The Use of PLS When Analyzing Formative Constructs: Theoretical Analysis and Results From Simulations

Partial Least Squares (PLS) has become an increasingly popular approach to testing research models with multiple proposed causality links. Moreover, recent interest in the specification of constructs in a formative manner has accentuated this tendency, given the purported ability of PLS to handle this methodological development. While a review of the literature reveals an extensive use of PLS in this capacity, there is neither theoretical nor empirical evidence supporting this property of the technique. An examination of the inner workings of PLS shows several limitations of PLS when used in \u27formative\u27 (Mode B) estimation, and compares it to linear regression and covariance-based approaches. Results from Monte Carlo simulations comparing the performance of PLS and covariance-based techniques in estimating models with formatively specified constructs in either exogenous or endogenous positions reveals important biases for PLS, but not for covariance-based SEM. The results are discussed and recommendations for researchers are proposed

A Monte Carlo Investigation of Partial Least Squares, With Implications for Both Structural and Measurement Models

Partial Least Squares (PLS) is a popular technique with extensive adoption within the Information Systems research community. However, the statistical performance of PLS has not been extensively studied, and recent research has questioned some of its purported advantages. The simulation study reported here analyzed the performance of PLS with regards to the recovery and estimation accuracy of both structural and measurement parameters. Somewhat surprisingly, the effects of estimation bias on the latter and their implications for the evaluation of measurement models have not been the focus of past research. Results show the existence of an important degree of bias in both sets of estimates, and the conflicting effect of increased sample size with additional indicators per composite variable

Primer registro de acumulaciones en masa de gastrópodos nerineidos en la Formación Agrio, Cretácico Inferior de Cuenca Neuquina, Argentina

El primer hallazgo de acumulaciones en masa de gastrópodos en la Formación Agrio proviene de la localidad de Lomas Bayas, Mendoza, Argentina. Las capas portadoras se ubican hacia el tope del Miembro Agua de la Mula. Su edad ha sido determinada como Hauteriviano Tardío cuspidal en base a la correlación con capas pertenecientes a la zona de amonoideos de Paraspiticeras groeberi. La asociación está compuesta por gastrópodos de la Familia Nerineidae. Las acumulaciones en masa se registraron en dos niveles estratigráficos distintos con una abundancia promedio de 300 conchillas por m2. Los ejemplares estudiados han sido determinados como Cossmannea (Eunerinea) sp. en base a los siguientes caracteres: conchilla cónica muy elongada, levemente cirtocónica, vueltas de caras planas a ligeramente cóncavas, región sutural suavemente convexa, corto canal anterior, abertura sub-cuadangular y tres pliegues internos (columelar, parietal y labial). Los especímenes se preservan como secciones axiales con conchilla recristalizada inmersas en la roca portadora y como moldes internos sueltos y fragmentarios. La gran mayoría se dispone en paralelo al plano de estratificación, con la abertura y/o ápice dañados, relleno concordante con la matriz y estructura geopetal. Estos rasgos tafonómicos sugieren un bajo grado de retrabajo y transporte lateral. Las rocas portadoras son grainstones oolíticos con rasgos de diagénesis marina somera. La presencia de fragmentos de corales coloniales y equinoideos asociados sugiere sustratos estables en probable cercanía con arrecifes en parche. Los nerineoideos son típicos de facies carbonáticas arrecifales y son considerados indicativos de condiciones tropicales a subtropicales. Si bien son frecuentes en depósitos mesozoicos, el hallazgo de acumulaciones en masa es en cambio excepcional y resulta de importancia paleoambiental y paleoecológica, dado que estaría relacionado al desarrollo de una estrategia de tipo oportunista bajo condiciones ambientales óptimas.Sesiones libresFacultad de Ciencias Naturales y Muse

HOW MANY TECHNOLOGY TYPES ARE THERE? PRELIMINARY RESULTS FROM THE TECHNOLOGY ACCEPTANCE LITERATURE

To investigate a generalizable moderating effect of the type of technology tested upon its acceptance, a classification of technologies is needed. This study aims to develop a preliminary framework to describe information technologies based upon 200 randomly selected technology descriptions taken from a comprehensive TAM meta-analysis effort currently in progress. We report on the use of a classification method involving both human judgment and statistical techniques. A manual sorting process is followed by multidimensional scaling (MDS) and cluster analysis to aggregate the individual interpretations of the sorters into hierarchical cluster structures. The results of this method reveal several potential technology grouping solutions, one of which was selected for further discussion. Limitations and future research are also discussed

Assessing orbital vs. volcanic control on carbon cycle during the Early Cretaceous

The interval from the Valanginian to the Barremian stages (137?121 Ma; Early Cretaceous) ispunctuated by several episodes of environmental changes, accompanied by shifts in weatheringintensity on the continents and changes in the Tethyan neritic carbonate production. Wesynthetize here the astrochronology of two recent studies performed in the Neuquén basin,Vocontian Basin and Subbetic Domain (Aguirre-Urreta et al., 2019; Martinez et al., 2020), anchoredto CA-ID-TIMS U-Pb ages, which conclusions have been included in the Geologic Time Scale 2020(Gale et al, in press). We applied this time scale to a compilation of carbon-isotope ratio frombelemnites and proxies of detrital supply in the Tethyan area (Vocontian Basin and SubbeticDomain). From this compilation, we show that the episodes of environmental changes are pacedby a 2.4-Myr cycle and, with a lower amplitude, a 1.2-Myr cycle. In addition, the new time scaleshows the synchronicity between the Weissert Event and the Parana-Etendeka Large IgneousProvince. In the series of carbon-isotope ratios measured on belemnite rostra, the amplitude ofthe 2.4-Myr cycle is twice higher during the Valanginian than in the Late Barremian and threetimes higher than in the Hauterivian and Early Barremian, suggesting that the activity of theParana-Etendeka Large Igneous Province amplified the initial orbital forcing to trigger theenvironmental changes observed during the Mid-Valanginian.Fil: Martinez, M.. Géosciences Rennes; FranciaFil: Aguirre Urreta, María Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lescano, Marina Aurora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Dera, G.. Université Paul Sabatier; FranciaFil: Omarini, Julieta. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Tunik, Maisa Andrea. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Frederichs, Tomas. Universitat Bremen; AlemaniaFil: Palike, Heiko. Université Paul Sabatier; FranciaFil: O'Dogherty, Luis. Universidad de Cádiz; EspañaFil: Aguado, Roque. Universidad de Jaén; EspañaFil: Company, Miguel. Universidad de Granada; EspañaFil: Sandoval, Jose. Universidad de Granada; EspañaEGU General Assembly 2021AlemaniaEuropean Geosciences Unio

A high-resolution belemnite geochemical analysis of Early Cretaceous (Valanginian-Hauterivian) environmental and climatic perturbations

International audienceThe Early Cretaceous Weissert event, characterized by a positive carbon isotope excursion and coincident with the Paraná-Etendeka volcanism, saw a biogeochemical chain of events that ultimately led to an increase in carbon burial. A conclusive link between the Paraná-Etendeka volcanism and its impact upon the environment remains, however, elusive. Here we reconstruct temperature through the Weissert event from Mg/Ca ratios of belemnites from the Vocontian Trough (France) and SE Spain and use carbon isotopes to link our temperature reconstruction to marine records of carbon cycling. We provide evidence that the Paraná-Etendeka volcanism, unlike some large igneous provinces, did not cause a climate warming. The case can be made for cooling in the last stages of the Weissert event, which possibly reflects substantial CO 2 drawdown. In the absence of warming and consequent accelerated hydrological cycling and the relatively long duration of the eruptive phase of the Paraná-Etendeka, an alternate trigger for increased fertilization of the oceans is implicated

Is it really gender? An empirical investigation into gender effects in technology adoption through the examination of individual differences

A recent development in the technology acceptance literature is the inclusion of gender as a moderator of the relationships between intention and its antecedents, such that some are stronger for men than women, and vice versa. While the effects have been well established, the mechanisms by which they operate, that is, which specific gender differences are in operation and how they affect intention to adopt, have not been thoroughly explored. In this research, psychological constructs with established gender differences, such as core self-evaluations, computer self-efficacy and anxiety, psychological gender-role, and risk-taking propensity, are examined. In addition, this research introduces a novel context for the study of technology adoption in that more than a single alternative is offered to participants, thus requiring a choice among technologies. Results indicate that gender effects are more complex than previously thought, with potentially multiple influences from different facets operating simultaneously

Upper Barremian Heteroceratinae (Cephalopoda, Ammonoidea) from Patagonia and Zululand, with comments on the systematics of the subfamily

Volume: 96Start Page: 315End Page: 35