Spatial decoupling of facilitation and competition at the origin of gapped vegetation patterns.

Science.gov (United States)

Barbier, Nicolas; Couteron, Pierre; Lefever, René; Deblauwe, Vincent; Lejeune, Olivier

2008-06-01

Spatially periodic vegetation patterns, forming gaps, bands, labyrinths, or spots, are characteristic of arid and semiarid landscapes. Self-organization models can explain this variety of structures within a unified conceptual framework. All these models are based on the interplay of positive and negative effects of plants on soil water, but they can be divided according to whether they assume the interactions to be mediated by water redistribution through runoff/diffusion or by plants' organs. We carried out a multi-proxy approach of the processes operating in a gapped pattern in southwest Niger dominated by a shrub species. Soil moisture within the root layer was monitored in time and space over one month of the rainy season. Soil water recharge displayed no spatial variation with respect to vegetation cover, but the stock half-life under cover was twice that of bare areas. A kernel of facilitation by the aboveground parts of shrubs was parameterized, and soil water half-life was significantly correlated to the cumulated facilitative effects of shrubs. The kernel range was found to be smaller than the canopy radius (81%). This effect of plants on soil water dynamics, probably through a reduction of evaporation by shading, is shown to be a better explanatory variable than potentially relevant soil and topography parameters. The root systems of five individuals of Combretum micranthum G. Don were excavated. Root density data were used as a proxy to parameterize a kernel function of interplant competition. The range of this kernel was larger than the canopy radius (125%). The facilitation-to-competition range ratio, reflecting the above-to-belowground ratio of plant lateral extent, was smaller than 1 (0.64), a result supporting models assuming that patterning may emerge from an adaptation of plant morphology to aridity and shallow soils by means of an extended lateral root system. Moreover, observed soil water gradients had directions opposite to those assumed by

Innovative solutions in traceability to improve the competitiveness of a local fruit and vegetable retailing system

Directory of Open Access Journals (Sweden)

Miklós Pakurár

2015-05-01

Full Text Available The aim of the research is to investigate the network of local fruit and vegetable products from “farm to fork”, to uncover the hidden processes in traceability and to advise innovations in the retailing system to improve the competitiveness of the sector. Traceability is an ability to track any food that will be consumed throughout the processes of production, processing and distribution. The research investigates what the customer knows about the origin and treatments of purchased products and what further information would satisfy the consumer. The study explores the flow of information amongst the chain members: producers, wholesalers, small-scale retailers, and customers. Based on interviews and questionnaires, regression analysis and ordinal regression procedure were performed. Innovative solutions to make the retailing competitive should be aligned with the precise knowledge of the consumer. The results of the research show that deficiencies in data collection, data erosion, low level of cooperation of supply chain partners, not paying more attention for more detailed information, and inadequate control are the main problems of the traceability in fruit and vegetable chains.

SELECTED ISSUES OF COMPETITIVENESS POTENTIAL OF FRUIT AND VEGETABLE PROCESSING COMPANIES LOCATED IN THE WIELKOPOLSKIE VOIVODESHIP

Directory of Open Access Journals (Sweden)

Joanna Smoluk-Sikorska

2014-09-01

Full Text Available The paper discusses results of the research concerning potential and strategy of competitiveness of companies of fruit and vegetable processing industry located in the Wielkopolskie voivodeship. Special attention was paid to the assessment of the companies’ financial situation, their production resources, management system and adopted development strategies. The investigated companies are characterised by strong domestic market position, which is mainly results of the assessment of their financial situation. They asses competitiveness potential very high, particularly human resources and related with them management skills. Furthermore, most of the companies assess the use of strategy of quality control and specialisation strategy as high or very high.

Network succession reveals the importance of competition in response to emulsified vegetable oil amendment for uranium bioremediation.

Science.gov (United States)

Deng, Ye; Zhang, Ping; Qin, Yujia; Tu, Qichao; Yang, Yunfeng; He, Zhili; Schadt, Christopher Warren; Zhou, Jizhong

2016-01-01

Discerning network interactions among different species/populations in microbial communities has evoked substantial interests in recent years, but little information is available about temporal dynamics of microbial network interactions in response to environmental perturbations. Here, we modified the random matrix theory-based network approach to discern network succession in groundwater microbial communities in response to emulsified vegetable oil (EVO) amendment for uranium bioremediation. Groundwater microbial communities from one control and seven monitor wells were analysed with a functional gene array (GeoChip 3.0), and functional molecular ecological networks (fMENs) at different time points were reconstructed. Our results showed that the network interactions were dramatically altered by EVO amendment. Dynamic and resilient succession was evident: fairly simple at the initial stage (Day 0), increasingly complex at the middle period (Days 4, 17, 31), most complex at Day 80, and then decreasingly complex at a later stage (140-269 days). Unlike previous studies in other habitats, negative interactions predominated in a time-series fMEN, suggesting strong competition among different microbial species in the groundwater systems after EVO injection. Particularly, several keystone sulfate-reducing bacteria showed strong negative interactions with their network neighbours. These results provide mechanistic understanding of the decreased phylogenetic diversity during environmental perturbations. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

[Effect of habitat and interspecific competition on Apis cerana cerana colony distribution].

Science.gov (United States)

Yu, Linsheng; Han, Shengming

2003-04-01

Habitat change and interspecific competition were the main factors affecting, Apis cerana cerana colony distribution among Wannan and Wanxi Dabie mountainous areas, Jianghuai area and Huaibei plain. Wannan and Wanxi Dabie mountainous areas were the ideal places for Apis cerana cerana' habitation and propogation, in which, there were integrated natural vegetation, fine ecological condition, abundant nectariferous plants, and Apis cerana cerana had large colony size, wide distribution, high density, no disturbances of natural mating, and was dominant interspecific competition. In Jianghuai area and Huaibei plain, there were small covering of natural vegetation, different degree of degradation of ecological balance, few kinds of nectariferous plants with almost the same blooming periods, natural mating perturbed by Apis mellifera ligustica for Apis cerana cerana, and which was inferior in interspecific competition, colony size sharply decreased, distribution area reduced, and density cut down to a great extent. In Huaibei plain, the negative factors were more conspicuous.

Water management can reinforce plant competition in salt-affected semi-arid wetlands

Science.gov (United States)

Coletti, Janaine Z.; Vogwill, Ryan; Hipsey, Matthew R.

2017-09-01

The diversity of vegetation in semi-arid, ephemeral wetlands is determined by niche availability and species competition, both of which are influenced by changes in water availability and salinity. Here, we hypothesise that ignoring physiological differences and competition between species when managing wetland hydrologic regimes can lead to a decrease in vegetation diversity, even when the overall wetland carrying capacity is improved. Using an ecohydrological model capable of resolving water-vegetation-salt feedbacks, we investigate why water surface and groundwater management interventions to combat vegetation decline have been more beneficial to Casuarina obesa than to Melaleuca strobophylla, the co-dominant tree species in Lake Toolibin, a salt-affected wetland in Western Australia. The simulations reveal that in trying to reduce the negative effect of salinity, the management interventions have created an environment favouring C. obesa by intensifying the climate-induced trend that the wetland has been experiencing of lower water availability and higher root-zone salinity. By testing alternative scenarios, we show that interventions that improve M. strobophylla biomass are possible by promoting hydrologic conditions that are less specific to the niche requirements of C. obesa. Modelling uncertainties were explored via a Markov Chain Monte Carlo (MCMC) algorithm. Overall, the study demonstrates the importance of including species differentiation and competition in ecohydrological models that form the basis for wetland management.

The Potential Research of Catch Crop in Decrease Soil Nitrate Under Greenhouse Vegetable Production

Directory of Open Access Journals (Sweden)

YIN Xing

2015-06-01

Full Text Available In order to clarify the impact of catch crops on greenhouse vegetable soil nitrate, explore the mechanism of barrier and controll soil nitrogen leaching losses in greenhouse, and provide a theoretical basis for control nitrogen leaching and prevention of groundwater pollution, this study selected the traditional greenhouse vegetable rotation system in North China plain as research subjects, using field situ remediation technologies on deep-root planting catch crops in the vegetable fallow period by sweet corn, Achyranthes bidentata and white Chrysanthemum. The results showed that: nitrogen content and nitrogen uptake of sweet corn and sweet corn with Achyranthes bidentata intercropping were the highest, respectively 20.11 t·hm-2, 19.62 t·hm-2 and 240.34 kg·hm-2, 287.56 kg·hm-2, significantly higher than white Chrysanthemum. The density of root length and root dry weight decreased with soil depth in the profiles, root length density was demonstrated in order as: intercropping sweet corn> sweet corn> white Chrysanthemum> intercropping Achyranthes bidentata blume. The reduction of NO3--N of sweet corn reached 907.87 kg·hm-2 in soil profile 0~200 cm, significantly higher than sweet corn and hyssop intercropping and white Chrysanthemums. In the interim period of vegetable crop rotation, planting catch crops could effectively reduce nitrate accumulation in the soil, control the soil profile nitrate leaching down.

Competitive balance in national European soccer competitions

NARCIS (Netherlands)

Haan, M.A.; Koning, R.H.; van Witteloostuijn, A.; Albert, Jim; Koning, Ruud H.

2007-01-01

According to popular belief, competitive balance in national soccer competitions in Europe has decreased due to the Bosman ruling and the introduction of the Champions League. We test this hypothesis using data from 7 national competitions, for a host of indicators. We find some evidence for

Radioisotope method for characterization of vegetable tannins, extracted from waste of forestry production in Cuba

International Nuclear Information System (INIS)

Santana Romero, J.L.; Martinez Luzardo, F.; Codorniu Hernandez, E.; Vargas Guerra, L.; Melo Cala, P.; Garcia Guillen, M.; Isaac Olive, K.; Estevez, P.; Roque Cordoba, A.; Benitez, M.

2002-01-01

Vegetable tannins are polyphenolic plants secondary metabolites, widely distributed in all parts of trees and herbs. The role of these substances in many metabolic processes is very important. Vegetable tannins have been implicated as probable antinutritional factors, decreasing the assimilation of diet protein assimilation by cattle. On the other hand, protective antioxidant and antimutagenic properties have been ascribed for these compounds. Characterization of vegetable tannins is important in order to find new sources of natural raw materials with medical and pharmaceutical applications. Protein precipitation capacity as a function of pH, competitive protein and ADN binding assays and the determination of tannins concentration are described. Radioisotope labeled protein and tannins were used in all of the determinations. (author)

Recent developments in microbial oils production: a possible alternative to vegetable oils for biodiesel without competition with human food?

Directory of Open Access Journals (Sweden)

Gwendoline Christophe

2012-02-01

Full Text Available Since centuries vegetable oils are consumed as human food but it also finds applications in biodiesel production which is attracting more attention. But due to being in competition with food it could not be sustainable and leads the need to search for alternative. Nowdays microbes-derived oils (single cell oils seem to be alternatives for biodiesel production due to their similar composition to that of vegetable oils. However, the cold flow properties of the biodiesel produced from microbial oils are unacceptable and have to be modified by an efficient transesterification. Glycerol which is by product of transesterification can be valorised into some more useful products so that it can also be utilised along with biodiesel to simplify the downstream processing. The review paper discusses about various potent microorganisms for biodiesel production, enzymes involved in the lipid accumulation, lipid quantification methods, catalysts used in transesterification (including enzymatic catalyst and valorisation of glycerol.

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.

Planted Black Walnut Does Well on Cleared Forest Sites -- if Competition is Controlled

Science.gov (United States)

John E. Krajicek

1975-01-01

After seven growing seasons, survival of black walnut seedlings planted in cleared forest openings did not differ by competition control treatments. The trees grew somewhat larger where all competing vegetation was controlled but almost as large where only herbaceous competition was controlled. Controlling only woody vegetation was no better than no control of any...

Combined effects of plant competition and insect herbivory hinder invasiveness of an introduced thistle.

Science.gov (United States)

Suwa, Tomomi; Louda, Svata M

2012-06-01

The biotic resistance hypothesis is a dominant paradigm for why some introduced species fail to become invasive in novel environments. However, predictions of this hypothesis require further empirical field tests. Here, we focus on evaluating two biotic factors known to severely limit plants, interspecific competition and insect herbivory, as mechanisms of biotic resistance. We experimentally evaluated the independent and combined effects of three levels of competition by tallgrass prairie vegetation and two levels of herbivory by native insects on seedling regeneration, size, and subsequent flowering of the Eurasian Cirsium vulgare, a known invasive species elsewhere, and compared its responses to those of the ecologically similar and co-occurring native congener C. altissimum. Seedling emergence of C. vulgare was greater than that of C. altissimum, and that emergence was reduced by the highest level of interspecific competition. Insect leaf herbivory was also greater on C. vulgare than on C. altissimum at all levels of competition. Herbivory on seedlings dramatically decreased the proportion of C. vulgare producing flower heads at all competition levels, but especially at the high competition level. Competition and herbivory interacted to significantly decrease plant survival and biomass, especially for C. vulgare. Thus, both competition and herbivory limited regeneration of both thistles, but their effects on seedling emergence, survival, size and subsequent reproduction were greater for C. vulgare than for C. altissimum. These results help explain the unexpectedly low abundance recorded for C. vulgare in western tallgrass prairie, and also provide strong support for the biotic resistance hypothesis.

Apparent competition and native consumers exacerbate the strong competitive effect of an exotic plant species.

Science.gov (United States)

Orrock, John L; Dutra, Humberto P; Marquis, Robert J; Barber, Nicholas

2015-04-01

Direct and indirect effects can play a key role in invasions, but experiments evaluating both are rare. We examined the roles of direct competition and apparent competition by exotic Amur honeysuckle (Lonicera maackii) by manipulating (1) L. maackii vegetation, (2) presence of L. maackii fruits, and (3) access to plants by small mammals and deer. Direct competition with L. maackii reduced the abundance and richness of native and exotic species, and native consumers significantly reduced the abundance and richness of native species. Although effects of direct competition and consumption were more pervasive, richness of native plants was also reduced through apparent competition, as small-mammal consumers reduced richness only when L. maackii fruits were present. Our experiment reveals the multiple, interactive pathways that affect the success and impact of an invasive exotic plant: exotic plants may directly benefit from reduced attack by native consumers, may directly exert strong competitive effects on native plants, and may also benefit from apparent competition.

Effects of fertility, weed density and crop competition on biomass partitioning in Centaurea cyanus L.

Directory of Open Access Journals (Sweden)

Łukasz Chachulski

2014-01-01

Full Text Available The influence of environmental factors on biomass partitioning of annual arable weed Centaurea cyanus was analysed. We investigated the effect of fertilisation, density and competition with the winter rye crop on the reproductive investment. Three fertiliser treatments and three density levels were applied. In Centaurea cyanus differences in the pattern of biomass allocation to reproduction are related to plant size. The relationship between reproductive and vegetative mass is close to linear. It is consistent with the model of linear size-dependent reproductive output. In Centaurea cyanus this model worked well for size differences that have been generated by interspecific competition, nutrients supply and density. Our data support the hypothesis that plastic changes in relationship between vegetative and generative biomass are environmentally-induced. Significantly different relationship between vegetative and reproductive biomass were detected among populations growing at different density and fertility levels. The fertilisation with mineral fertiliser and manure resulted in an increase of generative biomass allocated to flowerheads and a decrease of reproductive effort. Generative dry weight increased more rapidly with plant size in higher densities of population and at lower fertility levels. The experiment showed that the rate of weight allocated to reproductive structures was bigger under the pressure of competition with cereal crop. At low fertility level and high density, when the individuals were small, generative biomass increased faster with plant size. The production of seeds was not directly dependent on biomass allocated into total reproductive structures. At low level, of nutrient supply C. cyanus gave more offspring per gram of its biomass. We discuss the results in context of life-history theory. From the strategic point of view, size-dependent variation in reproductive effort and in efficiency of reproduction can be

Detecting vegetation-precipitation feedbacks in mid-Holocene North Africa from two climate models

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi; Notaro, Michael; Liu, Zhengyu; Gallimore, Robert; Levis, Samuel; Kutzbach, John E.

2008-03-31

Using two climate-vegetation model simulations from the Fast Ocean Atmosphere Model (FOAM) and the Community Climate System Model (CCSM, version 2), we investigate vegetation-precipitation feedbacks across North Africa during the mid-Holocene. From mid-Holocene snapshot runs of FOAM and CCSM2, we detect a negative feedback at the annual timescale with our statistical analysis. Using the Monte- Carlo bootstrap method, the annual negative feedback is further confirmed to be significant in both simulations. Additional analysis shows that this negative interaction is partially caused by the competition between evaporation and transpiration in North African grasslands. Furthermore, we find the feedbacks decrease with increasing timescales, and change signs from positive to negative at increasing timescales in FOAM. The proposed mechanism for this sign switch is associated with the different persistent timescales of upper and lower soil water contents, and their interactions with vegetation and atmospheric precipitation.

Molecular mechanisms of plant competition: neighbour detection and response strategies

NARCIS (Netherlands)

Pierik, R.; Mommer, L.; Voesenek, L.A.C.J.

2013-01-01

Plant competition determines the diversity and species abundance of natural communities as well as potential yields in agricultural systems. Understanding the mechanisms of plant competition is instrumental to understanding plant performance in true vegetations. In this review, we will address

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).

Dietary intake of fiber, fruit and vegetables decreases the risk of incident kidney stones in women: A women's health initiative report

OpenAIRE

Sorensen, MD; Hsi, RS; Chi, T; Shara, N; Wactawski-Wende, J; Kahn, AJ; Wang, H; Hou, L; Stoller, ML

2014-01-01

© 2014 American Urological Association Education and Research, Inc. Results Mean age of the women was 64±7 years, 85% were white and 2,937 (3.5%) experienced a kidney stone in a median followup of 8 years. In women with no history of kidney stones higher total dietary fiber (6% to 26% decreased risk, p < 0.001), greater fruit intake (12% to 25% decreased risk, p < 0.001) and greater vegetable intake (9% to 22% decreased risk, p=0.002) were associated with a decreased risk of incident kidney...

Species interactions and response time to climate change: ice-cover and terrestrial run-off shaping Arctic char and brown trout competitive asymmetries

Science.gov (United States)

Finstad, A. G.; Palm Helland, I.; Jonsson, B.; Forseth, T.; Foldvik, A.; Hessen, D. O.; Hendrichsen, D. K.; Berg, O. K.; Ulvan, E.; Ugedal, O.

2011-12-01

There has been a growing recognition that single species responses to climate change often mainly are driven by interaction with other organisms and single species studies therefore not are sufficient to recognize and project ecological climate change impacts. Here, we study how performance, relative abundance and the distribution of two common Arctic and sub-Arctic freshwater fishes (brown trout and Arctic char) are driven by competitive interactions. The interactions are modified both by direct climatic effects on temperature and ice-cover, and indirectly through climate forcing of terrestrial vegetation pattern and associated carbon and nutrient run-off. We first use laboratory studies to show that Arctic char, which is the world's most northernmost distributed freshwater fish, outperform trout under low light levels and also have comparable higher growth efficiency. Corresponding to this, a combination of time series and time-for-space analyses show that ice-cover duration and carbon and nutrient load mediated by catchment vegetation properties strongly affected the outcome of the competition and likely drive the species distribution pattern through competitive exclusion. In brief, while shorter ice-cover period and decreased carbon load favored brown trout, increased ice-cover period and increased carbon load favored Arctic char. Length of ice-covered period and export of allochthonous material from catchments are major, but contrasting, climatic drivers of competitive interaction between these two freshwater lake top-predators. While projected climate change lead to decreased ice-cover, corresponding increase in forest and shrub cover amplify carbon and nutrient run-off. Although a likely outcome of future Arctic and sub-arctic climate scenarios are retractions of the Arctic char distribution area caused by competitive exclusion, the main drivers will act on different time scales. While ice-cover will change instantaneously with increasing temperature

Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

DEFF Research Database (Denmark)

Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

2015-01-01

Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...

Hidden vegetables: an effective strategy to reduce energy intake and increase vegetable intake in adults.

Science.gov (United States)

Blatt, Alexandria D; Roe, Liane S; Rolls, Barbara J

2011-04-01

The overconsumption of energy-dense foods leads to excessive energy intakes. The substitution of low-energy-dense vegetables for foods higher in energy density can help decrease energy intakes but may be difficult to implement if individuals dislike the taste of vegetables. We investigated whether incorporating puréed vegetables to decrease the energy density of entrées at multiple meals reduced daily energy intakes and increased daily vegetable intakes. In this crossover study, 20 men and 21 women ate ad libitum breakfast, lunch, and dinner in the laboratory once a week for 3 wk. Across conditions, entrées at meals varied in energy density from standard versions (100% condition) to reduced versions (85% and 75% conditions) by the covert incorporation of 3 or 4.5 times the amount of puréed vegetables. Entrées were accompanied by unmanipulated side dishes. Participants rated their hunger and fullness before and after meals. Subjects consumed a consistent weight of foods across conditions of energy density; thus, the daily energy intake significantly decreased by 202 ± 60 kcal in the 85% condition (P kcal in the 75% condition (P Daily vegetable consumption significantly increased from 270 ± 17 g of vegetables in the 100% condition to 487 ± 25 g of vegetables in the 75% condition (P < 0.0001). Despite the decreased energy intake, ratings of hunger and fullness did not significantly differ across conditions. Entrées were rated as similar in palatability across conditions. Large amounts of puréed vegetables can be incorporated into various foods to decrease the energy density. This strategy can lead to substantial reductions in energy intakes and increases in vegetable intakes. This trial was registered at clinicaltrials.gov as NCT01165086.

How light competition between plants affects their response to climate change.

Science.gov (United States)

van Loon, Marloes P; Schieving, Feike; Rietkerk, Max; Dekker, Stefan C; Sterck, Frank; Anten, Niels P R

2014-09-01

How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2 concentration, and modeled the extent to which local plant-plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO2 and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO2 increase. When CO2 elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO2 on leaf area index (LAI) well within the range of observed effects obtained by Free air CO2 enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

The responses of crop - wild Brassica hybrids to simulated herbivory and interspecific competition: implications for transgene introgression.

Science.gov (United States)

Sutherland, Jamie P; Justinova, Lenka; Poppy, Guy M

2006-01-01

Brassica rapa grows as a wild and weedy species throughout the world and is the most likely recipient of transgenes from GM oilseed rape. For transgene introgression to occur, the critical step which must be realized, is the formation of an F1 hybrid. Concerns exist that hybrid populations could be more vigorous and competitive compared to the parental species. This study examines the effect of simulated herbivory and interspecific competition on the vegetative and reproductive performance of non-transgenic F1 hybrids and their parental lines. Several vegetative and reproductive performance measures were used to determine the effect of simulated herbivory and competition on the Brassica lines, including leaf length and biomass for herbivory and seedling height and biomass for competition. For defoliation experiments, B. rapa showed little response in terms of leaf length but B. napus and the F1 hybrid responded negatively. Brassica rapa showed elevated biomass responses, but B. napus and the hybrid demonstrated negative responses to defoliation. Defoliation at the cotyledon stage had a slight effect upon final biomass with the F1 hybrid performing significantly worse than B. napus, although seed counts were not significantly different. For the series of competition experiments, hybrids seemed to be more similar to B. rapa in terms of early seedling growth and reproductive measures. The underperformance of hybrid plants when challenged by herbivory and competition, could potentially decrease survivorship and explain the rarity of hybrids in field surveys. However, should transgene introgression occur, the dynamics of hybrids could change radically thus increasing the risk of gene flow from a transgenic oilseed rape crop to the wild recipient.

Use of nuclear techniques for characterization of vegetable tannins, extracted from waste of forestry production in Cuba

International Nuclear Information System (INIS)

Santana Romero, J. L.; Martinez Luzardo, F.; Vargas Guerra, L.; Melo Cala, P.; Garcia Guillen, M.; Isaac Olive, K.; Codorniu Hernandez, E.; Estevez, P.; Roque, Cordoba A.; Benitez, M.

1999-01-01

Vegetable Tannins are polyphenolic plant secondary metabolites, widely distributed in all parts of trees and herbs.The role of these substances in many metabolic processes is very important. Vegetable tannins have probably implication as anti nutritional factors, decreasing up-take of diet protein assimilation by cattle. On the other hand, protective antioxidant and antimutagenic properties has been describes for these compounds. Characterization of vegetable tannins is an important task in order to find new sources of natural raw materials with several applications. Analytical determination of tannins and their characterization is still a problem at present days in order to qualify the food quality for ruminants. Protein precipitation capacity as function of pH, competitive protein and ADN binding assays , and determination of tannins concentration are describes.Radioisotopic labelling of protein and tannins were used in order to carried out all the determinations

An Invasive Clonal Plant Benefits from Clonal Integration More than a Co-Occurring Native Plant in Nutrient-Patchy and Competitive Environments

Science.gov (United States)

You, Wenhua; Fan, Shufeng; Yu, Dan; Xie, Dong; Liu, Chunhua

2014-01-01

Many notorious invasive plants are clonal, however, little is known about the different roles of clonal integration effects between invasive and native plants. Here, we hypothesize that clonal integration affect growth, photosynthetic performance, biomass allocation and thus competitive ability of invasive and native clonal plants, and invasive clonal plants benefit from clonal integration more than co-occurring native plants in heterogeneous habitats. To test these hypotheses, two stoloniferous clonal plants, Alternanthera philoxeroides (invasive), Jussiaea repens (native) were studied in China. The apical parts of both species were grown either with or without neighboring vegetation and the basal parts without competitors were in nutrient- rich or -poor habitats, with stolon connections were either severed or kept intact. Competition significantly reduced growth and photosynthetic performance of the apical ramets in both species, but not the biomass of neighboring vegetation. Without competition, clonal integration greatly improved the growth and photosynthetic performance of both species, especially when the basal parts were in nutrient-rich habitats. When grown with neighboring vegetation, growth of J. repens and photosynthetic performance of both species were significantly enhanced by clonal integration with the basal parts in both nutrient-rich and -poor habitats, while growth and relative neighbor effect (RNE) of A. philoxeroides were greatly improved by clonal integration only when the basal parts were in nutrient-rich habitats. Moreover, clonal integration increased A. philoxeroides's biomass allocation to roots without competition, but decreased it with competition, especially when the basal ramets were in nutrient-rich sections. Effects of clonal integration on biomass allocation of J. repens was similar to that of A. philoxeroides but with less significance. These results supported our hypothesis that invasive clonal plants A. philoxeroides benefits

Decreasing of transfer of caesium and strontium radionuclides from soil to vegetation - Use of modified aluminosilicates for decreasing of transfer of caesium and strontium radionuclides from soil to vegetation

Energy Technology Data Exchange (ETDEWEB)

Voronina, Anna V.; Blinova, Marina O.; Semenischev, Vladimir S.; Kutergin, Andrey S. [Ural federal university, 620002 Ekaterinburg (Russian Federation)

2014-07-01

The method of addition of sorbents to soils is seemed to be the most efficient for decreasing of transfer of radionuclides from soil to vegetation. Using sorbents should possess affinity to natural systems, high specificity and selectivity and also irreversibility of sorption of radionuclides for effective retention of radionuclides as well as to prevent their migration into vegetation and further movement through food chains. Specificity, selectivity and reversibility of sorption of caesium and strontium radionuclides by natural aluminosilicates (glauconite, clinoptilolite) and modified ferrocyanide sorbents based on them was studied in this work. It was shown that the natural glauconite sorbs caesium from tap water with distribution coefficient K{sub d} = 10{sup (3.5±0.1)} mL/g, static exchange capacity of Cs is 11.0 mg/g; it shows lower specificity to strontium: K{sub d} = 10(2.5±0.1) mL/g, static exchange capacity = 9 mg/g. For clinoptilolite these parameters are for caesium K{sub d} = 10(4.4±0.5) mL/g, static exchange capacity 210 mg/g; for strontium K{sub d} = 10(3.5±0.1) mL/g, capacity = 12 mg/g. Ferrocyanide sorbents concentrate caesium radionuclides more effectively: distribution coefficient of Cs from tap water by mixed nickel-potassium ferrocyanide based on glauconite is 10(5.9±1.6) mL/g, static exchange capacity of Cs is (63.0±2.0) mg/g; for mixed nickel-potassium ferrocyanide based on clinoptilolite these characteristics are respectively 10(7.4±1.3) mL/g, 500 mg/g. In case of modified sorbents specificity to strontium remains the same as for natural aluminosilicates. Reversibility of sorption of caesium by natural glauconite and ferrocyanide sorbent was determined as caesium leaching degree from saturated samples. High caesium leaching rates and degrees are typical for natural glauconite irrespective of leachant salinity: total degree of leaching after 35 days of leaching was: mineral water = 63.4%, tap water = 41.6% and rain water = 28.8%. For

THE ROLE OF “INTEGRATED PRODUCTION” SCHEME IN THE NEW FRUIT AND VEGETABLE CMO: A TOOL FOR COMPETITIVENESS, SUSTAINABILITY OR OLIGOPSONY BY LARGE RETAIL CHAINS?

OpenAIRE

Canali, Gabriele

2008-01-01

The new Common Market Organization (CMO) for the fruit and vegetable sector approved in 2007, continues to include sustainability and competitiveness of the sector among its most important goals. The key role of the new (as well as the old) CMO is still played by Producers Organizations (POs): among other things, they should help farmers to organize and to concentrate supply in order to satisfy the old and new requests by large retailers in Europe as well as in other foreign markets. On the o...

Obtaining fruit and vegetables for the lowest prices: pricing survey of different outlets and geographical analysis of competition effects.

Science.gov (United States)

Pearson, Amber L; Winter, Pieta R; McBreen, Ben; Stewart, Georgia; Roets, Rianda; Nutsford, Daniel; Bowie, Christopher; Donnellan, Niamh; Wilson, Nick

2014-01-01

Inadequate fruit and vegetable (F&V) consumption is an important dietary risk factor for disease internationally. High F&V prices can be a barrier to dietary intake and so to improve understanding of this topic we surveyed prices and potential competition between F&V outlet types. Over a three week early autumn period in 2013, prices were collected bi-weekly for 18 commonly purchased F&Vs from farmers' markets (FM) selling local produce (n = 3), other F&V markets (OFVM) (n = 5), supermarkets that neighbored markets (n = 8), and more distant supermarkets (n = 8), (in urban Wellington and Christchurch areas of New Zealand). Prices from an online supermarket were also collected. A total of 3120 prices were collected. Most F&Vs (13/18) were significantly cheaper at OFVMs than supermarkets. Over half of the F&Vs (10/18) were significantly cheaper at nearby compared to distant supermarkets, providing evidence of a moderate 'halo effect' in price reductions in supermarkets that neighbored markets. Weekend (vs midweek) prices were also significantly cheaper at nearby (vs distant) supermarkets, supporting evidence for a 'halo effect'. Ideal weekly 'food basket' prices for a two adult, two child family were: OFVMs (NZ$76), online supermarket ($113), nearby supermarkets ($124), distant supermarkets ($127), and FMs ($138). This represents a savings of $49 per week (US$26) by using OFVMs relative to (non-online) supermarkets. Similarly, a shift from non-online supermarkets to the online supermarket would generate a $13 saving. In these locations general markets appear to be providing some substantially lower prices for fruit and vegetables than supermarkets. They also appear to be depressing prices in neighboring supermarkets. These results, when supplemented by other needed research, may help inform the case for interventions to improve access to fruit and vegetables, particularly for low-income populations.

Obtaining fruit and vegetables for the lowest prices: pricing survey of different outlets and geographical analysis of competition effects.

Directory of Open Access Journals (Sweden)

Amber L Pearson

Full Text Available AIMS: Inadequate fruit and vegetable (F&V consumption is an important dietary risk factor for disease internationally. High F&V prices can be a barrier to dietary intake and so to improve understanding of this topic we surveyed prices and potential competition between F&V outlet types. METHODS: Over a three week early autumn period in 2013, prices were collected bi-weekly for 18 commonly purchased F&Vs from farmers' markets (FM selling local produce (n = 3, other F&V markets (OFVM (n = 5, supermarkets that neighbored markets (n = 8, and more distant supermarkets (n = 8, (in urban Wellington and Christchurch areas of New Zealand. Prices from an online supermarket were also collected. RESULTS: A total of 3120 prices were collected. Most F&Vs (13/18 were significantly cheaper at OFVMs than supermarkets. Over half of the F&Vs (10/18 were significantly cheaper at nearby compared to distant supermarkets, providing evidence of a moderate 'halo effect' in price reductions in supermarkets that neighbored markets. Weekend (vs midweek prices were also significantly cheaper at nearby (vs distant supermarkets, supporting evidence for a 'halo effect'. Ideal weekly 'food basket' prices for a two adult, two child family were: OFVMs (NZ$76, online supermarket ($113, nearby supermarkets ($124, distant supermarkets ($127, and FMs ($138. This represents a savings of $49 per week (US$26 by using OFVMs relative to (non-online supermarkets. Similarly, a shift from non-online supermarkets to the online supermarket would generate a $13 saving. CONCLUSIONS: In these locations general markets appear to be providing some substantially lower prices for fruit and vegetables than supermarkets. They also appear to be depressing prices in neighboring supermarkets. These results, when supplemented by other needed research, may help inform the case for interventions to improve access to fruit and vegetables, particularly for low-income populations.

Establishment of vegetation on mined sites by management of mycorrhizae

International Nuclear Information System (INIS)

Marrs, L.F.; Marx, D.H.; Cordell, C.E.

1999-01-01

Plant ecosystems, including those in the tropical, temperate, boreal, and desert zones, began evolving more than 400 million years ago. Trees and other land plants in these environments were faced with many natural stresses including extreme temperature changes, fluctuating levels of available water, soil infertility, catastrophic fires and storms, poor soil physical conditions and competition. Basically, these plants evolved by genetic selection and developed many physical, chemical, and biological requirements necessary to survive these periodically stressed environments. Survivors were those that could form extensive lateral root systems to occupy soil volumes sufficiently large for them to obtain enough essential mineral elements and water to support their above and below ground growth needs. The most competitive plants in these stressed ecosystems were those with the largest root systems. One major biological requirement that evolved was the association of plants with mycorrhizal fungi. This is still true today for land that has been disturbed by mining, construction, and other activities. Successful vegetation establishment on these lands has been achieved by using the biological tools; native tree seedlings, shrubs, forbs, and grasses inoculated with specific, beneficial mycorrhizal fungi. Trees and shrubs are custom grown in nurseries with selected mycorrhizal fungi, such as Pisolithus tinctorius (Pt) and other fungi, provide significant benefits to the plants through increased water and mineral adsorption, decreased toxin absorption and overall reduction of plant stress. This has resulted in significant increases in plant growth and survival rates, density and sustainable vegetation

[Correlation analysis on normalized difference vegetation index (NDVI) of different vegetations and climatic factors in Southwest China].

Science.gov (United States)

Zhang, Yuan-Dong; Zhang, Xiao-He; Liu, Shi-Rong

2011-02-01

Based on the 1982-2006 NDVI remote sensing data and meteorological data of Southwest China, and by using GIS technology, this paper interpolated and extracted the mean annual temperature, annual precipitation, and drought index in the region, and analyzed the correlations of the annual variation of NDVI in different vegetation types (marsh, shrub, bush, grassland, meadow, coniferous forest, broad-leaved forest, alpine vegetation, and cultural vegetation) with corresponding climatic factors. In 1982-2006, the NDVI, mean annual temperature, and annual precipitation had an overall increasing trend, and the drought index decreased. Particularly, the upward trend of mean annual temperature was statistically significant. Among the nine vegetation types, the NDVI of bush and mash decreased, and the downward trend was significant for bush. The NDVI of the other seven vegetation types increased, and the upward trend was significant for coniferous forest, meadow, and alpine vegetation, and extremely significant for shrub. The mean annual temperature in the areas with all the nine vegetation types increased significantly, while the annual precipitation had no significant change. The drought index in the areas with marsh, bush, and cultural vegetation presented an increasing trend, that in the areas with meadow and alpine vegetation decreased significantly, and this index in the areas with other four vegetation types had an unobvious decreasing trend. The NDVI of shrub and coniferous forest had a significantly positive correlation with mean annual temperature, and that of shrub and meadow had significantly negative correlation with drought index. Under the conditions of the other two climatic factors unchanged, the NDVI of coniferous forest, broad-leaved forest, and alpine vegetation showed the strongest correlation with mean annual temperature, that of grass showed the strongest correlation with annual precipitation, and the NDVI of mash, shrub, grass, meadow, and cultural

Self-organization, scaling and collapse in a coupled automaton model of foragers and vegetation resources with seed dispersal

International Nuclear Information System (INIS)

Boyer, D; Lopez-Corona, O

2009-01-01

We introduce a model of travelling agents (e.g., frugivorous animals) who feed on randomly located vegetation patches and disperse their seeds, thus modifying the spatial distribution of the resources in the long term. It is assumed that the survival probability of a seed increases with the distance to its parent patch and decreases with the size of the colonized patch. In turn, the foraging agents use a deterministic strategy with memory that makes them visit the largest possible patches accessible within minimal travelling distances. The combination of these interactions produce complex spatio-temporal patterns. If the patches have a small initial size, the vegetation total mass (biomass) increases with time and reaches a maximum corresponding to a self-organized critical state with power-law-distributed patch sizes and Levy-like movement patterns for the foragers. However, this state collapses as the biomass sharply decreases to reach a noisy stationary regime characterized by corrections to scaling. In systems with low plant competition, the efficiency of the foraging rules leads to the formation of heterogeneous vegetation patterns with 1/f α frequency spectra, and contributes, rather counter-intuitively, to lower the biomass levels.

Effects of vegetation structure on biomass accumulation in a Balanced Optimality Structure Vegetation Model (BOSVM v1.0

Directory of Open Access Journals (Sweden)

Z. Yin

2014-05-01

Full Text Available A myriad of interactions exist between vegetation and local climate for arid and semi-arid regions. Vegetation function, structure and individual behavior have large impacts on carbon–water–energy balances, which consequently influence local climate variability that, in turn, feeds back to the vegetation. In this study, a conceptual vegetation structure scheme is formulated and tested in the new Balanced Optimality Structure Vegetation Model (BOSVM to explore the importance of vegetation structure and vegetation adaptation to water stress on equilibrium biomass states. Surface energy, water and carbon fluxes are simulated for a range of vegetation structures across a precipitation gradient in West Africa and optimal vegetation structures that maximize biomass for each precipitation regime are determined. Two different strategies of vegetation adaptation to water stress are included. Under dry conditions vegetation tries to maximize the water use efficiency and leaf area index as it tries to maximize carbon gain. However, a negative feedback mechanism in the vegetation–soil water system is found as the vegetation also tries to minimize its cover to optimize the surrounding bare ground area from which water can be extracted, thereby forming patches of vertical vegetation. Under larger precipitation, a positive feedback mechanism is found in which vegetation tries to maximize its cover as it then can reduce water loss from bare soil while having maximum carbon gain due to a large leaf area index. The competition between vegetation and bare soil determines a transition between a "survival" state to a "growing" state.

Economics of small-scale on-farm use of canola and soybean for biodiesel and straight vegetable oil biofuels

International Nuclear Information System (INIS)

Fore, Seth R.; Porter, Paul; Jordan, Nicholas; Lazarus, William

2011-01-01

While the cost competitiveness of vegetable oil-based biofuels (VOBB) has impeded extensive commercialization on a large-scale, the economic viability of small-scale on-farm production of VOBB is unclear. This study assessed the cost competitiveness of small-scale on-farm production of canola- [Brassica napus (L.)] and soybean-based [Glycine max (L.)] biodiesel and straight vegetable oil (SVO) biofuels in the upper Midwest at 2007 price levels. The effects of feedstock type, feedstock valuation (cost of production or market price), biofuel type, and capitalization level on the cost L -1 of biofuel were examined. Valuing feedstock at the cost of production, the cost of canola-based biodiesel ranged from 0.94 to 1.13 L -1 and SVO from 0.64 to 0.83 L -1 depending on capitalization level. Comparatively, the cost of soybean-based biodiesel and SVO ranged from 0.40 to 0.60 L -1 and from 0.14 to 0.33 L -1 , respectively, depending on capitalization level. Valuing feedstock at the cost of production, soybean biofuels were cost competitive whereas canola biofuels were not. Valuing feedstock at its market price, canola biofuels were more cost competitive than soybean-based biofuels, though neither were cost competitive with petroleum diesel. Feedstock type proved important in terms of the meal co-product credit, which decreased the cost of biodiesel by 1.39 L -1 for soybean and 0.44 L -1 for canola. SVO was less costly to produce than biodiesel due to reduced input costs. At a small scale, capital expenditures have a substantial impact on the cost of biofuel, ranging from 0.03 to 0.25 L -1 . (author)

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.

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

Effects of increasing and decreasing physiological arousal on anticipation timing performance during competition and practice.

Science.gov (United States)

Duncan, Michael J; Smith, Mike; Bryant, Elizabeth; Eyre, Emma; Cook, Kathryn; Hankey, Joanne; Tallis, Jason; Clarke, Neil; Jones, Marc V

2016-01-01

The aim of this study was to investigate if the effects of changes in physiological arousal on timing performance can be accurately predicted by the catastrophe model. Eighteen young adults (8 males, 10 females) volunteered to participate in the study following ethical approval. After familiarisation, coincidence anticipation was measured using the Bassin Anticipation Timer under four incremental exercise conditions: Increasing exercise intensity and low cognitive anxiety, increasing exercise intensity and high cognitive anxiety, decreasing exercise intensity and low cognitive anxiety and decreasing exercise intensity and high cognitive anxiety. Incremental exercise was performed on a treadmill at intensities of 30%, 50%, 70% and 90% heart rate reserve (HRR) respectively. Ratings of cognitive anxiety were taken at each intensity using the Mental Readiness Form 3 (MRF3) followed by performance of coincidence anticipation trials at speeds of 3 and 8 mph. Results indicated significant condition × intensity interactions for absolute error (AE; p = .0001) and MRF cognitive anxiety intensity scores (p = .05). Post hoc analysis indicated that there were no statistically significant differences in AE across exercise intensities in low-cognitive anxiety conditions. In high-cognitive anxiety conditions, timing performance AE was significantly poorer and cognitive anxiety higher at 90% HRR, compared to the other exercise intensities. There was no difference in timing responses at 90% HRR during competitive trials, irrespective of whether exercise intensity was increasing or decreasing. This study suggests that anticipation timing performance is negatively affected when physiological arousal and cognitive anxiety are high.

Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species.

Energy Technology Data Exchange (ETDEWEB)

T.B. Harrington; C.M. Dagley; M.B. Edwards.

2003-10-01

Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition and needlefall from overstory pines on understory plant performance. Three 13- to 15-yr-old plantations near Aiken, SC, were thinned to 0, 25, 50, or 100% of nonthinned basal area (19.5 m2 ha-1). Combinations of trenching (to eliminate root competition) and needlefall were applied to areas within each plot, and containerized seedlings of 14 perennial herbaceous species and longleaf pine were planted within each. Overstory crown closure ranged from 0 to 81%, and soil water and available nitrogen varied consistently with pine stocking, trenching, or their combination. Cover of planted species decreased an average of 16.5 and 14.1% as a result of above- and below-ground competition, respectively. Depending on species, needlefall effects were positive, negative, or negligible. Results indicate that understory restoration will be most successful when herbaceous species are established within canopy openings (0.1-0.2 ha) managed to minimize negative effects from above- and belowground competition and needlefall.

Municipal Competition for Inhabitants under Population Decrease. Zusammenfassung: Kommunale Konkurrenz um Einwohner bei Bevölkerungsrückgang

Directory of Open Access Journals (Sweden)

Peter Friedrich

2014-12-01

Full Text Available The shrinking population during the break-down, adaptation and recovery phase in Estonian social and political development enforces municipal competition among the municipalities. Competition for inhabitants is embedded in regional competition showing horizontal and vertical competition relations. Inhabitants’ competition prevails indirectly through municipal business promotion competition and directly through competition for inhabitants. The competition shows three phases. A phase concerns zoning and long-term planning; a second one refers to negotiations with settlement firms and short-term actions to attract inhabitants followed by a phase of revisions of zoning and measures. The oligopolistic industrial zoning model of business promotion policy points to the consequences of horizontal municipal competition also on population. Vertical influences on business promotion policy demonstrate a game-theoretic example of intergovernmental intervention from higher government on zoning. The negotiation phase in business promotion policy is modelled by a bilateral monopoly model between a municipality and a settlement firm. Horizontal regional competition highlights the implications on inhabitants’ competition. An oligopoly model of direct inhabitant competition concerns the zoning in particular for housing. Furthermore, a model of public enterprise service and fee formation and of horizontal public firm competition shows inhabitants’ competition in the second phase. Forms of inhabitant competition concerning suburbanisation and using public debt, revenues such as taxes, fees and expenditures are mentioned. Finally, follows a discussion of possible instruments to regulate inhabitant competition.

First Brazilian patent for dielectric vegetable oil for transformers; Primeira patente brasileira de oleo dieletrico vegetal para transformadores

Energy Technology Data Exchange (ETDEWEB)

Carioca, Jose O.B.; Carvalho, Paulo C.M.; Correa, Raimundo G.C.; Bernardo, Francisco A.B. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Coelho Junior, Luiz G. [2 Companhia Energetica do Ceara (COELCE), Fortaleza, CE (Brazil); Abreu, Rosa F.A. [Universidade Estadual do Ceara (UECE), Fortaleza, CE (Brazil)

2008-07-01

The present paper discuss the development of different insulating oils for electric power transformers during the last hundred years and analyze comparatively the potential for the use of vegetable oils as a source for green dielectric oils, due to its high level of biodegradability, nontoxic, material compatibility, good electric strength and insulation properties, long-term oxidative and thermal stability, relatively low pour point and reasonable cost. Based on these premises, the authors developed a new type of insulating fluid based on Brazilian vegetable oils never used before for this purpose. This product is competitive with similar and patented products developed from canola and soya vegetable oils. Recently a new patent related with the process for the production of this fluid was submitted to the World Industrial Property Organization - WIPO. (author)

Economics of small-scale on-farm use of canola and soybean for biodiesel and straight vegetable oil biofuels

Energy Technology Data Exchange (ETDEWEB)

Fore, Seth R.; Porter, Paul; Jordan, Nicholas [Department of Agronomy and Plant Genetics, 1991 Upper Buford Circle, Borlaug 411, The University of Minnesota, Saint Paul, Minnesota 55108 (United States); Lazarus, William [Department of Applied Economics, 231 Classroom Office Building, 1994 Buford Avenue, The University of Minnesota, Saint Paul, Minnesota 55108 (United States)

2011-01-15

While the cost competitiveness of vegetable oil-based biofuels (VOBB) has impeded extensive commercialization on a large-scale, the economic viability of small-scale on-farm production of VOBB is unclear. This study assessed the cost competitiveness of small-scale on-farm production of canola- [Brassica napus (L.)] and soybean-based [Glycine max (L.)] biodiesel and straight vegetable oil (SVO) biofuels in the upper Midwest at 2007 price levels. The effects of feedstock type, feedstock valuation (cost of production or market price), biofuel type, and capitalization level on the cost L{sup -1} of biofuel were examined. Valuing feedstock at the cost of production, the cost of canola-based biodiesel ranged from 0.94 to 1.13 L{sup -1} and SVO from 0.64 to 0.83 L{sup -1} depending on capitalization level. Comparatively, the cost of soybean-based biodiesel and SVO ranged from 0.40 to 0.60 L{sup -1} and from 0.14 to 0.33 L{sup -1}, respectively, depending on capitalization level. Valuing feedstock at the cost of production, soybean biofuels were cost competitive whereas canola biofuels were not. Valuing feedstock at its market price, canola biofuels were more cost competitive than soybean-based biofuels, though neither were cost competitive with petroleum diesel. Feedstock type proved important in terms of the meal co-product credit, which decreased the cost of biodiesel by 1.39 L{sup -1} for soybean and 0.44 L{sup -1} for canola. SVO was less costly to produce than biodiesel due to reduced input costs. At a small scale, capital expenditures have a substantial impact on the cost of biofuel, ranging from 0.03 to 0.25 L{sup -1}. (author)

Competition along productivity gradients: news from heathlands.

Science.gov (United States)

Delerue, Florian; Gonzalez, Maya; Achat, David L; Puzos, Luc; Augusto, Laurent

2018-05-01

The importance of competition in low productive habitats is still debated. Studies which simultaneously evaluate preemption of resources and consequences for population dynamics are needed for a comprehensive view of competitive outcomes. We cultivated two emblematic species of European heathlands (Calluna vulgaris and Molinia caerulea) in a nursery for 2 years at two fertility levels, reproducing the productivity gradient found in phosphorus (P)-depleted heathlands in southwest France. The second year, we planted Ulex europaeus seedlings, a ubiquitous heathland species, under the cover of the two species to evaluate its ability to regenerate. Half of the seedlings were placed in tubes for exclusion of competitor roots. We measured the development of the competitors aboveground and belowground and their interception of resources (light, water, inorganic P). Ulex seedlings' growth and survival were also measured. Our results on resources interception were consistent with species distribution in heathlands. Molinia, which dominates rich heathlands, was the strongest competitor for light and water in the rich soil. Calluna, which dominates poor heathlands, increased its root allocation in the poor soil, decreasing water and inorganic P availability. However, the impact of total competition and root competition on Ulex seedlings decreased in the poor soil. Other mechanisms, especially decrease of water stress under neighbouring plant cover, appeared to have more influence on the seedlings' response. We found no formal contradiction between Tilman and Grime's theories. Root competition has a primary role in acquisition of soil resources in poor habitats. However, the importance of competition decreases with decreasing fertility.

Exploring an Age Difference in Preschool Children's Competitiveness Following a Competition.

Science.gov (United States)

Hu, Yu; Zhu, Yi

2018-01-01

Literature suggests that resource acquisition compels competition in young children. However, little is still known about the development of preschool children's competitiveness. In this preliminary study, 166 children (aged 2-4 and 5-6 years) engaged in a dyadic competition which resulted in a winning and a losing group (in a control/non-competition group, participants engaged in a similar task which did not lead to winning/losing outcome), and then experimenters tracked their decisions to compete again with a rival (i.e., an individual they interacted in the previous competition task) and a non-rival competitor (i.e., an anonymous classmate they did not interact in the previous competition task) for a reward, respectively. As expected, results showed an age-related decreasing trend in the percentage of choices to compete with a competitor. However, this age difference was only significant in the control group when participants played with the partner with whom they interacted in the previous game and in the losing group when participants competed with a non-rival competitor. This study contributes to our knowledge of how competitiveness develop in preschool childhood, and calls for further research on the roles of motivation and cognitive control in children's competitiveness.

Hiding vegetables to reduce energy density: an effective strategy to increase children's vegetable intake and reduce energy intake.

Science.gov (United States)

Spill, Maureen K; Birch, Leann L; Roe, Liane S; Rolls, Barbara J

2011-09-01

Strategies are needed to increase children's intake of a variety of vegetables, including vegetables that are not well liked. We investigated whether incorporating puréed vegetables into entrées to reduce the energy density (ED; in kcal/g) affected vegetable and energy intake over 1 d in preschool children. In this crossover study, 3- to 5-y-old children (n = 40) were served all meals and snacks 1 d/wk for 3 wk. Across conditions, entrées at breakfast, lunch, dinner, and evening snack were reduced in ED by increasing the proportion of puréed vegetables. The conditions were 100% ED (standard), 85% ED (tripled vegetable content), and 75% ED (quadrupled vegetable content). Entrées were served with unmanipulated side dishes and snacks, and children were instructed to eat as much as they liked. The daily vegetable intake increased significantly by 52 g (50%) in the 85% ED condition and by 73 g (73%) in the 75% ED condition compared with that in the standard condition (both P daily energy intake decreased by 142 kcal (12%) from the 100% to 75% ED conditions (P daily vegetable intake and decrease the energy intake in young children. This trial was registered at clinicaltrials.gov as NCT01252433.

New options for conversion of vegetable oils to alternative fuels

Energy Technology Data Exchange (ETDEWEB)

Demirbas, A.; Kara, H. [Selcuk University, Konya (Turkey). Department of Chemical Engineering

2006-05-15

Biodiesel from transesterification of vegetable oils is an excellent alternative fuel. There is, however, a need to develop a direct process for conversion of vegetable oils into gasoline-competitive biodiesel and other petroleum products. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The purpose of the transesterification process is to lower the viscosity of vegetable oil. Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, whereas methyl esters of vegetable oils are slightly more viscous. The methyl esters are more volatile than those of the vegetable oils. Conversion of vegetable oils to useful fuels involves the pyrolysis and catalytic cracking of the oils into lower molecular products. Pyrolysis produces more biogasoline than biodiesel fuel. Soap pyrolysis products of vegetable oils can be used as alternative diesel engine fuel. The soaps obtained from the vegetable oils can be pyrolyzed into hydrocarbon-rich products. Zinc chloride catalyst contributed greatly to high amounts of hydrocarbons in the liquid product. The yield of ZnCl2 catalytic conversion of the soybean oil reached the maximum 79.9% at 660 K. (author)

Technical solutions to make biofuels more competitive

International Nuclear Information System (INIS)

Anon.

2006-01-01

With the present day environmental and economical stakes, the French government has announced in 2005 a plan for the accelerated development of biofuels. In France, two traditional ways of biofuel generation exist: the bio-ethanol way and the bio-diesel way (methyl esters of vegetable oils). Two problems limit today the development of biofuels: the available cultivation surfaces and the production costs. The challenge of the next generation of biofuels concerns the better use of the available biomass, with no competition with the food productions, and in particular the development of ethyl esters of vegetable oils or the hydrogen processing of vegetable oils. Other processes are making their way, like the biomass to liquid (BTL) process, based on the Fischer-Tropsch synthesis, which allows to convert any type of biomass source into liquid fuels with a high production rate (about 5000 l/Ha). Short paper. (J.S.)

Mechanisms of herbaceous vegetation restoration successions

Science.gov (United States)

Pankratova, Lubov

2017-04-01

The vegetation dynamics study is an important sector of research in phytocenology. The changing vegetation mechanisms' studying with the purpose of forecasting and management processes is an urgent theoretical and practical task. We consider succession as successive series of composition changes and phytocenoses structure caused by internal reasons and external ones. In this case, we are dealing with natural, secondary and progressive successions. The rapid sequential change of associations aimed at restoring coenotic environment and not resulting in ecogenesis stage changes is called demattia. Fully restored coenotic environment corresponds to vegetation sublimation. The way to this most stable state goes via a number of derived associations, each of them can be seen as long phytocenotic sustainable phenomenon, but different in time. The ability of living beings to reproduce in one way or another, their spreading, filling the space and confrontation to adverse conditions presents an important preservation mechanism and biodiversity increase, as well as its sustainability. The bio-diversity indicator is very significant for stability maintainment and phytocenosis estimation. Succession mechanisms classification provides three categories of relationships between organisms in the successional series: model relief or stimulation corresponds to the phase of endoecological succession which means that early settlers in their activities change the environment, making it available for the next wave of colonists. The model of tolerance manifests itself in the form of competitive relationships, resulting in selection of more competitive species with a pronounced feature S. According to the inhibition model, all types of community are able to colonize open spaces, they are resistant to competitors invasion, but the later species are able to inhabit and increase their number only after the loss of any of the predecessors. The predecessors change environment settings making it

Impact of Competition on Mutual Fund Marketing Expenses

Directory of Open Access Journals (Sweden)

Sitikantha Parida

2018-03-01

Full Text Available In this paper, I study the impact of market competition on mutual fund marketing expenses. In a sample of US domestic equity mutual funds, I find that marketing expenses decrease with the competition. This effect is stronger for top-performing funds. These results are counterintuitive, as one would ordinarily expect funds to incur more marketing expenses in response to pressure from competing funds. However, these results support the narrative that mutual funds employ marketing to draw attention to their performance in a tournament-like market, where the top-performing funds (the winners are rewarded with disproportionately high new investments. Higher competition decreases the chances of each fund to outperform the others and adversely affect their ability to attract new investments, and the funds respond by decreasing marketing expenses. Thus, competition appears to have implications for investor search cost.

Exploring an Age Difference in Preschool Children’s Competitiveness Following a Competition

Directory of Open Access Journals (Sweden)

Yu Hu

2018-03-01

Full Text Available Literature suggests that resource acquisition compels competition in young children. However, little is still known about the development of preschool children’s competitiveness. In this preliminary study, 166 children (aged 2–4 and 5–6 years engaged in a dyadic competition which resulted in a winning and a losing group (in a control/non-competition group, participants engaged in a similar task which did not lead to winning/losing outcome, and then experimenters tracked their decisions to compete again with a rival (i.e., an individual they interacted in the previous competition task and a non-rival competitor (i.e., an anonymous classmate they did not interact in the previous competition task for a reward, respectively. As expected, results showed an age-related decreasing trend in the percentage of choices to compete with a competitor. However, this age difference was only significant in the control group when participants played with the partner with whom they interacted in the previous game and in the losing group when participants competed with a non-rival competitor. This study contributes to our knowledge of how competitiveness develop in preschool childhood, and calls for further research on the roles of motivation and cognitive control in children’s competitiveness.

Exploring an Age Difference in Preschool Children’s Competitiveness Following a Competition

Science.gov (United States)

Hu, Yu; Zhu, Yi

2018-01-01

Literature suggests that resource acquisition compels competition in young children. However, little is still known about the development of preschool children’s competitiveness. In this preliminary study, 166 children (aged 2–4 and 5–6 years) engaged in a dyadic competition which resulted in a winning and a losing group (in a control/non-competition group, participants engaged in a similar task which did not lead to winning/losing outcome), and then experimenters tracked their decisions to compete again with a rival (i.e., an individual they interacted in the previous competition task) and a non-rival competitor (i.e., an anonymous classmate they did not interact in the previous competition task) for a reward, respectively. As expected, results showed an age-related decreasing trend in the percentage of choices to compete with a competitor. However, this age difference was only significant in the control group when participants played with the partner with whom they interacted in the previous game and in the losing group when participants competed with a non-rival competitor. This study contributes to our knowledge of how competitiveness develop in preschool childhood, and calls for further research on the roles of motivation and cognitive control in children’s competitiveness. PMID:29593610

Is healthy competition healthy? New evidence of the impact of hospital competition.

Science.gov (United States)

Gift, Thomas L; Arnould, Richard; DeBrock, Larry

2002-01-01

Competition among hospitals is commonly regarded as inefficient due to the medical arms race phenomenon, but most evidence for this hypothesis predates the Medicare prospective payment system and preferred provider legislation. Recent studies indicate hospital competition reduces costs and prices, but nearly all such research has focused on California. We add to the body of literature that analyzes the effects of competition in hospital markets. Using data from the state of Washington, we show that hospitals assume more risk in competitive markets by being more likely to accept prospective payment arrangements with insurers. If the arrangement is retrospective, the hospital is more likely to offer a discount as the number of competing hospitals increases. Both findings indicate that competitive forces operate the same in hospital markets as in most others: as the number of competitors increases, prices decrease and market power shifts from the suppliers to purchasers. The medical arms race hypothesis that favors more concentrated hospital markets no longer appears to be valid.

CO2 leakage-induced vegetation decline is primarily driven by decreased soil O2.

Science.gov (United States)

Zhang, Xueyan; Ma, Xin; Zhao, Zhi; Wu, Yang; Li, Yue

2016-04-15

To assess the potential risks of carbon capture and storage (CCS), studies have focused on vegetation decline caused by leaking CO2. Excess soil CO2 caused by leakage can affect soil O2 concentrations and soil pH, but how these two factors affect plant development remains poorly understood. This hinders the selection of appropriate species to mitigate potential negative consequences of CCS. Through pot experiments, we simulated CO2 leakage to examine its effects on soil pH and soil O2 concentrations. We subsequently assessed how maize growth responded to these changes in soil pH and O2. Decreased soil O2 concentrations significantly reduced maize biomass, and explained 69% of the biomass variation under CO2 leakage conditions. In contrast, although leaked CO2 changed soil pH significantly (from 7.32 to 6.75), it remained within the optimum soil pH range for maize growth. This suggests that soil O2 concentration, not soil pH, influences plant growth in these conditions. Therefore, in case of potential CO2 leakage risks, hypoxia-tolerant species should be chosen to improve plant survival, growth, and yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

Status of biological control in vegetation management in forestry

Science.gov (United States)

George P. Markin; Donald E. Gardner

1993-01-01

Biological control traditionally depends upon importing the natural enemies of introduced weeds. Since vegetation management in forestry has primarily been aimed at protecting economic species of trees from competition from other native plants, biological control has been of little use in forestry. An alternative approach to controlling unwanted native plants,...

Simulation of fruit-set and trophic competition and optimization of yield advantages in six Capsicum cultivars using functional-structural plant modelling.

Science.gov (United States)

Ma, Y T; Wubs, A M; Mathieu, A; Heuvelink, E; Zhu, J Y; Hu, B G; Cournède, P H; de Reffye, P

2011-04-01

and vegetative sink strength on fruit-set and fruit weight. When the source-sink ratio at fruit-set decreased, the number of fruit retained on the plant increased competition for assimilates with vegetative organs. Therefore, total plant and vegetative dry weights decreased, especially for large-fruited cultivars. Optimization study showed that temporal heterogeneity of fruit-set and ripening was predicted to be reduced when fruits were harvested earlier. Furthermore, there was a 20 % increase in the number of extra fruit set.

The effect of swimming on oral health status: competitive versus non-competitive athletes

Directory of Open Access Journals (Sweden)

Simonetta D’ERCOLE

2016-04-01

Full Text Available ABSTRACT Young swimmers are particularly susceptible to the onset of oral diseases. Objective To evaluate the oral health status in young competitive and non-competitive swimmers, involving an assessment of salivary cariogenic bacteria and secretory IgA (S-IgA concentration. Material and Methods Before training sessions (T1, 54 competitive and 69 non-competitive swimmers had the following parameters assessed: decayed, missing, and filled teeth (DMFT, Plaque Index (PlI, and Gingival Index (GI. At T1 and after training sessions (T2, stimulated saliva was collected and microbiological and immunological analyses were performed. Results Competitive swimmers trained 2.02±0.09 hours 5 times a week, while non-competitive swimmers trained 2.03±0.18 hours a week. A total of 14.7% of competitive swimmers suffered dental trauma related to sports. Only 11.76% of the competitive swimmers took a daily dose of fluoride, against 32.65% of non-competitive swimmers (p=0.029. Neither group followed an established diet or presented statistically significant differences in terms of nutritional supplement drink and chocolate intake. There were statistically significant differences in terms of oral hygiene. No significant difference in clinical indexes (DMFT, PlI, and GI was present. S. mutans was harbored by 18.6% of competitive and the 32.2% of non-competitive swimmers. S. sobrinus was detected in 22.03% of competitive and 91.6% of non-competitive swimmers (p<0.05. S. sanguinis was found only in the saliva of competitive swimmers. The average S-IgA of competitive swimmers decreased significantly at T2 (p<0.05. The pool water had a daily average pH of 7.22. Conclusions Microbial markers, immune status and sporting characteristics are important for establishing guidelines for management of training load in order to minimize physical stress and the risk of oral infection.

Competition and Outsourcing with Scale Economies

OpenAIRE

Gérard P. Cachon; Patrick T. Harker

2002-01-01

Scale economies are commonplace in operations, yet because of analytical challenges, relatively little is known about how firms should compete in their presence. This paper presents a model of competition between two firms that face scale economies; (i.e., each firm's cost per unit of demand is decreasing in demand). A general framework is used, which incorporates competition between two service providers with price- and time-sensitive demand (a queuing game), and competition between two reta...

Development of direct competitive biomimetic immunosorbent assay based on quantum dot label for determination of trichlorfon residues in vegetables.

Science.gov (United States)

Liu, Qiurui; Jiang, Mingdi; Ju, Zeliang; Qiao, Xuguang; Xu, Zhixiang

2018-06-01

A direct competitive biomimetic immunosorbent assay method based on molecularly imprinted polymer was developed for the determination of trichlorfon. A CdSe/ZnS quantum dot label was used as the marker. The hydrophilic imprinted film was synthesized directly on the surface of a 96-well plate, and characterized by Fourier-transform infrared spectroscopy and thermo-gravimetric analyses. The method exhibited high stability, selectivity, and sensitivity. Under optimal conditions, the limits of detection and sensitivity of the biomimetic immunosorbent assay method were 9.0 μg L -1 and 5.0 mg L -1 (0.1 mg kg -1 and 62.5 mg kg -1 for vegetable sample), respectively. Low cross-reactivity values of 19.2% and 15.6% were obtained for the structural analogues. Spinach and rape samples spiked with trichlorfon were extracted and determined by this method with recoveries ranging from 83.6% to 91.1%. The method was applied for the detection of trichlorfon residues in leek and cucumber samples, and results correlated well with those obtained using GC. Copyright © 2018 Elsevier Ltd. All rights reserved.

Elephant movement closely tracks precipitation-driven vegetation dynamics in a Kenyan forest-savanna landscape.

Science.gov (United States)

Bohrer, Gil; Beck, Pieter Sa; Ngene, Shadrack M; Skidmore, Andrew K; Douglas-Hamilton, Ian

2014-01-01

This study investigates the ranging behavior of elephants in relation to precipitation-driven dynamics of vegetation. Movement data were acquired for five bachelors and five female family herds during three years in the Marsabit protected area in Kenya and changes in vegetation were mapped using MODIS normalized difference vegetation index time series (NDVI). In the study area, elevations of 650 to 1100 m.a.s.l experience two growth periods per year, while above 1100 m.a.s.l. growth periods last a year or longer. We find that elephants respond quickly to changes in forage and water availability, making migrations in response to both large and small rainfall events. The elevational migration of individual elephants closely matched the patterns of greening and senescing of vegetation in their home range. Elephants occupied lower elevations when vegetation activity was high, whereas they retreated to the evergreen forest at higher elevations while vegetation senesced. Elephant home ranges decreased in size, and overlapped less with increasing elevation. A recent hypothesis that ungulate migrations in savannas result from countervailing seasonally driven rainfall and fertility gradients is demonstrated, and extended to shorter-distance migrations. In other words, the trade-off between the poor forage quality and accessibility in the forest with its year-round water sources on the one hand and the higher quality forage in the low-elevation scrubland with its seasonal availability of water on the other hand, drives the relatively short migrations (the two main corridors are 20 and 90 km) of the elephants. In addition, increased intra-specific competition appears to influence the animals' habitat use during the dry season indicating that the human encroachment on the forest is affecting the elephant population.

Vegetation dynamics induced by phreatophyte--aquifer interactions.

Science.gov (United States)

Ridolfi, Luca; D'Odorico, Paolo; Laio, Francesco

2007-09-21

The dynamics of phreatophyte vegetation are strongly coupled to those of the shallow phreatic aquifers from which phreatophytes extract water. Vegetation is able to influence the depth of the water table, which, in turn, can induce stress in vegetation. These interactions are likely to affect the composition and structure of phreatophyte plant communities, as well as their successional dynamics. Despite the environmental and economical value of many wetland plant ecosystems around the world, the impact of vegetation-water table interactions on ecosystem succession and interspecies competition in phreatophyte plant communities remains poorly understood. This study develops a minimalistic modelling framework to investigate the dynamics of two phreatophyte species, and their interactions with the water table. In spite of its simplicity, the model exhibits a remarkable variety of dynamical behaviors, especially when the water table depth is forced by external drivers. It is shown that, even when one of the two species is dominant with respect to the other, these two species can coexist showing periodic, quasi-periodic, and chaotic dynamics. Moreover, in the presence of a random environmental forcing, noise-induced coexistence may emerge.

Effective ways of decrease in the maintenance of heavy metals in soils and vegetative production

International Nuclear Information System (INIS)

Komarova, N.A.; Komarov, V.I.; Grishina, A.V.; Akanova, N.I.

2008-01-01

Receptions detoxication of heavy metals and reception vegetative production adequating to sanitary-and-hygienic norms are developed and scientifically proved. Correlation dependence between pH, concentration of heavy metals in vegetative production and level of productivity of agricultural crops is established. The most essential factor reducing till 8-10 of time receipt in plants Cu, Cd, Zn and Pb, level of reaction of environment in soil is. Dynamics of migration of heavy metals from the soil polluted water-soluble form of heavy metals is investigated

Vegetation Response to Upper Pliocene Glacial/Interglacial Cyclicity in the Central Mediterranean

Science.gov (United States)

Combourieu-Nebout, Nathalie

1993-09-01

New detailed pollen analysis of the lower part of the Upper Pliocene Semaforo section (Crotone, Italy) documents cyclic behavior of vegetation at the beginning of the Northern Hemisphere glaciations. The competition between four vegetation units (subtropical humid forest, deciduous temperate forest, altitudinal coniferous forest, and open xeric assemblage) probably reflects modifications of vegetation belts at this montane site. Several increases in herbaceous open vegetation regularly alternate with subtropical humid forest, which expresses rapid climatic oscillations. The complete temporal succession—deciduous forest (rich in Quercus), followed by subtropical humid forest (Taxodiaceae and Cathaya), then altitudinal coniferous forest ( Tsuga, Cedrus, Abies, and Picea), and finally herbaceous open vegetation (Graminae, Compositae, and Artemisia )—displays the climatic evolution from warm and humid interglaciation to cold and dry glaciation. It also suggests an independent variation of temperature and humidity, the two main climatic parameters. The vegetation history of southern Calabria recorded in the Semaforo section have been correlated with the ∂ 18O signal established in the Atlantic Ocean.

Are Namibian "fairy circles" the consequence of self-organizing spatial vegetation patterning?

Directory of Open Access Journals (Sweden)

Michael D Cramer

Full Text Available Causes of over-dispersed barren "fairy circles" that are often surrounded by ca. 0.5 m tall peripheral grasses in a matrix of shorter (ca. 0.2 m tall grasses in Namibian grasslands remain mysterious. It was hypothesized that the fairy circles are the consequence of self-organizing spatial vegetation patterning arising from resource competition and facilitation. We examined the edaphic properties of fairy circles and variation in fairy circle size, density and landscape occupancy (% land surface with edaphic properties and water availability at a local scale (<50 km and with climate and vegetation characteristics at a regional scale. Soil moisture in the barren fairy circles declines from the center towards the periphery and is inversely correlated with soil organic carbon, possibly indicating that the peripheral grass roots access soil moisture that persists into the dry season within fairy circles. Fairy circle landscape occupancy is negatively correlated with precipitation and soil [N], consistent with fairy circles being the product of resource-competition. Regional fairy circle presence/absence is highly predictable using an empirical model that includes narrow ranges of vegetation biomass, precipitation and temperature seasonality as predictor variables, indicating that fairy circles are likely a climate-dependent emergent phenomenon. This dependence of fairy circle occurrence on climate explains why fairy circles in some locations may appear and disappear over time. Fairy circles are only over-dispersed at high landscape occupancies, indicating that inter-circle competition may determine their spacing. We conclude that fairy circles are likely to be an emergent arid-grassland phenomenon that forms as a consequence of peripheral grass resource-competition and that the consequent barren circle may provide a resource-reservoir essential for the survival of the larger peripheral grasses and provides a habitat for fossicking fauna.

Trade-off between light interception efficiency and light use efficiency: implications for species coexistence in one-sided light competition

NARCIS (Netherlands)

Onoda, Y.; Saluñga, J.B.; Akutsu, K.; Aiba, S.I.; Yahara, T.; Anten, N.P.R.

2014-01-01

1. Taller plant species can pre-empt solar energy and suppress growth of subordinate species in vegetation stands, which is described through one-sided competition. Yet, in much of the world’s vegetation species of different statures coexist. This study aims to clarify the mechanisms underlying this

Competitive (AP7) and non-competitive (MK-801) NMDA receptor antagonists differentially alter glucose utilization in rat cortex

International Nuclear Information System (INIS)

Clow, D.W.; Lee, S.J.; Hammer, R.P. Jr.

1991-01-01

The effects of D,L-2-amino-7-phosphonoheptanoic acid (AP7), a competitive N-methyl-D-aspartate (NMDA) receptor antagonist, and MK-801, a non-competitive NMDA receptor antagonist, on regional brain metabolism were studied in unanesthetized, freely moving rats by using the quantitative 14 C2-deoxyglucose autoradiographic procedure. AP7 (338 or 901 mg/kg) produced a dose-dependent decrease of metabolic activity throughout most of the regions studied including sensory, motor, and limbic cortices. In contrast, MK-801 (0.1 or 1.0 mg/kg) resulted in a dose-dependent decrease of metabolic activity in sensory cortices, and an increase in limbic regions such as the hippocampal stratum lacunosum moleculare and entorhinal cortex. MK-801 also produced a biphasic response in agranular motor cortex, whereby the low dose increased while the high dose decreased labeling. In addition, MK-801 produced heterogeneous effects on regional cerebral metabolism in sensory cortices. Metabolic activity decreased in layer IV relative to layer Va following MK-801 treatment in primary somatosensory (SI) and visual (VI) cortices, suggesting a shift in activity from afferent fibers innervating layer IV to those innervating layer Va. MK-801 administration also decreased metabolic activity in granular SI relative to dysgranular SI, and in VI relative to secondary visual cortex (VII), thus providing a relative sparing of activity in dysgranular SI and VII. Thus, the non-competitive NMDA receptor antagonist suppressed activity from extrinsic neocortical sources, enhancing relative intracortical activity and stimulating limbic regions, while the competitive NMDA antagonist depressed metabolic activity in all cortical regions

The Ecohydrologic Role of Coexistence and Competition in Semiarid Hillslopes

Science.gov (United States)

Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

2015-12-01

Through its influence on runoff and erosion-deposition processes, vegetation remarkably regulates different aspects of landscape dynamics. Here, the influence of different plant functional traits on the coexistence of different species in arid and semi-arid regions with patchy vegetation is investigated using an ecohydrology model. The model simulates coevolving changes in biomass patterns for two species, as well as overland flow and soil moisture dynamics. Vegetation patterns emerge as a result of facilitation (shading and infiltration) and competition mechanisms as well as varying seed dispersal strategies. The results show that the survival of only one species or the coexistence of both species not only strongly depends on environmental stresses, but also on differences in hillslope micro and macro topography. These vegetation patterns have very different hydrologic signatures and the potential to trigger remarkably different geomorphic responses. Based on these results we establish new hypothesis that will be used to further investigate the role of plant interspecific and intraspecific feedbacks on landscape coevolution processes.

Vegetation moderates impacts of tourism usage on bird communities along roads and hiking trails.

Science.gov (United States)

Wolf, Isabelle D; Hagenloh, Gerald; Croft, David B

2013-11-15

Bird communities inhabiting ecosystems adjacent to recreational tracks may be adversely affected by disturbance from passing tourism traffic, vehicle-related mortality, habitat alteration and modified biotic relationships such as the increase of strong competitors. This study investigated the effects of tourist usage of roads vs. hiking trails on bird communities in gorges of the Flinders Ranges, a popular South Australian tourist destination in the arid-lands. High tourist usage along roads decreased the individual abundance and species richness of birds relative to low usage trails. The decrease in species richness, though less pronounced, also occurred at high-usage sites along trails. Changes in the species response to recreational disturbance/impacts varied depending on the ecology of the species. Bigger, more competitive birds with a generalist diet were overrepresented at high-usage sites along roads and trails. Species using microhabitats in lower vegetation layers were more sensitive. However, structural and floristic complexity of vegetation was a more important factor influencing bird abundance than tourist usage. Sites with a better developed shrub and tree layer sustained higher species abundance and richer communities. Importantly, vegetation qualities moderated the negative effect of high usage on the individual abundance of birds along roads, to the extent that such an effect was absent at sites with the best developed shrub and tree layer. To protect avifauna along recreational tracks in arid-lands gorges, we recommend the closure of some gorges or sections for vehicle or any access. Further, open space particularly for camping needs to be minimized as it creates areas of high tourist usage with modified habitat that provides birds with little buffer from disturbance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Substitution or addition? How overweight and obese adults incorporate vegetables into their diet during a randomized controlled vegetable feeding trial

Science.gov (United States)

Objective: When attempting to eat healthier, individuals may add vegetables to their diet (addition) without changing other eating behaviors. Alternatively, individuals adding vegetables may decrease consumption of other foods (substitution). Distinguishing between the two means of incorporation of ...

Individualistic vs. Competitive Participation: The Effect on Intrinsic Motivation.

Science.gov (United States)

Jones, Brent M.; And Others

Studies investigating intrinsic motivation and competition have supported the view that competition decreases intrinsic motivation. More recent studies suggest that the specific outcome of a competition (a win or a loss) differentially affects intrinsic motivation by highlighting the informational rather than the controlling aspect of the reward…

Elasticity and competitiveness of Indonesia’s palm oil export in India market

Directory of Open Access Journals (Sweden)

Awan Setya Dewanta

2016-10-01

Full Text Available This study examines the elasticity and competitiveness of Indonsia’s palm oil export in the India market, 1990 -2014. The methods used are Error Correction Model (ECM and Revealed Comparative Advantage (RCA approach. The results shows that the price is inelastic in short-term but it is elastic in long-term. The income and exchange rate are elastic in the long-term. There is also a decline in competitiveness in the market India. These findings also demonstrate that palm oil is normal goods and can be easily substituted with the same products of other countries or other vegetable oils. It threatens the Indonesian palm oil competitiveness in the Indian market.

Vegetation

DEFF Research Database (Denmark)

Epstein, H.E.; Walker, D.A.; Bhatt, U.S.

2012-01-01

increased 20-26%. • Increasing shrub growth and range extension throughout the Low Arctic are related to winter and early growing season temperature increases. Growth of other tundra plant types, including graminoids and forbs, is increasing, while growth of mosses and lichens is decreasing. • Increases...... in vegetation (including shrub tundra expansion) and thunderstorm activity, each a result of Arctic warming, have created conditions that favor a more active Arctic fire regime....

Did Aboriginal vegetation burning affect the Australian summer monsoon?

Science.gov (United States)

Balcerak, Ernie

2011-08-01

For thousands of years, Aboriginal Australians burned forests, creating grasslands. Some studies have suggested that in addition to changing the landscape, these burning practices also affected the timing and intensity of the Australian summer monsoon. Different vegetation types can alter evaporation, roughness, and surface reflectivity, leading to changes in the weather and climate. On the basis of an ensemble of experiments with a global climate model, Notaro et al. conducted a comprehensive evaluation of the effects of decreased vegetation cover on the summer monsoon in northern Australia. They found that although decreased vegetation cover would have had only minor effects during the height of the monsoon season, during the premonsoon season, burning-induced vegetation loss would have caused significant decreases in precipitation and increases in temperature. Thus, by burning forests, Aboriginals altered the local climate, effectively extending the dry season and delaying the start of the monsoon season. (Geophysical Research Letters, doi:10.1029/2011GL047774, 2011)

Competition, salinity, and clonal growth in native and introduced irises.

Science.gov (United States)

Mopper, Susan; Wiens, Karen C; Goranova, Greta A

2016-09-01

Iris pseudacorus spread rapidly into North America after introduction from Europe in the 1800s and now co-occurs with native I. hexagona in freshwater Louisiana wetlands. Native irises support and interact with multiple trophic levels, whereas I. pseudacorus is classified an invasive pest because it grows aggressively, reduces biodiversity, and displaces native vegetation. Salinity levels are increasing in coastal wetlands worldwide. We examined how salt-stress affects competitive interactions between these conspecifics. We established a three-way full-factorial common-garden experiment that included species (I. pseudacorus, I. hexagona), competition (no competition, intraspecific competition, and interspecific competition), and salinity (0, 4, 8 parts per thousand NaCl), with six replicates per treatment. After 18 mo, Iris pseudacorus produced much more biomass than the native species did (F1, 92 = 71.5, P Interspecific competition did not affect the introduced iris, but biomass of the native was strongly reduced (competition × species interaction: F2, 95 = 76.7, P = 0.002). Salinity significantly reduced biomass of both species (F2, 92 = 21.8, P competitive advantage over the native, regardless of environmental salinity levels. Based on patterns in clonal reproduction, the introduced iris could potentially threaten native iris populations. We are currently investigating seed production and mortality during competition and stress because both clonal and sexual reproduction must be considered when predicting long-term population dynamics. © 2016 Botanical Society of America.

Effects of food processing on the radioactivity of vegetables and cereals

International Nuclear Information System (INIS)

Roussel-Debet, S.; Real, J.

1995-01-01

The decrease of radioactivity for 134 Cs, 85 Sr, 106 Ru, 57 Co, 110m Ag during food processing was measured. Washing and bleaching vegetables directly contaminated by a single aerosol deposit led to a radioactivity decrease (depending on the vegetable, the radionuclide and the time of deposition) up to 90% for caesium. The efficiency of these processes was less important when the vegetables were contaminated by root transfer, except for peeling of root vegetables. Canning of vegetables indirectly contaminated by caesium, strontium, cobalt and ruthenium, after paring and bleaching, was rather interesting with residual radioactivity varying from 30 to 50% for green beans and from 5 to 20% for carrots. Measurements of stable caesium and strontium in cereals before and after industrial processing showed an important activity decrease; retention factors varied from 0.1 to 0.2 for wheat milling and 0.1 to 0.4 for rice processing. (authors). 6 refs., 9 tabs., 1 figs

CONCEPTUAL APPROACH OF COMPETITIVENESS AND INTERDEPENDENCE BETWEEN COMPETITION AND COMPETITIVENESS

Directory of Open Access Journals (Sweden)

Tatiana GUTIUM

2017-11-01

Full Text Available This article is devoted to analysis of interdependence and correlation between competition and competitiveness, and competition’s consequences. The author analysed some authors’ visions on competitiveness, and common features between theories of competition and competitiveness. Using the synthetic indicator elaborated by author has been evaluated the competitiveness of domestic goods on the internal and external market. At the end of this article, the author has developed proposals to increase competitiveness.

Spatial and Temporal Variation in Primary Productivity (NDVI) of Coastal Alaskan Tundra: Decreased Vegetation Growth Following Earlier Snowmelt

Science.gov (United States)

Gamon, John A.; Huemmrich, K. Fred; Stone, Robert S.; Tweedie, Craig E.

2015-01-01

In the Arctic, earlier snowmelt and longer growing seasons due to warming have been hypothesized to increase vegetation productivity. Using the Normalized Difference Vegetation Index (NDVI) from both field and satellite measurements as an indicator of vegetation phenology and productivity, we monitored spatial and temporal patterns of vegetation growth for a coastal wet sedge tundra site near Barrow, Alaska over three growing seasons (2000-2002). Contrary to expectation, earlier snowmelt did not lead to increased productivity. Instead, productivity was associated primarily with precipitation and soil moisture, and secondarily with growing degree days, which, during this period, led to reduced growth in years with earlier snowmelt. Additional moisture effects on productivity and species distribution, operating over a longer time scale, were evident in spatial NDVI patterns associated with microtopography. Lower, wetter regions dominated by graminoids were more productive than higher, drier locations having a higher percentage of lichens and mosses, despite the earlier snowmelt at the more elevated sites. These results call into question the oft-stated hypothesis that earlier arctic growing seasons will lead to greater vegetation productivity. Rather, they agree with an emerging body of evidence from recent field studies indicating that early-season, local environmental conditions, notably moisture and temperature, are primary factors determining arctic vegetation productivity. For this coastal arctic site, early growing season conditions are strongly influenced by microtopography, hydrology, and regional sea ice dynamics, and may not be easily predicted from snowmelt date or seasonal average air temperatures alone. Our comparison of field to satellite NDVI also highlights the value of in-situ monitoring of actual vegetation responses using field optical sampling to obtain detailed information on surface conditions not possible from satellite observations alone.

Resource investments in reproductive growth proportionately limit investments in whole-tree vegetative growth in young olive trees with varying crop loads.

Science.gov (United States)

Rosati, Adolfo; Paoletti, Andrea; Al Hariri, Raeed; Morelli, Alessio; Famiani, Franco

2018-02-21

It has long been debated whether tree growth is source limited, or whether photosynthesis is adjusted to the actual sink demand, directly regulated by internal and environmental factors. Many studies support both possibilities, but no studies have provided quantitative data at the whole-tree level, across different cultivars and fruit load treatments. This study investigated the effect of different levels of reproductive growth on whole-tree biomass growth across two olive cultivars with different growth rates (i.e., Arbequina, slow-growing and Frantoio, fast-growing), over 2 years. Young trees of both cultivars were completely deflowered either in 2014, 2015, both years or never, providing a range of levels of cumulated reproductive growth over the 2 years. Total vegetative dry matter growth over the 2 years was assessed by destructive sampling (whole tree). Vegetative growth increased significantly less in fruiting trees, however, the total of vegetative and reproductive growth did not differ significantly for any treatment or cultivar. Vegetative growth over the 2 years was closely (R2 = 0.89) and inversely related to reproductive growth across all treatments and cultivars. When using data from 2015 only, the regression improved further (i.e., R2 = 0.99). When biomass was converted into grams of glucose equivalents, based on the chemical composition of the different parts, the results indicated that for every gram of glucose equivalent invested in reproductive growth, vegetative growth was reduced by 0.73-0.78 g of glucose equivalent. This indicates that competition for resources played a major role in determining tree growth, but also that photosynthesis was probably also enhanced at increasing fruit load (or downregulated at decreasing fruit load). The leaf area per unit of trunk cross sectional area increased with deflowering (i.e., decreased with reproductive growth), suggesting that water relations might have limited photosynthesis in deflowered plants

Economic requirements for competitive laser fusion power production

International Nuclear Information System (INIS)

Hogan, W.J.; Meier, W.R.

1986-01-01

An economic model of a laser fusion commercial power plant is used to identify the design and operating regimes of the driver, target and reaction chamber that will result in economic competitiveness with future fission and coal plants. The authors find that, for a plant with a net power of 1 GW/sub e/, the cost of the driver must be less than $0.4 to 0.6 B, and the recirculating power fraction must be less than 25%. Target gain improvements at low driver energy are the most beneficial but also the most difficult to achieve. The optimal driver energy decreases with increasing target technology. The sensitivity of the cost of electricity to variations in cost and performance parameters decreases with increasing target technology. If chamber pulse rates of a few Hz can be achieved, then gains of 80-100 are sufficient, and higher pulse rates do not help much. Economic competitiveness becomes more difficult with decreasing plant size. Finally, decreasing the cost of the balance of plant has the greatest beneficial effect on economic competitiveness

Loblolly pine seedling response to competition from exotic vs. native plants

Science.gov (United States)

Pedram Daneshgar; Shibu Jose; Craig Ramsey; Robin Collins

2006-01-01

A field study was conducted in Santa Rosa County, FL to test the hypothesis that an exotic understory would exert a higher degree of competition on tree seedling establishment and growth than native vegetation. The study site was a 60 ha cutover area infested with the invasive exotic cogongrass [Imperata cylindrica (L.) Raeusch.]. A completely...

Modeling biomass competition and invasion in a schematic wetland

Science.gov (United States)

Ursino, N.

2010-08-01

Plants growing along hydrologic gradients adjust their biomass allocation and distribution in response to interspecific competition. Furthermore, susceptibility of a community to invasion is to some extent mediated by differences in growth habit, including root architecture and canopy hight. With reference to the study of a schematic wetland, the aim of this paper is (1) to test, via numerical modeling, the capacity of native plants to counteract an alien dominant species and cause eco-hydrological shifts of the ecosystem by changing their growth habit (e.g. allocating biomass below ground and by so doing changing the evapotranspiration locally) and (2) to test the impact on biodiversity of management practices that alter nutrient supply. The results demonstrated that unique combinations of vegetation types characterized by different growth habits may lead to different vegetation patterns under the same hydrologic forcing, and additionally, the vegetation patterns may change in response to major hydrological shifts, which could be related to diverse wetland management and restoration practices.

Review of Alternative Management Options of Vegetable Crop Residues to Reduce Nitrate Leaching in Intensive Vegetable Rotations

Directory of Open Access Journals (Sweden)

Laura Agneessens

2014-12-01

Full Text Available Vegetable crop residues take a particular position relative to arable crops due to often large amounts of biomass with a N content up to 200 kg N ha−1 left behind on the field. An important amount of vegetable crops are harvested during late autumn and despite decreasing soil temperatures during autumn, high rates of N mineralization and nitrification still occur. Vegetable crop residues may lead to considerable N losses through leaching during winter and pose a threat to meeting water quality objectives. However, at the same time vegetable crop residues are a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to harness the full potential of vegetable crop residues. Two fundamentally different crop residue management strategies to reduce N losses during winter in intensive vegetable rotations are reviewed, namely (i on-field management options and modifications to crop rotations and (ii removal of crop residues, followed by a useful and profitable application.

Evolutionary Modeling Predicts a Decrease in Postcopulatory Sperm Viability as a Response to Increasing Levels of Sperm Competition

NARCIS (Netherlands)

Engqvist, Leif

Sperm competition has been found to have a strong influence on the evolution of many male and female reproductive traits. Theoretical models have shown that, with increasing levels of sperm competition, males are predicted to increase ejaculate investment, and there is ample empirical evidence

Endogenous, Imperfectly Competitive Business Cycles

DEFF Research Database (Denmark)

Whitta-Jacobsen, Hans Jørgen

We investigate how imperfect competition affects the occurrence and the properties of endogenous, rational expectations business cycles in an overlapping generations model with constant returns to scale in production. The model has explicit product and labor markets all characterized...... by monopolistic competition. An implicit assumption of barriers to entry justifies that the number of firms is fixed even when positive profits occur. It turns out that both market power of firms on the product markets and market power of unions on the labor markets make the occurrence of cycles more likely....... In particular, imperfect competition on the product markets and the positive profits associated with it may have the effect that there is a cycle even if the labor supply curve is increasing in the real-wage rate. For competitive cycles is required not only a decreasing labor supply curve, but a wage elasticity...

A New Ala-122-Asn Amino Acid Change Confers Decreased Fitness to ALS-Resistant Echinochloa crus-galli

Directory of Open Access Journals (Sweden)

Silvia Panozzo

2017-11-01

Full Text Available Gene mutations conferring herbicide resistance may cause pleiotropic effects on plant fitness. Knowledge of these effects is important for managing the evolution of herbicide-resistant weeds. An Echinochloa crus-galli population resistant to acetolactate synthase (ALS herbicides was collected in a maize field in north-eastern Italy and the cross-resistance pattern, resistance mechanism and fitness costs associated to mutant-resistant plants under field conditions in the presence or absence of intra-specific competition were determined. The study reports for the first time the Ala-122-Asn amino-acid change in the ALS gene that confers high levels of cross-resistance to all ALS inhibitors tested. Results of 3-year growth analysis showed that mutant resistant E. crus-galli plants had a delayed development in comparison with susceptible plants and this was registered in both competitive (3, 7, and 20 plants m-2 and non-competitive (spaced plants situations. The number of panicles produced by resistant plants was also lower (about 40% fewer panicles than susceptible plants under no-intraspecific competition. Instead, with the increasing competition level, the difference in panicle production at harvest time decreased until it became negligible at 20 plants m-2. Evaluation of total dry biomass as well as biomass allocation in vegetative parts did not highlight any difference between resistant and susceptible plants. Instead, panicle dry weight was higher in susceptible plants indicating that they allocated more biomass than resistant ones to the reproductive organs, especially in no-competition and in competition situations at lower plant densities. The different fitness between resistant and susceptible phenotypes suggests that keeping the infestation density as low as possible can increase the reproduction success of the susceptible phenotype and therefore contribute to lowering the ratio between resistant and susceptible alleles. If adequately

A New Ala-122-Asn Amino Acid Change Confers Decreased Fitness to ALS-Resistant Echinochloa crus-galli.

Science.gov (United States)

Panozzo, Silvia; Scarabel, Laura; Rosan, Valentina; Sattin, Maurizio

2017-01-01

Gene mutations conferring herbicide resistance may cause pleiotropic effects on plant fitness. Knowledge of these effects is important for managing the evolution of herbicide-resistant weeds. An Echinochloa crus-galli population resistant to acetolactate synthase (ALS) herbicides was collected in a maize field in north-eastern Italy and the cross-resistance pattern, resistance mechanism and fitness costs associated to mutant-resistant plants under field conditions in the presence or absence of intra-specific competition were determined. The study reports for the first time the Ala-122-Asn amino-acid change in the ALS gene that confers high levels of cross-resistance to all ALS inhibitors tested. Results of 3-year growth analysis showed that mutant resistant E. crus-galli plants had a delayed development in comparison with susceptible plants and this was registered in both competitive (3, 7, and 20 plants m -2 ) and non-competitive (spaced plants) situations. The number of panicles produced by resistant plants was also lower (about 40% fewer panicles) than susceptible plants under no-intraspecific competition. Instead, with the increasing competition level, the difference in panicle production at harvest time decreased until it became negligible at 20 plants m -2 . Evaluation of total dry biomass as well as biomass allocation in vegetative parts did not highlight any difference between resistant and susceptible plants. Instead, panicle dry weight was higher in susceptible plants indicating that they allocated more biomass than resistant ones to the reproductive organs, especially in no-competition and in competition situations at lower plant densities. The different fitness between resistant and susceptible phenotypes suggests that keeping the infestation density as low as possible can increase the reproduction success of the susceptible phenotype and therefore contribute to lowering the ratio between resistant and susceptible alleles. If adequately embedded in a

VEGETATIVE SUPPORT OF CARDIAC ACTIVITY IN ATHLETES WITH DIFFERENT ANTHROPOMETRIC PROFILE

Directory of Open Access Journals (Sweden)

O. N. Kudrya

2016-01-01

Full Text Available The purpose of research – to study the features of the functioning of the cardiovascular system and regulatory mechanisms of the young athletes of different heights.Materials and methods. The study included athletes aged 15-16 (32 girls and 36 boys engaged in competitive sports. To study the autonomic regulation of the cardiovascular system using mathematical methods and spectral analysis of heart rate variability. To characterize the vegetative support the circulatory apparatus, all subjects performed an active orthostatic test.Results. The features of vegetative maintenance of heart activity in tall athletes: stress regulatory mechanisms observed resting in tall men and decrease the functionality of the sympathetic division of the autonomic nervous system during active orthostatic test in athletes of different sex. Athletes tall urgent adaptation of the cardiovascular system to changing external conditions associated with activation of suprasegmental divisions of the autonomic nervous system and the excessive activation of the sympathetic division, which is an inefficient way of adaptation.Conclusion. Thus, high growth is evident not only in the increase of total size of the body of athletes, but also in the peculiarities of morphofunctional state involved, indicating the need of individual rationing of loads for tall players. The revealed morphofunctional characteristics of the organism tall athletes allow us to recommend an increase in the proportion of aerobic exercise to enhance the adaptive capacities of the organism. 

Reducing Competitive Cache Misses in Modern Processor Architectures

OpenAIRE

Prisagjanec, Milcho; Mitrevski, Pece

2017-01-01

The increasing number of threads inside the cores of a multicore processor, and competitive access to the shared cache memory, become the main reasons for an increased number of competitive cache misses and performance decline. Inevitably, the development of modern processor architectures leads to an increased number of cache misses. In this paper, we make an attempt to implement a technique for decreasing the number of competitive cache misses in the first level of cache memory. This tec...

Robotic Range Clearance Competition (R2C2)

Science.gov (United States)

2011-10-01

MON TUE MAP MAP VEG automated vegetation clearance, automated Aug 10 Aug 11 WED THU Med VEG ia and Visitor D MAP ay Aug 12 FRI SURF...competitors will not be penalized if they enter this area. For the competition we will add an additional Pan , Tilt, Zoom (PTZ) Camera that will be...Johnston’s Corner –Gas Station Restaurant: Pizza, Fired Chicken , Subs 550 W Whalen St., Guernsey, WY 82214 (307) 836-3155 R2C2 Competitor Information

Silicon Decreases Dimethylarsinic Acid Concentration in Rice Grain and Mitigates Straighthead Disorder.

Science.gov (United States)

Limmer, Matthew Alan; Wise, Patrick; Dykes, Gretchen E; Seyfferth, Angelia L

2018-04-17

While root Si transporters play a role in the uptake of arsenite and organic As species dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) in rice ( Oryza sativa L.), the impact of Si addition on the accumulation of DMA and MMA in reproductive tissues has not been directly evaluated, particularly in isolation from inorganic As species. Furthermore, DMA and MMA are suspected causal agents of straighthead disorder. We performed a hydroponic study to disentangle the impact of Si on accumulation of DMA and MMA in rice grain. At 5 μM, MMA was toxic to rice, regardless of Si addition, although Si significantly decreased root MMA concentrations. Plants dosed with 5 μM DMA grew well vegetatively but exhibited straighthead disorder at the lowest Si dose, and this DMA-induced yield loss reversed with increasing solution Si. Increasing Si also significantly decreased DMA concentrations in roots, straw, husk, and grain, particularly in mature plants. Si restricted grain DMA through competition for root uptake and downregulation of root Si transporters particularly at later stages of growth when Si uptake was greatest. Our finding that DMA causes straighthead disorder under low Si availability but not under high Si availability suggests Si as a straighthead management strategy.

COMPETITION AS MARKET MECHANISM

Directory of Open Access Journals (Sweden)

N. Ya. Kazhuro

2015-01-01

Full Text Available The essence of a competition as an objective law for development of the commodities production based on private ownership of the means of production and commodity exchange has been revealed in the paper. The paper presents an economic basis of market economy (private ownership which generates a corresponding production objective. Such purpose is a maximization of profit and a minimization of market subject expenses. Therefore, a struggle for the most favourable conditions on commodity production and sales is inevitable in such situation. The struggle is considered in the community with developed market economy as a competition.The competition is regarded not as an exogenic factor exerting its influence on market economic system from the outside, but as an objective phenomenon which is inherent to management market system in itself. Such treatment is substantiated by economic disintegration of individual commodity producers. Being an important engine of market economy, the competition does not establish its laws, and its role is to be an executive of data which are internally inherent in commodity production laws and firstly it concerns a profit maximization law which defines a purpose and guiding motif of economic entities in the given economy.The competition plays a contradictory role under conditions of market economy. On the one hand, it makes manufacturers constantly to aspire to expense reduction for the sake of profit increase. This has resulted in labour productivity increase, production cost decrease and a company receives an opportunity to reduce retail price for its products. Consequently, the competition acts as a potential factor for lowering of prices while increasing production efficiency. On the other hand, sellers have more freedom in price fixing under conditions of imperfect competition as they sell their products under the conditions of a monopolistic competition or an oligopoly. This is the main weakest point of the market

Unification of the methodology of competitiveness evaluation

Directory of Open Access Journals (Sweden)

Ivanova Marina

2016-05-01

Full Text Available The purpose of the study is the comparison of the modern methods of competitiveness evaluation and testing the results in practice at a production plant in order to unify the methodology. Analysis of the publications shows that the existing diversity in methods of the competitiveness evaluation complicates the choice of a method and interpretation of the results, which confirms the need to classify and unify the methods available today. The authors suggest that the standardized method of competitiveness evaluation should combine matrix and graphical methods. In our study, we have shown that SWOT-analysis should be carried out in two stages: firstly, it is necessary to determine the strengths and weaknesses of the company, taking into account the following factors: marketing, production, economic and financial situation, technology, the administration and personnel; secondly, it is essential to assess the opportunities and threats with the allowance for the political, legal, and economic situation, the impact of market as well as social, cultural and natural environmental factors. The proposed methodology of competitiveness evaluation has been tested at the industrial enterprise "Olvita ltd", which is dynamically developing and successfully operates on the food market of Ukraine; it specializes in processing, logistics and distribution of fresh and frozen vegetables, fruits and berries, as well as ready-to cook meat products. The results have shown that the competitiveness evaluation remains a pressing issue that requires simple and fairly demonstrative methods, one of which is a method that combines both graphical and matrix approaches. The advantage of the proposed method is its sufficiently high visualizations and record of personal approaches in evaluating the scores for strengths and weaknesses as well as opportunities and threats. In the future, the authors are planning to examine and systemize the indicators used in the competitiveness

Vegetative Propagule Pressure and Water Depth Affect Biomass and Evenness of Submerged Macrophyte Communities.

Science.gov (United States)

Li, Hong-Li; Wang, Yong-Yang; Zhang, Qian; Wang, Pu; Zhang, Ming-Xiang; Yu, Fei-Hai

2015-01-01

Vegetative propagule pressure may affect the establishment and structure of aquatic plant communities that are commonly dominated by plants capable of clonal growth. We experimentally constructed aquatic communities consisting of four submerged macrophytes (Hydrilla verticillata, Ceratophyllum demersum, Elodea nuttallii and Myriophyllum spicatum) with three levels of vegetative propagule pressure (4, 8 and 16 shoot fragments for communities in each pot) and two levels of water depth (30 cm and 70 cm). Increasing vegetative propagule pressure and decreasing water level significantly increased the growth of the submerged macrophyte communities, suggesting that propagule pressure and water depth should be considered when utilizing vegetative propagules to re-establish submerged macrophyte communities in degraded aquatic ecosystems. However, increasing vegetative propagule pressure and decreasing water level significantly decreased evenness of the submerged macrophyte communities because they markedly increased the dominance of H. verticillata and E. nuttallii, but had little impact on that of C. demersum and M. spicatum. Thus, effects of vegetative propagule pressure and water depth are species-specific and increasing vegetative propagule pressure under lower water level can facilitate the establishment success of submerged macrophyte communities.

Vegetation index anomaly response to varying lengths of drought across vegetation and climatic gradients in Hawaii

Science.gov (United States)

Lucas, M.; Miura, T.; Trauernicht, C.; Frazier, A. G.

2017-12-01

A drought which results in prolonged and extended deficit in naturally available water supply and creates multiple stresses across ecosystems is classified as an ecological drought. Detecting and understanding the dynamics and response of such droughts in tropical systems, specifically across various vegetation and climatic gradients is fairly undetermined, yet increasingly important for better understandings of the ecological effects of drought. To understanding the link between what lengths and intensities of known meteorological drought triggers detectable ecological vegetation responses, a landscape scale regression analysis evaluating the response (slope) and relationship strength (R-squared) of several cumulative SPI (standard precipitation index) lengths(1, 3, 6, 12, 18, 24, 36, 48, and 60 month), to various satellite derived monthly vegetation indices anomalies (NDVI, EVI, EVI2, and LSWI) was performed across a matrix of dominant vegetation covers (grassland, shrubland, and forest) and climatic moisture zones (arid, dry, mesic, and wet). The nine different SPI lags across these climactic and vegetation gradients was suggest that stronger relationships and steeper slopes were found in dryer climates (across all vegetation covers) and finer vegetation types (across all moisture zones). Overall NDVI, EVI and EVI2 showed the best utility in these dryer climatic zones across all vegetation types. Within arid and dry areas "best" fits showed increasing lengths of cumulative SPI were with increasing vegetation coarseness respectively. Overall these findings suggest that rainfall driven drought may have a stronger impact on the ecological condition of vegetation in water limited systems with finer vegetation types ecologically responding more rapidly to meteorological drought events than coarser woody vegetation systems. These results suggest that previously and newly documented trends of decreasing rainfall and increasing drought in Hawaiian drylands may have

Drought-induced vegetation stress in southwestern North America

International Nuclear Information System (INIS)

Zhang Xiaoyang; Goldberg, Mitchell; Tarpley, Dan; Kogan, Felix; Yu Yunyue; Friedl, Mark A; Morisette, Jeffrey

2010-01-01

Trends towards earlier greenup and increased average greenness have been widely reported in both humid and dry ecosystems. By analyzing NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) data from 1982 to 2007, we report complex trends in both the growing season amplitude and seasonally integrated vegetation greenness in southwestern North America and further highlight regions consistently experiencing drought stress. In particular, greenness measurements from 1982 to 2007 show an increasing trend in grasslands but a decreasing trend in shrublands. However, vegetation greenness in this period has experienced a strong cycle, increasing from 1982 to 1993 but decreasing from 1993 to 2007. The significant decrease during the last decade has reduced vegetation greenness by 6% in shrublands and 13% in grasslands (16% and 21%, respectively, in the severe drought years). The greenness cycle correlates to both annual precipitation and dry season length derived from NOAA North America Regional Reanalysis data. If drought events continue as predicted by climate models, they will exacerbate ecosystem degradation and reduce carbon uptake.

A competitive edge in France around EDF?

International Nuclear Information System (INIS)

Glachant, J.M.; Saguan, M.

2006-01-01

The French electric reform displays a rather particular case of creation of a competitive market around a former very large integrated monopoly that retains all of its industrial assets. This new market is growing like a competitive edge around the former monopoly The prevailing operator, which has mainly nuclear and hydraulic production equipment, could withstand all pressures from competitors during the initial price decrease phase, without openly abusing its market power. As a result, apart from the hypothesis of gigantic public offerings, the French market trend towards an ordinary competitive system does not seem likely to happen soon or spontaneously. (authors)

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

International Nuclear Information System (INIS)

Geurts, Jeroen J.M.; Sarneel, Judith M.; Willers, Bart J.C.; Roelofs, Jan G.M.; Verhoeven, Jos T.A.; Lamers, Leon P.M.

2009-01-01

Both eutrophication and SO 4 pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO 4 were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO 4 addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO 4 pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO 4 pollution, sulphide toxicity and nutrient availability.

Competition for pollinators and intra-communal spectral dissimilarity of flowers

NARCIS (Netherlands)

van der Kooi, C. J.; Pen, I.; Staal, M.; Stavenga, D. G.; Elzenga, J. T. M.

Competition for pollinators occurs when, in a community of flowering plants, several simultaneously flowering plant species depend on the same pollinator. Competition for pollinators increases interspecific pollen transfer rates, thereby reducing the number of viable offspring. In order to decrease

APPROACHING COMPETITIVENESS AT THE LEVEL OF MULTINATIONAL COMPANIES

Directory of Open Access Journals (Sweden)

DORINA NIŢĂ

2011-01-01

Full Text Available The competitiveness of multinational corporations is a particularly complex concept due to the fact that at present this type of company represents economic entities which continue to develop in the context of the process of internationalization and the transition to the use of global strategies. Competitiveness is a competition between corporations for new positions on the markets. With regard to the competitiveness of multinational corporations, the most accurate description was given by Gilbert Abraham Frois who believed these businesses must think globally, but act locally. In the competitive global market, emphasis is laid on plus – the value given by the competitiveness of the human element, taking into account the fact that the human resource doesn’t run out, and its value doesn’t decrease over time, but on the contrary, its value increases on condition that it is rigorously managed and developed.

Vegetative Propagule Pressure and Water Depth Affect Biomass and Evenness of Submerged Macrophyte Communities.

Directory of Open Access Journals (Sweden)

Hong-Li Li

Full Text Available Vegetative propagule pressure may affect the establishment and structure of aquatic plant communities that are commonly dominated by plants capable of clonal growth. We experimentally constructed aquatic communities consisting of four submerged macrophytes (Hydrilla verticillata, Ceratophyllum demersum, Elodea nuttallii and Myriophyllum spicatum with three levels of vegetative propagule pressure (4, 8 and 16 shoot fragments for communities in each pot and two levels of water depth (30 cm and 70 cm. Increasing vegetative propagule pressure and decreasing water level significantly increased the growth of the submerged macrophyte communities, suggesting that propagule pressure and water depth should be considered when utilizing vegetative propagules to re-establish submerged macrophyte communities in degraded aquatic ecosystems. However, increasing vegetative propagule pressure and decreasing water level significantly decreased evenness of the submerged macrophyte communities because they markedly increased the dominance of H. verticillata and E. nuttallii, but had little impact on that of C. demersum and M. spicatum. Thus, effects of vegetative propagule pressure and water depth are species-specific and increasing vegetative propagule pressure under lower water level can facilitate the establishment success of submerged macrophyte communities.

Spatial heterogeneity in light supply affects intraspecific competition of a stoloniferous clonal plant.

Directory of Open Access Journals (Sweden)

Pu Wang

Full Text Available Spatial heterogeneity in light supply is common in nature. Many studies have examined the effects of heterogeneous light supply on growth, morphology, physiology and biomass allocation of clonal plants, but few have tested those effects on intraspecific competition. In a greenhouse experiment, we grew one (no competition or nine ramets (with intraspecific competition of a stoloniferous clonal plant, Duchesnea indica, in three homogeneous light conditions (high, medium and low light intensity and two heterogeneous ones differing in patch size (large and small patch treatments. The total light in the two heterogeneous treatments was the same as that in the homogeneous medium light treatment. Both decreasing light intensity and intraspecific competition significantly decreased the growth (biomass, number of ramets and total stolon length of D. indica. As compared with the homogeneous medium light treatment, the large patch treatment significantly increased the growth of D. indica without intraspecific competition. However, the growth of D. indica with competition did not differ among the homogeneous medium light, the large and the small patch treatments. Consequently, light heterogeneity significantly increased intraspecific competition intensity, as measured by the decreased log response ratio. These results suggest that spatial heterogeneity in light supply can alter intraspecific interactions of clonal plants.

Competition and product quality in the supermarket industry.

Science.gov (United States)

Matsa, David A

2011-01-01

This article analyzes the effect of competition on a supermarket firm's incentive to provide product quality. In the supermarket industry, product availability is an important measure of quality. Using U.S. Consumer Price Index microdata to track inventory shortfalls, I find that stores facing more intense competition have fewer shortfalls. Competition from Walmart—the most significant shock to industry market structure in half a century—decreased shortfalls among large chains by about a third. The risk that customers will switch stores appears to provide competitors with a strong incentive to invest in product quality.

Chemical Composition and Quality Characteristics of Wheat Bread Supplemented with Leafy Vegetable Powders

Directory of Open Access Journals (Sweden)

T. V. Odunlade

2017-01-01

Full Text Available The study investigated the effect of supplementation of the leaf powders of Telfairia occidentalis, Amaranthus viridis, and Solanum macrocarpon on the chemical composition and the quality characteristics of wheat bread. The bread samples were supplemented with each of the vegetable leaf powders at 1%, 2%, and 3% during preparation. The bread samples were assayed for proximate composition, mineral composition, physical, sensory, and antioxidant properties using standard methods. The addition of vegetable powders significantly increased the protein (9.50 to 13.93%, fibre (1.81 to 4.00%, ash (1.05 to 2.38%, and fat (1.27 to 2.00%. Supplementation with vegetable powder however significantly decreased (p<0.05 the carbohydrate and moisture contents. Significant (p<0.05 increases were recorded for all evaluated minerals as the level of vegetable powder increased. Supplementation with vegetable powder caused significant decrease in total phenolic content, percentage DPPH inhibition, metal chelating ability, ferric reducing antioxidant power, and total antioxidant capacity. Sensory results showed that there was significant decrease in sensory qualities with increasing supplementation. This therefore suggests that bread supplemented with vegetable powder could have more market penetration if awareness is highly created.

A critical review on effects, tolerance mechanisms and management of cadmium in vegetables.

Science.gov (United States)

Rizwan, Muhammad; Ali, Shafaqat; Adrees, Muhammad; Ibrahim, Muhammad; Tsang, Daniel C W; Zia-Ur-Rehman, Muhammad; Zahir, Zahir Ahmad; Rinklebe, Jörg; Tack, Filip M G; Ok, Yong Sik

2017-09-01

Cadmium (Cd) accumulation in vegetables is an important environmental issue that threatens human health globally. Understanding the response of vegetables to Cd stress and applying management strategies may help to reduce the Cd uptake by vegetables. The aim of the present review is to summarize the knowledge concerning the uptake and toxic effects of Cd in vegetables and the different management strategies to combat Cd stress in vegetables. Leafy vegetables grown in Cd contaminated soils potentially accumulate higher concentrations of Cd, posing a threat to food commodities. The Cd toxicity decreases seed germination, growth, biomass and quality of vegetables. This reduces the photosynthesis, stomatal conductance and alteration in mineral nutrition. Toxicity of Cd toxicity also interferes with vegetable biochemistry causing oxidative stress and resulting in decreased antioxidant enzyme activities. Several management options have been employed for the reduction of Cd uptake and toxicity in vegetables. The exogenous application of plant growth regulators, proper mineral nutrition, and the use of organic and inorganic amendments might be useful for reducing Cd toxicity in vegetables. The use of low Cd accumulating vegetable cultivars in conjunction with insolubilizing amendments and proper agricultural practices might be a useful technique for reducing Cd exposure in the food chain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exhibitionist Eating: Who Wins Eating Competitions?

Science.gov (United States)

Wansink, Brian; Kniffin, Kevin M

2016-01-01

How and why does competition and spectator involvement influence eating behaviors? The primary objective of this article is to explore the nature of competitive eating with the goal of identifying implications for other social situations. Study 1 investigated how many chicken wings were eaten by men and women in a 30-min eating competition when cheering spectators either were or were not present (compared to a control condition). The second study sought to explain Study 1's findings through a survey of 93 students who rated male or female competitive eaters (in randomized order) based on intelligence, attractiveness, health, strength, and how romantic they expected the eaters to be. Exploratory findings show competitive eaters ate approximately four times as many chicken wings as a similar control group, and the presence of a cheering audience further increased wing consumption for males (but decreased consumption for females). Study 2 suggests part of the over-performance of males may be related to a shared positive perception that competitive male eaters are strong and virile. Even in relatively low-stakes environments, competitive visibility may dramatically increase how much males eat. These preliminary results help illuminate recent discoveries that males overeat in various social situations where there are opportunities for men to "show off." This may have relevance for dining behavior - especially among younger males - at parties, banquets, group dinners, and similar social situations.

A hybrid of monopoly and perfect competition model for hi-tech products

Science.gov (United States)

Yang, P. C.; Wee, H. M.; Pai, S.; Yang, H. J.; Wee, P. K. P.

2010-11-01

For Hi-tech products, the demand rate, the component cost as well as the selling price usually decline significantly with time. In the case of perfect competition, shortages usually result in lost sales; while in a monopoly, shortages will be completely backordered. However, neither perfect competition nor monopoly exists. Therefore, there is a need to develop a replenishment model considering a hybrid of perfect competition and monopoly when the cost, price and demand are decreasing simultaneously. A numerical example and sensitivity analysis are carried out to illustrate this model. The results show that a higher decline-rate in the component cost leads to a smaller service level and a larger replenishment interval. When the component cost decline rate increases and the selling price decline rate decreases simultaneously, the replenishment interval decreases. In perfect competition it is better to have a high service level, while for the case with monopoly, keeping a low service level is better due to complete backordering.

Wildfires alter rodent community structure across four vegetation types in southern California, USA

Science.gov (United States)

Brehme, Cheryl S.; Clark, Denise R.; Rochester, Carlton J.; Fisher, Robert N.

2011-01-01

We surveyed burned and unburned plots across four habitat reserves in San Diego County, California, USA, in 2005 and 2006, to assess the effects of the 2003 wildfires on the community structure and relative abundance of rodent species. The reserves each contained multiple vegetation types (coastal sage scrub, chaparral, woodland, and grassland) and spanned from 250 m to 1078 m in elevation. Multivariate analyses revealed a more simplified rodent community structure in all burned habitats in comparison to unburned habitats. Reduction in shrub and tree cover was highly predictive of changes in post-fire rodent community structure in the burned coastal sage scrub and chaparral habitats. Reduction in cover was not predictive for the less substantially burned woodlands and grasslands, for which we hypothesized that interspecific competition played a greater role in post-fire community structure. Across vegetation types, generalists and open habitat specialists typically increased in relative abundance, whereas closed habitat specialists decreased. We documented significant increases in relative abundance of the deer mouse (Peromyscus maniculatus Wagner) and Dulzura kangaroo rat (Dipodomys simulans Merriam). In contrast, we found significant decreases in relative abundance for the California mouse (Peromyscus californicus Gambel), San Diego pocket mouse (Chaetodipus fallax Merriam), desert woodrat (Neotoma lepida Thomas), and brush mouse (Peromyscus boylii Baird). Currently, our research program involves assessment of whether habitat conservation plans (HCPs) in southern California provide long-term protection to HCP covered species, as well as preserve ecosystem function. The scenario of increased wildfires needs to be incorporated into this assessment. We discuss our results in relation to management and conservation planning under a future scenario of larger and more frequent wildfires in southern California.

Demolishing the competition: the longitudinal link between competitive video games, competitive gambling, and aggression.

Science.gov (United States)

Adachi, Paul J C; Willoughby, Teena

2013-07-01

The majority of research on the link between video games and aggression has focused on the violent content in games. In contrast, recent experimental research suggests that it is video game competition, not violence, that has the greatest effect on aggression in the short-term. However, no researchers have examined the long-term relationship between video game competition and aggression. In addition, if competition in video games is a significant reason for the link between video game play and aggression, then other competitive activities, such as competitive gambling, also may predict aggression over time. In the current study, we directly assessed the socialization (competitive video game play and competitive gambling predicts aggression over time) versus selection hypotheses (aggression predicts competitive video game play and competitive gambling over time). Adolescents (N = 1,492, 50.8 % female) were surveyed annually from Grade 9 to Grade 12 about their video game play, gambling, and aggressive behaviors. Greater competitive video game play and competitive gambling predicted higher levels of aggression over time, after controlling for previous levels of aggression, supporting the socialization hypothesis. The selection hypothesis also was supported, as aggression predicted greater competitive video game play and competitive gambling over time, after controlling for previous competitive video game play and competitive gambling. Our findings, taken together with the fact that millions of adolescents play competitive video games every day and that competitive gambling may increase as adolescents transition into adulthood, highlight the need for a greater understanding of the relationship between competition and aggression.

Herbivory more limiting than competition on early and established native plants in an invaded meadow.

Science.gov (United States)

Gonzales, Emily K; Arcese, Peter

2008-12-01

The dominance of nonnative plants coupled with declines of native plants suggests that competitive displacement drives extinctions, yet empirical examples are rare. Herbivores, however, can alter vegetation structure and reduce diversity when abundant. Herbivores may act on mature, reproductive life stages whereas some of the strongest competitive effects might occur at early life stages that are difficult to observe. For example, competition by perennial nonnative grasses can interfere with the establishment of native seeds. We contrasted the effects of ungulate herbivory and competition by neighboring plants on the performance of native plant species at early and established life stages in invaded oak meadows. We recorded growth, survival, and flowering in two native species transplanted as established plants, six native species grown from seed, and five extant lily species as part of two 2 x 2 factorial experiments that manipulated herbivory and competition. Herbivory reduced the performance of nearly all focal native species at early and established life stages, whereas competition had few measurable effects. Our results suggest that herbivory has a greater local influence on native plant species than competition and that reducing herbivore impacts will be required to successfully restore endangered oak meadows where ungulates are now abundant.

Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

Science.gov (United States)

Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

2016-07-15

The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of vegetation on rock and soil type discrimination

Science.gov (United States)

Siegal, B. S.; Goetz, A. F. H.

1977-01-01

The effect of naturally occurring vegetation on the spectral reflectance of earth materials in the wavelength region of 0.45 to 2.4 microns is determined by computer averaging of in situ acquired spectral data. The amount and type of vegetation and the spectral reflectance of the ground are considered. Low albedo materials may be altered beyond recognition with only ten per cent green vegetation cover. Dead or dry vegetation does not greatly alter the shape of the spectral reflectance curve and only changes the albedo with minimum wavelength dependency. With increasing amounts of vegetation the Landsat MSS band ratios 4/6, 4/7, 5/6, and 5/7 are significantly decreased whereas MSS ratios 4/5 and 6/7 remain entirely constant.

Impacts of Vegetation Growth on Reach-scale Flood Hydraulics in a Sand-bed River and the Implications for Vegetation-morphology Coevolution

Science.gov (United States)

Box, S.; Wilcox, A. C.

2017-12-01

Vegetation alters flood hydraulics and geomorphic response, yet quantifying and predicting such responses across spatial and temporal scales remains challenging. Plant- and patch-scale studies consistently show that vegetation increases local hydraulic variability, yet reach-scale hydrodynamic models often assume vegetation has a spatially homogeneous effect on hydraulics. Using Nays2DH in iRIC (International River Interface Cooperative), we model the effect of spatially heterogeneous vegetation on a series of floods with varying antecedent vegetation conditions in a sand-bed river in western Arizona, taking advantage of over a decade of data on a system that experienced substantial geomorphic, hydrologic, and ecosystem changes. We show that pioneer woody seedlings (Tamarix, Populus, Salix) and cattail (Typha) increase local hydraulic variability, including velocity and bed shear stress, along individual cross sections, predominantly by decreasing velocity in zones of vegetation establishment and growth and increasing velocity in unvegetated areas, with analogous effects on shear stress. This was especially prominent in a study reach where vegetation growth contributed to thalweg incision relative to a vegetated bar. Evaluation of these results in the context of observed geomorphic response to floods elucidates mechanisms by which vegetation and channel morphology coevolve at a reach scale. By quantifying the influence of spatially heterogeneous vegetation on reach-scale hydraulics, we demonstrate that plant- and patch-scale research on vegetation hydraulics is applicable to ecogeomorphology at the reach scale.

Trade Openness, Market Competition, and Inflation: Some Sectoral Evidence from OECD Countries

OpenAIRE

Mahir Binici; Yin-Wong Cheung; Kon S. Lai

2011-01-01

This study evaluates the role market competition plays in determining inflation based on sector-level data from OECD countries. In theory, trade openness can affect inflation through changes in market competitiveness and productivity. Nonetheless, previous empirical studies often fail to account for productivity effects, and their results may overstate the role of market competition. This study shows that inflation decreases with greater market competitiveness even after controlling for produ...

Terrestrial Feedbacks Incorporated in Global Vegetation Models through Observed Trait-Environment Responses

Science.gov (United States)

Bodegom, P. V.

2015-12-01

Most global vegetation models used to evaluate climate change impacts rely on plant functional types to describe vegetation responses to environmental stresses. In a traditional set-up in which vegetation characteristics are considered constant within a vegetation type, the possibility to implement and infer feedback mechanisms are limited as feedback mechanisms will likely involve a changing expression of community trait values. Based on community assembly concepts, we implemented functional trait-environment relationships into a global dynamic vegetation model to quantitatively assess this feature. For the current climate, a different global vegetation distribution was calculated with and without the inclusion of trait variation, emphasizing the importance of feedbacks -in interaction with competitive processes- for the prevailing global patterns. These trait-environmental responses do, however, not necessarily imply adaptive responses of vegetation to changing conditions and may locally lead to a faster turnover in vegetation upon climate change. Indeed, when running climate projections, simulations with trait variation did not yield a more stable or resilient vegetation than those without. Through the different feedback expressions, global and regional carbon and water fluxes were -however- strongly altered. At a global scale, model projections suggest an increased productivity and hence an increased carbon sink in the next decades to come, when including trait variation. However, by the end of the century, a reduced carbon sink is projected. This effect is due to a downregulation of photosynthesis rates, particularly in the tropical regions, even when accounting for CO2-fertilization effects. Altogether, the various global model simulations suggest the critical importance of including vegetation functional responses to changing environmental conditions to grasp terrestrial feedback mechanisms at global scales in the light of climate change.

Tax competition and tax harmonization in the European Union

Directory of Open Access Journals (Sweden)

Danuše Nerudová

2004-01-01

Full Text Available The article deals with the problems of tax competition and harmonization within the European Union. It reveals the single difficulties connected with harmonization, identifies the problems arising from tax competition and points out the harmful tax competition as well. Single compulsory harmonized tax base in connection with prevailing tax competition in the area of tax rates is the suggested solution in the scope of direct taxation. As the solution in the area of indirect taxation could serve the introduction of “principle of origin”. This would cause remarkable administrative costs decrease not only for economic subjects but for tax authorities as well.

IMPACT OF TRIBE TRITICEAE VARIETIES ON STRUCTURE AND COMPETITIVENESS OF SEGETAL GROUP

Directory of Open Access Journals (Sweden)

T. Z. Moskalets

2016-03-01

Full Text Available We studied the influence of varieties of tribe Triticeae (Soft Wheat, Winter Rye and Winter Triticale on the structure and competitiveness of segetal vegetation. It is shown that in the conditions of Polissya, Forest-Steppe Polissya, and Forest-Steppe ecotopes the coenotic composition of plant communities was represented mostly by annual plants and at some extent by hemycryptophytes, cryptophytes, and geophytes. The dominant weed associations of Polissya are: Erodium-Neslia; Chenopodiu-Sonchus; Galium-Setaria; Elytrigia-Convolvulus; Apera-Polygonum and Apera-Convolvulus; Polissia-steppe: Viola-Capsella; Matricaria-Galium; Elytrigia-Galeopsis; Chenopodiu-Sonchus; Thlaspi-Euphorbia; Forest-Steppe: Elytrigia-Viola; Matricaria-Taraxacum; Consolida-Convolvulus; Cirsium-Taraxacum; Galium-Stellaria; Thlaspi-Plantago, Linaria-Conyza. In terms of the Central Forest-Steppe and Eastern Polisya the medium-grown and medium ripe Wheat (Yuvivata 60 and Poliska 90, Rye (Borotba, Triticale (Slavetne, Slavetne Polipshene. and AD 256 is the most competitive towards segetal vegetation than other medium-grown and semi-dwarf varieties of such cultures. The introduction of Triticale and Rye in the structure of sown areas are an effective biological control towards segetal vegetation, particularly perennial weeds. We revealed that increasing doses of fertilizers on crops of the tribe Triticeae stimulates the growth of weeds, but the specific weight per unit area does not always correlate with density concerning cultural species. We registered the dominant competitive weeds associations in winter crops, regardless of grade, but their differentiation by population strategy and specific weight per unit area depends on the type and conditions of the specific ecotypes. We selected some six associations for the Polissya: Erodium-Neslia; Chenopodiu-Sonchus; Galium-Setaria; Elytrigia-Convolvulus; Apera-Polygonum and Apera-Convolvulus; five for Polissya Steppe

Ultrasonic characterization of vegetable oil product

International Nuclear Information System (INIS)

Sidek Hj Abd Aziz; Chow Sai Pew; Abdul Halim Shaari; Nor Azizah Shaari

1992-01-01

The ultrasonic wave velocity and attenuation of a number vegetable oil products were measured using an ultrasonic pulse echo overlap technique from room temperature up to 90 0 C. Among the liquid samples studied were refined bleach deodorized (RED) palm oil, palm olein, coconut oil, corn oil and soya bean oil. The velocity of sound in vegetable oil products varies from about 1200 to 200 ms-1 and decrease linearly as the temperature increases. The ultrasonic properties of the oil are much dependent on their viscosity, density, relaxation effect and vibrational anharmonicity

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland.

Science.gov (United States)

Galas, Aleksander; Cebulska-Wasilewska, Antonina

2015-03-01

Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and cooked vegetables and fruits on SCE frequency. A total of 62 participants included colorectal cancer (CRC) patients, hospital-based controls and healthy laboratory workers. SCE frequency was assessed in blood lymphocytes. Frequency of vegetable and fruit consumption was gathered by structured semi-quantitative food frequency questionnaire. SCE frequency was lowest among hospital-based controls (4.4 ± 1.1), a bit higher in CRC patients (4.5 ± 1.0) and highest among laboratory workers (7.4 ± 1.2) (p consumption, but not so for intake of cooked vegetables and fruits. The results of the study have shown the beneficial effect of consumption of raw vegetables on disrupted replication of DNA measured by SCE frequency, implying protection against genotoxic agents. Further effort is required to verify the role of cooked vegetables and fruits.

Novelties in Competition Regulation in Romania. Impact on Competitors

Directory of Open Access Journals (Sweden)

Cornelia LEFTER

2011-10-01

Full Text Available Upon the coming into force of the Law No. 149/2011, the recent changes in the Competition Law bring a significant decrease of the fines level, while encouraging competitors to support the maintenance of a healthy and transparent competition. However, some provisions require application guidelines, while others are tougher than the European law principles.

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

Energy Technology Data Exchange (ETDEWEB)

Geurts, Jeroen J.M., E-mail: j.geurts@b-ware.e [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); B-WARE Research Centre, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Sarneel, Judith M. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Willers, Bart J.C.; Roelofs, Jan G.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Verhoeven, Jos T.A. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Lamers, Leon P.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-07-15

Both eutrophication and SO{sub 4} pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO{sub 4} were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO{sub 4} addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO{sub 4} pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO{sub 4} pollution, sulphide toxicity and nutrient availability.

Exhibitionist eating: Who wins eating competitions?

Directory of Open Access Journals (Sweden)

Brian Wansink

2016-11-01

Full Text Available Objective: How and why does competition and spectator involvement influence eating behaviors? The primary objective of this article is to explore the nature of eating competitions with the goal of identifying implications for other social situations.Design: Study 1 investigated how many chicken wings were eaten by men and women in a 30-minute eating competition when cheering spectators either were or were not present (compared to a control condition. A second study sought to explain Study 1’s findings through a survey of 93 students who rated male or female competitive eaters (in randomized order based on intelligence, attractiveness, health, strength, and how romantic they expected the eaters to be.Results: Exploratory findings show competitive eaters ate approximately four times as many chicken wings as a similar control group, and the presence of a cheering audience further increased wing consumption for males (but decreased consumption for females. Study 2 suggests part of the over-performance of males may be related to a shared positive perception that competitive male eaters are strong and virile. Conclusions: Even in relatively low-stakes environments, competitive visibility may dramatically increase how much males eat. These preliminary results help illuminate recent discoveries that males overeat in various social situations where there are opportunities for men to show off. This may have relevance for dining behavior – especially among younger males – at parties, banquets, group dinners, and similar social situations.

Elevation Control on Vegetation Organization in a Semiarid Ecosystem in Central New Mexico

Science.gov (United States)

Nudurupati, S. S.; Istanbulluoglu, E.; Adams, J. M.; Hobley, D. E. J.; Gasparini, N. M.; Tucker, G. E.; Hutton, E. W. H.

2015-12-01

Many semiarid and desert ecosystems are characterized by patchy and dynamic vegetation. Topography plays a commanding role on vegetation patterns. It is observed that plant biomes and biodiversity vary systematically with slope and aspect, from shrublands in low desert elevations, to mixed grass/shrublands in mid elevations, and forests at high elevations. In this study, we investigate the role of elevation dependent climatology on vegetation organization in a semiarid New Mexico catchment where elevation and hillslope aspect play a defining role on plant types. An ecohydrologic cellular automaton model developed within Landlab (component based modeling framework) is used. The model couples local vegetation dynamics (that simulate biomass production based on local soil moisture and potential evapotranspiration) and plant establishment and mortality based on competition for resources and space. This model is driven by elevation dependent rainfall pulses and solar radiation. The domain is initialized with randomly assigned plant types and the model parameters that couple plant response with soil moisture are systematically changed. Climate perturbation experiments are conducted to examine spatial vegetation organization and associated timescales. Model results reproduce elevation and aspect controls on observed vegetation patterns indicating that this model captures necessary and sufficient conditions that explain these observed ecohydrological patterns.

The use of a commercial vegetable juice as a practical means to increase vegetable intake: a randomized controlled trial.

Science.gov (United States)

Shenoy, Sonia F; Kazaks, Alexandra G; Holt, Roberta R; Chen, Hsin Ju; Winters, Barbara L; Khoo, Chor San; Poston, Walker S C; Haddock, C Keith; Reeves, Rebecca S; Foreyt, John P; Gershwin, M Eric; Keen, Carl L

2010-09-17

Recommendations for daily dietary vegetable intake were increased in the 2005 USDA Dietary Guidelines as consumption of a diet rich in vegetables has been associated with lower risk of certain chronic health disorders including cardiovascular disease. However, vegetable consumption in the United States has declined over the past decade; consequently, the gap between dietary recommendations and vegetable intake is widening. The primary aim of this study is to determine if drinking vegetable juice is a practical way to help meet daily dietary recommendations for vegetable intake consistent with the 2005 Dietary Guidelines and the Dietary Approaches to Stop Hypertension (DASH) diet. The secondary aim is to assess the effect of a vegetable juice on measures of cardiovascular health. We conducted a 12-week, randomized, controlled, parallel-arm study consisting of 3 groups of free-living, healthy volunteers who participated in study visits at the Ragle Human Nutrition Research Center at the University of California, Davis. All subjects received education on the DASH diet and 0, 8 or 16 fluid ounces of vegetable juice daily. Assessments were completed of daily vegetable servings before and after incorporation of vegetable juice and cardiovascular health parameters including blood pressure. Without the juice, vegetable intake in all groups was lower than the 2005 Dietary Guidelines and DASH diet recommendations. The consumption of the vegetable juice helped participants reach recommended intake. In general, parameters associated with cardiovascular health did not change over time. However, in the vegetable juice intervention groups, subjects who were pre-hypertensive at the start of the study showed a significant decrease in blood pressure during the 12-week intervention period. Including 1-2 cups of vegetable juice daily was an effective and acceptable way for healthy adults to close the dietary vegetable gap. Increase in daily vegetable intake was associated with a

The use of a commercial vegetable juice as a practical means to increase vegetable intake: a randomized controlled trial

Directory of Open Access Journals (Sweden)

Reeves Rebecca S

2010-09-01

Full Text Available Abstract Background Recommendations for daily dietary vegetable intake were increased in the 2005 USDA Dietary Guidelines as consumption of a diet rich in vegetables has been associated with lower risk of certain chronic health disorders including cardiovascular disease. However, vegetable consumption in the United States has declined over the past decade; consequently, the gap between dietary recommendations and vegetable intake is widening. The primary aim of this study is to determine if drinking vegetable juice is a practical way to help meet daily dietary recommendations for vegetable intake consistent with the 2005 Dietary Guidelines and the Dietary Approaches to Stop Hypertension (DASH diet. The secondary aim is to assess the effect of a vegetable juice on measures of cardiovascular health. Methods We conducted a 12-week, randomized, controlled, parallel-arm study consisting of 3 groups of free-living, healthy volunteers who participated in study visits at the Ragle Human Nutrition Research Center at the University of California, Davis. All subjects received education on the DASH diet and 0, 8 or 16 fluid ounces of vegetable juice daily. Assessments were completed of daily vegetable servings before and after incorporation of vegetable juice and cardiovascular health parameters including blood pressure. Results Without the juice, vegetable intake in all groups was lower than the 2005 Dietary Guidelines and DASH diet recommendations. The consumption of the vegetable juice helped participants reach recommended intake. In general, parameters associated with cardiovascular health did not change over time. However, in the vegetable juice intervention groups, subjects who were pre-hypertensive at the start of the study showed a significant decrease in blood pressure during the 12-week intervention period. Conclusion Including 1-2 cups of vegetable juice daily was an effective and acceptable way for healthy adults to close the dietary vegetable

Detecting Historical Vegetation Changes in the Dunhuang Oasis Protected Area Using Landsat Images

Directory of Open Access Journals (Sweden)

Xiuxia Zhang

2017-09-01

Full Text Available Abstract: Given its proximity to an artificial oasis, the Donghu Nature Reserve in the Dunhuang Oasis has faced environmental pressure and vegetation disturbances in recent decades. Satellite vegetation indices (VIs can be used to detect such changes in vegetation if the satellite images are calibrated to surface reflectance (SR values. The aim of this study was to select a suitable VI based on the Landsat Climate Data Record (CDR products and the absolute radiation-corrected results of Landsat L1T images to detect the spatio-temporal changes in vegetation for the Donghu Reserve during 1986–2015. The results showed that the VI difference (ΔVI images effectively reduced the changes in the source images. Compared with the other VIs, the soil-adjusted vegetation index (SAVI displayed greater robustness to atmospheric effects in the two types of SR images and was more responsive to vegetation changes caused by human factors. From 1986 to 2015, the positive changes in vegetation dominated the overall change trend, with changes in vegetation in the reserve decreasing during 1990–1995, increasing until 2005–2010, and then decreasing again. The vegetation changes were mainly distributed at the edge of the artificial oasis outside the reserve. The detected changes in vegetation in the reserve highlight the increased human pressure on the reserve.

Predictive modelling of vegetable firmness after thermal pre-treatments and steaming

NARCIS (Netherlands)

Dekker, M.; Dekkers, E.; Jasper, A.; Baár, C.; Verkerk, R.

2014-01-01

Texture is an important product property that strongly affects the quality evaluation of processed vegetables by consumers. The rate of texture decrease is dependent on the processing temperature and the type of vegetable. A large data set on instrumental texture measurements of carrot and broccoli

[Effects of biochar and nitrification inhibitor incorporation on global warming potential of a vegetable field in Nanjing, China].

Science.gov (United States)

Li, Bo; Li, Qiao-Ling; Fan, Chang-Hua; Sun, Li-Ying; Xiong, Zheng-Qin

2014-09-01

The influences of biochar and nitrification inhibitor incorporation on global warming potential (GWP) of a vegetable field were studied using the static chamber and gas chromatography method. Compared with the treatments without biochar addition, the annual GWP of N2O and CH4 and vegetable yield were increased by 8.7%-12.4% and 16.1%-52.5%, respectively, whereas the greenhouse gas intensity (GHGI) were decreased by 5.4%-28.7% following biochar amendment. Nitrification inhibitor significantly reduced the N2O emission while had little influence on CH4 emission, decreased GWP by 17.5%-20.6%, increased vegetable yield by 21.2%-40.1%, and decreased the GHGI significantly. The combined application of biochar and nitrification inhibitor significantly increased both vegetable yield and GWP, but to a greater extent for vegetable yield. Therefore, nitrification inhibitor incorporation could be served as an appropriate practice for increasing vegetable yield and mitigating GHG emissions in vegetable field.

Natural bodybuilding competition preparation and recovery: a 12-month case study.

Science.gov (United States)

Rossow, Lindy M; Fukuda, David H; Fahs, Christopher A; Loenneke, Jeremy P; Stout, Jeffrey R

2013-09-01

Bodybuilding is a sport in which competitors are judged on muscular appearance. This case study tracked a drug-free male bodybuilder (age 26-27 y) for the 6 mo before and after a competition. The aim of this study was to provide the most comprehensive physiological profile of bodybuilding competition preparation and recovery ever compiled. Cardiovascular parameters, body composition, strength, aerobic capacity, critical power, mood state, resting energy expenditure, and hormonal and other blood parameters were evaluated. Heart rate decreased from 53 to 27 beats/min during preparation and increased to 46 beats/min within 1 mo after competition. Brachial blood pressure dropped from 132/69 to 104/56 mmHg during preparation and returned to 116/64 mmHg at 6 mo after competition. Percent body fat declined from 14.8% to 4.5% during preparation and returned to 14.6% during recovery. Strength decreased during preparation and did not fully recover during 6 months of recovery. Testosterone declined from 9.22 to 2.27 ng/mL during preparation and returned back to the baseline level, 9.91 ng/mL, after competition. Total mood disturbance increased from 6 to 43 units during preparation and recovered to 4 units 6 mo after competition. This case study provides a thorough documentation of the physiological changes that occurred during natural bodybuilding competition and recovery.

Microbial transformations of nitrogen, sulfur and iron dictate vegetation composition in wetlands: a review

Directory of Open Access Journals (Sweden)

Leon P.M. Lamers

2012-04-01

Full Text Available The majority of studies on rhizospheric interactions between microbial communities and vegetation focus on pathogens, mycorrhizal symbiosis, and/or carbon transformations. Although the biogeochemical transformations of nitrogen (N, sulfur (S and iron (Fe have profound effects on plants, these effects have received far less attention. Firstly, all three elements are plant nutrients, and microbial activity significantly changes their mobility and availability. Secondly, microbial oxidation with oxygen supplied by radial oxygen loss (ROL from roots in wetlands causes acidification, while reduction using alternative electron acceptors leads to generation of alkalinity, affecting pH in the rhizosphere and hence plant composition. Thirdly, reduced species of all three elements may become phytotoxic. In addition, Fe cycling is tightly linked to that of S and phosphorus (P. As water level fluctuations are very common in wetlands, rapid changes in the availability of oxygen and alternative terminal electron acceptors will result in strong changes in the prevalent microbial redox reactions, with significant effects on plant growth. Depending on geological and hydrological settings, these interacting microbial transformations change the conditions and resource availability for plants, which are strong drivers of vegetation development and composition by changing relative competitive strengths. Conversely, microbial composition is strongly driven by vegetation composition. Therefore, the combination of micro- and macroecological knowledge is essential to understand the biogeochemical and biological key factors driving heterogeneity and total (i.e., micro-macro community composition at different spatial and temporal scales. As N and S inputs have drastically increased due to anthropogenic forcing and Fe inputs have decreased at a global scale, this combined approach has become even more urgent.

Enzymatic transesterification of waste vegetable oil to produce biodiesel.

Science.gov (United States)

Lopresto, C G; Naccarato, S; Albo, L; De Paola, M G; Chakraborty, S; Curcio, S; Calabrò, V

2015-11-01

An experimental study on enzymatic transesterification was performed to produce biodiesel from waste vegetable oils. Lipase from Pseudomonas cepacia was covalently immobilized on a epoxy-acrylic resin support. The immobilized enzyme exhibited high catalytic specific surface and allowed an easy recovery, regeneration and reutilisation of biocatalyst. Waste vegetable oils - such as frying oils, considered not competitive with food applications and wastes to be treated - were used as a source of glycerides. Ethanol was used as a short chain alcohol and was added in three steps with the aim to reduce its inhibitory effect on lipase activity. The effect of biocatalyst/substrate feed mass ratios and the waste oil quality have been investigated in order to estimate the process performances. Biocatalyst recovery and reuse have been also studied with the aim to verify the stability of the biocatalyst for its application in industrial scale. Copyright © 2015 Elsevier Inc. All rights reserved.

Spatial competition dynamics between reef corals under ocean acidification

Science.gov (United States)

Horwitz, Rael; Hoogenboom, Mia O.; Fine, Maoz

2017-01-01

Climate change, including ocean acidification (OA), represents a major threat to coral-reef ecosystems. Although previous experiments have shown that OA can negatively affect the fitness of reef corals, these have not included the long-term effects of competition for space on coral growth rates. Our multispecies year-long study subjected reef-building corals from the Gulf of Aqaba (Red Sea) to competitive interactions under present-day ocean pH (pH 8.1) and predicted end-of-century ocean pH (pH 7.6). Results showed coral growth is significantly impeded by OA under intraspecific competition for five out of six study species. Reduced growth from OA, however, is negligible when growth is already suppressed in the presence of interspecific competition. Using a spatial competition model, our analysis indicates shifts in the competitive hierarchy and a decrease in overall coral cover under lowered pH. Collectively, our case study demonstrates how modified competitive performance under increasing OA will in all likelihood change the composition, structure and functionality of reef coral communities.

Multiscale remote sensing analysis to monitor riparian and upland semiarid vegetation

Science.gov (United States)

Nguyen, Uyen

The health of natural vegetation communities is of concern due to observed changes in the climatic-hydrological regime and land cover changes particularly in arid and semiarid regions. Monitoring vegetation at multi temporal and spatial scales can be the most informative approach for detecting change and inferring causal agents of change and remediation strategies. Riparian communities are tightly linked to annual stream hydrology, ground water elevations and sediment transport. These processes are subject to varying magnitudes of disturbance overtime and are candidates for multi-scale monitoring. My first research objective focused on the response of vegetation in the Upper San Pedro River, Arizona, to reduced base flows and climate change. I addressed the correlation between riparian vegetation and hydro-climate variables during the last three decades in one of the remaining undammed rivers in the southwestern U.S. Its riparian forest is threatened by the diminishing base flows, attributed by different studies either to increases in evapotranspiration (ET) due to conversion of grasslands to mesquite shrublands in the adjacent uplands, or to increased regional groundwater pumping to serve growing populations in surrounding urban areas and or to some interactions of those causes. Landsat 5 imagery was acquired for pre- monsoon period, when riparian trees had leafed out but before the arrival of summer monsoon rains in July. The result has showed Normalized Difference Vegetation Index (NDVI) values from both Landsat and Moderate Resolution Imaging Spectrometer (MODIS) had significant decreases which positively correlated to river flows, which decreased over the study period, and negatively correlated with air temperatures, which have increased by about 1.4°C from 1904 to the present. The predictions from other studies that decreased river flows could negatively impact the riparian forest were supported by this study. The pre-monsoon Normalized Different Vegetation

Plant functional diversity affects climate-vegetation interaction

Science.gov (United States)

Groner, Vivienne P.; Raddatz, Thomas; Reick, Christian H.; Claussen, Martin

2018-04-01

We present how variations in plant functional diversity affect climate-vegetation interaction towards the end of the African Humid Period (AHP) in coupled land-atmosphere simulations using the Max Planck Institute Earth system model (MPI-ESM). In experiments with AHP boundary conditions, the extent of the green Sahara varies considerably with changes in plant functional diversity. Differences in vegetation cover extent and plant functional type (PFT) composition translate into significantly different land surface parameters, water cycling, and surface energy budgets. These changes have not only regional consequences but considerably alter large-scale atmospheric circulation patterns and the position of the tropical rain belt. Towards the end of the AHP, simulations with the standard PFT set in MPI-ESM depict a gradual decrease of precipitation and vegetation cover over time, while simulations with modified PFT composition show either a sharp decline of both variables or an even slower retreat. Thus, not the quantitative but the qualitative PFT composition determines climate-vegetation interaction and the climate-vegetation system response to external forcing. The sensitivity of simulated system states to changes in PFT composition raises the question how realistically Earth system models can actually represent climate-vegetation interaction, considering the poor representation of plant diversity in the current generation of land surface models.

Competition increases sensitivity of wheat (Triticum aestivum) to biotic plant-soil feedback.

Science.gov (United States)

Hol, W H Gera; de Boer, Wietse; ten Hooven, Freddy; van der Putten, Wim H

2013-01-01

Plant-soil feedback (PSF) and plant competition play an important role in structuring vegetation composition, but their interaction remains unclear. Recent studies suggest that competing plants could dilute pathogenic effects, whereas the standing view is that competition may increase the sensitivity of the focal plant to PSF. In agro-ecosystems each of these two options would yield contrasting outcomes: reduced versus enhanced effects of weeds on crop biomass production. To test the effect of competition on sensitivity to PSF, we grew Triticum aestivum (Common wheat) with and without competition from a weed community composed of Vicia villosa, Chenopodium album and Myosotis arvensis. Plants were grown in sterilized soil, with or without living field inoculum from 4 farms in the UK. In the conditioning phase, field inocula had both positive and negative effects on T. aestivum shoot biomass, depending on farm. In the feedback phase the differences between shoot biomass in T. aestivum monoculture on non-inoculated and inoculated soils had mostly disappeared. However, T. aestivum plants growing in mixtures in the feedback phase were larger on non-inoculated soil than on inoculated soil. Hence, T. aestivum was more sensitive to competition when the field soil biota was present. This was supported by the statistically significant negative correlation between shoot biomass of weeds and T. aestivum, which was absent on sterilized soil. In conclusion, competition in cereal crop-weed systems appears to increase cereal crop sensitivity to soil biota.

EDITORIAL: Physics competitions Physics competitions

Science.gov (United States)

Jordens, H.; Mathelitsch, L.

2009-11-01

1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

Hi-tech products marketing and competitive advantage

Directory of Open Access Journals (Sweden)

Perović Jelena

2004-01-01

Full Text Available The company today, in causes turbulent environment and intensive integrations must cooperate, accept and develop high technology in order to achieve needs of customers. It's only way that companies replay on challenge global environment, decrease costs of investment per capita, decrease the risk, captivate new market and held competitive in causes of global market. High tech technology marketing function is help that results of new technology transfer on economy. Their function is reach need of customers, too. Positive influence of technology is the highest in area of production costs and productivity. Speed years are in front of our and it demands larger productivity, which primary source must be technology changes. High technology marketing is the most provocative framework for take competitive advantage, answer on global change and way of permanent reach rigorous need of customers.

Monitoring of Vegetation Impact Due to Trampling on Cadillac Mountain Summit Using High Spatial Resolution Remote Sensing Data Sets

Science.gov (United States)

Kim, Min-Kook; Daigle, John J.

2012-11-01

Cadillac Mountain—the highest peak along the eastern seaboard of the United States—is a major tourist destination in Acadia National Park, Maine. Managing vegetation impact due to trampling on the Cadillac Mountain summit is extremely challenging because of the large number of visitors and the general open nature of landscape in this fragile subalpine environmental setting. Since 2000, more intensive management strategies—based on placing physical barriers and educational messages for visitors—have been employed to protect threatened vegetation, decrease vegetation impact, and enhance vegetation recovery in the vicinity of the summit loop trail. The primary purpose of this study was to evaluate the effect of the management strategies employed. For this purpose, vegetation cover changes between 2001 and 2007 were detected using multispectral high spatial resolution remote sensing data sets. A normalized difference vegetation index was employed to identify the rates of increase and decrease in the vegetation areas. Three buffering distances (30, 60, and 90 m) from the edges of the trail were used to define multiple spatial extents of the site, and the same spatial extents were employed at a nearby control site that had no visitors. No significant differences were detected between the mean rates of vegetation increase and decrease at the experimental site compared with a nearby control site in the case of a small spatial scale (≤30 m) comparison (in all cases P > 0.05). However, in the medium (≤60 m) and large (≤90 m) spatial scales, the rates of increased vegetation were significantly greater and rates of decreased vegetation significantly lower at the experimental site compared with the control site (in all cases P Management implications are explored in terms of the spatial strategies used to decrease the impact of trampling on vegetation.

Smart phone video game simulation of parent-child interaction: Learning skills for effective vegetable parenting

Science.gov (United States)

Higher levels of vegetable intake have been associated with decreased risks of heart disease, diabetes, stroke, several cancers, and possibly obesity, but vegetable intake is generally low. Preference is an important determinant of vegetable intake, and food preferences are initiated early in life, ...

Market Entry, Product Quality And Price Competition

Directory of Open Access Journals (Sweden)

Mathur Sameer

2015-08-01

Full Text Available We study an entrant firm’s product quality choice and the price competition arising between the entrant and the incumbent firm. We show that the entrant firm should introduce a relatively higher (lower quality than the incumbent firm when the consumers’ valuation for quality is sufficiently large (small. We also study how the incumbent firm modifies its price in response to the ensuing price competition. We find that the incumbent firm should decrease its price. We also profile how the incumbent firm’s price non-linearly depends on consumers’ valuation for quality.

A Closed-Loop Supply Chain Problem with Retailing and Recycling Competition

Directory of Open Access Journals (Sweden)

Chuanchao Xu

2014-01-01

Full Text Available We investigate a durable product retailing and recycling problem in a closed-loop supply chain consisting of a single manufacturer and two competitive retailers, in which the manufacturer collects used products via retailers from the consumers and has sufficient channel power over the retailers to act as a Stackelberg leader; the retailers compete in retail products and recycling used products. In order to analyze the impact of retailing and recycling competitions on the profits of the manufacturer and the competitive retailers, two collection models (coordinated collection (Model C and decentralized collection (Model D are established, respectively. Then, based on game theory, we derive the optimal retail price, the optimal repurchase price, and the optimal profits of the manufacturer and the retailers. The managerial insights demonstrate that more intense retailing competition induces the increase of the manufacturer's profits in both forward and reverse channels and retailers' profits in the forward channel and the decrease of retailers' profits in the reverse channel, while more intense recycling competition induces the decrease of the profits of the manufacturer and retailers in both forward and reverse channels. Finally, numerical examples are given to illustrate the effectiveness of the proposed models.

COMPETITIVENESS AND COMPETITIVE ORIENTATIONS: EVALUATION OF STUDENTS

Directory of Open Access Journals (Sweden)

G. Z. Efimova

2017-01-01

Full Text Available Introduction. Education of a competitive student is a strategically significant problem of the system of higher education in modern social and economic conditions. Personal competitiveness and competitive orientations – priority quality of future expert for successful future professional experience.The aim of the present research is to study factors of competitive orientations formation and criteria for evaluation of competitiveness of student’s youth in the Russian society.Methodology and research methods. Results of theoretical researches of Russian and foreign researchers are generalized; secondary analysis of data based on results of sociological researches and analysis of official statistical data are carried out. The results of the sociological survey undertaken in 2017 on the basis of statistical methods were processed and studied by the instrumentality of IBM SPSS Statistics 23 program; 1196 students of institutions of higher and secondary vocational education of the Tyumen region took part.Results and scientific novelty. It is stated that senior students feel themselves more competitive. It is revealed that a quarter of students who took part in the survey, generally men, count themselves competitive. A continuous distance of goal-setting is recorded among these respondents; in every third case they have plans of professional growth for five and more years that allows them to build attractive competitive strategy.The level of the competitiveness is directly connected with such indicators as “social stratum”, “overall life satisfaction”, “self-esteem of health”, “tendency to lead a healthy lifestyle” and “the level of trust in the surrounding people”. Mostly the students oriented on competition look into the future with confidence and optimism.Respondents focused on the competitiveness were more tend to demonstrate their abilities and cause admiration, have a creative approach towards work, be ready for surprises

Estimation of the competitive conditions in the Czech banking sector

Directory of Open Access Journals (Sweden)

Daniel Stavárek

2011-01-01

Full Text Available The paper uses New Empirical Industrial Organization approach, especially Panzar-Rosse model to estimates the level of competition of the banking industry in the Czech Republic during the period 2001–2009. We apply Panzar-Rosse model to estimate H statistic for a panel of 15 banks, which represent almost 90 % of the market. This paper also measures and compares the degree of banking competition in two sub-periods, 2001–2005 and 2005–2009, in order to investigate development of the competitive structure of the Czech banking industry. We found that the market was in equilibrium during most of the estimation period, which is a necessary condition for sound evaluation of the competition level. While the market can be described as perfectly competitive in 2001–2005, the intensity of competition decreased after joining the EU in 2004 and the market can be characterized as one of monopolistic competition in 2005–2009. The monopolistic competition in the Czech banking market was also revealed if the full sample 2001–2009 is considered.

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.

Multiseasonal-multispectral remote sensing of phenological change for natural vegetation inventory. Ph.D. Thesis

Science.gov (United States)

Schrumpf, B. J. (Principal Investigator)

1975-01-01

The author has identified the following significant results. Variations in phenological development among plant species was noted, as well as the tendency for the seasonal appearance of some vegetation types to be dominated by the appearance of one or a few similarly developing species. Most of the common plants in the study area could be characterized by temporal aspects of their phenological development. There was a strong similarity among the spectral signatures of vegetation types in which the spectral return was dominated by green plant material. When the soil background dominated the spectral return from a vegetation stand, then the spectral radiance and the vegetation physiognomy were apparently related. When the deciduous shrubs lost their leaves, their spectral signature altered with a slight decrease of radiance in the visible wavelengths and a strong decrease in the near infrared. As the foliage of perennial grasses cured from August to November, its apparent green radiance remained unchanged, red radiance increased over 50 percent, and near infrared radiance decreased approximately 30 percent. A reflective mineral surface exhibited high radiance levels in all four bands, thus providing a marked contrast to the absorption characteristics of vegetation canopies.

Spatio-Temporal Change of Vegetation Coverage and its Driving Forces Based on Landsat Images: a Case Study of Changchun City

Science.gov (United States)

Dong, L.; Jiang, H.; Yang, L.

2018-04-01

Based on the Landsat images in 2006, 2011 and 2015, and the method of dimidiate pixel model, the Normalized Difference Vegetation Index (NDVI) and the vegetation coverage, this paper analyzes the spatio-temporal variation of vegetation coverage in Changchun, China from 2006 to 2015, and investigates the response of vegetation coverage change to natural and artificial factors. The research results show that in nearly 10 years, the vegetation coverage in Changchun dropped remarkably, and reached the minimum in 2011. Moreover, the decrease of maximum NDVI was significant, with a decrease of about 27.43 %, from 2006 to 2015. The vegetation coverage change in different regions of the research area was significantly different. Among them, the vegetation change in Changchun showed a little drop, and it decreased firstly and then increased slowly in Yushu, Nong'an and Dehui. In addition, the temperature and precipitation change, land reclamation all affect the vegetation coverage. In short, the study of vegetation coverage change contributes scientific and technical support to government and environmental protection department, so as to promote the coordinated development of ecology and economy.

Macauba: a promising tropical palm for the production of vegetable oil

Directory of Open Access Journals (Sweden)

Colombo Carlos Augusto

2018-01-01

Full Text Available The growing global demand for vegetable oils for food and for replacing fossil fuels leads to increased oilseeds production. Almost 122 of the current 187 million tons of vegetable oils produced in the world correspond to palm and soybean oils. The oil palm is cultivated in the tropical zone, in areas formerly occupied by forests, and soybean oil is a by-product of protein meal production. The diversification of raw materials for the vegetable oil market is thus strategic for both food and non-food sectors. Sources for vegetable oil should be economically competitive and provide sustainability indexes higher than that provided by oil palm and soybean. In this context, we describe the potential of Acrocomia aculeata, popularly known as macauba. Macauba is an American palm from the tropical zones which presents oil productivity and quality similar to that of the oil palm. It grows spontaneously in a wide range of environments and it is not very water demanding. Macauba palm has a high potential for oil production and for diversification of co-products with some potential of value aggregation. Such a perennial and sustainable species will probably fulfill the requirements to become an important new commercial oilseed crop.

How can natural gas markets be competitively organized

International Nuclear Information System (INIS)

Funk, C.

1992-01-01

In this paper it will be discussed how to most effectively give room to competitive forces in natural gas markets, given the traditional merchant pipeline as point of departure. Alternative models of organizing the market will be reviewed: we first consider decreasing barriers to entry and then analyze advantages and drawbacks of a third party access system. In this context different forms of implementing a competitive market for transportation capacity and coordinating it with gas trade are discussed, among them a simultaneous auction of gas and transmission capacity. Finally a hub system of point markets in conjunction with third party access will be suggested to allow for competitive markets for gas and transportation service. 33 refs

A comparative study of competitiveness between different genotypes of weedy rice (Oryza sativa) and cultivated rice.

Science.gov (United States)

Dai, Lei; Dai, Weimin; Song, Xiaoling; Lu, Baorong; Qiang, Sheng

2014-01-01

Competition from weedy rice can cause serious yield losses to cultivated rice. However, key traits that facilitate competitiveness are still not well understood. To explore the mechanisms behind the strong growth and competitive ability, replacement series experiments were established with six genotypes of weedy rice from different regions and one cultivated rice cultivar. (1) Weedy rice from southern China had the greatest impact on growth and yield of cultivated rice throughout the entire growing season. Weedy rice from the northeast was very competitive during the early vegetative stage while the competitive effects of eastern weedy rice were more detrimental at later crop-growth stages. (2) As the proportion of weedy rice increased, plant height, tillers, above-ground biomass, and yield of cultivated rice significantly declined; the crop always being at disadvantage regardless of proportion. (3) Weedy biotypes with greater diversity as estimated by their Shannon indexes were more detrimental to the growth and yield of cultivated rice. Geographic origin (latitude) of weedy rice biotype, its mixture proportion under competition with the crop and its genetic diversity are determinant factors of the outcome of competition and the associated decline in the rice crop yield. © 2013 Society of Chemical Industry. © 2013 Society of Chemical Industry.

Health Risk Assessment of Vegetables Grown on the Contaminated Soils in Daye City of Hubei Province, China

Directory of Open Access Journals (Sweden)

Jun Yang

2017-11-01

Full Text Available China is an agriculturally-producing country and the safety of its vegetables will have an extensive attention at home and abroad. Recently, contamination of soils and vegetables caused by mining activities is of great social concern because of the potential risk to human health, especially to the residents whom live near metal or metalloid mines. In this study, 18 topsoil and 141 vegetable samples were collected from the contaminated areas in Daye City Hubei Province, China and the concentrations of copper (Cu, zinc (Zn, arsenic (As, cadmium (Cd and lead (Pb were analyzed. A self-designed questionnaire was assigned to obtain the exposure scenario and the USEPA health risk assessment model was adopted to assess two type of risks (non-carcinogenic risks and carcinogenic risks of vegetables to humans. The results showed that the average contents of metal(loids in soils exceeded the background value of Daye City. The average contents of metal(loids, especially As, Cd, Pb, in three kinds of vegetables were significantly higher than the permissible values based on Chinese national standard. Leafy vegetables had relatively higher concentrations and the transfer factors of As (0.015, Cd (0.080 and Pb (0.003 were comparable to leguminous and fruit vegetables. Leguminous vegetables had relatively higher concentrations and transfer factors of Cu (0.032 and Zn (0.094 than leafy and fruit vegetables. The transfer factors from soil to plants follows a decreasing order as Cd (0.068, Zn (0.047 > Cu (0.023 > As (0.006, Pb (0.002. Furthermore, health risk assessment revealed the following results: the non-carcinogenic risk decreased in the order of children, adult, adolescent, while the carcinogenic risk followed a decreasing order of adult, adolescent, children; the calculated carcinogenic and non-carcinogenic risk of the metal(loids by vegetable consumption decreased in the order of leafy vegetables > fruit vegetables > leguminous vegetables. The relatively

The role of vegetation in shaping dune morphology

Science.gov (United States)

Duran Vinent, O.; Moore, L. J.; Young, D.

2012-12-01

Aeolian dunes naturally emerge under strong winds and sufficient sand supply. They represent the most dynamical feature of the arid and/or coastal landscape and their evolution has the potential to either increase desertification or reduce coastal vulnerability to storms. Although large-scale dune morphology mainly depends on the wind regime and sand availability, vegetation plays an important role in semiarid and/or coastal areas. It is well known that under certain conditions vegetation is able to stabilize dunes, driving a morphological transformation from un-vegetated mobile crescent dunes to static vegetated "parabolic" dunes, de facto paralyzing desertification and initiating land recovery. Furthermore, vegetation is also the primary ingredient in the formation of coastal foredunes, which determine vulnerability to storms, as low dunes are prone to storm-induced erosion and overwash. In both cases, the coupling of biological and geomorphic (physical) processes, in particular vegetation growth and sand transport, governs the evolution of morphology. These processes were implemented in a computational model as part of a previous effort. It was shown that, for a migrating dune, this coupling leads to a negative feedback for dune motion, where an ever denser vegetation implies ever lesser sand transport. The model also predicted the existence of a "mobility index", defined by the vegetation growth rate to sand erosion rate ratio, that fully characterizes the morphological outcome: for indices above a certain threshold biological processes are dominant and dune motion slows after being covered by plants; for lower indices, the physical processes are the dominant ones and the dune remains mobile while vegetation is buried or rooted out. Here, we extend this model to better understand the formation of coastal dunes. We include new physical elements such as the shoreline and water table, as well as different grass species and potential competition among them

Do shallow soil, low water availability, or their combination increase the competition between grasses with different root systems in karst soil?

Science.gov (United States)

Zhao, Yajie; Li, Zhou; Zhang, Jing; Song, Haiyan; Liang, Qianhui; Tao, Jianping; Cornelissen, Johannes H C; Liu, Jinchun

2017-04-01

Uneven soil depth and low water availability are the key limiting factors to vegetation restoration and reconstruction in limestone soils such as in vulnerable karst regions. Belowground competition will possibly increase under limited soil resources. Here, we investigate whether low resource availability (including shallow soil, low water availability, and shallow soil and low water availability combined) stimulates the competition between grasses with different root systems in karst soil, by assessing their growth response, biomass allocation, and morphological plasticity. In a full three-way factorial blocked design of soil depth by water availability by neighbor identity, we grew Festuca arundinacea (deep-rooted) and Lolium perenne (shallow-rooted) under normal versus shallow soil depth, high versus low water availability, and in monoculture (conspecific neighbor) versus mixture (neighbor of the other species). The key results were as follows: (1) total biomass and aboveground biomass in either of the species decreased with reduction of resources but were not affected by planting patterns (monoculture or mixture) even at low resource levels. (2) For F. arundinacea, root biomass, root mass fraction, total root length, and root volume were higher in mixture than in monoculture at high resource level (consistent with resource use complementarity), but lower in mixture than in monoculture at low resource levels (consistent with interspecific competition). In contrast for L. perenne, either at high or low resource level, these root traits had mostly similar values at both planting patterns. These results suggest that deep-rooted and shallow-rooted plant species can coexist in karst regions under current climatic regimes. Declining resources, due to shallow soil, a decrease in precipitation, or combined shallow soil and karst drought, increased the root competition between plants of deep-rooted and shallow-rooted species. The root systems of deep-rooted plants may be

Competitive interactions among raptors in boreal forests.

Science.gov (United States)

Hakkarainen, Harri; Mykrä, Sakari; Kurki, Sami; Tornberg, Risto; Jungell, Sven

2004-11-01

We examined inter-specific interactions among goshawks ( Accipiter gentilis), common buzzards (Buteo buteo) and honey buzzards (Pernis apivorus) in western Finland in 1983-1996. Because goshawks are among the largest birds of prey species in boreal forests they may take over the nest of smaller and less-competitive forest-dwelling raptors when searching for suitable places for breeding. Accordingly, more than half of newly established goshawk territories were found on the territories previously occupied by the common buzzard and the honey buzzard. Otherwise, territory sharing between these species was rare. Fledgling production of honey buzzards was not associated with the presence of goshawks, probably owing to the almost 2 months later onset of breeding. This probably decreases competitive interactions between these two species. An intensive interference competition, instead, seemed to be evident between common buzzards and goshawks, because the fledgling production of common buzzards was decreased by 20% as a result of failures during incubation and nestling period in the vicinity (nests. Similarly, territory occupancy of common buzzards till the next breeding season was significantly reduced in the presence of goshawks. Relatively high proportions of occupied buzzard territories (17%) in the study area were shared by breeding goshawks on the same territory. This suggests that although their diets are dissimilar they inhabit similar habitats and might compete for the available prime nesting habitats within forest landscapes. In addition, goshawks benefit from taking over the complete nests of other raptors, imposing upon the original owners of the nest, because building a large stick nest is probably energetically costly. As a large raptor, the goshawk apparently has a competitive advantage over smaller ones, and may have an ever-increasing impact on smaller birds of prey, if there is a lack of sheltered forests inducing competition for the available nest sites.

Applicability of Vegetable Oils as a Wood Preservative

Directory of Open Access Journals (Sweden)

Eylem Dizman Tomak

2012-04-01

Full Text Available Conventional heavy duty wood preservatives have been banned or restricted for some applications due to their mammalian toxicity and their adverse effect on the environment. New, eco-friendly, but nevertheless still effective protection systems, is needed to protect wood in outdoors. Non-toxic vegetable oils can form of a protective layer on the surface of the wood cells which decrease water uptake of wood. For that reason, oils have a good potential as being a wood preservative. However, impregnation with vegetable oils is insufficient to impart adequate biological decay and termite resistance, and indeed the treatment may increase wood’s propensity to burn. In addition, a high level of oil absorption required for good protection make the process impractical and uneconomic to use. The efficiency of the treatment can be improved with using the biocides and oils together. Beside this, usage of modified oils can decrease the retention levels in wood. In this study, applicability of vegetable oils being one of the environment-friendly, biodegradable water repellents on wood treatments was reported. Furthermore, problems related to the use of oils for wood protection, and possible solutions for the problems were discussed.In this study, applicability of vegetable oils as one of the environment-friendly, biodegradable water repellents was reported. Furthermore, problems related to the use of oils for wood protection and possible solutions for the problems were discussed

An invasive plant alters phenotypic selection on the vegetative growth of a native congener.

Science.gov (United States)

Beans, Carolyn M; Roach, Deborah A

2015-02-01

The ecological consequences of plant competition have frequently been tested, but the evolutionary outcomes of these interactions have gone largely unexplored. The study of species invasions can make an important contribution to this field of research by allowing us to watch ecological and evolutionary processes unfold as a novel species is integrated into a plant community. We explored the ecological and evolutionary impact of an invasive jewelweed, Impatiens glandulifera, on a closely related native congener, I. capensis and asked: (1) Does the presence of the invasive jewelweed alter the fitness of native jewelweed populations? (2) Does the invasive jewelweed affect the vegetative growth of the native congener? and (3) Does the invasive jewelweed alter phenotypic selection on the vegetative traits of the native congener? We used a greenhouse competition experiment, an invasive species removal field experiment, and a survey of natural populations. We show that when the invasive jewelweed is present, phenotypic selection favors native jewelweed individuals investing less in rapid upward growth and more in branching and fruiting potential through the production of nodes. This research demonstrates that invasive plants have the potential to greatly alter natural selection on native competitors. Studies investigating altered selection in invaded communities can reveal the potential evolutionary impact of invasive competitors, while deepening our understanding of the more general role of competition in driving plant evolution and permitting species coexistence. © 2015 Botanical Society of America, Inc.

The vegetation in the Biotest basin, Forsmark nuclear power plant, 1984-1986

International Nuclear Information System (INIS)

Renstroem, S.; Svensson, Roger; Wigren-Svensson, M.

1990-01-01

In order to investigate if and how the vegetation has changed in consequence of the raised temperature in the biotest lake (which is the discharge area for the cooling water from the power plant), investigations of the distribution and production of macroscopic algae and higher vegetation have been carried out since 1974. This report presents the results from the period 1984-1986. The investigations have shown that not only the temperature, but also the absence of ice cover, the water stream through the biotest lake and the reduced exposition caused by the embankment, are of importance for the vegetation in the lake. The vegetation has changed in the following aspects: The area of the shore vegetation has been continuously increasing. In 1982 it was c. 6200 m 2 , 1984 it was c. 9850 m 2 and 1985 c. 11000 m 2 , mainly consisting of Phragmites communis. Most of the shore line is now occupied by vegetation. The standing crop was found to have decreased since the power plants started. 1980 there was 74 g/m 2 dry weight and in 1986 28 g/m 2 . Among the most important species of macroscopic underwater vegetation Chara spp and Potamogeton pectinatus show a decrease of standing crop while Cladophora glomerata and Vaucheria sp have increased since the investigation started. (authors)

Coatings for minimally processed fruits and vegetables

Science.gov (United States)

Fresh-cut fruit and vegetables are gaining increasing popularity and market share. Techniques to enhance stability of fresh cut produce are reviewed. Among these techniques, edibles coatings can provide protection against dehydration, microbial decay and decrease events related to physiological sene...

Body composition changes in female bodybuilders during preparation for competition.

Science.gov (United States)

van der Ploeg, G E; Brooks, A G; Withers, R T; Dollman, J; Leaney, F; Chatterton, B E

2001-04-01

To determine anthropometric and body composition changes in female bodybuilders during preparation for competition. There was an attempt to match subjects in the control and experimental groups for height and percentage body fat (%BF) for the initial test of this longitudinal study. Five competitive bodybuilders (-X +/- s.d.: 35.3 +/- 5.7 y; 167.3 +/- 3.7 cm; 66.38 +/- 6.30 kg; 18.3 +/- 3.5 %BF) and five athletic females (-X +/- s.d.: 30.9 +/- 13.0 y; 166.9 +/- 3.9 cm; 55.94 +/- 3.59 kg; 19.1 +/- 3.3 %BF) were recruited from advertisements in a bodybuilding newsletter and placed on sports centre noticeboards. The following measurements were conducted 12 weeks, 6 weeks and 3-5 d before the bodybuilders' competitions: anthropometric profile, body density by underwater weighing, total body water via deuterium dilution and bone mineral mass from a dual-energy X-ray absorptiometry scan. A combination of the last three measurements enabled the %BF to the determined by a four compartment model. A significant (P bodybuilders as they prepared for competition was primarily due to a reduction in fat mass (FM; -4.42 kg; 76.2%) as opposed to fat-free mass (FFM; -1.38 kg; 23.8%). The decreases in body mass and FM over the final 6 weeks were greater than those over the first 6 weeks. Their %BF decreased (P bodybuilders were accompanied by a significant decline (P bodybuilders presented with low %BFs at the start of the experiment, they still significantly decreased their body mass during the 12 week preparation for competition and most of this loss was due to a reduction in FM as opposed to FFM.

Analysis of vegetative homeostasis state of elite handball players

Directory of Open Access Journals (Sweden)

Y.N. Prystupa

2015-12-01

Full Text Available Purpose: to study characteristics and dynamic of elite handball players’ physiological indicators. Material: In experiment elite handball players (n=112, age 18-35 years participated. For determination of vegetative homeostasis state we analyzed variability of heart rhythm. The researches were conducted in laboratory conditions in rest state, in lying position during 5 minutes. Results: it was found that organism’s adaptation reactions to training loads go with different tension of regulation systems. At the end of competition period there appears hyper-kinetic syndrome. It witnessed insufficiency of means, which permit to maintain optimal regulation of cardio-vascular system and increase its functional potentials. Conclusions: indicators of cardio-vascular system and their dynamic w3itnessed maintaining of high level of handball players’ organism hemodynamic provisioning. High level of vegetative homeostasis pointed at certain degree of sportsmen’s fitness. Such state is sufficient for preservation of high potential of sympathetic -adrenaline system and overcoming of fatigue processes.

Development of Vegetation-Pervious Concrete in Grid Beam System for Soil Slope Protection

Science.gov (United States)

Bao, Xiaohua; Liao, Wenyu; Dong, Zhijun; Wang, Shanyong; Tang, Waiching

2017-01-01

One of the most efficient and environmentally friendly methods for preventing a landslide on a slope is to vegetate it. Vegetation-pervious concretes have a promising potential for soil protection. In this study, the vegetation-pervious concrete with low alkalinity was developed and studied. Combined with a grid beam structure system, the stability and strength between the vegetation-pervious concrete and base soil are believed to be enhanced effectively. For improving plant adaptability, the alkalinity of concrete can be decreased innovatively by adding a self-designed admixture into the cement paste. The effects of the admixture content on alkalinity and compressive strength of the hardened pervious concrete were investigated using X-ray diffraction (XRD) and compression test, respectively. Meanwhile, the permeability of the vegetation-pervious concrete was studied as well. Through comparing with ordinary pervious concrete, the effect of low alkaline pervious concrete on vegetation growth was investigated in a small-scale field for ten weeks. The test results indicated that the alkalinity of the cement samples decreased with the increase of admixture content, and the vegetation grew successfully on previous concrete. By increasing the admixture content to approximately 3.6%, the compressive strength of pervious concrete was more than 25 MPa. PMID:28772454

Grazing disturbance increases transient but decreases persistent soil seed bank.

Science.gov (United States)

Ma, Miaojun; Walck, Jeffrey L; Ma, Zhen; Wang, Lipei; Du, Guozhen

2018-04-30

Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole-year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0-5, 5-10, 10-15 cm) and for the whole depth (0-15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs. �

Renewable products, towards a new golden age of plants?; Produits renouvelables, vers un nouvel age d'or du vegetal?

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

Our industrial civilization was built on the use of fossil materials. It has only 3 centuries of existence, but the use of these non-renewable resources will necessary come to an end in a near future. However alternate ways already exist through the use of biomass-derived products. These proceedings summarize the main discussions that took place during the different round tables of this colloquium. The first round table makes a status of the shortage of fossil energy reserves and of the new challenges and solutions offered by plants and bio-energies. The second round table presents the reality of the market, products and consumption of todays renewable vegetal resources (environmental advantages, economic aspect and competitiveness of markets). The last round table deals with the role of governments in the political sustain of renewable vegetal products development (genetic research, financial aspects, incentives, competition with food agriculture). (J.S.)

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.

Do Gender Differences in Preferences for Competition Matter for Occupational Expectations?

DEFF Research Database (Denmark)

Kleinjans, Kristin J.

Occupational segregation by gender is prevalent and can explain some of the gender wage gap. I empirically investigate a possible explanation for this segregation: the gender difference in preferences for competition, which in recent experimental studies has been found to affect economic outcomes....... I find that women's greater distaste for competition decreases educational achievement. It can also explain part of the gender segregation in occupational fields. Specifically, accounting for distaste for competition reduces gender segregation in the fields of Law, Business & Management, Health...

Grazer-induced morphological defense in Scenedesmus obliquus is affected by competition against Microcystis aeruginosa.

Science.gov (United States)

Zhu, Xuexia; Wang, Jun; Lu, Yichun; Chen, Qinwen; Yang, Zhou

2015-07-30

The green alga Scenedesmus is known for its phenotypic plasticity in response to grazing risk. However, the benefits of colony formation induced by infochemicals from zooplankton should come with costs. That is, a tradeoff in benefit-to-cost ratios is likely under complex environmental conditions. In this study, we hypothesized that the coexistence of Scenedesmus and its competitors decreases the formation of anti-grazer colonies in Scenedesmus. Results demonstrated that the presence of a competitor Microcystis aeruginosa inhibited inducible defensive colony formation of Scenedesmus obliquus, and the established defensive colonies negatively affected the competitive ability of S. obliquus. The proportion of induced defensive colonies in cultures was dependent on the relative abundance of competitors. Under low competition intensity, large amount of eight-celled colonies were formed but at the cost of decreased competitive inhibition on M. aeruginosa. By contrast, defensive colony formation of S. obliquus slacked in the presence of high competition intensity to maintain a high displacement rate (competitive ability). In conclusion, S. obliquus exhibited different responses to potential grazing pressure under different intensities of competition, i.e., Scenedesmus morphological response to grazing infochemicals was affected by competition against Microcystis.

Short-term responses of wetland vegetation after liming of an Adirondack watershed

Energy Technology Data Exchange (ETDEWEB)

Mackun, I.R.; Leopold, D.J.; Raynal, D.J. (State Univ. of New York, Syracuse, NY (United States))

1994-08-01

Watershed liming has been suggested as a long-term mitigation strategy for lake acidity, particularly in areas subject to high levels of acidic deposition. However, virtually no information has been available on the impacts of liming on wetland vegetation. In 1989, 1100 Mg of limestone (83.5% CaCO[sub 3]) were aerially applied to 48% (100 ha) of the Woods Lake watershed in the west-central Adirondack region of New York as part of the first comprehensive watershed liming study in North America. We inventoried wetland vegetation in 1.0-m[sup 2] plots before liming and during the subsequent 2 yr. Within this period liming influenced the cover, frequency, or importance values of only 6 of 64 wetland taxa. The cover of Sphagnum spp. and of the cespitose sedge Carex interior decreased in control relative to limed plots, and cover of the rhizomatous sedge Cladium mariscoides increased nearly threefold in limed areas. These two sedges, which are relatively tall, are characteristic of more calcareous habitats. Cover of the grass Muhlenbergia uniflora, cover and importance were adversely affected or inhibited by lime. It is unclear whether liming directly inhibited the growth of these three small-statured species, or whether the adverse effects of lime were mediated through shifts in competitive interactions with other species. The limited responses that we observed to liming, along with changes that occurred in control plots over the study period, may indicate that in the short term watershed liming was no more of a perturbation than the environmental factors responsible for natural annual variation in wetland communities.

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.

Thirty years of change in the fynbos vegetation of the Cape of Good Hope Nature Reserve, South Africa

Directory of Open Access Journals (Sweden)

S. D. J. Privett

2001-09-01

Full Text Available This study used permanently marked 50 m: sites, surveyed at a 30 year interval, to provide a descriptive account of the temporal change in the fynbos vegetation of the Cape of Good Hope Nature Reserve. South Africa. Management records were used to examine the role of post-fire age. fire frequency and intensity, as well as biotic interactions (competition from overstorey proteoids and alien plants in influencing vegetation composition over this time period. The mean similarity in species composition of sites between surveys was 62%, indicating an average of nearly 40% turnover in species over the 30 year period. The main causes of this change included differences resulting from different stages in the post-fire succession as well as the impact of differential fire regimes (especially frequency effects. Competition from serotinous Proteaceae. which proved highly mobile after fire, as well as invasive Australian acacias also impacted on the composition of the vegetation over time. The study demonstrated that fynbos communities are temporally dynamic and that the changes over time in species composition are caused by a variety of processes. The study also provided evidence for the role of temporal diversity in contributing to the high species diversity in fynbos systems.

Arsenic uptake and speciation in vegetables grown under greenhouse conditions.

Science.gov (United States)

Smith, E; Juhasz, A L; Weber, J

2009-04-01

The accumulation of arsenic (As) by vegetables is a potential human exposure pathway. The speciation of As in vegetables is an important consideration due to the varying toxicity of different As species. In this study, common Australian garden vegetables were hydroponically grown with As-contaminated irrigation water to determine the uptake and species of As present in vegetable tissue. The highest concentrations of total As were observed in the roots of all vegetables and declined in the aerial portions of the plants. Total As accumulation in the edible portions of the vegetables decreased in the order radish > mung bean > lettuce = chard. Arsenic was present in the roots of radish, chard, and lettuce as arsenate (As(V)) and comprised between 77 and 92% of the total As present, whereas in mung beans, arsenite (As(III)) comprised 90% of the total As present. In aerial portions of the vegetables, As was distributed equally between both As(V) and As(III) in radish and chard but was present mainly as As(V) in lettuce. The presence of elevated As in vegetable roots suggests that As species may be complexed by phytochelatins, which limits As translocation to aerial portions of the plant.

Competitiveness - higher education

Directory of Open Access Journals (Sweden)

Labas Istvan

2016-03-01

Full Text Available Involvement of European Union plays an important role in the areas of education and training equally. The member states are responsible for organizing and operating their education and training systems themselves. And, EU policy is aimed at supporting the efforts of member states and trying to find solutions for the common challenges which appear. In order to make our future sustainable maximally; the key to it lies in education. The highly qualified workforce is the key to development, advancement and innovation of the world. Nowadays, the competitiveness of higher education institutions has become more and more appreciated in the national economy. In recent years, the frameworks of operation of higher education systems have gone through a total transformation. The number of applying students is continuously decreasing in some European countries therefore only those institutions can “survive” this shortfall, which are able to minimize the loss of the number of students. In this process, the factors forming the competitiveness of these budgetary institutions play an important role from the point of view of survival. The more competitive a higher education institution is, the greater the chance is that the students would like to continue their studies there and thus this institution will have a greater chance for the survival in the future, compared to ones lagging behind in the competition. Aim of our treatise prepared is to present the current situation and main data of the EU higher education and we examine the performance of higher education: to what extent it fulfils the strategy for smart, sustainable and inclusive growth which is worded in the framework of Europe 2020 programme. The treatise is based on analysis of statistical data.

CONSUMER BEHAVIOR ON THE FRUITS AND VEGETABLES MARKET

Directory of Open Access Journals (Sweden)

Istudor Nicolae

2011-12-01

Full Text Available In the past years the intensification of competition has changed the way in which companies communicate with their customers. The main challenge doesn’t represent anymore to create good products but also to be able to sell them. The best marketing strategy of a company can be best developed if the needs and the behavior of the consumer are known. In this paper there are analyzed the results of a research about the behavior of consumer towards fruits and vegetables. The research was done in the period December 2010 – February 2011 on 146 respondents regarding the buying behavior of consumers at retailers. The focus in the research is put on the cognitive and emotional reactions consumers have when they make the buying decision and consisted out of an observation and a survey. In this article there are presented both aspects regarding the observed behavior towards fruits and vegetables and the motives which led to this behavior. Depending on these results, there are presented the implications of this behavior on the marketing strategy of a company.

Topographically-controlled site conditions drive vegetation pattern on inland dunes in Poland

Science.gov (United States)

Sewerniak, Piotr; Jankowski, Michał

2017-07-01

The inland dunes of Central Europe are commonly overplanted by Scots pine (Pinus sylvestris) monocultures in which the primary occurrence of the natural vegetation pattern is obliterated. We hypothesize that on naturally revegetated inland dunes the pattern is clear and driven by topographically-controlled site conditions. To test this hypothesis, we addressed the following research questions: (1) Does topography drive vegetation patterns on inland dunes and if so, what are main differences between vegetation in varying relief positions? (2) To what extent does topography involve the variability of microclimates and of soil properties, and how does the topographically-induced differentiation of these site conditions control vegetation patterns? We conducted interdisciplinary studies (applying floristic, pedological and microclimatic research techniques) on a naturally revegetated inland dune area situated on a military artillery training ground near Toruń, northern Poland. We investigated vegetation patterns with reference to three topographical position variants (north-facing slopes, south-facing slopes, and intra-dune depressions). We found distinct differences in vegetation characteristics covering the aforementioned topographical positions. This primarily concerned species composition of ground vegetation: Calluna vulgaris was dominant species on north-facing slopes, Corynephorus canescens on south-facing slopes, while Calamagrostis epigejos in intra-dune depressions. In comparison to dune slopes, the depressions were characterized by much higher biodiversity of vascular plant species. This followed the most favorable soil conditions for the existence of plants (higher moisture and nutrient pools) occurring in low topographical positions. However, tree succession was most advanced not in depressions, where the competitive impact of tall grasses on seedlings was recognized, but on north-facing slopes. Based on our results, we formulated some suggestions, which

How can natural gas markets be competitively organized

International Nuclear Information System (INIS)

Funk, C.

1992-01-01

In this paper it will be discussed how to most effectively give room to competitive forces in natural gas markets, given the traditional merchant pipeline as point of departure. Alternative models of organizing the market will be reviewed: we first consider decreasing barriers to entry and then analyse advantages and drawbacks of a third party access system. In this context different forms of implementing a competitive market for transportation capacity and coordinating it with gas trade are discussed, among them a simultaneous auction of gas and transmission capacity. Finally a hub system of point markets will be suggested to improve the currently implemented third party access system and to allow for competitive markets for gas and transportation service. 33 refs., 6 figs

Rotation-length effects of diverse levels of competition control and pre-commercial thinning on stand development and financial performance of loblolly pine in central Louisiana

Science.gov (United States)

Michael A. Blazier; A. Gordon Holley; Shaun M. Tanger; Terry R. Clason; Eric L. Taylor

2016-01-01

Long-term productivity of loblolly pine (Pinus taeda L.) plantations can be increased by early suppression of herbaceous and woody competing vegetation (Zutter and others 1986, Haywood 1994, Miller and others 2003a). The USDA Forest Service’s Competition Omission Monitoring Project (COMP) was designed to isolate influences of two major competition...

Recent change of vegetation growth trend in China

International Nuclear Information System (INIS)

Peng Shushi; Fang Jingyun; Piao Shilong; Chen, Anping; Xu Liang; Myneni, Ranga B; Cao Chunxiang; Pinzon, Jorge E; Tucker, Compton J

2011-01-01

Using satellite-derived normalized difference vegetation index (NDVI) data, several previous studies have indicated that vegetation growth significantly increased in most areas of China during the period 1982–99. In this letter, we extended the study period to 2010. We found that at the national scale the growing season (April–October) NDVI significantly increased by 0.0007 yr −1 from 1982 to 2010, but the increasing trend in NDVI over the last decade decreased in comparison to that of the 1982–99 period. The trends in NDVI show significant seasonal and spatial variances. The increasing trend in April and May (AM) NDVI (0.0013 yr −1 ) is larger than those in June, July and August (JJA) (0.0003 yr −1 ) and September and October (SO) (0.0008 yr −1 ). This relatively small increasing trend of JJA NDVI during 1982–2010 compared with that during 1982–99 (0.0012 yr −1 ) (Piao et al 2003 J. Geophys. Res.—Atmos. 108 4401) implies a change in the JJA vegetation growth trend, which significantly turned from increasing (0.0039 yr −1 ) to slightly decreasing ( − 0.0002 yr −1 ) in 1988. Regarding the spatial pattern of changes in NDVI, the growing season NDVI increased (over 0.0020 yr −1 ) from 1982 to 2010 in southern China, while its change was close to zero in northern China, as a result of a significant changing trend reversal that occurred in the 1990s and early 2000s. In northern China, the growing season NDVI significantly increased before the 1990s as a result of warming and enhanced precipitation, but decreased after the 1990s due to drought stress strengthened by warming and reduced precipitation. Our results also show that the responses of vegetation growth to climate change vary across different seasons and ecosystems.

Recent Change of Vegetation Growth Trend in China

Science.gov (United States)

Peng, Shushi; Chen, Anping; Xu, Liang; Cao, Chunxiang; Fang, Jingyun; Myneni, Ranga B.; Pinzon, Jorge E.; Tucker, COmpton J.; Piao, Shilong

2011-01-01

Using satellite-derived normalized difference vegetation index (NDVI) data, several previous studies have indicated that vegetation growth significantly increased in most areas of China during the period 1982-99. In this letter, we extended the study period to 2010. We found that at the national scale the growing season (April-October) NDVI significantly increased by 0.0007/yr from 1982 to 2010, but the increasing trend in NDVI over the last decade decreased in comparison to that of the 1982-99 period. The trends in NDVI show significant seasonal and spatial variances. The increasing trend in April and May (AM) NDVI (0.0013/yr is larger than those in June, July and August (JJA) (0.0003/yr) and September and October (SO) (0.0008/yr). This relatively small increasing trend of JJA NDVI during 1982-2010 compared with that during 1982-99 (0.0012/yr) (Piao et al 2003 J. Geophys. Res.-Atmos. 108 4401) implies a change in the JJA vegetation growth trend, which significantly turned from increasing (0.0039/yr) to slightly decreasing (0:0002/yr) in 1988. Regarding the spatial pattern of changes in NDVI, the growing season NDVI increased (over 0.0020/yr) from 1982 to 2010 in southern China, while its change was close to zero in northern China, as a result of a significant changing trend reversal that occurred in the 1990s and early 2000s. In northern China, the growing season NDVI significantly increased before the 1990s as a result of warming and enhanced precipitation, but decreased after the 1990s due to drought stress strengthened by warming and reduced precipitation. Our results also show that the responses of vegetation growth to climate change vary across different seasons and ecosystems.

Furan formation during storage and reheating of sterilised vegetable purées.

Science.gov (United States)

Palmers, Stijn; Grauwet, Tara; Buvé, Carolien; Van de Vondel, Lore; Kebede, Biniam T; Hendrickx, Marc E; Van Loey, Ann

2015-01-01

To this day, research for furan mitigation has mostly targeted the levels of food production and handling of prepared foods by the consumer. However, part of the furan concentrations found in commercially available food products might originate from chemical deterioration reactions during storage. A range of individual vegetable purées was stored at two different temperatures to investigate the effects of storage on the furan concentrations of shelf-stable, vegetable-based foods. After 5 months of storage at 35°C (temperature-abuse conditions), a general increase in furan concentrations was observed. The furan formation during storage could be reduced by storing the vegetable purées at a refrigerated temperature of 4°C, at which the furan concentrations remained approximately constant for at least 5 months. Following storage, the vegetable purées were briefly reheated to 90°C to simulate the effect of the final preparation step before consumption. Contrary to storage, furan concentrations decreased as a result of evaporative losses. Both refrigerated storage and the reheating step prior to consumption showed the potential of mitigation measures for furan formation in vegetable-based foods (e.g. canned vegetables, ready-to-eat soups, sauces or baby foods). Next to furan, the vegetable purées were analysed for 2- and 3-methylfuran. Tomato was very susceptible to the formation of both alkylated derivatives of furan, as opposed to the other vegetables in this study. Methylfuran concentrations rapidly decreased during storage, which was contrary to the results observed for furan.

Improvement of Technological Properties of a Vegetal Tanning Agent in Gas Discharge Plasma

Science.gov (United States)

Khairullin, A. K.; Voznesensky, E. F.; Rakhmatullina, G. R.; Sabirov, A. M.; Tikhonova, N. V.

2017-11-01

The article considers the possibility of modification of the vegetal tanning agent quebracho in the plasma of a radio-frequency induction discharge at low pressure. It is established that plasma treatment leads to a decrease in the size of colloid fractions and a decrease in the molecular weight, while the functionality of the vegetal tanning agent is preserved. Application of the obtained product in the process of leather retanning allows improving its physical, mechanical and consumer properties.

U.S. masters track participation reveals a stable sex difference in competitiveness.

Science.gov (United States)

Deaner, Robert O; Addona, Vittorio; Mead, Michael P

2014-10-06

It is well established that men are more likely than women to engage in direct competition, but it is unclear if this reflects social structural conditions or evolved predispositions. These hypotheses can be addressed by quantifying competitiveness in sports and testing if the sex difference is decreasing over time in the U.S., a society where social roles have converged. Study 1 assessed participation and the occurrence of relatively fast performances by masters runners (40-74 years old) at recent road races and track meets. Fast performances occurred over 20 times more often at track meets than at road races. Women comprised 55% of finishers at roads races but only 15-28% of finishers at track meets. Thus, the sex difference in masters track participation can serve as a measure of the sex difference in competitiveness. Study 2 used data from national championship meets and yearly rankings lists to test whether the sex difference in masters track participation decreased from 1988-2012. The sex difference decreased overall, but there was no evidence of change since the late 1990s. Therefore, the sex difference in the willingness to engage in direct sports competition appears to reflect both social structural conditions and evolved predispositions.

How winning changes motivation in multiphase competitions.

Science.gov (United States)

Huang, Szu-Chi; Etkin, Jordan; Jin, Liyin

2017-06-01

What drives motivation in multiphase competitions? Adopting a dynamic approach, this research examines how temporary standing-being ahead of (vs. behind) one's opponent-in a multiphase competition shapes subsequent motivation. Six competitions conducted in the lab and in the field demonstrate that the impact of being ahead on contestants' motivation depends on when (i.e., in which phase of the competition) contestants learn they are in the lead. In the early phase, contestants are concerned about whether they can win; being ahead increases motivation by making winning seem more attainable. In the later phase, however, contestants are instead driven by how much additional effort they believe they need to invest; being ahead decreases motivation by reducing contestants' estimate of the remaining effort needed to win. Temporary standing thus has divergent effects on motivation in multiphase competitions, driven by a shift in contestants' main concern from the early to the later phase and thus the meaning they derive from being ahead of their opponent. By leveraging insights gained from approaching individuals' self-regulation as a dynamic process, this research advances understanding of how motivation evolves in a unique interdependent self-regulatory context. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Reflections on Competition, Competition Regulation and the Current Crises

DEFF Research Database (Denmark)

Buch-Hansen, Hubert; Wigger, Angela

2013-01-01

competition came to enjoy such an exalted status in Europe and then challenges conventional wisdom by bringing into focus the downsides of competition. It argues that excessive competition and neoliberal competition regulation have contributed to intensify the economic, political, social and environmental...

The evolution of enterprises in the global network competition

OpenAIRE

Borghoff,Thomas; Welge,Martin K.

2001-01-01

The globalization of a company is embedded in the globalization of its task environment. This process can be described as a co-evolutionary process of a social system in its environment. A historical view of the globalization of competition seems to prove that it can be interpreted as an evolutionary process of differentiation and integration that is reinforced by the decreasing rigidity of boundaries. A liquefaction of competition" can be observed, in which an increasing number of autonomous...

Renewable products, towards a new golden age of plants?; Produits renouvelables, vers un nouvel age d'or du vegetal?

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

Our industrial civilization was built on the use of fossil materials. It has only 3 centuries of existence, but the use of these non-renewable resources will necessary come to an end in a near future. However alternate ways already exist through the use of biomass-derived products. These proceedings summarize the main discussions that took place during the different round tables of this colloquium. The first round table makes a status of the shortage of fossil energy reserves and of the new challenges and solutions offered by plants and bio-energies. The second round table presents the reality of the market, products and consumption of todays renewable vegetal resources (environmental advantages, economic aspect and competitiveness of markets). The last round table deals with the role of governments in the political sustain of renewable vegetal products development (genetic research, financial aspects, incentives, competition with food agriculture). (J.S.)

Menu-engineering in restaurants - adapting portion sizes on plates to enhance vegetable consumption

NARCIS (Netherlands)

Reinders, Machiel J.; Huitink, Marlijn; Dijkstra, S.C.; Maaskant, Anna J.; Heijnen, Joris

2017-01-01

Background: The aim of this research was to investigate whether increased portion sizes of vegetables and decreased portion sizes of meat on main dishes increased the amount of vegetables consumed in a real-life restaurant setting without affecting customer satisfaction. The participants were

Resource competition in plant invasions: emerging patterns and research needs.

Science.gov (United States)

Gioria, Margherita; Osborne, Bruce A

2014-01-01

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

Resource competition in plant invasions: emerging patterns and research needs

Science.gov (United States)

Gioria, Margherita; Osborne, Bruce A.

2014-01-01

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species. PMID

Effect of storage temperature and time on the vitamin C contents of selected fruits and vegetables

International Nuclear Information System (INIS)

Firdous, S.; Abdullah, N.; Alim-un-Nisa; Ejaz, N.

2010-01-01

The vitamin C contents of 5 fruits and 7 vegetables, as a whole and in diced form, were determined by HPLC during cold storage. Results showed a decrease in vitamin C contents during 15 days refrigeration (7 deg. C) as well as freezing at -20 deg. C. It was found that fruits are more stable than vegetables since the rate of degradation of vitamin C was higher in vegetables as compared to fruits, either during freezing or refrigeration. During 15 days freezing, fruits showed a decrease of 41.05 - 51.44%, whereas, this loss augmented to 54.12 - 89.10% in vegetables. In addition to this, it was also observed that fruits and vegetables which have peels are less vulnerable to vitamin C degradation; the ratio of degradation of vitamin C in all the fruits studied and potato was not more than 51.44%. In fruits, apple was more susceptible and in vegetables, potato was more stable to vitamin C degradation. (author)

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.

Environmental structure and competitive scoring advantages in team competitions

Science.gov (United States)

Merritt, Sears; Clauset, Aaron

2013-10-01

In most professional sports, playing field structure is kept neutral so that scoring imbalances may be attributed to differences in team skill. It thus remains unknown what impact environmental heterogeneities can have on scoring dynamics or competitive advantages. Applying a novel generative model of scoring dynamics to roughly 10 million team competitions drawn from an online game, we quantify the relationship between the structure within a competition and its scoring dynamics, while controlling the impact of chance. Despite wide structural variations, we observe a common three-phase pattern in the tempo of events. Tempo and balance are highly predictable from a competition's structural features alone and teams exploit environmental heterogeneities for sustained competitive advantage. Surprisingly, the most balanced competitions are associated with specific environmental heterogeneities, not from equally skilled teams. These results shed new light on the design principles of balanced competition, and illustrate the potential of online game data for investigating social dynamics and competition.

Impacts of tourism hotspots on vegetation communities show a higher potential for self-propagation along roads than hiking trails.

Science.gov (United States)

Wolf, Isabelle D; Croft, David B

2014-10-01

Vegetation communities along recreational tracks may suffer from substantial edge-effects through the impacts of trampling, modified environmental conditions and competition with species that benefit from disturbance. We assessed impacts on trackside vegetation by comparing high and low usage tourism sites at a 1-10 m distance from recreational tracks in a popular arid-lands tourism destination in South Australia. The central aim was quantification of the strengths and spatial extent of tourism impacts along recreational tracks with a qualitative comparison of roads and trails. Track-distance gradients were most prevalent at high usage sites. There, species community composition was altered, total plant cover decreased, non-native species cover increased, plant diversity increased or decreased (depending on the distance) and soil compaction increased towards recreational tracks. Roadside effects were greater and more pervasive than trailside effects. Further, plant diversity did not continuously increase towards the road verge as it did along trails but dropped sharply in the immediate road shoulder which indicated high disturbance conditions that few species were able to tolerate. To our knowledge, we are the first to demonstrate that the access mode to a recreation site influences the potential of certain impacts, such as the increase of non-native species, to self-perpetuate from their points of introduction to disjointed sites with a predisposition to disturbance. Due to this propulsion of impacts, the overall spatial extent of roadside impacts was far greater than initially apparent from assessments at the road verge. We discuss possible means of mitigating these impacts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Weed-crop competition effects on growth and yield of sugarcane planted using two methods

International Nuclear Information System (INIS)

Zafar, M.; Tanveer, A.; Cheema, Z.A.; Ashraf, M.

2010-01-01

Effect of planting techniques and weed-crop competition periods on yield potential of spring planted sugarcane variety HSF-240 was studied at the Ayub Agricultural Research Institute, Faisalabad, Pakistan. The experiment was laid out in RCBD with a split-plot arrangement, with four replications and net plot size of 3.6m x 10m. In the experiment, two planting techniques viz., 60 cm apart rows in flat sowing technique and 120 cm apart rows in trench sowing technique were randomized in main plots. Seven weed-crop competition periods viz., Zero (weed free), weed-crop competition for 45, 60, 75, 90, 105 days after sowing (DAS) and weedy check (full season weed-crop competition) were randomized in sub-plots. Sugarcane sown by trench method exhibited more leaf area index (LAI), average crop growth rate (ACGR) and yield contributing attributes. Trench sowing by yielding 72.22 and 75.08 t ha/sup -1/ stripped cane yields, significantly showed superiority over the flat sowing, which gave 64.13 and 66.04 t ha/sup -1/ stripped cane yields in 2005-06 and 2006- 07, respectively. Generally, there was an increase in weed population and biomass but decrease in leaf area index, crop growth rate and yield components with an increase in weed-crop competition period. A decrease of 10.06, 17.90, 22.42, 28.65, 37.64 and 56.89% in stripped cane yield was observed for weed-crop competition periods of 45, 60, 75, 90, 105 DAS and weedy check as compared with zero competition in 2005-06, respectively. In 2006-07, the respective decrease in stripped cane yield was 9.84, 18.76, 22.92, 27.98, 38.75, and 54.98%. Trench sowing at 1.2 m row spacing proved better sowing technique and 45 DAS was the critical period of weed-crop competition. (author)

Market Structure in the Context of Developing Competitive Strategy

Directory of Open Access Journals (Sweden)

Algirdas Krivka

2011-04-01

Full Text Available The abstract deals with the application of positioning strategies under the conditions of classical market structures. It is discovered that the assumptions of pure competition leave no space for M. Porter’s generic cost leadership and differentiation strategies to be applied. The enterprise’s actions, influencing five competitive forces and implementing generic strategies, are reasonable under the conditions of imperfect competition market structures. The game theory models, applied to oligopoly, indicate the close interaction of enterprises and interdependence of their strategic decisions: cost reduction and differentiation strategies not only increase the profit of the enterprise, implementing the strategy, but by affecting market price and residual demand decrease the competitor’s profit.Article in Lithuanian

Stand competition determines how different tree species will cope with a warming climate.

Directory of Open Access Journals (Sweden)

Laura Fernández-de-Uña

Full Text Available Plant-plant interactions influence how forests cope with climate and contribute to modulate species response to future climate scenarios. We analysed the functional relationships between growth, climate and competition for Pinus sylvestris, Quercus pyrenaica and Quercus faginea to investigate how stand competition modifies forest sensitivity to climate and simulated how annual growth rates of these species with different drought tolerance would change throughout the 21st century. Dendroecological data from stands subjected to thinning were modelled using a novel multiplicative nonlinear approach to overcome biases related to the general assumption of a linear relationship between covariates and to better mimic the biological relationships involved. Growth always decreased exponentially with increasing competition, which explained more growth variability than climate in Q. faginea and P. sylvestris. The effect of precipitation was asymptotic in all cases, while the relationship between growth and temperature reached an optimum after which growth declined with warmer temperatures. Our growth projections indicate that the less drought-tolerant P. sylvestris would be more negatively affected by climate change than the studied sub-Mediterranean oaks. Q. faginea and P. sylvestris mean growth would decrease under all the climate change scenarios assessed. However, P. sylvestris growth would decline regardless of the competition level, whereas this decrease would be offset by reduced competition in Q. faginea. Conversely, Q. pyrenaica growth would remain similar to current rates, except for the warmest scenario. Our models shed light on the nature of the species-specific interaction between climate and competition and yield important implications for management. Assuming that individual growth is directly related to tree performance, trees under low competition would better withstand the warmer conditions predicted under climate change scenarios but in

Changing Pattern and Relation with Technological Level of the Korean and Japanese Export Competitiveness

Directory of Open Access Journals (Sweden)

Yongyul Kim

2010-12-01

Full Text Available The purpose of this paper is to explore empirically whether export competitiveness of Korea and Japan has changed since 1990s. Unlike existing literature, we tried to grasp changing patterns of export competitiveness by new methodology such as belonging quadrant and moving direction, rather than simply showing its trend or comparison classified by industry. And we categorized 48 sectors into some technological levelsThe purpose of this paper is to explore empirically whether export competitiveness of Korea and Japan has changed since 1990s. Unlike existing literature, we tried to grasp changing patterns of export competitiveness by new methodology such as belonging quadrant and moving direction, rather than simply showing its trend or comparison classified by industry. And we categorized 48 sectors into some technological levels, then analyzed how the change of export competitiveness is distributed by each technological level. When seeing 'revealed comparative advantage' and 'trade specification index', we found considerable changes in export competitiveness. Competitiveness of Korea has rapidly improved while that of Japan has been continuously decreasing. Especially the gap of competitiveness between Korea and Japan has largely reduced around the midterm of 2000s. Shrinking of the gap in export competitiveness has begun from the latter half of 1990s and first half of 2000s. Change of export competitiveness shows different trend by technology level. Korea has gained more competitiveness than Japan in high and middle level of technology. Korea shows upward tendency of competitiveness in mid and high technology, while Japan in low technology. Competitiveness gap between Korea and Japan is rapidly decreasing since the late 1990s, and curtailment of the gap is mainly happening in the high level of technological capabilities.

Family income, food prices, and household purchases of fruits and vegetables in Brazil.

Science.gov (United States)

Claro, Rafael Moreira; Monteiro, Carlos Augusto

2010-12-01

To analyze the influence of family income and food prices on the participation of fruits and vegetables in the food purchases of Brazilian households. Data analyzed refers to the Household Budget Survey conducted by the Instituto Brasileiro de Geografia e Estatística on a probabilistic sample of 48,470 Brazilian households between 2002 and 2003. Fruit and vegetable participation in total food purchases was expressed as a percentage of total calories purchased and as calories from fruit and vegetables adjusted for total calories purchased. A multiple regression analysis was employed to estimate elasticity coefficients, controlling for sociodemographic variables and price of other foods. Fruit and vegetable participation in total food purchases increased as the price of these foods decreased, or as income increased. A 1% decrease in the price of fruit and vegetables would increase their participation by 0.79%, whereas a 1% increase in family income would increase participation by 0.27%. The effect of income tended to be smaller among higher income strata. Reducing the price of fruit and vegetables, either by supporting their production or through fiscal measures, is a promising public policy instrument, capable of increasing the participation of these foods in the diet of the Brazilian population.

Sustainable competitive advantage for accountable care organizations.

Science.gov (United States)

Macfarlane, Michael Alex

2014-01-01

In the current period of health industry reform, accountable care organizations (ACOs) have emerged as a new model for the delivery of high-quality and cost-effective healthcare. However, few ACOs operate in direct competition with one another, and the accountable care business model has yet to present a means of continually developing new marginal value for patients and network partners. With value-based purchasing and patient consumerism strengthening as market forces, ACOs must build organizational sustainability and competitive advantage to meet the value demands set by customers and competitors. This essay proposes a strategy, adapted from the disciplines of agile software development and Lean product development, through which ACOs can engage internal and external customers in the development of new products that will provide sustainability and competitive advantage to the organization by decreasing waste in development, promoting specialized knowledge, and closely targeting customer value.

Monitoring vegetation change in Abu Dhabi Emirate from 1996 to 2000 and 2004 using Landsat Satellite Imagery

International Nuclear Information System (INIS)

Starbuck, M.J.; Tamayo, J.

2007-01-01

In the fall of 2001, a study was initiated to investigate vegetation changes in the Abu Dhabi Emirates. The vast majority of vegetation present in the region is irrigated and analysis of vegetation change will support groundwater investigations in the region by indicating areas of increased water use. Satellite-based imaging systems provide a good source of data for such an analysis. The recent analysis was completed between February and November 2002 using Landsat 5 Thematic Mapper satellite imagery acquired in 1996 and Landsat 7 Enhanced Thematic Mapper Plus imagery acquired in 2000. These assessments were augmented in 2004with the study of Landsat 7 imagery acquired in early 2004. The total area of vegetation for each of seven study areas was calculated using the Normalized Difference Vegetation Index (NDVI) technique. Multiband image classification was used to differentiate general vegetation types. Change analysis consisted of simple NDVI image differencing and post-classification change matrices. Measurements of total vegetation are for the Abu Dhabi Emirate indicate an increase from 77,200 hectares in 1996 to 162,700 hectares in 2000 (110% increase). Based on comparison with manual interpretation of satellite imagery, the amount of under-reporting of irrigated land is estimated at about 15% of the actual area. From the assessment of 2004 Landset imagery, it was found that the growth of irrigated vegetation in most areas of Emirate had stabilized and had actually slightly decreased in some cases. The decreases are probably due to variability in the measurement technique and not due to actual decreases in area of vegetation. (author)

Connecting long term species changes and their water competitions in temperate forest Mt. Baegun, Rep. of Korea using hydrogen and oxygen stable isotope analysis

Science.gov (United States)

Jeon, J.; Lee, H.; Lee, M.; Song, W.; Byeon, S.; Lee, B.; Cho, S.; Park, J.; Kim, H. S.

2017-12-01

Many dynamic vegetation model simulations have predicted dramatic changes in species composition of temperate forests due to climate changes and successional reasons. Especially, conifer species are expected to lose their habitats and to be replaced by broadleaf species. Similarly, our more than 15-years-long 880 permenant plots tree survey data in Mt. Baegun, Rep. of Korea, showed substantial decrease of conifer species and their productivities and increase of broadleaved species. One of main reasons for these changes in species could be attributed to the water competition among tree species in the same stand. Therefore, we investigated the differences in water uptake scheme between conifer and broadleaf species from the temperate forests of Korea using stable isotopes. Six study plots showing high competition (conifers vs. broadleaf species) based on previous vegetation survey were chosen and the species-specific water uptake depth was estimated by measuring hydrogen(δ2H) and oxygen(δ18O) ratio from the xylem sap and leaves of individual species and by comparing them with those of soil water from 5 depths, (10, 30, 50, 100 and 120 cm), which extracted by lysimeter. The collection was conducted from April 2016 to Nov 2017. The conifer species included Pinus densiflora and Chamaecyparis obtusa vs. broadleaved species included Carpinus laxiflora, Prunus sargentii, Styrax obassia, Lindera erythrocarpa and Quercus species such as Q. mongolica, Q. serrata, Q. accuticima. Preliminary results showed the stable isotope signatures of soil water was increased from 10 cm to 30 cm, and then decreased gradually until 120 cm. In addition, current dominant canopy species, Chamaecyparis obtusa absorbed majority of their water from 10 to 30 cm depth. In comparison, current mid canopy but one of upcoming dominant species, Styrax obassia's major water source was 30 cm and deeper of soil. Our results could be essential for the prediction of species composition under climate change

The Impact of Observed Vegetation Changes on Land–Atmosphere Feedbacks During Drought

KAUST Repository

Meng, X. H.

2014-04-01

Moderate Resolution Imaging Spectroradiometer (MODIS)-derived vegetation fraction data were used to update the boundary conditions of the advanced research Weather Research and Forecasting (WRF) Model to assess the influence of realistic vegetation cover on climate simulations in southeast Australia for the period 2000–08. Results show that modeled air temperature was improved when MODIS data were incorporated, while precipitation changes little with only a small decrease in the bias. Air temperature changes in different seasons reflect the variability of vegetation cover well, while precipitation changes have a more complicated relationship to changes in vegetation fraction. Both MODIS and climatology-based simulation experiments capture the overall precipitation changes, indicating that precipitation is dominated by the large-scale circulation, with local vegetation changes contributing variations around these. Simulated feedbacks between vegetation fraction, soil moisture, and drought over southeast Australia were also investigated. Results indicate that vegetation fraction changes lag precipitation reductions by 6–8 months in nonarid regions. With the onset of the 2002 drought, a potential fast physical mechanism was found to play a positive role in the soil moisture–precipitation feedback, while a slow biological mechanism provides a negative feedback in the soil moisture–precipitation interaction on a longer time scale. That is, in the short term, a reduction in soil moisture leads to a reduction in the convective potential and, hence, precipitation, further reducing the soil moisture. If low levels of soil moisture persist long enough, reductions in vegetation cover and vigor occur, reducing the evapotranspiration and thus reducing the soil moisture decreases and dampening the fast physical feedback. Importantly, it was observed that these feedbacks are both space and time dependent.

Concentration and Competition in Turkish Banking Industry: The Evidence from 2000 to 2012

Directory of Open Access Journals (Sweden)

Serpil Kuzucu

2015-09-01

Full Text Available Banking industry worldwide has been transformed due to globalization, financial liberalization, technological developments, government policies, deregulation of financial services, financial crises and increase in mergers and acquisitions since 1980. With these changes, there is a trend towards decrease in the number of banks and increase in banking concentration. Increase in banking concentration might affect competition conditions in banking industry. The decrease in the number of banks and the increase in banking concentration dominate the Turkish banking industry after the banking crises in 2000 and 2001. This paper examines the relationship between concentration and competition in Turkish banking industry. I measure the size of banking concentration by concentration ratios and Herfindahl-Hirschman index with the data of commercial deposit banks in Turkey from 2000 to 2012. Competition degree is measured by using Panzar Rosse model. The results of the study suggest that there is no permanent relation between banking concentration and competition in Turkish banks.

From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae?

Directory of Open Access Journals (Sweden)

Natalia L Ruocco

2012-03-01

Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.

Sex-dependent components of the analgesia produced by athletic competition.

Science.gov (United States)

Sternberg, W F; Bokat, C; Kass, L; Alboyadjian, A; Gracely, R H

2001-02-01

Competing in various athletic events (track meet, basketball game, or fencing match) can produce analgesia to cold pressor stimuli in male and female college athletes compared with baseline assessments. This competition-induced analgesia has been attributed to the stress associated with competition, which has components related to both physical exercise and the cognitive aspects of competing. This study evaluated the analgesic effect of exercise-related stress, and that caused by the cognitively stressful components of competing independent of exercise. Cold pressor pain ratings were assessed after competition in a track meet and after treadmill exercise or sedentary video game competition in both athletes and nonathletes. As expected, competing in athletics resulted in a decrease in cold pressor ratings in both male and female athletes. Independent of athletic status, treadmill running induced analgesia in women, but not in males, whereas sedentary video game competition produced analgesia in men, but not in women. These findings suggest that different components of the competitive athletic experience might be responsible for the analgesic effects in a sex-dependent manner.

Salivary Biomarkers and Training Load during Training and Competition in Paralympic Swimmers.

Science.gov (United States)

Sinnott-O'Connor, Ciara; Comyns, Tom; Nevill, Alan M; Warrington, Giles

2017-11-28

Stress responses in athletes can be attributed to training and also competition, where increased physiological and psychological stress may negatively impact on performance and recovery. The aim of this study was to examine the relationship between training load and salivary biomarkers IgA, alpha-amylase (AA) and cortisol across a 16-week preparation phase and 10-day competition phase in Paralympic swimmers. Four Paralympic swimmers provided bi-weekly saliva samples during three training phases - 1) normal training, 2) intensified training and 3) taper as well as daily saliva samples in the 10 day Paralympic competition (2016 Paralympic Games). Training load (TL) was measured using session-RPE. Multi-level analysis identified a significant increase in sIgA (94.98 (27.69) μg.ml -1 ), sAA (45.78 (19.07) μg.ml -1 ) and salivary cortisol (7.92 (2.17) ng.ml) during intensified training concurrent with a 38.3% increase in TL. During taper phase, a 49.5% decrease in TL from the intensified training phase resulted in decrease in sIgA, sAA and salivary cortisol; however, all three remained higher than baseline levels. A further significant increase was observed during competition in sIgA (168.69(24.19) μg.ml -1 ), sAA (35.86(16.67) μg.ml -1 ) and salivary cortisol (10.49(1.89) ng.ml) despite a continued decrease (77.8%) in TL from taper phase. Results demonstrate performance in major competition such as Paralympic Games despite a noticeable reduction in TL induces a stress response in athletes. Due to elevated stress response observed, modifications to individual post-race recovery protocols may be required to enable athletes to maximise performance across all ten days of competition.

Retail competition

International Nuclear Information System (INIS)

1998-01-01

Retail competition as the cornerstone of a competitive electricity marketplace was the subject of the seventh in the series of policy discussion papers developed at the Market Design Conference. Concern was expressed that because of the complexities involved in market design and technical implementation, the retail competition may lag behind other elements of the implementation of the new market design. A variety of key issues were debated, including the role of physical versus financial contracts, the form of retail competition and financial settlement systems in the short term, the requirement to separate 'competitive' (metering, billing, maintenance, consumer education) from non-competitive' (the transmission wires) services and the role of municipal electric utilities. It was agreed that the IMO should play an important role in defining and enforcing the separation of services, and that as a general rule, the development of policy in this area should be guided by the principle of maximizing the potential for competition

Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna.

Science.gov (United States)

Zwerts, J A; Prins, H H T; Bomhoff, D; Verhagen, I; Swart, J M; de Boer, W F

2015-01-01

South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns.

Competitive intelligence as an enabler for firm competitiveness: An overview

Directory of Open Access Journals (Sweden)

Alexander Maune

2014-06-01

Full Text Available The purpose of this article is to provide an overview, from literature, about how competitive intelligence can be an enabler towards a firm’s competitiveness. This overview is done under the background of intense global competition that firms are currently experiencing. This paper used a qualitative content analysis as a data collection methodology on all identified journal articles on competitive intelligence and firm competitiveness. To identify relevant literature, academic databases and search engines were used. Moreover, a review of references in related studies led to more relevant sources, the references of which were further reviewed and analysed. To ensure reliability and trustworthiness, peer-reviewed journal articles and triangulation were used. The paper found that competitive intelligence is an important enabler of firm competitiveness. The findings from this paper will assist business managers to understand and improve their outlook of competitive intelligence as an enabler of firm competitiveness and will be of great academic value.

Terrestrial biosphere models need better representation of vegetation phenology: results from the North American Carbon Program Site Synthesis

Science.gov (United States)

Andrew D. Richardson; Ryan S. Anderson; M. Altaf Arain; Alan G. Barr; Gil Bohrer; Guangsheng Chen; Jing M. Chen; Philippe Ciais; Kenneth J. David; Ankur R. Desai; Michael C. Dietze; Danilo Dragoni; Steven R. Garrity; Christopher M. Gough; Robert Grant; David Hollinger; Hank A. Margolis; Harry McCaughey; Mirco Migliavacca; Russel K. Monson; J. William Munger; Benjamin Poulter; Brett M. Raczka; Daniel M. Ricciuto; Alok K. Sahoo; Kevin Schaefer; Hanqin Tian; Rodrigo Vargas; Hans Verbeeck; Jingfeng Xiao; Yongkang. Xue

2012-01-01

Phenology, by controlling the seasonal activity of vegetation on the land surface, plays a fundamental role in regulating photosynthesis and other ecosystem processes, as well as competitive interactions and feedbacks to the climate system. We conducted an analysis to evaluate the representation of phenology, and the associated seasonality of ecosystem-scale CO

Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms

Science.gov (United States)

Hanna, Cause; Foote, David; Kremen, Claire

2014-01-01

Plant–pollinator mutualisms are disrupted by a variety of competitive interactions between introduced and native floral visitors. The invasive western yellowjacket wasp, Vespula pensylvanica, is an aggressive nectar thief of the dominant endemic Hawaiian tree species, Metrosideros polymorpha. We conducted a large-scale, multiyear manipulative experiment to investigate the impacts of V. pensylvanica on the structure and behavior of the M. polymorpha pollinator community, including competitive mechanisms related to resource availability. Our results demonstrate that V. pensylvanica, through both superior exploitative and interference competition, influences resource partitioning and displaces native and nonnative M. polymorpha pollinators. Furthermore, the restructuring of the pollinator community due to V. pensylvanica competition and predation results in a significant decrease in the overall pollinator effectiveness and fruit set of M. polymorpha. This research highlights both the competitive mechanisms and contrasting effects of social insect invaders on plant–pollinator mutualisms and the role of competition in pollinator community structure.

Through the integration to the regulated market of fresh vegetables in Slovenia

Directory of Open Access Journals (Sweden)

Jože Podgoršek

2016-09-01

Full Text Available Research Question (RQ: Disconnectedness of Slovenian producers is reflected in a markedly disadvantageous position in purchasing and sales marketing. Therefore, we raised a research question about the possibilities for the creation of an optimal model for the integration of producers. Purpose: The purpose of the study is to determine the readiness of stakeholders in the chain of vegetable production for mutual cooperation. The aim of the research is to find the optimal model of vegetable producers' integration and/with other stakeholders. Method: We have come to the results through different research tools. We have analyzed questionnaires with MS Excel and Statgraphyc plus 4.0, having errected an organization model for the integration of growers through a system analysis, comparative analysis and with multicriterion decision-making method DEXi. We have verified these results by applying a method of participatory research. Results: We found in this research that primarily larger agricultural holdings, which produce vegetables, wish to cooperate more intensively with each other. Using the research tools, we have determined the optimal form of mutual cooperation between producers. It is an economic cluster. However, gradual organizing via an producer organization, in particular due to the financial support of the EU, is reasonable. Organization: Competitive advantages acquired as the result of interconnection of growers will be felt on any agricultural holding. Society: By improving the conditions for the marketing of vegetables, self-sufficiency in vegetables will also grow, which will undoubtedly increase the autonomy of society and its independence from food imports from elsewhere. Originality: The study has made an innovative approach to the organization of the optimal model of the integration of vegetable growers. Limitations/Future Research: The study is limited to the vegetable sector, for the other sectors a new study should be carried out.

Review: computer vision applied to the inspection and quality control of fruits and vegetables

Directory of Open Access Journals (Sweden)

Erick Saldaña

2013-12-01

Full Text Available This is a review of the current existing literature concerning the inspection of fruits and vegetables with the application of computer vision, where the techniques most used to estimate various properties related to quality are analyzed. The objectives of the typical applications of such systems include the classification, quality estimation according to the internal and external characteristics, supervision of fruit processes during storage or the evaluation of experimental treatments. In general, computer vision systems do not only replace manual inspection, but can also improve their skills. In conclusion, computer vision systems are powerful tools for the automatic inspection of fruits and vegetables. In addition, the development of such systems adapted to the food industry is fundamental to achieve competitive advantages.

Spatial and temporal functional changes in alpine summit vegetation are driven by increases in shrubs and graminoids.

Science.gov (United States)

Venn, Susanna; Pickering, Catherine; Green, Ken

2014-01-01

Classical approaches to investigating temporal and spatial changes in community composition offer only partial insight into the ecology that drives species distribution, community patterns and processes, whereas a functional approach can help to determine many of the underlying mechanisms that drive such patterns. Here, we aim to bring these two approaches together to understand such drivers, using an elevation gradient of sites, a repeat species survey and species functional traits. We used data from a repeat vegetation survey on five alpine summits and measured plant height, leaf area, leaf dry matter content and specific leaf area (SLA) for every species recorded in the surveys. We combined species abundances with trait values to produce a community trait-weighted mean (CTWM) for each trait, and then combined survey results with the CTWMs. Across the gradient of summits, more favourable conditions for plant growth (warmer, longer growing season) occurred at the lower elevations. Vegetation composition changes between 2004 and 2011 (according to non-metric multi-dimensional scaling ordination) were strongly affected by the high and increasing abundance of species with high SLA at high elevations. Species life-form categories strongly affected compositional changes and functional composition, with increasing dominance of tall shrubs and graminoids at the lower-elevation summits, and an overall increase in graminoids across the gradient. The CTWM for plant height and leaf dry matter content significantly decreased with elevation, whereas for leaf area and SLA it significantly increased. The significant relationships between CTWM and elevation may suggest specific ecological processes, namely plant competition and local productivity, influencing vegetation preferentially across the elevation gradient, with the dominance of shrubs and graminoids driving the patterns in the CTWMs.

Effects of glufosinate-ammonium on off crop vegetation--interim results.

Science.gov (United States)

De Snoo, G R; De Jong, F M; Van Der Poll, R J; Van Der Linden, M G

2001-01-01

In 2000 a field study was conducted at four different locations concerning the effects of low dosages of glufosinate-ammonium, a leaf acting herbicide, on off crop vegetation. Therefore species rich road verges and ditch banks not adapted to a history of herbicide use were sprayed twice with different dosages of glufosinate-ammonium, simulating drift (0, 2, 4, 16, 32 and 64% of the maximum field dose: 800 g a.i./ha). The parameters studied were short term phytotoxic effects and the effects on biomass, species cover and number of species in autumn (Braun-Blanquêt relevés). The results show significant phytotoxic effects at all dosages of glufosinate-ammonium on the non-target vegetation. The low concentrations (2 and 4%) had most impact when applied early in the season (9% average at the 2% dosage and 22% at 4% dosage, after the first spraying. At high dosages (32 and 64%) a decrease of the biomass of the vegetation was found in August. A comparison between treatments in August shows a small decrease in species number and cover in the 64% compared to the control. In the comparison between the spring and August relevés, the decrease in the mean number of species was significantly stronger in the treated plots than in the untreated ones of 4% and higher. For monocotyledons in all treatments except 16%, a significantly stronger decrease in species number was found compared to the untreated. For dicotyledons only the 64% dosage differed from the untreated. Only at the 64% treatment the total cover of species decreased more than in the untreated plots. Since drift percentages of 2-4% can be expected at 1-2 m from a treated plot it can be concluded that the use of glufosinate-ammonium could result in visible short term phytotoxic effects (max 22%) on off-crop vegetation such as ditch banks and verges. There are also indications that effects on the number and cover of species in autumn can occur. Because in future glufosinate-ammonium could be used on a large scale in

Effects of the energy and mining industry on management of national competitiveness

Directory of Open Access Journals (Sweden)

Peter Madzík

2016-04-01

influence of energy and mining industry on competitiveness over the last 40 years has increased, particularly in the case of countries with low or medium economic development, and it has decreased in developed countries. The resulting information about the intensity of the mutual relations might be useful for management of competitiveness and planning of strategic economic tools.

Vegetated dune morphodynamics during recent stabilization of the Mu Us dune field, north-central China

Science.gov (United States)

Xu, Zhiwei; Mason, Joseph A.; Lu, Huayu

2015-01-01

The response of dune fields to changing environmental conditions can be better understood by investigating how changing vegetation cover affects dune morphodynamics. Significant increases in vegetation and widespread dune stabilization over the years 2000-2012 are evident in high-resolution satellite imagery of the Mu Us dune field in north-central China, possibly a lagged response to changing wind strength and temperature since the 1970s. These trends provide an opportunity to study how dune morphology changes with increasing vegetation stabilization. Vegetation expansion occurs mainly by expansion of pre-existing patches in interdunes. As vegetation spreads from interdunes onto surrounding dunes, it modifies their shapes in competition with wind-driven sand movement, primarily in three ways: 1) vegetation anchoring horns of barchans transforms them to parabolic dunes; 2) vegetation colonizes stoss faces of barchan and transverse dunes, resulting in lower dune height and an elongated stoss face, with shortening of barchan horns; and 3) on transverse dunes, the lee face is fixed by plants that survive sand burial. Along each of these pathways of stabilization, dune morphology tends to change from more barchanoid to more parabolic forms, but that transformation is not always completed before full stabilization. Artificial stabilization leads to an extreme case of "frozen" barchans or transverse dunes with original shapes preserved by rapid establishment of vegetation. Observations in the Mu Us dune field emphasize the point that vegetation growth and aeolian sand transport not only respond to external factors such as climate but also interact with each other. For example, some barchans lose sand mass during vegetation fixation, and actually migrate faster as they become smaller, and vegetation growth on a barchan's lower stoss face may alter sand transport over the dune in a way that favors more rapid stabilization. Conceptual models were generalized for the

Competition under high and low nutrient levels among three grassland species occupying different positions in a successional sequence

NARCIS (Netherlands)

Schippers, P.; Snoeijing, I.; Kropff, M.J.

1999-01-01

To clarify the role of seasonal change, competitive response and nutrient availability in the competitive asymmetry of grassland species a competition experiment was conducted on Holcus lanatus, Anthoxanthum odoratum and Festuca ovina, which represent a successional sequence of decreasing nutrient

Apparent competition with an invasive plant hastens the extinction of an endangered lupine.

Science.gov (United States)

Dangremond, Emily M; Pardini, Eleanor A; Knight, Tiffany M

2010-08-01

Invasive plants may compete with native plants by increasing the pressure of native consumers, a mechanism known as "apparent competition." Apparent competition can be as strong as or stronger than direct competition, but the role of apparent competition has rarely been examined in biological invasions. We used four years of demographic data and seed-removal experiments to determine if introduced grasses caused elevated levels of seed consumption on native plant species in a coastal dune system in California, USA. We show that the endangered, coastal dune plant Lupinus tidestromii experiences high levels of pre-dispersal seed consumption by the native rodent Peromyscus maniculatus due to its proximity to the invasive grass, Ammophila arenaria. We use stage-structured, stochastic population models to project that two of three study populations will decline toward extinction under ambient levels of consumption. For one of these declining populations, a relatively small decrease in consumption pressure should allow for persistence. We show that apparent competition with an invasive species significantly decreases the population growth rate and persistence of a native species. We expect that apparent competition is an important mechanism in other ecosystems because invasive plants often change habitat structure and plant-consumer interactions. Possible implications of the apparent-competition mechanism include selective extinction of species preferred by seed consumers in the presence of an invasive species and biological homogenization of communities toward non-preferred native plant species.

Effects of climate change on forest vegetation in the northern Rockies

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.; Halofsky, Jessica E.; Peterson, David L.

2018-01-01

Increasing air temperature, through its influence on soil moisture, is expected to cause gradual changes in the abundance and distribution of tree, shrub, and grass species throughout the Northern Rockies, with drought tolerant species becoming more competitive. The earliest changes will be at ecotones between lifeforms (e.g., upper and lower treelines). Ecological disturbance, including wildfire and insect outbreaks, will be the primary facilitator of vegetation change, and future forest landscapes may be dominated by younger age classes and smaller trees. High-elevation forests will be especially vulnerable if disturbance frequency

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.

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.

Competitive Intelligence.

Science.gov (United States)

Bergeron, Pierrette; Hiller, Christine A.

2002-01-01

Reviews the evolution of competitive intelligence since 1994, including terminology and definitions and analytical techniques. Addresses the issue of ethics; explores how information technology supports the competitive intelligence process; and discusses education and training opportunities for competitive intelligence, including core competencies…

[Variation of forest vegetation carbon storage and carbon sequestration rate in Liaoning Province, Northeast China].

Science.gov (United States)

Zhen, Wei; Huang, Mei; Zhai, Yin-Li; Chen, Ke; Gong, Ya-Zhen

2014-05-01

The forest vegetation carbon stock and carbon sequestration rate in Liaoning Province, Northeast China, were predicted by using Canadian carbon balance model (CBM-CFS3) combining with the forest resource data. The future spatio-temporal distribution and trends of vegetation carbon storage, carbon density and carbon sequestration rate were projected, based on the two scenarios, i. e. with or without afforestation. The result suggested that the total forest vegetation carbon storage and carbon density in Liaoning Province in 2005 were 133.94 Tg and 25.08 t x hm(-2), respectively. The vegetation carbon storage in Quercus was the biggest, while in Robinia pseudoacacia was the least. Both Larix olgensis and broad-leaved forests had higher vegetation carbon densities than others, and the vegetation carbon densities of Pinus tabuliformis, Quercus and Robinia pseudoacacia were close to each other. The spatial distribution of forest vegetation carbon density in Liaoning Province showed a decrease trend from east to west. In the eastern forest area, the future increase of vegetation carbon density would be smaller than those in the northern forest area, because most of the forests in the former part were matured or over matured, while most of the forests in the later part were young. Under the scenario of no afforestation, the future increment of total forest vegetation carbon stock in Liaoning Province would increase gradually, and the total carbon sequestration rate would decrease, while they would both increase significantly under the afforestation scenario. Therefore, afforestation plays an important role in increasing vegetation carbon storage, carbon density and carbon sequestration rate.

Healthy Competition and Unsound Comparison: Reforming Educational Competition in Singapore

Science.gov (United States)

Christensen, Søren

2015-01-01

It is frequently claimed that the "competition state" responds to external competition by making competition increasingly central to its internal processes as well. This article discusses education reform in Singapore as departing from the opposite position. In Singapore "excessive" competition in education is now targeted by…

Will European agricultural policy for school fruit and vegetables improve public health? A review of school fruit and vegetable programmes.

Science.gov (United States)

de Sa, Joia; Lock, Karen

2008-12-01

For the first time, public health, particularly obesity, is being seen as a driver of EU agricultural policy. In 2007, European Ministers of Agriculture were asked to back new proposals for school fruit and vegetable programmes as part of agricultural reforms. In 2008, the European Commission conducted an impact assessment to assess the potential impact of this new proposal on health, agricultural markets, social equality and regional cohesion. A systematic review of the effectiveness of interventions to promote fruit and/or vegetable consumption in children in schools, to inform the EC policy development process. School schemes are effective at increasing both intake and knowledge. Of the 30 studies included, 70% increased fruits and vegetables (FV) intake, with none decreasing intake. Twenty-three studies had follow-up periods >1 year and provide some evidence that FV schemes can have long-term impacts on consumption. Only one study led to both increased fruit and vegetable intake and reduction in weight. One study showed that school fruit and vegetable schemes can also help to reduce inequalities in diet. Effective school programmes have used a range of approaches and been organized in ways which vary nationally depending on differences in food supply chain and education systems. EU agriculture policy for school fruits and vegetables schemes should be an effective approach with both public health and agricultural benefits. Aiming to increase FV intake amongst a new generation of consumers, it will support a range of EU policies including obesity and health inequalities.

Impact of dam-induced hydrological changes on riparian vegetation

Science.gov (United States)

Tealdi, Stefano; Camporeale, Carlo; Ridolfi, Luca

2010-05-01

the pre-dam condition: in the first one the mean discharge is kept constant and the coefficient of variation is changed, in the second one the opposite is made. In the first case, we find non negligible values of the percentage differences - of the order of 10-40% - and we note that they depend on the ratio Tg/Td, where Tg and Td are the typical timescales of growth and decay of the vegetation, respectively. The values collapse on different non monotone curves, depending on the Tg/Td ratio. In general, when the coefficient of variation increases, there is a widening, while when it decreases there is a narrowing. The non monotony makes possible the widening even in some situations with decreasing coefficient of variation. In the second case, i.e. maintaining constant the coefficient of variation and changing the mean discharge, the obtained values are again non negligible - up to 15% - and collapse on a nonlinear curve, for each Tg/Td ratio. The decrease in the mean discharge always brings to a narrowing. Finally, we note that the sum of the two percentage differences just explained gives a good approximation of the overall narrowing/widening consequent to a change of both the mean discharge and the coefficient of variation. Similar analyses are made for the total biomass along the transect and its temporal variability, and also for these variables we find nonlinear curves and great changes, of the order of 100-1000%. In conclusion, we propose a method to assess the impact of river regulation on the riparian vegetation and we quantify some of the changes promoted by a reservoir on the vegetation, highlighting how great they can be. Camporeale, C., Ridolfi, L., 2006. Riparian vegetation distribution induced by river flow variability: a stochastic approach. Water Resour. Res. 42.

Biological effects of fruit and vegetables.

Science.gov (United States)

Dragsted, Lars O; Krath, Britta; Ravn-Haren, Gitte; Vogel, Ulla B; Vinggaard, Anne Marie; Bo Jensen, Per; Loft, Steffen; Rasmussen, Salka E; Sandstrom, The late BrittMarie; Pedersen, Anette

2006-02-01

A strong and persistent effect of plant-derived foods on the prevention of lifestyle diseases has emerged from observational studies. Several groups of constituents in plants have been identified as potentially health promoting in animal studies, including cholesterol-lowering factors, antioxidants, enzyme inducers, apoptosis inducers etc. In human intervention studies the dose levels achieved tend to be lower than the levels found to be effective in animals and sampling from target organs is often not possible. A controlled dietary human intervention study was performed with forty-three volunteers, providing 600 g fruit and vegetables/d or in the controls a carbohydrate-rich drink to balance energy intake. Surrogate markers of oxidative damage to DNA, protein and lipids, enzymic defence and lipid metabolism were determined in blood and urine. It was found that a high intake of fruit and vegetables tends to increase the stability of lipids towards oxidative damage. Markers of oxidative enzymes indicate a steady increase in glutathione peroxidase (GPX1) activity in erythrocytes during intervention with fruit and vegetables but there is no effect on GPX1 transcription levels in leucocytes. No change occurs in glutathione-conjugating or -reducing enzyme activities in erythrocytes or plasma, and there are no effects on the transcription of genes involved in phase 2 enzyme induction or DNA repair in leucocytes. Fruit and vegetable intake decreases the level of total cholesterol and LDL-cholesterol, but does not affect sex hormones. In conclusion, it has been shown that total cholesterol and LDL-cholesterol, markers of peripheral lipid oxidation, and erythrocyte GPX1 activity are affected by high intakes of fruit and vegetables. This finding provides support for a protective role of dietary fruit and vegetables against CVD.

Globalization: the evolution of enterprises in the global network competition

OpenAIRE

Borghoff, Thomas; Welge, Martin K.

2001-01-01

The globalization of a company is embedded in the globalization of its task environment. This process can be described as a co-evolutionary process of a social system in its environment. A historical view of the globalization of competition seems to prove that it can be interpreted as an evolutionary process of differentiation and integration that is reinforced by the decreasing rigidity of boundaries. A liquefaction of competition" can be observed, in which an increasing number of autonomous...

Male crickets adjust ejaculate quality with both risk and intensity of sperm competition.

Science.gov (United States)

Simmons, Leigh W; Denholm, Amy; Jackson, Chantelle; Levy, Esther; Madon, Ewa

2007-10-22

Sperm competition theory predicts that males should increase their expenditure on the ejaculate with increasing risk of sperm competition, but decrease their expenditure with increasing intensity. There is accumulating evidence for sperm competition theory, based on examinations of testes size and/or the numbers of sperm ejaculated. However, recent studies suggest that ejaculate quality can also be subject to selection by sperm competition. We used experimental manipulations of the risk and intensity of sperm competition in the cricket, Teleogryllus oceanicus. We found that males produced ejaculates with a greater percentage of live sperm when they had encountered a rival male prior to mating. However, when mating with a female that presented a high intensity of sperm competition, males did not respond to risk, but produced ejaculates with a reduced percentage of live sperm. Our data suggest that males exhibit a fine-tuned hierarchy of responses to these cues of sperm competition.

Does density-dependent diversification mirror ecological competitive exclusion?

Directory of Open Access Journals (Sweden)

Melanie J Monroe

Full Text Available Density-dependence is a term used in ecology to describe processes such as birth and death rates that are regulated by the number of individuals in a population. Evolutionary biologists have borrowed the term to describe decreasing rates of species accumulation, suggesting that speciation and extinction rates depend on the total number of species in a clade. If this analogy with ecological density-dependence holds, diversification of clades is restricted because species compete for limited resources. We hypothesize that such competition should not only affect numbers of species, but also prevent species from being phenotypically similar. Here, we present a method to detect whether competitive interactions between species have ordered phenotypic traits on a phylogeny, assuming that competition prevents related species from having identical trait values. We use the method to analyze clades of birds and mammals, with body size as the phenotypic trait. We find no sign that competition has prevented species from having the same body size. Thus, since body size is a key ecological trait and competition does not seem to be responsible for differences in body size between species, we conclude that the diversification slowdown that is prevalent in these clades is unlikely due to the ecological interference implied by the term density dependence.

Psycho-vegetative status of children suffering from giardiasis

Directory of Open Access Journals (Sweden)

I.B. Yershova

2017-09-01

Full Text Available Background. The study of psycho-vegetative disorders in children with Giardia lamblia infection was the objective of the study. Materials and methods. The study involved 86 children with giardiasis aged 7–18 years. To evaluate the autonomic changes, there were applied a questionnaire by A. Wayne. The autonomic tone was determined by the table of Guillaume-Veyn, vegetative reactivity — using Dagnini-Aschner reflex, vegetative supply of reactivity — by means of orthostatic test. Psychological examination of children was conducted using the methodology “Personality disorder diagnosis” by Z. Karpenko, Rosenberg Self-Esteem Scale, Beck Depression Inventory. Results. 75.6 % of сhildren had signs of autonomic dysfunction syndrome, 41.9 % — the parasympathetic autonomic tone, 43.0 % — the vagotonic type of autonomic reactivity. Inadequate maintenance of vegetative reactivity was detected in 39.5 % of patients. Psychological testing showed uncertainty in 55.9 % of child­ren, anxiety — in 42.6 %, decrease in self-esteem — in 41.2 %; depression — in 38.2 %, isolation — in 27.9 %. Conclusions. Vegetative disorders in children with giardiasis occur in 75.6 % of cases. There is a tendency to vagotonia. Changes of psycho-functional status are manifested by increasing isolation, depression, anxiety.

Stable isotope and modelling evidence for CO2 as a driver of glacial–interglacial vegetation shifts in southern Africa

Directory of Open Access Journals (Sweden)

F. J. Bragg

2013-03-01

Full Text Available Atmospheric CO2 concentration is hypothesized to influence vegetation distribution via tree–grass competition, with higher CO2 concentrations favouring trees. The stable carbon isotope (δ13C signature of vegetation is influenced by the relative importance of C4 plants (including most tropical grasses and C3 plants (including nearly all trees, and the degree of stomatal closure – a response to aridity – in C3 plants. Compound-specific δ13C analyses of leaf-wax biomarkers in sediment cores of an offshore South Atlantic transect are used here as a record of vegetation changes in subequatorial Africa. These data suggest a large increase in C3 relative to C4 plant dominance after the Last Glacial Maximum. Using a process-based biogeography model that explicitly simulates 13C discrimination, it is shown that precipitation and temperature changes cannot explain the observed shift in δ13C values. The physiological effect of increasing CO2 concentration is decisive, altering the C3/C4 balance and bringing the simulated and observed δ13C values into line. It is concluded that CO2 concentration itself was a key agent of vegetation change in tropical southern Africa during the last glacial–interglacial transition. Two additional inferences follow. First, long-term variations in terrestrial δ13Cvalues are not simply a proxy for regional rainfall, as has sometimes been assumed. Although precipitation and temperature changes have had major effects on vegetation in many regions of the world during the period between the Last Glacial Maximum and recent times, CO2 effects must also be taken into account, especially when reconstructing changes in climate between glacial and interglacial states. Second, rising CO2 concentration today is likely to be influencing tree–grass competition in a similar way, and thus contributing to the "woody thickening" observed in savannas worldwide. This second inference points to the importance of experiments to

EDITORIAL: Physics competitions Physics competitions

Science.gov (United States)

Jordens, H.; Mathelitsch, L.

2010-07-01

This editorial opens the second special section on physics competitions in European Journal of Physics. In the first section last year, we asked for feedback on the idea of such a section and on the content of the articles. We received no answer whatsoever, which can be interpreted in two ways: the section is not interesting enough to raise motivation for feedback, or the reader is satisfied. Having no indication which scenario is the correct one, we are optimistic and favour the second. The section at hand contains three articles. Again, as last year, the organizer of the annual Olympiad reports on tasks and outcomes of this competition. The Olympiad took place in Merida, Mexico, and was by far the largest event with 316 contestants from 68 countries. Again, the predominance of Asian/Chinese students was manifest, showing how serious the training is taken by both their authorities and students. Unfortunately, the winners of the last International Young Physicists' Tournament (IYPT), the team from Korea, did not accept the offer to report on their prize-winning contribution. We are thankful that two students from Austria, who achieved second place with their team, took over and reported on the task which they presented in the finals of the competition. It connects the fields of sport and physics and explains a special move in skateboarding. The third contribution introduces a different competition, 'International Conference of Young Scientists'. On one hand, as in the Olympiad, it addresses individuals, not teams. On the other, as in the IYPT, students have several months to prepare and also the quality of the presentation is an important element of the judgment. In fact, this competition comes closer to real scientific research compared to the other events. Finally and again, we hope that this section will serve several purposes: To show the competitions as a very important tool in the support of gifted students. To raise awareness amongst university teachers, and

Attribution of trends in global vegetation greenness from 1982 to 2011

Science.gov (United States)

Zhu, Z.; Xu, L.; Bi, J.; Myneni, R.; Knyazikhin, Y.

2012-12-01

Time series of remotely sensed vegetation indices data provide evidence of changes in terrestrial vegetation activity over the past decades in the world. However, it is difficult to attribute cause-and-effect to vegetation trends because variations in vegetation productivity are driven by various factors. This study investigated changes in global vegetation productivity first, and then attributed the global natural vegetation with greening trend. Growing season integrated normalized difference vegetation index (GSI NDVI) derived from the new GIMMS NDVI3g dataset (1982-2011was analyzed. A combined time series analysis model, which was developed from simper linear trend model (SLT), autoregressive integrated moving average model (ARIMA) and Vogelsang's t-PST model shows that productivity of all vegetation types except deciduous broadleaf forest predominantly showed increasing trends through the 30-year period. The evolution of changes in productivity in the last decade was also investigated. Area of greening vegetation monotonically increased through the last decade, and both the browning and no change area monotonically decreased. To attribute the predominant increase trend of productivity of global natural vegetation, trends of eight climate time series datasets (three temperature, three precipitation and two radiation datasets) were analyzed. The attribution of trends in global vegetation greenness was summarized as relaxation of climatic constraints, fertilization and other unknown reasons. Result shows that nearly all the productivity increase of global natural vegetation was driven by relaxation of climatic constraints and fertilization, which play equally important role in driving global vegetation greenness.; Area fraction and productivity change fraction of IGBP vegetation land cover classes showing statistically significant (10% level) trend in GSI NDVIt;

INVENTORY DECISIONS WITH DECREASING PURCHASING COSTS

OpenAIRE

XIANGPEI HU; HUIMIN WANG; YUNZENG WANG

2012-01-01

Costs of many items drop systematically throughout their life-cycles, due to advances in technology and competition. Motivated by the management of service parts for some high-tech products, this paper studies inventory decisions for such items. In a periodic review setting with stochastic demand, we model the purchasing costs of successive periods as a stochastic and decreasing sequence. Unit selling price of the item is determined as some mark-up of the purchasing cost and, hence, will chan...

Choice architectural nudge interventions to promote vegetable consumption based on automatic processes decision-making

DEFF Research Database (Denmark)

Skov, Laurits Rohden; Friis Rasmussen, Rasmus; Møller Andersen, Pernille

2014-01-01

that had a default portion size of vegetable had he intended impact of increasing vegetable consumption. This emphasises the importance of portion sizes in out of home eating as well as underlines the effect of the one-unit bias. The remaining two nudges were not successful in increasing vegetable intake......, but promoted health by decreasing total energy intake which suggests that visual variety of fruit and greens prompts a healthy-eater subconscious behaviour....

Power market competition

International Nuclear Information System (INIS)

Kelly, J.

1998-01-01

In the Unites States the prospect of greater competition in wholesale power market was immediately eclipsed by talk of retail competition. Attempts to move to retail competition have been costly and complex. Prudent public policy and economic analyses suggest that retail competition not be implemented until it can first be demonstrated that effective competition exists in wholesale power markets [it

Lunabotics Mining Competition

Science.gov (United States)

Mueller, Rob; Murphy, Gloria

2010-01-01

This slide presentation describes a competition to design a lunar robot (lunabot) that can be controlled either remotely or autonomously, isolated from the operator, and is designed to mine a lunar aggregate simulant. The competition is part of a systems engineering curriculum. The 2010 competition winners in five areas of the competition were acknowledged, and the 2011 competition was announced.

Salivary Hormones Response to Preparation and Pre-competitive Training of World-class Level Athletes

Science.gov (United States)

Guilhem, Gaël; Hanon, Christine; Gendreau, Nicolas; Bonneau, Dominique; Guével, Arnaud; Chennaoui, Mounir

2015-01-01

This study aimed to compare the response of salivary hormones of track and field athletes induced by preparation and pre-competitive training periods in an attempt to comment on the physiological effects consistent with the responses of each of the proteins measured. Salivary testosterone, cortisol, alpha-amylase, immunoglobulin A (IgA), chromogranin A, blood creatine kinase activity, and profile of mood state were assessed at rest in 24 world-class level athletes during preparation (3 times in 3 months) and pre-competitive (5 times in 5 weeks) training periods. Total mood disturbance and fatigue perception were reduced, while IgA (+61%) and creatine kinase activity (+43%) increased, and chromogranin A decreased (−27%) during pre-competitive compared to preparation period. A significant increase in salivary testosterone (+9 to +15%) and a decrease in testosterone/cortisol ratio were associated with a progressive reduction in training load during pre-competitive period (P athletics training. PMID:26635619

Heavy metals in intensive greenhouse vegetable production systems along Yellow Sea of China

DEFF Research Database (Denmark)

Hu, Wenyou; Huang, Biao; Tian, Kang

2017-01-01

Recently, greenhouse vegetable production (GVP) has grown rapidly and counts a large proportion of vegetable production in China. In this study, the accumulation, health risk and threshold values of selected heavy metals were evaluated systematically. A total of 120 paired soil and vegetable...... relatively high concentrations and transfer factors of heavy metals. The accumulation of heavy metals in soils was affected by soil pH and soil organic matter. The calculated hazard quotients (HQ) of the heavy metals by vegetable consumption decreased in the order of leafy > rootstalk > fruit vegetables...... with hazard index (HI) values of 0.61, 0.33 and 0.26, respectively. The HI values were all below 1, which indicates that there is a low risk of greenhouse vegetable consumption. Soil threshold values (STVs) of heavy metals in GVP system were established according to the health risk assessment. The relatively...

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

Effects of projected climate change on vegetation in the Blue Mountains ecoregion, USA

Directory of Open Access Journals (Sweden)

Becky K. Kerns

2018-04-01

Full Text Available We used autecological, paleoecological, and modeling information to explore the potential effects of climate change on vegetation in the Blue Mountains ecoregion, Oregon (USA. Although uncertainty exists about the exact nature of future vegetation change, we infer that the following are likely to occur by the end of the century: (1 dominance of ponderosa pine and sagebrush will increase in many locations, (2 the forest-steppe ecotone will move upward in latitude and elevation, (3 ponderosa pine will be distributed at higher elevations, (4 subalpine and alpine systems will be replaced by grass species, pine, and Douglas-fir, (5 moist forest types may increase under wetter scenarios, (6 the distribution and abundance of juniper woodlands may decrease if the frequency and extent of wildfire increase, and (7 grasslands and shrublands will increase at lower elevations. Tree growth in energy-limited landscapes (high elevations, north aspects will increase as the climate warms and snowpack decreases, whereas tree growth in water-limited landscapes (low elevations, south aspects will decrease. Ecological disturbances, including wildfire, insect outbreaks, and non-native species, which are expected to increase in a warmer climate, will affect species distribution, tree age, and vegetation structure, facilitating transitions to new combinations of species and vegetation patterns. In dry forests where fire has not occurred for several decades, crown fires may result in high tree mortality, and the interaction of multiple disturbances and stressors will probably exacerbate stress complexes. Increased disturbance will favor species with physiological and phenological traits that allow them to tolerate frequent disturbance. Keywords: Climate change, Disturbance, Vegetation, Wildfire

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

Heterogeneous hydrogenation of vegetable oils : A literature review

NARCIS (Netherlands)

Veldsink, JW; Bouma, MJ; Schoon, NH; Beenackers, AACM

1997-01-01

Hardening of vegetable oils is reviewed from an engineering point of view. The present review focuses on kinetics of the hydrogenation and relevant transport and adsorption steps. It aims to contribute to accelerate new research to improve substantially on selectivities in general and a decrease of

Ecosystem response to removal of exotic riparian shrubs and a transition to upland vegetation

Science.gov (United States)

Reynolds, Lindsay V.; Cooper, David J.

2011-01-01

Understanding plant community change over time is essential for managing important ecosystems such as riparian areas. This study analyzed historic vegetation using soil seed banks and the effects of riparian shrub removal treatments and channel incision on ecosystem and plant community dynamics in Canyon de Chelly National Monument, Arizona. We focused on how seeds, nutrients, and ground water influence the floristic composition of post-treatment vegetation and addressed three questions: (1) How does pre-treatment soil seed bank composition reflect post-treatment vegetation composition? (2) How does shrub removal affect post-treatment riparian vegetation composition, seed rain inputs, and ground water dynamics? and (3) Is available soil nitrogen increased near dead Russian olive plants following removal and does this influence post-treatment vegetation? We analyzed seed bank composition across the study area, analyzed differences in vegetation, ground water levels, and seed rain between control, cut-stump and whole-plant removal areas, and compared soil nitrogen and vegetation near removed Russian olive to areas lacking Russian olive. The soil seed bank contained more riparian plants, more native and fewer exotic plants than the extant vegetation. Both shrub removal methods decreased exotic plant cover, decreased tamarisk and Russian olive seed inputs, and increased native plant cover after 2 years. Neither method increased ground water levels. Soil near dead Russian olive trees indicated a short-term increase in soil nitrogen following plant removal but did not influence vegetation composition compared to areas without Russian olive. Following tamarisk and Russian olive removal, our study sites were colonized by upland plant species. Many western North American rivers have tamarisk and Russian olive on floodplains abandoned by channel incision, river regulation or both. Our results are widely applicable to sites where drying has occurred and vegetation

Intensive ground vegetation growth mitigates the carbon loss after forest disturbance.

Science.gov (United States)

Zehetgruber, Bernhard; Kobler, Johannes; Dirnböck, Thomas; Jandl, Robert; Seidl, Rupert; Schindlbacher, Andreas

2017-01-01

Slow or failed tree regeneration after forest disturbance is increasingly observed in the central European Alps, potentially amplifying the carbon (C) loss from disturbance. We aimed at quantifying C dynamics of a poorly regenerating disturbance site with a special focus on the role of non-woody ground vegetation. Soil CO 2 efflux, fine root biomass, ground vegetation biomass, tree increment and litter input were assessed in (i) an undisturbed section of a ~ 110 years old Norway spruce stand, (ii) in a disturbed section which was clear-cut six years ago (no tree regeneration), and (iii) in a disturbed section which was clear-cut three years ago (no tree regeneration). Total soil CO 2 efflux was similar across all stand sections (8.5 ± 0.2 to 8.9 ± 0.3 t C ha -1  yr. -1 ). The undisturbed forest served as atmospheric C sink (2.1 t C ha -1  yr. -1 ), whereas both clearings were C sources to the atmosphere. The source strength three years after disturbance (-5.5 t C ha -1  yr. -1 ) was almost twice as high as six years after disturbance (-2.9 t C ha -1  yr. -1 ), with declining heterotrophic soil respiration and the high productivity of dense graminoid ground vegetation mitigating C loss. C loss after disturbance decreases with time and ground vegetation growth. Dense non-woody ground vegetation cover can hamper tree regeneration but simultaneously decrease the ecosystem C loss. The role of ground vegetation should be more explicitly taken into account in forest C budgets assessing disturbance effects.

Supply chain of perishables: how restaurants choose and relate with suppliers of vegetables

Directory of Open Access Journals (Sweden)

Gessuir Pigatto

2017-08-01

Full Text Available The increased meals outside has allowed the companies that offer the food service a increase in financial revenues, but increased the requirements for purchase of quality inputs. Thus, this article aims to analyze the perishables supply chain used by firms that operate in the food service, specifically the process of vegetables purchasing by small restaurants and their relationships with farming suppliers. Was utilized as analysis object, restaurants located in the northwestern regions of the State of São Paulo situated more than 600 km from the main supply vegetables center (CEAGESP. We chose a field research through data collection by semistructured questionnaires, applied in a personal interview with qualitative and quantitative data analysis. Although narrow, the relationship between the two chain links (restaurants and agricultural suppliers revealed to were positioned nearer to the market competitive than to the collaborative Market.

Product reformulation and nutritional improvements after new competitive food standards in schools.

Science.gov (United States)

Jahn, Jaquelyn L; Cohen, Juliana Fw; Gorski-Findling, Mary T; Hoffman, Jessica A; Rosenfeld, Lindsay; Chaffee, Ruth; Smith, Lauren; Rimm, Eric B

2018-04-01

In 2012, Massachusetts enacted school competitive food and beverage standards similar to national Smart Snacks. These standards aim to improve the nutritional quality of competitive snacks. It was previously demonstrated that a majority of foods and beverages were compliant with the standards, but it was unknown whether food manufacturers reformulated products in response to the standards. The present study assessed whether products were reformulated after standards were implemented; the availability of reformulated products outside schools; and whether compliance with the standards improved the nutrient composition of competitive snacks. An observational cohort study documenting all competitive snacks sold before (2012) and after (2013 and 2014) the standards were implemented. The sample included thirty-six school districts with both a middle and high school. After 2012, energy, saturated fat, Na and sugar decreased and fibre increased among all competitive foods. By 2013, 8 % of foods were reformulated, as were an additional 9 % by 2014. Nearly 15 % of reformulated foods were look-alike products that could not be purchased at supermarkets. Energy and Na in beverages decreased after 2012, in part facilitated by smaller package sizes. Massachusetts' law was effective in improving the nutritional content of snacks and product reformulation helped schools adhere to the law. This suggests fully implementing Smart Snacks standards may similarly improve the foods available in schools nationally. However, only some healthier reformulated foods were available outside schools.

[Soil infiltration capacity under different vegetations in southern Ningxia Loess hilly region].

Science.gov (United States)

Yang, Yong-Hui; Zhao, Shi-Wei; Lei, Ting-Wu; Liu, Han

2008-05-01

A new apparatus for measuring the run off-on-out under simulated rainfall conditions was used to study the soil infiltration capacity under different rainfall intensities and vegetations in loess hilly region of southern Ningxia, with the relationships between soil water-stable aggregate content and soil stable infiltration rate under different vegetations analyzed. The results showed that the regression equations between rainfall duration and soil infiltration rate under different vegetations all followed y = a + be(-cx), with R2 ranged from 0.9678 to 0.9969. With the increase of rainfall intensity, the soil stable infiltration rate on slope cropland decreased, while that on Medicago lupulina land, natural grassland, and Caragana korshinskii land increased. Under the rainfall intensity of 20 mm h(-1), the rainfall infiltration translation rate (RITR) was decreased in the order of M. lupulina land > slope cropland > natural grassland > C. korshinskii land; while under the rainfall intensity of 40 mm h(-1) and 56 mm h(-1), the RITR was in the sequence of M. lupulina land > natural grassland > slope cropland > C. korshinskii land, and decreased with increasing rainfall intensity. After the reversion of cropland to grassland and forest land, and with the increase of re-vegetation, the amount of >0.25 mm soil aggregates increased, and soil infiltration capacity improved. The revegetation in study area effectively improved soil structure and soil infiltration capacity, and enhanced the utilization potential of rainfall on slope.

Kin competition within groups: the offspring depreciation hypothesis.

Science.gov (United States)

Ridley, J; Sutherland, W J

2002-12-22

Where relatives compete for the same resources (kin competition) and each obtains an equal share, this can favour the evolution of elevated dispersal rates, such that most resource competition is among non-relatives. We show that this effect evaporates as among-sibling dominance increases to the point where the allocation of resources is maximally unequal. We restore a kin-competition effect on emigration rates from dominance-ranked family groups by showing that where siblings form queues to inherit the breeding positions, the length of the queue affects the fitness of all individuals by depreciating the rank of subsequent offspring. Incorporating this 'offspring depreciation' effect decreases optimal queue lengths, increases dispersal rates and explains the otherwise paradoxical use of sinks by cooperatively breeding birds in stable environments. The offspring depreciation effect also favours the evolution of small, but consistent, clutch sizes and high reproductive skew, but constrains the evolution of alloparenting.

Competition in the Dutch hospital sector: an analysis of health care volume and cost.

Science.gov (United States)

Krabbe-Alkemade, Y J F M; Groot, T L C M; Lindeboom, M

2017-03-01

This paper evaluates the impact of market competition on health care volume and cost. At the start of 2005, the financing system of Dutch hospitals started to be gradually changed from a closed-end budgeting system to a non-regulated price competitive prospective reimbursement system. The gradual implementation of price competition is a 'natural experiment' that provides a unique opportunity to analyze the effects of market competition on hospital behavior. We have access to a unique database, which contains hospital discharge data of diagnosis treatment combinations (DBCs) of individual patients, including detailed care activities. Difference-in-difference estimates show that the implementation of market-based competition leads to relatively lower total costs, production volume and number of activities overall. Difference-in-difference estimates on treatment level show that the average costs for outpatient DBCs decreased due to a decrease in the number of activities per DBC. The introduction of market competition led to an increase of average costs of inpatient DBCs. Since both volume and number of activities have not changed significantly, we conclude that the cost increase is likely the result of more expensive activities. A possible explanation for our finding is that hospitals look for possible efficiency improvements in predominantly outpatient care products that are relatively straightforward, using easily analyzable technologies. The effects of competition on average cost and the relative shares of inpatient and outpatient treatments on specialty level are significant but contrary for cardiology and orthopedics, suggesting that specialties react differently to competitive incentives.

The effects of hospital competition on inpatient quality of care.

Science.gov (United States)

Mutter, Ryan L; Wong, Herbert S; Goldfarb, Marsha G

2008-01-01

Existing empirical studies have produced inconclusive, and sometimes contradictory, findings on the effects of hospital competition on inpatient quality of care. These inconsistencies may be due to the use of different methodologies, hospital competition measures, and hospital quality measures. This paper applies the Quality Indicator software from the Agency for Healthcare Research and Quality to the 1997 Healthcare Cost and Utilization Project State Inpatient Databases to create three versions (i.e., observed, risk-adjusted, and "smoothed") of 38 distinct measures of inpatient quality. The relationship between 12 different hospital competition measures and these quality measures are assessed, using ordinary least squares, two-step efficient generalized method of moments, and negative binomial regression techniques. We find that across estimation strategies, hospital competition has an impact on a number of hospital quality measures. However, the effect is not unidirectional: some indicators show improvements in hospital quality with greater levels of competition, some show decreases in hospital quality, and others are unaffected. We provide hypotheses based on emerging areas of research that could explain these findings, but inconsistencies remain.

Competition

NARCIS (Netherlands)

Bridoux, F.; Vodosek, M.; Den Hartog, D.N.; McNett, J.M.

2014-01-01

Competition traditionally refers to the actions that firms take in a product market to outperform rivals in attracting customers and generating revenues. Yet, competition extends beyond product markets to other arenas such as factor markets, where firms compete for resources, and the political

Relationships between aquatic vegetation and water turbidity: A field survey across seasons and spatial scales

OpenAIRE

Austin, ?sa N.; Hansen, Joakim P.; Donadi, Serena; Ekl?f, Johan S.

2017-01-01

Field surveys often show that high water turbidity limits cover of aquatic vegetation, while many small-scale experiments show that vegetation can reduce turbidity by decreasing water flow, stabilizing sediments, and competing with phytoplankton for nutrients. Here we bridged these two views by exploring the direction and strength of causal relationships between aquatic vegetation and turbidity across seasons (spring and late summer) and spatial scales (local and regional), using causal model...

Green Infrastructure Increases Biogeochemical Responsiveness, Vegetation Growth and Decreases Runoff in a Semi-Arid City, Tucson, AZ, USA

Science.gov (United States)

Meixner, T.; Papuga, S. A.; Luketich, A. M.; Rockhill, T.; Gallo, E. L.; Anderson, J.; Salgado, L.; Pope, K.; Gupta, N.; Korgaonkar, Y.; Guertin, D. P.

2017-12-01

Green Infrastructure (GI) is often viewed as a mechanism to minimize the effects of urbanization on hydrology, water quality, and other ecosystem services (including the urban heat island). Quantifying the effects of GI requires field measurements of the dimensions of biogeochemical, ecosystem, and hydrologic function that we expect GI to impact. Here we investigated the effect of GI features in Tucson, Arizona which has a low intensity winter precipitation regime and a high intensity summer regime. We focused on understanding the effect of GI on soil hydraulic and biogeochemical properties as well as the effect on vegetation and canopy temperature. Our results demonstrate profound changes in biogeochemical and hydrologic properties and vegetation growth between GI systems and nearby control sites. In terms of hydrologic properties GI soils had increased water holding capacity and hydraulic conductivity. GI soils also have higher total carbon, total nitrogen, and organic matter in general than control soils. Furthermore, we tested the sampled soils (control and GI) for differences in biogeochemical response upon wetting. GI soils had larger respiration responses indicating greater biogeochemical activity overall. Long-term Lidar surveys were used to investigate the differential canopy growth of GI systems versus control sites. The results of this analysis indicate that while a significant amount of time is needed to observe differences in canopy growth GI features due increase tree size and thus likely impact street scale ambient temperatures. Additionally monitoring of transpiration, soil moisture, and canopy temperature demonstrates that GI features increase vegetation growth and transpiration and reduce canopy temperatures. These biogeochemical and ecohydrologic results indicate that GI can increase the biogeochemical processing of soils and increase tree growth and thus reduce urban ambient temperatures.

Spatial Modeling of Urban Vegetation and Land Surface Temperature: A Case Study of Beijing

Directory of Open Access Journals (Sweden)

Chudong Huang

2015-07-01

Full Text Available The coupling relationship between urban vegetation and land surface temperature (LST has been heatedly debated in a variety of environmental studies. This paper studies the urban vegetation information and LST by utilizing a series of remote sensing imagery covering the period from 1990 to 2007. Their coupling relationship is analyzed, in order to provide the basis for ecological planning and environment protection. The results show that the normalized difference vegetation index (NDVI, urban vegetation abundance (UVA and urban forest abundance (UFA are negatively correlated with LST, which means that both urban vegetation and urban forest are capable in decreasing LST. The apparent influence of urban vegetation and urban forest on LST varies with the spatial resolution of the imagery, and peaks at the resolutions ranging from 90 m to 120 m.

EnviroAtlas - Portland, ME - 51m Riparian Buffer Vegetated Cover

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

EnviroAtlas - Portland, OR - 15m Riparian Buffer Vegetated Cover

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

EnviroAtlas - Phoenix, AZ - 51m Riparian Buffer Vegetated Cover

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

EnviroAtlas - Durham, NC - 51m Riparian Buffer Vegetated Cover

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

EnviroAtlas - Woodbine, IA - 15m Riparian Buffer Vegetated Cover

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

Vegetation mapping of the Mond Protected Area of Bushehr Province (south-west Iran).

Science.gov (United States)

Mehrabian, Ahmadreza; Naqinezhad, Alireza; Mahiny, Abdolrassoul Salman; Mostafavi, Hossein; Liaghati, Homan; Kouchekzadeh, Mohsen

2009-03-01

Arid regions of the world occupy up to 35% of the earth's surface, the basis of various definitions of climatic conditions, vegetation types or potential for food production. Due to their high ecological value, monitoring of arid regions is necessary and modern vegetation studies can help in the conservation and management of these areas. The use of remote sensing for mapping of desert vegetation is difficult due to mixing of the spectral reflectance of bright desert soils with the weak spectral response of sparse vegetation. We studied the vegetation types in the semiarid to arid region of Mond Protected Area, south-west Iran, based on unsupervised classification of the Spot XS bands and then produced updated maps. Sixteen map units covering 12 vegetation types were recognized in the area based on both field works and satellite mapping. Halocnemum strobilaceum and Suaeda fruticosa vegetation types were the dominant types and Ephedra foliata, Salicornia europaea-Suaeda heterophylla vegetation types were the smallest. Vegetation coverage decreased sharply with the increase in salinity towards the coastal areas of the Persian Gulf. The highest vegetation coverage belonged to the riparian vegetation along the Mond River, which represents the northern boundary of the protected area. The location of vegetation types was studied on the separate soil and habitat diversity maps of the study area, which helped in final refinements of the vegetation map produced.

Competition in Japan

OpenAIRE

Michael E. Porter; Mariko Sakakibara

2004-01-01

This article examines competition in Japan and its link to postwar economic prosperity. While Japan's industrial structure and competition policy seem to indicate that competition in Japan has been less intense, the empirical evidence does not support this conclusion. The sectors in which competition was restricted prove to be those where Japan was not internationally successful. In the internationally successful sectors, internal competition in Japan was invariably fierce. While the level of...

Competitive bidding in Medicare: who benefits from competition?

Science.gov (United States)

Song, Zirui; Landrum, Mary Beth; Chernew, Michael E

2012-09-01

To conduct the first empirical study of competitive bidding in Medicare. We analyzed 2006-2010 Medicare Advantage data from the Centers for Medicare and Medicaid Services using longitudinal models adjusted for market and plan characteristics. A $1 increase in Medicare's payment to health maintenance organization (HMO) plans led to a $0.49 (P service plans included, higher Medicare payments increased bids less ($0.33 per dollar), suggesting more competition among these latter plans. As a market-based alternative to cost control through administrative pricing, competitive bidding relies on private insurance plans proposing prices they are willing to accept for insuring a beneficiary. However, competition is imperfect in the Medicare bidding market. As much as half of every dollar in increased plan payment went to higher bids rather than to beneficiaries. While having more insurers in a market lowered bids, the design of any bidding system for Medicare should recognize this shortcoming of competition.

Opposing Responses of Bird Functional Diversity to Vegetation Structural Diversity in Wet and Dry Forest.

Directory of Open Access Journals (Sweden)

Holly Sitters

Full Text Available Disturbance regimes are changing worldwide, and the consequences for ecosystem function and resilience are largely unknown. Functional diversity (FD provides a surrogate measure of ecosystem function by capturing the range, abundance and distribution of trait values in a community. Enhanced understanding of the responses of FD to measures of vegetation structure at landscape scales is needed to guide conservation management. To address this knowledge gap, we used a whole-of-landscape sampling approach to examine relationships between bird FD, vegetation diversity and time since fire. We surveyed birds and measured vegetation at 36 landscape sampling units in dry and wet forest in southeast Australia during 2010 and 2011. Four uncorrelated indices of bird FD (richness, evenness, divergence and dispersion were derived from six bird traits, and we investigated responses of these indices and species richness to both vertical and horizontal vegetation diversity using linear mixed models. We also considered the extent to which the mean and diversity of time since fire were related to vegetation diversity. Results showed opposing responses of FD to vegetation diversity in dry and wet forest. In dry forest, where fire is frequent, species richness and two FD indices (richness and dispersion were positively related to vertical vegetation diversity, consistent with theory relating to environmental variation and coexistence. However, in wet forest subject to infrequent fire, the same three response variables were negatively associated with vertical diversity. We suggest that competitive dominance by species results in lower FD as vegetation diversity increases in wet forest. The responses of functional evenness were opposite to those of species richness, functional richness and dispersion in both forest types, highlighting the value of examining multiple FD metrics at management-relevant scales. The mean and diversity of time since fire were uncorrelated

Opposing Responses of Bird Functional Diversity to Vegetation Structural Diversity in Wet and Dry Forest.

Science.gov (United States)

Sitters, Holly; York, Alan; Swan, Matthew; Christie, Fiona; Di Stefano, Julian

2016-01-01

Disturbance regimes are changing worldwide, and the consequences for ecosystem function and resilience are largely unknown. Functional diversity (FD) provides a surrogate measure of ecosystem function by capturing the range, abundance and distribution of trait values in a community. Enhanced understanding of the responses of FD to measures of vegetation structure at landscape scales is needed to guide conservation management. To address this knowledge gap, we used a whole-of-landscape sampling approach to examine relationships between bird FD, vegetation diversity and time since fire. We surveyed birds and measured vegetation at 36 landscape sampling units in dry and wet forest in southeast Australia during 2010 and 2011. Four uncorrelated indices of bird FD (richness, evenness, divergence and dispersion) were derived from six bird traits, and we investigated responses of these indices and species richness to both vertical and horizontal vegetation diversity using linear mixed models. We also considered the extent to which the mean and diversity of time since fire were related to vegetation diversity. Results showed opposing responses of FD to vegetation diversity in dry and wet forest. In dry forest, where fire is frequent, species richness and two FD indices (richness and dispersion) were positively related to vertical vegetation diversity, consistent with theory relating to environmental variation and coexistence. However, in wet forest subject to infrequent fire, the same three response variables were negatively associated with vertical diversity. We suggest that competitive dominance by species results in lower FD as vegetation diversity increases in wet forest. The responses of functional evenness were opposite to those of species richness, functional richness and dispersion in both forest types, highlighting the value of examining multiple FD metrics at management-relevant scales. The mean and diversity of time since fire were uncorrelated with vegetation

Competitive Priorities and Competitive Advantage in Jordanian Manufacturing

OpenAIRE

Awwad, Abdulkareem S.; Al Khattab, Adel A.; Anchor, J.R

2013-01-01

The purpose of this research was to explore and predict the relationship between the competitive priorities (quality, cost, flexibility and delivery) and the competitive advantage of firms in the Jordanian Industrial Sector. A population of 88 Jordanian manufacturing firms, registered on the Amman Stock Exchange, was targeted using a cross-sectional survey employing a questionnaire method of data collection. The results of the data analysis indicate a significant relationship between competit...

The New Supply Chain: Implications to the Fresh Fruits and Vegetables Sector in Malaysia

OpenAIRE

Fatimah Mohamed Arshad

2013-01-01

This paper traces the growth of the new retail formats such as hypermarkets, departmental stores and supermarkets and its implications to the fruits and vegetables sector in Malaysia in particular to the small producers. The structural differences between the new supply chain and conventional marketing are compared. Some measures of concentration are provided to indicate the degree of competition in the retail sector. Within less than a decade, the new super retailers were able to capture...

SPP will decrease price of transport

International Nuclear Information System (INIS)

Janoska, J.

2003-01-01

Starting next year gas utility Slovensky plynarensky priemysel, a.s., Bratislava (SPP) will decrease the fees for transport of gas to its client from third parties. This decision should have a positive effect mainly on large industrial customers. The fact that SPP decided not to apply the approved ruling to its full extent was the result of negotiations with the regulator and the Ministry of Economy. SPP is not afraid it might lose customers. This decision only gives them a competitive advantage. (Author)

Ecogeomorphology of Sand Dunes Shaped by Vegetation

Science.gov (United States)

Tsoar, H.

2014-12-01

Two dune types associated with vegetation are known: Parabolic and Vegetated Linear Dunes (VLDs), the latters are the dominant dune type in the world deserts. Parabolic dunes are formed in humid, sub-humid and semi-arid environments (rather than arid) where vegetation is nearby. VLDs are known today in semiarid and arid lands where the average yearly rainfall is ≥100 mm, enough to support sparse cover of vegetation. These two dune types are formed by unidirectional winds although they demonstrate a different form and have a distinct dynamics. Conceptual and mathematical models of dunes mobility and stability, based on three control parameters: wind power (DP), average annual precipitation (p), and the human impact parameter (μ) show that where human impact is negligible the effect of wind power (DP) on vegetative cover is substantial. The average yearly rainfall of 60-80 mm is the threshold of annual average rainfall for vegetation growth on dune sand. The model is shown to follow a hysteresis path, which explains the bistability of active and stabilized dunes under the same climatic conditions with respect to wind power. We have discerned formation of parabolic dunes from barchans and transverse dunes in the coastal plain of Israel where a decrease in human activity during the second half of the 20th century caused establishment of vegetation on the crest of the dunes, a process that changed the dynamics of these barchans and transverse dunes and led to a change in the shape of the windward slope from convex to concave. These dunes gradually became parabolic. It seems that VLDs in Australia or the Kalahari have always been vegetated to some degree, though the shrubs were sparser in colder periods when the aeolian erosion was sizeable. Those ancient conditions are characterized by higher wind power and lower rainfall that can reduce, but not completely destroy, the vegetation cover, leading to the formation of lee (shadow) dunes behind each shrub. Formation of

The competition of Linum with Camelina for minerals. 3

International Nuclear Information System (INIS)

Kranz, E.; Jacob, F.

1978-01-01

The competitive condition in the sulphate uptake of flax (Linum usitatissimum L.) and Camelina sativa (L.) Crantz was influenced by the herbicides MCPA, fenuron, alachlor and chloropham. Those herbicides (10 -4 M in each case) inhibited the uptake of sulphate of the plants. 12 h after exposing the plants in a solution deficient in sulphate flax plants in mixed culture took up less sulphate under the influence of MCPA, fenuron and chlorpropham. Camelina plants, however, also in mixed culture, with the exception of the MCPA variant, took up more of those ions than in monoculture. Under these conditions no essential change of the competitive conditions was found. In mixed culture, however, the sulphate uptake of Camelina plants - in percent of the untreated variant - was lower than in monoculture. In contrast to the untreated variants the sulphate uptake of Camelina plants decreased under the influence of alachlor in mixture, whereas there was no decrease found with Linum plants, both compared with the monoculture controls. Under influence of chlorpropham (10 -4 M) with an increased level of sulphate no essential decrease of sulphate uptake of Linum plants in mixture was found. With Camelina plants, however, a decrease of uptake in mixed culture was examined, both compared again with uptake in monoculture. (author)

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.

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.

Experimental and theoretical study of microalgal competition in laboratory and natural ecosystems

Science.gov (United States)

Pisman, T. I.; Somova, L. A.

An important aspect of studying mixed cultures of microalgae is the artificial ecosystems containing algal culture as a regeneration link and a source of vegetable substances. The peculiarities of studying the stability of microalgae mixed cultures in the laboratory and natural environment have been considered in the work. The role of factors most essentially affecting the species structure of phytoplankton community (temperature factor, light intensity, pH environments, elements of mineral nutrition, algal metabolites, predation and fluctuation of environmental conditions) has been displayed. As a result of experimental and theoretical modelling of the microalgae Chlorella vulgaris and Scenedesmus quadricauda competition under limitation on nitrogen, the impossibility of their co-existence has been revealed. Under these conditions Chl. vulgaris turned out to be less competitive than Sc. quadricauda. The influence of the ratio of biogenic elements concentration in the environment, which should be recognized as an independent regulatory factor limiting growth of populations in the community and, thus affecting its structure, has been analyzed.

The Literature Review of a New Form of Competitiveness Called City Competitiveness

Directory of Open Access Journals (Sweden)

Osman EROĞLU

2014-06-01

Full Text Available With globalization, the rapid development of information technologies and the rapid changes in the economic structure, the country’s borders at a time increasingly depreciate and the importance of city competitiveness reveals. Although it is an ongoing debate around the world whether cities compete with each other, city competitiveness is a new form of competitiveness. Cities compete with each other to increase their competitiveness. City competitiveness is defined as having better values compared to other cities. In this study, a new form of competitiveness called city competitiveness is examined.

Estimation of vegetation cover resilience from satellite time series

Directory of Open Access Journals (Sweden)

T. Simoniello

2008-07-01

Full Text Available Resilience is a fundamental concept for understanding vegetation as a dynamic component of the climate system. It expresses the ability of ecosystems to tolerate disturbances and to recover their initial state. Recovery times are basic parameters of the vegetation's response to forcing and, therefore, are essential for describing realistic vegetation within dynamical models. Healthy vegetation tends to rapidly recover from shock and to persist in growth and expansion. On the contrary, climatic and anthropic stress can reduce resilience thus favouring persistent decrease in vegetation activity.

In order to characterize resilience, we analyzed the time series 1982–2003 of 8 km GIMMS AVHRR-NDVI maps of the Italian territory. Persistence probability of negative and positive trends was estimated according to the vegetation cover class, altitude, and climate. Generally, mean recovery times from negative trends were shorter than those estimated for positive trends, as expected for vegetation of healthy status. Some signatures of inefficient resilience were found in high-level mountainous areas and in the Mediterranean sub-tropical ones. This analysis was refined by aggregating pixels according to phenology. This multitemporal clustering synthesized information on vegetation cover, climate, and orography rather well. The consequent persistence estimations confirmed and detailed hints obtained from the previous analyses. Under the same climatic regime, different vegetation resilience levels were found. In particular, within the Mediterranean sub-tropical climate, clustering was able to identify features with different persistence levels in areas that are liable to different levels of anthropic pressure. Moreover, it was capable of enhancing reduced vegetation resilience also in the southern areas under Warm Temperate sub-continental climate. The general consistency of the obtained results showed that, with the help of suited analysis

A review of mechanisms underlying anticarcinogenicity by brassica vegetables

NARCIS (Netherlands)

Verhoeven, D.T.H.; Verhagen, H.; Goldbohm, R.A.; Brandt, P.A. van den; Poppel, G. van

1997-01-01

The mechanisms by which brassica vegetables might decrease the risk of cancer are reviewed in this paper. Brassicas, including all types of cabbages, broccoli, cauliflower and Brussels sprouts, may be protective against cancer due to their relatively high glucosinolate content. Glucosinolates are

Timing effects of heat-stress on plant physiological characteristics and growth: a field study with prairie vegetation

Directory of Open Access Journals (Sweden)

Dan Wang

2016-11-01

Full Text Available More intense, more frequent, and longer heat-waves are expected in the future due to global warming, which could have dramatic agricultural, economic and ecological impacts. This field study examined how plant responded to heat-stress (HS treatment at different timing in naturally-occurring vegetation. HS treatment (5 days at 40.5 ºC were applied to 12 1m2 plots in restored prairie vegetation dominated by Andropogon gerardii (warm-season C4 grass and Solidago canadensis (warm-season C3 forb at different growing stages. During and after HS, air, canopy, and soil temperature were monitored; net CO2 assimilation (Pn, quantum yield of photosystem II (ФPSII, stomatal conductance (gs, and internal CO2 level (Ci of the dominant species were measured. One week after the last HS treatment, all plots were harvested and the biomass of above-ground tissue and flower weight of the two dominant species was determined. HS decreased physiological performance and growth for both species, with S. canadensis being affected more than A. gerardii, indicated by negative heat stress effect on both physiological and growth responses. There were significant timing effect of heat stress on the two species, with greater reductions in the photosynthesis and productivity occurred when heat stress was applied at later-growing season. The reduction in aboveground productivity in S. canadensis but not A. gerardii could have important implications for plant community structure by increasing the competitive advantage of A. gerardii in this grassland. The present experiment showed that heat stress, though ephemeral, may promote long-term effects on plant community structure, vegetation dynamics, biodiversity, and ecosystem functioning of terrestrial biomes when more frequent and severe heat stress occur in the future.

Vegetable oil based liquid nanocomposite dielectric

Directory of Open Access Journals (Sweden)

Leon Chetty

2013-01-01

Full Text Available Physically smaller dielectric materials would improve the optimisation of space for power systems. Development of nanotechnology provides an effective way to improve the performances of insulating oils used in power system applications. In this research study, we focused on the development of nanomodified vegetable oils to be used in power transformers. Higher conduction currents were observed in virgin linseed oil than in virgin castor oil. However, for both virgin linseed and virgin castor oil, the DC conduction current increased approximately linearly with the applied DC voltage. In nanomodified linseed oil, the characteristic curve showed two distinct regions: a linear region (at lower applied voltage and a saturation region (at slightly higher voltage. Conversely, in nanomodified castor oil, the characteristic curve showed three distinct regions: a linear region (at lower applied voltage, a saturation region (at intermediate applied voltage and an exponential growth region (at higher applied voltage. The nanomodified linseed oil exhibited a better dielectric performance than the nanomodified castor oil. Overall, the addition of nanodielectrics to vegetable oils decreased the dielectric performance of the vegetable oils. The results of this study contribute to the understanding of the pre-breakdown phenomenon in liquid nanocomposite dielectrics.

Monitoring temporal Vegetation changes in Lao tropical forests

International Nuclear Information System (INIS)

Phompila, Chittana; Lewis, Megan; Clarke, Kenneth; Ostendorf, Bertram

2014-01-01

Studies on changes in vegetation are essential for understanding the interaction between humans and the environment. These studies provide key information for land use assessment, terrestrial ecosystem monitoring, carbon flux modelling and impacts of global climate change. The primary purpose of this study was to detect temporal vegetation changes in tropical forests in the southern part of Lao PDR from 2001-2012. The study investigated the annual vegetation phenological response of dominant land cover types across the study area and relationships to seasonal precipitation and temperature. Improved understanding of intra-annual patterns of vegetation variation was useful to detect longer term changes in vegetation. The breaks for additive season and trend (BFAST) approach was implemented to detect changes in these land cover types throughout the 2001-2012 period. We used the enhanced vegetation index (EVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) (MOD13Q1 products) and monthly rainfall and temperature data obtained from the Meteorology and Hydrology Department, Ministry of Agriculture-Forestry, published by Lao National Statistical Centre in this research. EVI well documented the annual seasonal growth of vegetation and clearly distinguished the characteristic phenology of four different land use types; native forest, plantation, agriculture and mixed wooded/cleared area. Native forests maintained high EVI throughout the year, while plantations, wooded/cleared areas and agriculture showed greater inter-annual variation, with minimum EVI at the end of the dry season in April and maximum EVI in September-October, around two months after the wet season peak in rainfall. The BFAST analysis detected abrupt temporal changes in vegetation in the tropical forests, especially in a large conversion of mixed wooded/cleared area into plantation. Within the study area from 2001-2012 there has been an overall decreasing trend of vegetation cover for

Effects of competitive pressure on expert performance: underlying psychological, physiological, and kinematic mechanisms.

Science.gov (United States)

Cooke, Andrew; Kavussanu, Maria; McIntyre, David; Boardley, Ian D; Ring, Christopher

2011-08-01

Although it is well established that performance is influenced by competitive pressure, our understanding of the mechanisms which underlie the pressure-performance relationship is limited. The current experiment examined mediators of the relationship between competitive pressure and motor skill performance of experts. Psychological, physiological, and kinematic responses to three levels of competitive pressure were measured in 50 expert golfers, during a golf putting task. Elevated competitive pressure increased putting accuracy, anxiety, effort, and heart rate, but decreased grip force. Quadratic effects of pressure were noted for self-reported conscious processing and impact velocity. Mediation analyses revealed that effort and heart rate partially mediated improved performance. The findings indicate that competitive pressure elicits effects on expert performance through both psychological and physiological pathways. Copyright © 2011 Society for Psychophysiological Research.

The effect of temperature on growth and competition between Sphagnum species.

Science.gov (United States)

Breeuwer, Angela; Heijmans, Monique M P D; Robroek, Bjorn J M; Berendse, Frank

2008-05-01

Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4 degrees C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species.

The effect of temperature on growth and competition between Sphagnum species

Science.gov (United States)

Heijmans, Monique M. P. D.; Robroek, Bjorn J. M.; Berendse, Frank

2008-01-01

Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4°C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species. PMID:18283501

Vegetation pattern formation in a fog-dependent ecosystem.

Science.gov (United States)

Borthagaray, Ana I; Fuentes, Miguel A; Marquet, Pablo A

2010-07-07

Vegetation pattern formation is a striking characteristic of several water-limited ecosystems around the world. Typically, they have been described on runoff-based ecosystems emphasizing local interactions between water, biomass interception, growth and dispersal. Here, we show that this situation is by no means general, as banded patterns in vegetation can emerge in areas without rainfall and in plants without functional root (the Bromeliad Tillandsia landbeckii) and where fog is the principal source of moisture. We show that a simple model based on the advection of fog-water by wind and its interception by the vegetation can reproduce banded patterns which agree with empirical patterns observed in the Coastal Atacama Desert. Our model predicts how the parameters may affect the conditions to form the banded pattern, showing a transition from a uniform vegetated state, at high water input or terrain slope to a desert state throughout intermediate banded states. Moreover, the model predicts that the pattern wavelength is a decreasing non-linear function of fog-water input and slope, and an increasing function of plant loss and fog-water flow speed. Finally, we show that the vegetation density is increased by the formation of the regular pattern compared to the density expected by the spatially homogeneous model emphasizing the importance of self-organization in arid ecosystems. (c) 2010 Elsevier Ltd. All rights reserved.

Productive and Unproductive Competition

DEFF Research Database (Denmark)

Guerra, Alice; Luppi, Barbara; Parisi, Francesco

Conventional theories of competition classify contests as being either “productive,” when the competitive efforts generate a surplus for society, or “unproductive,” when competition generates no social surplus and merely distributes already existing resources. These two discrete categories of com...... and socially optimal levels of competition in the full range of intermediate cases, as well as in the extremum cases of destructive and super-productive competition.......Conventional theories of competition classify contests as being either “productive,” when the competitive efforts generate a surplus for society, or “unproductive,” when competition generates no social surplus and merely distributes already existing resources. These two discrete categories...... of competition create a division of real-world situations into analytical categories that fails to recognize the entire spectrum of competitive activities. Taking the existing models of productive and unproductive competition as benchmark idealizations, this paper explores the relationship between the privately...

Spatial variation in atmospheric nitrogen deposition on low canopy vegetation

International Nuclear Information System (INIS)

Verhagen, Rene; Diggelen, Rudy van

2006-01-01

Current knowledge about the spatial variation of atmospheric nitrogen deposition on a local scale is limited, especially for vegetation with a low canopy. We measured nitrogen deposition on artificial vegetation at variable distances of local nitrogen emitting sources in three nature reserves in the Netherlands, differing in the intensity of agricultural practices in the surroundings. In the nature reserve located in the most intensive agricultural region nitrogen deposition decreased with increasing distance to the local farms, until at a distance of 1500 m from the local nitrogen emitting sources the background level of 15 kg N ha -1 yr -1 was reached. No such trend was observed in the other two reserves. Interception was considerably lower than in woodlands and hence affected areas were larger. The results are discussed in relation to the prospects for the conservation or restoration of endangered vegetation types of nutrient-poor soil conditions. - Areas with low canopy vegetation are affected over much larger distances by nitrogen deposition than woodlands

Metabolic evaluation of Crioulo horses participating in competitions of 750 km

Directory of Open Access Journals (Sweden)

Lorena Alvariza Amaral

2013-12-01

Full Text Available The Crioulo breed of horses performs in one of the most physically demanding equestrian competitions, the Marcha de Resistência, which is a contest in which the horses run 750 km in 15 days. The study's aim was to characterize the metabolic responses during this period. We evaluated eleven Crioulo horses in the competition, specifically, two males and nine females. Blood samples were collected 24 hours before the contest and on the 4th, 9th, 11th, 14th and 15th days of competition. We evaluated CK, AST, LDH, glucose, lactate, urea, creatinine, sodium, potassium, chloride, magnesium, total calcium, ionized calcium, total protein, hematocrit and the white blood cell count. At the end of the competition, the mean values of serum AST were 1151±358 IU/ L the mean LDH values were 7418±1695 IU/L and CK was 13,867±3998UI /L. There was a significant increase in urea, creatinine and lactate (p<0.0001. A decrease in the mean values of chloride, sodium, potassium, and total and ionized calcium was observed (p≤0.0002. An evaluation of the total leukocytes and segmented neutrophils (p≤0.0002 revealed their increased values, and decreased values were observed for hematocrit, plasma protein and total lymphocytes (p≤0.0003. The values of glucose, on average, remained constant. Based on these data, we conclude that the Marcha de Resistência competition necessitated a high muscular demand and the depletion of energy and electrolytes, suggesting an inflammatory process in the animals evaluated.

Effect of playing violent video games cooperatively or competitively on subsequent cooperative behavior.

Science.gov (United States)

Ewoldsen, David R; Eno, Cassie A; Okdie, Bradley M; Velez, John A; Guadagno, Rosanna E; DeCoster, Jamie

2012-05-01

Research on video games has yielded consistent findings that violent video games increase aggression and decrease prosocial behavior. However, these studies typically examined single-player games. Of interest is the effect of cooperative play in a violent video game on subsequent cooperative or competitive behavior. Participants played Halo II (a first-person shooter game) cooperatively or competitively and then completed a modified prisoner's dilemma task to assess competitive and cooperative behavior. Compared with the competitive play conditions, players in the cooperative condition engaged in more tit-for-tat behaviors-a pattern of behavior that typically precedes cooperative behavior. The social context of game play influenced subsequent behavior more than the content of the game that was played.

Stand Dynamics and Plant Associates of Loblolly Pine Plantations to Midrotation after Early Intensive Vegetation Management-A Southeastern United States Regional Study

Science.gov (United States)

James H. Miller; Bruce R. Zutter; Ray A. Newbold; M. Boyd Edwards; Shepard M. Zedaker

2003-01-01

Increasingly, pine plantations worldwide are grown using early control of woodv and/or herbaceous vegetation. Assuredsustainablepractices require long-term data on pine plantation development detailing patterns and processes to understand both crop-competition dynamics and the role of stand participants in providing multiple attributes such as biodiversity conservation...

Dynamic aggregation evolution of competitive societies of cooperative and noncooperative agents

International Nuclear Information System (INIS)

Lin Zhen-Quan; Ye Gao-Xiang

2013-01-01

We propose an evolution model of cooperative agent and noncooperative agent aggregates to investigate the dynamic evolution behaviors of the system and the effects of the competing microscopic reactions on the dynamic evolution. In this model, each cooperative agent and noncooperative agent are endowed with integer values of cooperative spirits and noncooperative spirits, respectively. The cooperative spirits of a cooperative agent aggregate and the noncooperative spirits of a noncooperative agent aggregate change via four competing microscopic reaction schemes: the win-win reaction between two cooperative agents, the lose-lose reaction between two noncooperative agents, the win-lose reaction between a cooperative agent and a noncooperative agent (equivalent to the migration of spirits from cooperative agents to noncooperative agents), and the cooperative agent catalyzed decline of noncooperative spirits. Based on the generalized Smoluchowski's rate equation approach, we investigate the dynamic evolution behaviors such as the total cooperative spirits of all cooperative agents and the total noncooperative spirits of all noncooperative agents. The effects of the three main groups of competition on the dynamic evolution are revealed. These include: (i) the competition between the lose-lose reaction and the win-lose reaction, which gives rise to respectively the decrease and increase in the noncooperative agent spirits; (ii) the competition between the win-win reaction and the win-lose reaction, which gives rise to respectively the increase and decrease in the cooperative agent spirits; (iii) the competition between the win-lose reaction and the catalyzed-decline reaction, which gives rise to respectively the increase and decrease in the noncooperative agent spirits. (interdisciplinary physics and related areas of science and technology)

Mixing, entropy and competition

International Nuclear Information System (INIS)

Klimenko, A Y

2012-01-01

Non-traditional thermodynamics, applied to random behaviour associated with turbulence, mixing and competition, is reviewed and analysed. Competitive mixing represents a general framework for the study of generic properties of competitive systems and can be used to model a wide class of non-equilibrium phenomena ranging from turbulent premixed flames and invasion waves to complex competitive systems. We demonstrate consistency of the general principles of competition with thermodynamic description, review and analyse the related entropy concepts and introduce the corresponding competitive H-theorem. A competitive system can be characterized by a thermodynamic quantity—competitive potential—which determines the likely direction of evolution of the system. Contested resources tend to move between systems from lower to higher values of the competitive potential. There is, however, an important difference between conventional thermodynamics and competitive thermodynamics. While conventional thermodynamics is constrained by its zeroth law and is fundamentally transitive, the transitivity of competitive thermodynamics depends on the transitivity of the competition rules. Intransitivities are common in the real world and are responsible for complex behaviour in competitive systems. This work follows ideas and methods that have originated from the analysis of turbulent combustion, but reviews a much broader scope of issues linked to mixing and competition, including thermodynamic characterization of complex competitive systems with self-organization. The approach presented here is interdisciplinary and is addressed to the general educated readers, whereas the mathematical details can be found in the appendices. (comment)

Competitiveness of the match for interventional radiology and neuroradiology fellowships.

Science.gov (United States)

Chen, Jim Y; Agarwal, Vikas; Orons, Philip D

2014-11-01

Overall resident interest in certain subspecialties changes with time. We sought to investigate the latest 6-year trend in interventional radiology (IR) and neuroradiology fellowship applications and how it has affected competitiveness in obtaining a position. We analyzed statistics published by the National Resident Matching Program in Results and Data: Specialties Matching Service from 2008 to 2013. From these data, we calculated the positions per IR applicant (PPIRA) and positions per neuroradiology applicant (PPNRA) for each year. The number of positions per applicant is one way to assess specialty competitiveness on a supply-and-demand basis. A lower PPIRA or PPNRA indicates a more competitive year. PPIRA has decreased every year, from 1.71 to the present 0.84, and contributed to 52 applicants being unmatched in 2013, up from 9 in 2008. Accordingly, the number of unfilled positions has decreased from 86 in 2008 to 8 in 2013. PPNRA waxed and waned from 2008 to 2010 but stabilized at around 1.15 thereafter. The number of unfilled positions has never dropped below 46. The number of unmatched applicants was consistently in the teens, except in 2011, when it increased to 23. Interest in IR fellowship has increased significantly over the past 6 years, whereas interest in neuroradiology fellowships has plateaued. IR fellowships have become increasingly competitive, leading to many unmatched residents. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Floodplain rehabilitation in North Cameroon: impact on vegetation dynamics

NARCIS (Netherlands)

Scholte, P.; Kirda, P.; Adam, S.; Kadiri, B.

2000-01-01

Since the construction in 1979 of a dam in the Logone floodplain in the Sahelo-Sudanian zone of Cameroon, annual inundations have decreased, reducing perennial vegetation as important grazing source for nomadic herds and wildlife during the dry season. Presently, possibilities exist to release

Competitive interaction in plant populations exposed to supplementary ultraviolet-B radiation

International Nuclear Information System (INIS)

Fox, F.M.; Caldwell, M.M.; Utah State Univ., Logan

1978-01-01

Changes in plant growth and competitive balance between pairs of competing species were documented as a result of supplementary ultraviolet-B radiation (principally in the 290-315 nm waveband) under field conditions. This component of the terrestrial solar spectrum would be intensified if the atmospheric ozone layer were reduced. A method for calculating and statistically analyzing relative crowding coefficients was developed and used to evaluate the competitive status of the species pairs sown in a modified replacement series. The effect of the supplementary UV-B irradiance was generally detrimental to plant growth, and was reflected in decreased leaf area, biomass, height and density as well as changes competitive balance for various species. For some species, interspecific competition apparently accentuated the effect of the UV-B radiation, while more intense intraspecific competition may have had the same effect for other species. A few species when grown in a situation of more severe mutual interspecific competition exhibited enhanced growth under the UV-B radiation treatment. This, however, was usually associated with a detrimental effect of the radiation, on its competitor and thus was likely the result of its improved competitive circumstance rather than a benefical physiological effect of the radiation. (orig.) [de

Analysis of consumption frequencies of vegetables and fruits in Korean adolescents based on Korea youth risk behavior web-based survey (2006, 2011).

Science.gov (United States)

Kim, Yangsuk; Kwon, Yong-Suk; Park, Young-Hee; Choe, Jeong-Sook; Lee, Jin-Young

2015-08-01

This study analyzed factors affecting consumption frequencies of vegetables and fruits in Korean adolescents. Consumption frequencies of vegetables and fruits, general characteristics, meal, health, and other variables were analyzed for a total of 147,047 adolescents who participated in the KYRBWS (Korea Youth Risk Behavior Web-based Survey) conducted in 2006 and 2011 by the Korea Centers for Disease Control and Prevention. Consumption frequencies of vegetables and fruits more than once a day significantly decreased in 2011 compared to 2006 based on Chi-square test conducted for every factor employed in the study. Analysis of factors showed that consumption frequencies of vegetables and fruits were reduced in both study years as subjective income decreased, whereas intake frequencies increased with mother's education level and reduction of adolescent stress level. In general, consumption frequencies of vegetables and fruits decreased in 2011 compared to those in 2006. Thus, future research needs to improve dietary guidelines for nutrition education in order for students to recognize the importance of food consumption and necessity of increasing daily serving sizes of vegetables and fruits for their balanced consumption.

Vegetation Carbon Storage, Spatial Patterns and Response to Altitude in Lancang River Basin, Southwest China

Directory of Open Access Journals (Sweden)

Long Chen

2016-01-01

Full Text Available Vegetation plays a very important role of carbon (C sinks in the global C cycle. With its complex terrain and diverse vegetation types, the Lancang River Basin (LRB of southwest China has huge C storage capacity. Therefore, understanding the spatial variations and controlling mechanisms of vegetation C storage is important to understand the regional C cycle. In this study, data from a forest inventory and field plots were used to estimate and map vegetation C storage distribution in the LRB, to qualify the quantitative relationships between vegetation C density and altitude at sublot and township scale, and a linear model or polynomial model was used to identify the relationship between C density and altitude at two spatial scales and two statistical scales. The results showed that a total of 300.32 Tg C was stored in the LRB, an important C sink in China. The majority of C storage was contributed by forests, notably oaks. The vegetation C storage exhibited nonlinear variation with latitudinal gradients. Altitude had tremendous influences on spatial patterns of vegetation C storage of three geomorphological types in the LRB. C storage decreased with increasing altitude at both town and sublot scales in the flat river valley (FRV region and the mid-low mountains gorge (MMG region, and first increased then decreased in the alpine gorge (AG region. This revealed that, in southwest China, altitude changes the latitudinal patterns of vegetation C storage; especially in the AG area, C density in the mid-altitude (3100 m area was higher than that of adjacent areas.

NEW GREENHOUSE TECHNOLOGIES FOR VEGETABLE PRODUCTION

Directory of Open Access Journals (Sweden)

S. M. Sirota

2016-01-01

Full Text Available First decade of XXI century is characterized by significant augmentation in vegetable world’s production. Average annual vegetable production has been 346 million tons, and it has exceeded the average annual potato production (318 million tons. It has occurred due to the use of up-to-date technologies for vegetable production and, particularly, in greenhouses. In Russian Federation, the total production of vegetables was 5 275.6 thousand tons in 2015 that was 13.3% more than in 2014. But the total vegetable production in greenhouses was only 722.8 thousand tons, that was 0.7% less than in 2014 (728.1 thousand tons. It can be explained that the old technologies have been used for many greenhouses around Russia. Up-to-date technologies for greenhouses are described in the article. Small-volume hydroponics. Plants are grown in mineral wadding, packed up in the special chutes. Mineral nutrition and water are supplied through special pipe with many branch pipes toward each plant. Advantage: pH and nutrition are maintained, consumption of water and mineral nutrition are optimized, and that improves plants grow control. Expenditures of labor decreased, quality of fruit became better and the yield increased significantly by 45-50 kg/m2 comparing with growing on the soil (25-30 kg/m2. Hydroponics with flowing water (salad production lines. Conveyor for salad and vegetable growing on horizontal moving chutes with flowing water and nutrition was developed. Advantage: high level of automation and mechanization of all processes of growing increased the effectiveness of the use of greenhouse areas (we can place 30% plants more at the same area. Seedling production lines. Production lines for seedlings enable to grow vegetables and leafy vegetables on stationary benches, being furnished with periodical nutrition and water supply at times. Advantage: 700 seedlings additionally on each m2 a year. Future technologies are

Dancing in the Dark: Competition over the "Meaning of Competition"

OpenAIRE

Metcalfe John Stanley

2009-01-01

Competing concepts of competition provide a sharp divide between theories of economic order and theories of economic transformation. The shift from competition as a state of affairs and competition as a creative process provides the divergence of perspective that is the topic of this paper. We link the Smith Marshall approach of rivalry and open competition to the more modern evolutionary view based on variation cum selection perspectives on innovation and the adaptive role of market processe...

Competitive intelligence: An instrument to enhance South Africa’s competitiveness

Directory of Open Access Journals (Sweden)

Wilma Viviers

2014-10-01

Full Text Available The case for Competitive Intelligence (CI as an instrument that can enhance the competitiveness of South African companies and South Africa as a country is strong. Various global competitive rankings measurements have indicated over a number of years the areas in which competitiveness is lacking. Moreover, these rankings have indicated that South Africa has failed to improve its position year on year. The fact that the world is becoming increasingly competitive for South African entities is undisputed. Coupled with a fluctuating exchange rate and the country’s geographical proximity, this poses unique challenges facing South African managers who have to deal with various regulations and legislative matters. In order to create and sustain an effective knowledge economy and to enhance global competitiveness, South Africa however has to put appropriate strategies/measures in place to stimulate, encourage and grow knowledge practices. Competitive Intelligence (CI as a means of making more sense of the competitive business environment and to identify opportunities and risks in time to act upon can be effectively used as a means to enhance competitiveness. Valuable lessons from successful CI practices in the business sector and government can be learnt from elsewhere in the world. CI should be investigated and adapted for South Africa’s business environment. It is therefore the aim of this article to first attempt to describe the role of CI in enhancing competitiveness, specifically in South Africa and secondly, to stimulate thought on how to secure momentum in enhancing CI as an academic field by developing relevant CI courses as well as demonstrating the value of CI to companies in South Africa through research and collaboration between academics and the private and public sectors.

Concentration and Competition in the Banking Sector of Turkey

Directory of Open Access Journals (Sweden)

Iveta Řepková

2014-05-01

Full Text Available The paper estimates the competitive conditions and concentration in the Turkish banking industry during the period 2002-2010. The period starts after implementation of the comprehensive reform in the banking sector and lasts until culmination of the global financial crisis. The concentration ratio and the Herfindahl-Hirschman index are applied to measure level of concentration. We found the banking sector to be almost non-concentrated with exemption of deposit market where we revealed a slight concentration. However, there is a clear trend of increasing concentration at all segments of the Turkish banking sector over the analysed period. The Panzar-Rosse model is used for estimation of competitive conditions in the banking market. Specifically, we use a panel with data for most of the Turkish banks to estimate the H statistics. We concluded that the Turkish banking sector can be characterized as an industry with monopolistic competition that closely approaches monopoly. The results imply that banks in Turkey do not operate in a competitive environment and enjoy monopoly rents. Moreover, we revealed decreasing level of competition during the entire period of estimation. Such a market structure can pose a threat for efficient intermediation of funds through the banking sector and promoting of economic growth.

Earlier vegetation green-up has reduced spring dust storms.

Science.gov (United States)

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-10-24

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = -0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world.

Caesium dynamics in the peats and associated vegetation of northern Greece and northern Scotland

International Nuclear Information System (INIS)

Heaton, B.; Mitchell, R.D.J.; Killham, K.; Veresoglou, D.S.

1990-01-01

Sequential analyses have shown that Chernobyl-derived caesium has been largely retained in Greek basin peats (highly cultivated, base-rich, sedge peats) and retained/cycled in Scottish upland peats (uncultivated, base-poor, blanket peats). To investigate the mechanisms of retention and cycling in the Scottish peat/vegetation system, a laboratory experiment was carried out involving 'microcosms' intact peat cores. Festuca ovina was grown from seed in the cores prior to nebuliser-application of simulated rain containing caesium-134. The major factors investigated were competitive ion exchange from ammonium (designed to simulate animal waste inputs), freeze-thaw activity, and cropping (designed to simulate upland grazing). The effects of these factors are discussed in relation to the physio-cochemical and biological properties of the peat and vegetation and to our observations of the movement of caesium in the field. (author)

Effect of irradiation on detection of bacteria in dehydrated vegetables with ATP bioluminescence assay

International Nuclear Information System (INIS)

Xiao Huan; Luo Shishi; Wang Zegang; Feng Min; Zhu Jiating; Chen Xiulan; Zhai Jianqing

2011-01-01

ATP bioluminescence intensity of 4 kinds of irradiated dehydrated vegetables was inconsistent with the bacteria number, the reasons were investigated in this paper. Results showed that irradiation had little effect on background luminescence, and there was no effect on luciferase-luminous system. When irradiation killed the bacteria, the ATPase activity also decreased. As a result, the ATP content in bacteria didn't decreased with the killed of bacteria, which contributed to the increase of free ATP in ATP extract and finally led to the disagreement between the bioluminescence intensity and the actual number of bacteria. When the free ATP in the dehydrated vegetable was removed, the bioluminescence intensity of ATP extract was consistent with the actual number of bacteria in irradiated dehydrated vegetable and ATP bioluminescence technology could be used in bacteria detection of irradiated samples. (authors)

COMPETITIVENESS THROUGH INFORMATION

Directory of Open Access Journals (Sweden)

Raluca Daniela RIZEA

2013-10-01

Full Text Available Intelligence competitiveness has already started to build its road in the company’s long term strategies. Nonetheless, business executives continue to look for ways to apply information technology strategically to their businesses. Using information managers manage to communicate, to convey their knowledge about markets, competitors, products, services and operations. Even if data and information are all over there are few amounts of managers that realize the importance of them to the success of the business. This article will review competitive forces and competitive information systems strategies for gaining competitive advantages, explain concepts of value chain, value co-opetition (competition and cooperation, and discuss innovation strategy. Co-opetition is a strategy whereby companies cooperate and compete at the same time with their competitors, complementors (i.e. hardware and software businesses, customers, suppliers. The article discuss an important dimension of information system, identifies competitive advantages and enhancing competitive strategies thought information systems.

Regional pest suppression associated with widespread Bt maize adoption benefits vegetable growers.

Science.gov (United States)

Dively, Galen P; Venugopal, P Dilip; Bean, Dick; Whalen, Joanne; Holmstrom, Kristian; Kuhar, Thomas P; Doughty, Hélène B; Patton, Terry; Cissel, William; Hutchison, William D

2018-03-27

Transgenic crops containing the bacterium Bacillus thuringiensis (Bt) genes reduce pests and insecticide usage, promote biocontrol services, and economically benefit growers. Area-wide Bt adoption suppresses pests regionally, with declines expanding beyond the planted Bt crops into other non-Bt crop fields. However, the offsite benefits to growers of other crops from such regional suppression remain uncertain. With data spanning 1976-2016, we demonstrate that vegetable growers benefit via decreased crop damage and insecticide applications in relation to pest suppression in the Mid-Atlantic United States. We provide evidence for the regional suppression of Ostrinia nubilalis (Hübner), European corn borer, and Helicoverpa zea (Boddie), corn earworm, populations in association with widespread Bt maize adoption (1996-2016) and decreased economic levels for injury in vegetable crops [peppers ( Capsicum annuum L.), green beans ( Phaseolus vulgaris L.), and sweet corn ( Zea mays L., convar. saccharata )] compared with the pre-Bt period (1976-1995). Moth populations of both species significantly declined in association with widespread Bt maize (field corn) adoption, even as increased temperatures buffered the population reduction. We show marked decreases in the number of recommended insecticidal applications, insecticides applied, and O. nubilalis damage in vegetable crops in association with widespread Bt maize adoption. These offsite benefits to vegetable growers in the agricultural landscape have not been previously documented, and the positive impacts identified here expand on the reported ecological effects of Bt adoption. Our results also underscore the need to account for offsite economic benefits of pest suppression, in addition to the direct economic benefits of Bt crops.

Putting competition into perspective

International Nuclear Information System (INIS)

Jones, L. III.

1993-01-01

This paper examines the current level of competition in the electric industry in the context of the history of the industry and the development of electric markets in other counties. The topics of the paper include competition in the history of the American electric industry, the current state of competition, the competitive situation in Texas, competition in other electric markets, and competitive changes in the US market

Analysis of physical characteristics of vegetable oils

Energy Technology Data Exchange (ETDEWEB)

Piamba Tulcan, Oscar Edwin [Universidade Nacional da Colombia (UNAL), Bogota (Colombia). Fac. de Ingenieria; Universidade Federal Fluminense (PGMEC/UFF), Niteroi, RJ (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica], E-mail: oepiambat@unal.edu.co; Andrade, Danielle Oliveira de; Andrade, Ednilton Tavares de [Universidade Federal Fluminense (TER/UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Agricola e do Meio Ambiente; Pereira, Roberto Guimaraes [Universidade Federal Fluminense (TER/UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

2008-07-01

Different vegetable oils were characterized using standardized methods. The evaluated characteristics were density, viscosity, flow point, cloud point and corrosion. The obtained data was tabulated and compared with average composition values of oils in percentage of fatty acids and iodine number for each oil. In this analysis it is shown that viscosity decreases with the increase of the iodine number, and density decrease. The cloud and flow point have greater relation with the presence of saturated or highly unsaturated fatty acids, respectively. The index of corrosion is greater when oil saturation or its iodine number are increased. (author)

Multinationals and Institutional Competitiveness

DEFF Research Database (Denmark)

Hull Kristensen, Peer; Morgan, Glenn

This article discusses how institutional competitiveness and multinationals are mutually enriching concepts. Seen from the perspective of Multinationals, institutional competitiveness becomes expressed at two levels. At the level of corporate HQs institutional competitiveness proves itself...... competitiveness of Liberal Market Economies and Coordinated Markets Economies under the current competitive regime....

Stable isotope signatures reflect competitiveness between trees under changed CO2/O3 regimes

International Nuclear Information System (INIS)

Grams, T.E.E.; Matyssek, R.

2010-01-01

Here we synthesize key findings from a series of experiments to gain new insight on inter-plant competition between juvenile beech (Fagus sylvatica) and spruce (Picea abies) under the influence of increased O 3 and CO 2 concentrations. Competitiveness of plants was quantified and mechanistically interpreted as space-related resource investments and gains. Stable isotopes were addressed as temporal integrators of plant performance, such as photosynthesis and its relation to water use and nitrogen uptake. In the weaker competitor, beech, efficiency in space-related aboveground resource investment was decreased in competition with spruce and positively related to Δ 13 C, as well as stomatal conductance, but negatively related to δ 18 O. Likewise, our synthesis revealed that strong belowground competition for water in spruce was paralleled in this species by high N assimilation capacity. We suggest combining the time-integrative potential of stable isotopes with space-related investigations of competitiveness to accomplish mechanistic understanding of plant competition for resources. - Combination of space-related concepts of competitiveness with stable isotopes has potential to clarify mechanisms of competition.

Climate, vegetation, distribution of taxa and diversity: A synthesis

International Nuclear Information System (INIS)

Nazrul-Islam, A.K.M.

2005-07-01

An attempt has been made to investigate from a range of viewpoints the principle of the climatic control of plant distribution. The accumulated plant weight (w) is related to the incoming solar radiation (S) and is dependent on leaf area index, the incoming solar radiation and the efficiency of solar radiation to dry matter conversion. A review is presented and a model is discussed in order to stimulate interest and knowledge in this crucial and central theme of ecology. The aim is to develop a model based on eco-physiological principles to predict the major vegetational zones of the globe. Predictions were based on various plant responses, such as low temperature survival and evapo-transpiration. Taxonomic diversity declined in a poleward direction; for both the northern and southern hemispheres family diversity is greatest near the equator, declined markedly from latitude 30 deg. to 90 deg. Strong correlation between family diversity and absolute minimum temperature exists and a regression line suggests a decrease of 3.3 families per deg. C reductions in minimum temperature. Analysis of the islands ecology differing in areas at various altitudes of the present and past has been most productive in providing means of investigating dispersal and migration and vertical diversity. Experimental studies have been attempted in herbaceous vegetation at different latitudes (tundra and British Isles) by clearing the native species (Carex bigelowii, Eriphorum vaginatum) of the area and by introducing exotic species such as Lolium perenne. The cover of the exotic species subsequently declined and ultimately became extinct and was covered by the native species. In order to investigate the climatic control of the distribution of taxa it becomes necessary to split the life (life cycles) of a plant into a number of stages, each of which is a link in the chain of survival and each of which can dominate the control of distribution. When a stage of life cycle is broken then

Climate, vegetation, distribution of taxa and diversity: A synthesis

Energy Technology Data Exchange (ETDEWEB)

Nazrul-Islam, A K.M. [Ecology Laboratory, Department of Botany, University of Dhaka, Dhaka (Bangladesh); Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)

2005-07-15

An attempt has been made to investigate from a range of viewpoints the principle of the climatic control of plant distribution. The accumulated plant weight (w) is related to the incoming solar radiation (S) and is dependent on leaf area index, the incoming solar radiation and the efficiency of solar radiation to dry matter conversion. A review is presented and a model is discussed in order to stimulate interest and knowledge in this crucial and central theme of ecology. The aim is to develop a model based on eco-physiological principles to predict the major vegetational zones of the globe. Predictions were based on various plant responses, such as low temperature survival and evapo-transpiration. Taxonomic diversity declined in a poleward direction; for both the northern and southern hemispheres family diversity is greatest near the equator, declined markedly from latitude 30 deg. to 90 deg. Strong correlation between family diversity and absolute minimum temperature exists and a regression line suggests a decrease of 3.3 families per deg. C reductions in minimum temperature. Analysis of the islands ecology differing in areas at various altitudes of the present and past has been most productive in providing means of investigating dispersal and migration and vertical diversity. Experimental studies have been attempted in herbaceous vegetation at different latitudes (tundra and British Isles) by clearing the native species (Carex bigelowii, Eriphorum vaginatum) of the area and by introducing exotic species such as Lolium perenne. The cover of the exotic species subsequently declined and ultimately became extinct and was covered by the native species. In order to investigate the climatic control of the distribution of taxa it becomes necessary to split the life (life cycles) of a plant into a number of stages, each of which is a link in the chain of survival and each of which can dominate the control of distribution. When a stage of life cycle is broken then

Interception and retention of technetium by vegetation and soil

International Nuclear Information System (INIS)

Hoffman, F.O.; Garten, C.T. Jr.; Huckabee, J.W.; Lucas, D.M.

1982-01-01

Field experiments were performed to quantify the initial interception and retention of technetium (Tc) by herbaceous vegetation as a consequence of direct deposition and uptake from soil. A simulated rain containing a solution of 95 /sup m/TcO 4 - was applied to plots of bare soil and plots with standing vegetation. Vegetation emerging in the baresoil plots obtained Tc predominantly from root uptake. Vegetation standing during the initial application obtained Tc from both direct foliar interception and root uptake. For the plots with standing vegetation, the estimated initial interception fraction (r) ranged from 0.079 to 0.17. The mass interception factor (r/Y/sub v/) ranged from 0.65 to 1.1 m 2 /kg. The retention of Tc by vegetation receiving direct foliar contamination varied with environmental half-times (T/sub w/) ranging from 15.9 to 18.7 days. Adjusting for the effects of growth dilution increased the values of T/sub w/ (range 21.6-28.7 days). For vegetation emerging from the plots of initial bare soil, retention was equivalent to a T/sub w/ of 43 days. These data indicated that uptake of Tc from soil diminished with time and that Tc was removed from plant tissue. In soil, a downward movement was evident, because Tc in the top 2 cm decreased with time and concentrations at lower soil depths (6-8 and 14-15 cm) and increased with time. The application of these data to predict steady-state concentrations of Tc in vegetation resulting from continuous deposition does not differ substantially from predictions based on the use of generic-default parameter values recommend in Regulatory Guide 1.109 of the U. S. Nuclear Regulatory Commission

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.

Welfare improving barter in imperfect competition

OpenAIRE

CRESTI, Barbara

2002-01-01

This paper offers a rationale for the development of the barter industry in industrialized economies. It argues that, in a context of imperfect competition, barter represents a profitable and efficient system of exchange. Thanks to barter, even if already at the optimum, a monopolist can still reduce the production costs and thus increase profits. Moreover, by adopting a barter strategy, he also improves social welfare, as he raises total output and decreases market price. Social welfare impr...

Menu-engineering in restaurants - adapting portion sizes on plates to enhance vegetable consumption: a real-life experiment.

NARCIS (Netherlands)

Reinders, M.J.; Huitink, M.; Dijkstra, S.C.; Maaskant, A.J.; Heijnen, J.

2017-01-01

Background: The aim of this research was to investigate whether increased portion sizes of vegetables and decreased portion sizes of meat on main dishes increased the amount of vegetables consumed in a real-life restaurant setting without affecting customer satisfaction. The participants were

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.

Where temperate meets tropical: Multi-factorial effects of elevated CO2, nitrogen enrichment, and competition on a mangrove-salt marsh community

Science.gov (United States)

McKee, K.L.; Rooth, J.E.

2008-01-01

Our understanding of how elevated CO2 and interactions with other factors will affect coastal plant communities is limited. Such information is particularly needed for transitional communities where major vegetation types converge. Tropical mangroves (Avicennia germinans) intergrade with temperate salt marshes (Spartina alterniflora) in the northern Gulf of Mexico, and this transitional community represents an important experimental system to test hypotheses about global change impacts on critical ecosystems. We examined the responses of A. germinans (C3) and S. alterniflora (C4), grown in monoculture and mixture in mesocosms for 18 months, to interactive effects of atmospheric CO2 and pore water nitrogen (N) concentrations typical of these marshes. A. germinans, grown without competition from S. alterniflora, increased final biomass (35%) under elevated CO2 treatment and higher N availability. Growth of A. germinans was severely curtailed, however, when grown in mixture with S. alterniflora, and enrichment with CO2 and N could not reverse this growth suppression. A field experiment using mangrove seedlings produced by CO2- and N-enriched trees confirmed that competition from S. alterniflora suppressed growth under natural conditions and further showed that herbivory greatly reduced survival of all seedlings. Thus, mangroves will not supplant marsh vegetation due to elevated CO2 alone, but instead will require changes in climate, environmental stress, or disturbance to alter the competitive balance between these species. However, where competition and herbivory are low, elevated CO2 may accelerate mangrove transition from the seedling to sapling stage and also increase above- and belowground production of existing mangrove stands, particularly in combination with higher soil N. ?? 2008 The Authors Journal compilation ?? 2008 Blackwell Publishing Ltd.

Welfare and competition effects of electricity interconnection between Ireland and Great Britain

International Nuclear Information System (INIS)

Malaguzzi Valeri, Laura

2009-01-01

This study analyzes the effects of additional interconnection on welfare and competition in the Irish electricity market. I simulate the wholesale electricity markets of the island of Ireland and Great Britain for 2005. I find that in order for the two markets to be integrated in 2005, additional interconnection would have to be large. The amount of interconnection decreases for high costs of carbon, since this causes the markets to become more similar. This suggests that in the absence of strategic behavior of firms, most of the gains from trade derive not from differences in size between countries, but from technology differences and are strongly influenced by fuel and carbon costs. Social welfare increases with interconnection, although at a decreasing rate. As the amount of interconnection increases, there are also positive effects on competition in Ireland, the less competitive of the two markets. Finally, it is unlikely that private investors will pay for the optimal amount of interconnection since their returns are significantly smaller than the total social benefit of interconnection. (author)

EDITORIAL: Physics competitions Physics competitions

Science.gov (United States)

Jordens, H.; Mathelitsch, L.

2011-07-01

International tests on competences, such as TIMSS or PISA, and knowledge of young students have revealed low average scores in many countries, often unexpectedly. One effective measure to increase the average standard of a population is to bring the last third of the group to a higher level. Therefore, many nations put some effort into this activity. This brings the danger that not enough attention is paid to students at the other end, those who are talented. Indeed, it is a very difficult task for a teacher to support the less able and at the same time challenge the gifted students, to lead them to the limits of their abilities and provide for a smooth transition to university study. Physics competitions have been proven to fulfil these last demands to a large degree, and therefore are an important additional and, to some extent, complementary tool for the promotion of talented students. This third special section on physics competitions in European Journal of Physics contains three papers, each dealing with a different form of science contest. The first continues the series of presentations of tasks performed at the International Young Physicists' Tournament, which was held in Vienna in 2011. First place went to the team from Singapore, and they have put their investigation on vertical oscillations of coupled magnets into written form (not required by the tournament, where an oral presentation and a defence and discussion are the central aspects). Their paper shows how rich in physics this problem is, and what level of solutions high-school students can already achieve. Sadly, those responsible for the organization of last year's International Physics Olympiad did not provide us with a report on this competition. This is unfortunate, since the Olympiad in Zagreb was very successful and, in particular, the experimental tasks were creative and demanding. Very similar to the aims and the execution of the Physics Olympiad is the International Olympiad on Astronomy

Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes: OC Oxidation Processes Across Vegetation

Energy Technology Data Exchange (ETDEWEB)

Graham, Emily B. [Pacific Northwest National Laboratory, Richland WA USA; Tfaily, Malak M. [Environmental Molecular Sciences Laboratory, Richland WA USA; Crump, Alex R. [Pacific Northwest National Laboratory, Richland WA USA; Goldman, Amy E. [Pacific Northwest National Laboratory, Richland WA USA; Bramer, Lisa M. [Pacific Northwest National Laboratory, Richland WA USA; Arntzen, Evan [Pacific Northwest National Laboratory, Richland WA USA; Romero, Elvira [Pacific Northwest National Laboratory, Richland WA USA; Resch, C. Tom [Pacific Northwest National Laboratory, Richland WA USA; Kennedy, David W. [Pacific Northwest National Laboratory, Richland WA USA; Stegen, James C. [Pacific Northwest National Laboratory, Richland WA USA

2017-12-01

In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here, we investigate biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically-bound (i.e., mineral and microbial) OC at terrestrial-aquatic interfaces. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the concept of ‘priming’—that inputs of water-soluble and thermodynamically-favorable terrestrial OC protects bound-OC from oxidation. Based on our results, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

Long-term decrease in satellite vegetation indices in response to environmental variables in an iconic desert riparian ecosystem: the Upper San Pedro, Arizona, United States

Science.gov (United States)

Nguyen, Uyen; Glenn, Edward P.; Nagler, Pamela L.; Scott, Russell L.

2015-01-01

The Upper San Pedro River is one of the few remaining undammed rivers that maintain a vibrant riparian ecosystem in the southwest United States. However, its riparian forest is threatened by diminishing groundwater and surface water inputs, due to either changes in watershed characteristics such as changes in riparian and upland vegetation, or human activities such as regional groundwater pumping. We used satellite vegetation indices to quantify the green leaf density of the groundwater-dependent riparian forest from 1984 to 2012. The river was divided into a southern, upstream (mainly perennial flow) reach and a northern, downstream (mainly intermittent and ephemeral flow) reach. Pre-monsoon (June) Landsat normalized difference vegetation index (NDVI) values showed a 20% drop for the northern reach (P  0·05). NDVI and enhanced vegetation index values were positively correlated (P deterioration of the riparian forest in the northern reach.

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

Directory of Open Access Journals (Sweden)

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.

[Effects of a long-term intervention in a work cafeteria on employee vegetable intake].

Science.gov (United States)

Misawa, Akemi; Yoshita, Katsushi; Fukumura, Tomoe; Tanaka, Taichiro; Tamaki, Junko; Takebayashi, Toru; Kusaka, Yukinori; Nakagawa, Hideaki; Yamato, Hiroshi; Okayama, Akira; Miura, Katsuyuki; Okamura, Tomonori; Ueshima, Hirotsugu

2015-01-01

We examined the effects on employee vegetable intake of a long-term intervention in an employee work cafeteria. The subjects were approximately 1,200 employees (aged 19-61 years) of an industrial company in Fukui prefecture. We promoted the intake of typical Japanese style meals that combined three elements (staple foods, main dishes and vegetable dishes) to increase vegetables intake. We displayed all items on the menus of the employee cafeteria using three colors (yellow, red and green to denote three elements) to indicate healthy food choices for the maintenance of a healthy food environment. We advised employees to choose meals containing the three elements at the time of payment, for nutritional education (appropriate portion choice: APC). We evaluated the ratio of APC at the same time. To calculate the mean daily intake per person, we carried out a questionnaire survey similar to the "semi-quantitative food frequency questionnaire" and asked about the frequency and approximate intake of vegetables. The APC was 63.5% after one year of intervention, significantly increased to 82.1% after two years (p breakfast (p < 0.001), lunch (p < 0.001) and dinner (p = 0.011), and from vegetable juice (p = 0.030) significantly increased after three years of intervention. The consumption of pickles significantly decreased after three years of intervention (p = 0.009). It was estimated that the vegetable intake of men increased from 167.3 to 184.6 g, and that of women from 157.9 to 187.7 g. Employee estimated vegetable intake was significantly increased and that of pickles was significantly decreased by a long-term intervention (three years) in the employee work cafeteria.

Increasing fruits and vegetables in midlife women: a feasibility study.

Science.gov (United States)

Gunn, Caroline A; Weber, Janet L; Coad, Jane; Kruger, Marlena C

2013-07-01

The positive link between bone health and fruit/vegetable consumption has been attributed to the lower renal acid load of a diet high in alkaline-forming fruit/vegetables. Other important dietary determinants of bone health include micronutrients and bioactives found in fruit/vegetables. We hypothesized that increased intake of fruit/vegetables to 9 or more servings a day would lower net endogenous acid production (NEAP) significantly (~20 mEq/d) and increase urine pH (0.5 pH units). This 8-week feasibility study investigated if 21 midlife women (age, 40-65 years) currently consuming 5 or less servings a day of fruit/vegetables could increase their intake to 9 or more servings a day to substantially lower NEAP and include specific vegetables daily. Three-day diet diaries were completed at baseline and the end of the study and assessed for NEAP (estimated) and number of servings from all food groups. Urine pH dipsticks were provided for the participants to assess and record their fasting urine pH daily (second void). Seventy-six percent of women achieved the study aim, which was to increase to 9 or more servings of fruit/vegetables for at least 5 d/wk. There was a reduction in the number of bread/cereal servings. Net endogenous acid production (estimated) was reduced significantly, with a mean urine pH increase of 0.68 pH units (95% confidence interval, 0.46-1.14); however, daily urine pH measures showed high variability. This study demonstrated that a group of midlife women can change their diet for 8 weeks by significantly increasing fruit/vegetable servings and include specific "bone friendly" vegetables daily, resulting in a significant decrease in estimated dietary NEAP and an increase in urine pH. Copyright © 2013 Elsevier Inc. All rights reserved.

Association analysis between spatiotemporal variation of vegetation greenness and precipitation/temperature in the Yangtze River Basin (China).

Science.gov (United States)

Cui, Lifang; Wang, Lunche; Singh, Ramesh P; Lai, Zhongping; Jiang, Liangliang; Yao, Rui

2018-05-23

The variation in vegetation greenness provides good understanding of the sustainable management and monitoring of land surface ecosystems. The present paper discusses the spatial-temporal changes in vegetation and controlling factors in the Yangtze River Basin (YRB) using Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) for the period 2001-2013. Theil-Sen Median trend analysis, Pearson correlation coefficients, and residual analysis have been used, which shows decreasing trend of the annual mean NDVI over the whole YRB. Spatially, the regions with significant decreasing trends were mainly located in parts of central YRB, and pronounced increasing trends were observed in parts of the eastern and western YRB. The mean NDVI during spring and summer seasons increased, while it decreased during autumn and winter seasons. The seasonal mean NDVI shows spatial heterogeneity due to the vegetation types. The correlation analysis shows a positive relation between NDVI and temperature over most of the YRB, whereas NDVI and precipitation show a negative correlation. The residual analysis shows an increase in NDVI in parts of eastern and western YRB and the decrease in NDVI in the small part of Yangtze River Delta (YRD) and the mid-western YRB due to human activities. In general, climate factors were the principal drivers of NDVI variation in YRB in recent years.

Vegetation Cover based on Eagleson's Ecohydrological Optimality in Northeast China Transect (NECT)

Science.gov (United States)

Cong, Z.; Mo, K.; Qinshu, L.; Zhang, L.

2016-12-01

Vegetation is considered as the indicator of climate, thus the study of vegetation growth and distribution is of great importance to cognize the ecosystem construction and functions. Vegetation cover is used as an important index to describe vegetation conditions. In Eagleson's ecohydrological optimality, the theoretical optimal vegetation cover M* can be estimated by solving water balance equations. In this study, the theory is applied in the Northeast China Transect (NECT), one of International Geosphere-Biosphere Programs (IGBP) terrestrial transects. The spatial distribution of actual vegetation cover M, which is derived from Normalized Vegetation Index (NDVI) from Moderate-resolution Imaging Spectroradiometer (MODIS), shows that there is a significant gradient ranging from 1 in the east forests to 0 in the west desert. The result indicates that the theoretical M* fits the actual M well (for forest, M* = 0.822 while M = 0.826; for grassland, M* = 0.353 while M = 0.352; the correlation coefficient between M and M* is 0.81). The reasonable calculated proportion of water balance components further demonstrates the applicability of the ecohydrological optimality theory. M* increases with the increase of LAI, leaf angle, stem fraction and temperature, and decreases with the increase of precipitation amount. This method offers the possibility to analyze the impacts of climate change to vegetation cover quantitatively, thus providing advices for eco-restoration projects.

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.

[Vegetation changes during the Holocene in the North Ibersá, Corrientes, Argentina].

Science.gov (United States)

Fernández Pacella, Lionel; Garralla, Silvina; Anzótegui, Luisa

2011-03-01

Vegetation changes during the Holocene in the North Iberá, Corrientes, Argentina. Wetlands are very important sites for palynological studies, since they represent one of the most suitable environments for fossil pollen preservation. The aim of this work was to determine, by palynological analysis of lacustrine sediments, the vegetal communities and the predominant environment during the Holocene in NW of Iberá. Two lagoons were studied: San Sebastián and San Juan Poriahú. Sediment samples were obtained with witness using a "Levingstone square-rod sampler", processed with Faegri e Iversen techniques and dated with C14. The palynological graphs were divided in zones using the Tilia program. The palynological analysis allowed visualizing diverse changes in the vegetation: from 6 140 +/- 50 to 5 170 +/- 100 a. C., the NW of Iberá was characterized by marsh-herbaceous vegetation and arboreal vegetation typical of dry vegetation. From 5 170 +/- 100 to 3 460 +/- 60 a. C., a decrease in the species frequency, typical of wet environments, is produced, and the clogging of the waterbody, from 3460 +/- 60 a. C. onwards, while continuing the dominance of herbaceous vegetation typical of these environments, the arboreal pollen, indicates the beginning of a hygrophilous forest development.

Project safety as a sustainable competitive advantage.

Science.gov (United States)

Rechenthin, David

2004-01-01

To be consistently profitable, a construction company must complete projects in scope, on schedule, and on budget. At the same time, the nature of the often high-risk work performed by construction companies can result in high accident rates. Clients and other stakeholders are placing increasing pressure on companies to decrease those accident rates. Clients routinely demand copies of safety plans and evidence of past results at the "pre-qualification" or "request for proposal" stages of the procurement process. Are high accident rates and the associated costs just a part of business? Companies that deliver on scope, schedule, and budget have a competitive advantage. Is it possible for projects with low accident rates to use it as a competitive advantage? Is the value added by safety just a temporary or parity issue, or does a successful safety program offer significant advantage to the company and the client? This article concludes that in the case of a high-risk industry, such as the construction industry, an organization with a successful safety program can promote safety performance as a sustainable competitive advantage. It is a choice the company can make.

Dynamical effects of vegetation on the 2003 summer heat waves

Science.gov (United States)

Stéfanon, M.

2012-04-01

dynamics of the terrestrial biosphere are simulated by the STOMATE module. STOMATE essentially simulates processes as photosynthesis, carbon allocation, litter decomposition, soil carbon dynamics, maintenance and growth respiration, and phenology. Finally, the long-term processes, including vegetation dynamics, fire, sapling establishment, light competition, and tree mortality are simulated according to the global vegetation model LPJ. Two MORCE simulations are performed at 15-km grid resolution, driven by ERA-INTERIM for 2002-2003. The first, called CTL, was conducted using an LAI prescribed after that of year 2002. The second simulation called MORCE, uses LAI explicitly calculated. These simulations are inter-compared to provide an estimate of the dynamical vegetation contribution to the two distinct heat wave during the summer 2003.

Single Tree Vegetation Depth Estimation Tool for Satellite Services Link Design

Directory of Open Access Journals (Sweden)

Z. Hasirci

2016-04-01

Full Text Available Attenuation caused by tree shadowing is an important factor for describing the propagation channel of satellite services. Thus, vegetation effects should be determined by experimental studies or empirical formulations. In this study, tree types in the Black Sea Region of Turkey are classified based on their geometrical shapes into four groups such as conic, ellipsoid, spherical and hemispherical. The variations of the vegetation depth according to different tree shapes are calculated with ray tracing method. It is showed that different geometrical shapes have different vegetation depths even if they have same foliage volume for different elevation angles. The proposed method is validated with the related literature in terms of average single tree attenuation. On the other hand, due to decrease system requirements (speed, memory usage etc. of ray tracing method, an artificial neural network is proposed as an alternative. A graphical user interface is created for the above processes in MATLAB environment named vegetation depth estimation tool (VdET.

Competition-colonization trade-offs, competitive uncertainty, and the evolutionary assembly of species.

Directory of Open Access Journals (Sweden)

Pradeep Pillai

Full Text Available We utilize a standard competition-colonization metapopulation model in order to study the evolutionary assembly of species. Based on earlier work showing how models assuming strict competitive hierarchies will likely lead to runaway evolution and self-extinction for all species, we adopt a continuous competition function that allows for levels of uncertainty in the outcome of competition. We then, by extending the standard patch-dynamic metapopulation model in order to include evolutionary dynamics, allow for the coevolution of species into stable communities composed of species with distinct limiting similarities. Runaway evolution towards stochastic extinction then becomes a limiting case controlled by the level of competitive uncertainty. We demonstrate how intermediate competitive uncertainty maximizes the equilibrium species richness as well as maximizes the adaptive radiation and self-assembly of species under adaptive dynamics with mutations of non-negligible size. By reconciling competition-colonization tradeoff theory with co-evolutionary dynamics, our results reveal the importance of intermediate levels of competitive uncertainty for the evolutionary assembly of species.

A spatio-temporal analysis of climatic drivers for observed changes in Sahelian vegetation productivity 1982-2007

DEFF Research Database (Denmark)

Kaspersen, Per; Fensholt, Rasmus; Huber Gharib, Silvia

2011-01-01

Linear trend analysis and seasonal trend analysis are performed on gridded data of vegetation, rainfall, solar radiation flux, and air temperature, in order to examine the influence of the past three decades of climate variability and change on the Sahelian vegetation dynamics. Per......-pixel correlation analyses are conducted on annual and monthly data, and analyses of change in the potential climatic constraints to the natural vegetation development from 1982–2007 are performed. The results reveal two distinct periods: (a) 1982–1994 marked by large increases in vegetation productivity...... and rainfall and little change in average air temperatures and solar radiation and (b) 1995–2007 characterized by no distinct trends in vegetation productivity and rainfall and increase in average air temperatures and decrease in solar radiation flux. Correlations between vegetation productivity and climatic...

Combined effects of climate change and forest clearing on the Amazon vegetation: Projections for 2080-2100

Science.gov (United States)

Cook, K. H.; Vizy, E. K.

2007-05-01

A regional climate model with resolution of 60 km coupled with a potential vegetation model is used to simulate future vegetation distributions over South America. The coupled model, which produces an accurate representation of today's climate and vegetation, is forced with increasing atmospheric CO2 concentrations, sea surface temperature from a global model, and scenarios of future land use practices to predict climate and vegetation distributions for the last 2 decades of the 21st century. When only climate change is considered, under a business-as-usual scenario for global emissions, the extent of the Amazon rainforest is reduced by about 70 per cent by the end of this century, and the shrubland (caatinga) vegetation of Brazil's Nordeste region spreads westward and southward. Reductions in annual mean precipitation are widespread and rainfall becomes insufficient to support the rainforest in these regions, but some areas receive more precipitation. The length of the dry season increases in the central and southern Amazon in association with changes in the large-scale tropical circulation. Without this change in seasonality, local refugia of Amazon vegetation would be preserved and the retreat of the rainforest would be somewhat less extensive. Including various projections of future land use practices in addition to climate change may accelerate the unrecoverable demise of the rainforest and feedback to modify climate on regional space scales. The portions of the rainforest that are most vulnerable to climate change are the same as those that are under the most pressure from human activity, presenting a remarkable competition.

Individual adjustment of sperm expenditure accords with sperm competition theory.

Science.gov (United States)

Pilastro, Andrea; Scaggiante, Marta; Rasotto, Maria B

2002-07-23

Sperm competition theory predicts that males should strategically allocate their sperm reserves according to the level of sperm competition, defined as the probability that the sperm of two males compete for fertilizing a given set of ova. Substantial evidence from numerous animal taxa suggests that, at the individual level, sperm expenditure increases when the risk of sperm competition is greater. In contrast, according to the "intensity model" of sperm competition [Parker, G. A., Ball, M. A., Stockley, P. & Gage, M. J. G. (1996) Proc. R. Soc. London Ser. B 263, 1291-1297], when more than two ejaculates compete during a given mating event, sperm expenditure should decrease as the number of competing males increases. Empirical evidence supporting this prediction, however, is still lacking. Here we measured sperm expenditure in two gobiid fishes, the grass (Zosterisessor ophiocephalus) and black goby (Gobius niger), in which up to six sneakers can congregate around the nest of territorial males and release their sperm when females spawn. We show that, in accordance with theory, sneaker males of both species release fewer sperm as the number of competitors increases.

The student-institution fit at university: Interactive effects of academic competition and social class on achievement goals.

Directory of Open Access Journals (Sweden)

Nicolas eSommet

2015-06-01

Full Text Available As compared to continuing-generation students, first-generation students are struggling more at university. In the present article, we question the unconditional nature of such a phenomenon and argue that it depends on structural competition. Indeed, most academic departments use harsh selection procedure all throughout the curriculum, fostering between-student competition. In these departments, first-generation students tend to suffer from a lack of student-institution fit, that is, inconsistencies with the competitive institution's culture, practices, and identity. However, one might contend that in less competitive academic departments continuing-generation students might be the ones experiencing a lack of fit. Using a cross-sectional design, we investigated the consequences of such a context- and category-dependent lack of fit on the endorsement of scholastically adaptive goals. We surveyed N = 378 first- and continuing-generation students from either a more competitive or a less competitive department in their first or final year of bachelor’s study. In the more competitive department, first-to-third year decrease of mastery goals (i.e., the desire to learn was found to be steeper for first- than for continuing-generation students. In the less competitive department, the reversed pattern was found. Moreover, first-to-third year decrease of performance goals (i.e., the desire to outperform others was found to be steeper within the less competitive department but did not depend on social class. This single-site preliminary research highlights the need to take the academic context into account when studying the social class graduation gap.

Romania's Competitiveness and Competitive Position in Global Context

Directory of Open Access Journals (Sweden)

Valentin NECULITA

2012-08-01

Full Text Available Competitiveness increase has become a primordial framework of the social and economic development strategies of most world countries (mainly the most developed ones over the last decades. The vigorous boost of the contemporary phenomenon of globalization, which has widened the global area of economies, sectors and firms confrontation, has laid an emphasis on their competitiveness importance for their favorable position in the international competition and has therefore force the status to take proper, broad and concerted measures to stimulate the determining factors of action and to take better advantage of their effects. The purpose of the paper is to determine whether an increase in competitiveness could reduce the disparities between regions. The E.U. Member States and regions need significant financial help to solve various structural problems and to achieve their potential of growth. Romania is no exception, one of the main problems being the low rate in attracting European funds.

Basketball shot types and shot success in different levels of competitive basketball.

Directory of Open Access Journals (Sweden)

Frane Erčulj

Full Text Available The purpose of our research was to investigate the relative frequencies of different types of basketball shots (above head, hook shot, layup, dunk, tip-in, some details about their technical execution (one-legged, two-legged, drive, cut, …, and shot success in different levels of basketball competitions. We analysed video footage and categorized 5024 basketball shots from 40 basketball games and 5 different levels of competitive basketball (National Basketball Association (NBA, Euroleague, Slovenian 1st Division, and two Youth basketball competitions. Statistical analysis with hierarchical multinomial logistic regression models reveals that there are substantial differences between competitions. However, most differences decrease or disappear entirely after we adjust for differences in situations that arise in different competitions (shot location, player type, and attacks in transition. Differences after adjustment are mostly between the Senior and Youth competitions: more shots executed jumping or standing on one leg, more uncategorised shot types, and more dribbling or cutting to the basket in the Youth competitions, which can all be attributed to lesser technical and physical ability of developing basketball players. The two discernible differences within the Senior competitions are that, in the NBA, dunks are more frequent and hook shots are less frequent compared to European basketball, which can be attributed to better athleticism of NBA players. The effect situational variables have on shot types and shot success are found to be very similar for all competitions.

Basketball shot types and shot success in different levels of competitive basketball.

Science.gov (United States)

Erčulj, Frane; Štrumbelj, Erik

2015-01-01

The purpose of our research was to investigate the relative frequencies of different types of basketball shots (above head, hook shot, layup, dunk, tip-in), some details about their technical execution (one-legged, two-legged, drive, cut, …), and shot success in different levels of basketball competitions. We analysed video footage and categorized 5024 basketball shots from 40 basketball games and 5 different levels of competitive basketball (National Basketball Association (NBA), Euroleague, Slovenian 1st Division, and two Youth basketball competitions). Statistical analysis with hierarchical multinomial logistic regression models reveals that there are substantial differences between competitions. However, most differences decrease or disappear entirely after we adjust for differences in situations that arise in different competitions (shot location, player type, and attacks in transition). Differences after adjustment are mostly between the Senior and Youth competitions: more shots executed jumping or standing on one leg, more uncategorised shot types, and more dribbling or cutting to the basket in the Youth competitions, which can all be attributed to lesser technical and physical ability of developing basketball players. The two discernible differences within the Senior competitions are that, in the NBA, dunks are more frequent and hook shots are less frequent compared to European basketball, which can be attributed to better athleticism of NBA players. The effect situational variables have on shot types and shot success are found to be very similar for all competitions.

Competition for transparency as a carrier of competition. Transparency needs in the European wholesale electricity markets

International Nuclear Information System (INIS)

Jong, Hanneke de; Hakvoort, Rudi

2005-01-01

This paper analyses different transparency aspects regarding European wholesale electricity markets and discusses transparency issues to be solved. In Europe, currently some progress has been made with respect to market transparency but transparency issues related to transmission, system operation and regulation have received little attention so far. Transmission system operators (TSOs) and regulatory authorities need certain market information in order to secure efficient competition. However, TSOs and regulatory authorities need to communicate themselves in order to facilitate competition and decrease uncertainty among market participants. Furthermore, considering ongoing market integration both TSOs and regulatory authorities must exchange information amongst themselves in order to facilitate coordination and monitoring activities. The effect of a higher level of transparency on effective competition is depended on two categories of transparency aspects: aspects that are related to transparency in the sense of open and adequate communication (perspicuity) and aspects that are related to the easiness to understand (clarity). Transparency includes both aspects. Pursuing overall harmonization of the European transparency level is important to fully profit from a higher level of (international) harmonization. Effective harmonization requires harmonization on all communication aspects. For Europe, with its many immature markets, the dilemma remains whether it is preferable to have less transparency with a high level of harmonization or to have a higher level of transparency but a lower level of harmonization. (Author)

Diversifying evolution of competitiveness.

Science.gov (United States)

Baldauf, Sebastian A; Engqvist, Leif; Weissing, Franz J

2014-10-29

In many species, individuals express phenotypic characteristics that enhance their competitiveness, that is, the ability to acquire resources in competition with others. Moreover, the degree of competitiveness varies considerably across individuals and in time. By means of an evolutionary model, we provide an explanation for this finding. We make the assumption that investment into competitiveness enhances the probability to acquire a high-quality resource, but at the same time reduces the ability of exploiting acquired resources with maximal efficiency. The model reveals that under a broad range of conditions competitiveness either converges to a polymorphic state, where individuals differing in competitive ability stably coexist, or is subject to perpetual transitions between periods of high and low competitiveness. The dynamics becomes even more complex if females can evolve preferences for (or against) competitive males. In extreme cases, such preferences can even drive the population to extinction.

Managing Multiple Sources of Competitive Advantage in a Complex Competitive Environment

Directory of Open Access Journals (Sweden)

Alexandre Howard Henry Lapersonne

2013-12-01

Full Text Available The aim of this article is to review the literature on the topic of sustained and temporary competitive advantage creation, specifically in dynamic markets, and to propose further research possibilities. After having analyzed the main trends and scholars’ works on the subject, it was concluded that a firm which has been experiencing erosion of its core sources of economic rent generation, should have diversified its strategy portfolio in a search for new sources of competitive advantage, ones that could compensate for the decline of profits provoked by intensive competitive environments. This review concludes with the hypothesis that firms, who have decided to enter and manage multiple competitive environments, should have developed a multiple strategies framework approach. The management of this source of competitive advantage portfolio should have allowed persistence of a firm’s superior economic performance through the management of diverse temporary advantages lifecycle and through a resilient effect, where a very successful source of competitive advantage compensates the ones that have been eroded. Additionally, the review indicates that economies of emerging countries, such as the ones from the BRIC block, should present a more complex competitive environment due to their historical nature of cultural diversity, social contrasts and frequent economic disruption, and also because of recent institutional normalization that has turned the market into hypercompetition. Consequently, the study of complex competition should be appropriate in such environments.

Crop–weed competition

DEFF Research Database (Denmark)

Gallandt, Eric R.; Weiner, Jacob

2015-01-01

importantly, weed density and time of emergence relative to the crop. Practices that (1) reduce the density of weeds, (2) maximise occupation of space or uptake of resources by the crop or (3) establish an early-season size advantage of the crop over the weeds will minimise the competitive effects of weeds...... on crops. Longer term management of crop–weed competition can be achieved through crop rotations, specifically crop sequences that reduce the weed seed bank, and therefore seedling density, and prevent proliferation of perennial weeds. Key ConceptsKey Concepts * Plant growth requires sunlight, water...... an early-season competitive advantage to the crop and (3) maximising resource capture by the crop using competitive species, competitive cultivars, high sowing densities, optimal spatial arrangement, intercropping complimentary species or transplanting....

The influence of roadside solid and vegetation barriers on near-road air quality

Science.gov (United States)

Ghasemian, Masoud; Amini, Seyedmorteza; Princevac, Marko

2017-12-01

The current study evaluates the influence of roadside solid and vegetation barriers on the near-road air quality. Reynolds Averaged Navier-Stokes (RANS) technique coupled with the k - ε realizable turbulence model is utilized to investigate the flow pattern and pollutant concentration. A scalar transport equation is solved for a tracer gas to represent the roadway pollutant emissions. In addition, a broad range of turbulent Schmidt numbers are tested to calibrate the scalar transport equation. Three main scenarios including flat terrain, solid barrier, and vegetative barrier are studied. To validate numerical methodology, predicted pollutant concentration is compared with published wind tunnel data. Results show that the solid barrier induces an updraft motion and lofts the vehicle emission plume. Therefore, the ground-level pollutant concentration decreases compared to the flat terrain. For the vegetation barrier, different sub-scenarios with different vegetation densities ranging from approximately flat terrain to nearly solid barrier are examined. Dense canopies act in a similar manner as a solid barrier and mitigate the pollutant concentration through vertical mixing. On the other hand, the high porosity vegetation barriers reduce the wind speed and lead to a higher pollutant concentration. As the vegetation density increases, i.e. the barrier porosity decreases, the recirculation zone behind the canopy becomes larger and moves toward the canopy. The dense plant canopy with LAD = 3.33m-2m3 can improve the near-road air quality by 10% and high porosity canopy with LAD = 1m-2m3 deteriorates near-road air quality by 15%. The results of this study can be implemented as green infrastructure design strategies by urban planners and forestry organizations.

Cost decreases in environmental technology. Evidence from four case studies

Energy Technology Data Exchange (ETDEWEB)

Oosterhuis, F. [Instituut for Environmental Studies, Vrije Universiteit VU, Amsterdam (Netherlands)

2007-07-15

The cost of a new technology tends to decrease as its uptake grows, and environmental technology is no exception to this general rule. Factors that can bring about such cost reductions include economies of scale, 'learning-by-doing', incremental technological improvements, and growing competition. In preparing environmental policies, the potential for future cost reductions is often disregarded. The present study aims to provide some additional empirical evidence on the cost decreases in environmental technology and the factors that lie behind them. To this end, four exemplary case studies have been selected. The first case (NOx emission abatement by Selective Catalytic Reduction (SCR)), shows a wide variety in cost estimates, without a clear trend. This is even true for the costs of a fairly homogeneous type of investment (SCR in coal fired power plants). Nevertheless, it is clear that an important cost decrease has been achieved by prolonging the lifetime of the catalyst, which is one of the main cost components in SCR. In the second case (NH3 emission abatement by chemical air scrubbers in pig farming) there is not yet sufficient experience with the technology to draw conclusions on the development of costs. However, it is already clear that economizing on the capacity of the system can contribute to important cost savings. Three-way catalytic converters in cars have shown significant price decreases following their large scale introduction on the European market in the early 1990s. Probably economies of scale have played an important role in this case, as the size of the market made mass production possible. To some extent, cost reductions may also be attributed to improvements such as the need for less materials (e.g. platinum). Furthermore, the performance of catalytic converters has improved, implying that the cost per unit of emission reduction has decreased even more than the cost of the device itself. Market prices of Compact Fluorescent Lamps

Competition between apex predators? Brown bears decrease wolf kill rate on two continents.

Science.gov (United States)

Tallian, Aimee; Ordiz, Andrés; Metz, Matthew C; Milleret, Cyril; Wikenros, Camilla; Smith, Douglas W; Stahler, Daniel R; Kindberg, Jonas; MacNulty, Daniel R; Wabakken, Petter; Swenson, Jon E; Sand, Håkan

2017-02-08

Trophic interactions are a fundamental topic in ecology, but we know little about how competition between apex predators affects predation, the mechanism driving top-down forcing in ecosystems. We used long-term datasets from Scandinavia (Europe) and Yellowstone National Park (North America) to evaluate how grey wolf ( Canis lupus ) kill rate was affected by a sympatric apex predator, the brown bear ( Ursus arctos ). We used kill interval (i.e. the number of days between consecutive ungulate kills) as a proxy of kill rate. Although brown bears can monopolize wolf kills, we found no support in either study system for the common assumption that they cause wolves to kill more often. On the contrary, our results showed the opposite effect. In Scandinavia, wolf packs sympatric with brown bears killed less often than allopatric packs during both spring (after bear den emergence) and summer. Similarly, the presence of bears at wolf-killed ungulates was associated with wolves killing less often during summer in Yellowstone. The consistency in results between the two systems suggests that brown bear presence actually reduces wolf kill rate. Our results suggest that the influence of predation on lower trophic levels may depend on the composition of predator communities. © 2017 The Authors.

A Conceptual Mapping Resource Advantage Theory, Competitive Advantage Theory, and Transient Competitive Advantage

OpenAIRE

Jasanta PERANGINANGIN

2015-01-01

Competitive advantage is the main purposed of the business entity focusing on market base view. Resource advantage theorists put their concern to empowering resources development with resources based view, in the other side needs to redefining competitive advantage. All the competitive advantage are transient, concluded the end of competitive advantage. Redefining competitive advantage by selling migration and shrewdness outward. This research to emphasize innovation capability rarely appears...

Microcystis aeruginosa strengthens the advantage of Daphnia similoides in competition with Moina micrura.

Science.gov (United States)

Tang, Hengxing; Hou, Xinying; Xue, Xiaofeng; Chen, Rui; Zhu, Xuexia; Huang, Yuan; Chen, Yafen

2017-08-31

Microcystis blooms are generally associated with zooplankton shifts by disturbing interspecific relationships. The influence of Microcystis on competitive dominance by different sized zooplanktons showed species-specific dependence. We evaluated the competitive responses of small Moina micrura and large Daphnia similoides to the presence of Microcystis using mixed diets comprising 0%, 20%, and 35% of toxic M. aeruginosa, and the rest of green alga Chlorella pyrenoidosa. No competitive exclusion occurred for the two species under the tested diet combinations. In the absence of M. aeruginosa, the biomasses of the two cladocerans were decreased by the competition between them. However, the Daphnia was less inhibited with the higher biomass, suggesting the competitive dominance of Daphnia. M. aeruginosa treatment suppressed the population growths of the two cladocerans, with the reduced carrying capacities. Nonetheless, the population inhibition of Daphnia by competition was alleviated by the increased Microcystis proportion in diet. As a result, the competitive advantage of Daphnia became more pronounced, as indicated by the higher Daphnia: Moina biomass ratio with increased Microcystis proportions. These results suggested that M. aeruginosa strengthens the advantage of D. similoides in competition with M. micrura, which contributes to the diversified zooplankton shifts observed in fields during cyanobacteria blooms.

Robotics Competitions: An Overview of First© Events and VEX© Competitions

Science.gov (United States)

Habib, Maria A.

2012-01-01

Robotics competitions generate excitement and raise the profile of a robotics program. This article provides an overview of robotics competitions, concentrating on those sponsored by FIRST (For Inspiration and Recognition of Science and Technology) and RECF (Robotics Education and Competition Foundation). FIRST® LEGO® League and VEX® robotics…

Evaluation of environmental and economic effectiveness of the Cross Compliance 4.3 Standards "Maintenance of olive groves and vineyards in good vegetative conditions"

Directory of Open Access Journals (Sweden)

Luigi Sansone

2015-11-01

Full Text Available This paper reports the first observations made in three farms of the Council for Agricultural Research and Economics (CREA relating to the environmental monitoring of the standard 4.3 maintenance of olive groves and vineyards in good vegetative conditions and analysis of differential of competitiveness  for both crops.

Flora and vegetation in Mikazukiike-Awara moor in northern Nagano prefecture, central Japan.

OpenAIRE

井田, 秀行; 湯本, 茂; 湯本, 静江

2003-01-01

Flora and vegetation were investigated in Mikazukiike-Awara moor in northern Nagano prefecture, central Japan. The vegetation was chiefly characterized by the Sphagnum-sedge community. We recorded 242 species of vascular plants and 4 sphagnum species in this area. Population of some Liliaceae and Orchidaceae species have decreased over the past 12 years. It may be caused by drought associated with human impacts. Additionally, conservation of peripheral environments (e.g. secondary beech fores...

[Variation trends of natural vegetation net primary productivity in China under climate change scenario].

Science.gov (United States)

Zhao, Dong-sheng; Wu, Shao-hong; Yin, Yun-he

2011-04-01

Based on the widely used Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ) for climate change study, and according to the features of natural environment in China, the operation mechanism of the model was adjusted, and the parameters were modified. With the modified LPJ model and taking 1961-1990 as baseline period, the responses of natural vegetation net primary productivity (NPP) in China to climate change in 1991-2080 were simulated under the Special Report on Emissions Scenarios (SRES) B2 scenario. In 1961-1990, the total NPP of natural vegetation in China was about 3.06 Pg C a(-1); in 1961-2080, the total NPP showed a fluctuant decreasing trend, with an accelerated decreasing rate. Under the condition of slight precipitation change, the increase of mean air temperature would have definite adverse impact on the NPP. Spatially, the NPP decreased from southeast coast to northwest inland, and this pattern would have less variation under climate change. In eastern China with higher NPP, especially in Northeast China, east of North China, and Loess Plateau, the NPP would mainly have a decreasing trend; while in western China with lower NPP, especially in the Tibetan Plateau and Tarim Basin, the NPP would be increased. With the intensive climate change, such a variation trend of NPP would be more obvious.

Antimicrobial Effect of Extracts of Cruciferous Vegetables

Directory of Open Access Journals (Sweden)

Shu-Hui Hu

2004-12-01

Full Text Available The cruciferous vegetables cauliflower, broccoli, cabbage, Chinese radish, Chinese kale, and Chinese kitam were used in this study to prepare water-soluble and methanol-water extracts. Crude protein extracts were also obtained by diethylaminoethyl (DEAE anion exchange chromatography. Water-soluble polysaccharides were prepared by ethanol precipitation followed by ultrafiltration. The antimicrobial effects of all these extracts were evaluated against Gram-positive bacteria, Gram-negative bacteria, and yeast. Crude protein extracts exhibited the greatest antimicrobial activity in monoculture experiments. The antimicrobial effects of cruciferous vegetables were also studied by steeping beef, carrot, and celery in chlorine (10 ppm or citric acid solution (1% containing the crude protein extract (500 ppm for different time periods. Total aerobic plate counts and coliform counts on these foods decreased significantly after 10 minutes in all steeping solutions (p < 0.05.

Anti- versus Pro-Competitive Mergers

OpenAIRE

Fridolfsson, Sven-Olof

2007-01-01

In a framework where mergers are mutually excluding, I show that firms pursue anti- rather than (alternative) pro-competitive mergers. Potential outsiders to anti-competitive mergers refrain from pursuing pro-competitive mergers if the positive externalities from anti-competitive mergers are strong enough. Potential outsiders to pro-competitive mergers pursue anti-competitive mergers if the negative externalities from the pro-competitive mergers are strong enough. Potential participants in an...

Impact of urban gardening in equatorial zone on soils and metal transfer to vegetables

Directory of Open Access Journals (Sweden)

Ondo Aubin Jean

2013-01-01

Full Text Available This study aimed at assessing the impact of urban agriculture on physicochemical soil properties and the metal uptake by some leafy vegetables cultivated in urban soils of Libreville, Gabon. Cultivated and uncultivated top-soil and vegetable samples were collected on two urban garden sites, and analyzed. The results showed that there was strong acidification and a decrease of nutrient and metal concentrations in soils due of agricultural practices. The metal transfer to plants was important, with the exception of iron. The non-essential metal cadmium and lead were not detectable in plant tissues. Amaranth accumulated more metals than other vegetables. Amaranth and Roselle were vegetables that preferentially concentrated metals in their leaves and can therefore be used for metal supplementation in food chain.

Studies of food folates and folic acid deficiency by radioligand competitive binding assay techniques. Part of a coordinated programme on in vitro assay techniques

International Nuclear Information System (INIS)

Hettiarachchy, N.S.

1981-01-01

Conjugese extracted from winged bean or sweet potato leaves was used to release folate from Sri Lankan foodstuffs. Total folate was then estimated by competitive binding assay using goat milk as binding agent. Of 33 foodstuffs investigated, green gram, cow pea, and red gram among the pulses and mukunuvenna, amaranth and centella among the leafy vegetables were shown to be rich sources of folate. Between 20 and 60% of total folate was lost when such foodstuffs were boiled for 60 minutes. It is thus advisable that pulses and leafy vegetables be boiled only for the minimum time necessary for tenderization before consumption

Evaluation of environmental and economic effectiveness of the Cross Compliance 4.3 Standard ‘Maintenance of olive groves and vineyards in good vegetative conditions’

Directory of Open Access Journals (Sweden)

Luigi Sansone

2015-11-01

Full Text Available This paper reports the first observations made in three farms of the Council for Agricultural Research and Economics (CREA relating to the environmental monitoring of the Standard 4.3 'Maintenance of olive groves and vineyards in good vegetative conditions' and analysis of differential of competitiveness for both crops.

Approximate kernel competitive learning.

Science.gov (United States)

Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

2015-03-01

Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches. Copyright © 2014 Elsevier Ltd. All rights reserved.

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....

Impacts of changes in vegetation cover on soil water heat coupling in an alpine meadow of the Qinghai-Tibet Plateau, China

Directory of Open Access Journals (Sweden)

W. Genxu

2009-03-01

Full Text Available Alpine meadow is one of the most widespread grassland types in the permafrost regions of the Qinghai-Tibet Plateau, and the transmission of coupled soil water heat is one of the most crucial processes influencing cyclic variations in the hydrology of frozen soil regions, especially under different vegetation covers. The present study assesses the impact of changes in vegetation cover on the coupling of soil water and heat in a permafrost region. Soil moisture (θ_v, soil temperature (T_s, soil heat content, and differences in θ_v−T_s coupling were monitored on a seasonal and daily basis under three different vegetation covers (30, 65, and 93% on both thawed and frozen soils. Regression analysis of θ_v vs. T_s plots under different levels of vegetation cover indicates that soil freeze-thaw processes were significantly affected by the changes in vegetation cover. The decrease in vegetation cover of an alpine meadow reduced the difference between air temperature and ground temperature (ΔT_a−s, and it also resulted in a decrease in T_s at which soil froze, and an increase in the temperature at which it thawed. This was reflected in a greater response of soil temperature to changes in air temperature (T_a. For ΔT_a−s outside the range of −0.1 to 1.0°C, root zone soil-water temperatures showed a significant increase with increasing ΔT_a−s; however, the magnitude of this relationship was dampened with increasing vegetation cover. At the time of maximum water content in the thawing season, the soil temperature decreased with increasing vegetation. Changes in vegetation cover also led to variations in θ_v−T_s coupling. With the increase in vegetation cover, the surface heat flux decreased. Soil heat storage at 20 cm in

Effect of brain-derived neurotrophic factor on the formation of psycho-vegetative syndrome with brain injury

Directory of Open Access Journals (Sweden)

Selyanina N.V.

2016-09-01

Full Text Available Aim: to determine the role of brain-derived neurotrophic factor in the formation and forecasting of psycho-vegetative syndrome in patients with cerebral mild to moderate injury. Material and Methods. There have been 150 patients with contusion of the brain, examined. Indicators of neurological, psycho-vegetative status, quantitative content of brain-derived neurotrophic factor (BDNF and nerve growth factor (NGF in the serum were studied. Results. At patients with brain contusion neurological, psycho-vegetative disturbances and decrease neurotrophic factors are determined. It was found to depend of the content of BDNF and psycho-vegetative indicators. Conclusion. The level of brain-derived neurotrophic factor serum (less than 300 pg/ml is a predictor of psycho-vegetative syndrome in the long term of the brain injury.

Coal competitiveness?

International Nuclear Information System (INIS)

Rogeaux, B.

2006-01-01

Will coal electrical plants be more competitive in the coming years? Answering this one cannot be limited to merely comparing estimates based on reference electricity production costs. The competitiveness of coal will indeed depend on the final product marketed, as the MWhs are not equal: is the purpose to produce base, half-base MWh? Does the electrical equipment structure require flexible MWh (for instance in the event of significant intermittent renewable energy amounts), and therefore plants able to adjust their power rapidly? But the competitiveness of coal will also depend on many factors that will correct reference cost estimates: uncertainties, risks, externalities. These factors will need to be appreciated on a case by case basis. We introduce some of the reasoning used to better appreciate the future competitiveness of coal, and the main factors conditioning it in three contrasting regions of the world: Europe, USA, china. (author)

GLOBAL COMPETITION AND ROMANIA’S NATIONAL COMPETITIVE ADVANTAGE

Directory of Open Access Journals (Sweden)

Pop Nicolae Alexandru

2013-07-01

Full Text Available Analyzing products and services around us it is clear that most of them are the result of production factors, labor and capital becoming more international and increasingly less and less national. We are witnessing the globalization of markets and production, to a large global integration and interdependence, increase personalization of production and services as a result of new communication systems interaction and flexible production processes. Markets will continue to homogenize and diversify at the same time, so it is important that as a global marketer one addresses a market segment defined by income, age, and consumption habits and not by membership of a nation. The most visible and polarized is the premium segment fighting for high income clients where brand value plays an important role. Instead identification of large segments of customers offers the advantages of scale economy in production and marketing for global enterprises. Consumer profile is the dominant global consumer requesting and accepting global products and services easily. In fact, what can force an economic alignment to achieve the best performance, rather than the global consumer. The research methodology used includes literature review, comparative analysis, synthesis of data based on bibliographic resources and official documents.The aim of the paper is to highlight current models that underlie the competitive advantage of nations and assess the competitive advantage of Romania in the context of the global market. A case study is used to offer an overview of competitive advantage of Antibiotice Iasi SA, a competitive player, in a global pharmaceutical market with strong global competition. Countries moderate companies’ achievements of global efficiency objectives due to the countries’ rivalry. Romania has to understand that it is in competition with other countries in order to fulfill economic, political and social objectives. The scope in the end is the well

The effect of professional dietary counseling: elite basketball players eat healthier during competition days.

Science.gov (United States)

Tsoufi, Anastasia; Maraki, Maria I; Dimitrakopoulos, Leonidas; Famisis, Konstantinos; Grammatikopoulou, Maria G

2017-10-01

Literature suggests that dietary intake of elite athletes may differ between training and competition days. In addition, despite the importance of nutrition in sports and the popularity of basketball, studies on the diet of basketball players are scarce. Therefore, the aim of the present study was to assess dietary intake and diet quality in training and competition days in a team of elite basketball players receiving daily professional nutritional counseling. One elite basketball team (N.=15) participating in EuroLeague volunteered for the study. The team employed a certified dietitian, responsible for providing individualized nutritional evaluation and counseling, dietary planning and supervision of the diet of all the players. Dietary intake was assessed using 24-hour recalls and the Healthy Eating Index (HEI) was then calculated. All players exhibited adequate (i.e., >80) HEI score (raw and adjusted for energy intake [EI]), on both training and competition days. Although daily energy, carbohydrate and protein intakes were greater during training compared to competition days (26.0 [21.7, 26.4] vs. 19.5 [19.3, 22.1] MJ, 7.6±1.5 vs. 6.8±0.9 g/kg of body weight [BW] and 2.6±0.6 vs. 2.2±0.2 g/kg BW, respectively; all Pvs. 94.0 [94.0, 94.0] and 89.7 [88.4, 89.7] vs. 92.7 [91.7, 92.8], respectively; all P≤0.001) due to lower total grains, whole grains and total vegetables consumption and greater saturated fats consumption (Psports dietitians exhibit adequate diet quality, with the highest possible observed during competition days.

Use of satellite imagery to identify vegetation cover changes following the Waldo Canyon Fire event, Colorado, 2012-2013

Science.gov (United States)

Cole, Christopher J.; Friesen, Beverly A.; Wilson, Earl M.

2014-01-01

The Waldo Canyon Fire of 2012 was one of the most destructive wildfire events in Colorado history. The fire burned a total of 18,247 acres, claimed 2 lives, and destroyed 347 homes. The Waldo Canyon Fire continues to pose challenges to nearby communities. In a preliminary emergency assessment conducted in 2012, the U.S. Geological Survey (USGS) concluded that drainage basins within and near the area affected by the Waldo Canyon Fire pose a risk for future debris flow events. Rainfall over burned, formerly vegetated surfaces resulted in multiple flood and debris flow events that affected the cities of Colorado Springs and Manitou Springs in 2013. One fatality resulted from a mudslide near Manitou Springs in August 2013. Federal, State, and local governments continue to monitor these hazards and other post-fire effects, along with the region’s ecological recovery. At the request of the Colorado Springs Office of Emergency Management, the USGS Special Applications Science Center developed a geospatial product to identify vegetation cover changes following the 2012 Waldo Canyon Fire event. Vegetation cover was derived from July 2012 WorldView-2 and September 2013 QuickBird multispectral imagery at a spatial resolution of two meters. The 2012 image was collected after the fire had reached its maximum extent. Per-pixel increases and decreases in vegetation cover were identified by measuring spectral changes that occurred between the 2012 and 2013 image dates. A Normalized Difference Vegetation Index (NDVI), and Green-Near Infrared Index (GRNIR) were computed from each image. These spectral indices are commonly used to characterize vegetation cover and health condition, due to their sensitivity to detect foliar chlorophyll content. Vector polygons identifying surface-cover feature boundaries were derived from the 2013 imagery using image segmentation software. This geographic software groups similar image pixels into vector objects based upon their spatial and spectral

Menu-engineering in restaurants - adapting portion sizes on plates to enhance vegetable consumption: a real-life experiment.

Science.gov (United States)

Reinders, Machiel J; Huitink, Marlijn; Dijkstra, S Coosje; Maaskant, Anna J; Heijnen, Joris

2017-12-25

The aim of this research was to investigate whether increased portion sizes of vegetables and decreased portion sizes of meat on main dishes increased the amount of vegetables consumed in a real-life restaurant setting without affecting customer satisfaction. The participants were unaware of the experiment. A cross-over design was used in which three restaurants were randomly assigned to a sequence of an intervention and control condition. In the intervention period, the vegetable portion sizes on the plates of main dishes were doubled (150 g of vegetables instead of 75 g) and the portion sizes of meat on the plates were reduced by an average of 12.5%. In the control period, the portion sizes of the main dishes were maintained as usual. In total, 1006 observations and questionnaires were included. Vegetable consumption from plates was significantly higher during the intervention period (M = 115.5 g) than during the control period (M = 61.7 g). Similarly, total vegetable consumption (including side dishes) was significantly higher during the intervention period (M = 178.0 g) than during the control period (M = 137.0 g). Conversely, meat consumption was significantly lower during the intervention period (M = 183.1 g) than during the control period (M = 211.1 g). Satisfaction with the restaurant visit did not differ between the intervention period (M = 1.27) and control period (M = 1.35). Satisfaction with the main dish was significantly lower during the intervention period (M = 1.25) than during the control period (M = 1.38), although in both cases, the scores indicated that participants remained (very) satisfied with their main dish. This study showed that increasing vegetable portions in combination with decreasing meat portions (unknowingly to the consumer) increased the amount of vegetables consumed and decreased the amount of meat consumed. Furthermore, despite the changes in portion sizes, participants remained satisfied

ASSESSMENT OF VEGETATION COVER ON SODA WASTE DISPOSAL SITE AT JANIKOWO, FOLLOWING 13-YEAR-LONG RECLAMATION

Directory of Open Access Journals (Sweden)

Kazimierz Henryk Dyguś

2014-10-01

Full Text Available The results are presented of vegetation survey on the alkaline and saline soda waste disposal site at Janikowo Soda Plant near Toruń (central Poland. The site was subject to reclamation using diverse techniques including sewage sludge and ash, starting from the year 2000 onwards. The survey was made to evaluate the status of plant succession as well as stability and diversity of vegetation cover. The vegetation was inventoried using the cover-frequency method, on a 10 x 10 m quadrat samples randomly distributed over the reclaimed area. Communities were classified using the Central-European approach by Braun-Blanquet (1964. In 2013, the vegetation was well established and provided a dense cover of the substrate. 108 plant species were found compared to some 5–8 plants which arrived spontaneously until the year 2000. Species richness increased 15 fold since the year when reclamation started. Species of graminoid and Asteraceae families prevailed in most patches of local vegetation. The vegetation cover on sites treated with a mixt of power plant ash and sewage sludge was less stable and less diverse than that on sites where sewage sludge only was applied. Annuals and biennials dominated in the vegetation on ash grounds while more competitive perennials prevailed on sewage sludge substrates. On the latter substrates there develop plant communities classified as an association of smooth meadow grass and common yarrow Poa pratensis-Achillea millefolium, whose species combination closely resembles that of seminatural fresh meadows. On the ash grounds, a variety of associations of ruderal plants were found with dominating Loesel mustard and common mugwort Sisymbrium loeselii-Artemisia vulgaris. Phytoindicatory methods using Ellenberg values have shown that waste substrates contained increased salt concentrations, however, there was no indication of increased heavy metal contents, as no plants tolerating excessive amounts of heavy metals were

Biofuels in Spain: Market penetration analysis and competitiveness in the automotive fuel market

International Nuclear Information System (INIS)

Sobrino, Fernando Hernandez; Monroy, Carlos Rodriguez; Perez, Jose Luis Hernandez

2010-01-01

For several years the European Union (E.U.) has been promoting the use of biofuels due to their potential benefits such as the reduction of dependence on foreign energy imports (the raw materials can be produced within the E.U.), the more stable fossil fuel prices (they can replace fossil fuels on the market), the greenhouse gas (GHG) reduction (biofuels' raw materials fix CO 2 from the atmosphere) and the fact that they can represent an additional source of income for the primary sector (biofuels' raw materials are vegetables that can be grown and harvested). Despite the public aids (direct and indirect), biofuels are not competitive with fossil fuels at present, but it is possible that in the future the environment conditions change and biofuels might become competitive. It is difficult to assess whether this will happen or not, but it is possible to make an assessment of a future situation. This article presents two analyses with one objective: to determine if biofuels might become competitive in the future. The first analysis examines the dependencies of two quotations which have a strong relationship with fuels: the crude oil quotation and the CO 2 bond quotation. The analysis of these relationships may help to forecast the future competitiveness of biofuels. For instance, biofuels' future competitiveness will be higher if their raw material costs are not related to crude oil quotations or if they are related in a negative way (the higher the crude oil quotations the lower the raw material biofuels' cost). The second analysis focuses on the market penetration of biofuels in the Spanish market. There are data related to biofuels monthly consumption in Spain since 2007 and it is possible to know if biofuels are gaining market quota since then. (author)

Biofuels in Spain: Market penetration analysis and competitiveness in the automotive fuel market

Energy Technology Data Exchange (ETDEWEB)

Sobrino, Fernando Hernandez; Monroy, Carlos Rodriguez [Department of Business Administration, School of Industrial Engineering, Universidad Politecnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Perez, Jose Luis Hernandez [High School Chemistry Teacher, Madrid (Spain)

2010-12-15

For several years the European Union (E.U.) has been promoting the use of biofuels due to their potential benefits such as the reduction of dependence on foreign energy imports (the raw materials can be produced within the E.U.), the more stable fossil fuel prices (they can replace fossil fuels on the market), the greenhouse gas (GHG) reduction (biofuels' raw materials fix CO{sub 2} from the atmosphere) and the fact that they can represent an additional source of income for the primary sector (biofuels' raw materials are vegetables that can be grown and harvested). Despite the public aids (direct and indirect), biofuels are not competitive with fossil fuels at present, but it is possible that in the future the environment conditions change and biofuels might become competitive. It is difficult to assess whether this will happen or not, but it is possible to make an assessment of a future situation. This article presents two analyses with one objective: to determine if biofuels might become competitive in the future. The first analysis examines the dependencies of two quotations which have a strong relationship with fuels: the crude oil quotation and the CO{sub 2} bond quotation. The analysis of these relationships may help to forecast the future competitiveness of biofuels. For instance, biofuels' future competitiveness will be higher if their raw material costs are not related to crude oil quotations or if they are related in a negative way (the higher the crude oil quotations the lower the raw material biofuels' cost). The second analysis focuses on the market penetration of biofuels in the Spanish market. There are data related to biofuels monthly consumption in Spain since 2007 and it is possible to know if biofuels are gaining market quota since then. (author)

Permafrost warming and vegetation changes in continental Antarctica

International Nuclear Information System (INIS)

Guglielmin, Mauro; Dalle Fratte, Michele; Cannone, Nicoletta

2014-01-01

Continental Antarctica represents the last pristine environment on Earth and is one of the most suitable contexts to analyze the relations between climate, active layer and vegetation. In 2000 we started long-term monitoring of the climate, permafrost, active layer and vegetation in Victoria Land, continental Antarctica. Our data confirm the stability of mean annual and summer air temperature, of snow cover, and an increasing trend of summer incoming short wave radiation. The active layer thickness is increasing at a rate of 0.3 cm y −1 . The active layer is characterized by large annual and spatial differences. The latter are due to scarce vegetation, a patchy and very thin organic layer and large spatial differences in snow accumulation. The active layer thickening, probably due to the increase of incoming short wave radiation, produced a general decrease of the ground water content due to the better drainage of the ground. The resultant drying may be responsible for the decline of mosses in xeric sites, while it provided better conditions for mosses in hydric sites, following the species-specific water requirements. An increase of lichen vegetation was observed where the climate drying occurred. This evidence emphasizes that the Antarctic continent is experiencing changes that are in total contrast to the changes reported from maritime Antarctica. (paper)

FIRST 2002, 2003, 2004 Robotics Competition(s)

Science.gov (United States)

Purman, Richard

2004-01-01

The New Horizons Regional Education Center (NHREC) in Hampton, VA sought and received NASA funding to support its participation in the 2002, 2003, and 2004 FIRST Robotics Competitions. FIRST, Inc. (For Inspiration and Recognition of Science and Technology) is an organization which encourages the application of creative science, math, and computer science principles to solve real-world engineering problems. The FIRST competition is an international engineering contest featuring high school, government, and business partnerships.

Changes of Vegetation Distribution in the East Dongting Lake After the Operation of the Three Gorges Dam, China

Directory of Open Access Journals (Sweden)

Jia-Yu Hu

2018-05-01

Full Text Available Water regime is regarded as the primary factor influencing the vegetation distribution in natural wetland ecosystems. However, the effect of water regime change induced by large-scale hydraulic engineering on vegetation distribution is still unclear. In this study, multi-temporal TM/ETM+/OLI images and hydrological data from 1995 to 2015 were used to elucidate how the change in water regime influenced the vegetation distribution in the East Dongting Lake (EDTL, especially after the operation of the Three Gorges Dam (TGD in 2003. Using unsupervised and supervised classification methods, three types of land cover were identified in the study area: Water and Mudflat, Grass, and Reed and Forest. Results showed that the total vegetation area in EDTL increased by approximately 78 km2 during 1995–2015. The areas of Reed and Forest and Grass exhibited a contrasting trend, dramatic increase in Reed and Forest but sharp decrease in Grass, particularly after the operation of TGD. The lowest distribution elevations of Grass and Reed and Forest decreased by 0.61 and 0.52 m, respectively. As a result of water level variation, submergence duration increased at 20–21 m and 28 m elevations (1–13 days, but significantly decreased at 22–27 m and 29–30 m elevations (-3 to -31 days. The submergence duration of Grass and Reed and Forest was 246 and 177 days, respectively. This study indicated that wetland vegetation pattern significantly changed after the operation of TGD, mainly as a result of changes in submergence condition. Submergence duration might be an effective indicator to predict the shift of vegetation distribution in EDTL, and which could provide scientific guidance for vegetation restoration and wetland management in this lake.

The human operational sex ratio: effects of marriage, concealed ovulation, and menopause on mate competition.

Science.gov (United States)

Marlowe, Frank W; Berbesque, J Colette

2012-12-01

Among mammals, male-male competition for sexual access to females frequently involves fighting. Larger body size gives males an advantage in fighting, which explains why males tend to be larger than females in many species, including anthropoid primates. Mitani et al. derived a formula to measure the operational sex ratio (OSR) to reflect the degree of male-male competition using the number of reproductively available males to females who are cycling and capable of conceiving. The OSR should predict the degree of sexual dimorphism in body mass-at least if male-male competition involves much fighting or threatening. Here, we use hunter-gatherer demographic data and the Mitani et al. formula to calculate the human OSR. We show that humans have a much lower degree of body mass sexual dimorphism than is predicted by our OSR. We suggest this is because human competition rarely involves fighting. In human hunter-gatherer societies, differences in the ages of marriage have an impact on competition in that the age of males at first marriage is younger when there is a lower percentage of married men with two or more wives, and older when there is a higher percentage of married men with two or more wives. We discuss the implications of this for females, along with the effects of two key life history traits that influence the OSR, concealed ovulation and menopause. While menopause decreases the number of reproductively available females to males and thus increases male-male competition, concealed ovulation decreases male-male competition. Finally, we discuss the importance of mostly monogamous mate bonds in human evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment

Directory of Open Access Journals (Sweden)

K. Edmaier

2011-05-01

Full Text Available The establishment of riparian pioneer vegetation is of crucial importance within river restoration projects. After germination or vegetative reproduction on river bars juvenile plants are often exposed to mortality by uprooting caused by floods. At later stages of root development vegetation uprooting by flow is seen to occur as a consequence of a marked erosion gradually exposing the root system and accordingly reducing the mechanical anchoring. How time scales of flow-induced uprooting do depend on vegetation stages growing in alluvial non-cohesive sediment is currently an open question that we conceptually address in this work. After reviewing vegetation root issues in relation to morphodynamic processes, we then propose two modelling mechanisms (Type I and Type II, respectively concerning the uprooting time scales of early germinated and of mature vegetation. Type I is a purely flow-induced drag mechanism, which causes alone a nearly instantaneous uprooting when exceeding root resistance. Type II arises as a combination of substantial sediment erosion exposing the root system and resulting in a decreased anchoring resistance, eventually degenerating into a Type I mechanism. We support our conceptual models with some preliminary experimental data and discuss the importance of better understanding such mechanisms in order to formulate sounding mathematical models that are suitable to plan and to manage river restoration projects.

Responses of the Carbon Storage and Sequestration Potential of Forest Vegetation to Temperature Increases in Yunnan Province, SW China

Directory of Open Access Journals (Sweden)

Ruiwu Zhou

2018-04-01

Full Text Available The distribution of forest vegetation and forest carbon sequestration potential are significantly influenced by climate change. In this study, a map of the current distribution of vegetation in Yunnan Province was compiled based on data from remote sensing imagery from the Advanced Land Observing Satellite (ALOS from 2008 to 2011. A classification and regression tree (CART model was used to predict the potential distribution of the main forest vegetation types in Yunnan Province and estimate the changes in carbon storage and carbon sequestration potential (CSP in response to increasing temperature. The results show that the current total forest area in Yunnan Province is 1.86 × 107 ha and that forest covers 48.63% of the area. As the temperature increases, the area of forest distribution first increases and then decreases, and it decreases by 11% when the temperature increases from 1.5 to 2 °C. The mean carbon density of the seven types of forest vegetation in Yunnan Province is 84.69 Mg/ha. The total carbon storage of the current forest vegetation in Yunnan Province is 871.14 TgC, and the CSP is 1100.61 TgC. The largest CSP (1114.82 TgC occurs when the temperature increases by 0.5 °C. Incremental warming of 2 °C will sharply decrease the forest CSP, especially in those regions with mature coniferous forest vegetation. Semi-humid evergreen broad-leaved forests were highly sensitive to temperature changes, and the CSP of these forests will decrease with increasing temperature. Warm-hot coniferous forests have the greatest CSP in all simulation scenarios except the scenario of a 2 °C temperature increase. These results indicate that temperature increases can influence the CSP in Yunnan Province, and the largest impact emerged in the 2 °C increase scenario.

Dehydration and acute weight gain in mixed martial arts fighters before competition.

Science.gov (United States)

Jetton, Adam M; Lawrence, Marcus M; Meucci, Marco; Haines, Tracie L; Collier, Scott R; Morris, David M; Utter, Alan C

2013-05-01

The purpose of this study was to characterize the magnitude of acute weight gain (AWG) and dehydration in mixed martial arts (MMA) fighters before competition. Urinary measures of hydration status and body mass were determined approximately 24 hours before and then again approximately 2 hours before competition in 40 MMA fighters (mean ± SE, age: 25.2 ± 0.65 years, height: 1.77 ± 0.01 m, body mass: 75.8 ± 1.5 kg). The AWG was defined as the amount of body weight the fighters gained in the approximately 22-hour period between the official weigh-in and the actual competition. On average, the MMA fighters gained 3.40 ± 2.2 kg or 4.4% of their body weight in the approximately 22-hour period before competition. Urine specific gravity significantly decreased (p 1.021 immediately before competition indicating significant or serious dehydration. The MMA fighters undergo significant dehydration and fluctuations in body mass (4.4% avg.) in the 24-hour period before competition. Urinary measures of hydration status indicate that a significant proportion of MMA fighters are not successfully rehydrating before competition and subsequently are competing in a dehydrated state. Weight management guidelines to prevent acute dehydration in MMA fighters are warranted to prevent unnecessary adverse health events secondary to dehydration.

Vegetation greenness trend (2000 to 2009) and the climate controls in the Qinghai-Tibetan Plateau

Science.gov (United States)

Zhang, Li; Guo, Huadong; Ji, Lei; Lei, Liping; Wang, Cuizhen; Yan, Dongmei; Li, Bin; Li, Jing

2013-01-01

The Qinghai-Tibetan Plateau has been experiencing a distinct warming trend, and climate warming has a direct and quick impact on the alpine grassland ecosystem. We detected the greenness trend of the grasslands in the plateau using Moderate Resolution Imaging Spectroradiometer data from 2000 to 2009. Weather station data were used to explore the climatic drivers for vegetation greenness variations. The results demonstrated that the region-wide averaged normalized difference vegetation index (NDVI) increased at a rate of 0.036  yr−1. Approximately 20% of the vegetation areas, which were primarily located in the northeastern plateau, exhibited significant NDVI increase trend (p-value plateau. A strong positive relationship between NDVI and precipitation, especially in the northeastern plateau, suggested that precipitation was a favorable factor for the grassland NDVI. Negative correlations between NDVI and temperature, especially in the southern plateau, indicated that higher temperature adversely affected the grassland growth. Although a warming climate was expected to be beneficial to the vegetation growth in cold regions, the grasslands in the central and southwestern plateau showed a decrease in trends influenced by increased temperature coupled with decreased precipitation.

Pharmaceutical pricing: an empirical study of market competition in Chinese hospitals.

Science.gov (United States)

Wu, Jing; Xu, Judy; Liu, Gordon; Wu, Jiuhong

2014-03-01

High pharmaceutical prices and over-prescribing of high-priced pharmaceuticals in Chinese hospitals has long been criticized. Although policy makers have tried to address these issues, they have not yet found an effective balance between government regulation and market forces. Our objective was to explore the impact of market competition on pharmaceutical pricing under Chinese government regulation. Data from 11 public tertiary hospitals in three cities in China from 2002 to 2005 were used to explore the effect of generic and therapeutic competition on prices of antibiotics and cardiovascular products. A quasi-hedonic regression model was employed to estimate the impact of competition. The inputs to our model were specific attributes of the products and manufacturers, with the exception of competition variables. Our results suggest that pharmaceutical prices are inversely related to the number of generic and therapeutic competitors, but positively related to the number of therapeutic classes. In addition, the product prices of leading local manufacturers are not only significantly lower than those of global manufacturers, but are also lower than their non-leading counterparts when other product attributes are controlled for. Under the highly price-regulated market in China, competition from generic and therapeutic competitors did decrease pharmaceutical prices. Further research is needed to explore whether this competition increases consumer welfare in China's healthcare setting.

A very competitive oil

International Nuclear Information System (INIS)

Delamarche, Myrtille; Cahuzac, Adrien; Cognasse, Olivier; Dupin, Ludovic; Fleitour, Gaelle; James, Olivier; Stassi, Franck

2015-01-01

Drop in oil barrel prices results in 8 to 10 billions in savings for French companies, i.e. as much as the tax credit for competitiveness and employment. This article analyses how the different sectors take benefit of this saving due to lower oil prices. It outlines that this decrease has been very profitable for the refining sector which exhibited historic margins. As far as the chemistry sector is concerned, costs are reduced but profits are less important as this decrease compensates the decrease of the euro with respect to the dollar. The plastic industry does not take profit as it comes at the end of value chain where other actors already took their benefits. Therefore, there is no profit in agriculture as far as plastic products and fertilizers are concerned. On the opposite, the decrease of marine fuel has been profitable to the fishing sector as well as to the sea transport sector. As far as road transport is concerned the fuel price decrease is reflected in resale prices, and the oil price decrease had therefore no impact, or only for few days. It's not the case for air transport where companies took benefit of this decrease. In this respect, a second article outlines that airline companies have learned lessons from previous oil price counter-shock to adapt their strategies. The last article addresses the general situation of industry which exhibits a better financial health, could be boosted by a recovery of consumption. But growth is still to be confirmed by investments. A brief article notices that the profit is less important at the world level, i.e. more important in Europe than in Asia and even more than in Africa

Increased Intake of Selected Vegetables, Herbs and Fruit may Reduce Bone Turnover in Post-Menopausal Women

Directory of Open Access Journals (Sweden)

Caroline Ann Gunn

2015-04-01

Full Text Available Increased consumption of vegetables/herbs/fruit may reduce bone turnover and urinary calcium loss in post-menopausal women because of increased intake of polyphenols and potassium, but comparative human studies are lacking. The main aim was to compare bone turnover markers and urinary calcium excretion in two randomised groups (n = 50 of healthy post-menopausal women consuming ≥9 servings of different vegetables/herbs/fruit combinations (three months. Group A emphasised a generic range of vegetables/herbs/fruit, whereas Group B emphasised specific vegetables/herbs/fruit with bone resorption-inhibiting properties (Scarborough Fair Diet, with both diets controlled for potential renal acid load (PRAL. Group C consumed their usual diet. Plasma bone markers, urinary electrolytes (24 h and estimated dietary PRAL were assessed at baseline and 12 weeks. Procollagen type I N propeptide (PINP decreased (−3.2 μg/L, p < 0.01 in the B group only, as did C-terminal telopeptide of type I collagen (CTX (−0.065 μg/L, p < 0.01 in women with osteopenia compared to those with normal bone mineral density (BMD within this group. Intervention Groups A and B had decreased PRAL, increased urine pH and significantly decreased urinary calcium loss. Urinary potassium increased in all groups, reflecting a dietary change. In conclusion, Group B demonstrated positive changes in both turnover markers and calcium conservation.

Competition policy and environmental protection, obstacles to competition in the waste sector

International Nuclear Information System (INIS)

Alanen, J.; Marttinen, K.; Steiner, N.

2000-08-01

This study deals with the legal rules that affect the conditions of competition in the waste sector at both the EU level and national level in Finland. This study describes further, on a more general level, the relation between the EC's internal market rules and competition rules and the actions involving environmental protection taken by public authorities (EG, Member States) and enterprises. Hazardous waste is not studied in this report. The study comprises two parts: The first part deals with the free movement of waste, EG rules on the transportation of waste between Member States, and the specific EG rules and Finnish laws and regulations on waste. The aim of this study has been, on the one hand, to discuss cases where restrictions of competition in the waste sector are a direct consequence of EG rules on waste and, on the other hand, situations where EG rules or the large margin of manoeuvre left with the Member States create problems with a view to a well functioning competition at the national level. Part two deals with the application of EG rules and Finnish competition rules to companies' agreements on actions involving environmental protection and especially waste management, and to their operations in general and, in certain cases, also to the measures taken by Member States. The EG rules on waste do not pay enough attention to competition aspects. The different requirements set by Member States result in distortion of competition while the rules governing the shipments of waste are not effective enough. From the internal market point of view, more binding and detailed rules are motivated. Competition rules are fully applicable to enterprises' measures aimed at environmental protection that restrict competition. Environmental protection aspects in connection with a case-to-case consideration of interests is, however, gaining importance. Those restrictions of competition in the waste sector that EC has dealt with have without exception concerned the

Sterility and mating competitiveness of irradiated males of the large milkweed bug, Oncopeltus fasciatus

International Nuclear Information System (INIS)

Moursy, L.E.; Eesa, N.M.; Cutkomp, L.K.

1991-01-01

Low level gamma radiation adversely affected the reproductive capacity of the large milkweed bug, oncopeltus fasciatus dallas, as expressed by fecundity and fertility. Treatment was applied to late 5th instar male nymphs. Both fecundity and fertility decreased linearly with the treatment dose and complete sterility occurred when males were exposed to 6 kilorads and mated with normal females. The mating competitiveness of O. fasciatus males irradiated at late 5th instar nymphs decreased linearly with the treatment dose. A strong negative relationship existed between dose and mating competitiveness ( r = -0.93). A 3:2 ratio of irradiated males at 4 kilorads ( as late 5th instar as many progeny as normal in F 1 .2 tab.,1 fig

Occupancy of yellow-billed and Pacific loons: evidence for interspecific competition and habitat mediated co-occurrence

Science.gov (United States)

Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Wright, Kenneth G.; Uher-Koch, Brian D.; Rosenberger, Amanda E.

2014-01-01

Interspecific competition is an important process structuring ecological communities, however, it is difficult to observe in nature. We used an occupancy modelling approach to evaluate evidence of competition between yellow-billed (Gavia adamsii) and Pacific (G. pacifica) loons for nesting lakes on the Arctic Coastal Plain of Alaska. With multiple years of data and survey platforms, we estimated dynamic occupancy states (e.g. rates of colonization or extinction from individual lakes) and controlled for detection differences among aircraft platforms and ground survey crews. Results indicated that yellow-billed loons were strong competitors and negatively influenced the occupancy of Pacific loons by excluding them from potential breeding lakes. Pacific loon occupancy was conditional on the presence of yellow-billed loons, with Pacific loons having almost a tenfold decrease in occupancy probability when yellow-billed loons were present and a threefold decrease in colonization probability when yellow-billed loons were present in the current or previous year. Yellow-billed and Pacific loons co-occurred less than expected by chance except on very large lakes or lakes with convoluted shorelines; variables which may decrease the cost of maintaining a territory in the presence of the other species. These results imply the existence of interspecific competition between yellow-billed and Pacific loons for nesting lakes; however, habitat characteristics which facilitate visual and spatial separation of territories can reduce competitive interactions and promote species co-occurrence.

Changes in vegetation and soil seed bank of meadow after waterlogging caused by Castor fiber

Directory of Open Access Journals (Sweden)

Magdalena Franczak

2015-07-01

Full Text Available Soil waterlogging is among abiotic stresses that influence species composition and productivity in numerous plant communities. The aim of the study was to find answer to the question of how waterlogging caused by beavers’ activity induces quantitative and qualitative changes of vegetation and soil seed bank levels of variable-moist meadows. An immediate effect of the waterlogging at the level of vegetation was the decline in species richness and a decrease in the values of the biodiversity index. Water stress inhibited growth and development of plants already present and, primarily, impeded recruitment of new individuals of species characteristic of variable-moist meadows, e.g. Cirsium rivulare, Filipendula ulmaria and Lythrum salicaria, which were replaced by Carex acutiformis. Prolonged waterlogging did not induce equally substantial changes in the soil seed bank as in the vegetation. Both in the waterlogged and control patches, slightly decreased species richness and biodiversity index were recorded. After waterlogging withdrawal, the reserves of the soil seed bank were slightly higher than the initial values. The differences were not statistically significant. In the waterlogged patch, the qualitative floristic similarity between taxa identified in the soil seed bank and vegetation cover declined, which was evidenced by the value of Jaccard’s index decreasing from 0.46 to 0.36. A reverse relationship was found in control patch, where the value of the similarity index slightly increased from 0.41 to 0.48.

The positive influence of state agricultural marketing programs on adults' fruit and vegetable consumption.

Science.gov (United States)

Howlett, Elizabeth A; Burton, Scot; Newman, Christopher L; Faupel, Michel A

2012-01-01

To assess whether state-sponsored agricultural marketing programs had a positive influence on adult consumers' fruit and vegetable consumption. Differences in fruit and vegetable consumption between 2000 and 2005 in states that initiated marketing campaigns during this period and those that did not were examined. A representative sample (n  =  237,320) of adults aged 18 and older from states with and without marketing programs was used. The study used data from the 2000 and 2005 Behavioral Risk Factor Surveillance System. The number of fruit and vegetable servings per week and the percentage of respondents consuming five or more servings of fruits and vegetables per day were examined. Between-subjects analysis of variance and logistic regression. In the absence of a marketing campaign, there was a significant decrease in fruit and vegetable consumption between 2000 and 2005. In states with campaigns, consumption remained stable or increased. Marketing effects were stronger for women than for men. Conclusions . State-sponsored agricultural marketing programs had favorable effects on consumers' consumption of fruits and vegetables.

ECOLOGICAL CONTROL EQUIPMENT AND TECHNOLOGY OF UNDERWATER VEGETATION DEVELOPMENT

Directory of Open Access Journals (Sweden)

V. TITINSCHNEIDER

2008-10-01

Full Text Available The excess of aquatic submerse vegetation development carries to the reduction of the real rearing area for the piscicultural material from the production farms and allow nestling of the ichthyophages bird species that decrease the fish production. Aquatic submerse vegetation stumble the utilization of aquatic zones for recreation and also wright function of basins utilized for the electric energy production, of micro electricity works through obstruction of the dams grid. The control of the aquatic submerse vegetation development, for Myriophyllum verticillatum, Ceratophyllum submersum, Urticularia vulgaris, Potamogeton natans, Nimphoides peltata species it is accomplish through the removing of some parts of these, preferably with all the stump system. Usually, these its accomplish with the floating equipments fit up with the thermic engines and the propulsion and governating elements who have harm over the fish and some others aquatic organisms through the noise, the displacing a large quality of water caused of propulsion systems and through the noxes elimination (flue, carburant trails, etc.. These technologies reside from the evacuation of the aquatic submerse vegetation and the stump systems of these with the help of an adjustable rake, hang up from the coast by a rope, wrapped to a drummer, who is trained by a motto-propeller group with a small installed power.

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.

Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements.

Science.gov (United States)

Halvorsen, Bente Lise; Blomhoff, Rune

2011-01-01

There is convincing evidence that replacing dietary saturated fats with polyunsaturated fats (PUFA) decreases risk of cardiovascular diseases. Therefore, PUFA rich foods such as vegetable oils, fatty fish, and marine omega-3 supplements are recommended. However, PUFA are easily oxidizable and there is concern about possible negative health effects from intake of oxidized lipids. Little is known about the degree of lipid oxidation in such products. To assess the content of lipid oxidation products in a large selection of vegetable oils and marine omega-3 supplements available in Norway. Both fresh and heated vegetable oils were studied. A large selection of commercially available vegetable oils and marine omega-3 supplements was purchased from grocery stores, pharmacies, and health food stores in Norway. The content of lipid oxidation products were measured as peroxide value and alkenal concentration. Twelve different vegetable oils were heated for a temperature (225°C) and time (25 minutes) resembling conditions typically used during cooking. The peroxide values were in the range 1.04-10.38 meq/kg for omega-3 supplements and in the range 0.60-5.33 meq/kg for fresh vegetable oils. The concentration range of alkenals was 158.23-932.19 nmol/mL for omega-3 supplements and 33.24-119.04 nmol/mL for vegetable oils. After heating, a 2.9-11.2 fold increase in alkenal concentration was observed for vegetable oils. The contents of hydroperoxides and alkenals in omega-3 supplements are higher than in vegetable oils. After heating vegetable oils, a large increase in alkenal concentration was observed.

Competitive outcome of Daphnia-Simocephalus experimental microcosms: salinity versus priority effects.

Directory of Open Access Journals (Sweden)

Cláudia Loureiro

Full Text Available Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy alter the competitive outcome (measured as the rate of population biomass increase of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order. With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L(-1, crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa. At lower NaCl concentrations (0.00 and 0.75 g L(-1, Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L(-1 alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing and biodiversity.

Significant competitive advantage conferred by meiosis and syngamy in the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Birdsell, J; Wills, C

1996-01-01

The presumed advantages of genetic recombinations are difficult to demonstrate directly. To investigate the effects of recombination and background heterozygosity on competitive ability, we have performed serial-transfer competition experiments between isogenic sexual and asexual strains of the yeast Saccharomyces cerevisiae. The members of these diploid pairs of strains differed only in being heterozygous (sexual) or homozygous (asexual) at the mating type or MAT locus. Competing pairs had either a completely homozygous or a heterozygous genetic background, the latter being heterozygous at many different loci throughout the genome. A round of meiotic recombination (automixis) conferred a large and statistically significant enhancement of competitive ability on sexual strains with a heterozygous genetic background. By contrast, in homozygous background competitions, meiosis decreased the sexual strains' initial relative competitive ability. In all cases, however, the sexual strains outcompeted their isogenic asexual counterparts, whether meiotic recombination had occurred or not. In some genetic backgrounds, this was due in part to an overdominance effect on competitive advantage of heterozygosity at the MAT locus. The advantage of the sexual strains also increased significantly during the course of the homozygous background competitions, particularly when meiosis had occurred. This latter effect either did not occur or was very weak in heterozygous background competitions. Overall, sexual strains with heterozygous genetic backgrounds had a significantly higher initial relative competitive ability than those with homozygous backgrounds. The advantage of mating type heterozygosity in this organism extends far beyond the ability to recombine meiotically. PMID:8570658

Theoretical aspects of competitive advantage and competition

OpenAIRE

Hudakova, Ivana

2009-01-01

The concept of competitive advantage is well-known for many of us and a number of literary resources focused on entrepreneurship and functioning of economies deal with it, either directly or indirectly. The understanding of the term competitive advantage though sometimes varies. One can only perceive it when looking at it as a whole, a live organism that is constantly developing in a complex dynamic entrepreneurial environment, the individual parts of which do not function when separated from...

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

Directory of Open Access Journals (Sweden)

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

Field Evidence of Cadmium Phytoavailability Decreased Effectively by Rape Straw and/or Red Mud with Zinc Sulphate in a Cd-Contaminated Calcareous Soil

Science.gov (United States)

Li, Bo; Yang, Junxing; Wei, Dongpu; Chen, Shibao; Li, Jumei; Ma, Yibing

2014-01-01

To reduce Cd phytoavailability in calcareous soils, the effects of soil amendments of red mud, rape straw, and corn straw in combination with zinc fertilization on Cd extractability and phytoavailability to spinach, tomato, Chinese cabbage and radish were investigated in a calcareous soil with added Cd at 1.5 mg kg−1. The results showed that water soluble and exchangeable Cd in soils was significantly decreased by the amendments themselves from 26% to 70%, which resulted in marked decrease by approximately from 34% to 77% in Cd concentration in vegetables. The amendments plus Zn fertilization further decreased the Cd concentration in vegetables. Also cruciferous rape straw was more effective than gramineous corn straw. In all treatments, rape straw plus red mud combined with Zn fertilization was most effective in decreasing Cd phytoavailability in soils, and it is potential to be an efficient and cost-effective measure to ensure food safety for vegetable production in mildly Cd-contaminated calcareous soils. PMID:25303439

Field evidence of cadmium phytoavailability decreased effectively by rape straw and/or red mud with zinc sulphate in a Cd-contaminated calcareous soil.

Directory of Open Access Journals (Sweden)

Bo Li

Full Text Available To reduce Cd phytoavailability in calcareous soils, the effects of soil amendments of red mud, rape straw, and corn straw in combination with zinc fertilization on Cd extractability and phytoavailability to spinach, tomato, Chinese cabbage and radish were investigated in a calcareous soil with added Cd at 1.5 mg kg-1. The results showed that water soluble and exchangeable Cd in soils was significantly decreased by the amendments themselves from 26% to 70%, which resulted in marked decrease by approximately from 34% to 77% in Cd concentration in vegetables. The amendments plus Zn fertilization further decreased the Cd concentration in vegetables. Also cruciferous rape straw was more effective than gramineous corn straw. In all treatments, rape straw plus red mud combined with Zn fertilization was most effective in decreasing Cd phytoavailability in soils, and it is potential to be an efficient and cost-effective measure to ensure food safety for vegetable production in mildly Cd-contaminated calcareous soils.

Ireland's Competitiveness Challenge 2011

OpenAIRE

2012-01-01

The NCC publishes two annual competitiveness reports. Ireland's Competitiveness Challenge focuses on the national competitiveness issues of most importance to the enterprise sector and identifies policy recommendations required to address these issues. The report focuses on pursuing policies to improve competitiveness, particularly those to reduce the cost base for enterprise, to enhance the performance of the entire education system, and to deliver meaningful public sector reform. Ireland's ...

Ecophysiology of Trembling Aspen in Response to Root-Zone Conditions and Competition on Reclaimed Mine Soil.

Science.gov (United States)

Bockstette, S.; Landhäusser, S.; Pinno, B.; Dyck, M. F.

2014-12-01

Reclaimed soils are typically characterized by increased bulk densities, penetration resistances and poor soil structure as well as associated problems with hydrology and aeration. As a result, available rooting space for planted tree seedlings is often restricted to a shallow layer of topsoil, which is usually of higher quality and is cultivated prior to planting. This may hinder the development of healthy root systems, thus drastically increasing the risk for plant stress by limiting access to soil resources such as water, nutrients and oxygen. These problems are exacerbated when herbaceous plants compete for the same resources within this limited root-zone. To understand how limited rooting space affects the physiology of young trees, we experimentally manipulated soil conditions and levels of competition at a reclaimed mine site in central Alberta, Canada. The site was characterized by heavily compacted, fine textured subsoil (~2.0 Mg ha-1), capped with 15 cm of topsoil (~1.5 Mg ha-1). In a replicated study (n=6) half the plots were treated with a subsoil plow to a depth of about 60 cm to increase available rooting spece. Subsequently, trembling aspen (Populus tremuloides Michx.) and smooth brome (Bromus inermis L.) were planted to create four vegetation covers: aspen (a), brome (b), aspen + brome (ab) and control (c) (no vegetation). Various soil properties, including texture, bulk density, penetration resistance and water availability, in conjunction with plant parameters such as root and shoot growth, leaf area development, sap flow, and stomatal conductance have since been monitored, both in-situ and through destructive sampling. Our results indicate that the soil treatment was effective in lowering bulk densities and penetration resistance, while improving moisture retention characteristics. Tree seedling growth and leaf area development were significantly greater without competition, but did not differ between soil treatments. The soil treatment generally

Loss of competition in the outside host environment generates outbreaks of environmental opportunist pathogens.

Directory of Open Access Journals (Sweden)

Jani Anttila

Full Text Available Environmentally transmitted pathogens face ecological interactions (e.g., competition, predation, parasitism in the outside-host environment and host immune system during infection. Despite the ubiquitousness of environmental opportunist pathogens, traditional epidemiology focuses on obligatory pathogens incapable of environmental growth. Here we ask how competitive interactions in the outside-host environment affect the dynamics of an opportunist pathogen. We present a model coupling the classical SI and Lotka-Volterra competition models. In this model we compare a linear infectivity response and a sigmoidal infectivity response. An important assumption is that pathogen virulence is traded off with competitive ability in the environment. Removing this trade-off easily results in host extinction. The sigmoidal response is associated with catastrophic appearances of disease outbreaks when outside-host species richness, or overall competition pressure, decreases. This indicates that alleviating outside-host competition with antibacterial substances that also target the competitors can have unexpected outcomes by providing benefits for opportunist pathogens. These findings may help in developing alternative ways of controlling environmental opportunist pathogens.

Vegetables as a Source of Dietary Fiber to Prevent Degenerative Diseases

Directory of Open Access Journals (Sweden)

Deddy Muchtadi

2001-04-01

Full Text Available For long time vegetables were thought only as sources of several vitamins; however, it has been shown that vegetables contain other component, which is also important for maintaining body's health, i.e., dietary fiber. Dietary fiber is a group of polysaccharides oan other polymers, which cannot be digested by upper gastro-intestinal system of human. Dietary fiber can be grouped as soluble and insoluble dietary fiber, showing in different physiological effect. Soluble dietary fiber (SDF is effective in preventing cardiovascular disease, while insoluble dietary fiber (IDF can prevent the development of colon cancer, diverticulosis as well as obesity.Local vegetables found to contain high SDF (higher than 3,06% db are: watercress, green bean, carrot, eggplant, lettuce, broccoli, spinach, string bean, and aubergine; while which contain high IDF (higher than 40,60% db are: winged bean, watercress, chinese leaves, katuk leaves, lettuce, green bean, broccoli, carrot and spinach. Cooking (i.e. boiling, steaming and pan frying decrease the IDF content of vegetables, while their SDF content is not affected by cooking treatments.

Analyzing Sustainable Competitive Advantage: Strategically Managing Resource Allocations to Achieve Operational Competitiveness

Directory of Open Access Journals (Sweden)

Abdul Malek Nurul Aida

2015-12-01

Full Text Available In today’s dynamic business environment, a key challenge for all companies is to make adaptive adjustments to their manufacturing strategy. This study demonstrates the competitive priorities of manufacturing strategy in hydro-power case company to evaluate the level of sustainable competitive advantage and also to further analyze how business strategies are aligned with manufacturing strategies. This research is based on new holistic analytical evaluation of manufacturing strategy index, sense and respond, and sustainable competitive advantage models. These models help to describe, evaluate, and optimize resource allocation to meet the performance requirements in dynamic decision making. Furthermore, these models evaluate operational competitiveness for manufacturing strategies according to the multi-criteria priority. The results show that the adjustments of competitive priorities in manufacturing strategies by implementing the proposed holistic analytical models are helpful in strategically managing business operations. The discussion derives the most critical attributes in business operations while alignment of resource allocation with competitive priorities help to strategically focus those attributes. In conclusion, we argue that resource allocation and manufacturing strategies have become the most important capabilities in a business environment where companies focus to get a sustainable competitive advantage.

State of polyphenols in the drying process of fruits and vegetables.

Science.gov (United States)

McSweeney, M; Seetharaman, K

2015-01-01

This review presents an overview of drying technologies and its impact on the polyphenol content of vegetables and fruits. Polyphenols contribute to many health benefits and can act as antioxidants. Specifically an increased intake of polyphenols has been shown to decrease the incidence of cardiovascular disease; furthermore, it has been shown to help reduce the risk of neurodegenerative diseases in humans. Many researchers have reported on the effect of different drying techniques on the polyphenol content in fruits and vegetables. Polyphenol degradation mechanisms proposed in literature and pretreatments that potentially lead to higher retention of polyphenols during drying are also discussed.

Contamination pathways of spore-forming bacteria in a vegetable cannery.

Science.gov (United States)

Durand, Loïc; Planchon, Stella; Guinebretiere, Marie-Hélène; André, Stéphane; Carlin, Frédéric; Remize, Fabienne

2015-06-02

Spoilage of low-acid canned food during prolonged storage at high temperatures is caused by heat resistant thermophilic spores of strict or facultative bacteria. Here, we performed a bacterial survey over two consecutive years on the processing line of a French company manufacturing canned mixed green peas and carrots. In total, 341 samples were collected, including raw vegetables, green peas and carrots at different steps of processing, cover brine, and process environment samples. Thermophilic and highly-heat-resistant thermophilic spores growing anaerobically were counted. During vegetable preparation, anaerobic spore counts were significantly decreased, and tended to remain unchanged further downstream in the process. Large variation of spore levels in products immediately before the sterilization process could be explained by occasionally high spore levels on surfaces and in debris of vegetable combined with long residence times in conditions suitable for growth and sporulation. Vegetable processing was also associated with an increase in the prevalence of highly-heat-resistant species, probably due to cross-contamination of peas via blanching water. Geobacillus stearothermophilus M13-PCR genotypic profiling on 112 isolates determined 23 profile-types and confirmed process-driven cross-contamination. Taken together, these findings clarify the scheme of contamination pathway by thermophilic spore-forming bacteria in a vegetable cannery. Copyright © 2015 Elsevier B.V. All rights reserved.

Competitive differentiation through brand extensions in the era of hyper competition

Directory of Open Access Journals (Sweden)

Claudiu-Catalin Munteanu

2015-03-01

Full Text Available In the era of hyper competition, competitive differentiation has become increasingly important. Brand extensions are used by companies across various industries for competitive differentiation. But in the era of hyper competition, a successful differentiation strategy requires that a brand emphasizes on uniqueness rather than commoditization. In this article, we make a case for creating a meaningful differentiation strategy. We emphasize the role of brand extensions for competitive differentiation and highlight the main perils of using brand extensions as a primary differentiation strategy. By using qualitative research, we identify primary objectives for brand extensions in practice. This investigation uses in-depth interviews with 14 senior brand managers across various industries to highlight brand portfolio strategies in relation to the brand differentiation strategy. Findings reveal that for business at the base of the pyramid, in markets such as Romania, brand managers are using brand extensions to increase sales or to boost short-term revenue rather than to implement a coherent differentiation strategy. We conclude with multiple recommendations for improving brand extension usage as a strategic instrument for creating meaningful differentiation in the era of hyper competition.

Getting Competitive: Competitive Intelligence Is a Smart next Step for Information Pros

Science.gov (United States)

Correia, Cynthia Cheng

2006-01-01

Competitive Intelligence (CI) has become an attractive concept for Library and Information Science professionals, as information and research functions have become commoditized by end users, and financial, competitive, and performance pressures increase the need to demonstrate value. In the current competitive and cost-cutting environment,…

The role of vegetation dynamics in the control of atmospheric CO{sub 2} content

Energy Technology Data Exchange (ETDEWEB)

Sitch, Stephen

2000-04-01

This thesis contains a description of the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ-DGVM) and its application to infer the role of vegetation dynamics on atmospheric CO{sub 2} content at different time-scales. The model combines vegetation dynamics and biogeochemistry in a modular framework. Individual modules describe ecosystems processes, including vegetation resource competition and production, tissue turnover, growth, fire and mortality, soil and litter biogeochemistry, including the effects of CO{sub 2} on these processes. The model simulates realistic post-disturbance succession in different environments. Seasonal exchange of H{sub 2}O and CO{sub 2} between the terrestrial biosphere and the atmosphere is modelled in reasonable agreement with observation. Global estimates of carbon stocks in soil, litter and vegetation are within their acceptable ranges and the model captures the present-day patterns in vegetation. Fire return intervals are simulated correctly in most regions. Results emphasise the important role of the terrestrial biosphere in both the seasonal cycle and in the inter-annual variability in the growth rate of atmospheric CO{sub 2}. LPJ successfully reproduced both the amplitude and phase of the seasonal cycle of atmospheric CO{sub 2} content as measured at a global network of monitoring stations. The model predicted a small net terrestrial biosphere uptake of CO{sub 2} during the 1980s with a strong CO{sub 2} fertilisation effect, which enhances plant production, reduced by the effects of climate and land use change. Historical land use change and CO{sub 2} fertilisation have been the dominant, albeit opposing factors governing the response of the terrestrial biosphere with respect to carbon storage during the 20th century. LPJ is run using one future climate and atmospheric CO{sub 2} scenario until 2200. Enhanced production due to the CO{sub 2} fertilisation effect eventually reaches an asymptote, and consequently the ability of