نتایج جستجو برای: c52

تعداد نتایج: 377  

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1988
shahram yaghmai

subsequent to phytochemical investigation on scutellaria lateriflora (labiatae) from mazandaran provincein iran, the wax ester fraction of the leaves has been investigated. using tlc, cc glc and glc-ms, the alkyl esters of the epicuticular wax was analysed. total concentration of the esters was 35% and it was shown to be composed of a homologous series having various chain lengths in the range ...

Journal: :international journal of business and development studies 0

this paper aims to investigate the role of each aggregate spending component in the monetary policy transmission in indonesia. it assesses the relative strength of the role of each spending component in the monetary policy transmission. in so doing, this study employs the contribution analysis, which is calculated based on the cumulative impulse response of each component of gdp to a monetary p...

2012
Isaiah Andrews

This paper considers the problem of speci cation testing in general parametric models and shows that for a wide class of models the hypothesis of correct speci cation is equivalent to a continuum of moment equalities. Using these moment equalities we construct a class of speci cation tests that have correct asymptotic size in general parametric models, including stationary time series models, a...

2010
Sean McGill Vladimir N. Nesterov Stephanie L. Gould

In the title complex, [Zn(C(48)H(36)N(4))]·CH(2)Cl(2), the Zn(II) atom lies on an inversion center and the dichloro-methane solvent mol-ecule is disordered around an inversion center. The tolyl substituents are twisted compared to the central aromatic ring system of the porphyrin, similar to what is seen in previously published structures of this molecule [Dastidar & Goldberg (1996 ▶). Acta Cry...

Journal: :The econometrics journal 2009
James J Heckman Petra E Todd

A Note on Adapting Propensity Score Matching and Selection Models to Choice Based Samples The probability of selection into treatment plays an important role in matching and selection models. However, this probability can often not be consistently estimated, because of choicebased sampling designs with unknown sampling weights. This note establishes that the selection and matching procedures ca...

2011
Michaela Denk Michael Weber Ann McPhail

International organizations collect data from national authorities to create multivariate cross-sectional time series for their analyses. As data from countries with not yet wellestablished statistical systems may be incomplete, the bridging of data gaps is a crucial challenge. This paper investigates data structures and missing data patterns in the crosssectional time series framework, reviews...

2007

When bidders anticipate an opportunity for resale trade, tlze value of winning an auction is determined in part by the option values of buying and selling in tlze secondary market. One iinplication is that a bidder's willingness to pa)) at an auction increases with the expected level of competition between resale buyers. Empirical evidence from auctions of timber contracts supports this predict...

2012
Jhon James Mora Rodriguez Juan Muro

In the presence of selection bias, traditional estimators of pseudo panel data are inconsistent. In this paper, the authors derive the conditions under which consistence is achieved in pseudo-panel estimation and propose a simple test of selection bias. Specifically, they propose a Wald test for the null hypothesis that there is no selection bias. Under rejection of the null hypothesis, the aut...

2007
Todd E. Clark Michael W. McCracken

This paper examines the asymptotic and finite-sample properties of tests of equal forecast accuracy applied to direct, multi–step predictions from both non-nested and nested linear regression models. In contrast to earlier work in the literature, our asymptotics take account of the real-time, revised nature of the data. Monte Carlo simulations indicate that our asymptotic approximations yield r...

2004
Hashem Pesaran Allan Timmermann

This paper considers the problems facing decision makers using econometric models in real time. It identifies the key stages involved and highlights the role of automated systems in reducing the effect of data snooping. It sets out many choices that researchers face in construction of automated systems and discusses some of the possible ways advanced in the literature for dealing with them. The...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید