increased in South Korea; however, there is no published research exploring shift work tolerance among South Korean workers. This study aimed to investigate factors related to shift work tolerance in South Korean nurses. The sample comprised of 660 nurses who worked shifts in a large hospital in South Korea. A structured questionnaire included following comprehensive variables: demographic (age and number of children), individual (morningness and self-esteem), psychosocial (social support and job stress), lifestyle (alcohol consumption, physical activity, and BMI), and working condition factors (number of night shifts and working hours). Shift work tolerance was measured in terms of insomnia, fatigue, and depression. The results of hierarchical regressions indicate that all variables, except for three, number of children, BMI, and working hours, were related to at least one of the symptoms associated with shift work tolerance. Based on these results, we offer some practical implications to help improve shift work tolerance of workers. Copyright © 2014 Elsevier Inc. All rights reserved.

The hudiara drain wastewater effect on the distribution of surrounding herbaceous vegetation

Energy Technology Data Exchange (ETDEWEB)

Shah, F R; Ahmad, N; Zahid, D M; Masood, K R; Ahmad, S.S., E-mail: dinmuhammadzahid@bzu.edu.p

2010-06-15

In this study, phytosociological survey using Braun-Blanquet's approach was undertaken to investigate the Hudiara drain wastewater influence on the surrounding vegetation. A total of 99 quadrats were laid to identify the plant species and altogether 66 species were recorded. Multivariate analysis of vegetation data (using CANOCO 4.5. software) classified the vegetation into two major communities including Cynodon dactylon, Boerhaavia diffusa, Parthenium hysterphorus and Xanthium strumarium groups. The presence of these species designated the area as waste land strongly supporting the growth of such species. The pattern of floral diversity was also not uniform and exhibited considerable variation. Canonical Correspondence Analysis revealed that the distribution of vegetation has correlation with environmental variables, but their role in the grouping of species remained non significant. However, soil EC played some role in the grouping of Stellaria media and Fagonia cretic. Similarly, some species viz., Ricinus communis, Boerhaavia diffusa and Phragmites karka showed a correlation with Fe and Cr respectively, suggesting Phragmites karka as a suitable candidate for chromium contaminated sites. (author)

The hudiara drain wastewater effect on the distribution of surrounding herbaceous vegetation

International Nuclear Information System (INIS)

Shah, F.R.; Ahmad, N.; Zahid, D.M.; Masood, K.R.; Ahmad, S.S.

2010-01-01

In this study, phytosociological survey using Braun-Blanquet's approach was undertaken to investigate the Hudiara drain wastewater influence on the surrounding vegetation. A total of 99 quadrats were laid to identify the plant species and altogether 66 species were recorded. Multivariate analysis of vegetation data (using CANOCO 4.5. software) classified the vegetation into two major communities including Cynodon dactylon, Boerhaavia diffusa, Parthenium hysterphorus and Xanthium strumarium groups. The presence of these species designated the area as waste land strongly supporting the growth of such species. The pattern of floral diversity was also not uniform and exhibited considerable variation. Canonical Correspondence Analysis revealed that the distribution of vegetation has correlation with environmental variables, but their role in the grouping of species remained non significant. However, soil EC played some role in the grouping of Stellaria media and Fagonia cretic. Similarly, some species viz., Ricinus communis, Boerhaavia diffusa and Phragmites karka showed a correlation with Fe and Cr respectively, suggesting Phragmites karka as a suitable candidate for chromium contaminated sites. (author)

Can riparian vegetation shade mitigate the expected rise in stream temperatures due to climate change during heat waves in a human-impacted pre-alpine river?

Directory of Open Access Journals (Sweden)

H. Trimmel

2018-01-01

Full Text Available Global warming has already affected European rivers and their aquatic biota, and climate models predict an increase of temperature in central Europe over all seasons. We simulated the influence of expected changes in heat wave intensity during the 21st century on water temperatures of a heavily impacted pre-alpine Austrian river and analysed future mitigating effects of riparian vegetation shade on radiant and turbulent energy fluxes using the deterministic Heat Source model. Modelled stream water temperature increased less than 1.5 °C within the first half of the century. Until 2100, a more significant increase of around 3 °C in minimum, maximum and mean stream temperatures was predicted for a 20-year return period heat event. The result showed clearly that in a highly altered river system riparian vegetation was not able to fully mitigate the predicted temperature rise caused by climate change but would be able to reduce water temperature by 1 to 2 °C. The removal of riparian vegetation amplified stream temperature increases. Maximum stream temperatures could increase by more than 4 °C even in annual heat events. Such a dramatic water temperature shift of some degrees, especially in summer, would indicate a total shift of aquatic biodiversity. The results demonstrate that effective river restoration and mitigation require re-establishing riparian vegetation and emphasize the importance of land–water interfaces and their ecological functioning in aquatic environments.

Can riparian vegetation shade mitigate the expected rise in stream temperatures due to climate change during heat waves in a human-impacted pre-alpine river?

Science.gov (United States)

Trimmel, Heidelinde; Weihs, Philipp; Leidinger, David; Formayer, Herbert; Kalny, Gerda; Melcher, Andreas

2018-01-01

Global warming has already affected European rivers and their aquatic biota, and climate models predict an increase of temperature in central Europe over all seasons. We simulated the influence of expected changes in heat wave intensity during the 21st century on water temperatures of a heavily impacted pre-alpine Austrian river and analysed future mitigating effects of riparian vegetation shade on radiant and turbulent energy fluxes using the deterministic Heat Source model. Modelled stream water temperature increased less than 1.5 °C within the first half of the century. Until 2100, a more significant increase of around 3 °C in minimum, maximum and mean stream temperatures was predicted for a 20-year return period heat event. The result showed clearly that in a highly altered river system riparian vegetation was not able to fully mitigate the predicted temperature rise caused by climate change but would be able to reduce water temperature by 1 to 2 °C. The removal of riparian vegetation amplified stream temperature increases. Maximum stream temperatures could increase by more than 4 °C even in annual heat events. Such a dramatic water temperature shift of some degrees, especially in summer, would indicate a total shift of aquatic biodiversity. The results demonstrate that effective river restoration and mitigation require re-establishing riparian vegetation and emphasize the importance of land-water interfaces and their ecological functioning in aquatic environments.

Vegetable Genetic Resources in China

Directory of Open Access Journals (Sweden)

Haiping WANG

2018-03-01

Full Text Available China is recognized as an important region for plant biodiversity based on its vast and historical collection of vegetable germplasm. The aim of this review is to describe the exploration status of vegetable genetic resources in China, including their collection, preservation, evaluation, and utilization. China has established a number of national-level vegetable genetic resources preservation units, including the National Mid-term Genebank for Vegetable Germplasm Resources, the National Germplasm Repository for Vegetatively-Propagated Vegetables, and the National Germplasm Repository for Aquatic Vegetables. In 2015, at least 36 000 accessions were collected and preserved in these units. In the past decade, 44 descriptors and data standards for different species have been published, and most accessions have been evaluated for screening the germplasms for specific important traits such as morphological characteristics, disease resistance, pest resistance, and stress tolerance. Moreover, the genetic diversity and evolution of some vegetable germplasms have been evaluated at the molecular level. Recently, more than 1 000 accessions were distributed to researchers and breeders each year by various means for vegetable research and production. However, additional wild-relative and abroad germplasms from other regions need to be collected and preserved in the units to expand genetic diversity. Furthermore, there is a need to utilize advanced techniques to better understand the background and genetic diversity of a wide range of vegetable genetic resources. This review will provide agricultural scientists’ insights into the genetic diversity in China and provide information on the distribution and potential utilization of these valuable genetic resources. Keywords: vegetable, genetic resource, preservation, evaluation, utilization

Modelling the Congo basin ecosystems with a dynamic vegetation model

Science.gov (United States)

Dury, Marie; Hambuckers, Alain; Trolliet, Franck; Huynen, Marie-Claude; Haineaux, Damien; Fontaine, Corentin M.; Fayolle, Adeline; François, Louis

2014-05-01

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are interesting alternatives to study those regions even if the lack of data often prevents sharp calibration and validation of the model projections. Dynamic vegetation models (DVMs) are process-based models that simulate shifts in potential vegetation and its associated biogeochemical and hydrological cycles in response to climate. Initially run at the global scale, DVMs can be run at any spatial scale provided that climate and soil data are available. In the framework of the BIOSERF project ("Sustainability of tropical forest biodiversity and services under climate and human pressure"), we use and adapt the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) to study the Congo basin vegetation dynamics. The field campaigns have notably allowed the refinement of the vegetation representation from plant functional types (PFTs) to individual species through the collection of parameters such as the specific leaf area or the leaf C:N ratio of common tropical tree species and the location of their present-day occurrences from literature and available database. Here, we test the model ability to reproduce the present spatial and temporal variations of carbon stocks (e.g. biomass, soil carbon) and fluxes (e.g. gross and net primary productivities (GPP and NPP), net ecosystem production (NEP)) as well as the observed distribution of the studied species over the Congo basin. In the lack of abundant and long-term measurements, we compare model results with time series of remote sensing products (e.g. vegetation leaf area index (LAI), GPP and NPP). Several sensitivity tests are presented: we assess consecutively the impacts of the level at which the vegetation is simulated (PFTs or species), the spatial resolution and the initial land

Monitoring vegetation dynamics with medium resolution MODIS-EVI time series at sub-regional scale in southern Africa

Science.gov (United States)

Dubovyk, Olena; Landmann, Tobias; Erasmus, Barend F. N.; Tewes, Andreas; Schellberg, Jürgen

2015-06-01

Currently there is a lack of knowledge on spatio-temporal patterns of land surface dynamics at medium spatial scale in southern Africa, even though this information is essential for better understanding of ecosystem response to climatic variability and human-induced land transformations. In this study, we analysed vegetation dynamics across a large area in southern Africa using the 14-years (2000-2013) of medium spatial resolution (250 m) MODIS-EVI time-series data. Specifically, we investigated temporal changes in the time series of key phenometrics including overall greenness, peak and timing of annual greenness over the monitoring period and study region. In order to specifically capture spatial and per pixel vegetation changes over time, we calculated trends in these phenometrics using a robust trend analysis method. The results showed that interannual vegetation dynamics followed precipitation patterns with clearly differentiated seasonality. The earliest peak greenness during 2000-2013 occurred at the end of January in the year 2000 and the latest peak greenness was observed at the mid of March in 2012. Specifically spatial patterns of long-term vegetation trends allowed mapping areas of (i) decrease or increase in overall greenness, (ii) decrease or increase of peak greenness, and (iii) shifts in timing of occurrence of peak greenness over the 14-year monitoring period. The observed vegetation decline in the study area was mainly attributed to human-induced factors. The obtained information is useful to guide selection of field sites for detailed vegetation studies and land rehabilitation interventions and serve as an input for a range of land surface models.

Expert system application for prioritizing preventive actions for shift work: shift expert.

Science.gov (United States)

Esen, Hatice; Hatipoğlu, Tuğçen; Cihan, Ahmet; Fiğlali, Nilgün

2017-09-19

Shift patterns, work hours, work arrangements and worker motivations have increasingly become key factors for job performance. The main objective of this article is to design an expert system that identifies the negative effects of shift work and prioritizes mitigation efforts according to their importance in preventing these negative effects. The proposed expert system will be referred to as the shift expert. A thorough literature review is conducted to determine the effects of shift work on workers. Our work indicates that shift work is linked to demographic variables, sleepiness and fatigue, health and well-being, and social and domestic conditions. These parameters constitute the sections of a questionnaire designed to focus on 26 important issues related to shift work. The shift expert is then constructed to provide prevention advice at the individual and organizational levels, and it prioritizes this advice using a fuzzy analytic hierarchy process model, which considers comparison matrices provided by users during the prioritization process. An empirical study of 61 workers working on three rotating shifts is performed. After administering the questionnaires, the collected data are analyzed statistically, and then the shift expert produces individual and organizational recommendations for these workers.

Carbon accumulation in a permafrost polygon peatland: steady long-term rates in spite of shifts between dry and wet conditions.

Science.gov (United States)

Gao, Yang; Couwenberg, John

2015-02-01

Ice-wedge polygon peatlands contain a substantial part of the carbon stored in permafrost soils. However, little is known about their long-term carbon accumulation rates (CAR) in relation to shifts in vegetation and climate. We collected four peat profiles from one single polygon in NE Yakutia and cut them into contiguous 0.5 cm slices. Pollen density interpolation between AMS (14)C dated levels provided the time span contained in each of the sample slices, which--in combination with the volumetric carbon content--allowed for the reconstruction of CAR over decadal and centennial timescales. Vegetation representing dry palaeo-ridges and wet depressions was reconstructed with detailed micro- and macrofossil analysis. We found repeated shifts between wet and dry conditions during the past millennium. Dry ridges with associated permafrost growth originated during phases of (relatively) warm summer temperature and collapsed during relatively cold phases, illustrating the important role of vegetation and peat as intermediaries between ambient air temperature and the permafrost. The average long-term CAR across the four profiles was 10.6 ± 5.5 g C m(-2) yr(-1). Time-weighted mean CAR did not differ significantly between wet depression and dry ridge/hummock phases (10.6 ± 5.2 g C m(-2) yr(-1) and 10.3 ± 5.7 g C m(-2) yr(-1), respectively). Although we observed increased CAR in relation to warm shifts, we also found changes in the opposite direction and the highest CAR actually occurred during the Little Ice Age. In fact, CAR rather seems to be governed by strong internal feedback mechanisms and has roughly remained stable on centennial time scales. The absence of significant differences in CAR between dry ridge and wet depression phases suggests that recent warming and associated expansion of shrubs will not affect long-term rates of carbon burial in ice-wedge polygon peatlands. © 2014 John Wiley & Sons Ltd.

Eating breakfast, fruit and vegetable intake and their relation with happiness in college students.

Science.gov (United States)

Lesani, Azadeh; Mohammadpoorasl, Asghar; Javadi, Maryam; Esfeh, Jabiz Modaresi; Fakhari, Ali

2016-12-01

Nutrition plays a major role in physical and mental health. The aim of this study was to evaluate the relationships between happiness and fruit and vegetable intake as well as eating breakfast in students. In this cross-sectional web-based study, all students of Qazvin University of Medical Sciences in Iran who attended course classes were invited to participate in the study. Five hundred forty-one students filled out the web-based questionnaire which included questions related to measurement of happiness, breakfast, fruit and vegetable consumption and socio-economic and demographic information. Analysis of covariance was used to assess the relationship between happiness and breakfast, fruit and vegetable consumption by adjustments for covariates. Measure of happiness was positively associated with eating breakfast, number of meals eaten daily and the amount of fruit and vegetable consumption (P values were breakfast every day, more than 8 servings of fruit and vegetables daily, and had 3 meals in addition to 1-2 snacks per day had the highest happiness score. Healthier behavior pattern was associated with higher happiness scores among medical students.

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

Science.gov (United States)

Peng, Qiannan; Jiang, Shuaiming; Chen, Jieling; Ma, Chenchen; Huo, Dongxue; Shao, Yuyu; Zhang, Jiachao

2018-01-01

Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing tropical microbial

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

Directory of Open Access Journals (Sweden)

Qiannan Peng

2018-03-01

Full Text Available Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing

Regional vegetation dynamics and its response to climate change—a case study in the Tao River Basin in Northwestern China

International Nuclear Information System (INIS)

Li, Changbin; Yang, Linshan; Wang, Shuaibing; Yang, Wenjin; Zhu, Gaofeng; Qi, Jiaguo; Zou, Songbing; Zhang, Feng

2014-01-01

The 30-year normalized-difference vegetation index (NDVI) time series from AVHRR/MODIS satellite sensors was used in this study to assess the regional vegetation dynamic changes in the Tao River Basin, which cuts across the Eastern Tibetan Plateau (ETP) and the Southwestern Loess Plateau (SLP). First, principal component and correlation analyses were carried out to determine the key climatic variables driving ecological change in the region. Then, regression models were tested to correlate NDVI with the selected climatic variables to determine their predictive power. Finally, Sen’s slope method was used to determine how terrestrial vegetation has responded to regional climate change in the region. The results indicated an average winter season NDVI value of 0.14 in the ETP but only 0.04 in the SLP. Primarily driven by increasing temperature, vegetation growth has generally been enhanced since 1981; spring NDVI increased by 0.03 every 10 years in the ETP and 0.02 in the SLP. Further, results from trend analyses suggest vegetation growth in the ETP shifted to earlier-start and earlier-end dates, however in the SLP, the growing season has been extended with an earlier-start and later-end date. The precipitation threshold for vegetation germination, measured by the cumulative spring rainfall, was found to be 44 mm for both the ETP and SLP. (paper)

Implementing OpenShift

CERN Document Server

Miller, Adam

2013-01-01

A standard tutorial-based approach to using OpenShift and deploying custom or pre-built web applications to the OpenShift Online cloud.This book is for software developers and DevOps alike who are interested in learning how to use the OpenShift Platform-as-a-Service for developing and deploying applications, how the environment works on the back end, and how to deploy their very own open source Platform-as-a-Service based on the upstream OpenShift Origin project.

Heavy metals in green vegetables and soils from vegetable gardens ...

African Journals Online (AJOL)

Edible portions of five varieties of green vegetables, namely amaranth, chinese cabbage, cowpea leaves, leafy cabbage and pumpkin leaves, collected from several areas in Dar es Salaam, were analyzed for lead, cadmium, chromium, zinc, nickel and copper. Except for zinc, the levels of heavy metals in the vegetables ...

Impacts of the seasonal distribution of rainfall on vegetation productivity across the Sahel

Science.gov (United States)

Zhang, Wenmin; Brandt, Martin; Tong, Xiaoye; Tian, Qingjiu; Fensholt, Rasmus

2018-01-01

Climate change in drylands has caused alterations in the seasonal distribution of rainfall including increased heavy-rainfall events, longer dry spells, and a shifted timing of the wet season. Yet the aboveground net primary productivity (ANPP) in drylands is usually explained by annual-rainfall sums, disregarding the influence of the seasonal distribution of rainfall. This study tested the importance of rainfall metrics in the wet season (onset and cessation of the wet season, number of rainy days, rainfall intensity, number of consecutive dry days, and heavy-rainfall events) for growing season ANPP. We focused on the Sahel and northern Sudanian region (100-800 mm yr-1) and applied daily satellite-based rainfall estimates (CHIRPS v2.0) and growing-season-integrated normalized difference vegetation index (NDVI; MODIS) as a proxy for ANPP over the study period: 2001-2015. Growing season ANPP in the arid zone (100-300 mm yr-1) was found to be rather insensitive to variations in the seasonal-rainfall metrics, whereas vegetation in the semi-arid zone (300-700 mm yr-1) was significantly impacted by most metrics, especially by the number of rainy days and timing (onset and cessation) of the wet season. We analysed critical breakpoints for all metrics to test if vegetation response to changes in a given rainfall metric surpasses a threshold beyond which vegetation functioning is significantly altered. It was shown that growing season ANPP was particularly negatively impacted after > 14 consecutive dry days and that a rainfall intensity of ˜ 13 mm day-1 was detected for optimum growing season ANPP. We conclude that the number of rainy days and the timing of the wet season are seasonal-rainfall metrics that are decisive for favourable vegetation growth in the semi-arid Sahel and need to be considered when modelling primary productivity from rainfall in the drylands of the Sahel and elsewhere.

Effects of extended work shifts on employee fatigue, health, satisfaction, work/family balance, and patient safety.

Science.gov (United States)

Estryn-Béhar, Madeleine; Van der Heijden, Beatrice I J M

2012-01-01

12-hour shifts are quickly spreading in Europe. From our multivariate analysis concerning 25,924 European nurses, including twenty explanatory variables simultaneously, we found that work schedule itself is not a major determinant factor. Nurses aim to choose or accept night shifts or 12-hour shift in order to reduce their work/home conflicts, however, at the expense of the patient's safety, as well as their own health and safety. Therefore, it is important to develop measures, such as extended child care, association of nurses to the elaboration of their rota, 9- or 10-hour shifts in the afternoon, allowing naps during night shifts, and reduction of changing shifts with short notice. Work schedules must be organized in order to allow time for shift handover, social support and team building.

Association between community garden participation and fruit and vegetable consumption in rural Missouri.

Science.gov (United States)

Barnidge, Ellen K; Hipp, Pamela R; Estlund, Amy; Duggan, Kathleen; Barnhart, Kathryn J; Brownson, Ross C

2013-11-19

Fruit and vegetable consumption reduces chronic disease risk, yet the majority of Americans consume fewer than recommended. Inadequate access to fruits and vegetables is increasingly recognized as a significant contributor to low consumption of healthy foods. Emerging evidence shows the effectiveness of community gardens in increasing access to, and consumption of, fruits and vegetables. Two complementary studies explored the association of community garden participation and fruit and vegetable consumption in rural communities in Missouri. The first was with a convenience sample of participants in a rural community garden intervention who completed self-administered surveys. The second was a population-based survey conducted with a random sample of 1,000 residents in the intervention catchment area. Participation in a community garden was associated with higher fruit and vegetable consumption. The first study found that individuals who worked in a community garden at least once a week were more likely to report eating fruits and vegetables because of their community garden work (X² (125) = 7.78, p = .0088). Population-based survey results show that 5% of rural residents reported participating in a community garden. Those who reported community garden participation were more likely to report eating fruits 2 or more times per day and vegetables 3 or more times per day than those who did not report community garden participation, even after adjusting for covariates (Odds Ratio [OR] = 2.76, 95% Confidence Interval [CI] = 1.35 to 5.65). These complementary studies provide evidence that community gardens are a promising strategy for promoting fruit and vegetable consumption in rural communities.

Comparing heavy metals accumulation potential in natural vegetation and soil adjoining wastewater canal

International Nuclear Information System (INIS)

Aurangzeb, N.; Irshad, M.; Hussain, F.; Mahmood, Q.

2011-01-01

Heavy metal (HM) pollution of waters, soils and vegetation is a major ecological problem that needs to be investigated. The present study involved the collection of soil samples and natural vegetations (Tribilas terristris, Lepia nodiflora, Amaranthus viridis, Heliotropium euoropeum, Coronopis didymus, Cynodon ductylon, Chenopodium murale and Eclipta alba) from the vicinity of wastewater canal and subsequent analysis for their HM concentrations. Results showed that HM concentrations varied within the species of vegetation and type of metal analyzed. The order of vegetation for metal concentrations was A. viridis > E. alba > H. euoropeum > L. nodiflora > C. murale > C. didymus > C. ductylon > T. terristris. Metals prevailed in plants in the decreasing order of Fe > Mn > Zn > Pb > Cr > Cu > Cd, irrespective of the vegetation. Metal prevalence in soils was in the order of Fe > Mn > Cd > Cr > Pb > Zn > Cu. Samples near canal were found with higher level of Mn, Pb and Zn as compared to soil away from canal water. Distant sampling gave higher accumulation of Cd, Cr, Cu and Fe as compared to the soil nearby wastewater. The analyzed species of HM in the soils and plants may indicate the variability of their composition in wastewater. (author)

The physical environment and major plant communities of the Karoo National Park, South Africa

OpenAIRE

Francine Rubin; A.R. Palmer

1996-01-01

The major plant communities of the Karoo National Park are described using the methods of the Zurich-Montpellier school of phytosociology, to assist with the formulation of a management strategy for the park. The vegetation physiognomy consists of Montane Karoo grassy shrublands. Karoo grassy dwarf shrublands. Karoo succulent dwarf shrublands and riparian thicket. Steep elevation and precipitation gradients within the study area have a direct impact on gradients in the vegetation. High elevat...

Effectiveness of flavour nutrient learning and mere exposure as mechanisms to increase toddler's intake and preference for green vegetables.

Science.gov (United States)

de Wild, Victoire W T; de Graaf, Cees; Jager, Gerry

2013-05-01

Children's consumption of vegetables is still below recommendations. Since preference is the most important predictor of children's intake and most children dislike vegetables, new strategies are needed to increase their preferences for vegetables. Flavour nutrient learning (FNL) could be an effective mechanism to change preferences. Forty healthy toddlers were included in a randomized intervention study. During an intervention period of 7weeks, they consumed vegetable soups (endive and spinach) twice per week. Half of the group received a high-energy variant of one soup (e.g. HE spinach) and a low energy variant of the other (LE endive), whereas for the other half the order was reversed (HE endive, LE spinach). Primary outcome measures were preference and ad libitum consumption (with a maximum of 200g) of both vegetable products (LE), measured before, shortly after the intervention period, and 2 and 6months following conditioning to assess longer-term effects. After completion of the intervention period, 28 children (14 girls and 14 boys, age 35months; SD±8.3) met criteria for FNL to occur, and were included in further data analysis. Results showed a significant increase (~58g) in ad libitum intake for both vegetable soups (stable over time), but irrespective of the energy content. This indicates a robust effect of mere exposure on intake, but no FNL. For preference, however, results showed a significant shift in liking for the vegetable soup consistently paired with high energy, supporting FNL. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of a large wildfire on vegetation structure in a variable fire mosaic.

Science.gov (United States)

Foster, C N; Barton, P S; Robinson, N M; MacGregor, C I; Lindenmayer, D B

2017-12-01

Management guidelines for many fire-prone ecosystems highlight the importance of maintaining a variable mosaic of fire histories for biodiversity conservation. Managers are encouraged to aim for fire mosaics that are temporally and spatially dynamic, include all successional states of vegetation, and also include variation in the underlying "invisible mosaic" of past fire frequencies, severities, and fire return intervals. However, establishing and maintaining variable mosaics in contemporary landscapes is subject to many challenges, one of which is deciding how the fire mosaic should be managed following the occurrence of large, unplanned wildfires. A key consideration for this decision is the extent to which the effects of previous fire history on vegetation and habitats persist after major wildfires, but this topic has rarely been investigated empirically. In this study, we tested to what extent a large wildfire interacted with previous fire history to affect the structure of forest, woodland, and heath vegetation in Booderee National Park in southeastern Australia. In 2003, a summer wildfire burned 49.5% of the park, increasing the extent of recently burned vegetation (post-fire) to more than 72% of the park area. We tracked the recovery of vegetation structure for nine years following the wildfire and found that the strength and persistence of fire effects differed substantially between vegetation types. Vegetation structure was modified by wildfire in forest, woodland, and heath vegetation, but among-site variability in vegetation structure was reduced only by severe fire in woodland vegetation. There also were persistent legacy effects of the previous fire regime on some attributes of vegetation structure including forest ground and understorey cover, and woodland midstorey and overstorey cover. For example, woodland midstorey cover was greater on sites with higher fire frequency, irrespective of the severity of the 2003 wildfire. Our results show that even

Dynamic vegetation modeling of tropical biomes during Heinrich events

Science.gov (United States)

Handiani, Dian Noor; Paul, André; Dupont, Lydie M.

2010-05-01

Heinrich events are thought to be associated with a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), which in turn would lead to a cooling of the North Atlantic Ocean and a warming of the South Atlantic Ocean (the "bipolar seesaw" hypothesis). The accompanying abrupt climate changes occurred not only in the ocean but also on the continents. Changes were strongest in the Northern Hemisphere but were registered in the tropics as well. Pollen data from Angola and Brazil showed that climate changes during Heinrich events affected vegetation patterns very differently in eastern South America and western Africa. To understand the differential response in the terrestrial tropics, we studied the vegetation changes during Heinrich events by using a dynamic global vegetation model (TRIFFID) as part of the University of Victoria (UVic) Earth System-Climate Model (ESCM). The model results show a bipolar seesaw pattern in temperature and precipitation during a near-collapse of the AMOC. The succession in plant-functional types (PFTs) showed changes from forest to shrubs to desert, including spreading desert in northwest Africa, retreating broadleaf trees in West Africa and northern South America, but advancing broadleaf trees in Brazil. The pattern is explained by a southward shift of the tropical rainbelt resulting in a strong decrease in precipitation over northwest and West Africa as well as in northern South America, but an increase in precipitation in eastern Brazil. To facilitate the comparison between modeled vegetation results with pollen data, we diagnosed the distribution of biomes from the PFT coverage and the simulated model climate. The biome distribution was computed for Heinrich event 1 and the Last Glacial Maximum as well as for pre-industrial conditions. We used a classification of biomes in terms of "mega-biomes", which were defined following a scheme originally proposed by BIOME 6000 (v 4.2). The biome distribution of the Sahel region

Cascading ecohydrological transitions: Multiple changes in vegetation and hydrology over the past 500 years for a semiarid forest/woodland boundary zone in New Mexico, USA

Science.gov (United States)

Allen, Craig D.

2010-05-01

ponderosa pine in open stands maintained by frequent surface fires burning through herbaceous ground cover adequate to maintain ancient (>100,000 year old) soils, interspersed with young piñon-juniper savannas and woodlands on rockier fire-safe sites. Intensive livestock grazing from the late 1800's thru 1932 reduced the herbaceous ground cover, interrupting the surface fire regime, triggering massive establishment of fire-sensitive piñon and juniper throughout much of the 1900's. Severe drought in the 1950's killed all the ponderosa pine across an irregular ecotone shift zone up to 2 km wide, with no subsequent regeneration, leaving piñon-juniper woodland with accelerated, unsustainable erosion in desertified areas between tree clumps (averaging ~4 Mg/ha/year for the period 1995-2007 in a 1.09 ha study watershed). Warm drought in the early 2000's caused mass mortality of essentially all overstory piñon, leaving juniper as the only remaining tree dominant across huge areas. Ecohydrological processes are shifting again with declining runoff/erosion trends since 2003 as dead piñon skeletons fall and with increased abundances of shrubs and herbaceous surface cover, decreasing the connectivity of bare soil patches. The history of Frijolito Mesa illustrates multiple major transitions in vegetation since 1500 A.D., and substantial changes in runoff and erosion processes. This research has been used by the National Park Service since 2007 to implement an ecosystem restoration treatment (mechanical thinning of small trees with chainsaws and application of branch slash mulch) at a landscape scale of ~2000 ha. The treatments effectively conserve more water and soil onsite, increasing herbaceous ground cover and decreasing soil erosion rates 100-fold, stabilizing hundreds of archaeological sites and restoring the potential for natural surface fires. The ecohydrological history of this mesa also provides insight into how similar vegetation changes, such as episodes of widespread

Biogenic volatile organic compound emissions from vegetation fires.

Science.gov (United States)

Ciccioli, Paolo; Centritto, Mauro; Loreto, Francesco

2014-08-01

The aim of this paper was to provide an overview of the current state of the art on research into the emission of biogenic volatile organic compounds (BVOCs) from vegetation fires. Significant amounts of VOCs are emitted from vegetation fires, including several reactive compounds, the majority belonging to the isoprenoid family, which rapidly disappear in the plume to yield pollutants such as secondary organic aerosol and ozone. This makes determination of fire-induced BVOC emission difficult, particularly in areas where the ratio between VOCs and anthropogenic NOx is favourable to the production of ozone, such as Mediterranean areas and highly anthropic temperate (and fire-prone) regions of the Earth. Fire emissions affecting relatively pristine areas, such as the Amazon and the African savannah, are representative of emissions of undisturbed plant communities. We also examined expected BVOC emissions at different stages of fire development and combustion, from drying to flaming, and from heatwaves coming into contact with unburned vegetation at the edge of fires. We conclude that forest fires may dramatically change emission factors and the profile of emitted BVOCs, thereby influencing the chemistry and physics of the atmosphere, the physiology of plants and the evolution of plant communities within the ecosystem. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Development of Export Performance Scale for Fresh Vegetable-Fruit Sector

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Murat Keskinkılınç

2018-06-01

Full Text Available The purpose of this paper is to propose a scale for assessing the performance of foreign trade companies in fresh vegetable-fruit sector. As a first step, a qualitative interviews was conducted to the sample consists of the managers working in export companies. As a result of the interviews major problems of exporters were grouped. In the second phase of the study a questionnaire was formed and a survey was conducted to the larger sample. Subsequently, validity and reliability of the scales were determined by means of explanatory and confirmatory factor analyses and reliability analysis respectively. The theoretical contribution of this research is the development of a method for evaluation of export performance of foreign trade companies in fresh vegetable-fruit sector.

Nile Basin Vegetation Response and Vulnerability to Climate Change: A Multi-Sensor Remote Sensing Approach

Science.gov (United States)

Yitayew, M.; Didan, K.; Barreto-munoz, A.

2013-12-01

The Nile Basin is one of the world's water resources hotspot that is home to over 437 million people in ten riparian countries with 54% or 238 millions live directly within the basin. The basin like all other basins of the world is facing water resources challenges exacerbated by climate change and increased demand. Nowadays any water resource management action in the basin has to assess the impacts of climate change to be able to predict future water supply and also to help in the negotiation process. Presently, there is a lack of basin wide weather networks to understand sensitivity of the vegetation cover to the impacts of climate change. Vegetation plays major economic and ecological functions in the basin and provides key services ranging from pastoralism, agricultural production, firewood, habitat and food sources for the rich wildlife, as well as a major role in the carbon cycle and climate regulation of the region. Under the threat of climate change and the incessant anthropogenic pressure the distribution and services of the region's ecosystems are projected to change The goal of this work is to assess and characterize how the basin vegetation productivity, distribution, and phenology have changed over the last 30+ years and what are the key climatic drivers of this change. This work makes use of a newly generated multi-sensor long-term land surface data set about vegetation and phenology. Vegetation indices derived from remotely sensed surface reflectance data are commonly used to characterize phenology or vegetation dynamics accurately and with enough spatial and temporal resolution to support change detection. We used more than 30 years of vegetation index and growing season data from AVHRR and MODIS sensors compiled by the Vegetation Index and Phenology laboratory (VIP LAB) at the University of Arizona. Available climate data about precipitation and temperature for the corresponding 30 years period is also used for this analysis. We looked at the

Influence of shifting cultivation practices on soil-plant-beetle interactions.

Science.gov (United States)

Ibrahim, Kalibulla Syed; Momin, Marcy D; Lalrotluanga, R; Rosangliana, David; Ghatak, Souvik; Zothansanga, R; Kumar, Nachimuthu Senthil; Gurusubramanian, Guruswami

2016-08-01

Shifting cultivation (jhum) is a major land use practice in Mizoram. It was considered as an eco-friendly and efficient method when the cycle duration was long (15-30 years), but it poses the problem of land degradation and threat to ecology when shortened (4-5 years) due to increased intensification of farming systems. Studying beetle community structure is very helpful in understanding how shifting cultivation affects the biodiversity features compared to natural forest system. The present study examines the beetle species diversity and estimates the effects of shifting cultivation practices on the beetle assemblages in relation to change in tree species composition and soil nutrients. Scarabaeidae and Carabidae were observed to be the dominant families in the land use systems studied. Shifting cultivation practice significantly (P PERMANOVA), permutational multivariate analysis of dispersion (PERMDISP)) statistical analyses. Besides changing the tree species composition and affecting the soil fertility, shifting cultivation provides less suitable habitat conditions for the beetle species. Bioindicator analysis categorized the beetle species into forest specialists, anthropogenic specialists (shifting cultivation habitat specialist), and habitat generalists. Molecular analysis of bioindicator beetle species was done using mitochondrial cytochrome oxidase subunit I (COI) marker to validate the beetle species and describe genetic variation among them in relation to heterogeneity, transition/transversion bias, codon usage bias, evolutionary distance, and substitution pattern. The present study revealed the fact that shifting cultivation practice significantly affects the beetle species in terms of biodiversity pattern as well as evolutionary features. Spatiotemporal assessment of soil-plant-beetle interactions in shifting cultivation system and their influence in land degradation and ecology will be helpful in making biodiversity conservation decisions in the

Analysis of the Market Structure and Shift-effects in North China Ports

Directory of Open Access Journals (Sweden)

Manlu Liu, Doctoral Student

2016-09-01

Full Text Available This study divides the foreign trade traffic of major North China ports into export and import cargoes for the past 10 years. Then, the concentration ratios and shift effects are analyzed in order to determine their relationships with the ports’ competition structures. Here, the HHI, a BCG matrix analysis, and the shift effects are applied as study methods. The results indicate that the oligopoly market structure of major North China ports has gradually decreased. Furthermore, the concentration ratios of import cargoes are higher than those of export cargoes, indicating that competition to attract import cargoes will intensify. Therefore, the effects of the South Korea–China FTA mean that the competition structures of these ports with regard to export and import cargoes are highly likely to be differentiated further over time.

Review of Vegetable Market Development in China

Institute of Scientific and Technical Information of China (English)

Chaoping; LUO; Yuandong; NI; Qiong; ZHAI

2013-01-01

This paper has reviewed vegetable market development from vegetable circulation system, the develop history of the liberalize vegetable market and the growth of the vegetable wholesale market in China. From the development of vegetables market in China and its characteristics: the development of vegetable market in China is related to vegetable market system, the change of institution, some technology development and infrastructure. this paper has put forward some related measures to perfect the vegetable market and improve the vegetable circulation efficiency in China.

Temporal Changes in Coupled Vegetation Phenology and Productivity are Biome-Specific in the Northern Hemisphere

Directory of Open Access Journals (Sweden)

Lanhui Wang

2017-12-01

Full Text Available Global warming has greatly stimulated vegetation growth through both extending the growing season and promoting photosynthesis in the Northern Hemisphere (NH. Analyzing the combined dynamics of such trends can potentially improve our current understanding on changes in vegetation functioning and the complex relationship between anthropogenic and climatic drivers. This study aims to analyze the relationships (long-term trends and correlations of length of vegetation growing season (LOS and vegetation productivity assessed by the growing season NDVI integral (GSI in the NH (>30°N to study any dependency of major biomes that are characterized by different imprint from anthropogenic influence. Spatial patterns of converging/diverging trends in LOS and GSI and temporal changes in the coupling between LOS and GSI are analyzed for major biomes at hemispheric and continental scales from the third generation Global Inventory Monitoring and Modeling Studies (GIMMS Normalized Difference Vegetation Index (NDVI dataset for a 32-year period (1982–2013. A quarter area of the NH is covered by converging trends (consistent significant trends in LOS and GSI, whereas diverging trends (opposing significant trends in LOS and GSI cover about 6% of the region. Diverging trends are observed mainly in high latitudes and arid/semi-arid areas of non-forest biomes (shrublands, savannas, and grasslands, whereas forest biomes and croplands are primarily characterized by converging trends. The study shows spatially-distinct and biome-specific patterns between the continental land masses of Eurasia (EA and North America (NA. Finally, areas of high positive correlation between LOS and GSI showed to increase during the period of analysis, with areas of significant positive trends in correlation being more widespread in NA as compared to EA. The temporal changes in the coupled vegetation phenology and productivity suggest complex relationships and interactions that are induced

A Review on the Effect of Drying on Antioxidant Potential of Fruits and Vegetables.

Science.gov (United States)

Kamiloglu, Senem; Toydemir, Gamze; Boyacioglu, Dilek; Beekwilder, Jules; Hall, Robert D; Capanoglu, Esra

2016-07-29

The role of antioxidants in human nutrition has gained increased interest, especially due to their associated health beneficial effects for a number of chronic diseases, including cardiovascular diseases and certain types of cancer. Fruits and vegetables are perishable and difficult to preserve as fresh products. Dried fruits and vegetables can be easily stored, transported at relatively low cost, have reduced packing costs, and their low water content delays microbial spoilage. Air-, freeze-, microwave- and sun-drying are among the most thoroughly studied drying methods. This review provides an overview of recent findings on the effects of different drying techniques on major antioxidants of fruits and vegetables. In particular, changes in ascorbic acid, carotenoids, flavonoids, phenolic acids, total phenolics, and antioxidant activity are discussed in detail.

Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3--4 days.

Science.gov (United States)

Reinberg, A; Migraine, C; Apfelbaum, M; Brigant, L; Ghata, J; Vieux, N; Laporte, A; Nicolai

1979-03-01

Seven healthy adult men, five shift-workers and two non-shift-workers (from 21 to 36 years; mean = 26.4) volunteered to record what and when they ate, both at work and at home, every day, during eight consecutive weeks (Oct. - Dec. 1974). 1) All the subjects maintained the timing of main-meal (lunch and supper) during all shifts. 2) The major intake of protein and lipid was concentrated on the two main meals during all shifts. 3) Only the pattern of carbohydrate intake was modified by the shift-work: e.g. night-shift is associated with nibbling behaviour. 4) However, shift-work and in particular the occurence of nibbling behaviour did not result in change either in the mean 24 h caloric intake, or in the percentage of protein calories. 5) The comparison between the constancy of the timing of major meals and the shift of the timing of circadian rhythm acrophases of the 5 shift-workers leads to conclude that meal timing had a poor synchronizing effect, if any.

Availability of commonly consumed and culturally specific fruits and vegetables in African-american and Latino neighborhoods.

Science.gov (United States)

Grigsby-Toussaint, Diana S; Zenk, Shannon N; Odoms-Young, Angela; Ruggiero, Laurie; Moise, Imelda

2010-05-01

Although the importance of culture in shaping individual dietary behaviors is well-documented, cultural food preferences have received limited attention in research on the neighborhood food environment. The purpose of this study was to assess the availability of commonly consumed and culturally specific fruits and vegetables in retail food stores located in majority African-American and Latino neighborhoods in southwest Chicago, IL. A cross-sectional survey of 115 stores (15% grocery stores, 85% convenience/corner stores) in African-American neighborhoods and 110 stores (45% grocery stores, 55% convenience/corner stores) in Latino neighborhoods was conducted between May and August of 2006. chi(2) tests were used to assess differences in the availability (presence/absence) of commonly consumed (n=25) and culturally specific fruits and vegetables for African Americans (n=16 varieties) and Latinos (n=18 varieties). Stores located in neighborhoods in which the majority of residents were African American or Latino were more likely to carry fresh fruits and vegetables that were culturally relevant to the dominant group. For example, grocery stores located in Latino neighborhoods were more likely to carry chayote (82.0% vs 17.6%, P<0.05), whereas grocery stores located in African-American neighborhoods were more likely to carry black-eyed peas (52.9% vs 20%, P<0.05). Most stores, however, carried fewer than 50% of commonly consumed or culturally specific fruits and vegetables. Findings from this study highlight that limited availability of culturally specific as well as commonly consumed fruits and vegetables in the neighborhood may be a barrier to fruit and vegetable consumption among African Americans and Latinos. Copyright 2010 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

Influence of Vegetation on Long-term Phosphorus Sequestration in Subtropical Treatment Wetlands.

Science.gov (United States)

Bhomia, R K; Reddy, K R

2018-03-01

Sustainable operation of a treatment wetland depends on its continued treatment of influent water to achieve desired outflow water quality targets. Water treatment or nutrient reduction is attained by a combination of biotic and abiotic processes. We studied one of the world's largest treatment wetlands established to revive the Florida Everglades from impacts of excessive phosphorus (P) inputs. Phosphorus retained in the treatment wetlands is sequestered within the accumulated material via biotic and abiotic pathways that are influenced by the existing wetland vegetation. Recently accreted soils (RAS) provide a major sink for stored P, and long-term P removal efficiency of treatment wetlands is governed by the stability of accreted P because more stable P pools are less susceptible to mobilization and loss. We quantified reactive P (extracted with acid and alkali) and nonreactive P (not extracted with acid and alkali) pools in wetland soils by using an operationally defined P fractionation scheme and assessed the effect of emergent vs. submerged vegetation communities on stability of sequestered P. Reactive P comprised 63 to 79% of total P in wetland soils without a clear difference between two vegetation groups. The quantities of reactive P forms (inorganic vs. organic P) were significantly different between two vegetation types. A higher proportion of reactive P was stored as organic P in flocculent detrital organic matter (floc) and RAS under emergent vegetation (46-47% total P) in comparison with submerged vegetation (21-34% total P). The dominant P removal pathway in the submerged vegetation system was associated with calcium whereas plant uptake and peat burial appeared to be the main pathway in the emergent vegetation system. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.