Production Flexibility and Hedging

Directory of Open Access Journals (Sweden)

Georges Dionne

2015-12-01

Full Text Available We extend the analysis on hedging with price and output uncertainty by endogenizing the output decision. Specifically, we consider the joint determination of output and hedging in the case of flexibility in production. We show that the risk-averse firm always maintains a short position in the futures market when the futures price is actuarially fair. Moreover, in the context of an example, we show that the presence of production flexibility reduces the incentive to hedge for all risk averse agents.

Market conditions and hedge fund survival

OpenAIRE

Mark A. Carlson; Jason Steinman

2008-01-01

As the hedge fund industry has grown, there has been increased concern that, during sharp market moves, hedge fund failures could exacerbate the deterioration in financial conditions and deepen a crisis. However, there has not been much formal analysis regarding the impact of financial market conditions on hedge fund survival. To help fill this gap, this paper examines the relationship between financial market conditions and the likelihood of hedge fund failure after controlling for performan...

HEDGING AS A BUSINESS RISK PROTECTION INSTRUMENT

Directory of Open Access Journals (Sweden)

Ivo Šperanda

2015-12-01

Full Text Available This paper deals with hedging which is one of the trading techniques in the futures markets and with the role of hedging as a protecting strategy. Indirectly, hedging affects the competitiveness of a company by reducing overall operating expenses and increasing the level of competitiveness at the same time. The theoretical fundamentals of the hedging strategy are explained, followed by a survey on relevant theoretical findings and research on hedging and its importance in contemporary economic life. Basic types of risk in firms are clearly described, as well as principal hedging models which are in accordance with the International Financial Reporting Standards. Finally, the paper deals with the financial aspects of hedging, stressing the role and the importance of the principle of the financial leverage.

Quadratic Hedging of Basis Risk

Directory of Open Access Journals (Sweden)

Hardy Hulley

2015-02-01

Full Text Available This paper examines a simple basis risk model based on correlated geometric Brownian motions. We apply quadratic criteria to minimize basis risk and hedge in an optimal manner. Initially, we derive the Föllmer–Schweizer decomposition for a European claim. This allows pricing and hedging under the minimal martingale measure, corresponding to the local risk-minimizing strategy. Furthermore, since the mean-variance tradeoff process is deterministic in our setup, the minimal martingale- and variance-optimal martingale measures coincide. Consequently, the mean-variance optimal strategy is easily constructed. Simple pricing and hedging formulae for put and call options are derived in terms of the Black–Scholes formula. Due to market incompleteness, these formulae depend on the drift parameters of the processes. By making a further equilibrium assumption, we derive an approximate hedging formula, which does not require knowledge of these parameters. The hedging strategies are tested using Monte Carlo experiments, and are compared with results achieved using a utility maximization approach.

MITIGATING FINANCIAL RISK BY USING HEDGING STRATEGIES

Directory of Open Access Journals (Sweden)

Anca BUTNARIU

2018-05-01

Full Text Available Financial derivatives are now widely used by corporations to manage exposure to currency, interest rate, and commodity price risks. The motivation for non-financial firms to engage in corporate hedging is one of the most intensively discussed topics in corporate finance research. Recent financial theory suggests that there are several ways through which corporate hedging can increase firm value in the sense of the maximization of shareholder value. A rich body of literature consists of studies that have empirically investigated the theoretical explanations for corporate hedging, literature that presents rather mixed evidence for the drivers of corporate hedging. This paper investigates the effects of hedging activity on non-financial firm value and how operational hedging is related to and differentiated by financial hedging, by providing an extensive overview and synthesis of the existing literature.

The Great Hedge of India

International Nuclear Information System (INIS)

Moxham, Roy

2015-01-01

The 'Great Hedge of India', a 3 700 kilometre-long hedge installed by the British customs to safeguard the colonial salt tax system and avoid salt smuggling totally faded from both memory and records (e.g. maps) in less than a century. Roy Moxham found traces of the hedge in a book footnote and searched it for several years until he found its meagre remains. The speaker wrote a book about this quest. He said that this story reveals how things disappear when they are no longer useful and, especially, when they are linked to parts of history that are not deemed particularly positive (the hedge was a means of colonial power)

Delta hedging strategies comparison

DEFF Research Database (Denmark)

De Giovanni, Domenico; Ortobelli, S.; Rachev, S.T.

2008-01-01

In this paper we implement dynamic delta hedging strategies based on several option pricing models. We analyze different subordinated option pricing models and we examine delta hedging costs using ex-post daily prices of S&P 500. Furthermore, we compare the performance of each subordinated model...

Bet-hedging applications for conservation

Indian Academy of Sciences (India)

Unknown

Bet hedging; Bitterroot wilderness; environmental correlation; grizzly bear; least tern; Sterna antillarum; Ursus arctos horribilis ... market, a hedging investor can reduce the risk of devas- ..... populations were approximated by three methods:.

Hedge Funds as Investors of Last Resort?

OpenAIRE

David J. Brophy; Paige P. Ouimet; Clemens Sialm

2009-01-01

Hedge funds have become important investors in public companies raising equity privately. Hedge funds tend to finance companies that have poor fundamentals and pronounced information asymmetries. To compensate for these shortcomings, hedge funds protect themselves by requiring substantial discounts, negotiating repricing rights, and entering into short positions of the underlying stocks. We find that companies that obtain financing from hedge funds significantly underperform companies that ob...

Crude oil hedging: benchmarking price protection strategies

International Nuclear Information System (INIS)

Krapels, Edward N.; Pratt, Michael

1998-01-01

This report presents a review of hedging (protection against a loss) strategies in the crude oil futures and options markets. The introductory section of the report gives details of hedging instruments, and the purposes of hedging crude oil. Hedging strategies including pure futures strategies, pure options strategies, options combination strategies, exotic (Asian) options strategies, and insurance instruments are described. The West Texas intermediate (WTI) market depth, liquidity and hedging effectiveness are examined, and winners and losers, and energy consumers are considered. The appendix gives tables and charts summarising the outcomes of futures and options strategies under different market conditions and expectations. (UK)

A Study of Perfect Hedges

OpenAIRE

Stoyu I. Ivanov

2017-01-01

In this study, we attempt to identify the asset which has the best hedging characteristics against inflation. We study stock, bond, commodity, real estate and oil indexes. We also study these indexes tracking exchange traded funds (ETFs) to determine the most beneficial tradable asset in addition to the more theoretical index for inflation hedging. We find that, in our sample, oil is the best hedge against inflation, even though three in total are a good hedge—oil, gold and corn—with corn and...

Short Term Hedging Using Futures Contracts

Directory of Open Access Journals (Sweden)

Ioana – Diana PAUN

2012-12-01

Full Text Available The objective of this paper is to demonstrate the effectiveness of risk management portfolio using futures contracts to achieve hedging. The risk can be minimized once measured, and the traditional tool of market risk management is hedging. The objective is to identify the optimum position to minimize the variation in a contract concluded now. Clearly hedging portfolio will reduce not only risk but also profitability. In conclusion hedging aims risk management, no additional gain. Portfolio manager will have the opportunity to carefully consider the relationship between risk and return in order to act according to his profile and targeted results.

Hedging under arbitrage

OpenAIRE

Ruf, Johannes

2010-01-01

It is shown that delta hedging provides the optimal trading strategy in terms of minimal required initial capital to replicate a given terminal payoff in a continuous-time Markovian context. This holds true in market models where no equivalent local martingale measure exists but only a square-integrable market price of risk. A new probability measure is constructed, which takes the place of an equivalent local martingale measure. In order to ensure the existence of the delta hedge, sufficient...

Option Derivatives in Electricity Hedging

Directory of Open Access Journals (Sweden)

P. Pavlátka

2010-01-01

Full Text Available Despite the high volatility of electricity prices, there is still little demand for electricity power options, and the liquidity on the power exchanges of these power derivatives is quite low. One of the reasons is the uncertainty about how to evaluate these electricity options and about finding the right fair value of this product. Hedging of electricity is associated mainly with products such as futures and forwards. However, due to new trends in electricity trading and hedging, it is also useful to think more about options and the principles for working with them in hedging various portfolio positions and counterparties. We can quite often encounter a situation when we need to have a perfect hedge for our customer’s (end user consuming electricity portfolio, or we have to evaluate the volumetric risk (inability of a customer to predict consumption, which is very similar to selling options. Now comes the moment to compare the effects of using options or futures to hedge these open positions. From a practical viewpoint, the Black-Scholes prices appear to be the best available and the simplest method for evaluating option premiums, but there are some limitations that we have to consider.

The Motivation for Hedging Revisited

NARCIS (Netherlands)

Pennings, J.M.E.; Leuthold, R.M.

2000-01-01

This article develops an alternative view on the motivation to hedge. A conceptual model shows how hedging facilitates contract relationships between firms and can solve conflicts between firms. In this model, the contract preferences, level of power, and conflicts in contractual relationships of

Optimal Hedging with the Vector Autoregressive Model

NARCIS (Netherlands)

L. Gatarek (Lukasz); S.G. Johansen (Soren)

2014-01-01

markdownabstract__Abstract__ We derive the optimal hedging ratios for a portfolio of assets driven by a Cointegrated Vector Autoregressive model with general cointegration rank. Our hedge is optimal in the sense of minimum variance portfolio. We consider a model that allows for the hedges to be

Catchments' hedging strategy on evapotranspiration for climatic variability

Science.gov (United States)

Ding, W.; Zhang, C.; Li, Y.; Tang, Y.; Wang, D.; Xu, B.

2017-12-01

Hydrologic responses to climate variability and change are important for human society. Here we test the hypothesis that natural catchments utilize hedging strategies for evapotranspiration and water storage carryover with uncertain future precipitation. The hedging strategy for evapotranspiration in catchments under different levels of water availability is analytically derived from the economic perspective. It is found that there exists hedging between evapotranspiration for current and future only with a portion of water availability. Observation data sets of 160 catchments in the United States covering the period from 1983 to 2003 demonstrate the existence of hedging in catchment hydrology and validate the proposed hedging strategies. We also find that more water is allocated to carryover storage for hedging against the future evapotranspiration risk in the catchments with larger aridity indexes or with larger uncertainty in future precipitation, i.e., long-term climate and precipitation variability control the degree of hedging.

Hedge Ratios for short and leveraged ETFs

Directory of Open Access Journals (Sweden)

Leo Schubert

2011-06-01

Full Text Available Exchange Traded Funds (ETFs exist for stock-, bond- and commodity markets. In most cases the underlying of an ETF is an index. Fund management today uses the active and passive way to construct a portfolio. ETFs can be used for passive portfolio management. Then ETFs with positive leverage factors are preferred. In the frame of active portfolio also the ETFs with negative leverage factors can be applied for the hedge or cross hedge of a portfolio. These hedging possibilities will be analyzed in this paper. Short ETFs exist with different leverage factors. In Europe, the leverage factors 1 (e.g. ShortDAX ETF and 2 (e.g. DJ STOXX 600 Double Short are offered while in the financial markets of the United States factors from 1 to 4 can be found. To investigate the effect of the different leverage factors and other parameters Monte Carlo Simulation was used. The results show e.g. that higher leverage factors achieve higher profits as well as losses. In the case, that a bearish market is supposed, minimizing the variance of the hedge seem not to be until to get better hedging results, due to a very skewed return distribution of the hedge. The risk measure target-shortfall-probability confirms the use of the standard hedge weightings which depend only on the leverage factor. This characteristic remains, when a portfolio has to be hedged instead of the underlying index of the short ETF. For portfolios which have a low correlation with the index return should not be used high leverage factors for hedging, due to the higher volatility and target-shortfall-probability.

Time-varying risk aversion. An application to energy hedging

Energy Technology Data Exchange (ETDEWEB)

Cotter, John [Centre for Financial Markets, School of Business, University College Dublin, Blackrock, Co. Dublin (Ireland); Hanly, Jim [School of Accounting and Finance, Dublin Institute of Technology, Dublin 2 (Ireland)

2010-03-15

Risk aversion is a key element of utility maximizing hedge strategies; however, it has typically been assigned an arbitrary value in the literature. This paper instead applies a GARCH-in-Mean (GARCH-M) model to estimate a time-varying measure of risk aversion that is based on the observed risk preferences of energy hedging market participants. The resulting estimates are applied to derive explicit risk aversion based optimal hedge strategies for both short and long hedgers. Out-of-sample results are also presented based on a unique approach that allows us to forecast risk aversion, thereby estimating hedge strategies that address the potential future needs of energy hedgers. We find that the risk aversion based hedges differ significantly from simpler OLS hedges. When implemented in-sample, risk aversion hedges for short hedgers outperform the OLS hedge ratio in a utility based comparison. (author)

Time-varying risk aversion. An application to energy hedging

International Nuclear Information System (INIS)

Cotter, John; Hanly, Jim

2010-01-01

Risk aversion is a key element of utility maximizing hedge strategies; however, it has typically been assigned an arbitrary value in the literature. This paper instead applies a GARCH-in-Mean (GARCH-M) model to estimate a time-varying measure of risk aversion that is based on the observed risk preferences of energy hedging market participants. The resulting estimates are applied to derive explicit risk aversion based optimal hedge strategies for both short and long hedgers. Out-of-sample results are also presented based on a unique approach that allows us to forecast risk aversion, thereby estimating hedge strategies that address the potential future needs of energy hedgers. We find that the risk aversion based hedges differ significantly from simpler OLS hedges. When implemented in-sample, risk aversion hedges for short hedgers outperform the OLS hedge ratio in a utility based comparison. (author)

Belief elicitation in experiments: Is there a hedging problem?

DEFF Research Database (Denmark)

Blanco, Mariana; Engelmann, Dirk; Koch, Alexander

2010-01-01

Belief-elicitation experiments usually reward accuracy of stated beliefs in addition to payments for other decisions. But this allows risk-averse subjects to hedge with their stated beliefs against adverse outcomes of the other decisions. So can we trust the existing belief-elicitation results...... opportunities are very prominent. If hedging opportunities are transparent, and incentives to hedge are strong, many subjects do spot hedging opportunities and respond to them. The bias can go beyond players actually hedging themselves, because some expect others to hedge and best respond to this....

Report on "American Option Pricing and Hedging Strategies"

OpenAIRE

Zhang, Jinshan

2007-01-01

This paper mainly discusses the American option's hedging strategies via binomialmodel and the basic idea of pricing and hedging American option. Although the essential scheme of hedging is almost the same as European option, small differences may arise when simulating the process for American option holder has more rights, spelling that the option can be exercised at anytime before its maturity. Our method is dynamic-hedging method.

HEDGE FUND MANAGERIAL INCENTIVES AND PERFORMANCE

Directory of Open Access Journals (Sweden)

Nor Hadaliza ABD RAHMAN

2011-07-01

Full Text Available The growth of the hedge fund industry over the decades has brought an interesting form of performance contract between the portfolio managers and their investors. The contractual relation has given an impact to the performance of the hedge fund industry, which benefited both fund managers and investors. Furthermore, it has created more investors and fund managers to participate in this high risk and high return investment. Currently, many issues on fee structures and performancebased incentives have been discussed. Do these issues affect the performance of the hedge fund in the market? This paper will investigate the issues in Australian market. It will empirically analyze the hedge fund performance in relation to the market performance and whether managerial incentives and discretions associated with better fund performance.

Risk management in Swedish hedge funds

OpenAIRE

Fri, Samuel; Nilsson, Joakim

2011-01-01

Background: Risk management has always been a complex topic, especially when it comes to hedge funds. Since hedge funds are able to utilize many kinds of financial instruments it is difficult to find a risk management strategy that goes well with them. Not much research regarding the Swedish hedge fund industry and its risk management has been done; hence we find it an interesting topic to focus this thesis on. Purpose: The purpose of this thesis is to increase the knowledge of how Swedish he...

Providing hedging protection for the transaction

International Nuclear Information System (INIS)

Richardson, D.W.

1999-01-01

This presentation dealt with methods for assessing commodity price risk in an asset transaction; the setting of risk management objectives; building hedging into the financing; and internal reporting and accounting to mitigate trading risks. It also provided some recent examples of successful hedging in gas asset transactions. The objectives of risk management and the nature of hedging and speculation were explored. An approach to price risk management was proposed. The development of price risk management tools, and techniques for managing risks involving interest rates, foreign exchange, and commodities were examined. figs

Hedge accounting under IFRS 9: an analysis of reforms

Directory of Open Access Journals (Sweden)

Jatinder Pal Singh

2017-02-01

Full Text Available Pronouncements of regulatory bodies on ‘hedge accounting’ are aimed at ensuring that impact of price changes of hedging relationships are accounted for concurrently. However, it sometimes happens that certain provisions of these standards result in the reporting of enhanced earnings volatility being attributed to hedging relationships which is not economically justified. It is often perceived to be the case by stakeholders that the provisions of IAS 39 on ‘hedge accounting’ do not appropriately reflect and are not aligned with the risk management strategies of entities that attempt to mitigate risk using various hedging relationships. This occasionally results in a reporting entity adopting either a suboptimal hedging strategy that gives it eligibility to account for it using ‘hedge accounting’ or vice versa. Thus entities may be faced with the tradeoff between the benefits of risk mitigation strategies and the benefits derived from adopting ‘hedge accounting’. This motivated the IASB to initiate action for the complete reformulation of the standard on ‘hedge accounting’. The revised standard was pronounced in November 2013 as IFRS 9. In this article, we attempt to evaluate the upgradations introduced by IFRS 9 over its predecessor, IAS 39, with particular reference to the reporting of risk management strategies of affected entities.

Optimal hedging with the cointegrated vector autoregressive model

DEFF Research Database (Denmark)

Gatarek, Lukasz; Johansen, Søren

We derive the optimal hedging ratios for a portfolio of assets driven by a Coin- tegrated Vector Autoregressive model (CVAR) with general cointegration rank. Our hedge is optimal in the sense of minimum variance portfolio. We consider a model that allows for the hedges to be cointegrated with the...

Effects of planting density and bearing-branch composition on the yield of sweet cherry [Prunus avium] grown by hedge-row training

International Nuclear Information System (INIS)

Tomita, A.; Shinya, K.; Watanabe, K.; Inomata, M.

2008-01-01

To improve the yield of sweet cherries (Prunus avium L.) grown by hedge-row training, the following two methods were compared: increased numbers of spurs and bouquet spurs to improve the spur composition and narrowed row intervals to increase planting density. To develop spurs and bouquet spurs, 30 cm long branches were positioned at 30 cm intervals on lateral branches in addition to the conventional spur development from 5 cm current shoots. Although this measure decreased the number of bouquet spurs, it increased the total number of spurs including the conventional short spurs to improve the yield to 1,024 kg/10a from 557 kg/10a using conventional hedge-row training. However, this method decreased solar radiation in the tree crowns thereby lowering fruit quality. In contrast, increasing planting density from 3-m intervals to 2- or 1.5-m intervals did not affect fruit quality. Moreover, in contrast to a yield of 588 kg/10a when row intervals were 3 m, the row intervals narrowed to 2 m and 1.5 m improved the yield to 881 kg/10a and 1,101 kg/10a, respectively. The above results show that decreasing row intervals is an effective method for increasing the yield of sweet cherries grown by hedge-row training without lowering fruit quality

Arbitrage opportunities and their implications to derivative hedging

Science.gov (United States)

Panayides, Stephanos

2006-02-01

We explore the role that random arbitrage opportunities play in hedging financial derivatives. We extend the asymptotic pricing theory presented by Fedotov and Panayides [Stochastic arbitrage return and its implication for option pricing, Physica A 345 (2005) 207-217] for the case of hedging a derivative when arbitrage opportunities are present in the market. We restrict ourselves to finding hedging confidence intervals that can be adapted to the amount of arbitrage risk an investor will permit to be exposed to. The resulting hedging bands are independent of the detailed statistical characteristics of the arbitrage opportunities.

Do Hedge Funds Supply or Demand Liquidity?

OpenAIRE

Petri Jylhä; Kalle Rinne; Matti Suominen

2014-01-01

Regressing hedge funds’ returns on returns to a long–short contrarian trading strategy, a measure of the returns from providing liquidity, we find that hedge funds typically supply liquidity in the stock market. In the cross-section, strict redemption restrictions and large fund size increase funds’ propensity to supply liquidity. In time series, poor market liquidity and good funding conditions increase funds’ propensity to supply liquidity. Although the hedge funds typically supply liquidit...

Hedging Medical Spending Growth: An Adaptive Expectations Approach.

Science.gov (United States)

Lieberthal, Robert D

2016-08-01

Long-term health insurance provides consumers with protection against persistent, negative health shocks. While the stochastic rise in medical spending growth may make some health risks harder to insure, financial assets could act as a hedge for medical spending growth risk. The purpose of this research was to determine whether such hedges exist. The results of this study were two-fold. First, the asset classes with the strongest statistical evidence as hedges were bonds, not stocks. Second, any strategy to hedge medical spending growth involved shorting assets i.e. betting against the bond or stock market. Health insurers writing long-term contracts should combine the use of hedges in the bond market with of portfolio diversification, and may benefit from health policies to moderate the uncertainty of medical spending growth.

Futures hedging effectiveness under the segmentation of bear/bull energy markets

International Nuclear Information System (INIS)

Chang, Chiao-Yi; Lai, Jing-Yi; Chuang, I-Yuan

2010-01-01

This article undertakes eight hedging models (Regression, MD-GARCH, BEKK-GARCH, CCC-GARCH, ECM-MD, ECM-BEKK, ECM-CCC, and state space models) to investigate hedging effectiveness of different price scenarios in energy futures markets. Different models have systematically evidenced that hedging effectiveness is higher in an increasing pattern (termed 'bull markets') than in a decreasing pattern (termed 'bear markets') for crude oil and gasoline futures. That is, findings show asymmetric hedging performance between upward and downward price trends consistently from the most popular hedging models in literature. Out-of-sample examination also suggests that the ranking of hedging effectiveness of different hedging models is not parallel in different price patterns across futures contracts, implying that investors should adjust their hedging strategies accordingly. (author)

The evolution and regulation of hedge funds.

OpenAIRE

Crockett, A.

2007-01-01

Hedge funds have attracted increased attention in recent years. In part, this is because investment in hedge funds is becoming “mainstream”. A wider range of investors has sought exposure to these investment vehicles, and this has been associated with rapid growth in both the number of funds and the volume of assets under management. In part, too, greater attention has been the result of worries that hedge funds could in some circumstances exert a destabilizing infl uence. With the growth in ...

Convertibles and hedge funds as distributors of equity exposure

NARCIS (Netherlands)

Brown, S.; Grundy, B.; Lewis, C.; Verwijmeren, P.

2012-01-01

By buying convertibles and shorting the underlying stock, hedge funds distribute equity exposure to well-diversified shareholders. We find that firms with characteristics that make seasoned equity offerings expensive are more likely to issue convertibles to hedge funds. We conclude that hedge funds

English Language Teaching: Teaching of Hedges

Directory of Open Access Journals (Sweden)

Charles Ko

2014-05-01

Full Text Available A hedge is a mitigating word or sound used to lessen the impact of an utterance. It can be an adjective, for example, ‘Small potato me is not as strong as you’; or an adverb: ‘I maybe can swim faster than you’, while it can also consist of clauses, that it could be regarded as a form of euphemism which should be taught as a main topic in English class of schools around the world. For instance, in Hong Kong schools, based on my observation while teaching in a number of primary and secondary English courses as a tutor, students report that their school teachers usually emphasize the teaching of all cohesive devices in terms of skills of writing while they neglect to explain the importance of the use of hedges in order to show euphemism. In this study, I would adopt Corpus Linguistics, a division of applied linguistics, as methodology to discover a great deal of hedges employed by so-called native speakers of English, for promoting the idiomatic usage of hedges in writing, nevertheless in speaking, so as to help teachers gain resources and inspiration in teaching to students the appropriate English hedges as a consequence of the author’s hard effort while revealing from the selected corpora of this paper.

Futures hedging effectiveness under the segmentation of bear/bull energy markets

Energy Technology Data Exchange (ETDEWEB)

Chang, Chiao-Yi [Department of Money and Banking, National Kaohsiung First University of Science and Technology, No. 2, Jhuoyue Rd., Nanzih, Kaohsiung City, 811 (China); Lai, Jing-Yi; Chuang, I-Yuan [Department of Finance, National Chung-Cheng University, No. 168, University Rd., Ming-Hsiung, Chia-Yi 62102. (China)

2010-03-15

This article undertakes eight hedging models (Regression, MD-GARCH, BEKK-GARCH, CCC-GARCH, ECM-MD, ECM-BEKK, ECM-CCC, and state space models) to investigate hedging effectiveness of different price scenarios in energy futures markets. Different models have systematically evidenced that hedging effectiveness is higher in an increasing pattern (termed 'bull markets') than in a decreasing pattern (termed 'bear markets') for crude oil and gasoline futures. That is, findings show asymmetric hedging performance between upward and downward price trends consistently from the most popular hedging models in literature. Out-of-sample examination also suggests that the ranking of hedging effectiveness of different hedging models is not parallel in different price patterns across futures contracts, implying that investors should adjust their hedging strategies accordingly. (author)

Hedging Capabilities of Bitcoin. Is it the virtual gold?

OpenAIRE

Dyhrberg, Anne Haubo

2015-01-01

This paper sets out to explore the hedging capabilities of bitcoin by applying the asymmetric GARCH methodology used in investigation of gold. The results show that bitcoin can clearly be used as a hedge against stocks in the Financial Times Stock Exchange Index. Additionally bitcoin can be used as a hedge against the American dollar in the short-term. Bitcoin thereby possess some of the same hedging abilities as gold and can be included in the variety of tools available to market analysts to...

Quadratic Hedging Methods for Defaultable Claims

International Nuclear Information System (INIS)

Biagini, Francesca; Cretarola, Alessandra

2007-01-01

We apply the local risk-minimization approach to defaultable claims and we compare it with intensity-based evaluation formulas and the mean-variance hedging. We solve analytically the problem of finding respectively the hedging strategy and the associated portfolio for the three methods in the case of a default put option with random recovery at maturity

A Portfolio Approach to Risk Reduction in Discretely Rebalanced Option Hedges

OpenAIRE

Antonio S. Mello; Henrik J. Neuhaus

1998-01-01

This paper analyses the accumulated hedging errors generated by discretely rebalanced option hedges. We show that simple generalizations of the prior research can underestimate the variance of the accumulated hedging errors and that even with daily rebalancing, these accumulated hedging errors can introduce substantial risk in arbitrage strategies suggested by the Black-Scholes option pricing model. We also show that the correlation between the accumulated hedging errors for different options...

Cross hedging and forward-contract pricing of electricity

International Nuclear Information System (INIS)

Woo, C.-K.; Hoang, K.; Horowitz, I.

2001-01-01

We consider the problem of an electric-power marketer offering a fixed-price forward contract to provide electricity that it purchases from a potentially volatile and unpredictable fledgling spot energy market. One option for the risk-averse marketer who wants to hedge against the spot-price volatility is to engage in cross hedging to reduce the contract's profit variance, and to determine the forward-contract price as a risk-adjusted price - the sum of a baseline price and a risk premium. We show how the marketer can estimate the spot-price relationship between two wholesale energy markets for the purpose of cross hedging, as well as the optimal hedge and the forward contract's baseline price and risk premium

Landscape-moderated bird nest predation in hedges and forest edges

Science.gov (United States)

Ludwig, Martin; Schlinkert, Hella; Holzschuh, Andrea; Fischer, Christina; Scherber, Christoph; Trnka, Alfréd; Tscharntke, Teja; Batáry, Péter

2012-11-01

Landscape-scale agricultural intensification has caused severe declines in biodiversity. Hedges and forest remnants may mitigate biodiversity loss by enhancing landscape heterogeneity and providing habitat to a wide range of species, including birds. However, nest predation, the major cause of reproductive failure of birds, has been shown to be higher in forest edges than in forest interiors. Little is known about how spatial arrangement (configuration) of hedges affects the avian nest predation. We performed an experiment with artificial ground and elevated nests (resembling yellowhammer and whitethroat nests) baited with quail and plasticine eggs. Nests were placed in three habitat types with different degrees of isolation from forests: forest edges, hedges connected to forests and hedges isolated from forests. Nest predation was highest in forest edges, lowest in hedges connected to forests and intermediate in isolated hedges. In the early breeding season, we found similar nest predation on ground and elevated nests, but in the late breeding season nest predation was higher on ground nests than on elevated nests. Small mammals were the main predators of ground nests and appeared to be responsible for the increase in predation from early to late breeding season, whereas the elevated nests were mainly depredated by small birds and small mammals. High predation pressure at forest edges was probably caused by both forest and open-landscape predators. The influence of forest predators may be lower at hedges, leading to lower predation pressure than in forest edges. Higher predation pressure in isolated than connected hedges might be an effect of concentration of predators in these isolated habitats. We conclude that landscape configuration of hedges is important in nest predation, with connected hedges allowing higher survival than isolated hedges and forest edges.

Hedge Fund Performance Attribution Under Various Market Conditions

OpenAIRE

Stafylas, Dimitrios; Anderson, Keith Philip; Uddin, Muhammad Moshfique

2018-01-01

We investigate US hedge funds’ performance. Our proposed model contains exogenous and endogenous break points, based on business cycles and on a regime switching process conditional on different states of the market. During difficult market conditions most hedge fund strategies do not provide significant alphas. At such times hedge funds reduce both the number of their exposures to different asset classes and their portfolio allocations, while some strategies even reverse their exposures. Dir...

Price Uncertainty and Optimal Hedging in the Agricultural Market

Directory of Open Access Journals (Sweden)

Nicolae ISTUDOR

2014-06-01

Full Text Available The increased volatility of the agricultural prices has detrimental effects on the economic welfare and raises concerns regarding poverty and malnutrition at a global level. Financial risk management can be an efficient solution for limiting the effects of international agricultural price volatility. The paper analyzes the behavior of the U.S. wheat and corn prices, emphasizing their highly volatile and unpredictable nature. Given the existence of the basis risk, the estimation of the optimal hedge ratio is needed in order to provide an efficient hedging strategy against price risks. The role of public authorities in this context can consist in promoting education in the fields of hedging and understanding the agricultural price volatility risk. We estimate static and time varying optimal hedge ratios for wheat and corn through several methods. Based on the out of sample hedging effectiveness given by the variance reduction, the methods are compared and the results show that the time varying hedge ratios estimated through rolling window OLS and GARCH methods outperform the static counterparts.

Wavelet multiscale analysis for Hedge Funds: Scaling and strategies

Science.gov (United States)

Conlon, T.; Crane, M.; Ruskin, H. J.

2008-09-01

The wide acceptance of Hedge Funds by Institutional Investors and Pension Funds has led to an explosive growth in assets under management. These investors are drawn to Hedge Funds due to the seemingly low correlation with traditional investments and the attractive returns. The correlations and market risk (the Beta in the Capital Asset Pricing Model) of Hedge Funds are generally calculated using monthly returns data, which may produce misleading results as Hedge Funds often hold illiquid exchange-traded securities or difficult to price over-the-counter securities. In this paper, the Maximum Overlap Discrete Wavelet Transform (MODWT) is applied to measure the scaling properties of Hedge Fund correlation and market risk with respect to the S&P 500. It is found that the level of correlation and market risk varies greatly according to the strategy studied and the time scale examined. Finally, the effects of scaling properties on the risk profile of a portfolio made up of Hedge Funds is studied using correlation matrices calculated over different time horizons.

Cross hedging and forward-contract pricing of electricity

Energy Technology Data Exchange (ETDEWEB)

Woo, C.-K.; Hoang, K. [Energy and Environmental Economics, Inc., 353 Sacramento Street, Suite 1700, 94111 San Francisco, CA (United States); Horowitz, I. [Decision and Information Sciences, Warrington College of Business Administration, University of Florida, 32611 Gainesville, FL (United States)

2001-01-01

We consider the problem of an electric-power marketer offering a fixed-price forward contract to provide electricity that it purchases from a potentially volatile and unpredictable fledgling spot energy market. One option for the risk-averse marketer who wants to hedge against the spot-price volatility is to engage in cross hedging to reduce the contract's profit variance, and to determine the forward-contract price as a risk-adjusted price - the sum of a baseline price and a risk premium. We show how the marketer can estimate the spot-price relationship between two wholesale energy markets for the purpose of cross hedging, as well as the optimal hedge and the forward contract's baseline price and risk premium.

Hedge Funds and Risk-Decoupling

DEFF Research Database (Denmark)

Ringe, Georg

2013-01-01

The law must remain adaptive and responsive to the constantly changing challenges of our society and our business life. One of the most pressing challenges of the past years is the emergence of alternative investment funds, in particular hedge funds, which masterfully exploit the traditional cate...... to the traditional market expectations of shareholders. Based on the insight developed from these policy perspectives, this article develops regulatory reform proposals, particularly with regard to the EU context.......The law must remain adaptive and responsive to the constantly changing challenges of our society and our business life. One of the most pressing challenges of the past years is the emergence of alternative investment funds, in particular hedge funds, which masterfully exploit the traditional...... theoretical perspectives are used as an analytical framework to examine the vast challenges of risk-decoupling: (1) a classical agency costs approach; (2) an information costs perspective; and (3) a view from corporate finance. This Article argues that shareholders with hedged risk exposure do not correspond...

Arbitrage Opportunities and their Implications to Derivative Hedging

OpenAIRE

Panayides, Stephanos

2005-01-01

We explore the role that random arbitrage opportunities play in hedging financial derivatives. We extend the asymptotic pricing theory presented by Fedotov and Panayides [Stochastic arbitrage return and its implication for option pricing, Physica A 345 (2005), 207-217] for the case of hedging a derivative when arbitrage opportunities are present in the market. We restrict ourselves to finding hedging confidence intervals that can be adapted to the amount of arbitrage risk an investor will per...

26 CFR 1.1221-2 - Hedging transactions.

Science.gov (United States)

2010-04-01

... serves a hedging function, or that the transaction serves a similar function or purpose. (4) Coordination... business units. A separate set of books and records is maintained with respect to the activities, assets... under the marking member's method of accounting. (iii) Treatment of intercompany hedging transactions...

Hedging with stock index futures: downside risk versus the variance

NARCIS (Netherlands)

Brouwer, F.; Nat, van der M.

1995-01-01

In this paper we investigate hedging a stock portfolio with stock index futures.Instead of defining the hedge ratio as the minimum variance hedge ratio, we considerseveral measures of downside risk: the semivariance according to Markowitz [ 19591 andthe various lower partial moments according to

Bioenergy and biodiversity: Intensified biomass extraction from hedges impairs habitat conditions for birds.

Science.gov (United States)

Sauerbrei, Ralf; Aue, Birgit; Krippes, Christian; Diehl, Eva; Wolters, Volkmar

2017-02-01

Biomass is increasingly used as an alternative source for energy in Europe. Woody material cut from hedges is considered to provide a suitable complement to maize and oilseed rape, which are currently the dominant biomass sources. Since shrubs and trees are also important habitats for birds, however, coppicing of hedges at the landscape scale may adversely affect the diversity of the avifauna. To evaluate this risk, we estimated the response of hedge birds to three management scenarios differing in cutting intensity and hedge selection. The analysis was done using hedge data of the Lautertal municipality (n = 339 hedges; Vogelsberg area, Hesse, Germany). It focused on 25 bird species, which are all listed in the hedge programme of the German Ornithological Stations. Information on the preferences of these birds for certain hedge features such as height or width was gathered by an extensive literature review. A cluster analysis on the consolidated literature data allowed us to identify three groups of birds according to their preference for certain hedge attributes. Two groups, which included Yellowhammer (Emberiza citrinella L.) (i) and Blackbird (Turdus merula L.) (ii), favoured trees located in hedges, but differed in their preference for hedge shape, with (i) being attracted by long and broad hedges and (ii) by high hedges. The third group, which included the Whitethroat (Sylvia communis L.), preferred small hedges with gaps and medium vegetation density. Spatially explicit suitability models based on these data allowed us to predict the status quo of hedge suitability for these species groups. Field surveys proved the accuracy of the predictions to be sufficient, since the hedge suitability predicted was significantly and positively correlated to the occurrence of 9 out of the 12 testable focal species. Our models predicted biomass extraction to almost always reduce hedge suitability for the three bird groups. Concerning the Yellowhammer and the Blackbird

Penggunaan Hedging oleh Perusahaan Telekomunikasi yang Tercatat Pada Bursa Efek Indonesia

Directory of Open Access Journals (Sweden)

Basyid Ahmad

2017-09-01

Full Text Available The aims of this research were to have a comprehensive understanding on hedging implementation in telecommunication companies and to comprehend the impact of hedge to firm value of the companies. In this research, hedging is the moderating variable between independent variable and dependent variable. The independent variables included profit, firm size, leverage, growth, dividend and liquidity while the dependent variable included firm value. The method used was the ordinary least Square. The samples were taken from 2 telecommunication companies, and the data observed included the quarterly financial data from 2006 to 2015. The findings showed that derivative transactions used as hedge by the companies included cross currency swap, forward and option. Furthermore, the use of hedging foreign exchange was not seen to affect the firm value for the telecommunication company. This is because the 5 moderating variables did not significantly affect the firm value and only 1 moderating variable had a significantly negative effect on the firm value. Keywords: derivative, foreign exchange, firm value, hedge, telecommunication’ companyAbstrak: Tujuan dari penelitian ini adalah untuk menggambarkan penerapan hedging pada perusahaan telekomunikasi publik serta mengetahui dampak hedging terhadap nilai perusahaan. Dalam penelitian ini, hedging merupakan variabel moderating terhadap berbagai variabel yang memengaruhi nilai perusahaan yaitu variabel profitabilitas, firm size, leverage, growth, dividen dan likuiditas. Teknik analisis yang dipakai, yaitu regresi (ordinary least Square. Sedangkan perusahaan yang diteliti sebanyak 2 perusahaan publik dengan data keuangan triwulan sejak tahun 2006 sampai dengan 2015. Hasil penelitian menunjukkan bahwa hedging dilakukan perusahaan telekomunikasi adalah melalui transaksi derivatif, yaitu cross currency swap, forward dan option. Secara umum hedging tidak memengaruhi nilai perusahaan mengingat 5 variabel yang telah

Corporate hedging under a resource rent tax regime

International Nuclear Information System (INIS)

Frestad, Dennis

2010-01-01

In addition to the ordinary corporate income tax, special purpose taxes are sometimes levied to extract abnormal profits arising from the use of natural resources. Such dual tax regimes exist in Norway for oil and hydropower, where the corresponding special purpose tax bases are unaffected by any derivatives payments. Dual tax firms with hedging programs therefore face the risk of potentially large discrepancies between the tax bases for corporate income tax and special purpose tax. I investigate how this tax base asymmetry influences the extent of hedging of value-maximizing firms facing hedgeable as well as unhedgeable risk. Dual tax firms facing deadweight costs in low-profit events generally demand less hedging than ordinary firms, but otherwise respond similarly to characteristics of the underlying risk exposures. The special purpose tax does not influence firms' hedge portfolios in the absence of deadweight cost. (author)

26 CFR 1.446-4 - Hedging transactions.

Science.gov (United States)

2010-04-01

... general. The method of accounting used for hedges of aggregate risk must comply with the matching...) INCOME TAXES Methods of Accounting § 1.446-4 Hedging transactions. (a) In general. Except as provided in... disbursements method of accounting is used or in which § 1.471-6 is used for inventory valuations if, for all...

Limits to Arbitrage and Hedging: Evidence from Commodity Markets

OpenAIRE

Acharya, Viral V; Lochstoer, Lars; Ramadorai, Tarun

2009-01-01

Motivated by the literature on limits-to-arbitrage, we build an equilibrium model of commodity markets in which speculators are capital constrained, and commodity producers have hedging demands for commodity futures. Increases (decreases) in producers' hedging demand (speculators' risk-capacity) increase hedging costs via price-pressure on futures, reduce producers' inventory holdings, and thus spot prices. Consistent with our model, producers' default risk forecasts futures returns, spot pri...

Investable hedge fund indices: how expensive is liquidity ?

OpenAIRE

D. Maspero

2006-01-01

The paper reviews the performance of investable hedge fund indices compared to traditional noninvestable hedge fund indices. While investable indices are characterized by a higher level of liquidity they seem to lag the performance on a risk-adjusted basis of noninvestable indices

Probability Weighting and Loss Aversion in Futures Hedging

NARCIS (Netherlands)

Mattos, F.; Garcia, P.; Pennings, J.M.E.

2008-01-01

We analyze how the introduction of probability weighting and loss aversion in a futures hedging model affects decision making. Analytical findings indicate that probability weighting alone always affects optimal hedge ratios, while loss and risk aversion only have an impact when probability

Socio-cognitive aspects of hedging in two legal discourse genres

Directory of Open Access Journals (Sweden)

Holly Vass

2004-04-01

Full Text Available While there are many studies on hedging in a wide variety of disciplinary discourses, the field of Law, to date, has been largely overlooked. Moreover, most research on hedging approaches the phenomenon from either a textual or pragmatic perspective, and tends to compare the same genre across disciplines. By contrast, the objective of this study was to analyse hedging in two legal written discourse genres, namely U.S. Supreme Court opinions and American law review articles, from a comprehensive, socio-cognitive, intra-disciplinary perspective. Due to the essential roles of intuition and hedging competence in the identification of hedges, qualitative data gathering and interpretation techniques were used. Results indicate that differences between the two genres can be linked to certain prototypical features of the genres themselves, particularly context and communicative purposes. Therefore, it is possible to postulate that hedging is in fact genre-specific, at least insofar as legal genres are concerned. Further comparative research must be done to determine if the same is true in other fields as well.

Corporate hedging under a resource rent tax regime

Energy Technology Data Exchange (ETDEWEB)

Frestad, Dennis [Department of Economics and Business Administration, University of Agder, Serviceboks 422, 4604 Kristiansand (Norway)

2010-03-15

In addition to the ordinary corporate income tax, special purpose taxes are sometimes levied to extract abnormal profits arising from the use of natural resources. Such dual tax regimes exist in Norway for oil and hydropower, where the corresponding special purpose tax bases are unaffected by any derivatives payments. Dual tax firms with hedging programs therefore face the risk of potentially large discrepancies between the tax bases for corporate income tax and special purpose tax. I investigate how this tax base asymmetry influences the extent of hedging of value-maximizing firms facing hedgeable as well as unhedgeable risk. Dual tax firms facing deadweight costs in low-profit events generally demand less hedging than ordinary firms, but otherwise respond similarly to characteristics of the underlying risk exposures. The special purpose tax does not influence firms' hedge portfolios in the absence of deadweight cost. (author)

Inflation Hedging for Long-Term Investors

OpenAIRE

Shaun K. Roache; Alexander P. Attie

2009-01-01

Long-term investors face a common problem-how to maintain the purchasing power of their assets over time and achieve a level of real returns consistent with their investment objectives. While inflation-linked bonds and derivatives have been developed to hedge the effects of inflation, their limited supply and liquidity lead many investors to continue to rely on the indirect hedging properties of traditional asset classes. In this paper, we assess these properties over different time horizons,...

The evolving beta-liquidity relationship of hedge funds

NARCIS (Netherlands)

Siegmann, Arjen; Stefanova, Denitsa

2017-01-01

Hedge funds are known to have liquidity-timing capability, but this might be conditional on aggregate market conditions. To test this, we analyze changes in the relation between hedge funds' stock market exposure and aggregate stock market liquidity. Employing an optimal changepoint approach, we

Hedge Funds As a Alternative Investment Opportunities

Directory of Open Access Journals (Sweden)

Michał Falkowski

2009-09-01

Full Text Available Hedge fund which became a popular alternative investment is a collective term for different types of investment fund. A common feature of these funds is that they have absolute earnings targets, that is they set targets for earnings irrespective of developments on, for example, the stock exchange. The paper deals with the current problem of the financial crisis and the effect it made worldwide for many institutional and private investors. It discusses the role played by hedge funds in developments on the financial markets, and to what extent they are affected by the effects of the crisis, as a recurring feature of every financial crisis. It also shows a wind range of strategies used by hedge funds to achieve their goal.

Delta-gamma-theta Hedging of Crude Oil Asian Options

Directory of Open Access Journals (Sweden)

Juraj Hruška

2015-01-01

Full Text Available Since Black-Scholes formula was derived, many methods have been suggested for vanilla as well as exotic options pricing. More of investing and hedging strategies have been developed based on these pricing models. Goal of this paper is to derive delta-gamma-theta hedging strategy for Asian options and compere its efficiency with gamma-delta-theta hedging combined with predictive model. Fixed strike Asian options are type of exotic options, whose special feature is that payoff is calculated from the difference of average market price and strike price for call options and vice versa for the put options. Methods of stochastic analysis are used to determine deltas, gammas and thetas of Asian options. Asian options are cheaper than vanilla options and therefore they are more suitable for precise portfolio creation. On the other hand their deltas are also smaller as well as profits. That means that they are also less risky and more suitable for hedging. Results, conducted on chosen commodity, confirm better feasibility of Asian options compering with vanilla options in sense of gamma hedging.

Further Evidence on Hedge Funds Performance

DEFF Research Database (Denmark)

Christiansen, Claus Bang; Madsen, Peter Brink; Christensen, Michael

2003-01-01

In this analysis we identify dynamic hedge fund strategies quantitatively pursuing a Principal Component Analysis following Fung and Hsieh (1997). We extract five dominant hedge fund strategies each representing similar investment styles and analyse the performance of each strategy by employing...... a multi-factor model comprising both market indices and passive option strategies among the lines of Agerwal and Naik (2000). We find that the majority of five homogenous strategies show superior performance. However, correcting for survivorship bias this superior performance disappears....

Differences between urban and rural hedges in England revealed by a citizen science project.

Science.gov (United States)

Gosling, Laura; Sparks, Tim H; Araya, Yoseph; Harvey, Martin; Ansine, Janice

2016-07-22

Hedges are both ecologically and culturally important and are a distinctive feature of the British landscape. However the overall length of hedges across Great Britain is decreasing. Current challenges in studying hedges relate to the dominance of research on rural, as opposed to urban, hedges, and their variability and geographical breadth. To help address these challenges and to educate the public on the importance of hedge habitats for wildlife, in 2010 the Open Air Laboratories (OPAL) programme coordinated a hedge-focused citizen science survey. Results from 2891 surveys were analysed. Woody plant species differed significantly between urban and rural areas. Beech, Holly, Ivy, Laurel, Privet and Yew were more commonly recorded in urban hedges whereas Blackthorn, Bramble, Dog Rose, Elder and Hawthorn were recorded more often in rural hedges. Urban and rural differences were shown for some groups of invertebrates. Ants, earwigs and shieldbugs were recorded more frequently in urban hedges whereas blowflies, caterpillars, harvestmen, other beetles, spiders and weevils were recorded more frequently in rural hedges. Spiders were the most frequently recorded invertebrate across all surveys. The presence of hard surfaces adjacent to the hedge was influential on hedge structure, number and diversity of plant species, amount of food available for wildlife and invertebrate number and diversity. In urban hedges with one adjacent hard surface, the food available for wildlife was significantly reduced and in rural hedges, one adjacent hard surface affected the diversity of invertebrates. This research highlights that urban hedges may be important habitats for wildlife and that hard surfaces may have an impact on both the number and diversity of plant species and the number and diversity of invertebrates. This study demonstrates that citizen science programmes that focus on hedge surveillance can work and have the added benefit of educating the public on the importance of

Strips of hourly power options. Approximate hedging using average-based forward contracts

International Nuclear Information System (INIS)

Lindell, Andreas; Raab, Mikael

2009-01-01

We study approximate hedging strategies for a contingent claim consisting of a strip of independent hourly power options. The payoff of the contingent claim is a sum of the contributing hourly payoffs. As there is no forward market for specific hours, the fundamental problem is to find a reasonable hedge using exchange-traded forward contracts, e.g. average-based monthly contracts. The main result is a simple dynamic hedging strategy that reduces a significant part of the variance. The idea is to decompose the contingent claim into mathematically tractable components and to use empirical estimations to derive hedging deltas. Two benefits of the method are that the technique easily extends to more complex power derivatives and that only a few parameters need to be estimated. The hedging strategy based on the decomposition technique is compared with dynamic delta hedging strategies based on local minimum variance hedging, using a correlated traded asset. (author)

Hedging local volume risk using forward markets: Nordic case

DEFF Research Database (Denmark)

Ernstsen, Rune Ramsdal; Boomsma, Trine Krogh; Tegner, Martin

2017-01-01

With focus on the Nordic electricity market, this paper develops hedging strategies for an electricity distributor who manages price and volume risk from fixed price agreements on stochastic electricity load. Whereas the distributor trades in the spot market at area prices, the financial contracts......, and we suggest various strategies for hedging in the presence of local volume risk. We benchmark against a strategy that ignores correlation and hedges at expected load, as is common practice in the industry. Using data from 2013 and 2014 for two Danish bidding areas, we show that our best hedging...... strategy reduces gross loss by 5.8% and 13.6% and increases gross profit by 3.8% and 9.5%, respectively. Although this is partly due to the inclusion of correlation, we show that performance improvement is mainly driven by the choice of risk measure....

Do Hedge Funds Manipulate Stock Prices?

OpenAIRE

Ben-David, Itzhak; Franzoni, Francesco; Landier, Augustin; Moussawi, Rabih

2011-01-01

We find evidence of significant price manipulation at the stock level by hedge funds on critical reporting dates. Stocks in the top quartile by hedge fund holdings exhibit abnormal returns of 30 basis points in the last day of the month and a reversal of 25 basis points in the following day. Using intraday data, we show that a significant part of the return is earned during the last minutes of the last day of the month, at an increasing rate towards the closing bell. This evidence is consiste...

A Two-Step Approach for Analytical Optimal Hedging with Two Triggers

Directory of Open Access Journals (Sweden)

Tiesong Hu

2016-02-01

Full Text Available Hedging is widely used to mitigate severe water shortages in the operation of reservoirs during droughts. Rationing is usually instituted with one hedging policy, which is based only on one trigger, i.e., initial storage level or current water availability. It may perform poorly in balancing the benefits of a release during the current period versus those of carryover storage during future droughts. This study proposes a novel hedging rule to improve the efficiency of a reservoir operated to supply water, in which, based on two triggers, hedging is initiated with three different hedging sub-rules through a two-step approach. In the first step, the sub-rule is triggered based on the relationship between the initial reservoir storage level and the level of the target rule curve or the firm rule curve at the end of the current period. This step is mainly concerned with increasing the water level or not in the current period. Hedging is then triggered under the sub-rule based on current water availability in the second step, in which the trigger implicitly considers both initial and ending reservoir storage levels in the current period. Moreover, the amount of hedging is analytically derived based on the Karush–Kuhn–Tucker (KKT conditions. In addition, the hedging parameters are optimized using the improved particle swarm optimization (IPSO algorithm coupled with a rule-based simulation. A single water-supply reservoir located in Hubei Province in central China is selected as a case study. The operation results show that the proposed rule is reasonable and significantly improves the reservoir operation performance for both long-term and critical periods relative to other operation policies, such as the standard operating policy (SOP and the most commonly used hedging rules.

Conservative Delta Hedging

Science.gov (United States)

1997-09-01

an exact method for converting such intervals into arbitrage based prices of financial derivatives or industrial or contractual options. We call this...procedure conservative delta hedging . As existing procedures are of an ad hoc nature, the proposed approach will permit an institution’s man agement a greater oversight of its exposure to risk.

Downside Risk analysis applied to the Hedge Funds universe

Science.gov (United States)

Perelló, Josep

2007-09-01

Hedge Funds are considered as one of the portfolio management sectors which shows a fastest growing for the past decade. An optimal Hedge Fund management requires an appropriate risk metrics. The classic CAPM theory and its Ratio Sharpe fail to capture some crucial aspects due to the strong non-Gaussian character of Hedge Funds statistics. A possible way out to this problem while keeping the CAPM simplicity is the so-called Downside Risk analysis. One important benefit lies in distinguishing between good and bad returns, that is: returns greater or lower than investor's goal. We revisit most popular Downside Risk indicators and provide new analytical results on them. We compute these measures by taking the Credit Suisse/Tremont Investable Hedge Fund Index Data and with the Gaussian case as a benchmark. In this way, an unusual transversal lecture of the existing Downside Risk measures is provided.

Adaptive control system having hedge unit and related apparatus and methods

Science.gov (United States)

Johnson, Eric Norman (Inventor); Calise, Anthony J. (Inventor)

2007-01-01

The invention includes an adaptive control system used to control a plant. The adaptive control system includes a hedge unit that receives at least one control signal and a plant state signal. The hedge unit generates a hedge signal based on the control signal, the plant state signal, and a hedge model including a first model having one or more characteristics to which the adaptive control system is not to adapt, and a second model not having the characteristic(s) to which the adaptive control system is not to adapt. The hedge signal is used in the adaptive control system to remove the effect of the characteristic from a signal supplied to an adaptation law unit of the adaptive control system so that the adaptive control system does not adapt to the characteristic in controlling the plant.

A Behavioral Decision Making Modeling Approach Towards Hedging Services

NARCIS (Netherlands)

Pennings, J.M.E.; Candel, M.J.J.M.; Egelkraut, T.M.

2003-01-01

This paper takes a behavioral approach toward the market for hedging services. A behavioral decision-making model is developed that provides insight into how and why owner-managers decide the way they do regarding hedging services. Insight into those choice processes reveals information needed by

Hedging with futures contracts in the Brazilian soybean complex: BM&F vs. CBOT

Directory of Open Access Journals (Sweden)

Andréia Regina O. da Silva

2003-06-01

Full Text Available This article analyzes the effectiveness of hedging Brazilian soy oil, soy meal, and soybeans in the Chicago Board of Trade (CBOT and in the Brazilian Commodities and Futures Exchange (BM&F to reduce the risk of financial loss due to commodity price fluctuations. The econometric results show that a cross-hedging strategy using the BM&F soybean futures contract is an instrument of low effectiveness for managing soy oil and soy meal price risk. Despite low effectiveness, the estimates demonstrate total advantage for soy meal hedging operations using CBOT soy meal futures contracts rather than cross-hedging using BM&F soybean futures contracts. With some exceptions, the results are also more favorable for hedging soy oil with soy oil futures contracts at the CBOT rather than cross hedging with soybeans at the BM&F. Conversely, Brazilian traders hedging soybeans receive more effective risk protection by trading soybean futures contracts at the BM&F than by trading soybean futures contracts at the CBOT.

Fundamentals and advanced techniques in derivatives hedging

CERN Document Server

Bouchard, Bruno

2016-01-01

This book covers the theory of derivatives pricing and hedging as well as techniques used in mathematical finance. The authors use a top-down approach, starting with fundamentals before moving to applications, and present theoretical developments alongside various exercises, providing many examples of practical interest. A large spectrum of concepts and mathematical tools that are usually found in separate monographs are presented here. In addition to the no-arbitrage theory in full generality, this book also explores models and practical hedging and pricing issues. Fundamentals and Advanced Techniques in Derivatives Hedging further introduces advanced methods in probability and analysis, including Malliavin calculus and the theory of viscosity solutions, as well as the recent theory of stochastic targets and its use in risk management, making it the first textbook covering this topic. Graduate students in applied mathematics with an understanding of probability theory and stochastic calculus will find this b...

Estratégias de hedge com os contratos futuros de soja da Chicago Board of Trade Hedging strategies with Chicago Board of Trade soybeans futures contracts

Directory of Open Access Journals (Sweden)

Fábio Neves de Carvalho da Silva Maia

2010-01-01

Full Text Available Este trabalho avalia os retornos e os riscos de estratégias de hedge para as dez principais regiões produtoras de soja do Brasil em relação aos contratos futuros de soja da Chicago Board of Trade (CBOT. Verificou-se que as bases apresentaram padrão bem definido: fortalecimento entre maio e novembro, seguido por enfraquecimento nos seis meses subsequentes. Os hedgers de compra possuem oportunidades de obter retornos brutos maiores, mas os riscos envolvidos nas estratégias de hedge de compra também são maiores. Conclui-se que os contratos de soja em grão da CBOT apresentam diferentes possibilidades de retornos brutos em função do tipo de hedge, do período hedgeado e do contrato utilizado. Logo, as informações disponibilizadas neste trabalho se apresentam como importante subsídio ao processo de tomada de decisão por parte dos agentes da cadeia agroindustrial da soja.This paper analyzes the return and risks of hedging strategies of the major ten soybean producing regions in Brazil concerning Chicago Board of Trade (CBOT future contracts. It was verified that the bases presented a well defined pattern characterized by strengthening from May to November and weakening in the remaining months. Long hedging had larger returns and larger risks comparing with short hedging. The conclusion of this study is that the CBOT soybean contracts present different returns depending on the type of hedging, on the period of hedging, and on the contract used. Therefore, the information presented in this paper is very important to support the decision making process in the Brazilian soybean agricultural system.

Determining the multi-scale hedge ratios of stock index futures using the lower partial moments method

Science.gov (United States)

Dai, Jun; Zhou, Haigang; Zhao, Shaoquan

2017-01-01

This paper considers a multi-scale future hedge strategy that minimizes lower partial moments (LPM). To do this, wavelet analysis is adopted to decompose time series data into different components. Next, different parametric estimation methods with known distributions are applied to calculate the LPM of hedged portfolios, which is the key to determining multi-scale hedge ratios over different time scales. Then these parametric methods are compared with the prevailing nonparametric kernel metric method. Empirical results indicate that in the China Securities Index 300 (CSI 300) index futures and spot markets, hedge ratios and hedge efficiency estimated by the nonparametric kernel metric method are inferior to those estimated by parametric hedging model based on the features of sequence distributions. In addition, if minimum-LPM is selected as a hedge target, the hedging periods, degree of risk aversion, and target returns can affect the multi-scale hedge ratios and hedge efficiency, respectively.

A risk reserve model for hedging in incomplete markets

NARCIS (Netherlands)

Minina, V.; Vellekoop, M.

2010-01-01

This paper presents a new approach to the pricing and hedging problem for contingent claims in incomplete markets. We assume that traders wish to maximize the expected final payoff of the hedging portfolio and the claims, and we avoid the use of utility functions. Instead, we model how traders are

Hedging in Popular Scientific Articles on Medicine

Directory of Open Access Journals (Sweden)

Csongor Alexandra

2013-04-01

Full Text Available Introduction: The aim of this study is to investigate the process of rewriting medical research papers for the lay public. The latest findings of medical research often appear in the popular media. It is interesting to see what happens to a scientific text when it is transmitted to a new audience. Hedging is usually interpreted as a characteristic feature of scientific discourse. This study focuses on hedging, which also tends to be applied in popularized articles in the field of medicine.

Evaluation of different hedging strategies for commodity price risks of industrial cogeneration plants

International Nuclear Information System (INIS)

Palzer, Andreas; Westner, Günther; Madlener, Reinhard

2013-01-01

In this paper, we design and evaluate eight different strategies for hedging commodity price risks of industrial cogeneration plants. Price developments are parameterized based on EEX data from 2008 to 2011. The probability distributions derived are used to determine the value-at-risk (VaR) of the individual strategies, which are in a final step combined in a mean-variance portfolio analysis for determining the most efficient hedging strategy. We find that the strategy adopted can have a marked influence on the remaining price risk. Quarter futures are found to be particularly well suited for reducing market price risk. In contrast, spot trading of CO 2 certificates is found to be preferable compared to forward market trading. Finally, portfolio optimization shows that a mix of various hedging strategies can further improve the profitability of a heat-based cogeneration plant. - Highlights: • Evaluation of commodity price risk hedging strategies for industrial cogeneration. • Value-at-risk analysis of eight different hedging strategies. • Mean-variance portfolio analysis for determining the optimal hedging strategy mix. • A mix of hedging strategies further improves profitability of heat-based CHP

Hedge Fund Stock Trading in the Financial Crisis of 2007--2009

OpenAIRE

Itzhak Ben-David; Francesco Franzoni; Rabih Moussawi

2012-01-01

Hedge funds significantly reduced their equity holdings during the recent financial crisis. In 2008:Q3----Q4, hedge funds sold about 29% of their aggregate portfolio. Redemptions and margin calls were the primary drivers of selloffs. Consistent with forced deleveraging, the selloffs took place in volatile and liquid stocks. In comparison, redemptions and stock sales for mutual funds were not as severe. We show that hedge fund investors withdraw capital three times as intensely as mutual fund ...

Hedging with futures: an application of GARCH to european electricity markets

OpenAIRE

G. Zanotti; G. Gabbi; M. Geranio

2009-01-01

European electricity markets have been subject to a broad deregulation process in the last few decades. We analyse hedging policies implemented through different hedge ratios estimation. More specifically we compare naïve, ordinary least squares, and GARCH conditional variance and correlations models to test if GARCH models lead to higher variance reduction in a context of high time varying volatility as the case of electricity markets. Our results show that the choice of the hedge ratio esti...

Are "Market Neutral" Hedge Funds Really Market Neutral?

OpenAIRE

Andrew J. Patton

2009-01-01

Using a variety of different definitions of "neutrality," this study presents significant evidence against the neutrality to market risk of hedge funds in a range of style categories. I generalize standard definitions of "market neutrality," and propose five different neutrality concepts. I suggest statistical tests for each neutrality concept, and apply these tests to a database of monthly returns on 1423 hedge funds from five style categories. For the "market neutral" style, approximately o...

Effect of reservoir zones and hedging factor dynamism on reservoir adaptive capacity for climate change impacts

Science.gov (United States)

Adeloye, Adebayo J.; Soundharajan, Bankaru-Swamy

2018-06-01

When based on the zones of available water in storage, hedging has traditionally used a single hedged zone and a constant rationing ratio for constraining supply during droughts. Given the usual seasonality of reservoir inflows, it is also possible that hedging could feature multiple hedged zones and temporally varying rationing ratios but very few studies addressing this have been reported especially in relation to adaptation to projected climate change. This study developed and tested Genetic Algorithms (GA) optimised zone-based operating policies of various configurations using data for the Pong reservoir, Himachal Pradesh, India. The results show that hedging does lessen vulnerability, which dropped from ≥ 60 % without hedging to below 25 % with the single stage hedging. More complex hedging policies, e.g. two stage and/or temporally varying rationing ratios only produced marginal improvements in performance. All this shows that water hedging policies do not have to be overly complex to effectively offset reservoir vulnerability caused by water shortage resulting from e.g. projected climate change.

Dynamically Hedging Oil and Currency Futures Using Receding Horizontal Control and Stochastic Programming

Science.gov (United States)

Cottrell, Paul Edward

There is a lack of research in the area of hedging future contracts, especially in illiquid or very volatile market conditions. It is important to understand the volatility of the oil and currency markets because reduced fluctuations in these markets could lead to better hedging performance. This study compared different hedging methods by using a hedging error metric, supplementing the Receding Horizontal Control and Stochastic Programming (RHCSP) method by utilizing the London Interbank Offered Rate with the Levy process. The RHCSP hedging method was investigated to determine if improved hedging error was accomplished compared to the Black-Scholes, Leland, and Whalley and Wilmott methods when applied on simulated, oil, and currency futures markets. A modified RHCSP method was also investigated to determine if this method could significantly reduce hedging error under extreme market illiquidity conditions when applied on simulated, oil, and currency futures markets. This quantitative study used chaos theory and emergence for its theoretical foundation. An experimental research method was utilized for this study with a sample size of 506 hedging errors pertaining to historical and simulation data. The historical data were from January 1, 2005 through December 31, 2012. The modified RHCSP method was found to significantly reduce hedging error for the oil and currency market futures by the use of a 2-way ANOVA with a t test and post hoc Tukey test. This study promotes positive social change by identifying better risk controls for investment portfolios and illustrating how to benefit from high volatility in markets. Economists, professional investment managers, and independent investors could benefit from the findings of this study.

How fair-value accounting can influence firm hedging

OpenAIRE

Beisland, Leif Atle; Frestad, Dennis

2013-01-01

Published version of an article in the journal: Review of Derivatives Research. Also available from the publisher at: http://dx.doi.org/10.1007/s11147-012-9084-y The potential influence of accounting regulations on hedging strategies and the use of financial derivatives is a research topic that has attracted little attention in both the finance and the accounting literature. However, recent surveys suggest that company hedging can be substantially influenced by the accounting for financial...

Pricing and Hedging of Derivatives in Contagious Markets

DEFF Research Database (Denmark)

Kokholm, Thomas

2016-01-01

It is well documented that stock markets are contagious. A negative shock to one market increases the probability of adverse shocks to other markets. We model this contagion effect by including mutually exciting jump processes in the dynamics of the indexes' log-returns. On top of this we add...... a stochastic volatility component to the dynamics. It is important to take the contagion effect into account if derivatives written on a basket of assets are to be priced or hedged. Due to the affine model specification the joint characteristic function of the log-returns is known analytically, and for two......-asset derivatives prices and show how for certain derivatives the impact is heavy. Moreover, we derive hedge ratios for European put and call options and perform a numerical experiment, which illustrates the impact of contagious jumps on option prices and hedge ratios. Mutually exciting processes have been analyzed...

Highwaymen or heroes: should hedge funds be regulated?

OpenAIRE

Jon Danielsson; Ashley Taylor; Jean-Pierre Zigrand

2004-01-01

The exponential growth of hedge funds, their role in financial crises in the 1990s, and examples of fraudulent behaviour have precipitated a heated debate over their regulatory status. The existing approaches of greater disclosure and activity restrictions appear too blunt to be effective and may stifle the benefits hedge funds can bring to the financial system. But, even the remote possibility of a systemic crisis weighs against no regulation. If reform is delayed until after a crisis it is ...

Hedging strategies for petroleum companies; Estrategias de hedging para empresas de petroleo

Energy Technology Data Exchange (ETDEWEB)

Cohen, Joaquim Dib [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2004-07-01

The prices of crude oil and products in the international market are becoming more and more volatile putting in risk the investment plans of the Oil Companies, their commercial revenues and even their survival. From 1983, with the launch of the WTI crude contract at the New York Mercantile Exchange (NYMEX), the market for derivatives had been growing at very high rate, letting the Companies to use it in order to protect their positions (hedging) and minimizing their business exposure to price risk. The Over the Counter (OTC) market, leaded by Financial Institutions, together with the exchange, are bringing a sort of different strategies to allow producers to protect their portfolios against an adverse move of the market, traders and refiners can, also, fix their margins and guarantee their profitability and, finally, end users are entitle to freeze their feedstock and keep their market competitiveness. Thus, producers, refiners, traders and end users of petroleum and products, have more and more take advantage of the use of derivatives to make their business foreseeable and profitable choosing the risk level they want to take by using a combination of market derivative hedging strategies as shown in this paper. (author)

Minimal variance hedging of natural gas derivatives in exponential Lévy models: Theory and empirical performance

International Nuclear Information System (INIS)

Ewald, Christian-Oliver; Nawar, Roy; Siu, Tak Kuen

2013-01-01

We consider the problem of hedging European options written on natural gas futures, in a market where prices of traded assets exhibit jumps, by trading in the underlying asset. We provide a general expression for the hedging strategy which minimizes the variance of the terminal hedging error, in terms of stochastic integral representations of the payoffs of the options involved. This formula is then applied to compute hedge ratios for common options in various models with jumps, leading to easily computable expressions. As a benchmark we take the standard Black–Scholes and Merton delta hedges. We show that in natural gas option markets minimal variance hedging with underlying consistently outperform the benchmarks by quite a margin. - Highlights: ► We derive hedging strategies for European type options written on natural gas futures. ► These are tested empirically using Henry Hub natural gas futures and options data. ► We find that our hedges systematically outperform classical benchmarks

Hedging effectiveness and volatility models for crude oil market: a dynamic approach; Modelos de volatilidade e a efetividade do hedge no mercado de petroleo: um abordagem dinamica

Energy Technology Data Exchange (ETDEWEB)

Salles, Andre Assis de [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

2012-07-01

The hedge strategies allow negotiators that have short and long positions in the market protection against price fluctuations. This paper examines the performance of bivariate volatility models for the crude oil spot and future returns of the Western Texas Intermediate - WTI type barrel prices. Besides the volatility of spot and future crude oil barrel returns time series, the hedge ratio strategy is examined through the hedge effectiveness. Thus this study shows hedge strategies built using methodologies applied in the variance modeling of returns of crude oil prices in the spot and future markets, and covariance between these two market returns, which correspond to the inputs of the hedge strategy shown in this work. From the studied models the bivariate GARCH in a Diagonal VECH and BEKK representations was chosen, using three different models for the mean: a bivariate autoregressive, a vector autoregressive and a vector error correction. The methodologies used here take into consideration the denial of assumptions of homoscedasticity and normality for the return distributions. The data used is logarithm returns of daily prices quoted in dollars per barrel from November 2008 to May 2010 for spot and future contracts, in particular the June contract. (author)

18 CFR 367.2450 - Account 245, Derivative instrument liabilities-Hedges

Science.gov (United States)

2010-04-01

..., Derivative instrument liabilities—Hedges (a) This account must include the change in the fair value of... service company must record the change in the fair value of a derivative instrument liability related to a... change in the fair value of a derivative instrument liability related to a fair value hedge in this...

Hedging Rules for Water Supply Reservoir Based on the Model of Simulation and Optimization

Directory of Open Access Journals (Sweden)

Yi Ji

2016-06-01

Full Text Available This study proposes a hedging rule model which is composed of a two-period reservior operation model considering the damage depth and hedging rule parameter optimization model. The former solves hedging rules based on a given poriod’s water supply weighting factor and carryover storage target, while the latter optimization model is used to optimize the weighting factor and carryover storage target based on the hedging rules. The coupling model gives the optimal poriod’s water supply weighting factor and carryover storage target to guide release. The conclusions achieved from this study as follows: (1 the water supply weighting factor and carryover storage target have a direct impact on the three elements of the hedging rule; (2 parameters can guide reservoirs to supply water reasonably after optimization of the simulation and optimization model; and (3 in order to verify the utility of the hedging rule, the Heiquan reservoir is used as a case study and particle swarm optimization algorithm with a simulation model is adopted for optimizing the parameter. The results show that the proposed hedging rule can improve the operation performances of the water supply reservoir.

Risk Management Framework for Hedge Funds: Role of Funding and Redemption Options on Leverage

OpenAIRE

Dai, John; Sundaresan, Suresh

2009-01-01

We develop a model of hedge fund returns, which reflect the contractual relationships between a hedge fund, its investors and its prime brokers. These relationships are modelled as short option positions held by the hedge fund, wherein the “funding option” reflects the short option position with prime brokers and the “redemption option” reflects the short option position with the investors. Given an alpha producing human capital, the hedge fund’s ability to deploy leverage to magnify its alph...

Hedge math: Theoretical limits on minimum stockpile size across nuclear hedging strategies

Energy Technology Data Exchange (ETDEWEB)

Lafleur, Jarret Marshall [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Roesler, Alexander W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-09-01

In June 2013, the Department of Defense published a congressionally mandated, unclassified update on the U.S. Nuclear Employment Strategy. Among the many updates in this document are three key ground rules for guiding the sizing of the non-deployed U.S. nuclear stockpile. Furthermore, these ground rules form an important and objective set of criteria against which potential future stockpile hedging strategies can be evaluated.

Electricity market pricing, risk hedging and modeling

Science.gov (United States)

Cheng, Xu

In this dissertation, we investigate the pricing, price risk hedging/arbitrage, and simplified system modeling for a centralized LMP-based electricity market. In an LMP-based market model, the full AC power flow model and the DC power flow model are most widely used to represent the transmission system. We investigate the differences of dispatching results, congestion pattern, and LMPs for the two power flow models. An appropriate LMP decomposition scheme to quantify the marginal costs of the congestion and real power losses is critical for the implementation of financial risk hedging markets. However, the traditional LMP decomposition heavily depends on the slack bus selection. In this dissertation we propose a slack-independent scheme to break LMP down into energy, congestion, and marginal loss components by analyzing the actual marginal cost of each bus at the optimal solution point. The physical and economic meanings of the marginal effect at each bus provide accurate price information for both congestion and losses, and thus the slack-dependency of the traditional scheme is eliminated. With electricity priced at the margin instead of the average value, the market operator typically collects more revenue from power sellers than that paid to power buyers. According to the LMP decomposition results, the revenue surplus is then divided into two parts: congestion charge surplus and marginal loss revenue surplus. We apply the LMP decomposition results to the financial tools, such as financial transmission right (FTR) and loss hedging right (LHR), which have been introduced to hedge against price risks associated to congestion and losses, to construct a full price risk hedging portfolio. The two-settlement market structure and the introduction of financial tools inevitably create market manipulation opportunities. We investigate several possible market manipulation behaviors by virtual bidding and propose a market monitor approach to identify and quantify such

A risk hedging strategy under the nonparallel-shift yield curve

Science.gov (United States)

Gong, Pu; He, Xubiao

2005-08-01

Under the assumption of the movement of rigid, a nonparallel-shift model in the term structure of interest rates is developed by introducing Fisher & Weil duration which is a well-known concept in the area of interest risk management. This paper has studied the hedge and replication for portfolio immunization to minimize the risk exposure. Throughout the experiment of numerical simulation, the risk exposures of the portfolio under the different risk hedging strategies are quantitatively evaluated by the method of value at risk (VaR) order statistics (OS) estimation. The results show that the risk hedging strategy proposed in this paper is very effective for the interest risk management of the default-free bond.

MEANING-MAKING OF HEDGES IN THE GOSSIP COLUMN OF THE JAKARTA POST

Directory of Open Access Journals (Sweden)

Uswatun Hasanah

2016-01-01

Full Text Available The present study investigates the use of hedges (vague language as the meaning-making practice in the gossip column of the Jakarta Post. The daily newspaper is chosen due to pragmatic purposes, accessibility, and its national coverage. Adapting the framework of Lakoff (1973, Holmes (1990 and Hyland (1996a-b, this study focuses on the hedges’ functions and meanings in a gossip column (informal context, apart from an academic discourse (formal context in which hedges are frequently discussed. This possibly leads to the diverse functions and meanings of the hedges’ occurrences within the discourse: through the employment of ‘epistemic modal’ (the expression of uncertainty and ‘affective’ (the expression of solidarity function. Further, the mostly-found hedges are the epistemic modal ‘about’ (five times and the affective modal ‘think’ (four times from six hedge categories. Eventually, it is also revealed that hedges used in the gossip column are to enhance the self-image and trend-setting identity of the celebrities, who indeed are involved in the discourse.

Using Derivatives to Hedge Interest Rate Risk: A Student Exercise

Science.gov (United States)

Donaldson, Jeff; Flagg, Donald

2014-01-01

In a world of fluctuating asset prices, many firms find the need to hedge in order to avoid or reduce losses. From a gold miner selling gold derivatives to airlines buying oil futures to protect against rising fuel costs, hedging is common practice across many different industries. In this paper, we provide students with a simplified example of a…

Delayed bet-hedging resilience strategies under environmental fluctuations

Science.gov (United States)

Ogura, Masaki; Wakaiki, Masashi; Rubin, Harvey; Preciado, Victor M.

2017-05-01

Many biological populations, such as bacterial colonies, have developed through evolution a protection mechanism, called bet hedging, to increase their probability of survival under stressful environmental fluctuation. In this context, the concept of preadaptation refers to a common type of bet-hedging protection strategy in which a relatively small number of individuals in a population stochastically switch their phenotypes to a dormant metabolic state in which they increase their probability of survival against potential environmental shocks. Hence, if an environmental shock took place at some point in time, preadapted organisms would be better adapted to survive and proliferate once the shock is over. In many biological populations, the mechanisms of preadaptation and proliferation present delays whose influence in the fitness of the population are not well understood. In this paper, we propose a rigorous mathematical framework to analyze the role of delays in both preadaptation and proliferation mechanisms in the survival of biological populations, with an emphasis on bacterial colonies. Our theoretical framework allows us to analytically quantify the average growth rate of a bet-hedging bacterial colony with stochastically delayed reactions with arbitrary precision. We verify the accuracy of the proposed method by numerical simulations and conclude that the growth rate of a bet-hedging population shows a nontrivial dependency on their preadaptation and proliferation delays. Contrary to the current belief, our results show that faster reactions do not, in general, increase the overall fitness of a biological population.

Survival, Look-Ahead Bias and the Persistence in Hedge Fund Performance

NARCIS (Netherlands)

G. Baquero; J.R. ter Horst (Jenke); M.J.C.M. Verbeek (Marno)

2005-01-01

textabstractWe analyze the performance persistence in hedge funds taking into account look-ahead bias (multi-period sampling bias). We model liquidation of hedge funds by analyzing how it depends upon historical performance. Next, we use a weighting procedure that eliminates look-ahead bias in

Hedge Funds and Risk-Decoupling

DEFF Research Database (Denmark)

Ringe, Wolf-Georg

Negative risk-decoupling, otherwise known as empty voting, is a popular strategy amongst hedge funds and other activist investors. In short, it is the attempt to decouple the economic risk from the share’s ownership position, retaining in particular the voting right without risk. This paper uses ...

It Only Takes a Few Moments to Hedge

DEFF Research Database (Denmark)

Barletta, Andrea; Santucci de Magistris, Paolo; Pedersen, David Sloth

Traders hedge the risks carried by options and other securities using the so-called Greeks, with the delta and the vega being the most prominent. In this paper, we propose a novel non-structural method for hedging European options, relying on two model-independent results: First, under suitable...... in variance swap contracts or, indirectly, through an ATM call option. While both strategies ensure effective immunization in periods of market turmoil, taking direct exposure on volatility might not be optimal during extended periods of subdued market volatility. We argue that this result is related...

Crystallization: the hidden dimension of Hedge funds' fee structure

OpenAIRE

Elaut, Gert; Frömmel, Michael; Sjödin, John

2014-01-01

We investigate the implications of variations in the frequency with which hedge fund managers update their high-water mark on fees paid by investors. We first document the crystallization frequencies used by Commodity Trading Advisors (CTAs) and then perform simulations and a bootstrap analysis. We find a statistically and economically significant effect of the crystallization frequency on the total fee load. Hedge funds' total fee load increases significantly as the crystallization frequency...

Hedging Yield with Weather Derivatives: A Role for Options

OpenAIRE

Manfredo, Mark R.; Richards, Timothy J.

2005-01-01

While there are few risk management alternatives available to specialty crop growers, weather derivatives provide an important advancement. As with the use of any derivatives contract, the behavior of the basis will ultimately determine the net-hedged outcome. However, when using weather derivatives to hedge yield risks for specialty crops, growers face a unique form of basis risk because weather (temperature) and yield are nonlinearly related. Using the forecast encompassing principle, this ...

Robust facility location: Hedging against failures

International Nuclear Information System (INIS)

Hernandez, Ivan; Emmanuel Ramirez-Marquez, Jose; Rainwater, Chase; Pohl, Edward; Medal, Hugh

2014-01-01

While few companies would be willing to sacrifice day-to-day operations to hedge against disruptions, designing for robustness can yield solutions that perform well before and after failures have occurred. Through a multi-objective optimization approach this paper provides decision makers the option to trade-off total weighted distance before and after disruptions in the Facility Location Problem. Additionally, this approach allows decision makers to understand the impact on the opening of facilities on total distance and on system robustness (considering the system as the set of located facilities). This approach differs from previous studies in that hedging against failures is done without having to elicit facility failure probabilities concurrently without requiring the allocation of additional hardening/protections resources. The approach is applied to two datasets from the literature

Risk preference, option pricing and portfolio hedging with proportional transaction costs

International Nuclear Information System (INIS)

Wang, Xiao-Tian; Li, Zhe; Zhuang, Le

2017-01-01

Highlights: • Scaling is a key factor in option pricing. • The model is theoretically analyzed and the results are new. • Some numerical examples are performed. • The implied-volatility-frown is affected by the risk preference and scaling. - Abstract: This paper is concerned in the option pricing and portfolio hedging in a discrete time case with the proportional transaction costs. Through the Monte Carlo simulations it has been shown that the fractal scaling and risk preference of traders have an important influence on the hedging performances in both option pricing and portfolio hedging in a discrete time case. In addition, the relation between preference of traders and implied volatility frown is discussed. We conclude that the risk preferences of traders play an important role in determining the shape of the implied-volatility-frown and the different options having the different hedging frequencies is another reason for the implied volatility frown.

Gas Storage Valuation and Hedging: A Quantification of Model Risk

Directory of Open Access Journals (Sweden)

Patrick Hénaff

2018-03-01

Full Text Available This paper focuses on the valuation and hedging of gas storage facilities, using a spot-based valuation framework coupled with a financial hedging strategy implemented with futures contracts. The contributions of this paper are two-fold. Firstly, we propose a model that unifies the dynamics of the futures curve and spot price, and accounts for the main stylized facts of the US natural gas market such as seasonality and the presence of price spikes in the spot market. Secondly, we evaluate the associated model risk, and show not only that the valuation is strongly dependent upon the dynamics of the spot price, but more importantly that the hedging strategy commonly used in the industry leaves the storage operator with significant residual price risk.

Bet-hedging applications for conservation

Indian Academy of Sciences (India)

One of the early tenets of conservation biology is that population viability is enhanced by maintaining multiple populations of a species. The strength of this tenet is justified by principles of bet-hedging. Management strategies that reduce variance in population size will also reduce risk of extinction. Asynchrony in population ...

Hedging against terrorism: Are US businesses prepared?

Science.gov (United States)

Kahan, Jerome H

2015-01-01

Private US companies face risks in connection with financial matters, but are not necessarily prepared to cope with risks that can seriously disrupt or even halt their operations, notably terrorist attacks and natural disasters. Enhancing the resilience of businesses when dealing with terrorism is especially challenging, as these groups or individuals can adapt tactics to exploit the vulnerabilities of companies they wish to target. Business managers need to formulate flexible preparedness plans that reduce risks from large-scale natural disasters as well as terrorist attacks. In doing so, they can take advantage of post-9/11 US government guidance for these endeavours as well as programmes that eliminate risks to private insurance entities so they can issue policies that cover terrorist strikes of high consequences. Just as business executives use hedging strategies in the world of finance, they also need operational hedging strategies as a means of exploiting as well as lowering the risks surrounding future uncertainties. Resources devoted to planning and hedging are investments that can increase the odds of businesses surviving and thriving, even if they experience high-impact terrorist attacks, threats or large-scale natural disasters, making suppliers, customers and stakeholders happy. The purpose of this paper is to give executives the incentive to take steps to do just that.

Speculative and hedging activities in the European carbon market

International Nuclear Information System (INIS)

Lucia, Julio J.; Mansanet-Bataller, Maria; Pardo, Ángel

2015-01-01

We explore the dynamics of the speculative and hedging activities in European futures carbon markets by using volume and open interest data. A comparison of the three phases in the European Union Emission Trading Scheme (EU ETS) reveals that (i) Phase II of the EU ETS seems to be the most speculative phase to date and (ii) the highest degree of speculative activity for every single phase occurs at the moment of listing the contracts for the first time. A seasonality analysis identifies a higher level of speculation in the first quarter of each year, related to the schedule of deadlines of the EU ETS. In addition, a time series analysis confirms that most of the speculative activity each year occurs in the front contract, whereas the hedging demand concentrates in the second-to-deliver futures contract. -- Highlights: •This study explores the evolution of speculative and hedging activities in futures carbon markets by using volume and open interest data. •Phase II of the EU ETS seems to be the most speculative phase to date. •A seasonality analysis identifies a higher level of speculation in the first quarter of each year. •Most of the speculative activity occurs in the front contract. •The hedging demand concentrates in the second-to-deliver futures contract

Hedge Effectiveness in the Brazilian US Dollar Futures Market

Directory of Open Access Journals (Sweden)

Leonardo Lima Gomes

2011-09-01

Full Text Available In recent years, one could observe a very definite surge in dollar prices in Brazil. Many Brazilian Companies, especially those with large amounts of dollar denominated debt incurred substantial losses due to the strong and fast growth of the dollar. The subsequent dollar price collapse from 2002 to 2008 caused great losses to exporters. In the context of hedge being a form of protection against currency oscillations, this paper aimed to study its effectiveness using the dollar future market in the BM&FBovespa. Specifically, four alternatives for calculating the optimum hedge ratio were compared: a the so called naïve approach, where opposite positions are taken in the spot and future markets; b OLS – Ordinary Least Squares c symmetric bi-variate GARCH (Generalized Autoregressive Conditional Heteroscedasticity; d asymmetric bi-variate GARCH. The results showed that both GARCH supported hedge ratios presented higher effectiveness when compared to OLS, with in turn surpassed the naïve one.

On Mean-Variance Hedging of Bond Options with Stochastic Risk Premium Factor

NARCIS (Netherlands)

Aihara, ShinIchi; Bagchi, Arunabha; Kumar, Suresh K.

2014-01-01

We consider the mean-variance hedging problem for pricing bond options using the yield curve as the observation. The model considered contains infinite-dimensional noise sources with the stochastically- varying risk premium. Hence our model is incomplete. We consider mean-variance hedging under the

Currency hedging with help of derivatives

Directory of Open Access Journals (Sweden)

Sylvie Riederová

2011-01-01

Full Text Available The high volatility combined with unpredictable fluctuations of CZK had shown one more time to the Czech exporting companies the necessity of currency hedging. This article is focused on finding of suitable currency hedging instrument for exporting company, working with the currency pair of CZK/EUR. In the first part, the time series analysis is made for volatility, interest rates and exchange rate. Based on the real market data – gained from Thomson REUTERS and CNB for the time period starting in 2002 – the detailed analysis is made in graphical form. The main goal is to find out the future trends with help of liner regression analysis, based on the historical data. Several graphs are provided with the trend line end estimated interval (min and max for the each variable. The calculated values are clearly marked, to be separated from the real market data. Exchange rate curve shows the market behaviour in the last years and is to be used as most important indicator for the future trends. Interest rates curves are very important for the calculation of the BIPS (basis points, determining the price of the forwards. The difference between landing and deposit rates for the same period of time and different currencies are showing the market estimation of the future development of each currency. Forward price is to be seen as a benchmark for the all other financial instruments. And finally the volatility (quoted as middle is very important part in the pricing of currency options.The second part is closely connected with the first one. Based on the results of provided analyses, it recommends a suitable hedging product for the next period of time. All of the analyses are taken as an input in different ways. The volatility is important for the decision of selling or purchasing the specific part of currency option. The exchange rate outlook together with the interest rates is the indicator of the future development of the currency pair and is playing

E-Commerce and Exchange Rate Exposure Management: A Tilt towards Real Hedging

DEFF Research Database (Denmark)

Aabo, Tom

2001-01-01

The aim of this paper is to address the impact of E-commerce on the balance between real hedging and financial hedging in the context of exchange rate exposure management in non-financial companies. A cross-case study of industrial companies highlights the inadequacy in taking a partial and static...... financial approach when managing exchange rate exposures. The paper argues that the emergence of E-commerce - by reducing the cost of obtaining, analyzing and allocating information - affects the dynamics of the markets and the dynamics of the company in such a way that a general tilt towards real hedging...

Assessing Performance of Multipurpose Reservoir System Using Two-Point Linear Hedging Rule

Science.gov (United States)

Sasireka, K.; Neelakantan, T. R.

2017-07-01

Reservoir operation is the one of the important filed of water resource management. Innovative techniques in water resource management are focussed at optimizing the available water and in decreasing the environmental impact of water utilization on the natural environment. In the operation of multi reservoir system, efficient regulation of the release to satisfy the demand for various purpose like domestic, irrigation and hydropower can lead to increase the benefit from the reservoir as well as significantly reduces the damage due to floods. Hedging rule is one of the emerging techniques in reservoir operation, which reduce the severity of drought by accepting number of smaller shortages. The key objective of this paper is to maximize the minimum power production and improve the reliability of water supply for municipal and irrigation purpose by using hedging rule. In this paper, Type II two-point linear hedging rule is attempted to improve the operation of Bargi reservoir in the Narmada basin in India. The results obtained from simulation of hedging rule is compared with results from Standard Operating Policy, the result shows that the application of hedging rule significantly improved the reliability of water supply and reliability of irrigation release and firm power production.

Currency Hedging for International Stock Portfolios

NARCIS (Netherlands)

F.A. de Roon (Frans); T.E. Nijman (Theo); B.J.M. Werker

2000-01-01

textabstractThis paper tests whether hedging currency risk improves the performance of international stock portfolios. We use a generalized performance measure which allows for investor-dependencies such as different utility functions and the presence of nontraded risks. In addition we show that an

Double hedge aids commercial terms of upstream asset purchase

International Nuclear Information System (INIS)

Wood, D.

1993-01-01

In recent years many major oil companies have elected to rationalize their producing assets. Mature production--particularly onshore in developed countries, associated with high costs and small profit margins--has been the major target. The current weakness in oil prices has resulted in many such properties being on the market. However, much production marginal to a major can be highly profitable to a cost-effective independent, particularly if the production fits strategically with the independent's asset portfolio. Although many independents recognize that some of the producing assets on the market could be of potential value to them, in a period of volatile prices two important valuations have to be technically justified and negotiated to enable or persuade them to conclude a purchase agreement for a specific asset. These are: A purchase value for an asset that is acceptable to both seller and buyer; and A loan value for the asset to establish the level of debt that the asset can support for the buyer. In defining these two important values (both of which are usually established as ranges rather than single values) the independent has to protect itself against a downturn in commodity prices and exposing itself to an unserviceable level of debt. The paper discusses reducing risks, purchase price hedge, an example of a hedged purchase price, price elements, loan value analysis, agreement structure, loan value hedge, and an example of a hedged loan value

A model for hedging load and price risk in the Texas electricity market

International Nuclear Information System (INIS)

Coulon, Michael; Powell, Warren B.; Sircar, Ronnie

2013-01-01

Energy companies with commitments to meet customers' daily electricity demands face the problem of hedging load and price risk. We propose a joint model for load and price dynamics, which is motivated by the goal of facilitating optimal hedging decisions, while also intuitively capturing the key features of the electricity market. Driven by three stochastic factors including the load process, our power price model allows for the calculation of closed-form pricing formulas for forwards and some options, products often used for hedging purposes. Making use of these results, we illustrate in a simple example the hedging benefit of these instruments, while also evaluating the performance of the model when fitted to the Texas electricity market. - Highlights: • We present a structural model for electricity spot prices in the ERCOT market. • Relationships between power price and factors such as load and gas price are studied. • Seasonal patterns and load-dependent spikes are shown to be well captured. • Closed-form results for prices of forwards, options and spread options are derived. • We demonstrate the effectiveness of hedging power demand with forwards and options

Caixa é dívida negativa sob a perspectiva de hedging no Brasil?

Directory of Open Access Journals (Sweden)

Marcio Telles Portal

2013-01-01

Full Text Available O presente estudo investigou se as companhias brasileiras de capital aberto, entre 1995 e 2008, coordenam as políticas de caixa e dívida para efeitos de hedging contra subinvestimento em condições de restrição financeira. Os resultados indicam a inexistência de um componente de hedging usando, simultaneamente, as políticas de caixa e dívida em companhias restritas. Foi observada para as companhias restritas financeiramente uma sensibilidade positiva do caixa ao fluxo de caixa e sensibilidade negativa da dívida ao fluxo de caixa, independentemente da necessidade de hedging. As companhias irrestritas não apresentaram uma sensibilidade do caixa ao fluxo de caixa significante estatisticamente, mas apresentaram sensibilidade negativa da dívida ao fluxo de caixa, resultados também independentes da necessidade de hedging. As evidências contrariam os resultados encontrados por Acharya, Almeida e Campello (2007 no mercado norte-americano, onde caixa e dívida negativa apresentaram de acordo com a necessidade de hedging diferentes papéis na otimização intertemporal dos investimentos em companhias restritas.

Immunization and Hedging of Post Retirement Income Annuity Products

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Changyu Liu

2017-03-01

Full Text Available Designing post retirement benefits requires access to appropriate investment instruments to manage the interest rate and longevity risks. Post retirement benefits are increasingly taken as a form of income benefit, either as a pension or an annuity. Pension funds and life insurers offer annuities generating long term liabilities linked to longevity. Risk management of life annuity portfolios for interest rate risks is well developed but the incorporation of longevity risk has received limited attention. We develop an immunization approach and a delta-gamma based hedging approach to manage the risks of adverse portfolio surplus using stochastic models for mortality and interest rates. We compare and assess the immunization and hedge effectiveness of fixed-income coupon bonds, annuity bonds, as well as longevity bonds, using simulations of the portfolio surplus for an annuity portfolio and a range of risk measures including value-at-risk. We show how fixed-income annuity bonds can more effectively match cash flows and provide additional hedge effectiveness over coupon bonds. Longevity bonds, including deferred longevity bonds, reduce risk significantly compared to coupon and annuity bonds, reflecting the long duration of the typical life annuity and the exposure to longevity risk. Longevity bonds are shown to be effective in immunizing surplus over short and long horizons. Delta gamma hedging is generally only effective over short horizons. The results of the paper have implications for how providers of post retirement income benefit streams can manage risks in demanding conditions where innovation in investment markets can support new products and increase the product range.

International hedging under concurrent risks of input/output prices and exchange rate : The case of Korean oil refinery

Energy Technology Data Exchange (ETDEWEB)

Yun, W C; Kim, S D [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

1997-11-01

This study develops an international hedging model which accounts for the multiple risks of input and output prices and exchange rates. Considering a fixed production technology, we formulize simultaneous minimum variance hedge ratios, which reflects inter correlations among prices. To utilize the dynamic nature of prices, time-varying conditional procedures are specified to estimate the relevant variance and covariance matrix. The time-varying representations of the variance and covariance matrix are statistically appropriate, in general. The separate hedge ratios are similar to the simultaneous hedge ratios for alternative procedures. The ex post hedging effectiveness indicate that there are substantial reduction in the variance of returns for all the procedures. The contribution of foreign currency futures is minimal due to the low correlation between commodities and exchange rates. Based on the traditional definition of hedging effectiveness, the time-varying conditional procedure provide little gain to the hedgers over a constant procedure in terms of the mean and the variance reduction. However, the performance of conditional procedures could be improved by accounting for the potential problems: mis specification problem, inappropriate definition of hedging effectiveness, and conflicts between theoretical derivation and estimation of hedge ratios. (author). 39 refs., 6 tabs.

Optimization problem and mean variance hedging on defaultable claims

OpenAIRE

Goutte, Stephane; Ngoupeyou, Armand

2012-01-01

We study the pricing and the hedging of claim {\\psi} which depends on the default times of two firms A and B. In fact, we assume that, in the market, we can not buy or sell any defaultable bond of the firm B but we can only trade defaultable bond of the firm A. Our aim is then to find the best price and hedging of {\\psi} using only bond of the firm A. Hence, we solve this problem in two cases: firstly in a Markov framework using indifference price and solving a system of Hamilton-Jacobi-Bellm...

Variance Swaps in BM&F: Pricing and Viability of Hedge

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Richard John Brostowicz Junior

2010-07-01

Full Text Available A variance swap can theoretically be priced with an infinite set of vanilla calls and puts options considering that the realized variance follows a purely diffusive process with continuous monitoring. In this article we willanalyze the possible differences in pricing considering discrete monitoring of realized variance. It will analyze the pricing of variance swaps with payoff in dollars, since there is a OTC market that works this way and thatpotentially serve as a hedge for the variance swaps traded in BM&F. Additionally, will be tested the feasibility of hedge of variance swaps when there is liquidity in just a few exercise prices, as is the case of FX optionstraded in BM&F. Thus be assembled portfolios containing variance swaps and their replicating portfolios using the available exercise prices as proposed in (DEMETERFI et al., 1999. With these portfolios, the effectiveness of the hedge was not robust in mostly of tests conducted in this work.

Modern stage and the directions of developing the accounting system for hedging corporate derivatives

OpenAIRE

Ковтун, Ірина Юріївна

2015-01-01

The peculiarities of the accounting for hedging corporate derivatives oriented to the capital maintenance through system risk management have been disclosed. The suggestions on the accounting for hedging in the modern legal environment have been made

Weather derivatives: Business hedge instrument from weather risks

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Đorđević Bojan S.

2014-01-01

Full Text Available In the late 1990s, a new financial market was developed - a market for weather derivatives, so that the risk managers could hedge their exposure to weather risk. After a rather slow start, the weather derivatives market had started to grow rapidly. Risk managers could no longer blame poor financial results on the weather. Weather risk could now be removed by hedging procedure. This paper will explain briefly what the weather derivatives are and will point out at some of the motives for use of derivatives. Thereafter we will look at the history of the weather risk market, how the weather derivatives market has developed in recent years and also who are the current and potential players in the weather derivatives market.

An analysis of the effectiveness of a joint commodity and foreign exchange rate futures hedge: The case of a Canadian crude oil trader

International Nuclear Information System (INIS)

Klusa, L.J.

1993-04-01

This study focused on reducing risk for Canadian crude oil traders exposed to crude oil price and exchange rate uncertainty. Joint static and flow period hedges were developed and compared to unhedged positions and to naive and simple hedges. Optimal hedge ratio size and hedging effectiveness were identified for a variety of hedge lifting periods and durations. The in-sample results indicated that joint hedge models were more effective than other models in terms of minimizing the variance of returns. Out-of-sample results indicated that joint and simple commodity hedges were equally effective. Other findings included: shorter duration, close to expiry hedges were the most effective; the difference between the variability of spot and future price differences and their correlations were related to hedge ratio size; and a flow period hedge was the most effective hedge when spot prices were monthly average prices. 53 refs., 3 figs., 49 tabs

FOREIGN CURRENCY RISK HEDGING

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Mihaela SUDACEVSCHI

2017-05-01

Full Text Available This paper presents the traditional types of exchange rate risk faced by firms and some of principal methods of exchange risk management that a company which make foreign currency operations can use. Foreign currency risk management involves both assessing the risk faced by the companies and adopting measures for the risk hedging or reduce the damage it may cause. The damages result from the company’s unfavorable difference between the exchange rates of the currencies in which the transactions are made.

Optimal Hedging and Pricing of Equity-Linked Life Insurance Contracts in a Discrete-Time Incomplete Market

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Norman Josephy

2011-01-01

Full Text Available We present a method of optimal hedging and pricing of equity-linked life insurance products in an incomplete discrete-time financial market. A pure endowment life insurance contract with guarantee is used as an example. The financial market incompleteness is caused by the assumption that the underlying risky asset price ratios are distributed in a compact interval, generalizing the assumptions of multinomial incomplete market models. For a range of initial hedging capitals for the embedded financial option, we numerically solve an optimal hedging problem and determine a risk-return profile of each optimal non-self-financing hedging strategy. The fair price of the insurance contract is determined according to the insurer's risk-return preferences. Illustrative numerical results of testing our algorithm on hypothetical insurance contracts are documented. A discussion and a test of a hedging strategy recalibration technique for long-term contracts are presented.

Return and volatility transmission between gold and stock sectors: Application of portfolio management and hedging effectiveness

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Dilip Kumar

2014-03-01

Full Text Available The paper investigates the first and second orders moment transmission between gold and Indian industrial sectors with an application of portfolio design and hedging effectiveness using generalised VAR-ADCC-BVGARCH model. Our findings indicate unidirectional significant return spillover from gold to stock sectors. The negative values of estimated time varying conditional correlations are mainly observed during periods of market turbulence and crisis indicating the scope of portfolio diversification and hedging during these periods. We also estimate optimal weights, hedge ratios, and hedging effectiveness for the stock-gold portfolios. Our findings suggest that stock-gold portfolio provides better diversification benefits than stock portfolios.

Bet hedging in yeast by heterogeneous, age-correlated expression of a stress protectant.

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Sasha F Levy

Full Text Available Genetically identical cells grown in the same culture display striking cell-to-cell heterogeneity in gene expression and other traits. A crucial challenge is to understand how much of this heterogeneity reflects the noise tolerance of a robust system and how much serves a biological function. In bacteria, stochastic gene expression results in cell-to-cell heterogeneity that might serve as a bet-hedging mechanism, allowing a few cells to survive through an antimicrobial treatment while others perish. Despite its clinical importance, the molecular mechanisms underlying bet hedging remain unclear. Here, we investigate the mechanisms of bet hedging in Saccharomyces cerevisiae using a new high-throughput microscopy assay that monitors variable protein expression, morphology, growth rate, and survival outcomes of tens of thousands of yeast microcolonies simultaneously. We find that clonal populations display broad distributions of growth rates and that slow growth predicts resistance to heat killing in a probabalistic manner. We identify several gene products that are likely to play a role in bet hedging and confirm that Tsl1, a trehalose-synthesis regulator, is an important component of this resistance. Tsl1 abundance correlates with growth rate and replicative age and predicts survival. Our results suggest that yeast bet hedging results from multiple epigenetic growth states determined by a combination of stochastic and deterministic factors.

An Empirical Study on Hedge Fund Portfolio Optimization, Mean-Risk Based Approaches

OpenAIRE

Li, Yang

2011-01-01

Abstract This research attempts to investigate the divergences between the Mean-Variance and the Mean-CVaR portfolio optimization methods in examining various assets classes, such as equities, bonds, and especially hedge funds. In order to get a thorough understanding of hedge funds facts and available optimization techniques, relevant literatures are carefully reviewed and incorporated into later stage computer modelling. By constructing three hypothetical portfolios, including traditiona...

A Hedge for Gödel Fuzzy Logic

Czech Academy of Sciences Publication Activity Database

Hájek, Petr; Harmancová, Dagmar

2000-01-01

Roč. 8, č. 4 (2000), s. 495-498 ISSN 0218-4885 Grant - others:COST(XE) Action 15 Institutional research plan: AV0Z1030915 Keywords : fuzzy logic * Gödel logic * intuitionistic logic * hedges Subject RIV: BA - General Mathematics Impact factor: 0.145, year: 2000

Empirical Evidence on Time-Varying Hedging Effectiveness of Emissions Allowances under Departures from the Cost-of-Carry Theory

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Kai Chang

2013-01-01

Full Text Available Under departures from the cost-of-carry theory, traded spot prices and conditional volatility disturbed from futures market have significant impacts on futures price of emissions allowances, and then we propose time-varying hedge ratios and hedging effectiveness estimation using ECM-GARCH model. Our empirical results show that conditional variance, conditional covariance, and their correlation between between spot and futures prices exhibit time-varying trends. Conditional volatility of spot prices, conditional volatility disturbed from futures market, and conditional correlation of market noises implied from spot and futures markets have significant effects on time-varying hedge ratios and hedging effectiveness. In the immature emissions allowances market, market participants optimize portfolio sizes between spot and futures assets using historical market information and then achieve higher risk reduction of assets portfolio revenues; accordingly, we can obtain better hedging effectiveness through time-varying hedge ratios with departures from the cost-of-carry theory.

Determinantes para utilização de Hedge Accouting: uma escolha contábil

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Fernando Caio Galdi

2009-01-01

Full Text Available Este estudio investiga la sistemática de la elección contable, en el medio corporativo, referente a la contratación y a la calificación, o no, de operaciones con derivativos para apli - cación de la contabilidad de hedge ( Hedge Accounting , conforme a las normas del Fasb ( SFAS 133 . Dentro de ese abordaje, fueron utilizadas variables relacionadas a los incen - tivos/beneficios que las empresas pueden tener al clasificar una transacción dentro de los requisitos necesarios para aplicación de la contabilidad de operaciones de hedge ( Hedge Accounting . Las empresas evaluadas son aquellas listadas en la NYSE en los sectores de Minería, Siderurgia/Metalurgia y Papel/Celulosa. Los datos utilizados fueron obtenidos por medio de la base de datos Economatica , websites de las firmas seleccionadas y del análisis de las demostraciones financieras publicadas en los informes anuales, en dólares norteamericanos, de cada una de las seleccionadas firmas, referentes al año 2006. Las evidencias apuntan hacia una relación positiva y significante entre la deuda de largo plazo y la aplicación de la contabilidad de hedge , lo que es consistente con la teoría y corrobora con la relación esperada.

A logical approach to fuzzy truth hedges

Czech Academy of Sciences Publication Activity Database

Esteva, F.; Godo, L.; Noguera, Carles

2013-01-01

Roč. 232, č. 1 (2013), s. 366-385 ISSN 0020-0255 Institutional support: RVO:67985556 Keywords : Mathematical fuzzy logic * Standard completeness * Truth hedges Subject RIV: BA - General Mathematics Impact factor: 3.893, year: 2013 http://library.utia.cas.cz/separaty/2016/MTR/noguera-0469148.pdf

Ambiguities of the hedge: an exercise in creative pleaching - of moments, memories and meanings

DEFF Research Database (Denmark)

Harvey, David

2017-01-01

of subjection’, connected invariably with Parliamentary enclosure and proletarianisation, the English hedgerow is also an iconic symbol of rural tranquillity, and mainstay of many conservation and biodiversity agendas, with hedge-laying — – the practice of constructing a living hedge — championed as a key item...

How hedge woody species diversity and habitat change is a function of land use history and recent management in a European agricultural landscape.

Science.gov (United States)

McCann, Thomas; Cooper, Alan; Rogers, David; McKenzie, Paul; McErlean, Thomas

2017-07-01

European hedged agricultural landscapes provide a range of ecosystem services and are an important component of cultural and biodiversity heritage. This paper investigates the extent of hedges, their woody species diversity (including the influence of historical versus recent hedge origin) and dynamics of change. The rationale is to contribute to an ecological basis for hedge habitat management. Sample sites were allocated based on a multivariate classification of landscape attributes. All field boundaries present in each site were mapped and surveyed in 1998 and 2007. To assess diversity, a list of all woody species was recorded in one standard 30 m linear plot within each hedge. There was a net decrease in hedge habitat extent, mainly as a result of removal, and changes between hedges and other field boundary types due to the development and loss of shrub growth-form. Agricultural intensification, increased rural building, and variation in hedge management practices were the main drivers of change. Hedges surveyed at baseline, which were lost at resurvey, were more species rich than new hedges gained. Hedges coinciding with historical land unit boundaries of likely Early Medieval origin were found to be more species rich. The most frequent woody species in hedges were native, including a high proportion with Fraxinus excelsior, a species under threat from current and emerging plant pests and pathogens. Introduced species were present in circa 30% of hedges. We conclude that since hedge habitat distribution and woody species diversity is a function of ecology and anthropogenic factors, the management of hedges in enclosed agricultural landscapes requires an integrated approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of hedging strategies in interval models

NARCIS (Netherlands)

Roorda, Berend; Engwerda, Jacob; Schumacher, J.M.

2005-01-01

For a proper assessment of risks associated with the trading of derivatives, the performance of hedging strategies should be evaluated not only in the context of the idealized model that has served as the basis of strategy development, but also in the context of other models. In this paper we

Determinantes para utilização de Hedge Accouting: uma escolha contábil

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Fernando Caio Galdi

2009-08-01

Full Text Available Este estudo investiga a sistemática da escolha contábil, no meio corporativo,referente à contratação e à qualificação, ou não, de operações com derivativos para aplicação da contabilidade de hedge (Hedge Accounting, conforme as normas do Fasb (SFAS 133. Dentro dessa abordagem, foram utilizadas variáveis relacionadas aos incentivos/benefícios que as empresas podem ter ao classificarem uma transação dentro dos requisitos necessários para aplicação da contabilidade de operações de hedge (Hedge Accounting. As empresas avaliadas são aquelas listadas na NYSE nos setores de Mineração, Siderurgia/Metalurgia e Papel/Celulose. Os dados utilizados foram obtidos por meio da base de dados Economatica, websites das firmas selecionadas e da análise das demonstrações financeiras publicadas nos relatórios anuais, em dólares norte-americanos, de cada uma das selecionadas firmas, referentes ao ano de 2006. As evidências apontam para uma relação positiva e significante entre a dívida de longo prazo e a aplicação da contabilidade de hedge, o que é consistente com a teoria e corrobora com a relação esperada.

The role of cointegration for optimal hedging with heteroscedastic error term

DEFF Research Database (Denmark)

Gatarek, Lukasz; Johansen, Søren

2017-01-01

a cointegrating vector for large h, thereby giving a bounded risk. Taking the expected return into account, the portfolio that maximizes the Sharpe ratio is found, and it is shown that it also approaches a cointegration portfolio. For constant conditional volatility, the conditional variance can be estimated...... forward contracts for electricity, which are hedged by forward contracts for fuel prices. The main conclusion of the paper is that for optimal hedging, one should exploit the cointegrating properties for long horizons, but for short horizons more weight should be put on the remaining dynamics....

The role of cointegration for optimal hedging with heteroscedastic error term

DEFF Research Database (Denmark)

Gatarek, Lutasz; Johansen, Søren

a cointegrating vector for large h, thereby giving a bounded risk. Taking the expected return into account, the portfolio that maximizes the Sharpe ratio is found, and it is shown that it also approaches a cointegration portfolio. For constant conditional volatility, the conditional variance can be estimated...... forward contracts for electricity, which are hedged by forward contracts for fuel prices. The main conclusion of the paper is that for optimal hedging, one should exploit the cointegrating properties for long horizons, but for short horizons more weight should be put on the remaining dynamics....

Contribution to modeling and dynamic risk hedging in energy markets

International Nuclear Information System (INIS)

Noufel, Frikha

2010-12-01

This thesis is concerned with probabilistic numerical problems about modeling, risk control and risk hedging motivated by applications to energy markets. The main tool is based on stochastic approximation and simulation methods. This thesis consists of three parts. The first one is devoted to the computation of two risk measures of the portfolio loss distribution L: the Value-at-Risk (VaR) and the Conditional Value-at-Risk (CVaR). This computation uses a stochastic algorithm combined with an adaptive variance reduction technique. The first part of this chapter deals with the finite dimensional case, the second part extends the results of the first part to the case of a path-dependency process and the last one deals low discrepancy sequences. The second chapter is devoted with risk minimizing hedging strategies in an incomplete market operating in discrete time using quantization based stochastic approximation. Theoretical results on CVaR hedging are presented then numerical aspects are addressed in a Markovian framework. The last part deals with joint modeling of Gas and Electricity spot prices. The multi-factor model presented is based on stationary Ornstein process with parameterized diffusion coefficient. (author)

Price volatility, hedging and variable risk premium in the crude oil market

International Nuclear Information System (INIS)

Ahmad Jalali-Naini; Maryam Kazemi Manesh

2006-01-01

The crude oil price exhibits a high degree of volatility which varies significantly over time. Such characteristics imply that the oil market is a promising area for testing volatility models. Testing and predicting volatility using ARCH and GARCH models have grown in the literature. A useful application of the volatility models is in the formulation of hedging strategies. In this paper we compare the optimal hedge ratio for the crude oil using the classical minimum risk approach and use ARCH to incorporate the effect of heteroskedasticity in the residuals on the hedge ratio. In addition, we test for the existence of a variable risk premium in the crude oil market. We find that, assuming rational expectations, there is a non-zero risk premium. We test for the variability of the risk premia and find evidence in its support when we employed a multivariate GARCH model. (author)

The Impact of Hedge Fund Activism on Target Firm Performance, Executive Compensation and Executive Wealth

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Andrew Carrothers

2017-10-01

Full Text Available This paper examines the relationship between hedge fund activism and target firm performance, executive compensation, and executive wealth. It introduces a theoretical framework that describes the activism process as a sequence of discrete decisions. The methodology uses regression analysis on a matched sample based on firm size, industry, and market-to-book ratio. All regressions control for industry and year fixed effects. Schedule 13D Securities and Exchange Commission (SEC filings are the source for the statistical sample of hedge fund target firms. I supplement that data with target firm financial, operating, and share price information from the CRSP-COMPUSTAT merged database. Activist hedge funds target undervalued or underperforming firms with high profitability and cash flows. They do not avoid firms with powerful CEOs. Leverage, executive compensation, pay for performance and CEO turnover increase at target firms after the arrival of the activist hedge fund. Target firm executives’ wealth is more sensitive to changes in share price after hedge fund activism events suggesting that the executive team experiences changes to their compensation structure that provides incentive to take action to improve returns to shareholders. The top executives reap rewards for increasing firm value but not for increased risk taking.

Forward, Forward Option and No Hedging Which One is the Best for Managing Currency Risk?

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Riko Hendrawan

2017-07-01

Full Text Available Bank Indonesia Regulation No.18/18/PBI/2016 concerning foreign exchange transactions against rupiah between banks and domestic parties, indicates that the importance of hedging for business actors in Indonesia. Based on the data of the rupiah exchange rate movement against the dollar from January 2006 to December 2016 shows that the fluctuation of the rupiah against the US dollar tends to weaken, although at some point the observation shows the strengthening of the rupiah against the US dollar. The purpose of this research is to assess impact of Forward, Forward Option and No Hedging Strategy for managing currency exposure between IDR to USD. Using data from January 2006–December 2016 taken from website of Bank Indonesia and Federal Reserve. Total 396 simulations,consists of 132 using Forward simulations, 132 using Forward Option simulations and 132 using No Hedging simulations. Findings from this research show that Forward Option was has no positive contribution in managing currency exposure, No Hedging Strategy has 36,36 percent positive contribution and forward contract has 72,73 percent positive contribution in managing currency exposure. Its means Forward Contract was better than Forward Option and No Hedging Strategies in managing currency exposure.

Pricing and hedging derivative securities with neural networks: Bayesian regularization, early stopping, and bagging.

Science.gov (United States)

Gençay, R; Qi, M

2001-01-01

We study the effectiveness of cross validation, Bayesian regularization, early stopping, and bagging to mitigate overfitting and improving generalization for pricing and hedging derivative securities with daily S&P 500 index daily call options from January 1988 to December 1993. Our results indicate that Bayesian regularization can generate significantly smaller pricing and delta-hedging errors than the baseline neural-network (NN) model and the Black-Scholes model for some years. While early stopping does not affect the pricing errors, it significantly reduces the hedging error (HE) in four of the six years we investigated. Although computationally most demanding, bagging seems to provide the most accurate pricing and delta hedging. Furthermore, the standard deviation of the MSPE of bagging is far less than that of the baseline model in all six years, and the standard deviation of the average HE of bagging is far less than that of the baseline model in five out of six years. We conclude that they be used at least in cases when no appropriate hints are available.

Operações de Hedge no Agronegócio - Uma Análise Baseada no Hedging Accounting'

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Maria Jose de Camargo Machado De Zen

2009-10-01

Full Text Available O mercado de derivativos vem ganhando importância no contexto econômico mundial, demandando procedimentos contábeis que evidenciem corretamente os riscos e os benefícios envolvidos em tais operações. Desta maneira, este artigo mostra e discute aspectos da contabilização de operações de hedge, utilizando como base para análise, dois instrumentos utilizados com a finalidade de hedge no agronegócio brasileiro: a Cédula de Produto Rural (CPR e os contratos futuros agropecuários. Através de pesquisa bibliográfica, foram estudados os procedimentos do Hedging Accounting, segundo a normatização do FASB, e da CVM. Através do desenvolvimento de um exemplo teórico foram analisados e discutidos estes procedimentos, comparando as divergências de critérios entre as normas dos dois órgãos citados, e o impacto destes na análise das demonstrações financeiras tanto do produtor rural como da agroindústria. Esta análise demonstra que há divergências significativas na evidenciação destes instrumentos, principalmente dos contratos futuros, entre as normas analisadas. Ja para a CPR, foi proposta uma contabilização segundo o conceito de "derivativo embutido", conceito este contemplado pelo próprio FASB para alguns contratos com características híbridas. Existe uma necessidade de adequação das normas da CVM ao FASB, visto a importância de evidenciar estas operações no "corpo"do balanço, tanto no aspecto de exposição ao risco, como para a comparando de estratégias diferentes de proteção. No entanto, analisando somente dois títulos, fica evidente a dificuldade da adequação das normas brasileiras ao FASB.

Optimization of multi-reservoir operation with a new hedging rule: application of fuzzy set theory and NSGA-II

Science.gov (United States)

Ahmadianfar, Iman; Adib, Arash; Taghian, Mehrdad

2017-10-01

The reservoir hedging rule curves are used to avoid severe water shortage during drought periods. In this method reservoir storage is divided into several zones, wherein the rationing factors are changed immediately when water storage level moves from one zone to another. In the present study, a hedging rule with fuzzy rationing factors was applied for creating a transition zone in up and down each rule curve, and then the rationing factor will be changed in this zone gradually. For this propose, a monthly simulation model was developed and linked to the non-dominated sorting genetic algorithm for calculation of the modified shortage index of two objective functions involving water supply of minimum flow and agriculture demands in a long-term simulation period. Zohre multi-reservoir system in south Iran has been considered as a case study. The results of the proposed hedging rule have improved the long-term system performance from 10 till 27 percent in comparison with the simple hedging rule, where these results demonstrate that the fuzzification of hedging factors increase the applicability and the efficiency of the new hedging rule in comparison to the conventional rule curve for mitigating the water shortage problem.

Missing Data Bias on a Selective Hedging Strategy

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Kiss Gábor Dávid

2017-03-01

Full Text Available Foreign exchange rates affect corporate profitability both on the macro and cash-flow level. The current study analyses the bias of missing data on a selective hedging strategy, where currency options are applied in case of Value at Risk (1% signs. However, there can be special occasions when one or some data is missing due to lack of a trading activity. This paper focuses on the impact of different missing data handling methods on GARCH and Value at Risk model parameters, because of selective hedging and option pricing based on them. The main added value of the current paper is the comparison of the impact of different methods, such as listwise deletion, mean substitution, and maximum likelihood based Expectation Maximization, on risk management because this subject has insufficient literature. The current study tested daily closing data of floating currencies from Kenya (KES, Ghana (GHS, South Africa (ZAR, Tanzania (TZS, Uganda (UGX, Gambia (GMD, Madagascar (MGA and Mozambique (MZN in USD denomination against EUR/USD rate between March 8, 2000 and March 6, 2015 acquired from the Bloomberg database. Our results suggested the biases of missingness on Value at Risk and volatility models, presenting significant differences among the number of extreme fluctuations or model parameters. A selective hedging strategy can have different expenditures due to the choice of method. This paper suggests the usage of mean substitution or listwise deletion for daily financial time series due to their tendency to have a close to zero first momentum

(IAM Series No 004) Highwaymen or Heroes: Should Hedge Funds be Regulated?

OpenAIRE

Jean-Pierre Zigrand; Ashley Taylor; Jon Danielsson

2004-01-01

The exponential growth of hedge funds, their role in financial crises in the 1990s, and examples of fraudulent behaviour have precipitated a heated debate over their regulatory status. The existing approaches of greater disclosure and activity restrictions appear too blunt to be effective and may stifle the benefits hedge funds can bring to the financial system. But, even the remote possibility of a systemic crisis weighs against no regulation. If reform is delayed until after a crisis it is ...

The European Union, Financial Crises and the Regulation of Hedge Funds: A Policy Cul-de-Sac or Policy Window?

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David John Lutton

2008-11-01

Full Text Available A series of financial crises involving hedge funds has created a general perception that action needs to be taken. A number of key member states and political actors favour tighter regulation. Traditional bureaucratic theory suggests that the European Commission would seek to maximise this ‘policy window’, and yet there remains no single unified European Union (EU regulatory framework specifically targeting hedge funds. The nature of the regulatory regime, which has generally demanded a ‘light touch’ approach, means there are strict limits the EU’s ability to act. From an EU perspective, hedge fund regulation appears to be a policy cul-de-sac. However, the relationship between hedge funds and financial crisis is complex and less straightforward than is often portrayed. Hedge fund regulation cannot, however, be considered in isolation but should be viewed in the context of a wider programme to integrate European financial services markets. Viewed from this perspective, EU regulation is in fact changing the landscape of the hedge fund industry through a process of negative integration.

The performance of multi-factor term structure models for pricing and hedging caps and swaptions

NARCIS (Netherlands)

Driessen, J.J.A.G.; Klaassen, P.; Melenberg, B.

2000-01-01

In this paper we empirically compare a wide range of different term structure models when it comes to the pricing and, in particular, hedging of caps and swaptions. We analyze the influence of the number of factors on the hedging and pricing results, and investigate which type of data "interest rate

The Performance of Multi-Factor Term Structure Models for Pricing and Hedging Caps and Swaptions

NARCIS (Netherlands)

Driessen, J.J.A.G.; Klaassen, P.; Melenberg, B.

2000-01-01

In this paper we empirically compare different term structure models when it comes to the pricing and hedging of caps and swaptions.We analyze the influence of the number of factors on the pricing and hedging results, and investigate which type of data -interest rate data or derivative price data-

Striking Features of the New Market Companies Adopting Hedge Accounting

Directory of Open Access Journals (Sweden)

Leandro Augusto Toigo

2015-08-01

Full Text Available This research had as main objective to analyze the corporate and financial governance characteristics that discriminate against groups of companies that adopt hedge accounting in the new market for risk management. In this sense, there was descriptive survey the site of BM&FBOVESPA, conducted through desk review of the financial statements of 31/12/2012, including the explicative notes and management reports, there was also collecting data in reference form and Economatica. The population corresponds as 128 companies of the governance level - new market, and that the reserve sample was random and probabilistic, comprising 88 companies. We used a construct of the CPC 40 that deals with hedge accounting in order to segment the sample companies opting or not hedge accounting. The results of the application of Pearson's correlation and logistic regression with the Hosmer and Lemoshow tests (HLT and Test Omnibus coefficient model (OTMC, have shown that companies with ownership concentration, foreign investors and larger assets are adopting more significantly CPC 40. It follows that Brazilian companies belonging to the new market that adopt the practice of accounting disclosure to demonstrate improvement in risk management of the investments of the shareholders, are large companies with the capital structure composed of foreign investor and representative shareholder wealth.

Pricing and hedging in the VIX derivative market

NARCIS (Netherlands)

Kozarski, R.

2013-01-01

In course of the analysis, we take advantage of extended market evidence in the model estimation and a more complex design to assess the model pricing and hedging performance. The pursuit of more empirically relevant frameworks pays-off is a more precise pricing. However, instead of developing

Score-Driven Nelson Siegel: Hedging Long-Term Liabilities

NARCIS (Netherlands)

R. Quaedvlieg (Rogier); P.C. Schotman (Peter)

2016-01-01

textabstractDue to its affine structure the Nelson-Siegel model for yield curves can be transformed to a factor model for excess bond returns. Hedging interest rate risk in this framework amounts to eliminating the factor exposure and minimizing the residual risk. Fitting the model directly on

Belief elicitation in experiments: is there a hedging problem?

Czech Academy of Sciences Publication Activity Database

Blanco, M.; Engelmann, Dirk; Koch, A. K.; Normann, H.-T.

2010-01-01

Roč. 13, č. 4 (2010), s. 412-438 ISSN 1386-4157 Institutional research plan: CEZ:AV0Z70850503 Keywords : belief elicitation * hedging * experimental methodology Subject RIV: AH - Economics Impact factor: 1.868, year: 2010

resistance of napier grass clones to napier grass stunt disease

African Journals Online (AJOL)

ACSS

Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease. (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

Resistance of Napier grass clones to Napier grass Stunt Disease ...

African Journals Online (AJOL)

Napier grass (Pennisetum purpureum Schumach) is the major livestock fodder under intensive and semi-intensive systems in East Africa. However, the productivity of the grass is constrained by Napier grass Stunt Disease (NSD). The purpose of this study was to identify Napier grass clones with resistance to NSD.

Bet hedging via seed banking in desert evening primroses (Oenothera, Onagraceae): demographic evidence from natural populations.

Science.gov (United States)

Evans, Margaret E K; Ferrière, Régis; Kane, Michael J; Venable, D Lawrence

2007-02-01

Bet hedging is one solution to the problem of an unpredictably variable environment: fitness in the average environment is sacrificed in favor of lower variation in fitness if this leads to higher long-run stochastic mean fitness. While bet hedging is an important concept in evolutionary ecology, empirical evidence that it occurs is scant. Here we evaluate whether bet hedging occurs via seed banking in natural populations of two species of desert evening primroses (Oenothera, Onagraceae), one annual and one perennial. Four years of data on plants and 3 years of data on seeds yielded two transitions for the entire life cycle. One year was exceptionally dry, leading to reproductive failure in the sample areas, and the other was above average in precipitation, leading to reproductive success in four of five populations. Stochastic simulations of population growth revealed patterns indicative of bet hedging via seed banking, particularly in the annual populations: variance in fitness and fitness in the average environment were lower with seed banking than without, whereas long-run stochastic mean fitness was higher with seed banking than without across a wide range of probabilities of the wet year. This represents a novel, unusually rigorous demonstration of bet hedging from field data.

Testing Commodities as Safe Haven and Hedging Instrument on ASEAN's Five Stock Markets

OpenAIRE

Robiyanto, Robiyanto

2017-01-01

This study attempts to analyze commodity market instruments such as gold, silver, platinum, palladium, and West Texas Intermediate (WTI) crude oil’s potential as hedge and safe haven toward some stock markets in South East Asia such as in Indonesia, Singapore, Malaysia, Philippines, and Thailand. To analyze the data, GARCH (1,1) was applied. The research findings showed that gold, silver, platinum, palladium, and WTI could not play their role as hedging instrument for five South East Asi...

The Interaction between Real Options and Financial Hedging: An Empirical Study of Danish Non-Financial Companies

DEFF Research Database (Denmark)

Aabo, Tom

The interaction between real options and financial hedging is analyzed empirically. A majority of Danish non-financial companies either (1) chooses at times not to hedge an exchange rate operating exposure financially due to the possibility of the company to react to changes in exchange rates...

A mixed C-vine copula model for hedging price and volumetric risk in wind power trading

DEFF Research Database (Denmark)

Pircalabu, Anca; Jung, Jesper

2017-01-01

correlation with the much more liquid German market to construct a proxy hedge. We propose a three-dimensional mixed vine copula to model the evolution of the Danish and German spot electricity prices and the Danish wind power production. We construct a realistic hedging portfolio by identifying various...... of not only forwards, but also a basket of e.g. call and put options. Illiquidity and an almost non-existent market for options challenge however the optimal hedging of joint price and volumetric risk in many market places. Here, we consider the case of the Danish power market, and exploit its strong positive...... instruments available in the market, such as real options in the form of the right to transfer electricity across the border and the right to convert electricity to heat. Using the proposed vine copula to determine optimal hedging decisions, we show that significant benefits are to be drawn by extending...

12 CFR 956.6 - Use of hedging instruments.

Science.gov (United States)

2010-01-01

... counterparty for over-the-counter derivative contracts shall include: (i) A requirement that market value... reasonable estimate of the market value of the over-the-counter derivative contract at termination (standard.... Derivative instruments that do not qualify as hedging instruments pursuant to GAAP may be used only if a non...

Incentive Contracts and Hedge Fund Management

OpenAIRE

Jens Carsten Jackwerth; James E. Hodder

2005-01-01

This paper investigates dynamically optimal risk-taking by an expected-utility maximizing manager of a hedge fund. We examine the effects of variations on a compensation structure that includes a percentage management fee, a performance incentive for exceeding a specified highwater mark, and managerial ownership of fund shares. In our basic model, there is an exogenous liquidation barrier where the fund is shut down due to poor performance. We also consider extensions where the manager can vo...

Hedging Cash Flows from Commodity Processing

OpenAIRE

Dahlgran, Roger A.

2005-01-01

Agribusinesses make long-term plant-investment decisions based on discounted cash flow. It is therefore incongruous for an agribusiness firm to use cash flow as a plant-investment criterion and then to completely discard cash flow in favor of batch profits as an operating objective. This paper assumes that cash flow and its stability is important to commodity processors and examines methods for hedging cash flows under continuous processing. Its objectives are (a) to determine how standard he...

Value at Risk and Hedge Fund Return - Does High Risk Bring High Return?

OpenAIRE

Jing, Tao; Zhao, Hongxiang

2010-01-01

This paper mainly focuses on the correlation between live hedge fund return and their value at risk (VaR), and is based on the historical data from May 2000 to April 2010. The authors adopt portfolio level analyses and fund level cross-sectional regression, and find that there is significant positive correlation, both statistically and economically, between the hedge fund return and VaRs (parametric, non-parametric and GARCH). Further research is conducted by sub-dividing the overall period i...

Hedging strategies in energy markets: the case of electricity retailers

International Nuclear Information System (INIS)

Boroumand, Raphael Homayoun; Goutte, Stephane; Porcher, Simon; Porcher, Thomas

2015-01-01

As market intermediaries, electricity retailers buy electricity from the wholesale market or self-generate for re(sale) on the retail market. Electricity retailers are uncertain about how much electricity their residential customers will use at any time of the day until they actually turn switches on. While demand uncertainty is a common feature of all commodity markets, retailers generally rely on storage to manage demand uncertainty. On electricity markets, retailers are exposed to joint quantity and price risk on an hourly basis given the physical singularity of electricity as a commodity. In the literature on electricity markets, few articles deals on intra-day hedging portfolios to manage joint price and quantity risk whereas electricity markets are hourly markets. The contributions of the article are twofold. First, we define through a VaR and CVaR model optimal portfolios for specific hours (3 a.m., 6 a.m.,...,12 p.m.) based on electricity market data from 2001 to 2011 for the French market. We prove that the optimal hedging strategy differs depending on the cluster hour. Secondly, we demonstrate the significantly superior efficiency of intra-day hedging portfolios over daily (therefore weekly and yearly) portfolios. Over a decade (2001-2011), our results clearly show that the losses of an optimal daily portfolio are at least nine times higher than the losses of optimal intra-day portfolios. (authors)

Variance-optimal hedging for processes with stationary independent increments

DEFF Research Database (Denmark)

Hubalek, Friedrich; Kallsen, J.; Krawczyk, L.

We determine the variance-optimal hedge when the logarithm of the underlying price follows a process with stationary independent increments in discrete or continuous time. Although the general solution to this problem is known as backward recursion or backward stochastic differential equation, we...

Currency Hedging for International Stock Portfolios : A General Approach

NARCIS (Netherlands)

de Roon, F.A.; Nijman, T.E.; Werker, B.J.M.

1999-01-01

This paper tests whether hedging currency risk improves the performance of international stock portfolios. We use a generalized performance measure which allows for investor-dependencies such as different utility functions and the presence of nontraded risks. In addition we show that an auxiliary

Dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit

International Nuclear Information System (INIS)

Thameem Ansari, M.Md.; Velusami, S.

2010-01-01

A design of dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit is proposed in this paper. The design methodology of dual mode linguistic hedge fuzzy logic controller is a hybrid model based on the concepts of linguistic hedges and hybrid genetic algorithm-simulated annealing algorithms. The linguistic hedge operators are used to adjust the shape of the system membership functions dynamically and can speed up the control result to fit the system demand. The hybrid genetic algorithm-simulated annealing algorithm is adopted to search the optimal linguistic hedge combination in the linguistic hedge module. Dual mode concept is also incorporated in the proposed controller because it can improve the system performance. The system with the proposed controller was simulated and the frequency deviation resulting from a step load disturbance is presented. The comparison of the proportional plus integral controller, fuzzy logic controller and the proposed dual mode linguistic hedge fuzzy logic controller shows that, with the application of the proposed controller, the system performance is improved significantly. The proposed controller is also found to be less sensitive to the changes in the parameters of the system and also robust under different operating modes of the hybrid power system.

Pricing and Hedging Guaranteed Returns on Mix Funds

NARCIS (Netherlands)

Vellekoop, M.H.; van de Kamp, A.A.; Post, B.A.

2006-01-01

Abstract In this paper we propose a valuation and hedging strategy for a guaranteed minimal rate of return on a mix fund, which participates in both bonds and stocks. For the case where a fixed amount of money is invested, we show that a European put option on the mix fund replicates the cash flows

77 FR 63360 - Permal Hedge Strategies Fund, et al.;

Science.gov (United States)

2012-10-16

... SECURITIES AND EXCHANGE COMMISSION [Investment Company Act Release No. IC-30228; 812-14011] Permal Hedge Strategies Fund, et al.; Notice of Application October 9, 2012. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of an application under section 6(c) of the Investment Company...

Environmental Assessment Addressing the Emerald Breeze Resort, Santa Rosa Island, Fort Walton Beach, Florida

Science.gov (United States)

2009-09-11

Road construction and maintenance activities have introduced and spread cogon grass (Imperata cylindrical) and torpedo grass (Panicum repens) to...Chinese tallow, or popcorn tree (Triadica sebifera), cogon grass , Japanese climbing fern (Lygodium japonicum), Chinese privet/hedge (Ligustrum sinense...stormwater wetlands, wildlife habitat swales, grassed filter strips)  Runoff pretreatment practices (e.g., catch basins, in-line storage, manufactured

A seasonal copula mixture for hedging the clean spark spread with wind power futures

DEFF Research Database (Denmark)

Christensen, Troels Sønderby; Pircalabu, Anca; Høg, Esben

2018-01-01

The recently introduced German wind power futures have brought the opportunity to address the problem of volume risk in wind power generation directly. In this paper we study the hedging benefits of these instruments in the context of gas-fired power plants by employing a strategy that allows...... and the dependence structure, while being straightforward and easy to implement. Based on Monte Carlo simulations from the proposed model, the results indicate that significant benefits can be achieved by using wind power futures to hedge the spot clean spark spread. Moreover, a comparison study shows...... trading in the spot clean spark spread and wind power futures. To facilitate hedging decisions, we propose a time-varying copula mixture for the joint behavior of the spot clean spark spread and the daily wind index. The model describes the data surprisingly well, both in terms of the marginals...

Environmental hedging: A theory and method for reconciling reservoir operations for downstream ecology and water supply

Science.gov (United States)

Adams, L. E.; Lund, J. R.; Moyle, P. B.; Quiñones, R. M.; Herman, J. D.; O'Rear, T. A.

2017-09-01

Building reservoir release schedules to manage engineered river systems can involve costly trade-offs between storing and releasing water. As a result, the design of release schedules requires metrics that quantify the benefit and damages created by releases to the downstream ecosystem. Such metrics should support making operational decisions under uncertain hydrologic conditions, including drought and flood seasons. This study addresses this need and develops a reservoir operation rule structure and method to maximize downstream environmental benefit while meeting human water demands. The result is a general approach for hedging downstream environmental objectives. A multistage stochastic mixed-integer nonlinear program with Markov Chains, identifies optimal "environmental hedging," releases to maximize environmental benefits subject to probabilistic seasonal hydrologic conditions, current, past, and future environmental demand, human water supply needs, infrastructure limitations, population dynamics, drought storage protection, and the river's carrying capacity. Environmental hedging "hedges bets" for drought by reducing releases for fish, sometimes intentionally killing some fish early to reduce the likelihood of large fish kills and storage crises later. This approach is applied to Folsom reservoir in California to support survival of fall-run Chinook salmon in the lower American River for a range of carryover and initial storage cases. Benefit is measured in terms of fish survival; maintaining self-sustaining native fish populations is a significant indicator of ecosystem function. Environmental hedging meets human demand and outperforms other operating rules, including the current Folsom operating strategy, based on metrics of fish extirpation and water supply reliability.

Semi-nonparametric VaR forecasts for hedge funds during the recent crisis

Science.gov (United States)

Del Brio, Esther B.; Mora-Valencia, Andrés; Perote, Javier

2014-05-01

The need to provide accurate value-at-risk (VaR) forecasting measures has triggered an important literature in econophysics. Although these accurate VaR models and methodologies are particularly demanded for hedge fund managers, there exist few articles specifically devoted to implement new techniques in hedge fund returns VaR forecasting. This article advances in these issues by comparing the performance of risk measures based on parametric distributions (the normal, Student’s t and skewed-t), semi-nonparametric (SNP) methodologies based on Gram-Charlier (GC) series and the extreme value theory (EVT) approach. Our results show that normal-, Student’s t- and Skewed t- based methodologies fail to forecast hedge fund VaR, whilst SNP and EVT approaches accurately success on it. We extend these results to the multivariate framework by providing an explicit formula for the GC copula and its density that encompasses the Gaussian copula and accounts for non-linear dependences. We show that the VaR obtained by the meta GC accurately captures portfolio risk and outperforms regulatory VaR estimates obtained through the meta Gaussian and Student’s t distributions.

The Application of backward stochastic differential equation with stopping time in hedging American contingent claims

International Nuclear Information System (INIS)

Wang Bo; Song Ruili

2009-01-01

We consider a more general wealth process with a drift coefficient which is Lipschitz continuous and the portfolio process with convex constraint. We convert the problem of hedging American contingent claims into the problem of minimal solution of backward stochastic differential equation with stopping time. We adopt the penalization method for constructing the minimal solution of stochastic differential equations and obtain the upper hedging price of American contingent claims.

The Regional Special Operations Headquarters: Franchising the NATO Model as a Hedge in Lean Times

Science.gov (United States)

2012-04-01

1 AIR FORCE FELLOWS AIR UNIVERSITY THE REGIONAL SPECIAL OPERATIONS HEADQUARTERS: FRANCHISING THE NATO MODEL AS A HEDGE IN LEAN...Headquarters: Franchising The NATO Model As A Hedge In Lean Times 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...it is not copyrighted, but is the property of the United States government. 3 The Regional Special Operations Headquarters: Franchising the

Hedging and Boosting in English and Indonesian Research Articles

Science.gov (United States)

Sanjaya, I Nyoman Suka

2013-01-01

The present cross-cultural and cross-disciplinary study was aimed at exploring the similarities and differences between English and Indonesian research articles from the disciplines of applied linguistics and chemistry in terms of frequency of usage of hedges (e.g. "perhaps," "may") and boosters (e.g. "clearly,"…

Hedges Used in Business Emails: A Corpus Study on the Language Strategy of International Business Communication Online

Science.gov (United States)

Yue, Siwei; Wang, Xuefei

2014-01-01

Based on a corpus of 296 authentic business emails produced in computer-mediated business communication from 7 Chinese international trade enterprises, this paper addresses the language strategy applied in CMC (Computer-mediated Communication) by examining the use of hedges. With the emergence of internet, a wider range of hedges are applied…

Hedging endowment assurance products under interest rate and mortality risk

NARCIS (Netherlands)

Chen, A.; Mahayni, A.

2007-01-01

This paper analyzes how model misspecification associated with both interest rate and mortality risk influences hedging decisions of insurance companies. For this purpose, diverse risk management strategies which are riskminimizing when model risk is ignored come into consideration. The

Mean-Variance Hedging on Uncertain Time Horizon in a Market with a Jump

International Nuclear Information System (INIS)

Kharroubi, Idris; Lim, Thomas; Ngoupeyou, Armand

2013-01-01

In this work, we study the problem of mean-variance hedging with a random horizon T∧τ, where T is a deterministic constant and τ is a jump time of the underlying asset price process. We first formulate this problem as a stochastic control problem and relate it to a system of BSDEs with a jump. We then provide a verification theorem which gives the optimal strategy for the mean-variance hedging using the solution of the previous system of BSDEs. Finally, we prove that this system of BSDEs admits a solution via a decomposition approach coming from filtration enlargement theory

Mean-Variance Hedging on Uncertain Time Horizon in a Market with a Jump

Energy Technology Data Exchange (ETDEWEB)

Kharroubi, Idris, E-mail: kharroubi@ceremade.dauphine.fr [Université Paris Dauphine, CEREMADE, CNRS UMR 7534 (France); Lim, Thomas, E-mail: lim@ensiie.fr [Université d’Evry and ENSIIE, Laboratoire d’Analyse et Probabilités (France); Ngoupeyou, Armand, E-mail: armand.ngoupeyou@univ-paris-diderot.fr [Université Paris 7, Laboratoire de Probabilités et Modèles Aléatoires (France)

2013-12-15

In this work, we study the problem of mean-variance hedging with a random horizon T∧τ, where T is a deterministic constant and τ is a jump time of the underlying asset price process. We first formulate this problem as a stochastic control problem and relate it to a system of BSDEs with a jump. We then provide a verification theorem which gives the optimal strategy for the mean-variance hedging using the solution of the previous system of BSDEs. Finally, we prove that this system of BSDEs admits a solution via a decomposition approach coming from filtration enlargement theory.

Determinantes para utilização de Hedge Accouting: uma escolha contábil

OpenAIRE

Fernando Caio Galdi; Luiz Fernando Grama Guerra

2009-01-01

Este estudio investiga la sistemática de la elección contable, en el medio corporativo, referente a la contratación y a la calificación, o no, de operaciones con derivativos para apli - cación de la contabilidad de hedge ( Hedge Accounting ), conforme a las normas del Fasb ( SFAS 133 ). Dentro de ese abordaje, fueron utilizadas variables relacionadas a los incen - tivos/beneficios que las empresas pueden tener al clasificar una transacción dentro de los requisitos necesarios para aplicac...

Gene Expression Profiling of Grass Carp (Ctenopharyngodon idellus and Crisp Grass Carp

Directory of Open Access Journals (Sweden)

Ermeng Yu

2014-01-01

Full Text Available Grass carp (Ctenopharyngodon idellus is one of the most important freshwater fish that is native to China, and crisp grass carp is a kind of high value-added fishes which have higher muscle firmness. To investigate biological functions and possible signal transduction pathways that address muscle firmness increase of crisp grass carp, microarray analysis of 14,900 transcripts was performed. Compared with grass carp, 127 genes were upregulated and 114 genes were downregulated in crisp grass carp. Gene ontology (GO analysis revealed 30 GOs of differentially expressed genes in crisp grass carp. And strong correlation with muscle firmness increase of crisp grass carp was found for these genes from differentiation of muscle fibers and deposition of ECM, and also glycolysis/gluconeogenesis pathway and calcium metabolism may contribute to muscle firmness increase. In addition, a number of genes with unknown functions may be related to muscle firmness, and these genes are still further explored. Overall, these results had been demonstrated to play important roles in clarifying the molecular mechanism of muscle firmness increase in crisp grass carp.

The effects of liquidity and share restrictions on hedge fund performance in bull and bear markets

OpenAIRE

El-Alawa, Y. (Yasmin)

2016-01-01

Abstract Hedge funds are increasingly becoming a popular alternative investment vehicle. They are much more flexible and can freely choose from a pool of investment strategies due to their limited regulations. This gives them the flexibility to exploit opportunities in order to generate high returns at low risk. In order to have access to the freedom and flexibility to engage in different investment strategies, hedge funds ...

Are fund of hedge fund returns asymmetric?

OpenAIRE

Lynch, Margaret; Hutson, Elaine; Stevenson, Max

2004-01-01

We examine the return distributions of 332 funds of hedge funds and associated indices. Over half of the sample is significantly skewed according to the skewness statistic, and these are split 50/50 positive and negative. However, we argue that the skewness statistic can lead to erroneous inferences regarding the nature of the return distribution, because the test statistic is based on the normal distribution. Using a series of tests that make minimal assumptions about the shape of the ...

Numeraire Invariance and application to Option Pricing and Hedging

NARCIS (Netherlands)

Jamshidian, F.; Vanmaele, Michèle; Deelstra, Griselda; De Schepper, Ann; Dhaene, Jan; Reynaerts, Huguette; Schoutens, Wim; Van Goethem, Paul

2008-01-01

Numeraire invariance is a well-known technique in option pricing and hedging theory. It takes a convenient asset as the numeraire, as if it were the medium of exchange, and expresses all other asset and option prices in units of this numeraire. Since the price of the numeraire relative to itself is

Risk & Hedging Behavior: The Role and Determinants of Latent Heterogeneity

NARCIS (Netherlands)

Pennings, J.M.E.; Garcia, P.

2010-01-01

The notion of heterogeneous behavior is well grounded in economic theory. Recently it has been shown in a hedging context that the influence of risk attitudes and risk perceptions varies for different segments using a generalized mixture regression model. Here, using recently developed individual

Treatment with grass allergen peptides improves symptoms of grass pollen-induced allergic rhinoconjunctivitis.

Science.gov (United States)

Ellis, Anne K; Frankish, Charles W; O'Hehir, Robyn E; Armstrong, Kristen; Steacy, Lisa; Larché, Mark; Hafner, Roderick P

2017-08-01

Synthetic peptide immunoregulatory epitopes are a new class of immunotherapy to treat allergic rhinoconjunctivitis (ARC). Grass allergen peptides, comprising 7 synthetic T-cell epitopes derived from Cyn d 1, Lol p 5, Dac g 5, Hol l 5, and Phl p 5, is investigated for treatment of grass pollen-induced ARC. We sought to evaluate the efficacy, safety, and tolerability of intradermally administered grass allergen peptides. A multicenter, randomized, double-blind, placebo-controlled study evaluated 3 regimens of grass allergen peptides versus placebo in patients with grass pollen-induced allergy (18-65 years). After a 4-day baseline challenge to rye grass in the environmental exposure unit (EEU), subjects were randomized to receive grass allergen peptides at 6 nmol at 2-week intervals for a total of 8 doses (8x6Q2W), grass allergen peptides at 12 nmol at 4-week intervals for a total of 4 doses (4x12Q4W), or grass allergen peptides at 12 nmol at 2-week intervals for a total of 8 doses (8x12Q2W) or placebo and treated before the grass pollen season. The primary efficacy end point was change from baseline in total rhinoconjunctivitis symptom score across days 2 to 4 of a 4-day posttreatment challenge (PTC) in the EEU after the grass pollen season. Secondary efficacy end points and safety were also assessed. Two hundred eighty-two subjects were randomized. Significantly greater improvement (reduction of total rhinoconjunctivitis symptom score from baseline to PTC) occurred across days 2 to 4 with grass allergen peptide 8x6Q2W versus placebo (-5.4 vs -3.8, respectively; P = .0346). Greater improvement at PTC also occurred for grass allergen peptide 8x6Q2W versus placebo (P = .0403) in patients with more symptomatic ARC. No safety signals were detected. Grass allergen peptide 8x6Q2W significantly improved ARC symptoms after rye grass allergen challenge in an EEU with an acceptable safety profile. Copyright © 2017 American Academy of Allergy, Asthma & Immunology

Modeling seasonal water balance based on catchments' hedging strategy on evapotranspiration for climate seasonality

Science.gov (United States)

Wu, S.; Zhao, J.; Wang, H.

2017-12-01

This paper develops a seasonal water balance model based on the hypothesis that natural catchments utilize hedging strategy on evapotranspiration for climate seasonality. According to the monthly aridity index, one year is split into wet season and dry season. A seasonal water balance model is developed by analogy to a two-stage reservoir operation model, in which seasonal rainfall infiltration, evapotranspiration and saturation-excess runoff is corresponding to the inflow, release and surplus of the catchment system. Then the optimal hedging between wet season and dry season evapotranspiration is analytically derived with marginal benefit principle. Water budget data sets of 320 catchments in the United States covering the period from 1980 to 2010 are used to evaluate the performance of this model. The Nash-Sutcliffe Efficiency coefficient for evapotranspiration is higher than 0.5 in 84% of the study catchments; while the runoff is 87%. This paper validates catchments' hedging strategy on evapotranspiration for climate seasonality and shows its potential application for seasonal water balance, which is valuable for water resources planning and management.

Renewable energy as a natural gas price hedge: the case of wind

International Nuclear Information System (INIS)

Berry, David

2005-01-01

Electric utilities use natural gas to fuel many of their power plants, especially those plants which provide electricity at peak and intermediate hours. Natural gas prices are highly volatile and have shown a general upward trend. Wind energy can provide a cost-effective hedge against natural gas price volatility or price increases. This conclusion is based on analysis of the costs of marginal conventional generation given the historical probability distribution of natural gas prices, the cost of wind energy, wind integration costs, transmission costs for wind energy, the capacity value of wind, and environmental benefits of wind energy for a hypothetical utility in the Southwestern United States. The efficacy of using wind energy as a hedge at a particular utility will depend on site specific conditions

Hedge, redução de volatilidade dos lucros e o efeito sobre o imposto de renda das companhias abertas brasileiras

Directory of Open Access Journals (Sweden)

Valdir de Jesus Lameira

2005-08-01

Full Text Available Neste artigo, procurou-se identificar se as companhias abertas brasileiras teriam conseguido benefícios fiscais ao fazer hedge, fato esse derivado de uma expectativa de queda da sua carga tributária (Imposto de Renda a pagar. Com esse objetivo, inicialmente pesquisou-se em que situações have-ria possibilidade de geração desse benefício. Após essa revisão, foram estudadas situações em que a companhia tivesse grande volatilidade de seus resultados e os efeitos que o hedge traria no valor do I.R. a ser pago. Assim, pôde-se mensurar o efeito do resultado do hedge na carga tributária dessas companhias nesse período, simulando uma situação teórica para melhor evidenciarem-se os efeitos resultantes dessa prática. Posteriormente, utilizouse uma regressão linear múltipla para relacionar o valor do imposto de renda pago por companhias abertas brasileiras no ano de 2003 com os valores de hedge em 2002 e 2003 e os prejuízos acumulados em 2002. Os resultados são fundamentados em vasta bibliografia referente ao assunto.In this article we try to identify if Brazilian public companies hedge in response to tax incentives. With this goal, we first identify in which conditions the hedge causes reductions in tax obligations. Next, we study theoretical situations in which the companies' financial results change from great losses to great profits and we observe the impact in the companies' tax liabilities. Finally, we observe the results of a regression that tries to explain the tax obligations in 2003 in function of the hedge values in 2002, 2003 and the net operational losses in 2002. We conclude that it is possible to hedge in response to tax benefits in some special situations. Our results and conclusions are supported by other studies.

A Portrait of Hedge Fund Investors: Flows, Performance and Smart Money

NARCIS (Netherlands)

G. Baquero; M.J.C.M. Verbeek (Marno)

2005-01-01

textabstractWe explore the flow-performance interrelation by explicitly separating the investment and divestment decisions of hedge fund investors. The results show that different determinants and evaluation horizons underlie both decisions. While money inflows are sensitive to past long-run

Arbitrage and Hedging in a non probabilistic framework

OpenAIRE

Alvarez, Alexander; Ferrando, Sebastian; Olivares, Pablo

2011-01-01

The paper studies the concepts of hedging and arbitrage in a non probabilistic framework. It provides conditions for non probabilistic arbitrage based on the topological structure of the trajectory space and makes connections with the usual notion of arbitrage. Several examples illustrate the non probabilistic arbitrage as well perfect replication of options under continuous and discontinuous trajectories, the results can then be applied in probabilistic models path by path. The approach is r...

Hedge fund replication with a genetic algorithm: breeding a usable mousetrap

Czech Academy of Sciences Publication Activity Database

Payne, B. C.; Trešl, Jiří

2015-01-01

Roč. 15, č. 10 (2015), s. 1705-1726 ISSN 1469-7688 R&D Projects: GA ČR(CZ) GA14-31783S Institutional support: RVO:67985998 Keywords : hedge funds * replication * genetic algorithm Subject RIV: AH - Economics Impact factor: 0.794, year: 2015

The Case for Gold Revisited: A Safe Haven Or A Hedge ?

Directory of Open Access Journals (Sweden)

Sudi Apak

2012-09-01

Full Text Available This paper attempts to analyze the relation among gold prices and other macroeconomic and financial variables and addresses the question whether gold is a safe haven or a hedge for investors. The study investigates the relationship by using an econometric analysis for top gold exporter and importer countries, for a sample period of 11 years from 2000 to 2011. The results are twofold (i return of silver, USD returns and change in the volatility index influences gold returns positively whereas, Swiss Franc and Canadian Dollar returns influence gold returns negatively regardless of presence of the 2008 crisis. (ii In times of stress, our findings indicate that Swiss Franc, Norwegian Krone and Canadian Dollar function as haven whereas, on average, Swiss Franc, Canadian Dollar and 10 year US treasuries function as a hedge against gold but the results show no evidence for the US dollar.  

18 CFR 367.1760 - Account 176, Derivative instrument assets-Hedges.

Science.gov (United States)

2010-04-01

... change in the fair value of derivative instrument assets designated by the service company as cash flow... flow hedge it will record the change in the fair value of the derivative instrument in this account... must record the change in the fair value of the derivative instrument in this account with a concurrent...

Analysis of Nova 1 strategy formed by barrier options and its application in hedging against a price drop in oil market

Directory of Open Access Journals (Sweden)

Michal Šoltés

2015-12-01

Full Text Available This paper investigates hedging analysis against an underlying price drop by using the Nova 1 strategy formed by standard vanilla and barrier options. There are used European down and knock-in put options together with barrier call options. Derived income functions from the secured positions in analytical expressions are presented. Based on the theoretical results, the hedged portfolio is applied to SPDR SandP Oil and Gas Exploration and Production ETF. The proposed hedging variants are analysed and compared with the recommendation of the best possibilities for investors.

Institutional investor activism : Hedge funds and private equity, economics and regulation

NARCIS (Netherlands)

Mc Cahery, Joseph; Bratton, W.

2015-01-01

The increase in institutional ownership of recent decades has been accompanied by an enhanced role played by institutions in monitoring companies’ corporate governance behaviour. Activist hedge funds and private equity firms have achieved a degree of success in actively shaping the business plans of

Survival, Look-Ahead Bias and the Persistence in Hedge Fund Performance

NARCIS (Netherlands)

Baquero, G.; Ter Horst, J.R.; Verbeek, M.J.C.M.

2002-01-01

Hedge funds databases are typicall subject to high attrition rates because of fund termination and self-selection.Even when all funds are included up to their last available return, one cannot prevent that ex post conditioning biases affect standard estimates of performance persistence.In this paper

26 CFR 1.988-5 - Section 988(d) hedging transactions.

Science.gov (United States)

2010-04-01

... under the terms of the hedge to acquire the currency used to make payments under the qualifying debt.... (a) Integration of a nonfunctional currency debt instrument and a § 1.988-5(a) hedge—(1) In general... currency denominated debt instrument, such instrument shall be subject to the rules of § 1.988-2(b). (2...

Hedging electricity price volatility using nuclear power

International Nuclear Information System (INIS)

Mari, Carlo

2014-01-01

Highlights: • Nuclear power is an important asset to reduce the volatility of electricity prices. • Unpredictability of fossil fuels and carbon prices makes power prices very volatile. • The dynamics of fossil fuels and carbon prices is described by Brownian motions. • LCOE values, volatilities and correlations are obtained via Monte Carlo simulations. • Optimal portfolios of generating technologies are get using a mean–variance approach. - Abstract: The analysis presented in this paper aims to put in some evidence the role of nuclear power as hedging asset against the volatility of electricity prices. The unpredictability of natural gas and coal market prices as well as the uncertainty in environmental policies may affect power generating costs, thus enhancing volatility in electricity market prices. The nuclear option, allowing to generate electricity without carbon emissions, offers the possibility to reduce the volatility of electricity prices through optimal diversification of power generating technologies. This paper provides a methodological scheme to plan well diversified “portfolios” of generating capacity that minimize the electricity price risk induced by random movements of fossil fuels market prices and by unpredictable fluctuations of carbon credits prices. The analysis is developed within a stochastic environment in which the dynamics of fuel prices as well as the dynamics of carbon credits prices is assumed to evolve in time according to well defined Brownian processes. Starting from market data and using Monte Carlo techniques to simulate generating cost values, the hedging argument is developed by selecting optimal portfolio of power generating technologies using a mean–variance approach

Practical hedging and gas purchasing strategies for end-users

International Nuclear Information System (INIS)

Rosenzweig, J.

1995-01-01

Characteristics of the gas portfolio were described and its purpose was discussed in terms of diversification, risk reduction and flexibility. Tools to adjust the portfolio were discussed in terms of swaps and futures. Advantages and disadvantages of exchange and off-exchange traded instruments were outlined. Turning basis gas into a published indexed price, otherwise known as hedging, was explained. The market players ( banks, dealers, brokers) and their roles were described

Pseudo Control Hedging and its Application for Safe Flight Envelope Protection

NARCIS (Netherlands)

Lombaerts, T.J.J.; Looye, G.H.N.; Chu, Q.P.; Mulder, J.A.

2010-01-01

This paper describes how the previously developed concept of Pseudo Control Hedging (PCH) can be integrated in a Fault Tolerant Flight Controller (FTFC) as a safe flight envelope protection system of the first degree. This PCH algorithm adapts the reference model for the system output in case of

Pricing and hedging of arithmetic Asian options via the Edgeworth series expansion approach

Directory of Open Access Journals (Sweden)

Weiping Li

2016-03-01

Full Text Available In this paper, we derive a pricing formula for arithmetic Asian options by using the Edgeworth series expansion. Our pricing formula consists of a Black-Scholes-Merton type formula and a finite sum with the estimation of the remainder term. Moreover, we present explicitly a method to compute each term in our pricing formula. The hedging formulas (greek letters for the arithmetic Asian options are obtained as well. Our formulas for the long lasting question on pricing and hedging arithmetic Asian options are easy to implement with enough accuracy. Our numerical illustration shows that the arithmetic Asian options worths less than the European options under the standard Black-Scholes assumptions, verifies theoretically that the volatility of the arithmetic average is less than the one of the underlying assets, and also discovers an interesting phenomena that the arithmetic Asian option for large fixed strikes such as stocks has higher volatility (elasticity than the plain European option. However, the elasticity of the arithmetic Asian options for small fixed strikes as trading in currencies and commodity products is much less than the elasticity of the plain European option. These findings are consistent with the ones from the hedgings with respect to the time to expiration, the strike, the present underlying asset price, the interest rate and the volatility.

SQ grass sublingual allergy immunotherapy tablet for disease-modifying treatment of grass pollen allergic rhinoconjunctivitis

DEFF Research Database (Denmark)

Dahl, Ronald; Roberts, Graham; de Blic, Jacques

2016-01-01

BACKGROUND: Allergy immunotherapy is a treatment option for allergic rhinoconjunctivitis (ARC). It is unique compared with pharmacotherapy in that it modifies the immunologic pathways that elicit an allergic response. The SQ Timothy grass sublingual immunotherapy (SLIT) tablet is approved in North...... America and throughout Europe for the treatment of adults and children (≥5 years old) with grass pollen-induced ARC. OBJECTIVE: The clinical evidence for the use of SQ grass SLIT-tablet as a disease-modifying treatment for grass pollen ARC is discussed in this review. METHODS: The review included...... the suitability of SQ grass SLIT-tablet for patients with clinically relevant symptoms to multiple Pooideae grass species, single-season efficacy, safety, adherence, coseasonal initiation, and cost-effectiveness. The data from the long-term SQ grass SLIT-tablet clinical trial that evaluated a clinical effect 2...

Making renewable energy competitive in India: Reducing financing costs via a government-sponsored hedging facility

International Nuclear Information System (INIS)

Farooquee, Arsalan Ali; Shrimali, Gireesh

2016-01-01

In India, a significant barrier to market-competitiveness of renewable energy is a shortage of attractive debt. Domestic debt has high cost, short tenors, and variable interest rates, adding 30% to the cost of renewable energy compared to renewable energy projects elsewhere. Foreign debt is as expensive as domestic debt because it requires costly market-based currency hedging solutions. We investigate a government-sponsored foreign exchange facility as an alternative to reducing hedging costs. Using the geometric Brownian motion (GBM) as a representative stochastic model of the INR–USD foreign exchange rate, we find that the expected cost of providing a currency hedge via this facility is 3.5 percentage points, 50% lower than market. This leads to an up to 9% reduction in the per unit cost of renewable energy. However, this requires the government to manage the risks related to unexpected currency movements appropriately. One option to manage these risks is via a capital buffer; for the facility to obtain India's sovereign rating, the capital buffer would need to be almost 30% of the underlying loan. Our findings have significant policy implications given that the Indian government can use this facility to make renewable energy more competitive and, therefore, hasten its deployment. - Highlights: • We analyze a government-sponsored foreign exchange facility in India. •We use geometric Brownian motion to represent the INR–USD exchange rate. •This facility can reduce the currency hedging costs by 50%. •This facility can reduce the levelized cost of renewable energy by 9%. •The capital buffer to reach India's sovereign rating is 30% of the original loan.

Descriptive Analysis on Flouting and Hedging of Conversational Maxims in the “Post Grad” Movie

Directory of Open Access Journals (Sweden)

Nastiti Rokhmania

2012-11-01

Full Text Available This research is focused on analyzing flouting and hedging of conversational maxim of utterances used by the main characters in “Post Grad” movie. Conversational maxims are the rules of cooperative principle categorized into four categories; Maxim of Quality, Maxim of Quantity, Maxim of Relevance, and Maxim of Manner. If these maxims are used in conversations, the conversations can go smoothly. However, people often break the maxims overtly (flouting maxim and sometimes break the maxims secretly (hedging maxims when they make a conversation. This research is conducted using descriptive qualitative method based on the theory known as Grice’s Maxims. The data are in form of utterances used by the characters in “Post Grad” movie. The data analysis reveals some finding covering the formulated research question. The maxims are flouted when the speaker breaks some conversational maxims when using the utterances in the form of rhetorical strategies, such as tautology, metaphor, hyperbole, irony, and rhetorical question. On the other hand, conversational maxims are also hedged when the information is not totally accurate or unclearly stated but seems informative, well-founded, and relevant.

GUI development for GRASS GIS

Directory of Open Access Journals (Sweden)

Martin Landa

2007-12-01

Full Text Available This article discusses GUI development for GRASS GIS. Sophisticated native GUI for GRASS is one of the key points (besides the new 2D/3D raster library, vector architecture improvements, etc. for the future development of GRASS. In 2006 the GRASS development team decided to start working on the new generation of GUI instead of improving the current GUI based on Tcl/Tk.

Genome sequence analysis of the model grass Brachypodium distachyon: insights into grass genome evolution

Energy Technology Data Exchange (ETDEWEB)

Schulman, Al

2009-08-09

Three subfamilies of grasses, the Erhardtoideae (rice), the Panicoideae (maize, sorghum, sugar cane and millet), and the Pooideae (wheat, barley and cool season forage grasses) provide the basis of human nutrition and are poised to become major sources of renewable energy. Here we describe the complete genome sequence of the wild grass Brachypodium distachyon (Brachypodium), the first member of the Pooideae subfamily to be completely sequenced. Comparison of the Brachypodium, rice and sorghum genomes reveals a precise sequence- based history of genome evolution across a broad diversity of the grass family and identifies nested insertions of whole chromosomes into centromeric regions as a predominant mechanism driving chromosome evolution in the grasses. The relatively compact genome of Brachypodium is maintained by a balance of retroelement replication and loss. The complete genome sequence of Brachypodium, coupled to its exceptional promise as a model system for grass research, will support the development of new energy and food crops

Arbitrage hedging strategy and one more explanation of the volatility smile

OpenAIRE

Mikhail Martynov; Olga Rozanova

2011-01-01

We present an explicit hedging strategy, which enables to prove arbitrageness of market incorporating at least two assets depending on the same random factor. The implied Black-Scholes volatility, computed taking into account the form of the graph of the option price, related to our strategy, demonstrates the "skewness" inherent to the observational data.

Testing Commodities as Safe Haven and Hedging Instrument on ASEAN's Five Stock Markets

Directory of Open Access Journals (Sweden)

Robiyanto Robiyanto

2017-08-01

Full Text Available This study attempts to analyze commodity market instruments such as gold, silver, platinum, palladium, and West Texas Intermediate (WTI crude oil’s potential as hedge and safe haven toward some stock markets in South East Asia such as in Indonesia, Singapore, Malaysia, Philippines, and Thailand. To analyze the data, GARCH (1,1 was applied. The research findings showed that gold, silver, platinum, palladium, and WTI could not play their role as hedging instrument for five South East Asian capital markets. WTI could act as a robust safe haven for most South East Asian capital markets. Gold could do the role as a robust safe haven in Singapore and Malaysia, whereas, platinum and silver consistently could be safe haven only for Singapore Stock Exchange. Palladium could only be safe haven for Philippines Stock Exchange.

Fuzzy linguistic hedges for the selection of manufacturing process for prosthetic sockets

Directory of Open Access Journals (Sweden)

Richa Pandey

2014-08-01

Full Text Available In this paper, a comparison is presented between two prime methods of producing prosthetic sockets by using the fuzzy linguistic hedges approach on the qualitative feedback of Indian prosthetic users. Recent trends indicate that the Indian manufacturers have tried to adopt the newer technologies like reverse engineering (RE approach to achieve the desired goals. However, the satisfaction of the user is of utmost importance for the unique and customized products for rehabilitation. In order to analyze the effectiveness of the manufacturing approaches, user case studies are taken, based on the linguistic feedbacks, and a comparative study is conducted. Thirteen users from four different manufacturing units are taken for study and sockets made by conventional as well as RE are experimented. Fuzzy membership functions are constructed using the linguistic hedges based on the user feedbacks. An analytical hierarchy process (AHP is applied to arrive at a decision to select the manufacturing process for user satisfaction and manufacturing excellence.

Turkish Accounting Standards, IAS - 39 "Financial Instruments: Recognition and Measurement" Under the Cash Flow Hedge Derivative Products Use: The Case of Forward

Directory of Open Access Journals (Sweden)

Emine ÇINA BAL

2013-06-01

Full Text Available Businesses face interest rate, exchange rate, liquidity, use derivative financial instruments to hedge against such risks. Forward transactions with derivative financial instruments, the non-organized markets, interest rates pre-determined future date, foreign currency contracts that contain delivery of goods as well as financial assets. Cash flow hedge that forms the subject of this study, a recognized asset or liability or a highly probable forecast transaction and the net profit or loss attributable to a particular risk of affecting the nature of a cash flow hedge to hedge changes in the process. Study the case of the application of foreign money has a tangible fixed asset purchases. Related to the purchase of tangible fixed assets at future foreign mercenaries were forward contracts to hedge the cash flow risk. Forward contracts, principal accounts on the balance sheet in accordance with IAS 39 Standard, derivative financial instruments are shown as fixed assets. The fair value of the contract during the contract period at the end of the period to show the valuation differences arising from the valuation of equity shown in the balance sheet. Net valuation differences arising from the contract are accounted for by two separate options. The first option, the net costs associated with the asset valuation difference. The second option is deducted from the amount of depreciation for the asset at the end of the period.

Mandatory Disclosure and Operational Risk: Evidence from Hedge Fund Registration

OpenAIRE

Stephen Brown; William Goetzmann; Bing Liang; Christopher Schwarz

2006-01-01

Mandatory disclosure is a regulatory tool intended to allow market participants to assess operational risk. We examine the value of disclosure through the controversial SEC requirement, since overturned, which required major hedge funds to register as investment advisors and file Form ADV disclosures. Leverage and ownership structures suggest that lenders and equity investors were already aware of operational risk. However, operational risk does not mediate flow-performance relationships. Inv...

The Buyers’ Perspective on Security Design: Hedge Funds and Convertible Bond Call Provisions

NARCIS (Netherlands)

B.D. Grundy (Bruce); P. Verwijmeren (Patrick)

2016-01-01

textabstractWe provide evidence that security design reflects the interplay of capital supplier and security issuer preferences. While call provisions have historically been the default option in convertible security design, only a minority of post-2005 issues are callable. Because hedge funds

Hedging Behavior in Small and Medium-sized Enterprises: The Role of Unobserved Heterogeneity

NARCIS (Netherlands)

Pennings, J.M.E.; Garcia, P.

2004-01-01

Abstract We investigate factors that drive derivative usage in small and medium-sized enterprises (SMEs). The influence of these factors on hedging behavior cannot a priori be assumed equal for all SMEs. To address this heterogeneity, a generalized mixture regression model is used which classifies

Bet hedging based cooperation can limit kin selection and form a basis for mutualism.

Science.gov (United States)

Uitdehaag, Joost C M

2011-07-07

Mutualism is a mechanism of cooperation in which partners that differ help each other. As such, mutualism opposes mechanisms of kin selection and tag-based selection (for example the green beard mechanism), which are based on giving exclusive help to partners that are related or carry the same tag. In contrast to kin selection, which is a basis for parochialism and intergroup warfare, mutualism can therefore be regarded as a mechanism that drives peaceful coexistence between different groups and individuals. Here the competition between mutualism and kin (tag) selection is studied. In a model where kin selection and tag-based selection are dominant, mutualism is promoted by introducing environmental fluctuations. These fluctuations cause reduction in reproductive success by the mechanism of variance discount. The best strategy to counter variance discount is to share with agents who experience the most anticorrelated fluctuations, a strategy called bet hedging. In this way, bet hedging stimulates cooperation with the most unrelated partners, which is a basis for mutualism. Analytic results and simulations reveal that, if this effect is large enough, mutualistic strategies can dominate kin selective strategies. In addition, mutants of these mutualistic strategies that experience fluctuations that are more anticorrelated to their partner, can outcompete wild type, which can lead to the evolution of specialization. In this way, the evolutionary success of mutualistic strategies can be explained by bet hedging-based cooperation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Five-dimensional Monopole Equation with Hedge-Hog Ansatz and Abel's Differential Equation

OpenAIRE

Kihara, Hironobu

2008-01-01

We review the generalized monopole in the five-dimensional Euclidean space. A numerical solution with the Hedge-Hog ansatz is studied. The Bogomol'nyi equation becomes a second order autonomous non-linear differential equation. The equation can be translated into the Abel's differential equation of the second kind and is an algebraic differential equation.

The Effect of Shortfall as a Risk measure for Portfolios with Hedge Funds

NARCIS (Netherlands)

Lucas, A.; Siegmann, A.H.

2008-01-01

Current research suggests that the large downside risk in hedge fund returns disqualifies the variance as an appropriate risk measure. For example, one can easily construct portfolios with nonlinear pay-offs that have both a high Sharpe ratio and a high downside risk. This paper examines the

Market completeness. How options affect hedging and investments in the electricity sector

International Nuclear Information System (INIS)

Willems, Bert; Morbee, Joris

2010-01-01

The high volatility of electricity markets gives producers and retailers an incentive to hedge their exposure to electricity prices by buying and selling derivatives. This paper studies how welfare and investment incentives are affected when an increasing number of derivatives are introduced. It develops an equilibrium model of the electricity market with risk averse firms and a set of traded financial products, more specifically: a forward contract and an increasing number of options. We first show that aggregate welfare (the sum of individual firms' utility) increases with the number of derivatives offered, although most of the benefits are captured with one to three options. Secondly, power plant investments typically increase because additional derivatives enable better hedging of investments. However, the availability of derivatives sometimes leads to 'crowding-out' of physical investments because firms' limited risk-taking capabilities are being used to speculate on financial markets. Finally, we illustrate that players basing their investment decisions on risk-free probabilities inferred from market prices, may significantly overinvest when markets are not sufficiently complete. (author)

Analysis of the soil food web structure under grass and grass clover

NARCIS (Netherlands)

Eekeren, van N.J.M.; Smeding, F.W.; Vries, de F.T.; Bloem, J.

2006-01-01

The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil

The Economics of Hedge Funds: Alpha, Fees, Leverage, and Valuation

OpenAIRE

Yingcong Lan; Neng Wang; Jinqiang Yang

2011-01-01

Hedge fund managers are compensated via management fees on the assets under management (AUM) and incentive fees indexed to the high-water mark (HWM). We study the effects of managerial skills (alpha) and compensation on dynamic leverage choices and the valuation of fees and investors' payoffs. Increasing the investment allocation to the alpha-generating strategy typically lowers the fund's risk-adjusted excess return due to frictions such as price pressure. When the manager is only paid via m...

Meadow-grass gall midge

DEFF Research Database (Denmark)

Hansen, Lars Monrad

The area with meadow-grass (Poa pratensis, L.) grown for seed production in Den-mark is a significant proportion of the entire seed production. The meadow-grass gall midge (Mayetiola schoberi, Barnes 1958) is of considerable economic importance since powerful attacks can reduce the yield...

Robustness of Quadratic Hedging Strategies in Finance via Backward Stochastic Differential Equations with Jumps

International Nuclear Information System (INIS)

Di Nunno, Giulia; Khedher, Asma; Vanmaele, Michèle

2015-01-01

We consider a backward stochastic differential equation with jumps (BSDEJ) which is driven by a Brownian motion and a Poisson random measure. We present two candidate-approximations to this BSDEJ and we prove that the solution of each candidate-approximation converges to the solution of the original BSDEJ in a space which we specify. We use this result to investigate in further detail the consequences of the choice of the model to (partial) hedging in incomplete markets in finance. As an application, we consider models in which the small variations in the price dynamics are modeled with a Poisson random measure with infinite activity and models in which these small variations are modeled with a Brownian motion or are cut off. Using the convergence results on BSDEJs, we show that quadratic hedging strategies are robust towards the approximation of the market prices and we derive an estimation of the model risk

Robustness of Quadratic Hedging Strategies in Finance via Backward Stochastic Differential Equations with Jumps

Energy Technology Data Exchange (ETDEWEB)

Di Nunno, Giulia, E-mail: giulian@math.uio.no [University of Oslo, Center of Mathematics for Applications (Norway); Khedher, Asma, E-mail: asma.khedher@tum.de [Technische Universität München, Chair of Mathematical Finance (Germany); Vanmaele, Michèle, E-mail: michele.vanmaele@ugent.be [Ghent University, Department of Applied Mathematics, Computer Science and Statistics (Belgium)

2015-12-15

We consider a backward stochastic differential equation with jumps (BSDEJ) which is driven by a Brownian motion and a Poisson random measure. We present two candidate-approximations to this BSDEJ and we prove that the solution of each candidate-approximation converges to the solution of the original BSDEJ in a space which we specify. We use this result to investigate in further detail the consequences of the choice of the model to (partial) hedging in incomplete markets in finance. As an application, we consider models in which the small variations in the price dynamics are modeled with a Poisson random measure with infinite activity and models in which these small variations are modeled with a Brownian motion or are cut off. Using the convergence results on BSDEJs, we show that quadratic hedging strategies are robust towards the approximation of the market prices and we derive an estimation of the model risk.

Grass-Shrub Associations over a Precipitation Gradient and Their Implications for Restoration in the Great Basin, USA.

Directory of Open Access Journals (Sweden)

Maike F Holthuijzen

Full Text Available As environmental stress increases positive (facilitative plant interactions often predominate. Plant-plant associations (or lack thereof can indicate whether certain plant species favor particular types of microsites (e.g., shrub canopies or plant-free interspaces and can provide valuable insights into whether "nurse plants" will contribute to seeding or planting success during ecological restoration. It can be difficult, however, to anticipate how relationships between nurse plants and plants used for restoration may change over large-ranging, regional stress gradients. We investigated associations between the shrub, Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis, and three common native grasses (Poa secunda, Elymus elymoides, and Pseudoroegneria spicata, representing short-, medium-, and deep-rooted growth forms, respectively, across an annual rainfall gradient (220-350 mm in the Great Basin, USA. We hypothesized that positive shrub-grass relationships would become more frequent at lower rainfall levels, as indicated by greater cover of grasses in shrub canopies than vegetation-free interspaces. We sampled aerial cover, density, height, basal width, grazing status, and reproductive status of perennial grasses in canopies and interspaces of 25-33 sagebrush individuals at 32 sites along a rainfall gradient. We found that aerial cover of the shallow rooted grass, P. secunda, was higher in sagebrush canopy than interspace microsites at lower levels of rainfall. Cover and density of the medium-rooted grass, E. elymoides were higher in sagebrush canopies than interspaces at all but the highest rainfall levels. Neither annual rainfall nor sagebrush canopy microsite significantly affected P. spicata cover. E. elymoides and P. spicata plants were taller, narrower, and less likely to be grazed in shrub canopy microsites than interspaces. Our results suggest that exploring sagebrush canopy microsites for restoration of native perennial

Scab severity in relation to hedge pruning pecan trees in the Southeastern USA

Science.gov (United States)

Scab is the most damaging disease of pecan in the Southeastern USA. Pecan trees are tall (up to 30+ m), and managing disease in the upper canopy is problematic. Hedge pruning trees to ~12 m is being explored to facilitate efficacy of ground-based fungicide sprays, but resulting vigorous shoot growth...

Nutritional value of cabbage and kikuyu grass as food for grass carp ...

African Journals Online (AJOL)

and digestibility coefficients were obtained for the protein, fibre, ash and fat contents of both ... Cabbage is a superior feed compared to grass for raising grass carp and a suitable low-cost alternative ... Materials and Methods ... from jumping out and was fitted with an air lift under- .... In: Aquatic weeds in South East Asia.

Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

Directory of Open Access Journals (Sweden)

Danijel Karolyi

2010-01-01

Full Text Available Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd was slower for silage than fresh grass. Gas production method (GP data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.

High green fodder yielding new grass varieties

OpenAIRE

C. Babu, K. Iyanar and A. Kalamani

2014-01-01

Two high biomass yielding forage grass varieties one each in Cumbu Napier hybrid and Guinea grass have been evolved at the Department of Forage Crops, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore and identified for release at national (All India) level as Cumbu Napier hybrid grass CO (BN) 5 and Guinea grass CO (GG) 3 during 2012 and 2013 respectively. Cumbu Napier hybrid grass CO (BN) 5 secured first rank at all national level with reference to green ...

Enhancing GRASS data communication with videographic technology

Energy Technology Data Exchange (ETDEWEB)

Sullivan, R.G. [Argonne National Lab., IL (United States); Gerdes, D.; Youngs, D. [Army Construction Engineering Research Lab., Champaign, IL (United States)

1992-07-01

Research at Argonne National Laboratory and the US Army Construction Engineering Research Laboratory has shown that computer videographic technology can be used to assist visualization and communication of GIS-generated geographic information. Videographic tools can be used to make results of GRASS analyses clear to decision-makers and to public interest groups, as well as to help GRASS users visualize geographic data more easily. Useful videographic visualization tools include graphic overlay of GRASS layers onto panchromatic images, allowing landscape features to be associated with GIS classifications; draping of GIS layers onto terrain models to create shaded relief maps; and incorporation of photographic imagery into GIS graphics. Useful videographic communications capabilities include convenient, direct interface to video formats, allowing incorporation of live video into GRASS graphics and output of GRASS graphics to video; convenient output of high-quality slides and prints; and enhanced labeling and editing of GRASS images. Conversion of GRASS imagery to standard videographic file formats also facilitates incorporation of GRASS images into other software programs, such as database and work-processing packages.

Enhancing GRASS data communication with videographic technology

Energy Technology Data Exchange (ETDEWEB)

Sullivan, R.G. (Argonne National Lab., IL (United States)); Gerdes, D.; Youngs, D. (Army Construction Engineering Research Lab., Champaign, IL (United States))

1992-01-01

Research at Argonne National Laboratory and the US Army Construction Engineering Research Laboratory has shown that computer videographic technology can be used to assist visualization and communication of GIS-generated geographic information. Videographic tools can be used to make results of GRASS analyses clear to decision-makers and to public interest groups, as well as to help GRASS users visualize geographic data more easily. Useful videographic visualization tools include graphic overlay of GRASS layers onto panchromatic images, allowing landscape features to be associated with GIS classifications; draping of GIS layers onto terrain models to create shaded relief maps; and incorporation of photographic imagery into GIS graphics. Useful videographic communications capabilities include convenient, direct interface to video formats, allowing incorporation of live video into GRASS graphics and output of GRASS graphics to video; convenient output of high-quality slides and prints; and enhanced labeling and editing of GRASS images. Conversion of GRASS imagery to standard videographic file formats also facilitates incorporation of GRASS images into other software programs, such as database and work-processing packages.

Oil Price Volatility, Economic Growth and the Hedging Role of Renewable Energy

OpenAIRE

Rentschler, Jun E.

2013-01-01

This paper investigates the adverse effects of oil price volatility on economic activity and the extent to which countries can hedge against such effects by using renewable energy. By considering the Realized Volatility of oil prices, rather than following the standard approach of considering oil price shocks in levels, the effects of factor price uncertainty on economic activity are analy...

Fractionation of carbohydrate and protein content of some forage feeds of ruminants for nutritive evaluation.

Science.gov (United States)

Das, Lalatendu Keshary; Kundu, S S; Kumar, Dinesh; Datt, Chander

2015-02-01

To evaluate some forage feeds of ruminants in terms of their carbohydrate (CHO) and protein fractions using Cornell Net Carbohydrate and Protein System (CNCPS). Eleven ruminant feeds (six green fodders - maize, oat, sorghum, bajra, cowpea, berseem and five range herbages - para grass, guinea grass, hedge lucerne, setaria grass and hybrid napier) were selected for this study. Each feed was chemically analyzed for proximate principles (dry matter, crude protein [CP], ether extract, organic matter and ash), fiber fractions (neutral detergent fiber, acid detergent fiber, acid detergent lignin, cellulose and hemicellulose), primary CHO fractions (CHO, non-structural CHO, structural CHO and starch) and primary protein fractions (neutral detergent insoluble CP, acid detergent insoluble CP, non-protein nitrogen and soluble protein). The results were fitted to the equations of CNCPS to arrive at various CHO (CA - fast degrading, CB1 - intermediate degrading, CB2 - slow degrading and CC - non-degrading or unavailable) and protein (PA - instantaneously degrading, PB1 - fast degrading, PB2 - intermediate degrading, PB3 - slow degrading and PC - non-degrading or unavailable) fractions of test feeds. Among green fodders, cowpea and berseem had higher CA content while except hedge lucerne all range herbages had lower CA values. CB1 content of all feeds was low but similar. All feeds except cowpea, berseem, and hedge lucerne contained higher CB2 values. Oat among green fodders and hybrid napier among range herbages had lower CC fraction. Feeds such as bajra, cowpea, berseem and the setaria grass contained lower PA fraction. All green fodders had higher PB1 content except maize and cowpea while all range herbages had lower PB1 values except hedge lucerne. Para grass and hybrid napier contained exceptionally low PB2 fraction among all feeds. Low PC contents were reported in oat and berseem fodders. Based on our findings, it was concluded that feeds with similar CP and CHO content

Fractionation of carbohydrate and protein content of some forage feeds of ruminants for nutritive evaluation

Directory of Open Access Journals (Sweden)

Lalatendu Keshary Das

2015-02-01

Full Text Available Aim: To evaluate some forage feeds of ruminants in terms of their carbohydrate (CHO and protein fractions using Cornell Net Carbohydrate and Protein System (CNCPS. Materials and Methods: Eleven ruminant feeds (six green fodders - maize, oat, sorghum, bajra, cowpea, berseem and five range herbages - para grass, guinea grass, hedge lucerne, setaria grass and hybrid napier were selected for this study. Each feed was chemically analyzed for proximate principles (dry matter, crude protein [CP], ether extract, organic matter and ash, fiber fractions (neutral detergent fiber, acid detergent fiber, acid detergent lignin, cellulose and hemicellulose, primary CHO fractions (CHO, non-structural CHO, structural CHO and starch and primary protein fractions (neutral detergent insoluble CP, acid detergent insoluble CP, non-protein nitrogen and soluble protein. The results were fitted to the equations of CNCPS to arrive at various CHO (CA - fast degrading, CB1 - intermediate degrading, CB2 - slow degrading and CC - nondegrading or unavailable and protein (PA - instantaneously degrading, PB1 - fast degrading, PB2 - intermediate degrading, PB3 - slow degrading and PC - non-degrading or unavailable fractions of test feeds. Results: Among green fodders, cowpea and berseem had higher CA content while except hedge lucerne all range herbages had lower CA values. CB1 content of all feeds was low but similar. All feeds except cowpea, berseem, and hedge lucerne contained higher CB2 values. Oat among green fodders and hybrid napier among range herbages had lower CC fraction. Feeds such as bajra, cowpea, berseem and the setaria grass contained lower PA fraction. All green fodders had higher PB1 content except maize and cowpea while all range herbages had lower PB1 values except hedge lucerne. Para grass and hybrid napier contained exceptionally low PB2 fraction among all feeds. Low PC contents were reported in oat and berseem fodders. Conclusion: Based on our findings, it

Different techniques to study rumen fermentation characteristics of maturing grass and grass silage

NARCIS (Netherlands)

Cone, J.W.; Gelder, van A.H.; Soliman, I.A.; Visser, de H.; Vuuren, van A.M.

1999-01-01

Grass samples were harvested during the 1993 growing season after a precut on April 27, 1993 and were stored frozen or left to ensile in 30-L buckets. Effects on chemical composition and fermentation kinetics of the maturation of the grass and of ensiling were investigated. Chemical composition and

Public lending to private hedge funds is inefficient, unstable, unconstitutional and unanimously disagreeable

Directory of Open Access Journals (Sweden)

Sankarshan Acharya

2016-06-01

Full Text Available Public funds include federally insured deposits held under the custody of private banks, central bank loans and taxpayer funds. The principal finding of this paper is that lending such public funds through a private banking system to private hedge funds allied with the banks is inefficient, unstable, fundamentally unfair (unconstitutional and unanimously disagreeable. This finding is akin to the unanimously agreeable safe central banking policy (Acharya, 1991-2016 which, in dynamic general equilibrium, (a eliminates federal guarantee of bank deposits, (b offers every business enterprise and household an option to keep in the central bank any part of its deposits it wants to be held absolutely safely, (c completely deregulates all private banks without any privilege to rob public or private wealth like too-big-to-fail or too-big-to-be-jailed status or the power of market making and clearing. Safe central banking is the only way to make private banks responsible to hold sufficient capital to attract uninsured private deposits like the trading houses currently do. The private banks will then have complete freedom to lend their uninsured deposits to private hedge funds. The Volker Rule (NYT, January 30, 2010, incorporated in the Dodd-Frank Act of 2010, is an infeasible and unworkable band-aid for the moral-hazard driven systemic robbery of wealth creators wrought by the government-ordained private banking custody of public funds. The established systemic moral-hazard problem can be efficiently and constitutionally resolved only through unanimously agreeable safe central banking. Current proposals on overhauling of Fannie and Freddie made by various pundits of systemic robbery amount to a gargantuan amount of public lending to private hedge funds and, hence, inefficient, unstable, unconstitutional and unanimously disagreeable.

Breeding for Grass Seed Yield

DEFF Research Database (Denmark)

Boelt, Birte; Studer, Bruno

2010-01-01

Seed yield is a trait of major interest for many fodder and amenity grass species and has received increasing attention since seed multiplication is economically relevant for novel grass cultivars to compete in the commercial market. Although seed yield is a complex trait and affected...... by agricultural practices as well as environmental factors, traits related to seed production reveal considerable genetic variation, prerequisite for improvement by direct or indirect selection. This chapter first reports on the biological and physiological basics of the grass reproduction system, then highlights...... important aspects and components affecting the seed yield potential and the agronomic and environmental aspects affecting the utilization and realization of the seed yield potential. Finally, it discusses the potential of plant breeding to sustainably improve total seed yield in fodder and amenity grasses....

Post-ruminal digestibility of crude protein from grass and grass silages in cows

NARCIS (Netherlands)

Cone, J.W.; Gelder, van A.H.; Mathijssen-Kamman, A.A.; Hindle, V.A.

2006-01-01

Grass samples were grown on a clay or sandy soil, fertilised with 150 or 300 kg N/ha per year, and harvested on different days during two consecutive growing seasons. The grass samples were stored frozen or ensiled after wilting to approximately 250 or 450 g DM/kg. The recoveries of crude protein

Humanizing Finance by Hedging Property Values

Directory of Open Access Journals (Sweden)

Jaume Roig Hernando

2016-06-01

Full Text Available The recent financial crisis triggered the greatest recession since the 1930s and had a devastating impact on households’ wealth and on their capacity to reduce their indebtedness. In the aftermath, it became clear that there is significant room for improvement in property risk management. While there has been innovation in the management of corporate finance risk, real estate has lagged behind. Now is the time to expand the range of tools available for hedging households’ risks and, thus, to advance the democratization of finance. Property equity represents the major asset in households’ portfolios in developed and undeveloped countries. The present paper analyzes a set of potential innovations in real estate risk management, such as price level-adjusted mortgages, property derivatives, and home equity value insurance. Financial institutions, households, and governments should work together to improve the performance of the financial instruments available and, thus, to help mitigate the worst impacts of economic cycles.

[Life cycle of Gongylonema mucronatum Seurat, 1916, parasite of the African hedge-hog (author's transl)].

Science.gov (United States)

Quentin, J C; Seguignes, M

1979-01-01

The Gongylonematid Nematode parasite of the Tunisian hedge-hog has been identified as Gongylonema mucronatum Seurat, 1916. The infective larva has been obtained from Locusta migratoria as intermediate host. The larval characters of this Gongylonema link it to the species G. pulchrum.

Impact Of Foreign Currency Hedging On Firm Value Among Indian Corporates

OpenAIRE

Gupta, Amit

2016-01-01

Indian economy was opened for globalization in 1991 and Indian Rupee was deregulated in 1993 and subjected to market fluctuations. Indian Rupee was very volatile during the past decade due to global events like US subprime crisis (2007-2009), European sovereign debt crisis, Oil prices fluctuations and Fed monetary policy speculations to name few. This volatility has put pressure on Indian firms to manage their foreign currency exposure. Hedging and use of Foreign Currency Derivatives (FCD) is...

Martingale approach in pricing and hedging European options under regime-switching

OpenAIRE

Grigori N. Milstein; Vladimir Spokoiny

2011-01-01

The paper focuses on the problem of pricing and hedging a European contingent claim for an incomplete market model, in which evolution of price processes for a saving account and stocks depends on an observable Markov chain. The pricing function is evaluated using the martingale approach. The equivalent martingale measure is introduced in a way that the Markov chain remains the historical one, and the pricing function satisfies the Cauchy problem for a system of linear parabolic equations. It...

Risk Neutral Option Pricing With Neither Dynamic Hedging nor Complete Markets

OpenAIRE

Nassim N. Taleb

2014-01-01

Proof that under simple assumptions, such as constraints of Put-Call Parity, the probability measure for the valuation of a European option has the mean derived from the forward price which can, but does not have to be the risk-neutral one, under any general probability distribution, bypassing the Black-Scholes-Merton dynamic hedging argument, and without the requirement of complete markets and other strong assumptions. We confirm that the heuristics used by traders for centuries are both mor...

On Exponential Hedging and Related Quadratic Backward Stochastic Differential Equations

International Nuclear Information System (INIS)

Sekine, Jun

2006-01-01

The dual optimization problem for the exponential hedging problem is addressed with a cone constraint. Without boundedness conditions on the terminal payoff and the drift of the Ito-type controlled process, the backward stochastic differential equation, which has a quadratic growth term in the drift, is derived as a necessary and sufficient condition for optimality via a variational method and dynamic programming. Further, solvable situations are given, in which the value and the optimizer are expressed in closed forms with the help of the Clark-Haussmann-Ocone formula

Quantifying the value that energy efficiency and renewable energy provide as a hedge against volatile natural gas prices

Energy Technology Data Exchange (ETDEWEB)

Bolinger, Mark; Wiser, Ryan; Bachrach, Devra; Golove, William

2002-05-15

Advocates of energy efficiency and renewable energy have long argued that such technologies can mitigate fuel price risk within a resource portfolio. Such arguments--made with renewed vigor in the wake of unprecedented natural gas price volatility during the winter of 2000/2001--have mostly been qualitative in nature, however, with few attempts to actually quantify the price stability benefit that these sources provide. In evaluating this benefit, it is important to recognize that alternative price hedging instruments are available--in particular, gas-based financial derivatives (futures and swaps) and physical, fixed-price gas contracts. Whether energy efficiency and renewable energy can provide price stability at lower cost than these alternative means is therefore a key question for resource acquisition planners. In this paper we evaluate the cost of hedging gas price risk through financial hedging instruments. To do this, we compare the price of a 10-year natural gas swap (i.e., what it costs to lock in prices over the next 10 years) to a 10-year natural gas price forecast (i.e., what the market is expecting spot natural gas prices to be over the next 10 years). We find that over the past two years natural gas users have had to pay a premium as high as $0.76/mmBtu (0.53/242/kWh at an aggressive 7,000 Btu/kWh heat rate) over expected spot prices to lock in natural gas prices for the next 10 years. This incremental cost to hedge gas price risk exposure is potentially large enough - particularly if incorporated by policymakers and regulators into decision-making practices - to tip the scales away from new investments in variable-price, natural gas-fired generation and in favor of fixed-price investments in energy efficiency and renewable energy.

Not putting all their eggs in one basket: bet-hedging despite extraordinary annual reproductive output of desert tortoises

Science.gov (United States)

Lovich, Jeffrey E.; Ennen, Joshua R.; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Agha, Mickey; Loughran, Caleb L.; Bjurlin, Curtis; Austin, Meaghan; Madrak, Sheila V.

2015-01-01

Bet-hedging theory makes the counter-intuitive prediction that, if juvenile survival is low and unpredictable, organisms should consistently reduce short-term reproductive output to minimize the risk of reproductive failure in the long-term. We investigated the long-term reproductive output of an Agassiz's desert tortoise (Gopherus agassizii) population and conformance to a bet-hedging strategy of reproduction in an unpredictable but comparatively productive environment. Most females reproduced every year, even during periods of low precipitation and poor germination of food plants, and the mean percentage of reproducing females did not differ significantly on an annual basis. Although mean annual egg production (clutch size × clutch frequency) differed significantly among years, mean clutch size and mean clutch frequency remained relatively constant. During an El Niño year, mean annual egg production and mean annual clutch frequency were the highest ever reported for this species. Annual egg production was positively influenced by maternal body size but clutch size and clutch frequency were not. Our long-term results confirm earlier conclusions based on short-term research that desert tortoises have a bet-hedging strategy of producing small clutches almost every year. The risk of long-term reproductive failure is minimized in unpredictable environments, both through time by annually producing multiple small clutches over a long reproductive lifespan, even in years of low resource availability, and through space by depositing multiple annual clutches in different locations. The extraordinary annual reproductive output of this population appears to be the result of a typically high but unpredictable biomass of annual food plants at the site relative to tortoise habitat in dryer regions. Under the comparatively productive but unpredictable conditions, tortoises conform to predictions of a bet-hedging strategy of reproduction with relatively small but consistent

Quantifying the value that energy efficiency and renewable energy provide as a hedge against volatile natural gas prices

International Nuclear Information System (INIS)

Bolinger, Mark; Wiser, Ryan; Bachrach, Devra; Golove, William

2002-01-01

Advocates of energy efficiency and renewable energy have long argued that such technologies can mitigate fuel price risk within a resource portfolio. Such arguments-made with renewed vigor in the wake of unprecedented natural gas price volatility during the winter of 2000/2001-have mostly been qualitative in nature, however, with few attempts to actually quantify the price stability benefit that these sources provide. In evaluating this benefit, it is important to recognize that alternative price hedging instruments are available-in particular, gas-based financial derivatives (futures and swaps) and physical, fixed-price gas contracts. Whether energy efficiency and renewable energy can provide price stability at lower cost than these alternative means is therefore a key question for resource acquisition planners. In this paper we evaluate the cost of hedging gas price risk through financial hedging instruments. To do this, we compare the price of a 10-year natural gas swap (i.e., what it costs to lock in prices over the next 10 years) to a 10-year natural gas price forecast (i.e., what the market is expecting spot natural gas prices to be over the next 10 years). We find that over the past two years natural gas users have had to pay a premium as high as$0.76/mmBtu (0.53/242/kWh at an aggressive 7,000 Btu/kWh heat rate) over expected spot prices to lock in natural gas prices for the next 10 years. This incremental cost to hedge gas price risk exposure is potentially large enough - particularly if incorporated by policymakers and regulators into decision-making practices - to tip the scales away from new investments in variable-price, natural gas-fired generation and in favor of fixed-price investments in energy efficiency and renewable energy

Grass pollen immunotherapy induces highly cross-reactive IgG antibodies to group V allergen from different grass species

NARCIS (Netherlands)

van Ree, R.; Brewczyński, P. Z.; Tan, K. Y.; Mulder-Willems, H. J.; Widjaja, P.; Stapel, S. O.; Aalberse, R. C.; Kroon, A. M.

1995-01-01

Sera from two groups of patients receiving grass pollen immunotherapy were tested on IgG reactivity with group V allergen from six different grass species. One group of patients was treated with a mixture of 10 grass species, and the other with a mixture of five. Only Lolium perenne, Dactylis

Bet-hedging response to environmental variability, an intraspecific comparison.

Science.gov (United States)

Nevoux, Marie; Forcada, Jaume; Barbraud, Christophe; Croxall, John; Weimerskirchi, Henri

2010-08-01

A major challenge in ecology is to understand the impact of increased environmental variability on populations and ecosystems. To maximize their fitness in a variable environment, life history theory states that individuals should favor a bet-hedging strategy, involving a reduction of annual breeding performance and an increase in adult survival so that reproduction can be attempted over more years. As a result, evolution toward longer life span is expected to reduce the deleterious effects of extra variability on population growth, and consequently on the trait contributing the most to it (e.g., adult survival in long-lived species). To investigate this, we compared the life histories of two Black-browed Albatross (Thalassarche melanophrys) populations breeding at South Georgia (Atlantic Ocean) and Kerguelen (Indian Ocean), the former in an environment nearly three times more variable climatically (e.g., in sea surface temperature) than the latter. As predicted, individuals from South Georgia (in the more variable environment) showed significantly higher annual adult survival (0.959, SE = 0.003) but lower annual reproductive success (0.285 chick per pair, SE = 0.039) than birds from Kerguelen (survival = 0.925, SE = 0.004; breeding success = 0.694, SE = 0.027). In both populations, climatic conditions affected the breeding success and the survival of inexperienced breeders, whereas the survival of experienced breeders was unaffected. The strength of the climatic impact on survival of inexperienced breeders was very similar between the two populations, but the effect on breeding success was positively related to environmental variability. These results provide rare and compelling evidence to support bet-hedging underlying changes in life history traits as an adaptive response to environmental variability.

Spatiotemporal Variation in the Environmental Controls of C4-Grass Origin and Ecology: Insights from Grass-Pollen δ13C Data

Science.gov (United States)

Nelson, D. M.; Urban, M.; Hu, F.

2014-12-01

Understanding the environmental factors controlling the origin and shifting abundance of C4 grasses in Earth's history is useful for projecting the response of C4-grass dominated grasslands to future environmental change. Unfortunately, grass pollen is typically morphologically indistinct, making palynological analysis a blunt tool for studying C4-grasses in the paleorecord. δ13C of individual grass-pollen grains using a spooling wire microcombustion device interfaced with an isotope ratio mass spectrometer (Single Pollen Isotope Ratio AnaLysis, SPIRAL) overcomes this challenge and the potential biases of δ13C data from other substrates (e.g. leaf waxes). To assess the presence and relative abundance of C3- and C4-grass pollen in samples of unknown composition, we developed a hierarchical Bayesian model, trained with ~1,900 δ13C values from pollen grains of 31 grass species. Surface-sediment data from Africa, Australia, and North America demonstrate the reliability of this technique for quantifying C4-grass abundance on the landscape. To investigate the timing and control of the origin of C4-grasses we analyzed samples from the Oligocene-Miocene from Europe and from the Eocene from North America. Results indicate that C4 grasses appeared on the landscape of southwest Europe no later than the early Oligocene, implying that low atmospheric pCO2 may not have been the main driver and/or precondition for the development of C4 photosynthesis in the grass family. In contrast, we found no evidence for C4 grasses in the southeast United States before pCO2 fell. In application of SPIRAL to the late Quaternary, we found that shifts in pCO2 and moisture balance exerted key controls on the relative abundance of C3 and C4 grasses in Africa and Australia. Overall, our results imply that as in the past, future changes in the C3/C4 composition of grass-dominated ecosystems will likely exhibit striking spatiotemporal variability as a result of differing combinations of

Coping With a Rising Power: Vietnam’s Hedging Strategy Toward China

Science.gov (United States)

2018-03-01

bandwagoning, or neutrality.”14 Roy thinks hedging may or may not involve balancing, as small states seek to maintain more than one strategic option...competitive Sino-US relations, Southeast Asian states have found substantial economic and diplomatic benefits “without over- betting on any options that...navigate between the balancing and bandwagoning spectrum, while maintaining its positive relations with great powers “without over- betting on any

Myopic or Dynamic Liquidity Management? : A Study of Hedge Funds around the 2008 Financial Crisis

NARCIS (Netherlands)

Driessen, Joost; Xing, R.

2017-01-01

In this paper, we show that hedge funds repurchased a large amount of liquid stocks and continued to sell illiquid stocks as the 2008 financial crisis mitigated. It complements existing empirical evidence that institutional investors sold more liquid than illiquid assets during the crisis period.

Optimal Hedge Tracking Portfolios in a Limit Order Book

DEFF Research Database (Denmark)

Ellersgaard, Simon; Tegner, Martin

2017-01-01

-optimizing option seller, who hedges his position using a combination of limit and market orders, while facing certain constraints as to how far he can deviate from a targeted (Bachelierian) delta strategy. By translating the control problem into a three-dimensional Hamilton–Jacobi–Bellman quasi......-variational inequality (HJB QVI) and solving numerically, we are able to deduce optimal limit order quotes alongside the regions surrounding the targeted delta surface in which the option seller must place limit orders vis-à-vis the more aggressive market orders. Our scheme is shown to be monotone, stable......, and consistent and thence, modulo a comparison principle, convergent in the viscosity sense....

Grass leaves as potential hominin dietary resources.

Science.gov (United States)

Paine, Oliver C C; Koppa, Abigale; Henry, Amanda G; Leichliter, Jennifer N; Codron, Daryl; Codron, Jacqueline; Lambert, Joanna E; Sponheimer, Matt

2018-04-01

Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C 4 component in the diets of most taxa, and grass leaves are the single most abundant C 4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource. Copyright © 2017. Published by Elsevier Ltd.

Pricing and Hedging Quanto Options in Energy Markets

DEFF Research Database (Denmark)

Benth, Fred Espen; Lange, Nina; Myklebust, Tor Åge

approach we derive a closed form option pricing formula for energy quanto options, under the assumption that the underlying assets are log-normally distributed. Our approach encompasses several interesting cases, such as geometric Brownian motions and multifactor spot models. We also derive delta and gamma......In energy markets, the use of quanto options have increased significantly in the recent years. The payoff from such options are typically written on an underlying energy index and a measure of temperature and are suited for managing the joint price and volume risk in energy markets. Using an HJM...... expressions for hedging. Furthermore, we illustrate the use of our model by an empirical pricing exercise using NYMEX traded natural gas futures and CME traded Heating Degree Days futures for New York....

Classification of images of wheat, ryegrass and brome grass species at early growth stages using principal component analysis

Directory of Open Access Journals (Sweden)

Golzarian Mahmood R

2011-09-01

Full Text Available Abstract Wheat is one of the most important crops in Australia, and the identification of young plants is an important step towards developing an automated system for monitoring crop establishment and also for differentiating crop from weeds. In this paper, a framework to differentiate early narrow-leaf wheat from two common weeds from their digital images is developed. A combination of colour, texture and shape features is used. These features are reduced to three descriptors using Principal Component Analysis. The three components provide an effective and significant means for distinguishing the three grasses. Further analysis enables threshold levels to be set for the discrimination of the plant species. The PCA model was evaluated on an independent data set of plants and the results show accuracy of 88% and 85% in the differentiation of ryegrass and brome grass from wheat, respectively. The outcomes of this study can be integrated into new knowledge in developing computer vision systems used in automated weed management.

EFFECT OF MULCH AND MIXED CROPPING GRASS - LEGUME AT SALINE SOIL ON GROWTH, FORAGE YIELD AND NUTRITIONAL QUALITY OF GUINEA GRASS

Directory of Open Access Journals (Sweden)

F. Kusmiyati

2014-10-01

Full Text Available The research was conducted to evaluate the effect of mulch and mixed cropping grass – legume atsaline soil on growth, forage yield and nutritional quality of guinea grass. Saline soil used in thisresearch was classified into strongly saline soil with low soil fertility. The research was arrranged inrandomized complete block design with 3 blocks. The treatments were : M1 = guinea grassmonoculture, without mulch; M2 = guinea grass monoculture, 3 ton/ha mulch; M3 = guinea grassmonoculture, 6 ton/ha mulch, M4 = mixed cropping grass with Sesbania grandiflora, without mulch;M5 = mixed cropping grass with Sesbania grandiflora, 3 ton/ha mulch; M6 = mixed cropping grass withSesbania grandiflora, 6 ton/ha mulch. Data were analyzed using analysis of variance, then followed byDuncan's Multiple Range Test. The highest soil moisture content was achieved at mixed cropping grasslegumewith 6 ton/ha of mulch. The effect of mulch at saline soil significantly increased plant growth,forage yield and nutritional quality of guinea grass. Application of 3 ton/ha mulch increased plantgrowth, forage yield and nutritional quality of guinea grass. Plant growth, forage yield and nutritionalquality of guinea grass were not affected by monoculture or mixed cropping with Sesbania at saline soil.

Evaluating grasses as a long-term energy resource

Energy Technology Data Exchange (ETDEWEB)

Christian, D.G.; Riche, A.B.

2001-07-01

The work reported here is part of an ongoing project that aims to evaluate the yields of three perennial rhizomatous grasses and determine their suitability as bio-energy crops. The work began in 1993, and the grasses have been monitored continuously since that time. This report covers the period 1999/2000, and includes: the performance of plots of the energy grasses Miscanthus grass, switchgrass and reed canary grass seven years after they were planted; assessment of the yield of 15 genotypes of Miscanthus planted in 1997; monitoring all the species throughout the growing period for the presence of pests, weeds and diseases; measurement of the amount of nitrate leached from below Miscanthus grass; investigating the occurrence of lodging in switchgrass. (Author)

The Impact of Portfolio Disclosure on Hedge Fund Performance, Fees and Flows

OpenAIRE

Zhen Shi

2011-01-01

This study investigates the impact of portfolio disclosure on hedge fund performance. Using a regression discontinuity design, I investigate the effect of the disclosure requirements that take effect when an investment company's assets exceed $100 million; when that occurs, a fund is required by the U.S. Securities and Exchange Commission to submit form 13F disclosing its portfolio holdings. Consistent with the argument that portfolio disclosure reveals 'trade secrets' and also raises front r...

Risks in global natural gas markets: Investment, hedging and trade

International Nuclear Information System (INIS)

Egging, Ruud; Holz, Franziska

2016-01-01

Recent supply security concerns in Europe have revived interest into the natural gas market. We investigate infrastructure investment and trade in an imperfect market structure for various possible risks for both supply and demand. We focus on three possible scenarios in a stochastic global gas market model: (i) transit of Russian gas via Ukraine that may be disrupted from 2020 on; (ii) natural gas intensity of electricity generation in OECD countries that may lead to higher or lower natural gas demand after 2025; and (iii) availability of shale gas around the globe after 2030. We illustrate how the timing of investments is affected by inter-temporal hedging behavior of market agents, such as when LNG capacity provides ex-ante flexibility or an ex-post fallback option if domestic or nearby pipeline supply sources are low. Moreover, we find that investment in LNG capacities is more determined by demand side pull – due to higher needs in electric power generation – than by supply side push, e.g. higher shale gas supplies needing an outlet. We focus on Europe, North America, and China that are the world's most important gas consuming and supplying regions. - Highlights: •We use the stochastic variant of the multi-period Global Gas Model. •We investigate the effects of uncertainty in Russian exports, demand, and shale gas. •We find that LNG is preferred as hedging option in anticipation of uncertain events. •Pipelines may be chosen as recourse decision after uncertain events realized. •China will dominate the global natural gas market regardless the scenario.

The Effect of Founder Family Influence on Hedging and Speculation

DEFF Research Database (Denmark)

Aabo, Tom; Kuhn, Jochen; Zanotti, Giovanna

We investigate the effect of founder family influence in the form of managers, board of directors, and/or ownership on hedging and speculation in medium-sized, manufacturing firms in Denmark. On a crude measure of use / non-use of derivatives we find only a weak indication of differences between...... founder family firms and other firms in relation to their management of foreign exchange rate, interest rate, and commodity price exposures. Digging deeper into a subsample of users of foreign exchange derivatives and debt denominated in foreign currency, we find that founder family firms not only tend...

Genetic compatibility determines endophyte-grass combinations.

Directory of Open Access Journals (Sweden)

Kari Saikkonen

Full Text Available Even highly mutually beneficial microbial-plant interactions, such as mycorrhizal- and rhizobial-plant exchanges, involve selfishness, cheating and power-struggles between the partners, which depending on prevailing selective pressures, lead to a continuum of interactions from antagonistic to mutualistic. Using manipulated grass-endophyte combinations in a five year common garden experiment, we show that grass genotypes and genetic mismatches constrain genetic combinations between the vertically (via host seeds transmitted endophytes and the out-crossing host, thereby reducing infections in established grass populations. Infections were lost in both grass tillers and seedlings in F(1 and F(2 generations, respectively. Experimental plants were collected as seeds from two different environments, i.e., meadows and nearby riverbanks. Endophyte-related benefits to the host included an increased number of inflorescences, but only in meadow plants and not until the last growing season of the experiment. Our results illustrate the importance of genetic host specificity and trans-generational maternal effects on the genetic structure of a host population, which act as destabilizing forces in endophyte-grass symbioses. We propose that (1 genetic mismatches may act as a buffering mechanism against highly competitive endophyte-grass genotype combinations threatening the biodiversity of grassland communities and (2 these mismatches should be acknowledged, particularly in breeding programmes aimed at harnessing systemic and heritable endophytes to improve the agriculturally valuable characteristics of cultivars.

Preliminary Results of Clover and Grass Coverage and Total Dry Matter Estimation in Clover-Grass Crops Using Image Analysis

Directory of Open Access Journals (Sweden)

Anders K. Mortensen

2017-12-01

Full Text Available The clover-grass ratio is an important factor in composing feed ratios for livestock. Cameras in the field allow the user to estimate the clover-grass ratio using image analysis; however, current methods assume the total dry matter is known. This paper presents the preliminary results of an image analysis method for non-destructively estimating the total dry matter of clover-grass. The presented method includes three steps: (1 classification of image illumination using a histogram of the difference in excess green and excess red; (2 segmentation of clover and grass using edge detection and morphology; and (3 estimation of total dry matter using grass coverage derived from the segmentation and climate parameters. The method was developed and evaluated on images captured in a clover-grass plot experiment during the spring growing season. The preliminary results are promising and show a high correlation between the image-based total dry matter estimate and the harvested dry matter ( R 2 = 0.93 with an RMSE of 210 kg ha − 1 .

Sellers' hedging incentives at EPA's emission trading auction

International Nuclear Information System (INIS)

Dijkstra, B.R.; Haan, M

1999-01-01

Cason (1993) argued that the auction the EPA (Environmental Protection Agency in the USA) used in order to start the market for sulfur allowances, is not efficient. The set-up of the auction gives both buyers and sellers an incentive to understate their valuation of an allowance. In this paper, we show that the sellers' incentives are even more perverse than Cason suggested. In particular, we show that sellers have an incentive to set their ask price equal to zero, while simultaneously hedging their bets by submitting a positive bid. It is not possible to derive the Nash equilibrium for this set-up. If such an equilibrium exists, sellers either set only a positive ask price, or an ask price equal to zero, and a positive bid as well. 14 refs

Pricing and Hedging Quanto Options in Energy Markets

DEFF Research Database (Denmark)

Benth, Fred Espen; Lange, Nina; Myklebust, Tor Åge

2015-01-01

–Jarrow–Morton approach, we derive a closed-form option pricing formula for energy quanto options under the assumption that the underlying assets are lognormally distributed. Our approach encompasses several interesting cases, such as geometric Brownian motions and multifactor spot models. We also derive Delta and Gamma......In energy markets, the use of quanto options has increased significantly in recent years. The payoff from such options are typically written on an underlying energy index and a measure of temperature. They are suited to managing the joint price and volume risk in energy markets. Using a Heath...... expressions for hedging. Further, we illustrate the use of our model by an empirical pricing exercise using NewYork Mercantile Exchange-traded natural gas futures and Chicago Mercantile Exchange-traded heating degree days futures for NewYork....

The Dirichlet Portfolio Model: Uncovering the Hidden Composition of Hedge Fund Investments

OpenAIRE

Korsos, Laszlo F.

2013-01-01

Hedge funds have long been viewed as a veritable "black box" of investing since outsiders may never view the exact composition of portfolio holdings. Therefore, the ability to estimate an informative set of asset weights is highly desirable for analysis. We present a compositional state space model for estimation of an investment portfolio's unobserved asset allocation weightings on a set of candidate assets when the only observed information is the time series of portfolio returns and the ca...

The role of non-genetic inheritance in evolutionary rescue: epigenetic buffering, heritable bet hedging and epigenetic traps.

Science.gov (United States)

O'Dea, Rose E; Noble, Daniel W A; Johnson, Sheri L; Hesselson, Daniel; Nakagawa, Shinichi

2016-01-01

Rapid environmental change is predicted to compromise population survival, and the resulting strong selective pressure can erode genetic variation, making evolutionary rescue unlikely. Non-genetic inheritance may provide a solution to this problem and help explain the current lack of fit between purely genetic evolutionary models and empirical data. We hypothesize that epigenetic modifications can facilitate evolutionary rescue through 'epigenetic buffering'. By facilitating the inheritance of novel phenotypic variants that are generated by environmental change-a strategy we call 'heritable bet hedging'-epigenetic modifications could maintain and increase the evolutionary potential of a population. This process may facilitate genetic adaptation by preserving existing genetic variation, releasing cryptic genetic variation and/or facilitating mutations in functional loci. Although we show that examples of non-genetic inheritance are often maladaptive in the short term, accounting for phenotypic variance and non-adaptive plasticity may reveal important evolutionary implications over longer time scales. We also discuss the possibility that maladaptive epigenetic responses may be due to 'epigenetic traps', whereby evolutionarily novel factors (e.g. endocrine disruptors) hack into the existing epigenetic machinery. We stress that more ecologically relevant work on transgenerational epigenetic inheritance is required. Researchers conducting studies on transgenerational environmental effects should report measures of phenotypic variance, so that the possibility of both bet hedging and heritable bet hedging can be assessed. Future empirical and theoretical work is required to assess the relative importance of genetic and epigenetic variation, and their interaction, for evolutionary rescue.

Using electricity options to hedge against financial risks of power producers

DEFF Research Database (Denmark)

Pineda Morente, Salvador; Conejo, Antonio J.

2013-01-01

or unexpected unit failures faced by power producers. A multi-stage stochastic model is described in this tutorial paper to determine the optimal forward and option contracting decisions for a risk-averse power producer. The key features of electricity options to reduce both price and availability risks......As a consequence of competition in electricity markets, a wide variety of financial derivatives have emerged to allow market agents to hedge against risks. Electricity options and forward contracts constitute adequate instruments to manage the financial risks pertaining to price volatility...

Grass Biomethane for Agriculture and Energy

DEFF Research Database (Denmark)

Korres, N.E.; Thamsiriroj, T.; Smith, B.

2011-01-01

have advanced the role of grassland as a renewable source of energy in grass biomethane production with various environmental and socio-economic benefits. It is underlined that the essential question whether the gaseous biofuel meets the EU sustainability criteria of 60% greenhouse gas emission savings...... by 2020 can be met since savings up to 89.4% under various scenarios can be achieved. Grass biomethane production compared to other liquid biofuels either when these are produced by indigenous of imported feedstocks is very promising. Grass biomethane, given the mature and well known technology...

Integrated Strategic Planning of Global Production Networks and Financial Hedging under Uncertain Demands and Exchange Rates

Directory of Open Access Journals (Sweden)

Achim Koberstein

2013-11-01

Full Text Available In this paper, we present a multi-stage stochastic programming model that integrates financial hedging decisions into the planning of strategic production networks under uncertain exchange rates and product demands. This model considers the expenses of production plants and the revenues of markets in different currency areas. Financial portfolio planning decisions for two types of financial instruments, forward contracts and options, are represented explicitly by multi-period decision variables and a multi-stage scenario tree. Using an illustrative example, we analyze the impact of exchange-rate and demand volatility, the level of investment expenses and interest rate spreads on capacity location and dimensioning decisions. In particular, we show that, in the illustrative example, the exchange-rate uncertainty cannot be completely eliminated by financial hedging in the presence of demand uncertainty. In this situation, we find that the integrated model can result in better strategic planning decisions for a risk-averse decision maker compared to traditional modeling approaches.

A administração do lucro contábil e os critérios para determinação da eficácia do hedge accounting: utilização da correlação simples dentro do arcabouço do sfas nº 133

Directory of Open Access Journals (Sweden)

Alexsandro Broedel Lopes

2003-04-01

Full Text Available O hedge accounting constitui inovação relevante introduzida pelo SFAS 133. Dentro desse critério, operações designadas como hedge deverão ter seus resultados diferidos para o momento no qual os itens sendo protegidos forem reconhecidos. Problema central nessa contabilização é a determinação do quê constitui uma operação de hedge. Os órgãos reguladores analisados neste trabalho apresentam critérios ad hoc para a determinação da eficácia das operações de hedge. Esses critérios não possuem propriedades estatísticas de previsão do comportamento dos ativos no futuro, condição necessária para o sucesso do hedge. Esse tipo de qualificação de hedge introduz enorme subjetividade no processo de reconhecimento contábil, fornecendo ampla margem para manipulação dos resultados. Este trabalho analisa e critica a opção adotada pelo FASB e outros órgãos reguladores e oferece sugestões.The hedge accounting mechanism is a recent innovation introduced by SFAS 133. According to this method, transactions designated as hedge should have their results deferred to a future period when the hedged items are recognised. hedge characterisation is a central problem in this subject. Regulatory bodies studied in this work use ad hoc criteria to determine hedge effectiveness. Those criteria are not statistically significant in terms of forecasting the asset's behaviour, a necessary condition for a successful hedge. This sort of hedge characterisation introduces more subjectivity into accounting recognition, allowing for manipulation. This work criticises the option adopted by FASB and other regulatory bodies.

Determining the regional potential for a grass biomethane industry

International Nuclear Information System (INIS)

Smyth, Beatrice M.; Smyth, Henry; Murphy, Jerry D.

2011-01-01

Research highlights: → We identified assessment criteria for determining the regional potential for grass biomethane. → Grass biomethane is distributed via the natural gas grid. → The criteria include: land use; grass yields; gas grid coverage; availability of co-substrates. → The county with the highest potential can fuel 50% of cars or supply 130% of domestic gas consumption. - Abstract: Grass biogas/biomethane has been put forward as a renewable energy solution and it has been shown to perform well in terms of energy balance, greenhouse gas emissions and policy constraints. Biofuel and energy crop solutions are country-specific and grass biomethane has strong potential in countries with temperate climates and a high proportion of grassland, such as Ireland. For a grass biomethane industry to develop in a country, suitable regions (i.e. those with the highest potential) must be identified. In this paper, factors specifically related to the assessment of the potential of a grass biogas/biomethane industry are identified and analysed. The potential for grass biogas and grass biomethane is determined on a county-by-county basis using multi-criteria decision analysis. Values are assigned to each county and ratings and weightings applied to determine the overall county potential. The potential for grass biomethane with co-digestion of slaughter waste (belly grass) is also determined. The county with the highest potential (Limerick) is analysed in detail and is shown to have ready potential for production of gaseous biofuel to meet either 50% of the vehicle fleet or 130% of the domestic natural gas demand, through 25 facilities at a scale of ca. 30 kt yr -1 of feedstock. The assessment factors developed in this paper can be used in other resource studies into grass biomethane or other energy crops.

Post-treatment efficacy of discontinuous treatment with 300IR 5-grass pollen sublingual tablet in adults with grass pollen-induced allergic rhinoconjunctivitis

DEFF Research Database (Denmark)

Didier, A; Malling, H-J; Worm, Marcel

2013-01-01

Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis.......Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis....

Gold as an Infl ation Hedge in a Time-Varying Coefficient Framework

OpenAIRE

Beckmann, Joscha; Czudaj, Robert

2012-01-01

This study analyzes the question whether gold provides the ability of hedging against inflation from a new perspective. Using data for four major economies, namely the USA, the UK, the Euro Area, and Japan, we allow for nonlinearity and discriminate between long-run and time-varying short-run dynamics. Thus, we conduct a Markov-switching vector error correction model (MS-VECM) approach for a sample period ranging from January 1970 to December 2011. Our main findings are threefold: First, we s...

Temporal variability and cooperative breeding: testing the bet-hedging hypothesis in the acorn woodpecker.

Science.gov (United States)

Koenig, Walter D; Walters, Eric L

2015-10-07

Cooperative breeding is generally considered an adaptation to ecological constraints on dispersal and independent breeding, usually due to limited breeding opportunities. Although benefits of cooperative breeding are typically thought of in terms of increased mean reproductive success, it has recently been proposed that this phenomenon may be a bet-hedging strategy that reduces variance in reproductive success (fecundity variance) in populations living in highly variable environments. We tested this hypothesis using long-term data on the polygynandrous acorn woodpecker (Melanerpes formicivorus). In general, fecundity variance decreased with increasing sociality, at least when controlling for annual variation in ecological conditions. Nonetheless, decreased fecundity variance was insufficient to compensate for reduced per capita reproductive success of larger, more social groups, which typically suffered lower estimated mean fitness. We did, however, find evidence that sociality in the form of larger group size resulted in increased fitness in years following a small acorn crop due to reduced fecundity variance. Bet-hedging, although not the factor driving sociality in general, may play a role in driving acorn woodpecker group living when acorns are scarce and ecological conditions are poor. © 2015 The Author(s).

Grasses for energy production: hydrological guidelines

Energy Technology Data Exchange (ETDEWEB)

Hall, R.L.

2003-07-01

This report provides hydrological guidelines for growers, land and water resource managers, environmental groups and other parties interested in utilising grasses for energy production. The aim of the report is to help interested parties decide if a location is suitable for planting energy grasses by considering whether potential hydrological impacts will have an adverse effect on crop productivity and yield. The guidelines consider: the water use of energy grasses compared with other crops; the factors governing water use; the water requirements for a productive crop; and the likely impacts on the availability and quantity of water. The report points out that there are still gaps in our knowledge of the processes controlling the water use and growth of energy grasses and notes that, in some situations, there will be considerable uncertainty in predictions of water use and the magnitude of the associated hydrological impacts.

Hedging LDC price risk in the futures market

International Nuclear Information System (INIS)

Trace, J.W.

1990-01-01

During its first five months the natural gas futures market has seen steady growth and increasing participation by various industry players, particularly producers, marketers, and brokers. Not much has been heard, however, about participation by the principal retailers of the gas industry, the local distribution companies (LDCs). Undoubtedly, various LDCs are now in the process of determining whether or not the gas futures market can serve any useful business purpose in their operations. In examining this question LDCs should keep in mind that the futures market should serve the same purpose for them as it does for any other business engaged in the actual buying and selling of price-volatile commodities - mitigation of price risk. This article looks at the risks of the market, gives examples of investments to hedge risks and looks at the overall performance of the market

The Buyers’ Perspective on Security Design: Hedge Funds and Convertible Bond Call Provisions

OpenAIRE

Grundy, Bruce; Verwijmeren, Patrick

2016-01-01

textabstractWe provide evidence that security design reflects the interplay of capital supplier and security issuer preferences. While call provisions have historically been the default option in convertible security design, only a minority of post-2005 issues are callable. Because hedge funds dominate the market for new convertibles today and because convertible arbitrage is less risky without callability, the recent diminution in the frequency of call provisions in new convertible bond issu...

The buyers’ perspective on security design: Hedge funds and convertible bond call provisions

OpenAIRE

Grundy, Bruce D.; Verwijmeren, Patrick

2018-01-01

We provide evidence that security design reflects the interplay of capital supplier and security issuer preferences. While call provisions have historically been the default option in convertible security design, only a minority of post-2005 issues are callable. Because hedge funds dominate the market for new convertibles today and because convertible arbitrage is less risky without callability, the recent diminution in the frequency of call provisions in new convertible bond issues illustrat...

Longevity Risk and Natural Hedge Potential in Portfolios Of Life Insurance Products : The Effect of Investment Risk

NARCIS (Netherlands)

Stevens, R.S.P.; De Waegenaere, A.M.B.; Melenberg, B.

2011-01-01

Payments of life insurance products depend on the uncertain future evolution of survival probabilities. This uncertainty is referred to as longevity risk. Existing literature shows that the effect of longevity risk on single life annuities can be substantial, and that there exists a (natural) hedge

Weather derivatives or how an energy company can hedge its weather risks

International Nuclear Information System (INIS)

Tahghighi, A.; Carpentier, Ph.

2000-01-01

This paper gives a detailed overview of weather derivatives and explains where this new class of financial products falls. The emergence of weather derivatives came about as a response to a need in the energy sector to hedge this sector's weather risks. This article focuses on the nature of these financial contracts, what they include and how they are priced. This article concludes by stating that energy companies in Europe can no longer afford to remain exposed to weather risks in an increasingly privatized and competitive market

Derivatives Usage by Non-Financial Firms in Thailand; implications on the hedging strategy

OpenAIRE

Chawla, Veerathep

2007-01-01

This dissertation is the result of the research carried out to investigate the derivatives usage in 65 non-financial companies across 8 specified industries in Thailand. The use of derivatives in Thailand is growing rapidly every year, our survey shows 75% of firms using derivatives in their hedging strategy. There is no significance in the use between Thai and Foreign companies in Thailand, while smaller firms do not use derivatives as much as larger firms, especially large listed companies....

(IAM Series No 005) Are “Market Neutral” Hedge Funds Really Market Neutral?

OpenAIRE

Andrew Patton

2004-01-01

One can consider the concept of market neutrality for hedge funds as having breadth and depth: breadth reflects the number of market risks to which a fund is neutral, while depth reflects the completeness of the neutrality of the fund to market risks. We focus on market neutrality depth, and propose five different neutrality concepts. Mean neutrality nests the standard correlation-based definition of neutrality. Variance neutrality, Value-at-Risk neutrality and tail neutrality all relate to t...

VAM populations in relation to grass invasion associated with forest decline.

Science.gov (United States)

Vosatka, M; Cudlin, P; Mejstrik, V

1991-01-01

Spruce stands in Northern Bohemia forests, damaged to various degrees by industrial pollution, have shown establishment of grass cover following tree defoliation. Populations of vesicular-arbuscular mycorrhizal (VAM) fungi were studied under this grass cover in four permanent plots with spruce under different levels of pollution stress. Soil and root samples were collected in April and June within each plot as follows: (1) sites without grass, (2) sites with initial stages of grass invasion, and (3) sites with fully developed grass cover. In all plots, the highest number of propagules were recovered from samples taken from sites having full grass cover. Mycorrhizal infection of grass was highest in the plot with the severest pollution damage and lowest in the least damaged plot. The development of grass cover and VAM infection of grass increased with tree defoliation caused by air pollution.

Grass survey of the Itremo Massif records endemic central highland ...

African Journals Online (AJOL)

Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses.

Hedging Price Risks of Farmers by Commodity Boards: A Simulation Applied to the Indian Natural Rubber Market

NARCIS (Netherlands)

Zant, W.

2001-01-01

This paper investigates a hypothetical hedging scheme in a domestic commodity market under which a commodity board offers a forward contract to domestic producers and local traders and covers its commitments on an international futures exchange. It is aimed to quantify welfare gains to agents in the

Rumen escape protein in grass and grass silage deterimened with a nylon bag and an enzymatic technique

NARCIS (Netherlands)

Cone, J.W.; Gelder, van A.H.; Mathijssen-Kamman, A.A.; Hindle, V.A.

2004-01-01

Rumen escape protein (REP) was determined for six grasses and 16 grass silages using a nylon bag technique and an in vitro technique using a proteolytic enzyme preparation of Streptomyces griseus. In vitro, the samples were incubated for 0, 1, 6 and 24 h. The highest correlation observed between

EroGRASS : Failure of grass cover layers at seaward and shoreward dike slopes. design, construction and performance

NARCIS (Netherlands)

Verhagen, H.J.; Verheij, H.J.; Cao, T.M.; Dassanayake, D.; Roelvink, D.; Piontkowitz, T.

2009-01-01

A large number of the dikes in the North Sea and Baltic Sea regions are covered with grass that is exposed to hydraulic loading from waves and currents during storm surges. During previous storm surges the grass cover layers often showed large strength and remained undamaged. A clear physical

Investigation of Desso GrassMaster® as application in hydraulic engineering

NARCIS (Netherlands)

Steeg, van der P.; Paulissen, M.P.C.P.; Roex, E.; Mommer, L.

2015-01-01

Dessa GrassMaster® is a reinforced grass system which is applied successfully on sports fields and enables to use a sports field more intensively than a normal grass field. In this report the possibility of an application of Dessa GrassMaster®in hydraulic conditions, with a focus on grass dikes, is

Established native perennial grasses out-compete an invasive annual grass regardless of soil water and nutrient availability

Science.gov (United States)

Christopher M. McGlone; Carolyn Hull Sieg; Thomas E. Kolb; Ty Nietupsky

2012-01-01

Competition and resource availability influence invasions into native perennial grasslands by nonnative annual grasses such as Bromus tectorum. In two greenhouse experiments we examined the influence of competition, water availability, and elevated nitrogen (N) and phosphorus (P) availability on growth and reproduction of the invasive annual grass B. tectorum and two...

Germination of Themeda triandra (Kangaroo grass) as affected by ...

African Journals Online (AJOL)

Low rainfall in range areas restricts germination, growth and development of majority of range grasses. However, germination and establishment potential of forage grasses vary and depends on environmental conditions. Themeda triandra is an excellent known grass to grow under different environmental conditions.

The importance of cross-reactivity in grass pollen allergy

Directory of Open Access Journals (Sweden)

Aleksić Ivana

2014-01-01

Full Text Available According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions. [Projekat Ministarstva nauke Republike Srbije, br. 172049 i br. 172024

Thermogravimetric analysis of forest understory grasses

Science.gov (United States)

Thomas Elder; John S. Kush; Sharon M. Hermann

2011-01-01

Forest understory grasses are of significance in the initiation, establishment and maintenance of fire, whether used as a management tool or when occurring as wildfire. The fundamental thermal properties of such grasses are critical to their behavior in fire situations and have been investigated in the current work by the application of thermogravimetric analysis (TGA...

Names of Southern African grasses: Name changes and additional ...

African Journals Online (AJOL)

The main reasons for changes in botanical names are briefly reviewed, with examples from the lists. At this time, about 1040 grass species and subspecific taxa are recognized in the subcontinent. Keywords: botanical research; botanical research institute; botany; grass; grasses; identification; name change; nomenclature; ...

Bayesian Nonparametric Measurement of Factor Betas and Clustering with Application to Hedge Fund Returns

Directory of Open Access Journals (Sweden)

Urbi Garay

2016-03-01

Full Text Available We define a dynamic and self-adjusting mixture of Gaussian Graphical Models to cluster financial returns, and provide a new method for extraction of nonparametric estimates of dynamic alphas (excess return and betas (to a choice set of explanatory factors in a multivariate setting. This approach, as well as the outputs, has a dynamic, nonstationary and nonparametric form, which circumvents the problem of model risk and parametric assumptions that the Kalman filter and other widely used approaches rely on. The by-product of clusters, used for shrinkage and information borrowing, can be of use to determine relationships around specific events. This approach exhibits a smaller Root Mean Squared Error than traditionally used benchmarks in financial settings, which we illustrate through simulation. As an illustration, we use hedge fund index data, and find that our estimated alphas are, on average, 0.13% per month higher (1.6% per year than alphas estimated through Ordinary Least Squares. The approach exhibits fast adaptation to abrupt changes in the parameters, as seen in our estimated alphas and betas, which exhibit high volatility, especially in periods which can be identified as times of stressful market events, a reflection of the dynamic positioning of hedge fund portfolio managers.

Gold as an Infl ation Hedge in a Time-Varying Coeffi cient Framework

OpenAIRE

Joscha Beckmann; Robert Czudaj

2012-01-01

This study analyzes the question whether gold provides the ability of hedging against inflation from a new perspective. Using data for four major economies, namely the USA, the UK, the Euro Area, and Japan, we allow for nonlinearity and discriminate between long-run and time-varying short-run dynamics. Thus, we conduct a Markov-switching vector error correction model (MS-VECM) approach for a sample period ranging from January 1970 to December 2011. Our main findings are threefold: First, we s...

Hedge Accounting in the Brazilian Stock Market: Effects on the Quality of Accounting Information, Disclosure, and Information Asymmetry

Directory of Open Access Journals (Sweden)

Silas Adolfo Potin

2016-08-01

Full Text Available ABSTRACT This paper investigates, in the Brazilian stock market, the effect of hedge accounting on the quality of financial information, on the disclosure of derivative financial instruments, and on the information asymmetry. To measure the quality of accounting information, relevance metrics of accounting information and book earnings informativeness were used. For executing this research, a general sample was obtained through Brazilian companies, non-financial, listed on the Brazilian Securities, Commodities, and Futures Exchange (BM&FBOVESPA, comprising the 150 companies with highest market value on 01/01/2014. Through the general sample, samples were compiled for applying the econometric models of value relevance, informativeness, disclosure, and information asymmetry. The sample for relevance had 758 companies-years observations within the period from 2008 to 2013; the sample for informativeness had 701 companies-years observations with the period from 2008 to 2013; the sample for disclosure had 100 companies-years observations, within the period from 2011 to 2012; the sample for information asymmetry had 100 companies-years observations, also related to the period from 2011 to 2012. In addition to the econometric models, the propensity score matching method was applied to the analyses of the hedge accounting effect on disclosure and information asymmetry. The evidence found for the influence of hedge accounting indicates a relation: (i positive and significant concerning accounting information relevance and disclosure of derivatives; (ii negative and significant for book earnings informativeness. Regarding information asymmetry, although the coefficients showed up as expected, they were not statistically significant.

Bud-bank and tiller dynamics of co-occurring C3 caespitose grasses in mixed-grass prairie.

Science.gov (United States)

Ott, Jacqueline P; Hartnett, David C

2015-09-01

Tiller recruitment from the belowground bud bank of caespitose grasses influences their ability to monopolize local resources and, hence, their genet fitness. Differences in bud production and outgrowth among tiller types within a genet and among species may explain co-occurrence of caespitose grasses. This study aimed to characterize genet bud-bank and tiller production and dynamics in two co-occurring species and compare their vegetative reproductive strategies. Bud-bank and tiller dynamics of Hesperostipa comata and Nassella viridula, dominant C3 caespitose grasses in the northern mixed-grass prairie of North America, were assessed throughout an annual cycle. The two species showed similar strategies, maintaining polycyclic tillers and thus creating mixed-age genet bud banks comprising multiple bud cohorts produced in different years. Vegetative tillers produced the majority of buds, whereas flowering tillers contributed little to the bud bank. Buds lived for at least 2 yr and were maintained in multiple developmental stages throughout the year. Because bud longevity rarely exceeded tiller longevity, tiller longevity drove turnover within the bud bank. Tiller population dynamics, more than bud production per tiller, determined the differential contribution of tiller types to the bud bank. Nassella viridula had higher bud production per tiller, a consistent annual tiller recruitment density, and greater longevity of buds on senesced and flowering tillers than H. comata. Co-occurring C3 caespitose grasses had similar bud-bank and tiller dynamics contributing to genet persistence but differed in bud characteristics that could affect genet longevity and species coexistence. © 2015 Botanical Society of America.

Using financial derivatives to hedge against currency risk : British large and medium-sized firms

OpenAIRE

Nguyen, My

2012-01-01

Nowadays, as a growing number of firms strive to conduct their business at international market place, currency risk has increasingly raised concern among financial mangers due to its substantial impact on companies’ financial results. Financial derivative instruments (Forward, Futures, Options, Swaps) are utilized as efficient hedging mechanisms against such an exchange rate exposure. The main objective of this study is to examine whether derivatives play a primary role in mitigating an adve...

Rhetorical Impact through Hedging Devices in the "Results and Discussion" Part of a Civil Engineering Research Article

Science.gov (United States)

Khamesian, Minoo

2015-01-01

It is common knowledge that hedging devices as a rhetorical technique common in all persuasive writing are considerably important in scientific discourse, for they are tools which facilitate presenting claims or arguments in a polite, acceptable and respectful manner. In addition, they are discoursal resources available to a scientific writer's…

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

Science.gov (United States)

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

2017-11-01

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

GRASS GIS: The first Open Source Temporal GIS

Science.gov (United States)

Gebbert, Sören; Leppelt, Thomas

2015-04-01

GRASS GIS is a full featured, general purpose Open Source geographic information system (GIS) with raster, 3D raster and vector processing support[1]. Recently, time was introduced as a new dimension that transformed GRASS GIS into the first Open Source temporal GIS with comprehensive spatio-temporal analysis, processing and visualization capabilities[2]. New spatio-temporal data types were introduced in GRASS GIS version 7, to manage raster, 3D raster and vector time series. These new data types are called space time datasets. They are designed to efficiently handle hundreds of thousands of time stamped raster, 3D raster and vector map layers of any size. Time stamps can be defined as time intervals or time instances in Gregorian calendar time or relative time. Space time datasets are simplifying the processing and analysis of large time series in GRASS GIS, since these new data types are used as input and output parameter in temporal modules. The handling of space time datasets is therefore equal to the handling of raster, 3D raster and vector map layers in GRASS GIS. A new dedicated Python library, the GRASS GIS Temporal Framework, was designed to implement the spatio-temporal data types and their management. The framework provides the functionality to efficiently handle hundreds of thousands of time stamped map layers and their spatio-temporal topological relations. The framework supports reasoning based on the temporal granularity of space time datasets as well as their temporal topology. It was designed in conjunction with the PyGRASS [3] library to support parallel processing of large datasets, that has a long tradition in GRASS GIS [4,5]. We will present a subset of more than 40 temporal modules that were implemented based on the GRASS GIS Temporal Framework, PyGRASS and the GRASS GIS Python scripting library. These modules provide a comprehensive temporal GIS tool set. The functionality range from space time dataset and time stamped map layer management

MACRO NUTRIENTS UPTAKE OF FORAGE GRASSES AT DIFFERENT SALINITY STRESSES

Directory of Open Access Journals (Sweden)

F. Kusmiyati

2014-10-01

Full Text Available The high concentration of sodium chloride (NaCl in saline soils has negative effects on the growth ofmost plants. The experiment was designed to evaluate macro nutrient uptake (Nitrogen, Phosphorus andPotassium of forage grasses at different NaCl concentrations in growth media. The experiment wasconducted in a greenhouse at Forage Crops Laboratory of Animal Agriculture Faculty, Diponegoro University.Split plot design was used to arrange the experiment. The main plot was forage grasses (Elephant grass(Pennisetum purpureum and King grass (Pennisetum hybrida. The sub plot was NaCl concentrationin growth media (0, 150, and 300 mM. The nitrogen (N, phosphorus (P and potassium (K uptake in shootand root of plant were measured. The result indicated increasing NaCl concentration in growth mediasignificantly decreased the N, P and K uptake in root and shoot of the elephant grass and king grass. Thepercentage reduction percentage of N, P and K uptake at 150 mM and 300 mM were high in elephant grassand king grass. It can be concluded that based on nitrogen, phosphorus and potassium uptake, elephantgrass and king grass are not tolerant to strong and very strong saline soil.

Grasses as invasive plants in South Africa revisited: Patterns, pathways and management

Directory of Open Access Journals (Sweden)

Vernon Visser

2017-03-01

Full Text Available Background: In many countries around the world, the most damaging invasive plant species are grasses. However, the status of grass invasions in South Africa has not been documented recently. Objectives: To update Sue Milton’s 2004 review of grasses as invasive alien plants in South Africa, provide the first detailed species level inventory of alien grasses in South Africa and assess the invasion dynamics and management of the group. Method: We compiled the most comprehensive inventory of alien grasses in South Africa to date using recorded occurrences of alien grasses in the country from various literature and database sources. Using historical literature, we reviewed past efforts to introduce alien grasses into South Africa. We sourced information on the origins, uses, distributions and minimum residence times to investigate pathways and patterns of spatial extent. We identified alien grasses in South Africa that are having environmental and economic impacts and determined whether management options have been identified, and legislation created, for these species. Results: There are at least 256 alien grass species in the country, 37 of which have become invasive. Alien grass species richness increased most dramatically from the late 1800s to about 1940. Alien grass species that are not naturalised or invasive have much shorter residence times than those that have naturalised or become invasive. Most grasses were probably introduced for forage purposes, and a large number of alien grass species were trialled at pasture research stations. A large number of alien grass species in South Africa are of Eurasian origin, although more recent introductions include species from elsewhere in Africa and from Australasia. Alien grasses are most prevalent in the south-west of the country, and the Fynbos Biome has the most alien grasses and the most widespread species. We identified 11 species that have recorded environmental and economic impacts in the

Severity of scab and its effects on fruit weight in mechanically hedge-pruned and topped pecan trees

Science.gov (United States)

Scab is the most damaging disease of pecan in the southeastern USA. Pecan trees can attain 44 m in height, so managing disease in the upper canopy is a problem. Fungicide is ordinarily applied using ground-based air-blast sprayers. Although mechanical hedge-pruning and topping of pecan is done for s...

Lessons learned in managing alfalfa-grass mixtures

Science.gov (United States)

Grass-alfalfa mixtures have a number of benefits that make them attractive to producers. However, they can be problematic to establish and maintain. Research programs have made progress in understanding the benefits and challenges of alfalfa-grass mixtures. Mixtures may have greater winter survival ...

Variation in important pasture grasses: I. Morphological and ...

African Journals Online (AJOL)

Variation in important pasture grasses: I. Morphological and geographical variation. ... Seven species are important pasture grasses throughout the western Transvaal, Orange Free State, northern Cape and Natal. ... Language: English.

Mass variation effect of teki grass (cyperus rotundus) composite against tensile strength and density

Science.gov (United States)

Rafiq Yanhar, Muhammad; Haris Nasution, A.

2018-05-01

The primary purpose of this study is to determine the tensile strength using ASTM D638 - 02a type IVB and density of teki grass (Cyperus rotundus) composite. The production process is carried out by mass variation of 2 gr, 3 gr, and 4 gr. Hand lay-up method with three repetitions is applied. Teki grass is chosen because it is easy to find and has some advantages biodegradable, harmless to health, available in large quantities, and cost-efficient. The test result showed the largest tensile strength is 21,61 MPa at 2-gram mass fiber. Fiber addition to 3 gram and 4-gram cause tensile strength decreases to 18,51 MPa and 11,65 MPa. It happens because the fibers are random and spread in all directions, so many fibers are undirectional with the tensile force. Beside that fibers addition made matrix volume reduced and a bond between fiber and matrix decreases, finally make fiber unable to hold the tensile force properly. It is recommended to use another type of ASTM D638 - 02a which has a larger narrow section like type I (13 mm) and type III (19mm) so specimens are not broken when removed from the mold, and there isn’t any decrease in tensile strength.Density test showed that fiber mass does not significantly affect the density.

Genome-Wide Analysis of Syntenic Gene Deletion in the Grasses

Science.gov (United States)

Schnable, James C.; Freeling, Michael; Lyons, Eric

2012-01-01

The grasses, Poaceae, are one of the largest and most successful angiosperm families. Like many radiations of flowering plants, the divergence of the major grass lineages was preceded by a whole-genome duplication (WGD), although these events are not rare for flowering plants. By combining identification of syntenic gene blocks with measures of gene pair divergence and different frequencies of ancient gene loss, we have separated the two subgenomes present in modern grasses. Reciprocal loss of duplicated genes or genomic regions has been hypothesized to reproductively isolate populations and, thus, speciation. However, in contrast to previous studies in yeast and teleost fishes, we found very little evidence of reciprocal loss of homeologous genes between the grasses, suggesting that post-WGD gene loss may not be the cause of the grass radiation. The sets of homeologous and orthologous genes and predicted locations of deleted genes identified in this study, as well as links to the CoGe comparative genomics web platform for analyzing pan-grass syntenic regions, are provided along with this paper as a resource for the grass genetics community. PMID:22275519

Effectiveness of Domestic Wastewater Treatment Using a Bio-Hedge Water Hyacinth Wetland System

Directory of Open Access Journals (Sweden)

Alireza Valipour

2015-01-01

Full Text Available onstructed wetland applications have been limited by a large land requirement and capital investment. This study aimed to improve a shallow pond water hyacinth system by incorporating the advantages of engineered attached microbial growth technique (termed Bio-hedge for on-site domestic wastewater treatment. A laboratory scale continuous-flow system consists of the mesh type matrix providing an additional biofilm surface area of 54 m2/m3. Following one year of experimentation, the process showed more stability and enhanced performance in removing organic matter and nutrients, compared to traditional water hyacinth (by lowering 33%–67% HRT and facultative (by lowering 92%–96% HRT ponds. The wastewater exposed plants revealed a relative growth rate of 1.15% per day, and no anatomical deformities were observed. Plant nutrient level averaged 27 ± 1.7 and 44 ± 2.3 mg N/g dry weight, and 5 ± 1.4 & 9±1.2 mg P/g dry weight in roots and shoots, respectively. Microorganisms immobilized on Bio-hedge media (4.06 × 107 cfu/cm2 and plant roots (3.12 × 104 cfu/cm were isolated and identified (a total of 23 strains. The capital cost was pre-estimated for 1 m3/d wastewater at 78 US$/m3inflow and 465 US$/kg BOD5 removed. This process is a suitable ecotechnology due to improved biofilm formation, reduced footprint, energy savings, and increased quality effluent.

Grass-on-grass competition along a catenal gradient in mesic ...

African Journals Online (AJOL)

Three aboveground treatments (full light competition, no light competition and clipping to simulate grazing), and two belowground treatments (full belowground competition and belowground competition excluded by a root tube), were used. On all soil depths the three grass species differed in mean mass, with E. racemosa ...

Results from the 5-year SQ grass sublingual immunotherapy tablet asthma prevention (GAP) trial in children with grass pollen allergy.

Science.gov (United States)

Valovirta, Erkka; Petersen, Thomas H; Piotrowska, Teresa; Laursen, Mette K; Andersen, Jens S; Sørensen, Helle F; Klink, Rabih

2018-02-01

Allergy immunotherapy targets the immunological cause of allergic rhinoconjunctivitis and allergic asthma and has the potential to alter the natural course of allergic disease. The primary objective was to investigate the effect of the SQ grass sublingual immunotherapy tablet compared with placebo on the risk of developing asthma. A total of 812 children (5-12 years), with a clinically relevant history of grass pollen allergic rhinoconjunctivitis and no medical history or signs of asthma, were included in the randomized, double-blind, placebo-controlled trial, comprising 3 years of treatment and 2 years of follow-up. There was no difference in time to onset of asthma, defined by prespecified asthma criteria relying on documented reversible impairment of lung function (primary endpoint). Treatment with the SQ grass sublingual immunotherapy tablet significantly reduced the risk of experiencing asthma symptoms or using asthma medication at the end of trial (odds ratio = 0.66, P year posttreatment follow-up, and during the entire 5-year trial period. Also, grass allergic rhinoconjunctivitis symptoms were 22% to 30% reduced (P years). At the end of the trial, the use of allergic rhinoconjunctivitis pharmacotherapy was significantly less (27% relative difference to placebo, P < .001). Total IgE, grass pollen-specific IgE, and skin prick test reactivity to grass pollen were all reduced compared to placebo. Treatment with the SQ grass sublingual immunotherapy tablet reduced the risk of experiencing asthma symptoms and using asthma medication, and had a positive, long-term clinical effect on rhinoconjunctivitis symptoms and medication use but did not show an effect on the time to onset of asthma. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Aridity promotes bet hedging via delayed hatching: a case study with two temporary pond crustaceans along a latitudinal gradient.

Science.gov (United States)

Pinceel, Tom; Vanschoenwinkel, Bram; Hawinkel, Wouter; Tuytens, Karen; Brendonck, Luc

2017-05-01

Climate change does affect not only average rainfall and temperature but also their variation, which can reduce the predictability of suitable conditions for growth and reproduction. This situation is problematic for inhabitants of temporary waters whose reproductive success depends on rainfall and evaporation that determine the length of the aquatic phase. For organisms with long-lived dormant life stages, bet hedging models suggest that a fraction of these should stay dormant during each growing season to buffer against the probability of total reproductive failure in variable environments. Thus far, however, little empirical evidence supports this prediction in aquatic organisms. We study geographic variation in delayed hatching of dormant eggs in natural populations of two crustaceans, Branchinella longirostris and Paralimnadia badia, that occur in temporary rock pools along a 725 km latitudinal aridity gradient in Western Australia. Consistent with bet hedging theory, populations of both species were characterised by delayed hatching under common garden conditions and hatching fractions decreased towards the drier end of the gradient where the probability of reproductive success was shown to be lower. This decrease was most pronounced in the species with the longer maturation time, presumably because it is more sensitive to the higher prevalence of short inundations. Overall, these findings illustrate that regional variation in climate can be reflected in differential investment in bet hedging and hints at a higher importance of delayed hatching to persist when the climate becomes harsher. Such strategies could become exceedingly relevant as determinants of vulnerability under climate change.

Convex relationships in ecosystems containing mixtures of trees and grass

CSIR Research Space (South Africa)

Scholes, RJ

2003-12-01

Full Text Available The relationship between grass production and the quantity of trees in mixed tree-grass ecosystems (savannas) is convex for all or most of its range. In other words, the grass production declines more steeply per unit increase in tree quantity...

Bet-hedging as a complex interaction among developmental instability, environmental heterogeneity, dispersal, and life-history strategy.

Science.gov (United States)

Scheiner, Samuel M

2014-02-01

One potential evolutionary response to environmental heterogeneity is the production of randomly variable offspring through developmental instability, a type of bet-hedging. I used an individual-based, genetically explicit model to examine the evolution of developmental instability. The model considered both temporal and spatial heterogeneity alone and in combination, the effect of migration pattern (stepping stone vs. island), and life-history strategy. I confirmed that temporal heterogeneity alone requires a threshold amount of variation to select for a substantial amount of developmental instability. For spatial heterogeneity only, the response to selection on developmental instability depended on the life-history strategy and the form and pattern of dispersal with the greatest response for island migration when selection occurred before dispersal. Both spatial and temporal variation alone select for similar amounts of instability, but in combination resulted in substantially more instability than either alone. Local adaptation traded off against bet-hedging, but not in a simple linear fashion. I found higher-order interactions between life-history patterns, dispersal rates, dispersal patterns, and environmental heterogeneity that are not explainable by simple intuition. We need additional modeling efforts to understand these interactions and empirical tests that explicitly account for all of these factors.

Establishing native warm season grasses on Eastern Kentucky strip mines

Energy Technology Data Exchange (ETDEWEB)

Barnes, T.G.; Larkin, J.L.; Arnett, M.B. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Forestry

1998-12-31

The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat.

Establishing native warm season grasses on Eastern Kentucky strip mines

International Nuclear Information System (INIS)

Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

1998-01-01

The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat

Hedging to save face: a linguistic analysis of written comments on in-training evaluation reports.

Science.gov (United States)

Ginsburg, Shiphra; van der Vleuten, Cees; Eva, Kevin W; Lingard, Lorelei

2016-03-01

Written comments on residents' evaluations can be useful, yet the literature suggests that the language used by assessors is often vague and indirect. The branch of linguistics called pragmatics argues that much of our day to day language is not meant to be interpreted literally. Within pragmatics, the theory of 'politeness' suggests that non-literal language and other strategies are employed in order to 'save face'. We conducted a rigorous, in-depth analysis of a set of written in-training evaluation report (ITER) comments using Brown and Levinson's influential theory of 'politeness' to shed light on the phenomenon of vague language use in assessment. We coded text from 637 comment boxes from first year residents in internal medicine at one institution according to politeness theory. Non-literal language use was common and 'hedging', a key politeness strategy, was pervasive in comments about both high and low rated residents, suggesting that faculty may be working to 'save face' for themselves and their residents. Hedging and other politeness strategies are considered essential to smooth social functioning; their prevalence in our ITERs may reflect the difficult social context in which written assessments occur. This research raises questions regarding the 'optimal' construction of written comments by faculty.

Host-parasite coevolution can promote the evolution of seed banking as a bet-hedging strategy.

Science.gov (United States)

Verin, Mélissa; Tellier, Aurélien

2018-04-20

Seed (egg) banking is a common bet-hedging strategy maximizing the fitness of organisms facing environmental unpredictability by the delayed emergence of offspring. Yet, this condition often requires fast and drastic stochastic shifts between good and bad years. We hypothesize that the host seed banking strategy can evolve in response to coevolution with parasites because the coevolutionary cycles promote a gradually changing environment over longer times than seed persistence. We study the evolution of host germination fraction as a quantitative trait using both pairwise competition and multiple mutant competition methods, while the germination locus can be genetically linked or unlinked with the host locus under coevolution. In a gene-for-gene model of coevolution, hosts evolve a seed bank strategy under unstable coevolutionary cycles promoted by moderate to high costs of resistance or strong disease severity. Moreover, when assuming genetic linkage between coevolving and germination loci, the resistant genotype always evolves seed banking in contrast to susceptible hosts. Under a matching-allele interaction, both hosts' genotypes exhibit the same seed banking strategy irrespective of the genetic linkage between loci. We suggest host-parasite coevolution as an additional hypothesis for the evolution of seed banking as a temporal bet-hedging strategy. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Estimating grass-clover ratio variations caused by traffic intensities using image analysis

DEFF Research Database (Denmark)

Jørgensen, Rasmus Nyholm; Sørensen, Claus Grøn; Green, Ole

Grass and especially clover have a negative yield response as a function of  traffic intensity.  Conventional grass-clover production for silage have high traffic intensity due to fertilizing with slurry, cutting the grass, rolling the grass into swaths, and collecting and chopping the grass...... to fulfill the aim [1]http://www.ruralni.gov.uk/index/publications/press_articles/dairy-2/role-of-clover.htm...

Controlling grass weeds on hard surfaces

DEFF Research Database (Denmark)

Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

2012-01-01

An experiment was conducted on a specially designed hard surface to study the impact of time interval between flaming treatments on the regrowth and flower production of two grass weeds. The goal of this experiment was to optimize the control of annual bluegrass and perennial ryegrass, both species...... that are very difficult to control without herbicides. Aboveground biomass from 72 plants per treatment was harvested and dry weights were recorded at regular intervals to investigate how the plants responded to flaming. Regrowth of the grasses was measured by harvesting aboveground biomass 2 wk after......, as they did not increase the reduction of aboveground biomass compared with the 7-d treatment interval. Knowledge on the regrowth of grass weeds after flaming treatments provided by this study can help improve recommendations given to road keepers and park managers for management on these weeds. Nomenclature...

Microbial protein synthesis, digestion and lactation responses of cows to grass or grass-red clover silage diet supplemented with barley or oats

Directory of Open Access Journals (Sweden)

A. VANHATALO

2008-12-01

Full Text Available The study was conducted to evaluate effects of silage type (grass-red clover vs. pure grass and grain supplement (oats vs. barley on rumen fermentation, post-ruminal nutrient flows, diet digestion and milk production. Four primiparous Finnish Ayrshire cows fitted with cannulae in the rumen and duodenum were used in a 4 × 4 Latin square experiment with four 28-d experimental periods and 2 × 2 factorial arrangements of treatments. Using red clover-containing (40% silage rather than pure grass silage had minor effects on rumen fermentation or diet digestion but increased non-ammonia nitrogen (N flow in terms of increased flows of microbial and dietary N entering to the small intestine. This was reflected as a reduced ruminal N degradability on grass-red clover diets. Furthermore, grass-red clover diets in comparison to grass silage diets increased milk lactose concentration and yields of milk, protein and lactose. Feeding oats in replacement for barley had minor effects on rumen fermentation or post-ruminal non-ammonia N flows but reduced digestibility of organic matter and neutral detergent fibre in the diet. Using oats rather than barley increased yields of milk and lactose but reduced milk protein concentration. Oats also increased proportions of C18:0 and C18:1 in milk fat and reduced those of C10:0 to C16:0. It is concluded that inclusion of red clover and replacement of barley with oats in grass silage based diets have beneficial effects in dairy cow production.;

Estimating the energy requirements and CO{sub 2} emissions from production of the perennial grasses miscanthus, switchgrass and reed canary grass

Energy Technology Data Exchange (ETDEWEB)

Bullard, M.; Metcalfe, P.

2001-07-01

The perennial grasses miscanthus, reed canary and swithchgrass have attractions as energy crops in the United Kingdom: all have low demand for fertilizer and pesticide, and are harvested annually. Research on energy ratios and carbon ratios of the grasses is reported. A Microsoft Excel-based model was developed (from an ADAS database) and the input calculations and assumptions are explained. The study demonstrated the attractions of theses grasses as a source of fuel. The results agreed with those from a model developed for the SRC.

The effects of energy grass plantations on biodiversity

Energy Technology Data Exchange (ETDEWEB)

Semere, T; Slater, F

2005-07-01

The ecological impact on local wildlife of biomass plantations of three different species of grasses has been monitored in the years 2002 to 2004 inclusive at farms in Herefordshire UK. Two of the grasses were not native to Britain. Wildlife monitored included ground flora, beetles, insects, birds, small mammals, butterflies, bees and hoverflies. The results provide a baseline of biodiversity data from biomass farms in England, although due to poor crop growth, the data from the switch-grass plantation was incomplete. The surveys were carried out by Cardiff University supported financially by the DTI.

The effects of energy grass plantations on biodiversity

International Nuclear Information System (INIS)

Semere, T.; Slater, F.

2005-01-01

The ecological impact on local wildlife of biomass plantations of three different species of grasses has been monitored in the years 2002 to 2004 inclusive at farms in Herefordshire UK. Two of the grasses were not native to Britain. Wildlife monitored included ground flora, beetles, insects, birds, small mammals, butterflies, bees and hoverflies. The results provide a baseline of biodiversity data from biomass farms in England, although due to poor crop growth, the data from the switch-grass plantation was incomplete. The surveys were carried out by Cardiff University supported financially by the DTI

Functional immunoglobulin E cross-reactivity between Pas n 1 of Bahia grass pollen and other group 1 grass pollen allergens.

Science.gov (United States)

Davies, J M; Dang, T D; Voskamp, A; Drew, A C; Biondo, M; Phung, M; Upham, J W; Rolland, J M; O'Hehir, R E

2011-02-01

Grass pollens are major triggers of allergic rhinitis and asthma, but the immunological relationships between pollen allergens of the subtropical Bahia grass, Paspalum notatum, and temperate grasses are unresolved. To assess serum IgE cross-reactivity between subtropical P. notatum and temperate Lolium perenne (Ryegrass) pollen allergens. Serum IgE reactivities of grass pollen-allergic patients with P. notatum, L. perenne and Cynodon dactylon (Bermuda grass) pollen extracts and their respective purified group 1 allergens, Pas n 1, Lol p 1 and Cyn d 1, were compared by immunoblotting, ELISA and basophil activation. In a cohort of 51 patients from a temperate region, a high frequency of IgE reactivity with each grass pollen was detected, but reactivity with L. perenne pollen was substantially greater than with P. notatum and C. dactylon pollen. Similarly, serum IgE reactivity with Lol p 1 was greater than with Pas n 1 or Cyn d 1. For seven of eight sera studied in detail, asymmetric serum IgE cross-reactivity was observed; L. perenne pollen inhibited IgE reactivity with P. notatum pollen but not the converse, and IgE reactivity with Pas n 1 was inhibited by Lol p 1 but IgE reactivity with Lol p 1 was not inhibited by Pas n 1 or Cyn d 1. Importantly, P. notatum pollen and Pas n 1 activated basophils in grass pollen-allergic patients from a temperate region, although stimulation was greater by pollen of L. perenne than P. notatum or C. dactylon, and by Lol p 1 than Pas n 1 or Cyn d 1. In contrast, a cohort of 47 patients from a subtropical region showed similar IgE reactivity with P. notatum and L. perenne pollen, and reciprocal cross-inhibition of IgE reactivity between L. perenne and P. notatum. Pollen allergens of the subtropical P. notatum, including Pas n 1, show clinically relevant IgE cross-reactivity with pollen allergens of L. perenne but also species-specific IgE reactivity. © 2011 Blackwell Publishing Ltd.

High-biomass C4 grasses-Filling the yield gap.

Science.gov (United States)

Mullet, John E

2017-08-01

A significant increase in agricultural productivity will be required by 2050 to meet the needs of an expanding and rapidly developing world population, without allocating more land and water resources to agriculture, and despite slowing rates of grain yield improvement. This review examines the proposition that high-biomass C 4 grasses could help fill the yield gap. High-biomass C 4 grasses exhibit high yield due to C 4 photosynthesis, long growth duration, and efficient capture and utilization of light, water, and nutrients. These C 4 grasses exhibit high levels of drought tolerance during their long vegetative growth phase ideal for crops grown in water-limited regions of agricultural production. The stems of some high-biomass C 4 grasses can accumulate high levels of non-structural carbohydrates that could be engineered to enhance biomass yield and utility as feedstocks for animals and biofuels production. The regulatory pathway that delays flowering of high-biomass C 4 grasses in long days has been elucidated enabling production and deployment of hybrids. Crop and landscape-scale modeling predict that utilization of high-biomass C 4 grass crops on land and in regions where water resources limit grain crop yield could increase agricultural productivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Ground beetle (Coleoptera: Carabidae) assemblages in narrow hedgerows in a Danish agricultural landscape

DEFF Research Database (Denmark)

Lövei, G. L.; Magura, T.

2015-01-01

Sorbus intermedia), and the non-native spruce (Picea spp.). We hypothesised that hedgerows with deciduous trees harbour more diverse ground beetle assemblages than hedges composed of non-native conifer trees. We also investigated which vegetation structure characteristics might influence the ground...

Dredging Operations Technical Support Program. Long-Term Monitoring of Habitat Development at Upland and Wetland Dredged Material Disposal Sites 1974-1982.

Science.gov (United States)

1985-07-01

and insecticides , and the chlorinated hydrocarbon, Kepone, from an industrial site at Hopewell. 34. The area averages 112.3 cm of rainfall per year and...aster X X X X X . False indigo-bush X False nettle X X X - " Field mint X Flowering spiderwort X . Foxta.1l grass X Giant cutgrass X X X . %. Goose grass...Grape X x Green ash X X ’ Greenbriar X " Groundnut X X Halberd-leaved tearthuinb X Hedge bindweed X X Horse nettle X X , Indian hemp X Ironweed X Ivy

Grass Rooting the System

Science.gov (United States)

Perlman, Janice E.

1976-01-01

Suggests a taxonomy of the grass roots movement and gives a general descriptive over view of the 60 groups studied with respect to origin, constituency, size, funding, issues, and ideology. (Author/AM)

A snapshot of soil water composition as an indicator of contrasted redox environments in a hedged farmland plot.

Science.gov (United States)

Albéric, Patrick; Vennink, Aurélie; Cornu, Sophie; Bourennane, Hocine; Bruand, Ary

2009-10-15

While soil water composition has long been recognised as being related to soil type (characteristics of the horizons), the influence of structures resulting from agricultural activities (hedges, ditches, wheel ruts, etc) is still under discussion. This work was undertaken to show that a snapshot of spatial variability of the geochemical characteristics of soil water at the scale of a plot can improve our understanding of soil geochemistry in a farmland setting. We selected a 3 hectare hedged plot located on a hillside, limited by a stream and used as pasture where soils have developed in weathered gneiss. The water depth, electrical conductivity, major ions, temperature, pH, dissolved organic carbon (DOC) content, dissolved oxygen content, fluorescence, alkalinity, Fe(2+), Mn(2+), NO(2)(-), Fe(III) and F(-) contents were measured in 62 auger holes randomly drilled on the site. Four sectors were identified in order to describe the distribution of the main geochemical parameters. Electrical conductivity and some major ions, especially sulphate, had larger concentrations near hedges where oxic conditions prevailed. These features were attributed to the impact of the linear anthropogenic network on the circulation of subsurface soil waters and evapo-transpiration and represent sector I. Dissolved Mn was an indicator of well channelled runoff subsurfaces facilitating the circulation of more highly reducing water (sector III), while DOC probably marked areas drained less well, with a prolonged contact time between soil solutions and organic topsoil horizons (sector II). The presence of dissolved Mn and Fe(II) indicates bottomland anoxic conditions (sector IV). It is concluded that a survey of the chemical composition of soil water may be a direct approach to show the influence of permanent structures on current soil properties and dynamics.

Hilly grasses and leaves: a promising unconventional feed resource for livestock.

OpenAIRE

Hossain M.E.; Karim M.H.; Ahmed M.I.; Sultana S.A.

2016-01-01

The study was undertaken to find out the chemical composition of different hilly grasses and leaves available in Bandarban areas of Bangladesh. Total 10 different hilly grasses and leaves such as Bottle gourd leaf (Lagenaria siceraria), Castor bean leaf (Ricinus communis), Cogon grass (Imperata cylindrica), Dhol kolmi (Ipomoea carnea), Giant reed leaf (Arundo donax), Hilly grass (Cynodon dactylon), Pithraj leaf (Aphanamixis polystachya), Sal leaf (Shorea robusta), Shegun leaf (Tectona grandis...

Effect of machinery wheel load on grass yield

DEFF Research Database (Denmark)

Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian

2010-01-01

Effect of machinery wheel load on grass   Ole Green1, Rasmus N. Jørgensen2, Kristian Kristensen3, René Gislum3, Dionysis Bochtis1, & Claus G. Sørensen1   1University of Aarhus, Dept. of Agricultural Engineering 2University of Southern Denmark, Inst. of Chemical Eng., Biotechnology and Environmental...... 3University of Aarhus, Dept. of Genetics and Biotechnology   Corresponding author: Ole Green Address & e-mail: Research Centre Foulum, Blichers Allé 20, 8830 Tjele. Ole.Green@agrsci.dk     Abstract   Different traffic intensities have been shown to have a negative influence on the yield of grass...... and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffic intensities with 35 replicates and 1 traffic free treatment with 245 replicates, totalling 17...

Alley cropping of legumes with grasses as forages : Effect of different grass species and row spacing of gliricidia on the growth and biomass production of forages

Directory of Open Access Journals (Sweden)

Siti Yuhaeni

1998-12-01

Full Text Available A study to evaluate the effect of different grass species and row spacing of gliricidia (Gliricidia sepium on the growth and biomass production of forages in an alley cropping system was conducted in two different agroclimatical zones i.e. Bogor, located at 500 m a .s .l . with an average annual rainfall of 3,112 nun/year and Sukabumi located at 900 m a .s .l . with an average annual rainfall of 1,402 mm/year . Both locations have low N, P, and K content and the soil is classified as acidic. The experimental design used was a split plot design with 3 replicates . The main plots were different grass species i.e. king grass (Pennisetum purpureum x P. typhoides and elephant grass (P. purpureum. The sub plots were the row spacing of gliricidia at 2, 3, 4, 6 m (1 hedgerows and 4 m (2 hedgerows. The results indicated that the growth and biomass production of grasses were significantly affected (P<0 .05 by the treatments in Bogor. The highest biomass productions was obtained from the 2 m row spacing which gave the highest dry matter production of grasses (1 .65 kg/hill and gliricidia (0 .086 kg/tree . In Sukabumi the growth and biomass production of grasses and gliricidia were also significantly affected by the treatments . The highest dry matter production was obtained with 2 m row spacing (dry matter of grasses and gliricidia were 1 .12 kg/hill and 0 .026 kg/tree, respectively . The result further indicated that biomass production of forages increased with the increase in gliricidia population. The alley cropping system wich is suitable for Bogor was the 2 m row spacing of gliricidia intercropped with either king or elephant grass and for Sukabumi 2 and 4 m (2 rows of gliricidia row spacing intercropped with king or elephant grass .

Multi-Objective Optimization of the Hedging Model for reservoir Operation Using Evolutionary Algorithms

Directory of Open Access Journals (Sweden)

sadegh sadeghitabas

2015-12-01

Full Text Available Multi-objective problems rarely ever provide a single optimal solution, rather they yield an optimal set of outputs (Pareto fronts. Solving these problems was previously accomplished by using some simplifier methods such as the weighting coefficient method used for converting a multi-objective problem to a single objective function. However, such robust tools as multi-objective meta-heuristic algorithms have been recently developed for solving these problems. The hedging model is one of the classic problems for reservoir operation that is generally employed for mitigating drought impacts in water resources management. According to this method, although it is possible to supply the total planned demands, only portions of the demands are met to save water by allowing small deficits in the current conditions in order to avoid or reduce severe deficits in future. The approach heavily depends on economic and social considerations. In the present study, the meta-heuristic algorithms of NSGA-II, MOPSO, SPEA-II, and AMALGAM are used toward the multi-objective optimization of the hedging model. For this purpose, the rationing factors involved in Taleghan dam operation are optimized over a 35-year statistical period of inflow. There are two objective functions: a minimizing the modified shortage index, and b maximizing the reliability index (i.e., two opposite objectives. The results show that the above algorithms are applicable to a wide range of optimal solutions. Among the algorithms, AMALGAM is found to produce a better Pareto front for the values of the objective function, indicating its more satisfactory performance.

Energy evaluation of fresh grass in the diets of lactating dairy cows

NARCIS (Netherlands)

Bruinenberg, M.H.; Zom, R.L.G.; Valk, H.

2002-01-01

The discrepancy between the estimated feeding value of fresh grass and the output per kg grass in terms of milk and maintenance was studied by evaluating 12 experiments with grass-fed dairy cows. The percentage grass in the diets varied between 40 and 90. Intake and milk production were recorded

Ecophysiological responses of native and invasive grasses to simulated warming and drought

Science.gov (United States)

Ravi, S.; Law, D. J.; Wiede, A.; Barron-Gafford, G. A.; Breshears, D. D.; Dontsova, K.; Huxman, T. E.

2011-12-01

Climate models predict that many arid regions around the world - including the North American deserts - may become affected more frequently by recurrent droughts. At the same time, these regions are experiencing rapid vegetation transformations such as invasion by exotic grasses. Thus, understanding the ecophysiological processes accompanying exotic grass invasion in the context of rising temperatures and recurrent droughts is fundamental to global change research. Under ambient and warmer (+ 4° C) conditions inside the Biosphere 2 facility, we compared the ecophysiological responses (e.g. photosynthesis, stomatal conductance, pre-dawn leaf water potential, light & CO2 response functions, biomass) of a native grass - Heteropogan contortus (Tangle head) and an invasive grass - Pennisetum ciliare (Buffel grass) growing in single and mixed communities. Further, we monitored the physiological responses and mortality of these plant communities under moisture stress conditions, simulating a global change-type-drought. The results indicate that the predicted warming scenarios may enhance the invasibility of desert landscapes by exotic grasses. In this study, buffel grass assimilated more CO2 per unit leaf area and out-competed native grasses more efficiently in a warmer environment. However, scenarios involving a combination of drought and warming proved disastrous to both the native and invasive grasses, with drought-induced grass mortality occurring at much shorter time scales under warmer conditions.

The Potential of Cellulosic Ethanol Production from Grasses in Thailand

Directory of Open Access Journals (Sweden)

Jinaporn Wongwatanapaiboon

2012-01-01

Full Text Available The grasses in Thailand were analyzed for the potentiality as the alternative energy crops for cellulosic ethanol production by biological process. The average percentage composition of cellulose, hemicellulose, and lignin in the samples of 18 types of grasses from various provinces was determined as 31.85–38.51, 31.13–42.61, and 3.10–5.64, respectively. The samples were initially pretreated with alkaline peroxide followed by enzymatic hydrolysis to investigate the enzymatic saccharification. The total reducing sugars in most grasses ranging from 500–600 mg/g grasses (70–80% yield were obtained. Subsequently, 11 types of grasses were selected as feedstocks for the ethanol production by simultaneous saccharification and cofermentation (SSCF. The enzymes, cellulase and xylanase, were utilized for hydrolysis and the yeasts, Saccharomyces cerevisiae and Pichia stipitis, were applied for cofermentation at 35°C for 7 days. From the results, the highest yield of ethanol, 1.14 g/L or 0.14 g/g substrate equivalent to 32.72% of the theoretical values was obtained from Sri Lanka ecotype vetiver grass. When the yields of dry matter were included in the calculations, Sri Lanka ecotype vetiver grass gave the yield of ethanol at 1,091.84 L/ha/year, whereas the leaves of dwarf napier grass showed the maximum yield of 2,720.55 L/ha/year (0.98 g/L or 0.12 g/g substrate equivalent to 30.60% of the theoretical values.

Market efficiency, cross hedging and price forecasts: California's natural-gas markets

International Nuclear Information System (INIS)

Woo, C.K.; Olson, A.; Horowitz, I.

2006-01-01

An extensive North American pipeline grid that physically integrates individual natural-gas markets, in conjunction with economic ties binding the California markets to those at Henry Hub, Louisiana and the New York mercantile exchange via an array of financial instruments, suggests that the spot prices at Henry Hub will impact those in California. We verify the suggestion via a partial-adjustment regression model, thus affirming that California traders can exploit the cross-hedging opportunities made available to them via market integration with Henry Hub, and that they can accurately forecast the price they will have to pay to meet future demand based solely on the price of futures at Henry Hub and the price of a California natural-gas basis swaps contract. (author)

From Socialism to Hedge Fund: The Human Element and the New History of Capitalism

Directory of Open Access Journals (Sweden)

David Huyssen

2015-08-01

Full Text Available Alfred Winslow Jones was a socialist who founded the first hedge fund in 1949. He had been U.S. Vice Consul in Berlin from 1931 to 1932, Soviet sympathizer and anti-Nazi spy with dissident German communists, humanitarian observer during the Spanish Civil War, acclaimed sociologist of class, and an editor for Fortune magazine. At every stage of his life, Jones occupied positions of advantage, and his invention of the modern hedge fund has had an outsized impact on global capitalism’s contemporary round of financialization. On its face, then, his life would appear to offer ideal material for a “great-man” biography. Yet this “great man” also wrestled with the continual recognition that structural forces were undermining his fondest hopes for social change. Following Georgi Derluguian, Giovanni Arrighi, and Marc Bloch, this article proposes a world-system biography of Jones as a method better suited for mapping the internal dialectics of twentieth-century capitalism, using Jones as a human connection between cyclical and structural transformations of capitalism, and across changes of phase from financial to material expansion—and back again. On another level, it suggests a theoretical reorientation—toward what Bloch called “the human element”—for studies of capitalism’s cultural and material history. It argues that such a reorientation would hold rewards for the “new history of capitalism” field, which until now has pursued its quarry primarily by tracing the movements of commodities, capital, institutions, and ideas.

Perennial Grass Bioenergy Cropping on Wet Marginal Land

NARCIS (Netherlands)

Das, Srabani; Teuffer, Karin; Stoof, Cathelijne R.; Walter, Michael F.; Walter, M.T.; Steenhuis, Tammo S.; Richards, Brian K.

2018-01-01

The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate

Tensile fracture properties of seven tropical grasses at different phenological stages

NARCIS (Netherlands)

Jacobs, A.A.A.; Scheper, J.A.; Benvenutti, M.A.; Gordon, I.J.; Poppi, D.P.; Elgersma, A.

2011-01-01

The intake of forage grasses by grazing ruminants is closely related to the mechanical fracture properties of grasses. The relationship between the tensile fracture properties of grasses and foraging behaviour is of particular importance in tropical reproductive swards composed of both stems and

How much gas can we get from grass?

International Nuclear Information System (INIS)

Nizami, A.S.; Orozco, A.; Groom, E.; Dieterich, B.; Murphy, J.D.

2012-01-01

Highlights: ► We highlight the various results for biomethane potential that may be obtained from the same grass silage. ► The results indicated that methane potential varied from 350 to 493 L CH 4 kg −1 VS added for three different BMP procedures. ► We compare two distinct digestion systems using the same grass. ► A two stage wet system achieved 451 L CH 4 kg −1 VS added over a 50 day retention period. ► A two phase system achieved 341 L CH 4 kg −1 VS added at a 30 day retention time. -- Abstract: Grass biomethane has been shown to be a sustainable gaseous transport biofuel, with a good energy balance, and significant potential for economic viability. Of issue for the designer is the variation in characteristics of the grass depending on location of source, time of cut and species. Further confusion arises from the biomethane potential tests (BMP) which have a tendency to give varying results. This paper has dual ambitions. One of these is to highlight the various results for biomethane potential that may be obtained from the same grass silage. The results indicated that methane potential from the same grass silage varied from 350 to 493 L CH 4 kg −1 VS added for three different BMP procedures. The second ambition is to attempt to compare two distinct digestion systems again using the same grass: a two stage continuously stirred tank reactor (CSTR); and a sequentially fed leach bed reactor connected to an upflow anaerobic sludge blanket (SLBR–UASB). The two engineered systems were designed, fabricated, commissioned and operated at small pilot scale until stable optimal operating conditions were reached. The CSTR system achieved 451 L CH 4 kg −1 VS added over a 50 day retention period. The SLBR–UASB achieved 341 L CH 4 kg −1 VS added at a 30 day retention time.

Effects of rye grass coverage on soil loss from loess slopes

Directory of Open Access Journals (Sweden)

Yuequn Dong

2015-09-01

Full Text Available Vegetative coverage is commonly used to reduce urban slope soil erosion. Laboratory experimental study on soil erosion under grass covered slopes is conventionally time and space consuming. In this study, a new method is suggested to study the influences of vegetation coverage on soil erosion from a sloped loess surface under three slope gradients of 5°, 15°, and 25°; four rye grass coverages of 0%, 25%, 50%, and 75%; and three rainfall intensities of 60, 90, and 120 mm/h with a silt-loamy loess soil. Rye grasses were planted in the field with the studied soil before being transplanted into a laboratory flume. Grass was allowed to resume growth for a period before the rain simulation experiment. Results showed that the grass cover reduced soil erosion by 63.90% to 92.75% and sediment transport rate by 80.59% to 96.17% under different slope gradients and rainfall intensities. The sediment concentration/sediment transport rate from bare slope was significantly higher than from a grass-covered slope. The sediment concentration/transport rate from grass-covered slopes decreased linearly with grass coverage and increased with rainfall intensity. The sediment concentration/transport rate from the bare slope increased as a power function of slope and reached the maximum value at the gradient of about 25°, whereas that from grass-covered slope increased linearly and at much lower levels. The results of this study can be used to estimate the effect of vegetation on soil erosion from loess slopes.

Narrow, duplicated internal auditory canal

Energy Technology Data Exchange (ETDEWEB)

Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

2003-05-01

A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

Flooding correlations in narrow channel

International Nuclear Information System (INIS)

Kim, S. H.; Baek, W. P.; Chang, S. H.

1999-01-01

Heat transfer in narrow gap is considered as important phenomena in severe accidents in nuclear power plants. Also in heat removal of electric chip. Critical heat flux(CHF) in narrow gap limits the maximum heat transfer rate in narrow channel. In case of closed bottom channel, flooding limited CHF occurrence is observed. Flooding correlations will be helpful to predict the CHF in closed bottom channel. In present study, flooding data for narrow channel geometry were collected and the work to recognize the effect of the span, w and gap size, s were performed. And new flooding correlations were suggested for high-aspect-ratio geometry. Also, flooding correlation was applied to flooding limited CHF data

Bet hedging in a warming ocean: predictability of maternal environment shapes offspring size variation in marine sticklebacks.

Science.gov (United States)

Shama, Lisa N S

2015-12-01

Bet hedging at reproduction is expected to evolve when mothers are exposed to unpredictable cues for future environmental conditions, whereas transgenerational plasticity (TGP) should be favoured when cues reliably predict the environment offspring will experience. Since climate predictions forecast an increase in both temperature and climate variability, both TGP and bet hedging are likely to become important strategies to mediate climate change effects. Here, the potential to produce variably sized offspring in both warming and unpredictable environments was tested by investigating whether stickleback (Gasterosteus aculeatus) mothers adjusted mean offspring size and within-clutch variation in offspring size in response to experimental manipulation of maternal thermal environment and predictability (alternating between ambient and elevated water temperatures). Reproductive output traits of F1 females were influenced by both temperature and environmental predictability. Mothers that developed at ambient temperature (17 °C) produced larger, but fewer eggs than mothers that developed at elevated temperature (21 °C), implying selection for different-sized offspring in different environments. Mothers in unpredictable environments had smaller mean egg sizes and tended to have greater within-female egg size variability, especially at 21 °C, suggesting that mothers may have dynamically modified the variance in offspring size to spread the risk of incorrectly predicting future environmental conditions. Both TGP and diversification influenced F2 offspring body size. F2 offspring reared at 21 °C had larger mean body sizes if their mother developed at 21 °C, but this TGP benefit was not present for offspring of 17 °C mothers reared at 17 °C, indicating that maternal TGP will be highly relevant for ocean warming scenarios in this system. Offspring of variable environment mothers were smaller but more variable in size than offspring from constant environment

Seasonal variation in diurnal atmospheric grass pollen concentration profiles

DEFF Research Database (Denmark)

Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

2014-01-01

the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

Response of itchgrass and johnson grass to asulam/dalapon combinations

International Nuclear Information System (INIS)

Hook, B.J.

1986-01-01

Activities of asumlam [methyl[(4-aminophenyl)sulfonyl]carbamate], dalapon (2,2-dichloropropionic acid) and asulam/dalapon combinations on itchgrass (Rottboellia exaltata L.f.) and johnson grass [Sorghum halepense (L.) Pers.] were examined. When metabolism of 14 C-asulam was monitored, seven days after application, 97-100% of recovered 14 C co-chromatographed with 14 C-asulam. Itchgrass exhibited rapid uptake of 14 C-asulam within 8 hr after application. Asumlam concentrations remained constant in the plant between 8 and 72 hr. Johnson grass plants showed a differential response to asulam and asulam/dalapon treatments. Asulam-treated johnson grass absorbed 26-34% 14 C within 2 hr with no future significant increase in absorption in absorption through 72 hr. Treatment of johnson grass with asulam/dalapon enhanced 14 C absorption with time. At 24 and 72 hr 14 C levels were double that absorbed from treatment of asulam alone. Movement of 14 C-asulam in the apoplast and symplast of both itchgrass and johnson grass was noted. The highest radiolabel accumulated in the lower leaves of itchgrass and remained in the treated leaf of johnson grass

Native Grass Community Management Plan for the Oak Ridge Reservation

Energy Technology Data Exchange (ETDEWEB)

Ryon, Michael G [ORNL; Parr, Patricia Dreyer [ORNL; Cohen, Kari [ORNL

2007-06-01

Land managers at the Department of Energy's Oak Ridge National Laboratory in East Tennessee are restoring native warm-season grasses and wildflowers to various sites across the Oak Ridge Reservation (ORR). Some of the numerous benefits to planting native grasses and forbs include improved habitat quality for wildlife, improved aesthetic values, lower long-term maintenance costs, and compliance with Executive Order 13112 (Clinton 1999). Challenges to restoring native plants on the ORR include the need to gain experience in establishing and maintaining these communities and the potentially greater up-front costs of getting native grasses established. The goals of the native grass program are generally outlined on a fiscal-year basis. An overview of some of the issues associated with the successful and cost-effective establishment and maintenance of native grass and wildflower stands on the ORR is presented in this report.

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

Science.gov (United States)

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

2017-02-01

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

Grass genomes

OpenAIRE

Bennetzen, Jeffrey L.; SanMiguel, Phillip; Chen, Mingsheng; Tikhonov, Alexander; Francki, Michael; Avramova, Zoya

1998-01-01

For the most part, studies of grass genome structure have been limited to the generation of whole-genome genetic maps or the fine structure and sequence analysis of single genes or gene clusters. We have investigated large contiguous segments of the genomes of maize, sorghum, and rice, primarily focusing on intergenic spaces. Our data indicate that much (>50%) of the maize genome is composed of interspersed repetitive DNAs, primarily nested retrotransposons that in...

Anaerobic co-digestion of sewage sludge with shredded grass from public green spaces.

Science.gov (United States)

Hidaka, Taira; Arai, Sayuri; Okamoto, Seiichiro; Uchida, Tsutomu

2013-02-01

Adding greenery from public spaces to the co-digestion process with sewage sludge was evaluated by shredding experiments and laboratory-scale batch and continuous mesophilic anaerobic fermentation experiments. The ratio of the shredded grass with 20mm or less in length by a commercially available shredder was 93%. The methane production was around 0.2NL/gVS-grass in the batch experiment. The continuous experiment fed with sewage sludge and shredded grass was stably operated for 81days. The average methane production was 0.09NL/gVS-grass when the TS ratio of the sewage sludge and the grass was 10:1. This value was smaller than those of other reports using grass silage, but the grass species in this study were not managed, and the collected grass was just shredded and not ensiled before feeding to the reactor for simple operation. The addition of grass to a digester can improve the carbon/nitrogen ratio, methane production and dewaterability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of some macromineral concentration of a grass/ legume ...

African Journals Online (AJOL)

Assessment of some macromineral concentration of a grass/ legume sward in ... Bulletin of Animal Health and Production in Africa ... The study aimed to determine the concentration of some macromineral elements in the grass/legume pasture ...

Environmental performance assessment of Napier grass for bioenergy production

DEFF Research Database (Denmark)

Nimmanterdwong, Prathana; Chalermsinsuwan, Benjapon; Østergård, Hanne

2017-01-01

equivalence. This idea provides the quantitative indicators involving the resource use and the percent renewability of the systems. For the proposed biorefinery model, Napier grass (Pennisetum purpureum) grown in Thailand was used as lignocellulosic feedstock. An emergy assessment was performed in two parts...... cultivation and biorefinery stages. For Napier grass cultivation, most of the emergy support came from local resources in term of evapotranspiration of Napier grass (33%) and the diesel consumption during the cultivation process (21%). The emergy sustainability indicator of the cultivation was 0...

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

Science.gov (United States)

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

2015-01-01

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

我国上市公司金融性套期保值决策的动机研究%Analysis on the Motives of Financial Hedging of Chinese A-Share Listed Company

Institute of Scientific and Technical Information of China (English)

郭玲; 阴永晟

2009-01-01

近年来,我国上市公司的金融性套期保值交易增长迅速.本文以国外公司套期保值动机理论作为分析框架,根据我国的市场环境和上市公司的财务特征构建解释变量,对上市公司金融性套期保值决策的动机进行实证检验和分析.研究表明,降低财务困境成本和债务代理成本是我国上市公司全融性套期保值决策的主要动机:此外,公司有现金分红需要、股权结构中有外资法人股或境外上市股时,公司越有动机进行金融性套期保值,并且套期保值具有规模经济效应.%Despite the use of derivatives for corporate hedging in China has been growing fast,the relevant domestic research is still in the primary stage,for example there is 110 systemalic research on the feasibility of corporate hedging theory and empirical research in China.This paper analyzed the corporate hedging theory and made an empirical research on the determinants of hedging strategies with China A-share listed Cmpa-nies after constructing the variables under the analysis of unique characteristics of Chinese business environ-ment.This paperdiscovers that the main motives of our listed companies financial hedging decision - making are reducing financial distress costs and agency costs of debt.In addition,a company has the need of cash dividend.A company with foreign legal person stocks or foreign listing stocks,has greater motives to finan cial hedging,which has the effect of economy of scale.

Agricultural field reclamation utilizing native grass crop production

Science.gov (United States)

J. Cure

2013-01-01

Developing a method of agricultural field reclamation to native grasses in the Lower San Pedro Watershed could prove to be a valuable tool for educational and practical purposes. Agricultural field reclamation utilizing native grass crop production will address water table depletion, soil degradation and the economic viability of the communities within the watershed....

Futures and forward contract as a route of hedging the risk

Directory of Open Access Journals (Sweden)

Misbahul Islam

2015-10-01

Full Text Available In the present highly uncertain business scenario, the importance of risk management is much greater than ever before. Variations in the prices of agricultural and non-agricultural commodities are induced, over time, by demand-supply dynamics. The last two decades have witnessed many-fold increase in the volume of international trade and business due to the wave of globalization and liberalization sweeping across the world. This has led to rapid and unpredictable variations in financial assets prices, interest rates and exchange rates, and subsequently, to exposing the corporate world to an unwieldy financial risk. As a result, financial markets have experienced rapid variations in interest and exchange rates, stock market prices thus exposing the corporate world to a state of growing financial risk. The emergence of derivatives market is an ingenious feat of financial engineering that provides an effective and less costly solution to the problem of risk that is embedded in the price unpredictability of the underlying asset. Derivatives provide an effective solution to the problem of risk caused by uncertainty and volatility in underlying assets. These are the financial instruments that are linked to a specific financial instrument or indicator or commodity and through which specific risks can be traded in financial markets in their own right. In actual practice there are various different types of derivatives but this paper emphasizes on the two most important types of derivatives i.e. futures and forward contracts. These two are the most commonly used types of derivatives in financial markets. We can hedge the risk of price variations in stocks, bonds, commodities, currencies, interest rates, market indices etc. This study is about the futures and forward contracts. This paper presents various types of futures and forward contract and what advantages and disadvantages these two important types of derivatives have? It also includes that how

Impact on Clover-Grass Yield from Wheel Load and Tyre Pressure

DEFF Research Database (Denmark)

Green, Ole; Jørgensen, Rasmus Nyholm; Sørensen, Claus Aage Grøn

2009-01-01

Traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffi...

Identification of grazed grasses using epidermal characters | R ...

African Journals Online (AJOL)

The use of anatomical features of the abaxial epidermis of grasses is discussed for the identification of fragments of epidermis present in samples of rumen. The reliability of this technique, and the variation of the epidermal characters in two widely distributed species of grass, is given. A "Key" to identity certain genera of ...

Rehabilitation experiment by phytoremediation using lawn grass

International Nuclear Information System (INIS)

2012-08-01

Measures against environmental contamination by radioactive materials originated from the Fukushima Nuclear Accident (May, 2011), are being conducted in Fukushima and surrounding prefectures. Regarding to the measures, a phytoremediation experiment with several types of lawn grasses in a field scale have been carried out. Lawn grasses are generally characterized by shallow rhizosphere, high density and root mat formation. Decontamination effectiveness of radioactive cesium by plant uptake and by sod removing was investigated. As a result, the range of decontamination factors by plant uptake was below than 1% because of low transfer rate form soil to plant. On the other hand, maximum decontamination factor by sod removing reached about 100%. Decontamination activities with various methods will be implemented according to the national decontamination policy and related plans in each municipality. The phytoremediation method with lawn grass would be applicable in limited circumstances. (author)

Turbulent transfer characteristics of radioiodine effluents from air to grass

Energy Technology Data Exchange (ETDEWEB)

Markee, E. H. [ARFRO, Environmental Science Services Administration, Idaho Falls, Idaho (United States)

1967-07-01

A total of 20 controlled field releases of radioiodine have been performed at the National Reactor Testing Station in Idaho as a portion of a program to study the transmission of gaseous radioiodine through the air-vegetation-cow-milk-human chain. Most of the releases were conducted over typical pasture grasses during different wind and stability conditions. Radioiodine adherence to grass and carbon plates was measured during most of the tests. Vertical air concentration profiles and turbulence parameters were measured to determine flux characteristics. Analysis of the data reveals the complex interdisciplinary nature of transfer of radioiodine from air to a natural surface. The data are in reasonable agreement with the deposition models of Sheppard and Chamberlain when corrections for the physical and biological receptiveness of the grass and grass density are made. The average ratios of momentum to mass flux were found to be 0.9 in stable conditions and 1.4 in unstable conditions. These ratios demonstrate the effect on mass flux in the lowest 4m by a surface that acts as a partial sink for gaseous effluents. This series of releases indicates the need for further research on the biological receptiveness of grass and turbulent transfer within a grass canopy. (author)

A Study on the risk-return characteristics and the diversification benefit of the Hedge Fund industry

OpenAIRE

Bagaria, Neha

2007-01-01

Hedge funds with their dynamic trading strategies have gained great popularity in the past decade and have been found to provide significant diversification benefits to a traditional portfolio of assets. As an investment strategy they assure higher returns at a lower risk. Thus we will investigate its unique characteristics and its relation with the S&P 500 index through various quantitative tools like simple regression analysis, Sharpe ratios and graphical and correlation analysis of the dif...

Rooting stem cuttings of northern red oak (Quercus rubra L.) utilizing hedged stump sprouts formed on recently felled trees

Science.gov (United States)

Matthew H. Gocke; Daniel J. Robinson

2010-01-01

The ability to root stem cuttings collected from hedged stump sprouts formed on recently felled trees was evaluated for 26 codominant northern red oak (Quercus rubra L.) trees growing in Durham County, NC. Sprouting occurred, the same year as felling, on 23 of the 26 tree stumps and sprout number was significantly and positively correlated with stump diameter. The...

Sources of N2O in organic grass-clover pastures

OpenAIRE

Ambus, P.

2002-01-01

Organic farming practises, and in particular dairy production systems based on grass-clover pastures are becoming increasingly abundant within Danish agriculture. Grass-clover pastures may provide a mitigation option to reduce grassland nitrous oxide (N2O) emissions (Velthof et al. 1998). The objectives of this work was to examine the relationship between N2O emissions and transformations of inorganic N in organically managed grass-clover pastures of different ages. Results from the projec...

Management techniques for the control of Melinis minutiflora P. Beauv. (molasses grass: ten years of research on an invasive grass species in the Brazilian Cerrado

Directory of Open Access Journals (Sweden)

Carlos Romero Martins

2017-09-01

Full Text Available ABSTRACT The invasion of exotic species is considered to be a major threat to the preservation of biodiversity. In the Parque Nacional de Brasília (National Park of Brasília, the invasive Melinis minutiflora (molasses grass occupies more than 10 % of the area of the park. The present, long-term, study compared two treatments of exposure to molasses grass: 1 fire and 2 integrated management (fire + herbicide sprays + manual removal. The aerial biomass of molasses grass in the experimental area initially represented ca. 55 % of the total aerial biomass, a percentage that apparently did not influence native plant species richness at this site. Fire alone was not sufficient to control molasses grass, which attained its pre-treatment biomass values after two years. Integrated management reduced, and maintained, biomass to less than 1 % of its original value after ten years, and maintained this level throughout the study, demonstrating that it is a promising strategy for the recovery of areas invaded by molasses grass in the Cerrado. However, because of the recolonization by molasses grass, long-term monitoring efforts are targeting outbreaks, which would require immediate intervention in order to maintain the native biological diversity of the region.

Nowcasting daily minimum air and grass temperature

Science.gov (United States)

Savage, M. J.

2016-02-01

Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

Effects of conventional and grass-feeding systems on the nutrient composition of beef.

Science.gov (United States)

Leheska, J M; Thompson, L D; Howe, J C; Hentges, E; Boyce, J; Brooks, J C; Shriver, B; Hoover, L; Miller, M F

2008-12-01

The objectives of this study were to determine the nutrient composition of grass-fed beef in the United States for inclusion in the USDA National Nutrient Database for Standard Reference, and to compare the fatty acid composition of grass-fed and conventionally fed (control) beef. Ground beef (GB) and strip steaks (SS) were collected on 3 separate occasions from 15 grass-fed beef producers that represented 13 different states, whereas control beef samples were collected from 3 regions (Ohio, South Dakota, and Texas) of the United States on 3 separate occasions. Concentrations of minerals, choline, vitamin B(12), and thiamine were determined for grass-fed beef samples. Grass-fed GB samples had less Mg, P, and K (P < 0.05), and more Na, Zn, and vitamin B(12) (P < 0.05) than SS samples. Fat color, marbling, and pH were assessed for grass-fed and control SS. Subjective evaluation of the SS indicated that grass-fed beef had fat that was more yellow in color than control beef. Percentages of total fat, total cholesterol, and fatty acids along with trans fatty acids and CLA were determined for grass-fed and control SS and GB. Grass-fed SS had less total fat than control SS (P = 0.001), but both grass-fed and control SS were considered lean, because their total fat content was 4.3% or less. For both GB and SS, grass-fed beef had significantly less (P = 0.001 and P = 0.023, respectively) content of MUFA and a greater content of SFA, n-3 fatty acids, CLA, and trans-vaccenic acid than did the control samples. Concentrations of PUFA, trans fatty acids, n-6 fatty acids, and cholesterol did not differ between grass-fed and control ground beef. Trans-vaccenic acid (trans-11 18:1) made up the greatest concentration of the total trans fats in grass-fed beef, whereas CLA accounted for approximately 15% of the total trans fats. Although the fatty acid composition of grass-fed and conventionally fed beef was different, conclusions on the possible effects of these differences on human

Biogas and Methane Yield from Rye Grass

Directory of Open Access Journals (Sweden)

Tomáš Vítěz

2015-01-01

Full Text Available Biogas production in the Czech Republic has expanded substantially, including marginal regions for maize cultivation. Therefore, there are increasingly sought materials that could partially replace maize silage, as a basic feedstock, while secure both biogas production and its quality.Two samples of rye grass (Lolium multiflorum var. westerwoldicum silage with different solids content 21% and 15% were measured for biogas and methane yield. Rye grass silage with solid content of 15% reached an average specific biogas yield 0.431 m3·kg−1 of organic dry matter and an average specific methane yield 0.249 m3·kg−1 of organic dry matter. Rye grass silage with solid content 21% reached an average specific biogas yield 0.654 m3·kg−1 of organic dry matter and an average specific methane yield 0.399 m3·kg−1 of organic dry matter.

Effects of feeding dairy cows different legume-grass silages on milk phytoestrogen concentration

DEFF Research Database (Denmark)

Höjer, A; Adler, S; Purup, Stig

2012-01-01

interval of legume-grass silage on phytoestrogen intake and milk phytoestrogen concentrations. In one experiment, 15 Swedish Red dairy cows were fed 2- or 3-cut red clover-grass silage, or 2-cut birdsfoot trefoil-grass silage. In a second experiment, 16 Norwegian Red dairy cows were fed short-term ley...... red clover-grass silage diet (1,494μg/kg of milk). Because of the metabolism of biochanin A, genistein, and prunetin, their concentrations in milk and the apparent recovery were low. Coumestrol was detected in only short-term and long-term ley silage mixtures, and its milk concentration was low....... Concentrations of secoisolariciresinol and matairesinol were higher in 2-cut birdsfoot trefoil-grass and long-term ley silage mixtures, those with legume species other than red clover, and the highest grass proportions. The 2-cut birdsfoot trefoil-grass silage diet also resulted in higher enterolactone...

Results from the 5-year SQ grass sublingual immunotherapy tablet asthma prevention (GAP) trial in children with grass pollen allergy

DEFF Research Database (Denmark)

Valovirta, Erkka; Petersen, Thomas H; Piotrowska, Teresa

2018-01-01

BACKGROUND: Allergy immunotherapy targets the immunological cause of allergic rhinoconjunctivitis and allergic asthma and has the potential to alter the natural course of allergic disease. OBJECTIVE: The primary objective was to investigate the effect of the SQ grass sublingual immunotherapy tablet...... compared with placebo on the risk of developing asthma. METHODS: A total of 812 children (5-12 years), with a clinically relevant history of grass pollen allergic rhinoconjunctivitis and no medical history or signs of asthma, were included in the randomized, double-blind, placebo-controlled trial......, comprising 3 years of treatment and 2 years of follow-up. RESULTS: There was no difference in time to onset of asthma, defined by prespecified asthma criteria relying on documented reversible impairment of lung function (primary endpoint). Treatment with the SQ grass sublingual immunotherapy tablet...

A novel method to characterize silica bodies in grasses.

Science.gov (United States)

Dabney, Clemon; Ostergaard, Jason; Watkins, Eric; Chen, Changbin

2016-01-01

The deposition of silicon into epidermal cells of grass species is thought to be an important mechanism that plants use as a defense against pests and environmental stresses. There are a number of techniques available to study the size, density and distribution pattern of silica bodies in grass leaves. However, none of those techniques can provide a high-throughput analysis, especially for a great number of samples. We developed a method utilizing the autofluorescence of silica bodies to investigate their size and distribution, along with the number of carbon inclusions within the silica bodies of perennial grass species Koeleria macrantha. Fluorescence images were analyzed by image software Adobe Photoshop CS5 or ImageJ that remarkably facilitated the quantification of silica bodies in the dry ash. We observed three types of silica bodies or silica body related mineral structures. Silica bodies were detected on both abaxial and adaxial epidermis of K. macrantha leaves, although their sizes, density, and distribution patterns were different. No auto-fluorescence was detected from carbon inclusions. The combination of fluorescence microscopy and image processing software displayed efficient utilization in the identification and quantification of silica bodies in K. macrantha leaf tissues, which should applicable to biological, ecological and geological studies of grasses including forage, turf grasses and cereal crops.

Genetic engineering of grass cell wall polysaccharides for biorefining.

Science.gov (United States)

Bhatia, Rakesh; Gallagher, Joe A; Gomez, Leonardo D; Bosch, Maurice

2017-09-01

Grasses represent an abundant and widespread source of lignocellulosic biomass, which has yet to fulfil its potential as a feedstock for biorefining into renewable and sustainable biofuels and commodity chemicals. The inherent recalcitrance of lignocellulosic materials to deconstruction is the most crucial limitation for the commercial viability and economic feasibility of biomass biorefining. Over the last decade, the targeted genetic engineering of grasses has become more proficient, enabling rational approaches to modify lignocellulose with the aim of making it more amenable to bioconversion. In this review, we provide an overview of transgenic strategies and targets to tailor grass cell wall polysaccharides for biorefining applications. The bioengineering efforts and opportunities summarized here rely primarily on (A) reprogramming gene regulatory networks responsible for the biosynthesis of lignocellulose, (B) remodelling the chemical structure and substitution patterns of cell wall polysaccharides and (C) expressing lignocellulose degrading and/or modifying enzymes in planta. It is anticipated that outputs from the rational engineering of grass cell wall polysaccharides by such strategies could help in realizing an economically sustainable, grass-derived lignocellulose processing industry. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Performance of Vetiver Grass (Vetiveria zizanioides for Phytoremediation of Contaminated Water

Directory of Open Access Journals (Sweden)

Syed Hasan Sharifah Nur Munirah

2017-01-01

Full Text Available In tolerance towards metal uptake, there is a need to evaluate the performance of vetiver grass for metal removal to reduce water impurity. This study was aimed to evaluate contaminant removal by vetiver grass at varying root length and plant density and determine the metal uptake in vetiver plant biomass. Pollutant uptake of vetiver grass was conducted in laboratory experiment and heavy metal analysis was done using acid digestion and Atomic Absorption Spectrometry. Findings indicated that the removal of heavy metal was decreased in seven days of the experiment where iron shows the highest percentage (96%; 0.42 ppm of removal due to iron is highly required for growth of vetiver grass. Removal rate of heavy metals in water by vetiver grass is ranked in the order of Fe>Zn>Pb>Mn>Cu. Results also demonstrated greater removal of heavy metals (Cu, Fe, Mn, Pb, Zn at greater root length and higher density of vetiver grass because it increased the surface area for metal absorption by plant root into vetiver plant from contaminated water. However, findings indicated that accumulation of heavy metals in plant biomass was higher in vetiver shoot than in root due to metal translocation from root to the shoot. Therefore, the findings have shown effective performance of vetiver grass for metal removal in the phytoremediation of contaminated water.

Estimation of grass to cow's milk transfer coefficients for emergency situations

International Nuclear Information System (INIS)

Ujwal, P.; Karunakara, N.; Yashodhara, I.; Rao, Chetan; Kumara, Sudeep; Dileep, B.N.; Ravi, P.M.

2012-01-01

Several studies have been reported on soil to grass equilibrium transfer factors and grass to cow's milk transfer coefficients for 137 Cs for the environs of different nuclear power plants of both India and other parts of the world. In such studies, the activity concentration of 137 Cs is measured in grass collected from different places. Cow's milk samples are collected from nearby localities or from milk dairies and analyzed for 137 Cs and the grass to cow's milk transfer coefficient is estimated. In situation where 137 Cs is not present in measurable activity concentrations, its stable counterpart (Cs) is measured for the estimation of transfer coefficients. These transfer coefficient values are generally used in theoretical models to estimate the dose to the population for hypothetical situation of emergency. It should be noted that the transfer coefficients obtained for equilibrium conditions may not be totally applicable for emergency situation. However, studies aimed at evaluating transfer coefficients for emergency situations are sparse because nuclear power plants do not release 137 Cs during normal operating situations and therefore simulating situation of emergency release is not possible. Hence, the only method to estimate the grass to milk transfer coefficient for emergency situation is to spike the grass with small quantity of stable Cs. This paper reports the results of grass to milk transfer coefficients for stable isotope of Cesium (Cs) for emergency situation

Soil nitrogen mineralization not affected by grass species traits

Science.gov (United States)

Maged Ikram Nosshi; Jack Butler; M. J. Trlica

2007-01-01

Species N use traits was evaluated as a mechanism whereby Bromus inermis (Bromus), an established invasive, might alter soil N supply in a Northern mixed-grass prairie. We compared soils under stands of Bromus with those from three representative native grasses of different litter C/N: Andropogon...

Factors affecting palatability of four submerged macrophytes for grass carp Ctenopharyngodon idella.

Science.gov (United States)

Sun, Jian; Wang, Long; Ma, Lin; Min, Fenli; Huang, Tao; Zhang, Yi; Wu, Zhenbin; He, Feng

2017-12-01

Grass carp can weaken the growth and reproductive capacity of submerged macrophytes by consuming valuable tissues, but factors affecting palatability of submerged macrophytes for grass carp rarely are considered. In this study, relative consumption rate of grass carp with regard to submerged macrophytes was in the following order: Hydrilla verticillata > Vallisneria natans > Ceratophyllum demersum > Myriophyllum spicatum. Firmness of macrophytes was in the following order: M. spicatum > C. demersum > H. verticillata = V. natans, whereas shear force was M. spicatum > C. demersum > H. verticillata > V. natans. After crude extracts of M. spicatum were combined with H. verticillata, grass carp fed on fewer macrophyte pellets that contained more plant secondary metabolites (PSMs). This indicated that structure and PSMs affected palatability of macrophytes.PSMs do not contribute to reduction in palatability through inhibition of intestinal proteinases activity, but they can cause a decrease in the abundance of Exiguobacterium, Acinetobacter-yielding proteases, lipases, and cellulose activity, which in turn can weaken the metabolic capacity of grass carp and adversely affect their growth. Thus, the disadvantages to the growth and development of grass carp caused by PSMs may drive grass carp to feed on palatable submerged macrophytes with lower PSMs.

The design and development of GRASS file reservation system

International Nuclear Information System (INIS)

Huang Qiulan; Zhu Suijiang; Cheng Yaodong; Chen Gang

2010-01-01

GFRS (GRASS File Reservation System) is designed to improve the file access performance of GRASS (Grid-enabled Advanced Storage System) which is a Hierarchical Storage Management (HSM) system developed at Computing Center, Institute of High Energy Physics. GRASS can provide massive storage management and data migration, but the data migration policy is simply based factors such as pool water level, the intervals for migration and so on, so it is short of precise control over files. As for that, we design GFRS to implement user-based file reservation which is to reserve and keep the required files on disks for High Energy physicists. CFRS can improve file access speed for users by avoiding migrating frequently accessed files to tapes. In this paper we first give a brief introduction of GRASS system and then detailed architecture and implementation of GFRS. Experiments results from GFRS have shown good performance and a simple analysis is made based on it. (authors)

Designing a New Raster Sub-System for GRASS-7

Directory of Open Access Journals (Sweden)

Martin Hruby

2012-03-01

Full Text Available The paper deals with a design of a new raster sub-system intended for modern GIS systems open for client and server operation, database connection and strong application interface (API. Motivation for such a design comes from the current state of API working in GRASS 6. If found attractive, the here presented design and its implementation (referred as RG7 may be integrated to the future new generation of the GRASS Geographical Information System version 7-8. The paper describes in details the concept of raster tiling, computer storage of rasters and basic raster access procedures. Finally, the paper gives a simple benchmarking experiment of random read access to raster files imported from the Spearfish dataset. The experiment compares the early implementation of RG7 with the current implementation of rasters in GRASS 6. As the result, the experiment shows the RG7 to be significantly faster than GRASS in random read access to large raster files.

Comparative growth analysis of cool- and warm-season grasses in a cool-temperate environment

International Nuclear Information System (INIS)

Belesky, D.P.; Fedders, J.M.

1995-01-01

Using both cool-season (C3) and warm-season (C4) species is a viable means of optimizing herbage productivity over varying climatic conditions in temperate environments. Despite well-documented differences in water, N, and radiation use, no consistent evidence demonstrates productivity differences among C3 and C4 perennial grass species under identical management. A field study was conducted to determine relative growth rates (RGR), nitrogen productivity (NP), and mean radiation productivity (RP) (dry matter production as a function of incident radiation) of cool- and warm-season grasses managed identically. Results were used to identify management practices thd could lead to optimal productivity in combinations or mixtures of cool- and warm-season grasses. Dry matter yields of warm-season grasses equaled or surpassed those of cool-season grasses, despite a 40% shorter growth interval. Certain cool- and warm-season grasses appear to be suitable for use in mixtures, based on distribution of herbage production; however, actual compatibility may be altered by defoliation management. Relative growth rates varied among years and were about 40% lower for canopies clipped to a 10-cm residue height each time 20-cm of growth accumulated compared with other treatments. The RGR of warm-season grasses was twice that of cool-season grasses Nitrogen productivity (g DM g-1 N d -1) and mean radiation productivity (g DM MJ-1) for warm-season grasses was also more than twice that of cool-season grasses. Radiation productivity of cool-season grasses was dependent on N, while this was not always the case for warm-season grasses. The superior production capability of certain warm-season compared with cool-season grasses in a cool-temperate environment can be sustained under a range of defoliation treatments and demonstrates suitability for use in frequently defoliated situations

EBIPM | Finding the Tools to Manage Invasive Annual Grasses

Science.gov (United States)

management decisions for a given landscape based on ecological principles. Take a look at our video " Grass Management How much could prevention save you? Guidelines to Implement EBIPM Weed Prevention Areas Grass Facts/ID The EBIPM Model Crooked River Weed Management Area Guide Tools for Educators EBIPM High

TRANSPORT OUTSOURCING AND TRANSPORT COLLABORATION RELATIONSHIP - THE RISK HEDGING PERSPECTIVE

Directory of Open Access Journals (Sweden)

Đurđica M. Stojanović

2015-04-01

Full Text Available Although transport outsourcing decision-making and collaborative transport management (CTM have been “hot topics” for years, their links are still not thoroughly explored. The purpose of this paper is to contribute to a better understanding of the relationship between them. In particular, we focus on the conflicting and complementary features of these concepts with regard to their capability to hedge against transport outsourcing-related risks. Transport outsourcing is often a tool for transferring part of the demand risks from the primary parties in supply chains to transport service providers. However, new relationships introduce some new risks - outsourcing contract risks. It is important to identify, estimate and compare such kinds of risks. Transport collaboration may decrease both the demand risks and the outsourcing contract risks, although the relationship with the latter is more complex. It is used an exploratory research based on a combination of a literature review and empirical examples.

Designing hybrid grass genomes to control runoff generation

Science.gov (United States)

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

2010-12-01

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

DESIGN OF GRASS BRIQUETTE MACHINE

African Journals Online (AJOL)

user

E-mail addresses: 1 mike.ajieh@gmail.com, 2 dracigboanugo@yahoo.com, ... machine design was considered for processing biomass of grass origin. The machine operations include pulverization, compaction and extrusion of the briquettes.

Grass and weed killer poisoning

Science.gov (United States)

... medlineplus.gov/ency/article/002838.htm Grass and weed killer poisoning To use the sharing features on this page, please enable JavaScript. Many weed killers contain dangerous chemicals that are harmful if ...

Role of carbohydrate metabolism in grass tetany

Energy Technology Data Exchange (ETDEWEB)

Miller, J.K.; Madsen, F.C.; Lentz, D.E.; Hansard, S.L.

1977-01-01

Clinical hypomagnesemia is confined primarily to beef cattle in the United States but also occurs in dairy cattle in other countries, probably due to different management practices. During periods when grass tetany is likely, early vegetative temperate zone grasses are usually low in total readily available carbohydrates and magnesium but high in potassium and nitrogen. The tetany syndrome may include hypoglycemia and ketosis, suggesting an imbalance in intermediary energy metabolism. Many enzyme systems critical to cellular metabolism, including those which hydrolyze and transfer phosphate groups, are activated by Mg. Thus, by inference, Mg is required for normal glucose utilization, fat, protein, nucleic acid and coenzyme synthesis, muscle contraction, methyl group transfer, and sulfate, acetate, and formate activation. Numerous clinical and experimental studies suggest an intimate relationship between metabolism of Mg and that of carbohydrate, glucagon, and insulin. The objective is to review this literature and suggest ways in which these relationships might contribute to a chain of events leading to grass tetany.

IgE-binding capacity of recombinant timothy grass (Phleum pratense) pollen allergens

NARCIS (Netherlands)

Laffer, S.; Vrtala, S.; Duchêne, M.; van Ree, R.; Kraft, D.; Scheiner, O.; Valenta, R.

1994-01-01

A panel of 60 cDNA clones coding for IgE-binding proteins from timothy grass pollen was immunocharacterized with sera from 30 patients allergic to grass pollen and antibodies raised against natural grass pollen allergens. In the cases of five representative patients in whom the IgE reactivity

Status of exotic grasses and grass-like vegetation and potential impacts on wildlife in New England

Science.gov (United States)

DeStefano, Stephen

2013-01-01

The Northeastern section of the United States, known as New England, has seen vast changes in land cover and human population over the past 3 centuries. Much of the region is forested; grasslands and other open-land cover types are less common, but provide habitat for many species that are currently declining in abundance and distribution. New England also consists of some of the most densely populated and developed states in the country. The origin, distribution, and spread of exotic species are highly correlated with human development. As such, exotics are common throughout much of New England, including several species of graminoids (grasses and grass-like plants such as sedges and rushes). Several of the more invasive grass species can form expansive dense mats that exclude native plants, alter ecosystem structure and functions, and are perceived to provide little-to-no value as wildlife food or cover. Although little research has been conducted on direct impacts of exotic graminoids on wildlife populations in New England, several studies on the common reed (Phragmites australis) in salt marshes have shown this species to have variable effects as cover for birds and other wildlife, depending on the distribution of the plant (e.g., patches and borders of reeds are used more by wildlife than expansive densely growing stands). Direct impacts of other grasses on wildlife populations are largely unknown. However, many of the invasive graminoid species that are present in New England have the capability of outcompeting native plants and thereby potentially affecting associated fauna. Preservation, protection, and restoration of grassland and open-land cover types are complex but necessary challenges in the region to maintain biological and genetic diversity of grassland, wetland, and other open-land obligate species.

Growth and nutritional evaluation of napier grass hybrids as forage for ruminants

Directory of Open Access Journals (Sweden)

Brian Turano

2016-09-01

Full Text Available Napier grass is a perennial, tropical C-4 grass that can produce large amounts of forage. However, low temperatures and drought stress limit its productivity and nutritive value as a forage. To overcome these limitations, pearl millet × napier grass hybrids (PMN were developed. It was hypothesized that PMN hybrids were more drought-tolerant, produced higher yields, and had higher nutritive value than napier grass varieties. The yield and nutritive value of 4 napier grass varieties (Bana grass, Mott, MB4 and N51 and 4 PMN hybrids (PMN2, PMN3, 5344 and 4604 were determined with or without irrigation in a strip plot design in Hawaii. Hybrid PMN3 outperformed napier grass varieties and the other hybrids for yield, while 5344 showed higher nutritional content and digestibility than most other grasses. Dry matter yields during the 110-day study period ranged from 10.3 to 32.1 t/ha without irrigation and 19.6 to 55.8 t/ha with irrigation, indicating that moisture stress was limiting performance in raingrown pastures. Only hybrids PMN3 and PMN2 and variety MB4 showed significant growth responses to irrigation. Further work is needed to evaluate the hybrids in a range of environments over much longer periods to determine if these preliminary results can be reproduced over the long term. Similarly, feeding studies with animals are needed to determine if the in vitro data for digestibility are reflected in superior performance for the promising hybrids.Keywords: Biomass, cattle, in vitro digestion, nutrient content, Pennisetum, tropical grasses.DOI: 10.17138/TGFT(4168-178

Evaluation of molecular basis of cross reactivity between rye and Bermuda grass pollen allergens.

Science.gov (United States)

Tiwari, Ruby; Bhalla, Prem L; Singh, Mohan B

2009-12-01

Allergenic cross reactivity between the members of the Pooids (Lolium perenne, Phleum pratense, and Poa pratensis) and Chloridoids (Cynodon dactylon and Paspalum notatum) is well established. Studies using crude extracts in the past have demonstrated limited cross reactivity between the Pooids and the Chloridoids suggesting separate diagnosis and therapy. However, little is known regarding the molecular basis for the limited cross reactivity observed between the 2 groups of grasses. The present study was undertaken to gain insights into the molecular basis of cross allergenicity between the major allergens from rye and Bermuda grass pollens. Immunoblot inhibition tests were carried out to determine the specificity of the proteins involved in cross reactivity. Crude pollen extract and bacterially expressed and purified recombinant Lol p 1and Lol p 5 from rye grass were subjected to cross inhibition experiments with crude and purified recombinant Cyn d 1 from Bermuda grass using sera from patients allergic to rye grass pollen. The immunoblot inhibition studies revealed a high degree of cross inhibition between the group 1 allergens. In contrast, a complete lack of inhibition was observed between Bermuda grass group 1 allergen rCyn d 1, and rye grass group 5 allergen rLol p 5. Crude rye grass extract strongly inhibited IgE reactivity to Bermuda grass, whereas crude Bermuda grass pollen extract showed a weaker inhibition. Our data suggests that a possible explanation for the limited cross reactivity between the Pooids and Chloridoids may, in part, be due to the absence of group 5 allergen from Chloridoid grasses. This approach of using purified proteins may be applied to better characterize the cross allergenicity patterns between different grass pollen allergens.

Grass defoliation affecting survival and growth of seedlings of ...

African Journals Online (AJOL)

Two experiments were conducted, one in the field and the other in the greenhouse, to investigate the effects of the intensity and frequency of grass defoliation on the survival and growth of Acacia karroo seedlings. In the greenhouse, seedlings growing with heavily clipped grasses had higher biomass production than those ...

Analysis of Some Heavy Metals in Grass ( Paspalum Orbiculare ...

African Journals Online (AJOL)

The increased deposition of trace metals from vehicle exhausts on plants has raised concerns about the risks of the quality of food consumed by humans since the heavy metals emitted through the exhaust by vehicles can enter food chain through deposition on grass grazed by animals. Grass (Paspalum Orbiculare) and ...

Whole rice bran for beef heifers raised on alexander grass pasture

Directory of Open Access Journals (Sweden)

P. R. Salvador

2016-09-01

Full Text Available The objective of this study was to evaluate the development of beef heifers exclusively fed alexander grass (Urochloa plantaginea (Link Hitch or alexander grass and whole rice meal as supplement offered from Monday to Friday. The experimental design was completely randomized, with repeated measures over time, and consisted of two treatments and three replications of area. Heifers receiving whole rice meal exhibited higher average daily gain after day 42 of pasture use and a 21% higher body weight at the end of the grazing period. The stocking rate, weight gain per area, hip height, weight-height ratio, and body condition score were similar for heifers exclusively fed alexander grass and alexander grass plus rice bran. Beef heifers raised exclusively on alexander grass from 15 to 18 months of age reached adequate body development, reproductive tract score (4.22 points and pelvic area (206.3 cm² to be bred at 18-20 months of age.

Toward Genomics-Based Breeding in C3 Cool-Season Perennial Grasses

Science.gov (United States)

Talukder, Shyamal K.; Saha, Malay C.

2017-01-01

Most important food and feed crops in the world belong to the C3 grass family. The future of food security is highly reliant on achieving genetic gains of those grasses. Conventional breeding methods have already reached a plateau for improving major crops. Genomics tools and resources have opened an avenue to explore genome-wide variability and make use of the variation for enhancing genetic gains in breeding programs. Major C3 annual cereal breeding programs are well equipped with genomic tools; however, genomic research of C3 cool-season perennial grasses is lagging behind. In this review, we discuss the currently available genomics tools and approaches useful for C3 cool-season perennial grass breeding. Along with a general review, we emphasize the discussion focusing on forage grasses that were considered orphan and have little or no genetic information available. Transcriptome sequencing and genotype-by-sequencing technology for genome-wide marker detection using next-generation sequencing (NGS) are very promising as genomics tools. Most C3 cool-season perennial grass members have no prior genetic information; thus NGS technology will enhance collinear study with other C3 model grasses like Brachypodium and rice. Transcriptomics data can be used for identification of functional genes and molecular markers, i.e., polymorphism markers and simple sequence repeats (SSRs). Genome-wide association study with NGS-based markers will facilitate marker identification for marker-assisted selection. With limited genetic information, genomic selection holds great promise to breeders for attaining maximum genetic gain of the cool-season C3 perennial grasses. Application of all these tools can ensure better genetic gains, reduce length of selection cycles, and facilitate cultivar development to meet the future demand for food and fodder. PMID:28798766

Toward Genomics-Based Breeding in C3 Cool-Season Perennial Grasses

Directory of Open Access Journals (Sweden)

Shyamal K. Talukder

2017-07-01

Full Text Available Most important food and feed crops in the world belong to the C3 grass family. The future of food security is highly reliant on achieving genetic gains of those grasses. Conventional breeding methods have already reached a plateau for improving major crops. Genomics tools and resources have opened an avenue to explore genome-wide variability and make use of the variation for enhancing genetic gains in breeding programs. Major C3 annual cereal breeding programs are well equipped with genomic tools; however, genomic research of C3 cool-season perennial grasses is lagging behind. In this review, we discuss the currently available genomics tools and approaches useful for C3 cool-season perennial grass breeding. Along with a general review, we emphasize the discussion focusing on forage grasses that were considered orphan and have little or no genetic information available. Transcriptome sequencing and genotype-by-sequencing technology for genome-wide marker detection using next-generation sequencing (NGS are very promising as genomics tools. Most C3 cool-season perennial grass members have no prior genetic information; thus NGS technology will enhance collinear study with other C3 model grasses like Brachypodium and rice. Transcriptomics data can be used for identification of functional genes and molecular markers, i.e., polymorphism markers and simple sequence repeats (SSRs. Genome-wide association study with NGS-based markers will facilitate marker identification for marker-assisted selection. With limited genetic information, genomic selection holds great promise to breeders for attaining maximum genetic gain of the cool-season C3 perennial grasses. Application of all these tools can ensure better genetic gains, reduce length of selection cycles, and facilitate cultivar development to meet the future demand for food and fodder.

Modelling of excess noise attnuation by grass and forest | Onuu ...

African Journals Online (AJOL)

, guinea grass (panicum maximum) and forest which comprises iroko (milicia ezcelea) and white afara (terminalia superba) trees in the ratio of 2:1 approximately. Excess noise attenuation spectra have been plotted for the grass and forest for ...

Effect of grass species on NDF ruminal degradability and ...

African Journals Online (AJOL)

uzivatel

Abstract. The objective of this study was to compare the ruminal degradability of neutral detergent fibre (NDF) .... Felina were evaluated in the present study. The grass was harvested from the primary growth of monocultured grasses on 19 and 26 May of 2004 and 27 May and 10 ...... Nutritional Ecology of the Ruminant.

Defoliation effects of perennial grasses – continuing confusion | DL ...

African Journals Online (AJOL)

Although an adequate knowledge of growth patterns and defoliation effects in perennial grasses is a prerequisite for the rational use of veld and pastures for animal production, our knowledge of this subject is far from adequate. The results of various physiological and clipping studies on tropical and sub-tropical grasses are ...

Seed production and establishment of western Oregon native grasses

Science.gov (United States)

Dale C. Darris

2005-01-01

It is well understood that native grasses are ecologically important and provide numerous benefits. However, unfavorable economics, low seed yields for some species, genetic issues, and a lack of experience behind the production and establishment of most western Oregon native grasses remain significant impediments for their expanded use. By necessity, adaptation of...

Grass as a C booster for manure-biogas in Estonia

DEFF Research Database (Denmark)

Pehme, Sirli; Hamelin, Lorie; Veromann, Eve

2014-01-01

The aim of this study was to assess the environmental consequences of using grass (from both unused and cultivated boreal grasslands) as a co-substrate to dairy cow manure for biogas production. Environmental impact categories assessed were global warming, acidification and nutrient enrichment...... (distinguishing between N and P). Scenarios studied were: traditional management of dairy cow manure, monodigestion of manure, manure co-digestion with reed canary grass and manure co-digestion with residual grass from semi-natural grasslands. The latter scenario showed the best environmental performance...... for the global warming category, for other categories it did not show clear benefits. Using reed canary grass specially produced for biogas purpose resulted in a climate change impact just as big as the reference manure management, mainly as a result of indirect land use changes. Increased impacts also occurred...

Reduction in clover-grass yield caused by different traffic intensities

DEFF Research Database (Denmark)

Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian

Different traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16...... close to the north, south and east border of the field. No significant interactions were found between the timing of crop and soil damage as affected by wheel load and tire pressure. However, at specific times, there was a significant effect of wheel load and secondary by the tire pressure. At all...... measurement times, the yield was lower using a wheel load of 4745 kg than for a wheel load of 2865 kg.     Key words (for Electronic Reference Library) Traffic intensities, tire load/pressure, clover/grass, yield loss, ...

Napier Grass and Legume Silage for Smallholder Farmers in Coastal Kenya

International Nuclear Information System (INIS)

Muinga, R.W.; Mambo, L.C.; Bimbuzi, S.

1999-01-01

Inadequate feed during the dry season is a major cause of low dairy productivity in Kenya. Napier grass is grown by smallholder dairy farmers due to its high biomass yield especially during the rainy season when it can be ensiled to ensure feed available in the dry season.The objective of the study was to determine the silage quality of mixtures of Napier grass and Legume forages. Maize bran was used as the main source of readily available carbohydrates replacing molasses. The mixtures were compared to the conventional Napier grass/legume has higher nutritive value than silage made from Napier grass only and that maize bran could replace molasses as a source of readily available carbohydrates

Analyzing rasters, vectors and time series using new Python interfaces in GRASS GIS 7

Science.gov (United States)

Petras, Vaclav; Petrasova, Anna; Chemin, Yann; Zambelli, Pietro; Landa, Martin; Gebbert, Sören; Neteler, Markus; Löwe, Peter

2015-04-01

GRASS GIS 7 is a free and open source GIS software developed and used by many scientists (Neteler et al., 2012). While some users of GRASS GIS prefer its graphical user interface, significant part of the scientific community takes advantage of various scripting and programing interfaces offered by GRASS GIS to develop new models and algorithms. Here we will present different interfaces added to GRASS GIS 7 and available in Python, a popular programming language and environment in geosciences. These Python interfaces are designed to satisfy the needs of scientists and programmers under various circumstances. PyGRASS (Zambelli et al., 2013) is a new object-oriented interface to GRASS GIS modules and libraries. The GRASS GIS libraries are implemented in C to ensure maximum performance and the PyGRASS interface provides an intuitive, pythonic access to their functionality. GRASS GIS Python scripting library is another way of accessing GRASS GIS modules. It combines the simplicity of Bash and the efficiency of the Python syntax. When full access to all low-level and advanced functions and structures from GRASS GIS library is required, Python programmers can use an interface based on the Python ctypes package. Ctypes interface provides complete, direct access to all functionality as it would be available to C programmers. GRASS GIS provides specialized Python library for managing and analyzing spatio-temporal data (Gebbert and Pebesma, 2014). The temporal library introduces space time datasets representing time series of raster, 3D raster or vector maps and allows users to combine various spatio-temporal operations including queries, aggregation, sampling or the analysis of spatio-temporal topology. We will also discuss the advantages of implementing scientific algorithm as a GRASS GIS module and we will show how to write such module in Python. To facilitate the development of the module, GRASS GIS provides a Python library for testing (Petras and Gebbert, 2014) which

Biotechnological application of sustainable biogas production through dry anaerobic digestion of Napier grass.

Science.gov (United States)

Dussadee, Natthawud; Ramaraj, Rameshprabu; Cheunbarn, Tapana

2017-05-01

Napier grass (Pennisetum purpureum), represents an interesting substrate for biogas production. The research project evaluated biogas potential production from dry anaerobic digestion of Napier grass using batch experiment. To enhance the biogas production from ensiled Napier grass, thermal and alkaline pre-treatments were performed in batch mode. Alkali hydrolysis of Napier grass was performed prior to batch dry anaerobic digestion at three different mild concentrations of sodium hydroxide (NaOH). The study results confirmed that NaOH pretreated sample produced high yield of biogas than untreated (raw) and hot water pretreated samples. Napier grass was used as the mono-substrate. The biogas composition of carbon dioxide (30.10%), methane (63.50%) and 5 ppm of H 2 S was estimated from the biogas. Therefore, fast-growing, high-yielding and organic matter-enriched of Napier grass was promising energy crop for biogas production.

Effect of short-duration overnight cattle kraaling on grass production ...

African Journals Online (AJOL)

... grass species, such as Urochloa mosambicensis and Panicum maximum, were more abundant in abandoned kraal sites than the surrounding vegetation. We conclude that shortduration overnight cattle kraaling improves grass quality and biomass. Keywords: biomass, crude protein, diversity, fibre, nutrient hotspots ...

Conceptual model for reinforced grass on inner dike slopes

NARCIS (Netherlands)

Verhagen, H.J.; ComCoast

2005-01-01

A desk study has been carried out in order to develop a conceptual model for the erosion of inner dike slopes with reinforced grass cover. Based on the results the following can be concluded: The presence of a geosynthetic in a grass slope can be taken into account in the EPM method by increasing

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

Science.gov (United States)

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

2014-02-19

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

Microbiological Quality of Panicum maximum Grass Silage with Addition of Lactobacillus sp. as Starter

Science.gov (United States)

Sumarsih, S.; Sulistiyanto, B.; Utama, C. S.

2018-02-01

The aim of the research was to evaluate microbiological quality of Panicum maximum grass silage with addition Lactobacillus sp as starter. The completely randomized design was been used on this research with 4 treaments and 3 replications. The treatments were P0 ( Panicum maximum grass silage without addition Lactobacillus sp ), P1 ( Panicum maximum grass silage with 2% addition Lactobacillus sp), P2 (Panicum maximum grass silage with 4% addition Lactobacillus sp) and P3 (Panicum maximum grass silage with 6% addition Lactobacillus sp).The parameters were microbial populations of Panicum maximum grass silage (total lactic acid bacteria, total bacteria, total fungi, and Coliform bacteria. The data obtained were analyzed variance (ANOVA) and further tests performed Duncan’s Multiple Areas. The population of lactic acid bacteria was higher (PMicrobiological quality of Panicum maximum grass silage with addition Lactobacillus sp was better than no addition Lactobacillus sp.

Cosmogenic Be-7 in grass of Maamora site

International Nuclear Information System (INIS)

El-khoukhi, T.; Fidah, M.; Oublaid, B.

1994-01-01

Be-7 is one of the radionuclides produced by the nuclear reactions of protons and alpha particulates of galactic and solar cosmic rays as well as the secondary neutrons produced during those reactions. it is submitted, as soon as it is produced, to the physical and chemical laws of the environment, such as air motions or the fixing to the atmospheric aerosols. In the framework of environmental radioactivity monitoring programme of Maamora site (Morocco), samples of grass were collected, prepared and analyzed using gamma spectrometry. The preparation consists of drying and ashing the grass. The detector used is coaxial Ge HP with 20% efficiency. Samples were counted for more than 50000 s. The activity of Be-7 calculated for samples collected in 10 km around Maamora site varies between 4 and 20 Bq/g of ashed grass. 3 refs. (author)

Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

Directory of Open Access Journals (Sweden)

Xiaolan Rao

2017-05-01

Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

Analysis and Accounting of Hedging of a Net Investment in a Foreign Operation Process in the concept of Turkish Accounting Standards

Directory of Open Access Journals (Sweden)

Veli Öztürk

2013-09-01

Full Text Available In recent years, in line with developments in the financial markets, financial instruments developed rapidly. As a result of this development, how to classify financial instruments, recognition of these principles has become important. As a result of the every day increase in types of financial instruments, financial risks have emerged. Especially after the end of the Bretton Woods system that based on fixed exchange rates in 1970’s, entities faced the financial risk. IAS 39 gathered financial risks faced by businesses in the financial markets in three groups. These risks are risk arising from financial instruments at fair value and risk arising from cash flows and risk arising from the net investment in a foreign operation. Preventing from the risk arising from the net investment in a foreign operation hedge that composes the subject of this study and also one type of prevention from financial risk, is explained in Turkish Accounting Standards TAS 21 and TAS 39. The implementation section of this study, one of the varieties of hedging, hedge accounting is an example of a net investment in a foreign operation. Example implementation is divided into three sections. In the first part, the increase and decreases at the exchange rates that arised from the position in which the entity made investment does not make forward contracts arised exchange rates are shown. In the second part of our application, the accounting records related to forward contract made for preventing from net investment risk are shown, and how the forward contract prevent the entity from net investment risk is explained. In the final part of the implementation, the disposal of the net investment in a foreign country and it’s results are shown.

The combined effect of fertiliser nitrogen and phosphorus on herbage yield and change in soil nutrients of a grass/clover and grass-only sward

NARCIS (Netherlands)

Schils, R.L.M.; Snijders, P.J.M.

2004-01-01

The combined effect of reduced nitrogen ( N ) and phosphorus ( P ) application on the production of grass- only and grass/ clover swards was studied in a five- year cutting experiment on a marine clay soil, established on newly sown swards. Furthermore, changes in soil N, P and carbon ( C ) were

A capillary pumping device utilizing super-hydrophobic silicon grass

International Nuclear Information System (INIS)

Kung, Chun-Fei; Chang, Chien-Cheng; Chu, Chin-Chou

2011-01-01

In this study, we show that a compact silicon grass surface can be generated by utilizing the induced coupled plasma method with suitably chosen fabrication parameters. This super-hydrophobic structure suspends deionized water on top of the grass and keeps the contact angle at around 153°. The silicon grass is used to improve the driving efficiency of a capillary pumping micro-duct (without sidewalls), which is completely defined by a bottom hydrophilic stripe (adjacent to a Teflon substrate) and a fully top-covered hydrophobic Teflon surface which is coated on a glass substrate. The channel has a height of 3 µm and a width of 100 µm. In this work, the Teflon substrate is replaced with the silicon grass surface. When the fluid is flowing through the micro-duct on the stripe, the interface between the silicon grass and the hydrophilic stripe forms a stable air cushion barrier to the fluid, thus effectively reducing the frictional force. By changing only the interface with this replacement, we demonstrate that the average measured velocities of the new design show improvements of 21% and 17% in the driving efficiency over the original design for transporting deionized water and human blood, respectively. It is also shown that the measured data of the present design are closer to the values predicted by a theoretical analysis which relates the flow velocity to the contact angles, surface tension and fluid viscosity

Tree-grass interactions in savannas

CSIR Research Space (South Africa)

Scholes, RJ

1997-01-01

Full Text Available Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign...

Remote sensing of St. Augustine Decline (SAD) disease. [spectral reflectance of healthy and diseased grass

Science.gov (United States)

Odle, W. C.

1976-01-01

Laboratory and field spectral reflectance measurements of healthy and infected St. Augustine grass were made using several different instruments. Spectral differences between healthy and infected grass occured in the visible and near infrared regions. Multiband and color infrared photographs were taken of healthy and diseased turf from ground-based platforms and low altitude aircraft. Qualitative (density slicing) and quantitative (transmission densitometry) analyses revealed distinct tonal differences between healthy and St. Augustine disease (SAD) infected grass. Similar experiments are described for determining if healthy and diseased grass can be distinguished from waterstressed grass and grass deficient in either nitrogen or iron.

Diet Affects Muscle Quality and Growth Traits of Grass Carp (Ctenopharyngodon idellus): A Comparison Between Grass and Artificial Feed.

Science.gov (United States)

Zhao, Honghao; Xia, Jianguo; Zhang, Xi; He, Xugang; Li, Li; Tang, Rong; Chi, Wei; Li, Dapeng

2018-01-01

Fish muscle, the main edible parts with high protein level and low fat level, is consumed worldwide. Diet contributes greatly to fish growth performance and muscle quality. In order to elucidate the correlation between diet and muscle quality, the same batch of juvenile grass carp ( Ctenopharyngodon idellus ) were divided into two groups and fed with either grass ( Lolium perenne, Euphrasia pectinata and Sorghum sudanense ) or artificial feed, respectively. However, the different two diets didn't result in significant differences in all the detected water quality parameters (e.g., Tm, pH, DO, NH 3 /[Formula: see text]-N, [Formula: see text]-N, [Formula: see text], TN, TP, and TOC) between the two experimental groups. After a 4-month culture period, various indexes and expression of myogenic regulatory factor (MRFs) and their related genes were tested. The weight gain of the fish fed with artificial feed (AFG) was nearly 40% higher than the fish fed with grass (GFG). Significantly higher alkaline phosphatase, total cholestrol, high density cholestrol and total protein were detected in GFG as compared to AFG. GFG also showed increased hardness, resilience and shear force in texture profile analysis, with significantly bigger and compact muscle fibers in histologic slices. The fat accumulation was most serious in the abdomen muscle of AFG. Additionally, the expression levels of MyoG, MyoD, IGF - 1 , and MSTNs were higher, whereas Myf - 5, MRF4 , and IGF -2 were lower in most positional muscles of GFG as compared to AFG. Overall, these results suggested that feeding grass could promote muscle growth and development by stimulating muscle fiber hypertrophy, as well as significantly enhance the expression of CoL1A s. Feeding C. idellus with grass could also improve flesh quality by improving muscle characteristics, enhancing the production of collagen, meanthile, reducing fat accumulation and moisture in muscle, but at the cost of a slower growth.

Diet Affects Muscle Quality and Growth Traits of Grass Carp (Ctenopharyngodon idellus: A Comparison Between Grass and Artificial Feed

Directory of Open Access Journals (Sweden)

Honghao Zhao

2018-03-01

Full Text Available Fish muscle, the main edible parts with high protein level and low fat level, is consumed worldwide. Diet contributes greatly to fish growth performance and muscle quality. In order to elucidate the correlation between diet and muscle quality, the same batch of juvenile grass carp (Ctenopharyngodon idellus were divided into two groups and fed with either grass (Lolium perenne, Euphrasia pectinata and Sorghum sudanense or artificial feed, respectively. However, the different two diets didn't result in significant differences in all the detected water quality parameters (e.g., Tm, pH, DO, NH3/NH4+-N, NO3--N, NO2-, TN, TP, and TOC between the two experimental groups. After a 4-month culture period, various indexes and expression of myogenic regulatory factor (MRFs and their related genes were tested. The weight gain of the fish fed with artificial feed (AFG was nearly 40% higher than the fish fed with grass (GFG. Significantly higher alkaline phosphatase, total cholestrol, high density cholestrol and total protein were detected in GFG as compared to AFG. GFG also showed increased hardness, resilience and shear force in texture profile analysis, with significantly bigger and compact muscle fibers in histologic slices. The fat accumulation was most serious in the abdomen muscle of AFG. Additionally, the expression levels of MyoG, MyoD, IGF-1, and MSTNs were higher, whereas Myf-5, MRF4, and IGF-2 were lower in most positional muscles of GFG as compared to AFG. Overall, these results suggested that feeding grass could promote muscle growth and development by stimulating muscle fiber hypertrophy, as well as significantly enhance the expression of CoL1As. Feeding C. idellus with grass could also improve flesh quality by improving muscle characteristics, enhancing the production of collagen, meanthile, reducing fat accumulation and moisture in muscle, but at the cost of a slower growth.

Insects traversing grass-like vertical compliant beams

Science.gov (United States)

Li, Chen; Fearing, Ronald; Full, Robert

2014-03-01

Small running animals encounter many challenging terrains. These terrains can be filled with 3D, multi-component obstacles. Here, we study cockroaches (Blaberus discoidalis) moving through grass-like vertical compliant beams during escape. We created an apparatus to control and vary geometric parameters and mechanical properties of model grass including height, width, thickness, lateral and fore-aft spacings, angle, number of layers, stiffness, and damping. We observed a suite of novel locomotor behaviors not previously described on simpler 2D ground. When model grass height was >2 × body length and lateral spacing was test our hypothesis, we modified body shape by adding either a rectangular or an oval plate onto its dorsal surface, and found that P dropped by an order of magnitude and t more than doubled. Upon removal of either plate, both P and t recovered. Locomotor kinematics and geometry effectively coupled to terrain properties enables negotiation of 3D, multi-component obstacles, and provides inspiration for small robots to navigate such terrain with minimal sensing and control.

Hand-arm vibration disorder among grass-cutter workers in Malaysia.

Science.gov (United States)

Azmir, Nor Azali; Ghazali, Mohd Imran; Yahya, Musli Nizam; Ali, Mohamad Hanafi

2016-09-01

Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand-arm vibration syndrome (HAVS). A cross-sectional study was carried out using an adopted HAVS questionnaire on hand-arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low-moderate exposure risk groups were evaluated. There were positive HAVS symptoms relationships between the low-moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand-arm vibration, and it seemed to be related to the finger blanching and numbness. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers.

Role of ammonia and biogenic amines in intake of grass silage by ruminants

NARCIS (Netherlands)

Os, van M.

1997-01-01

In Northern- and Western-Europe, grass silage is a major component in winter feeding rations for ruminants. The intake of ensiled grass is often lower than the intake of hay or the fresh grass of similar digestibility. This intake depression is attributed to the fermentation products

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

Science.gov (United States)

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

2013-01-01

By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0

Postharvest residues from grass seed crops for bioenergy

OpenAIRE

Simić, Aleksandar; Čolić, Vladislava; Vučković, Savo; Dželetović, Željko; Bijelić, Zorica; Mandić, Violeta

2016-01-01

During grass seed production, a large amount of low forage quality biomass has been produced. Tall growing perennial grasses such as tall fescue (Festuca arundinacea L.) and Italian ryegrass (Lolium multiflorum Lam.) can be used as an alternative source for bioenergy production as they can be grown in less cultivated areas, their residues in seed production could be valuable energy source and can be potentially used as a dual purpose crop (bioenergy and forage). In this research, potentials o...

Analysis of Fusarium causing dermal toxicosis in marram grass planters

NARCIS (Netherlands)

Snijders, CHA; Samson, RA; Hoekstra, ES; Ouellet, T; Miller, JD; deRooijvanderGoes, PCEM; Baar, AJM; Dubois, AEJ; Kauffman, HF

1996-01-01

In the European coastal dunes, marram grass (Ammophila arenaria) is planted in order to control sand erosion. In the years 1986 to 1991, workers on the Wadden islands in the Netherlands planting marram grass showed lesions of skin and mucous membranes, suggesting a toxic reaction. Fusarium culmorum

Grass fields as reservoirs for polyphagous predators (Arthropoda) of aphids (Homopt., Aphididae)

DEFF Research Database (Denmark)

Gravesen, Eigil Vestergaard; Toft, Søren

1987-01-01

In a 4 ha grass field in Denmark three separate plots of 15 times 25 m were cultivated with barley. In each plot a central area of 5 times 5 m were fenced off by a plastic barrier. Thus, each plot consisted of an unfenced area, accessible for predators immigrating from the grass field, and an una......In a 4 ha grass field in Denmark three separate plots of 15 times 25 m were cultivated with barley. In each plot a central area of 5 times 5 m were fenced off by a plastic barrier. Thus, each plot consisted of an unfenced area, accessible for predators immigrating from the grass field...

Hyperspectral remote sensing techniques for grass nutrient estimations in savannah ecosystems

CSIR Research Space (South Africa)

Ramoelo, Abel

2010-03-01

Full Text Available Information on the distribution of grass quality (nutrient concentration) is crucial in understanding rangeland vitality and facilitates effective management of wildlife and livestock. The spatial distribution of grass nutrient concentration occurs...

Bioenergy production from roadside grass

DEFF Research Database (Denmark)

Meyer, Ane Katharina Paarup; Ehimen, Ehiazesebhor Augustine; Holm-Nielsen, Jens Bo

2014-01-01

This paper presents a study of the feasibility of utilising roadside vegetation for biogas production in Denmark. The potential biomass yield, methane yields, and the energy balances of using roadside grass for biogas production was investigated based on spatial analysis. The results show...

Preemergence herbicides on weed control in elephant grass pasture

Directory of Open Access Journals (Sweden)

Alexandre Magno Brighenti

Full Text Available ABSTRACT Elephant grass (Pennisetum purpureum Schum. is an important forage crop that has been proposed as a potential feedstock for bioenergy production. However, weed interference is a major factor limiting elephant grass production. Field experiments were conducted in 2014 and 2015 to evaluate preemergence herbicides for selective weed control in an elephant grass pasture. Herbicide treatments included atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr, and atrazine at label use rates. Weedy and weed-free treatments were included. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine did not cause phytotoxicity on elephantgrass 35 days after treatment (DAT. However, diuron + hexazinone and imazethapyr were the most phytotoxic on elephantgrass, resulting in 81 and 70% phytotoxicity in 2014, and 7 and 6% phytotoxicity in 2015 respectively 35 DAT. All treatments provided effective weed control (>81% with the exception of ethoxysulfuron (0 and 11% in 2014 and 2015, respectively, and atrazine (59% in 2014. These results show that atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine were selectives when applied in preemergence in elephant grass pasture.

Jihadism, Narrow and Wide

DEFF Research Database (Denmark)

Sedgwick, Mark

2015-01-01

The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

Pampas Grass - Orange Co. [ds351

Data.gov (United States)

California Natural Resource Agency — This dataset provides the known distribution of pampas grass (Cortaderia selloana) in southern Orange County. The surveys were conducted from May to June, 2007 and...

Urban Rights-of-Way as Reservoirs for Tall-Grass Prairie Plants and Butterflies

Science.gov (United States)

Leston, Lionel; Koper, Nicola

2016-03-01

Urban rights-of-way may be potential reservoirs of tall-grass prairie plants and butterflies. To determine if this is true, in 2007-2008, we conducted vegetation surveys of species richness and cover, and butterfly surveys of species richness and abundance, along 52 transmission lines and four remnant prairies in Winnipeg, Manitoba. We detected many prairie plants and butterflies within transmission lines. Some unmowed and infrequently managed transmission lines had native plant species richness and total percent cover of native plants comparable to that of similar-sized remnant tall-grass prairies in the region. Although we did not find significant differences in overall native butterfly numbers or species richness between rights-of-way and remnant prairies, we found lower numbers of some prairie butterflies along frequently mowed rights-of-way than within remnant tall-grass prairies. We also observed higher butterfly species richness along sites with more native plant species. By reducing mowing and spraying and reintroducing tall-grass prairie plants, urban rights-of-way could serve as extensive reservoirs for tall-grass prairie plants and butterflies in urban landscapes. Eventually, managing urban rights-of-way as reservoirs for tall-grass prairie plants and animals could contribute to the restoration of tall-grass prairie in the North American Midwest.

Urban Rights-of-Way as Reservoirs for Tall-Grass Prairie Plants and Butterflies.

Science.gov (United States)

Leston, Lionel; Koper, Nicola

2016-03-01

Urban rights-of-way may be potential reservoirs of tall-grass prairie plants and butterflies. To determine if this is true, in 2007-2008, we conducted vegetation surveys of species richness and cover, and butterfly surveys of species richness and abundance, along 52 transmission lines and four remnant prairies in Winnipeg, Manitoba. We detected many prairie plants and butterflies within transmission lines. Some unmowed and infrequently managed transmission lines had native plant species richness and total percent cover of native plants comparable to that of similar-sized remnant tall-grass prairies in the region. Although we did not find significant differences in overall native butterfly numbers or species richness between rights-of-way and remnant prairies, we found lower numbers of some prairie butterflies along frequently mowed rights-of-way than within remnant tall-grass prairies. We also observed higher butterfly species richness along sites with more native plant species. By reducing mowing and spraying and reintroducing tall-grass prairie plants, urban rights-of-way could serve as extensive reservoirs for tall-grass prairie plants and butterflies in urban landscapes. Eventually, managing urban rights-of-way as reservoirs for tall-grass prairie plants and animals could contribute to the restoration of tall-grass prairie in the North American Midwest.

Enhanced precipitation variability decreases grass- and increases shrub-productivity

Science.gov (United States)

Gherardi, Laureano A.; Sala, Osvaldo E.

2015-01-01

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

Optimization of conventional rule curves coupled with hedging rules for reservoir operation

DEFF Research Database (Denmark)

Taghian, Mehrdad; Rosbjerg, Dan; Haghighi, Ali

2014-01-01

As a common approach to reservoir operating policies, water levels at the end of each time interval should be kept at or above the rule curve. In this study, the policy is captured using rationing of the target yield to reduce the intensity of severe water shortages. For this purpose, a hybrid...... to achieve the optimal water allocation and the target storage levels for reservoirs. As a case study, a multipurpose, multireservoir system in southern Iran is selected. The results show that the model has good performance in extracting the optimum policy for reservoir operation under both normal...... model is developed to optimize simultaneously both the conventional rule curve and the hedging rule. In the compound model, a simple genetic algorithm is coupled with a simulation program, including an inner linear programming algorithm. In this way, operational policies are imposed by priority concepts...

Device Physics of Narrow Gap Semiconductors

CERN Document Server

Chu, Junhao

2010-01-01

Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only the semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The last chapter applies the understanding of device physics to photoconductive detectors, photovoltaic infrared detector...

Buffel grass morphoagronomic characterization from cenchrus germplasm active bank.

OpenAIRE

BRUNO, L. R. G. P.; ANTONIO, R. P.; ASSIS, J. G. de A.; MOREIRA, J. N.; LIRA, I. C. de S. A.

2017-01-01

his study aimed to characterize buffel grass accessions of the Cenchrus Germplasm Active Bank (CGAB) from Embrapa Semi - Arid in a morphoagronomic way, checking the descriptors variability and efficiency in accessions on two consecutive cuts. Twenty - five accessions and five buffel grass cultivars were used in randomized complete block design with three replications. Evaluations were conducted after two consecutive cuts, each evaluation performed 90 days after each ...

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

Science.gov (United States)

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

2005-09-10

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

Review of the integrated process for the production of grass biomethane.

Science.gov (United States)

Nizami, Abdul-Sattar; Korres, Nicholas E; Murphy, Jerry D

2009-11-15

Production of grass biomethane is an integrated process which involves numerous stages with numerous permutations. The grass grown can be of numerous species, and it can involve numerous cuts. The lignocellulosic content of grass increases with maturity of grass; the first cut offers more methane potential than the later cuts. Water-soluble carbohydrates (WSC) are higher (and as such methane potential is higher) for grass cut in the afternoon as opposed to that cut in the morning. The method of ensiling has a significant effect on the dry solids content of the grass silage. Pit or clamp silage in southern Germany and Austria has a solids content of about 40%; warm dry summers allow wilting of the grass before ensiling. In temperate oceanic climates like Ireland, pit silage has a solids content of about 21% while bale silage has a solids content of 32%. Biogas production is related to mass of volatile solids rather than mass of silage; typically one ton of volatile solid produces 300 m(3) of methane. The dry solids content of the silage has a significant impact on the biodigester configuration. Silage with a high solids content would lend itself to a two-stage process; a leach bed where volatile solids are converted to a leachate high in chemical oxygen demand (COD), followed by an upflow anaerobic sludge blanket where the COD can be converted efficiently to CH(4). Alternative configurations include wet continuous processes such as the ubiquitous continuously stirred tank reactor; this necessitates significant dilution of the feedstock to effect a solids content of 12%. Various pretreatment methods may be employed especially if the hydrolytic step is separated from the methanogenic step. Size reduction, thermal, and enzymatic methodologies are used. Good digester design is to seek to emulate the cow, thus rumen fluid offers great potential for hydrolysis.

Dichotomy in the NRT gene families of dicots and grass species.

Directory of Open Access Journals (Sweden)

Darren Plett

Full Text Available A large proportion of the nitrate (NO(3(- acquired by plants from soil is actively transported via members of the NRT families of NO(3(- transporters. In Arabidopsis, the NRT1 family has eight functionally characterised members and predominantly comprises low-affinity transporters; the NRT2 family contains seven members which appear to be high-affinity transporters; and there are two NRT3 (NAR2 family members which are known to participate in high-affinity transport. A modified reciprocal best hit (RBH approach was used to identify putative orthologues of the Arabidopsis NRT genes in the four fully sequenced grass genomes (maize, rice, sorghum, Brachypodium. We also included the poplar genome in our analysis to establish whether differences between Arabidopsis and the grasses may be generally applicable to monocots and dicots. Our analysis reveals fundamental differences between Arabidopsis and the grass species in the gene number and family structure of all three families of NRT transporters. All grass species possessed additional NRT1.1 orthologues and appear to lack NRT1.6/NRT1.7 orthologues. There is significant separation in the NRT2 phylogenetic tree between NRT2 genes from dicots and grass species. This indicates that determination of function of NRT2 genes in grass species will not be possible in cereals based simply on sequence homology to functionally characterised Arabidopsis NRT2 genes and that proper functional analysis will be required. Arabidopsis has a unique NRT3.2 gene which may be a fusion of the NRT3.1 and NRT3.2 genes present in all other species examined here. This work provides a framework for future analysis of NO(3(- transporters and NO(3(- transport in grass crop species.

Improving the energy balance of grass-based anaerobic digestion through harvesting optimization

DEFF Research Database (Denmark)

Tsapekos, Panagiotis; Kougias, Panagiotis; Egelund, H.

with a number of coarse barbs) to simultaneously mow and mechanically pretreat two different lignocellulosic substrates. Thus, ensiled meadow grass was initially examined at the first experimental set up. Regarding the second field test, an area sowed with regularly cultivated grass was harvested. In order......) protocol. The findings showed that methane production can efficiently be enhanced by mechanical pretreatment applied at the harvesting step. More specifically, the most effective treatment yielded more than 10% increase in the bioenergy production from both examined grass silages. Our study demonstrates...... that the appropriate harvester can improve the energy output by approximately 2.4 GJ/ha under optimal conditions and subsequently, the overall sustainability of grass-based AD....

Swine wastewater treatment using vertical subsurface flow constructed wetland planted with Napier grass

Directory of Open Access Journals (Sweden)

Pantip Klomjek

2016-09-01

Full Text Available This research aims to investigate the pollutant removal efficiencies in swine wastewater using a vertical subsurface flow constructed wetland (VSF CW planted with two species of Napier grass. The grass productivities were also cultivated and compared in order to provide information for species selection. Twelve treatment units were set up with the VSF CWs planted with Giant Napier grass (Pennisetum purpureum cv. King grass and Dwarf Napier grass (Pennisetum purpureum cv. Mott. with 2 and 5 cm d−1 of hydraulic loading rates (HLR. Comparisons of removal efficiency and grass productivity were analyzed using Duncan's Multiple Range Test and t-test at the significant level 0.05. Both species of Napier grass performed more than 70% of removal efficiency of BOD and TKN. The VSF CW planted with Giant Napier grass at 5 cm d−1 HLR performed the highest BOD removal efficiency of 94 ± 1%, while the 2 cm d−1 HLR removed COD with efficiency of 64 ± 6%. The results also showed the effluent from all treatment units contained averages of BOD, COD, TSS, TKN and pH that followed Thailand's swine wastewater quality standard. Average fresh yields and dry yields were between 4.6 ± 0.4 to 15.2 ± 1.2 and 0.5 ± 0.1 to 2.2 ± 0.1 kg m−2, respectively. The dry yields obtained from four cutting cycles in five months of CW system operation were higher than the ones planted with a traditional method, but declined continuously after each cutting cycle. Both species of Napier grass indicated their suitability to be used in the VSF CW for swine wastewater treatment.

Modelling nutrient concentration to determine the environmental factors influencing grass quality

CSIR Research Space (South Africa)

Dudeni-Tlhone, N

2010-10-01

Full Text Available This paper uses the spatial and the least squares (Analysis of Covariance-ANCOVA) regression methods to evaluate the important environmental factors in estimating quality grass for grazing (based on the nitrogen (N) content in grass...

Nutritive value of Tanzania grass for dairy cows under rotational grazing

Directory of Open Access Journals (Sweden)

Alberto Magno Fernandes

2014-08-01

Full Text Available A nutritional analysis of Tanzania grass (Megathyrsus maximus Jacquin cv. Tanzânia was conducted. Pasture was managed in a rotational grazing system with a 30-day resting period, three days of paddock occupation and two grazing cycles. Ten Holstein × Zebu crossbred cows were kept within a 2-ha area divided into 11 paddocks ha-1. Cows were fed 2 kg of corn meal daily and performance was evaluated by weighing the animals every 14 days and by recording milk production twice a day. Nutritional composition of the Tanzania grass was determined from forage (extrusa samples collected by esophageal fistulae from two animals. The nutritive value of Tanzania grass was estimated according to a modification of the CNCPS evaluation model. Tanzania grass supplemented with 2 kg of corn meal supplied 33.2% more net energy for lactation than required by the animals to produce 13.7 kg of milk day-1. Nevertheless, the amount of metabolizable protein met the daily protein requirement of the animals. Although the model used in the study requires adjustments, Tanzania grass has the potential to produce milk in a rotational grazing system.

The conditions for use of reed canary grass briquettes and chopped reed canary grass in small heating plants; Foerutsaettningar foer anvaendning av roerflensbriketter och hackad roerflen i mindre vaermecentraler

Energy Technology Data Exchange (ETDEWEB)

Paulrud, Susanne; Davidsson, Kent; Holmgren, Magnus A. (Swedish National Testing and Research Inst., Boraas (Sweden)); Hedman, Henry; Oehman, Rikard; Leffler, Joel (ETC, Piteaa (Sweden))

2010-09-15

The aim of this study was to test fuel blends of briquettes and chopped reed canary grass in three existing heating plants (50 kW - 500 kW) and elucidate the requirements for good performance and low emissions. In addition, the study investigated production of reed canary grass briquettes using a Polish screw press developed for straw. Some tests with a bale shredder were also undertaken. The screw press technique is of interest for reed canary grass because it is a simple technique, easy to handle, developed for small scale production, and for straw. The test with reed canary grass in this study showed that the technique worked well but that further adjustments and a longer test period are needed in order to achieve higher bulk density and mechanical strength. The test with chopped reed canary grass shows that a system with a forage harvester is slightly more effective than baling and cutting in a bale shredder. The study concluded that few existing heating plants of size 50 kW-1 MW that currently use wood fuels will be able to use reed canary grass without adjustment, conversion or replacement of the combustion equipment. Reed canary grass has 15-20 times higher ash content than wood briquettes and 2-3 times higher ash content than forest residue; the combustion equipment must be able to handle these properties. The boiler must be equipped with a continuously operating ashing system and it must be possible to move the ash bed mechanically. There is a risk of high content of unburned matter if the residence time in the boiler is too short, due to the structure and low bulk density of the reed canary grass ash. Using a blend of wood briquettes and reed canary briquettes results in lower ash content, but also affects the ash chemistry and tends to lower the initial ash fusion temperature compared to using 100 % reed canary grass. Blending chopped reed canary grass and wood chips in an existing small scale heating plant also requires measures to achieve an even fuel

Complementary DNA cloning of the major allergen Phl p I from timothy grass (Phleum pratense); recombinant Phl p I inhibits IgE binding to group I allergens from eight different grass species

NARCIS (Netherlands)

Laffer, S.; Valenta, R.; Vrtala, S.; Susani, M.; van Ree, R.; Kraft, D.; Scheiner, O.; Duchêne, M.

1994-01-01

BACKGROUND: Grass pollens, such as pollen from timothy grass (Phleum pratense), represent a major cause of type I allergy. OBJECTIVE: In this report we attempted to determine how cross-reactive allergenic components of grass pollens from different species can be represented by a minimum number of

Distribution, Diversity, and Long-Term Retention of Grass Short Interspersed Nuclear Elements (SINEs).

Science.gov (United States)

Mao, Hongliang; Wang, Hao

2017-08-01

Instances of highly conserved plant short interspersed nuclear element (SINE) families and their enrichment near genes have been well documented, but little is known about the general patterns of such conservation and enrichment and underlying mechanisms. Here, we perform a comprehensive investigation of the structure, distribution, and evolution of SINEs in the grass family by analyzing 14 grass and 5 other flowering plant genomes using comparative genomics methods. We identify 61 SINE families composed of 29,572 copies, in which 46 families are first described. We find that comparing with other grass TEs, grass SINEs show much higher level of conservation in terms of genomic retention: The origin of at least 26% families can be traced to early grass diversification and these families are among most abundant SINE families in 86% species. We find that these families show much higher level of enrichment near protein coding genes than families of relatively recent origin (51%:28%), and that 40% of all grass SINEs are near gene and the percentage is higher than other types of grass TEs. The pattern of enrichment suggests that differential removal of SINE copies in gene-poor regions plays an important role in shaping the genomic distribution of these elements. We also identify a sequence motif located at 3' SINE end which is shared in 17 families. In short, this study provides insights into structure and evolution of SINEs in the grass family. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Uptake of Radium by Grass and Shrubs Grown on Mineral Heaps: A Preliminary Study

International Nuclear Information System (INIS)

Laili, Z.; Omar, M.; Yusof, M.A. Wahab; Ibrahim, M.Z.

2015-01-01

A preliminary study of the uptake of 226 Ra and 228 Ra by grass and shrubs grown on mineral heaps was carried out. Activity concentrations of 226 Ra and 228 Ra in grass and shrubs were measured using gamma spectrometry. The result showed that grass and shrubs grown on mineral heaps contained elevated levels of radium compared to grass and shrubs grown on normal soils. Thus, these plants might be used for phytoremediation of radium contaminated soil. (author)

Potential of Cogon Grass as an Oil Sorbent

OpenAIRE

Wiloso, Edi Iswanto; Barlianti, Vera; Anggraini, Irni Fitria; Hendarsyah, Hendris

2012-01-01

Experiments on the potential of Cogon grass (lmperata cylindrica), a weed harmful to other plants, for use as a low-cost and biodegradable oil sorbent were carried out under various spill conditions. Flowers of Cogon grass adsorbed much larger amount of high-viscosity lubricating oil (57.9 g-oil/g-sorbent) than that adsorbed by Peat Sorb (7.7 g-oil/g-sorbent), a commercial oilsorbent based on peat. However, the flowers adsorbed only 27.9 g of low-viscosity crude oillgsorbent. In an oil-water ...

Botanical Composition, Grass Production, and Carrying Capacity of Pasture in Timor Tengah Selatan District

Directory of Open Access Journals (Sweden)

V. E. Se’u

2015-12-01

Full Text Available This study was conducted to analyze the botanical composition, grass production, carrying capacity, and potential production of nutrients in pasture located in Timor Tengah Selatan Regency. The experiment was conducted from February to July 2013, using field survey method. The botanical composition, grass production and carrying capacity on real condition were analyzed descriptively, while the grass production and carrying capacity based of cutting arrangement were analyzed by using randomized block factorial design with 3 altitude locations (Sub District of Mollo Utara with altitude of 1007 m above sea level; Sub District of Noebeba, 500 m ASL, and Sub District of Amanuban Selatan, 65 m ASL x 2 cutting intervals (1 and 2 month and 5 replications. The results showed that the grass type dominated the pasture in the Sub District of Mollo Utara, while legum type was more dominant in the pasture in the Sub Districts of Noebeba and Amanuban Selatan. The potential production of dry matter grass in Timor Tengah Selatan Regency based on real condition was 150 to 390 kg/ha/yr, this could accommodate 0.24 to 0.63 AU/ha/yr. The arrangement of cutting interval by 1 month in Mollo Utara and 2 months in Noebeba and Amanuban Selatan could increase (P<0.05 grass production and carrying capacity. The potential productions of grass nutrients were higher in Sub District of Mollo Utara, while potential production of grass dry matter was higher in Sub Districts of Noebeba and Amanuban Selatan. It was concluded that grass dry matter potential production and carrying capacity in Timor Tengah Selatan Regency were low. The arrangement of cutting interval could increase grass dry matter potential production, carrying capacity, nutrition production, and quality of nutrition.

Thermally treated grass fibers as colonizable substrate for beneficial bacterial inoculum

NARCIS (Netherlands)

Trifonova, R.D.; Postma, J.; Ketelaars, J.J.M.H.; Elsas, van J.D.

2008-01-01

This study investigates how thermally treated (i.e., torrefied) grass, a new prospective ingredient of potting soils, is colonized by microorganisms. Torrefied grass fibers (TGF) represent a specific colonizable niche, which is potentially useful to establish a beneficial microbial community that

Effects of urban grass coverage on rainfall-induced runoff in Xi'an loess region in China

Directory of Open Access Journals (Sweden)

Jing Li

2017-10-01

Full Text Available In this study, laboratory rainfall simulation experiments were conducted to investigate the regulatory effects of grass coverage on rainfall-runoff processes. A total of 80 grass blocks planted with well-grown manilagrass, together with their root systems, were sampled from an eastern suburban area of Xi'an City in the northwest arid area of China and sent to a laboratory for rainfall simulation experiments. The runoff and infiltration processes of a slope with different grass coverage ratios and vegetation patterns were analyzed. The results show that the runoff coefficient decreases with the increase of the grass coverage ratio, and the influence of grass coverage on the reduction of runoff shows a high degree of spatial variation. At a constant grass coverage ratio, as the area of grass coverage moves downward, the runoff coefficient, total runoff, and flood peak discharge gradually decrease, and the flood peak occurs later. With the increase of the grass coverage ratio, the flood peak discharge gradually decreases, and the flood peak occurs later as well. In conclusion, a high grass coverage ratio with the area of grass coverage located at the lower part of the slope will lead to satisfactory regulatory effects on rainfall-induced runoff.

Persistence of Overseeded Cool-Season Grasses in Bermudagrass Turf

OpenAIRE

Thomas Serensits; Matthew Cutulle; Jeffrey F. Derr

2011-01-01

Cool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass di...

BUFFEL GRASS MORPHOAGRONOMIC CHARACTERIZATION FROM Cenchrus GERMPLASM ACTIVE BANK

OpenAIRE

BRUNO, LEILA REGINA GOMES PASSOS; ANTONIO, RAFAELA PRISCILA; ASSIS, JOSÉ GERALDO DE AQUINO; MOREIRA, JOSÉ NILTON; LIRA, IRLANE CRISTINE DE SOUZA ANDRADE

2017-01-01

ABSTRACT This study aimed to characterize buffel grass accessions of the Cenchrus Germplasm Active Bank (CGAB) from Embrapa Semi-Arid in a morphoagronomic way, checking the descriptors variability and efficiency in accessions on two consecutive cuts. Twenty-five accessions and five buffel grass cultivars were used in randomized complete block design with three replications. Evaluations were conducted after two consecutive cuts, each evaluation performed 90 days after each cut. Characterizatio...

Nutritional composition and in vitro digestibility of grass and legume winter (cover) crops.

Science.gov (United States)

Brown, A N; Ferreira, G; Teets, C L; Thomason, W E; Teutsch, C D

2018-03-01

In dairy farming systems, growing winter crops for forage is frequently limited to annual grasses grown in monoculture. The objectives of this study were to determine how cropping grasses alone or in mixtures with legumes affects the yield, nutritional composition, and in vitro digestibility of fresh and ensiled winter crops and the yield, nutritional composition, and in vitro digestibility of the subsequent summer crops. Experimental plots were planted with 15 different winter crops at 3 locations in Virginia. At each site, 4 plots of each treatment were planted in a randomized complete block design. The 15 treatments included 5 winter annual grasses [barley (BA), ryegrass (RG), rye (RY), triticale (TR), and wheat (WT)] in monoculture [i.e., no legumes (NO)] or with 1 of 2 winter annual legumes [crimson clover (CC) and hairy vetch (HV)]. After harvesting the winter crops, corn and forage sorghum were planted within the same plots perpendicular to the winter crop plantings. The nutritional composition and the in vitro digestibility of winter and summer crops were determined for fresh and ensiled samples. Growing grasses in mixtures with CC increased forage dry matter (DM) yield (2.84 Mg/ha), but the yield of mixtures with HV (2.47 Mg/ha) was similar to that of grasses grown in monoculture (2.40 Mg/ha). Growing grasses in mixtures with legumes increased the crude protein concentration of the fresh forage from 13.0% to 15.5% for CC and to 17.3% for HV. For neutral detergent fiber (NDF) concentrations, the interaction between grasses and legumes was significant for both fresh and ensiled forages. Growing BA, RY, and TR in mixtures with legumes decreased NDF concentrations, whereas growing RG and WT with legumes did not affect the NDF concentrations of either the fresh or the ensiled forages. Growing grasses in mixtures with legumes decreased the concentration of sugars of fresh forages relative to grasses grown in monoculture. Primarily, this decrease can be

Interaction between Vetiver Grass Roots and Completely Decomposed Volcanic Tuff under Rainfall Infiltration Conditions

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Ling Xu

2018-01-01

Full Text Available The important role of vetiver grass roots in preventing water erosion and mass movement has been well recognized, though the detailed influence of the grass roots on soil has not been addressed. Through planting vetiver grass at the Kadoorie Farm in Hong Kong and leaving it to grow without artificial maintenance, the paper studies the influence of vetiver grass roots on soil properties and slope stability. Under the natural conditions of Hong Kong, growth of the vetiver grass roots can reach 1.1 m depth after one and a half year from planting. The percentage of grain size which is less than 0.075 mm in rooted soil is more than that of the nonrooted soil. Vetiver grass roots can reduce soil erosion by locking the finer grain. The rooted soil of high finer grain content has a relatively small permeability. As a result, the increase in water content is therefore smaller than that of nonrooted soil in the same rainfall conditions. Shear box test reveals that the vetiver grass roots significantly increased the peak cohesion of the soil from 9.3 kPa to 18.9 kPa. The combined effects of grass roots on hydrological responses and shearing strength significantly stabilize the slope in local rainfall condition.

A proteomic style approach to characterize a grass mix product reveals potential immunotherapeutic benefit.

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Bullimore, Alan; Swan, Nicola; Alawode, Wemimo; Skinner, Murray

2011-09-01

Grass allergy immunotherapies often consist of a mix of different grass extracts, each containing several proteins of different physiochemical properties; however, the subtle contributions of each protein are difficult to elucidate. This study aimed to identify and characterize the group 1 and 5 allergens in a 13 grass extract and to standardize the extraction method. The grass pollens were extracted in isolation and pooled and also in combination and analyzed using a variety of techniques including enzyme-linked immunosorbent assay, liquid chromatog-raphy-mass spectrometry, and sodium dodecyl sulfate-polyacrylam-ide gel electrophoresis. Gold-staining and IgE immunoblotting revealed a high degree of homology of protein bands between the 13 species and the presence of a densely stained doublet at 25-35 kD along with protein bands at approximately 12.5, 17, and 50 kD. The doublet from each grass species demonstrated a high level of group 1 and 5 interspecies homology. However, there were a number of bands unique to specific grasses consistent with evolutionary change and indicative that a grass mix immunotherapeutic could be considered broad spectrum. Sodium dodecyl sulfate-polyacrylamide gel electro-phoresis and IgE immunoblotting showed all 13 grasses share a high degree of homology, particularly in terms of group 1 and 5 allergens. IgE and IgG enzyme-linked immunosorbent assay potencies were shown to be independent of extraction method.

Narrow dibaryon resonances

International Nuclear Information System (INIS)

Kajdalov, A.B.

1986-01-01

Experimental data on np interactions indicating to existence of narrow resonances in pp-system are discussed. Possible theoretical interpretations of these resonances are given. Experimental characteristics of the dibaryon resonances with isospin I=2 are considered

Using GAMM to examine inter-individual heterogeneity in thermal performance curves for Natrix natrix indicates bet hedging strategy by mothers.

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Vickers, Mathew J; Aubret, Fabien; Coulon, Aurélie

2017-01-01

The thermal performance curve (TPC) illustrates the dependence on body- and therefore environmental- temperature of many fitness-related aspects of ectotherm ecology and biology including foraging, growth, predator avoidance, and reproduction. The typical thermal performance curve model is linear in its parameters despite the well-known, strong, non-linearity of the response of performance to temperature. In addition, it is usual to consider a single model based on few individuals as descriptive of a species-level response to temperature. To overcome these issues, we used generalized additive mixed modeling (GAMM) to estimate thermal performance curves for 73 individual hatchling Natrix natrix grass snakes from seven clutches, taking advantage of the structure of GAMM to demonstrate that almost 16% of the deviance in thermal performance curves is attributed to inter-individual variation, while only 1.3% is attributable to variation amongst clutches. GAMM allows precise estimation of curve characteristics, which we used to test hypotheses on tradeoffs thought to constrain the thermal performance curve: hotter is better, the specialist-generalist trade off, and resource allocation/acquisition. We observed a negative relationship between maximum performance and performance breadth, indicating a specialist-generalist tradeoff, and a positive relationship between thermal optimum and maximum performance, suggesting "hotter is better". There was a significant difference among matrilines in the relationship between Area Under the Curve and maximum performance - relationship that is an indicator of evenness in acquisition or allocation of resources. As we used unfed hatchlings, the observed matriline effect indicates divergent breeding strategies among mothers, with some mothers provisioning eggs unequally resulting in some offspring being better than others, while other mothers provisioned the eggs more evenly, resulting in even performance throughout the clutch. This

Invasive grasses change landscape structure and fire behavior in Hawaii

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Lisa M. Ellsworth; Creighton M. Litton; Alexander P. Dale; Tomoaki Miura

2014-01-01

How does potential fire behavior differ in grass-invaded non-native forests vs open grasslands? How has land cover changed from 1950–2011 along two grassland/forest ecotones in Hawaii with repeated fires? A study on non-native forest with invasive grass understory and invasive grassland (Megathyrsus maximus) ecosystems on Oahu, Hawaii, USA was...

Ensiling as pretreatment of grass for lignocellulosic biomass conversion

DEFF Research Database (Denmark)

Ambye-Jensen, Morten

for subsequent enzymatic saccharification of cellulose and hemicellulose, by using the temperate grass Festulolium Hykor. The method was additionally combined with hydrothermal treatment, in order to decrease the required severity of an industrial applied pretreatment method. The first part of the project...... conditions providing the best possible pretreatment effect. The parameters were biomass composition, varied by ensiling of four seasonal cuts of grass, different dry matter (DM) content at ensiling, and an addition of different lactic acid bacteria species. First of all, the study confirmed that ensiling can...... act as a method of pretreatment and improve the enzymatic cellulose convertibility of grass. Furthermore, low DM ensiling was found to improve the effects of pretreatment due to a higher production of organic acids in the silage. The effect of applied lactic acid bacteria species was, however...

Cell wall composition throughout development for the model grass Brachypodium distanchyon

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David eRancour

2012-12-01

Full Text Available Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distanchyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distanchyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e. leaves, sheaths, stems and roots at three developmental stages of 1 12-day seedling, 2 vegetative-to-reproductive transition, and 3 mature seed-fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distanchyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exists between Brachypodium and agronomical important C3 grasses, Brachypodium distanchyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production.

First evidence of grass carp recruitment in the Great Lakes Basin

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Chapman, Duane C.; Davis, J. Jeremiah; Jenkins, Jill A.; Kocovsky, Patrick M.; Miner, Jeffrey G.; Farver, John; Jackson, P. Ryan

2013-01-01

We use aging techniques, ploidy analysis, and otolith microchemistry to assess whether four grass carp Ctenopharyngodon idella captured from the Sandusky River, Ohio were the result of natural reproduction within the Lake Erie Basin. All four fish were of age 1 +. Multiple lines of evidence indicate that these fish were not aquaculture-reared and that they were most likely the result of successful reproduction in the Sandusky River. First, at least two of the fish were diploid; diploid grass carp cannot legally be released in the Great Lakes Basin. Second, strontium:calcium (Sr:Ca) ratios were elevated in all four grass carp from the Sandusky River, with elevated Sr:Ca ratios throughout the otolith transect, compared to grass carp from Missouri and Arkansas ponds. This reflects the high Sr:Ca ratio of the Sandusky River, and indicates that these fish lived in a high-strontium environment throughout their entire lives. Third, Sandusky River fish were higher in Sr:Ca ratio variability than fish from ponds, reflecting the high but spatially and temporally variable strontium concentrations of southwestern Lake Erie tributaries, and not the stable environment of pond aquaculture. Fourth, Sr:Ca ratios in the grass carp from the Sandusky River were lower in their 2011 growth increment (a high water year) than the 2012 growth increment (a low water year), reflecting the observed inverse relationship between discharge and strontium concentration in these rivers. We conclude that these four grass carp captured from the Sandusky River are most likely the result of natural reproduction within the Lake Erie Basin.

Cell wall composition throughout development for the model grass Brachypodium distachyon

Science.gov (United States)

Rancour, David M.; Marita, Jane M.; Hatfield, Ronald D.

2012-01-01

Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distachyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distachyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e., leaves, sheaths, stems, and roots) at three developmental stages of (1) 12-day seedling, (2) vegetative-to-reproductive transition, and (3) mature seed fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distachyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exist between Brachypodium and agronomical important C3 grasses, Brachypodium distachyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production. PMID:23227028

Hygrothermal Properties and Performance of Sea Grass Insulation

DEFF Research Database (Denmark)

Eriksen, Marlene Stenberg Hagen; Laursen, Theresa Back; Rode, Carsten

2008-01-01

In the attempt to obtain knowledge of the hygrothermal properties of sea grass as thermal insulation, experiments have been carried out in the laboratory to determine the thermal conductivity, sorption properties and the water vapour permeability of the material. In order to investigate the hygro......In the attempt to obtain knowledge of the hygrothermal properties of sea grass as thermal insulation, experiments have been carried out in the laboratory to determine the thermal conductivity, sorption properties and the water vapour permeability of the material. In order to investigate...

Determination of 90Sr in grass and soil

International Nuclear Information System (INIS)

Bajo, S.; Keil, R.

1994-10-01

A radiochemical method for the determination of 90 Sr in non-contaminated grass and soil is presented. The method is based on the leaching of 90 Sr from the mineralized samples followed by liquid-liquid extraction of 90 Y, its short lived daughter, by tributylphosphate and precipitation of Y-oxalate, which is counted in a low-level proportional counter. Based on dried samples of 30 g of soil and 100 g of grass the limit of detection is about 0.1 Bq/kg for both materials. (author) figs., tabs., 43 refs

Investing in Cognac Producing Vineyards to Hedge Wealth While Receiving High Returns

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Hakob Hakobyan

2015-07-01

Full Text Available The general trend over the last decade for investments has been moving towards emerging markets, where investors are promised high returns for risky investments. These kind of investments favor the brave and bold, but are frightening for the risk averse. In this paper I will be presenting the opportunities that an investment into cognac producing vineyards can offer. High return and relatively low risk investment opportunities that exists in France. Included in the paper will be examples of large investments made recently into the industry. I will analyze the trends in the market over the past 8 years for the prices of land, cognac itself and the ease of sales of such products. There will also be an in-depth explanation of why cognac is today’s least risky product to invest into, comparing it to the Champagne regions’ similar historic trends. The findings show that land prices have increased at an average of 10% while simultaneously the price of cognac, has grow at an average of 14%. This product also has a unique hedging opportunity for investors. In short, excluding the growth of cognac prices in general the product itself gains value the longer it is stored, by an average of 12%. In this industry there are 5 big players that compete with each other on quality and also access to future stocks. This reality gives an investor the unique ability to sign futures contracts for 100% of their production over a 5 year period (standard market contract. Similar contracts can be signed with cooperatives who manage the lands for the investor, making the investment hassle free. This allows for an assured projection of both costs and returns for an unprecedented length of time compared to any other industry today. In conclusion, cognac producing vineyards are an investment that can potentially bring high returns, while being able to hedge the investment and see capital gains over the course of time. There will be a final simulation of a 5 year

Current Models for Transcriptional Regulation of Secondary Cell Wall Biosynthesis in Grasses

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Xiaolan Rao

2018-04-01

Full Text Available Secondary cell walls mediate many crucial biological processes in plants including mechanical support, water and nutrient transport and stress management. They also provide an abundant resource of renewable feed, fiber, and fuel. The grass family contains the most important food, forage, and biofuel crops. Understanding the regulatory mechanism of secondary wall formation in grasses is necessary for exploiting these plants for agriculture and industry. Previous research has established a detailed model of the secondary wall regulatory network in the dicot model species Arabidopsis thaliana. Grasses, branching off from the dicot ancestor 140–150 million years ago, display distinct cell wall morphology and composition, suggesting potential for a different secondary wall regulation program from that established for dicots. Recently, combined application of molecular, genetic and bioinformatics approaches have revealed more transcription factors involved in secondary cell wall biosynthesis in grasses. Compared with the dicots, grasses exhibit a relatively conserved but nevertheless divergent transcriptional regulatory program to activate their secondary cell wall development and to coordinate secondary wall biosynthesis with other physiological processes.

Endophytic Epichloë species and their grass hosts: from evolution to applications.

Science.gov (United States)

Saikkonen, Kari; Young, Carolyn A; Helander, Marjo; Schardl, Christopher L

2016-04-01

The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this. In many cases the detected ecological importance of Epichloë species is directly or indirectly linked to defensive mutualism attributable to alkaloids of fungal-origin. Now, modern genetic and molecular techniques enable the precise studies on evolutionary origin of endophytic Epichloë species, their coevolution with host grasses and identification the genetic variation that explains phenotypic diversity in ecologically relevant characteristics of Epichloë-grass associations. Here we briefly review the most recent findings in these areas of research using the present knowledge of the genetic variation that explains the biosynthetic pathways driving the diversity of alkaloids produced by the endophyte. These findings underscore the importance of genetic interplay between the fungus and the host in shaping their coevolution and ecological role in both natural grass ecosystems, and in the agricultural arena.

Aggressiveness of loose kernel smut isolate from Johnson grass on sorghum line BTx643

Science.gov (United States)

An isolate of loose kernel smut obtained from Johnson grass was inoculated unto six BTx643 sorghum plants in the greenhouse to determine its aggressiveness. All the BTx643 sorghum plants inoculated with the Johnson grass isolate were infected. Mean size of the teliospores from the Johnson grass, i...

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

Science.gov (United States)

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

2018-01-01

A relevant proportion of allergic rhinoconjunctivitis (ARC) patients experience recurrent symptoms after successfully completing allergen immunotherapy (AIT). This prospective, controlled, noninterventional study used internationally standardized instruments to determine the clinical effects of a preseasonal, ultra-short-course booster AIT on clinical outcome parameters. This two-arm study included patients aged ≥12 years with recurrent grass pollen-induced seasonal AR who had completed a successful course of any grass pollen AIT at least 5 years before enrolment. Overall, 56 patients received one preseasonal short-course booster AIT using tyrosine-absorbed grass pollen allergoids containing the adjuvant monophosphoryl lipid A (MPL ® ); 51 control patients received symptomatic medication. The combined symptom and medication score (CSMS) was recorded in the (peak) grass pollen season. Furthermore, concomitant (antiallergic) medication use, the patients' state of health, Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) results and safety/tolerability of the treatment were assessed. The CSMS in the peak grass pollen season was significantly lower in the booster AIT group (Δ=38.4%, Pallergoids containing the adjuvant MPL ® effectively prevents re-occurrence of symptoms in patients with grass pollen-induced ARC. © 2017 The Authors. Allergy Published by John Wiley & Sons Ltd.

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

Science.gov (United States)

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

2011-04-01

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

Group 5 allergens of timothy grass (Phl p 5) bear cross-reacting T cell epitopes with group 1 allergens of rye grass (Lol p 1).

Science.gov (United States)

Müller, W D; Karamfilov, T; Bufe, A; Fahlbush, B; Wolf, I; Jäger, L

1996-04-01

Selected human T cell clones reactive with group 5 allergens of timothy grass (Phl p 5) were cross-stimulated in specific proliferation assays with group 1 allergens of rye grass (Lol p 1). Such interspecies cross-reactivities result obviously from structural motifs presented on defined Phl p 5 fragments as shown with recombinant Phl p 5 products.

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

Science.gov (United States)

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

2018-01-01

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