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Sample records for optimum plant population

  1. Optimum Stratification of a Skewed Population

    OpenAIRE

    D.K. Rao; M.G.M. Khan; K.G. Reddy

    2014-01-01

    The focus of this paper is to develop a technique of solving a combined problem of determining Optimum Strata Boundaries(OSB) and Optimum Sample Size (OSS) of each stratum, when the population understudy isskewed and the study variable has a Pareto frequency distribution. The problem of determining the OSB isformulated as a Mathematical Programming Problem (MPP) which is then solved by dynamic programming technique. A numerical example is presented to illustrate the compu...

  2. Optimum heat storage design for heat integrated multipurpose batch plants

    CSIR Research Space (South Africa)

    Stamp, J

    2011-01-01

    Full Text Available procedure is presented tha journal homepage: www All rights reserved. ajozi T, Optimum heat storage grated multipurpose batch plants , South Africa y usage in multipurpose batch plants has been in published literature most present methods, time... � 2pL?u?kins ? 1 h3A3?u?cu?U (36) The internal area for heat loss by convection from the heat transfer medium is given by Constraint (37) and the area for convective heat transfer losses to the environment is given in Constraint (38). A1?u? ? 2...

  3. Optimum gas turbine cycle for combined cycle power plant

    International Nuclear Information System (INIS)

    Polyzakis, A.L.; Koroneos, C.; Xydis, G.

    2008-01-01

    The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power

  4. Populations in clonal plants

    Directory of Open Access Journals (Sweden)

    Jussi Tammisola

    1986-12-01

    Full Text Available Population phenomena in higher plants are reviewed critically, particularly in relation to clonality. An array of concepts used in the field are discussed. In contrast to animals, higher plants are modular in structure. Plant populations show hierarchy at two levels: ramets and genets. In addition, their demography is far more complicated, since even the direction of development of a ramet may change by rejuvenation. Therefore, formulae concerning animal populations often require modification for plants. Furthermore, at the zygotic stage, higher plants are generally less mobile than animals. Accordingly, their population processes tend to be more local. Most populations of plants have a genetic structure: alleles and genotypes are spatially aggregated. Due to the short-ranged foraging behaviour of pollinators, genetically non-random pollination prevails. A generalized formula for parent-offspring dispersal variance is derived. It is used to analyze the effect of clonality on genetic patchiness in populations. In self-compatible species, an increase in clonality will tend to increase the degree of patchiness, while in self-incompatible species a decrease may result. Examples of population structure studies in different species are presented. A considerable degree of genetic variation appears to be found also in the populations of species with a strong allocation of resources to clonal growth or apomictic seed production. Some consequences of clonality are considered from the point of view of genetic conservation and plant breeding.

  5. Optimum size determination of nuclear dual-purpose desalination plants

    International Nuclear Information System (INIS)

    Gaussens, J.

    1966-01-01

    The economics of dual-purpose desalination plants is presented from a general standpoint. The concept of demand curves for water and electricity is introduced, which leads to a rational sharing of production costs between both commodities within the framework of a market. The purpose of the study, which is based upon the principles of classical economics, is to develop objective criteria for the design of desalination plants and to derive from these a normative method for pricing both joint products, water and electricity, following as much as possible the structure of the demand. Such criteria are in particular either the maximization of benefit for the operator or the maximum welfare for the community. They involve either equality between marginal costs and revenues, or equality between marginal costs and marginal satisfactions (theory of surplus). As the size of the plant is often the predominant factor in selecting the process to be used, it follows from the above considerations that this selection is closely related to: (a) The shape of the demand curve for water; (b) The economic criterion selected and the relevant constraints (public or private ownership, limitation of the investments, etc). This makes market surveys and a rather refined economic analysis indispensable before any decision is taken on the desalination technique to be adopted. (author). Abstract only

  6. An evaluation of the optimum timing for planting short rotation coppice

    Energy Technology Data Exchange (ETDEWEB)

    Turnbull, D.J.; Jefferies, R.; Parfitt, R.

    2004-07-01

    This report summarises the results of a project to determine the optimum timing for planting, evaluate problems due to late planting in the spring, and to study the planting of willows at different times during the autumn. Details are given of the site installation, previous research on the effect of planting date and storage, and assessment of the establishment and biomass productivity and the viability of cuttings in long-term storage. Charts illustrating biomass productivity are presented, and long-term storage of willow cuttings for autumn planting is discussed.

  7. Urban Optimum Population Size and Development Pattern Based on Ecological Footprint Model: Case of Zhoushan, China

    Directory of Open Access Journals (Sweden)

    Yuan LU

    2016-09-01

    Full Text Available The agglomeration of population in the city can reflect the prosperity in the economy, society and culture. However, it has also brought a series of problems like environmental pollution, traffic congestion, housing shortage and jobs crisis. The results can be shown as the failure of urban comprehensive function, the decline of city benefits, and the contradiction between socioeconomic circumstance and ecosystem. Therefore, a reasonable population capacity, which is influenced by ecological resources, urban environment, geographical elements, social and economic factors, etc., is objectively needed. How to deal with the relationship between the utilization of natural capital and development of the city is extremely essential. This paper takes Zhoushan Island as an example, which is the fourth largest island off the coast of China. Firstly, the interactively influencing factors of urban optimal population are illustrated. And method is chosen to study the optimal population size. Secondly, based on the model of ecological footprint (EP, the paper calculates and analyzes the ecological footprint and ecological capacity of the Zhoushan Island, in order to explore the optimal population size of the city. Thirdly, analysis and evaluation of the resources and urban environment carrying capacity is made. Finally, the solution of the existing population problems and the suggestion for the future development pattern of the city are proposed in the urban eco-planning of Zhoushan Island. The main strategies can be summarized in two aspects: one is to reduce the ecological footprint, the other is to increase the ecological supply. The conclusion is that the current population of Zhoushan Island is far beyond the optimum population size calculated by the ecological footprint model. Therefore, sustainable development should be the guidance for urban planning in Zhoushan Island, and a low-carbon development pattern for the city is advocated.

  8. Solar assisted biogas plants: Pt. 4. Optimum area for blackening and double glazing over a fixed-dome biogas plant

    Energy Technology Data Exchange (ETDEWEB)

    Jayashankar, B.C.; Kishor, J.; Goyal, I.C.; Sawhney, R.L.; Sodha, M.S.

    The economic analysis of a fixed-dome biogas plant of rated capacity 8 m/sup 3/, above which a part of the ground is blackened and doubly glazed in the cold climate of Srinagar is presented. Blackening and glazing of the ground cannot alone maintain the slurry temperature at 35/sup 0/C, which is the optimum temperature in the mesophilic range for the anaerobic digestion of cattle dung, and so a part of the biogas must be burnt. The electrical simulation experiments have been performed to determine the loss or gain of heat from the underground biodigestor to the ambient atmosphere through the ground if a part of the ground above is blackened and double glazed. Economic analysis of the system shows that the optimum area to be blackened and glazed would have a radius 1.5 times that of the biodigestor.

  9. Temperature optimum of algae living in the outfall of a power plant on Lake Monona

    International Nuclear Information System (INIS)

    Brock, T.D.; Hoffmann, J.

    1974-01-01

    Temperature optima for photosynthesis were measured for algal populations living in the outfall of a fossil-fuel electric power plant on Lake Monona and were compared with the temperature optima of algae living in a control area in the nearby Yahara River. The temperature of the power plant outfall averaged about 8 0 C higher than that of the Yahara River. In the winter, no differences in species composition between the two study areas could be detected, Cladophora and Ulothrix being the dominant algae. The temperature optima of the populations from the two locations were the same, around 27 0 C, although the habitat temperatures at both locations were considerably lower. The only difference in response to temperature seen between the two populations was that the population at the outfall was able to photosynthesize at higher temperature, still showing high photosynthesis at 35 0 C and detectable photosynthesis at 46 0 C, a temperature at which the population from the Yahara River showed no detectable photosynthesis. In the summer, the dominant algae at the power plant outfall were Stigeoclonium and filamentous blue-green algae (family Oscillatoriaceae), whereas at the Yahara River the algal population was almost exclusively Cladophora. The temperature optima of both summer populations were the same, 31.5 0 C, only slightly higher than the mid-winter optima. Again, the population from the power plant was able to photosynthesize at higher temperature than the control population, showing quite active photosynthesis at 42.5 0 C, a temperature at which the population from the Yahara River was completely inactive. (U.S.)

  10. Analysis of near optimum design for small and medium size nuclear power plants

    International Nuclear Information System (INIS)

    Ahmed, A.A.

    1977-01-01

    Market surveys in recent years have shown that a significant market would exist among the developing nations of the world for nuclear power plants that would be classified as small to medium sized, provided that these small plants could produce electricity at a unit price comparable to that of equivalent sized fossil fired plants. Nuclear plants in the range of 100 MWe to 500 MWe would fit more effectively into the relatively smaller grids of most developing nations than would the 900 MWe to 1300 MWe units now being constructed in the large industrial nations. Worldwide re-evaluation of the worth of fossil fuels has prompted a re-examination of the competitive position of small to medium sized nuclear generating units compared to comparable fossil fired units, especially in the context of units specifically optimized for the size range of interest, rather than of designs that are simply scaled down versions of the currently available larger units. Since the absolute cost of electricity is more sensitive to external factors such as cost of money, national inflation rate and time required for licensing and construction than to details of design or perhaps even to choice of fuels, and since the cost of electricity generated in small to medium sized fossil fired units is periodically compared to that of scaled down versions of conventional large nuclear units, the point of view taken here is one of comparing the relative generating costs of smaller nuclear units of optimum design with the corresponding costs of scaled down versions of current large nuclear generating units

  11. Analysis of supply chain, scale factor, and optimum plant capacity for the production of ethanol from corn stover

    International Nuclear Information System (INIS)

    Leboreiro, Jose; Hilaly, Ahmad K.

    2013-01-01

    A detailed model is used to perform a thorough analysis on ethanol production from corn stover via the dilute acid process. The biomass supply chain cost model accounts for all steps needed to source corn stover including collection, transportation, and storage. The manufacturing cost model is based on work done at NREL; attainable conversions of key process parameters are used to calculate production cost. The choice of capital investment scaling function and scaling parameter has a significant impact on the optimum plant capacity. For the widely used exponential function, the scaling factors are functions of plant capacity. The pre-exponential factor decreases with increasing plant capacity while the exponential factor increases as the plant capacity increases. The use of scaling parameters calculated for small plant capacities leads to falsely large optimum plants; data from a wide range of plant capacities is required to produce accurate results. A mathematical expression to scale capital investment for fermentation-based biorefineries is proposed which accounts for the linear scaling behavior of bio-reactors (such as saccharification vessels and fermentors) as well as the exponential nature of all other plant equipment. Ignoring the linear scaling behavior of bio-reactors leads to artificially large optimum plant capacities. The minimum production cost is found to be in the range of 789–830 $ m −3 which is significantly higher than previously reported. Optimum plant capacities are in the range of 5750–9850 Mg d −1 . The optimum plant capacity and production cost are highly sensitive to farmer participation in biomass harvest for low participation rates. -- Highlights: •A detailed model is used to perform a technoeconomic analysis for the production of ethanol from corn stover. •The capital investment scaling factors were found to be a function of plant capacity. •Bio-reactors (such as saccharification vessels and fermentors) in large size

  12. Computerized optimum distribution of loads among the turbogenerators of fossil-fuel electric power plants

    Energy Technology Data Exchange (ETDEWEB)

    Foshko, L S; Zusmanovich, L B; Flos, S L; Pal' chik, V A; Konevskii, B I

    1979-04-01

    The problem of determining the optimum distribution of loads among turbogenerators in a fossil-fuel power plant is considered based on satisfying the following requirements: distribution of electrical and thermal loads to minimize the heat expended on the turbine unit; calculation based on turbogenerator characteristics that most completely describe operating conditions; no constraints on the configuration of turbogenerator performance characteristics; calculation of load distribution based on net characteristics including the internal needs of the turbogenerators; consideration of all operational limitations in turbogenerator working conditions; results should be applicable to any predetermined differential of the load change. A flowchart is given showing the organization of the Optim-76 program complex for solution of this problem. An example is given showing application of the Optim-76 program implemented by a Minsk-32 computer in the case of a heat and electric power station with three turbogenerators. The results show that a dynamic programming method has considerable advantages for this applicaton on third-generation computers.

  13. Effect of Plant and Row Spacing on the Yield and Oil Contents of ...

    African Journals Online (AJOL)

    Key words: Castor, Plant spacing, row spacing, seed yield. Introduction ... optimum plant population, fertilizer, quality seed, weeding practices, optimum plant ... 30 000 plants/ha for crops grown in the 750 to 900 mm rain fall is optimum. He.

  14. Investigations on the optimum design of chemical addition system for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Byong Hoon [Junior College of Inchon, Inchon (Korea, Republic of); Chung, Chang Kyu; Choi, Han Rim; Kim, Eun Kee; Ro, Tae Sun [Korea Power Engineering Company, Inc. Taejon (Korea, Republic of)

    1997-12-31

    Mixing characteristics of the chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5 and 6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet. 10 refs., 4 figs. (Author)

  15. Investigations on the optimum design of chemical addition system for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Byong Hoon [Junior College of Inchon, Inchon (Korea, Republic of); Chung, Chang Kyu; Choi, Han Rim; Kim, Eun Kee; Ro, Tae Sun [Korea Power Engineering Company, Inc. Taejon (Korea, Republic of)

    1998-12-31

    Mixing characteristics of the chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5 and 6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet. 10 refs., 4 figs. (Author)

  16. Method for determining the optimum mode of operation of the chemical water regime in the water-steam-circuit of power plants

    International Nuclear Information System (INIS)

    Sommerfeldt, P.; Reisner, H.; Hartmann, G.; Kulicke, P.

    1988-01-01

    The method aims at increasing the lifetime of secondary coolant circuit components in nuclear power plants through the determination of the optimum mode of operation of the chemical water regime by help of radioisotopes

  17. Optimum design for effective water transport through a double-layered porous hydrogel inspired by plant leaves

    Science.gov (United States)

    Kim, Hyejeong; Kim, Hyeonjeong; Huh, Hyungkyu; Hwang, Hyung Ju; Lee, Sang Joon

    2014-11-01

    Plant leaves are generally known to have optimized morphological structure in response to environmental changes for efficient water usage. However, the advantageous features of plant leaves are not fully utilized in engineering fields yet, since the optimum design in internal structure of plant leaves is unclear. In this study, the tissue organization of the hydraulic pathways inside plant leaves was investigated. Water transport through double-layered porous hydrogel models analogous to mesophyll cells was experimentally observed. In addition, computational experiment and theoretical analysis were applied to the model systems to find the optimal design for efficient water transport. As a result, the models with lower porosity or with pores distributed widely in the structure exhibit efficient mass transport. Our theoretical prediction supports that structural features of plant leaves guarantee sufficient water supply as survival strategy. This study may provide a new framework for investigating the biophysical principles governing the morphological optimization of plant leaves and for designing microfluidic devices to enhance mass transport ability. This study was supported by the National Research Foundation of Korea and funded by the Korean government.

  18. Optimum voltage of auxiliary systems for thermal and nuclear power plants

    International Nuclear Information System (INIS)

    Tokumitsu, Iwao; Segawa, Motomichi

    1979-01-01

    In the power plants in Japan, their unit power output has been greatly enhanced since the introduction of new powerful thermal power plants from 1950's to 1960's. In both thermal and nuclear power plants, 1,000 MW machines have been already in operation. The increase of unit power output results in the increase of in-plant load capacity. Of these the voltage adopted for in-plant low voltage systems is now mainly 440 V at load terminals, and the voltage for in-plant high voltage systems has been changing to 6 kV level via 3 kV and 4 kV levels. As plant capacity increases, the load of low voltage systems significantly increases, and it is required to raise the voltage of 400 V level. By the way, the low voltage in AC is specified to be not higher than 600 V. This makes the change within the above range comparatively easy. Considering these conditions, it is recommended to change the voltage for low voltage systems to 575 V at power source terminals and 550 V at load terminals. Some merits in constructing power systems and in economy by raising the voltage were examined. Though demerits are also found, they are only about 15% of total merits. The most advantageous point in raising the voltage is to be capable of increasing the supplying range to low voltage system loads. (Wakatsuki, Y.)

  19. Identification of optimum outfall location for desalination plant in the coastal waters off Tuticorin, India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; NaveenKumar, K.R.; Muraleedharan, K.R.

    Behaviour of the dilution characteristics of the coastal waters off Tuticorin is presented in the background of setting up of a desalination plant. Simulations of dispersion and spreading of the proposed discharges has been carried out. Scenarios...

  20. Development of a model to select plants with optimum metal phytoextraction potential.

    Science.gov (United States)

    Guala, Sebastián D; Vega, Flora A; Covelo, Emma F

    2011-07-01

    The aim of the present study is to propose a nonlinear model which provides an indicator for the maximum phytoextraction of metals to help in the decision-making process. Research into different species and strategies plays an important role in the application of phytoextraction techniques to the remediation of contaminated soil. Also, the convenience of species according to their biomass and pollutant accumulation capacities has gained important space in discussions regarding remediation strategies, whether to choose species with low accumulation capacities and high biomass or high accumulation capacities with low biomass. The effects of heavy metals in soil on plant growth are studied by means of a nonlinear interaction model which relates the dynamics of the uptake of heavy metals by plants to heavy metal deposed in soil. The model, presented theoretically, provides an indicator for the maximum phytoextraction of metals which depends on adjustable parameters of both the plant and the environmental conditions. Finally, in order to clarify its applicability, a series of experimental results found in the literature are presented to show how the model performs consistently with real data. The inhibition of plant growth due to heavy metal concentration can be predicted by a simple kinetic model. The model proposed in this study makes it possible to characterize the nonlinear behaviour of the soil-plant interaction with heavy metal pollution in order to establish maximum uptake values for heavy metals in the harvestable part of plants.

  1. Determination of the optimum design through different funding scenarios for future parabolic trough solar power plant in Algeria

    International Nuclear Information System (INIS)

    Trad, Ameur; Ait Ali, Mohand Ameziane

    2015-01-01

    Highlights: • Seven technical design options have been simulated. • The integration of auxiliary heating and TES stabilize electricity generation. • Impact of TES on the technical and economic performance of PTSPP projects. • Different funding scenarios to assess the profitability of CSP plant. • Sensitivity analysis plays an important role in building energy analysis. - Abstract: The purpose of this study is to determine an optimum design for a projected parabolic trough solar power plant (PTSPP) under Algerian climate through different funding scenarios. In this paper, seven different (d1–d7) designs for PTSPP have been developed for the Naâma site. Plant size, technology type, storage capacity, location of the plant, Operation and Maintenance (O and M) costs, replacement costs, fuel consumption, net CO 2 emission, levelized electricity cost, net power generation, specific investment costs and discount rate are the basis factors to determine the optimum sustainable design for PTSPP. The most attractive designs of each base technology were selected as D1, D2 and D3. The preferable design of three funding scenarios was finally selected on economic, financial and sensitivity analysis. It is finally concluded that, under the most favorable economic conditions allowed in this study, design D3 is the most advantageous in terms of benefit to cost ratio: its power output will be 100 MW el with 8 full load hours thermal energy storage. It was also found that for design D3 under funding scenario S2, the project will require an upfront grant of 396 MEUR. This corresponds to around 56% of the total investment cost and the payback period will be approximately 7 years

  2. The Hawkesbury-Nepean region: has the optimum population size been exceeded?

    Science.gov (United States)

    Jones, A; Pearson, B

    1995-01-01

    The Australian Federal Government has not included population size as an intersectoral component of the environmentally sustainable development process. The aim of this article is to show how water quality is a key indicator of environmental degradation and of declines in the quality of life. This study is an analysis of the environmental impacts of population on the Hawkesbury-Nepean River System and of the costs involved in change. Environmental degradation is viewed as the result of population size, per capita consumption, the quality of technology, and the organization of space and technology. The quantity and quality of freshwater systems are considered to be useful indicators of environmental degradation over large spatial areas because the impacts are associated with both land and water environments. The catchment area of this river system covers about 231,730 sq. km (68% bushland, 5% urban, 25% agricultural, and 0.1% industrial). About 45% of the land area is protected due to six dams, which provide 98% of water used in Sydney, Illawarra, and the Blue Mountains. Estimated population usage is 600,000-700,000 people. River flows are modified by dams, sewage discharges, water abstractions, and urban run-off from development. River use includes tourism, fishing, and recreation. The system suffers from severe eutrophication, bacterial contamination, toxic pollution, and hypoxia. The conclusion was reached after many years of concern that large-scale development should be deferred. However, housing plans continue for a 70% population increase by 2008. Sewage treatment improvements are costly. Alternatives are re-use of effluents ($2.5-3.5 billion for nonpotable use and $4-4.5 billion for potable use), diversion to the ocean ($3 billion), zero river discharge ($8400 per property for installation and $700 per annum maintenance), or inland disposal ($19 billion). Environmental protection efforts are also costly: $45 million worth of water for flushing away an algal

  3. Optimum power yield for bio fuel fired combined heat and power plants

    Energy Technology Data Exchange (ETDEWEB)

    Broden, Henrik; Nystroem, Olle; Joensson, Mikael

    2012-05-15

    Plant owners, suppliers, research institutions, industry representatives and (supporting) authorities are continuing to question the viability of what can be expected by increasing the steam data and the efficiency of cogeneration plants. In recent years, the overall conditions for investment in CHP have changed. Today, there is access to new materials that allow for more advanced steam data while maintaining availability. Although the financial environment with rising prices of electricity, heating and fuel along with the introduction of energy certificates and the interest in broadening the base of fuel has changed the situation. At the same time as the increased interest in renewable energy production creates competition among energy enterprises to find suppliers, increased prices for materials and labor costs have also resulted in increased investment and maintenance costs. Research on advanced steam data for biomass-fired power cogeneration plants has mainly emphasized on technical aspects of material selection and corrosion mechanisms based on performance at 100 % load looking at single years. Reporting has rarely been dealing with the overall economic perspective based on profitability of the CHP installations throughout their entire depreciation period. In the present report studies have been performed on how the choice of steam data affects the performance and economy in biomass-fired cogeneration plants with boilers of drum type and capacities at 30, 80 and 160 MWth with varied steam data and different feed water system configurations. Profitability is assessed on the basis of internal rate of return (IRR) throughout the amortization period of the plants. In addition, sensitivity analyses based on the most essential parameters have been carried out. The target group for the project is plant owners, contractors, research institutions, industry representatives, (supporting) authorities and others who are faced with concerns regarding the viability of what

  4. Optimum Vegetation Conditions for Successful Establishment of Planted Eastern White Pine (Pinus strobus L.

    Directory of Open Access Journals (Sweden)

    Douglas G. Pitt

    2016-08-01

    Full Text Available The 10th-growing season performance of planted eastern white pine (Pinus strobus L. seedlings was evaluated in response to herbaceous and woody vegetation control treatments within a clearcut and two variants of the uniform shelterwood regeneration system (single vs. multiple future removal cuts. Herbaceous vegetation control involved the suppression of grasses, forbs, ferns and low shrubs for the first 2 or 4 growing seasons after planting. Deciduous woody vegetation control treatments, conducted in combination with the herbaceous treatments within a response-surface design, involved the permanent removal of all tall shrubs and deciduous trees at the time of planting, at the end of the 2nd or 5th growing seasons, or not at all. In general, the average size of planted pine was related positively to the duration of herbaceous vegetation control and negatively to delays in woody control. White pine weevil (Pissodes strobi Peck altered these trends, reducing the height of pine on plots with little or no overtopping deciduous woody vegetation or mature tree cover. Where natural pine regeneration occurred on these plots, growth was similar but subordinate to the planted pine. Data from the three sites indicate that at least 60% of planted pine may be expected to reach an age-10 height target of 2.5 m when overtopping cover (residual overstory + regenerating deciduous is managed at approximately 65% ± 10%, and total herbaceous cover is suppressed to levels not exceeding 50% in the first five years. On productive sites, this combination may be difficult to achieve in a clearcut, and requires fairly rigorous vegetation management in shelterwood regeneration systems. Currently, synthetic herbicides offer the only affordable and effective means of achieving such vegetation control.

  5. DETERMINING MONOFILAMENT GILLNET OPTIMUM MESH SIZE TO MITIGATE Amphilophus citrinellus POPULATION OUTBREAKS IN IR.H.DJUANDA RESERVOIR

    Directory of Open Access Journals (Sweden)

    Prawira A.R.P. Tampubolon

    2015-12-01

    Full Text Available Gillnet is the most common fishing gear used by fishers in Ir. H. Djuanda Reservoir. Currently, gillnet catches are dominated by midas cichlid (Amphilophus citrinellus which is not the main target catch. To some extent, their presence is even considered intrusive by the fishers. The aim of this study is to reveal the optimum gillnet mesh size in catching this alien species, which in turn can be useful to control the fish population in Ir. H. Djuanda Reservoir. The study was conducted from August 2011 to January 2012. The mesh size of the gillnets were 1, 1.5, 2, 2.5, 3, and 3.5 inches. The total midas cichlid caught were 628 fish which were mostly caught in 1.5 inches sized gillnet. Length first mature fish is 13.31 cm. The optimum size of fish caught in the mesh of 1.5, 2, 2.5, 3, and 3.5 inches are 9.7, 12.9, 16.2, 19.4, and 22.6 cm, respectively.

  6. Developing the optimum boiler water and feedwater treatment for fossil plants

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, B [Electric Power Research Inst., Palo Alto, California (United States)

    1996-12-01

    Over the last two years a new set of cycle chemistry guidelines has been developed for each of the treatments used in fossil plants. These revisions have been based on research conducted over the last ten years, much at the international collaborative level. By careful selection and optimization of the boiler water and feedwater treatments, it will be possible to accrue large financial, maintenance, availability and performance improvements. (au) 14 refs.

  7. Ways to achieve optimum utilization of waste gas heat in cement kiln plants with cyclone preheaters

    Energy Technology Data Exchange (ETDEWEB)

    Steinbiss, E

    1986-02-01

    Kiln exit gases and the exhaust gases from clinker coolers often cannot be fully utilized in drying plants. In such cases a part of the heat content of the gases should be utilized for water heating. In addition, it is possible to utilize the waste gas heat in conventional steam boilers, with which, depending on design, it is possible to generate electricity at a rate of between 10-30 kWh/t (net output). A new and promising method of utilization of waste gas heat is provided by precalcining systems with bypass, in which up to 100% of the kiln exit gases can be economically bypassed and be utilized in a steam boiler, without requiring any cooling. A development project, already started, gives information on the operational behaviour of such a plant and on the maximum energy recoverable. Alternatively, the bypass gases may, after partial cooling with air or preheater exit gas, be dedusted and then utilized in a grinding/drying plant. Furthermore, they can be used in the cement grinding process for the drying of wet granulated blastfurnace slag or other materials. For this it is not necessary to dedust the bypass gases.

  8. Nuclear power plants in populated areas

    International Nuclear Information System (INIS)

    Wachsmann, F.

    1973-01-01

    The article first deals with the permanently increasing demand for electical power. Considering the ever growing energy demand which can no longer be covered by conventional power plants, it has become necessary to set up nuclear power plants of larger range. The author presents in a survey the basic function of nuclear power plants as well as the resulting risks and safety measures. The author concludes that according to present knowledge there is no more need to erect nuclear power plants outside densely populated urban areas but there is now the possibility of erecting nuclear power plants in densely populated areas. (orig./LH) [de

  9. Selection experiments for the optimum combination of AMF-plant-substrate for the restoration of coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Li-ping Wang; Wei-wei Zhang; Guang-xia Guo; Kui-mei Qian; Xiao-pei Huang [China University of Mining & Technology, Xuzhou (China). School of Environment and Spatial Informatics

    2009-07-15

    A complex substrate consisting of fly ash, coal gangue and excess sludge was used as an experimental soil in pot culture experiments. Different soil compositions were tested by observing the growth of arbuscular mycorrhizal (AM) fungi inoculated white clover, rye grass or corn. The biomass of the host plants, the mycorrhizal colonization (MC) rate and the mycorrhizal dependency (MD) were measured. The research addresses the preferable AMF-plant-substrate combination appropriate for restoration of coal mines. We used two inoculation methods: single-inoculation with Glomus versiforme or Glomus mosseae and a dual inoculation with both G.v and G.m. The results show that G.m is the preferable fungi and that dual inoculation does not show advantages for the restoration of coal mines. White clover inoculated with AM fungi is the most suitable condition for restoration of coal mines. The best weight ratio of fly ash, coal gangue and excess sludge was found to be 20:60:20. The optimum treatment conditions of AMF-plant-activated-substrate are described. 10 refs., 2 figs., 4 tabs.

  10. Technique for Selecting Optimum Fan Compression Ratio based on the Effective Power Plant Parameters

    Directory of Open Access Journals (Sweden)

    I. I. Kondrashov

    2016-01-01

    Full Text Available Nowadays, civilian aircrafts occupy the major share of global aviation industry market. As to medium and long - haul aircrafts, turbofans with separate exhaust streams are widely used. Here, fuel efficiency is the main criterion of this engine. The paper presents the research results of the mutual influence of fan pressure ratio and bypass ratio on the effective specific fuel consumption. Shows the increasing bypass ratio to be a rational step for reducing the fuel consumption. Also considers the basic features of engines with a high bypass ratio. Among the other working process parameters, fan pressure ratio and bypass ratio are the most relevant for consideration as they are the most structural variables at a given level of technical excellence. The paper presents the dependence of the nacelle drag coefficient on the engine bypass ratio. For computation were adopted the projected parameters of prospective turbofans to be used in the power plant of the 180-seat medium-haul aircraft. Computation of the engine cycle was performed in Mathcad using these data, with fan pressure ratio and bypass ratio being varied. The combustion chamber gas temperature, the overall pressure ratio and engine thrust remained constant. Pressure loss coefficients, the efficiency of the engine components and the amount of air taken for cooling also remained constant. The optimal parameters corresponding to the minimum effective specific fuel consumption were found as the result of computation. The paper gives recommendations for adjusting optimal parameters, depending on the considered external factors, such as weight of engine and required fuel reserve. The obtained data can be used to estimate parameters of future turbofan engines with high bypass ratio.

  11. Matrix population models from 20 studies of perennial plant populations

    Science.gov (United States)

    Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.

    2012-01-01

    Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the 'Testing Matrix Models' working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.

  12. Optimum combinations of visible and near-infrared reflectances for estimating the fraction of photosynthetically available radiation absorbed by plants

    Science.gov (United States)

    Podaire, Alain; Deschamps, Pierre-Yves; Frouin, R.; Asrar, Ghassem

    1991-01-01

    A useful parameter to estimate terrestrial primary productivity, that can be sensed from space, is the daily averaged fraction of Photosynthetically Available Radiation (PAR) absorbed by plants. To evaluate this parameter, investigators have relied on the fact that the relative amount of radiation reflected by a vegetated surface in the visible and near infrared depends on the fraction of the surface covered by the vegetation and therefore, correlates with absorbed PAR. They have used vegetation indices, namely normalized difference and simple ratio, to derive absorbed PAR. The problem with normalized difference and simple ratio is first, they are non linear functions of radiance or reflectance and therefore, cannot be readily applied to heterogeneous targets, second, they are used in generally nonlinear relationships, which make time integrals of the indices not proportional to primary productivity, and third, the relationships depend strongly on the type of canopy and background. To remove these limitations, linear combinations of visible and near infrared reflectances at optimum (one or two) viewing zenith angles are proposed.

  13. OPTIMUM PROSESSENTRERING

    Directory of Open Access Journals (Sweden)

    K. Adendorff

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The paper derives an expression for optimum process centreing for a given design specification and spoilage and/or rework costs.

    AFRIKAANSE OPSOMMING: Die problem Van prosessentrering vir n gegewe ontwerpspesifikasie en herwerk- en/of skrootkoste word behandel.

  14. Host plant adaptation in Drosophila mettleri populations.

    Directory of Open Access Journals (Sweden)

    Sergio Castrezana

    Full Text Available The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total. We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp. in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts.

  15. Population trends around nuclear power plants

    International Nuclear Information System (INIS)

    Greenberg, M.; Krueckeberg, D.A.; Kaltman, M.

    1984-01-01

    Site selection criteria used by the Nuclear Regulatory Commission emphasize the selection of low population areas in which little growth is anticipated. This research examines population growth after site selection for the period 1960 to 1980 for forty-three operating sites. Substantial increments of population increase were found, only partially explained by national, regional, and host county growth trends impacting local host areas. These local components of change became especially important in the decade of the 1970s, when most of the plants were in full operation. The decade of the 1970s also saw a marked shift from the geographic pattern of growth of the 60s, when few plants were in operation. These larger and different growth components of the 1970s, also unexplained by preliminary analysis of correlation with coastal locations and degree of urbanization, are classified into categories with high potential and interest for further research

  16. Application of numerical simulation on optimum design of two-dimensional sedimentation tanks in the wastewater treatment plant.

    Science.gov (United States)

    Zeng, Guang-Ming; Zhang, Shuo-Fu; Qin, Xiao-Sheng; Huang, Guo-He; Li, Jian-Bing

    2003-05-01

    The paper establishes the relationship between the settling efficiency and the sizes of the sedimentation tank through the process of numerical simulation, which is taken as one of the constraints to set up a simple optimum designing model of sedimentation tank. The feasibility and advantages of this model based on numerical calculation are verified through the application of practical case.

  17. An optimum city size? The scaling relationship for urban population and fine particulate (PM_2_._5) concentration

    International Nuclear Information System (INIS)

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

    2016-01-01

    We utilize the distribution of PM_2_._5 concentration and population in large cities at the global scale to illustrate the relationship between urbanization and urban air quality. We found: 1) The relationship varies greatly among continents and countries. Large cities in North America, Europe, and Latin America have better air quality than those in other continents, while those in China and India have the worst air quality. 2) The relationships between urban population size and PM_2_._5 concentration in large cities of different continents or countries were different. PM_2_._5 concentration in large cities in North America, Europe, and Latin America showed little fluctuation or a small increasing trend, but those in Africa and India represent a “U” type relationship and in China represent an inverse “U” type relationship. 3) The potential contribution of population to PM_2_._5 concentration was higher in the large cities in China and India, but lower in other large cities. - Highlights: • Urban population and PM_2_._5 concentration varies greatly among regions. • Urban population size increase does not always enhances PM_2_._5 concentration. • Population's potential contribution to PM_2_._5 concentration higher in China. - We utilize the distribution of PM_2_._5 concentration and population in large cities at the global scale to illustrate the relationship between urbanization and urban air quality.

  18. Simulation of the power plant unit for the purpose of accident analysis and optimum countermeasures. Pt. 2

    International Nuclear Information System (INIS)

    Dolezal, R.

    1982-01-01

    Description of a computer program to enable a process computer connected 'on-line' with the power block 1) to identify the nature and probable cause of an occuring failure, and 2) to influence the plant by means of a pre-planned failure removal strategy in such manner that not only a considerable secondary failure is avoided but that the plant, as far as possible, is kept operating. (orig.) [de

  19. Ecological and population genetics of locally rare plants: A review

    Science.gov (United States)

    Simon A. Lei

    2001-01-01

    Plant species with limited dispersal ability, narrow geographical and physiological tolerance ranges, as well as with specific habitat and ecological requirements are likely to be rare. Small and isolated populations and species contain low levels of within-population genetic variation in many plant species. The gene pool of plants is a product of phenotype-environment...

  20. Biomethanol production from gasification of non-woody plant in South Africa: Optimum scale and economic performance

    Energy Technology Data Exchange (ETDEWEB)

    Amigun, Bamikole, E-mail: bamigun@csir.co.z [Sustainable Energy Futures, Natural Resources and the Environment, Council for Scientific and Industrial Research (CSIR), Pretoria (South Africa); Process Engineering Department, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602 (South Africa); Gorgens, Johann; Knoetze, Hansie [Process Engineering Department, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602 (South Africa)

    2010-01-15

    Methanol production from biomass is a promising carbon neutral fuel, well suited for use in fuel cell vehicles (FCVs), as transportation fuel and as chemical building block. The concept used in this study incorporates an innovative Absorption Enhanced Reforming (AER) gasification process, which enables an efficient conversion of biomass into a hydrogen-rich gas (syngas) and then, uses the Mitsubishi methanol converter (superconverter) for methanol synthesis. Technical and economic prospects for production of methanol have been evaluated. The methanol plants described have a biomass input between 10 and 2000 MW{sub th}. The economy of the methanol production plants is very dependent on the production capacity and large-scale facilities are required to benefit from economies of scale. However, large-scale plants are likely to have higher transportation costs per unit biomass transported as a result of longer transportation distances. Analyses show that lower unit investment costs accompanying increased production scale outweighs the cost for transporting larger quantities of biomass. The unit cost of methanol production mostly depends on the capital investments. The total unit cost of methanol is found to decrease from about 10.66 R/l for a 10 MW{sub th} to about 6.44 R/l for a 60 MW{sub th} and 3.95 R/l for a 400 MW{sub th} methanol plant. The unit costs stabilise (a near flat profile was observed) for plant sizes between 400 and 2000 MW{sub th}, but the unit cost do however continue to decrease to about 2.89 R/l for a 2000 MW{sub th} plant. Long term cost reduction mainly resides in technological learning and large-scale production. Therefore, technology development towards large-scale technology that takes into account sustainable biomass production could be a better choice due to economic reasons.

  1. Biomethanol production from gasification of non-woody plant in South Africa. Optimum scale and economic performance

    Energy Technology Data Exchange (ETDEWEB)

    Amigun, Bamikole [Sustainable Energy Futures, Natural Resources and the Environment, Council for Scientific and Industrial Research (CSIR), Pretoria (South Africa); Process Engineering Department, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602 (South Africa); Gorgens, Johann; Knoetze, Hansie [Process Engineering Department, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602 (South Africa)

    2010-01-15

    Methanol production from biomass is a promising carbon neutral fuel, well suited for use in fuel cell vehicles (FCVs), as transportation fuel and as chemical building block. The concept used in this study incorporates an innovative Absorption Enhanced Reforming (AER) gasification process, which enables an efficient conversion of biomass into a hydrogen-rich gas (syngas) and then, uses the Mitsubishi methanol converter (superconverter) for methanol synthesis. Technical and economic prospects for production of methanol have been evaluated. The methanol plants described have a biomass input between 10 and 2000 MW{sub th}. The economy of the methanol production plants is very dependent on the production capacity and large-scale facilities are required to benefit from economies of scale. However, large-scale plants are likely to have higher transportation costs per unit biomass transported as a result of longer transportation distances. Analyses show that lower unit investment costs accompanying increased production scale outweighs the cost for transporting larger quantities of biomass. The unit cost of methanol production mostly depends on the capital investments. The total unit cost of methanol is found to decrease from about 10.66 R/l for a 10 MW{sub th} to about 6.44 R/l for a 60 MW{sub th} and 3.95 R/l for a 400 MW{sub th} methanol plant. The unit costs stabilise (a near flat profile was observed) for plant sizes between 400 and 2000 MW{sub th}, but the unit cost do however continue to decrease to about 2.89 R/l for a 2000 MW{sub th} plant. Long term cost reduction mainly resides in technological learning and large-scale production. Therefore, technology development towards large-scale technology that takes into account sustainable biomass production could be a better choice due to economic reasons. (author)

  2. Biomethanol production from gasification of non-woody plant in South Africa: Optimum scale and economic performance

    International Nuclear Information System (INIS)

    Amigun, Bamikole; Gorgens, Johann; Knoetze, Hansie

    2010-01-01

    Methanol production from biomass is a promising carbon neutral fuel, well suited for use in fuel cell vehicles (FCVs), as transportation fuel and as chemical building block. The concept used in this study incorporates an innovative Absorption Enhanced Reforming (AER) gasification process, which enables an efficient conversion of biomass into a hydrogen-rich gas (syngas) and then, uses the Mitsubishi methanol converter (superconverter) for methanol synthesis. Technical and economic prospects for production of methanol have been evaluated. The methanol plants described have a biomass input between 10 and 2000 MW th . The economy of the methanol production plants is very dependent on the production capacity and large-scale facilities are required to benefit from economies of scale. However, large-scale plants are likely to have higher transportation costs per unit biomass transported as a result of longer transportation distances. Analyses show that lower unit investment costs accompanying increased production scale outweighs the cost for transporting larger quantities of biomass. The unit cost of methanol production mostly depends on the capital investments. The total unit cost of methanol is found to decrease from about 10.66 R/l for a 10 MW th to about 6.44 R/l for a 60 MW th and 3.95 R/l for a 400 MW th methanol plant. The unit costs stabilise (a near flat profile was observed) for plant sizes between 400 and 2000 MW th , but the unit cost do however continue to decrease to about 2.89 R/l for a 2000 MW th plant. Long term cost reduction mainly resides in technological learning and large-scale production. Therefore, technology development towards large-scale technology that takes into account sustainable biomass production could be a better choice due to economic reasons.

  3. Nitrogen rate and plant population effects on yield and yield ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... density and nitrogen rate increased plant height, lowest pod height, harvest index and seed yield. ... since some combine harvester heads are unable to pick ..... as effected by population density and plant distribution.

  4. Reliability-based service life assessment of concrete structures in nuclear power plants: optimum inspection and repair

    International Nuclear Information System (INIS)

    Ellingwood, B.R.; Mori, Y.

    1995-01-01

    Research is being conducted to address aging management of safety-related reinforced concrete structures in nuclear power plants (NPPs). Documentation is being prepared to identify potential structural safety issues and to recommend criteria for use in evaluating reinforced concrete structures for continued service. Time-dependent reliability analysis provides the framework and quantitative tools for the condition assessment. The role of in-service inspection and repair in ensuring continued reliability in-service is examined. (author). 19 refs., 4 figs

  5. Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress.

    Science.gov (United States)

    Porcel, Rosa; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique; Aroca, Ricardo; Garcia, Rosalva; Ruiz-Lozano, Juan Manuel

    2015-08-01

    Rice is the most important food crop in the world and is a primary source of food for more than half of the world population. However, salinity is considered the most common abiotic stress reducing its productivity. Soil salinity inhibits photosynthetic processes, which can induce an over-reduction of the reaction centres in photosystem II (PSII), damaging the photosynthetic machinery. The arbuscular mycorrhizal (AM) symbiosis may improve host plant tolerance to salinity, but it is not clear how the AM symbiosis affects the plant photosynthetic capacity, particularly the efficiency of PSII. This study aimed at determining the influence of the AM symbiosis on the performance of PSII in rice plants subjected to salinity. Photosynthetic activity, plant gas-exchange parameters, accumulation of photosynthetic pigments and rubisco activity and gene expression were also measured in order to analyse comprehensively the response of the photosynthetic processes to AM symbiosis and salinity. Results showed that the AM symbiosis enhanced the actual quantum yield of PSII photochemistry and reduced the quantum yield of non-photochemical quenching in rice plants subjected to salinity. AM rice plants maintained higher net photosynthetic rate, stomatal conductance and transpiration rate than nonAM plants. Thus, we propose that AM rice plants had a higher photochemical efficiency for CO2 fixation and solar energy utilization and this increases plant salt tolerance by preventing the injury to the photosystems reaction centres and by allowing a better utilization of light energy in photochemical processes. All these processes translated into higher photosynthetic and rubisco activities in AM rice plants and improved plant biomass production under salinity. Copyright © 2015 Elsevier GmbH. All rights reserved.

  6. Projecting the success of plant restoration with population viability analysis

    Science.gov (United States)

    Bell, T.J.; Bowles, M.L.; McEachern, A.K.; Brigham, C.A.; Schwartz, M.W.

    2003-01-01

    Conserving viable populations of plant species requires that they have high probabilities of long-term persistence within natural habitats, such as a chance of extinction in 100 years of less than 5% (Menges 1991, 1998; Brown 1994; Pavlik 1994; Chap. 1, this Vol.). For endangered and threatened species that have been severely reduces in range and whose habitats have been fragmented, important species conservation strategies may include augmenting existing populations or restoring new viable populations (Bowles and Whelan 1994; Chap. 2, this Vol.). Restoration objectives may include increasing population numbers to reduce extinction probability, deterministic manipulations to develop a staged cohort structure, or more complex restoration of a desired genetic structure to allow outcrossing or increase effective population size (DeMauro 1993, 1994; Bowles et al. 1993, 1998; Pavlik 1994; Knapp and Dyer 1998; Chap. 2, this Vol.). These efforts may require translocation of propagules from existing (in situ) populations, or from ex situ botanic gardens or seed storage facilities (Falk et al. 1996; Guerrant and Pavlik 1998; Chap. 2, this Vol.). Population viability analysis (PVA) can provide a critical foundation for plant restoration, as it models demographic projections used to evaluate the probability of population persistence and links plant life history with restoration strategies. It is unknown how well artificially created populations will meet demographic modeling requirements (e.g., due to artificial cohort transitions) and few, if any, PVAs have been applied to restorations. To guide application of PVA to restored populations and to illustrate potential difficulties, we examine effects of planting different life stages, model initial population sizes needed to achieve population viability, and compare demographic characteristics between natural and restored populations. We develop and compare plant population restoration viability analysis (PRVA) case studies of

  7. Choosing the optimum burnup

    International Nuclear Information System (INIS)

    Geller, L.; Goldstein, L.; Franks, W.A.

    1986-01-01

    This paper reviews some of the considerations utilities must evaluate when going to higher discharge burnups. The advantages and disadvantages of higher discharge burnups are described, as well as a consistent approach for evaluating optimum discharge burnup and its comparison to current practice. When an analysis is performed over the life of the plant, the design of the terminal cycles has significant impact on the lifetime savings from higher burnups. Designs for high burnup cycles have a greater average inventory value in the core. As one goes to higher burnup, there is a greater likelihood of discarding a larger value in unused fuel unless the terminal cycles are designed carefully. This effect can be large enough in some cases to wipe out the lifetime cost savings relative to operating with a higher discharge burnup cycle

  8. Population Exposure Estimates in Proximity to Nuclear Power Plants, Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — The Population Exposure Estimates in Proximity to Nuclear Power Plants, Locations data set combines information from a global data set developed by Declan Butler of...

  9. The effect of plant population and nitrogen fertilizer on

    Directory of Open Access Journals (Sweden)

    mohamad reza asgaripor

    2009-06-01

    Full Text Available Interest has increased towards hemp (Cannabis sativa L. fibre production due to renewed demand for natural fibre in the world. A Study was conducted in 2005 at Shirvan in Northern Khorasan province, Iran, to determine the effects of three plant populations (30, 90 and 150 plant per m2 and three rates of nitrogen application (50, 150 and 250 kg N per ha on final stand, stalk height, basal stalk diameter, total stalk yield as well as fibre content from stalk and fibre yield in male and female plants. A split plot experimental with three replications was used. The result indicated that due to enhanced competition for light at higher population on density and N2 level plant mortality was higher than other treatment Morphological characteristics were highly correlated with plant sexual, plant population and nitrogen fertilizer. Highest stem, leaf and inflorescence yield were obtained at 250 plant m-2 when 150 kg N ha-1 was used. Lowest plant density did not show self-thinning but reduced above ground dry matter. Shoot dry matter increased with increasing plant density and nitrogen supply. Apparently, fibre content was greater at medium density and lowest nitrogen fertilizer, however, fibre yield was greatest at highest plant population and nitrogen fertilizer. In terms of fibre yield, approximate 31.7% of the fibre was located in the bottom parts, 22.4% in the middle and only 9.9% in the top part of the stem. The results suggest that hemp can yield large quantities of useful fibre at Shirvan when planted in proper plant densities and suitable nitrogen fertilizer.

  10. Human population, grasshopper and plant species richness in European countries

    Science.gov (United States)

    Steck, Claude E.; Pautasso, Marco

    2008-11-01

    Surprisingly, several studies over large scales have reported a positive spatial correlation of people and biodiversity. This pattern has important implications for conservation and has been documented for well studied taxa such as plants, amphibians, reptiles, birds and mammals. However, it is unknown whether the pattern applies also to invertebrates other than butterflies and more work is needed to establish whether the species-people relationship is explained by both variables correlating with other environmental factors. We studied whether grasshopper species richness (Orthoptera, suborder Caelifera) is related to human population size in European countries. As expected, the number of Caelifera species increases significantly with increasing human population size. But this is not the case when controlling for country area, latitude and number of plant species. Variations in Caelifera species richness are primarily associated with variations in plant species richness. Caelifera species richness also increases with decreasing mean annual precipitation, Gross Domestic Product per capita (used as an indicator for economic development) and net fertility rate of the human population. Our analysis confirms the hypothesis that the broad-scale human population-biodiversity correlations can be explained by concurrent variations in factors other than human population size such as plant species richness, environmental productivity, or habitat heterogeneity. Nonetheless, more populated countries in Europe still have more Caelifera species than less populated countries and this poses a particular challenge for conservation.

  11. Application of the method of optimum increase of Carboniferous gass exploitation for the determination of its extractable amount from the space of attenuated plant of the Paskov Mine

    Directory of Open Access Journals (Sweden)

    Dragon Vladimír

    2003-09-01

    Full Text Available A way of optimum extraction increase of Carboniferous gas which can be applied in any mine of the Ostrava-Karviná Mining District (OKMD during the current period of the restructuralisation and mining attenuation.

  12. Effects of an invasive plant on population dynamics in toads.

    Science.gov (United States)

    Greenberg, Daniel A; Green, David M

    2013-10-01

    When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

  13. Nondissipative optimum charge regulator

    Science.gov (United States)

    Rosen, R.; Vitebsky, J. N.

    1970-01-01

    Optimum charge regulator provides constant level charge/discharge control of storage batteries. Basic power transfer and control is performed by solar panel coupled to battery through power switching circuit. Optimum controller senses battery current and modifies duty cycle of switching circuit to maximize current available to battery.

  14. Ambit determination method in estimating rice plant population density

    Directory of Open Access Journals (Sweden)

    Abu Bakar, B.,

    2017-11-01

    Full Text Available Rice plant population density is a key indicator in determining the crop setting and fertilizer application rate. It is therefore essential that the population density is monitored to ensure that a correct crop management decision is taken. The conventional method of determining plant population is by manually counting the total number of rice plant tillers in a 25 cm x 25 cm square frame. Sampling is done by randomly choosing several different locations within a plot to perform tiller counting. This sampling method is time consuming, labour intensive and costly. An alternative fast estimating method was developed to overcome this issue. The method relies on measuring the outer circumference or ambit of the contained rice plants in a 25 cm x 25 cm square frame to determine the number of tillers within that square frame. Data samples of rice variety MR219 were collected from rice plots in the Muda granary area, Sungai Limau Dalam, Kedah. The data were taken at 50 days and 70 days after seeding (DAS. A total of 100 data samples were collected for each sampling day. A good correlation was obtained for the variety of 50 DAS and 70 DAS. The model was then verified by taking 100 samples with the latching strap for 50 DAS and 70 DAS. As a result, this technique can be used as a fast, economical and practical alternative to manual tiller counting. The technique can potentially be used in the development of an electronic sensing system to estimate paddy plant population density.

  15. Intervention analysis of power plant impact on fish populations

    International Nuclear Information System (INIS)

    Madenjian, C.P.

    1984-01-01

    Intervention analysis was applied to 10 yr (years 1973-1982) of field fish abundance data at the D. C. Cook Nuclear Power Plant, southeastern Lake Michigan. Three log-transformed catch series, comprising monthly observations, were examined for each combination of two species (alewife, Alosa pseudoharenga, or yellow perch, Perca flavescens) and gear (trawl or gill net): catch at the plant discharged transect, catch at the reference transect, and the ratio of plant catch to reference catch. Time series separated by age groups were examined. Based on intervention analysis, no change in the abundance of fish populations could be attributed to plant operation. Additionally, a modification of the intervention analysis technique was applied to investigate trends in abundance at both the plant discharge and reference transects. Significant declines were detected for abundance of alewife adults at both of the transects. Results of the trend analysis support the contention that the alewives have undergone a lakewide decrease in abundance during the 1970s

  16. Plant Mating Systems Often Vary Widely Among Populations

    Directory of Open Access Journals (Sweden)

    Michael R. Whitehead

    2018-04-01

    Full Text Available Most flowering plants are hermaphroditic, yet the proportion of seeds fertilized by self and outcross pollen varies widely among species, ranging from predominant self-fertilization to exclusive outcrossing. A population's rate of outcrossing has important evolutionary outcomes as it influences genetic structure, effective population size, and offspring fitness. Because most mating system studies have quantified outcrossing rates for just one or two populations, past reviews of mating system diversity have not been able to characterize the extent of variation among populations. Here we present a new database of more than 30 years of mating system studies that report outcrossing rates for three or more populations per species. This survey, which includes 741 populations from 105 species, illustrates substantial and prevalent among-population variation in the mating system. Intermediate outcrossing rates (mixed mating are common; 63% of species had at least one mixed mating population. The variance among populations and within species was not significantly correlated with pollination mode or phylogeny. Our review underscores the need for studies exploring variation in the relative influence of ecological and genetic factors on the mating system, and how this varies among populations. We conclude that estimates of outcrossing rates from single populations are often highly unreliable indicators of the mating system of an entire species.

  17. Radiation burden of population in nuclear power plant siting

    International Nuclear Information System (INIS)

    Navratil, J.

    The significance is discussed of the determination of the radiobiological consequences of normal operation and design basis accidents in nuclear power plant siting. The basic diagram and brief description is given of the programme for calculating the radiation load of the population in the surroundings of the nuclear power plant. The programme consists of two subprogrammes, i.e., the dispersion of radioactive gases (for normal operation and for accidents), the main programme for the determination of biological consequences and one auxiliary programme (the distribution of the population in the surroundings of the power plant). The four most important types of exposure to ionizing radiation are considered, namely inhalation, external irradiation from a cloud, ingestion (water, milk, vegetables), external irradiation from the deposit. (B.S.)

  18. Effects of host-plant population size and plant sex on a specialist leaf-miner

    DEFF Research Database (Denmark)

    Bañuelos, María-José; Kollmann, Johannes Christian

    2011-01-01

    of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different...... punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively...... stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size...

  19. Effects of host-plant population size and plant sex on a specialist leaf-miner

    Science.gov (United States)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  20. Individualism in plant populations: using stochastic differential equations to model individual neighbourhood-dependent plant growth.

    Science.gov (United States)

    Lv, Qiming; Schneider, Manuel K; Pitchford, Jonathan W

    2008-08-01

    We study individual plant growth and size hierarchy formation in an experimental population of Arabidopsis thaliana, within an integrated analysis that explicitly accounts for size-dependent growth, size- and space-dependent competition, and environmental stochasticity. It is shown that a Gompertz-type stochastic differential equation (SDE) model, involving asymmetric competition kernels and a stochastic term which decreases with the logarithm of plant weight, efficiently describes individual plant growth, competition, and variability in the studied population. The model is evaluated within a Bayesian framework and compared to its deterministic counterpart, and to several simplified stochastic models, using distributional validation. We show that stochasticity is an important determinant of size hierarchy and that SDE models outperform the deterministic model if and only if structural components of competition (asymmetry; size- and space-dependence) are accounted for. Implications of these results are discussed in the context of plant ecology and in more general modelling situations.

  1. Project subsidized by the Sunshine Project in fiscal 1982. Report on achievements in the project commissioned from NEDO - development of a hot water utilizing power generation plant and development of a binary cycle power generation plant (Researches on corrosion preventive measures and the cycle optimum for the plant); 1982 nendo nessui riyo hatsuden plant no kaihatsu seika hokokusho. Binary cycle hatsuden plant no kaihatsu (fushoku taisaku no kenkyu oyobi plant saiteki cycle no kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1983-03-01

    As the element research on a 10-MW class geothermal binary cycle power plant to be built in the coming term, researches were made on corrosion preventive measures and the cycle optimum for the plant. This paper reports the achievements in fiscal 1982. In the research on corrosion preventive measures, different kinds of materials were buried in three locations having different soil natures to study corrosion due to soil. The corrosion rate of heat conducting pipes using the heat media R114 was estimated as very small as 1/40 of the corrosion rate in geothermal waters. In the research on the cycle optimum for the plant, experimental research was performed on thermo-dynamic properties and thermal stability of the mixed media using R114 as the main component. As a result, the R114/R112 system was found to have higher pressure than R114, but the media circulation amount is less, and the output at the power transmission terminal increased by 5 to 10%. The system showed the most excellent heat cycle characteristics. In the research of building a power plant installed with two different power generation systems, a computer program was prepared that calculates heat balances all at once for the case of installing a geothermal binary cycle power plant in a geothermal steam power plant. (NEDO)

  2. Effects in Plant Populations Resulting from Chronic Radiation Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Geras' kin, Stanislav A.; Volkova, Polina Yu.; Vasiliyev, Denis V.; Dikareva, Nina S.; Oudalova, Alla A. [Russian Institute of Agricultural Radiology and Agroecology, 249032, Obninsk (Russian Federation)

    2014-07-01

    Human industrial activities have left behind a legacy of ecosystems strongly impacted by a wide range of contaminants, including radionuclides. Phyto-toxic effects of acute impact are well known, but the consequences of long-term chronic exposure to low pollutant concentrations is neither well understood nor adequately included in risk assessments. To understand effects of real-world contaminant exposure properly we must pay attention to what is actually going on in the field. However, for many wildlife groups and endpoints, there are no, or very few, studies that link accumulation, chronic exposure and biological effects in natural settings. To fill the gaps, results of field studies carried out on different plant species (winter rye and wheat, spring barley, oats, Scots pine, wild vetch, crested hair-grass) in various radioecological situations (nuclear weapon testing, the Chernobyl accident, uranium and radium processing) to investigate effects of long-term chronic exposure to radionuclides are discussed. Because each impacted site developed in its own way due to a unique history of events, the experience from one case study is rarely directly applicable to another situation. In spite of high heterogeneity in response, we have detected several general patterns. Plant populations growing in areas with relatively low levels of pollution are characterized by the increased level of both cytogenetic alterations and genetic diversity. Accumulation of cellular alterations may afterward influence biological parameters important for populations such as health and reproduction. Presented data provide evidence that in plant populations inhabiting heavily contaminated territories cytogenetic damage were accompanied by decrease in reproductive ability. In less contaminated sites, because of the scarcity of data available, it is impossible to establish exactly the relationship between cytogenetic effects and reproductive ability. Radioactive contamination of the plants

  3. Do we need demographic data to forecast plant population dynamics?

    Science.gov (United States)

    Tredennick, Andrew T.; Hooten, Mevin B.; Adler, Peter B.

    2017-01-01

    Rapid environmental change has generated growing interest in forecasts of future population trajectories. Traditional population models built with detailed demographic observations from one study site can address the impacts of environmental change at particular locations, but are difficult to scale up to the landscape and regional scales relevant to management decisions. An alternative is to build models using population-level data that are much easier to collect over broad spatial scales than individual-level data. However, it is unknown whether models built using population-level data adequately capture the effects of density-dependence and environmental forcing that are necessary to generate skillful forecasts.Here, we test the consequences of aggregating individual responses when forecasting the population states (percent cover) and trajectories of four perennial grass species in a semi-arid grassland in Montana, USA. We parameterized two population models for each species, one based on individual-level data (survival, growth and recruitment) and one on population-level data (percent cover), and compared their forecasting accuracy and forecast horizons with and without the inclusion of climate covariates. For both models, we used Bayesian ridge regression to weight the influence of climate covariates for optimal prediction.In the absence of climate effects, we found no significant difference between the forecast accuracy of models based on individual-level data and models based on population-level data. Climate effects were weak, but increased forecast accuracy for two species. Increases in accuracy with climate covariates were similar between model types.In our case study, percent cover models generated forecasts as accurate as those from a demographic model. For the goal of forecasting, models based on aggregated individual-level data may offer a practical alternative to data-intensive demographic models. Long time series of percent cover data already exist

  4. On Optimum Stratification

    OpenAIRE

    M. G. M. Khan; V. D. Prasad; D. K. Rao

    2014-01-01

    In this manuscript, we discuss the problem of determining the optimum stratification of a study (or main) variable based on the auxiliary variable that follows a uniform distribution. If the stratification of survey variable is made using the auxiliary variable it may lead to substantial gains in precision of the estimates. This problem is formulated as a Nonlinear Programming Problem (NLPP), which turn out to multistage decision problem and is solved using dynamic programming technique.

  5. Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

    Science.gov (United States)

    Olapade, Ola A; Pung, Kayleigh

    2012-06-01

    Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus.

  6. Population and community ecology of the rare plant amsinckia grandiflora

    Energy Technology Data Exchange (ETDEWEB)

    Carlsen, T.M.

    1996-11-01

    Research was conducted between the fall of 1992 and the spring on the population and community ecology of the rare annual plant, Amsinckia glandiflora (Gray) Kleeb. ex Greene (Boraginaceae). The research goal was to investigate the causes of the species rarity, data useful to restorative efforts. The work focused on the examination of competitive suppression by exotic annual grasses; comparisons with common, weedy congener; and the role of litter cover and seed germination and seedling establishment. Annual exotic grasses reduced A. grandiflora reproductive output to a greater extent than did the native perennial bunch grass.

  7. Optimum coolant chemistry in BWRs

    International Nuclear Information System (INIS)

    Lin, C.C.; Cowan, R.L.; Kiss, E.

    2004-01-01

    LWR water chemistry parameters are directly or indirectly related to the plant's operational performance and for a significant amount of Operation and Maintenance (O and M) costs. Obvious impacts are the operational costs associated with water treatment, monitoring and associated radwaste generation. Less obvious is the important role water chemistry plays in the magnitude of drywell shutdown dose rates, fuel corrosion performance and, (probably most importantly) materials degradation such as from stress corrosion cracking of piping and Reactor Pressure Vessel (RPV) internal components. To improve the operational excellence of the BWR and to minimize the impact of water chemistry on O and M costs. General Electric has developed the concept of Optimum Water Chemistry (OWC). The 'best practices' and latest technology findings from the U.S., Asia and Europe are integrated into the suggested OWC Specification. This concept, together with cost effective ways to meet the requirement, are discussed. (author)

  8. The optimum spanning catenary cable

    Science.gov (United States)

    Wang, C. Y.

    2015-03-01

    A heavy cable spans two points in space. There exists an optimum cable length such that the maximum tension is minimized. If the two end points are at the same level, the optimum length is 1.258 times the distance between the ends. The optimum lengths for end points of different heights are also found.

  9. Effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers

    Science.gov (United States)

    Batten, J. H.; Stutte, G. W.; Wheeler, R. M.

    1995-01-01

    The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence.

  10. Design of ANFIS Structures and GMDH Type-Neural Network for Prediction of Optimum Coagulant Dosage in Water Treatment Process Case Study: Great Water Treatment Plant in Guilan Province

    Directory of Open Access Journals (Sweden)

    Allahyar Daghbandan

    2015-11-01

    Full Text Available Given the increasing importance of surface water bodies as supply sources of drinking water and regarding the requirement for using different chemicals at various stages of water treatment processes, it is essential to investigate coagulant consumption in water treatment plants. Determination of the required dosage of coagulants used in the coagulation and flocculation unit is one of the most important decisions in water treatment operations. For this purpose, the jar test is generally used to determine the type and concentration of suitable coagulants in a water treatment plant. However, the test is rather time-consuming and unreliable due to the inaccurate results it yields. Instead, intelligent methods can be employed to overcome this shortcoming of the jar test. In this study, experimental data were collected over the period from 2011 to 2012 and further refined for study. Two non-linear models based on adaptive neuro-fuzzy inference system (ANFIS and GMDH-type neural networks were then developed and experimental results were used to determine the optimum poly-aluminium chloride dosage for use at Guilan water treatment plant. The effects of input parameters including temperature, pH, turbidity, suspended solids, electrical conductivity, and color were investigated on coagulant dosage. The ANFIS model was found to outperform the GMDH model in predicting the required poly-aluminium chloride dosage.

  11. Optimum Dispatch of Hybrid Solar Thermal (HSTP Electric Power Plant Using Non-Smooth Cost Function and Emission Function for IEEE-30 Bus System

    Directory of Open Access Journals (Sweden)

    Saroj Kumar Dash

    2016-07-01

    Full Text Available The basic objective of economic load dispatch (ELD is to optimize the total fuel cost of hybrid solar thermal electric power plant (HSTP. In ELD problems the cost function for each generator has been approximated by a single quadratic cost equation. As cost of coal increases, it becomes even more important have a good model for the production cost of each generator for the solar thermal hybrid system. A more accurate formulation is obtained for the ELD problem by expressing the generation cost function as a piece wise quadratic cost function. However, the solution methods for ELD problem with piece wise quadratic cost function requires much complicated algorithms such as the hierarchical structure approach along with evolutionary computations (ECs. A test system comprising of 10 units with 29 different fuel [7] cost equations is considered in this paper. The applied genetic algorithm method will provide optimal solution for the given load demand.

  12. Optimum design of a nuclear heat supply

    International Nuclear Information System (INIS)

    Borel, J.P.

    1984-01-01

    This paper presents an economic analysis for the optimum design of a nuclear heat supply to a given district-heating network. First, a general description of the system is given, which includes a nuclear power plant, a heating power plant and a district-heating network. The heating power plant is fed with steam from the nuclear power plant. It is assumed that the heating network is already in operation and that the nuclear power plant was previously designed to supply electricity. Second, a technical definition of the heat production and transportation installations is given. The optimal power of these installations is examined. The main result is a relationship between the network capacity and the level of the nuclear heat supply as a substitute for oil under the best economic conditions. The analysis also presents information for choosing the best operating mode. Finally, the heating power plant is studied in more detail from the energy, technical and economic aspects. (author)

  13. Model of yield response of corn to plant population and absorption of solar energy.

    Directory of Open Access Journals (Sweden)

    Allen R Overman

    Full Text Available Biomass yield of agronomic crops is influenced by a number of factors, including crop species, soil type, applied nutrients, water availability, and plant population. This article is focused on dependence of biomass yield (Mg ha(-1 and g plant(-1 on plant population (plants m(-2. Analysis includes data from the literature for three independent studies with the warm-season annual corn (Zea mays L. grown in the United States. Data are analyzed with a simple exponential mathematical model which contains two parameters, viz. Y(m (Mg ha(-1 for maximum yield at high plant population and c (m(2 plant(-1 for the population response coefficient. This analysis leads to a new parameter called characteristic plant population, x(c = 1/c (plants m(-2. The model is shown to describe the data rather well for the three field studies. In one study measurements were made of solar radiation at different positions in the plant canopy. The coefficient of absorption of solar energy was assumed to be the same as c and provided a physical basis for the exponential model. The three studies showed no definitive peak in yield with plant population, but generally exhibited asymptotic approach to maximum yield with increased plant population. Values of x(c were very similar for the three field studies with the same crop species.

  14. Nitrogen rate and plant population effects on yield and yield ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Gan et al., 2003). Nitrogen increases yield by influencing a variety of agronomic and quality parameters. In general, there was an increase in plant height and dry matter accumulation per plant in soybean (Manral and Saxena, ...

  15. Modeling the growth of individuals in plant populations: local density variation in a strand population of Xanthium strumarium (Asteraceae).

    Science.gov (United States)

    Weiner, J; Kinsman, S; Williams, S

    1998-11-01

    We studied the growth of individual Xanthium strumarium plants growing at four naturally occurring local densities on a beach in Maine: (1) isolated plants, (2) pairs of plants ≤1 cm apart, (3) four plants within 4 cm of each other, and (4) discrete dense clumps of 10-39 plants. A combination of nondestructive measurements every 2 wk and parallel calibration harvests provided very good estimates of the growth in aboveground biomass of over 400 individual plants over 8 wk and afforded the opportunity to fit explicit growth models to 293 of them. There was large individual variation in growth and resultant size within the population and within all densities. Local crowding played a role in determining plant size within the population: there were significant differences in final size between all densities except pairs and quadruples, which were almost identical. Overall, plants growing at higher densities were more variable in growth and final size than plants growing at lower densities, but this was due to increased variation among groups (greater variation in local density and/or greater environmental heterogeneity), not to increased variation within groups. Thus, there was no evidence of size asymmetric competition in this population. The growth of most plants was close to exponential over the study period, but half the plants were slightly better fit by a sigmoidal (logistic) model. The proportion of plants better fit by the logistic model increased with density and with initial plant size. The use of explicit growth models over several growth intervals to describe stand development can provide more biological content and more statistical power than "growth-size" methods that analyze growth intervals separately.

  16. Highly Diverse Endophytic and Soil Fusarium oxysporum Populations Associated with Field-Grown Tomato Plants

    Science.gov (United States)

    Demers, Jill E.; Gugino, Beth K.

    2014-01-01

    The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants. Included in this total were 112 isolates from the stems of all 32 plants, a niche that has not been previously included in F. oxysporum population genetics studies. Isolates were characterized using the DNA sequence of the translation elongation factor 1α gene. A diverse population of 26 sequence types was found, although two sequence types represented nearly two-thirds of the isolates studied. The sequence types were placed in different phylogenetic clades within F. oxysporum, and endophytic isolates were not monophyletic. Multiple sequence types were found in all plants, with an average of 4.2 per plant. The population compositions differed between the two fields but not between soil samples within each field. A certain degree of differentiation was observed between populations associated with different tomato cultivars, suggesting that the host genotype may affect the composition of plant-associated F. oxysporum populations. No clear patterns of genetic differentiation were observed between endophyte populations and soil populations, suggesting a lack of specialization of endophytic isolates. PMID:25304514

  17. The balance of planting and mortality in a street tree population

    Science.gov (United States)

    Lara A. Roman; John J. Battles; Joe R. McBride

    2013-01-01

    Street trees have aesthetic, environmental, human health, and economic benefits in urban ecosystems. Street tree populations are constructed by cycles of planting, growth, death, removal and replacement. The goals of this study were to understand how tree mortality and planting rates affect net population growth, evaluate the shape of the mortality curve, and assess...

  18. Competition between Plant-Populations with Different Rooting Depths. 2. Pot Experiments

    NARCIS (Netherlands)

    Berendse, F.

    1981-01-01

    In a previous paper in this series a model was proposed lor the competition between plant populations with different rooting depths. This model predicts that in mixtures of plant populations with different rooting depths the Relative Yield Total will exceed unity. Secondly it predicts that in these

  19. Wild Plant Species with Extremely Small Populations Require Conservation and Reintroduction in China

    Science.gov (United States)

    Hai Ren; Qianmei Zhang; Hongfang Lu; Hongxiao Liu; Qinfeng Guo; Jun Wang; Shuguang Jian; Hai’ou Bao

    2012-01-01

    China is exceptionally rich in biodiversity, with more than 30000 vascular plant species that include many endemic genera, species of ancient origin, and cultivated plants (Yang et al. 2005). Because of rapid economic development, population growth, pollution, and continuing resource exploitation, China’s plant diversity faces severe threats. According to the Chinese...

  20. Impact of tillage, plant population and mulches on phenological characters of maize

    International Nuclear Information System (INIS)

    Gul, B.; Khan, M.A.; Khan, H.

    2014-01-01

    Field experiments were conducted during 2006 and 2007 in Peshawar, using open pollinated maize variety Azam in RCB design having 3 factors viz., tillage, maize populations and mulches with split-split plot arrangements. Tillage levels (zero and conventional) were assigned to the main plots, populations (90000, 60000 and 30000 plants ha/sup -1/) to sub-plots and four types of mulches (weeds mulch, black plastic mulch, white plastic mulch and mungbean as living mulch), a hand weeding and a weedy check were allotted to sub-sub plots, respectively. Data were recorded on days to tasseling, days to silking, days to maturity, leaf area of maize plant-1 (cm/sub 2/) and plant height (cm). Tillage affected leaf area of maize, where zero tillage resulted lower leaf area of 4094 cm/sub 2/ compared to conventional tillage (4722 cm/sub 2/). Different levels of plant populations affected all the physiological parameters. Days to tasseling, silking and maturity were more in higher plant population as compared to medium and lower plant population. Similarly, minimum leaf area plant-1 was recorded in higher plant population (3894 cm/sub 2/) than medium and lower plant population of 4398 and 4932 cm/sub 2/, respectively. Maximum plant height was recorded in hand weeding treatment (173 cm). However, it was statistically at par with black plastic mulch (171 cm), followed by weeds mulch (162 cm) and white plastic mulch (161 cm) as compared to weedy check (152 cm). Based on two years study it is suggested that even if tillage options and plant populations are a part of the weed management program, it should not be used as a sole management tool, as both have a negative impact on the phenological parameters of maize which subsequently affected the final yield and must be integrated and supplemented with other control methods. (author)

  1. Site selection and evaluation for nuclear power plants with respect to population distribution

    International Nuclear Information System (INIS)

    1980-01-01

    This safety guide, relating population distribution to site selection and evaluation, for nuclear power plants, forms part of the IAEA's programme, referred to as the NUSS programme (Nuclear Safety Standards). The guide presents population distribution data, requirements, examples of site screening methods, and an overview of radiological impact assessment with respect to population distribution

  2. Optimum Design of Plasma Focus

    International Nuclear Information System (INIS)

    Ramos, Ruben; Gonzalez, Jose; Clausse, Alejandro

    2000-01-01

    The optimum design of Plasma Focus devices is presented based in a lumped parameter model of the MHD equations.Maps in the design parameters space are obtained, which determine the length and deuterium pressure required to produce a given neutron yield.Sensitivity analyses of the main effective numbers (sweeping efficiencies) was performed, and lately the optimum values were determined in order to set a basis for the conceptual design

  3. The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth.

    Science.gov (United States)

    Ford, Kevin R; Ness, Joshua H; Bronstein, Judith L; Morris, William F

    2015-10-01

    The impact of mutualists on a partner's demography depends on how they affect the partner's multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and simulations of long-term population dynamics to quantify the demographic impact of a guild of ant species on the plant Ferocactus wislizeni. The ants feed at the plant's extrafloral nectaries and attack herbivores attempting to consume reproductive organs. Ant-guarded plants produced significantly more fruit, but ants had no significant effect on individual growth or survival. After integrating ant effects across these vital rates, we found that projected population growth was not significantly different between unguarded and ant-guarded plants because population growth was only weakly influenced by differences in fruit production (though strongly influenced by differences in individual growth and survival). However, simulations showed that ants could positively affect long-term plant population dynamics through services provided during rare but important events (herbivore outbreaks that reduce survival or years of high seedling recruitment associated with abundant precipitation). Thus, in this seemingly clear example of mutualism, the interaction may actually yield no clear benefit to plant population growth, or if it does, may only do so through the actions of the ants during rare events. These insights demonstrate the value of taking a demographic approach to studying the consequences of mutualism.

  4. Ability of matrix models to explain the past and predict the future of plant populations.

    Science.gov (United States)

    McEachern, Kathryn; Crone, Elizabeth E.; Ellis, Martha M.; Morris, William F.; Stanley, Amanda; Bell, Timothy; Bierzychudek, Paulette; Ehrlen, Johan; Kaye, Thomas N.; Knight, Tiffany M.; Lesica, Peter; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Ticktin, Tamara; Valverde, Teresa; Williams, Jennifer I.; Doak, Daniel F.; Ganesan, Rengaian; Thorpe, Andrea S.; Menges, Eric S.

    2013-01-01

    Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models.

  5. Ability of matrix models to explain the past and predict the future of plant populations.

    Science.gov (United States)

    Crone, Elizabeth E; Ellis, Martha M; Morris, William F; Stanley, Amanda; Bell, Timothy; Bierzychudek, Paulette; Ehrlén, Johan; Kaye, Thomas N; Knight, Tiffany M; Lesica, Peter; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F; Ticktin, Tamara; Valverde, Teresa; Williams, Jennifer L; Doak, Daniel F; Ganesan, Rengaian; McEachern, Kathyrn; Thorpe, Andrea S; Menges, Eric S

    2013-10-01

    Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. © 2013 Society for Conservation Biology.

  6. Socio environmental policy and populational resettlement in hydropower plants

    International Nuclear Information System (INIS)

    Regini Nuti, Mirian; Feitosa Garcia, Marcia

    2003-01-01

    This paper aims to discuss the resettlement process caused by hydropower plants considering the Brazilian Power Sector ongoing context It is based on the analysis of the hydropower plants that started operation phase in the last tem years There are 17 projects provoking the displacement of 21000 families The paper presents the resettlement modalities used in these projects Finally, the main aspects of the resettlement process in the last decade are focused in order to contribute to the Brazilian Power Sector Resettlement Guidelines improvement and actualization

  7. Effect of plant populations on the productivity of plantain and ...

    African Journals Online (AJOL)

    Two plantain-cassava intercropping experiments were conducted at the Teaching and Research Farm of Obafemi Awolowo University, Ile–Ife. Each experiment was planted in a 2 x 2 factorial involving four mixture proportions arranged in Randomized Complete Block design with four replications. Growth, crop yields and ...

  8. Plant functional traits as determinants of population stability

    Czech Academy of Sciences Publication Activity Database

    Májeková, M.; de Bello, Francesco; Doležal, Jiří; Lepš, Jan

    2014-01-01

    Roč. 95, č. 9 (2014), s. 2369-2374 ISSN 0012-9658 R&D Projects: GA ČR GA13-17118S Institutional support: RVO:67985939 ; RVO:60077344 Keywords : biomass * fertilizaiton * plant functional traits Subject RIV: EH - Ecology, Behaviour Impact factor: 4.656, year: 2014

  9. Bud initiation and optimum harvest date in Brussels sprouts

    NARCIS (Netherlands)

    Everaarts, A.P.; Sukkel, W.

    1999-01-01

    For six cultivars of Brussels sprouts (Brassica oleracea var. gemmifera) with a decreasing degree of earliness, or optimum harvest date, the time of bud initiation was determined during two seasons. Fifty percent of the plants had initiated buds between 60 and 75 days after planting (DAP) in 1994

  10. The Genetic Basis of Plant Architecture in 10 Maize Recombinant Inbred Line Populations.

    Science.gov (United States)

    Pan, Qingchun; Xu, Yuancheng; Li, Kun; Peng, Yong; Zhan, Wei; Li, Wenqiang; Li, Lin; Yan, Jianbing

    2017-10-01

    Plant architecture is a key factor affecting planting density and grain yield in maize ( Zea mays ). However, the genetic mechanisms underlying plant architecture in diverse genetic backgrounds have not been fully addressed. Here, we performed a large-scale phenotyping of 10 plant architecture-related traits and dissected the genetic loci controlling these traits in 10 recombinant inbred line populations derived from 14 diverse genetic backgrounds. Nearly 800 quantitative trait loci (QTLs) with major and minor effects were identified as contributing to the phenotypic variation of plant architecture-related traits. Ninety-two percent of these QTLs were detected in only one population, confirming the diverse genetic backgrounds of the mapping populations and the prevalence of rare alleles in maize. The numbers and effects of QTLs are positively associated with the phenotypic variation in the population, which, in turn, correlates positively with parental phenotypic and genetic variations. A large proportion (38.5%) of QTLs was associated with at least two traits, suggestive of the frequent occurrence of pleiotropic loci or closely linked loci. Key developmental genes, which previously were shown to affect plant architecture in mutant studies, were found to colocalize with many QTLs. Five QTLs were further validated using the segregating populations developed from residual heterozygous lines present in the recombinant inbred line populations. Additionally, one new plant height QTL, qPH3 , has been fine-mapped to a 600-kb genomic region where three candidate genes are located. These results provide insights into the genetic mechanisms controlling plant architecture and will benefit the selection of ideal plant architecture in maize breeding. © 2017 American Society of Plant Biologists. All Rights Reserved.

  11. Using soil seed banks to assess temporal patterns of genetic variation in invasive plant populations

    OpenAIRE

    Fennell, Mark; Gallagher, Tommy; Vintro, Luis Leon; Osborne, Bruce

    2014-01-01

    Most research on the genetics of invasive plant species has focused on analyzing spatial differences among existing populations. Using a long-established Gunnera tinctoria population from Ireland, we evaluated the potential of using plants derived from seeds associated with different soil layers to track genetic variation through time. This species and site were chosen because (1) G. tinctoria produces a large and persistent seed bank; (2) it has been present in this locality, Sraheens, for ∼...

  12. Effect of plant population and N fertilizer on the growth and yield of ...

    African Journals Online (AJOL)

    Responses of bambara groundnut (Vigna subterranea (L.) Verdc) to 3 levels of fertilizer N (0, 50, and 100 kg N/ha) and seven plant populations (55555, 63492, 74074, 88888, 111111, 148148 and 222222 plants/ha) were studied under field conditions in Nsukka, Nigeria. The experimental design was a randomized ...

  13. Competition between Plant-Populations with Different Rooting Depths. 1. Theoretical Considerations

    NARCIS (Netherlands)

    Berendse, F.

    1979-01-01

    As an extension of De Wit's competition theory a theoretical description has been developed of competition between plant populations with different rooting depths. This model shows that in mixtures of plants with different rooting depths the value of the Relative Yield Total can be expected to

  14. Competition Between Plant Populations with Different Rooting Depths I. Theoretical Considerations

    NARCIS (Netherlands)

    Berendse, Frank

    1979-01-01

    As an extension of De Wit’s competition theory a theoretical description has been developed of competition between plant populations with different rooting depths. This model shows that in mixtures of plants with different rooting depths the value of the Relative Yield Total can be expected to

  15. Occupational hazard evaluation of working population in a select automotive industrial plant.

    Science.gov (United States)

    Wójcik, Alicja; Borzecki, Zdzisław; Kowalska, Edyta; Borzecki, Andrzej

    2004-01-01

    The research was conducted in the selected vehicle industry plant. Work conditions were assessed on the assembly line by measuring chemical and physical factors. Exposure to noise in the investigated plant exceeded the values of permissible standards. The pollution on the posts did not exceed the standards except singular concentrations. While assessing the values of chemical factors concentration, no toxicological danger was revealed in the investigated population. The work conditions of the investigated plant did not create the danger of professional diseases.

  16. Optimum Safety Levels for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    2005-01-01

    Optimum design safety levels for rock and cube armoured rubble mound breakwaters without superstructure are investigated by numerical simulations on the basis of minimization of the total costs over the service life of the structure, taking into account typical uncertainties related to wave...... statistics and structure response. The study comprises the influence of interest rate, service lifetime, downtime costs and damage accumulation. Design limit states and safety classes for breakwaters are discussed. The results indicate that optimum safety levels are somewhat higher than the safety levels...

  17. Assessing the impact of power plant mortality on the compensatory reserve of fish populations

    International Nuclear Information System (INIS)

    Goodyear, C.P.

    1977-01-01

    A technique is presented to quantify the concepts of compensation and compensatory reserve in exploited fish populations. The technique was used to examine the impact of power plant mortality on a hypothetical striped bass population. Power plant mortality had a more severe impact on the compensation ratio and compensatory reserve for an exploited stock. The technique can be applied to determine a critical compensation ratio which could serve as a standard against which additional sources of mortality, such as those caused by power plants, could be measured

  18. Genetic variability in chronic irradiated plant populations - Polymorphism and activity of antioxidant enzymes in chronic irradiated plant populations

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, Polina Y.; Geras' kin, Stanislav A. [Russian Institute of Agricultural Radiology and Agroecology, 249030, Obninsk, Kievskoe shosse 109 km (Russian Federation)

    2014-07-01

    Introduction: The gene pool of natural population is constantly changing in order to provide the greatest fitness at this time. Ability of population to adapt to changing environmental conditions depends on genetic polymorphism of traits which are operates by selection. Chronic stress exposure can change amount or structure intra-population variability. Therefore, it is necessary to analyze the relationships between genetic polymorphism and stress factors, such as radiation exposure. This studies my assist in the development of new bio-indication methods. Materials and methods: Studying sites: Bryansk region is the most contaminated region of Russia as a result of Chernobyl accident. The initial activity by {sup 137}Cs on this territory reached 1 MBq/m{sup 2} above surface. Our study conducted in several districts of Bryansk region, which are characterized the most dose rate. Experimental sites similar to climate characteristics, stand of trees is homogeneous, pine trees take up a significant part of phytocenosis. Heavy metals content in soils and cones be within background. Dose rates vary from 0.14 to 130 mGy/year. Object: Pinus sylvestris L.,the dominant tree species in North European and Asian boreal forests. Scots pine has a long maturation period (18-20 month), which means that significant DNA damage may accumulate in the undifferentiated stem cells, even at low doses (or dose rates) during exposure to low concentrations of contaminants Isozyme analysis: We evaluated isozyme polymorphism of three antioxidant enzymes: superoxide dismutase, glutatione reductase and glutatione peroxidase. Analysis of enzymes activities: We chose key enzymes of antioxidant system for this experiment: superoxide dismutase, catalase and peroxidase. Results and conclusions: We estimated frequency of each allele in reference and experimental populations. based It was showed that frequency of rare alleles increase in chronic irradiated populations, i.e. increase the sampling variance

  19. Baselines to detect population stability of the threatened alpine plant Packera franciscana (Asteraceae)

    Science.gov (United States)

    James F. Fowler; Carolyn Hull Sieg; Shaula Hedwall

    2015-01-01

    Population size and density estimates have traditionally been acceptable ways to track species’ response to changing environments; however, species' population centroid elevation has recently been an equally important metric. Packera franciscana (Greene) W.A. Weber and A. Love (Asteraceae; San Francisco Peaks ragwort) is a single mountain endemic plant found only...

  20. Optimum target thickness for polarimeters

    International Nuclear Information System (INIS)

    Sitnik, I.M.

    2003-01-01

    Polarimeters with thick targets are a tool to measure the proton polarization. But the question about the optimum target thickness is still the subject of discussion. An attempt to calculate the most common parameters concerning this problem, in a few GeV region, is made

  1. Relative population exposures from coal-fired and nuclear power plants in India

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, T.V.; Lalit, B.Y.; Mishra, U.C.

    1987-01-01

    Coal combustion for electric power generation results in dispersal of fly ash, and hence an additional radiation dose to the population living in the neighbourhood of the coal-fired power plants due to natural radioactivity present in coal. The radiation hazards of coal based and nuclear power plants operating in India are given. The dose commitments to the population living within an 88.5 km radius of the thermal and nuclear power plants in India have been computed using the method outlined in an ORNL report. The estimated dose rates for these two types of power plant were compared. The present study shows that the radiation dose from coal-fired and nuclear power plants are comparable.

  2. Effect of plant-animal interactions on individual performance and population dynamics of Scorzonera hispanica

    OpenAIRE

    Červenková, Zita

    2016-01-01

    The population dynamics of plants with regard to plant-animal interactions is a remarkably complex topic. To look into how individual life stages are influenced in different directions by various animals is beyond the scope of a single paper. For each of the studies described below, I and my co-authors attempted to collect data that would cover as much of the plant life cycle as possible, focusing on interactions between plants and different animals during the flowering period and their conse...

  3. Siting of nuclear power plants in densely populated countries

    International Nuclear Information System (INIS)

    Togo, Y.

    1981-01-01

    In evaluating the safety of reactor siting, three typical approaches can be applied; the deterministic approach, the probabilistic approach and the combined approach. In regard to a risk associated with siting, the design of a reactor has to do with both individual and societal risk, while exclusion distance mainly has to do with individual risk, and surrounding population primarily has to do with societal risk. Consequently, in a densely populated area, more attention should be paid to societal risk. There are many reactor sites in the world which can be described as concentrated siting. Although concentrated siting has a lot of merits, such as reducing the construction cost or maintenance cost of reactors, more careful consideration should be paid to safety-related matters of such concentrated reactors because the risk to the individual from accidents caused by concentrated reactors is larger than that from a single reactor. As for the recent controversial issue concerning siting criteria, it appears that the present international consensus on siting philosophy is still valid after the TMI accident. (author)

  4. Insect herbivores drive real-time ecological and evolutionary change in plant populations.

    Science.gov (United States)

    Agrawal, Anurag A; Hastings, Amy P; Johnson, Marc T J; Maron, John L; Salminen, Juha-Pekka

    2012-10-05

    Insect herbivores are hypothesized to be major factors affecting the ecology and evolution of plants. We tested this prediction by suppressing insects in replicated field populations of a native plant, Oenothera biennis, which reduced seed predation, altered interspecific competitive dynamics, and resulted in rapid evolutionary divergence. Comparative genotyping and phenotyping of nearly 12,000 O. biennis individuals revealed that in plots protected from insects, resistance to herbivores declined through time owing to changes in flowering time and lower defensive ellagitannins in fruits, whereas plant competitive ability increased. This independent real-time evolution of plant resistance and competitive ability in the field resulted from the relaxation of direct selective effects of insects on plant defense and through indirect effects due to reduced herbivory on plant competitors.

  5. Anomalous dependence of population growth on the birth rate in the plant-herbivore system

    International Nuclear Information System (INIS)

    Cui, Xue M.; Han, Seung K.; Chung, Jean S.

    2010-01-01

    We performed a simulation of the two-species plant-herbivore system by using the agent-based NetLogo program and constructed a dynamic model of populations consistent with the simulation results. The dynamic model is a three-dimensional system including the mean energy of the herbivore in addition to two variables denoting the populations of plants and herbivores. A steady-state analysis of the dynamic model shows that the dependence of the herbivore population on the birth and the death rates observed from the agent model is consistent with the prediction of the dynamic model. Especially, the anomalous dependence of the herbivore population on the birth rate, where the population decreases with the birth rate for small death rate, is consistently explained by a phase plane analysis of the dynamic model.

  6. Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots

    Science.gov (United States)

    Picard, Christine; Bosco, Marco

    2008-01-01

    Several soil microorganisms colonizing roots are known to naturally promote the health of plants by controlling a range of plant pathogens, including bacteria, fungi, and nematodes. The use of theses antagonistic microorganisms, recently named plant-probiotics, to control plant-pathogenic fungi is receiving increasing attention, as they may represent a sustainable alternative to chemical pesticides. Many years of research on plant-probiotic microorganisms (PPM) have indicated that fluorescent pseudomonads producing antimicrobial compounds are largely involved in the suppression of the most widespread soilborne pathogens. Phenotype and genotype analysis of plant-probiotic fluorescent pseudomonads (PFP) have shown considerable genetic variation among these types of strains. Such variability plays an important role in the rhizosphere competence and the biocontrol ability of PFP strains. Understanding the mechanisms by which genotypic and phenotypic diversity occurs in natural populations of PFP could be exploited to choose those agricultural practices which best exploit the indigenous PFP populations, or to isolate new plant-probiotic strains for using them as inoculants. A number of different methods have been used to study diversity within PFP populations. Because different resolutions of the existing microbial diversity can be revealed depending on the approach used, this review first describes the most important methods used for the assessment of fluorescent Pseudomonas diversity. Then, we focus on recent data relating how differences in genotypic and phenotypic diversity within PFP communities can be attributed to geographic location, climate, soil type, soil management regime, and interactions with other soil microorganisms and host plants. It becomes evident that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PFP populations.

  7. Optimum design of steel structures

    CERN Document Server

    Farkas, József

    2013-01-01

    This book helps designers and manufacturers to select and develop the most suitable and competitive steel structures, which are safe, fit for production and economic. An optimum design system is used to find the best characteristics of structural models, which guarantee the fulfilment of design and fabrication requirements and minimize the cost function. Realistic numerical models are used as main components of industrial steel structures. Chapter 1 containts some experiences with the optimum design of steel structures Chapter 2 treats some newer mathematical optimization methods. Chapter 3 gives formulae for fabrication times and costs. Chapters 4 deals with beams and columns. Summarizes the Eurocode rules for design. Chapter 5 deals with the design of tubular trusses. Chapter 6 gives the design of frame structures and fire-resistant design rules for a frame. In Chapters 7 some minimum cost design problems of stiffened and cellular plates and shells are worked out for cases of different stiffenings and loads...

  8. Use of plants in oral health care by the population of Mahajanga, Madagascar.

    Science.gov (United States)

    Ranjarisoa, Lala Nirina; Razanamihaja, Noëline; Rafatro, Herintsoa

    2016-12-04

    The use of medicinal plants to address oral health problems is not well documented in Madagascar, yet the country is full of endemic flora. The aim of this study was to collect information on the use of plants in the region of Mahajanga, Madagascar, for the treatments of oral diseases mainly tooth decay. The ethnobotanical survey with respect to the use of plants for curing dental problems was carried out in 2012. A cluster sampling at three levels was applied when choosing the study sites. The target population was made up of heads of household. The following data were collected from a semi-structured questionnaire: name of plants, part used, mode of preparation, and administration. The Informant Consensus Factor and Fidelity Level indexes were calculated for each condition treated and used plants. The Results revealed that 93 per cent of the targeted population has used plants to calm dental pain, whereas 44.2% have reported using plants due to financial problems. About 65 species of plants are commonly used for oral health care and 63 of them treated caries. Cajanus cajan (L.) Millsp. was the most plant used. It was mostly used in crushed form of 5 to 9 leaves which were prepared and placed directly on the affected oral part or in the tooth cavity. In general, the treatment lasted about 5 days or minus. The ICF were 0.83 for caries and 0.81 for periodontal diseases. This ethnobotanical survey will serve as database for further phytochemical and pharmacological study of plants in order to identify their active components and advise the population on the most effective administration. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Causes and consequences of complex population dynamics in an annual plant, Cardamine pensylvanica

    Energy Technology Data Exchange (ETDEWEB)

    Crone, E.E.

    1995-11-08

    The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.

  10. Alarming plant dieback in the Outeniquas : is this an indication of global warming? Monitoring plant populations

    CSIR Research Space (South Africa)

    Rebelo, T

    2009-03-01

    Full Text Available for the Outeniquas do predict increased precipitation in summer. But we don’t know. Only in 20 years will we be able to look back and decide. At this stage it is safer to claim that the plants responded markedly to the exceptional weather conditions. Whether... these weather conditions are indicative of climate changes to come only time will tell. But it is only by documenting the responses of plants to these extreme events that we will get a clear idea of what might happen as our climate changes. Then we...

  11. Nuclear power plant site evaluation using site population-meterology factor

    International Nuclear Information System (INIS)

    Rho, B.H.; Kang, C.H.

    1982-01-01

    In this paper, as a site evaluation technique, SPNF(Site Population Neteorology Factor) which is modified from SPF(Site Population Factor) of the USNRC model, is defined from site population and meteorology data in order to consider the radiological impacts to the population at large from the atmospheric dispersion of the radioactive effluents released during routine plant operation as well as accidental conditions. The SPMF model proved its propriety from the comparison of SPMF and SPF for Kori site. The relative suitability of Korean sites to the U.S. sites have been also examined using SPF. (Author)

  12. How to conserve threatened Chinese plant species with extremely small populations?

    Directory of Open Access Journals (Sweden)

    Sergei Volis

    2016-02-01

    Full Text Available The Chinese flora occupies a unique position in global plant diversity, but is severely threatened. Although biodiversity conservation in China has made significant progress over the past decades, many wild plant species have extremely small population sizes and therefore are in extreme danger of extinction. The concept of plant species with extremely small populations (PSESPs, recently adopted and widely accepted in China, lacks a detailed description of the methodology appropriate for conserving PSESPs. Strategies for seed sampling, reintroduction, protecting PSESP locations, managing interactions with the local human population, and other conservation aspects can substantially differ from those commonly applied to non-PSESPs. The present review is an attempt to provide a detailed conservation methodology with realistic and easy-to-follow guidelines for PSESPs in China.

  13. Herbivory and growth in terrestrial and aquatic populations of amphibious stream plants

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Jacobsen, Dean

    2002-01-01

    1. Many amphibious plant species grow in the transition between terrestrial and submerged vegetation in small lowland streams. We determined biomass development, leaf turnover rate and invertebrate herbivory during summer in terrestrial and aquatic populations of three amphibious species...... production (average 1.2-5.1%) than aquatic populations (2.9-17.3%), while the same plant dry mass was consumed per unit ground area. 3. Grazing loss increased linearly with leaf age apart from the youngest leaf stages. Grazing loss during the lifetime of leaves was therefore 2.4-3.1 times higher than mean...... apparent loss to standing leaves of all ages. The results imply that variation in density of grazers relative to plant production can account for differences in grazing impact between terrestrial and aquatic populations, and that fast leaf turnover keeps apparent grazing damage down. 4. We conclude...

  14. Population dynamics of bacteria involved in enhanced biological phosphorus removal in Danish wastewater treatment plants.

    Science.gov (United States)

    Mielczarek, Artur Tomasz; Nguyen, Hien Thi Thu; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2013-03-15

    The enhanced biological phosphorus removal (EBPR) process is increasingly popular as a sustainable method for removal of phosphorus (P) from wastewater. This study consisted of a comprehensive three-year investigation of the identity and population dynamics of polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in 28 Danish municipal wastewater treatment plants with nutrient removal. Fluorescence in situ hybridization was applied to quantify ten probe-defined populations of PAO and GAO that in total constituted a large fraction (30% on average) of the entire microbial community targeted by the EUBmix probes. Two PAO genera, Accumulibacter and Tetrasphaera, were very abundant in all EBPR plants (average of 3.7% and 27% of all bacteria, respectively), and their abundance was relatively stable in the Danish full-scale plants without clear temporal variations. GAOs were occasionally present in some plants (Competibacter in 11 plants, Defluviicoccus in 6 plants) and were consistent in only a few plants. This shows that these were not core species in the EBPR communities. The total GAO abundance was always lower than that of Accumulibacter. In plants without EBPR design, the abundance of PAO and GAO was significantly lower. Competibacter correlated in general with high fraction of industrial wastewater. In specific plants Accumulibacter correlated with high C/P ratio of the wastewater and Tetrasphaera with high organic loading. Interestingly, the relative microbial composition of the PAO/GAO species was unique to each plant over time, which gives a characteristic plant-specific "fingerprint". Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Host plant use drives genetic differentiation in syntopic populations of Maculinea alcon

    DEFF Research Database (Denmark)

    Tartally, András; Kelager, Andreas; Fürst, Matthias Alois

    2016-01-01

    The rare socially parasitic butterfly Maculinea alcon occurs in two forms, which are characteristic of hygric or xeric habitats and which exploit different host plants and host ants. The status of these two forms has been the subject of considerable controversy. Populations of the two forms...... on different host plants, each with a distinct flowering phenology, providing a temporal rather than spatial barrier to gene flow....

  16. Population genetic analysis reveals barriers and corridors for gene flow within and among riparian populations of a rare plant.

    Science.gov (United States)

    Hevroy, Tanya H; Moody, Michael L; Krauss, Siegfried L

    2018-02-01

    Landscape features and life-history traits affect gene flow, migration and drift to impact on spatial genetic structure of species. Understanding this is important for managing genetic diversity of threatened species. This study assessed the spatial genetic structure of the rare riparian Grevillea sp. Cooljarloo (Proteaceae), which is restricted to a 20 km 2 region impacted by mining in the northern sandplains of the Southwest Australian Floristic Region, an international biodiversity hotspot. Within creek lines and floodplains, the distribution is largely continuous. Models of dispersal within riparian systems were assessed by spatial genetic analyses including population level partitioning of genetic variation and individual Bayesian clustering. High levels of genetic variation and weak isolation by distance within creek line and floodplain populations suggest large effective population sizes and strong connectivity, with little evidence for unidirectional gene flow as might be expected from hydrochory. Regional clustering of creek line populations and strong divergence among creek line populations suggest substantially lower levels of gene flow among creek lines than within creek lines. There was however a surprising amount of genetic admixture in floodplain populations, which could be explained by irregular flooding and/or movements by highly mobile nectar-feeding bird pollinators. Our results highlight that for conservation of rare riparian species, avoiding an impact to hydrodynamic processes, such as water tables and flooding dynamics, may be just as critical as avoiding direct impacts on the number of plants.

  17. Conservation state of populations of rare plant species in highly transformed meadow steppes of Southern Opillya

    Directory of Open Access Journals (Sweden)

    I. I. Dmytrash-Vatseba

    2016-09-01

    Full Text Available Degradation of natural habitats causes rapid extinction of rare plant populations. The diversity of rare plant species in the meadow steppes of Southern Opillya (Western Ukraine depends strongly on patch area, pasture digression of vegetation and a variety of eco-coenotical conditions. The main threats for the rare components of the meadow steppe flora are reduction of habitat and overgrazing. Spatial connections between sites are unable to support a constant rare plant population. The analysis of the composition of rare plant meadow-steppe species indicated that habitats with similar rare species composition usually have similar parameters of area, stages of pasture digression and eco-coenotical conditions. Spatial connectivity of patches does not ensure species similarity of rare components of the flora. Rare plant species were grouped according to their preferences for habitat , area and condition. In small patches subject to any stage of pasture digression grow populations of Adonis vernalis L., Pulsatilla patens (L. Mill., P. grandis Wender., Stipa capillata L., S. рennata L., Chamaecytisus blockianus (Pawł. Klásková etc. On the contrary, populations of other species (Carlina onopordifolia Besser. ex Szafer., Kuecz. et Pawł., Adenophora liliifolia (L. Ledeb. ex A. DC., Crambe tataria Sebeók, Euphorbia volhynica Besser ex Racib., Stipa tirsa Stev. etc. prefer large habitats, not changed by pasture digression. Prevention of reduction of rare species diversity requires preservation (also extension of patch area and regulation of grazing intensity.

  18. Lead and zinc accumulation and tolerance in populations of six wetland plants

    Energy Technology Data Exchange (ETDEWEB)

    Deng, H. [Biology Department and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon, Hong Kong (China); Department of Environmental Science and Technology, East China Normal University, Shanghai (China); Ye, Z.H. [Biology Department and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon, Hong Kong (China); School of Life Sciences, Zhongshan (Sun Yat-sen) University, Guangzhou 510275 (China); Wong, M.H. [Biology Department and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon, Hong Kong (China)]. E-mail: mhwong@hkbu.edu.hk

    2006-05-15

    Wetland plants such as Typha latifolia and Phragmites australis have been indicated to show a lack of evolution of metal tolerance in metal-contaminated populations. The aim of the present study is to verify whether other common wetland plants such as Alternanthera philoxeroides and Beckmannia syzigachne, also possess the same characteristics. Lead and zinc tolerances in populations of six species collected from contaminated and clean sites were examined by hydroponics. In general, the contaminated populations did not show higher metal tolerance and accumulation than the controls. Similar growth responses and tolerance indices in the same metal treatment solution between contaminated and control populations suggest that metal tolerance in wetland plants are generally not further evolved by contaminated environment. The reasons may be related to the special root anatomy in wetland plants, the alleviated metal toxicity by the reduced rooting conditions and the relatively high innate metal tolerance in some species. - Populations from metal contaminated sites did not have significantly higher metal tolerance indices.

  19. Lead and zinc accumulation and tolerance in populations of six wetland plants

    International Nuclear Information System (INIS)

    Deng, H.; Ye, Z.H.; Wong, M.H.

    2006-01-01

    Wetland plants such as Typha latifolia and Phragmites australis have been indicated to show a lack of evolution of metal tolerance in metal-contaminated populations. The aim of the present study is to verify whether other common wetland plants such as Alternanthera philoxeroides and Beckmannia syzigachne, also possess the same characteristics. Lead and zinc tolerances in populations of six species collected from contaminated and clean sites were examined by hydroponics. In general, the contaminated populations did not show higher metal tolerance and accumulation than the controls. Similar growth responses and tolerance indices in the same metal treatment solution between contaminated and control populations suggest that metal tolerance in wetland plants are generally not further evolved by contaminated environment. The reasons may be related to the special root anatomy in wetland plants, the alleviated metal toxicity by the reduced rooting conditions and the relatively high innate metal tolerance in some species. - Populations from metal contaminated sites did not have significantly higher metal tolerance indices

  20. Effects of long-term chronic exposure to radionuclides in plant populations

    International Nuclear Information System (INIS)

    Geras'kin, S.; Evseeva, T.; Oudalova, A.

    2013-01-01

    The results of field studies carried out on different plant species (winter rye and wheat, spring barley, oats, Scots pine, wild vetch, crested hairgrass) in various radioecological situations (nuclear weapon testing, the Chernobyl accident, uranium and radium processing) to investigate the effects of long-term chronic exposure to radionuclides are discussed. Plant populations growing in areas with relatively low levels of pollution are characterized by an increased level of both cytogenetic disturbances and genetic diversity. Although ionizing radiation causes primary damage at the molecular level, there are emergent effects at the level of populations, non-predictable from the knowledge of elementary mechanisms of cellular effects formation. Accumulation of cellular alterations may afterward influence biological parameters important for populations such as health and reproduction. Presented data provide evidence that in plant populations inhabiting heavily contaminated territories cytogenetic damage could be accompanied by a decrease in reproductive capacity. However, in less contaminated sites, because of the scarcity of data available, a steady relationship between cytogenetic effects and reproductive capacity was not revealed. Under radioactive contamination of the plant's environment, a population's resistance to exposure may increase. However, there are radioecological situations where an enhanced radioresistance has not evolved or has not persisted

  1. Disjunct populations of European vascular plant species keep the same climatic niches

    DEFF Research Database (Denmark)

    Wasof, Safaa; Lenoir, Jonathan; Aarrestad, Per Arild

    2015-01-01

    separated for thousands of years. Location: European Alps and Fennoscandia. Methods: Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly......Aim: Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been...... to be largely valid for arctic-alpine plants....

  2. Model calculations of the influence of population distribution on the siting of nuclear power plants

    International Nuclear Information System (INIS)

    Nielsen, F.; Walmod-Larsen, O.

    1984-02-01

    This report was prepared for a working group established in April 1981 by the Danish Environmental Protection Agency with the task of investigating siting problems of nuclear power stations in Denmark. The purpose of the working group was to study the influence of the population density around a site on nuclear power safety. The importance of emergency planning should be studied as well. In this model study two specific accident sequences were simulated on a 1000 MWe nuclear power plant. The plant was assumed to be placed in the center of two different model population distributions. The concequences for the two population distributions from the two accidents were calculated for the most frequent weather conditions. Doses to individuals were calculated for the bone marrow, lungs, gastrointestinal tract, thyroidea and for the whole body. The collective whole body doses were also calculated for the two populations considered. (author)

  3. Low doses of six toxicants change plant size distribution in dense populations of Lactuca sativa.

    Science.gov (United States)

    Belz, Regina G; Patama, Marjo; Sinkkonen, Aki

    2018-08-01

    Toxicants are known to have negligible or stimulatory, i.e. hormetic, effects at low doses below those that decrease the mean response of a plant population. Our earlier observations indicated that at such low toxicant doses the growth of very fast- and slow-growing seedlings is selectively altered, even if the population mean remains constant. Currently, it is not known how common these selective low-dose effects are, whether they are similar among fast- and slow-growing seedlings, and whether they occur concurrently with hormetic effects. We tested the response of Lactuca sativa in complete dose-response experiments to six different toxicants at doses that did not decrease population mean and beyond. The tested toxicants were IAA, parthenin, HHCB, 4-tert-octylphenol, glyphosate, and pelargonic acid. Each experiment consisted of 14,400-16,800 seedlings, 12-14 concentrations, 24 replicates per concentration and 50 germinated seeds per replicate. We analyzed the commonness of selective low-dose effects and explored if toxic effects and hormetic stimulation among fast- and slow-growing individuals occurred at the same concentrations as they occur at the population level. Irrespective of the observed response pattern and toxicant, selective low-dose effects were found. Toxin effects among fast-growing individuals usually started at higher doses compared to the population mean, while the opposite was found among slow-growing individuals. Very low toxin exposures tended to homogenize plant populations due to selective effects, while higher, but still hormetic doses tended to heterogenize plant populations. Although the extent of observed size segregation varied with the specific toxin tested, we conclude that a dose-dependent alteration in size distribution of a plant population may generally apply for many toxin exposures. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Uncoupling the effects of seed predation and seed dispersal by granivorous ants on plant population dynamics.

    Directory of Open Access Journals (Sweden)

    Xavier Arnan

    Full Text Available Secondary seed dispersal is an important plant-animal interaction, which is central to understanding plant population and community dynamics. Very little information is still available on the effects of dispersal on plant demography and, particularly, for ant-seed dispersal interactions. As many other interactions, seed dispersal by animals involves costs (seed predation and benefits (seed dispersal, the balance of which determines the outcome of the interaction. Separate quantification of each of them is essential in order to understand the effects of this interaction. To address this issue, we have successfully separated and analyzed the costs and benefits of seed dispersal by seed-harvesting ants on the plant population dynamics of three shrub species with different traits. To that aim a stochastic, spatially-explicit individually-based simulation model has been implemented based on actual data sets. The results from our simulation model agree with theoretical models of plant response dependent on seed dispersal, for one plant species, and ant-mediated seed predation, for another one. In these cases, model predictions were close to the observed values at field. Nonetheless, these ecological processes did not affect in anyway a third species, for which the model predictions were far from the observed values. This indicates that the balance between costs and benefits associated to secondary seed dispersal is clearly related to specific traits. This study is one of the first works that analyze tradeoffs of secondary seed dispersal on plant population dynamics, by disentangling the effects of related costs and benefits. We suggest analyzing the effects of interactions on population dynamics as opposed to merely analyzing the partners and their interaction strength.

  5. Perceptions of Medicinal Plant Use Amongst the Hispanic Population in the St. Louis Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Kim M. Grafford

    2016-10-01

    Full Text Available Introduction: Medicinal plant use in the United States has increased as reported by the National Center of Complementary and Integrative Health and U.S. Census Bureau.However, little is known about how many minority groups in the United States use medicinal plants.There is a rise in the Hispanic population; a community with a steep tradition of medicinal plant use, in the U.S., so understanding the perceptions of medicinal plant use is useful to healthcare providers. Methods: A survey was designed to gauge a better understanding of the perceptions of medicinal plant use amongst Latino patients with varying education levels who reside in the St. Louis Metropolitan Area. Survey questions highlighted the perceptions of medicinal plants use, patient communication regarding medicinal plant use with healthcare providers (pharmacists and doctors, and the impact the education level has on medicinal plant use. Results: Surveys were distributed to six different investigational sites around the St. Louis Metropolitan Area from August 2015 to December 2015. Survey respondents identified 45 different plants/herbs that they currently use or had used at some point in their life. Those with higher levels of education had varying opinions on medicinal plant use with their current practices. Conclusion: The participants’ high interest in the use of medicinal plants exemplifies the need for enhanced communication between patients and healthcare professionals about medicinal plant use. However, it was hard to determine whether the participants’ level of education had any direct relationship to this use. Conflict of Interest None   Type: Original Research

  6. Population genetics and the evolution of geographic range limits in an annual plant.

    Science.gov (United States)

    Moeller, David A; Geber, Monica A; Tiffin, Peter

    2011-10-01

    Abstract Theoretical models of species' geographic range limits have identified both demographic and evolutionary mechanisms that prevent range expansion. Stable range limits have been paradoxical for evolutionary biologists because they represent locations where populations chronically fail to respond to selection. Distinguishing among the proposed causes of species' range limits requires insight into both current and historical population dynamics. The tools of molecular population genetics provide a window into the stability of range limits, historical demography, and rates of gene flow. Here we evaluate alternative range limit models using a multilocus data set based on DNA sequences and microsatellites along with field demographic data from the annual plant Clarkia xantiana ssp. xantiana. Our data suggest that central and peripheral populations have very large historical and current effective population sizes and that there is little evidence for population size changes or bottlenecks associated with colonization in peripheral populations. Whereas range limit populations appear to have been stable, central populations exhibit a signature of population expansion and have contributed asymmetrically to the genetic diversity of peripheral populations via migration. Overall, our results discount strictly demographic models of range limits and more strongly support evolutionary genetic models of range limits, where adaptation is prevented by a lack of genetic variation or maladaptive gene flow.

  7. Evaluation Of The Exclusion And Low Population Areas Around A Nuclear Power Plant

    International Nuclear Information System (INIS)

    Tawfik, F.S.

    2011-01-01

    Being adjacent to the nuclear power plant (NPP) the exclusion area (EA) is the area of greatest importance. It essentially defines a buffer zone where the public has no access. It helps to define the fenced plant area, the site area and the public area. Also, the low population area is the area immediately surrounding the exclusion area near a licensed reactor in terms of public safety and the ability of residents to get away from the plant in an emergency. This study clarifies their significance and reviews the international approach on them. Assuming the nuclear power plant site at the north coast of Egypt, the exclusion area and low population area are determined according to CFR (2002). In this method, a maximum possible amount of radioactivity release (called a source term) should be assumed. The boiling water reactor (BWR) with a power 1000 MW was used to carry the calculation and assuming a severe loss of coolant accident with meltdown of reactor. The site specific data have been collected, investigated and processed. The effect of the degree of atmospheric stability and building width of the plant were examined. The proceeding factors that control the determination of exclusion area and low population area should be taken into consideration in the site evaluation stage and design basis of NPP to set a minimum distances for them

  8. Effect Of Plant Population On Yield Of Maize And Climbing Beans ...

    African Journals Online (AJOL)

    A field experiment was conducted at Kachwekano near Kabale town for two seasons: second rains of 1996 (1996b) and first rains of 1997 (1997a), to determine the appropriate plant population density (PPD) of maize that would maximize bean yield in an intercrop system. The treatments were: (a) maize PPD ranging from ...

  9. Past climate-driven range shifts and population genetic diversity in arctic plants

    DEFF Research Database (Denmark)

    Pellissier, Loïc; Eidesen, Pernille Bronken; Ehrich, Dorothee

    2016-01-01

    High intra-specific genetic diversity is necessary for species adaptation to novel environments under climate change, but species tracking suitable conditions are losing alleles through successive founder events during range shift. Here, we investigated the relationship between range shift since ...... the Last Glacial Maximum (LGM) and extant population genetic diversity across multiple plant species to understand variability in species responses...

  10. Transients drive the demographic dynamics of plant populations in variable environments

    DEFF Research Database (Denmark)

    McDonald, Jenni L; Stott, Iain; Townley, Stuart

    2016-01-01

    clear patterns related to growth form. We find a surprising tendency for plant populations to boom rather than bust in response to temporal changes in vital rates and that stochastic growth rates increase with increasing tendency to boom. Synthesis. Transient dynamics contribute significantly...

  11. Forecasting climate change impacts on plant populations over large spatial extents

    Science.gov (United States)

    Tredennick, Andrew T.; Hooten, Mevin B.; Aldridge, Cameron L.; Homer, Collin G.; Kleinhesselink, Andrew R.; Adler, Peter B.

    2016-01-01

    Plant population models are powerful tools for predicting climate change impacts in one location, but are difficult to apply at landscape scales. We overcome this limitation by taking advantage of two recent advances: remotely sensed, species-specific estimates of plant cover and statistical models developed for spatiotemporal dynamics of animal populations. Using computationally efficient model reparameterizations, we fit a spatiotemporal population model to a 28-year time series of sagebrush (Artemisia spp.) percent cover over a 2.5 × 5 km landscape in southwestern Wyoming while formally accounting for spatial autocorrelation. We include interannual variation in precipitation and temperature as covariates in the model to investigate how climate affects the cover of sagebrush. We then use the model to forecast the future abundance of sagebrush at the landscape scale under projected climate change, generating spatially explicit estimates of sagebrush population trajectories that have, until now, been impossible to produce at this scale. Our broadscale and long-term predictions are rooted in small-scale and short-term population dynamics and provide an alternative to predictions offered by species distribution models that do not include population dynamics. Our approach, which combines several existing techniques in a novel way, demonstrates the use of remote sensing data to model population responses to environmental change that play out at spatial scales far greater than the traditional field study plot.

  12. Boom or bust? A comparative analysis of transient population dynamics in plants

    DEFF Research Database (Denmark)

    Stott, Iain; Franco, Miguel; Carslake, David

    2010-01-01

    researchers as further possible effectors of complicated dynamics. Previously published methods of transient analysis have tended to require knowledge of initial population structure. However, this has been overcome by the recent development of the parametric Kreiss bound (which describes how large...... a population must become before reaching its maximum possible transient amplification following a disturbance) and the extension of this and other transient indices to simultaneously describe both amplified and attenuated transient dynamics. We apply the Kreiss bound and other transient indices to a data base...... worrying artefact of basic model parameterization. Synthesis. Transient indices describe how big or how small plant populations can get, en route to long-term stable rates of increase or decline. The patterns we found in the potential for transient dynamics, across many species of plants, suggest...

  13. Assessment of Genetic Heterogeneity in Structured Plant Populations Using Multivariate Whole-Genome Regression Models.

    Science.gov (United States)

    Lehermeier, Christina; Schön, Chris-Carolin; de Los Campos, Gustavo

    2015-09-01

    Plant breeding populations exhibit varying levels of structure and admixture; these features are likely to induce heterogeneity of marker effects across subpopulations. Traditionally, structure has been dealt with as a potential confounder, and various methods exist to "correct" for population stratification. However, these methods induce a mean correction that does not account for heterogeneity of marker effects. The animal breeding literature offers a few recent studies that consider modeling genetic heterogeneity in multibreed data, using multivariate models. However, these methods have received little attention in plant breeding where population structure can have different forms. In this article we address the problem of analyzing data from heterogeneous plant breeding populations, using three approaches: (a) a model that ignores population structure [A-genome-based best linear unbiased prediction (A-GBLUP)], (b) a stratified (i.e., within-group) analysis (W-GBLUP), and (c) a multivariate approach that uses multigroup data and accounts for heterogeneity (MG-GBLUP). The performance of the three models was assessed on three different data sets: a diversity panel of rice (Oryza sativa), a maize (Zea mays L.) half-sib panel, and a wheat (Triticum aestivum L.) data set that originated from plant breeding programs. The estimated genomic correlations between subpopulations varied from null to moderate, depending on the genetic distance between subpopulations and traits. Our assessment of prediction accuracy features cases where ignoring population structure leads to a parsimonious more powerful model as well as others where the multivariate and stratified approaches have higher predictive power. In general, the multivariate approach appeared slightly more robust than either the A- or the W-GBLUP. Copyright © 2015 by the Genetics Society of America.

  14. Plant growth promoting rhizobacteria reduce aphid population and enhance the productivity of bread wheat.

    Science.gov (United States)

    Naeem, Muhammad; Aslam, Zubair; Khaliq, Abdul; Ahmed, Jam Nazir; Nawaz, Ahmad; Hussain, Mubshar

    2018-04-24

    Plant growth promoting rhizobacteria increase plant growth and give protection against insect pests and pathogens. Due to the negative impact of chemical pesticides on environment, alternatives to these chemicals are needed. In this scenario, the biological methods of pest control offer an eco-friendly and an attractive option. In this study, the effect of two plant growth promoting rhizobacterial strains (Bacillus sp. strain 6 and Pseudomonas sp. strain 6K) on aphid population and wheat productivity was evaluated in an aphid susceptible (Pasban-90) and resistant (Inqlab-91) wheat cultivar. The seeds were inoculated with each PGPR strain, separately or the combination of both. The lowest aphid population (2.1tiller -1 ), and highest plant height (85.8cm), number of spikelets per spike (18), grains per spike (44), productive tillers (320m -2 ), straw yield (8.6Mgha -1 ), and grain yield (4.8Mgha -1 ) were achieved when seeds were inoculated with Bacillus sp. strain 6+Pseudomonas sp. strain 6K. The grain yield of both varieties was enhanced by 35.5-38.9% with seed inoculation with both bacterial strains. Thus, the combine use of both PGPR strains viz. Bacillus sp. strain 6+Pseudomonas sp. strain 6K offers an attractive option to reduce aphid population tied with better wheat productivity. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Plant quality and conspecific density effects on Anaphothrips obscurus (Thysanoptera: Thripidae) wing diphenism and population ecology.

    Science.gov (United States)

    Reisig, Dominic D; Godfrey, Larry D; Marcum, Daniel B

    2010-04-01

    Factors that influence thysanopteran wing diphenism are not well known. In these studies, the impact of food quality, mediated through nitrogen addition, and conspecific density was explored on the wing diphenism of an herbivorous thrips species (Anaphothrips obscurus Müller) (Thysanoptera: Thripidae). In the first study, nitrogen was added to timothy grass (Phleum pretense L.) (Poales: Poaceae) transplants, and naturally occurring thrips populations were caged on the plants. Thrips abundance and foliar nutrients were assessed every 2 wk. A separate factorial experiment in growth chambers explored the impact of both plant nitrogen addition and thrips abundance on wing diphenism. Thrips density was manipulated by adding either 3 or 40 thrips to potted and caged timothy. Thrips abundance and foliar nutrients were measured 58 d after treatment placement. Plant quality directly affected thrips wing diphenism independent of thrips density in both experiments. Near the end of the field cage experiment, density may have indirectly impacted wing diphenism. In both experiments, plant quality and thrips density interacted to affect thrips population abundance. Plant quality alone can affect thrips wing diphenism, but it remains unclear whether density alone can affect thrips wing diphenism. This is a unique and understudied system that will be useful to examine generalized theories on the negative interaction between reproduction and dispersal.

  16. Gamma-radiation effect on the parameters of the population recovery of plants

    Directory of Open Access Journals (Sweden)

    N.I. Ivanishvili

    2016-12-01

    Full Text Available Investigation of the effects of different physic-chemical factors on the ecosystems is one of the important scientific tasks. From this perspective, it is to be mentioned an effect of such a strong damaging factor as ionizing radiation. Radiation damage is reflected differently in relation to the levels of organization of living organisms. On the relatively early stage of radiation damage determination of post-irradiation regeneration indicators on population level gives possibility to forecast the sustainability of ecosystems. In order to determine the indicators of post-irradiation regeneration of plant populations we have used as a model water plant – Lemna minor L. During the exposure of radiation on different levels of organization differences are identified not only according to qualitative features but also by the character of direction of the development of the processes of postradiation regeneration. A conclusion is made that if during the acute radiation it is possible to determine radioresistance of certain plants, which is based on the plant potential to post-radiation regeneration, the investigation carried out through chronic irradiation gives the possibility to determine the indicators of the ability of the plant to adapt to the radiation.

  17. Managing Natural and Reintroduced Rare Plant Populations within a Large Government Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Carlsen, T M; Paterson, L E; Alfaro, T M

    2009-07-15

    California is home to many large government reservations that have been in existence for decades. Many of these reservations were formed to support various Department of Defense and Department of Energy national defense activities. Often, only a very small percentage of the reservation is actively used for programmatic activities, resulting in large areas of intact habitat. In some cases, this has benefited rare plant populations, as surrounding lands have been developed for residential or industrial use. However, land management activities such as the suppression or active use of fire and other disturbance (such as fire trail grading) can also work to either the detriment or benefit of rare plant populations at these sites. A management regime that is beneficial to the rare plant populations of interest and is at best consistent with existing site programmatic activities, and at a minimum does not impact such activities, has the best potential for a positive outcome. As a result, some species may be 'difficult' while others may be 'easy' to manage in this context, depending on how closely the species biological requirements match the programmatic activities on the reservation. To illustrate, we compare and contrast two rare annual plant species found at Lawrence Livermore National Laboratory's Site 300. Although several populations of Amsinckia grandiflora have been restored on the site, and all populations are intensively managed, this species continues to decline. In contrast, Blepharizonia plumosa appears to take advantage of the annual controlled burns conducted on the site, and is thriving.

  18. Effects of Plant Extracts on Microbial Population, Methane Emission and Ruminal Fermentation Characteristics in

    Directory of Open Access Journals (Sweden)

    E. T. Kim

    2012-06-01

    Full Text Available This study was conducted to evaluate effects of plant extracts on methanogenesis and rumen microbial diversity in in vitro. Plant extracts (Artemisia princeps var. Orientalis; Wormwood, Allium sativum for. Pekinense; Garlic, Allium cepa; Onion, Zingiber officinale; Ginger, Citrus unshiu; Mandarin orange, Lonicera japonica; Honeysuckle were obtained from the Plant Extract Bank at Korea Research Institute of Bioscience and Biotechnology. The rumen fluid was collected before morning feeding from a fistulated Holstein cow fed timothy and commercial concentrate (TDN; 73.5%, crude protein; 19%, crude fat; 3%, crude fiber; 12%, crude ash; 10%, Ca; 0.8%, P; 1.2% in the ratio of 3 to 2. The 30 ml of mixture, comprising McDougall buffer and rumen liquor in the ratio of 4 to 1, was dispensed anaerobically into serum bottles containing 0.3 g of timothy substrate and plant extracts (1% of total volume, respectively filled with O2-free N2 gas and capped with a rubber stopper. The serum bottles were held in a shaking incubator at 39°C for 24 h. Total gas production in all plant extracts was higher (p<0.05 than that of the control, and total gas production of ginger extract was highest (p<0.05. The methane emission was highest (p<0.05 at control, but lowest (p<0.05 at garlic extract which was reduced to about 20% of methane emission (40.2 vs 32.5 ml/g DM. Other plant extracts also resulted in a decrease in methane emissions (wormwood; 8%, onion; 16%, ginger; 16.7%, mandarin orange; 12%, honeysuckle; 12.2%. Total VFAs concentration and pH were not influenced by the addition of plant extracts. Acetate to propionate ratios from garlic and ginger extracts addition samples were lower (p<0.05, 3.36 and 3.38 vs 3.53 than that of the control. Real-time PCR indicted that the ciliate-associated methanogen population in all added plant extracts decreased more than that of the control, while the fibrolytic bacteria population increased. In particular, the F. succinogens

  19. Population History and Pathways of Spread of the Plant Pathogen Phytophthora plurivora

    Science.gov (United States)

    Schoebel, Corine N.; Stewart, Jane; Gruenwald, Niklaus J.; Rigling, Daniel; Prospero, Simone

    2014-01-01

    Human activity has been shown to considerably affect the spread of dangerous pests and pathogens worldwide. Therefore, strict regulations of international trade exist for particularly harmful pathogenic organisms. Phytophthora plurivora, which is not subject to regulations, is a plant pathogen frequently found on a broad range of host species, both in natural and artificial environments. It is supposed to be native to Europe while resident populations are also present in the US. We characterized a hierarchical sample of isolates from Europe and the US and conducted coalescent-, migration, and population genetic analysis of sequence and microsatellite data, to determine the pathways of spread and the demographic history of this pathogen. We found P. plurivora populations to be moderately diverse but not geographically structured. High levels of gene flow were observed within Europe and unidirectional from Europe to the US. Coalescent analyses revealed a signal of a recent expansion of the global P. plurivora population. Our study shows that P. plurivora has most likely been spread around the world by nursery trade of diseased plant material. In particular, P. plurivora was introduced into the US from Europe. International trade has allowed the pathogen to colonize new environments and/or hosts, resulting in population growth. PMID:24427303

  20. ASSESSMENT OF THE FUKUSIMA NUCLEAR POWER PLANT ACCIDENT CONSEQUENCES BY THE POPULATION IN THE FAR EAST

    Directory of Open Access Journals (Sweden)

    G. V. Arkhangelskaya

    2012-01-01

    Full Text Available The article analyzes the attitude of the population in the five regions of the Far East to the consequences of the accident at the Fukushimai nuclear power plant, as well as the issues of informing about the accident. The analysis of public opinion is based on the data obtained by anonymous questionnaire survey performed in November 2011. In spite of the rather active informing and objective information on the absence of the contamination, most of the population of the Russian Far East believes that radioactive contamination is presented in the areas of their residence, and the main cause of this contamination is the nuclear accident in Japan.

  1. A below-ground herbivore shapes root defensive chemistry in natural plant populations.

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-03-30

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

  2. Influence of small hydropower plants on brown trout (Salmo trutta L. population in Mislinja River

    Directory of Open Access Journals (Sweden)

    Blaž Cokan

    2013-12-01

    Full Text Available The brown trout (Salmo trutta L. in the Mislinja River has been endangered for years because of small hydroelectric power plants. To find out how they are affecting the population of the brown trout in the Mislinja River, we conducted a sampling of the brown trout, using a generating set. We measured the length and weight of all caught specimens and analysed the obtained data. The results are presented in this paper, e.g., biomass, estimations of abundance, average weight, average length and number of captured brown trout. We discovered that the population of the brown trout has decreased in all the sections where water has been taken away for small hydroelectric power plants.

  3. On the optimum energy mix

    International Nuclear Information System (INIS)

    Fujii, Yasumasa

    2011-01-01

    After the Fukushima accident occurred in March 2011, reform of Japan's basic energy plan and energy supply system was reported to be under discussion such as to reduce dependence on nuclear power. Planning of energy policy should be considered based on four evaluation indexes of 'economics'. 'environmental effects', 'stable supply of energy' and 'sustainability'. 'Stable supply of energy' should include stability of domestic energy supply infrastructure against natural disasters in addition to stable supply of overseas resources. 'Sustainability' meant long-term availability of resources. Since there did not exist an almighty energy source and energy supply system superior in terms of every above-mentioned evaluation index, it would be wise to use combining various energy sources and supply system in rational way. This combination lead to optimum energy mix, so-called 'Energy Best Mix'. The author evaluated characteristics of energy sources and energy supply system in terms of four indexes and showed best energy mix from short-, medium- and long-term perspectives. Since fossil fuel resources would deplete anyhow, it would be inevitable for human being to be dependent on non-fossil energy resources regardless of greenhouse effects. At present it would be difficult and no guarantee to establish society fully dependent on renewable energy, then it would be probable to need utilization of nuclear energy in the long term. (T. Tanaka)

  4. Evolution in plant populations as a driver of ecological changes in arthropod communities.

    Science.gov (United States)

    Johnson, Marc T J; Vellend, Mark; Stinchcombe, John R

    2009-06-12

    Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

  5. Evolution in plant populations as a driver of ecological changes in arthropod communities

    Science.gov (United States)

    Johnson, Marc T.J.; Vellend, Mark; Stinchcombe, John R.

    2009-01-01

    Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

  6. Effect of Drought on Herbivore-Induced Plant Gene Expression: Population Comparison for Range Limit Inferences

    Directory of Open Access Journals (Sweden)

    Gunbharpur Singh Gill

    2016-03-01

    Full Text Available Low elevation “trailing edge” range margin populations typically face increases in both abiotic and biotic stressors that may contribute to range limit development. We hypothesize that selection may act on ABA and JA signaling pathways for more stable expression needed for range expansion, but that antagonistic crosstalk prevents their simultaneous co-option. To test this hypothesis, we compared high and low elevation populations of Boechera stricta that have diverged with respect to constitutive levels of glucosinolate defenses and root:shoot ratios; neither population has high levels of both traits. If constraints imposed by antagonistic signaling underlie this divergence, one would predict that high constitutive levels of traits would coincide with lower plasticity. To test this prediction, we compared the genetically diverged populations in a double challenge drought-herbivory growth chamber experiment. Although a glucosinolate defense response to the generalist insect herbivore Spodoptera exigua was attenuated under drought conditions, the plastic defense response did not differ significantly between populations. Similarly, although several potential drought tolerance traits were measured, only stomatal aperture behavior, as measured by carbon isotope ratios, was less plastic as predicted in the high elevation population. However, RNAseq results on a small subset of plants indicated differential expression of relevant genes between populations as predicted. We suggest that the ambiguity in our results stems from a weaker link between the pathways and the functional traits compared to transcripts.

  7. Effects of environmental radiation of Kori nuclear power plant on the human population

    International Nuclear Information System (INIS)

    Kim, Y.J.

    1979-01-01

    In order to clarify and protect the effects of environmental radiation according to the operation of Kori nuclear power plant on human population, the base line survey for the human monitoring, the fauna of land nocturnal insects, and the karyotypes of amphibian species which have been living around the power plant site were carried out. ''Kilchunri'' population which took for the human monitoring lie within a 2km distance from power plant site. Human monitoring, house and food characteristics, individual experience of X-ray exposures, human chromosome analysis and fauna of nocturnal land insects were surveyed and expressed in numerical tables. Chromosome number obtained from the amphibia which were collected around the power plant area was as follows; Kaloula borealis 2N=30, Rana amurensis 2N=26, Rana dybouskii 2N=24, Rana rugosa 2N=26, Rana migromaculata 2N=26, Rana plancyi 2N=26, Bombina orientalis 2N=24, Hyla arborea 2N=24, Bufo stejnegeri 2N=22, and Bufo bufo 2N=22. (author)

  8. Final report on effects of environmental radiation of Kori nuclear power plant on human population

    International Nuclear Information System (INIS)

    Kim, Y.J.; Kim, J.B.; Chung, K.H.; Lee, K.S.; Kim, S.R.; Yang, S.Y.

    1980-01-01

    In order to clarify and protect the effects of environmental radiation according to the operation of Kori nuclear power plant on the human population, the base line survey for the human monitoring, human life habits, expected individual exposure dose, frequencies of chromosomal aberration, gene frequencies and karyotypes in amphibia, fauna, and radiation sensitivities in microorganisms which have been living around the power plant site were carried out. Kilchonri population which took for the human monitoring lie within a 2 km distance from the power plant site. Human monitoring, house and food characteristics, individual experience of x-ray exposures, human chromosome analysis and fauna were surveyed and expressed in numerical tables. Chromosome number obtained from the amphibia which were collected around the power plant area was as follows: Kaloula borealis 2N=30, Rana amurensis 2N=26, Rana dybouskii 2N=24, Rana rugosa 2N=26, Rana nigromaculata 2N=26, Rana plancyi 2N=26, Bombina orientalis 2N=24, Hyla arborea 2N=24, Bufo stejnegeri 2N=22, Bufo bufo 2N=22. (author)

  9. Effects of radiation exposure on plant populations and radiation protection of the environment

    Energy Technology Data Exchange (ETDEWEB)

    Geras' kin, St.A.; Dikarev, V.G.; Oudalova, A.A.; Vasiliev, D.V.; Dikareva, N.S.; Baykova, T.A. [Russian Institute of Agricultural Radiology and Agroecology, Obninsk (Russian Federation); Evseeva, T.I. [Institute of Biology, Komi Scientific Center, Ural Div. RAS, Syktyvkar (Russian Federation)

    2006-07-01

    The results of long-term field experiments in the 30-km Chernobyl NPP zone, In the vicinity of the radioactive wastes storage facility (Leningrad Region), at radium production industry storage cell (the Komi Republic), and in Bryansk Region affected by the ChNPP accident that have been carried out on different species of wild and agricultural plants are discussed. These findings indicate that plant populations growing in areas with relatively low levels of pollution are characterized by the increased level of both cytogenetic disturbances and genetic diversity. The chronic low-dose exposure appears to be an ecological factor creating preconditions for possible changes in the genetic structure of a population. These processes have a genetic basis; therefore, an understanding changes at the genetic level should help in an identifying more complex changes at higher levels. The presented findings add to filling an important gap in our knowledge on remote effects in plant populations and ecosystems from man-made impact. (author)

  10. Effects of radiation exposure on plant populations and radiation protection of the environment

    International Nuclear Information System (INIS)

    Geras'kin, St.A.; Dikarev, V.G.; Oudalova, A.A.; Vasiliev, D.V.; Dikareva, N.S.; Baykova, T.A.; Evseeva, T.I.

    2006-01-01

    The results of long-term field experiments in the 30-km Chernobyl NPP zone, In the vicinity of the radioactive wastes storage facility (Leningrad Region), at radium production industry storage cell (the Komi Republic), and in Bryansk Region affected by the ChNPP accident that have been carried out on different species of wild and agricultural plants are discussed. These findings indicate that plant populations growing in areas with relatively low levels of pollution are characterized by the increased level of both cytogenetic disturbances and genetic diversity. The chronic low-dose exposure appears to be an ecological factor creating preconditions for possible changes in the genetic structure of a population. These processes have a genetic basis; therefore, an understanding changes at the genetic level should help in an identifying more complex changes at higher levels. The presented findings add to filling an important gap in our knowledge on remote effects in plant populations and ecosystems from man-made impact. (author)

  11. WITHIN-POPULATION GENETIC DIVERSITY OF CLIMBING PLANTS AND TREES IN A TEMPERATE FOREST IN CENTRAL CHILE

    OpenAIRE

    Torres-Díaz, Cristian; Ruiz, Eduardo; Salgado-Luarte, Cristian; Molina-Montenegro, Marco A; Gianoli, Ernesto

    2013-01-01

    The climbing habit is a key innovation in angiosperm evolution: climbing plant taxa have greater species richness than their non-climbing sister groups. It is considered that highly diversified clades should show increased among-population genetic differentiation. Less clear is the expected pattern regarding within-population genetic diversity in speciose lineages. We tested the hypothesis of greater within-population genetic diversity in climbing plants compared to trees in a temperate fores...

  12. Impact Of Different Time Planting In Soybeans And Neem Seed Extract Application To Insect Population On Rice Field

    OpenAIRE

    Tamrin Abdullah; Ahdin Gassa; Sri Nur Aminah Ngatimin; Nurariaty Agus And Abdul Fattah

    2015-01-01

    Abstract The purpose of research is to study impact of different time planting of soybean and neem seed extract application to pest insect population on rice field. The research was used Random Block Design in three treatment of insecticides application i.e neem seed extract together with rice planting neem seed extract on soybean 17 days after rice planting synthetic insecticides on 17 days after rice planting Delthametrin on soybean and Chlorpirifos on rice respectively. Research was conduc...

  13. Impact Of Different Time Planting In Soybeans And Neem Seed Extract Application To Insect Population On Rice Field

    OpenAIRE

    Abdullah, Tamrin; Gassa, Ahdin; Ngatimin, Sri Nur Aminah; Agus, Nurariaty; Fattah, Abdul

    2015-01-01

    The purpose of research is to study impact of different time planting of soybean and neem seed extract application to pest insect population on rice field. The research was used Random Block Design in three treatment of insecticides application i.e: neem seed extract together with rice planting, neem seed extract on soybean 17 days after rice planting, synthetic insecticides on 17 days after rice planting (Delthametrin on soybean and Chlorpirifos on rice), respectively. Research was conducted...

  14. Adaptive transgenerational plasticity in plants: case studies, mechanisms, and implications for natural populations

    Directory of Open Access Journals (Sweden)

    Jacob J. Herman

    2011-12-01

    Full Text Available Plants respond to environmental conditions not only by plastic changes to their own development and physiology, but also by altering the phenotypes expressed by their offspring. This transgenerational plasticity was initially considered to entail only negative effects of stressful parental environments, such as production of smaller seeds by resource- or temperature-stressed parent plants, and was therefore viewed as environmental noise. Recent evolutionary ecology studies have shown that in some cases, these inherited environmental effects can include specific growth adjustments that are functionally adaptive to the parental conditions that induced them, which can range from contrasting states of controlled laboratory environments to the complex habitat variation encountered by natural plant populations. Preliminary findings suggest that adaptive transgenerational effects can be transmitted by means of diverse mechanisms including changes to seed provisioning and biochemistry, and epigenetic modifications such as DNA methylation that can persist across multiple generations. These non-genetically inherited adaptations can influence the ecological breadth and evolutionary dynamics of plant taxa and promote the spread of invasive plants. Interdisciplinary studies that join mechanistic and evolutionary ecology approaches will be an important source of future insights.

  15. Adaptive transgenerational plasticity in plants: case studies, mechanisms, and implications for natural populations.

    Science.gov (United States)

    Herman, Jacob J; Sultan, Sonia E

    2011-01-01

    Plants respond to environmental conditions not only by plastic changes to their own development and physiology, but also by altering the phenotypes expressed by their offspring. This transgenerational plasticity was initially considered to entail only negative effects of stressful parental environments, such as production of smaller seeds by resource- or temperature-stressed parent plants, and was therefore viewed as environmental noise. Recent evolutionary ecology studies have shown that in some cases, these inherited environmental effects can include specific growth adjustments that are functionally adaptive to the parental conditions that induced them, which can range from contrasting states of controlled laboratory environments to the complex habitat variation encountered by natural plant populations. Preliminary findings suggest that adaptive transgenerational effects can be transmitted by means of diverse mechanisms including changes to seed provisioning and biochemistry, and epigenetic modifications such as DNA methylation that can persist across multiple generations. These non-genetically inherited adaptations can influence the ecological breadth and evolutionary dynamics of plant taxa and promote the spread of invasive plants. Interdisciplinary studies that join mechanistic and evolutionary ecology approaches will be an important source of future insights.

  16. Using soil seed banks to assess temporal patterns of genetic variation in invasive plant populations.

    Science.gov (United States)

    Fennell, Mark; Gallagher, Tommy; Vintro, Luis Leon; Osborne, Bruce

    2014-05-01

    Most research on the genetics of invasive plant species has focused on analyzing spatial differences among existing populations. Using a long-established Gunnera tinctoria population from Ireland, we evaluated the potential of using plants derived from seeds associated with different soil layers to track genetic variation through time. This species and site were chosen because (1) G. tinctoria produces a large and persistent seed bank; (2) it has been present in this locality, Sraheens, for ∼90 years; (3) the soil is largely undisturbed; and (4) the soil's age can be reliably determined radiometrically at different depths. Amplified fragment length polymorphic markers (AFLPs) were used to assess differences in the genetic structure of 75 individuals sampled from both the standing population and from four soil layers, which spanned 18 cm (estimated at ∼90 years based on (210)Pb and (137)Cs dating). While there are difficulties in interpreting such data, including accounting for the effects of selection, seed loss, and seed migration, a clear pattern of lower total allele counts, percentage polymorphic loci, and genetic diversity was observed in deeper soils. The greatest percentage increase in the measured genetic variables occurred prior to the shift from the lag to the exponential range expansion phases and may be of adaptive significance. These findings highlight that seed banks in areas with long-established invasive populations can contain valuable genetic information relating to invasion processes and as such, should not be overlooked.

  17. Health state of population in vicinity of the Mochovce nuclear power plant. Epidemiologic study

    International Nuclear Information System (INIS)

    Celko, M.; Durov, M.; Letkovicova, M.; Holy, R.; Sedliak, D.; Zrubec, M.; Kristufek, P.; Machata, M.; Prikazsky, V.; Rehak, R.; Stehlikova, B.; Vladar, M.

    1999-01-01

    Results of epidemiologic study of health state of population in vicinity of the Mochovce nuclear power plant (Slovak Republic) are presented. This report is reported under the headings: (1) Introduction; (2) Basic information about Mochovce NPP; (3) Assessment of population exposition by environmental factors; (4) Basic conceptions and principles of epidemiologic study; (5) Demography and health state of population; (6) Characterisation of databases and data; (7) Description of demographic and health indicators; (8) Calculation of demographic and health indicators in vicinity of the Mochovce NPP and in control areas; (9) Calculated indicators; (10) Statistical methods and evaluation of calculated indicators; (11) Summary and conclusions; (12) References; Appendixes: Literature review of similar epidemiologic studies; Quantities and units in radiation protection; Definitions of indicators calculation - specification of method

  18. Evaluation of population density and distribution criteria in nuclear power plant siting

    International Nuclear Information System (INIS)

    Young, M.

    1994-06-01

    The NRC has proposed revisions to 10 CFR 100 which include the codification of nuclear reactor site population density limits to 500 people per square mile, at the siting stage, averaged over any radial distance out to 30 miles, and 1,000 people per square mile within the 40-year lifetime of a nuclear plant. This study examined whether there are less restrictive alternative population density and/or distribution criteria which would provide equivalent or better protection to human health in the unlikely event of a nuclear accident. This study did not attempt to directly address the issue of actual population density limits because there are no US risk standards established for the evaluation of population density limits. Calculations were performed using source terms for both a current generation light water reactor (LWR) and an advanced light water reactor (ALWR) design. The results of this study suggest that measures which address the distribution of the population density, including emergency response conditions, could result in lower average individual risks to the public than the proposed guidelines that require controlling average population density. Studies also indicate that an exclusion zone size, determined by emergency response conditions and reactor design (power level and safety features), would better serve to protect public health than a rigid standard applied to all sites

  19. The influence of geographic location on population exposure to emissions from power plants throughout China

    Energy Technology Data Exchange (ETDEWEB)

    Ying Zhou; Levy, J.I. [Harvard School of Public Health, Boston, MA (United States); Evans, J.S.; Hammitt, J.K. [Harvard Center for Risk Analysis, Boston, MA (United States)

    2006-04-15

    This analysis seeks to evaluate the influence of emission source location on population exposure in China to fine particles and sulfur dioxide. We use the concept of intake fraction, defined as the fraction of material or its precursor released from a source that is eventually inhaled or ingested by a population. We select 29 power-plant sites throughout China and estimate annual average intake fractions at each site, using identical source characteristics to isolate the influence of geographic location. In addition, we develop regression models to interpret the intake fraction values and allow for extrapolation to other sites. To model the concentration increase due to emissions from selected power plants, we used a detailed long-range atmospheric dispersion model, CALPUFF. Primary fine particles have the highest average intake fraction (1 x 10{sup -5}), followed by sulfur dioxide (5 x 10{sup -6}), sulfate from sulfur dioxide (4 x 10{sup -6}), and nitrate from nitrogen oxides (4 x 10{sup -6}). For all pollutants, the intake fractions span approximately an order of magnitude across sites. In the regression analysis, the independent variables are meteorological proxies (such as climate region and precipitation) and population at various distances from the source. We find that population terms can explain a substantial percentage of variability in the intake fraction for all pollutants (R{sup 2} between 0.86 and 0.95 across pollutants), with a significant modifying influence of meteorological regime. Near-source population is more important for primary coarse particles while population at medium to long distance is more important for primary fine particles and secondary particles. A significant portion of intake fraction (especially for secondary particles and primary fine particles) occurs beyond 500 km of the source, emphasizing the need for detailed long-range dispersion modeling. These findings demonstrate that intake fractions for power plants in China can be

  20. The influence of geographic location on population exposure to emissions from power plants throughout China

    International Nuclear Information System (INIS)

    Ying Zhou; Levy, J.I.; Evans, J.S.; Hammitt, J.K.

    2006-01-01

    This analysis seeks to evaluate the influence of emission source location on population exposure in China to fine particles and sulfur dioxide. We use the concept of intake fraction, defined as the fraction of material or its precursor released from a source that is eventually inhaled or ingested by a population. We select 29 power-plant sites throughout China and estimate annual average intake fractions at each site, using identical source characteristics to isolate the influence of geographic location. In addition, we develop regression models to interpret the intake fraction values and allow for extrapolation to other sites. To model the concentration increase due to emissions from selected power plants, we used a detailed long-range atmospheric dispersion model, CALPUFF. Primary fine particles have the highest average intake fraction (1 x 10 -5 ), followed by sulfur dioxide (5 x 10 -6 ), sulfate from sulfur dioxide (4 x 10 -6 ), and nitrate from nitrogen oxides (4 x 10 -6 ). For all pollutants, the intake fractions span approximately an order of magnitude across sites. In the regression analysis, the independent variables are meteorological proxies (such as climate region and precipitation) and population at various distances from the source. We find that population terms can explain a substantial percentage of variability in the intake fraction for all pollutants (R 2 between 0.86 and 0.95 across pollutants), with a significant modifying influence of meteorological regime. Near-source population is more important for primary coarse particles while population at medium to long distance is more important for primary fine particles and secondary particles. A significant portion of intake fraction (especially for secondary particles and primary fine particles) occurs beyond 500 km of the source, emphasizing the need for detailed long-range dispersion modeling. These findings demonstrate that intake fractions for power plants in China can be estimated with

  1. The influence of geographic location on population exposure to emissions from power plants throughout China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Levy, J.I.; Evans, J.S.; Hammitt, J.K. [Harvard University, Boston, MA (United States). School of Public Health

    2006-04-15

    This analysis seeks to evaluate the influence of emission source location on population exposure in China to fine particles and sulfur dioxide. We use the concept of intake fraction, defined as the fraction of material or its precursor released from a source that is eventually inhaled or ingested by a population. We select 29 power-plant sites throughout China and estimate annual average intake fractions at each site, using identical source characteristics to isolate the influence of geographic location. In addition, we develop regression models to interpret the intake fraction values and allow for extrapolation to other sites. To model the concentration increase due to emissions from selected power plants, we used a detailed long-range atmospheric dispersion model, CALPUFF. Primary fine particles have the highest average intake fraction (1 x 10{sup -5}), followed by sulfur dioxide (5 x 10{sup -6}), sulfate from sulfur dioxide (4 x 10{sup -6}), and nitrate from nitrogen oxides (4 x 10{sup -6}). In the regression analysis, the independent variables are meteorological proxies (such as climate region and precipitation) and population at various distances from the source. We find that population terms can explain a substantial percentage of variability in the intake fraction for all pollutants, with a significant modifying influence of meteorological regime. Near-source population is more important for primary coarse particles while population at medium to long distance is more important for primary fine particles and secondary particles. A significant portion of intake fraction (especially for secondary particles and primary fine particles) occurs beyond 500 km of the source, emphasizing the need for detailed long-range dispersion modeling.

  2. Linking Native and Invader Traits Explains Native Spider Population Responses to Plant Invasion.

    Directory of Open Access Journals (Sweden)

    Jennifer N Smith

    Full Text Available Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion. After two years, irregular web-spiders were >30 times more abundant and orb weavers were >23 times more abundant on simulated invasion plots compared to controls. Additionally, irregular web-spiders on simulated invasion plots built webs that were 4.4 times larger and 5.0 times more likely to capture prey, leading to >2-fold increases in recruitment. Orb-weavers showed no differences in web size or prey captures between treatments. Web-spider responses to simulated invasion mimicked patterns following natural invasions, confirming that C. stoebe's architecture is likely the primary attribute driving native spider responses to these invasions. Differences in spider responses were attributable to differences in web construction behaviors relative to historic web substrate constraints. Orb-weavers in this system constructed webs between multiple plants, so they were limited by the overall quantity of native substrates but not by the architecture of individual native plant species. Irregular web-spiders built their webs within individual plants and were greatly constrained by the diminutive architecture of native plant substrates, so they were limited both by quantity and quality of native substrates. Evaluating native species traits in the context of invader-driven change can explain invasion outcomes and help to identify factors limiting native populations.

  3. OPTIMUM RESOURCE ALLOCATION AMONG SELECTED ...

    African Journals Online (AJOL)

    Dr kayce

    the state using the multistage stratified technique for location. ... cocoyam/melon were the crop activities prescribed for an average land owner to maximize gross ... population of 2,833,000 [6] out of which 95% are said to be Christians [4].

  4. The biological model of postradiation restoration of plants on the organismic and population levels of organization

    International Nuclear Information System (INIS)

    Ivanishvili, N.I.; Gogebashvili, M.E.

    2012-01-01

    Full text : When studying postradiating restoration of plants, the question of working out of biological models for testing of biosystems' reliability has become rather urgent. It is known that each organization level of a live organism is characterized by certain mechanisms of postradiating restoration at the formation of various radiobiological reactions. For example, the basic processes at cellular, tissue and organism levels are reparation and regeneration whereas at cenosis level the leading processes are often the forms of population restoration. Besides, in spite of the fact that the population restoration at cenosis level is continuously inked with restoration at the lower organization levels, at this level the specific forms of restoration characterized for only this level are seen. It is natural that studying of the mechanisms of response to the influence of damaging factors needs new methodological approaches on various forms of population restoration with the use of adequate test systems. For this purpose the species of duckweed was used. It was seen that this test-system is characterized by the two levels of response to radiation influence. The first one - at a rather low level of radiation influence (up to 50Gy) when decrease in intensity of leaf growth as well as in colony formation was observed and the second one - at a high level of radiation influence (up to 200Gy) when a crushing of colonies took place and an increase in quantity of undeveloped plant leaves was seen. Thus, thanks to the step character of response of culture duckweed it becomes possible to definite quantity indicators for the investigated populations, not only at the influence of concrete physical and chemical factors but also at multifactorial influences that is often difficult to be calculated. It can be concluded that at the first level of damage an increase of plant resistance to unfavorable factors takes place that is due to the inhibition of growth processes

  5. Estimating population exposure to power plant emissions using CALPUFF: a case study in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Levy, J.I.; Hammitt, J.K.; Evans, J.S. [Harvard University, Boston, MA (USA). School of Public Health, Landmark Center

    2003-02-01

    Power plants are significant emitters of precursor gases of fine particulate matter. To evaluate the public health risk posed by power plants, it is necessary to evaluate population exposure to different pollutants. The concept of intake fraction (the fraction of a pollutant emitted that is eventually inhaled or ingested by a population) has been proposed to provide a simple summary measure of the relationship between emissions and exposure. Currently available intake fraction estimates from developing countries used models that look only at the near field impacts, which may not capture the full impact of a pollution source. This case study demonstrated how the intake fraction of power plant emissions in China can be calculated using a detailed long-range atmospheric dispersion model, CALPUFF. It was found that the intake fraction of primary fine particles is roughly on the order of 10{sup -5}, while the intake fractions of sulfur dioxide, sulfate and nitrate are on the order of 10{sup -6}. These estimates are an order of magnitude higher than the US estimates. The authors also tested how sensitive the results were to key assumptions within the model. The size distribution of primary particles has a large impact on the intake fraction for primary particles while the background ammonia concentration is an important factor influencing the intake fraction of nitrate. The background ozone concentration has a moderate impact on the intake fraction of sulfate and nitrate.

  6. [Energy accumulation and allocation of main plant populations in Aneurolepidium chinense grassland in Songnen Plain].

    Science.gov (United States)

    Qu, Guohui; Wen, Mingzhang; Guo, Jixun

    2003-05-01

    The calorific value of plants is dependent on their biological characteristics and energy-containing materials. The allocation of calorific value in different organs of Aneurolepidium chinese, Calamagrostic epigejos, Puccinellia tenuiflora and Chloris virgata was inflorescence > leaf > stem > dead standing. The seasonal dynamics of standing crop energy of aboveground part of four plant populations showed single-peak curve, and the energy production was Aneurolepidium chinense > Calamagrostic epigejos > Chloris virgata > Puccinellia tenuiflora. Energy increasing rate showed double-peak curve, with the first peak at heading stage and the second peak at maturing stage of seeds. Energy increasing rate was negative at the final stage of growth. The horizontal distribution of energy of aboveground part was that the allocation ratio of different organs at different growth stages was different. There existed a similar trend for vertical distribution of energy among four plant populations, i.e., was the vertical distribution of energy of aboveground part showed a tower shape, with the maximum value in 10-30 cm height. The vertical distribution of energy of underground part showed an inverted tower shape from soil surface to deeper layer, with the maximum value in 0-10 cm depth. The standing crop energy of underground part was about 3-4 times than that of aboveground part.

  7. Low crop plant population densities promote pollen-mediated gene flow in spring wheat (Triticum aestivum L.).

    Science.gov (United States)

    Willenborg, Christian J; Brûlé-Babel, Anita L; Van Acker, Rene C

    2009-12-01

    Transgenic wheat is currently being field tested with the intent of eventual commercialization. The development of wheat genotypes with novel traits has raised concerns regarding the presence of volunteer wheat populations and the role they may play in facilitating transgene movement. Here, we report the results of a field experiment that investigated the potential of spring wheat plant population density and crop height to minimize gene flow from a herbicide-resistant (HR) volunteer population to a non-HR crop. Pollen-mediated gene flow (PMGF) between the HR volunteer wheat population and four conventional spring wheat genotypes varying in height was assessed over a range of plant population densities. Natural hybridization events between the two cultivars were detected by phenotypically scoring plants in F(1) populations followed by verification with Mendelian segregation ratios in the F(1:2) families. PMGF was strongly associated with crop yield components, but showed no association with flowering synchrony. Maximum observed PMGF was always less than 0.6%, regardless of crop height and density. The frequency of PMGF in spring wheat decreased exponentially with increasing plant population density, but showed no dependence on either crop genotype or height. However, increasing plant densities beyond the recommended planting rate of 300 cropped wheat plants m(-2) provided no obvious benefit to reducing PMGF. Nevertheless, our results demonstrate a critical plant density of 175-200 cropped wheat plants m(-2) below which PMGF frequencies rise exponentially with decreasing plant density. These results will be useful in the development of mechanistic models and best management practices that collectively facilitate the coexistence of transgenic and nontransgenic wheat crops.

  8. Population Status of Commercially Important Medicinal Plants in Dehradun Forest Division, Uttarakhand (India

    Directory of Open Access Journals (Sweden)

    Ninad B. RAUT

    2013-05-01

    Full Text Available The objective of forest management in the tropics, in recent decades, has shifted from timber production to biodiversity conservation and maintenance of life support system. However, past forestry practices have greatly influenced the structure of plant communities, preponderance of foreign invasive species, populations of high value medicinal plants as well as other non-wood forest products. We assessed the abundance and distribution of medicinal plants in managed and undisturbed forests of Dehradun Forest Division (DFD, Uttarakhand (India. A total of 80 transects (each 1 km long were laid in various categories of forest types in DFD. This paper deals with distribution, availability and regeneration status of five commercially important species viz., Justicia adhatoda, Aegle marmelos, Phyllanthus emblica, Terminalia bellirica and Terminalia chebula, across different forest types. The study reveals that open canopy forest patches, Lantana infested patches and Acacia catechu-Dalbergia sissoo (Khair -Shisam woodlands in the eastern part of the DFD have excellent potential for the production and sustainable harvest of Justicia adhatoda. Areas those are less suitable for timber production viz., open hill forests, have greater potential for conservation and development of Aegle marmelos, Phyllanthus emblica and Terminalia bellirica. For the production and management of high value medicinal plants in the DFD these ecological considerations need to be kept in mind.

  9. CT4 - Cost-Optimum Procedures

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund; Wittchen, Kim Bjarne

    This report collects the status in European member states regarding implementation of the cos optimum procedure for setting energy performance requirements to new and existing buildings.......This report collects the status in European member states regarding implementation of the cos optimum procedure for setting energy performance requirements to new and existing buildings....

  10. Radiation protection of population under normal operation conditions of nuclear power plants

    International Nuclear Information System (INIS)

    Kunz, Eh.; Shvets, I.

    1976-01-01

    Evolution of shielding is defined in short; approaches suggested for applying in radiation protection or being used are evaluated and classified. Modern views analysis of a risk of biological irradiation consequences in public approaches to health protection in connection with the technical progress side by side with provision of separate persons protection requires attentin to the nuclear power plants protection optimization. Protection optimization suggests the analysis of separate components of technology and protection systems, used materials and constructive solutions, maintenance rules and operating load with respect to environmental discharge of radioactive products. It is expedient to carry out similtaneously the similar analysis with respect to the nuclear power plant personnel irradiation, as separate measures can affect both personnel and population irradiation [ru

  11. Distinguishing plant population and variety with UAV-derived vegetation indices

    Science.gov (United States)

    Oakes, Joseph; Balota, Maria

    2017-05-01

    Variety selection and seeding rate are two important choice that a peanut grower must make. High yielding varieties can increase profit with no additional input costs, while seeding rate often determines input cost a grower will incur from seed costs. The overall purpose of this study was to examine the effect that seeding rate has on different peanut varieties. With the advent of new UAV technology, we now have the possibility to use indices collected with the UAV to measure emergence, seeding rate, growth rate, and perhaps make yield predictions. This information could enable growers to make management decisions early in the season based on low plant populations due to poor emergence, and could be a useful tool for growers to use to estimate plant population and growth rate in order to help achieve desired crop stands. Red-Green-Blue (RGB) and near-infrared (NIR) images were collected from a UAV platform starting two weeks after planting and continued weekly for the next six weeks. Ground NDVI was also collected each time aerial images were collected. Vegetation indices were derived from both the RGB and NIR images. Greener area (GGA- the proportion of green pixels with a hue angle from 80° to 120°) and a* (the average red/green color of the image) were derived from the RGB images while Normalized Differential Vegetative Index (NDVI) was derived from NIR images. Aerial indices were successful in distinguishing seeding rates and determining emergence during the first few weeks after planting, but not later in the season. Meanwhile, these aerial indices are not an adequate predictor of yield in peanut at this point.

  12. Mortality gradients within and among dominant plant populations as barometers of ecosystem change during extreme drought.

    Science.gov (United States)

    Gitlin, Alicyn R; Sthultz, Christopher M; Bowker, Matthew A; Stumpf, Stacy; Paxton, Kristina L; Kennedy, Karla; Muñoz, Axhel; Bailey, Joseph K; Whitham, Thomas G

    2006-10-01

    Understanding patterns of plant population mortality during extreme weather events is important to conservation planners because the frequency of such events is expected to increase, creating the need to integrate climatic uncertainty into management. Dominant plants provide habitat and ecosystem structure, so changes in their distribution can be expected to have cascading effects on entire communities. Observing areas that respond quickly to climate fluctuations provides foresight into future ecological changes and will help prioritize conservation efforts. We investigated patterns of mortality in six dominant plant species during a drought in the southwestern United States. We quantified population mortality for each species across its regional distribution and tested hypotheses to identify ecological stress gradients for each species. Our results revealed three major patterns: (1) dominant species from diverse habitat types (i.e., riparian, chaparral, and low- to high-elevation forests) exhibited significant mortality, indicating that the effects of drought were widespread; (2) average mortality differed among dominant species (one-seed juniper[Juniperus monosperma (Engelm.) Sarg.] 3.3%; manzanita[Arctostaphylos pungens Kunth], 14.6%; quaking aspen[Populus tremuloides Michx.], 15.4%; ponderosa pine[Pinus ponderosa P. & C. Lawson], 15.9%; Fremont cottonwood[Populus fremontii S. Wats.], 20.7%; and pinyon pine[Pinus edulis Engelm.], 41.4%); (3) all dominant species showed localized patterns of very high mortality (24-100%) consistent with water stress gradients. Land managers should plan for climatic uncertainty by promoting tree recruitment in rare habitat types, alleviating unnatural levels of competition on dominant plants, and conserving sites across water stress gradients. High-stress sites, such as those we examined, have conservation value as barometers of change and because they may harbor genotypes that are adapted to climatic extremes.

  13. Estimating population exposure to power plant emissions using CALPUFF: a case study in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Ying Zhou; Levy, J.I. [Harvard School of Public Health, Boston, MA (United States); Hammitt, J.K.; Evans, J.S. [Harvard Center for Risk Analysis, Boston, MA (United States)

    2003-02-01

    Epidemiological studies have shown a significant association between ambient particulate matter (PM) exposures and increased mortality and morbidity risk. Power plants are significant emitters of precursor gases of fine particulate matter. To evaluate the public health risk posed by power plants, it is necessary to evaluate population exposure to different pollutants. The concept of intake fraction (the fraction of a pollutant emitted that is eventually inhaled or ingested by a population) has been proposed to provide a simple summary measure of the relationship between emissions and exposure. Currently available intake fraction estimates from developing countries used models that look only at the near field impacts, which may not capture the full impact of a pollution source. This case study demonstrated how the intake fraction of power plant emissions in China can be calculated using a detailed long-range atmospheric dispersion model-CALPUFF. We found that the intake fraction of primary fine particles is roughly on the order of 10{sup -5}, while the intake fractions of sulfur dioxide, sulfate and nitrate are on the order of 10{sup -6}. These estimates are an order of magnitude higher than the US estimates. We also tested how sensitive the results were to key assumptions within the model. The size distribution of primary particles has a large impact on the intake fraction for primary particles while the background ammonia concentration is an important factor influencing the intake fraction of nitrate. The background ozone concentration has a moderate impact on the intake fraction of sulfate and nitrate. Our analysis shows that this approach is applicable to a developing country and it provides reasonable population exposure estimates. (author)

  14. Geographic population structure in an outcrossing plant invasion after centuries of cultivation and recent founding events.

    Science.gov (United States)

    Gaskin, John F; Schwarzländer, Mark; Gibson, Robert D; Simpson, Heather; Marshall, Diane L; Gerber, Esther; Hinz, Hariet

    2018-04-01

    Population structure and genetic diversity of invasions are the result of evolutionary processes such as natural selection, drift and founding events. Some invasions are also molded by specific human activities such as selection for cultivars and intentional introduction of desired phenotypes, which can lead to low genetic diversity in the resulting invasion. We investigated the population structure, diversity and origins of a species with both accidental and intentional introduction histories, as well as long-term selection as a cultivar. Dyer's woad ( Isatis tinctoria ; Brassicaceae) has been used as a dye source for at least eight centuries in Eurasia, was introduced to eastern USA in the 1600s, and is now considered invasive in the western USA. Our analyses of amplified fragment length polymorphisms (AFLPs) from 645 plants from the USA and Eurasia did not find significantly lower gene diversity ( H j ) in the invaded compared to the native range. This suggests that even though the species was under cultivation for many centuries, human selection of plants may not have had a strong influence on diversity in the invasion. We did find significantly lower genetic differentiation ( F st ) in the invasive range but our results still suggested that there are two distinct invasions in the western USA. Our data suggest that these invasions most likely originated from Switzerland, Ukraine and Germany, which correlates with initial biological control agent survey findings. Genetic information on population structure, diversity and origins assists in efforts to control invasive species, and continued combination of ecological and molecular analyses will help bring us closer to sustainable management of plant invasions.

  15. Mites fluctuation population on peach tree (Prunus persica (L. Batsch and in associated plants

    Directory of Open Access Journals (Sweden)

    Carla Rosana Eichelberger

    2011-09-01

    Full Text Available Despite the importance of peach (Prunus persica (L. Batsch in Rio Grande do Sul, little is known about mites fluctuation population considered important to this crop. The objective of this study was to know the population diversity and fluctuation of mite species associated with Premier and Eldorado varieties in Roca Sales and Venâncio Aires counties, Rio Grande do Sul. The study was conducted from July 2008 to June 2009 when 15 plants were randomly chosen in each area. The plants were divided in quadrants and from each one a branch was chosen from which three leaves were removed: one collected in the apical region, another in the medium and the other in the basal region, totalizing 180 leaves/area. Five of the most abundant associated plants were collected monthly in enough amounts for the screening under the stereoscopic microscope during an hour. A total of 1,124 mites were found belonging to 14 families and 28 species. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836 and Mononychellus planki (McGregor, 1950 were the most abundant phytophagous mites, whereas Typhlodromalus aripo Deleon, 1967 and Phytoseiulus macropilis (Banks, 1904 the most common predatory mites. The period of one hour under stereoscopic microscope was enough to get a representative sample. In both places evaluated the ecologic indices were low, but little higherin Premier (H' 0.56; EqJ: 0.43 when compared to Eldorado (H' 0.53; EqJ 0.40. In Premier constant species were not observed and accessory only Brevipalpus phoenicis (Geijskes, 1939, T. ludeni and T. aripo. Higher abundance was observed in December and January and bigger amount in April. Already in Eldorado, T. ludeni and P. ulmi were constants. Greater abundance was observed in November and December, whereas grater richness in December and January. In both orchards were not found mites in buds. Tetranychus ludeni is the most abundant phytophagous mites with outbreak population in November, December and

  16. Selection and adaptation in irradiated plant and animal populations: a review

    International Nuclear Information System (INIS)

    Hart, D.R.

    1981-03-01

    Available literature on the effects of ionizing radiation on mutation rates, variability and adaptive responses to selection in exposed plant and animal populations is reviewed. Accumulated variability, and hence potential selection differentials, may be increased by many times due to induced mutation. The radiation dose that maximizes induced mutation varies greatly among species, strains and genetic systems. Induced variability tends to enhance the respose to selection, but this effect may be delayed or prevented by an initial reduction in the heritability of induced variation. Significantly, the detrimental effects of harmful mutations in irradiated populations may exceed the beneficial effects of selection for adaptive characteristics. Selection for radioresistance may occur at lethal or sub-lethal radiation doses but dose relationships are highly variable. (author)

  17. Strong Genetic Differentiation of Submerged Plant Populations across Mountain Ranges: Evidence from Potamogeton pectinatus in Iran.

    Science.gov (United States)

    Abbasi, Shabnam; Afsharzadeh, Saeed; Saeidi, Hojjatollah; Triest, Ludwig

    2016-01-01

    Biogeographic barriers for freshwater biota can be effective at various spatial scales. At the largest spatial scale, freshwater organisms can become genetically isolated by their high mountain ranges, vast deserts, and inability to cross oceans. Isolation by distance of aquatic plants is expected to be stronger across than alongside mountain ridges whereas the heterogeneity of habitats among populations and temporary droughts may influence connectivity and hamper dispersal. Suitable aquatic plant habitats became reduced, even for the widespread submerged Potamogeton pectinatus L. (also named Stuckenia pectinata) giving structure to various aquatic habitats. We compared the level of genetic diversity in a heterogeneous series of aquatic habitats across Iran and tested their differentiation over distances and across mountain ranges (Alborz and Zagros) and desert zones (Kavir), with values obtained from temperate region populations. The diversity of aquatic ecosystems across and along large geographic barriers provided a unique ecological situation within Iran. P. pectinatus were considered from thirty-six sites across Iran at direct flight distances ranging from 20 to 1,200 km. Nine microsatellite loci revealed a very high number of alleles over all sites. A PCoA, NJT clustering and STRUCTURE analysis revealed a separate grouping of individuals of southeastern Iranian sites and was confirmed by their different nuclear ITS and cpDNA haplotypes thereby indicating an evolutionary significant unit (ESU). At the level of populations, a positive correlation between allelic differentiation Dest with geographic distance was found. Individual-based STRUCTURE analysis over 36 sites showed 7 genetic clusters. FST and RST values for ten populations reached 0.343 and 0.521, respectively thereby indicating that allele length differences are more important and contain evolutionary information. Overall, higher levels of diversity and a stronger differentiation was revealed among

  18. Geographic structuring and transgenerational maternal effects shape germination in native, but not introduced, populations of a widespread plant invader.

    Science.gov (United States)

    Alba, Christina; Moravcová, Lenka; Pyšek, Petr

    2016-05-01

    Germination is critical in determining species distributions and invasion dynamics. However, is it unclear how often invasive populations evolve germination characteristics different from native populations, because few studies have isolated genetic variation by using seed from garden-grown plants. Additionally, while herbivore-induced transgenerational effects are common, it is unknown whether maternal herbivory differentially shapes germination in native and introduced offspring. We explored germination in native and introduced populations of the North American invader Verbascum thapsus using seed from garden-grown maternal plants, half of which were protected from herbivores. To elucidate (1) germination niche breadth and (2) whether germination conditions affected expression of genetic structuring among populations, we germinated seed under four ecologically relevant temperature regimes. Native populations had a wide germination niche breadth, germinating as well as or better than introduced populations. At cooler temperatures, native populations exhibited a genetically based environmental cline indicative of local adaptation, with populations from warmer locales germinating better than populations from cooler locales. However, this cline was obscured when maternal plants were attacked by herbivores, revealing that local stressors can override the expression of geographic structuring. Introduced populations did not exhibit clinal variation, suggesting its disruption during the introduction process. Native and introduced populations have evolved genetic differences in germination. The result of this difference manifests in a wider germination niche breadth in natives, suggesting that the invasive behavior of V. thapsus in North America is attributable to other factors. © 2016 Botanical Society of America.

  19. Population dose commitments due to radioactive releases from nuclear power plant sites in 1982. Volume 4

    International Nuclear Information System (INIS)

    Baker, D.A.; Peloquin, R.A.

    1986-06-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1982. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 51 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments from both liquid and airborne pathways ranged from a high of 30 person-rem to a low of 0.007 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 130 person-rem for the 100 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 6 x 10 -7 mrem to a high of 0.06 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites

  20. About a dynamic model of interaction of insect population with food plant

    Directory of Open Access Journals (Sweden)

    L.V. Nedorezov

    2011-12-01

    Full Text Available In present paper there is the consideration of mathematical model of food plant (resource - consumer (insect population - pathogen system dynamics which is constructed as a system of ordinary differential equations. The dynamic regimes of model are analyzed and, in particular, with the help of numerical methods it is shown that trigger regimes (regimes with two stable attractors can be realized in model under very simple assumptions about ecological and intra-population processes functioning. Within the framework of model it was assumed that the rate of food flow into the system is constant and functioning of intra-population selfregulative mechanisms can be described by Verhulst model. As it was found, trigger regimes are different with respect to their properties: in particular, in model the trigger regimes with one of stable stationary points on the coordinate plane can be realized (it corresponds to the situation when sick individuals in population are absent and their appearance in small volume leads to their asymptotic elimination; also the regimes with several nonzero stationary states and stable periodic fluctuations were found.

  1. Population dose commitments due to radioactive releases from nuclear power plant sites in 1986

    International Nuclear Information System (INIS)

    Baker, D.A.

    1989-10-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1986. Fifty-year dose commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 66 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 31 person-rem to a low of 0.0007 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 1.7 person-rem. The total population dose for all sites was estimated at 110 person-rem for the 140 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 2 x 10 -6 mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. 12 refs

  2. Population dose commitments due to radioactive releases from nuclear power plant sites in 1984

    International Nuclear Information System (INIS)

    Baker, D.A.

    1988-01-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1984. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 56 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 110 person-rem to a low of 0.002 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 5 person-rem. The total population dose for all sites was estimated at 280 person-rem for the 100 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 6 x 10 -6 mrem to a high of 0.04 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites

  3. Population dose commitments due to radioactive releases from nuclear power plant sites in 1983

    International Nuclear Information System (INIS)

    Baker, D.A.; Peloquin, R.A.

    1987-04-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1983. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 52 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 45 person-rem to a low of 0.002 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 170 person-rem for the 100 million people considered at risk

  4. Population dose commitments due to radioactive releases from nuclear power plant sites in 1985

    International Nuclear Information System (INIS)

    Baker, D.A.

    1988-08-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commericial power reactors operating during 1985. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 61 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 73 person-rem to a low of 0.011 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 200 person-rem for the 110 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 5 /times/ 10/sup /minus/6/ mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites

  5. Drought tolerance in wild plant populations: the case of common beans (Phaseolus vulgaris L..

    Directory of Open Access Journals (Sweden)

    Andrés J Cortés

    Full Text Available Reliable estimations of drought tolerance in wild plant populations have proved to be challenging and more accessible alternatives are desirable. With that in mind, an ecological diversity study was conducted based on the geographical origin of 104 wild common bean accessions to estimate drought tolerance in their natural habitats. Our wild population sample covered a range of mesic to very dry habitats from Mexico to Argentina. Two potential evapotranspiration models that considered the effects of temperature and radiation were coupled with the precipitation regimes of the last fifty years for each collection site based on geographical information system analysis. We found that wild accessions were distributed among different precipitation regimes following a latitudinal gradient and that habitat ecological diversity of the collection sites was associated with natural sub-populations. We also detected a broader geographic distribution of wild beans across ecologies compared to cultivated common beans in a reference collection of 297 cultivars. Habitat drought stress index based on the Thornthwaite potential evapotranspiration model was equivalent to the Hamon estimator. Both ecological drought stress indexes would be useful together with population structure for the genealogical analysis of gene families in common bean, for genome-wide genetic-environmental associations, and for postulating the evolutionary history and diversification processes that have occurred for the species. Finally, we propose that wild common bean should be taken into account to exploit variation for drought tolerance in cultivated common bean which is generally considered susceptible as a crop to drought stress.

  6. Volatile Constituents of Different Plant Parts and Populations of Malabaila aurea Boiss. from Montenegro

    Directory of Open Access Journals (Sweden)

    Ivan Vučković

    2014-03-01

    Full Text Available The volatile constituents of different plant parts and populations of Malabaila aurea Boiss. from Montenegro were obtained by simultaneous distillation-extraction and analyzed by GC-FID and GC-MS. A total of 12 samples were examined and 45 compounds were identified. The volatile content of different M. aurea populations was very similar, while the volatile fractions obtained from different plant parts showed significant qualitative and quantitative differences. The most abundant compounds found in stems & leaves were apiole (51.0-56.3%, myristicin (16.3-25.4%, and falcarinol (4.1-10.7%. The roots showed the same major components, but with different relative abundances: 30.9-49.1% of apiole, 12.9-34.7% of falcarinol, and 9.9-31.1% of myristicin. The volatile constituents of fruits & flowers were remarkably different, containing up to 71.2-80.5% octyl butyrate, 11.4-18.0% octanol, and 2.7-6.8% octyl hexanoate. The results were discussed as possible indication of relatedness of Malabaila aurea and Pastinacasativa (parsnip .

  7. ROLE OF PLANTS FOUND IN NORTH EAST INDIA AND BANGLADESH IN CONTROLLING POPULATION GROWTH

    Directory of Open Access Journals (Sweden)

    Jhimly Das

    2014-08-01

    Full Text Available Being part of the Indian subcontinent both the North Eastern region of India and the Bangladesh share a long common cultural, economic and political history. One of the most critical problems of developing countries like India as well as Bangladesh is their enormous increase in human population. Contraceptive Prevalence Rate (CPR of India is 48.3 and that of Bangladesh is 53.8. As the large majority of population of both the countries belong to rural area, the family planning programmes have largely remained unsuccessful because of many factors including lack of availability of contraceptive drugs in rural markets, lack of accessibility of rural people to medical personnel as well as the lack of acceptability of synthetic drugs due to various socio-cultural and religious perceptions prevailing among many ethnic communities. These contributed to a growing interest among researchers in developing contraceptives of natural origin and at present natural herbal contraception have become one of the major focuses of modern contraceptive research. Since time immemorial herbal drugs are being practiced by various rural communities and ethnic tribes in North East India as well as in Bangladesh, and hence the acceptability of herbal contraceptives is expected to be much higher among rural folk. In different parts of North East India and Bangladesh, ethnic communities are using plant based medicinal products till today. This study aims at highlighting the contraceptive property of some plants found in North-Eastern India as well as in Bangladesh.

  8. Pollutants emitted by a cement plant: health risks for the population living in the neighborhood

    International Nuclear Information System (INIS)

    Schuhmacher, Marta; Domingo, J.L.; Garreta, Josepa

    2004-01-01

    The aim of this study was to investigate the health risks due to combustor emissions in the manufacturing of Portland cement for the population living in the neighborhood of a cement kiln in Catalonia, Spain. Pollutants emitted to the atmosphere in the course of cement production were modeled. The ISC3-ST model was applied to estimate air dispersion of the contaminants emitted by the cement plant. Air concentrations of NO 2 , SO 2 , PM 10 , metals, and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), as well as the potential exposure in the vicinity of the facility, were assessed via models based on US EPA guidance documents. PCDD/F and metal concentrations were also modeled for soil and vegetation. Based on these concentrations, the levels of human exposure were calculated. Individual cancer and noncancer risks for the emissions of the cement kiln were assessed. Health effects due to NO 2 , SO 2 , and PM 10 emissions were also evaluated. Risk assessment was performed as a deterministic analysis. The main individual risk in the population was evaluated in a central-tendency and a high-end approach. The results show that the incremental individual risk due to emissions of the cement plant is very low not only with regard to health effects, but also in relation to toxicological and cancer risks produced by pollutants such as metals and PCDD/Fs emitted by the cement kiln

  9. Selfing for the design of genomic selection experiments in biparental plant populations.

    Science.gov (United States)

    McClosky, Benjamin; LaCombe, Jason; Tanksley, Steven D

    2013-11-01

    Self-fertilization (selfing) is commonly used for population development in plant breeding, and it is well established that selfing increases genetic variance between lines, thus increasing response to phenotypic selection. Furthermore, numerous studies have explored how selfing can be deployed to maximal benefit in the context of traditional plant breeding programs (Cornish in Heredity 65:201-211,1990a, Heredity 65:213-220,1990b; Liu et al. in Theor Appl Genet 109:370-376, 2004; Pooni and Jinks in Heredity 54:255-260, 1985). However, the impact of selfing on response to genomic selection has not been explored. In the current study we examined how selfing impacts the two key aspects of genomic selection-GEBV prediction (training) and selection response. We reach the following conclusions: (1) On average, selfing increases genomic selection gains by more than 70 %. (2) The gains in genomic selection response attributable to selfing hold over a wide range population sizes (100-500), heritabilities (0.2-0.8), and selection intensities (0.01-0.1). However, the benefits of selfing are dramatically reduced as the number of QTLs drops below 20. (3) The major cause of the improved response to genomic selection with selfing is through an increase in the occurrence of superior genotypes and not through improved GEBV predictions. While performance of the training population improves with selfing (especially with low heritability and small population sizes), the magnitude of these improvements is relatively small compared with improvements observed in the selection population. To illustrate the value of these insights, we propose a practical genomic selection scheme that substantially shortens the number of generations required to fully capture the benefits of selfing. Specifically, we provide simulation evidence that indicates the proposed scheme matches or exceeds the selection gains observed in advanced populations (i.e. F 8 and doubled haploid) across a broad range of

  10. Influence of Plant Population and Nitrogen-Fertilizer at Various Levels on Growth and Growth Efficiency of Maize

    Directory of Open Access Journals (Sweden)

    M. I. Tajul

    2013-01-01

    Full Text Available Field experiments were conducted to evaluate plant population and N-fertilizer effects on yield and yield components of maize (Zea mays L.. Three levels of plant populations (53000, 66000, and 800000 plants ha−1 corresponding to spacings of 75 × 25, 60 × 25, and 50 × 25 cm and 4 doses of N (100, 140, 180, and 220 kg ha−1 were the treatment variables. Results revealed that plant growth, light interception (LI, yield attributes, and grain yield varied significantly due to the variations in population density and N-rates. Crop growth rate (CGR was the highest with the population of 80,000 ha−1 receiving 220 kg N ha−1, while relative growth rate (RGR showed an opposite trend of CGR. Light absorption was maximum when most of densely populated plant received the highest amount of N (220 kg N ha−1. Response of soil-plant-analysis development (SPAD value as well as N-content to N-rates was found significant. Plant height was the maximum at the lowest plant density with the highest amount of N. Plants that received 180 kg N ha−1 with 80,000 plants ha−1 had larger foliage, greater SPAD value, and higher amount of grains cob−1 that contributed to the maximum yield (5.03 t ha−1 and the maximum harvest index (HI compared to the plants in other treatments.

  11. Performance of irrigated green corn cultivars in different plant populations at sowing

    Directory of Open Access Journals (Sweden)

    José C. Soares Neto

    Full Text Available ABSTRACT This study aimed to evaluate the yield of green corn hybrids grown under irrigation in different plant populations at sowing. The assay was carried out in the experimental area located in the city of Arapiraca, Alagoas State, Brazil, from November 2015 to January 2016. A randomized complete block design (RCBD was used, in a 2 x 5 factorial scheme with four replicates. A double- and a single-cross hybrid (AG 1051 and BM 3061, which are suitable for green corn production, were cultivated in five spacings between plants at sowing (15.0, 17.5, 20.0, 22.5 and 25.0 cm. The characteristics photosynthetic rate (PR, ear length with rusk (HEL and without husk (UEL, husked ear weight (HEW, unhusked ear weight (UEW, percentage of marketable ears (%ME and weight of husk (HW were evaluated. The double- and single-cross hybrids AG 1051 and BM 3061 showed green ears with commercial standard. The cultivar BM 3061 showed the best results for most of the characteristics related to the performance of green corn (PR, HEL, UEL, UEW, HEW, %ME. The spacing of 17.5 cm between plants at sowing was the most indicated for irrigated green corn cultivation.

  12. The health status of the population neighbouring the nuclear power plants in Slovakia

    International Nuclear Information System (INIS)

    Letkovicova, M.; Letkovicova, H.; Branislav Mihaly, B.; Stehlikova, B.

    2003-01-01

    The objective of this study is to ascertain the actual state of the indicators of health in individual villages within the area under investigation, to ascertain the trend of the development of indicators in the area surrounding the nuclear power plant included in the study, to find whether the occurrence of an indicator is accidental or whether it is determined in the village, make a comparison with another area and with the situation in the Slovak Republic as a whole and, consequently, to determine possible influence of the Power Plant on the indicator's value. It is concluded, that objective and comprehensive evaluation of the health of the population of Slovakia is possible. Enough solid and reliable proofs are available to justify the conclusion that, regardless of the length of the power plants' operation, no unfavourable impacts on human health on their territory have been detected even by the most sophisticated research carried out by a large, multidisciplinary team of researchers from various fields of science

  13. Incidence of plant cover over the autotrophic nitrifying bacteria population in a fragment of Andean forest

    International Nuclear Information System (INIS)

    Gonzalez, Xiomara; Gonzalez, L; Varela, A; Ahumada, J A

    1999-01-01

    It was determined the incidence of plant cover (forest vs. pasture), on the autotrophy nitrifying bacteria, through the effect of biotic factors (radical exudate) and abiotic factors (temperature, ph and humidity), in a high mountain cloud forest fragment. The site of study was located near La Mesa (Cundinamarca) municipality. The temperature of soil was measured in situ, and soil samples were collected and carried to the laboratory for pH and humidity percentage measurements. Serial soil dilution method was used for plating samples on a selective culture medium with ammonium sulphate as nitrogen source, in order to estimate the autotrophic nitrifying bacteria population levels. Grown colonies were examined macro and microscopically. The quantity of nitrates produced by bacteria cultured in vitro was determined spectra-photometrical. In relation to the abiotic factors, there was no significant differences of pH between both plant covers, but there were significant for soil humidity and temperature (p<0.05). There were highly significant differences with respect to the bacteria population levels (p<0.0001) and with respect to nitrate production. This suggests a higher bacterial activity in the under forest cover. The radical exudate from both types of plant cover reduced the viability of bacteria in vitro, from 1:1 to 1:30 exudate bacteria proportions. In the soils physical and chemical analysis, it was found a higher P and Al concentrations, and a higher CIC and organic matter content under the forest cover. It is suggested the importance of this functional group in this ecosystem

  14. Plant Community Richness Mediates Inhibitory Interactions and Resource Competition between Streptomyces and Fusarium Populations in the Rhizosphere.

    Science.gov (United States)

    Essarioui, Adil; LeBlanc, Nicholas; Kistler, Harold C; Kinkel, Linda L

    2017-07-01

    Plant community characteristics impact rhizosphere Streptomyces nutrient competition and antagonistic capacities. However, the effects of Streptomyces on, and their responses to, coexisting microorganisms as a function of plant host or plant species richness have received little attention. In this work, we characterized antagonistic activities and nutrient use among Streptomyces and Fusarium from the rhizosphere of Andropogon gerardii (Ag) and Lespedeza capitata (Lc) plants growing in communities of 1 (monoculture) or 16 (polyculture) plant species. Streptomyces from monoculture were more antagonistic against Fusarium than those from polyculture. In contrast, Fusarium isolates from polyculture had greater inhibitory capacities against Streptomyces than isolates from monoculture. Although Fusarium isolates had on average greater niche widths, the collection of Streptomyces isolates in total used a greater diversity of nutrients for growth. Plant richness, but not plant host, influenced the potential for resource competition between the two taxa. Fusarium isolates had greater niche overlap with Streptomyces in monoculture than polyculture, suggesting greater potential for Fusarium to competitively challenge Streptomyces in monoculture plant communities. In contrast, Streptomyces had greater niche overlap with Fusarium in polyculture than monoculture, suggesting that Fusarium experiences greater resource competition with Streptomyces in polyculture than monoculture. These patterns of competitive and inhibitory phenotypes among Streptomyces and Fusarium populations are consistent with selection for Fusarium-antagonistic Streptomyces populations in the presence of strong Fusarium resource competition in plant monocultures. Similarly, these results suggest selection for Streptomyces-inhibitory Fusarium populations in the presence of strong Streptomyces resource competition in more diverse plant communities. Thus, landscape-scale variation in plant species richness may be

  15. Population Growth Parameters of Tuta absoluta (Lepidoptera: Gelechiidae) on Tomato Plant Using Organic Substrate and Biofertilizers.

    Science.gov (United States)

    Mohamadi, P; Razmjou, J; Naseri, B; Hassanpour, M

    2017-01-01

    The tomato leafminer, Tuta absoluta (Meyrick) is a devastating pest associated with tomato. In this study, effects of tomato plants treated with vermicompost (20, 40, and 60%), humic fertilizer (2, 4 and 6 g/kg soil) and plant growth promoting rhizobacteria (Pseudomonas fluorescens and Bacillus subtilis) were investigated on the life table parameters of T. absoluta in a growth chamber at 25 ± 2 °C, 65 ± 5% RH, and 16:8 (L:D) h. Significant differences were found for the total developmental time, fecundity, and oviposition period of T. absoluta on the treatments tested. The net reproductive rate (R0), intrinsic rate of natural increase (rm), finite rate of increase (λ), mean generation time (T), and doubling time (DT) of T. absoluta were significantly different among treatments tested. We found that in all vermicompost, humic fertilizer and plant growth promoting rhizobacteria treatments, values of R0, rm, and λ were lower than control treatment. However, the lowest values of these parameters were obtained on 2 g/kg humic fertilizer and 40% vermicompost. Furthermore, T. absoluta had longest T and DT values on 2 g/kg humic fertilizer treatment. Data obtained showed that the addition of 2 g/kg humic fertilizer and 40% vermicompost to the growing soil reduced T. absoluta populations in tomato cultures. In addition, these levels of fertilizers improved growth parameters of tomato seedlings (plant height, wet weight, and dry weight) compared with other treatments. These results could be useful in improving the sustainable management of the moth. © The Author 2017. Published by Oxford University Press on behalf of the Entomological Society of America.

  16. NOAA Optimum Interpolation (OI) SST V2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST's plus...

  17. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working...... Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough...... to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters....

  18. NOAA Daily Optimum Interpolation Sea Surface Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (or daily OISST) is an analysis constructed by combining observations from different platforms...

  19. Determination of optimum pressurizer level for kori unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Song, Dong Soo; Lee, Chang Sup; Lee Jae Yong; Kim, Yo Han; Lee, Dong Hyuk [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    To determine the optimum pressurizer water level during normal operation for Kori unit 1, performance and safety analysis are performed. The methodology is developed by evaluating {sup d}ecrease in secondary heat removal{sup e}vents such as Loss of Normal Feedwater accident. To demonstrate optimum pressurizer level setpoint, RETRAN-03 code is used for performance analysis. Analysis results of RETRAN following reactor trip are compared with the actual plant data to justify RETRAN code modelling. The results of performance and safety analyses show that the newly established level setpoints not only improve the performance of pressurizer during transient including reactor trip but also meet the design bases of the pressurizer volume and pressure. 6 refs., 5 figs. (Author)

  20. Determination of optimum pressurizer level for kori unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Song, Dong Soo; Lee, Chang Sup; Yong, Lee Jae; Kim, Yo Han; Lee, Dong Hyuk [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    To determine the optimum pressurizer water level during normal operation for Kori unit 1, performance and safety analysis are performed. The methodology is developed by evaluating {sup d}ecrease in secondary heat removal{sup e}vents such as Loss of Normal Feedwater accident. To demonstrate optimum pressurizer level setpoint, RETRAN-03 code is used for performance analysis. Analysis results of RETRAN following reactor trip are compared with the actual plant data to justify RETRAN code modelling. The results of performance and safety analyses show that the newly established level setpoints not only improve the performance of pressurizer during transient including reactor trip but also meet the design bases of the pressurizer volume and pressure. 6 refs., 5 figs. (Author)

  1. Ways of adaptation of the plant populations to chemical and radioactive contamination

    International Nuclear Information System (INIS)

    Pozolotina, V.; Bezel', V.; Zhuykova, T.; Severu'Khina, O.; Ulyanova, E.

    2004-01-01

    Chemical agents (heavy metals, acids, etc.) and radiation render their influence upon biota being clearly distinct in primary mechanisms of action. However, lively organisms demonstrate one and the same set [arsenal] of response reactions, and thus it is important to reveal the ways of their realization caused by different types of techno-genic impacts. Our work was intended to examine the seed progeny of the dandelion, Taraxacum officinale, from radionuclides-contaminated coeno-populations (grown at the territories influenced by Eastern-Ural radioactive trace, in the Techa-river flood plain) and those situated in the nearest impact zone affected by a large metallurgical plant in the Urals. Plots, differently distanced from the enterprise, showed heavy metal contamination loads 8-33 times higher than the control site did. Radionuclides concentrations ( 90 Sr and 137 Cs) within the contaminated zone exceeded the background values 4-40 times. The study allowed estimation of the seed progeny vitality level for different coeno-populations, comparison of their adaptive potential in regard to heavy metals tolerance and gamma radiation resistance, estimation of abnormal seedlings [sprouts] frequency values. It was shown [found] that under techno-genic pollution the dandelion coeno-populations usually demonstrate wider variations of different characteristics (vitality, mutability, root and leaf growth rates) as compared to those in the background zone. As a general regularity one can regard the phenomenon, that negative effects were not marked to be increased by heavier pollution loads, irrespectively of the agents nature. (author)

  2. Some Genetic Characteristics of the Population Residing Nearby Nuclear Power Plant. The First Step

    International Nuclear Information System (INIS)

    Mkheidze, M.

    2007-01-01

    There is Sosnovy Bor with 60 thousands of inhabitants located 80 km to the west from the centre of St. Petersburg. Here is the greatest and the oldest nuclear power plant, LNPP, with four reactors of the RMBK-1000 (Chernobyl) type. In fact every Sosnovy Bor inhabitant is connected with nuclear technologies. The strategy of the city development is formed and controlled by the policy of federal bodies. It is very difficult to have access to any demographic data and documents reflecting status of population health. Low doses of ionizing radiation are known to cause mutations in germ cells. A great part of the population of Sosnovy Bor works in the NPP and is exposed to low dose ionizing radiation. This paper presents some genetic characteristics of Sosnovy Bor inhabitants including monogenic diseases (phenylketonuria, Duchenne muscular dystrophy, lysosomal diseases, hypothyroidism etc), chromosomal pathology (Down syndrome, Turner and Klinefelter diseases), multiple malformation syndromes and results of aFP screening of pregnant women with high rate of abnormal values of aFP and hHG. These results are obligatory basis and the first step to conduct a study on possible genetic effects of LNPP on genetic structure of Sosnovy Bor population.(author)

  3. Creating new populations of Apium bermejoi (Apiaceae, a critically endangered endemic plant on Menorca (Balearic Islands

    Directory of Open Access Journals (Sweden)

    Rita, Juan

    2013-06-01

    Full Text Available Apium bermejoi is a stoloniferous plant endemic to the island of Menorca (Balearic Islands. It is found only at one locality, and it is listed as Critically Endangered (according to the IUCN criteria. We describe the main results of population restoration actions undertaken under the Recovery Plan for this species, including the following: 1 introduction at two new localities (2008, 2 reinforcement of the original wild and the introduced populations, and 3 a programme for monitoring population dynamics (including both wild and introduced populations spanning four years (2006-2010. The plant material for the introduction and reinforcement projects was generated from seeds gathered in the wild. We carried out a monthly census of all of the individuals/patches and emerged seedlings, from which we assessed their survival at 3-4months. The survival rates of the planted individuals in the two new localities after three months were found to be 59.0% and 56.3%, and more than 80% of the surviving plants produced fruits. A seasonal pattern was observed based on the minimum cover values recorded in the censuses taken at the end of summer, with an increase detected during autumn, and maximal cover values recorded during May/June. The A. bermejoi populations showed large inter-annual fluctuations in both the number of patches and area of occupancy. The number of seedlings varied across the study years, and their survival was linked to specific meteorological events, such as severe storms and dry and hot spells during autumn. The initial phase of introduction for this species has been overall successful, but a final evaluation can only be made on a longterm basis.Apium bermejoi, planta estolonífera endémica de Menorca (Islas Baleares, de la que se conoce una sola localidad en el medio natural, está considerada en Peligro Crítico de extinción (según criterios UICN. Se presentan los principales resultados de las acciones de restauración de las

  4. Computer simulation model for the striped bass young-of-the-year population in the Hudson River. [Effects of entrainment and impingement at power plants on population dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Eraslan, A.H.; Van Winkle, W.; Sharp, R.D.; Christensen, S.W.; Goodyear, C.P.; Rush, R.M.; Fulkerson, W.

    1975-09-01

    This report presents a daily transient (tidal-averaged), longitudinally one-dimensional (cross-section-averaged) computer simulation model for the assessment of the entrainment and impingement impacts of power plant operations on young-of-the-year populations of the striped bass, Morone saxatilis, in the Hudson River.

  5. Population dose commitments due to radioactive releases from nuclear power plant sites in 1988

    International Nuclear Information System (INIS)

    Baker, D.A.

    1992-01-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1988. Fifty-year commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 71 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total collective dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 16 person-rem to a low of 0.0011 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 1.1 person-rem. The total population dose for all sites was estimated at 75 person-rem for the 150 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 3 x 10 -7 mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. However, licensee calculation of doses to the maximally exposed individual at some sites indicated values of up to approximately 100 times average individual doses (on the order of a few millirem per year)

  6. Morpho-physiological and productive biometry in semi-erect cultivars of the cowpea under different plant populations

    Directory of Open Access Journals (Sweden)

    Antônio Aécio de Carvalho Bezerra

    Full Text Available ABSTRACT The aim of this study was to evaluate morpho-physiological and productive characteristics in four semi-erect cultivars of the cowpea under five plant populations. The experiment was conducted in the experimental area of Embrapa Meio-Norte in Teresina in the State of Piauí, Brazil (PI. The experimental design was of randomised complete blocks with four replications, in a 4 x 5 factorial scheme, for evaluating four cultivars (BRS Guariba, BRS Novaera, BRS Potengi and BRS Tumucumaque and five plant populations (105, 2x105, 3x105, 4x105 and 5x105 plants ha-1. There were significant differences between cultivars for primary branch length (PBL, number of lateral branches (NLB, 100-grain weight (HGW, and dry-grain yield (GY. The maximum PBL of 58.5 cm was obtained with 300 thousand plants ha-1, corresponding to an increase of 11.5% when compared to 100 thousand plants ha-1. However, there was a reduction of 91.2% in NLB when compared to the populations of 100 and 500 thousand plants ha-1. The increases of 188% obtained in the leaf area index (LAI in the range of 100 to 500 thousand plants ha-1 explain the linear increase in the crop growth rate (CGR as being due to the greater production of leaf area; also, the decreases seen in the net assimilation rate (NAR, especially in the range of 100 to 300 thousand plants ha-1, are explained as due to the consequent self-shading, which was intensified in the larger populations. LAI, light interception, and CGR in the cultivars increase in response to higher densities. HGW and GY are not significantly affected by the different populations.

  7. Living in isolation - population structure, reproduction, and genetic variation of the endangered plant species Dianthus gratianopolitanus (Cheddar pink).

    Science.gov (United States)

    Putz, Christina M; Schmid, Christoph; Reisch, Christoph

    2015-09-01

    The endangered plant species Dianthus gratianopolitanus exhibits a highly fragmented distribution range comprising many isolated populations. Based upon this pattern of distribution, we selected a study region in Switzerland with a lower magnitude of isolation (Swiss Jura) and another study region in Germany with a higher degree of isolation (Franconian Jura). In each region, we chose ten populations to analyze population structure, reproduction, and genetic variation in a comparative approach. Therefore, we determined population density, cushion size, and cushion density to analyze population structure, investigated reproductive traits, including number of flowers, capsules, and germination rate, and analyzed amplified fragment length polymorphisms to study genetic variation. Population and cushion density were credibly higher in German than in Swiss populations, whereas reproductive traits and genetic variation within populations were similar in both study regions. However, genetic variation among populations and isolation by distance were stronger in Germany than in Switzerland. Generally, cushion size and density as well as flower and capsule production increased with population size and density, whereas genetic variation decreased with population density. In contrast to our assumptions, we observed denser populations and cushions in the region with the higher magnitude of isolation, whereas reproductive traits and genetic variation within populations were comparable in both regions. This corroborates the assumption that stronger isolation must not necessarily result in the loss of fitness and genetic variation. Furthermore, it supports our conclusion that the protection of strongly isolated populations contributes essentially to the conservation of a species' full evolutionary potential.

  8. Impact Of Different Time Planting In Soybeans And Neem Seed Extract Application To Insect Population On Rice Field

    Directory of Open Access Journals (Sweden)

    Tamrin Abdullah

    2015-08-01

    Full Text Available Abstract The purpose of research is to study impact of different time planting of soybean and neem seed extract application to pest insect population on rice field. The research was used Random Block Design in three treatment of insecticides application i.e neem seed extract together with rice planting neem seed extract on soybean 17 days after rice planting synthetic insecticides on 17 days after rice planting Delthametrin on soybean and Chlorpirifos on rice respectively. Research was conducted in rice fields with irrigation channels. The land area is 0.8 hectares with extensive experiments each rice terraces approximately 900 m2 with separate by rice terraces for every treatment. Each treatment consisted of three groups and using nine rice terraces. Samples of the rice plant population is 25 plants per sample unit. The results was showed treatment by neem seed extract with different time planting of soybeans able to reduce number of pest insects populations such as N. virescens 80.38 N. lugens 67.17 S. incertulas 66.5 and L. oratorius 93.46 when compared to treatment with synthetic insecticides Delthamethrin and Chlorpyrifos.

  9. Genetic Population Structure of Cacao Plantings within a Young Production Area in Nicaragua

    Science.gov (United States)

    Trognitz, Bodo; Scheldeman, Xavier; Hansel-Hohl, Karin; Kuant, Aldo; Grebe, Hans; Hermann, Michael

    2011-01-01

    Significant cocoa production in the municipality of Waslala, Nicaragua, began in 1961. Since the 1980s, its economic importance to rural smallholders increased, and the region now contributes more than 50% of national cocoa bean production. This research aimed to assist local farmers to develop production of high-value cocoa based on optimal use of cacao biodiversity. Using microsatellite markers, the allelic composition and genetic structure of cacao was assessed from 44 representative plantings and two unmanaged trees. The population at Waslala consists of only three putative founder genotype spectra (lineages). Two (B and R) were introduced during the past 50 years and occur in >95% of all trees sampled, indicating high rates of outcrossing. Based on intermediate allelic diversity, there was large farm-to-farm multilocus genotypic variation. GIS analysis revealed unequal distribution of the genotype spectra, with R being frequent within a 2 km corridor along roads, and B at more remote sites with lower precipitation. The third lineage, Y, was detected in the two forest trees. For explaining the spatial stratification of the genotype spectra, both human intervention and a combination of management and selection driven by environmental conditions, appear responsible. Genotypes of individual trees were highly diverse across plantings, thus enabling selection for farm-specific qualities. On-farm populations can currently be most clearly recognized by the degree of the contribution of the three genotype spectra. Of two possible strategies for future development of cacao in Waslala, i.e. introducing more unrelated germplasm, or working with existing on-site diversity, the latter seems most appropriate. Superior genotypes could be selected by their specific composite genotype spectra as soon as associations with desired quality traits are established, and clonally multiplied. The two Y trees from the forest share a single multilocus genotype, possibly representing the

  10. The Effect of Temperature and Host Plant Resistance on Population Growth of the Soybean Aphid Biotype 1 (Hemiptera: Aphididae).

    Science.gov (United States)

    Hough, Ashley R; Nechols, James R; McCornack, Brian P; Margolies, David C; Sandercock, Brett K; Yan, Donglin; Murray, Leigh

    2017-02-01

    A laboratory experiment was conducted to evaluate direct and indirect effects of temperature on demographic traits and population growth of biotype 1 of the soybean aphid, Aphis glycines Matsumura. Our objectives were to better understand how temperature influences the expression of host plant resistance, quantify the individual and interactive effects of plant resistance and temperature on soybean aphid population growth, and generate thermal constants for predicting temperature-dependent development on both susceptible and resistant soybeans. To assess indirect (plant-mediated) effects, soybean aphids were reared under a range of temperatures (15-30 °C) on soybean seedlings from a line expressing a Rag1 gene for resistance, and life history traits were quantified and compared to those obtained for soybean aphids on a susceptible soybean line. Direct effects of temperature were obtained by comparing relative differences in the magnitude of life-history traits among temperatures on susceptible soybeans. We predicted that temperature and host plant resistance would have a combined, but asymmetrical, effect on soybean aphid fitness and population growth. Results showed that temperature and plant resistance influenced preimaginal development and survival, progeny produced, and adult longevity. There also appeared to be a complex interaction between temperature and plant resistance for survival and developmental rate. Evidence suggested that the level of plant resistance increased at higher, but not lower, temperature. Soybean aphids required about the same number of degree-days to develop on resistant and susceptible plants. Our results will be useful for making predictions of soybean aphid population growth on resistant plants under different seasonal temperatures. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Plant extracts, metaldehyde and saline solutions on the population control of Bradybaena similaris

    Directory of Open Access Journals (Sweden)

    Junir Antonio Lutinski

    2016-08-01

    Full Text Available ABSTRACT: This study aimed to test the efficiency of plant extracts, metaldehyde and saline solutions, as alternatives to the population control of the snail Bradybaena similaris , and to investigate the effect of the plant extracts in reducing the damage of the snail on Brassica oleracea . The experiments were performed at the Entomology Laboratory of the Universidade Comunitária da Região de Chapecó (Unochapecó, using a random experimental design with nine treatments in triplicate. Five adult individuals of B. similaris were subjected to each trial, totaling 135 snails. The following treatments were tested: cinnamon ( Melia azedarach , timbó ( Ateleia glazioveana , rosemary ( Rosmarinus officinalis , mate herb ( Ilex paraguariensis , two concentrations of metaldehyde (3% and 5%, two concentrations of salt solution (5% and 10 %, and a control treatment (distilled water. To evaluate the survival of B. similaris it was checked the treatments every 24 hours, over four consecutive days. The results revealed that the two concentrations of metaldehyde were fully efficient, that the saline solution (10% had and intermediate efficiency, and that all other treatments were not effective. The treatment with the M. azedarach extract induced a higher consumption of B. oleracea , while the saline solution at 10% and the extracts of R. officinalis and I. paraguariensis inhibited leaf consumption.

  12. Evaluation of genetic diversity in wild populations of Peganum harmala L., a medicinal plant

    Directory of Open Access Journals (Sweden)

    Ranya EL-Bakatoushi

    2018-06-01

    Full Text Available Peganum harmala L. is a perennial herbaceous plant and can be a future drug due to its wide medicinal purposes. Despite its economic importance, the molecular genetics of P. harmal have not yet been studied in detail. Genetic diversity of 12 P. harmala genotypes were investigated by using Inter-Simple Sequence Repeats (ISSR, PCR-RFLP of rDNA-ITS, PCR-SSCP of rDNA-ITS and Simple Sequence Repeat (SSR markers. The level of polymorphism revealed by ITS-SSCP is the lowest, followed by ITS-RFLP then ISSR and the highest polymorphism level was reported for SSR marker. The AMOVA analysis implied that most of the variation occurred within the Populations. A value of inbreeding coefficient Fis estimated by the three co-dominant markers was nearly equal and offer an indication of the partial out-crossing reproductive system of P. harmala. Principal Coordinate Analysis (PCOA plot revealed a clear pattern of clustering based on the locations of collected plants which coincide with the isolation by distance. The study revealed that ITS-SSCP and ISSR markers respectively were more informative than the other used markers in the assessment of genetic diversity of P. harmala. The results reflect the great diversity of P. harmala and data obtained from this study can be used for future collecting missions. Keywords: Peganum harmala, Genetic diversity, ISSR, rDNA-ITS, SSR

  13. Effect of Component Population on the Growth and Yield of Maize ...

    African Journals Online (AJOL)

    Field experiment to determine the optimum component populations of maize (Zea mays L.) and egusi melon Colocynthis citrullus L. Schrad) component crops in intercrop were conducted in 2004 and 2005 cropping seasons. There were three maize populations (17,780; 26,670 and 53,330 plants/ha), three egusi melon ...

  14. Effect of plant and row spacing on the yield and oil contents of castor ...

    African Journals Online (AJOL)

    Castor (Ricinus communis L.) is an industrial non edible oilseed adapted to drier areas. An experiment was conducted in the Central Rift Valley of Ethiopia to determine optimum plant population of castor variety Hiruy. Four plant (50, 60, 70 and 80 cm) and four row spacing (60,80,100 and 120 cm) were arranged in factorial ...

  15. Optimum burnup of BAEC TRIGA research reactor

    International Nuclear Information System (INIS)

    Lyric, Zoairia Idris; Mahmood, Mohammad Sayem; Motalab, Mohammad Abdul; Khan, Jahirul Haque

    2013-01-01

    Highlights: ► Optimum loading scheme for BAEC TRIGA core is out-to-in loading with 10 fuels/cycle starting with 5 for the first reload. ► The discharge burnup ranges from 17% to 24% of U235 per fuel element for full power (3 MW) operation. ► Optimum extension of operating core life is 100 MWD per reload cycle. - Abstract: The TRIGA Mark II research reactor of BAEC (Bangladesh Atomic Energy Commission) has been operating since 1986 without any reshuffling or reloading yet. Optimum fuel burnup strategy has been investigated for the present BAEC TRIGA core, where three out-to-in loading schemes have been inspected in terms of core life extension, burnup economy and safety. In considering different schemes of fuel loading, optimization has been searched by only varying the number of fuels discharged and loaded. A cost function has been defined and evaluated based on the calculated core life and fuel load and discharge. The optimum loading scheme has been identified for the TRIGA core, the outside-to-inside fuel loading with ten fuels for each cycle starting with five fuels for the first reload. The discharge burnup has been found ranging from 17% to 24% of U235 per fuel element and optimum extension of core operating life is 100 MWD for each loading cycle. This study will contribute to the in-core fuel management of TRIGA reactor

  16. Seasonal timing of first rain storms affects rare plant population dynamics

    Science.gov (United States)

    Levine, J.M.; McEachern, A.K.; Cowan, C.

    2011-01-01

    A major challenge in forecasting the ecological consequences of climate change is understanding the relative importance of changes to mean conditions vs. changes to discrete climatic events, such as storms, frosts, or droughts. Here we show that the first major storm of the growing season strongly influences the population dynamics of three rare and endangered annual plant species in a coastal California (USA) ecosystem. In a field experiment we used moisture barriers and water addition to manipulate the timing and temperature associated with first major rains of the season. The three focal species showed two- to fivefold variation in per capita population growth rates between the different storm treatments, comparable to variation found in a prior experiment imposing eightfold differences in season-long precipitation. Variation in germination was a major demographic driver of how two of three species responded to the first rains. For one of these species, the timing of the storm was the most critical determinant of its germination, while the other showed enhanced germination with colder storm temperatures. The role of temperature was further supported by laboratory trials showing enhanced germination in cooler treatments. Our work suggests that, because of species-specific cues for demographic transitions such as germination, changes to discrete climate events may be as, if not more, important than changes to season-long variables.

  17. A theoretical analysis of population genetics of plants on restored habitats

    Energy Technology Data Exchange (ETDEWEB)

    Bogoliubov, A.G. [Botanical Institute, Russian Academy of Science, St. Petersburg (Russian Federation); Loehle, C. [Argonne National Lab., IL (United States)

    1995-02-01

    Seed and propagules used for habitat restoration are not likely to be closely adapted to local site conditions. Rapid changes of genotypes frequencies on local microsites and/or microevolution would allow plants to become better adapted to a site. These same factors would help to maintain genetic diversity and ensure the survival of small endangered populations. We used population genetics models to examine the selection of genotypes during establishment on restored sites. Vegetative spread was shown to affect selection and significantly reduce genetic diversity. To study general microevolution, we linked a model of resource usage with a genetics model and analyzed competition between genotypes. A complex suite of feasible ecogenetic states was shown to result. The state actually resulting would depend strongly on initial conditions. This analysis indicated that genetic structure can vary locally and can produce overall genetic variability that is not simply the result of microsite adaptations. For restoration activities, the implication is that small differences in seed source could lead to large differences in local genetic structure after selection.

  18. A theoretical analysis of population genetics of plants on restored habitats

    Energy Technology Data Exchange (ETDEWEB)

    Bogoliubov, A.G. [Russian Academy of Science, St. Petersburg (Russian Federation). Botanical Inst.; Loehle, C. [Argonne National Lab., IL (United States). Environmental Research Div.

    1997-07-01

    Seed and propagules used for habitat restoration are not likely to be closely adapted to local site conditions. Rapid changes of genotypes frequencies on local microsites and/or microevolution would allow plants to become better adapted to a site. These same factors would help to maintain genetic diversity and ensure the survival of small endangered populations. The authors used population genetics models to examine the selection of genotypes during establishment on restored sites. Vegetative spread was shown to affect selection and significantly reduce genetic diversity. To study general microevolution, the authors linked a model of resource usage with a genetics model and analyzed competition between genotypes. A complex suite of feasible ecogenetic states was shown to result. The state actually resulting would depend strongly on initial conditions. This analysis indicated that genetic structure can vary locally and can produce overall genetic variability that is not simply the result of microsite adaptations. For restoration activities, the implication is that small differences in seed source could lead to large differences in local genetic structure after selection.

  19. Phylogeny, plant species, and plant diversity influence carbon use phenotypes among Fusarium populations in the rhizosphere microbiome

    Science.gov (United States)

    Carbon use by microorganisms in the rhizosphere microbiome has been linked to plant pathogen suppression and increased mineralization of soil nutrients for plant uptake, however factors that influence carbon use traits are poorly understood for most microbial groups. This work characterized the rela...

  20. Adaptive Potential for the Invasion of Novel Host Plants in the Bean Weevil: Patterns of the Reproductive Behavior in Populations That Used Different Host Plants

    Directory of Open Access Journals (Sweden)

    Dragana Milanović

    2007-01-01

    Full Text Available The goal of this work was to examine interpopulation patterns in the reproductive behavior of populations of bean weevil (Acanthoscelides obtectus Say; Coleoptera: Bruchidae that had different levels of specialization on their native host plant – the bean (Phaseolus vulgaris L., as well as on a novel host plant – the chickpea (Cicer arietinum Thorn. The obtained pattern of interpopulation mating behavior seemed exactly as if the males on chickpea had evolved a specific odor and/or a courtship ritual that females of populationson bean found repulsive. Unlike females, the males of bean populations seemed to be willing to mate with females from the population on chickpea equally as with their own females. Such an asymmetric pattern of reproductive isolation between populations ofa species has been often considered an initial phase of a process of speciation. Thus, our results could be a good starting point for further, thorough examination of both the role of the level of host specialization in females and the role of biochemical characteristics of male pheromone (and/or their cuticular hydrocarbones in the evolution of pre-reproductive isolation between insect populations.As the results of this study, together those of previous studies on A. obtectus, suggest great evolutionary potential for invasions of and fast specialization on novel host plants, they could provide valuable information for the development of long-term strategiesunder the programmes of Integrated Pest Management.

  1. Influence of intercrops on pests' populations in upland rice (Oriza ...

    African Journals Online (AJOL)

    User

    of calorie for many Africans. Efforts have been made ... white and no grain filling occurs, thus producing white heads (IRRI ... crop's environment viz-a-viz resurgence of target pests .... The data obtained were subjected to Analysis of Variance (ANOVA) according to .... as optimum plant population of the component crops. In.

  2. Modified loss coefficients in the determination of optimum generation scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, D.; Bordoloi, P.K. (Assam Engineering Coll. (IN))

    1991-03-01

    A modified method has been evolved to form the loss coefficients of an electrical power system network by decoupling load and generation and thereby creating additional fictitious load buses. The system losses are then calculated and co-ordinated to arrive at an optimum scheduling of generation using the standard co-ordination equation. The method presented is superior to the ones currently available, in that it is applicable to a multimachine system with random variation of load and it accounts for limits in plant generations and line losses. The precise nature of results and the economy in the cost of energy production obtained by this method is quantified and presented. (author).

  3. Vector population growth and condition-dependent movement drive the spread of plant pathogens.

    Science.gov (United States)

    Shaw, Allison K; Peace, Angela; Power, Alison G; Bosque-Pérez, Nilsa A

    2017-08-01

    Plant viruses, often spread by arthropod vectors, impact natural and agricultural ecosystems worldwide. Intuitively, the movement behavior and life history of vectors influence pathogen spread, but the relative contribution of each factor has not been examined. Recent research has highlighted the influence of host infection status on vector behavior and life history. Here, we developed a model to explore how vector traits influence the spread of vector-borne plant viruses. We allowed vector life history (growth rate, carrying capacity) and movement behavior (departure and settlement rates) parameters to be conditional on whether the plant host is infected or healthy and whether the vector is viruliferous (carrying the virus) or not. We ran simulations under a wide range of parameter combinations and quantified the fraction of hosts infected over time. We also ran case studies of the model for Barley yellow dwarf virus, a persistently transmitted virus, and for Potato virus Y, a non-persistently transmitted virus. We quantified the relative importance of each parameter on pathogen spread using Latin hypercube sampling with the statistical partial rank correlation coefficient technique. We found two general types of mechanisms in our model that increased the rate of pathogen spread. First, increasing factors such as vector intrinsic growth rate, carrying capacity, and departure rate from hosts (independent of whether these factors were condition-dependent) led to more vectors moving between hosts, which increased pathogen spread. Second, changing condition-dependent factors such as a vector's preference for settling on a host with a different infection status than itself, and vector tendency to leave a host of the same infection status, led to increased contact between hosts and vectors with different infection statuses, which also increased pathogen spread. Overall, our findings suggest that vector population growth rates had the greatest influence on rates of virus

  4. Optimum Tilt Angle at Tropical Region

    Directory of Open Access Journals (Sweden)

    S Soulayman

    2015-02-01

    Full Text Available : One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector Equator facing position is the best, is valid for tropical region? Thus, it is required to determine the optimum tilt as for Equator facing and for Pole oriented collectors. In addition, the question that may arise: how many times is reasonable for adjusting collector tilt angle for a definite value of surface azimuth angle? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle for the solar collector at any latitude. This model was applied for determining optimum tilt angle and orientation in the tropical zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 11% to 18% more than the case of a solar collector fixed on a horizontal surface.

  5. Ecological context of the evolution of self-pollination in Clarkia xantiana: population size, plant communities, and reproductive assurance.

    Science.gov (United States)

    Moeller, David A; Geber, Monica A

    2005-04-01

    The repeated evolutionary transition from outcrossing to self-pollination in flowering plants has been suggested to occur because selfing provides reproductive assurance. Reports from biogeographical and ecological surveys indicate that selfing taxa are often associated with stressful and ephemeral environments, situations in which plant abundance is low (e.g., Baker's law) and with novel plant communities, however experimental tests of ecological hypotheses are few. In this study, we examined the ecological context of selection on mating system traits (herkogamy and protandry) in a California annual, Clarkia xantiana, where natural selfing populations differ from outcrossing populations in that they are often of small size or low density and occur mainly outside the range of pollinator-sharing congeners. We constructed artificial populations of plants with broad genetic variation in floral traits and manipulated two ecological factors, plant population size, and the presence versus absence of pollinator-sharing congeners, in the center of the geographic range of outcrossing populations. We found evidence for context-dependent selection on herkogamy and protandry via female fitness in which reduced traits, which promote autonomous selfing, were favored in small populations isolated from congeners whereas selection was comparatively weak in large populations or when congeners were present. In small, isolated populations, the fertility of plants with low herkogamy or protandry was elevated by 66% and 58%, respectively, compared to those with high herkogamy or protandry. The presence of pollinator-sharing congeners augmented bee visitation rates to C. xantiana flowers by 47% for all bees and by 93% for pollen specialists. By facilitating pollinator visitation, congeners mitigated selection on mating system traits in small populations, where outcross mating success is often low (the Allee effect). We also found support for the hypothesis that pollinator availability

  6. [Using IRAP markers for analysis of genetic variability in populations of resource and rare species of plants].

    Science.gov (United States)

    Boronnikova, S V; Kalendar', R N

    2010-01-01

    Species-specific LTR retrotransposons were first cloned in five rare relic species of drug plants located in the Perm' region. Sequences of LTR retrotransposons were used for PCR analysis based on amplification of repeated sequences from LTR or other sites of retrotransposons (IRAP). Genetic diversity was studied in six populations of rare relic species of plants Adonis vernalis L. by means of the IRAP method; 125 polymorphic IRAP-markers were analyzed. Parameters for DNA polymorphism and genetic diversity of A. vernalis populations were determined.

  7. A field experiment demonstrating plant life-history evolution and its eco-evolutionary feedback to seed predator populations.

    Science.gov (United States)

    Agrawal, Anurag A; Johnson, Marc T J; Hastings, Amy P; Maron, John L

    2013-05-01

    The extent to which evolutionary change occurs in a predictable manner under field conditions and how evolutionary changes feed back to influence ecological dynamics are fundamental, yet unresolved, questions. To address these issues, we established eight replicate populations of native common evening primrose (Oenothera biennis). Each population was planted with 18 genotypes in identical frequency. By tracking genotype frequencies with microsatellite DNA markers over the subsequent three years (up to three generations, ≈5,000 genotyped plants), we show rapid and consistent evolution of two heritable plant life-history traits (shorter life span and later flowering time). This rapid evolution was only partially the result of differential seed production; genotypic variation in seed germination also contributed to the observed evolutionary response. Since evening primrose genotypes exhibited heritable variation for resistance to insect herbivores, which was related to flowering time, we predicted that evolutionary changes in genotype frequencies would feed back to influence populations of a seed predator moth that specializes on O. biennis. By the conclusion of the experiment, variation in the genotypic composition among our eight replicate field populations was highly predictive of moth abundance. These results demonstrate how rapid evolution in field populations of a native plant can influence ecological interactions.

  8. Plant population and habitat characteristics of the endemic Sonoran Desert cactus Peniocereus striatus in Organ Pipe Cactus National Monument, Arizona

    Science.gov (United States)

    Anderson, Greta; Rutman, Sue; Munson, Seth M.

    2010-01-01

    Peniocereus striatus (Brandegee) Buxb. (Cactaceae) is an endemic Sonoran Desert cactus that reaches its northern range limit in southwestern Arizona. One U.S. population occupies a small area of Organ Pipe Cactus National Monument near the U.S./Mexico international boundary, which has been monitored since 1939. An extensive survey conducted in 2002, covering 177 ha, resulted in the discovery of 88 new plants, in addition to the relocation of 57 plants found in previous surveys. Despite potential increases in population size and spatial distribution, mean plant height and number of basal stems has not significantly changed in recent years. Bud scars revealed that a majority of the population was sexually mature. Peniocereus striatus occurrence increased with decreasing slope, spanned every slope aspect, and was highest on rocky soils, but was noticeably low on west and northwest slopes and areas where severe land degradation had previously occurred. Over half of P. striatus plants were nursed by shrubs and subshrubs, while 40% occurred under leguminous trees. A severe frost in January 2002 top-killed 19% of the population, with the greatest damage in drainage bottoms. However, long-term (1944–2002) climate records show that there has been an overall increase in the number of frost free days in the region, which, coupled with land use change, has implications for the future health of this population.

  9. Role of population genetics in guiding ecological responses to climate.

    Science.gov (United States)

    Rehfeldt, Gerald E; Leites, Laura P; Joyce, Dennis G; Weiskittel, Aaron R

    2018-02-01

    Population responses to climate were assessed using 3-7 years height growth data gathered for 266 populations growing in 12 common gardens established in the 1980s as part of five disparate studies of Pinus contorta var. latifolia. Responses are interpreted according to three concepts: the ecological optimum, the climate where a population is competitively exclusive and in which, therefore, it occurs naturally; the physiological optimum, the climate where a population grows best but is most often competitively excluded; and growth potential, the innate capacity for growth at the physiological optimum. Statistical analyses identified winter cold, measured by the square root of negative degree-days calculated from the daily minimum temperature (MINDD0 1/2 ), as the climatic effect most closely related to population growth potential; the colder the winter inhabited by a population, the lower its growth potential, a relationship presumably molded by natural selection. By splitting the data into groups based on population MINDD0 1/2 and using a function suited to skewed normal distributions, regressions were developed for predicting growth from the distance in climate space (MINDD0 1/2 ) populations had been transferred from their native location to a planting site. The regressions were skewed, showing that the ecological optimum of most populations is colder than the physiological optimum and that the discrepancy between the two increases as the ecological optimum becomes colder. Response to climate change is dependent on innate growth potential and the discrepancy between the two optima and, therefore, is population-specific, developing out of genotype-environment interactions. Response to warming in the short-term can be either positive or negative, but long term responses will be negative for all populations, with the timing of the demise dependent on the amount of skew. The results pertain to physiological modeling, species distribution models, and climate

  10. Population growth and within-plant distribution of the striped mealybug Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae on cotton

    Directory of Open Access Journals (Sweden)

    Martin D. Oliveira

    2014-03-01

    Full Text Available Population growth and within-plant distribution of the striped mealybug Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae on cotton. The striped mealybug, Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae, is a widely distributed and polyphagous pest species, which naturally occurs on cotton plants in Brazil. This study evaluated the establishment and population growth as well as the within-plant distribution of F. virgata on four cotton cultivars: CNPA 7H (white fibers, BRS Verde, BRS Safira, and BRS Rubi (colored fibers. The experiment was conducted in a complete randomized design with four treatments (cultivars and 18 replications of each. Thus, cotton plants of each cultivar were infested with 100 newly hatched nymphs of F. virgata. The number of adult female mealybugs and the total number of mealybugs per plant were quantified, respectively, at 25 and 50 days after infestation. The developmental and pre-reproductive periods were also determined. Furthermore, we verified the distribution of F. virgata on the plant parts at 25 and 50 days after infestation. Ferrisia virgata showed similar growth of 412-fold in the four cotton cultivars studied. Also, the nymphs were spread on infested leaves; the secondgeneration nymphs were spread and established in all plant parts. Our results characterize F. virgata as having much potential as an important cotton pest in Brazil.

  11. Common Core: Teaching Optimum Topic Exploration (TOTE)

    Science.gov (United States)

    Karge, Belinda Dunnick; Moore, Roxane Kushner

    2015-01-01

    The Common Core has become a household term and yet many educators do not understand what it means. This article explains the historical perspectives of the Common Core and gives guidance to teachers in application of Teaching Optimum Topic Exploration (TOTE) necessary for full implementation of the Common Core State Standards. An effective…

  12. Optimum fiber distribution in singlewall corrugated fiberboard

    Science.gov (United States)

    Millard W. Johnson; Thomas J. Urbanik; William E. Denniston

    1979-01-01

    Determining optimum distribution of fiber through rational design of corrugated fiberboard could result in significant reductions in fiber required to meet end-use conditions, with subsequent reductions in price pressure and extension of the softwood timber supply. A theory of thin plates under large deformations is developed that is both kinematically and physically...

  13. Calculations enable optimum design of magnetic brake

    Science.gov (United States)

    Kosmahl, H. G.

    1966-01-01

    Mathematical analysis and computations determine optimum magnetic coil configurations for a magnetic brake which controllably decelerates a free falling load to a soft stop. Calculations on unconventionally wound coils determine the required parameters for the desired deceleration with minimum electrical energy supplied to the stationary coil.

  14. Genotype x environment interaction and optimum resource ...

    African Journals Online (AJOL)

    ... x E) interaction and to determine the optimum resource allocation for cassava yield trials. The effects of environment, genotype and G x E interaction were highly significant for all yield traits. Variations due to G x E interaction were greater than those due to genotypic differences for all yield traits. Genotype x location x year ...

  15. Determination of the Optimum Thickness of Approximately ...

    African Journals Online (AJOL)

    In an attempt to conserve the world's scarce energy and material resources, a balance between the cost of heating a material and the optimum thickness of the material becomes vey essential. One of such materials is the local cast aluminium pot commonly used as cooking ware in Nigeria. This paper therefore sets up a ...

  16. Development of the optimum rotor theories

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær; van Kuik, Gijs A.M.

    The purpose of this study is the examination of optimum rotor theories with ideal load distributions along the blades, to analyze some of the underlying ideas and concepts, as well as to illuminate them. The book gives the historical background of the issue and presents the analysis of the problems...

  17. The leaf angle distribution of natural plant populations: assessing the canopy with a novel software tool.

    Science.gov (United States)

    Müller-Linow, Mark; Pinto-Espinosa, Francisco; Scharr, Hanno; Rascher, Uwe

    2015-01-01

    Three-dimensional canopies form complex architectures with temporally and spatially changing leaf orientations. Variations in canopy structure are linked to canopy function and they occur within the scope of genetic variability as well as a reaction to environmental factors like light, water and nutrient supply, and stress. An important key measure to characterize these structural properties is the leaf angle distribution, which in turn requires knowledge on the 3-dimensional single leaf surface. Despite a large number of 3-d sensors and methods only a few systems are applicable for fast and routine measurements in plants and natural canopies. A suitable approach is stereo imaging, which combines depth and color information that allows for easy segmentation of green leaf material and the extraction of plant traits, such as leaf angle distribution. We developed a software package, which provides tools for the quantification of leaf surface properties within natural canopies via 3-d reconstruction from stereo images. Our approach includes a semi-automatic selection process of single leaves and different modes of surface characterization via polygon smoothing or surface model fitting. Based on the resulting surface meshes leaf angle statistics are computed on the whole-leaf level or from local derivations. We include a case study to demonstrate the functionality of our software. 48 images of small sugar beet populations (4 varieties) have been analyzed on the base of their leaf angle distribution in order to investigate seasonal, genotypic and fertilization effects on leaf angle distributions. We could show that leaf angle distributions change during the course of the season with all varieties having a comparable development. Additionally, different varieties had different leaf angle orientation that could be separated in principle component analysis. In contrast nitrogen treatment had no effect on leaf angles. We show that a stereo imaging setup together with the

  18. Genet-specific DNA methylation probabilities detected in a spatial epigenetic analysis of a clonal plant population.

    Directory of Open Access Journals (Sweden)

    Kiwako S Araki

    Full Text Available In sessile organisms such as plants, spatial genetic structures of populations show long-lasting patterns. These structures have been analyzed across diverse taxa to understand the processes that determine the genetic makeup of organismal populations. For many sessile organisms that mainly propagate via clonal spread, epigenetic status can vary between clonal individuals in the absence of genetic changes. However, fewer previous studies have explored the epigenetic properties in comparison to the genetic properties of natural plant populations. Here, we report the simultaneous evaluation of the spatial structure of genetic and epigenetic variation in a natural population of the clonal plant Cardamine leucantha. We applied a hierarchical Bayesian model to evaluate the effects of membership of a genet (a group of individuals clonally derived from a single seed and vegetation cover on the epigenetic variation between ramets (clonal plants that are physiologically independent individuals. We sampled 332 ramets in a 20 m × 20 m study plot that contained 137 genets (identified using eight SSR markers. We detected epigenetic variation in DNA methylation at 24 methylation-sensitive amplified fragment length polymorphism (MS-AFLP loci. There were significant genet effects at all 24 MS-AFLP loci in the distribution of subepiloci. Vegetation cover had no statistically significant effect on variation in the majority of MS-AFLP loci. The spatial aggregation of epigenetic variation is therefore largely explained by the aggregation of ramets that belong to the same genets. By applying hierarchical Bayesian analyses, we successfully identified a number of genet-specific changes in epigenetic status within a natural plant population in a complex context, where genotypes and environmental factors are unevenly distributed. This finding suggests that it requires further studies on the spatial epigenetic structure of natural populations of diverse organisms

  19. Genet-specific DNA methylation probabilities detected in a spatial epigenetic analysis of a clonal plant population.

    Science.gov (United States)

    Araki, Kiwako S; Kubo, Takuya; Kudoh, Hiroshi

    2017-01-01

    In sessile organisms such as plants, spatial genetic structures of populations show long-lasting patterns. These structures have been analyzed across diverse taxa to understand the processes that determine the genetic makeup of organismal populations. For many sessile organisms that mainly propagate via clonal spread, epigenetic status can vary between clonal individuals in the absence of genetic changes. However, fewer previous studies have explored the epigenetic properties in comparison to the genetic properties of natural plant populations. Here, we report the simultaneous evaluation of the spatial structure of genetic and epigenetic variation in a natural population of the clonal plant Cardamine leucantha. We applied a hierarchical Bayesian model to evaluate the effects of membership of a genet (a group of individuals clonally derived from a single seed) and vegetation cover on the epigenetic variation between ramets (clonal plants that are physiologically independent individuals). We sampled 332 ramets in a 20 m × 20 m study plot that contained 137 genets (identified using eight SSR markers). We detected epigenetic variation in DNA methylation at 24 methylation-sensitive amplified fragment length polymorphism (MS-AFLP) loci. There were significant genet effects at all 24 MS-AFLP loci in the distribution of subepiloci. Vegetation cover had no statistically significant effect on variation in the majority of MS-AFLP loci. The spatial aggregation of epigenetic variation is therefore largely explained by the aggregation of ramets that belong to the same genets. By applying hierarchical Bayesian analyses, we successfully identified a number of genet-specific changes in epigenetic status within a natural plant population in a complex context, where genotypes and environmental factors are unevenly distributed. This finding suggests that it requires further studies on the spatial epigenetic structure of natural populations of diverse organisms, particularly for

  20. Survey of population health in towns with nuclear and fossil fuel power plants

    International Nuclear Information System (INIS)

    Ivanov, E.; Shubik, V. M.

    2004-01-01

    Comparative assessment of population health in Sosnovy Bor with nuclear power plant and Kirovsk with fossil fuel power station was made for public and administration information. Both towns are located in Leningrad administrative region at 150 km distance from each other. In nuclear power town radiological situation was assessed as normal and in Kirovsk up to 1995 yr. with coal fuel, maximum permissible levels of suspended particle of sulfur oxide in atmosphere were exceeded in 6-9% of samples. After 1995 yr. the natural gas was used as fuel. Demographic data for 1991-2000 yrs indicate that mortality including infants mortality and stillborns was lower in Sosnovy Bor (NOS) then in Kirovsk (fossil fuel) and on average Leningrad administrative region. Birth rate and population growth was higher in Sosnovy Bor at the same time surprisingly the recorded morbidity was higher in Sosnovy Bor which might be explained by extensive medical supervision and improved diagnostics. However, cancer and tuberculosis morbidity was lower in Sosnovy Bor. In Kirovsk in 1997-2000 yrs. oncological morbidity was higher on average comparing to Leningrad administrative region. Oncological mortality in Sosnovy Bor in 1997-2000 yrs. was lower than in Kirovsk and Leningrad region Standardized annual mortality in Sosnovy Bor, Kirovsk and Leningrad administrative region was 128.3, 209.6 and 211.7 on 100 000 respectively. Health state of pregnant women, deliveries, new-born condition were all in normal range in Sosnovy Bor, contrary to higher increased abortion rate and pregnancy complications in Kirovsk. These findings need further studies. (Author)

  1. Survey of population health in towns with nuclear and fossil fuel power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, E.; Shubik, V. M.

    2004-07-01

    Comparative assessment of population health in Sosnovy Bor with nuclear power plant and Kirovsk with fossil fuel power station was made for public and administration information. Both towns are located in Leningrad administrative region at 150 km distance from each other. In nuclear power town radiological situation was assessed as normal and in Kirovsk up to 1995 yr. with coal fuel, maximum permissible levels of suspended particle of sulfur oxide in atmosphere were exceeded in 6-9% of samples. After 1995 yr. the natural gas was used as fuel. Demographic data for 1991-2000 yrs indicate that mortality including infants mortality and stillborns was lower in Sosnovy Bor (NOS) then in Kirovsk (fossil fuel) and on average Leningrad administrative region. Birth rate and population growth was higher in Sosnovy Bor at the same time surprisingly the recorded morbidity was higher in Sosnovy Bor which might be explained by extensive medical supervision and improved diagnostics. However, cancer and tuberculosis morbidity was lower in Sosnovy Bor. In Kirovsk in 1997-2000 yrs. oncological morbidity was higher on average comparing to Leningrad administrative region. Oncological mortality in Sosnovy Bor in 1997-2000 yrs. was lower than in Kirovsk and Leningrad region Standardized annual mortality in Sosnovy Bor, Kirovsk and Leningrad administrative region was 128.3, 209.6 and 211.7 on 100 000 respectively. Health state of pregnant women, deliveries, new-born condition were all in normal range in Sosnovy Bor, contrary to higher increased abortion rate and pregnancy complications in Kirovsk. These findings need further studies. (Author)

  2. Effects of Flavonoid-rich Plant Extracts on Ruminal Methanogenesis, Microbial Populations and Fermentation Characteristics

    Directory of Open Access Journals (Sweden)

    Eun T. Kim

    2015-04-01

    Full Text Available The objective of this study was to evaluate the in vitro effects of flavonoid-rich plant extracts (PE on ruminal fermentation characteristics and methane emission by studying their effectiveness for methanogenesis in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The PE (Punica granatum, Betula schmidtii, Ginkgo biloba, Camellia japonica, and Cudrania tricuspidata known to have high concentrations of flavonoid were added to an in vitro fermentation incubated with rumen fluid. Total gas production and microbial growth with all PE was higher than that of the control at 24 h incubation, while the methane emission was significantly lower (p<0.05 than that of the control. The decrease in methane accumulation relative to the control was 47.6%, 39.6%, 46.7%, 47.9%, and 48.8% for Punica, Betula, Ginkgo, Camellia, and Cudrania treatments, respectively. Ciliate populations were reduced by more than 60% in flavonoid-rich PE treatments. The Fibrobacter succinogenes diversity in all added flavonoid-rich PE was shown to increase, while the Ruminoccocus albus and R. flavefaciens populations in all PE decreased as compared with the control. In particular, the F. succinogenes community with the addition of Birch extract increased to a greater extent than that of others. In conclusion, the results of this study showed that flavonoid-rich PE decreased ruminal methane emission without adversely affecting ruminal fermentation characteristics in vitro in 24 h incubation time, suggesting that the flavonoid-rich PE have potential possibility as bio-active regulator for ruminants.

  3. Study on optimum aseismic design of complex structure system focusing on damping effect

    International Nuclear Information System (INIS)

    Takahashi, Yoshitaka; Suzuki, Kohei

    1995-01-01

    Optimum design technique for the purpose of aseismic design of complex plant structures such as piping and boiler structures is proposed. Particular attention is focused on the evaluation of the optimum damping and stiffness of the structures and components. Pseudo least square algorithm is introduced to determine the optimum design parameters. Under the requirement of certain allowable maximum response to a given earthquake excitation, optimum stiffness and damping values of the structure can be simultaneously calculated by this proposed method. The applicability of the method is demonstrated through three structural models; (1) linear multi-storied building model in which stiffness and damping constant of each floor are optimized; (2) nonlinear multi-storied building model having the isolated floor in which hysteretic energy absorber of the isolator is optimized; (3) combined boiler-supporting structure model connected by the inelastic seismic ties with each other is optimized. In this model, optimum values of damping characteristic of the seismic ties are evaluated. This work is particularly important for the aseismic design of complex plant structures like integrated boiler-supporting structure in thermal power plant and piping-containment vessel structure in nuclear power plant

  4. EPR pilot study on the population of Stepnogorsk city living in the vicinity of a uranium processing plant

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, Kassym; Akilbekov, Abdirash; Morzabayev, Aidar [L.N. Gumilyov Eurasian National University, Astana (Kazakhstan); Ivannikov, Alexander; Stepanenko, Valeriy [Medical Radiological Research Center, Obninsk (Russian Federation); Abralina, Sholpan; Sadvokasova, Lyazzat; Rakhypbekov, Tolebay [Semey State Medical University, Semey (Kazakhstan); Hoshi, Masaharu [Hiroshima University, Research Institute for Radiation Biology and Medicine, Hiroshima (Japan)

    2015-03-15

    The aim of this pilot study was to evaluate possible doses in teeth received by workers of a uranium processing plant, in excess to the natural background dose. For this, the electron paramagnetic resonance dosimetry method was applied. Absorbed doses in teeth from the workers were compared with those measured in teeth from the Stepnogorsk city population and a control pool population from Astana city. The measured tooth samples were extracted according to medical indications. In total, 32 tooth enamel samples were analyzed, 5 from Astana city, Kazakhstan (control population), 21 from the residents of Stepnogorsk city (180 km from Astana city), and 6 from the workers of a uranium processing plant. The estimated doses in tooth enamel from the uranium processing plant workers were not significantly different to those measured in enamel from the control population. In teeth from the workers, the maximum dose in excess to background dose was 33 mGy. In two teeth from residents of Stepnogorsk city, however, somewhat larger doses were measured. The results of this pilot study encourage further investigations in an effort to receiving a final conclusion on the exposure situation of the uranium processing plant workers and the residents of Stepnogorsk city. (orig.)

  5. Current use of wild plants with edible underground storage organs in a rural population of Patagonia: between tradition and change.

    Science.gov (United States)

    Ochoa, Juan José; Ladio, Ana Haydee

    2015-09-25

    Edible plants with underground storage organs (USOs) are neglected resources. We studied the local ecological knowledge edible plants with (USOs) in rural populations of North-Patagonia in order to establish how people are utilizing these plants. Some aspect of corpus-praxis-cosmos complex associated to the local ecological knowledge was documented and discussed. In addition, variation in this ecological knowledge due to age, gender, family structure, ethnic self-determination was also evaluated. Semi-structured interviews were conducted with 51 inhabitants in order to study the relationship between the current use of plants with USOs and the age, sex, family group composition and ethnic self-identification of interviewees. In addition, the Cultural Importance Index for each species was calculated. The current richness of known species in these populations is a total of 9 plants. Plants with USOs tend to be used more frequently as the age of the interviewee increases. Women and men showed no differences in the average richness of species cited. The interviewees who share their homes with other generations use these plants more frequently than those who live alone. Our results indicate that the interviewees who identified themselves as belonging to the Mapuche people use these plants more frequently. For the Mapuche people, wild plants have constituted material and symbolic resources of great importance in their historical subsistence. In addition, they are currently being redefined as elements which present a connection with ancestral practices, produce a strong relationship with the 'land', and become markers which identify the 'natural' (historical) ways of their people; these are key elements in the current political processes of identity revaluation. This research is valuable to stimulate cultural revival and health promotion programs in the communities with their own local, cultural food.

  6. Mate Limitation in Fungal Plant Parasites Can Lead to Cyclic Epidemics in Perennial Host Populations.

    Science.gov (United States)

    Ravigné, Virginie; Lemesle, Valérie; Walter, Alicia; Mailleret, Ludovic; Hamelin, Frédéric M

    2017-03-01

    Fungal plant parasites represent a growing concern for biodiversity and food security. Most ascomycete species are capable of producing different types of infectious spores both asexually and sexually. Yet the contributions of both types of spores to epidemiological dynamics have still to been fully researched. Here we studied the effect of mate limitation in parasites which perform both sexual and asexual reproduction in the same host. Since mate limitation implies positive density dependence at low population density, we modeled the dynamics of such species with both density-dependent (sexual) and density-independent (asexual) transmission rates. A first simple SIR model incorporating these two types of transmission from the infected compartment, suggested that combining sexual and asexual spore production can generate persistently cyclic epidemics in a significant part of the parameter space. It was then confirmed that cyclic persistence could occur in realistic situations by parameterizing a more detailed model fitting the biology of the Black Sigatoka disease of banana, for which literature data are available. We discuss the implications of these results for research on and management of Sigatoka diseases of banana.

  7. Psidium guajava: A Single Plant for Multiple Health Problems of Rural Indian Population.

    Science.gov (United States)

    Daswani, Poonam G; Gholkar, Manasi S; Birdi, Tannaz J

    2017-01-01

    The rural population in India faces a number of health problems and often has to rely on local remedies. Psidium guajava Linn. (guava), a tropical plant which is used as food and medicine can be used by rural communities due to its several medicinal properties. A literature search was undertaken to gauge the rural health scenario in India and compile the available literature on guava so as to reflect its usage in the treatment of multiple health conditions prevalent in rural communities. Towards this, electronic databases such as Pubmed, Science Direct, google scholar were scanned. Information on clinical trials on guava was obtained from Cochrane Central Register of Controlled Trials and Clinicaltrial.gov. The literature survey revealed that guava possesses various medicinal properties which have been reported from across the globe in the form of ethnobotanical/ethnopharmacological surveys, laboratory investigations and clinical trials. Besides documenting the safety of guava, the available literature shows that guava is efficacious against the following conditions which rural communities would encounter. (a) Gastrointestinal infections; (b) Malaria; (c)Respiratory infections; (d) Oral/dental infections; (e) Skin infections; (f) Diabetes; (g) Cardiovascular/hypertension; (h) Cancer; (i) Malnutrition; (j) Women problems; (k) Pain; (l) Fever; (m) Liver problems; (n) Kidney problems. In addition, guava can also be useful for treatment of animals and explored for its commercial applications. In conclusion, popularization of guava, can have multiple applications for rural communities.

  8. Reproductive allocation strategies in desert and Mediterranean populations of annual plants grown with and without water stress.

    Science.gov (United States)

    Aronson, J; Kigel, J; Shmida, A

    1993-03-01

    Reproductive effort (relative allocation of biomass to diaspore production) was compared in matched pairs of Mediterranean and desert populations of three unrelated annual species, Erucaria hispanica (L.) Druce, Bromus fasciculatus C. Presl. and Brachypodium distachyon (L.) Beauv., grown under high and low levels of water availability in a common-environment experiment. Desert populations in all three species showed higher reproductive effort than corresponding Mediterranean populations, as expressed by both a reproductive index (RI= reproductive biomass/vegetative biomass), and a reproductive efficiency index (REI=number of diaspores/total plant biomass). Moreover, in E. hispanica and Brachypodium distachyon, inter-populational differences in reproductive effort were greater under water stress, the main limiting factor for plant growth in the desert. These results indicate that variability in reproductive effort in response to drought is a critical and dynamic component of life history strategies in annual species in heterogeneous, unpredictable xeric environments. When subjected to water stress the Mediterranean populations of E. hispanica and B. distachyon showed greater plasticity (e.g. had a greater reduction) in reproductive effort than the desert populations, while in Bromus fasciculatus both populations showed similar amounts of plasticity.

  9. Pseudohypericin and Hyperforin in Hypericum perforatum from Northern Turkey: Variation among Populations, Plant Parts and Phenological Stages

    Institute of Scientific and Technical Information of China (English)

    Cüneyt ?irak; Jolita Radusiene; Valdimaras Janulis; Liudas Ivanauskas

    2008-01-01

    Hypericum perforatum is a perennial medicinal plant known as "St. John's wort" in Western Europe and has been used in the treatment of several diseases for centuries. In the present study, morphologic, phenologic and population variability in pseudohypericin and hyperforin concentrations among H. perforatum populations from Northern Turkey was investigated for the first time. The aerial parts of H. perforatum plants representing a total of 30 individuals were collected at full flowering from 10 sites of Northern Turkey to search the regional variation in the secondary metabolits concentrations. For morphologic and phenologic sampling, plants from one site were gathered in five phenological stages: vegetative,floral budding, full flowering, fresh fruiting and mature fruiting. The plant materials were air-dried at room temperature and subsequently assayed for chemical concentrations by high performance liquid chromatography. Secondary metabolite concentrations ranged from traces to 2.94mg/g dry weight (DW) for pseudohypedcin and traces -6.29mg/g DW for hyperforin. The differences in the secondary metabolite concentrations among populations of H. perforatum were found to be significant. The populations varied greatly in hyperforin concentrations, whereas they produced a similar amount of pseudohypericin. Concentrations of both secondary metabolites in all tissues increased with advancing of plant development and higher accumulation levels were reached at flowering. Among different tissues, full opened flowers were found to be superior to stems, leaves and the other reproductive parts with regard to pseudohypericin and hyperforin accumulations. The present findings might be useful to optimize the processing methodology of wild-harvested plant material and obtain Increased concentrations of these secondary metabolites.

  10. Effect of plant population density on the growth and yield of sorghum ...

    African Journals Online (AJOL)

    Improvement of resource use efficiency and yields is probably possible through the use of appropriate plant densities. Field trials were therefore conducted to study the effects of four plant densities, varying from 2.0 to 12.5 plants m-2 on water and radiation use and performance of two Masakwa sorghum varieties grown on ...

  11. Using functional-structural plant modeling to explore the response of cotton to mepiquat chloride application and plant population density

    NARCIS (Netherlands)

    Gu, S.; Evers, J.B.; Zhang, L.; Mao, L.; Vos, J.; Li, Z.

    2013-01-01

    The crop growth regulator Mepiquat Chloride (MC) is widely used in cotton production to optimize the canopy structure in order to maximize the yield and fiber quality. Cotton plasticity in relation to MC and other agronomical practice was quantified using a functional-structural plant model of

  12. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas.

    Science.gov (United States)

    van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

    2016-06-01

    The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant's lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant-plant interactions was analysed. Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant-plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly driven by plastic and not by genotypic responses to changes in

  13. Optimum Operational Parameters for Yawed Wind Turbines

    Directory of Open Access Journals (Sweden)

    David A. Peters

    2011-01-01

    Full Text Available A set of systematical optimum operational parameters for wind turbines under various wind directions is derived by using combined momentum-energy and blade-element-energy concepts. The derivations are solved numerically by fixing some parameters at practical values. Then, the interactions between the produced power and the influential factors of it are generated in the figures. It is shown that the maximum power produced is strongly affected by the wind direction, the tip speed, the pitch angle of the rotor, and the drag coefficient, which are specifically indicated by figures. It also turns out that the maximum power can take place at two different optimum tip speeds in some cases. The equations derived herein can also be used in the modeling of tethered wind turbines which can keep aloft and deliver energy.

  14. OPTIMUM PROGRAMMABLE CONTROL OF UNMANNED FLYING VEHICLE

    Directory of Open Access Journals (Sweden)

    A. А. Lobaty

    2012-01-01

    Full Text Available The paper considers an analytical synthesis problem pertaining to programmable control of an unmanned flying vehicle while steering it to the fixed space point. The problem has been solved while applying a maximum principle which takes into account a final control purpose and its integral expenses. The paper presents an optimum law of controlling overload variation of a flying vehicle that has been obtained analytically

  15. Techniques for evaluating optimum data center operation

    Science.gov (United States)

    Hamann, Hendrik F.; Rodriguez, Sergio Adolfo Bermudez; Wehle, Hans-Dieter

    2017-06-14

    Techniques for modeling a data center are provided. In one aspect, a method for determining data center efficiency is provided. The method includes the following steps. Target parameters for the data center are obtained. Technology pre-requisite parameters for the data center are obtained. An optimum data center efficiency is determined given the target parameters for the data center and the technology pre-requisite parameters for the data center.

  16. Probabilistic studies for safety at optimum cost

    International Nuclear Information System (INIS)

    Pitner, P.

    1999-01-01

    By definition, the risk of failure of very reliable components is difficult to evaluate. How can the best strategies for in service inspection and maintenance be defined to limit this risk to an acceptable level at optimum cost? It is not sufficient to design structures with margins, it is also essential to understand how they age. The probabilistic approach has made it possible to develop well proven concepts. (author)

  17. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2 : an experiment with plant populations from naturally high CO2 areas

    NARCIS (Netherlands)

    van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may

  18. The optimum lead thickness for lead-activation detectors

    International Nuclear Information System (INIS)

    Si Fenni; Hu Qingyuan

    2009-01-01

    The optimum lead thickness for lead-activation detectors has been studied in this paper. First existence of the optimum lead thickness is explained theoretically. Then the optimum lead thickness is obtained by two methods, MCNP5 calculation and mathematical estimation. At last factors which affect the optimum lead thickness are discussed. It turns out that the optimum lead thickness is irrelevant to incident neutron energies. It is recommended 2.5 cm generally.

  19. Population densities of indigenous Acidobacteria change in the presence of plant growth promoting rhizobacteria (PGPR) in rhizosphere.

    Science.gov (United States)

    Kalam, Sadaf; Das, Subha Narayan; Basu, Anirban; Podile, Appa Rao

    2017-05-01

    Rhizosphere microbial community has diverse metabolic capabilities and plays a crucial role in maintaining plant health. Oligotrophic plant growth promoting rhizobacteria (PGPR), along with difficult-to-culture microbial fractions, might be involved synergistically in microbe-microbe and plant-microbe interactions in the rhizosphere. Among the difficult-to-culture microbial fractions, Acidobacteria constitutes the most dominant phylum thriving in rhizospheric soils. We selected effective PGPR for tomato and black gram and studied their effect on population densities of acidobacterial members. Three facultatively oligotrophic PGPR were identified through 16S rRNA gene sequencing as Sphingobacterium sp. (P3), Variovorax sp. (P4), and Roseomonas sp. (A2); the latter being a new report of PGPR. In presence of selected PGPR strains, the changes in population densities of Acidobacteria were monitored in metagenomic DNA extracted from bulk and rhizospheric soils of tomato and black gram using real time qPCR. A gradual increase in equivalent cell numbers of Acidobacteria members was observed over time along with a simultaneous increase in plant growth promotion by test PGPR. We report characterization of three effective PGPR strains and their effects on indigenous, underexplored difficult-to-culture phylum-Acidobacteria. We suggest that putative interactions between these two bacterial groups thriving in rhizospheric soils could be beneficial for plant growth. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Population morbidity in the Zaporizhzhia Nuclear Power Plant observation zone as an integral part of public health.

    Science.gov (United States)

    Khomenko, I M; Zakladna, N V; Orlova, N M

    2017-12-01

    To evaluate the health status of adult population living in the Ukrainian nuclear power industry obser vation zone on the example of Zaporizhzhia Nuclear Power Plant. System review, analytic, sociological survey and statistical methods. There was established an increase in the incidence of digestive diseases among adult population in Nikopol of Dnipropetrovsk region, which is included in the Zaporizhzhia NPP observation zone. The highest increase was observed in the incidence of peptic ulcer, gastritis and duodenitis, cholecystitis and cholangitis by 340 %, 305 % and 83 %, respectively. In connection with the residence in industrially developed region and NPP life extension in Ukraine, the possible influence of harmful factors on health status of the population of observation zones, an increase in the incidence of digestive diseases among adult population, there is required continuous monitoring and detailed study of public health. I. M. Khomenko, N. V. Zakladna, N. M. Orlova.

  1. Varying Herbivore Population Structure Correlates with Lack of Local Adaptation in a Geographic Variable Plant-Herbivore Interaction

    Science.gov (United States)

    Cogni, Rodrigo; Trigo, José R.; Futuyma, Douglas J.

    2011-01-01

    Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host plant, the pyrrolizidine alkaloid-bearing legume Crotalaria pallida, at the continental scale, but found no differentiation at the regional scale. In the present study, we sampled the same sites to investigate factors that may contribute to the lack of differentiation at the regional scale. We performed field observations that show that specialist and non-specialist polyphagous herbivore incidence varies among populations at both scales. With a series of common-garden experiments we show that some plant traits that may affect herbivory (pyrrolizidine alkaloids and extrafloral nectaries) vary at the regional scale, while other traits (trichomes and nitrogen content) just vary at the continental scale. These results, combined with our previous evidence for plant population differentiation based on larval performance on fresh fruits, suggest that U. ornatrix is subjected to divergent selection even at the regional scale. Finally, with a microsatellite study we investigated population structure of U. ornatrix. We found that population structure is not stable over time: we found population differentiation at the regional scale in the first year of sampling, but not in the second year. Unstable population structure of the herbivore is the most likely cause of the lack of regional adaptation. PMID:22220208

  2. Varying herbivore population structure correlates with lack of local adaptation in a geographic variable plant-herbivore interaction.

    Directory of Open Access Journals (Sweden)

    Rodrigo Cogni

    Full Text Available Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host plant, the pyrrolizidine alkaloid-bearing legume Crotalaria pallida, at the continental scale, but found no differentiation at the regional scale. In the present study, we sampled the same sites to investigate factors that may contribute to the lack of differentiation at the regional scale. We performed field observations that show that specialist and non-specialist polyphagous herbivore incidence varies among populations at both scales. With a series of common-garden experiments we show that some plant traits that may affect herbivory (pyrrolizidine alkaloids and extrafloral nectaries vary at the regional scale, while other traits (trichomes and nitrogen content just vary at the continental scale. These results, combined with our previous evidence for plant population differentiation based on larval performance on fresh fruits, suggest that U. ornatrix is subjected to divergent selection even at the regional scale. Finally, with a microsatellite study we investigated population structure of U. ornatrix. We found that population structure is not stable over time: we found population differentiation at the regional scale in the first year of sampling, but not in the second year. Unstable population structure of the herbivore is the most likely cause of the lack of regional adaptation.

  3. Siting of Nuclear Power Plants in Metropolitan Areas. Estimation of Population Doses due to Accidental Release of Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Bresser, H. [Technischer Ueberwachungs-Verein Rheinland E.V., Cologne (Germany); Schwarzer, W. [Institut fuer Reaktorsicherheit der Technischen Ueberwachungs-Vereine E.V., Cologne (Germany)

    1967-09-15

    The safety of large nuclear power plants in heavily populated areas depends entirely on engineered safeguards. An assessment of their reliability and effectiveness will have to play a major role in any safety analysis of such a plant, and this assessment will have to be made on the basis of the radiological burden to the environment - in terms of individual dose and a population dose - which can be accepted as tolerable in case of a severe accident. The calculation of the dispersion of fission products in the atmosphere, which links the radiological burden to the release of radioactivity, should be modified. The fact that distance factors, aside from a comparably small exclusion area, can no longer be taken into account suggests the introduction of the parameter ''population density'' and an extensive use of the man-rem concept. In this connection the time history of the release and the influence of variations of wind directions lose their importance. The authors have carried out calculations of the population dose, which could be received in a metropolitan area as a consequence of a severe reactor accident, using population densities, height of release above ground and generalized meteorological data as the main parameters. The results of these calculations are used as a basis for an assessment of the performance requirements of the engineered safeguards system, and the relative importance of different components of this system is discussed. (author)

  4. Nitrogen and plant population change radiation capture and utilization capacity of sunflower in semi-arid environment.

    Science.gov (United States)

    Awais, Muhammad; Wajid, Aftab; Bashir, Muhammad Usman; Habib-Ur-Rahman, Muhammad; Raza, Muhammad Aown Sammar; Ahmad, Ashfaq; Saleem, Muhammad Farrukh; Hammad, Hafiz Mohkum; Mubeen, Muhammad; Saeed, Umer; Arshad, Muhammad Naveed; Fahad, Shah; Nasim, Wajid

    2017-07-01

    The combination of nitrogen and plant population expresses the spatial distribution of crop plants. The spatial distribution influences canopy structure and development, radiation capture, accumulated intercepted radiation (Sa), radiation use efficiency (RUE), and subsequently dry matter production. We hypothesized that the sunflower crop at higher plant populations and nitrogen (N) rates would achieve early canopy cover, capture more radiant energy, utilize radiation energy more efficiently, and ultimately increase economic yield. To investigate the above hypothesis, we examined the influences of leaf area index (LAI) at different plant populations (83,333, 66,666, and 55,555 plants ha -1 ) and N rates (90, 120, and 150 kg ha -1 ) on radiation interception (Fi), photosynthetically active radiation (PAR) accumulation (Sa), total dry matter (TDM), achene yield (AY), and RUE of sunflower. The experimental work was conducted during 2012 and 2013 on sandy loam soil in Punjab, Pakistan. The sunflower crop captured more than 96% of incident radiant energy (mean of all treatments), 98% with a higher plant population (83,333 plants ha -1 ), and 97% with higher N application (150 kg ha -1 ) at the fifth harvest (60 days after sowing) during both study years. The plant population of 83,333 plants ha -1 with 150 kg N ha -1 ominously promoted crop, RUE, and finally productivity of sunflower (AY and TDM). Sunflower canopy (LAI) showed a very close and strong association with Fi (R 2  = 0.99 in both years), PAR (R 2  = 0.74 and 0.79 in 2012 and 2013, respectively), TDM (R 2  = 0.97 in 2012 and 0.91 in 2013), AY (R 2  = 0.95 in both years), RUE for TDM (RUE TDM ) (R 2  = 0.63 and 0.71 in 2012 and 2013, respectively), and RUE for AY (RUE AY ) (R 2  = 0.88 and 0.87 in 2012 and 2013, respectively). Similarly, AY (R 2  = 0.73 in 2012 and 0.79 in 2013) and TDM (R 2  = 0.75 in 2012 and 0.84 in 2013) indicated significant dependence on PAR accumulation of

  5. Medicinal plants of Papua New Guinea's Miu speaking population and a focus on their use of plant-slaked lime mixtures.

    Science.gov (United States)

    Prescott, Thomas A K; Briggs, Marie; Kiapranis, Robert; Simmonds, Monique S J

    2015-11-04

    Here we present the results of an ethnobotanical survey of the medicinal plants used by the Miu, a virtually unresearched ethnolinguistic group who live in the mountainous interior of Papua New Guinea's West New Britain Province. We compare the findings for those previously reported for the neighbouring inland Kaulong speaking population. Three species, Trema orientalis, Spondias dulcis and Ficus botryocarpa are used in combination with locally prepared slaked lime to produce intensely coloured mixtures which are applied to dermatological infections. Their effects on dermal fibroblast viability with and without slaked lime are examined. The sap of F. botryocarpa which is used to treat tropical ulcers was examined further with assays relevant to wound healing. Focus groups and semi-structured interviews were used to acquire information on the uses of plants, vouchers of which were collected and identified by comparison with authentic herbarium specimens. LC-MS and NMR were used to identify chemical components. Cell viability assays were used to examine the effects of added slaked lime on dermal fibroblasts. For the sap of F. botryocarpa, fibroblast stimulation assays and antibacterial growth inhibition with Bacillus subtilis were carried out. The survey identified 33 plants and one fungal species, and clear differences with the inland Kaulong group despite their close proximity. Added slaked lime does not greatly increase the cytotoxicity of plant material towards dermal fibroblasts. The sap of F. botryocarpa contains the alkaloid ficuseptine as a single major component and displays antibacterial activity. The results demonstrate the potential for variation in medicinal plant use amongst Papua New Guinea's numerous language groups. The addition of slaked lime to plant material does not appear to present a concern for wound healing in the amounts used. The sap of F. botryocarpa displays antibacterial activity at concentrations that would occur at the wound surface

  6. Effects of plant density on forage production in five populations of ...

    African Journals Online (AJOL)

    Kleingrass (Panicum coloratum L.) forage yield evaluation plots are often established at a density of 6.0 plants m-2 to accommodate mechanical transplanting and harvesting equipment. However, forage crops are usually established from seed at higher plant densities. Experiments were conducted to determine if ...

  7. Are population differences in plant quality reflected in the preference and performance of two endoparasitoid wasps?

    NARCIS (Netherlands)

    Gols, R.; Dam, van N.M.; Raaijmakers, C.E.; Dicke, M.; Harvey, J.A.

    2009-01-01

    In recent years, increasing attention has been paid in exploring the role of direct plant defence, through the production of allelochemicals, on the performance of parasitoid wasps and their hosts. However, few studies have determined if parasitoids can detect differences in plant quality and thus

  8. Cancer incidence in the vicinity of nuclear power plants in Taiwan: a population-based study.

    Science.gov (United States)

    Wang, Shiow-Ing; Yaung, Chih-Liang; Lee, Long-Teng; Chiou, Shang-Jyh

    2016-01-01

    Numerous antinuclear demonstrations reveal that the public is anxious about the potential health effects caused by nuclear power plants. The purpose of this study is to address the question "Is there a higher cancer incidence rate in the vicinity of nuclear power plants in Taiwan?" The Taiwan Cancer Registry database from 1979 to 2003 was used to compare the standardized incidence rate of the top four cancers with strong evidence for radiation risks between the "plant-vicinity" with those "non-plant-vicinity" groups. All cancer sites, five-leading cancers in Taiwan, and gender-specific cancers were also studied. We also adopted different observation time to compare the incidence rate of cancers between two groups to explore the impact of the observation period. The incidences of leukemia, thyroid, lung, and breast cancer were not significantly different between two groups, but cervix uteri cancer showed higher incidence rates in the plant-vicinity group. The incidence of cervical cancer was not consistently associated with the duration of plant operation, according to a multiyear period comparison. Although there was higher incidence in cervix cancer in the plant-vicinity group, our findings did not provide the crucial evidence that nuclear power plants were the causal factor for some cancers with strong evidence for radiation risks.

  9. Rates of change in climatic niches in plant and animal populations are much slower than projected climate change

    Science.gov (United States)

    Jezkova, Tereza

    2016-01-01

    Climate change may soon threaten much of global biodiversity. A critical question is: can species undergo niche shifts of sufficient speed and magnitude to persist within their current geographic ranges? Here, we analyse niche shifts among populations within 56 plant and animal species using time-calibrated trees from phylogeographic studies. Across 266 phylogeographic groups analysed, rates of niche change were much slower than rates of projected climate change (mean difference > 200 000-fold for temperature variables). Furthermore, the absolute niche divergence among populations was typically lower than the magnitude of projected climate change over the next approximately 55 years for relevant variables, suggesting the amount of change needed to persist may often be too great, even if these niche shifts were instantaneous. Rates were broadly similar between plants and animals, but especially rapid in some arthropods, birds and mammals. Rates for temperature variables were lower at lower latitudes, further suggesting that tropical species may be especially vulnerable to climate change. PMID:27881748

  10. Thermal Comfort and Optimum Humidity Part 1

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  11. Thermal Comfort and Optimum Humidity Part 2

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  12. Plant recolonization in the Himalaya from the southeastern Qinghai-Tibetan Plateau: Geographical isolation contributed to high population differentiation.

    Science.gov (United States)

    Cun, Yu-Zhi; Wang, Xiao-Quan

    2010-09-01

    The Himalaya-Hengduan Mountains region (HHM) in the southern and southeastern Qinghai-Tibetan Plateau (QTP) is considered an important reservoir and a differentiation center for temperate and alpine plants in the Cenozoic. To reveal how plants responded to the Quaternary climatic oscillations in the QTP, the phylogeographical histories of a few subalpine and alpine plants have been investigated, but nearly all studies used only uniparentally inherited cytoplasmic DNA markers, and only a couple of them included sampling from the Himalaya. In this study, range-wide genetic variation of the Himalayan hemlock (Tsuga dumosa), an important forest species in the HHM, was surveyed using DNA markers from three genomes. All markers revealed genetic depauperation in the Himalaya and richness in the Hengduan Mountains populations. Surprisingly, population differentiation of this wind-pollinated conifer is very high in all three genomes, with few common and many private nuclear gene alleles. These results, together with fossil evidence, clearly indicate that T. dumosa recolonized the Himalaya from the Hengduan Mountains before the Last Glacial Maximum (LGM), accompanied with strong founder effects, and the influence of the earlier glaciations on demographic histories of the QTP plants could be much stronger than that of the LGM. The strong population differentiation in T. dumosa could be attributed to restricted gene flow caused by the complicated topography in the HHM that formed during the uplift of the QTP, and thus sheds lights on the importance of geographical isolation in the development of high plant species diversity in this biodiversity hotspot. Copyright 2010 Elsevier Inc. All rights reserved.

  13. Population survey of phytoseiid mites and spider mites on peach leaves and wild plants in Japanese peach orchard.

    Science.gov (United States)

    Wari, David; Yamashita, Jun; Kataoka, Yoko; Kohara, Yoko; Hinomoto, Norihide; Kishimoto, Hidenari; Toyoshima, Shingo; Sonoda, Shoji

    2014-07-01

    A population survey of phytoseiid mites and spider mites was conducted on peach leaves and wild plants in Japanese peach orchards having different pesticide practices. The phytoseiid mite species composition on peach leaves and wild plants, as estimated using quantitative sequencing, changed during the survey period. Moreover, it varied among study sites. The phytoseiid mite species compositions were similar between peach leaves and some wild plants, such as Veronica persica, Paederia foetida, Persicaria longiseta, and Oxalis corniculata with larger quantities of phytoseiid mites, especially after mid-summer. A PCR-based method to detect the ribosomal ITS sequences of Tetranychus kanzawai and Panonychus mori from phytoseiid mites was developed. Results showed that Euseius sojaensis (specialized pollen feeder/generalist predator) uses both spider mites as prey in the field.

  14. Design issues for optimum solar cell configuration

    Science.gov (United States)

    Kumar, Atul; Thakur, Ajay D.

    2018-05-01

    A computer based simulation of solar cell structure is performed to study the optimization of pn junction configuration for photovoltaic action. The fundamental aspects of photovoltaic action viz, absorption, separation collection, and their dependence on material properties and deatails of device structures is discussed. Using SCAPS 1D we have simulated the ideal pn junction and shown the effect of band offset and carrier densities on solar cell performance. The optimum configuration can be achieved by optimizing transport of carriers in pn junction under effect of field dependent recombination (tunneling) and density dependent recombination (SRH, Auger) mechanisms.

  15. Ideotype population exploration: growth, photosynthesis, and yield components at different planting densities in winter oilseed rape (Brassica napus L.).

    Science.gov (United States)

    Ma, Ni; Yuan, Jinzhan; Li, Ming; Li, Jun; Zhang, Liyan; Liu, Lixin; Naeem, Muhammad Shahbaz; Zhang, Chunlei

    2014-01-01

    Rapeseed is one of the most important edible oil crops in the world and the seed yield has lagged behind the increasing demand driven by population growth. Winter oilseed rape (Brassica napus L.) is widely cultivated with relatively low yield in China, so it is necessary to find the strategies to improve the expression of yield potential. Planting density has great effects on seed yield of crops. Hence, field experiments were conducted in Wuhan in the Yangtze River basin with one conventional variety (Zhongshuang 11, ZS11) and one hybrid variety (Huayouza 9, HYZ9) at five planting densities (27.0×10(4), 37.5×10(4), 48.0×10(4), 58.5×10(4), 69.0×10(4) plants ha(-1)) during 2010-2012 to investigate the yield components. The physiological traits for high-yield and normal-yield populations were measured during 2011-2013. Our results indicated that planting densities of 58.5×10(4) plants ha(-1) in ZS11 and 48.0×10(4) plants ha(-1) in HYZ9 have significantly higher yield compared with the density of 27.0×10(4) plants ha(-1) for both varieties. The ideal silique numbers for ZS11 and HYZ9 were ∼0.9×10(4) (n m(-2)) and ∼1×10(4) (n m(-2)), respectively, and ideal primary branches for ZS11 and HYZ9 were ∼250 (n m(-2)) and ∼300 (n m(-2)), respectively. The highest leaf area index (LAI) and silique wall area index (SAI) was ∼5.0 and 7.0, respectively. Moreover, higher leaf net photosynthetic rate (Pn) and water use efficiency (WUE) were observed in the high-yield populations. A significantly higher level of silique wall photosynthesis and rapid dry matter accumulation were supposed to result in the maximum seed yield. Our results suggest that increasing the planting density within certain range is a feasible approach for higher seed yield in winter rapeseed in China.

  16. Assessing power plant impacts on fish populations at Northeast Utilities sites: winter flounder studies at Millstone Nuclear Power Station

    International Nuclear Information System (INIS)

    Lorda, E.; Danila, D.J.; Miller, J.D.; Bireley, L.E.; Jacobsen, P.M.

    1987-01-01

    An historical view is presented of the various impact assessment approaches used to study the winter flounder, including efforts to identify and quantify compensation and to model its population dynamics. This review illustrates the need for unbiased estimates of basic life history parameters and power plant related mortalities if compensatory mechanisms are to be understood and if impact assessments are to be meaningful. 67 references, 19 figures, 10 tables

  17. Plantes médicinales utilisées par les populations Bassa de la région ...

    African Journals Online (AJOL)

    Une enquête ethnobotanique portant sur un échantillon de 90 ménages a été conduite en juin 2010 dans trois villages de la région de Douala, au Cameroun, afin de recenser les plantes médicinales utilisées par les populations rurales. Elle montre que 48 espèces relevant de 44 genres et de 26 familles sont utilisées dans ...

  18. Optimum fuel allocation in parallel steam generator systems

    International Nuclear Information System (INIS)

    Bollettini, U.; Cangioli, E.; Cerri, G.; Rome Univ. 'La Sapienza'; Trento Univ.

    1991-01-01

    An optimization procedure was developed to allocate fuels into parallel steam generators. The procedure takes into account the level of performance deterioration connected with the loading history (fossil fuel allocation and maintenance) of each steam generator. The optimization objective function is the system hourly cost, overall steam demand being satisfied. Costs are due to fuel and electric power supply and to plant depreciation and maintenance as well. In order to easily updata the state of each steam generator, particular care was put in the general formulation of the steam production function by adopting a special efficiency-load curve description based on a deterioration scaling parameter. The influence of the characteristic time interval length on the optimum operation result is investigated. A special implementation of the method based on minimum cost paths is suggested

  19. Optimum selection of an energy resource using fuzzy logic

    International Nuclear Information System (INIS)

    Abouelnaga, Ayah E.; Metwally, Abdelmohsen; Nagy, Mohammad E.; Agamy, Saeed

    2009-01-01

    Optimum selection of an energy resource is a vital issue in developed countries. Considering energy resources as alternatives (nuclear, hydroelectric, gas/oil, and solar) and factors upon which the proper decision will be taken as attributes (economics, availability, environmental impact, and proliferation), one can use the multi-attribute utility theory (MAUT) to optimize the selection process. Recently, fuzzy logic is extensively applied to the MAUT as it expresses the linguistic appraisal for all attributes in wide and reliable manners. The rise in oil prices and the increased concern about environmental protection from CO 2 emissions have promoted the attention to the use of nuclear power as a viable energy source for power generation. For Egypt, as a case study, the nuclear option is found to be an appropriate choice. Following the introduction of innovative designs of nuclear power plants, improvements in the proliferation resistance, environmental impacts, and economics will enhance the selection of the nuclear option.

  20. Murray's law, the "Yarrum'" optimum, and the hydraulic architecture of compound leaves

    Science.gov (United States)

    Katherine A. McCulloh; John S. Sperry; Frederick C. Meinzer; Barbara Lachenbruch; Cristian. Atala

    2009-01-01

    There are two optima for maximizing hydraulic conductance per vasculature volume in plants. Murray's law (ML) predicts the optimal conduit taper for a fixed change in conduit number across branch ranks. The opposite, the Yarrum optimum (YO), predicts the optimal change in conduit number for a fixed taper. We derived the solution for YO and then evaluated...

  1. Genetic diversity and population structure in Polygonum cespitosum: insights to an ongoing plant invasion.

    Directory of Open Access Journals (Sweden)

    Silvia Matesanz

    Full Text Available Molecular markers can help elucidate how neutral evolutionary forces and introduction history contribute to genetic variation in invaders. We examined genetic diversity, population structure and colonization patterns in the invasive Polygonum cespitosum, a highly selfing, tetraploid Asian annual introduced to North America. We used nine diploidized polymorphic microsatellite markers to study 16 populations in the introduced range (northeastern North America, via the analyses of 516 individuals, and asked the following questions: 1 Do populations have differing levels of within-population genetic diversity? 2 Do populations form distinct genetic clusters? 3 Does population structure reflect either geographic distances or habitat similarities? We found low heterozygosity in all populations, consistent with the selfing mating system of P. cespitosum. Despite the high selfing levels, we found substantial genetic variation within and among P. cespitosum populations, based on the percentage of polymorphic loci, allelic richness, and expected heterozygosity. Inferences from individual assignment tests (Bayesian clustering and pairwise FST values indicated high among-population differentiation, which indicates that the effects of gene flow are limited relative to those of genetic drift, probably due to the high selfing rates and the limited seed dispersal ability of P. cespitosum. Population structure did not reflect a pattern of isolation by distance nor was it related to habitat similarities. Rather, population structure appears to be the result of the random movement of propagules across the introduced range, possibly associated with human dispersal. Furthermore, the high population differentiation, genetic diversity, and fine-scale genetic structure (populations founded by individuals from different genetic sources in the introduced range suggest that multiple introductions to this region may have occurred. High genetic diversity may further

  2. Population genetic structure of rare and endangered plants using molecular markers

    Science.gov (United States)

    Raji, Jennifer; Atkinson, Carter T.

    2013-01-01

    This study was initiated to assess the levels of genetic diversity and differentiation in the remaining populations of Phyllostegia stachyoides and Melicope zahlbruckneri in Hawai`i Volcanoes National Park and determine the extent of gene flow to identify genetically distinct individuals or groups for conservation purposes. Thirty-six Amplified Fragment Length Polymorphic (AFLP) primer combinations generated a total of 3,242 polymorphic deoxyribonucleic acid (DNA) fragments in the P. stachyoides population with a percentage of polymorphic bands (PPB) ranging from 39.3 to 65.7% and 2,780 for the M. zahlbruckneri population with a PPB of 18.8 to 64.6%. Population differentiation (Fst) of AFLP loci between subpopulations of P. stachyoides was low (0.043) across populations. Analysis of molecular variance of P. stachyoides showed that 4% of the observed genetic differentiation occurred between populations in different kīpuka and 96% when individuals were pooled from all kīpuka. Moderate genetic diversity was detected within the M. zahlbruckneri population. Bayesian and multivariate analyses both classified the P. stachyoides and M. zahlbruckneri populations into genetic groups with considerable sub-structuring detected in the P. stachyoides population. The proportion of genetic differentiation among populations explained by geographical distance was estimated by Mantel tests. No spatial correlation was found between genetic and geographic distances in both populations. Finally, a moderate but significant gene flow that could be attributed to insect or bird-mediated dispersal of pollen across the different kīpuka was observed. The results of this study highlight the utility of a multi-allelic DNA-based marker in screening a large number of polymorphic loci in small and closely related endangered populations and revealed the presence of genetically unique groups of individuals in both M. zahlbruckneri and P. stachyoides populations. Based on these findings

  3. REGARDING "TRAGIC ECONOMIC OPTIMUM" FROM HOLISTIC+ PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Constantin Popescu

    2010-12-01

    Full Text Available Communication aims to discuss the new scientific vision of "the entire integrated" as it follows the recent achievements of quantum physics, psychology and biology. From this perspective, economy is seen as a living organism, part of the social organism and together with de bright ecology. The optimum of the economy as a living organism is based on dynamic compatibilities with all common living requirements. The evolution of economic life is organically linked to the unavoidable circumstances contained in the form of V. Frankl ‘s tragic triad consisting of: pain, guilt and death. In interaction with the holistic triad circumscribed by limitations, uncertainties and open interdependencies, the tragic economic optimum (TEO is formed. It can be understood as that state of economic life in which freedom of choice of scarce resources under uncertainty has in the compatibility of rationality and hope the development criteria of MEANING. TEO means to say YES to economic life even in conditions of resource limitations, bankruptcies and unemployment, negative externalities, stress, etc. By respiritualization of responsibility using scientific knowledge. TEO - involves multicriteria modeling of economic life by integrating human demands, community, environmental, spiritual and business development in the assessment predicting human GDP as a variable wave aggregate.

  4. Optimum body size of Holstein replacement heifers.

    Science.gov (United States)

    Hoffman, P C

    1997-03-01

    Criteria that define optimum body size of replacement heifers are required by commercial dairy producers to evaluate replacement heifer management programs. Historically recommended body size criteria have been based on live BW measurements. Numerous research studies have observed a positive relationship between BW at first calving and first lactation milk yield, which has served as the impetus for using live BW to define body size of replacement heifers. Live BW is, however, not the only available measurement to define body size. Skeletal measurements such as wither height, length, and pelvic area have been demonstrated to be related to first lactation performance and (or) dystocia. Live BW measurements also do not define differences in body composition. Differences in body composition of replacement heifers at first calving are also related to key performance variables. An updated research data base is available for the modern Holstein genotype to incorporate measures of skeletal growth and body composition with BW when defining body size. These research projects also lend insight into the relative importance of measurements that define body size of replacement heifers. Incorporation of these measurements from current research into present BW recommendations should aid commercial dairy producers to better define replacement heifer growth and management practices. This article proposes enhancements in defining optimum body size and growth characteristics of Holstein replacement heifers.

  5. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

    OpenAIRE

    Collier, Catherine J.; Ow, Yan X.; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L.; O'Brien, Katherine R.; Hrebien, Victoria; Adams, Matthew P.

    2017-01-01

    Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri). To obtain whole plant net production...

  6. Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants

    NARCIS (Netherlands)

    Araujo, W.L.; Marcon, J.; jr. Maccheroni, W.; Elsas, van J.D.; Vuurde, van J.W.L.; Azevedo, de J.L.

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as

  7. The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth

    Science.gov (United States)

    Kevin Ford; Joshua H. Ness; Judith L. Bronstein; William F. Morris

    2015-01-01

    The impact of mutualists on a partner’s demography depends on how they affect the partner’s multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and...

  8. Adaptive Transgenerational Plasticity in Plants: Case Studies, Mechanisms, and Implications for Natural Populations

    OpenAIRE

    Herman, Jacob J.; Sultan, Sonia E.

    2011-01-01

    Plants respond to environmental conditions not only by plastic changes to their own development and physiology, but also by altering the phenotypes expressed by their offspring. This transgenerational plasticity was initially considered to entail only negative effects of stressful parental environments, such as production of smaller seeds by resource- or temperature-stressed parent plants, and was therefore viewed as environmental noise. Recent evolutionary ecology studies have shown that in ...

  9. Possible effects of cultivated plants in the development of allergy in population of Sindh, Pakistan

    International Nuclear Information System (INIS)

    Waqar, M.A.; Khan, M.; Hasnain, S.M.

    2010-01-01

    Among the various biological particles, pollen grains and fingal spores stand as the two major factors that can cause asthma and allergic rhinitis. Pollen grains can be released by the domestic plants cultivated in and around as omamentals, on road verges and parklands etc. However. those plants are considered allergenic which are wind pollinated, called anemophilous, and very less attention is paid pollen sensitivity of cultivated plants. The purpose of this publication is to explain the types of flowering plants cultivated in Sindh, their flowering periods and the possibility of their pollen grains to induce IgE mediated hypersensitive reaction in people living in tile selected geographical region. In this survey. we have taken into consideration 60 species of plants that are being cultivated in tile province of Sindh. These species are divided into two major groups: the first group includes allergenic pollen producing species. while the second group included 38 species that are known to be non-allergenic. Our results show that most of the abundantly cultivated plants may be considered as secondary potential allergens and/or occupational or cross-reacting allergens. (author)

  10. Two disjunct Pleistocene populations and anisotropic postglacial expansion shaped the current genetic structure of the relict plant Amborella trichopoda.

    Directory of Open Access Journals (Sweden)

    Rémi Tournebize

    Full Text Available Past climate fluctuations shaped the population dynamics of organisms in space and time, and have impacted their present intra-specific genetic structure. Demo-genetic modelling allows inferring the way past demographic and migration dynamics have determined this structure. Amborella trichopoda is an emblematic relict plant endemic to New Caledonia, widely distributed in the understory of non-ultramafic rainforests. We assessed the influence of the last glacial climates on the demographic history and the paleo-distribution of 12 Amborella populations covering the whole current distribution. We performed coalescent genetic modelling of these dynamics, based on both whole-genome resequencing and microsatellite genotyping data. We found that the two main genetic groups of Amborella were shaped by the divergence of two ancestral populations during the last glacial maximum. From 12,800 years BP, the South ancestral population has expanded 6.3-fold while the size of the North population has remained stable. Recent asymmetric gene flow between the groups further contributed to the phylogeographical pattern. Spatially explicit coalescent modelling allowed us to estimate the location of ancestral populations with good accuracy (< 22 km and provided indications regarding the mid-elevation pathways that facilitated post-glacial expansion.

  11. A geoprocessing model for the selection of populations most affected by diffuse industrial contamination: the case of oil refinery plants

    Directory of Open Access Journals (Sweden)

    Roberto Pasetto

    2013-03-01

    Full Text Available INTRODUCTION. A method to select populations living in areas affected by diffuse environmental contamination is presented, with particular regard to oil refineries, in the Italian context. The reasons to use municipality instead of census tract populations for environment and health small-area studies of contaminated sites are discussed. METHODS. Populations most affected by diffuse environmental contamination are identified through a geoprocessing model. Data from the national census 2001 were used to estimate census tract level populations. A geodatabase was developed using the municipality and census tract layers provided by the Italian National Bureau of Statistics (ISTAT. The orthophotos of the Italian territory - year 2006 - available on the geographic information systems (GIS of the National Cartographic Portal, were considered. The area within 2 km from the plant border was used as an operational definition to identify the area at major contamination. RESULTS. The geoprocessing model architecture is presented. The results of its application to the selection of municipality populations in a case study are shown. CONCLUSIONS. The application of the proposed geoprocessing model, the availability of long time series of mortality and morbidity data, and a quali-quantitative estimate of contamination over time, could allow an appraisal of the health status of populations affected by oil refinery emissions.

  12. Effect of Varieties and Plant Population Densities on Dry Matter Production, Radiation Interception and Radiation Energy Conversion in Peanut

    Directory of Open Access Journals (Sweden)

    agus suprapto

    2012-05-01

    Full Text Available The solar radiation is one of the major criteria to obtaining advantages on peanuts (Arachishypogaea L.. Although various combinations of crops have been reported, but variety association and plant population densities (PPD during the periodically stage of growth on peanuts have yet to be analyzed. Dry matter production (DM, radiation energy interception, and radiation energy conversions were monitored over the growth period of two varieties of peanut. An experiment was conducted in Jambegede Research Farm, Indonesian Legume and Tuber Crops Research Institute, Malang, East Java, Indonesia, from July until October 2011. The experiment was arranged in a Split Plot Design with three replications. Peanut varieties, as the main plot consisted of two treatments: Kelinci andKancil variety. In addition, five PPD variations as sub plot consisted of 8.1, 11.1, 16.0, 25.0 and 44.4 plant m-2 were arranged in a square spacing. The results showed that DM production from high PPD increased gradually to lower PPD in all varieties. Interception efficiency (IE increased in all varieties from early sowing. A plant population density of 25.0 m-2 and 44.4 plants m-2 intercepted more radiation over 11.1 or 16.0 plants m-2. Conversion efficiency of radiation energy (CE to total dry matter production on Kelinci variety (1.52% indicated a slight higher percentage than on Kancil variety (1.41%. Moreover, the CE and IE values indicated a decrease as the PPD increased on maximum DM.

  13. Influence of Multiple Infection and Relatedness on Virulence: Disease Dynamics in an Experimental Plant Population and Its Castrating Parasite

    Science.gov (United States)

    Buono, Lorenza; López-Villavicencio, Manuela; Shykoff, Jacqui A.; Snirc, Alodie; Giraud, Tatiana

    2014-01-01

    The level of parasite virulence, i.e., the decrease in host's fitness due to a pathogen, is expected to depend on several parameters, such as the type of the disease (e.g., castrating or host-killing) and the prevalence of multiple infections. Although these parameters have been extensively studied theoretically, few empirical data are available to validate theoretical predictions. Using the anther smut castrating disease on Silene latifolia caused by Microbotryum lychnidis-dioicae, we studied the dynamics of multiple infections and of different components of virulence (host death, non-recovery and percentage of castrated stems) during the entire lifespan of the host in an experimental population. We monitored the number of fungal genotypes within plants and their relatedness across five years, using microsatellite markers, as well as the rates of recovery and host death in the population. The mean relatedness among genotypes within plants remained at a high level throughout the entire host lifespan despite the dynamics of the disease, with recurrent new infections. Recovery was lower for plants with multiple infections compared to plants infected by a single genotype. As expected for castrating parasites, M. lychnidis-dioicae did not increase host mortality. Mortality varied across years but was generally lower for plants that had been diseased the preceding year. This is one of the few studies to have empirically verified theoretical expectations for castrating parasites, and to show particularly i) that castrated hosts live longer, suggesting that parasites can redirect resources normally used in reproduction to increase host lifespan, lengthening their transmission phase, and ii) that multiple infections increase virulence, here in terms of non-recovery and host castration. PMID:24892951

  14. The Impact of Different Habitat Conditions on the Variability of Wild Populations of a Medicinal Plant Betonica officinalis L.

    Directory of Open Access Journals (Sweden)

    Kinga Kostrakiewicz-Gierałt

    2015-06-01

    Full Text Available Plants are important source of beneficial bioactive compounds which may find various applications as functional ingredients, such as components of food supplements, cosmetics, and pharmaceuticals. One such medicinal plant is Betonica officinalis, populations of which were investigated in 2012‒13. The studies were conducted in patches of Molinietum caeruleae dominated by: small meadow taxa (patch I; the shrub willow Salix repens ssp. rosmarinifolia (patch II; large tussock grasses Deschampsia caespitosa and Molinia caerulaea (patch III; tall-growing macroforbs Filipendula ulmaria and Solidago canadensis (patch IV. Over successive patches, the average height of plant cover increased, as did soil moisture, while light availability at ground level decreased. Much greater abundance and density of the Betonica officinalis population were found in patches I, III and IV, while lower values for these parameters were noted in patch II. Individuals in pre-reproductive stages were absent during whole study period in all study plots, vegetative ramet clusters were observed in plots situated in patches I and III in the first year of observations, while only generative ramet clusters occurred in plots set in patches II and IV. The number of rosettes per ramet cluster, number and dimensions of rosette leaves, height of flowering stems, number of cauline leaves, length of inflorescences, as well as number and length of flowers increased gradually over successive patches, whereas the number of generative stems per ramet cluster did not differ remarkably among populations. On the basis of the performed studies it might be concluded that the condition of populations deteriorated from patches overgrown by large-tussock grasses and characterized by considerable share of native and alien tall-growing macroforbs, via patch dominated by small meadow taxa, to patch prevailed by shrub willows.

  15. Design chart of optimum current leads

    International Nuclear Information System (INIS)

    Ishibashi, K.; Katase, A.; Maechata, K.

    1986-01-01

    The heat flow through current leads is one of major heat losses in a superconducting magnet system. To reduce the heat flow, current leads have been optimized in a complex way by varying such quantities as conductor length, cross-sectional area, heat transfer coefficient and cooling perimeter. Therefore, this study is made to simplify the design procedure, and to explain the general characteristics of the current leads. A new combined parameter which takes turbulent flow into account is introduced in the present work to enable us to draw a useful design chart. This chart gives, to a wide variety of current leads, detailed information about the optimum design-viz. geometric dimensions, heat flow into liquid helium, and pressure drop of the cooling gas. Change of the cross-sectional area along the conductor may improve the current lead performance. The effects of this area change are examined in detail

  16. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

  17. Optimum utilisation of the uranium resource

    International Nuclear Information System (INIS)

    Ion, S. E.; Wilson, P.D.

    1998-01-01

    The nuclear industry faces many challenges, notably to maximise safety, secure an adequate energy supply, manage wastes satisfactorily and achieve political acceptability. One way forward is to optimise together the various interdependent stages of the fuel cycle - the now familiar 'holistic approach'. Many of the issues will demand large R and D expenditure, most effectively met through international collaboration. Sustainable development requires optimum utilisation of energy potential, to which the most accessible key is recycling uranium and the plutonium bred from it. Realising anything like this full potential requires fast-neutron reactors, and therefore BNFL continues to sustain the UK involvement in their international development. Meanwhile, current R and D programmes must aim to make the nuclear option more competitive against fossil resources, while maintaining and developing the necessary skills for more advanced technologies The paper outlines the strategies being pursued and highlights BNFL 's programmes. (author)

  18. The demography of climate-driven and density-regulated population dynamics in a perennial plant

    DEFF Research Database (Denmark)

    Dahlgren, Johan; Bengstsson, Karin; Ehrlén, Johan

    2016-01-01

    Identifying the internal and external drivers of population dynamics is a key objective in ecology, currently accentuated by the need to forecast the effects of climate change on species distributions and abundances. The interplay between environmental and density effects is one particularly...... important aspect of such forecasts. We examined the simultaneous impact of climate and intraspecific density on vital rates of the dwarf shrub Fumana procumbens over 20 yr, using generalized additive mixed models. We then analyzed effects on population dynamics using integral projection models...... to be driven solely by the environment can overestimate extinction risks if there is density dependence. We conclude that density regulation can dampen effects of climate change on Fumana population size, and discuss the need to quantify density dependence in predictions of population responses...

  19. Possible accidents in nuclear power plants and their effect on the population

    International Nuclear Information System (INIS)

    Loester, W.

    1981-01-01

    Besides giving a classification of accidents (disturbance, maximum accident considered, uncontrollable superaccident), the paper assesses the activities released, contamination values, dose-limits for first-aid ponnel and for the radiation exposure of the population. (DG) [de

  20. Epigenetic population differentiation in field- and common garden-grown Scabiosa columbaria plants

    NARCIS (Netherlands)

    Groot, Maartje P; Wagemaker, Niels CAM; Ouborg, N Joop; Verhoeven, Koen J F; Vergeer, Philippine

    Populations often differ in phenotype and these differences can be caused by adaptation by natural selection, random neutral processes, and environmental responses. The most straightforward way to divide mechanisms that influence phenotypic variation is heritable variation and environmental-induced

  1. Molecular taxonomic analysis of the plant associations of adult pollen beetles (Nitidulidae: Meligethinae), and the population structure of Brassicogethes aeneus.

    Science.gov (United States)

    Ouvrard, Pierre; Hicks, Damien M; Mouland, Molly; Nicholls, James A; Baldock, Katherine C R; Goddard, Mark A; Kunin, William E; Potts, Simon G; Thieme, Thomas; Veromann, Eve; Stone, Graham N

    2016-12-01

    Pollen beetles (Nitidulidae: Meligethinae) are among the most abundant flower-visiting insects in Europe. While some species damage millions of hectares of crops annually, the biology of many species is little known. We assessed the utility of a 797 base pair fragment of the cytochrome oxidase 1 gene to resolve molecular operational taxonomic units (MOTUs) in 750 adult pollen beetles sampled from flowers of 63 plant species sampled across the UK and continental Europe. We used the same locus to analyse region-scale patterns in population structure and demography in an economically important pest, Brassicogethes aeneus. We identified 44 Meligethinae at ∼2% divergence, 35 of which contained published sequences. A few specimens could not be identified because the MOTUs containing them included published sequences for multiple Linnaean species, suggesting either retention of ancestral haplotype polymorphism or identification errors in published sequences. Over 90% of UK specimens were identifiable as B. aeneus. Plant associations of adult B. aeneus were found to be far wider taxonomically than for their larvae. UK B. aeneus populations showed contrasting affiliations between the north (most similar to Scandinavia and the Baltic) and south (most similar to western continental Europe), with strong signatures of population growth in the south.

  2. Ecological systems as computer networks: Long distance sea dispersal as a communication medium between island plant populations.

    Science.gov (United States)

    Sanaa, Adnen; Ben Abid, Samir; Boulila, Abdennacer; Messaoud, Chokri; Boussaid, Mohamed; Ben Fadhel, Najeh

    2016-06-01

    Ecological systems are known to exchange genetic material through animal species migration and seed dispersal for plants. Isolated plant populations have developed long distance dispersal as a means of propagation which rely on meteorological such as anemochory and hydrochory for coast, island and river bank dwelling species. Long distance dispersal by water, in particular, in the case of water current bound islands, calls for the analogy with computer networks, where each island and nearby mainland site plays the role of a network node, the water currents play the role of a transmission channel, and water borne seeds as data packets. In this paper we explore this analogy to model long distance dispersal of seeds among island and mainland populations, when traversed with water currents, in order to model and predict their future genetic diversity. The case of Pancratium maritimum L. populations in Tunisia is used as a proof of concept, where their genetic diversity is extrapolated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Life history strategies and biomass allocation : the population dynamics of perennial plants in a regional perspective

    NARCIS (Netherlands)

    Jongejans, E.

    2004-01-01

    This study aims to contribute to the knowledge of how plants respond to adverse influences of intensified land use. In particular, attention was paid to the ways in which life history strategies change in order to buffer environmental variation, and which important parts of the life cycle are

  4. Are native songbird populations affected by non-native plant invasion?

    Science.gov (United States)

    Amanda M. Conover; Christopher K. Williams; Vincent. D' Amico

    2011-01-01

    Development into forested areas is occurring rapidly across the United States, and many of the remnant forests within suburban landscapes are being fragmented into smaller patches, impacting the quality of this habitat for avian species. An ecological effect linked to forest fragmentation is the invasion of non-native plants into the ecosystem.

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

    Science.gov (United States)

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

  6. Competition between Plant-Populations with Different Rooting Depths. 3. Field Experiments

    NARCIS (Netherlands)

    Berendse, F.

    1982-01-01

    The model proposed in the first paper in this series predicts that in mixtures of plant species with different rooting depths there will be an inverse correlation between the relative crowding coefficient of the deep rooting species with respect to the shallow rooting one and the frequency of the

  7. Effects of biological control agents and exotic plant invasion on deer mouse populations

    Science.gov (United States)

    Yvette K. Ortega; Dean E. Pearson; Kevin S. McKelvey

    2004-01-01

    Exotic insects are commonly introduced as biological control agents to reduce densities of invasive exotic plants. Although current biocontrol programs for weeds take precautions to minimize ecological risks, little attention is paid to the potential nontarget effects of introduced food subsidies on native consumers. Previous research demonstrated that two gall flies (...

  8. Optimum distribution between autumn-applied and spring-applied nitrogen in seed production of tall fescue (Festuca arundinacea Schreb.)

    DEFF Research Database (Denmark)

    Gislum, René; Deleuran, Lise Christina; Kristensen, Kristian

    2012-01-01

    The effect of different autumn and spring nitrogen (N) application rates on plant establishment, plant development, and seed yield were tested in a field experiment using tall fescue (Festuca arundinacea Schreb.). Results clearly showed that the optimum distribution of N between autumn and spring...... to achieve the highest seed yield and economical benefit was dependent on the choice of cover crops and location. The economically optimum N application rate was in the range from 44 to 73 kg ha−1 in autumn and 94 to 157 kg ha−1 in spring. The results are discussed in relation to Danish N regulations...... and plant establishment and development....

  9. On flavonoid accumulation in different plant parts: Variation patterns among individuals and populations in the shore campion (Silene littorea.

    Directory of Open Access Journals (Sweden)

    Jose Carlos Del Valle

    2015-10-01

    Full Text Available The presence of anthocyanins in flowers and fruits is frequently attributed to attracting pollinators and dispersers. In vegetative organs, anthocyanins and other non-pigmented flavonoids such as flavones and flavonols may serve protective functions against UV radiation, cold, heat, drought, salinity, pathogens and herbivores; thus, these compounds are usually produced as a plastic response to such stressors. Although the independent accumulation of anthocyanins in reproductive and vegetative tissues is commonly postulated due to differential regulation, the accumulation of flavonoids within and among populations has never been thoroughly compared. Here, we investigated the shore campion (Silene littorea, Caryophyllaceae which exhibits variation in anthocyanin accumulation in its floral and vegetative tissues. We examined the in-situ accumulation of flavonoids in floral (petals and calyxes and vegetative organs (leaves from 18 populations representing the species’ geographic distribution. Each organ exhibited considerable variability in the content of anthocyanins and other flavonoids both within and among populations. In all organs, anthocyanin and other flavonoids were correlated. At the plant level, the flavonoid content in petals, calyxes and leaves was not correlated in most of the populations. However, at the population level, the mean amount of anthocyanins in all organs was positively correlated, which suggests that the variable environmental conditions of populations may play a role in anthocyanin accumulation. These results are unexpected because the anthocyanins are usually constitutive in petals, yet contingent to environmental conditions in calyxes and leaves. Anthocyanin variation in petals may influence pollinator attraction and subsequent plant reproduction, yet the amount of anthocyanins may be a direct response to environmental factors. In populations on the west coast, a general pattern of increasing accumulation of

  10. Selection for high oridonin yield in the Chinese medicinal plant Isodon (Lamiaceae using a combined phylogenetics and population genetics approach.

    Directory of Open Access Journals (Sweden)

    Eric S J Harris

    Full Text Available Oridonin is a diterpenoid with anti-cancer activity that occurs in the Chinese medicinal plant Isodon rubescens and some related species. While the bioactivity of oridonin has been well studied, the extent of natural variation in the production of this compound is poorly known. This study characterizes natural variation in oridonin production in order to guide selection of populations of Isodon with highest oridonin yield. Different populations of I. rubescens and related species were collected in China, and their offspring were grown in a greenhouse. Samples were examined for oridonin content, genotyped using 11 microsatellites, and representatives were sequenced for three phylogenetic markers (ITS, rps16, trnL-trnF. Oridonin production was mapped on a molecular phylogeny of the genus Isodon using samples from each population as well as previously published Genbank sequences. Oridonin has been reported in 12 out of 74 species of Isodon examined for diterpenoids, and the phylogeny indicates that oridonin production has arisen at least three times in the genus. Oridonin production was surprisingly consistent between wild-collected parents and greenhouse-grown offspring, despite evidence of gene flow between oridonin-producing and non-producing populations of Isodon. Additionally, microsatellite genetic distance between individuals was significantly correlated with chemical distance in both parents and offspring. Neither heritability nor correlation with genetic distance were significant when the comparison was restricted to only populations of I. rubescens, but this result should be corroborated using additional samples. Based on these results, future screening of Isodon populations for oridonin yield should initially prioritize a broad survey of all species known to produce oridonin, rather than focusing on multiple populations of one species, such as I. rubescens. Of the samples examined here, I. rubescens or I. japonicus from Henan province

  11. Optimum Water Chemistry in radiation field buildup control

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien, C. [Vallecitos Nuclear Center, Pleasanton, CA (United States)

    1995-03-01

    Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of low exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.

  12. Effect of Plant Density and Land Race on the Growth and Yield of ...

    African Journals Online (AJOL)

    Field study was conducted at National Root Crops Research Institute out station Nyanya Research farm located at Zhewun Jidna Nasarawa State during 2007 and 2008 cropping seasons. The aim was to determine the effect of optimum plant population Density of sweet potato land races under improved management ...

  13. Great genetic differentiation among populations of Meconopsis integrifolia and its implication for plant speciation in the Qinghai-Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Fu-Sheng Yang

    Full Text Available The complex tectonic events and climatic oscillations in the Qinghai-Tibetan Plateau (QTP, the largest and highest plateau in the world, are thought to have had great effects on the evolutionary history of the native plants. Of great interest is to investigate plant population genetic divergence in the QTP and its correlation with the geologic and climatic changes. We conducted a range-wide phylogeographical analysis of M. integrifolia based on the chloroplast DNA (cpDNA trnL-trnF and trnfM-trnS regions, and defined 26 haplotypes that were phylogenetically divided into six clades dated to the late Tertiary. The six clades correspond, respectively, to highly differentiated population groups that do not overlap in geographic distribution, implying that the mountain ranges acting as corridors or barriers greatly affected the evolutionary history of the QTP plants. The older clade of M. integrifolia only occurs in the southwest of the species' range, whereas the distributions of younger clades extend northeastward in the eastern QTP, suggesting that climatic divergence resulting from the uplift of the QTP triggered the initial divergence of M. integrifolia native to the plateau. Also, the nrDNA ITS region was used to clarify the unexpected phylogenetic relationships of cpDNA haplotypes between M. integrifolia and M. betonicifolia. The topological incongruence between the two phylogenies suggests an ancestral hybridization between the two species. Our study indicates that geographic isolation and hybridization are two important mechanisms responsible for the population differentiation and speciation of Meconopsis, a species-rich genus with complex polyploids.

  14. [GENETIC VARIABILITY OF MATERNAL PLANTS AND SEED EMBRYOS OF KOCH PINE POPULATIONS (PINUS KOCHIANA KLOTZSCH EX KOCH) IN CRIMEA].

    Science.gov (United States)

    Korshykov, I I; Kalafat, L O; Vynogradova, O M; Podgornyi, D Y

    2016-01-01

    Comparative studies of genetic variability were undertaken for 12 allozyme loci selections of trees and embryos of seed, and also for the crossing systems in five populations of Koch pine of (Pinus kochiana Klotzsch ex Koch) in Crimea. It was shown that in seed embryos the allelic variety peculiar to the maternal plants was restored, however the level of the available (H₀) heterozygosity was considerably lower, 0.286 and 0.189 respectively. For the embryos unlike the trees, in the majority of the analyzed loci the considerable divergence was specific in the actual distribution of genotypes from the theoretically expected according to Hardy- Weinberg law. The proportion of cross pollination at the unilocal (t(s)) estimation varied from 0.384 to 0.673 in the populations, while at the multilocal ones (t(m)) it was 0.639-0.841.

  15. Population dose commitments due to radioactive releases from nuclear power plant sites in 1975

    International Nuclear Information System (INIS)

    Baker, D.A.; Soldat, J.K.; Watson, E.C.

    1977-10-01

    Population radiation dose commitments were estimated from reported radionuclide releases from commercial power reactors operating during 1975. Fifty-year dose commitments from one year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teenager and adult) residing between 2 and 80 km from each site. Results are given in the form of tables giving the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within the 2 to 80-km region around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 750 person-rem to a low of 0.008 person-rem with an arithmetic mean of 34 person-rem

  16. Health state of population in the locality of the Mochovce nuclear power plant after four years of operation

    International Nuclear Information System (INIS)

    Letkovicova, M.; Letkovicova, H.; Letkovic, M.

    2002-01-01

    work demand and thus also higher poverty and worse health state. Probably already in the consequence of construction of nuclear power plant number of work opportunities came into the region, situation is still getting better with putting of plant into the operation. Authors consider it as indirect positive (and maybe slightly unexpected) influence. The health state of population can be objectively evaluated in the Slovak Republic. Authors have enough of serious sources for it. Not by the most detailed monitoring of big team of authors from different field can be found out unfavourable health state consequences on population living in the vicinity of Mochovce NPP during its periodical operation. (authors)

  17. A below-ground herbivore shapes root defensive chemistry in natural plant populations

    OpenAIRE

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Th?o; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root ...

  18. An innovative procedure of genome-wide association analysis fits studies on germplasm population and plant breeding.

    Science.gov (United States)

    He, Jianbo; Meng, Shan; Zhao, Tuanjie; Xing, Guangnan; Yang, Shouping; Li, Yan; Guan, Rongzhan; Lu, Jiangjie; Wang, Yufeng; Xia, Qiuju; Yang, Bing; Gai, Junyi

    2017-11-01

    The innovative RTM-GWAS procedure provides a relatively thorough detection of QTL and their multiple alleles for germplasm population characterization, gene network identification, and genomic selection strategy innovation in plant breeding. The previous genome-wide association studies (GWAS) have been concentrated on finding a handful of major quantitative trait loci (QTL), but plant breeders are interested in revealing the whole-genome QTL-allele constitution in breeding materials/germplasm (in which tremendous historical allelic variation has been accumulated) for genome-wide improvement. To match this requirement, two innovations were suggested for GWAS: first grouping tightly linked sequential SNPs into linkage disequilibrium blocks (SNPLDBs) to form markers with multi-allelic haplotypes, and second utilizing two-stage association analysis for QTL identification, where the markers were preselected by single-locus model followed by multi-locus multi-allele model stepwise regression. Our proposed GWAS procedure is characterized as a novel restricted two-stage multi-locus multi-allele GWAS (RTM-GWAS, https://github.com/njau-sri/rtm-gwas ). The Chinese soybean germplasm population (CSGP) composed of 1024 accessions with 36,952 SNPLDBs (generated from 145,558 SNPs, with reduced linkage disequilibrium decay distance) was used to demonstrate the power and efficiency of RTM-GWAS. Using the CSGP marker information, simulation studies demonstrated that RTM-GWAS achieved the highest QTL detection power and efficiency compared with the previous procedures, especially under large sample size and high trait heritability conditions. A relatively thorough detection of QTL with their multiple alleles was achieved by RTM-GWAS compared with the linear mixed model method on 100-seed weight in CSGP. A QTL-allele matrix (402 alleles of 139 QTL × 1024 accessions) was established as a compact form of the population genetic constitution. The 100-seed weight QTL-allele matrix was

  19. Infection rates and comparative population dynamics of Peregrinus maidis (Hemiptera: Delphacidae) on corn plants with and without symptoms of maize mosaic virus (Rhabdoviridae: Nucleorhabdovirus) infection.

    Science.gov (United States)

    Higashi, C H V; Bressan, A

    2013-10-01

    We examined the population dynamics of the corn planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae) throughout a cycle of corn (Zea mays L.) production on plants with or without symptoms of maize mosaic virus (MMV) (Rhabdoviridae: Nucleorhabdovirus) infection. Our results indicate that the timing of MMV plant infection greatly influenced the planthopper's host plant colonization patterns. Corn plants that expressed symptoms of MMV infection early in the crop cycle (28 d after planting) harbored, on average, 40 and 48% fewer planthoppers than plants that expressed symptoms of MMV infection later in the crop cycle (49 d after planting) and asymptomatic plants, respectively. We also observed a change in the number of brachypterous (short-wing type) and macropterous (long-wing type) winged forms produced; plants expressing early symptoms of MMV infection harbored, on average, 41 and 47% more of the brachypterous form than plants with late infections of MMV and plants with no symptoms of MMV, respectively. Furthermore, we determined the rates of MMV-infected planthoppers relative to their wing morphology (macropterous or brachypterous) and gender. MMV infection was 5 and 12% higher in females than in males in field and greenhouse experiments, respectively; however, these differences were not significantly different. This research provides evidence that MMV similarly infects P. maidis planthoppers regardless of the gender and wing morphotype. These results also suggest that the timing of symptom development greatly affects the population dynamics of the planthopper vector, and likely has important consequences for the dynamics of the disease in the field.

  20. An Optimum Solution for Electric Power Theft

    Directory of Open Access Journals (Sweden)

    Aamir Hussain Memon

    2013-07-01

    Full Text Available Electric power theft is a problem that continues to plague power sector across the whole country. Every year, the electricity companies face the line losses at an average 20-30% and according to power ministry estimation WAPDA companies lose more than Rs. 125 billion. Significantly, it is enough to destroy the entire power sector of country. According to sources 20% losses means the masses would have to pay extra 20% in terms of electricity tariffs. In other words, the innocent consumers pay the bills of those who steal electricity. For all that, no any permanent solution for this major issue has ever been proposed. We propose an applicable and optimum solution for this impassable problem. In our research, we propose an Electric power theft solution based on three stages; Transmission stage, Distribution stage, and User stage. Without synchronization among all, the complete solution can not be achieved. The proposed solution is simulated on NI (National Instruments Circuit Design Suite Multisim v.10.0. Our research work is an implicit and a workable approach towards the Electric power theft, as for conditions in Pakistan, which is bearing the brunt of power crises already

  1. Mesh networks: an optimum solution for AMR

    Energy Technology Data Exchange (ETDEWEB)

    Mimno, G.

    2003-12-01

    Characteristics of mesh networks and the advantage of using them in automatic meter reading equipment (AMR) are discussed. Mesh networks are defined as being similar to a fishing net made of knots and links. In mesh networks the knots represent meter sites and the links are the radio paths between the meter sites and the neighbourhood concentrator. In mesh networks any knot in the communications chain can link to any other and the optimum path is calculated by the network by hopping from meter to meter until the radio message reaches a concentrator. This mesh communications architecture is said to be vastly superior to many older types of radio-based meter reading technologies; its main advantage is that it not only significantly improves the economics of fixed network deployment, but also supports time-of-use metering, remote disconnect services and advanced features, such as real-time pricing, demand response, and other efficiency measures, providing a better return on investment and reliability.

  2. Optimum harvest maturity for Leymus chinensis seed

    Directory of Open Access Journals (Sweden)

    Jixiang Lin

    2016-06-01

    Full Text Available Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT and accelerated ageing test (AAT. Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest.

  3. Designing from minimum to optimum functionality

    Science.gov (United States)

    Bannova, Olga; Bell, Larry

    2011-04-01

    This paper discusses a multifaceted strategy to link NASA Minimal Functionality Habitable Element (MFHE) requirements to a compatible growth plan; leading forward to evolutionary, deployable habitats including outpost development stages. The discussion begins by reviewing fundamental geometric features inherent in small scale, vertical and horizontal, pressurized module configuration options to characterize applicability to meet stringent MFHE constraints. A proposed scenario to incorporate a vertical core MFHE concept into an expanded architecture to provide continuity of structural form and a logical path from "minimum" to "optimum" design of a habitable module. The paper describes how habitation and logistics accommodations could be pre-integrated into a common Hab/Log Module that serves both habitation and logistics functions. This is offered as a means to reduce unnecessary redundant development costs and to avoid EVA-intensive on-site adaptation and retrofitting requirements for augmented crew capacity. An evolutionary version of the hard shell Hab/Log design would have an expandable middle section to afford larger living and working accommodations. In conclusion, the paper illustrates that a number of cargo missions referenced for NASA's 4.0.0 Lunar Campaign Scenario could be eliminated altogether to expedite progress and reduce budgets. The plan concludes with a vertical growth geometry that provides versatile and efficient site development opportunities using a combination of hard Hab/Log modules and a hybrid expandable "CLAM" (Crew Lunar Accommodations Module) element.

  4. Achieving optimum diffraction based overlay performance

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee; Coogans, Martyn; Fuchs, Andreas; Ponomarenko, Mariya; van der Schaar, Maurits; Vanoppen, Peter

    2010-03-01

    Diffraction Based Overlay (DBO) metrology has been shown to have significantly reduced Total Measurement Uncertainty (TMU) compared to Image Based Overlay (IBO), primarily due to having no measurable Tool Induced Shift (TIS). However, the advantages of having no measurable TIS can be outweighed by increased susceptibility to WIS (Wafer Induced Shift) caused by target damage, process non-uniformities and variations. The path to optimum DBO performance lies in having well characterized metrology targets, which are insensitive to process non-uniformities and variations, in combination with optimized recipes which take advantage of advanced DBO designs. In this work we examine the impact of different degrees of process non-uniformity and target damage on DBO measurement gratings and study their impact on overlay measurement accuracy and precision. Multiple wavelength and dual polarization scatterometry are used to characterize the DBO design performance over the range of process variation. In conclusion, we describe the robustness of DBO metrology to target damage and show how to exploit the measurement capability of a multiple wavelength, dual polarization scatterometry tool to ensure the required measurement accuracy for current and future technology nodes.

  5. Population genetic structure of the lettuce root aphid, Pemphigus bursarius (L.), in relation to geographic distance, gene flow and host plant usage.

    Science.gov (United States)

    Miller, N J; Birley, A J; Overall, A D J; Tatchell, G M

    2003-09-01

    Microsatellite markers were used to examine the population structure of Pemphigus bursarius, a cyclically parthenogenetic aphid. Substantial allele frequency differences were observed between populations on the primary host plant (collected shortly after sexual reproduction) separated by distances as low as 14 km. This suggested that migratory movements occur over relatively short distances in this species. However, the degree of allele frequency divergence between populations was not correlated with their geographical separation, indicating that isolation by distance was not the sole cause of spatial genetic structuring. Significant excesses of homozygotes were observed in several populations. Substantial allele frequency differences were also found between aphids on the primary host and those sampled from a secondary host plant after several parthenogenetic generations at the same location in two successive years. This could have been due to the existence of obligately parthenogenetic lineages living on the secondary host or genetically divergent populations confined to different secondary host plant species but sharing a common primary host.

  6. Recurrent Selection and Participatory Plant Breeding for Improvement of Two Organic Open-Pollinated Sweet Corn (Zea mays L. Populations

    Directory of Open Access Journals (Sweden)

    Adrienne C. Shelton

    2015-04-01

    Full Text Available Organic growers face unique challenges when raising sweet corn, and benefit from varieties that maintain high eating quality, germinate consistently, deter insect pests, and resist diseases. Genotype by environment rank changes can occur in the performance of cultivars grown on conventional and organic farms, yet few varieties have been bred specifically for organic systems. The objective of this experiment was to evaluate the changes made to open-pollinated sweet corn populations using recurrent selection and a participatory plant breeding (PPB methodology. From 2008 to 2011, four cycles of two open-pollinated (OP sweet corn populations were selected on a certified organic farm in Minnesota using a modified ear-to-row recurrent selection scheme. Selections were made in collaboration with an organic farmer, with selection criteria based on traits identified by the farmer. In 2012 and 2013, the population cycles were evaluated in a randomized complete block design in two certified organic locations in Wisconsin, with multiple replications in each environment. Significant linear trends were found among cycles of selection for quantitative and qualitative traits, suggesting the changes were due to recurrent selection and PPB methodology for these populations. However, further improvement is necessary to satisfy the requirements for a useful cultivar for organic growers.

  7. Population dose commitments due to radioactive releases from Nuclear-Power-Plant Sites in 1979

    International Nuclear Information System (INIS)

    Baker, D.A.; Peloquin, R.A.

    1982-12-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1979. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 1300 person-rem to a low of 0.0002 person-rem with an arithmetic mean of 38 person-rem. The total population dose for all sites was estimated at 1800 person-rem for the 94 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 2 x 10 - 6 mrem to a high of 0.7 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites

  8. Population dose commitments due to radioactive releases from nuclear power plant sites in 1980

    International Nuclear Information System (INIS)

    Baker, D.A.; Peloquin, R.A.

    1983-08-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1980. In addition doses derived from the shutdown reactors at the Three Mile Island site were included. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 40 person-rem to a low of 0.02 person-rem with an arithmetic mean of 4 person-rem. The total population dose for all sites was estimated at 180 person-rem for the 96 million people considered at risk

  9. Population dose commitments due to radioactive releases from nuclear-power-plant sites in 1978

    International Nuclear Information System (INIS)

    Peloquin, R.A.; Schwab, J.D.; Baker, D.A.

    1982-06-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1978. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 200 person-rem to a low of 0.0004 person-rem with an arithmetic mean of 14 person-rem. The total population dose for allsites was estimated at 660 person-rem for the 93 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 3 x 10 -6 mrem to a high of 0.08 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites

  10. Population dose commitments due to radioactive releases from nuclear power plant sites in 1981. Volume 3

    International Nuclear Information System (INIS)

    Baker, D.A.; Peloquin, R.A.

    1985-01-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1981. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teenager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways from 48 sites ranged from a high of 20 person-rem to a low of 0.008 person-rem with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 160 person-rem for the 98 million people considered at risk

  11. Variable Demographic Rates in an Invasive Plant Species: Differences Among Populations and Management Implications

    Science.gov (United States)

    Population managers are frequently faced with the challenge of selecting the most effective management strategy from a set of available strategies. In the case of classical weed biological control, this requires predicting a priori which of a group of candidate biocontrol agent species has the great...

  12. Optimum bolus wizard settings in insulin pumps in children with Type 1 diabetes

    DEFF Research Database (Denmark)

    Andersen, A J B; Ostenfeld, A; Pipper, C B

    2016-01-01

    : Optimum insulin pump settings at pump initiation depend on both insulin requirements and use of the pump. Settings need to be individualized because the standardized calculation factors are not constant for children. There is a need to develop specific age- and insulin dose-dependent calculation factors.......AIM: To evaluate current insulin pump settings in an optimally regulated paediatric population using bolus wizard. METHODS: We used a retrospective study design to analyse data from 124 children on insulin pump therapy who had optimum HbA1c levels [

  13. Climate-associated population declines reverse recovery and threaten future of an iconic high-elevation plant

    Science.gov (United States)

    Krushelnycky, Paul D.; Loope, Lloyd L.; Giambelluca, Thomas W.; Starr, Forest; Starr, Kim; Drake, Donald R.; Taylor, Andrew D.; Robichaux, Robert H.

    2013-01-01

    Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai‘i, but is a highly charismatic giant rosette plant that is viewed by 1–2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management, this iconic species has entered a period of substantial climate-associated decline. Mortality has been highest at the lower end of the distributional range, where most silverswords occur, and the strong association of annual population growth rates with patterns of precipitation suggests an increasing frequency of lethal water stress. Local climate data confirm trends toward warmer and drier conditions on the mountain, and signify a bleak outlook for silverswords if these trends continue. The silversword example foreshadows trouble for diversity in other biological hotspots, and illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses.

  14. Climate-associated population declines reverse recovery and threaten future of an iconic high-elevation plant.

    Science.gov (United States)

    Krushelnycky, Paul D; Loope, Lloyd L; Giambelluca, Thomas W; Starr, Forest; Starr, Kim; Drake, Donald R; Taylor, Andrew D; Robichaux, Robert H

    2013-03-01

    Although climate change is predicted to place mountain-top and other narrowly endemic species at severe risk of extinction, the ecological processes involved in such extinctions are still poorly resolved. In addition, much of this biodiversity loss will likely go unobserved, and therefore largely unappreciated. The Haleakalā silversword is restricted to a single volcano summit in Hawai'i, but is a highly charismatic giant rosette plant that is viewed by 1-2 million visitors annually. We link detailed local climate data to a lengthy demographic record, and combine both with a population-wide assessment of recent plant mortality and recruitment, to show that after decades of strong recovery following successful management, this iconic species has entered a period of substantial climate-associated decline. Mortality has been highest at the lower end of the distributional range, where most silverswords occur, and the strong association of annual population growth rates with patterns of precipitation suggests an increasing frequency of lethal water stress. Local climate data confirm trends toward warmer and drier conditions on the mountain, and signify a bleak outlook for silverswords if these trends continue. The silversword example foreshadows trouble for diversity in other biological hotspots, and illustrates how even well-protected and relatively abundant species may succumb to climate-induced stresses. © 2012 Blackwell Publishing Ltd.

  15. Radiation exposure of the population from 222Rn and other natural radionuclides around Mochovce nuclear power plant, Slovakia

    International Nuclear Information System (INIS)

    Bulko, Martin; Holy, Karol; Mullerova, Monika; Bohm, Radoslav; Pohronska, Zofia; Hola, Olga

    2017-01-01

    In this article, the effective dose to the population from natural sources of ionizing radiation in the vicinity of Mochovce nuclear power plant in Slovakia is presented. All major contributions to the effective dose were taken into account, including the contributions from gamma radiation of soil and rocks, cosmic radiation, and indoor and outdoor radon and thoron. On the basis of recent indoor radon measurements in Slovak cities and publicly available data about radon concentration in the soil air, a roughly linear relationship was found between these variables. Consequently, the annual effective dose from indoor radon and thoron was conservatively estimated. For the area of interest, a map of conservatively estimated potential effective doses was created. For the villages in the vicinity of Mochovce, the conservatively estimated effective dose to the population from natural sources ranged from 5.4 to 14.6 mSv, which is four orders of magnitude higher than the contribution of radioactive discharges from Mochovce nuclear power plant. (authors)

  16. An estimation of population doses from a nuclear power plant during normal operation

    International Nuclear Information System (INIS)

    Nowicki, K.

    1975-07-01

    A model is presented for estimation of the potential submersion and inhalation radiation doses to people located within a distance of 1000 km from a nuclear power plant during normal operation. The model was used to calculate doses for people living 200-1000 km from hypothetical nuclear power facility sited near the geographical centre of Denmark. Two kinds of sources are considered for this situation: - unit release of 15 isotopes of noble gases and iodines, - effluent releases from two types of 1000 MWe Light Water Power Reactors: PWR and BWR. Parameter variations were made and analyzed in order to obtain a better understanding of the mechanisms of the model. (author)

  17. Mapping the Centimeter-Scale Spatial Variability of PAHs and Microbial Populations in the Rhizosphere of Two Plants.

    Directory of Open Access Journals (Sweden)

    Amélia Bourceret

    Full Text Available Rhizoremediation uses root development and exudation to favor microbial activity. Thus it can enhance polycyclic aromatic hydrocarbon (PAH biodegradation in contaminated soils. Spatial heterogeneity of rhizosphere processes, mainly linked to the root development stage and to the plant species, could explain the contrasted rhizoremediation efficiency levels reported in the literature. Aim of the present study was to test if spatial variability in the whole plant rhizosphere, explored at the centimetre-scale, would influence the abundance of microorganisms (bacteria and fungi, and the abundance and activity of PAH-degrading bacteria, leading to spatial variability in PAH concentrations. Two contrasted rhizospheres were compared after 37 days of alfalfa or ryegrass growth in independent rhizotron devices. Almost all spiked PAHs were degraded, and the density of the PAH-degrading bacterial populations increased in both rhizospheres during the incubation period. Mapping of multiparametric data through geostatistical estimation (kriging revealed that although root biomass was spatially structured, PAH distribution was not. However a greater variability of the PAH content was observed in the rhizosphere of alfalfa. Yet, in the ryegrass-planted rhizotron, the Gram-positive PAH-degraders followed a reverse depth gradient to root biomass, but were positively correlated to the soil pH and carbohydrate concentrations. The two rhizospheres structured the microbial community differently: a fungus-to-bacterium depth gradient similar to the root biomass gradient only formed in the alfalfa rhizotron.

  18. The impact of feedstock cost on technology selection and optimum size

    International Nuclear Information System (INIS)

    Cameron, Jay B.; Kumar, Amit; Flynn, Peter C.

    2007-01-01

    Development of biomass projects at optimum size and technology enhances the role that biomass can make in mitigating greenhouse gas. Optimum sized plants can be built when biomass resources are sufficient to meet feedstock demand; examples include wood and forest harvest residues from extensive forests, and grain straw and corn stover from large agricultural regions. The impact of feedstock cost on technology selection is evaluated by comparing the cost of power from the gasification and direct combustion of boreal forest wood chips. Optimum size is a function of plant cost and the distance variable cost (DVC, $ dry tonne -1 km -1 ) of the biomass fuel; distance fixed costs (DFC, $ dry tonne -1 ) such as acquisition, harvesting, loading and unloading do not impact optimum size. At low values of DVC and DFC, as occur with wood chips sourced from the boreal forest, direct combustion has a lower power cost than gasification. At higher values of DVC and DFC, gasification has a lower power cost than direct combustion. This crossover in most economic technology will always arise when a more efficient technology with a higher capital cost per unit of output is compared to a less efficient technology with a lower capital cost per unit of output. In such cases technology selection cannot be separated from an analysis of feedstock cost

  19. Genetic consequences of radioactive pollution of the environment caused by the chernobyl accident for plants populations

    International Nuclear Information System (INIS)

    Shevchenko, V.A.; Abramov, V.I.; Kal'chenko, V.A.; Fedotov, I.S.

    1996-01-01

    Populations of Arabidopsis thaliana Heynh, and Sylvestris L., growing within 30 km of Chernobyl and Bransk region have been analyzed for the frequency of embryonic lethal mutations on arabidopsis and frequency of chlorophill mutations and chromosome aberrations by pine. On pine also have been analyzed rate of mutations at enzyme loci in endosperms of seeds. Dose dependence of the value genetic damage on level of radioactive pollution was observed. Refs. 30, figs. 4, tabs. 6

  20. Fish population genetic structure shaped by hydroelectric power plants in the upper Rhine catchment.

    Science.gov (United States)

    Gouskov, Alexandre; Reyes, Marta; Wirthner-Bitterlin, Lisa; Vorburger, Christoph

    2016-02-01

    The Rhine catchment in Switzerland has been transformed by a chain of hydroelectric power stations. We addressed the impact of fragmentation on the genetic structure of fish populations by focusing on the European chub (Squalius cephalus). This fish species is not stocked and copes well with altered habitats, enabling an assessment of the effects of fragmentation per se. Using microsatellites, we genotyped 2133 chub from 47 sites within the catchment fragmented by 37 hydroelectric power stations, two weirs and the Rhine Falls. The shallow genetic population structure reflected drainage topology and was affected significantly by barriers to migration. The effect of power stations equipped with fishpasses on genetic differentiation was detectable, albeit weaker than that of man-made barriers without fishpasses. The Rhine Falls as the only long-standing natural obstacle (formed 14 000 to 17 000 years ago) also had a strong effect. Man-made barriers also exacerbated the upstream decrease in allelic diversity in the catchment, particularly when lacking fishpasses. Thus, existing fishpasses do have the desired effect of mitigating fragmentation, but barriers still reduce population connectivity in a fish that traverses fishpasses better than many other species. Less mobile species are likely to be affected more severely.

  1. Population dose commitments due to radioactive releases from nuclear power plant sites in 1987

    International Nuclear Information System (INIS)

    Baker, D.A.

    1990-08-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1987. Fifty-year dose commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 70 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for reach of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The site average individual dose commitment from all pathways ranged from a low of 2 x 10 -6 mrem to a high of 0.009 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. However, licensee calculation of doses to the maximally exposed individual at some sites indicated values of up to approximately 100 times average individual doses (on the order of a few millirem per year). 2 refs., 2 figs., 7 tabs

  2. Phenotypic plasticity despite source-sink population dynamics in a long-lived perennial plant.

    Science.gov (United States)

    Anderson, Jill T; Sparks, Jed P; Geber, Monica A

    2010-11-01

    • Species that exhibit adaptive plasticity alter their phenotypes in response to environmental conditions, thereby maximizing fitness in heterogeneous landscapes. However, under demographic source-sink dynamics, selection should favor traits that enhance fitness in the source habitat at the expense of fitness in the marginal habitat. Consistent with source-sink dynamics, the perennial blueberry, Vaccinium elliottii (Ericaceae), shows substantially higher fitness and population sizes in dry upland forests than in flood-prone bottomland forests, and asymmetrical gene flow occurs from upland populations into bottomland populations. Here, we examined whether this species expresses plasticity to these distinct environments despite source-sink dynamics. • We assessed phenotypic responses to a complex environmental gradient in the field and to water stress in the glasshouse. • Contrary to expectations, V. elliottii exhibited a high degree of plasticity in foliar and root traits (specific leaf area, carbon isotope ratios, foliar nitrogen content, root : shoot ratio, root porosity and root architecture). • We propose that plasticity can be maintained in source-sink systems if it is favored within the source habitat and/or a phylogenetic artifact that is not costly. Additionally, plasticity could be advantageous if habitat-based differences in fitness result from incipient niche expansion. Our results illuminate the importance of evaluating phenotypic traits and fitness components across heterogeneous landscapes. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  3. Determination optimum dose gamma ray for make mutation in Banana explant (Musa spp. Var cavendish)

    International Nuclear Information System (INIS)

    Goorchini, H.; Nematzadeh, Gh. A.; Majd, F.; Rahimi, M.

    2006-01-01

    Banana belongs to Musaceae family and Musa genus, categorized as a plant growing in tropical and subtropical regions. In recent years, many attempts have been made for extending the cultivation of this plant in Iran. The cultivars, which are cultivating commonly in Iran are mostly Cavendish and Grand Nain, having rather long heights (2-4 meters). This research has been carried out aiming at determining the optimum dose rate to induce mutation in the banana plant shoot-tips. For this purpose the plant shoot-tips were exposed to various doses of gamma radiation with eight treatments of 0, 10, 15, 20, 25, 35, 45 and 60 Gray. The project was directed in a completely randomized design. After the treatment, various traits such as: number of alive plants, number of leafs, plant height and wet weight have been measured. For the data analysis, SAS and MSTAT softwares have been used in order to evaluate the average values and variances of the output results for the further analysis and comparisons. The results indicate that the dose rates of 25 to 40 Gray are the optimum rate values for induction of the mutation in this plant. Also, the propit analysis shows that the dose rate of 39.8 Gray is at the point of LD50 (50% of the dead level)

  4. Variable Isotopic Compositions of Host Plant Populations Preclude Assessment of Aphid Overwintering Sites

    Directory of Open Access Journals (Sweden)

    Michael S. Crossley

    2017-12-01

    Full Text Available Soybean aphid (Aphis glycines Matsumura is a pest of soybean in the northern Midwest whose migratory patterns have been difficult to quantify. Improved knowledge of soybean aphid overwintering sites could facilitate the development of control efforts with exponential impacts on aphid densities on a regional scale. In this preliminary study, we explored the utility of variation in stable isotopes of carbon and nitrogen to distinguish soybean aphid overwintering origins. We compared variation in bulk 13C and 15N content in buckthorn (Rhamnus cathartica L. and soybean aphids in Wisconsin, among known overwintering locations in the northern Midwest. Specifically, we looked for associations between buckthorn and environmental variables that could aid in identifying overwintering habitats. We detected significant evidence of correlation between the bulk 13C and 15N signals of soybean aphids and buckthorn, despite high variability in stable isotope composition within and among buckthorn plants. Further, the 15N signal in buckthorn varied predictably with soil composition. However, lack of sufficient differentiation of geographic areas along axes of isotopic and environmental variation appears to preclude the use of carbon and nitrogen isotopic signals as effective predictors of likely aphid overwintering sites. These preliminary data suggest the need for future work that can further account for variability in 13C and 15N within/among buckthorn plants, and that explores the utility of other stable isotopes in assessing likely aphid overwintering sites.

  5. Prediction of genetic values of quantitative traits with epistatic effects in plant breeding populations.

    Science.gov (United States)

    Wang, D; Salah El-Basyoni, I; Stephen Baenziger, P; Crossa, J; Eskridge, K M; Dweikat, I

    2012-11-01

    Though epistasis has long been postulated to have a critical role in genetic regulation of important pathways as well as provide a major source of variation in the process of speciation, the importance of epistasis for genomic selection in the context of plant breeding is still being debated. In this paper, we report the results on the prediction of genetic values with epistatic effects for 280 accessions in the Nebraska Wheat Breeding Program using adaptive mixed least absolute shrinkage and selection operator (LASSO). The development of adaptive mixed LASSO, originally designed for association mapping, for the context of genomic selection is reported. The results show that adaptive mixed LASSO can be successfully applied to the prediction of genetic values while incorporating both marker main effects and epistatic effects. Especially, the prediction accuracy is substantially improved by the inclusion of two-locus epistatic effects (more than onefold in some cases as measured by cross-validation correlation coefficient), which is observed for multiple traits and planting locations. This points to significant potential in using non-additive genetic effects for genomic selection in crop breeding practices.

  6. 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

  7. Implementation of optimum solar electricity generating system

    International Nuclear Information System (INIS)

    Singh, Balbir Singh Mahinder; Karim, Samsul Ariffin A.; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep

    2014-01-01

    Under the 10 th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels

  8. Implementation of optimum solar electricity generating system

    Science.gov (United States)

    Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

    2014-10-01

    Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  9. Implementation of optimum solar electricity generating system

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Balbir Singh Mahinder, E-mail: balbir@petronas.com.my; Karim, Samsul Ariffin A., E-mail: samsul-ariffin@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Sivapalan, Subarna, E-mail: subarna-sivapalan@petronas.com.my [Department of Management and Humanities, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Najib, Nurul Syafiqah Mohd; Menon, Pradeep [Department of Electrical and Electronics Engineering, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  10. Population level analysis of evolved mutations underlying improvements in plant hemicellulose and cellulose fermentation by Clostridium phytofermentans.

    Directory of Open Access Journals (Sweden)

    Supratim Mukherjee

    Full Text Available The complexity of plant cell walls creates many challenges for microbial decomposition. Clostridium phytofermentans, an anaerobic bacterium isolated from forest soil, directly breaks down and utilizes many plant cell wall carbohydrates. The objective of this research is to understand constraints on rates of plant decomposition by Clostridium phytofermentans and identify molecular mechanisms that may overcome these limitations.Experimental evolution via repeated serial transfers during exponential growth was used to select for C. phytofermentans genotypes that grow more rapidly on cellobiose, cellulose and xylan. To identify the underlying mutations an average of 13,600,000 paired-end reads were generated per population resulting in ∼300 fold coverage of each site in the genome. Mutations with allele frequencies of 5% or greater could be identified with statistical confidence. Many mutations are in carbohydrate-related genes including the promoter regions of glycoside hydrolases and amino acid substitutions in ABC transport proteins involved in carbohydrate uptake, signal transduction sensors that detect specific carbohydrates, proteins that affect the export of extracellular enzymes, and regulators of unknown specificity. Structural modeling of the ABC transporter complex proteins suggests that mutations in these genes may alter the recognition of carbohydrates by substrate-binding proteins and communication between the intercellular face of the transmembrane and the ATPase binding proteins.Experimental evolution was effective in identifying molecular constraints on the rate of hemicellulose and cellulose fermentation and selected for putative gain of function mutations that do not typically appear in traditional molecular genetic screens. The results reveal new strategies for evolving and engineering microorganisms for faster growth on plant carbohydrates.

  11. Optimum fuel use in PWR reactors

    International Nuclear Information System (INIS)

    Neubauer, W.

    1979-07-01

    An optimization program was developed to calculate minimum-cost refuelling schedules for PWR reactors. Optimization was made over several cycles, without any constraints (equilibrium cycle). In developing the optimization program, special consideration was given to an individual treatment of every fuel element and to a sufficiently accurate calculation of all the data required for safe reactor operation. The results of the optimization program were compared with experimental values obtained at Obrigheim nuclear power plant. (orig.) [de

  12. Actual and potential use of population viability analyses in recovery of plant species listed under the US endangered species act.

    Science.gov (United States)

    Zeigler, Sara L; Che-Castaldo, Judy P; Neel, Maile C

    2013-12-01

    Use of population viability analyses (PVAs) in endangered species recovery planning has been met with both support and criticism. Previous reviews promote use of PVA for setting scientifically based, measurable, and objective recovery criteria and recommend improvements to increase the framework's utility. However, others have questioned the value of PVA models for setting recovery criteria and assert that PVAs are more appropriate for understanding relative trade-offs between alternative management actions. We reviewed 258 final recovery plans for 642 plants listed under the U.S. Endangered Species Act to determine the number of plans that used or recommended PVA in recovery planning. We also reviewed 223 publications that describe plant PVAs to assess how these models were designed and whether those designs reflected previous recommendations for improvement of PVAs. Twenty-four percent of listed species had recovery plans that used or recommended PVA. In publications, the typical model was a matrix population model parameterized with ≤5 years of demographic data that did not consider stochasticity, genetics, density dependence, seed banks, vegetative reproduction, dormancy, threats, or management strategies. Population growth rates for different populations of the same species or for the same population at different points in time were often statistically different or varied by >10%. Therefore, PVAs parameterized with underlying vital rates that vary to this degree may not accurately predict recovery objectives across a species' entire distribution or over longer time scales. We assert that PVA, although an important tool as part of an adaptive-management program, can help to determine quantitative recovery criteria only if more long-term data sets that capture spatiotemporal variability in vital rates become available. Lacking this, there is a strong need for viable and comprehensive methods for determining quantitative, science-based recovery criteria for

  13. Optimum gain and phase for stochastic cooling systems

    International Nuclear Information System (INIS)

    Meer, S. van der.

    1984-01-01

    A detailed analysis of optimum gain and phase adjustment in stochastic cooling systems reveals that the result is strongly influenced by the beam feedback effect and that for optimum performance the system phase should change appreciably across each Schottky band. It is shown that the performance is not greatly diminished if a constant phase is adopted instead. On the other hand, the effect of mixing between pick-up and kicker (which produces a phase change similar to the optimum one) is shown to be less perturbing than is usually assumed, provided that the absolute value of the gain is not too far from the optimum value. (orig.)

  14. Cadmium exposure pathways in a population living near a battery plant

    International Nuclear Information System (INIS)

    Hellstroem, Lennart; Persson, Bodil; Brudin, Lars; Grawe, Kierstin Petersson; Oborn, Ingrid; Jaerup, Lars

    2007-01-01

    Objectives: The objectives of the present study were to assess the relative impact of different pathways of environmental cadmium (Cd) exposure and to evaluate the contribution from locally produced vegetables and root crops to the total dietary intake of Cd. Methods: Cadmium in urine was determined for 492 individuals living near a closed down battery factory in Sweden. For each individual we created an environmental exposure-index based on Cd emissions to ambient air and number of years living at various distances from the plant. This information as well as dietary data were collected via questionnaires. Samples of soil, carrots and/or potatoes were collected from 37 gardens and analysed for Cd concentration. Results: Eating homegrown vegetables/potatoes, environmental Cd-exposure-index, female gender, age above 30 years and smoking more than one pack of cigarettes daily for at least 10 years were found to be significantly associated with increased urine concentrations of Cd (UCd > 1.0 nmol/mmol creatinine). We found a statistically significant relation between Cd in urine and environmental Cd-exposure-index in persons eating homegrown vegetables/potatoes regularly. Cd concentrations in homegrown carrots, potatoes and in garden soil were highest in the area closest to the factory. Daily consumption of potatoes and vegetables cultivated in the vicinity of the closed battery factory was estimated to increase Cd intake by 18-38%. Conclusion: The present study shows that consumption of locally grown vegetables and root crops was an important exposure pathway, in subjects living near a nickel-cadmium battery plant, whereas direct exposure via ambient air was less important

  15. Optimum coagulant forecasting by modeling jar test experiments using ANNs

    Science.gov (United States)

    Haghiri, Sadaf; Daghighi, Amin; Moharramzadeh, Sina

    2018-01-01

    Currently, the proper utilization of water treatment plants and optimizing their use is of particular importance. Coagulation and flocculation in water treatment are the common ways through which the use of coagulants leads to instability of particles and the formation of larger and heavier particles, resulting in improvement of sedimentation and filtration processes. Determination of the optimum dose of such a coagulant is of particular significance. A high dose, in addition to adding costs, can cause the sediment to remain in the filtrate, a dangerous condition according to the standards, while a sub-adequate dose of coagulants can result in the reducing the required quality and acceptable performance of the coagulation process. Although jar tests are used for testing coagulants, such experiments face many constraints with respect to evaluating the results produced by sudden changes in input water because of their significant costs, long time requirements, and complex relationships among the many factors (turbidity, temperature, pH, alkalinity, etc.) that can influence the efficiency of coagulant and test results. Modeling can be used to overcome these limitations; in this research study, an artificial neural network (ANN) multi-layer perceptron (MLP) with one hidden layer has been used for modeling the jar test to determine the dosage level of used coagulant in water treatment processes. The data contained in this research have been obtained from the drinking water treatment plant located in Ardabil province in Iran. To evaluate the performance of the model, the mean squared error (MSE) and correlation coefficient (R2) parameters have been used. The obtained values are within an acceptable range that demonstrates the high accuracy of the models with respect to the estimation of water-quality characteristics and the optimal dosages of coagulants; so using these models will allow operators to not only reduce costs and time taken to perform experimental jar tests

  16. Museum specimen data reveal emergence of a plant disease may be linked to increases in the insect vector population.

    Science.gov (United States)

    Zeilinger, Adam R; Rapacciuolo, Giovanni; Turek, Daniel; Oboyski, Peter T; Almeida, Rodrigo P P; Roderick, George K

    2017-09-01

    The emergence rate of new plant diseases is increasing due to novel introductions, climate change, and changes in vector populations, posing risks to agricultural sustainability. Assessing and managing future disease risks depends on understanding the causes of contemporary and historical emergence events. Since the mid-1990s, potato growers in the western United States, Mexico, and Central America have experienced severe yield loss from Zebra Chip disease and have responded by increasing insecticide use to suppress populations of the insect vector, the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae). Despite the severe nature of Zebra Chip outbreaks, the causes of emergence remain unknown. We tested the hypotheses that (1) B. cockerelli occupancy has increased over the last century in California and (2) such increases are related to climate change, specifically warmer winters. We compiled a data set of 87,000 museum specimen occurrence records across the order Hemiptera collected between 1900 and 2014. We then analyzed changes in B. cockerelli distribution using a hierarchical occupancy model using changes in background species lists to correct for collecting effort. We found evidence that B. cockerelli occupancy has increased over the last century. However, these changes appear to be unrelated to climate changes, at least at the scale of our analysis. To the extent that species occupancy is related to abundance, our analysis provides the first quantitative support for the hypothesis that B. cockerelli population abundance has increased, but further work is needed to link B. cockerelli population dynamics to Zebra Chip epidemics. Finally, we demonstrate how this historical macro-ecological approach provides a general framework for comparative risk assessment of future pest and insect vector outbreaks. © 2017 by the Ecological Society of America.

  17. Comparative analysis among the small RNA populations of source, sink and conductive tissues in two different plant-virus pathosystems.

    Science.gov (United States)

    Herranz, Mari Carmen; Navarro, Jose Antonio; Sommen, Evelien; Pallas, Vicente

    2015-02-22

    In plants, RNA silencing plays a fundamental role as defence mechanism against viruses. During last years deep-sequencing technology has allowed to analyze the sRNA profile of a large variety of virus-infected tissues. Nevertheless, the majority of these studies have been restricted to a unique tissue and no comparative analysis between phloem and source/sink tissues has been conducted. In the present work, we compared the sRNA populations of source, sink and conductive (phloem) tissues in two different plant virus pathosystems. We chose two cucurbit species infected with two viruses very different in genome organization and replication strategy; Melon necrotic spot virus (MNSV) and Prunus necrotic ringspot virus (PNRSV). Our findings showed, in both systems, an increase of the 21-nt total sRNAs together with a decrease of those with a size of 24-nt in all the infected tissues, except for the phloem where the ratio of 21/24-nt sRNA species remained constant. Comparing the vsRNAs, both PNRSV- and MNSV-infected plants share the same vsRNA size distribution in all the analyzed tissues. Similar accumulation levels of sense and antisense vsRNAs were observed in both systems except for roots that showed a prevalence of (+) vsRNAs in both pathosystems. Additionally, the presence of overrepresented discrete sites along the viral genome, hot spots, were identified and validated by stem-loop RT-PCR. Despite that in PNRSV-infected plants the presence of vsRNAs was scarce both viruses modulated the host sRNA profile. We compare for the first time the sRNA profile of four different tissues, including source, sink and conductive (phloem) tissues, in two plant-virus pathosystems. Our results indicate that antiviral silencing machinery in melon and cucumber acts mainly through DCL4. Upon infection, the total sRNA pattern in phloem remains unchanged in contrast to the rest of the analyzed tissues indicating a certain tissue-tropism to this polulation. Independently of the

  18. Assessment of Nuclear Power Plant Impact to the Environment: Effect of Sea Water Temperature Increase on Plankton Population

    International Nuclear Information System (INIS)

    Tjahaja, I P; Pujadi; Supriharyono; Aviati, N; Ruswahyun; Busono, H

    1996-01-01

    Research to study the effect of sea water temperature increase on plankton population had been carried out to predict nuclear power plant impact to the environment. Plankton collected from Jepara waters, Muria Peninsula, was grown on growth medium i.e. sea water enriched with silicate fertilizer. Plankton growth was maintained at temperature varied from 34oC to 46oC and the amount of plankton individu was counted twice a day until it was reduced about 95%. The results showed that the reduction of amount of plankton individu occurred on the medium with temperature above the ambient temperature (34oC). The rate of reduction is linear to the temperature increase. There is no plankton survived at temperature above 40oC for more than 24 hours

  19. Population dynamics in wastewater treatment plants with enhanced biological phosphorus removal operated with and without nitrogen removal

    DEFF Research Database (Denmark)

    Lee, N.; Jansen, J.l.C.; Aspegren, H.

    2002-01-01

    belonged to the β Proteobacteria, whereas the rest of the clusters belonged either to the Actinobacteria or to the α Proteobacteria. The relative abundance of Rhodocyclus-related bacteria in the activated sludge varied significantly in both systems during the whole period (from 6 to 18% in BNP, and from 4...... Proteobacteria (part of them Rhodocyclus-related, the identity of the rest unknown) and the Actinobacteria. However, not all of the Rhodocyclus-related bacteria showed 33Pi uptake. The P removal in the investigated plants is thus believed to be mediated by a mixed population consisting of a part...... of the Rhodocyclus-related bacteria, the Actinobacteria and other, yet unidentified bacteria....

  20. The optimum decision rules for the oddity task

    NARCIS (Netherlands)

    Versfeld, N.J.; Dai, H.; Green, D.M.

    1996-01-01

    This paper presents the optimum decision rule for an m-interval oddity task in which m-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur

  1. Optimum mobility’ facelift. Part 2 – the technique

    OpenAIRE

    Fanous, Nabil; Karsan, Naznin; Zakhary, Kristina; Tawile, Carolyne

    2006-01-01

    In the first of this two-part article on the ‘optimum mobility’ facelift, facial tissue mobility was analyzed, and three theories or mechanisms emerged: ‘intrinsic mobility’, ‘surgically induced mobility’ and ‘optimum mobility points’.

  2. Problem of determining optimum geological and technical measures

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, G N; Roste, Z A; Salimzhanov, E S

    1968-01-01

    This article is concerned with the mathematical simulation of oilfield operation, particularly the use of linear programing to determine optimum conditions for exploitation of a field. The basic approach is to define the field operation by a series of equations, apply boundary conditions and through an iterative computer technique find optimum operating conditions. Application of the method to Tuimazy field is illustrated.

  3. Optimum material gradient composition for the functionally graded ...

    African Journals Online (AJOL)

    This study investigates the relation between the material gradient properties and the optimum sensing/actuation design of the functionally graded piezoelectric beams. Three-dimensional (3D) finite element analysis has been employed for the prediction of an optimum composition profile in these types of sensors and ...

  4. Optimum unambiguous discrimination of linearly independent pure state

    DEFF Research Database (Denmark)

    Pang, Shengshi; Wu, Shengjun

    2009-01-01

    be satisfied by the optimum solution in different situations. We also provide the detailed steps to find the optimum measurement strategy. The method and results we obtain are given a geometrical illustration with a numerical example. Furthermore, using these equations, we derive a formula which shows a clear...

  5. Method for calculating individual equivalent doses and cumulative dose of population in the vicinity of nuclear power plant site

    International Nuclear Information System (INIS)

    Namestek, L.; Khorvat, D; Shvets, J.; Kunz, Eh.

    1976-01-01

    A method of calculating the doses of external and internal person irradiation in the nuclear power plant vicinity under conditions of normal operation and accident situations has been described. The main difference between the above method and methods used up to now is the use of a new antropomorphous representation of a human body model together with all the organs. The antropomorphous model of human body and its organs is determined as a set of simple solids, coordinates of disposistion of the solids, sizes, masses, densities and composition corresponding the genuine organs. The use of the Monte-Carlo method is the second difference. The results of the calculations according to the model suggested can be used for determination: a critical group of inhabitans under conditions of normal plant operation; groups of inhabitants most subjected to irradiation in the case of possible accident; a critical sector with a maximum collective dose in the case of an accident; a critical radioisotope favouring the greatest contribution to an individual equivalent dose; critical irradiation ways promoting a maximum contribution to individual equivalent doses; cumulative collective doses for the whole region or for a chosen part of the region permitting to estimate a population dose. The consequent method evoluation suggests the development of separate units of the calculationg program, critical application and the selection of input data of physical, plysiological and ecological character and improvement of the calculated program for the separate concrete events [ru

  6. Population dynamics of iron-oxidizing communities in pilot plants for the treatment of acid mine waters.

    Science.gov (United States)

    Heinzel, Elke; Janneck, Eberhard; Glombitza, Franz; Schlömann, Michael; Seifert, Jana

    2009-08-15

    The iron-oxidizing microbial community in two pilot plants for the treatment of acid mine water was monitored to investigate the influence of different process parameters such as pH, iron concentration, and retention time on the stability of the system to evaluate the applicability of this treatment technology on an industrial scale. The dynamics of the microbial populations were followed using T-RFLP (terminal restriction fragment length polymorphism) over a period of several months. For a more precise quantification, two TaqMan assays specific for the two prominent groups were developed and the relative abundance of these taxa in the iron-oxidizing community was verified by real-time PCR. The investigations revealed that the iron-oxidizing community was clearly dominated by two groups of Betaproteobacteria affiliated with the poorly known and not yet recognized species "Ferrovum myxofaciens" and with strains related to Gallionella ferruginea, respectively. These taxa dominated the microbial community during the whole investigation period and accelerated the oxidation of ferrous iron despite the changing characteristics of mine waters flowing into the plants. Thus, it is assumed that the treatment technology can also be applied to other mine sites and that these organisms play a crucial role in such treatment systems.

  7. Pharmacogenomics Implications of Using Herbal Medicinal Plants on African Populations in Health Transition

    Science.gov (United States)

    Thomford, Nicholas E.; Dzobo, Kevin; Chopera, Denis; Wonkam, Ambroise; Skelton, Michelle; Blackhurst, Dee; Chirikure, Shadreck; Dandara, Collet

    2015-01-01

    The most accessible points of call for most African populations with respect to primary health care are traditional health systems that include spiritual, religious, and herbal medicine. This review focusses only on the use of herbal medicines. Most African people accept herbal medicines as generally safe with no serious adverse effects. However, the overlap between conventional medicine and herbal medicine is a reality among countries in health systems transition. Patients often simultaneously seek treatment from both conventional and traditional health systems for the same condition. Commonly encountered conditions/diseases include malaria, HIV/AIDS, hypertension, tuberculosis, and bleeding disorders. It is therefore imperative to understand the modes of interaction between different drugs from conventional and traditional health care systems when used in treatment combinations. Both conventional and traditional drug entities are metabolized by the same enzyme systems in the human body, resulting in both pharmacokinetics and pharmacodynamics interactions, whose properties remain unknown/unquantified. Thus, it is important that profiles of interaction between different herbal and conventional medicines be evaluated. This review evaluates herbal and conventional drugs in a few African countries and their potential interaction at the pharmacogenomics level. PMID:26402689

  8. Rice-straw mulch reduces the green peach aphid, Myzus persicae (Hemiptera: Aphididae populations on kale, Brassica oleracea var. acephala (Brassicaceae plants.

    Directory of Open Access Journals (Sweden)

    Reinildes Silva-Filho

    Full Text Available Organic mulches, like peel and rice-straw, besides other materials affect the UV and temperature, which cause a reduction in the aphid arrival. The aim was to evaluate the effect of covering the soil with straw on the populations of the green peach aphid, Myzus persicae on the kale, Brassica oleracea var. acephala plants. The first experiment evaluated the direct effect of the rice-straw mulch and the second its indirect effect on aphid immigration, testing the plant characteristics that could lead to the landing preference of this insect. The third experiment evaluated the direct effect of the mulch on the aphid population. In the second and third experiments, four plants, each in a 14 L polyethylene pot with holes at the bottom, were used in areas with and without soil mulching. These pots were changed between areas, after seven days, to evaluate the effects of this change on the arrival of the winged aphids to the plants. Each plant was covered with anti-aphid gauze and inoculated with one winged M. persicae. Winged and apterous adults of this insect were counted per plant after 15 days. The temperature increased in the mulched plots to a maximum of 21-36°C and to 18-32°C in the plots with or without soil covering, respectively. Plant growth reduced the numbers of the winged aphids landing before and after they were moved to the bare soil plots. The nutrient content was similar in plants in both the mulched and no mulched plots. The population growth of M. persicae was higher in the control than in the mulched plots. This was partially due to temperatures close to 30°C in these plots and changes in the plant physiology. The soil mulching with rice-straw decreased the M. persicae landing, increased the plot temperatures and improved the vegetative growth of the kale plants.

  9. Rice-straw mulch reduces the green peach aphid, Myzus persicae (Hemiptera: Aphididae) populations on kale, Brassica oleracea var. acephala (Brassicaceae) plants.

    Science.gov (United States)

    Silva-Filho, Reinildes; Santos, Ricardo Henrique Silva; Tavares, Wagner de Souza; Leite, Germano Leão Demolin; Wilcken, Carlos Frederico; Serrão, José Eduardo; Zanuncio, José Cola

    2014-01-01

    Organic mulches, like peel and rice-straw, besides other materials affect the UV and temperature, which cause a reduction in the aphid arrival. The aim was to evaluate the effect of covering the soil with straw on the populations of the green peach aphid, Myzus persicae on the kale, Brassica oleracea var. acephala plants. The first experiment evaluated the direct effect of the rice-straw mulch and the second its indirect effect on aphid immigration, testing the plant characteristics that could lead to the landing preference of this insect. The third experiment evaluated the direct effect of the mulch on the aphid population. In the second and third experiments, four plants, each in a 14 L polyethylene pot with holes at the bottom, were used in areas with and without soil mulching. These pots were changed between areas, after seven days, to evaluate the effects of this change on the arrival of the winged aphids to the plants. Each plant was covered with anti-aphid gauze and inoculated with one winged M. persicae. Winged and apterous adults of this insect were counted per plant after 15 days. The temperature increased in the mulched plots to a maximum of 21-36°C and to 18-32°C in the plots with or without soil covering, respectively. Plant growth reduced the numbers of the winged aphids landing before and after they were moved to the bare soil plots. The nutrient content was similar in plants in both the mulched and no mulched plots. The population growth of M. persicae was higher in the control than in the mulched plots. This was partially due to temperatures close to 30°C in these plots and changes in the plant physiology. The soil mulching with rice-straw decreased the M. persicae landing, increased the plot temperatures and improved the vegetative growth of the kale plants.

  10. Regulation of Population Densities of Heterodera cajani and Other Plant-Parasitic Nematodes by Crop Rotations on Vertisols, in Semi-Arid Tropical Production Systems in India

    Science.gov (United States)

    Sharma, S. B.; Rego, T. J.; Mohiuddin, M.; Rao, V. N.

    1996-01-01

    The significance of double crop (intercrop and sequential crop), single crop (rainy season crop fallow from June to September), and rotations on densities of Heterodera cajani, Helicotylenchus retusus, and Rotylenchulus reniformis was studied on Vertisol (Typic Pellusterts) between 1987 and 1993. Cowpea (Vigna sinensis), mungbean (Phaseolus aureus), and pigeonpea (Cajanus cajan) greatly increased the population densities of H. cajani and suppressed the population densities of other plant-parasitic nematodes. Mean population densities of H. cajani were about 8 times lower in single crop systems than in double crop systems, with pigeonpea as a component intercrop. Plots planted to sorghum, safflower, and chickpea in the preceding year contained fewer H. cajani eggs and juveniles than did plots previously planted to pigeonpea, cowpea, or mungbean. Continuous cropping of sorghum in the rainy season and safflower in the post-rainy season markedly reduced the population density of H. cajani. Sorghum, safflower, and chickpea favored increased population densities of H. retusus. Adding cowpea to the system resulted in a significant increase in the densities of R. reniformis. Mean densities of total plant-parasitic nematodes were three times greater in double crop systems, with pigeonpea as a component intercrop than in single crop systems with rainy season fallow component. Cropping systems had a regulatory effect on the nematode populations and could be an effective nematode management tactic. Intercropping of sorghum with H. cajani tolerant pigeonpea could be effective in increasing the productivity of traditional production systems in H. cajani infested regions. PMID:19277141

  11. Differences in Competitive Ability between Plants from Nonnative and Native Populations of a Tropical Invader Relates to Adaptive Responses in Abiotic and Biotic Environments

    Science.gov (United States)

    Liao, Zhi-Yong; Zhang, Ru; Barclay, Gregor F.; Feng, Yu-Long

    2013-01-01

    The evolution of competitive ability of invasive plant species is generally studied in the context of adaptive responses to novel biotic environments (enemy release) in introduced ranges. However, invasive plants may also respond to novel abiotic environments. Here we studied differences in competitive ability between Chromolaena odorata plants of populations from nonnative versus native ranges, considering biogeographical differences in both biotic and abiotic environments. An intraspecific competition experiment was conducted at two nutrient levels in a common garden. In both low and high nutrient treatments, C. odorata plants from nonnative ranges showed consistently lower root to shoot ratios than did plants from native ranges grown in both monoculture and competition. In the low nutrient treatment, C. odorata plants from nonnative ranges showed significantly lower competitive ability (competition-driven decreases in plant height and biomass were more), which was associated with their lower root to shoot ratios and higher total leaf phenolic content (defense trait). In the high nutrient treatment, C. odorata plants from nonnative ranges showed lower leaf toughness and cellulosic contents (defense traits) but similar competitive ability compared with plants from native ranges, which was also associated with their lower root to shoot ratios. Our results indicate that genetically based shifts in biomass allocation (responses to abiotic environments) also influence competitive abilities of invasive plants, and provide a first potential mechanism for the interaction between range and environment (environment-dependent difference between ranges). PMID:23977140

  12. Fatty Acid Diversity is Not Associated with Neutral Genetic Diversity in Native Populations of the Biodiesel Plant Jatropha curcas L.

    Science.gov (United States)

    Martínez-Díaz, Yesenia; González-Rodríguez, Antonio; Rico-Ponce, Héctor Rómulo; Rocha-Ramírez, Víctor; Ovando-Medina, Isidro; Espinosa-García, Francisco J

    2017-01-01

    Jatropha curcas L. (Euphorbiaceae) is a shrub native to Mexico and Central America, which produces seeds with a high oil content that can be converted to biodiesel. The genetic diversity of this plant has been widely studied, but it is not known whether the diversity of the seed oil chemical composition correlates with neutral genetic diversity. The total seed oil content, the diversity of profiles of fatty acids and phorbol esters were quantified, also, the genetic diversity obtained from simple sequence repeats was analyzed in native populations of J. curcas in Mexico. Using the fatty acids profiles, a discriminant analysis recognized three groups of individuals according to geographical origin. Bayesian assignment analysis revealed two genetic groups, while the genetic structure of the populations could not be explained by isolation-by-distance. Genetic and fatty acid profile data were not correlated based on Mantel test. Also, phorbol ester content and genetic diversity were not associated. Multiple linear regression analysis showed that total oil content was associated with altitude and seasonality of temperature. The content of unsaturated fatty acids was associated with altitude. Therefore, the cultivation planning of J. curcas should take into account chemical variation related to environmental factors. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  13. Scientific Opinion on the risks to plant health posed by European versus non-European populations of the potato cyst nematodes Globodera pallida and Globodera rostochiensis

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2012-01-01

    The Panel on Plant Health has delivered a scientific opinion on the different risks posed by European and non-European populations of the potato cyst nematodes (PCN) Globodera pallida and Globodera rostochiensis to solanaceous plants in the EU and on the effectiveness of current control measures...... to place of production freedom and soil origin were noted, and the Panel identified additional risk reduction options for certain plants for planting (e.g. bulbs) and additional requirements to confirm the absence of PCN in places of production. The Panel also identified some problems with the existing...... control measures to reduce the spread of PCN within the EU. A thorough and well-coordinated EU-wide survey using standardized methods would be necessary to evaluate the need to maintain these measures. The monitoring of PCN populations should exploit new diagnostic techniques (e.g. mitochondrial DNA...

  14. Plant population structure and insect herbivory on Solanum mauritianum Scopoli (Solanaceae in southern Brazil: a support to biological control

    Directory of Open Access Journals (Sweden)

    Deise Mari Barboza

    2009-04-01

    Full Text Available Solanum mauritianum Scopoli (Solanaceae, a native Brazilian shrub, has become naturalized and invasive in several countries. In South Africa, where invasions are severe, herbivorous insects that attack S. mauritianum in its native area have been considered for introduction as biological control agents. To assess the action of such herbivores on the plant, studies were carried out on a population of S. mauritianum in an area undergoing regeneration in southern Brazil. An analysis of the structure of that population was performed, as well as of herbivory by insects, in particular of Anthonomus (Curculionidae. The population structure showed an "inverted J" pattern in diameter classes, but not in height classes. Individual plants showed an aggregate distribution. The damage caused by Anthonomus did not amount to the loss of a large leaf area, but since it was inflicted on young leaves and in a large proportion, could lead to the survival decrease.Solanum mauritianum Scopoli (Solanaceae, um arbusto endêmico do sul do Brasil, naturalizou-se e tornou-se invasor em vários países do mundo. Na África do Sul, onde as invasões são severas, insetos fitófagos associados à planta no país de origem têm sido considerados para introdução como agentes de controle biológico. Para avaliar a ação de tais insetos no ambiente natural, foram conduzidos estudos em uma população de S. mauritianum em uma área em regeneração no sul do Brasil. Foi realizada análise da estrutura populacional, bem como da herbivoria causada por insetos, em particular para uma espécie do gênero Anthonomus (Curculionidae, para subsidiar o trabalho sobre controle biológico. A estrutura da população mostrou um padrão "J invertido" nas classes de diâmetro, mas não nas classes de altura; a distribuição espacial dos indivíduos era agregada. O dano causado por Anthonomus sp. não refletiu na perda real de grande área foliar. No entanto, uma vez que foi detectada uma

  15. QTL Analysis and Nested Association Mapping for Adult Plant Resistance to Powdery Mildew in Two Bread Wheat Populations

    Directory of Open Access Journals (Sweden)

    Yan Ren

    2017-07-01

    Full Text Available CIMMYT wheat (Triticum aestivum L. lines Francolin#1 and Quaiu#3 displayed effective and stable adult plant resistance (APR to Chinese Blumeria graminis f. sp. tritici isolates in the field. To elucidate their genetic basis of resistance, two recombinant inbred line (RIL populations of their crosses with Avocet, the susceptible parent, were phenotyped in Zhengzhou and Shangqiu in the 2014–2015 and 2015–2016 cropping seasons. These populations were also genotyped with SSR (simple sequence repeat markers and DArT (diversity arrays technology markers. Two common significant quantitative trait loci (QTL on wheat chromosomes 1BL and 4BL were detected in both populations by joint and individual inclusive composite interval mapping, explaining 20.3–28.7% and 9.6–15.9% of the phenotypic variance in Avocet × Francolin#1 and 4.8–11.5% and 10.8–18.9% in Avocet × Quaiu#3, respectively. Additional QTL were mapped on chromosomes 1DL and 5BL in Avocet × Francolin#1 and on 2DL and 6BS in Avocet × Quaiu#3. Among these, QPm.heau-1DL is probably a novel APR gene contributing 6.1–8.5% of total phenotypic variance. The QTL on 1BL corresponds to the pleiotropic multi-pathogen resistance gene Yr29/Lr46/Pm39, whereas the QTL on 2DL maps to a similar region where stripe rust resistance gene Yr54 is located. The QTL identified can potentially be used for the improvement of powdery mildew and rust resistance in wheat breeding.

  16. Development of antimicrobial optimum glass ionomer

    International Nuclear Information System (INIS)

    Angioletto, E.; Tezza, V.B.; Santos, M.J.; Montedo, O.R.K.; Pich, C.T.; Fiori, M.A.; Angioletto, Ev.

    2010-01-01

    The use of glass ionomer for restorations in dentistry for lower income population is a well established practice in public clinics of Brazil. However the average price of this kind of material and its low durability still have a negative impact on public health for being imported and frequently replaced it becomes expensive for the manufacturers and for public agencies. In glass ionomer the main antimicrobial agent is fluoride, which is released gradually. The material used for filling provides an average life of five years and its durability can be increased if the ionomer contains other oligodynamic elements. It was formulated, merged a new optimized glass ionomer which was characterized by X-ray diffraction, ion measurement and antimicrobial activity. This new product showed promising results, that pointed structural stability an increase of antimicrobial efficiency. (author)

  17. Effect of Planting Patterns' and Plant Population on Some of Morphological Traits, Harvest Index and Conservable Grain Yield of Sweet Corn

    Directory of Open Access Journals (Sweden)

    M. Nasrolah Alhossini

    2012-04-01

    Full Text Available Sweet corn is one of the most important crops in Iran and due to its short period of growth, it has been an important position after wheat and barley in khorasane Razavi Province. In this study two methods of planting (one raised bed and furrow planting and 3 plant densities (65000, 75000 and 85000 plant/ha was evaluated on some of Morphological Traits, harvest index and conservable grain yield of sweet Corn(Chase and KSC403su Varieties in Torbat-e-Heidarie in saline (4.060ds/m condition on 2009. The experimental design was factorial based on RCBC with 4 replications. The result of ANOVA showed significant differences between Anthesis silking interval (ASI, tassel length, plant height, ear height, stem diameter, harvest index, and conservable grain yield of sweet corn varieties that effected by planting methods. the highest harvest index was belonged to Chase in 75000 Plant/ha on one raised bed planting method with 31.75% and the lowest mean was belonged to KSC403su in 85000 Plant/ha on furrow planting method with 14.93%. In addition the highest grain yield was belonged to chase variety at 75000 plant/ha and furrow planting method with 11.912 ton/ha, while the lowest grain yield was belonged to KSC403su variety at 85000 plant/ha and raised bed planting (3.610 ton/ha. The Chase variety was better than KSC403su Due to its canopy and photo period is shorter than KSC403su. The superiority of Chase variety can be related to better distribution of leaves, highest harvest index, conservable grain yield and plant arrangement in the row.

  18. Size asymmetry in intraspecific competition and the density-dependence of inbreeding depression in a natural plant population: a case study in cassava (Manihot esculenta Crantz, Euphorbiaceae).

    Science.gov (United States)

    Pujol, B; McKey, D

    2006-01-01

    The effects of competition on the genetic composition of natural populations are not well understood. We combined demography and molecular genetics to study how intraspecific competition affects microevolution in cohorts of volunteer plants of cassava (Manihot esculenta) originating from seeds in slash-and-burn fields of Palikur Amerindians in French Guiana. In this clonally propagated crop, genotypic diversity is enhanced by the incorporation of volunteer plants into farmers' stocks of clonal propagules. Mortality of volunteer plants was density-dependent. Furthermore, the size asymmetry of intraspecific competition increased with local clustering of plants. Size of plants was correlated with their multilocus heterozygosity, and stronger size-dependence of survival in clusters of plants, compared with solitary plants, increased the magnitude of inbreeding depression when competition was severe. The density-dependence of inbreeding depression of volunteer plants helps explain the high heterozygosity of volunteers that survive to harvest time and thus become candidates for clonal propagation. This effect could help favour the maintenance of sex in this 'vegetatively' propagated crop plant.

  19. Response of False horn plantain to different plant densities and ...

    African Journals Online (AJOL)

    The study, which was carried out at the Crops Research Institute, Kumasi, Ghana, from April 1992 to March 1995, aimed at determining (i) the optimum plant density of False horn plantain for maximum yield, and (ii) the optimum frequency of handweeding for economic returns. Results indicated that the optimum plant density ...

  20. Investigation of earthquake factor for optimum tuned mass dampers

    Science.gov (United States)

    Nigdeli, Sinan Melih; Bekdaş, Gebrail

    2012-09-01

    In this study the optimum parameters of tuned mass dampers (TMD) are investigated under earthquake excitations. An optimization strategy was carried out by using the Harmony Search (HS) algorithm. HS is a metaheuristic method which is inspired from the nature of musical performances. In addition to the HS algorithm, the results of the optimization objective are compared with the results of the other documented method and the corresponding results are eliminated. In that case, the best optimum results are obtained. During the optimization, the optimum TMD parameters were searched for single degree of freedom (SDOF) structure models with different periods. The optimization was done for different earthquakes separately and the results were compared.

  1. Research project: "Promotion of optimum brain ageing"

    CERN Multimedia

    IT Department

    2009-01-01

    The Rehabilitation and Geriatrics Department of the Geneva University Hospitals (HUG) has signed a research protocol with CERN with a view to promoting better understanding of the mechanisms that trigger Alzheimer’s disease. Alzheimer’s disease is a form of dementia associated with memory loss, inability to make plans and spatial disorientation. With 24 million sufferers worldwide at present, a figure that is predicted to rise to 29 million by 2020, it represents a major challenge for the coming decades. Prevention is a key factor in slowing the alarming spread of this disease. Delaying the onset of the disease could reduce the total number of cases by 50%. Why CERN? CERN is an international research organisation with a workforce that is predominantly male (a section of the population that has been little studied so far) and has a high level of education. Moreover, its pensioners are easy to reach since the majority live in the Geneva area. The aim of the study is to ev...

  2. Optimum survey methods when interviewing employed women.

    Science.gov (United States)

    Dunning, Kari; LeMasters, Grace K

    2009-02-01

    While survey studies have examined bias much is unknown regarding specific subpopulations, especially women workers. A population based phone, Internet, and mail survey of workplace falls during pregnancy was undertaken. Participation by industry and occupation and survey approach and bias, reliability, and incomplete data were examined. Of the 3,997 women surveyed, 71% were employed during their pregnancy. Internet responders were most likely to be employed while pregnant and to report a workplace fall at 8.8% compared to 5.8% and 6.1% for mail and phone respondents. Internet responders had the most missing employment data with company name missing for 17.9% compared to 1.3% for phone responders. Mail surveys were best for recruiting those employed in eight of nine industries, and this was especially true for service occupations. To decrease bias and increase participation, mixed approaches may be useful with particular attention for collecting occupational data. Am. J. Ind. Med. 52:105-112, 2009. (c) 2008 Wiley-Liss, Inc.

  3. Genetic variability of wild populations of Leporinus elongatus in the São Domingos River - MS Brazil: a preliminary view on the construction of the hydroelectric plant

    Directory of Open Access Journals (Sweden)

    Ricardo Pereira Ribeiro

    2016-09-01

    Full Text Available Most of the electricity used in Brazil comes from hydroelectric plants, mainly due to the great availability of its water resources. However, the construction of these plants denotes serious problems related to migration of native fish and the genetic conservation of stocks. Current study evaluates two wild population of Leporinus elongatus (piapara located downstream (Population A - PopA and upstream (Population B - PopB of the Cachoeira Branca before the construction of the São Domingos hydroelectric plant (HPP in the Mato Grosso do Sul State, Brazil. Thirty samples from caudal fins were collected and analyzed for each population. Eighty-nine fragments, including 72 polymorphic ones (80.9%, were analyzed. Low fragments (less than 0.100 in both populations (PopA = 2 and PopB = 3 were identified. Nine fixed fragments (frequency 1.000 (PopA = 3 and PopB = 6, and four exclusive fragments (PopA = 3 and PopB = 1 were also reported. The genetic variability within populations, calculated by Shannon Index and by percentage of polymorphic fragments, indicated high rates of intrapopulation variability (PopA = 0.309 and 61.80% and PopB = 0.392 and 71.90%, respectively. Genetic distance and identity rates (0.089 and 0.915, respectively were different between populations, whilst AMOVA showed that most variations lie within the populations and not between them. Fst and Nm rates showed moderate genetic differentiation with low numbers of migrants. Results reveal populations with high intra-population genetic variability and genetic differentiation, with low gene flow. The passage ladders of São Domingos HPP should control fish transposition to preserve genetic variability.

  4. Effects of copper-based compounds, antibiotics and a plant activator on population sizes and spread of Clavibacter michiganensis subsp. michiganensis in greenhouse tomato seedlings

    OpenAIRE

    Milijašević Svetlana; Todorović Biljana; Potočnik Ivana; Rekanović Emil; Stepanović Miloš

    2009-01-01

    Three copper-based compounds (copper hydroxide, copper oxychloride, copper sulphate), two antibiotics (streptomycin and kasugamycin) and a plant activator (ASM) significantly reduced population sizes and spread of C. michiganensis subsp. michiganensis among tomato seedlings in the greenhouse. Streptomycin had the best effect in reducing pathogen population size in all sampling regions. Moreover, this antibiotic completely stopped the spread of C. michiganensis subsp. michiganensis in the regi...

  5. Population Growth and Its Impact on the Design Capacity and Performance of the Wastewater Treatment Plants in Sedibeng and Soshanguve, South Africa

    Science.gov (United States)

    Teklehaimanot, Giorgis Z.; Kamika, I.; Coetzee, M. A. A.; Momba, M. N. B.

    2015-10-01

    This study investigated the effects of population growth on the performance of the targeted wastewater treatment plants in Sedibeng District and Soshanguve peri-urban area, South Africa. The impact of population growth was assessed in terms of plant design, operational capacity (flow rate) and other treatment process constraints. Between 2001 and 2007, the number of households connected to the public sewerage service increased by 15.5, 17.2 and 37.8 % in Emfuleni, Lesedi and Midvaal Local Municipalities, respectively. Soshanguve revealed a 50 % increment in the number of households connected to the sewerage system between 1996 and 2001. Except for Sandspruit (-393.8 %), the rate of influent flows received by Meyerton increased by 6.8 ML/day (67.8 %) and 4.7 ML/day (46.8 %) during the dry and wet seasons, respectively. The flow rate appeared to increase during the wet season by 6.8 ML/day (19.1 %) in Leeuwkuil and during the dry season by 0.8 ML/day (3.9 %) in Rietgat. Underperformance of the existing wastewater treatment plants suggests that the rapid population growth in urban and peri-urban areas (hydraulic overloading of the wastewater treatment plants) and operational constraints (overflow rate, retention time, oxygen supply capacity of the plants and chlorine contact time) resulted in the production of poor quality effluents in both selected areas. This investigation showed that the inefficiency of Meyerton Wastewater Treatment Plant was attributed to the population growth (higher volumes of wastewater generated) and operational constraints, while the cause of underperformance in the other three treatment plants was clearly technical (operational).

  6. Effects of Copper-based Compounds, Antibiotics and a Plant Activator on Population Sizes and Spread of Clavibacter michiganensis subsp. michiganensis in Greenhouse Tomato Seedlings

    Directory of Open Access Journals (Sweden)

    Svetlana Milijašević

    2009-01-01

    Full Text Available Three copper-based compounds (copper hydroxide, copper oxychloride, copper sulphate, two antibiotics (streptomycin and kasugamycin and a plant activator (ASM significantly reduced population sizes and spread of C. michiganensis subsp. michiganensis among tomatoseedlings in the greenhouse. Streptomycin had the best effect in reducing pathogen population size in all sampling regions. Moreover, this antibiotic completely stopped the spread of C. michiganensis subsp. michiganensis in the region most distant from the inoculumfocus. Copper hydroxide mixed with streptomycin significantly limited the pathogen population, compared with copper hydroxide alone, the other copper-based compounds, ASM and kasugamycin. However, combining streptomycin with copper hydroxide did notcontribute to its greater efficacy against the pathogen population. Copper-based compounds, in general, were less effective in limiting pathogen population sizes than the other treatments in all three sampling regions, primarily copper oxychloride and the combinationof copper hydroxide and mancozeb. Among copper compounds, copper hydroxide was the most prominent in reducing the bacterial population, especially in the region closest to the inoculum focus, while its combination with mancozeb did not improve the effects. Kasugamycin significantly limited pathogen population size, compared to copper bactericides, but it was less effective than the other antibiotic compound, i.e. streptomycin. The plant activator ASM significantly reduced population density, and it was more effectivewhen used three days prior to inoculation than six days before inoculation.

  7. Characterization of acetate-utilizing methanogenic bacteria, depending on varying acetate concentrations, in a biogas plant. Phase 1

    International Nuclear Information System (INIS)

    Ahring, B.K.

    1994-12-01

    The present report contains the results of a project concerning behaviour of acetate-utilizing methanogenic bacteria in mesophilic and thermophilic biogas plants, collected in 1992 - 1994 period. Labelled acetates (2-C 14 -CH 3 COOH) have been used to characterize the types of methane bacteria populations in the Danish biogas plants, the optimum acetate concentration for these bacteria and acetate metabolism in mesophilic and thermophilic biogas reactors with low acetate concentrations. 2 publications are included. (EG)

  8. The decrease in the population of Gluconacetobacter diazotrophicus in sugarcane after nitrogen fertilization is related to plant physiology in split root experiments.

    Science.gov (United States)

    Rodríguez-Andrade, Osvaldo; Fuentes-Ramírez, Luis E; Morales-García, Yolanda E; Molina-Romero, Dalia; Bustillos-Cristales, María R; Martínez-Contreras, Rebeca D; Muñoz-Rojas, Jesús

    2015-01-01

    It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH(4)NO(3) on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8mM of NH(4)NO(3) (640mgN/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH(4)NO(3) (0.35mM; 10mgN/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH(4)NO(3) (6.3mM; 180 mgN/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH4NO3 (100dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Optimum Temperature and Thermal Stability of Crude Polyphenol ...

    African Journals Online (AJOL)

    The optimum temperature was found to be 300C for the enzyme extracted from guava, ... processing industries because during the processing ... enhance the brown colour produced (Valero et al., ... considerable economic and nutritional loss.

  10. Performance characteristics of aerodynamically optimum turbines for wind energy generators

    Science.gov (United States)

    Rohrbach, C.; Worobel, R.

    1975-01-01

    This paper presents a brief discussion of the aerodynamic methodology for wind energy generator turbines, an approach to the design of aerodynamically optimum wind turbines covering a broad range of design parameters, some insight on the effect on performance of nonoptimum blade shapes which may represent lower fabrication costs, the annual wind turbine energy for a family of optimum wind turbines, and areas of needed research. On the basis of the investigation, it is concluded that optimum wind turbines show high performance over a wide range of design velocity ratios; that structural requirements impose constraints on blade geometry; that variable pitch wind turbines provide excellent power regulation and that annual energy output is insensitive to design rpm and solidity of optimum wind turbines.

  11. Optimum strategies for nuclear energy system development (method of synthesis)

    International Nuclear Information System (INIS)

    Belenky, V.Z.

    1983-01-01

    The problem of optimum long-term development of the nuclear energy system is considered. The optimum strategies (i.e. minimum total uranium consumption) for the transition phase leading to a stationary regime of development are found. For this purpose the author has elaborated a new method of solving linear problems of optimal control which can include jumps in trajectories. The method gives a possibility to fulfil a total synthesis of optimum strategies. A key characteristic of the problem is the productivity function of the nuclear energy system which connects technological system parameters with its growth rate. There are only two types of optimum strategies, according to an increasing or decreasing productivity function. Both cases are illustrated with numerical examples. (orig.) [de

  12. Experimental validation of optimum resistance moment of concrete ...

    African Journals Online (AJOL)

    Experimental validation of optimum resistance moment of concrete slabs reinforced ... other solutions to combat corrosion problems in steel reinforced concrete. ... Eight specimens of two-way spanning slabs reinforced with CFRP bars were ...

  13. Optimum tungsten content in high strength 9 to 12% chromium containing creep resistant steels

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Muraki, T.; Mimura, H.

    2000-01-01

    Tungsten containing ferritic creep resistant steels are the candidate materials for ultra-super-critical fossil power plant because of their high creep rupture strength. But the strengthening mechanisms by tungsten addition have not yet been completely studied. In this report, creep rupture time and creep strain rate measurement decided the optimum tungsten content in 9 to 12% chromium ferritic steels. The precipitation behavior of Laves phase and the precise discussion of creep strain rate analyses explain the contribution of Laves phase at the lath boundary and the contribution of tungsten in solid solution. P92 contains the optimum amount of tungsten and chromium, 1.8 mass% and 9 mass% respectively judging from the creep rupture strength point of view. (orig.)

  14. Optimum motion track planning for avoiding obstacles

    International Nuclear Information System (INIS)

    Attia, A.A.A

    2008-01-01

    A genetic algorithm (GA) is a stochastic search and optimization technique based on the mechanism of natural selection. A population of candidate solutions (Chromosomes) is held and interacts over a number of iterations (Generations) to produce better solutions. In canonical GA, the chromosomes are encoded as binary strings. Driving the process is the fitness of the chromosomes, which relates the quality of a candidate in quantitative terms. The fitness function encapsulates the problem- specific knowledge. The fitness is used in a stochastic selection of pairs of chromosomes which are 'reproduced' to generate new solution strings. Reproduction involves crossover, which generates new children by combining chromosomes in a process which swaps portions of each others genes. The other reproduction operator is called mutation. Mutation randomly changes genes and is used to introduce new information into the search. Both crossover and mutation make heavy use of random numbers.The aim of this thesis is to investigate the H/W implementation of genetic algorithm based motion path planning of robot. The potential benefit of using genetic algorithm hardware is that it allows both the huge parallelism which is suited to random number generation, crossover, mutation and fitness evaluation. For many real-world applications, GA can run for days, even when it is executed on a high performance workstation. According to the extensive computation of GA, it follows that hardware-based GA has been put forward. There are aspects of GA approach attract H/W implementation. The operation of selection and reproduction are basically problem independent and involve basic string manipulation tasks. These can be achieved by logical circuits.The fitness evaluation task, which is problem dependent, however proves a major difficulty in H/W implementation. Another difficulty comes from that designs can only be used for the individual problem their fitness function represents. Therefore, in this

  15. Optimum filters for narrow-band frequency modulation.

    Science.gov (United States)

    Shelton, R. D.

    1972-01-01

    The results of a computer search for the optimum type of bandpass filter for low-index angle-modulated signals are reported. The bandpass filters are discussed in terms of their low-pass prototypes. Only filter functions with constant numerators are considered. The pole locations for the optimum filters of several cases are shown in a table. The results are fairly independent of modulation index and bandwidth.

  16. Genetic differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) populations on cultivated cowpea and wild host plants: implications for insect resistance management and biological control strategies

    Science.gov (United States)

    Maruca vitrata is a polyphagous insect pest on a wide variety of leguminous plants in the tropics and subtropics. The contribution of host-associated genetic variation on population structure was investigated using analysis mitochondrial cox1 sequence and microsatellite marker data from M. vitrata c...

  17. Effect of power plant condenser coolant discharge on population density of intertidal bivalve Donax cuneatus (L. 1758)

    International Nuclear Information System (INIS)

    Jahir Hussain, K.; Mohanty, A.K.; Prasad, M.V.R.; Satpathy, K.K.

    2008-01-01

    Impact of thermal discharge from a coastal power station (Madras Atomic Power Station, south-east coast of India) on the spatial variability of Donax cuneatus abundance was assessed to determine the impact boundary. Totally twenty sites were selected both on south and north side of effluents mixing zone in increasing spatial scale. Twelve locations were selected towards south side at a distance from 0 (near mixing point) to 2000 m and eight locations were selected towards north from the effluent mixing zone. The present study was conducted during January 2008. Mean water temperature along the coast ranged from 29.1 ± 0.1 - 31.2 ± 0.1 deg C. Total organic carbon content in the sediment ranged from 0.27 to 0.70%. D. cuneatus population in the swash zone ranged between 1.3 ± 1.5 to 88.3 ± 9.6 m -2 . Meager population of the wedge clam was observed up to 100 m south from mixing point and abundance gradually increased with increasing distance from the mixing zone. Comparatively high abundance was observed from 400 m; the density reached maximum at 1000 m (64.0 ± 3.6 m -2 ). Similar pattern was observed on north side too but less abundance was observed only up to 80m. Maximum abundance was observed (88.3 ± 9.6 m -2 ) at control location located 500 m north of the discharge point. 40 m on either side of discharge point were highly impacted, 80 to 100m towards plume flow (south) were moderately impacted and 80 m north of mixing point also witnessed moderate impact. After 100 m, effluents did not affect the northern side, whereas between 100 to 400 m, south was influenced slightly. Multivariate clustering pattern on the environmental variables of all sampling locations and abundance pattern of D. cuneatus showed similarity. Present investigation unambiguously showed that the abundance pattern of D. cuneatus on the sandy beach of Kalpakkam is not governed by single major factor but is influenced by multiple interacting factors. The population size of the wedge clam

  18. Studies on Plant Population and Stand Establishment Techniques for Increasing Productivity of Rice in Dera Ismail Khan, Pakistan

    Directory of Open Access Journals (Sweden)

    Mohammad Safdar BALOCH

    2007-06-01

    Full Text Available Rice production in Pakistan is constraint by many factors pertaining to prevalent planting techniques. A research on the feasibility of new planting techniques (direct seeding on flat, transplanting on flat, direct seeding on ridges, transplanting on ridges and parachute planting in transplanted and direct wet-seeded rice was undertaken at Dera Ismail Khan region of Pakistan's North West Frontier Province during 2002 and 2003. Among the planting techniques, the best performance for the yield formation and economic evaluation was noted for transplanting on flat during both years. Chinese parachute planting technology also showed very promising results in most of the parameters. Direct seeding on ridges could not excel transplanting on flat and parachute planting during both cropping seasons. The findings concluded the feasibility of parachute planting technology along with traditional rice transplanting on flat over all other planting techniques being practiced in the area.

  19. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 5. Control of population densities surrounding nuclear power plants

    International Nuclear Information System (INIS)

    Nero, A.V.; Schroeder, C.H.; Yen, W.W.S.

    1977-01-01

    In view of the requirement that the California Energy Resources Conservation and Development Commission must specify land-use/population-density control measures to be used in the vicinity of nuclear power plants being granted land use, the possible forms of such measures are examined. Since these measures must maintain population densities below Nuclear Regulatory Commission criteria, if appropriate, NRC criteria for land use and population densities are given particular attention. In addition, a preliminary comparison of the cost of possible control measures with the reduced potential for damage to the public health and safety is made, yielding the result that control measures within approximately one mile of the plant site may be justified, in certain cases, on a strictly cost-benefit basis. However, it is not clear whether controls over such a limited region would satisfy the legal mandate

  20. The temporal distribution of directional gradients under selection for an optimum.

    Science.gov (United States)

    Chevin, Luis-Miguel; Haller, Benjamin C

    2014-12-01

    Temporal variation in phenotypic selection is often attributed to environmental change causing movements of the adaptive surface relating traits to fitness, but this connection is rarely established empirically. Fluctuating phenotypic selection can be measured by the variance and autocorrelation of directional selection gradients through time. However, the dynamics of these gradients depend not only on environmental changes altering the fitness surface, but also on evolution of the phenotypic distribution. Therefore, it is unclear to what extent variability in selection gradients can inform us about the underlying drivers of their fluctuations. To investigate this question, we derive the temporal distribution of directional gradients under selection for a phenotypic optimum that is either constant or fluctuates randomly in various ways in a finite population. Our analytical results, combined with population- and individual-based simulations, show that although some characteristic patterns can be distinguished, very different types of change in the optimum (including a constant optimum) can generate similar temporal distributions of selection gradients, making it difficult to infer the processes underlying apparent fluctuating selection. Analyzing changes in phenotype distributions together with changes in selection gradients should prove more useful for inferring the mechanisms underlying estimated fluctuating selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  1. Dispersion of radioactive material in air and water and consideration of population distribution in site evaluation for nuclear power plants. Safety guide

    International Nuclear Information System (INIS)

    2002-01-01

    The IAEA issues Safety Requirements and Safety Guides pertaining to nuclear power plants and activities in the field of nuclear energy, on the basis of its Safety Fundamentals publication on The Safety of Nuclear Installations. The present Safety Guide, which supplements the Code on the Safety of Nuclear Power Plants: Siting, concerns the effects of a nuclear power plant on the surrounding region and the consideration of population distribution in the siting of a plant. This Safety Guide makes recommendations on how to meet the requirements of the Code on the Safety of Nuclear Power Plants: Siting, on the basis of knowledge of the mechanisms for the dispersion of effluents discharged into the atmosphere and into surface water and groundwater. Relevant site characteristics and safety considerations are discussed. Population distribution, the projected population growth rate, particular geographical features, the capabilities of local transport networks and communications networks, industry and agriculture in the region, and recreational and institutional activities in the region should be considered in assessing the feasibility of developing an emergency response plan. In the selection of a site for a facility using radioactive material, such as a nuclear power plant, account should be taken of any local features that might be affected by the facility and of the feasibility of off-site intervention, including emergency response and protective actions. This is in addition to the evaluation of any features of the site itself that might affect the safety of the facility. This Safety Guide recommends methods for the assessment of regional and local characteristics. This Safety Guide supersedes four earlier IAEA Safety Guides, namely: Atmospheric Dispersion in Nuclear Power Plant Siting (Safety Series No. 50-SG-S3 (1980)); Site Selection and Evaluation for Nuclear Power Plants with Respect to Population Distribution (Safety Series No. 50-SG-S4 (1980)); Hydrological

  2. Dispersion of radioactive material in air and water and consideration of population distribution in site evaluation for nuclear power plants. Safety guide

    International Nuclear Information System (INIS)

    2004-01-01

    The IAEA issues Safety Requirements and Safety Guides pertaining to nuclear power plants and activities in the field of nuclear energy, on the basis of its Safety Fundamentals publication on The Safety of Nuclear Installations. The present Safety Guide, which supplements the Code on the Safety of Nuclear Power Plants: Siting, concerns the effects of a nuclear power plant on the surrounding region and the consideration of population distribution in the siting of a plant. This Safety Guide makes recommendations on how to meet the requirements of the Code on the Safety of Nuclear Power Plants: Siting, on the basis of knowledge of the mechanisms for the dispersion of effluents discharged into the atmosphere and into surface water and groundwater. Relevant site characteristics and safety considerations are discussed. Population distribution, the projected population growth rate, particular geographical features, the capabilities of local transport networks and communications networks, industry and agriculture in the region, and recreational and institutional activities in the region should be considered in assessing the feasibility of developing an emergency response plan. In the selection of a site for a facility using radioactive material, such as a nuclear power plant, account should be taken of any local features that might be affected by the facility and of the feasibility of off-site intervention, including emergency response and protective actions. This is in addition to the evaluation of any features of the site itself that might affect the safety of the facility. This Safety Guide recommends methods for the assessment of regional and local characteristics. This Safety Guide supersedes four earlier IAEA Safety Guides, namely: Atmospheric Dispersion in Nuclear Power Plant Siting (Safety Series No. 50-SG-S3 (1980)). Site Selection and Evaluation for Nuclear Power Plants with Respect to Population Distribution (Safety Series No. 50-SG-S4 (1980)). Hydrological

  3. Estimation of fuel burning rate and heating value with highly variable properties for optimum combustion control

    International Nuclear Information System (INIS)

    Hsi, C.-L.; Kuo, J.-T.

    2008-01-01

    Estimating solid residue gross burning rate and heating value burning in a power plant furnace is essential for adequate manipulation to achieve energy conversion optimization and plant performance. A model based on conservation equations of mass and thermal energy is established in this work to calculate the instantaneous gross burning rate and lower heating value of solid residue fired in a combustion chamber. Comparing the model with incineration plant control room data indicates that satisfactory predictions of fuel burning rates and heating values can be obtained by assuming the moisture-to-carbon atomic ratio (f/a) within the typical range from 1.2 to 1.8. Agreement between mass and thermal analysis and the bed-chemistry model is acceptable. The model would be useful for furnace fuel and air control strategy programming to achieve optimum performance in energy conversion and pollutant emission reduction

  4. Planning priority conservation areas under climate change for six plant species with extremely small populations in China

    Directory of Open Access Journals (Sweden)

    Hong Qu

    2018-03-01

    Full Text Available The concept of Plant Species with Extremely Small Populations (PSESP has been employed to guide conservation of threatened plant species in China. Climate change has a high potential to threaten PSESP. As a result, it is necessary to integrate climate change effects on PSESP into conservation planning in China. Here, ecological niche modelling is used to project current and future habitat distributions of six PSESP in China under climate change scenarios and conservation planning software is applied to identify priority conservation areas (PCAs for these PSESP based on habitat distributions. These results were used to provide proposals for in-situ and ex-situ conservation measures directed at PSESP. It was found that annual precipitation was important for habitat distributions for all six PSESP (with the percentage contribution to habitat distributions ranging from 18.1 % to 74.9 % and non-climatic variables including soil and altitude have a large effect on habitat suitability of PSESP. Large quantities of PCAs occurred within some provincial regions for these six PSESP (e.g. Sichuan and Jilin for the PSESP Cathaya argyrophylla, Taxus cuspidata, Annamocarya sinensis and Madhuca pasquieri, indicating that these are likely to be appropriate areas for in-situ and ex-situ conservation measures directed at these PSESP. Those nature reserves with large quantities of PCAs were identified as promising sites for in-situ conservation measures of PSESP; such reserves include Yangzie and Dongdongtinghu for C. argyrophylla, Songhuajiangsanhu and Changbaishan for T. cuspidata and Shiwandashanshuiyuanlian for Tsoongiodendron odorum. These results suggest that existing seed banks and botanical gardens occurring within identified PCAs should allocate more resources and space to ex-situ conservation of PSESP. In addition, there should be additional botanical gardens established for ex-situ conservation of PSESP in PCAs outside existing nature reserves. To

  5. Biomarker of chronic cadmium exposure in a population residing in the vicinity of a zinc producing plant

    International Nuclear Information System (INIS)

    Bratveit, Magne; Mageroy, Nils; Gundersen, Hilde; Vahter, Marie; Moen, Bente E.

    2011-01-01

    to a zinc smelter. → Urinary cadmium did not differ between populations close to the plant and controls. → Positive correlation between cadmium and α1-microglobulin (ProteinHC) in urine. → No difference in ProteinHC between residents in polluted area and controls. → No indications of elevated cadmium exposure or kidney damage in polluted area.

  6. Influence of ambient and enhanced ultraviolet-B radiation on the plant growth and physiological properties in two contrasting populations of Hippophae rhamnoides

    International Nuclear Information System (INIS)

    Yang, Y.; Yao, Y.; He, H.

    2008-01-01

    Two contrasting sea buckthorn (Hippophae rhamnoides L.) populations from low and high altitude regions were employed to investigate the effects of prevailing and enhanced ultraviolet-B (UV-B) radiation on plant growth and physiological properties under a UVB-enhanced/exclusion system. The experimental design included three UV-B regimes, including excluded (-UVB), near-ambient (NA) and enhanced UV-B (+UVB) radiation. Compared with the control (-UVB), NA caused the formation of smaller but thicker plant leaves in both sea buckthorn populations, paralleled with significant increments of carotenoids and UV-absorbing compounds as well as improved water economy. NA also induced more biomass partition from shoot to root, but CO2 assimilation rate (A), photosynthetic area and biomass accumulation were unaffected. The low-altitude population seemed sensitive to +uvB, as indicated by the decreases in total biomass, A and ascorbic acid content (Asa, an antioxidant) compared with NA. However, little +UVB effect occurred on the high-altitude population, and we suggest that the higher tolerance of this population could be associated with its specific morphological and physiological characteristics, such as small but thick leaves and high-level of Asa content, as well as its greater physiological modification in response to NA, e.g., increases in protective compounds (carotenoids and UV-absorbing compounds) and improvement in water economy, in comparison to the low-altitude population, which form an effective adaptation strategy to enhanced UV-B stress

  7. Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

    Science.gov (United States)

    van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

  8. Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

    Directory of Open Access Journals (Sweden)

    Omer Kaynakli

    2011-06-01

    Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

  9. Proposal of guidelines for selecting optimum options in packagings and transportation systems of spent fuel

    International Nuclear Information System (INIS)

    Saegusa, T.; Abe, H.; Fukuda, S.

    1983-01-01

    Type and size of spent fuel shipping packagings and packaging transport ships in spent fuel transport system would have been determined separately in response to technical requirements etc. of reactor sites and reprocessing plants. However, since more and more spent fuel will be generated from world's nuclear power plants and will be transported much frequently to reprocessing plants or storage facilities, the current spent fuel transport system will have to be necessarily reexamined from the operational and economical aspects or an optimum transport system may have to be newly determined in the near future. In the literature, a variety of options are found, particularly of spent fuel packagings. This paper listed and classified options of spent fuel packagings and packaging transport ships in the transportation systems of spent fuel on the basis of literature surveys. These options were discussed from viewpoints of designers and users and compared in terms of transport efficiency. Finally, one way to determine an optimum transport system of spent fuel was indicated considering the total transport system in the light of safety, operational efficiency and economy

  10. How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products.

    Science.gov (United States)

    Hommen, Udo; Schmitt, Walter; Heine, Simon; Brock, Theo Cm; Duquesne, Sabine; Manson, Phil; Meregalli, Giovanna; Ochoa-Acuña, Hugo; van Vliet, Peter; Arts, Gertie

    2016-01-01

    This case study of the Society of Environmental Toxicology and Chemistry (SETAC) workshop MODELINK demonstrates the potential use of mechanistic effects models for macrophytes to extrapolate from effects of a plant protection product observed in laboratory tests to effects resulting from dynamic exposure on macrophyte populations in edge-of-field water bodies. A standard European Union (EU) risk assessment for an example herbicide based on macrophyte laboratory tests indicated risks for several exposure scenarios. Three of these scenarios are further analyzed using effect models for 2 aquatic macrophytes, the free-floating standard test species Lemna sp., and the sediment-rooted submerged additional standard test species Myriophyllum spicatum. Both models include a toxicokinetic (TK) part, describing uptake and elimination of the toxicant, a toxicodynamic (TD) part, describing the internal concentration-response function for growth inhibition, and a description of biomass growth as a function of environmental factors to allow simulating seasonal dynamics. The TK-TD models are calibrated and tested using laboratory tests, whereas the growth models were assumed to be fit for purpose based on comparisons of predictions with typical growth patterns observed in the field. For the risk assessment, biomass dynamics are predicted for the control situation and for several exposure levels. Based on specific protection goals for macrophytes, preliminary example decision criteria are suggested for evaluating the model outputs. The models refined the risk indicated by lower tier testing for 2 exposure scenarios, while confirming the risk associated for the third. Uncertainties related to the experimental and the modeling approaches and their application in the risk assessment are discussed. Based on this case study and the assumption that the models prove suitable for risk assessment once fully evaluated, we recommend that 1) ecological scenarios be developed that are also

  11. Effect of zinc and plant-population on the yield and yield components of maize (zea mays L.)

    International Nuclear Information System (INIS)

    Kakar, K.M.; Sadiq, S.A.; Tariq, M.

    2005-01-01

    A field experiment was conducted during 2001 to study the effect of two levels of zinc (0 and 5 kg Zn ha-J) and three plant-densities (60,000, 80,000 and 100,000 plants ha-J) on the performance of two varieties of maize Azam and Pahari and two hybrids N7989 and Babar, at Malakandher Farm of NWFP Agricultural University, Peshawar. Zinc at the rate of 5 kg ha-J increased the cob yield, grain yield and 1000-grain weight, while increase in plant-density significantly increased the number of grains cob-J, number of cob-plant-J, cob-yield, grain-yield and 1000-grain weight. Results revealed that the highest plant-density of 100,000 plant ha-J decreased the number of cobs plant-J, number of grains cob-J and 1000-grain weight. Maximum number of cobs plant-J (0.87), number of grains cob-J (313), cob yield (4602 kg ha-J), grain yield (4222 kg ha-J) and 1000-grain weight (249 g) were obtained with plant- density of 80,000 plant ha-J. The maximum grain-yield of 4333 kg ha-J was recorded in plots of hybrid variety N7989. (author)

  12. The Microbial Database for Danish wastewater treatment plants with nutrient removal (MiDas-DK) - a tool for understanding activated sludge population dynamics and community stability.

    Science.gov (United States)

    Mielczarek, A T; Saunders, A M; Larsen, P; Albertsen, M; Stevenson, M; Nielsen, J L; Nielsen, P H

    2013-01-01

    Since 2006 more than 50 Danish full-scale wastewater treatment plants with nutrient removal have been investigated in a project called 'The Microbial Database for Danish Activated Sludge Wastewater Treatment Plants with Nutrient Removal (MiDas-DK)'. Comprehensive sets of samples have been collected, analyzed and associated with extensive operational data from the plants. The community composition was analyzed by quantitative fluorescence in situ hybridization (FISH) supported by 16S rRNA amplicon sequencing and deep metagenomics. MiDas-DK has been a powerful tool to study the complex activated sludge ecosystems, and, besides many scientific articles on fundamental issues on mixed communities encompassing nitrifiers, denitrifiers, bacteria involved in P-removal, hydrolysis, fermentation, and foaming, the project has provided results that can be used to optimize the operation of full-scale plants and carry out trouble-shooting. A core microbial community has been defined comprising the majority of microorganisms present in the plants. Time series have been established, providing an overview of temporal variations in the different plants. Interestingly, although most microorganisms were present in all plants, there seemed to be plant-specific factors that controlled the population composition thereby keeping it unique in each plant over time. Statistical analyses of FISH and operational data revealed some correlations, but less than expected. MiDas-DK (www.midasdk.dk) will continue over the next years and we hope the approach can inspire others to make similar projects in other parts of the world to get a more comprehensive understanding of microbial communities in wastewater engineering.

  13. Determination of optimum filter in myocardial SPECT: A phantom study

    International Nuclear Information System (INIS)

    Takavar, A.; Shamsipour, Gh.; Sohrabi, M.; Eftekhari, M.

    2004-01-01

    Background: In myocardial perfusion SPECT images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. Filters greatly affect quality of nuclear medicine images. Materials and Methods: A phantom simulating heart left ventricle was built. About 1mCi of 99m Tc was injected into the phantom. Images was taken from this phantom. Some filters including Parzen, Hamming, Hanning, Butter worth and Gaussian were exerted on the phantom images. By defining some criteria such as contrast, signal to noise ratio, and defect size detectability, the best filter can be determined. Results: 0.325 Nyquist frequency and 0.5 nq was obtained as the optimum cut off frequencies respectively for hamming and handing filters. Order 11, cut off 0.45 Nq and order 20 cut off 0.5 Nq obtained optimum respectively for Butter worth and Gaussian filters. Conclusion: The optimum member of every filter's family was obtained

  14. Optimum Arrangement of Reactive Power Sources While Using Genetic Algori

    Directory of Open Access Journals (Sweden)

    A. M. Gashimov

    2010-01-01

    Full Text Available Reduction of total losses in distribution electricity supply network is considered as an important measure which serves for improvement of efficiency of electric power supply systems. This objective can be achieved by optimum distribution of reactive power sources in proper places of distribution electricity supply network. The proposed methodology is based on application of a genetic algorithm. Total expenses for installation of capacitor banks, their operation and also expenses related to electric power losses are considered as an efficiency function which is used for determination of places with optimum values of capacitor bank power. The methodology is the most efficient for selection of optimum places in the network where it is necessary to install capacitor banks with due account of their power control depending on a switched-on load value in the units.

  15. Optimum Combining for Rapidly Fading Channels in Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Sonia Furman

    2003-10-01

    Full Text Available Research and technology in wireless communication systems such as radar and cellular networks have successfully implemented alternative design approaches that utilize antenna array techniques such as optimum combining, to mitigate the degradation effects of multipath in rapid fading channels. In ad hoc networks, these methods have not yet been exploited primarily due to the complexity inherent in the network's architecture. With the high demand for improved signal link quality, devices configured with omnidirectional antennas can no longer meet the growing need for link quality and spectrum efficiency. This study takes an empirical approach to determine an optimum combining antenna array based on 3 variants of interelement spacing. For rapid fading channels, the simulation results show that the performance in the network of devices retrofitted with our antenna arrays consistently exceeded those with an omnidirectional antenna. Further, with the optimum combiner, the performance increased by over 60% compared to that of an omnidirectional antenna in a rapid fading channel.

  16. Optimum detection for extracting maximum information from symmetric qubit sets

    International Nuclear Information System (INIS)

    Mizuno, Jun; Fujiwara, Mikio; Sasaki, Masahide; Akiba, Makoto; Kawanishi, Tetsuya; Barnett, Stephen M.

    2002-01-01

    We demonstrate a class of optimum detection strategies for extracting the maximum information from sets of equiprobable real symmetric qubit states of a single photon. These optimum strategies have been predicted by Sasaki et al. [Phys. Rev. A 59, 3325 (1999)]. The peculiar aspect is that the detections with at least three outputs suffice for optimum extraction of information regardless of the number of signal elements. The cases of ternary (or trine), quinary, and septenary polarization signals are studied where a standard von Neumann detection (a projection onto a binary orthogonal basis) fails to access the maximum information. Our experiments demonstrate that it is possible with present technologies to attain about 96% of the theoretical limit

  17. Genetic differentiation among Maruca vitrata F. (Lepidoptera: Crambidae populations on cultivated cowpea and wild host plants: implications for insect resistance management and biological control strategies.

    Directory of Open Access Journals (Sweden)

    Tolulope A Agunbiade

    Full Text Available Maruca vitrata Fabricius (Lepidoptera: Crambidae is a polyphagous insect pest that feeds on a variety of leguminous plants in the tropics and subtropics. The contribution of host-associated genetic variation on population structure was investigated using analysis of mitochondrial cytochrome oxidase 1 (cox1 sequence and microsatellite marker data from M. vitrata collected from cultivated cowpea (Vigna unguiculata L. Walp., and alternative host plants Pueraria phaseoloides (Roxb. Benth. var. javanica (Benth. Baker, Loncocarpus sericeus (Poir, and Tephrosia candida (Roxb.. Analyses of microsatellite data revealed a significant global FST estimate of 0.05 (P≤0.001. The program STRUCTURE estimated 2 genotypic clusters (co-ancestries on the four host plants across 3 geographic locations, but little geographic variation was predicted among genotypes from different geographic locations using analysis of molecular variance (AMOVA; among group variation -0.68% or F-statistics (FSTLoc = -0.01; P = 0.62. These results were corroborated by mitochondrial haplotype data (φSTLoc = 0.05; P = 0.92. In contrast, genotypes obtained from different host plants showed low but significant levels of genetic variation (FSTHost = 0.04; P = 0.01, which accounted for 4.08% of the total genetic variation, but was not congruent with mitochondrial haplotype analyses (φSTHost = 0.06; P = 0.27. Variation among host plants at a location and host plants among locations showed no consistent evidence for M. vitrata population subdivision. These results suggest that host plants do not significantly influence the genetic structure of M. vitrata, and this has implications for biocontrol agent releases as well as insecticide resistance management (IRM for M. vitrata in West Africa.

  18. Determination of optimum oven cooking procedures for lean beef products

    OpenAIRE

    Rodas?Gonz?lez, Argenis; Larsen, Ivy L.; Uttaro, Bethany; Ju?rez, Manuel; Parslow, Joyce; Aalhus, Jennifer L.

    2015-01-01

    Abstract In order to determine optimum oven cooking procedures for lean beef, the effects of searing at 232 or 260?C for 0, 10, 20 or 30?min, and roasting at 160 or 135?C on semimembranosus (SM) and longissimus lumborum (LL) muscles were evaluated. In addition, the optimum determined cooking method (oven?seared for 10?min at 232?C and roasted at 135?C) was applied to SM roasts varying in weight from 0.5 to 2.5?kg. Mainly, SM muscles seared for 0 or 10?min at 232?C followed by roast at 135?C h...

  19. A first course in optimum design of yacht sails

    Science.gov (United States)

    Sugimoto, Takeshi

    1993-03-01

    The optimum sail geometry is analytically obtained for the case of maximizing the thrust under equality and inequality constraints on the lift and the heeling moment. A single mainsail is assumed to be set close-hauled in uniform wind and upright on the flat sea surface. The governing parameters are the mast height and the gap between the sail foot and the sea surface. The lifting line theory is applied to analyze the aerodynamic forces acting on a sail. The design method consists of the variational principle and a feasibility study. Almost triangular sails are found to be optimum. Their advantages are discussed.

  20. Generic Advertising Optimum Budget for Iran’s Milk Industry

    Directory of Open Access Journals (Sweden)

    H. Shahbazi

    2016-05-01

    Full Text Available Introduction One of the main targets of planners, decision makers and governments is increasing society health with promotion and production of suitable and healthy food. One of the basic commodities that have important role in satisfaction of required human food is milk. So, some part of government and producer healthy budget allocate to milk consumption promotion by using generic advertising. If effectiveness of advertising budget on profitability is more, producer will have more willing to spend for advertising. Determination of optimal generic advertising budget is one of important problem in managerial decision making in producing firm as well as increase in consumption and profit and decrease in wasting and non-optimality of budget. Materials and Methods: In this study, optimal generic advertising budget intensity index (advertising budget share of production cost was estimated under two different scenarios by using equilibrium replacement model. In equilibrium replacement model, producer surplus are maximized in respect to generic advertising in retail level. According to market where two levels of farm and processing before retail exist and there is trade in farm and retail level, we present different models. Fixed and variable proportion hypothesis is another one. Finally, eight relations are presented for determination of milk generic advertising optimum budget. So, we use data from several resources such as previous studies, national (Iran Static center and international institute (Fao formal data and own estimation. Because there are several estimations in previous studies, we identify some scenarios (in two general scenarios for calculation of milk generic advertising optimum budget. Results and Discussion: Estimation of milk generic advertising optimum budget in scenario 1 shows that in case of one market level, fixed supplies and no trade, optimum budget is 0.4672539 percent. In case of one market level and no trade, optimum

  1. Optimum position of isolators within erbium-doped fibers

    DEFF Research Database (Denmark)

    Lumholt, Ole; Schüsler, Kim; Bjarklev, Anders Overgaard

    1992-01-01

    An isolator is used as an amplified spontaneous emission suppressing component within an erbium-doped fiber. The optimum isolator placement is both experimentally and theoretically determined and found to be slightly dependent upon pump power. Improvements of 4 dB in gain and 2 dB in noise figure...... are measured for the optimum isolator location at 25% of the fiber length when the fiber is pumped with 60 mW of pump power at 1.48 μm...

  2. Influence of plant species and environmental conditions on epiphytic and endophytic pink-pigmented facultative methylotrophic bacterial populations associated with field-grown rice cultivars.

    Science.gov (United States)

    Madhaiyan, Munusamy; Poonguzhali, Selvaraj; Sa, Tongmin

    2007-10-01

    The total methylotrophic population associated with rice plants from different cultivars was enumerated at three different stages: vegetative, flowering, and harvesting. The bacterial population in the leaf, rhizosphere soil, endophytic in the stem and roots, and epiphytic in the florets and grains were determined from four rice cultivars, Il-mi, Nam-pyeoung, O-dae, and Dong-jin, sampled from three different field sites. The methylotrophic bacteria isolated on AMS media containing 0.5% methanol as the sole carbon source uniformly showed three distinct morphologies, which were recorded as separate groups and their distribution among the various samples was determined using the ecophysiological index. The growth stage at the time of sampling had a more significant effect on the methylotrophic population and their distribution than the field site or cultivar. A similar effect was also observed for the PPFMs, where their population in different plant parts increased from V10 to R4 and then decreased towards stage R9. A canonical discriminant analysis of the PPFM population from different parts of rice showed clear variations among the cultivars, sampled sites, and growth stages, although the variations were more prominent among the growth stages.

  3. Model-based scenario planning to develop climate change adaptation strategies for rare plant populations in grassland reserves

    Science.gov (United States)

    Laura Phillips-Mao; Susan M. Galatowitsch; Stephanie A. Snyder; Robert G. Haight

    2016-01-01

    Incorporating climate change into conservation decision-making at site and population scales is challenging due to uncertainties associated with localized climate change impacts and population responses to multiple interacting impacts and adaptation strategies. We explore the use of spatially explicit population models to facilitate scenario analysis, a conservation...

  4. Ecological consequences, genetic and chemical variations in fragmented populations of a medicinal plant, justicia adhatoda and implications for its conservation

    International Nuclear Information System (INIS)

    Gilani, S.A.; Watanabe, K.N.; Fujii, Y.; Shinwari, Z.K.

    2011-01-01

    Justicia adhatoda from Kohat Plateau was selected for genetic diversity studies, due to its fragmented habitat, importance in traditional and pharmaceutical medicine and a lack of population structure studies. We had two hypotheses: that habitat loss posed a greater threat to populations than loss of genetic diversity, and that chemical diversity would be higher among different populations than within populations. Genetic diversity within and among populations was evaluated using PBA (P450 based analogue) markers. AMOVA analysis revealed that there was higher genetic diversity within populations (90%) than among populations (10%). No genetic drift was observed, i.e., genetic diversity within populations was maintained despite fewer numbers of individuals in fragmented populations. Surveys of J. adhatoda populations revealed that they were growing in harsh conditions and were imperiled due to extensive harvesting for commercial and domestic purposes. Chemical diversity was evaluated by GC-MS (Gas Chromatograph-Mass Spectrometry) analysis of 90% methanol and 1:2 chloroform:methanol extracts. GC-MS analysis of both the extracts showed nine and 18 chemical compounds, respectively, with higher chemical variations among populations. It is therefore recommended that efforts for the conservation of severely fragmented populations of J. adhatoda must be carried out along with sustainable harvesting. (author)

  5. Assessment of reproductive capacity of seeds sampled from natural populations of plants from a territory contaminated with radionuclides and heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Vakhusheva, O.; Evseeva, T. [Institute of biology Komi SC Ural Branch of RAS (Russian Federation)

    2014-07-01

    Plants are an essential component of any ecosystem and are permanently exposed to soil contamination. Therefore, they are widely used for characterization of ecological situation of the territory. Located at the base of the food chain, plants are exposed to toxic agents before the organisms at higher trophic levels. Kirovo-Chepetsk chemical plant (Kirov, Russia) is one of the biggest chemical enterprises in Europe. Vascular plant communities from surrounding area are exposed to industrial wastes, including uranium production wastes from 1938. The aim of this work was to estimate reproductive capacity of Urtica dioica L., Cirsium setosum (Willd.) Bess and Filipendula ulmaria (L.) Maxim - natural populations inhabiting the chemical plant industrial zone. The plant species studied are common for the meadow communities of south taiga zone, and are characterized by high seed yield and living in wide range of ecological conditions. Plant seeds were collected from two experimental sites with different soil contamination levels, located in the vicinity of the Kirovo-Chepetsk chemical plant, as well as from the reference site, in 2011 and 2012. Soil specific activities of {sup 137}Cs and {sup 90}Sr and concentrations of Ni, Pb, Cd, Zn, Hg and Cu were measured and ecological criteria of the radioactive (C{sub r}) and chemical (C{sub c}) contamination of the soil cover were calculated. Seeds germination, germinative energy and seedling survival rate were used for assessing reproductive capacity. Urtica dioicawas found to be the most sensitive among plant species studied. Germination of seeds from contaminated sites was significantly lower compared with the reference values. Exponential relationship was found between the levels of soil radioactive contamination and seeds germination (R{sup 2}=0.8, p<0.001). Germination of Cirsium setosum seeds, sampled from contaminated sites, exceeded the values obtained for the reference plant population and was linearly dependent (R{sup 2

  6. Ecology of Meimuna mongolica (Hemiptera: Cicadidae) Nymphs: Instars, Morphological Variation, Vertical Distribution and Population Density, Host-Plant Selection, and Emergence Phenology

    Science.gov (United States)

    Li, Qinglong; Yang, Mingsheng; Liu, Yunxiang; Wei, Cong

    2015-01-01

    The cicada Meimuna mongolica (Distant) (Hemiptera: Cicadidae) is one of the most important pests of economic forest in Guanzhong Plain of Shaanxi Province, China. Information about ecological characteristics and some sustainable control measures of this species is urgently required for its control. In this study, nymphal instars, morphological variation, vertical distribution, and population density in soil, and emergence phenology of nymphs of M. mongolica on three main host plants (Pinus tabuliformis Carr., Populus tomentosa Carr., and Pyrus xerophila Yü) were studied, based on combined morphological and molecular identification, investigation of the first-instar nymphs hatched from eggs and others excavated from soil, and investigation of exuviae in the adult emergence period. Five nymphal instars of M. mongolica were redetermined according to the distribution plots of the head capsule widths of the nymphs. Nymphs of third and fourth instars showed morphological variation, which is closely related to host-plant association. The mean densities of nymphs in soil under the three host plants were significantly different, indicating a distinct host preference. The nymphs could extend their distribution from the 0–10 cm soil layer to the 51–60 cm soil layer underground but not beyond 60 cm soil layer under all the three host plants. The 21–30 cm soil layer under all the three host plants has the highest nymphal population density. The sex ratio of the entire population was nearly 50:50, but males dominated in the early half of the duration of the emergence. These ecological characteristics of M. mongolica could provide important information for sustainable control measures.

  7. Proof of radiation exposure in the vicinity of Kruemmel power plant by chromosomal analysis of the population and by enhanced environmental radioactivity

    International Nuclear Information System (INIS)

    Dannheim, B.; Heimers, A.; Schmitz-Feuerhake, I.; Schroeder, H.

    2001-01-01

    The leukaemia cluster in the proximity of the German boiling water reactor Kruemmel was detected by a local physician. 9 cases in children were registered in the period 1990-1996 which corresponds to 5.6 fold increase in the 5 km region around the plant. An incidence study conducted between 1984-93 showed an elevated rate of leukaemias also in adults. Because the supervising ministry had attested undisturbed operation of the plant and no conspiceous radioactivity had been noticed at that time, we started an independent investigation. Radiation exposures during the operation of the plant were proven by chromosome aberration studies in the population and by analyses of the environmental radioactivity. (orig.) [de

  8. High and uneven levels of 45S rDNA site-number variation across wild populations of a diploid plant genus (Anacyclus, Asteraceae).

    Science.gov (United States)

    Rosato, Marcela; Álvarez, Inés; Nieto Feliner, Gonzalo; Rosselló, Josep A

    2017-01-01

    The nuclear genome harbours hundreds to several thousand copies of ribosomal DNA. Despite their essential role in cellular ribogenesis few studies have addressed intrapopulation, interpopulation and interspecific levels of rDNA variability in wild plants. Some studies have assessed the extent of rDNA variation at the sequence and copy-number level with large sampling in several species. However, comparable studies on rDNA site number variation in plants, assessed with extensive hierarchical sampling at several levels (individuals, populations, species) are lacking. In exploring the possible causes for ribosomal loci dynamism, we have used the diploid genus Anacyclus (Asteraceae) as a suitable system to examine the evolution of ribosomal loci. To this end, the number and chromosomal position of 45S rDNA sites have been determined in 196 individuals from 47 populations in all Anacyclus species using FISH. The 45S rDNA site-number has been assessed in a significant sample of seed plants, which usually exhibit rather consistent features, except for polyploid plants. In contrast, the level of rDNA site-number variation detected in Anacyclus is outstanding in the context of angiosperms particularly regarding populations of the same species. The number of 45S rDNA sites ranged from four to 11, accounting for 14 karyological ribosomal phenotypes. Our results are not even across species and geographical areas, and show that there is no clear association between the number of 45S rDNA loci and the life cycle in Anacyclus. A single rDNA phenotype was detected in several species, but a more complex pattern that included intra-specific and intra-population polymorphisms was recorded in A. homogamos, A. clavatus and A. valentinus, three weedy species showing large and overlapping distribution ranges. It is likely that part of the cytogenetic changes and inferred dynamism found in these species have been triggered by genomic rearrangements resulting from contemporary

  9. Determination of Optimum Moisture Content of Palm Nut Cracking ...

    African Journals Online (AJOL)

    USER

    ABSTRACT: After processing the palm fruit for oil, the nut is usually dried in order to loosen the kernel from the shell. The drying is necessary to enhance the release of whole kernel when the nut is cracked. A study was carried out to determine the optimum moisture content of nuts for high yield of whole kernels during ...

  10. Optimum tilt angle and orientation for solar collectors in Syria

    International Nuclear Information System (INIS)

    Skeiker, Kamal

    2009-01-01

    One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector in the main Syrian zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of approximately 30% more than the case of a solar collector fixed on a horizontal surface.

  11. Analytical Solution for Optimum Design of Furrow Irrigation Systems

    Science.gov (United States)

    Kiwan, M. E.

    1996-05-01

    An analytical solution for the optimum design of furrow irrigation systems is derived. The non-linear calculus optimization method is used to formulate a general form for designing the optimum system elements under circumstances of maximizing the water application efficiency of the system during irrigation. Different system bases and constraints are considered in the solution. A full irrigation water depth is considered to be achieved at the tail of the furrow line. The solution is based on neglecting the recession and depletion times after off-irrigation. This assumption is valid in the case of open-end (free gradient) furrow systems rather than closed-end (closed dike) systems. Illustrative examples for different systems are presented and the results are compared with the output obtained using an iterative numerical solution method. The final derived solution is expressed as a function of the furrow length ratio (the furrow length to the water travelling distance). The function of water travelling developed by Reddy et al. is considered for reaching the optimum solution. As practical results from the study, the optimum furrow elements for free gradient systems can be estimated to achieve the maximum application efficiency, i.e. furrow length, water inflow rate and cutoff irrigation time.

  12. Optimum position for wells producing at constant wellbore pressure

    Energy Technology Data Exchange (ETDEWEB)

    Camacho-Velazquez, R.; Rodriguez de la Garza, F. [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico); Galindo-Nava, A. [Inst. Mexicanos del Petroleo, Mexico City (Mexico)]|[Univ. Nacional de Mexico, Mexico City (Mexico); Prats, M.

    1994-12-31

    This paper deals with the determination of the optimum position of several wells, producing at constant different wellbore pressures from a two-dimensional closed-boundary reservoirs, to maximize the cumulative production or the total flow rate. To achieve this objective they authors use an improved version of the analytical solution recently proposed by Rodriguez and Cinco-Ley and an optimization algorithm based on a quasi-Newton procedure with line search. At each iteration the algorithm approximates the negative of the objective function by a cuadratic relation derived from a Taylor series. The improvement of rodriguez and Cinco`s solution is attained in four ways. First, an approximation is obtained, which works better at earlier times (before the boundary dominated period starts) than the previous solution. Second, the infinite sums that are present in the solution are expressed in a condensed form, which is relevant for reducing the computer time when the optimization algorithm is used. Third, the solution is modified to take into account the possibility of having wells starting to produce at different times. This point allows them to deal with the problem of getting the optimum position for an infill drilling program. Last, the solution is extended to include the possibility of changing the value of wellbore pressure or being able to stimulate any of the wells at any time. When the wells are producing at different wellbore pressures it is found that the optimum position is a function of time, otherwise the optimum position is fixed.

  13. Optimum Onager: The Classical Mechanics of a Classical Siege Engine

    Science.gov (United States)

    Denny, Mark

    2009-01-01

    The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this…

  14. The effects of physical and chemical changes on the optimum ...

    African Journals Online (AJOL)

    The aim of this study was to determine physical and chemical changes during fruit development and their relationship with optimum harvest maturity for Bacon, Fuerte and Zutano avocado cultivars grown under Dörtyol ecological condition. Fruits cv. Bacon, Fuerte and Zutano were obtained trees grafted on seedlings and ...

  15. Applied orthogonal experiment design for the optimum microwave ...

    African Journals Online (AJOL)

    An experiment on polysaccharides from Rhodiolae Radix (PRR) extraction was carried out using microwave-assisted extraction (MAE) method with an objective to establishing the optimum MAE conditions of PRR. Single factor experiments were performed to determine the appropriate range of extraction conditions, and the ...

  16. Optimum geometry for torque ripple minimization of switched reluctance motors

    NARCIS (Netherlands)

    Sahin, F.; Ertan, H.B.; Leblebicioglu, K.

    2000-01-01

    For switched reluctance motors, one of the major problems is torque ripple which causes increased undesirable acoustic noise and possibly speed ripple. This paper describes an approach to determine optimum magnetic circuit parameters to minimize low speed torque ripple for such motors. The

  17. METHODS FOR DETERMINATION OF THE OPTIMUM EXPLOSIVES IN DIFFERENT ROCKS

    Directory of Open Access Journals (Sweden)

    Josip Krsnik

    1989-12-01

    Full Text Available The most appropriate explosives required for blasting of the particular types of rocks were established by test blasting method with linear burden increase. By the same method the optimum magnitudes of deep-holes blasting were established (the paper is published in Croatian.

  18. Applicability Problem in Optimum Reinforced Concrete Structures Design

    Directory of Open Access Journals (Sweden)

    Ashara Assedeq

    2016-01-01

    Full Text Available Optimum reinforced concrete structures design is very complex problem, not only considering exactness of calculus but also because of questionable applicability of existing methods in practice. This paper presents the main theoretical mathematical and physical features of the problem formulation as well as the review and analysis of existing methods and solutions considering their exactness and applicability.

  19. Is there an optimum level for renewable energy?

    International Nuclear Information System (INIS)

    Moriarty, Patrick; Honnery, Damon

    2011-01-01

    Because continued heavy use of fossil fuel will lead to both global climate change and resource depletion of easily accessible fuels, many researchers advocate a rapid transition to renewable energy (RE) sources. In this paper we examine whether RE can provide anywhere near the levels of primary energy forecast by various official organisations in a business-as-usual world. We find that the energy costs of energy will rise in a non-linear manner as total annual primary RE output increases. In addition, increasing levels of RE will lead to increasing levels of ecosystem maintenance energy costs per unit of primary energy output. The result is that there is an optimum level of primary energy output, in the sense that the sustainable level of energy available to the economy is maximised at that level. We further argue that this optimum occurs at levels well below the energy consumption forecasts for a few decades hence. - Highlights: → We need to shift to renewable energy for climate change and fuel depletion reasons. → We examine whether renewable energy can provide the primary energy levels forecast. → The energy costs of energy rise non-linearly with renewable energy output. → There is thus an optimum level of primary energy output. → This optimum occurs at levels well below future official energy use forecasts.

  20. How stem defects affect the capability of optimum bucking method?

    Directory of Open Access Journals (Sweden)

    Abdullah Emin Akay

    2015-07-01

    Full Text Available In forest harvesting activities, computer-assisted optimum bucking method increases the economic value of harvested trees. The bucking decision highly depends on the log quality grades which mainly vary with the surface characteristics such as stem defects and form of the stems. In this study, the effects of stem defects on optimum bucking method was investigated by comparing bucking applications which were conducted during the logging operations in two different Brutian Pine (Pinus brutia Ten stands. In the applications, the first stand contained the stems with relatively more stem defects than that of the stems in the second stand. The average number of defects per log for sample trees in the first and the second stand was recorded as 3.64 and 2.70, respectively. The results indicated that optimum bucking method increased the average economic value of harvested trees by 15.45% and 8.26 % in the stands, respectively. Therefore, the computer-assisted optimum bucking method potentially provides better results than that of traditional bucking method especially for the harvested trees with more stem defects.

  1. Optimum length of finned pipe for waste heat recovery

    International Nuclear Information System (INIS)

    Soeylemez, M.S.

    2008-01-01

    A thermoeconomic feasibility analysis is presented yielding a simple algebraic optimization formula for estimating the optimum length of a finned pipe that is used for waste heat recovery. A simple economic optimization method is used in the present study by combining it with an integrated overall heat balance method based on fin effectiveness for calculating the maximum savings from a waste heat recovery system

  2. The Optimum Conditions of Foreign Languages in Primary Education

    Science.gov (United States)

    Giannikas, Christina Nicole

    2014-01-01

    The aim of the paper is to review the primary language learning situation in Europe and shed light on the benefits it carries. Early language learning is the biggest policy development in education and has developed in rapid speed over the past 30 years; this article considers the effects and advantages of the optimum condition of an early start,…

  3. Improved optimum condition for recovery and measurement of 210 ...

    African Journals Online (AJOL)

    The aim of this study was to determine the optimum conditions for deposition of 210Po and evaluate the accuracy and precision of the results for its determination in environmental samples. To improve the technique for measurement of polonium-210(210Po) in environmental samples. The optimization of five factors (volume ...

  4. Dietary energy level for optimum productivity and carcass ...

    African Journals Online (AJOL)

    user

    2013-08-05

    Aug 5, 2013 ... optimum weights at dietary energy levels of 13.81, 13.23, 13.43 and ... Tadelle & Ogle (2000) reported that energy requirement of ..... The authors would like to acknowledge the National Research Foundation (NRF) and VLIR ...

  5. Optimum dietary protein requirement of genetically male tilapia ...

    African Journals Online (AJOL)

    The study was conducted to investigate the optimum dietary protein level needed for growing genetically male tilapia, Oreochromis niloticus. Diets containing crude protein levels 40, 42.5, 45, 47.5 and 50% were formulated and tried in triplicates. Test diets were fed to 20 fish/1m3 floating hapa at 5% of fish body weight daily ...

  6. Optimum development temperature and duration for nuclear plate

    International Nuclear Information System (INIS)

    Nagoshi, Chieko.

    1975-01-01

    Sakura 100 μm thick nuclear plates have been employed to determine optimum temperature and duration of the Amidol developer for low energy protons (Ep 0 C were tried for periods of 15--35 min. For Ep 0 C and for development time less than 30 min. (auth.)

  7. Optimum workforce-size model using dynamic programming approach

    African Journals Online (AJOL)

    This paper presents an optimum workforce-size model which determines the minimum number of excess workers (overstaffing) as well as the minimum total recruitment cost during a specified planning horizon. The model is an extension of other existing dynamic programming models for manpower planning in the sense ...

  8. Dietary energy level for optimum productivity and carcass ...

    African Journals Online (AJOL)

    A study was conducted to determine dietary energy levels for optimum productivity and carcass characteristics of indigenous Venda chickens raised in closed confinement. Four dietary treatments were considered in the first phase (1 to 7 weeks) on two hundred day-old unsexed indigenous Venda chicks indicated as EVS1, ...

  9. Procedure for determining the optimum rate of increasing shaft depth

    Energy Technology Data Exchange (ETDEWEB)

    Durov, E.M.

    1983-03-01

    Presented is an economic analysis of increasing shaft depth during mine modernization. Investigations carried out by the Yuzhgiproshakht Institute are analyzed. The investigations are aimed at determining the optimum shaft sinking rate (the rate which reduces investment to the minimum). The following factors are considered: coal output of a mine (0.9, 1.2, 1.5 and 1.8 Mt/year), depth at which the new mining level is situated (600, 800, 1200, 1400 and 1600 m), four schemes of increasing depth of 2 central shafts (rock hoisting to ground surface, rock hoisting to the existing level, rock haulage to the developed level, rock haulage to the level being developed using a large diameter borehole drilled from the new level to the shaft bottom and enlarged from shaft bottom to the new level), shaft sinking rate (10, 20, 30, 40, 50 and 60 m/month), range of increasing shaft depth (the difference between depth of the shaft before and after increasing its depth by 100, 200, 300 and 400 m). Comparative evaluations show that the optimum shaft sinking rate depends on the scheme for rock hoisting (one of 4 analyzed), range of increasing shaft depth and gas content in coal seams. The optimum shaft sinking rate ranges from 20 to 40 m/month in coal mines with low methane content and from 20 to 30 m/month in gassy coal mines. The planned coal output of a mine does not influence the optimum shaft sinking rate.

  10. Deuterium–tritium catalytic reaction in fast ignition: Optimum ...

    Indian Academy of Sciences (India)

    proton beam, the corresponding optimum interval values are proton average energy 3 ... contributions, into the study of the ignition and burn dynamics in a fast ignition frame- ..... choice of proton beam energy would fall in 3 ≤ Ep ≤ 10 MeV.

  11. The Effect of Organic Fertilizers and Flowering Plants on Sheet-Web and Wolf Spider Populations (Araneae: Lycosidae and Linyphiidae) and Its Importance for Pest Control.

    Science.gov (United States)

    El-Nabawy, El-Said M; Tsuda, Katsuo; Sakamaki, Yositaka; Oda, Asahi; Ushijima, Yurie

    2016-01-01

    The main goal of this study was to identify the treatment that increases the populations of spiders, which are effective predators in agroecosystems. In 2013 and 2014 the experimental eggplant (Solanum melongena L.) field was two different treatments, organic fertilizers and chemical fertilizer treatment, and in 2014 we surrounded organic fertilizer plots with the flowering plants mealy cup sage (Salvia farinacea Benth.), spearmint (Mentha spicata L.), and basil (Ocimum basilicum L.). Analysis using repeated measures ANOVA revealed significant influences of fertilizer type on the numbers of linyphiid spiders and Collembola in 2013. In 2014, the numbers of Collembola, thrips, and lycosid and linyphiid spider were higher in organic fertilizer with flowering plants treatment comparing with the chemical fertilizer treatment. Moreover, the numbers of Henosepilachna vigintioctopunctata (F.) were significantly lower in the organic fertilizer with flowering plants treatment than in chemical fertilizers treatment. Finally, we expect that Thysanoptera and Collembola were important alternative prey for linyphiid and lycosid spiders and the use of organic fertilizer and flowering plants enhanced the density of these spiders, and may increase their effectiveness in suppressing the populations of H. vigintioctopunctata (F.). © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  12. Morphological, Phenological And Agronomical Characterisation Of Variability Among Common Bean (Phaseolus Vulgaris L. Local Populations From The National Centre For Plant Genetic Resources: Polish Genebank

    Directory of Open Access Journals (Sweden)

    Boros Lech

    2014-12-01

    Full Text Available The main purpose of this work was to analyse the morphological, phenological and agronomical variability among common bean local populations from The National Centre for Plant Genetic Resources, Polish Genebank, in order to know the relation among them, and to identify potentially useful accessions for future production and breeding. A considerable genotypic variation for number of seeds per plant, number of pods per plant and weight of seeds per plant were found. Studied bean accessions differed significantly in terms of thousand seeds weight (TSW as well as severity of bacterial halo blight and anthracnose, the major bean diseases. The lowest genotypic diversity was found for the percentage of protein in the seeds, the length of the vegetation period and lodging. The cluster analysis allowed identification of five groups of bean accessions. Genotypes from the first cluster (POLPOD 98-77, KOS 002 and Raba cv. and from the second cluster (WUKR 06-573a, KRA 4, WUKR 06-0534 together with Prosna cv. are of the highest usefulness for breeding purposes. There was no grouping of local populations depending on region of origin.

  13. Thermodynamic analysis of PBMR plant

    International Nuclear Information System (INIS)

    Sen, S.; Kadiroglu, O.K.

    2002-01-01

    The thermodynamic analysis of a PBMR is presented for various pressures and temperatures values. The design parameters of the components of the power plant are calculated and an optimum cycle for the maximum thermal efficiency is sought for. (author)

  14. Optimum design for pipe-support allocation against seismic loading

    International Nuclear Information System (INIS)

    Hara, Fumio; Iwasaki, Akira

    1996-01-01

    This paper deals with the optimum design methodology of a piping system subjected to a seismic design loading to reduce its dynamic response by selecting the location of pipe supports and whereby reducing the number of pipe supports to be used. The author employs the Genetic Algorithm for obtaining a reasonably optimum solution of the pipe support location, support capacity and number of supports. The design condition specified by the support location, support capacity and the number of supports to be used is encored by an integer number string for each of the support allocation candidates and they prepare many strings for expressing various kinds of pipe-support allocation state. Corresponding to each string, the authors evaluate the seismic response of the piping system to the design seismic excitation and apply the Genetic Algorithm to select the next generation candidates of support allocation to improve the seismic design performance specified by a weighted linear combination of seismic response magnitude, support capacity and the number of supports needed. Continuing this selection process, they find a reasonably optimum solution to the seismic design problem. They examine the feasibility of this optimum design method by investigating the optimum solution for 5, 7 and 10 degree-of-freedom models of piping system, and find that this method can offer one a theoretically feasible solution to the problem. They will be, thus, liberated from the severe uncertainty of damping value when the pipe support guaranties the design capacity of damping. Finally, they discuss the usefulness of the Genetic Algorithm for the seismic design problem of piping systems and some sensitive points when it will be applied to actual design problems

  15. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

    Directory of Open Access Journals (Sweden)

    Catherine J. Collier

    2017-08-01

    Full Text Available Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri. To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average. This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature. The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C and H. uninervis (33°C, but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

  16. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

    Science.gov (United States)

    Collier, Catherine J; Ow, Yan X; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L; O'Brien, Katherine R; Hrebien, Victoria; Adams, Matthew P

    2017-01-01

    Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species ( Cymodocea serrulata, Halodule uninervis , and Zostera muelleri ). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum ( T opt ) for gross photosynthesis of Z. muelleri , which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The T opt for photosynthesis of the tropical species, H. uninervis and C. serrulata , was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature ( T opt varied by 1°C in C. serrulata and 2°C in H. uninervis , and the variation did not follow changes in ambient water temperature). The T opt for gross photosynthesis were higher than T opt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis ( 33°C), but remained unchanged at 35°C in C. serrulata . Both estimated plant net productivity and T opt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

  17. Optimum strata boundaries and sample sizes in health surveys using auxiliary variables.

    Science.gov (United States)

    Reddy, Karuna Garan; Khan, Mohammad G M; Khan, Sabiha

    2018-01-01

    Using convenient stratification criteria such as geographical regions or other natural conditions like age, gender, etc., is not beneficial in order to maximize the precision of the estimates of variables of interest. Thus, one has to look for an efficient stratification design to divide the whole population into homogeneous strata that achieves higher precision in the estimation. In this paper, a procedure for determining Optimum Stratum Boundaries (OSB) and Optimum Sample Sizes (OSS) for each stratum of a variable of interest in health surveys is developed. The determination of OSB and OSS based on the study variable is not feasible in practice since the study variable is not available prior to the survey. Since many variables in health surveys are generally skewed, the proposed technique considers the readily-available auxiliary variables to determine the OSB and OSS. This stratification problem is formulated into a Mathematical Programming Problem (MPP) that seeks minimization of the variance of the estimated population parameter under Neyman allocation. It is then solved for the OSB by using a dynamic programming (DP) technique. A numerical example with a real data set of a population, aiming to estimate the Haemoglobin content in women in a national Iron Deficiency Anaemia survey, is presented to illustrate the procedure developed in this paper. Upon comparisons with other methods available in literature, results reveal that the proposed approach yields a substantial gain in efficiency over the other methods. A simulation study also reveals similar results.

  18. Optimum electron temperature and density for short-wavelength plasma-lasing from nickel-like ions

    International Nuclear Information System (INIS)

    Masoudnia, Leili; Bleiner, Davide

    2014-01-01

    Soft X-ray lasing across a Ni-like plasma gain-medium requires optimum electron temperature and density for attaining to the Ni-like ion stage and for population inversion in the 3d 9 4d 1 (J=0)→3d 9 4p 1 (J=1) laser transition. Various scaling laws, function of operating parameters, were compared with respect to their predictions for optimum temperatures and densities. It is shown that the widely adopted local thermodynamic equilibrium (LTE) model underestimates the optimum plasma-lasing conditions. On the other hand, non-LTE models, especially when complemented with dielectronic recombination, provided accurate prediction of the optimum plasma-lasing conditions. It is further shown that, for targets with Z equal or greater than the rare-earth elements (e.g. Sm), the optimum electron density for plasma-lasing is not accessible for pump-pulses at λ=1ω=1μm. This observation explains a fundamental difficulty in saturating the wavelength of plasma-based X-ray lasers below 6.8 nm, unless using 2ω pumping

  19. Cholesterol lowering effect of a soy drink enriched with plant sterols in a French population with moderate hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Bard Jean-Marie

    2008-10-01

    Full Text Available Abstract Background Plant sterols are an established non-pharmacological means to reduce total and LDL blood cholesterol concentrations and are therefore recommended for cholesterol management by worldwide-renown health care institutions. Their efficacy has been proven in many types of foods with the majority of trials conducted in spreads or dairy products. As an alternative to dairy products, soy based foods are common throughout the world. Yet, there is little evidence supporting the efficacy of plant sterols in soy-based foods. The objective of this study was to investigate the effect of a soy drink enriched with plant sterols on blood lipid profiles in moderately hypercholesterolemic subjects. Methods In a randomized, placebo-controlled double-blind mono-centric study, 50 subjects were assigned to 200 ml of soy drink either enriched with 2.6 g plant sterol esters (1.6 g/d free plant sterol equivalents or without plant sterols (control for 8 weeks. Subjects were instructed to maintain stable diet pattern and physical activity. Plasma concentrations of lipids were measured at initial visit, after 4 weeks and after 8 weeks. The primary measurement was the change in LDL cholesterol (LDL-C. Secondary measurements were changes in total cholesterol (TC, non-HDL cholesterol (non-HDL-C, HDL cholesterol (HDL-C and triglycerides. Results Regular consumption of the soy drink enriched with plant sterols for 8 weeks significantly reduced LDL- C by 0.29 mmol/l or 7% compared to baseline (p 96%, and products were well tolerated. Conclusion Daily consumption of a plant sterol-enriched soy drink significantly decreased total, non-HDL and LDL cholesterol and is therefore an interesting and convenient aid in managing mild to moderate hypercholesterolemia.

  20. Gene flow and population subdivision in a pantropical plant with sea-drifted seeds Hibiscus tiliaceus and its allied species: evidence from microsatellite analyses.

    Science.gov (United States)

    Takayama, Koji; Tateishi, Yoichi; Murata, Jin; Kajita, Tadashi

    2008-06-01

    The genetic differentiation and structure of Hibiscus tiliaceus, a pantropical plant with sea-drifted seeds, and four allied species were studied using six microsatellite markers. A low level of genetic differentiation was observed among H. tiliaceus populations in the Pacific and Indian Ocean regions, similar to the results of a previous chloroplast DNA (cpDNA) study. Frequent gene flow by long-distance seed dispersal is responsible for species integration of H. tiliaceus in the wide distribution range. On the other hand, highly differentiated populations of H. tiliaceus were detected in West Africa, as well as of Hibiscus pernambucensis in southern Brazil. In the former populations, the African continent may be a geographical barrier that prevents gene flow by sea-drifted seeds. In the latter populations, although there are no known land barriers, the bifurcating South Equatorial Current at the north-eastern horn of Brazil can be a potential barrier to gene flow and may promote the genetic differentiation of these populations. Our results also suggest clear species segregation between H. tiliaceus and H. pernambucensis, which confirms the introgression scenario between these two species that was suggested by a previous cpDNA study. Our results also provide good evidence for recent transatlantic long-distance seed dispersal by sea current. Despite the distinct geographical structure observed in the cpDNA haplotypes, a low level of genetic differentiation was found between Pacific and Atlantic populations of H. pernambucensis, which could be caused by transisthmian gene flow.

  1. Genetic Diversity and Demographic History of Wild and Cultivated/Naturalised Plant Populations: Evidence from Dalmatian Sage (Salvia officinalis L., Lamiaceae)

    Science.gov (United States)

    Rešetnik, Ivana; Baričevič, Dea; Batîr Rusu, Diana; Carović-Stanko, Klaudija; Chatzopoulou, Paschalina; Dajić-Stevanović, Zora; Gonceariuc, Maria; Grdiša, Martina; Greguraš, Danijela; Ibraliu, Alban; Jug-Dujaković, Marija; Krasniqi, Elez; Liber, Zlatko; Murtić, Senad; Pećanac, Dragana; Radosavljević, Ivan; Stefkov, Gjoshe; Stešević, Danijela; Šoštarić, Ivan; Šatović, Zlatko

    2016-01-01

    Dalmatian sage (Salvia officinalis L., Lamiaceae) is a well-known aromatic and medicinal Mediterranean plant that is native in coastal regions of the western Balkan and southern Apennine Peninsulas and is commonly cultivated worldwide. It is widely used in the food, pharmaceutical and cosmetic industries. Knowledge of its genetic diversity and spatiotemporal patterns is important for plant breeding programmes and conservation. We used eight microsatellite markers to investigate evolutionary history of indigenous populations as well as genetic diversity and structure within and among indigenous and cultivated/naturalised populations distributed across the Balkan Peninsula. The results showed a clear separation between the indigenous and cultivated/naturalised groups, with the cultivated material originating from one restricted geographical area. Most of the genetic diversity in both groups was attributable to differences among individuals within populations, although spatial genetic analysis of indigenous populations indicated the existence of isolation by distance. Geographical structuring of indigenous populations was found using clustering analysis, with three sub-clusters of indigenous populations. The highest level of gene diversity and the greatest number of private alleles were found in the central part of the eastern Adriatic coast, while decreases in gene diversity and number of private alleles were evident towards the northwestern Adriatic coast and southern and eastern regions of the Balkan Peninsula. The results of Ecological Niche Modelling during Last Glacial Maximum and Approximate Bayesian Computation suggested two plausible evolutionary trajectories: 1) the species survived in the glacial refugium in southern Adriatic coastal region with subsequent colonization events towards northern, eastern and southern Balkan Peninsula; 2) species survived in several refugia exhibiting concurrent divergence into three genetic groups. The insight into genetic

  2. The phloem-sap feeding mealybug (Ferrisia virgata carries 'Candidatus Liberibacter asiaticus' populations that do not cause disease in host plants.

    Directory of Open Access Journals (Sweden)

    Marco Pitino

    Full Text Available 'Candidatus Liberibacter asiaticus' (Las is the primary causal agent of huanglongbing (HLB, the most devastating disease of citrus worldwide. There are three known insect vectors of the HLB-associated bacteria, and all are members of the Hemiptera: Diaphorina citri (Psyllidae, Trioza erytreae (Triozidae, and Cacopsylla (Psylla citrisuga (Psyllidae. In this study, we found that another hemipteran, the striped mealybug Ferrisia virgata (Cockerell (Hemiptera: Pseudococcidae, was able to acquire and retain Las bacteria. The bacterial titers were positively correlated with the feeding acquisition time on Las-infected leaf discs, with a two-weeks feeding period resulting in Ct values ranging from 23.1 to 36.1 (8.24 × 10(7 to 1.07 × 10(4 Las cells per mealybug. We further discovered that the prophage/phage populations of Las in the mealybugs were different from those of Las in psyllids based on Las prophage-specific molecular markers: infected psyllids harbored the Las populations with prophage/phage FP1 and FP2, while infected mealybugs carried the Las populations with the iFP3 being the dominant prophage/phage. As in the psyllids, Las bacteria were shown to move through the insect gut wall to the salivary glands after being ingested by the mealybug based on a time-course quantitative polymerase chain reaction (qPCR assay of the dissected digestive systems. However, Las populations transmitted by the mealybugs did not cause disease in host plants. This is the first evidence of genetic difference among Las populations harbored by different insect vectors and difference among Las populations with respect to whether or not they cause disease in host plants.

  3. Optimum Performance Enhancing Strategies of the Gas Turbine Based on the Effective Temperatures

    Directory of Open Access Journals (Sweden)

    Ibrahim Thamir K.

    2016-01-01

    Full Text Available Gas turbines (GT have come to play a significant role in distributed energy systems due to its multi-fuel capability, compact size and low environmental impact and reduced cost. Nevertheless, the low electrical efficiency, typically about 30% (LHV, is an important obstruction to the development of the GT plants. New strategies are designed for the GT plant, to increase the overall performance based on the operational modeling and optimization of GT power plants. The enhancing strategies effect on the GT power plant’s performance (with intercooler, two-shaft, reheat and regenerative based on the real power plant of GT. An analysis based on thermodynamics has been carried out on the modifications of the cycle configurations’ enhancements. Then, the results showed the effect of the ambient and turbine inlet temperatures on the performance of the GT plants to select an optimum strategy for the GT. The performance model code to compare the strategies of the GT plants were developed utilizing the MATLAB software. The results show that, the best thermal efficiency occurs in the intercooler-regenerative-reheated GT strategy (IRHGT; it decreased from 51.5 to 48%, when the ambient temperature increased (from 273 to 327K. Furthermore, the thermal efficiency of the GT for the strategies without the regenerative increased (about 3.3%, while thermal efficiency for the strategies with regenerative increased (about 22% with increased of the turbine inlet temperature. The lower thermal efficiency occurs in the IHGT strategy, while the higher thermal efficiency occurs in the IRHGT strategy. However, the power output variation is more significant at a higher value of the turbine inlet temperature. The simulation model gives a consistent result compared with Baiji GT plant. The extensive modeling performed in this study reveals that; the ambient temperature and turbine inlet temperature are strongly influenced on the performance of GT plant.

  4. Determination of optimum filter in inferolateral view of myocardial SPECT

    International Nuclear Information System (INIS)

    Takavar; Eftekhari, M.; Fallahi, B.; Shamsipour, Gh.; Sohrabi, M.; Saghari, M.

    2004-01-01

    Background: In myocardial perfusion SPECT imaging, images are degraded by photon attenuation, distance-dependent collimator, detector response and photon scattering. As filters greatly affect quality of nuclear medicine images, in this study determination of optimum filter for inferolateral view is our prime objective. Materials and Methods: .A phantom simulating heart left ventricle was built. About 1mCi of 99m Tc, was injected into the phantom. Images were taken from this phantom. Parzen, Hamming, Hanning, Butter worth and Gaussian filters were exerted on the images obtained from the phantom.. By defining some criteria such as contrast, signal to noise ratio, and defect size delectability, the best filter was determined for our ADAC spect system at our nuclear medicine center. In this study, 27 patients who previously had undergone coronary angiography were chosen to be included. All of these patients revealed significant stenosis in the left circumflex artery. Myocardial SPECT images of these patients had inferolateral defect. The images of these patients were processed with 12 filters including the optimum filters obtained from phantom study and some other non-optimum filters. A nuclear medicine physician quantified the results by assigmng mark from 0 to 4. to every image. 0 mark for images that didn't show the defect properly and 4 for the best one. The data from patient study were analyzed with non-related, non -parametric Friedman test. Results: Nyquist frequency of 0.325 and 0.5 were obtained as the optimum cut-off frequencies for hamming and Hanning filters respectively. Order 11 and cut-off frequency of 0.45 and order 20. with cut-off frequency of 0.5 were found to be optimum for Butter worth and Gaussian filters. In patient studies it was found that, Butter worth filter with cut-off frequency of 0.45 and order of 11 produced the best quality images. Conclusion: In this study. Butter worth filter with cut-off frequency of 0.45 and order of 11 was the

  5. The refining of soybean oil to optimum quality

    Directory of Open Access Journals (Sweden)

    Rusell, J.

    1996-08-01

    Full Text Available One of the objectives of the American Soybean Association is to improve the quality of soybean and related products in Turkey. In order to achieve this, a number of extraction plants and refineries were visited to enable first hand information to be obtained on the type of equipment used in all unit processes, the methodology employed, quality standards and levels of efficiency. The culmination of the visit was a seminar organised jointly by the American Soybean Association and the Turkish Vegetable Oil Association in Istanbul on 22nd September 1989, at which a paper with the above title was presented. A reproduction of this paper is attached which briefly describes the critical areas of soybean oil processing and includes recommendations for quality improvements. It concludes with the comment that provided proper care is taken and optimum refining processes employed, including hydrogenation where appropriate, an impressive range of oils, margarines and shortenings of high quality can ben produced. The author would like to record his grateful thanks to Dr. R. Leysen of the American Soybean Association for all his help and guidance, to Mr. Kenon Marasoglu, Chairman of the Turkish Vegetable Oil Association and to the management and staff of all the factories visited. Acknowledgement is also made to Dr. D. R. Arickson and Mr. L. H. Wiedermann of the American Soybean Association for the use of some technical information from a paper entitled «Soybean Oil-Modern Processing and Utilisation» which is to be published shortly.

    Uno de los objetivos de la Asociación Americana de Soja en Turquía es mejorar la calidad de la soja y de los productos relacionados. En orden a conseguir esto, diversas plantas de extracción y refinerías fueron visitadas para permitir obtener de primera mano información sobre el tipo de equipo usado en todas las unidades de proceso, la metodología empleada, los estándar de calidad y los niveles de eficacia. La

  6. Integration of population genetic structure and plant response to climate change: sustaining genetic resources through evaluation of projected threats

    Science.gov (United States)

    Bryce A. Richardson; Marcus V. Warwell; Mee-Sook Kim; Ned B. Klopfenstein; Geral I. McDonald

    2010-01-01

    To assess threats or predict responses to disturbances, or both, it is essential to recognize and characterize the population structures of forest species in relation to changing environments. Appropriate management of these genetic resources in the future will require (1) understanding the existing genetic diversity/variation and population structure of forest trees...

  7. RELATIONSHIPS BETWEEN PLANT-DENSITY, OUTCROSSING RATES AND SEED SET IN NATURAL AND EXPERIMENTAL POPULATIONS OF SCABIOSA-COLUMBARIA

    NARCIS (Netherlands)

    VANTREUREN, R; BIJLSMA, R; OUBORG, NJ; KWAK, MM

    Outcrossing rates were estimated in both natural and experimental populations of Scabiosa columbaria, a self-compatible, entomophilous, gynodioecious, protandrous perennial. In natural populations, estimates of the outcrossing rate in hermaphrodites were near to one and ranged from 0.84 +/- 0.07 to

  8. Effects of Secondary Plant Metabolites on Microbial Populations: Changes in Community Structure and Metabolic Activity in Contaminated Environments

    Directory of Open Access Journals (Sweden)

    Lucie Musilova

    2016-07-01

    Full Text Available Secondary plant metabolites (SPMEs play an important role in plant survival in the environment and serve to establish ecological relationships between plants and other organisms. Communication between plants and microorganisms via SPMEs contained in root exudates or derived from litter decomposition is an example of this phenomenon. In this review, the general aspects of rhizodeposition together with the significance of terpenes and phenolic compounds are discussed in detail. We focus specifically on the effect of SPMEs on microbial community structure and metabolic activity in environments contaminated by polychlorinated biphenyls (PCBs and polyaromatic hydrocarbons (PAHs. Furthermore, a section is devoted to a complex effect of plants and/or their metabolites contained in litter on bioremediation of contaminated sites. New insights are introduced from a study evaluating the effects of SPMEs derived during decomposition of grapefruit peel, lemon peel, and pears on bacterial communities and their ability to degrade PCBs in a long-term contaminated soil. The presented review supports the “secondary compound hypothesis” and demonstrates the potential of SPMEs for increasing the effectiveness of bioremediation processes.

  9. Determination of optimum oven cooking procedures for lean beef products.

    Science.gov (United States)

    Rodas-González, Argenis; Larsen, Ivy L; Uttaro, Bethany; Juárez, Manuel; Parslow, Joyce; Aalhus, Jennifer L

    2015-11-01

    In order to determine optimum oven cooking procedures for lean beef, the effects of searing at 232 or 260°C for 0, 10, 20 or 30 min, and roasting at 160 or 135°C on semimembranosus (SM) and longissimus lumborum (LL) muscles were evaluated. In addition, the optimum determined cooking method (oven-seared for 10 min at 232°C and roasted at 135°C) was applied to SM roasts varying in weight from 0.5 to 2.5 kg. Mainly, SM muscles seared for 0 or 10 min at 232°C followed by roast at 135°C had lower cooking loss, higher external browning color, more uniform internal color, and were more tender and flavorful (P searing is the recommended oven cooking procedure; with best response from muscle roast weight ≥1 kg.

  10. RECENT APPROACHES IN THE OPTIMUM CURRENCY AREAS THEORY

    Directory of Open Access Journals (Sweden)

    AURA SOCOL

    2011-04-01

    Full Text Available This study is dealing with the endogenous characteristic of the OCA criteria, starting from the idea that a higherconformity of the business cycles will result in a better timing of the economic cycles and, thus, in getting closerto the quality of an optimum currency area. Thus, if the classical theory is focused on a static approach of theproblem, the new theories assert that these conditions are dynamic, and they cannot be positively affected evenby the establishment of the Economic and Monetary Union. The consequences are overwhelming, as theendogenous approach shows that a monetary union can be achieved even if all the conditions mentioned inMundell’s optimum currency areas theory are not met, showing that some of them may also be met subsequentto the unification. Thus, a country joining a monetary union, althogh it does not meet the criteria for an optimumcurrency area, will ex post lead to the increase of the integration and business cycle correlation degree.

  11. Optimum design of exploding pusher target to produce maximum neutrons

    International Nuclear Information System (INIS)

    Kitagawa, Y.; Miyanaga, N.; Kato, Y.; Nakatsuka, M.; Nishiguchi, A.; Yabe, T.; Yamanaka, C.

    1985-03-01

    Exploding pusher target experiments have been conducted with the 1.052-μm GEKKO MII two-beam glass laser system to design an optimum target, which couples to the incident laser light most effectively to produce the maximum neutrons. Since hot electrons preheat the shell entirely in spite of strongly nonuniform irradiation, a simple model can design the optimum target, of which the shell/fuel interface is accelerated to 0.5 to 0.7 times the initial radius within a laser pulse. A 2-dimensional computer simulation supports this target design. The scaling of the neutron yield N with the laser power P is N ∝ P 2.4±0.4 . (author)

  12. Determination of the Optimum Ozone Product on the Plasma Ozonizer

    International Nuclear Information System (INIS)

    Agus Purwadi; Widdi Usada; Suryadi; Isyuniarto; Sri Sukmajaya

    2002-01-01

    An experiment of the optimum ozone product determination on the cylindrical plasma ozonizer has been done. The experiment is carried out by using alternating high voltage power supply, oscilloscope CS-1577 A, flow meter and spectronik-20 instrument for the absorbance solution samples which produced by varying the physics parameter values of the discharge alternating high voltage and velocity of oxygen gas input. The plasma ozonizer is made of cylinder stainless steel as the electrode and cylinder glass as the dielectric with 1.00 mm of the discharge gap and 7.225 mm 3 of the discharge tube volume. The experiment results shows that the optimum ozone product is 0.360 mg/s obtained at the the discharge of alternating high voltage of 25.50 kV, the frequency of 1.00 kHz and the rate of oxygen gas input of 1.00 lpm. (author)

  13. Optimum Design of Heat Exchangers Networks Part -I: Software Development

    International Nuclear Information System (INIS)

    Gabr, E.M.A.; EI-Temtamy, S.A.; Deriasl, S.F.; Moustafa, H.A.

    2004-01-01

    In this paper, we have developed a computerized framework for Heat Exchanger Network Synthesis (HENS) with optimality conditions of achieving the least operating and capital cost. The framework of HEN design involves the development three-computer programs, which applied sequentially to design an optimum HEN. The first program Automatic Minimum Utilities [AMU] developed for automatic formulation of LP equations, these equations can be solved by the optimization software [LINDO] to predict minimum hot and cold utilities. The second program based on Vertical Heat Transfer Method [VHTM] for predicting minimum overall heat transfer area and defining the optimum δbT m in. The third program [Mod.RESHEX] developed for targeting of heat transfer area and automatic synthesis of HEN. This program represents the modifications and development of RESHEX method to overcome the design defects, which appeared on original RESHEX applications

  14. A methodology for selecting optimum organizations for space communities

    Science.gov (United States)

    Ragusa, J. M.

    1978-01-01

    This paper suggests that a methodology exists for selecting optimum organizations for future space communities of various sizes and purposes. Results of an exploratory study to identify an optimum hypothetical organizational structure for a large earth-orbiting multidisciplinary research and applications (R&A) Space Base manned by a mixed crew of technologists are presented. Since such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than the empirical testing of it. The principal finding of this research was that a four-level project type 'total matrix' model will optimize the effectiveness of Space Base technologists. An overall conclusion which can be reached from the research is that application of this methodology, or portions of it, may provide planning insights for the formal organizations which will be needed during the Space Industrialization Age.

  15. Determining optimum aging time using novel core flooding equipment

    DEFF Research Database (Denmark)

    Ahkami, Mehrdad; Chakravarty, Krishna Hara; Xiarchos, Ioannis

    2016-01-01

    the optimum aging time regardless of variations in crude oil, rock, and brine properties. State of the art core flooding equipment has been developed that can be used for consistently determining the resistivity of the coreplug during aging and waterflooding using advanced data acquisition software......New methods for enhanced oil recovery are typically developed using core flooding techniques. Establishing reservoir conditions is essential before the experimental campaign commences. The realistic oil-rock wettability can be obtained through optimum aging of the core. Aging time is affected....... In the proposed equipment, independent axial and sleeve pressure can be applied to mimic stresses at reservoir conditions. 10 coreplugs (four sandstones and six chalk samples) from the North Sea have been aged for more than 408 days in total and more than 29000 resistivity data points have been measured...

  16. Application of customer-interruption costs for optimum distribution planning

    International Nuclear Information System (INIS)

    Mok, Y.L.; Chung, T.S.

    1996-01-01

    We present a new methodology for obtaining optimum values of the integrated cost of utility investment with customer interruption in distribution planning for electric power systems by determining the reliability cost and worth of the distribution system. Reliability cost refers to investment cost of the utility in achieving a defined level of reliability. Reliability worth is the benefit gained by the utility customer from an increase of reliability. A computer program has been developed to determine comparative reliability indices for a typical distribution network. With the average interruption cost, outage duration, average disconnected load, cost data for distribution equipment, etc. being known, the relation between reliability cost, reliability worth and reliability at the specified load point are obtained. The optimum reliability of the distribution system is then determined from the minimum cost to the utility with customer interruption. The applicability of this approach is demonstrated by several practical networks. (Author)

  17. Optimum Conditions for Uricase Enzyme Production by Gliomastix gueg

    Directory of Open Access Journals (Sweden)

    Atalla, M. M.

    2009-01-01

    Full Text Available Nineteen strains of microorganisms were screened for uricase production. Gliomastix gueg was recognized to produce high levels of the enzyme. The optimum fermentation conditions for uricase production by Gliomastix gueg were examined. Results showed that uric acid medium was the most favorable one, the optimum temperature was at 30ºC, and incubation period required for maximum production was 8 days with aeration level at 150 rpm and at pH 8.0. Sucrose proved to be the best carbon source, uric acid was found to be the best nitrogen source. Both, dipotassium hydrogen phosphate and ferrous chloride as well as some vitamins gave the highest amount of uricase by Gliomastix gueg.

  18. Demographic surveillance and health status of population within 0-5 km radius of proposed nuclear power plant at village Gorakhpur, District Fatehabad, Haryana, India

    International Nuclear Information System (INIS)

    Singh, Takdir; Nimble, Sarina; Jyotsana; Garg, Vinod Kumar; Narayanan, Usha

    2012-01-01

    Generation of power is a fundamental catalyst to the economic development of a country. India needs more power in order to have a strong industrial base and for infrastructure development. It is essential to take a baseline of the target area with an objective to know demographic details, health status of the area. This study was conducted to find out the demographic details and health status of the population within 0-5 km radius of proposed Nuclear Power Plant (NPP) site covering five villages of Fatehabad and Hisar districts. The study methodology includes Interview Schedule for data collection. Of the total population from 4501 households covered, 51.60% were male and 48.40% were females. The total population of the study area is 24415. The core observation in the study area pertaining to demographic and health status studies indicate that the literacy rate is 62.92% and mostly population is literate up to metric (50.16%), mostly population falls in the age group between 11-30 years, unemployment status of population is 70.50%. Most prevalent diseases at the time of study were Fever (6.10%), Cold/Cough (7.07%), Wounds (5 .22%), Irritation/Skin rashes (1.62%) and Respiratory Problems (2.36%). Talking about other important diseases like Cancer (0.0002.86%), Congenital Malformation (0.0002.86%), Deaf and dumb (0.0011%), Mental Retardation (0.0007%) and Polio are found (0.0006%) out of total population. So in the nut shell it can be concluded that the literacy rate is good and most of the surveyed population is healthy and there are no serious health problems in the area related to health point of view. (author)

  19. Optimum biasing of integral equations in Monte Carlo calculations

    International Nuclear Information System (INIS)

    Hoogenboom, J.E.

    1979-01-01

    In solving integral equations and estimating average values with the Monte Carlo method, biasing functions may be used to reduce the variancee of the estimates. A simple derivation was used to prove the existence of a zero-variance collision estimator if a specific biasing function and survival probability are applied. This optimum biasing function is the same as that used for the well known zero-variance last-event estimator

  20. Optimum design of Nd-doped fiber optical amplifiers

    DEFF Research Database (Denmark)

    Rasmussen, Thomas; Bjarklev, Anders Overgaard; Lumholt, Ole

    1992-01-01

    The waveguide parameters for a Nd-doped fluoride (Nd:ZBLANP) fiber amplifier have been optimized for small-signal and booster operation using an accurate numerical model. The optimum cutoff wavelength is shown to be 800 nm and the numerical aperture should be made as large as possible. Around 80%......% booster quantum conversion efficiency can be reached for an input power of 10 dBm and a pump power of 100 mW by the use of one filter...

  1. Optimum concrete compression strength using bio-enzyme

    OpenAIRE

    Bagio Tony Hartono; Basoeki Makno; Tistogondo Julistyana; Pradana Sofyan Ali

    2017-01-01

    To make concrete with high compressive strength and has a certain concrete specifications other than the main concrete materials are also needed concrete mix quality control and other added material is also in line with the current technology of concrete mix that produces concrete with specific characteristics. Addition of bio enzyme on five concrete mixture that will be compared with normal concrete in order to know the optimum level bio-enzyme in concrete to increase the strength of the con...

  2. Theoretical and numerical study of an optimum design algorithm

    International Nuclear Information System (INIS)

    Destuynder, Philippe.

    1976-08-01

    This work can be separated into two main parts. First, the behavior of the solution of an elliptic variational equation is analyzed when the domain is submitted to a small perturbation. The case of inequations is also considered. Secondly the previous results are used for deriving an optimum design algorithm. This algorithm was suggested by the center-method proposed by Huard. Numerical results show the superiority of the method on other different optimization techniques [fr

  3. Generating AN Optimum Treatment Plan for External Beam Radiation Therapy.

    Science.gov (United States)

    Kabus, Irwin

    1990-01-01

    The application of linear programming to the generation of an optimum external beam radiation treatment plan is investigated. MPSX, an IBM linear programming software package was used. All data originated from the CAT scan of an actual patient who was treated for a pancreatic malignant tumor before this study began. An examination of several alternatives for representing the cross section of the patient showed that it was sufficient to use a set of strategically placed points in the vital organs and tumor and a grid of points spaced about one half inch apart for the healthy tissue. Optimum treatment plans were generated from objective functions representing various treatment philosophies. The optimum plans were based on allowing for 216 external radiation beams which accounted for wedges of any size. A beam reduction scheme then reduced the number of beams in the optimum plan to a number of beams small enough for implementation. Regardless of the objective function, the linear programming treatment plan preserved about 95% of the patient's right kidney vs. 59% for the plan the hospital actually administered to the patient. The clinician, on the case, found most of the linear programming treatment plans to be superior to the hospital plan. An investigation was made, using parametric linear programming, concerning any possible benefits derived from generating treatment plans based on objective functions made up of convex combinations of two objective functions, however, this proved to have only limited value. This study also found, through dual variable analysis, that there was no benefit gained from relaxing some of the constraints on the healthy regions of the anatomy. This conclusion was supported by the clinician. Finally several schemes were found that, under certain conditions, can further reduce the number of beams in the final linear programming treatment plan.

  4. Choice of economical optimum blanket of hybrid reactors

    Energy Technology Data Exchange (ETDEWEB)

    Blinkin, V L; Novikov, V M

    1981-01-01

    The economical effectiveness of symbiotic power systems depends on the choice of the correlation between energy production and fissile fuel production in blankets of controlled thermonuclear fusion reactor (CTR), what is investigated here. It is shown that the optimum value of this correlation essentially depends on the ratio between the specific costs for energy production in hybrid thermonuclear reactors and that in fission reactors as part of the symbiotic system.

  5. Real-time assessment of radiation burden of the population in the vicinity of nuclear power plants during radiation accidents

    International Nuclear Information System (INIS)

    Stubna, M.

    1986-01-01

    The method is presented of real-time calculation of the radiation situation (dose equivalents) in the environs of a nuclear power plant in case of an accident involving the release of radioactive substances into the atmosphere, this for the potentially most significant exposure paths in the initial and medium stages of the accident. The method allows to take into consideration the time dependence of the rate of radioactive substance release from the nuclear power plant and to assess the development in space and time of the radiation situation in the environs of the nuclear power plant. The use of the method is illustrated by an example of the calculation of the development of the radiation situation for model accidents of a hypothetical PWR with containment. (author)

  6. An integrated expert system for optimum in core fuel management

    International Nuclear Information System (INIS)

    Abd Elmoatty, Mona S.; Nagy, M.S.; Aly, Mohamed N.; Shaat, M.K.

    2011-01-01

    Highlights: → An integrated expert system constructed for optimum in core fuel management. → Brief discussion of the ESOIFM Package modules, inputs and outputs. → Package was applied on the DALAT Nuclear Research Reactor (0.5 MW). → The Package verification showed good agreement. - Abstract: An integrated expert system called Efficient and Safe Optimum In-core Fuel Management (ESOIFM Package) has been constructed to achieve an optimum in core fuel management and automate the process of data analysis. The Package combines the constructed mathematical models with the adopted artificial intelligence techniques. The paper gives a brief discussion of the ESOIFM Package modules, inputs and outputs. The Package was applied on the DALAT Nuclear Research Reactor (0.5 MW). Moreover, the data of DNRR have been used as a case study for testing and evaluation of ESOIFM Package. This paper shows the comparison between the ESOIFM Package burn-up results, the DNRR experimental burn-up data, and other DNRR Codes burn-up results. The results showed good agreement.

  7. Optimum profit model considering production, quality and sale problem

    Science.gov (United States)

    Chen, Chung-Ho; Lu, Chih-Lun

    2011-12-01

    Chen and Liu ['Procurement Strategies in the Presence of the Spot Market-an Analytical Framework', Production Planning and Control, 18, 297-309] presented the optimum profit model between the producers and the purchasers for the supply chain system with a pure procurement policy. However, their model with a simple manufacturing cost did not consider the used cost of the customer. In this study, the modified Chen and Liu's model will be addressed for determining the optimum product and process parameters. The authors propose a modified Chen and Liu's model under the two-stage screening procedure. The surrogate variable having a high correlation with the measurable quality characteristic will be directly measured in the first stage. The measurable quality characteristic will be directly measured in the second stage when the product decision cannot be determined in the first stage. The used cost of the customer will be measured by adopting Taguchi's quadratic quality loss function. The optimum purchaser's order quantity, the producer's product price and the process quality level will be jointly determined by maximising the expected profit between them.

  8. An optimum analysis sequence for environmental gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    De la Torre, F.; Rios M, C.; Ruvalcaba A, M. G.; Mireles G, F.; Saucedo A, S.; Davila R, I.; Pinedo, J. L., E-mail: fta777@hotmail.co [Universidad Autonoma de Zacatecas, Centro Regional de Estudis Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2010-10-15

    This work aims to obtain an optimum analysis sequence for environmental gamma-ray spectroscopy by means of Genie 2000 (Canberra). Twenty different analysis sequences were customized using different peak area percentages and different algorithms for: 1) peak finding, and 2) peak area determination, and with or without the use of a library -based on evaluated nuclear data- of common gamma-ray emitters in environmental samples. The use of an optimum analysis sequence with certified nuclear information avoids the problems originated by the significant variations in out-of-date nuclear parameters of commercial software libraries. Interference-free gamma ray energies with absolute emission probabilities greater than 3.75% were included in the customized library. The gamma-ray spectroscopy system (based on a Ge Re-3522 Canberra detector) was calibrated both in energy and shape by means of the IAEA-2002 reference spectra for software intercomparison. To test the performance of the analysis sequences, the IAEA-2002 reference spectrum was used. The z-score and the reduced {chi}{sup 2} criteria were used to determine the optimum analysis sequence. The results show an appreciable variation in the peak area determinations and their corresponding uncertainties. Particularly, the combination of second derivative peak locate with simple peak area integration algorithms provides the greater accuracy. Lower accuracy comes from the combination of library directed peak locate algorithm and Genie's Gamma-M peak area determination. (Author)

  9. An optimum analysis sequence for environmental gamma-ray spectrometry

    International Nuclear Information System (INIS)

    De la Torre, F.; Rios M, C.; Ruvalcaba A, M. G.; Mireles G, F.; Saucedo A, S.; Davila R, I.; Pinedo, J. L.

    2010-10-01

    This work aims to obtain an optimum analysis sequence for environmental gamma-ray spectroscopy by means of Genie 2000 (Canberra). Twenty different analysis sequences were customized using different peak area percentages and different algorithms for: 1) peak finding, and 2) peak area determination, and with or without the use of a library -based on evaluated nuclear data- of common gamma-ray emitters in environmental samples. The use of an optimum analysis sequence with certified nuclear information avoids the problems originated by the significant variations in out-of-date nuclear parameters of commercial software libraries. Interference-free gamma ray energies with absolute emission probabilities greater than 3.75% were included in the customized library. The gamma-ray spectroscopy system (based on a Ge Re-3522 Canberra detector) was calibrated both in energy and shape by means of the IAEA-2002 reference spectra for software intercomparison. To test the performance of the analysis sequences, the IAEA-2002 reference spectrum was used. The z-score and the reduced χ 2 criteria were used to determine the optimum analysis sequence. The results show an appreciable variation in the peak area determinations and their corresponding uncertainties. Particularly, the combination of second derivative peak locate with simple peak area integration algorithms provides the greater accuracy. Lower accuracy comes from the combination of library directed peak locate algorithm and Genie's Gamma-M peak area determination. (Author)

  10. WHAT IS THE OPTIMUM SIZE OF GOVERNMENT: A SUGGESTION

    Directory of Open Access Journals (Sweden)

    Aykut Ekinci

    2011-01-01

    Full Text Available What is the optimum size of government? When the rule of law and the establishment of private property rights are taken into consideration, it is clear that the answer will not be at some 0%. On the other hand, when the experience of the old Soviet Union, East Germany and North Korea is considered, the answer will not be at some 100% either. Therefore, extreme points should not be the right answer. This study offers using normal distribution to answer this question. The study has revealed the following findings: (i The total amount of public expenditures as % of GDP, a is at minimum level at 4.55% rate, b is at optimum level at 13.4% rate, c is at maximum level at 31.7%. (ii Thus, as a fiscal rule, countries should: a choose the total amount of public expenditures as % of GDP ≤ 31.7% b target 13.4%. (iii Tree dimensional (3D normal distribution demonstrates that a healthy market system could be built upon a healthy government system (iv This approach rejects Wagner’s law. In a healthy growing economy, optimum government size could be kept at 13.4%. (v The UK, the USA and the European countries have been in the Keynesian-Marxist area, which reduces their average growth.

  11. Optimum Antenna Downtilt Angles for Macrocellular WCDMA Network

    Directory of Open Access Journals (Sweden)

    Niemelä Jarno

    2005-01-01

    Full Text Available The impact of antenna downtilt on the performance of cellular WCDMA network has been studied by using a radio network planning tool. An optimum downtilt angle has been evaluated for numerous practical macrocellular site and antenna configurations for electrical and mechanical antenna downtilt concepts. The aim of this massive simulation campaign was expected to provide an answer to two questions: firstly, how to select the downtilt angle of a macrocellular base station antenna? Secondly, what is the impact of antenna downtilt on system capacity and network coverage? Optimum downtilt angles were observed to vary between – depending on the network configuration. Moreover, the corresponding downlink capacity gains varied between – . Antenna vertical beamwidth affects clearly the required optimum downtilt angle the most. On the other hand, with wider antenna vertical beamwidth, the impact of downtilt on system performance is not such imposing. In addition, antenna height together with the size of the dominance area affect the required downtilt angle. Finally, the simulation results revealed how the importance of the antenna downtilt becomes more significant in dense networks, where the capacity requirements are typically also higher.

  12. Planning of optimum production from a natural gas field

    Energy Technology Data Exchange (ETDEWEB)

    Van Dam, J

    1968-03-01

    The design of an optimum development plan for a natural gas field always depends on the typical characteristics of the producing field, as well as those of the market to be served by this field. Therefore, a good knowledge of the field parameters, such as the total natural gas reserves, the well productivity, and the dependence of production rates on pipeline pressure and depletion of natural gas reserves, is required prior to designing the development scheme of the field, which in fact depends on the gas-sales contract to be concluded in order to commit the natural gas reserves to the market. In this paper these various technical parameters are discussed in some detail, and on this basis a theoretical/economical analysis of natural gas production is given. For this purpose a simplified economical/mathematical model for the field is proposed, from which optimum production rates at various future dates can be calculated. The results of these calculations are represented in a dimensionless diagram which may serve as an aid in designing optimum development plans for a natural gas field. The use of these graphs is illustrated in a few examples.

  13. The theory of an ‘optimum currency area’

    Directory of Open Access Journals (Sweden)

    Jarosław Kundera

    2012-12-01

    Full Text Available The main goal of this paper is to analyse and distinguish the main components of the theory of an ‘Optimum Currency Area’. The theory of an optimum currency area indicates some essential elements as preconditions for the successful introduction of a common currency: high mobility of labour, openness of the economy defined as a high proportion of tradable to non-tradable goods, and high diversification of domestic production before joining the union. The article’s analysis helps to better understanding the reasons of the current crisis in the euro zone. The main problem with a common currency area is the adjustment to imbalances, which cannot take place through exchange rates in conditions of a common currency. The missing elements of the theory are the role of the mobility of capital to correct interregional balance of payments disequilibria and lack of a common budget with sufficient own resources during the occurrence of debt crises in member countries. The theory of an optimum currency area has noticed the importance of coordination between fiscal and monetary policy and the necessity of redistribution of resources among partners. However, it does not say much about the methods applied, how to deal with debt crises and what the cost of a potential breaking up of monetary union would be.

  14. Semianalytical and Seminumerical Calculations of Optimum Material Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Gunnar

    1963-06-15

    Perturbation theory applied to the multigroup diffusion equations gives a general condition for optimum distribution of reactor materials. A certain function of the material densities and the fluxes, here called the W (eight) function, must thus be constant where the variable material density is larger than zero if changes in this density affect only the group constants where the changes occur. The weight function is, however, generally a complicated function and complete solutions have therefore previously been presented only for the special case when constant weight function implies constant thermal flux. It is demonstrated that the condition of constant weight function can be used together with well known methods for numerical solution of the multigroup diffusion equations to obtain optimum material distributions also when the thermal flux varies over the core. Solution of the minimum fuel mass problem for two reflected reactors thus shows that an effective reflector such as D{sub 2}O gives a peak in the optimum fuel distribution at the core-reflector interface, while an ineffective reflector such as a breeder blanket or a steel tank wall 'pushes' the fuel away from the strongly absorbing zone. It is also interesting to compare the effective reflector case with analytically obtained solutions corresponding to flat power density, flat thermal flux and flat fuel density.

  15. Optimum heat power cycles for specified boundary conditions

    International Nuclear Information System (INIS)

    Ibrahim, O.M.; Klein, S.A.; Mitchell, J.W.

    1991-01-01

    In this paper optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equal to (or well approximated by) η = 1 - sq. root T L.in /φT H.in where φ is a factor relating the entropy changes during heat rejection and heat addition

  16. Optimum moisture levels for biodegradation of mortality composting envelope materials.

    Science.gov (United States)

    Ahn, H K; Richard, T L; Glanville, T D

    2008-01-01

    Moisture affects the physical and biological properties of compost and other solid-state fermentation matrices. Aerobic microbial systems experience different respiration rates (oxygen uptake and CO2 evolution) as a function of moisture content and material type. In this study the microbial respiration rates of 12 mortality composting envelope materials were measured by a pressure sensor method at six different moisture levels. A wide range of respiration (1.6-94.2mg O2/g VS-day) rates were observed for different materials, with alfalfa hay, silage, oat straw, and turkey litter having the highest values. These four envelope materials may be particularly suitable for improving internal temperature and pathogen destruction rates for disease-related mortality composting. Optimum moisture content was determined based on measurements across a range that spans the maximum respiration rate. The optimum moisture content of each material was observed near water holding capacity, which ranged from near 60% to over 80% on a wet basis for all materials except a highly stabilized soil compost blend (optimum around 25% w.b.). The implications of the results for moisture management and process control strategies during mortality composting are discussed.

  17. Optimum structure of Whipple shield against hypervelocity impact

    International Nuclear Information System (INIS)

    Lee, M

    2014-01-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  18. Optimum structure of Whipple shield against hypervelocity impact

    Science.gov (United States)

    Lee, M.

    2014-05-01

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  19. The optimum decision rules for the oddity task.

    Science.gov (United States)

    Versfeld, N J; Dai, H; Green, D M

    1996-01-01

    This paper presents the optimum decision rule for an m-interval oddity task in which m-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur with "roved" or "fixed" experiments (Macmillan & Creelman, 1991, p. 147). It is shown that the commonly used decision rule for an m-interval oddity task corresponds to the special case of highly correlated observations. However, as is also true for the same-different paradigm, there exists a different optimum decision rule when the observations are independent. The relation between the probability of a correct response and d' is derived for the three-interval oddity task. Tables are presented of this relation for the three-, four-, and five-interval oddity task. Finally, an experimental method is proposed that allows one to determine the decision rule used by the observer in an oddity experiment.

  20. Genome-Wide Search for Quantitative Trait Loci Controlling Important Plant and Flower Traits in Petunia Using an Interspecific Recombinant Inbred Population of Petunia axillaris and Petunia exserta.

    Science.gov (United States)

    Cao, Zhe; Guo, Yufang; Yang, Qian; He, Yanhong; Fetouh, Mohammed; Warner, Ryan M; Deng, Zhanao

    2018-05-15

    A major bottleneck in plant breeding has been the much limited genetic base and much reduced genetic diversity in domesticated, cultivated germplasm. Identification and utilization of favorable gene loci or alleles from wild or progenitor species can serve as an effective approach to increasing genetic diversity and breaking this bottleneck in plant breeding. This study was conducted to identify quantitative trait loci (QTL) in wild or progenitor petunia species that can be used to improve important horticultural traits in garden petunia. An F 7 recombinant inbred population derived between Petunia axillaris and P. exserta was phenotyped for plant height, plant spread, plant size, flower counts, flower diameter, flower length, and days to anthesis, in Florida in two consecutive years. Transgressive segregation was observed for all seven traits in both years. The broad-sense heritability estimates for the traits ranged from 0.20 (days to anthesis) to 0.62 (flower length). A genome-wide genetic linkage map consisting 368 single nucleotide polymorphism bins and extending over 277 cM was searched to identify QTL for these traits. Nineteen QTL were identified and localized to five linkage groups. Eleven of the loci were identified consistently in both years; several loci explained up to 34.0% and 24.1% of the phenotypic variance for flower length and flower diameter, respectively. Multiple loci controlling different traits are co-localized in four intervals in four linkage groups. These intervals contain desirable alleles that can be introgressed into commercial petunia germplasm to expand the genetic base and improve plant performance and flower characteristics in petunia. Copyright © 2018, G3: Genes, Genomes, Genetics.