Behaviour of pultruded beam-to-column joints using steel web cleats

Response of pultruded Fibre Reinforced Polymer (FRP) beam-to-column joints with steel bolted web cleats is studied through physical testing. Two joint configurations are considered with either three or two bolts per cleat leg, as per drawings in a pultruder’s Design Manual. Moment-rotation curves, failure modes and potential performance gains from semi-rigid action are determined from two batches, each having six nominally identical joints. Results show that initial joint properties for stiffness and moment can possess, at 19 to 62%, an extremely high coefficient of variation. All joints failed by fracturing within the FRP column’s flange outstands. Because this failure mode has not been reported previously there is a need to establish how its existence influences joint design. As joint properties for the three- and two-bolted configurations are not significantly different, the middle (third) bolt is found to be redundant. Damage is shown to initiate within the column flange outstands when the mid-span deflection of a 5.08 m span beam, subjected to a uniformly distributed load, is span/500. This is half the serviceability vertical deflection limit recommended in the EUROCOMP Design Code and Handbook. The mean joint moment resistance for design is established to be 2.9 kNm and this is 1.5 times the moment for damage onset

On Term Structure Models of Commodity Futures Prices and the Kaldor-Working Hypothesis

Both prices and the volatility of storable agricultural commodity futures contracts have been rising since 2005 and particularly since 2007. This paper aims to answer two principal questions: (i) How has the behavior of these futures prices over time and across maturities changed with the rise of biofuels and their demand-side pres- sure on corn and related crops?, and (ii) Is there now stronger or weaker evidence of the Kaldor-Working convenience yield-storage hypothesis, whereby futures price backwardation can be explained by the high value of remaining inventory stocks when these are near stockouts? The empirical application is to Chicago Board of Trade corn, wheat and soybeans futures. To make use of all available futures data rather than only the nearby, this paper adopts a recently developed affine term structure model approach and conducts estimation in state-space form using the Kalman filter. A novel aspect of the research is that it allows an arbitrary number N of state vari- ables, where more variables provide further precision and curvature but at a higher computational cost. It is found that a three-state variable model containing both ran- dom walk and mean reversion components provides the most parsimonious fit during 1988-2004, but that a simple one-state variable model is optimal for the period 2005- 2007. The main implication is that futures prices since 2005 behave much more like a \random walk" than before. Also, the model allows us to estimate the term struc- ture of volatility and it is found that distant maturity futures should be expected to be much more volatile than historically normal. Two practical but only tentative implications are: (a) hedgers should use significantly lower hedge ratios than before, and (b) for traders, the classic Black-Scholes option pricing solution should perform better now than it has historically. Lastly, the paper finds partial empirical support for the convenience yield relationship with relative inventory stocks, especially for soybeans and wheat.Agricultural Finance, C52, C53, G12, G13, Q13, Q14,

Managing Producer Price Risk in Mexico with Quantos and Dual Risk Commodity-Foreign Exchange Hedges

Replaced with revised version of paper 07/21/10.Marketing, Risk and Uncertainty,

The Confidence Limits of a Geometric Brownian Motion

This paper investigates whether the assumption of Brownian motion often used to describe commodity price movements is satisfied. Using historical data from 17 commodity futures contracts specific tests of fractional and ordinary Brownian motion are conducted. The analyses are conducted under the null hypothesis of ordinary Brownian motion against the alternative of persistent or ergodic fractional Brownian motion. Tests for fractional Brownian motion are based on a variance ratio test. However, standard errors based on Monte Carlo simulations are quite high, meaning that the acceptance region for the null hypothesis is large. The results indicate that for the most part, the null hypothesis of ordinary Brownian motion cannot be rejected for 14 of 17 series. The three series that did not satisfy the tests were rejected because they violated the stationarity property of the random walk hypothesis.Marketing,

Spurious Long Memory in Commodity Futures: Implications for Agribusiness Option Pricing

Long memory, and more precisely fractionally integration, has been put forward as an explanation for the persistence of shocks in a number of economic time series data as well as to reconcile misleading findings of unit roots in data that should be stationary. Recent evidence suggests that long memory characterizes not commodity futures prices but rather price volatility (generally defined as $L_p$ norms of price logreturns). One implication of long memory in volatility is the mispricing of options written on commodity futures, the consequence of which is that fractional Brownian motion should replace geometric Brownian motion as the building block for option pricing solutions. This paper asks whether findings of long memory in volatility might be spurious and caused either by fragile and inaccurate estimation methods and standard errors, by correlated short memory dynamics, or by alternative data generating processes proven to generate the illusion of long memory. We find that for nine out of eleven agricultural commodities for which futures contracts are traded, long memory is spurious but is not caused by the effect of short memory. Alternative explanations are addressed and implications for option pricing are highlighted.Q13, Q14, Marketing, C52, C53, G12, G13,

Type I and Type II Errors in the Unit Root Determination of a Fractional Brownian Motion

Economists who deal with time-series data usually take the unit root test as the ‘prerequisite’ test for a Brownian motion. It is typical for any researchers to apply a battery of well-known unit root tests to their models to confirm stationarity in the model specification. Nonetheless, often times, we see a conclusion that fail to reject the null in favor of the existence of unit root even though the model specification is such that the lag coefficients of an AR(q) process do not sum up to unity. In this study, we show that having the sum of the lag coefficients equals to unity is indeed a necessary and sufficient condition for the existence of a unit root. Hence, the aforementioned incident will lead to a type II error in the unit root determination. On the other hands, type I error results when we reject the null that there exists a unit root when in fact the null is true. The fractional Brownian motion (fBm) process which has stationary but not necessarily independent increments is used to convey the findings of this study. We use Hurst exponent as a gauge for persistency in the data and show that a fBm process is a legitimate stochastic process with unit root even though it exhibits a degree of persistency in time.Unit root, Hurst exponent, Fractional Brownian Motion, Financial Economics, Risk and Uncertainty,

IMPACT OF THE 2002 BIOTERRORISM ACT ON THE NEW JERSEY FOOD INDUSTRY

This paper provides an overview of the four key sections of the Public Health Security and Bioterrorism Preparedness and Response Act of 2002, with regard to Administrative Detention (Section 303), Facilities Registration (Section 305), Records and Maintenance (Section 306), and Prior Notice of Food Imports (Section 307). The potential impacts of the Bioterrorism Act on the food industry are examined through qualitative analysis of industry submissions to the Food and Drug Administration (FDA) docket for each provision, and quantitatively through survey results, which were administered online by the Food Institute (FI) of Woodbridge, NJ and analyzed by Rutgers, Food Policy Institute (FPI). Of the four key sections from the Bioterrorism Act that most affect the food industry, stakeholders were surveyed on two sections, Prior notice of Food Imports and Facilities Registration. While survey responses reveal that many food firms are aware of pending Bioterrorism Act policies, few however, have taken action towards compliance. Facilities registration is touted as the least cumbersome in terms of compliance. Results indicate that 50 percent of food industry professionals surveyed were not aware that many food firms must register with the FDA by the 12 December 2003 deadline; and, 20 percent, while aware of the facilities registration deadline, have done nothing to prepare. Being unprepared for and subsequently complying with Bioterrorism Act rules is an overarching concern, which is apparent in both the survey results and docket summaries. Moreover, upon review of docket submissions to the FDA, it seems that food firms are generally sympathetic towards the need for increased food system security; however, the impact of the Bioterrorism Act can be both daunting and costly. Many perceive that significant changes to capitol costs will be required to meet FDA standards.Agribusiness,

The Impact of an Innovative Human Resource Function on Firm Performance: the Moderating Role of Financing Strategy

The current study examined the impact of the human resource function and financing strategyon the financial performance of 104 UK manufacturing firms. Hypotheses are drawn from aresource-based perspective on human resource management and a financial theoryperspective on capital structure. Results show that an innovative HR function is significantlyrelated to economic performance. However, the relationship between an innovative HRfunction and economic performance was moderated by the firm¿s financing strategy. Firmsobtained higher returns from an innovative HR function when pursuing a low leveraging(debt) financing strategy, a finding consistent with modern finance theory notions that firmspecificstrategic assets provide greatest value when financed primarily through equity asopposed to debt.human resource function, manufacturing, firm performance, asset characteristics

ECONOMICS, HYSTERESIS AND AGROTERRORISM

Environmental Economics and Policy,

Integrating ecology into macroevolutionary research

On 9 March, over 150 biologists gathered in London for the Centre for Ecology and Evolution spring symposium, ‘Integrating Ecology into Macroevolutionary Research’. The event brought together researchers from London-based institutions alongside others from across the UK, Europe and North America for a day of talks. The meeting highlighted methodological advances and recent analyses of exemplar datasets focusing on the exploration of the role of ecological processes in shaping macroevolutionary patterns