Forecasting with Spatial Panel Data

This paper compares various forecasts using panel data with spatial error correlation. The true data generating process is assumed to be a simple error component regression model with spatial remainder disturbances of the autoregressive or moving average type. The best linear unbiased predictor is compared with other forecasts ignoring spatial correlation, or ignoring heterogeneity due to the individual effects, using Monte Carlo experiments. In addition, we check the performance of these forecasts under misspecification of the spatial error process, various spatial weight matrices, and heterogeneous rather than homogeneous panel data models.forecasting, BLUP, panel data, spatial dependence, heterogeneity

Homogeneous, heterogeneous or shrinkage estimators? Some empirical evidence from French regional gasoline consumption

This paper contrasts the performance of heterogeneous and shrinkage estimators versus the more traditional homogeneous panel data estimators. The analysis utilizes a panel data set from 21 French regions over the period 1973-1998 and a dynamic demand specification to study the gasoline demand in France. Out-of-sample forecast performance as well as the plausibility of the various estimators are contrasted.Panel data; French gasoline demand; Error components; Heterogeneous estimators; Shrinkage estimators

Joint LM Test for Homoskedasticity in a One-Way error Component Model

This paper considers a general heteroskedastic error component model using panel data, and derives a joint LM test for homoskedasticity against the alternative of heteroskedasticity in both error components. It contrasts this joint LM test with marginal LM tests that ignore the heteroskedasticity in one of the error components. Monte Carlo results show that misleading inference can occur when using marginal rather than joint tests when heteroskedasticity is present in both components

Testing the Fixed Effects Restrictions? A Monte Carlo Study of Chamberlain\u27s Minimum Chi-Squared Test

Chamberlain (1982) showed that the fixed effects (FE) specification imposes testable restrictions on the coefficients from regressions of all leads and lags of dependent variables on all leads and lags of independent variables. Angrist and Newey (1991) suggested computing this test statistic as the degrees of freedom times the R2 from a regression of within residuals on all leads and lags of the exogenous variables. Despite the simplicity of these tests, they are not commonly used in practice. Instead, a Hausman (1978) test is used based on a contrast of the fixed and random effects specifications. We advocate the use of the Chamberlain (1982) test if the researcher wants to settle on the FE specifications, we check this test\u27s performance using Monte Carlo experiments, and we apply it to the crime example of Cornwell and Trumbull (1994)

Panel Unit Root Tests and Spatial Dependence

This paper studies the performance of panel unit root tests when spatial effects are present that account for cross-section correlation. Monte Carlo simulations show that there can be considerable size distortions in panel unit root tests when the true specification exhibits spatial error correlation. These tests are applied to a panel data set on net real income from the 1000 largest French communes observed over the period 1985-1998

Sieving and clogging in PEG-PEGDA hydrogel membranes

Hydrogels are promising systems for separation applications due to their structural characteristics (i.e. hydrophilicity and porosity). In our study, we investigate the permeation of suspensions of rigid latex particles of different sizes through free-standing hydrogel membranes prepared by photopolymerization of a mixture of poly (ethylene glycol) diacrylate (PEGDA) and large poly (ethylene glycol) (PEG) chains of 300 000 g.mol-1 in the presence of a photoinitiator. Atomic force microscopy (AFM) and cryoscanning electron microscopy (cryoSEM) were employed to characterize the structure of the hydrogel membranes. We find that the 20 nm particle permeation depends on both the PEGDA/PEG composition and the pressure applied during filtration. In contrast, we do not measure a significant permeation of the 100 nm and 1 $\mu$m particles, despite the presence of large cavities of 1 $\mu$m evidenced by cryoSEM images. We suggest that the PEG chains induce local nanoscale defects in the cross-linking of PEGDA-rich walls separating the micron size cavities, that control the permeation of particles and water. Moreover, we discuss the decline of the permeation flux observed in the presence of latex particles, compared to that of pure water. We suggest that a thin layer of particles forms on the surface of the hydrogels

Standardization for Defence Procurement - European Handbook : CEN Workshop 10

The European Commission (EC), DG Enterprise, endeavours the competitiveness of the European Defence Industry. The plethora of (national) standards, more than 10.000, are recognised by the EC as a major constraint and cost driver. Electromagnetic Compatibility (EMC) or Electromagnetic Environmental Effects (EEE) are considered by the EC as a major topic, with 7 other topics such as environmental engineering, energetic materials, batteries, electrical interfaces. An EMC expert group with representatives from industry, including Aerotech Telub, Intellect, EADS, Ericsson Microwave, Fincantieri, MBDA, Thales, and national MoDs rationalized in 2004 a list of 329 EEE standards, implicitly abandoning national, including American, standards, and develop guidelines for the procurement process. A limited number of widely accepted and cost effective standards, suitable for use by MoD’s (acquisition) and industry (product development), has been defined after making comparisons. Comparisons were carried out on some standards against STANAG 4370 AECTP 500. The Expert Group agreed; That no one standard is better or worse than another in achieving an end goal. Differences are not sufficient to prevent the use of AECTP 500. There are sufficient similarities to AECTP 500 to adopt this as the fundamental replacement standard. There was sufficient agreement on NATO-, IEC- and EN-produced standards to make worthwhile agreement to use a number of standards as replacement for some (or some parts) of existing National Standards. This document gives recommendations on the use of the standards, the scope and \ud limitations. It also emphasizes the constraints with respect to the standardisation process of National MoD’s, NATO, Industry and EN/IEC

Study of the atmospheric refraction in a single mode instrument - Application to AMBER/VLTI

International audienceThis paper presents a study of the atmospheric refraction and its effect on the light coupling efficiency in an instrument using single-mode optical fibers. We show the analytical approach which allowed us to assess the need to correct the refraction in J- and H-bands while observing with an 8-m Unit Telescope. We then developed numerical simulations to go further in calculations. The hypotheses on the instrumental characteristics are those of AMBER (Astronomical Multi BEam combineR), the near infrared focal beam combiner of the Very Large Telescope Interferometric mode (VLTI), but most of the conclusions can be generalized to other single-mode instruments. We used the software package caos (Code for Adaptive Optics Systems) to take into account the atmospheric turbulence effect after correction by the ESO system MACAO (Multi-Application Curvature Adaptive Optics). The opto-mechanical study and design of the system correcting the atmospheric refraction on AMBER is then detailed. We showed that the atmospheric refraction becomes predominant over the atmospheric turbulence for some zenith angles z and spectral conditions: for z larger than 30° in J-band for example. The study of the optical system showed that it allows to achieve the required instrumental performance in terms of throughput in J- and H-bands. First observations in J-band of a bright star, alpha Cir star, at more than 30° from zenith clearly showed the gain to control the atmospheric refraction in a single mode instrument, and validated the operating law

Pleasure in Understanding, Pleasure in Not Understanding

This paper looks at Alain Resnais’ Last Year in Marienbad (1961) and Chris Marker’s La Jetée (1962). It rests on a premise of film as a constructed, ordered world that answers only to itself. Both films address particular questions about time: what happens to our anticipation of the future if we move back and forth in time reinventing our past and present? (Marienbad) or, can we escape our ruined present by moving into the future? (La Jetée). From Jacques Lacan, it borrows the concepts of the mirror stage by which we recognise ourselves, and of the objet petit a, the looking for which (both in terms of ‘search’ and ‘seeing’) is that from which we derive our pleasure. From Jean-Luc Nancy it adopts descriptions of how film touches us, and the careful orchestration of the pleasure that is jouissance in being within this moment, not knowing where we are going

XRCC1 interacts with the p58 subunit of DNA Pol α-primase and may coordinate DNA repair and replication during S phase

Repair of single-stranded DNA breaks before DNA replication is critical in maintaining genomic stability; however, how cells deal with these lesions during S phase is not clear. Using combined approaches of proteomics and in vitro and in vivo protein–protein interaction, we identified the p58 subunit of DNA Pol α-primase as a new binding partner of XRCC1, a key protein of the single strand break repair (SSBR) complex. In vitro experiments reveal that the binding of poly(ADP-ribose) to p58 inhibits primase activity by competition with its DNA binding property. Overexpression of the XRCC1-BRCT1 domain in HeLa cells induces poly(ADP-ribose) synthesis, PARP-1 and XRCC1-BRCT1 poly(ADP-ribosyl)ation and a strong S phase delay in the presence of DNA damage. Addition of recombinant XRCC1-BRCT1 to Xenopus egg extracts slows down DNA synthesis and inhibits the binding of PCNA, but not MCM2 to alkylated chromatin, thus indicating interference with the assembly of functional replication forks. Altogether these results suggest a critical role for XRCC1 in connecting the SSBR machinery with the replication fork to halt DNA synthesis in response to DNA damage