Improving Privacy Settings for Facebook by Using Interpersonal Distance as Criterion

The possibility to define custom privacy settings in Facebook has been improved over the last years. Still,numerous users do not know how to change those settings or do not use the settings because they are cumbersome to use. Within this paper a new method for defining the privacy settings in online social networks is presented that uses the social distance between users as setting criterion. This approach was tested as a paper prototype in a first user study with 10 participants. Results show that the number of errors was significantly decreased and that the subjective evaluation of the interface was promising

Chytrid parasitism facilitates trophic transfer between bloom-forming cyanobacteria and zooplankton (Daphnia)

Parasites are rarely included in food web studies, although they can strongly alter trophic interactions. In aquatic ecosystems, poorly grazed cyanobacteria often dominate phytoplankton communities, leading to the decoupling of primary and secondary production. Here, we addressed the interface between predator-prey and host-parasite interactions by conducting a life-table experiment, in which four Daphnia galeata genotypes were maintained on quantitatively comparable diets consisting of healthy cyanobacteria or cyanobacteria infected by a fungal (chytrid) parasite. In four out of five fitness parameters, at least one Daphnia genotype performed better on parasitised cyanobacteria than in the absence of infection. Further treatments consisting of purified chytrid zoospores and heterotrophic bacteria suspensions established the causes of improved fitness. First, Daphnia feed on chytrid zoospores which trophically upgrade cyanobacterial carbon. Second, an increase in heterotrophic bacterial biomass, promoted by cyanobacterial decay, provides an additional food source for Daphnia. In addition, chytrid infection induces fragmentation of cyanobacterial filaments, which could render cyanobacteria more edible. Our results demonstrate that chytrid parasitism can sustain zooplankton under cyanobacterial bloom conditions, and exemplify the potential of parasites to alter interactions between trophic levels

Societal effects of transdisciplinary sustainability research—How can they be strengthened during the research process?

Transdisciplinary sustainability research aims to mitigate or to solve complex societal problems and advance the production of scientific knowledge. Reflexive approaches to transdisciplinary research processes are outlined to systematically strengthen the potential for societal effectiveness. So far, it is rare to find empirically based analyses of the links between the quality of the research process and the methods applied on the one hand and the effects achieved on the other. This paper thus addresses the issue of heightening the societal effects of transdisciplinary sustainability research. The objective is to explore ways of consciously promoting societal effectiveness in transdisciplinary research. We argue that these possibilities evolve at the intersection between the general project framework and an adaptive shaping of transdisciplinary research processes. A reflexive approach of this kind proactively considers the dynamics of interests and concerns, roles and responsibilities, the collaboration culture within a project, and the connectivity to the context of action addressed. Its deployment presupposes an appreciation of the basic conditions, i.e. the historical development of the respective problem, the heterogeneity of actors involved, the general environment and, finally, the funding conditions

The Headscarf Effect Revisited:Further Evidence for a Culture-Based Internal Face Processing Advantage

© 2015 a Pion publication. Encoding the internal features of unfamiliar faces poses a perceptual challenge that occasionally results in face recognition errors. Extensive experience with faces framed by a headscarf may, however, enhance perceivers’ ability to process internal facial information. To examine this claim empirically, participants in the United Arab Emirates and the United States of America completed a standard part-whole face recognition task. Accuracy on the task was examined using a 2 (perceiver culture: Emirati vs American) × 2 (face race: Arab vs white) × 2 (probe type: part vs whole) × 3 (probe feature: eyes vs nose vs mouth) mixed-measures analysis of variance. As predicted, Emiratis outperformed Americans on the administered task. Although their recognition advantage occurred regardless of probe type, it was most pronounced for Arab faces and for trials that captured the processing of nose or mouth information. The findings demonstrate that culture-based experiences hone perceivers’ face processing skills

Selection strategies for the development of maize introgression populations

Introgression libraries are valuable resources for QTL detection and breeding, but their development is costly and time-consuming. Selection strategies for the development of introgression populations with a limited number of individuals and high-throughput (HT) marker assays are required. The objectives of our simulation study were to design and compare selection strategies for the development of maize introgression populations of 100 lines with population sizes of 360–720 individuals per generation for different DH and S2 crossing schemes. Pre-selection for complete donor chromosomes or donor chromosome halves reduced the number of simultaneous backcross programs. The investigated crossing and selection schemes differed considerably with respect to their suitability to create introgression populations with clearly separated, evenly distributed target donor chromosome segments. DH crossing schemes were superior to S2 crossing schemes, mainly due to complete homozygosity, which greatly reduced the total number of disjunct genome segments in the introgression populations. The S2 crossing schemes were more flexible with respect to selection and provided economic alternatives to DH crossing schemes. For the DH crossing schemes, increasing population sizes gradually over backcross generations was advantageous as it reduced the total number of required HT assays compared to constant population sizes. For the S2 crossing schemes, large population sizes in the final backcross generation facilitated selection for the target segments in the final backcross generation and reduced fixation of large donor chromosome segments. The suggested crossing and selection schemes can help to make the genetic diversity of exotic germplasm available for enhancing the genetic variation of narrow-based breeding populations of crops

Metabolism of remimazolam in primary human hepatocytes during continuous long-term infusion in a 3-D bioreactor system

Background: Remimazolam is an ultra-short acting benzodiazepine under development for procedural sedation and general anesthesia. It is hydrolyzed by CES1 to an inactive metabolite (CNS7054). Purpose: In this study, the effect of continuous remimazolam exposure on its metabolism and on CES1 expression was investigated in a dynamic 3-D bioreactor culture model inoculated with primary human hepatocytes. Methods: Remimazolam was continuously infused into bioreactors for 5 days at a final concentration of 3,000 ng/ml (6.8 μM). In parallel, 2-D cultures were run with cells from the same donors, but with discontinuous exposure to remimazolam. Results: Daily measurement of clinical chemistry parameters (glucose, lactate, urea, ammonia, and liver enzymes) in culture supernatants indicated no noxious effect of remimazolam on hepatocyte integrity as compared to untreated controls. Concentrations of remimazolam reached steady-state values of around 250 ng/ml within 8 hours in 3-D bioreactors whereas in 2-D cultures remimazolam concentrations declined to almost zero within the same time frame. Levels of CNS7054 showed an inverse time-course reaching average values of 1,350 ng/ml in perfused 3-D bioreactors resp. 2,800 ng/ml in static 2-D cultures. Analysis of mRNA expression levels of CES1 indicated no changes in gene expression over the culture period. Conclusion: The results indicated a stable metabolism of remimazolam during 5 days of continuous exposure to clinically relevant concentrations of the drug. Moreover, there was no evidence for a harmful effect of remimazolam exposure on the integrity and metabolic activity of in vitro cultivated primary human hepatocytes

MTO1 mediates tissue specificity of OXPHOS defects via tRNA modification and translation optimization, which can be bypassed by dietary intervention

Mitochondrial diseases often exhibit tissue-specific pathologies, but this phenomenon is poorly understood. Here we present regulation of mitochondrial translation by the Mitochondrial Translation Optimization Factor 1, MTO1, as a novel player in this scenario. We demonstrate that MTO1 mediates tRNA modification and controls mitochondrial translation rate in a highly tissue-specific manner associated with tissue-specific OXPHOS defects. Activation of mitochondrial proteases, aberrant translation products, as well as defects in OXPHOS complex assembly observed in MTO1 deficient mice further imply that MTO1 impacts translation fidelity. In our mouse model, MTO1-related OXPHOS deficiency can be bypassed by feeding a ketogenic diet. This therapeutic intervention is independent of the MTO1-mediated tRNA modification and involves balancing of mitochondrial and cellular secondary stress responses. Our results thereby establish mammalian MTO1 as a novel factor in the tissue-specific regulation of OXPHOS and fine tuning of mitochondrial translation accurac

Retroviruses use CD169-mediated trans-infection of permissive lymphocytes to establish infection

Dendritic cells can capture and transfer retroviruses in vitro across synaptic cell-cell contacts to uninfected cells, a process called trans-infection. Whether trans-infection contributes to retroviral spread in vivo remains unknown. Here, we visualize how retroviruses disseminate in secondary lymphoid tissues of living mice. We demonstrate that murine leukemia virus (MLV) and human immunodeficiency virus (HIV) are first captured by sinus-lining macrophages. CD169/Siglec-1, an I-type lectin that recognizes gangliosides, captures the virus. MLV-laden macrophages then form long-lived synaptic contacts to trans-infect B-1 cells. Infected B-1 cells subsequently migrate into the lymph node to spread the infection through virological synapses. Robust infection in lymph nodes and spleen requires CD169, suggesting that a combination of fluid-based movement followed by CD169-dependent trans-infection can contribute to viral spread

High throughput screening identifies modulators of histone deacetylase inhibitors

Background Previous studies from our laboratory and others have demonstrated that in addition to altering chromatin acetylation and conformation, histone deacetylase inhibitors (HDACi) disrupt the acetylation status of numerous transcription factors and other proteins. A whole genome yeast deletion library screen was used to identify components of the transcriptional apparatus that modulate the sensitivity to the hydroxamic acid-based HDACi, CG-1521. Results Screening 4852 haploid Saccharomyces cerevisiae deletion strains for sensitivity to CG-1521 identifies 407 sensitive and 80 resistant strains. Gene ontology (GO) enrichment analysis shows that strains sensitive to CG-1521 are highly enriched in processes regulating chromatin remodeling and transcription as well as other ontologies, including vacuolar acidification and vesicle-mediated transport. CG-1521-resistant strains include those deficient in the regulation of transcription and tRNA modification. Components of the SAGA histone acetyltransferase (HAT) complex are overrepresented in the sensitive strains, including the catalytic subunit, Gcn5. Cell cycle analysis indicates that both the wild-type and gcn5Δ strains show a G1 delay after CG-1521 treatment, however the gcn5Δ strain displays increased sensitivity to CG-1521-induced cell death compared to the wild-type strain. To test whether the enzymatic activity of Gcn5 is necessary in the response to CG-1521, growth assays with a yeast strain expressing a catalytically inactive variant of the Gcn5 protein were performed and the results show that this strain is less sensitive to CG-1521 than the gcn5Δ strain. Conclusion Genome-wide deletion mutant screening identifies biological processes that affect the sensitivity to the HDAC inhibitor CG-1521, including transcription and chromatin remodeling. This study illuminates the pathways involved in the response to CG-1521 in yeast and provides incentives to understand the mechanisms of HDAC inhibitors in cancer cells. The data presented here demonstrate that components of the SAGA complex are involved in mediating the response to CG-1521. Additional experiments suggest that functions other than the acetyltransferase activity of Gcn5 may be sufficient to attenuate the effects of CG-1521 on cell growth

A cautionary note on the use of Ornstein Uhlenbeck models in macroevolutionary studies

Phylogenetic comparative methods are increasingly used to give new insights into the dynamics of trait evolution in deep time. For continuous traits the core of these methods is a suite of models that attempt to capture evolutionary patterns by extending the Brownian constant variance model. However, the properties of these models are often poorly understood, which can lead to the misinterpretation of results. Here we focus on one of these models – the Ornstein Uhlenbeck (OU) model. We show that the OU model is frequently incorrectly favoured over simpler models when using Likelihood ratio tests, and that many studies fitting this model use datasets that are small and prone to this problem. We also show that very small amounts of error in datasets can have profound effects on the inferences derived from OU models. Our results suggest that simulating fitted models and comparing with empirical results is critical when fitting OU and other extensions of the Brownian model. We conclude by making recommendations for best practice in fitting OU models in phylogenetic comparative analyses, and for interpreting the parameters of the OU model