Friend-to-Friend Privacy Protection on Social Networking Sites: A Grounded Theory Study

Individual privacy settings allow members of Social Networking Sites (SNS) to share personal data with specifically selected contacts, such as close friends. This allows members to use SNS for sharing even more private data they would otherwise not want to share with all of their contacts. Although a considerable part of data sharing activities on SNS is limited to the direct contacts of its members, current research lacks insights on use and design of individual privacy settings. In this paper we investigate driving and inhibiting factors which explain the motivation of SNS members to use individual privacy settings. Thereby, we contribute a new facet to the general understanding of privacy protection behavior on SNS and also lay the ground for improving the design of individual privacy settings offered by SNS providers. We have drawn our results from a conducted grounded theory study based on 37 qualitative interviews with Facebook users

Who Cares? Content Sharing On Social Networking Sites: A Grounded Theory Study

Users of Social Networking Sites (SNS) consume SNS content by means of online social streams such as the newsfeed system on Facebook. In this regard, a Facebook newsfeed content may comprise different kinds of user generated content, but also editorial content provided by fan pages, business pages or advertisers. Before being displayed on the Facebook newsfeed, contents are automatically pre-selected based on information filtering algorithms. Information filtering algorithms, in the form of Facebook’s edgerank system, are challenged to address the growing diversity of SNS content, but also the preferences of individual users. Distinct know ledge about the preferences of users for different kinds of SNS content can efficiently improve or complement established information filtering techniques. In this study we investigate factors that determine the attractiveness of SNS content for users. Thereby, we contribute a new facet in the understanding and support of users’ needs with regard to their consumption of SNS content. Our results allow improvement of existing information filtering techniques and to anticipate information flows on SNS (e.g. for the sake of viral marketing). We have developed our results based on a grounded theory study founded on 37 qualitative interviews with Facebook users

Vergleich der pflanzenbaulichen Systemwirkungen vergorener und unvergorener Wirtschaftsdünger und Vergärung von pflanzlichen Koppelprodukten in einem Betriebssystem der ökologischen Landwirtschaft mit Viehhaltung

The influence of biogas production in organic farming systems on different agricultural aspects is being researched in a field trial on the research station Gladbacherhof of the University of Giessen. The investigations took place within a whole crop rotation including 7 different crops in 8 years: two years clover grass followed by winter wheat, potatoes, rye, peas, spelt and at last summer wheat with undersown clover grass. Intercrops were sown after winter cereals and peas. This crop rotation is able to feed an average livestock husbandry in organic farming (0.8 cows ha-1). Four different fertilizing systems are being compared: 1) solid manure ploughed under before seeding of crops, 2) slurry spread out in emerging winter cereals or ploughed under to summer crops, 20 % were applied to mustard-vetches catch crop 3) fermented slurry applied like system 2 and 4) fermented slurry plus fermentation of crop residues and catch crops. The systems with slurry have a slurry storage capacity of half a year. Fermentation takes place in two biogas reactors, one for slurry (fully mixed reactor) and another one for plant residues (percolation system). Total N efficiencies of manure and slurry fertilizing systems are comparable. Reasons for this are: a) the atmospheric nitrogen losses after spreading out slurry on the surface of the soil and b) the reduced biological N2 fixation by vetches after application of slurry before seeding due to the limitations in storage capacity. Fermentation of crop residues and catch crops increases to about 70 % the mobile fertiliser pool but the productivity of the whole system is not higher, because a) about 50 % of N is within the solid phase of fermentation residue with a wide C/N ratio (≈19) and b) harvest and storage of crop residues and catch crops decreases the N-loss potential in winter (NO3, N2O), but other losses related to harvest, storage and mainly to spreading back on the soil in spring time are affecting the N use efficiency of the system

THE USAGE OF INDIVIDUAL PRIVACY SETTINGS ON SOCIAL NETWORKING SITES - DRAWING DESIRED DIGITAL IMAGES OF ONESELF

Social networking sites (SNS) such as Facebook have created a new way for individuals to share personal data and interact with each other on the Internet. The disclosure of this personal data is directly tied to the existing relationships of individuals within an SNS. Individual privacy settings allow a selective disclosure of personal data to specific connected individuals. In this paper, we present first empirical insights of a grounded theory study, based on 37 qualitative interviews with Facebook users, which reveal factors that drive, or generally influence, the use of these individual privacy settings on SNS. By investigating this privacy protection behaviour towards connected individuals, so-called friends in Facebook\u27s terminology, we add new perspectives to existing theories of information privacy protection \u27individuals\u27 privacy protection behaviour in non-anonymous online environments. We have developed a conceptual model showing that the motivation to use individual privacy settings depends on a complex interplay between different factors. As important drivers, motives for using SNS, existing relationships and context of personal data disclosure have been identified. Building on those insights further allows development or improvement of general privacy controls for individuals interacting with each other on the Internet

Mapping sequence structure in the human lateral entorhinal cortex

Remembering event sequences is central to episodic memory and presumablysupported by the hippocampal-entorhinal region. We previously demonstrated that thehippocampus maps spatial and temporal distances between events encountered along a routethrough a virtual city (Deuker et al., 2016), but the content of entorhinal mnemonic representationsremains unclear. Here, we demonstrate that multi-voxel representations in the anterior-lateralentorhinal cortex (alEC) — the human homologue of the rodent lateral entorhinal cortex —specifically reflect the temporal event structure after learning. Holistic representations of thesequence structure related to memory recall and the timeline of events could be reconstructedfrom entorhinal multi-voxel patterns. Our findings demonstrate representations of temporalstructure in the alEC; dovetailing with temporal information carried by population signals in thelateral entorhinal cortex of navigating rodents and alEC activations during temporal memoryretrieval. Our results provide novel evidence for the role of the alEC in representing time forepisodic memory

Structuring time in human lateral entorhinal cortex

Episodic memories consist of event information linked to spatio-temporal context. Notably, the hippocampus is involved in the encoding, representation and retrieval of temporal relations that comprise a context, but it remains largely unclear how coding for elapsed time arises in the hippocampal-entorhinal region. The entorhinal cortex (EC), the main cortical input structure of the hippocampus, has been hypothesized to provide temporal tags for memories via contextual drift and recent evidence demonstrates that time can be decoded from population activity in the rodent lateral EC. Here, we use fMRI to show that the anterior-lateral EC (alEC), the human homologue region of rodent lateral EC, maps the temporal structure of events. Participants acquired knowledge about temporal and spatial relationships between object positions - dissociated via teleporters - along a fixed route through a virtual city. Multi-voxel pattern similarity in alEC changed through learning to reflect elapsed time between event memories. Furthermore, we reconstructed the temporal structure of object relationships from alEC pattern similarity change. In contrast to the hippocampus, which maps the subjective time between event memories in this task, the temporal map in alEC reflected the objective time elapsed between events. Our findings provide evidence for the notion that alEC represents the temporal structure of memories, putatively derived from slowly-varying population signals during learning. Further, our findings suggest a dissociation between objective and subjective temporal maps in EC and hippocampus; thereby providing novel evidence for the role of the hippocampal-entorhinal region in representing time for episodic memory

Structuring time: The hippocampus constructs sequence memories that generalize temporal relations across experiences

The hippocampal-entorhinal region supports memory for episodic details, such as temporal relations of sequential events, and mnemonic constructions combining experiences for inferential reasoning. However, it is unclear whether hippocampal event memories reflect temporal relations derived from mnemonic constructions, event order, or elapsing time, and whether these sequence representations generalize temporal relations across similar sequences. Here, participants mnemonically constructed times of events from multiple sequences using infrequent cues and their experience of passing time. After learning, event representations in the anterior hippocampus reflected temporal relations based on constructed times. Temporal relations were generalized across sequences, revealing distinct representational formats for events from the same or different sequences. Structural knowledge about time patterns, abstracted from different sequences, biased the construction of specific event times. These findings demonstrate that mnemonic construction and the generalization of relational knowledge combine in the hippocampus, consistent with the simulation of scenarios from episodic details and structural knowledge

Mnemonic construction and representation of temporal structure in the hippocampal formation

The hippocampal-entorhinal region supports memory for episodic details, such as temporal relations of sequential events, and mnemonic constructions combining experiences for inferential reasoning. However, it is unclear whether hippocampal event memories reflect temporal relations derived from mnemonic constructions, event order, or elapsing time, and whether these sequence representations generalize temporal relations across similar sequences. Here, participants mnemonically constructed times of events from multiple sequences using infrequent cues and their experience of passing time. After learning, event representations in the anterior hippocampus reflected temporal relations based on constructed times. Temporal relations were generalized across sequences, revealing distinct representational formats for events from the same or different sequences. Structural knowledge about time patterns, abstracted from different sequences, biased the construction of specific event times. These findings demonstrate that mnemonic construction and the generalization of relational knowledge combine in the hippocampus, consistent with the simulation of scenarios from episodic details and structural knowledge

Grid-cell representations in mental simulation

Anticipating the future is a key motif of the brain, possibly supported by mental simulation of upcoming events. Rodent single-cell recordings suggest the ability of spatially tuned cells to represent subsequent locations. Grid-like representations have been observed in the human entorhinal cortex during virtual and imagined navigation. However, hitherto it remains unknown if grid-like representations contribute to mental simulation in the absence of imagined movement. Participants imagined directions between building locations in a large-scale virtual-reality city while undergoing fMRI without re-exposure to the environment. Using multi-voxel pattern analysis, we provide evidence for representations of absolute imagined direction at a resolution of 30° in the parahippocampal gyrus, consistent with the head-direction system. Furthermore, we capitalize on the six-fold rotational symmetry of grid-cell firing to demonstrate a 60° periodic pattern-similarity structure in the entorhinal cortex. Our findings imply a role of the entorhinal grid-system in mental simulation and future thinking beyond spatial navigation

Biogaserzeugungspotential aus Gülle und Koppelprodukten in viehhaltenden und viehlosen Betriebssystemen des ökologischen Landbaus

In two agricultural systems with and without animal husbandry the potential to produce renewable energy by digesting slurry and organic residues to biogas were assessed. In comparison to some other methods of energy production by biomass biogas production has the advantage of keeping the nutrients of the substrates within the agricultural system. They can be used as fertilisers. In the investigated system with milk production (0,8 cows ha-1, 8 crops, among them 4 cereals, peas, potatoes and 2 clover grasses with catch crops after winter cereals and peas (see DEUKER et al. 2005), it is possible not only to ferment slurry, but also catch crops and straw of peas and cereals. The methan production potential by digesting only slurry is the equivalent of around 327 l diesel fuel ha-1. By digesting a well developed catch crop it is possible to harvest the equivalent of around 750 l diesel fuel per ha.-1 sown with such crops. Related to the whole system with 4 catch crops within 8 fields it is possible just by including catch crops in the fermentation process with slurry to duplicate the methan harvest of the digesting plant to around 700 l diesel fuel ha-1 a-1. By utilisation of biomass like the straw of peas and other residues it is possible to generate the equivalent of approx. 450 l diesel fuel ha-1. Total biogas production potential by including all fermentable biomass is the equivalent of approx. 1150 l diesel fuel per each ha and year. Usually one third of this energy is necessary to temperate the digester, one third can be converted to electricity and one third can be used to heat buildings in the neighbourhood of the fermentation plant. In a typical stockless organic agricultural system composed of six crops (clover gras, potatoes, winter wheat, peas, winter wheat and summer wheat with undersown clover grass, with catch crops after winter wheat and peas, see STINNER et al. 2005) biomass of clover grass and catch crops will normally be left on the field and incorporated in the soil. By fermentation of clover grass there is a biogas production potential of around the equivalent of 3300 to 4700 l diesel fuel ha-1 a-1. Digesting catch crops allows a methan yield of ca. 650 to 700 l diesel fuel ha-1, digestion of other residues like straw other 1250 to 1350 l diesel ha-1. The total energy production potential of the whole crop rotation system is the equivalent of around 1700 to 1800 l diesel per ha and year. Removal of crop residues is coupled with removal of substantial quantities of nitrogen, reducing the residual mineralisable nitrogen amounts on fields at the end of the vegetation period and the risk of nitrate leaching