Social Networking Site Use Resumption: A Model of Return Migration

This research explains why individuals resume using social networking sites (SNSs) after terminating their use. Drawing on return migration theory, we developed a theory-driven model of SNS resumption that includes two novel antecedents of SNS resumption behavior: nonuse-related dissatisfaction and use-related satisfaction. We also hypothesize that dispositional resistance to change moderates the impact of nonuse-related dissatisfaction and use-related satisfaction on resumption. We used a mixed methods approach to refine and evaluate the research model. Study 1 used the critical incident method to identify SNS-specific antecedents of nonuse-related satisfaction and use-related satisfaction, allowing us to refine the research model. Study 2 used structural equation modeling to evaluate our research model using two three-wave surveys: one with recent ex-users who recently decided to stop using and delete their profiles on Facebook and one with long-standing ex-users who stopped using and deleted their profiles on Facebook a long time ago. We found support for most relationships in our model: nonuse-related dissatisfaction and use-related satisfaction drive resumption intentions, and dispositional resistance moderates these relationships. Furthermore, we found that the time elapsed since users discontinued Facebook moderated these relationships such that the effect of nonuse-related dissatisfaction on resumption intention is stronger for recent ex-users and the effect of use-related satisfaction is stronger for long-standing ex-users. Our findings advance the understanding of resumption, an understudied behavior of the IT lifecycle and IT use and acceptance research

Orangutans (Pongo abelii) make flexible decisions relative to reward quality and tool functionality in a multi-dimensional tool-use task

This work was supported by the University of St Andrews and the Max Planck Institute for Evolutionary Anthropology. Isabelle Laumer was supported by a uni:docs fellowship of the University of Vienna, Alice Auersperg was supported by by FWF grants J 3404-B19 and P 29084, and Thomas Bugnyar by Y366-B17.Making economic decisions in a natural foraging situation that involves the use of tools, may require an animal to consider more levels of relational complexity than merely deciding between an immediate and a delayed food option. We used the same method previously used with Goffin´s cockatoos to investigate the orangutans’ flexibility for making the most profitable decisions when confronted with five different settings that included one or two different apparatuses, two different tools and two food items (one more preferred than the other). We found that orangutans made profitable decisions relative to reward quality, when the task required the subjects to select a tool over an immediately accessible food reward. Furthermore, most subjects were sensitive to work-effort when the immediate and the delayed option (directly accessible by using a tool) led to the same outcome. Most subjects continued to make profitable decisions that required taking into account the tool functionality. In a final multidimensional task design in which subjects had to simultaneously focus on two apparatuses, two reward qualities and two different tools, the orangutans chose the functional tool to access the high quality reward.Publisher PDFPeer reviewe

Spontaneous innovation of hook-bending and unbending in orangutans (Pongo abelii)

This work was supported by FWF Grants P-29084 and P-29075 to Alice Auersperg and by a uni:docs fellowship of the University of Vienna to Isabelle Laumer.Betty the crow astonished the scientific world as she spontaneously crafted hook-tools from straight wire in order to lift a basket out of vertical tubes. Recently it was suggested that this species’ solution was strongly influenced by predispositions from behavioural routines from habitual hook-tool manufacture. Nevertheless, the task became a paradigm to investigate tool innovation. Considering that young humans had surprising difficulties with the task, it was yet unclear whether the innovation of a hooked tool would be feasible to primates that lacked habitual hook making. We thus tested five captive orangutans in a hook bending and unbending task. Orangutans are habitually tool-using primates that have been reported to use but not craft hooked tools for locomotion in the wild. Two orangutans spontaneously innovated hook tools and four unbent the wire from their first trial on. Pre-experience with ready-made hooks had some effect but did not lead to continuous success. Further subjects improved the hook-design feature when the task required the subjects to bent the hook at a steeper angle. Our results indicate that the ability to represent and manufacture tools according to a current need does not require stereotyped behavioural routines, but can indeed arise innovatively. Furthermore, the present study shows that the capacity for hook tool innovation is not limited to large brained birds within non-human animals.Publisher PDFPeer reviewe

Self-assembly of ordered wurtzite/rock salt heterostructures—A new view on phase separation in MgxZn1−xO

The self-assembled formation of ordered, vertically stacked rocksalt/wurtzite Mg x Zn 1−xO heterostructures by planar phase separation is shown. These heterostructures form quasi “natural” two-dimensional hetero-interfaces between the different phases upon annealing of MgO-oversaturated wurtzite Mg x Zn 1−xO layers grown by plasma-assisted molecular beam epitaxy on c-plane sapphire substrates. The optical absorption spectra show a red shift simultaneous with the appearance of a cubic phase upon annealing at temperatures between 900 °C and 1000 °C. Transmission electron microscopy reveals that these effects are caused by phase separation leading to the formation of a vertically ordered rock salt/wurtzite heterostructures. To explain these observations, we suggest a phase separation epitaxy model that considers this process being initiated by the formation of a cubic (Mg,Zn)Al2O4 spinel layer at the interface to the sapphire substrate, acting as a planar seed for the epitaxial precipitation of rock salt Mg x Zn 1−xO. The equilibrium fraction x of magnesium in the resulting wurtzite (rock salt) layers is approximately 0.15 (0.85), independent of the MgO content of the as-grown layer and determined by the annealing temperature. This model is confirmed by photoluminescence analysis of the resulting layer systems after different annealing temperatures. In addition, we show that the thermal annealing process results in a significant reduction in the density of edge- and screw-type dislocations, providing the possibility to fabricate high quality templates for quasi-homoepitaxial growth

Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias.

The phylogenetic placement of the morphologically simple placozoans is crucial to understanding the evolution of complex animal traits. Here, we examine the influence of adding new genomes from placozoans to a large dataset designed to study the deepest splits in the animal phylogeny. Using site-heterogeneous substitution models, we show that it is possible to obtain strong support, in both amino acid and reduced-alphabet matrices, for either a sister-group relationship between Cnidaria and Placozoa, or for Cnidaria and Bilateria as seen in most published work to date, depending on the orthologues selected to construct the matrix. We demonstrate that a majority of genes show evidence of compositional heterogeneity, and that support for the Cnidaria + Bilateria clade can be assigned to this source of systematic error. In interpreting these results, we caution against a peremptory reading of placozoans as secondarily reduced forms of little relevance to broader discussions of early animal evolution

Shedding Light on Shadow IT: Definition, Related Concepts, and Consequences

The use of Information Technology (IT) without the approval and support of the IT department, called shadow IT, has challenged organizations to rethink ways to manage IT resources to cope with the use of unauthorized technologies within organizations. We review the literature on shadow IT to shed light on this phenomenon, discussing the conceptual definition and types, the related concepts, and its consequences. This study, then, is an effort to better understand the phenomenon based on the extant literature. We provide contributions by enhancing the emerging body of knowledge on shadow IT, as well as by suggesting research gaps to be addressed in future research in order to advance on the topic

Global Peak in Atmospheric Radiocarbon Provides a Potential Definition for the Onset of the Anthropocene Epoch in 1965

Anthropogenic activity is now recognised as having profoundly and permanently altered the Earth system, suggesting we have entered a human-dominated geological epoch, the ‘Anthropocene’. To formally define the onset of the Anthropocene, a synchronous global signature within geological-forming materials is required. Here we report a series of precisely-dated tree-ring records from Campbell Island (Southern Ocean) that capture peak atmospheric radiocarbon (14C) resulting from Northern Hemisphere-dominated thermonuclear bomb tests during the 1950s and 1960s. The only alien tree on the island, a Sitka spruce (Picea sitchensis), allows us to seasonally-resolve Southern Hemisphere atmospheric 14C, demonstrating the ‘bomb peak’ in this remote and pristine location occurred in the last-quarter of 1965 (October-December), coincident with the broader changes associated with the post-World War II ‘Great Acceleration’ in industrial capacity and consumption. Our findings provide a precisely-resolved potential Global Stratotype Section and Point (GSSP) or ‘golden spike’, marking the onset of the Anthropocene Epoch