Search results for "Logit"
showing 10 items of 265 documents
Chemical heterogeneities in the mantle: The equilibrium thermodynamic approach
2016
Abstract This study attempts to answer a simple and yet fundamental question in relation to our understanding of the chemical evolution of deep Earth and planetary interiors. Given two initially separate assemblages (lithologies) in chemical equilibrium can we predict the chemical and mineralogical compositions of the two assemblages when they are put together to form a new equilibrated system? Perhaps a common perception is that given sufficient time, the two assemblages will homogenize chemically and mineralogically, however from a chemical thermodynamic point of view, this is not the case. Certain petrological differences in terms of bulk composition, mineralogy and mineral abundance rem…
Dating of prograde metamorphic events deciphered from episodic zircon growth in rocks of the Dabie–Sulu UHP complex, China
2006
The timing of ultra-high pressure (UHP) metamorphism has been difficult to determine because of a lack of age constraints on crucial events, especially those occurring on the prograde path. New Sensitive High-Resolution Ion Microprobe (SHRIMP) U–Pb age and rare-earth element (REE) data of zircon are presented for UHP metamorphic rocks (eclogite, garnet peridotite, garnet pyroxenite, jadeite quartzite and garnet gneiss) along the Dabie–Sulu UHP complex of China. With multiphase metamorphic textures and index mineral inclusions within zircon, the Dabie data define three episodes of eclogite-facies metamorphism, best estimated at 242.1 ± 0.4 Ma, 227.2 ± 0.8 Ma and 219.8 ± 0.8 Ma. Eclogite-faci…
Eclogite xenoliths from Kimberley, South Africa — A case study of mantle metasomatism in eclogites
2009
Abstract Eclogite xenoliths from the Kimberley diamond mine dumps were studied for major, trace elements and oxygen isotopes. The suite consists of typical garnet and clinopyroxene rocks as well as kyanite-eclogites and olivine- or orthopyroxene-bearing samples. All samples have Al[6]/Al[4] ratios > 2 which indicate high equilibration pressures, i.e. in the eclogite stability field as opposed to pyroxenites. Most samples are modally and cryptically metasomatized and contain up to 10 vol.% phlogopite plus ilmenite and rutile. Trace element geochemical characteristics of phlogopite and Ti-oxides are similar to those described for metasomatized peridotite xenoliths from the Kaapvaal craton, an…
Nature and origin of eclogite xenoliths from kimberlites
2004
Abstract Eclogites from the Earth's mantle found in kimberlites provide important information on craton formation and ancient geodynamic processes because such eclogites are mostly Archean in age. They have equilibrated over a range of temperatures and pressures throughout the subcratonic mantle and some are diamond-bearing. Most mantle eclogites are bimineralic (omphacite and garnet) rarely with accessory rutiles. Contrary to their overall mineralogical simplicity, their broadly basaltic-picritic bulk compositions cover a large range and overlap with (but are not identical to) much younger lower grade eclogites from orogenic massifs. The majority of mantle eclogites have trace element geoc…
Heterogeneity in general practitioners’ preferences for quality improvement programs: a choice experiment and policy simulation in France
2016
International audience; Despite increasing popularity, quality improvement programs (QIP) have had modest and variable impacts on enhancing the quality of physician practice. We investigate the heterogeneity of physicians’ preferences as a potential explanation of these mixed results in France, where the national voluntary QIP – the CAPI – has been cancelled due to its unpopularity. We rely on a discrete choice experiment to elicit heterogeneity in physicians’ preferences for the financial and non-financial components of QIP. Using mixed and latent class logit models, results show that the two models should be used in concert to shed light on different aspects of the heterogeneity in prefer…
Rural tourism in Spain
2002
Abstract The aim of this study is to determine the features that characterize a new tourist class, called modern rural tourism, and to figure out the proportion of this market in one specific Spanish region. The geographical territory under study is El Alto Palancia, one of the best known rural resorts, within the Valencian region. In order to fulfil these goals, an empirical study was undertaken and an econometric model was applied afterwards. A wide set of variables has been selected for the Logit Binomial Model, which is shown to be useful in discriminating the modern from traditional tourists.
Eclogites and garnet pyroxenites: Similarities and differences
2010
Eclogites and garnet pyroxenites are genetically linked to basaltic precursors. Traditionally garnet pyroxenites are linked to fractionation of basaltic Magmas Over a range of mantle pressures and more recently they have been implicated in the genesis of ocean islands. in contrast eclogites are linked to the subduction of slab basalt and gabbro precursors which may be hydrothermally altered. Recently this subduction paradigm has been questioned. We present mineralogical, trace element and O isotopic data for eclogites and garnet pyroxenites that reveal some similarities but also important chemical and isotopic differences that support a distinct provenance (i.e., age and process). Continent…
A weighted logistic regression for conjoint analysis and Kansei engineering
2007
Customer needs for emotional satisfaction are increasingly being considered by product and service designers. While several existing methods such as conjoint analysis (CA), Kano model and quality function deployment support the translation of customer requirements into technical specifications, researchers are now working to develop methods aimed at integrating affective aspects into product design. Kansei engineering (KE) is a design philosophy that considers customer perceptions and emotions by adopting a multi-disciplinary approach. CA is a useful tool within a KE project. This article presents a methodology for conducting a KE project in early development phases. This methodology is bas…
Taste heterogeneity and latent preferences in the choice behaviour of freight transport operators
2013
In this paper we show that individual attitudes of road carriers and their latent preferences toward specific freight service attributes do play a role in determining their mode choices. Specifically, we contribute to the empirical literature on freight agents' mode choice by exploring the role of the "perceived importance" of the most relevant service dimensions in determining the attractiveness of two alternatives to "all-road" transport: logistics terminals and road-sea intermodal services. This is carried out through a revealed/stated preference experiment and a mixture of logit framework. Our results support the hypothesis that operators' attitudes towards time, punctuality and risk of…
Social networks and social activities promote cognitive functioning in both concurrent and prospective time: evidence from the SHARE survey
2018
The study aimed to investigate the role of social activities, social networks as well as socioeconomic status (SES) in influencing some aspects of cognitive functioning (immediate and delayed verbal recall tests and semantic verbal fluency) in elderly people over time. This analysis was conducted on a sample of 31,954 healthy elderly people (58% female, mean age 65.54 ± 9.74) interviewed in both the fourth and sixth waves of the Survey on Health, Aging and Retirement in Europe (SHARE), in 2011 and 2015. A structural equation model with measurement component was used to assess the relationship between cognitive function, social life and SES over time. Multilevel ordinal logistic regression w…