Optimal random sampling designs in random field sampling

A Horvitz-Thompson predictor is proposed for spatial sampling when the characteristic of interest is modeled as a random field. Optimal sampling designs are deduced under this context. Fixed and variable sample size are considered

OPTIMAL RANDOM SAMPLING DESIGNS IN RANDOM FIELD SAMPLING

A Horvitz-Thompson predictor is proposed for spatial sampling when the characteristic of interest is modeled as a random field. Optimal sampling designs are deduced under this context. Fixed and variable sample size are considered.

ASSESSING ADMINISTRATION CHARGES FOR THE AFFILIATE IN INDIVIDUAL ACCOUNT SYSTEMS

In any pension system based on capitalization, affiliates have to cover certain explicit costs which in a pay-as-you-go system would be implicit. In this paper we set out a model based on Whitehouse (2000) and Diamond (1999) to enable the explicit costs borne by the affiliate both during his working life and his retirement period to be assessed. It also shows the relationships between the different ways of measuring the costs that make up the total price finally paid by the contributors. Included in the model is the notable effect that some factors -such as gaps in contribution profiles, account transfers and changes in salary profiles- have on projecting the costs borne by the affiliates. Finally we carry out an international comparison of administration costs from the point of view of the affiliate, focusing special attention on the countries of Latin America and Spain. This has a double objective: 1.- To test the validity of criticisms made by some researchers as to whether the new capitalization systems introduced in Latin America are too expensive to run for the affiliates. 2.- To serve as a reference for the individual pension scheme system in Spain. En un sistema de pensiones basado en la capitalización los afiliados deben hacer frentea unos costes explícitos que en el sistema de reparto son implícitos. En este trabajo sedesarrolla un modelo, basado en Whitehouse (2000) y Diamond (1999), que permite evaluarlas comisiones explícitas que soporta el afiliado, tanto durante la vida laboral como durante laetapa de jubilación y que, además, muestra la relación entre las diferentes medidas de loscostes que integran el precio total que finalmente pagan los cotizantes. En el modelo seintroduce el efecto de algunos aspectos que tienen una repercusión muy importante en laproyección de los costes que soportan los afiliados: ¿vacíos¿ en los perfiles de aportación,efecto de los traspasos de fondos y cambio en los perfiles de salarios. Por último, se realizauna comparación internacional de los costes de administración desde la óptica de los afiliadoscon un doble objetivo:1.-Contrastar la validez de la crítica realizada por algunos investigadores a los nuevossistemas de capitalización individual implantados en América Latina, en el sentido de que sonexcesivamente caros de gestionar para los afiliados.2.-Servir de referencia para el sistema de planes de pensiones individuales en España.Capitalización, Costes de Administración, Fondo de pensiones, América Latina. Capitalization, Administration Costs, Pension Funds, Latin America

Intercalation and dynamics of hydrated Fe2+ in the vermiculites from Santa Olalla and Ojén

Although the intercalation of Fe3+ into layered phyllosicilicates-especially into smectites-attracted much attention in the past two decades, the information about Fe2+ loaded phyllosilicates is sparse. Here we present an investigation of the Fe2+ exchanged vermiculites from Santa Olalla and Ojén (Andalusia, Spain) by means of Mössbauer spectroscopy. The room temperature Mössbauer spectra are very similar to those of the starting compounds (Na forms) except for a decrease of the contribution of structural Fe3+ and a concomitant increase of the contribution of Fe2+ sites, indicating an internal redox process. The extent of this redox reaction is different for the two vermiculites. Thus, the intercalated Fe2+ acts as an electron mediator from the external medium to the structural Fe3+ ions. A new component attributable to intercalated Fe2+ is practically invisible in the room temperature Mössbauer spectra, but increases strongly and continuously during cooling to 4.2 K, where it is the dominant feature of the Mössbauer patterns. At 4.2 K, its quadruple splitting amounts to 3.31 mm/s, which is in excellent agreement with the quadrupole slitting of Fe2+ coordinated to six water molecules in a highly symmetric octahedral arrangement. The strong decrease of the Mössbauer-Lamb factor of this component with increasing temperature indicates a weak bonding of the Fe 2+ in the interlayer space

An alternative perspective on projectivity of modules

Similar to the idea of relative projectivity, we introduce the notion of relative subprojectivity, which is an alternative way to measure the projectivity of a module. Given modules $M$ and $N$, $M$ is said to be {\em $N$-subprojective} if for every epimorphism $g:B \rightarrow N$ and homomorphism $f:M \rightarrow N$, then there exists a homomorphism $h:M \rightarrow B$ such that $gh=f$. For a module $M$, the {\em subprojectivity domain of $M$} is defined to be the collection of all modules $N$ such that $M$ is $N$-subprojective. A module is projective if and only if its subprojectivity domain consists of all modules. Opposite to this idea, a module $M$ is said to be {\em subprojectively poor}, or {\em $sp$-poor} if its subprojectivity domain is as small as conceivably possible, that is, consisting of exactly the projective modules. Properties of subprojectivity domains and $sp$-poor modules are studied. In particular, the existence of an $sp$-poor module is attained for artinian serial rings.Comment: Dedicated to the memory of Francisco Raggi; v2 some editorial changes. 'Right hereditary right perfect' replaced by the (equivalent) condition 'right hereditary semiprimary'; v3 a mistake corrected in the statements of Propositions 3.8 and 3.

FIELD OBSERVATIONS ON THE FLOWERING BEHAVIOR PATTERN OF FOUR GRASS GENERA

FIELD OBSERVATIONS ON THE FLOWERING BEHAVIOR PATTERN OF FOUR GRASS GENER

Analysis of the start to the first hurdle in 110m hurdles at the IAAF World Athletics Championships Beijing 2015

The purpose of this study was to use observational analysis to evaluate the relationships between variables measured at the start of the men’s 110 hurdles event and race performance itself. Data were obtained for competitors in 2015 IAAF World Athletics Ch ampionships, in Beijing, China. The athletes’ start was quantified by reaction time and time to the first hurdle; their action over the first hurdle was quantified by the take - off distance (i.e., the distance from the last step to the first hurdle), the la nding distance, and the total distance in the air over the first hurdle. Regression analyses revealed that the combination of one measure of the start (either reaction time or time to the first hurdle) and the measure of propulsion over the first hurdle (d istance in air over the first hurdle) predicted performance (SEE = 0.23 s in the heats, SEE = 0.16 s in the semi - finals, SEE = 0.09 s in the finals). In addition, looking at performances in the finals, where all athletes with available data used a seven - st ep approach to the first hurdle, inclusion of stride length data improved the prediction somewhat (SEE = 0.07 s). The results demonstrate that a combination of a fast start, rapid acceleration, and strong drive over the first hurdle quantifiably explains a nd contributes to performance in the men’s 110 m hurdles at the highest level

Combined use of the GGSFT data base and on Board Marine Collected Data to Model the Moho Beneath the Powell Basin, Antarctica

The Powell Basin is a small oceanic basin located at the NE end of the Antarctic Peninsula developed during the Early Miocene and mostly surrounded by the continental crusts of the South Orkney Microcontinent, South Scotia Ridge and Antarctic Peninsula margins. Gravity data from the SCAN 97 cruise obtained with the R/V Hespérides and data from the Global Gravity Grid and Sea Floor Topography (GGSFT) database (Sandwell and Smith, 1997) are used to determine the 3D geometry of the crustal-mantle interface (CMI) by numerical inversion methods. Water layer contribution and sedimentary effects were eliminated from the Free Air anomaly to obtain the total anomaly. Sedimentary effects were obtained from the analysis of existing and new SCAN 97 multichannel seismic profiles (MCS). The regional anomaly was obtained after spectral and filtering processes. The smooth 3D geometry of the crustal mantle interface obtained after inversion of the regional anomaly shows an increase in the thickness of the crust towards the continental margins and a NW-SE oriented axis of symmetry coinciding with the position of an older oceanic spreading axis. This interface shows a moderate uplift towards the western part and depicts two main uplifts to the northern and eastern sectors