Proposing the Multimotive Information Systems Continuance Model (MISC) to Better Explain End-User System Evaluations and Continuance Intentions

To ensure that users want to continue using a system, information system designers must consider the influence of users’ intrinsic motivations in addition to commonly studied extrinsic motivations. In an attempt to address this need, several studies have extended models of extrinsic motivation to include intrinsic variables. However, these studies largely downplay the role of users’ intrinsic motivations in predicting system use and how this role differs from that of extrinsic motivation. The role of met and unmet expectations related to system use is often excluded from extant models, and their function as cocreators in user evaluations has not been sufficiently explained. Even though expectations are a firmly established consequence of motivations and an antecedent of interaction evaluations, this area remains understudied. Our paper addresses these gaps by developing and testing a comprehensive model—the multimotive information systems continuance model (MISC)—that (1) explains more accurately and thoroughly the roles of intrinsic and extrinsic motivations, (2) explains how the fulfillment of intrinsic and extrinsic motivations affects systems-use outcome variables differently through met expectations, and (3) accounts for the effects of key design constructs

CAUGHT BETWEEN A ROCK AND A HARD MINERAL ENCRUSTATION: LONG-LIVED AQUATIC INSECTS ACCUMULATE CALCIUM CARBONATE DEPOSITS IN A MONTANE DESERT STREAM

Aquatic ecosystems overlying regions of limestone bedrock can feature active deposition of calcium carbonate in the form of travertine or tufa. Although most travertine deposits form a cement-like layer on stream substrates, mineral deposits can also form on benthic invertebrates. However, little is known about which taxa may be prone to calcium carbonate encrustation and which life history traits may make taxa more susceptible to becoming encrusted. Here we report the presence of calcium carbonate deposits on live insects collected from a montane stream in the Madrean Sky Islands (Huachuca Mountains) of Arizona between 2011 and 2013. Life history differences are examined between taxa with and without travertine deposits. Thirteen genera of aquatic insects were found with calcium carbonate deposits on the exoskeleton as well as 22 other genera, also encountered in the study stream, that have not previously been found with such deposits. Taxa with calcium carbonate encrustation had significantly longer-lived aquatic stages than those without encrustation. Furthermore, encrustation presence did not differ among aerial dispersal modes. These results suggest that the extent of calcium carbonate deposition on aquatic insects is primarily related to the length of time they are in the stream. Since mineral encrustation may reduce predation pressure and mobility, changes in patterns of travertine formation in these systems may have profound effects on ecological interactions. Los ecosistemas dulceacuícolas ubicados en regiones de roca caliza pueden contener depósitos de carbonato de calcio en forma de travertino o tufa. Aunque muchos depósitos de travertino se encuentran como una capa o manto de cemento sobre el fondo del arroyo, los depósitos también pueden formarse sobre los invertebrados bentónicos. Sin embargo, poco se sabe acerca de las especies que son propensas a los depósitos de travertino, o acerca de las características de estas especies que influyen en tal proceso. En este manuscrito reportamos la presencia de depósitos de travertino en insectos vivos y recolectados en un arroyo montañoso en el Archipiélago Madrense de Arizona durante 2011–2013 y examinamos las diferencias en las historias de vida entre taxones con o sin depósitos de travertino. Encontramos trece géneros de insectos acuáticos con travertino sobre el exoesqueleto y vientedos géneros sin travertino. Los taxones con travertino tienen una fase acuática significativamente más larga que los taxones sin travertino. Además, la presencia de travertino no difirió entre especies con distintas maneras de dispersión aérea. Estos resultados sugieren que las diferencias en los depósitos de travertino en insectos acuáticos ocurren principalmente a causa de la duración del período de vida acuática del insecto. Aunque los depósitos de travertino pueden reducir la presión por depredación y movilidad, cambios en los patrones de formación de travertino en estos sistemas pueden afectar profundamente las interacciones ecológicas

High-resolution Niche Models via a Correlative Approach: Comparing and Combining Correlative and Process-based Information

Correlative and process-based approaches to describing the ecological niche in a spatially explicit fashion have often been compared in an adversarial framework. We sought to compare niche models developed via classic (correlative only), niche (process-based information), and hybridized (correlative augmented with process-based derived information) approaches, with the goal of determining if the added effort of process-based model development yielded better model fit. Correlative data layers (i.e., habitat models) included vegetation community types, Euclidean distance statistics, neighborhood analyses, and topographically-derived information. Mechanistic data layers were estimates of thermal suitability derived from field-collected datasets and biophysical calculations, and estimates of prey biomass interpolated from monitoring stations. We applied these models at high resolution (1 m × 1 m pixel size) to habitat occupied by a population of Texas horned lizards (Phrynosoma cornutum) located in central Oklahoma. Results suggested that our treatment of process-based information offered dramatically better identification of suitable habitat when compared to correlative information, but that these results were likely due to low variability of niche variable pixel values. Niche layers nearly perfectly predicted lizard locations; the interpretation of these results suggest that lizards occupy habitat based on thermal suitability over the duration of a field season. Given the low variability observed in thermal suitability layers, we question the ecological reality of these predictions. Correlative models may accurately describe the niche at small spatial scales, and may suffice in situations where time and financial resources are limiting constraints on project goals. Process-based information continues to be an important part of the niche, and may offer additional predictive accuracy via correlative approaches when included in an ecologically meaningful context

Comparisons of Temporal and Spatial Trends in the Spatially Complete Global Spectral Surface Albedos Products

Five years of spatially complete snow-free land surface albedo data have been prepared using high quality white-sky and black-sky land surface albedo observations (MOD43B3) from the MODIS instrument aboard NASA's Terra satellite platform. The data were generated using an updated ecosystem-dependent temporal interpolation technique. In this paper, we describe the refinements in the technique and the creation of a spatially complete snow-free five-year aggregate climatology product. This paper also describes an error analysis of the interpolation technique. The filled albedo products are examined through comparisons of temporal and spatial trends for pixels that have been filled versus pixels that have been retained in the original MOD43B3 values. The variability in the trends showcase how the filling technique maintains the pixel-level spatial, spectral, and temporal integrity of the MOD43B3 data. These comparisons are made for both a single-year of filled data, year 2002, and for the five-year aggregate climatology product