Agriculrural ecosystems comprise an estimated 113 of the land surface of the earth (Houghton ec al .. 1983) a.nd include some of the mosc productive and carbon-rich soils. As a result they play a significant role in the storage and release of C within the terresrrial carbon cycle. At the same time these ecosystems are higllly impacted through human activities and thus processes determining net ...

ABSTRACT Accounting studies often examine whether the relation between X and Y varies with a moderating variable, M, by including an interactive term, × in regression. We provide plain-English guidance on why, how, when to use control variables, Z, interaction tests. A simulation simple descriptions demonstrate how interacted controls affect coefficient estimates interpretations. In particular,...

Background: Allogenic hematopoietic stem cell transplantation (HSCT) is a strategy used for treatment of different malignant diseases. However, success of allo-HSCT can be hampered by graft-versus-host-disease (GVHD). Natural killer (NK) cells may play an important role in activating antigen presenting cells and subsequent activation of T cells. The main purpose of this study was the evaluation...

We present an exact test for whether two random variables that have known bounds on their support are negatively correlated. The alternative hypothesis is that they are not negatively correlated. No assumptions are made on the underlying distributions. We show by example that the Spearman rank correlation test as the competing exact test of correlation in nonparametric settings rests on an addi...

In the existing Statistics and Econometrics literature, there does not exist a statistical test which may for all kinds of roots characteristic polynomial leading to an unstable dynamic response, i.e., positive negative real unit roots, complex lying inside circle. This paper develops is sufficient prove stability (in context polynomial) univariate as well multivariate time series without havin...

We construct an endogenous growth model and we employ empirical analysis to investigate the link between foreign aid and production inefficiency in the presence of different political orientations in the recipient country. Using a panel of 124 countries from 1971 to 2007 and the production frontier toolbox, controlling for unobserved heterogeneity, time horizons, the sources of aid, and the tim...

We consider testing about the slope parameter β when Y −Xβ is assumed to be an exchangeable process conditionally on X. This framework encompasses the semi-parametric linear regression model. We show that the usual Fisher’s procedure have non trivial exact rejection bound under the null hypothesis Rβ = γ. This bound derives from the Markov inequality and a close inspection of multivariate momen...

* This work has been funded by the Spanish CICYT contracts: TIC2002-04491-C01/02 and CAM (07T/0034/2003 1) Abstract The work presented here addresses a key aspect of the data fusion process carried out by A-SMGCS Surveillance, needed to take maximum advantage from the simultaneous use of diverse detection and measurement technologies with complementary characteristics. The core function, Survei...

This paper considers a decision-maker who prefers to make a point decision when the object of interest is interval-identi…ed with regular bounds. When the bounds are just identi…ed along with known interval length, the local asymptotic minimax decision with respect to a symmetric convex loss function takes an obvious form: an e¢ cient lower bound estimator plus the half of the known interval le...