Reducing Ammonia Volatilization from Maize Fields with Separation of Nitrogen Fertilizer and Water in an Alternating Furrow Irrigation System

The objective of this 2-yr field trial, with a central composite rotatable design, was to assess and quantify the effects of separation of nitrogen fertilizer and water with alternating furrow irrigation （SNWAFI） practices on soil ammonia （NH3） emission during the summer maize （Zea mays L.） growing season. Ammonia volatilization after N sidedress and irrigation ranged from 4.8 to 17.0 kg N ha-1 and 6.2 to 20.6 kg N hal, respectively, in 2008 and 2009. The lower N input contributed to lower NH3 loss but lower yield, whereas the higher N input induced higher yield as well as higher NH3 loss. Ammonia intensity （NH3 volatilization per crop yield） after N sidedress and irrigation was 1.2-3.0 kg NH3-N t-1 yield in 2008 and 1.1-3.2 kg NH3-N t1 yield in 2009. The predicted minimum NH3 intensity in 2008 was 1.6 kg NH3-N fl yield and was obtained with the combined application of 127 kg N ha^-1 and 108 mm irrigation water. In 2009, the predicted minimum NH3 intensity was 1.3 kg NH3-N t-j yield and was obtained with the combined application of 101 kg N ha-1 and 83 mm irrigation water. We conclude that SNWAFI practices with optimum rates of water and fertilizer can significantly reduce soil NH3 intensity and maintain yield. It was more beneficial for sustainable farming strategies to minimize the NH3 intensity rather than reduce absolute NH3 emissions alone.

Volatility Structures of ForwardRates and the Dynamics of the TermStructure:a Multifactor Case

For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies conditions on the volatility structure of forward rates that permit the dynamics of the term structure to be represented by a finite-dimensional state variable Markov process. In the deterministic volatility case, we interpret then-factor model as a sum ofn unidimensional models.

Performance of Islamic and conventional stock indices:empirical evidence from an emerging economy

Background:This study aims to investigate the extent to which the conditional volatilities of both Shari’ah compliant stock and conventional stock are related to those of interest rate and exchange rate in the emerging economy of Pakistan.Methods:We used KMI 30 and KSE 100 indices for Islamic and conventional stock for the period of July 2008 to November 2013.We employed Generalized Autoregressive Conditional Heteroskedastic in the mean(GARCH-M)model.This framework relaxes constancy assumption of classical linear regression(CLRM)model and allows exchange rate and interest rate volatility to evolve over time.The GARCHM framework also reveals results about risk-return trade-off in the context of both Islamic and conventional stock indices.Results:The findings show positive and statistically significant effect of interest rate volatility on KSE-100,whereas KMI-30 remains unaffected by the same.Exchange rate volatility is found to be significant for both conventional and Islamic indices.The relationship of risk coefficient(γ)and stocks returns,as expected,is positive and statistically significant for both KMI-30 and KSE-100.This result is consistent with the theory of risk-return trade-off.The results of parametric t-test show significant difference between returns of both indices.This implies that Shari’ah compliant stock index(KMI-30)of Pakistan underperforms its conventional counterpart.Conclusion:By using different performance measures(Sharp ratio,Jensen alpha,Treynor ratio),this study also investigates the hypothesis that Islamic stock index has inferior performance compared with unscreened conventional counterparts due to availability of a smaller investment universe,increased monitoring costs,and limited diversification.

Why Does the World Need a Reserve Asset with a Hard Anchor？,

From the 1970s, the global currency system has two features： the use of one or a few sovereign currencies as the global reserve asset and the floating exchange rate regime between major currencies. This paper points out that the costs of the dollar＇s use as an international reserve currency exceed the benefits for both the US and the rest of the world. These costs include the exporting of American manufacturing as a byproduct of its current account deficit needed to supply its currency to the rest of the world. In addition to the detriment to trade from unpredictable exchange rate fluctuations, the termination of the U.S. obligation to redeem its currency for gold also removed an important restraint on deficit financing for the US and many other countries in the short-run, thus promoting excessive leverage that was a major contributor to the 2008 financial crisis. The paper suggests replacing several main countries＇ currencies in international reserves with a real Special Drawing Right （SDR） issued according to currency board rules.

Catalytic removal of phenol from gas streams by perovskite-type catalysts

Three perovskite-type catalysts prepared by citric acid method are applied to remove phenol from gas streams with the total flow rate of 300 mL/min, corresponding to a GHSV of 10,000/hr. LaMnO3 catalyst is first prepared and further partially substituted with Sr and Cu to prepare Lao.sSro.2MnO3 and Lao.sSro.2Mno.sCuo.203, and catalytic activities and fundamen- tal characteristics of these three catalysts are compared. The results show that phenol removal efficiency achieved with Lao.sSro.2Mno.sCuo.203 reaches 100% with the operating temperature of 200℃ and the rate of mineralization at 300℃ is up to 100%, while the phenol removal efficiencies achieved with Lao.sSro.2MnO3 and LaMnO3 are up to 100% with the operating temperature of 300℃ and 400℃, respectively. X-ray photoelectron spectroscopy （XPS） analysis shows that the addition of Sr and Cu increases the lattice oxygen of Lao.sSro.2Mno.sCuo.203, and further increases mobility or availability of lattice oxygen. The results indicate that Lao.sSro.2Mno.sCuo.203 has the best activity for phenol removal among three catalysts prepared and the catalytic activity of phenol oxidation is enhanced by the introduction of Sr and Cu into LaMnO3. Apparent activation energy of 48 kJ/mol is calculated by Mars-Van Krevelen Model for phenol oxidation with Lao.sSro.2Mno.sCuo.203 as catalyst.