293 research outputs found
What’s New about Whatsapp for News? A Mixed-Method Study on News Outlets’ Strategies for Using WhatsApp
Recent reports show that users increasingly use smartphone messenger applications such as WhatsApp for news. Media outlets have started to provide news via WhatsApp in addition to other platforms. In journalism scholarship, the routines of messenger app journalism are still little understood. Building on the Diffusions of Innovations theory, this paper explores whether newsrooms treat WhatsApp similar to other social media, which they have used for a longer period of time, or whether they have developed new practices that respect WhatsApp’s roots in mobile and interpersonal communication. Focusing on Germany as a case study and drawing on an analysis of 3745 messages sent to WhatsApp channels of news outlets and on an online survey of journalists working with social media (N=111), this study shows that journalists utilize the innovative possibilities of WhatsApp for news to a varying degree. While some characteristics of mobile communication are considered in news outlets’ strategies, engagement with the audience is often neglected. The results highlight the challenges for relational innovations in the editorial process
Rifting of the oceanic Azores Plateau with episodic volcanic activity
Extension of the Azores Plateau along the Terceira Rift exposes a lava sequence on the steep northern flank of the Hirondelle Basin. Unlike typical tholeiitic basalts of oceanic plateaus, the 1.2 km vertical submarine stratigraphic profile reveals two successive compositionally distinct basanitic to alkali basaltic eruptive units. The lower unit is volumetrically more extensive with similar to 1060 m of the crustal profile forming between similar to 2.02 and similar to 1.66 Ma, followed by a second unit erupting the uppermost similar to 30 m of lavas in similar to 100 kyrs. The age of similar to 1.56 Ma of the youngest in-situ sample at the top of the profile implies that the 35 km-wide Hirondelle Basin opened after this time along normal faults. This rifting phase was followed by alkaline volcanism at D. JoAo de Castro seamount in the basin center indicating episodic volcanic activity along the Terceira Rift. The mantle source compositions of the two lava units change towards less radiogenic Nd, Hf, and Pb isotope ratios. A change to less SiO2-undersaturated magmas may indicate increasing degrees of partial melting beneath D. JoAo de Castro seamount, possibly caused by lithospheric thinning within the past 1.5 million years. Our results suggest that rifting of oceanic lithosphere alternates between magmatically and tectonically dominated phases.Peer reviewe
Deeply dredged submarine HIMU glasses from the Tuvalu Islands, Polynesia: Implications for volatile budgets of recycled oceanic crust
Ocean island basalts (OIB) with extremely radiogenic Pb-isotopic signatures are melts of a mantle component called HIMU (high µ, high 238U/204Pb). Until now, deeply dredged submarine HIMU glasses have not been available, which has inhibited complete geochemical (in particular, volatile element) characterization of the HIMU mantle. We report major, trace and volatile element abundances in a suite of deeply dredged glasses from the Tuvalu Islands. Three Tuvalu glasses with the most extreme HIMU signatures have F/Nd ratios (35.6 ± 3.6) that are higher than the ratio (∼21) for global OIB and MORB, consistent with elevated F/Nd ratios in end-member HIMU Mangaia melt inclusions. The Tuvalu glasses with the most extreme HIMU composition have Cl/K (0.11–0.12), Br/Cl (0.0024), and I/Cl (5–6 × 10−5) ratios that preclude significant assimilation of seawater-derived Cl. The new HIMU glasses that are least degassed for H2O have low H2O/Ce ratios (75–84), similar to ratios identified in end-member OIB glasses with EM1 and EM2 signatures, but significantly lower than H2O/Ce ratios (119–245) previously measured in melt inclusions from Mangaia. CO2-H2O equilibrium solubility models suggest that these HIMU glasses (recovered in two different dredges at 2500–3600 m water depth) have eruption pressures of 295–400 bars. We argue that degassing is unlikely to significantly reduce the primary melt H2O. Thus, the lower H2O/Ce in the HIMU Tuvalu glasses is a mantle signature. We explore oceanic crust recycling as the origin of the low H2O/Ce (∼50–80) in the EM1, EM2, and HIMU mantle domains
Interatomic potentials for atomistic simulations of the Ti-Al system
Semi-empirical interatomic potentials have been developed for Al, alpha-Ti,
and gamma-TiAl within the embedded atomic method (EAM) by fitting to a large
database of experimental as well as ab-initio data. The ab-initio calculations
were performed by the linear augmented plane wave (LAPW) method within the
density functional theory to obtain the equations of state for a number of
crystal structures of the Ti-Al system. Some of the calculated LAPW energies
were used for fitting the potentials while others for examining their quality.
The potentials correctly predict the equilibrium crystal structures of the
phases and accurately reproduce their basic lattice properties. The potentials
are applied to calculate the energies of point defects, surfaces, planar faults
in the equilibrium structures. Unlike earlier EAM potentials for the Ti-Al
system, the proposed potentials provide reasonable description of the lattice
thermal expansion, demonstrating their usefulness in the molecular dynamics or
Monte Carlo studies at high temperatures. The energy along the tetragonal
deformation path (Bain transformation) in gamma-TiAl calculated with the EAM
potential is in a fairly good agreement with LAPW calculations. Equilibrium
point defect concentrations in gamma-TiAl are studied using the EAM potential.
It is found that antisite defects strongly dominate over vacancies at all
compositions around stoichiometry, indicating that gamm-TiAl is an antisite
disorder compound in agreement with experimental data.Comment: 46 pages, 6 figures (Physical Review B, in press
Varicellovirus UL49.5 Proteins Differentially Affect the Function of the Transporter Associated with Antigen Processing, TAP
Cytotoxic T-lymphocytes play an important role in the protection against viral infections, which they detect through the recognition of virus-derived peptides, presented in the context of MHC class I molecules at the surface of the infected cell. The transporter associated with antigen processing (TAP) plays an essential role in MHC class I–restricted antigen presentation, as TAP imports peptides into the ER, where peptide loading of MHC class I molecules takes place. In this study, the UL49.5 proteins of the varicelloviruses bovine herpesvirus 1 (BHV-1), pseudorabies virus (PRV), and equine herpesvirus 1 and 4 (EHV-1 and EHV-4) are characterized as members of a novel class of viral immune evasion proteins. These UL49.5 proteins interfere with MHC class I antigen presentation by blocking the supply of antigenic peptides through inhibition of TAP. BHV-1, PRV, and EHV-1 recombinant viruses lacking UL49.5 no longer interfere with peptide transport. Combined with the observation that the individually expressed UL49.5 proteins block TAP as well, these data indicate that UL49.5 is the viral factor that is both necessary and sufficient to abolish TAP function during productive infection by these viruses. The mechanisms through which the UL49.5 proteins of BHV-1, PRV, EHV-1, and EHV-4 block TAP exhibit surprising diversity. BHV-1 UL49.5 targets TAP for proteasomal degradation, whereas EHV-1 and EHV-4 UL49.5 interfere with the binding of ATP to TAP. In contrast, TAP stability and ATP recruitment are not affected by PRV UL49.5, although it has the capacity to arrest the peptide transporter in a translocation-incompetent state, a property shared with the BHV-1 and EHV-1 UL49.5. Taken together, these results classify the UL49.5 gene products of BHV-1, PRV, EHV-1, and EHV-4 as members of a novel family of viral immune evasion proteins, inhibiting TAP through a variety of mechanisms
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Deeply dredged submarine HIMU glasses from the Tuvalu Islands, Polynesia: Implications for volatile budgets of recycled oceanic crust
Ocean island basalts (OIB) with extremely radiogenic Pb-isotopic signatures are melts of a mantle component called HIMU (high µ, high ²³⁸U/²⁰⁴Pb). Until now, deeply dredged submarine HIMU glasses have not been available, which has inhibited complete geochemical (in particular, volatile element) characterization of the HIMU mantle. We report major, trace and volatile element abundances in a suite of deeply dredged glasses from the Tuvalu Islands. Three Tuvalu glasses with the most extreme HIMU signatures have F/Nd ratios (35.6 ± 3.6) that are higher than the ratio (∼21) for global OIB and MORB, consistent with elevated F/Nd ratios in end-member HIMU Mangaia melt inclusions. The Tuvalu glasses with the most extreme HIMU composition have Cl/K (0.11–0.12), Br/Cl (0.0024), and I/Cl (5–6 × 10⁻⁵) ratios that preclude significant assimilation of seawater-derived Cl. The new HIMU glasses that are least degassed for H₂O have low H₂O/Ce ratios (75–84), similar to ratios identified in end-member OIB glasses with EM1 and EM2 signatures, but significantly lower than H₂O/Ce ratios (119–245) previously measured in melt inclusions from Mangaia. CO₂-H₂O equilibrium solubility models suggest that these HIMU glasses (recovered in two different dredges at 2500–3600 m water depth) have eruption pressures of 295–400 bars. We argue that degassing is unlikely to significantly reduce the primary melt H₂O. Thus, the lower H₂O/Ce in the HIMU Tuvalu glasses is a mantle signature. We explore oceanic crust recycling as the origin of the low H₂O/Ce (∼50–80) in the EM1, EM2, and HIMU mantle domains.This is the publisher’s final pdf. The article is copyrighted by American Geophysical Union and published by John Wiley & Sons, Inc. It can be found at: http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/%28ISSN%291525-2027/. The data used in this paper can be found in the supporting information at: http://onlinelibrary.wiley.com/doi/10.1002/2015GC00596
Comparative interactomics analysis of different ALS-associated proteins identifies converging molecular pathways
Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment available. An increasing number of genetic causes of ALS are being identified, but how these genetic defects lead to motor neuron degeneration and to which extent they affect common cellular pathways remains incompletely understood. To address these questions, we performed an interactomic analysis to identify binding partners of wild-type (WT) and ALS-associated mutant versions of ATXN2, C9orf72, FUS, OPTN, TDP-43 and UBQLN2 in neuronal cells. This analysis identified several known but also many novel binding partners of these proteins. Interactomes of WT and mutant ALS proteins were very similar except for OPTN and UBQLN2, in which mutations caused loss or gain of protein interactions. Several of the identified interactomes showed a high degree of overlap: shared binding partners of ATXN2, FUS and TDP-43 had roles in RNA metabolism; OPTN- and UBQLN2-interacting proteins were related to protein degradation and protein transport, and C9orf72 interactors function in mitochondria. To conf
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