A time-space dynamic panel data model with spatial moving average errors

This paper focuses on the estimation and predictive performance of several estimators for the time-space dynamic panel data model with Spatial Moving Average Random Effects (SMA-RE) structure of the disturbances. A dynamic spatial Generalized Moments (GM) estimator is proposed which combines the approaches proposed by Baltagi, Fingleton and Pirotte (2014) and Fingleton (2008). The main idea is to mix non-spatial and spatial instruments to obtain consistent estimates of the parameters. Then, a forecasting approach is proposed and a linear predictor is derived. Using Monte Carlo simulations, we compare the short-run and long-run e¤ects and evaluate the predictive effficiencies of optimal and various suboptimal predictors using the Root Mean Square Error (RMSE) criterion. Last, our approach is illustrated by an application in geographical economics which studies the employment levels across 255 NUTS regions of the EU over the period 2001-2012, with the last two years reserved for prediction

A multidimensional spatial lag panel data model with spatial moving average nested random effects errors

This paper focuses on a three-dimensional model that combines two different types of spatial interaction effects, i.e. endogenous interaction effects via a spatial lag on the dependent variable and interaction effects among the disturbances via a spatial moving average (SMA) nested random effects errors. A three-stage procedure is proposed to estimate the parameters. In a first stage, the spatial lag panel data model is estimated using an instrumental variable (IV) estimator. In a second stage, a generalized moments (GM) approach is developed to estimate the SMA parameter and the variance components of the disturbance process using IV residuals from the first stage. In a third stage, to purge the equation of the specific structure of the disturbances a Cochrane–Orcutt-type transformation is applied combined with the IV principle. This leads to the GM spatial IV estimator and the regression parameter estimates. Monte Carlo simulations show that our estimators are not very different in terms of root mean square error from those produced by maximum likelihood. The approach is applied to European Union regional employment data for regions nested within countries

Basaltic Shergottite NWA 856: Differentiation of a Martian Magma

NWA 856 or Djel Ibone, is a basaltic shergottite discovered as a single stone of 320 g in South Morocco in April, 2001. This meteorite is fresh, i.e. shows minimal terrestrial weathering for a desert find. No shergottite discovered in North Africa can be paired with NWA 856. The purpose of this study is to constrain its crystallization history using textural observations, crystallization sequence modeling and in-situ trace element analysis in order to understand differentiation in shergottite magmatic systems

Cryogenic Facilities at 1.9 K for the Reception of the Superconducting Wires and Cables of the LHC Dipoles Magnets

CERN's LHC project has moved to an implementation phase. The fabrication of 1600 high-field superconducting magnets operating at 1.9 K will require about 6400 km of Nb-Ti cables. A cryogenic test facility has therefore been set up in order, on the one hand, to verify the quality of individual wires and, on the other hand, to control the critical current of the assembled cables. The facility is composed of a helium liquefier, a transfer line, a dewar and pumps. The paper describes the fully automatic operation of this installation and the different test cycles applied to these wires and cables

Heterogeneity and cross-sectional dependence in panels: Heterogeneous vs. homogeneous estimators

This paper focuses on the comparison of homogeneous and heterogeneous panel data estimators, including partially heterogeneous ones, in presence of cross-sectional dependence generated by common factors and spatial error dependence. Our specifications allow us to con-sider and contrast weak cross-sectional dependence and strong cross-sectional dependence in a general linear heterogeneous panel data model. An overview of the estimation procedures, including heterogeneous, homogeneous and partially heterogeneous estimators, is presented. Then, an extensive Monte Carlo study is conducted using a general framework encompassing recent contributions in the literature especially in terms of considering common factors and spatial dependence simultaneously. Our simulation results show that, even for small individual and time dimensions, heterogeneous estimators perform better in terms of bias, root mean squared error, size and size adjusted power compared to homogeneous estimators. Last, the superiority of the heterogeneous estimators is confirmed by an empirical application relating fiscal decentralization and government size in 22 OECD countries over the period 1973-2017

Renal infarction in an adolescent carrier of the sickle cell trait.

editorial reviewedWe report the case of a 15-year-old teenager, carrier of the sickle cell trait (haemoglobin AS), who presented a renal infarction. Besides, the patient also presented a renal ectopia. It is tempting to link these two particularities and the ischemic attack. The kidney is a target of this hemoglobinopathy, in its homozygous and possibly even heterozygous form. However, the analysis of the literature does not retain renal vascular accidents as a complication of sickle cell trait. Kidney position abnormalities also do not appear to be a contributing factor. It is, however, necessary to be attentive in adult heterozygous subjects to a faster than normal decline in glomerular filtration. The search for other risk factors (hypertension, diabetes, dyslipaemia) is desirable. The implementation of specific monitoring requires additional work

Cryogenic Characteristics of the ATLAS Barrel Toroid Superconducting Magnet

ATLAS, one of the experiments of the LHC accelerator under commissioning at CERN, is equipped with a large superconducting magnet the Barrel Toroid (BT) that has been tested at nominal current (20500 A). The BT is composed of eight race-track superconducting coils (each one weights about 45 tons) forming the biggest air core toroidal magnet ever built. By means of a large throughput centrifugal pump, a forced flow (about 10 liter/second at 4.5 K) provides the indirect cooling of the coils in parallel. The paper describes the results of the measurements carried out on the complete cryogenic system assembled in the ATLAS cavern situated 100 m below the ground level. The measurements include, among other ones, the static heat loads, i.e., with no or constant current in the magnet, and the dynamic ones, since additional heat losses are produced, during the current ramp-up or slow dump, by eddy currents induced on the coil casing

Reifying Design Patterns as Metalevel Constructs

A design pattern describes a structure of communicating components that solves a commonly occurring design problem. Designing with patterns offers the possibility of raising the abstraction level at which design is performed, with improvements in clarity, understanding, and facility of maintenance of applications. However, in their most common presentation, design patterns are informal pieces of design process, which application is not reflected in the operational system, and the potential advantages of a more principled design are not realized. This work proposes to organize design in such a way that pattern applications remain explicit in the operational systems. A reflective architecture is proposed, where patterns are reified as metalevel constructs.Sociedad Argentina de Informática e Investigación Operativ